Linear Gold(Ⅰ) Coordination Polymers: A Polymer with a Unique Sine Wave Conformation

摘要

It is now well established that weak intra- and intermolecular bonding interactions between gold(Ⅰ) centers can give rise to unusual molecular conformations and crystal packing, but the discovery of new structural types has usually been serendipitous and the tailored engineering of supramolecular structures, which may have new and interesting properties as advanced materials, is still in its infancy. One example of controlled synthesis, is the selective formation of gold(Ⅰ) rings 1 from a precursor molecule 2 which is preorganized with syn-gold(Ⅰ) centers, due to intramolecular Au…Au bonding with the short-bite diphos-phine ligand Cy_2PCH_2PCy_2 (Cy = cyclohexyl), but formation of polymers 3 from a precursor molecule (4) with anti-gold(Ⅰ) centers, where intramolecular Au…Au bonding is impossible. It is then natural to ask the question: when will the crossover from ring to polymer occur in synthesis from precursors [(CH_2)_n(PPh_2AuX)_2], in which the shortest intramolecular Au…Au contact will naturally increase with the value of n? This paper reports results from this study, in which the largest gold(Ⅰ) ring yet known and a unique sine wave polymer have been prepared and structurally characterized.