ALBERT

Description: The ACT workshop "Enabling Sensor Interoperability" addressed the need for protocols at thehardware, firmware, and higher levels in order to attain instrument interoperability within and betweenocean observing systems. For the purpose of the workshop, participants spoke in tern of "instruments" rather than "sensors," defining an instrument as a device that contains one or more sensors or actuators and can convert signals from analog to digital.An increase in the abundance, variety, and complexity of instruments and observing systems suggeststhat effective standards would greatly improve "plug-and-work" capabilities. However, there are few standards or standards bodies that currently address instrument interoperability and configuration.Instrument interoperability issues span the length and breadth of these systems, from the measurementto the end user, including middleware services. There are three major components of instrumentinteroperability including physical, communication, and application/control layers. Participantsidentified the essential issues, current obstacles, and enabling technologies and standards,then came up with a series of short and long term solutions.The top three recommended actions, deemed achievable within 6 months of the release of thisreport are:A list of recommendations for enabling instrument interoperability should be put togetherand distributed to instrument developers.A recommendation for funding sources to achieve instrument interoperability should bedrafted. Funding should be provided (for example through NOPP or an IOOS request forproposals) to develop and demonstrate instrument interoperability technologies involvinginstrument manufacturers, observing system operators, and cyberinfrastructure groups.Program managers should be identified and made to understand that milestones for achievinginstrument interoperability include a) selection of a methodology for uniquely identifyingan instrument, b) development of a common protocol for automatic instrumentdiscovery, c) agreement on uniform methods for measurements, d) enablement of end usercontrolled power cycling, and e) implementation of a registry component for IDS and attributes.The top three recommended actions, deemed achievable within S years of the release of this reportare:An ocean observing interoperability standards body should be established that addresses standards for a) metadata, b) commands, c) protocols, d) processes, e) exclusivity, and f)naming authorities.[PDF contains 48 pages]

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The co-organized Alliance for Coastal Technologies (ACT) and National Data Buoy Center (NDBC)Workshop "Meteorological Buoy Sensors Workshop" convened in Solomons, Maryland, April 19to 21,2006, sponsored by the University of Maryland Center for Environmental Science (UMCES)Chesapeake Bay Laboratory (CBL), an ACT partner institution. Participants from various sectorsincluding resource managers and industry representatives collaborated to focus on technologies andsensors that measure the near surface variables of wind speed and direction, barometric pressure,humidity and air temperature. The vendor list was accordingly targeted at companies that producedthese types of sensors. The managers represented a cross section of federal, regional and academicmarine observing interests from around the country. Workshop discussions focused on the challengesassociated with making marine meteorological observations in general and problems that werespecific to a particular variable. Discussions also explored methods to mitigate these challengesthrough the adoption of best practices, improved technologies and increased standardization. Someof the key workshop outcomes and recommendations included:0cean.US should establish a committee devoted to observations. The committee wouldhave a key role in developing observing standards.The community should adopt the target cost, reliability and performance standards draftedfor a typical meteorological package to be used by a regional observing system.A forum should be established to allow users and manufacturers to share best practicesfor the employment of marine meteorological sensors. The ACT website would host theforum.Federal activities that evaluate meteorological sensors should make their results publiclyavailable.ACT should extend their evaluation process to include meteorological sensors.A follow on workshop should be conducted that covers the observing of meteorologicalvariables not addressed by this workshop. (pdf contains 18 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) convened a workshop on Evaluating Approaches and Technologies for Monitoring Organic Contaminants in the Aquatic Environment in Ann Arbor, MI on July 21-23, 2006. The primary objectives of this workshop were to: 1) identify the priority management information needs relative to organic contaminant loading; 2) explore themost appropriate approaches to estimating mass loading; and 3) evaluate the current status of thesensor technology. To meet these objectives, a mixture of leading research scientists, resourcemanagers, and industry representatives were brought together for a focused two-day workshop.The workshop featured four plenary talks followed by breakout sessions in which arranged groupsof participants where charged to respond to a series of focused discussion questions.At present, there are major concerns about the inadequacies in approaches and technologies forquantifying mass emissions and detection of organic contaminants for protecting municipal watersupplies and receiving waters. Managers use estimates of land-based contaminant loadings torivers, lakes, and oceans to assess relative risk among various contaminant sources, determinecompliance with regulatory standards, and define progress in source reduction. However, accuratelyquantifying contaminant loading remains a major challenge. Loading occurs over a range ofhydrologic conditions, requiring measurement technologies that can accommodate a broad rangeof ambient conditions. In addition, in situ chemical sensors that provide a means for acquiringcontinuous concentration measurements are still under development, particularly for organic contaminantsthat typically occur at low concentrations. Better approaches and strategies for estimatingcontaminant loading, including evaluations of both sampling design and sensor technologies,need to be identified. The following general recommendations were made in an effort to advancefuture organic contaminant monitoring:1. Improve the understanding of material balance in aquatic systems and the relationship betweenpotential surrogate measures (e.g., DOC, chlorophyll, particle size distribution) and target constituents.2. Develop continuous real-time sensors to be used by managers as screening measures and triggersfor more intensive monitoring.3. Pursue surrogate measures and indicators of organic pollutant contamination, such as CDOM,turbidity, or non-equilibrium partitioning.4. Develop continuous field-deployable sensors for PCBs, PAHs, pyrethroids, and emerging contaminantsof concern and develop strategies that couple sampling approaches with tools that incorporatesensor synergy (i.e., measure appropriate surrogates along with the dissolved organics toallow full mass emission estimation).[PDF contains 20 pages]

