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Prof. Dr. Heinz Langhals Dr. Bernd Böck M. Sc. Tanja Schmid Alexey Marchuk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13188-13194
Benzoperylene derivatives with two angularly attached dicarboxylic imide rings, which were prepared by the Diels–Alder‐Reaction, exhibit strong fluorescence and their free peri positions allow either control of the UV/Vis spectra through their substituents or form anchor positions for the attachment of functional units. The angular chromophore 3 may be used both for fluorescent labeling such as for primary amines or enzymes or as building blocks for more complex assemblies where they may act as energy donors for FRET or electron acceptors in PET such as for photovoltaic solar cells. 相似文献
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Abstract The changes in the characteristics of vibrational and optical properties of the conducting form of polypyrrole under pressure is studied. 相似文献
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The HfFe6Ge6-type compounds Gd0.8L0.2Mn6Sn6 and Tb0.8L0.2Mn6Sn6 (L = Sc, Y, Lu) have been studied by 119Sn Mössbauer spectroscopy. The values of the apparent quadrupolar splitting clearly evidence the easy plane magnetization of the gadolinium compounds and the easy axis one in the terbium compounds. The three tin sites behave differently with the nature and size of the substituting L element. For a given series, the hyperfine field of the Sn2d site is almost unchanged whatever the size of the L element. The hyperfine field of the Sn2e site strongly varies with the L size in relation with atomic displacements. The hyperfine field of the Sn2c site exhibits a more complicated behavior. The field difference in the easy plane and easy axis compounds confirms the angle-dependent anisotropic contribution of the Mn moment to the hyperfine field. The analysis of the results also suggests the play of angle-dependent contributions arising from the rare earth moment. 相似文献
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Dipl.‐Chem. Alexander Zhdanko Dr. Markus Ströbele Prof. Dr. Martin E. Maier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(46):14732-14744
Coordination chemistry of gold catalysts bearing eight different ligands [L=PPh3, JohnPhos (L2), Xphos (L3), DTBP, IMes, IPr, dppf, S‐tolBINAP (L8)] has been studied by NMR spectroscopy in solution at room temperature. Cationic or neutral mononuclear complexes LAuX (L=L2, L3, IMes, IPr; X=charged or neutral ligand) underwent simple ligand exchange without giving any higher coordinate complexes. For L2AuX the following ligand strength series was determined: MeOH?hex‐3‐yne <MeCN≈OTf??Me2S<2,6‐lutidine<4‐picoline<CF3CO2?≈DMAP<TMTU<PPh3<OH?≈Cl?. Some heteroligand complexes DTBPAuX exist in solution in equilibrium with the corresponding symmetrical species. Binuclear complexes dppf(AuOTf)2 and S‐tolBINAP(AuOTf)2 showed different behavior in exchange reactions with ligands depending on the ligand strength. Thus, PPh3 causes abstraction of one gold atom to give mononuclear complexes LLAuPPh3+ and (Ph3P)nAu+, but other N and S ligands give ordinary dicationic species LL(AuNu)22+. In reactions with different bases, LAu+ provided new oxonium ions whose chemistry was also studied: (DTBPAu)3O+, (L2Au)2OH+, (L2Au)3O+, (L3Au)2OH+, and (IMesAu)2OH+. Ultimately, formation of gold hydroxide LAuOH (L=L2, L3, IMes) was studied. Ligand‐ or base‐assisted interconversions between (L2Au)2OH+, (L2Au)3O+, and L2AuOH are described. Reactions of dppf(AuOTf)2 and S‐tolBINAP(AuOTf)2 with bases provided more interesting oxonium ions, whose molecular composition was found to be [dppf(Au)2]3O22+, L8(Au)2OH+, and [L8(Au)2]3O22+, but their exact structure was not established. Several reactions between different oxonium species were conducted to observe mixed heteroligand oxonium species. Reaction of L2AuNCMe+ with S2? was studied; several new complexes with sulfide are described. For many reversible reactions the corresponding equilibrium constants were determined. 相似文献