The ESR study of chemical interactions in triple solid silver–carbon tetrachloride–mesogenic cyanobiphenyl co-condensate system

Abstract

The possibilities of new metal–mesogenic complexes formation and their solid phase chemical reactions have been demonstrated using low temperature co-condensation technique and ESR-spectroscopy for solid triple system, containing silver, mesogenic ligand 4-pentyl-4-cyanobiphenyl (5CB) and alternative electron-acceptor ligand or the third reactive component carbon tetrachloride (CCl₄). It was shown by ESR-spectroscopy that the existence of four paramagnetic products are stabilized in the system at low temperatures: silver atom π-complex with two cyanobiphenyl molecules, silver atom σ-complex with cyanobiphenyl molecule stabilized by CCl₄ co-ligand, complex of AgCl molecule with trichloromethyl radical – AgCl·CCl₃ and silver nanoclusters – Ag_x, formed by silver atoms aggregation in mesogenic matrix. The relative thermal stability of these silver species and mechanism of their thermal behavior are discussed.

Introduction

Nowadays, the possibilities of the use of supramolecular organised systems for production of highly ordered nanostructures are an attractive route for the investigators in the field of nanochemistry and nanotechnology [1], [2], [3], [4], [5]. The mesogenic matrices which possess the diversely molecular organised phases in the solid and liquid crystalline states are of great interest for synthesis of anisotropic metal nanoparticles and their highly ordered assemblies [6], [7]. In the present work, the specific features of mesogenic ordering effect on the processes of metal atoms aggregation and on the chemical interactions of metal species of different size were studied on the example of silver atoms and nanocluster's interaction with carbon tetrachloride (CCl₄) in low temperature mesogenic matrix of 4-pentyl-4-cyanobiphenyl (5CB).