Syntheses, structures, and mesomorphic properties of two series of oxovanadium(IV) salen and salpn complexes with 4-substituted long alkoxy chains

摘要

Two series of oxovanadium(IV) salen and salpn complexes containing 4-substituted alkoxy chains of aromatic rings, [VO((4-CnH2n+1O)(2)salen)] (n = 3 (1), 4 (2), 6 (3), 8 (4), 10 (5), 12 (6), 14 (7), 16 (8), 18 (9), and 20 (10) and salen = N,N'-ethylenebis(salicylideneiminato)), and [VO((4-CnH2n+1O)(2)salpn)] (n = 8 (11), 10 (12), 12 (13), 14 (14), 16 (15), and 18 (16) and salpn = N,N'-propylenebis(salicylideneiminato)), have been prepared and their mesomorphic properties have been investigated. The crystal structures of 1-9 except for 7 by an X-ray crystallographic analysis have been revealed. Complexes 4-9 in the solid state have been confirmed as novel bilayer crystal structures composed of only the VO(IV) complex without linear chains via the V=O units. The VO(IV) complexes with longer alkoxy chains of 8-10 transferred from the bilayer crystal to the bilayer metallomesogens (liquid crystals). Based on the X-ray analyses and the precise extinction rules for 8-10 with the bilayer metallomesogens, complexes 8-10 were identified as the liquid crystalline (M(Pa2(1))) phase derived from 80 layer groups, On the other hand, the 4-alkoxysalpn complexes of 14-16 showed the unusual rectangular columnar mesophase (Col(Gamma)) with the linear chain via the V=O units supported by the existence of the V=O stretching band characteristic of weak linear chain formation via the V=O units in the liquid crystal. (c) 2006 Elsevier B.V. All rights reserved.