Pyrazole-based allylpalladium complexes: Supramolecular architecture and liquid crystal behaviour
摘要:
The co-ordination of non-mesomorphic 3-substituted pyrazoles Hpz(R) to the [Pd(eta(C3H5)-C-3)](+) fragment gives rise to four-coordinated complexes [Pd(eta(3)-C3H5)(Hpz(R))(2)](+) (R = C6H4OCnH2n+1; n = 12 (I-12), 14 (I-14), 16 (I-16), 18 (I-18)), which were isolated with BF4- as counteranion. The new complexes are proved to have liquid crystal properties exhibiting monotropic or enantiotropic smectic A (SmA) mesophases at low temperatures which range between ca. 40 and 80 degrees C. The crystal structure of I-12 presents a 2D network highly interdigitated, which could be related with the layered structure proposed in the liquid crystalline phase through the X-ray diffraction at variable temperature. (C) 2006 Elsevier B.V. All rights reserved.
Pyrazole-based allylpalladium complexes: Supramolecular architecture and liquid crystal behaviour
摘要:
The co-ordination of non-mesomorphic 3-substituted pyrazoles Hpz(R) to the [Pd(eta(C3H5)-C-3)](+) fragment gives rise to four-coordinated complexes [Pd(eta(3)-C3H5)(Hpz(R))(2)](+) (R = C6H4OCnH2n+1; n = 12 (I-12), 14 (I-14), 16 (I-16), 18 (I-18)), which were isolated with BF4- as counteranion. The new complexes are proved to have liquid crystal properties exhibiting monotropic or enantiotropic smectic A (SmA) mesophases at low temperatures which range between ca. 40 and 80 degrees C. The crystal structure of I-12 presents a 2D network highly interdigitated, which could be related with the layered structure proposed in the liquid crystalline phase through the X-ray diffraction at variable temperature. (C) 2006 Elsevier B.V. All rights reserved.