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: (pdf contains 23 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop "Making Oxygen MeasurementsRoutine Like Temperature" was convened in St. Petersburg, Florida, January 4th - 6th, 2006. Thisevent was sponsored by the University of South Florida (USF) College of Marine Science, anACT partner institution and co-hosted by the Ocean Research Interactive Observatory Networks(ORION). Participants from researcldacademia, resource management, industry, and engineeringsectors collaborated with the aim to foster ideas and information on how to make measuringdissolved oxygen a routine part of a coastal or open ocean observing system.Plans are in motion to develop large scale ocean observing systems as part of the US IntegratedOcean Observing System (100s; see http://ocean.us) and the NSF Ocean Observatory Initiative(001; see http://www.orionprogram.org/00I/default.hl). These systems will require biologicaland chemical sensors that can be deployed in large numbers, with high reliability, and forextended periods of time (years). It is also likely that the development cycle for new sensors issufficiently long enough that completely new instruments, which operate on novel principles,cannot be developed before these complex observing systems will be deployed. The most likelypath to development of robust, reliable, high endurance sensors in the near future is to movethe current generation of sensors to a much greater degree of readiness. The ACT OxygenSensor Technology Evaluation demonstrated two important facts that are related to the need forsensors. There is a suite of commercially available sensors that can, in some circumstances,generate high quality data; however, the evaluation also showed that none of the sensors were ableto generate high quality data in all circumstances for even one month time periods due tobiofouling issues.Many groups are attempting to use oxygen sensors in large observing programs; however, thereoften seems to be limited communication between these groups and they often do not have accessto sophisticated engineering resources. Instrument manufacturers also do not have sufficientresources to bring sensors, which are marketable, but of limited endurance or reliability, to ahigher state of readiness. The goal of this ACT/ORION Oxygen Sensor Workshop was to bringtogether a group of experienced oceanographers who are now deploying oxygen sensors inextended arrays along with a core of experienced and interested academic and industrialengineers, and manufacturers. The intended direction for this workshop was for this group toexchange information accumulated through a variety of sensor deployments, examine failuremechanisms and explore a variety of potential solutions to these problems. One anticipatedoutcome was for there to be focused recommendations to funding agencies on development needsand potential solutions for 02 sensors. (pdf contains 19 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop on Towed Vehicles: Undulating PlatformsAs Tools for Mapping Coastal Processes and Water Quality Assessment was convenedFebruary 5-7,2007 at The Embassy Suites Hotel, Seaside, California and sponsored by the ACT-PacificCoast partnership at the Moss Landing Marine Laboratories (MLML). The TUV workshopwas co-chaired by Richard Burt (Chelsea Technology Group) and Stewart Lamerdin (MLMLMarine Operations). Invited participants were selected to provide a uniform representation of theacademic researchers, private sector product developers, and existing and potential data productusers from the resource management community to enable development of broad consensus opinionson the application of TUV platforms in coastal resource assessment and management.The workshop was organized to address recognized limitations of point-based monitoring programs,which, while providing valuable data, are incapable of describing the spatial heterogeneityand the extent of features distributed in the bulk solution. This is particularly true as surveysapproach the coastal zone where tidal and estuarine influences result in spatially and temporallyheterogeneous water masses and entrained biological components. Aerial or satellite based remotesensing can provide an assessment of the aerial extent of plumes and blooms, yet provide no informationregarding the third dimension of these features. Towed vehicles offer a cost-effectivesolution to this problem by providing platforms, which can sample in the horizontal, vertical, andtime-based domains. Towed undulating vehicles (henceforth TUVs) represent useful platformsfor event-response characterization. This workshop reviewed the current status of towed vehicletechnology focusing on limitations of depth, data telemetry, instrument power demands, and shiprequirements in an attempt to identify means to incorporate such technology more routinely inmonitoring and event-response programs. Specifically, the participants were charged to addressthe following: (1) Summarize the state of the art in TUV technologies; (2) Identify how TUVplatforms are used and how they can assist coastal managers in fulfilling their regulatory and managementresponsibilities; (3) Identify barriers and challenges to the application of TUV technologiesin management and research activities, and (4) Recommend a series of community actions toovercome identified barriers and challenges.A series of plenary presentation were provided to enhance subsequent breakout discussions bythe participants. Dave Nelson (University of Rhode Island) provided extensive summaries andreal-world assessment of the operational features of a variety of TUV platforms available in theUNOLs scientific fleet. Dr. Burke Hales (Oregon State University) described the modification ofTUV to provide a novel sampling platform for high resolution mapping of chemical distributionsin near real time. Dr. Sonia Batten (Sir Alister Hardy Foundation for Ocean Sciences) providedan overview on the deployment of specialized towed vehicles equipped with rugged continuousplankton recorders on ships of opportunity to obtain long-term, basin wide surveys of zooplanktoncommunity structure, enhancing our understanding of trends in secondary production in the upperocean. [PDF contains 32 pages]

Description: NOAA

Description: The Alliance for Coastal Technologies (ACT) convened a Workshop on "Recent Developments in In Situ Nutrient Sensors: Applications and Future Directions" from 11-13 December, 2006. The workshop was held at the Georgia Coastal Center in Savannah, Georgia, with local coordination provided by the ACT partner at the Skidaway Institute of Oceanography (University System of Georgia). Since its formation in 2000, ACT partners have been conducting workshops on various sensor technologies and supporting infrastructure for sensor systems. This was the first workshop to revisit a topic area addressed previously by ACT.An earlier workshop on the "State of Technology in the Development and Application of Nutrient Sensors" was held in Savannah, Georgia from 10-12 March, 2003. Participants in the first workshop included representatives from management, industry, and research sectors. Among the topics addressed at the first workshop were characteristics of "ideal" in situ nutrient sensors, particularly with regard to applications in coastal marine waters.In contrast, the present workshop focused on the existing commercial solutions. The in situ nutrient sensor technologies that appear likely to remain the dominant commercial options for the next decade are reagent-based in situ auto-analyzers (or fluidics systems) and an optical approach (spectrophotometric measurement of nitrate). The number of available commercial systems has expanded since 2003, and community support for expanded application and further development of these technologies appears warranted. Application in coastal observing systems, including freshwater as well as estuarine and marine environments, was a focus of the present workshop.This included discussion of possible refinements for sustained deployments as part of integrated instrument packages and means to better promote broader use of nutrient sensors in observing system and management applications. The present workshop also made a number of specific recommendations concerning plans for a demonstration of in situ nutrient sensor technologies that ACT will be conducting in coordination with sensor manufacturers.[PDF contains 40 pages]

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) convened a workshop on "Wave Sensor Technologies" in St. Petersburg, Florida on March 7-9, 2007, hosted by the University of South Florida (USF) College of Marine Science, an ACT partner institution. The primary objectives of thisworkshop were to: 1) define the present state of wave measurement technologies, 2) identify the major impediments to their advancement, and 3) make strategic recommendations for future development and on the necessary steps to integrate wave measurement sensors into operationalcoastal ocean observing systems. The participants were from various sectors, including research scientists, technology developers and industry providers, and technology users, such as operational coastal managers and coastal decision makers.Waves consistently are ranked as a critical variable for numerous coastal issues, from maritime transportation to beach erosion to habitat restoration. For the purposes of this workshop, the participants focused on measuring "wind waves" (i.e., waves on the water surface, generated by thewind, restored by gravity and existing between approximately 3 and 30-second periods), although it was recognized that a wide range of both forced and free waves exist on and in the oceans. Also, whereas the workshop put emphasis on the nearshore coastal component of wave measurements, the participants also stressed the importance of open ocean surface waves measurement. Wave sensor technologies that are presently available for both environments include bottom-mounted pressure gauges, surface following buoys, wave staffs, acoustic Doppler current profilers, and shore-based remote sensing radar instruments.One of the recurring themes of workshop discussions was the dichotomous nature of wave data users. The two separate groups, open ocean wave data users and the nearshore/coastal wave data users, have different requirements. Generally, the user requirements increase both in spatial/temporal resolution and precision as one moves closer to shore. Most ocean going mariners areadequately satisfied with measurements of wave period and height and a wave general direction.However, most coastal and nearshore users require at least the first five Fourier parameters ("First 5"): wave energy and the first four directional Fourier coefficients. Furthermore, wave research scientists would like sensors capable of providing measurements beyond the first four Fourier coefficients. It was debated whether or not high precision wave observations in one location cantake the place of a less precise measurement at a different location. This could be accomplished by advancing wave models and using wave models to extend data to nearby areas. However, the consensus was that models are no substitution for in situ wave data.[PDF contains 26 pages]

