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Discotic Metallomesogens: Effects of Sidechains Density in Transition Metal Bis(β‐Diketonate) Complexes
Author(s) -
Fan PeiChen,
Lai Chung K.
Publication year - 1996
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199600049
Subject(s) - mesophase , chemistry , discotic liquid crystal , side chain , mesogen , crystallography , alkoxy group , copper , liquid crystal , columnar phase , steric effects , metal , stereochemistry , alkyl , molecule , organic chemistry , phase (matter) , polymer , liquid crystalline , condensed matter physics , physics
The preparation and mesogenic properties of a series of discotic β‐diketonate metal complexes are reported. The results show that the density of side chains, positions of side chains, and the geometries of the metal centers play important roles in determining the mesomorphic behaviors and thermodynamic stability of these complexes. In the series of copper complexes 3, all these disc‐like molecules with eight alkoxy side chains exhibit columnar hexagonal disordered (D hd ) mesophases. In the series of copper complexes 2 with six side chains, only compounds substituted with longer alkoxy chains (n = C 14 or C 16 ) exhibit discotic columnar mesophase. However, in the series of complexes 1, only crystal‐to‐isotropic transitions were observed. The results showed that induction of liquid crystallinity not only depends on the numbers of side chains (i.e. side chain density), but also on the degree of distribution over the central core. Palladium complexes analogs exhibit similar discotic mesophases, and due to their greater core‐core organization, they also have higher clearing points and wider temperature range of mesophases than copper complexes.