Mechanochemical synthesis and thermal property investigation of metallomesogens and transition metal complexes

Abstract

Dialkyl 2,2′-bipyridyl-4,4′-dicarboxylate (L^βn, where βn refers to the number of carbons in β-substituted alkyl chain) complexes including PtL^β16Cl₂, CdL^β16Cl₂, [AgL^βnNO₃] and the dodecylsulfate salt [AgL^βn₂](DOS) were produced at reduced cost and in shorter times, compared to traditional solvent-based methods, by mechanochemical reaction in the absence of solvent. PtL^β16Cl₂ and the [AgL^βn₂](DOS) complexes are the first mesogenic transition metal complexes to be produced via ball milling. The effectiveness of a simple ligand modification, β- versus α-attachment of the alkyl functionalities to the ligand, is presented as a highly effective method for increasing the stable temperature range of a variety of metallomesogens and for producing sub-room-temperature liquid crystals.

Keywords:

• metallomesogen
• liquid crystal
• room-temperature liquid crystal
• ball mill
• mechanochemical
• mechanochemistry

Acknowledgements

Equipment was provided by the Jones/Ross Research Center at Murray State University (MSU). The authors are grateful for this contribution.