ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Fluorescence-dip infrared spectroscopy of tropolone and tropolone-OD (1996)

Frost, Rex K. ; Hagemeister, Fredrick C. ; Arrington, Caleb A. ; [et al.]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 105 (1996), S. 2595-2604

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: Fluorescence-dip infrared spectroscopy (FDIRS) is employed to record the infrared spectra of the isolated, jet-cooled tropolone molecule (TrOH) and its singly deuterated isotopomer TrOD in the O–H and C–H stretch regions. The ability of the method to monitor a single ground-state level enables the acquisition of spectra out of the lower and upper levels of the zero-point tunneling doublet free from interference from one another. The high power of the optical parametric oscillator used for infrared generation produces FDIR spectra with good signal-to-noise despite the weak intensity of the C–H and O–H stretch transitions in tropolone. The expectation that both spectra will exhibit two OH stretch transitions separated by the OH(v=1) tunneling splitting is only partially verified in the present study. The spectra of TrOH are compared with those from deuterated tropolone (TrOD) to assign transitions due to C–H and O–H, which are in close proximity in TrOH. The appearance of the spectra out of lower (a1 symmetry) and upper (b2 symmetry) tunneling levels are surprisingly similar. Two sharp transitions at 3134.9 cm−1 (out of the a1 tunneling level) and 3133.9 cm−1 (out of the b2 tunneling level) are separated by the ground-state tunneling splitting (0.99 cm−1), and thereby terminate in the same upper state tunneling level. Their similar intensities relative to the C–H stretch transitions indicate that the y- and z-polarized transitions are of comparable intensity, as predicted by ab initio calculations. The corresponding transitions to the other member of the upper state tunneling doublet are not clearly assigned by the present study, but the broad absorptions centered about 12 cm−1 below the assigned transitions are suggested as the most likely possibility for the missing transitions. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.472119

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Fluorescence-dip infrared spectroscopy of the tropolone-H2O complex (1996)

Frost, Rex K. ; Hagemeister, Fredrick C. ; Arrington, Caleb A. ; [et al.]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 105 (1996), S. 2605-2617

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: Fluorescence dip infrared spectroscopy (FDIRS) is used to probe the effect of a solvent water molecule on intramolecular H-atom tunneling in tropolone. As with the bare molecule discussed in paper I, the FDIR spectrum of the tropolone-H2O complex is recorded in the O–H and C–H stretch regions. Three OH stretch fundamentals are observed in the spectrum, and can be assigned nominally to a free OH stretch of the water molecule (3724 cm−1), a hydrogen bonded OH stretch of water (3506 cm−1), and the OH stretch of tropolone (∼3150 cm−1). The breadth and complexity of the bands is highly mode specific. The free OH stretch transition is sharp (1.8 cm−1 FWHM) and has weak combination bands built on it at +73 and +1600 cm−1. The former is assigned to a combination band with the in-plane bending mode of the tropolone-H2O hydrogen bond, while the latter is the free OH/intramolecular water bend combination band. The water hydrogen-bonded OH fundamental is also a sharp transition which, after correction for the decreased infrared power at its frequency, is clearly the strongest transition in the spectrum. It is flanked by three close-lying satellite bands 13, 23, and 34 cm−1 above it, and also supports a weak combination band at +69 cm−1 due to the in-plane intermolecular bending mode. The tropolone OH absorption is in the same frequency region as in the bare molecule, but broadened to over 100 cm−1 in TrOH–H2O. Distinct substructure in the band is present, with spacings reminiscent of those in the water H-bonded OH stretch region. Ab initio calculations on tropolone-H2O are carried out at both the MP2 and Becke3LYP levels of theory. Two isomers with similar binding energies and vibrational frequencies are identified. In one isomer (isomer I), the water molecule serves as a hydrogen-bonded bridge between the tropolone OH and keto groups. In the other (isomer II), the water molecule is exterior to the tropolone and hydrogen bonded to the keto oxygen. The experimental evidence does not conclusively distinguish between these two possibilities, though the exterior structure seems somewhat more in keeping with the data as a whole. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.472125

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

The hydrogen-bonding topologies of indole–(water)n clusters from resonant ion-dip infrared spectroscopy (1998)

Carney, Joel R. ; Hagemeister, Fredrick C. ; Zwier, Timothy S.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 108 (1998), S. 3379-3382

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: A combination of resonant two-photon ionization, infrared-ultraviolet hole burning, and resonant ion-dip infrared spectroscopies are used to assign and selectively probe the hydrogen bonding topologies of indole–(water)n clusters with n=1,2. The indole–(water)1 complex is confirmed to possess the N−H(centered ellipsis)OH2 structure surmised from previous studies. However, the bands in the ultraviolet previously assigned to a π H-bound indole–water complex are shown to be due instead to the indole–(water)2 cluster in which the water dimer forms a H-bonded bridge between the N–H and aromatic π clouds of indole. The implications of this reassignment for our understanding of the influence of H-bonding solvents on indole's fluorescence properties are discussed. © 1998 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.475356