Description: NOAA

Description: A three day workshop on turbidity measurements was held at the Hawaii Institute of MarineBiology from August 3 1 to September 2, 2005. The workshop was attended by 30 participantsfrom industry, coastal management agencies, and academic institutions. All groups recognizedcommon issues regarding the definition of turbidity, limitations of consistent calibration, and thelarge variety of instrumentation that nominally measure "turbidity." The major recommendations,in order of importance for the coastal monitoring community are listed below:1. The community of users in coastal ecosystems should tighten instrument designconfigurations to minimize inter-instrument variability, choosing a set of specificationsthat are best suited for coastal waters. The IS0 7027 design standard is not tight enough.Advice on these design criteria should be solicited through the ASTM as well as Federaland State regulatory agencies representing the majority of turbidity sensor end users.Parties interested in making turbidity measurements in coastal waters should developdesign specifications for these water types rather than relying on design standards madefor the analysis of drinking water.2. The coastal observing groups should assemble a community database relating output ofspecific sensors to different environmental parameters, so that the entire community ofusers can benefit from shared information. This would include an unbiased, parallel studyof different turbidity sensors, employing a variety of designs and configuration in thebroadest range of coastal environments.3. Turbidity should be used as a measure of relative change in water quality rather than anabsolute measure of water quality. Thus, this is a recommendation for managers todevelop their own local calibrations. See next recommendation.4. If the end user specifically wants to use a turbidity sensor to measure a specific waterquality parameter such as suspended particle concentration, then direct measurement ofthat water quality parameter is necessary to correlate with 'turbidity1 for a particularenvironment. These correlations, however, will be specific to the environment in whichthey are measured. This works because there are many environments in which watercomposition is relatively stable but varies in magnitude or concentration. (pdf contains 22 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: This Alliance for Coastal Technologies (ACT) workshop was convened to assess the availabilityand state of development of conductivity-temperature sensors that can meet the needs of coastalmonitoring and management communities. Rased on the discussion, there are presently a numberof commercial sensor options available, with a wide range of package configurations suitable fordeployment in a range of coastal environments. However, some of the central questions posedin the workshop planning documents were left somewhat unresolved. The workshop descriptionemphasized coastal management requirements and, in particular, whether less expensive, easilydeployed, lower-resolution instruments might serve many management needs. While several participantsexpressed interest in this class of conductivity-temperature sensors, based on input fromthe manufacturers, it is not clear that simply relaxing the present level of resolution of existing instrumentswill result in instruments of significantly lower unit cost. Conductivity-temperature sensorsare available near or under the $1,000 unit cost that was operationally defined at the workshopas a breakpoint for what might be considered to be a "low cost" sensor. For the manufacturers, akey consideration before undertaking the effort to develop lower cost sensors is whether there willbe a significant market. In terms of defining "low cost," it was also emphasized that the "life cyclecosts" for a given instrument must be considered (e.g., including personnel costs for deploymentand maintenance). An adequate market survey to demonstrate likely applications and a viablemarket for lower cost sensors is needed. Another topic for the workshop was the introductionto the proposed ACT verification for conductivity-temperature sensors. Following a summaryof the process as envisioned by ACT, initial feedback was solicited. Protocol development willbe pursued further in a workshop involving ACT personnel and conductivity-temperature sensormanufacturers.[PDF contains 28 pages]

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The use of self-contained, low-maintenance sensor systems installed on commercial vessels isbecoming an important monitoring and scientific tool in many regions around the world. Thesesystems integrate data from meteorological and water quality sensors with GPS data into a datastream that is automatically transferred from ship to shore. To begin linking some of this developingexpertise, the Alliance for Coastal Technologies (ACT) and the European Coastal and OceanObserving Technology (ECOOT) organized a workshop on this topic in Southampton, UnitedKingdom, October 10-12, 2006. The participants included technology users, technology developers,and shipping representatives. They collaborated to identify sensors currently employed onintegrated systems, users of this data, limitations associated with these systems, and ways to overcomethese limitations. The group also identified additional technologies that could be employedon future systems and examined whether standard architectures and data protocols for integratedsystems should be established.Participants at the workshop defined 17 different parameters currently being measured by integratedsystems. They identified that diverse user groups utilize information from these systemsfrom resource management agencies, such as the Environmental Protection Agency (EPA), to localtourism groups and educational organizations. Among the limitations identified were instrumentcompatibility and interoperability, data quality control and quality assurance, and sensor calibrationandlor maintenance frequency. Standardization of these integrated systems was viewed to beboth advantageous and disadvantageous; while participants believed that standardization could bebeneficial on many levels, they also felt that users may be hesitant to purchase a suite of instrumentsfrom a single manufacturer; and that a "plug and play" system including sensors from multiplemanufactures may be difficult to achieve.A priority recommendation and conclusion for the general integrated sensor system communitywas to provide vessel operators with real-time access to relevant data (e.g., ambient temperatureand salinity to increase efficiency of water treatment systems and meteorological data for increasedvessel safety and operating efficiency) for broader system value. Simplified data displaysare also required for education and public outreach/awareness. Other key recommendations wereto encourage the use of integrated sensor packages within observing systems such as 100s andEuroGOOS, identify additional customers of sensor system data, and publish results of previouswork in peer-reviewed journals to increase agency and scientific awareness and confidence in thetechnology.Priority recommendations and conclusions for ACT entailed highlighting the value of integratedsensor systems for vessels of opportunity through articles in the popular press, and marine science. [PDF contains 28 pages]

