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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 96 (1993), S. 32-39 
    ISSN: 1432-1939
    Keywords: Formicidae ; Leptothorax ; Queen polymorphism ; Wing reduction ; Colony founding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In two nearctic ants, Leptothorax canadensis and Leptothorax sp. A, young queens may either found their own nest solitarily after mating or seek adoption into an established colony. Whether a queen disperses or not is associated with genetically determined queen morphology in Leptothorax sp. A. Whereas a majority of winged queens attempt solitary colony founding after mating, most wingless, intermorphic queens return to their maternal nests and new colonies are founded by budding after hibernation. The latter strategy appears to be correlated with patchy, isolated habitats, whereas in extended boreal forests dispersal on the wing is probably more common. Alternative dispersal strategies strongly affect the average number of queens per colony and seasonal fluctuations of colony structure.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Behavioral ecology and sociobiology 45 (1999), S. 151-159 
    ISSN: 1432-0762
    Keywords: Key words Reproductive competition ; Ants ; Aggression ; Dominance rank ; Fertility recognition ; Leptothorax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most species of advanced eusocial insects, the partitioning of reproduction between nestmates is thought to be regulated by means of primer pheromones or other chemical cues, which presumably influence the behavior of co-queens and workers such that they maximize their own inclusive fitness. Here we show that in multi-queen colonies of the Nearctic ant, Leptothorax sp. A, physical dominance in concert with chemical cues, which signal the ovarian development of a queen, are used to control reproduction of competing queens and to influence worker behavior. The analysis of ranks obtained during two fighting periods in the annual colony cycle revealed a strong link between individual aggressiveness of a queen and her fertility. During the adoption of newly mated queens in autumn, the resident, egg-laying α-queen was more likely to start aggression first and keep her high rank position compared to the fighting period after hibernation. We suggest that this is proximately caused by the α-queen having much stronger developed ovaries in autumn than the young queens, whereas after hibernation, the ovaries of all queens are similarly inactive. Interactions during the first weeks after the end of hibernation and intrinsic, individual differences in aggressiveness appear to be crucial for the dominance rank achieved later. Queens which were allowed to become fertile when their nestmate queens still were kept under prolonged hibernation, were immediately socially dominant over the latter when all queens were reunited, though no aggression occurred. In another experiment, queen antagonism was prevented by spatial separation in different parts of the same nest and all queens began to lay eggs. Workers stayed preferentially with queens with high actual fecundity rather than with those which had had high social status before separation. This and further evidence suggest that ovarian status is communicated, most likely by a chemical cue perceived by co-queens and workers, affects the direction of their aggressive behavior, and allows them to discriminate among queens.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1572-1577 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of 2,2′-Bisoxazolyls and 2,2′ -Bisthiazolyls, of Arylene-bis-2-oxazolyl and Arylenebis-2-thiazolyl DerivativesThe reaction of desylamine hydrochloride with carboxylic acid chlorides and dicarboxylic acid chlorides yields ms- (acylamino) desoxybezoins (2a, b) and amides of N, N′ -bis-desyldicarboxylic acids (2c,-f), respectively. These compounds are converted by condensation with phosphorus pentachloride to derivatives of oxazole (3) and by condensation with phosphorus pentasulfide to derivatives of thaizole(4).
    Notes: Durch Umsetzung von Desylaminhydrochlorid mit Carbonsäurechloriden bzw. mit Dicarbonsäuredichloriden gelangt man zu ms-Acyalmino -desoxybenzoinen (2a, b) bzw. zu N. N′-Bis-desyl- dicarbonsäurediamiden (2c-f). Diese lassen sich mit Phosphorpentachlorid zu Oxazolderivaten 3, mit Phosphorpentasulfid zu Thiazolderivaten 4 kondensieren.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2987-2989 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2415-2417 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ESR and cyclic voltammetry investigations show that isomerization of the radical cation of cis-1,1′-azonorbornane (cis-1) to the trans-radical ion proceeds too fast in solution for direct investigation of the cis-radical ion even at -78°. The facile isomerization of the radical cation is in agreement with PM3 calculations proposing an activation barrier of only 17 kJ/mol. As a consequence, quantitative cis → trans isomerization of 1,1′-azonorbornane can effectively be accomplished by addition of catalytic amounts of one-electron oxidants. This is the first evidence for a radical-cation-catalyzed cis → trans isomerization of azo compounds.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 75 (1992), S. 2307-2316 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Seven redox stages, the dication 12+, the radical cation \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{+}\kern-4pt {.}\kern-2pt }}$\end{document}, the neutral 1, the radical anion \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}, the dianion 12-, the radical trianion \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {3{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}\end{document}, and the tetraanion 14-, are indicated by cyclic voltammetry for the bisphane 1, in which the benzene decks of two lateral paracyclophane moieties are orthogonal to the plane of anthracene framework. In \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{+}\kern-4pt {.}\kern-2pt }}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}, the unpaired electron is accommodated into the central anthracene subsystem, and the same statement holds for the two positive or negative charges in 12+ and 12-. Formation of \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {3{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}\end{document} and 1- occurs through admission of additional electrons one-by-one into the two paracyclophane moieties flanking the doubly charged anthracene subsystem in 12-. The above-postulated, successive release or uptake of electrons by the individual parts of the bisphane is in perfect accord with the hyperfine data determined by ESR and ENDOR spectroscopy for \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{+}\kern-4pt {.}\kern-2pt }}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$1^{\scriptstyle {3{\relbar}\kern-4pt {.}\kern-2pt }}$\end{document}\end{document}, as well as for radical ions of suitable reference compounds.
