Crystallography validates a model for the Supramolecular Architecture of Polymeric Metallomesogens

RICARDO F. BAGGIO; MARIA ANA CASTRO; FABIO D. CUKIERNIK

Osaka, Japón

Congreso; XXI Congress of the International Union of Crystallography; 2008

International Union of Crystallography

a - model b - structure The use of single-crystal crystallography as a direct tool for obtaining structural information at the molecular and supramolecular level, very useful in understanding physical properties of advanced materials, is precluded in liquid crystals (LC) due to their lack of long-range order. Their structural description often consist in models based on physico-chemical arguments, macro-structural information and local-probe evidences. Following this approach, we proposed1 a model for the remarkable LC columnar phases of diruthenium tri(alkoxy)benzoates ([Ru2(3,4,5‑(CnH2n+1O)3C6H2CO2)4Cl]x) in which the polymeric ...Ru2-Cl-Ru2-Cl-... strands exhibit “zig-zag” conformations with a Ru-Cl-Ru angle estimated as 112º (Figure 1a). We succeeded now to solve the structure of the n = 2 homologue. Its molecular structure corresponds to the typical lantern structure. Each chloride anion is coordinated to the axial positions of two different bimetallic units, giving rise to polymeric strands is in a zig-zag conformation (figure 2b); the experimental Ru‑Cl‑Ru = 118º and Ru-Ru-Cl = 170, 172° angles agree well with the predicted values.   1) M. Rusjan, B. Donnio, B. Heinrich, F. Cukiernik, D. Guillon, Langmuir 2002, 18, 10116.