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop entitled "Technologies for MeasuringCurrents in Coastal Environments" was held in Portland, Maine, October 26-28, 2005, withsponsorship by the Gulf of Maine Ocean Observing System (GoMOOS), an ACT partnerorganization. The primary goals of the event were to summarize recent trends in nearshoreresearch and management applications for current meter technologies, identify how currentmeters can assist coastal managers to fulfill their regulatory and management objectives, and torecommend actions to overcome barriers to use of the technologies. The workshop was attendedby 25 participants representing state and federal environmental management agencies,manufacturers of current meter technologies, and researchers from academic institutions andprivate industry.Common themes that were discussed during the workshop included 1) advantages and limitationsof existing current measuring equipment, 2) reliability and ease of use with each instrument type,3) data decoding and interpretation procedures, and 4) mechanisms to facilitate better training andguidance to a broad user group. Seven key recommendations, which were ranked in order ofimportance during the last day of the workshop are listed below.1. Forums should be developed to facilitate the exchange of information among users andindustry:a) On-line forums that not only provide information on specific instruments andtechnologies, but also provide an avenue for the exchange of user experiences withvarious instruments (i.e. problems encountered, cautions, tips, advantages, etc). (seeReferences for manufacturer websites with links to application and technical forums atend of report)b) Regional training/meetings for operational managers to exchange ideas on methods formeasuring currents and evaluating data.c) Organize mini-meetings or tutorial sessions within larger conference venues.2. A committee of major stakeholders should be convened to develop common standards(similar to the Institute of Electrical and Electronics Engineers (IEEE) committee) thatenable users to switch sensors without losing software or display capabilities. (pdf contains 28 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) held a Workshop on Sensor Technology forAssessing Groundwater-Surface Water Interactions in the Coastal Zone on March 7 to 9,2005 inSavannah, GA. The main goal of the workshop was to summarize the general parameters, whichhave been found to be useful in assessing groundwater-surface water (GW-SW) interactions in thecoastal zone. The workshop participants (Appendix I) were specifically charged with identifyingthe types of sensor systems, if any, that have been used to obtain time-series data and to makeknown which parameters may be the most amenable to the development/application of sensortechnology. The group consisted of researchers, industry representatives, and environmentalmanagers.Four general recommendations were made:1. Educate coastal managers and agencies on the importance of GW-SW interactions,keeping in mind that regulatory agencies are driven by a different set of rules thanresearchers: the focus is on understanding the significance of the problem and providingsolutions. ACT could facilitate this process in two ways. First, given that the researchliterature on this subject is fairly diffuse, ACT could provide links from its web site to factsheets or other literature. Second, ACT could organize a focused meeting for managersand/or agency groups.Encourage development of primary tools for quantifying flow. The most promisingtechnology in this respect is flow meters designed for flux chambers, mainly because theyshould be simple to use and can be made relatively inexpensively. However, it should bekept in mind that they provide only point measurements and several would need to bedeployed as a network in order to obtain reliable flow estimates. For evaluating systemwide GW-SW interactions, tools that integrate the signal over large areas would berequired. Suggestions include a user-friendly hydrogeologic models, keeping in mind thatfreshwater flow is not the entire story, or continuous radon monitors. Though the latterwould be slightly more difficult to use in terms of background knowledge, such aninstrument would be low power and easy to operate and maintain. ACT could facilitatethis recommendation by identifying funding opportunities on its web site and/orperforming evaluations of existing technologies that could be summarized on the web site. (pdf contains 18 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop on Optical Remote Sensing of CoastalHabitats was convened January 9-11, 2006 at Moss Landing Marine Laboratories in MossLanding, California, sponsored by the ACT West Coast regional partnership comprised of theMoss Landing Marine Laboratories (MLML) and the Monterey Bay Aquarium Research Institute(MBARI). The "Optical Remote Sensing of Coastal Habitats" (ORS) Workshop completesACT'S Remote Sensing Technology series by building upon the success of ACT'S West CoastRegional Partner Workshop "Acoustic Remote Sensing Technologies for Coastal Imaging andResource Assessment" (ACT 04-07). Drs. Paul Bissett of the Florida Environmental ResearchInstitute (FERI) and Scott McClean of Satlantic, Inc. were the ORS workshop co-chairs. Invitedparticipants were selected to provide a uniform representation of the academic researchers, privatesector product developers, and existing and potential data product users from the resource managementcommunity to enable development of broad consensus opinions on the role of ORS technologiesin coastal resource assessment and management.The workshop was organized to examine the current state of multi- and hyper-spectral imagingtechnologies with the intent to assess the current limits on their routine application for habitat classificationand resource monitoring of coastal watersheds, nearshore shallow water environments,and adjacent optically deep waters. Breakout discussions focused on the capabilities, advantages,and limitations of the different technologies (e.g., spectral & spatial resolution), as well as practicalissues related to instrument and platform availability, reliability, hardware, software, and technicalskill levels required to exploit the data products generated by these instruments. Specifically,the participants were charged to address the following: (1) Identify the types of ORS data productscurrently used for coastal resource assessment and how they can assist coastal managers in fulfillingtheir regulatory and management responsibilities; (2) Identify barriers and challenges to theapplication of ORS technologies in management and research activities; (3) Recommend a seriesof community actions to overcome identified barriers and challenges.Plenary presentations by Drs. Curtiss 0. Davis (Oregon State University) and Stephan Lataille(ITRES Research, Ltd.) provided background summaries on the varieties of ORS technologiesavailable, deployment platform options, and tradeoffs for application of ORS data products withspecific applications to the assessment of coastal zone water quality and habitat characterization.Dr. Jim Aiken (CASIX) described how multiscale ground-truth measurements were essential fordeveloping robust assessment of modeled biogeochemical interpretations derived from opticallybased earth observation data sets. While continuing improvements in sensor spectral resolution,signal to noise and dynamic range coupled with sensor-integrated GPS, improved processing algorithmsfor georectification, and atmospheric correction have made ORS data products invaluablesynoptic tools for oceanographic research, their adoption as management tools has lagged. SethBlitch (Apalachicola National Estuarine Research Reserve) described the obvious needs for, yetsubstantial challenges hindering the adoption of advanced spectroscopic imaging data productsto supplement the current dominance of digital ortho-quad imagery by the resource managementcommunity, especially when they impinge on regulatory issues. (pdf contains 32 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop on Trace Metal Sensors for CoastalMonitoring was convened April 11-13, 2005 at the Embassy Suites in Seaside, California withpartnership from Moss Landing Marine Laboratories (MLML) and the Monterey Bay AquariumResearch Institute (MBARI).Trace metals play many important roles in marine ecosystems. Due to their extreme toxicity, theeffects of copper, cadmium and certain organo-metallinc compounds (such as tributyltin andmethylmercury) have received much attention. Lately, the sublethal effects of metals onphytoplankton biochemistry, and in some cases the expression of neurotoxins (Domoic acid),have been shown to be important environmental forcing functions determining the compositionand gene expression in some groups. More recently the role of iron in controlling phytoplanktongrowth has led to an understanding of trace metal limitation in coastal systems. Although metalsplay an important role at many different levels, few technologies exist to provide rapid assessmentof metal concentrations or metal speciation in the coastal zone where metal-induced toxicity orpotential stimulation of harmful algal blooms, can have major economic impacts. This workshopfocused on the state of on-site and in situ trace element detection technologies, in terms of whatis currently working well and what is needed to effectively inform coastal zone managers, as wellas guide adaptive scientific sampling of the coastal zone. Specifically the goals of this workshopwere to: 1) summarize current regional requirements and future targets for metal monitoring infreshwater, estuarine and coastal environments; 2) evaluate the current status of metal sensors andpossibilities for leveraging emerging technologies for expanding detection limits and targetelements; and 3) help identify critical steps needed for and limits to operational deployment ofmetal sensors as part of routine water quality monitoring efforts.Following a series of breakout group discussions and overview talks on metal monitoringregulatory issues, analytical techniques and market requirements, workshop participants madeseveral recommendations for steps needed to foster development of in situ metal monitoringcapacities:1. Increase scientific and public awareness of metals of environmental and biologicalconcern and their impacts in aquatic environments. Inform scientific and publiccommunities regarding actual levels of trace metals in natural and perturbed systems.2. Identify multiple use applications (e.g., industrial waste steam and drinking water qualitymonitoring) to support investments in metal sensor development. (pdf contains 27 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The Alliance for Coastal Technologies (ACT) Workshop "Applications of in situ Fluorometers inNearshore Waters" was held in Cape Elizabeth, Maine, February 2-4,2005, with sponsorship bythe Gulf of Maine Ocean Observing System (GoMOOS), one of the ACT partner organization.The purpose of the workshop was to explore recent trends in fluorometry as it relates to resourcemanagement applications in nearshore environments. Participants included representatives fromstate and federal environmental management agencies as well as research institutions, many ofwhom are currently using this technology in their research and management applications.Manufacturers and developers of fluorometric measuring systems also attended the meeting.The Workshop attendees discussed the historical and present uses of fluorometry technology andidentified the great potential for its use by coastal managers to fulfill their regulatory andmanagement objectives. Participants also identified some of the challenges associated with thecorrect use of Fluorometers to estimate biomass and the rate of primary productivity. TheWorkshop concluded that in order to expand the existing use of fluorometers in both academicand resource management disciplines, several issues concerning data collection, instrumentcalibration, and data interpretation needed to be addressed. Participants identified twelverecommendations, the top five of which are listed below:Recommendations1) Develop a "Guide" that describes the most important aspects of fluorescencemeasurements. This guide should be written by an expert party, with both research andindustry input, and should be distributed by all manufacturers with theirinstrumentation. The guide should also be made available on the ACT website as wellas those of other relevant organizations. The guide should include discussions on thefollowing topics:The benefits of using fluorometers in research and resource managementapplications;What fluorometers can and cannot provide in terms of measurements;The necessary assumptions required before applying fluorometry;Characterization and calibration of fluorometers; (pdf contains 32 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: Future coastal management practices require that a holistic, ecosystem management approach beadopted. Coastal ecosystems, however, present a variety of specific and unique challengesrelative to open ocean systems. In particular, interactions with the seabed significantly influencethe coastal ecosystem. Observing technologies must be developed and employed to incorporateseafloor interactions, processes and habitat diversity into research and management activities.An ACT Workshop on Seabed Sensor Technology was held February 1-3, 2006 in Savannah,Georgia, to summarize the current state of sensor technologies applicable to examining andmonitoring the coastal seabed, including the near-bed benthic boundary layer and surfacesediment layer. Workshop participants were specifically charged to identify current sensors inuse, recommend improvements to these systems and to identify areas for future development andactivities that would advance the use of sensor technology in the observation, monitoring andmanagement of the coastal benthic environment. (pdf contains 23 pages)