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Resonant ion-dip infrared spectroscopy of the S4 and D2d water octamers in benzene-(water)8 and benzene2-(water)8 (1998)

Gruenloh, Christopher J. ; Carney, Joel R. ; Hagemeister, Fredrick C. ; [et al.]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 109 (1998), S. 6601-6614

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: The techniques of resonant two-photon ionization (R2PI), UV–UV (ultraviolet) hole-burning, and resonant ion-dip infrared (RIDIR) spectroscopies have been employed along with density functional theory (DFT) calculations to assign and characterize the hydrogen-bonding topologies of two isomers each of the benzene-(water)8 and (benzene)2(water)8 gas-phase clusters. The BW8 isomers (B=benzene, W=water) have R2PI spectra which are nearly identical to one another, but shifted by about 5 cm−1 from one another. This difference is sufficient to enable interference-free RIDIR spectra to be recorded. As with smaller BWn clusters, the BW8 clusters fragment following photoionization by loss of either one or two water molecules. The OH stretch IR spectra of the two BW8 isomers bear a close resemblance to one another, but differ most noticeably in the double-donor OH stretch transitions near 3550 cm−1. Comparison to DFT calculated minimum energy structures, vibrational frequencies, and infrared intensities leads to an assignment of the H-bonding topology of the BW8 isomers as nominally cubic water octamers of S4 and D2d symmetry surface attached to benzene through a π H-bond. A series of arguments based on the R2PI and hole-burning spectra leads to an assignment of additional features in the R2PI spectra to two isomers of B2W8. The OH stretch RIDIR spectra of these isomers show them to be the corresponding S4 and D2d analogs of B2W8 in which the benzene molecules each form a π H-bond with a different dangling OH group on the W8 sub-cluster. © 1998 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.477346

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Resonant ion-dip infrared spectroscopy of benzene–(water)9: Expanding the cube (2000)

Gruenloh, Christopher J. ; Carney, Joel R. ; Hagemeister, Fredrick C. ; [et al.]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 113 (2000), S. 2290-2303

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: The techniques of resonant two-photon ionization (R2PI), UV-UV hole-burning, and resonant ion-dip infrared (RIDIR) spectroscopy have been employed along with density functional theory (DFT) calculations to characterize the hydrogen-bonding topologies of three isomers of benzene–(water)9. Isomers I and II, with R2PI transitions shifted, respectively, by +77 and +63 cm−1 from the benzene monomer, have similar intensities in the R2PI spectrum. The signal from the third isomer (isomer III, shifted +60 cm−1) is present at about one-fourth the intensity of the other two. The experimental RIDIR spectrum of isomer I bears a strong resemblance to the spectrum of the benzene–(water)8 D2d-symmetry cubic structure identified in earlier work, but possessing an extra single-donor transition associated with the ninth water molecule. Using the S4 and D2d symmetry forms of the water octamer as base structures to which the ninth water molecule can be added, a total of nine "expanded-cube" structures are identified for W9 arising from two distinct insertion points in the W8(D2d) cube (D1,D2) and three such points in the W8(S4) cube (S1-S3). DFT calculations predict these to be spread over an energy range of less than 1 kcal/mol. Given that each of the nine "expanded-cube" (water)9 structures contains five symmetry-inequivalent free OH groups, a total of 45 "expanded-cube" benzene–(water)9 conformational isomers are predicted. Structural and vibrational frequency calculations have been performed on seven of these to determine how the (water)9 structural type and the attachment point of benzene to the structure affect the total energy and vibrational frequencies of the cluster. Based on a comparison of the experimental RIDIR spectrum with the calculated vibrational frequencies and infrared intensities, isomer I is attributed to the BW9(D1) structure in which benzene attaches to W9(D1) at the free OH of the water molecule which donates a H-bond to the ninth water. This structure has a calculated binding energy that is about 0.13 kcal/mol greater in magnitude than any other benzene–(water)9 isomer studied. The experimental spectra of isomers II and III are of insufficient quality to assign them to specific BW9 structures with confidence. However, isomer II is most consistent with an S4-derived expanded cube structure (either S1 or S2), while isomer III shows characteristics consistent with a second D1-derived BW9 structure in which benzene is attached at a position on the expanded cube remote from the ninth water. © 2000 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.482044

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Resonant ion-dip infrared spectroscopy of benzene–(methanol)m clusters with m=1–6 (1997)

