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111.
Dr. Manuel Hodecker Dr. Yury Kozhemyakin Svenja Weigold Dr. Frank Rominger Dr. Jan Freudenberg Prof. Dr. Andreas Dreuw Prof. Dr. Uwe H. F. Bunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(71):16990-16993
The synthesis of a doubly bridged 1,4-bis(phenylethynyl)benzene is reported. The target displays photophysical properties, distinctly different from that of its congeners, the singly bridged tolans. Quantum-chemical calculations suggest a lack of planarization of the bridged bis(phenylethynyl)benzene in the first excited state. 相似文献
112.
Koen Binnemans Dries Moors Tatjana N. Parac-Vogt Rik Van Deun Dirk Hinz-Hübner Gerd Meyer 《Liquid crystals》2013,40(9):1209-1216
Liquid crystalline complexes [Ln(LH)3Cl3] have been synthesized, where Ln is a trivalent lanthanide ion (Pr-Lu, except Pm) and where LH is the Schiff's base ligand N-octadecyl4-tetradecyloxysalicylaldimine. Although the ligand does not exhibit mesomorphism, the complexes do (SmA phase). The mesophase behaviour of these compounds has been investigated by polarizing optical microscopy, differential scanning calorimetry and high temperature X-ray diffraction. The lanthanide complexes have much higher melting and clearing points than comparable complexes with nitrate or dodecyl sulphate counterions. In addition, the transition temperatures are virtually independent of the type of lanthanide ion. This behaviour is opposite to that observed for similar complexes with nitrate counterions [Ln(LH)3(NO3)3]. The differences in temperature dependence can be related to structural differences. Whereas in the nitrate complexes the Schiff's base ligand binds in a zwitterionic form, two-dimensional 1H NMR correlation spectroscopy (COSY) of [Lu(LH)3Cl3] gives an indication that in the chloride complexes, besides coordination via the oxygen of molecules in the zwitterionic form, some of the Schiff's base ligands bind in a bidentate fashion (via the phenolic oxygen and the imine nitrogen). 相似文献