Description: NOAA

Description: Alliance for Coastal Technologies, CBL/UMCES

Description: The comment and response concerning the report of oxidation of methane to methanol by water (Reports, 5 May 2017, p. 523) do not fully capture the implications of thermodynamic limitations. A nonisothermal process in which each cycle requires a large temperature swing and permits only substoichiometric methane conversion surely could not be carried out on any practical scale.

Description: Labinger argues that stepwise reaction of methane with water to produce methanol and hydrogen will never be commercially feasible because of its substoichiometric basis with respect to the active site and the requirement of a large temperature swing. This comment is not touching any new ground, beyond describing the thermodynamic feasibility, thermal cycling, and the role of water as discussed previously. Most important, it does not have a solid numerical basis.

Description: Vinyl carbocations have been the subject of extensive experimental and theoretical studies over the past five decades. Despite this long history in chemistry, the utility of vinyl cations in chemical synthesis has been limited, with most reactivity studies focusing on solvolysis reactions or intramolecular processes. Here we report synthetic and mechanistic studies of vinyl cations generated through silylium–weakly coordinating anion catalysis. We find that these reactive intermediates undergo mild intermolecular carbon-carbon bond–forming reactions, including carbon-hydrogen (C–H) insertion into unactivated sp 3 C–H bonds and reductive Friedel-Crafts reactions with arenes. Moreover, we conducted computational studies of these alkane C–H functionalization reactions and discovered that they proceed through nonclassical, ambimodal transition structures. This reaction manifold provides a framework for the catalytic functionalization of hydrocarbons using simple ketone derivatives.

Description: It is commonly assumed that recognition and discrimination of chirality, both in nature and in artificial systems, depend solely on spatial effects. However, recent studies have suggested that charge redistribution in chiral molecules manifests an enantiospecific preference in electron spin orientation. We therefore reasoned that the induced spin polarization may affect enantiorecognition through exchange interactions. Here we show experimentally that the interaction of chiral molecules with a perpendicularly magnetized substrate is enantiospecific. Thus, one enantiomer adsorbs preferentially when the magnetic dipole is pointing up, whereas the other adsorbs faster for the opposite alignment of the magnetization. The interaction is not controlled by the magnetic field per se, but rather by the electron spin orientations, and opens prospects for a distinct approach to enantiomeric separations.

Description: Theory has established the importance of geometric phase (GP) effects in the adiabatic dynamics of molecular systems with a conical intersection connecting the ground- and excited-state potential energy surfaces, but direct observation of their manifestation in chemical reactions remains a major challenge. Here, we report a high-resolution crossed molecular beams study of the H + HD -〉 H 2 + D reaction at a collision energy slightly above the conical intersection. Velocity map ion imaging revealed fast angular oscillations in product quantum state–resolved differential cross sections in the forward scattering direction for H 2 products at specific rovibrational levels. The experimental results agree with adiabatic quantum dynamical calculations only when the GP effect is included.

Description: The chemistry of the carbonyl group is essential to modern organic synthesis. The preparation of substituted, enantioenriched 1,3- or 1,5-dicarbonyls is well developed, as their disconnection naturally follows from the intrinsic polarity of the carbonyl group. By contrast, a general enantioselective access to quaternary stereocenters in acyclic 1,4-dicarbonyl systems remains an unresolved problem, despite the tremendous importance of 2,3-substituted 1,4-dicarbonyl motifs in natural products and drug scaffolds. Here we present a broad enantioselective and stereodivergent strategy to access acyclic, polysubstituted 1,4-dicarbonyls via acid-catalyzed [3,3]-sulfonium rearrangement starting from vinyl sulfoxides and ynamides. The stereochemistry at sulfur governs the absolute sense of chiral induction, whereas the double bond geometry dictates the relative configuration of the final products.

Description: Polyamide thickness and roughness have been identified as critical properties that affect thin-film composite membrane performance for reverse osmosis. Conventional formation methodologies lack the ability to control these properties independently with high resolution or precision. An additive approach is presented that uses electrospraying to deposit monomers directly onto a substrate, where they react to form polyamide. The small droplet size coupled with low monomer concentrations result in polyamide films that are smoother and thinner than conventional polyamides, while the additive nature of the approach allows for control of thickness and roughness. Polyamide films are formed with a thickness that is controllable down to 4-nanometer increments and a roughness as low as 2 nanometers while still exhibiting good permselectivity relative to a commercial benchmarking membrane.

Description: With the recent soaring production of natural gas, the use of methane and other light hydrocarbon feedstocks as starting materials in synthetic transformations is becoming increasingly economically attractive, although it remains chemically challenging. We report the development of photocatalytic C–H amination, alkylation, and arylation of methane, ethane, and higher alkanes under visible light irradiation at ambient temperature. High catalytic efficiency (turnover numbers up to 2900 for methane and 9700 for ethane) and selectivity were achieved using abundant, inexpensive cerium salts as photocatalysts. Ligand-to-metal charge transfer excitation generated alkoxy radicals from simple alcohols that in turn acted as hydrogen atom transfer catalysts. The mixed-phase gas/liquid reaction was adapted to continuous flow, enabling the efficient use of gaseous feedstocks in scalable photocatalytic transformations.

