ADVENTURES IN CRYSTAL ENGINEERING†
Edward R. T. Tiekink
Department of Chemistry, National University of Singapore, Singapore 117543
An overview of the structural systematics of four heavy-element systems is given, namely triorganotincarboxylates (R3Sn(O2CR’)), zinc and mercury xanthates (A(S2COR)2; A = Zn and Hg) and bismuth xanthates (Bi(S2COR)3). It will be demonstrated that there exists a fascinating range of structural diversity for these compounds, including differences in coordination number and molecular geometry. Difference in structure in two of the systems, i.e. R3Sn(O2CR’) and Zn(S2COR)2, are correlated with the nature of the tin- and ligand-bound R groups, respectively. This suggests a new design concept for crystal engineering, i.e. steric control over molecular aggregation. However, this concept is shown not to be universal by an analysis of the related Hg(S2COR)2 structures. The adoption of different motifs for Bi(S2COR)3 influences the nature of generated nanoparticles and thereby demonstrates the importance of structure of the precursor material. Finally, an example of the utility of non-traditional intermolecular ‘aurophilic’ (i.e. Au…Au) interactions upon polymer formation is demonstrated for a pair of phosphinegold(I) thiolate structures.