Simulation of mesogenic diruthenium tetracarboxylates: Development of a force field for coordination polymers of the MMX type

Abstract

A classical molecular mechanics force field, able to simulate coordination polymers (CP) based on ruthenium carboxylates (Ru2 (O2CReq )4 Lax) (eq = equatorial group containing aliphatic chains, Lax = axial ligand), has been developed. New parameters extracted from experimental data and quantum calculations on short aliphatic chains model systems were included in the generalized AMBER force field. The proposed parametrization was evaluated using model systems with known structure, containing either short or long aliphatic chains; experimental results were reproduced satisfactorily. This modified force field, although in a preliminary stage, could then be applied to long chain liquid crystalline compounds. The resulting atomistic simulations allowed assessing the relative influence of the factors determining the CP conformation, determinant for the physical properties of these materials.

Thermotropic mesomorphism of mixed-valent diruthenium aliphatic carboxylates with axial anion bearing two aliphatic chains

“…However, a renewed interest in both structural aspects (including supramolecular) [4][5][6][7][8][9][10][11] and physical properties [12][13][14][15][16] has emerged. As far as the molecular structuretype of mesophase relationship is concerned, the general trend is that nematic or smectic phases are usually found when Schiff bases, stilbazoles, or β-diketones are used as ligands (columnar mesophases have also been found when they carry several aliphatic chains), whereas metallophthalocyanines and bimetallic carboxylates usually have columnar mesophases.…”