Description: Intrigued by the potential of nanoscale machines, scientists have long attempted to control molecular motion. We monitored the individual 0.7-nanometer steps of a single molecular hopper as it moved in an electric field along a track in a nanopore controlled by a chemical ratchet. The hopper demonstrated characteristics desired in a moving molecule: defined start and end points, processivity, no chemical fuel requirement, directional motion, and external control. The hopper was readily functionalized to carry cargos. For example, a DNA molecule could be ratcheted along the track in either direction, a prerequisite for nanopore sequencing.

Description: Zeolitic imidazolate framework (ZIF) membranes are emerging as a promising energy-efficient separation technology. However, their reliable and scalable manufacturing remains a challenge. We demonstrate the fabrication of ZIF nanocomposite membranes by means of an all-vapor-phase processing method based on atomic layer deposition (ALD) of ZnO in a porous support followed by ligand-vapor treatment. After ALD, the obtained nanocomposite exhibits low flux and is not selective, whereas after ligand-vapor (2-methylimidazole) treatment, it is partially transformed to ZIF and shows stable performance with high mixture separation factor for propylene over propane (an energy-intensive high-volume separation) and high propylene flux. Membrane synthesis through ligand-induced permselectivation of a nonselective and impermeable deposit is shown to be simple and highly reproducible and holds promise for scalability.

Description: Insects are among the most agile natural flyers. Hypotheses on their flight control cannot always be validated by experiments with animals or tethered robots. To this end, we developed a programmable and agile autonomous free-flying robot controlled through bio-inspired motion changes of its flapping wings. Despite being 55 times the size of a fruit fly, the robot can accurately mimic the rapid escape maneuvers of flies, including a correcting yaw rotation toward the escape heading. Because the robot’s yaw control was turned off, we showed that these yaw rotations result from passive, translation-induced aerodynamic coupling between the yaw torque and the roll and pitch torques produced throughout the maneuver. The robot enables new methods for studying animal flight, and its flight characteristics allow for real-world flight missions.

Description: Phosphorothioate nucleotides have emerged as powerful pharmacological substitutes of their native phosphodiester analogs with important translational applications in antisense oligonucleotide (ASO) therapeutics and cyclic dinucleotide (CDN) synthesis. Stereocontrolled installation of this chiral motif has long been hampered by the systemic use of phosphorus(III) [P(III)]–based reagent systems as the sole practical means of oligonucleotide assembly. A fundamentally different approach is described herein: the invention of a P(V)-based reagent platform for programmable, traceless, diastereoselective phosphorus-sulfur incorporation. The power of this reagent system is demonstrated through the robust and stereocontrolled synthesis of various nucleotidic architectures, including ASOs and CDNs, via an efficient, inexpensive, and operationally simple protocol.

Description: Here we report an anomalous porous molecular crystal built of C–H···N-bonded double-layered roof-floor components and wall components of a segregatively interdigitated architecture. This complicated porous structure consists of only one type of fully aromatic multijoint molecule carrying three identical dipyridylphenyl wedges. Despite its high symmetry, this molecule accomplishes difficult tasks by using two of its three wedges for roof-floor formation and using its other wedge for wall formation. Although a C–H···N bond is extremely labile, the porous crystal maintains its porosity until thermal breakdown of the C–H···N bonds at 202°C occurs, affording a nonporous polymorph. Though this nonporous crystal survives even at 325°C, it can retrieve the parent porosity under acetonitrile vapor. These findings show how one can translate simplicity into ultrahigh complexity.

Description: Some of the simplest and most powerful carbon-carbon bond forming strategies take advantage of readily accessible ubiquitous motifs: carbonyls and olefins. Here we report a fundamentally distinct mode of reactivity between carbonyls and olefins that differs from established acid-catalyzed carbonyl-ene, Prins, and carbonyl-olefin metathesis reaction paths. A range of epsilon, zeta-unsaturated ketones undergo Brønsted acid–catalyzed intramolecular cyclization to provide tetrahydrofluorene products via the formation of two new carbon-carbon bonds. Theoretical calculations and accompanying mechanistic studies suggest that this carbocyclization reaction proceeds through the intermediacy of a transient oxetane formed by oxygen atom transfer. The complex polycyclic frameworks in this product class appear as common substructures in organic materials, bioactive natural products, and recently developed pharmaceuticals.

Description: Alkene aminoarylation with a single, bifunctional reagent is a concise synthetic strategy. We report a catalytic protocol for the addition of arylsulfonylacetamides across electron-rich alkenes with complete anti-Markovnikov regioselectivity and excellent diastereoselectivity to provide 2,2-diarylethylamines. In this process, single-electron alkene oxidation enables carbon-nitrogen bond formation to provide a key benzylic radical poised for a Smiles-Truce 1,5-aryl shift. This reaction is redox-neutral, exhibits broad functional group compatibility, and occurs at room temperature with loss of sulfur dioxide. As this process is driven by visible light, uses readily available starting materials, and demonstrates convergent synthesis, it is well suited for use in a variety of synthetic endeavors.

Description: Photocatalysis based on optically active, "plasmonic" metal nanoparticles has emerged as a promising approach to facilitate light-driven chemical conversions under far milder conditions than thermal catalysis. However, an understanding of the relation between thermal and electronic excitations has been lacking. We report the substantial light-induced reduction of the thermal activation barrier for ammonia decomposition on a plasmonic photocatalyst. We introduce the concept of a light-dependent activation barrier to account for the effect of light illumination on electronic and thermal excitations in a single unified picture. This framework provides insight into the specific role of hot carriers in plasmon-mediated photochemistry, which is critically important for designing energy-efficient plasmonic photocatalysts.

Description: Single-electron reduction of a carbonyl to a ketyl enables access to a polarity-reversed platform of reactivity for this cornerstone functional group. However, the synthetic utility of the ketyl radical is hindered by the strong reductants necessary for its generation, which also limit its reactivity to net reductive mechanisms. We report a strategy for net redox-neutral generation and reaction of ketyl radicals. The in situ conversion of aldehydes to α-acetoxy iodides lowers their reduction potential by more than 1 volt, allowing for milder access to the corresponding ketyl radicals and an oxidative termination event. Upon subjecting these iodides to a dimanganese decacarbonyl precatalyst and visible light irradiation, an atom transfer radical addition (ATRA) mechanism affords a broad scope of vinyl iodide products with high Z -selectivity.

Description: Reactions that form a product with the same reactive functionality as that of one of the starting compounds frequently end in oligomerization. As a salient example, selective aldol coupling of the smallest, though arguably most useful, enolizable aldehyde, acetaldehyde, with just one partner substrate has proven to be extremely challenging. Here, we report a highly enantioselective Mukaiyama aldol reaction with the simple triethylsilyl (TES) and tert -butyldimethylsilyl (TBS) enolates of acetaldehyde and various aliphatic and aromatic acceptor aldehydes. The reaction is catalyzed by recently developed, strongly acidic imidodiphosphorimidates (IDPi), which, like enzymes, display a confined active site but, like small-molecule catalysts, have a broad substrate scope. The process is scalable, fast, efficient (0.5 to 1.5 mole % catalyst loading), and greatly simplifies access to highly valuable silylated acetaldehyde aldols.

