X-ray investigations on the cyclopalladated mesogen bis-{5-(1-nonyl)-2{[4′1-nonyloxy)phenyl-2′-ato]}pyrimidine-N′,C²′]-μ-iodo}dipalladium(II)

Abstract

The cyclopalladated complex [Pd(L₃)(μ-I)]₂ ([Pd(L₃)(μ -I)]₂ = bis-{5-(1-nonyl)-2{[4′(1-nonyloxy)phenyl-2′-ato]}pyrimidine-N′,C²′]-μ-iodo}dipaladium (II); C→105·1°C (C₁)→128·1°C (S_A)→202·5°C (I)) has been investigated by X-ray diffraction and the electron density profile along the director, in the smectic phase, determined. [Pd(L₃(μ -I)]₂ is a mesogenic species with a lateral-lateral fused molecular shape whose main features are: (i) the solid C₁ phase when observed with a polarizing microscope gives a polygonal texture like a smectic A phase, and (ii) to describe properly the electron density profile along the director a model which takes into account a high electron density area (i.e. the four aromatic rings and the Pd₂I₂ fragment) extending perpendicular to the director is required.