Supramolecular associations in binary antimony(iii) dithiocarbamates: influence of ligand steric bulk, influence on coordination geometry, and competition with hydrogen-bonding

Abstract

New structural data for molecules of the general formula Sb(S₂CNR₂)₃, with both non-sterically and sterically demanding R groups, complement literature data and allow an assessment of factors dictating supramolecular association. With relatively small R substituents, dimer formation via Sb⋯S secondary interactions is observed. With bulky R groups, Sb⋯S interactions are not possible owing to steric hindrance and C–H⋯S hydrogen-bonding predominates instead, again leading to dimers. In cases where R carries hydrogen-bonding functionality, both Sb⋯S and O–H⋯O co-exist when R is small but Sb⋯S secondary bonding is switched off when R becomes larger. The conclusion of the study is that remote R substituents in molecules of this type are able to dictate modes of supramolecular association, i.e. Sb⋯S versus C–H⋯S, and that the resultant formation of loosely associated dimers facilitates efficient crystal packing.