Description: Single-molecule magnets (SMMs) containing only one metal center may represent the lower size limit for molecule-based magnetic information storage materials. Their current drawback is that all SMMs require liquid-helium cooling to show magnetic memory effects. We now report a chemical strategy to access the dysprosium metallocene cation [(Cp i Pr5 )Dy(Cp*)] + (Cp i Pr5 , penta-iso-propylcyclopentadienyl; Cp *, pentamethylcyclopentadienyl), which displays magnetic hysteresis above liquid-nitrogen temperatures. An effective energy barrier to reversal of the magnetization of U eff = 1541 wave number is also measured. The magnetic blocking temperature of T B = 80 kelvin for this cation overcomes an essential barrier toward the development of nanomagnet devices that function at practical temperatures.

Description: The development of highly reactive and stereoselective catalytic systems is required not only to improve existing synthetic methods but also to invent distinct chemical reactions. Herein, a homogenized combination of nickel-based Lewis acid–surfactant-combined catalysts and single-walled carbon nanotubes is shown to exhibit substantial activity in water. In addition to the enhanced reactivity, stereoselective performance and long-term stability were demonstrated in asymmetric conjugate addition reactions of aldoximes to furnish chiral nitrones in high yields with excellent selectivities. The practical and straightforward application of the designed catalysts in water provides an expedient, environmentally benign, and highly efficient pathway to access optically active compounds.

Description: Exploration of intermediates that enable chemoselective cycloaddition reactions and expeditious construction of fused- or bridged-ring systems is a continuous challenge for organic synthesis. As an intermediate of interest, the oxyallyl cation has been harnessed to synthesize architectures containing seven-membered rings via (4+3) cycloaddition. However, its potential to access five-membered skeletons is underdeveloped, largely due to the thermally forbidden (3+2) pathway. Here, the combination of a tailored precursor and a Pd(0) catalyst generates a Pd-oxyallyl intermediate that cyclizes with conjugated dienes to produce a diverse array of tetrahydrofuran skeletons. The cycloaddition overrides conventional (4+3) selectivity by proceeding through a stepwise pathway involving a Pd-allyl transfer and ring closure sequence. Subsequent treatment of the (3+2) adducts with a palladium catalyst converts the heterocycles to the carbocyclic cyclopentanones.

Description: Understanding the practical limitations of chemical reactions is critically important for efficiently planning the synthesis of compounds in pharmaceutical, agrochemical, and specialty chemical research and development. However, literature reports of the scope of new reactions are often cursory and biased toward successful results, severely limiting the ability to predict reaction outcomes for untested substrates. We herein illustrate strategies for carrying out large-scale surveys of chemical reactivity by using a material-sparing nanomole-scale automated synthesis platform with greatly expanded synthetic scope combined with ultrahigh-throughput matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS).

Description: Researchers around the world have observed the formation of molecularly ordered structures of unknown origin on the surface of titanium dioxide (TiO 2 ) photocatalysts exposed to air and solution. Using a combination of atomic-scale microscopy and spectroscopy, we show that TiO 2 selectively adsorbs atmospheric carboxylic acids that are typically present in parts-per-billion concentrations while effectively repelling other adsorbates, such as alcohols, that are present in much higher concentrations. The high affinity of the surface for carboxylic acids is attributed to their bidentate binding. These self-assembled monolayers have the unusual property of being both hydrophobic and highly water-soluble, which may contribute to the self-cleaning properties of TiO 2 . This finding is relevant to TiO 2 photocatalysis, because the self-assembled carboxylate monolayers block the undercoordinated surface cation sites typically implicated in photocatalysis.

Description: The alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) typically engage in chemical bonding as classical main-group elements through their n s and n p valence orbitals, where n is the principal quantum number. Here we report the isolation and spectroscopic characterization of eight-coordinate carbonyl complexes M(CO) 8 (where M = Ca, Sr, or Ba) in a low-temperature neon matrix. Analysis of the electronic structure of these cubic O h -symmetric complexes reveals that the metal–carbon monoxide (CO) bonds arise mainly from [M(d )] -〉 (CO) 8 backdonation, which explains the strong observed red shift of the C-O stretching frequencies. The corresponding radical cation complexes were also prepared in gas phase and characterized by mass-selected infrared photodissociation spectroscopy, confirming adherence to the 18-electron rule more conventionally associated with transition metal chemistry.

Description: Mystery surrounds the transition from gas-phase hydrocarbon precursors to terrestrial soot and interstellar dust, which are carbonaceous particles formed under similar conditions. Although polycyclic aromatic hydrocarbons (PAHs) are known precursors to high-temperature carbonaceous-particle formation, the molecular pathways that initiate particle formation are unknown. We present experimental and theoretical evidence for rapid molecular clustering–reaction pathways involving radicals with extended conjugation. These radicals react with other hydrocarbon species to form covalently bound complexes that promote further growth and clustering by regenerating resonance-stabilized radicals through low-barrier hydrogen-abstraction and hydrogen-ejection reactions. Such radical–chain reaction pathways may lead to covalently bound clusters of PAHs and other hydrocarbons that would otherwise be too small to condense at high temperatures, thus providing the key mechanistic steps for rapid particle formation and surface growth by hydrocarbon chemisorption.

Description: Basic heteroarenes are a ubiquitous feature of pharmaceuticals and bioactive molecules, and Minisci-type additions of radical nucleophiles are a leading method for their elaboration. Despite many Minisci-type protocols that result in the formation of stereocenters, exerting control over the absolute stereochemistry at these centers remains an unmet challenge. We report a process for addition of prochiral radicals, generated from amino acid derivatives, to pyridines and quinolines. Our method offers excellent control of both enantioselectivity and regioselectivity. An enantiopure chiral Brønsted acid catalyst serves both to activate the substrate and induce asymmetry, while an iridium photocatalyst mediates the required electron transfer processes. We anticipate that this method will expedite access to enantioenriched small-molecule building blocks bearing versatile basic heterocycles.

Description: Primary amines are essential constituents of biologically active molecules and versatile intermediates in the synthesis of drugs and agrochemicals. However, their preparation from easily accessible alkenes remains challenging. Here, we report a general strategy to access primary amines from alkenes through an operationally simple iron-catalyzed aminochlorination reaction. A stable hydroxylamine derivative and benign sodium chloride act as the respective nitrogen and chlorine sources. The reaction proceeds at room temperature under air; tolerates a large scope of aliphatic and conjugated alkenes, including densely functionalized substrates; and provides excellent anti-Markovnikov regioselectivity with respect to the amino group. The reactivity of the 2-chloroalkylamine products, an understudied class of amphoteric molecules, enables facile access to linear or branched aliphatic amines, aziridines, aminonitriles, azido amines, and homoallylic amines.

Description: Despite the enormous potential for the use of stereospecific cross-coupling reactions to rationally manipulate the three-dimensional structure of organic molecules, the factors that control the transfer of stereochemistry in these reactions remain poorly understood. Here we report a mechanistic and synthetic investigation into the use of enantioenriched alkylboron nucleophiles in stereospecific Pd-catalyzed Suzuki cross-coupling reactions. By developing a suite of molecular descriptors of phosphine ligands, we could apply predictive statistical models to select or design distinct ligands that respectively promoted stereoinvertive and stereoretentive cross-coupling reactions. Stereodefined branched structures were thereby accessed through the predictable manipulation of absolute stereochemistry, and a general model for the mechanism of alkylboron transmetallation was proposed.