Pribble, R. Nathaniel ; Hagemeister, Fredrick C. ; Zwier, Timothy S.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 106 (1997), S. 2145-2157

add to mindlist on the mindlist

Details

ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: Resonant ion-dip infrared spectroscopy has been employed to record cluster-size-specific spectra of C6H6–(CH3OH)m with m=1–6 in the OH stretch fundamental region. The comparison of the spectra with the results of ab initio calculations on the pure methanol clusters enables the assignment of the hydrogen-bonding architecture in the clusters. In all cases, the methanol molecules aggregate together in a single subcluster. With m=1, a single infrared transition is observed, redshifted from that of a free methanol momomer by 42 cm−1 due to π hydrogen bonding between benzene and methanol. The m=2 spectrum features two strong transitions at 3506 and 3605 cm−1. The lower frequency peak is redshifted from the free monomer value by 175 cm−1 and is assigned to the proton donor in the methanol dimer subcluster. The proton acceptor, which would be a free OH stretch in the absence of benzene, is redshifted by 76 cm−1 due to a strengthened π hydrogen bond. In benzene–(CH3OH)3, three sharp OH stretch transitions are observed at 3389, 3435, and 3589 cm−1. The comparison of these absorptions with ab initio calculations and with experiments on the pure methanol trimer leads to a structure for benzene–(CH3OH)3 which incorporates a π hydrogen-bonded methanol trimer chain, confirming the earlier assignment based on its ultraviolet spectrum. The 3589 cm−1 transition, due to the π hydrogen bond of the terminal methanol, is redshifted from the free monomer by 93 cm−1, a value approaching that of the donor methanol in methanol dimer (−107 cm−1). The lower frequency transitions in the m=3 spectrum arise from the donor–acceptor and donor OH stretches in the methanol trimer chain. The spectral characteristics change when m=4. The OH stretch transitions are all located in a region around 3320 cm−1 and are significantly broadened compared to the smaller clusters. By comparison with ab initio calculations, the methanol tetramer structure in benzene–(CH3OH)4 is deduced to be a cyclic methanol tetramer. The spectra for m=5 and 6 are slightly redshifted but similar to m=4 and point toward cyclic structures as well. © 1997 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.473784

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Chemotherapy induces transient sex chromosomal and autosomal aneuploidy in human sperm (1997)

Robbins, Wendie A. ; Meistrich, Marvin L. ; Moore, Dan ; [et al.]

[s.l.] : Nature Publishing Group

Nature genetics 16 (1997), S. 74-78

add to mindlist on the mindlist

Details

ISSN: 1546-1718

Source: Nature Archives 1869 - 2009

Topics: Biology , Medicine

Notes: [Auszug] Aneuploidy, a major category of chromosomal defects in humans, is responsible for large portions of pregnancy loss and chromosomal abnormality syndromes detected at birth (4/1,000 live births are aneuploid). The paternal contribution to aneuploidy is substantial, especially for the sex ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/ng0597-74

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

8

Electronic Resource

Phase II Study of Paclitaxel in Combination with Mitoxantrone and Ifosfamide/Mesna for Patients with Relapsed or Refractory Non-Hodgkin's Lymphoma after Failure to Cytarabine/Cisplatin Combination (1999)

Romaguera, Jorge E. ; Rodriguez, M. Alma ; Hagemeister, Fredrick B. ; [et al.]

Springer

Investigational new drugs 17 (1999), S. 187-192

add to mindlist on the mindlist

Details

ISSN: 1573-0646

Keywords: relapsed NHL ; paclitaxel ; MINT chemotherapy

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Medicine

Notes: Abstract Purpose: Evaluate response, duration of response, and toxicity of paclitaxel in combination with other drugs known to be effective in non-Hodgkin's lymphoma (NHL). Methods: Thirty-eight patients with relapsed/refractory NHL who had been exposed to doxorubicin as well as the cytarabine-cisplatin combinations received Mesna 1.33 gm/M2/D daily days 1, 2, 3 IV over 1 hour; ifosfamide 1.33 gm/M2/D daily days 1, 2, 3 IV over 1 hour (same bag); Novantrone 8 mg/M2/D IV day 1; and Taxol 27.5 mg/M2/D daily days 1, 2, 3, 4 by continuous 24-hour intravenous infusion. Premedication for Taxol included dexamethasone, diphenhydramine, and cimetidine on day 1. Results: Of 35 evaluable patients, 9 (26%) achieved a complete response and 7 (20%) a partial response for a total response rate of 46%. The median failure-free and overall survival times were 2 and 10 months, respectively. Major toxicity was hematologic with a median absolute neutrophil nadir of 196/mm3. Only 10% of the cycles were associated with a grade 3−4 infection. Conclusion: MINT is an active and safe regimen for relapsed/refractory NHL that have failed both an Adriamycin-containing regimen and a cytarabine/cisplatin-containing regimen.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1006383503022

Permalink