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Amela Arnold Tobias J. Sherbow Amanda M. Bohanon Richard I. Sayler R. David Britt Allison M. Smith James C. Fettinger Louise A. Berben 《Chemical science》2021,12(2):675
Ligand-based mixed valent (MV) complexes of Al(iii) incorporating electron donating (ED) and electron withdrawing (EW) substituents on bis(imino)pyridine ligands (I2P) have been prepared. The MV states containing EW groups are both assigned as Class II/III, and those with ED functional groups are Class III and Class II/III in the (I2P−)(I2P2−)Al and [(I2P2−)(I2P3−)Al]2− charge states, respectively. No abrupt changes in delocalization are observed with ED and EW groups and from this we infer that ligand and metal valence p-orbitals are well-matched in energy and the absence of LMCT and MLCT bands supports the delocalized electronic structures. The MV ligand charge states (I2P−)(I2P2−)Al and [(I2P2−)(I2P3−)Al]2− show intervalence charge transfer (IVCT) transitions in the regions 6850–7740 and 7410–9780 cm−1, respectively. Alkali metal cations in solution had no effect on the IVCT bands of [(I2P2−)(I2P3−)Al]2− complexes containing –PhNMe2 or –PhF5 substituents. Minor localization of charge in [(I2P2−)(I2P3−)Al]2− was observed when –PhOMe substituents are included.Organo-aluminum mixed-valent complexes combine properties of both organic and transition element mixed-valent compounds. This supports delocalized electronic structures that are structurally and electronically tunable. 相似文献
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de Swiet TM Yarger JL Wagberg T Hone J Gross BJ Tomaselli M Titman JJ Zettl A Mehring M 《Physical review letters》2000,84(4):717-720
We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 "equator," away from the interfullerene bonds. 相似文献
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It is natural to ask when a group has a planar Hasse lattice or more generally when its subgroup graph is planar. In this
paper, we completely answer this question for finite groups. We analyze abelian groups, p-groups, solvable groups, and nonsolvable groups in turn. We find seven infinite families (four depending on two parameters,
one on three, two on four), and three “sporadic” groups. In particular, we show that no nonabelian group whose order has three
distinct prime factors can be planar. 相似文献
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