Description: Heterobiaryls composed of pyridine and diazine rings are key components of pharmaceuticals and are often central to pharmacological function. We present an alternative approach to metal-catalyzed cross-coupling to make heterobiaryls using contractive phosphorus C–C couplings, also termed phosphorus ligand coupling reactions. The process starts by regioselective phosphorus substitution of the C–H bonds para to nitrogen in two successive heterocycles; ligand coupling is then triggered via acidic alcohol solutions to form the heterobiaryl bond. Mechanistic studies imply that ligand coupling is an asynchronous process involving migration of one heterocycle to the ipso position of the other around a central pentacoordinate P(V) atom. The strategy can be applied to complex drug-like molecules containing multiple reactive sites and polar functional groups, and also enables convergent coupling of drug fragments and late-stage heteroarylation of pharmaceuticals.

Description: Conical intersections play a critical role in excited-state dynamics of polyatomic molecules because they govern the reaction pathways of many nonadiabatic processes. However, ultrafast probes have lacked sufficient spatial resolution to image wave-packet trajectories through these intersections directly. Here, we present the simultaneous experimental characterization of one-photon and two-photon excitation channels in isolated CF 3 I molecules using ultrafast gas-phase electron diffraction. In the two-photon channel, we have mapped out the real-space trajectories of a coherent nuclear wave packet, which bifurcates onto two potential energy surfaces when passing through a conical intersection. In the one-photon channel, we have resolved excitation of both the umbrella and the breathing vibrational modes in the CF 3 fragment in multiple nuclear dimensions. These findings benchmark and validate ab initio nonadiabatic dynamics calculations.

Description: Common anionic nucleophiles such as those derived from inorganic salts have not been used for enantioselective catalysis because of their insolubility. Here, we report that merging hydrogen bonding and phase-transfer catalysis provides an effective mode of activation for nucleophiles that are insoluble in organic solvents. This catalytic manifold relies on hydrogen bonding complexation to render nucleophiles soluble and reactive, while simultaneously inducing asymmetry in the ensuing transformation. We demonstrate the concept using a chiral bis-urea catalyst to form a tridentate hydrogen bonding complex with fluoride from its cesium salt, thereby enabling highly efficient enantioselective ring opening of episulfonium ion. This fluorination method is synthetically valuable considering the scarcity of alternative protocols and points the way to wider application of the catalytic approach with diverse anionic nucleophiles.

Description: Carbon dioxide (CO 2 ) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO 2 to ethylene with 70% faradaic efficiency at a potential of –0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO 2 reduction and carbon monoxide (CO)–CO coupling activation energy barriers; as a result, onset of ethylene evolution at –0.165 volts versus an RHE in 10 molar potassium hydroxide occurs almost simultaneously with CO production. Operational stability was enhanced via the introduction of a polymer-based gas diffusion layer that sandwiches the reaction interface between separate hydrophobic and conductive supports, providing constant ethylene selectivity for an initial 150 operating hours.

Description: White phosphorus, generated in the legacy thermal process for phosphate rock upgrading, has long been the key industrial intermediate for the synthesis of phosphorus-containing chemicals, including herbicides, flame-retardants, catalyst ligands, battery electrolytes, pharmaceuticals, and detergents. In contrast, phosphate fertilizers are made on a much larger scale from phosphoric acid, obtained by treating phosphate rock with sulfuric acid. Dehydration of phosphoric acid using sodium chloride gives trimetaphosphate, and here we report that trichlorosilane, primarily used for the production of high-purity silicon, reduces trimetaphosphate to the previously unknown bis(trichlorosilyl)phosphide anion. This anion offers an entry point to value-added organophosphorus chemicals such as primary and secondary alkyl phosphines, and thus to organophosphinates, and can also be used to prepare phosphine gas and the hexafluorophosphate anion, all previously available only downstream from white phosphorus.

Description: Cross-coupling chemistry is widely applied to carbon-carbon bond formation in the synthesis of medicines, agrochemicals, and other functional materials. Recently, single-electron–induced variants of this reaction class have proven particularly useful in the formation of C(sp 2 )–C(sp 3 ) linkages, although certain compound classes have remained a challenge. Here, we report the use of sulfones to activate the alkyl coupling partner in nickel-catalyzed radical cross-coupling with aryl zinc reagents. This method’s tolerance of fluoroalkyl substituents proved particularly advantageous for the streamlined preparation of pharmaceutically oriented fluorinated scaffolds that previously required multiple steps, toxic reagents, and nonmodular retrosynthetic blueprints. Five specific sulfone reagents facilitate the rapid assembly of a vast set of compounds, many of which contain challenging fluorination patterns.

Description: Plasmon-induced chemical reactions of molecules adsorbed on metal nanostructures are attracting increased attention for photocatalytic reactions. However, the mechanism remains controversial because of the difficulty of direct observation of the chemical reactions in the plasmonic field, which is strongly localized near the metal surface. We used a scanning tunneling microscope (STM) to achieve real-space and real-time observation of a plasmon-induced chemical reaction at the single-molecule level. A single dimethyl disulfide molecule on silver and copper surfaces was dissociated by the optically excited plasmon at the STM junction. The STM study combined with theoretical calculations shows that this plasmon-induced chemical reaction occurred by a direct intramolecular excitation mechanism.

Description: Identifying catalyst activation modes that exploit one-electron chemistry and overcome associated deactivation pathways will be transformative for developing first-row transition metal catalysts with performance equal or, ideally, superior to precious metals. Here we describe a zinc-activation method compatible with high-throughput reaction discovery that identified scores of cobalt-phosphine combinations for the asymmetric hydrogenation of functionalized alkenes. An optimized catalyst prepared from ( R , R )-Ph-BPE {Ph-BPE, 1,2-bis[(2 R ,5 R )-2,5-diphenylphospholano]ethane} and cobalt chloride [CoCl 2 ·6H 2 O] exhibited high activity and enantioselectivity in protic media and enabled the asymmetric synthesis of the epilepsy medication levetiracetam at 200-gram scale with 0.08 mole % catalyst loading. Stoichiometric studies established that the cobalt (II) catalyst precursor ( R , R )-Ph-BPECoCl 2 underwent ligand displacement by methanol, and zinc promoted facile one-electron reduction to cobalt (I), which more stably bound the phosphine.

Description: Transition metal–catalyzed arene functionalization has been widely used for molecular synthesis over the past century. In this arena, copper catalysis has long been considered a privileged platform due to the propensity of high-valent copper to undergo reductive elimination with a wide variety of coupling fragments. However, the sluggish nature of oxidative addition has limited copper’s capacity to broadly facilitate haloarene coupling protocols. Here, we demonstrate that this copper oxidative addition problem can be overcome with an aryl radical–capture mechanism, wherein the aryl radical is generated through a silyl radical halogen abstraction. This strategy was applied to a general trifluoromethylation of aryl bromides through dual copper-photoredox catalysis. Mechanistic studies support the formation of an open-shell aryl species.