    Additional Material: 6 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 243-250 
    ISSN: 0009-2940
    Keywords: Cyanide complexes, organometallic, polynuclear / Redox chemistry / Ruthenium clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Redox Chemistry, Dinuclear Complexes, and Ru3,-Cluster Derivatives of the “Ligand” [Cp(CO)2Mn - CN]-By means of the compounds Na[Cp(CO)2MnCN] (1a, b) the abilities of the cyanide ion to link different organometallic units and to stabilize unusual electron counts in organometallic complexes were tested. The dinuclear complexes [Cp(CO)2Mn-CN-M]- [form M = MnCp(CO)2 and W(CO)5 as PPN salts 2a, 3a] as well as Cp(CO)2Mn-Cn-M [for M = MoCp(CO)3 and NiCpPPh3, 4a, 5a] were obtained in a pure state. From the reactions with Ru3(CO)12 the cluster derivatives HRu3(CO)10[μ-NC-Mn(CO)2Cp] (6a, b) and Ru3(CO)10[μ-NC-Mn(CO)2Cp]2 (7b) were characterized. One-electron transfers were investigated for the starting complex and for the two anionic dinuclear complexes 2a, 3a. Crystal structures were determined of the dinuclear Mn-CN-Mn compex 2a and of the two cluster derivatives 2b, 7b.
    Additional Material: 5 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2403-2408 
    ISSN: 0009-2940
    Keywords: Ferrocene ; Crown ethers ; Cryptands ; Redox switching ; Protonation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 1,1′-ferrocenylene-bis(methylenepyridinium) tosylate chloride (1) with aza-x-crown-y (x/y = 12/4; 15/5; 18/6) gives the three novel ferrocene biscrown ethers 1,1′-ferrocenylene-bis(methylene-aza-x-crown-y) (x/y = 12/4, 2; 15/5, 3; 18/6, 4). The reaction of 1 with diaza-18-crown-6 represents a new and simple route to the known ferrocene cryptands 1,1′-zacyclooctadecane)] (5) and 1,1″:1′,1″-bisferrocenylene-bis-[bis-7,16-methylene(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane)] (6). The solid-state structure of 5 is described. The ferrocene bridge compresses the diaza crown ether leading to an internitrogen distance of 458 pm. The stoichiometry of Na+ and K+ complexes with 2 and 3 in CD3CN determined in NMR titration experiments suggests the formation of Na+ and K+ crown ether sandwich complexes in solution. Cyclic voltammograms of 2 and 5 in the presence of varying amounts of H+ and Na+ have been recorded. The redox potential of ferrocene is shifted by +180 mV in the case of 5 · Na+ and up to +600 mV in the case of 5 · H+H+ relative to 5, but only by + 70 mV with 2 · Na+ and 2. The protonation of 5 give rises to several isomers (exo and endo protonation) which differ significantly in their redox potential. The extremely large positive shift of the oxidation potential of the diprotonated ferrocene cryptand corresponds to an increase in the acidity of 5 · H+H+ upon oxidation by more than ten orders of magnitude and makes this system a candidate for the directed membrane transport of protons.
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 101 (1968), S. 3504-3516 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Derivaten des ms-[N-Acyl-anilino]-desoxybenzoins 3 entstehen durch Einwirkung von Phosphorpentachlorid substituierte ms-[N-(α-Chlor-aryliden)-anilinio]-desoxybenzoin-chloride 4. Bei der Umsetzung mit überschüssigem Ammoniak gehen diese in 1.2.4.5-tetraaryl-substituierte Imidazole 5 über. Setzt man 4 mit primären Aminen um, so bilden sich Derivate der N-Desyl-amidinium-chloride 6, die bei Einwirkung von Thionylchlorid Wasser abspalten und unter Ringschluß in 1.2.3.4.5-pentaaryl-substituierte Imidazolium-Salze 7 übergehen. Eine größere Zahl neuer Imidazolderivate war auf dem beschriebenen Weg in guten Ausbeuten zugänglich.
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