Crystal Engineering of Gold(I) Thiolate Based Compounds via Cooperative Aurophilic and Hydrogen-Bonding Interactions

Abstract

Treatment of sodium 2-amino-5-mercapto-1,3,4-thiadiazolate (NaSSNH2) with monophosphines (triphenylphosphine and trimethylphosphine) and diphosphines [bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), and trans-1,2-bis(diphenylphosphino)ethene (dppee)] affords a series of gold(I) thiolates with the respective stabilizing phosphine ligands [Au(PR3)(SSNH2)] (R = Ph 1 and Me 2) and [PP(Au(SSNH2))2] (PP = dppm 3, dppe 4 and dppee 5). The crystal structures of the complexes have been determined by single-crystal X-ray diffraction studies, confirming hydrogen-bonded frameworks in the crystal lattices based on the functions of the SSNH2 ligands. The triphenylphosphine complex 1 (with crystal diethyl ether, 1·0.5Et2O) forms a dimer solely via bifurcated hydrogen bonds. In the presence of crystal methanol (1·MeOH) it gives rise to a one-dimensional ladder structure via intermolecular hydrogen-bonding interactions with molecules of crystal methanol as bridges. With a reduced steric effect of the auxiliary ligand, the trimethylphosphine analogue 2 forms a novel two-dimensional sheet structure via cooperative intermolecular aurophilic [Au(I)···Au(I) 3.0581(6) Å] and hydrogen-bonding interactions. The bis(diphenylphosphino)methane complex 3·2DMF features dinuclear units associated into a meandering chain structure via intramolecular aurophilic and intermolecular hydrogen bonding interactions. Further aggregation is terminated by hydrogen-bonding to crystal solvent molecules. 4·0.5MeOH forms a complicated network via cooperative intermolecular aurophilic [Au(I)···Au(I) 3.0675(7) Å] and hydrogen-bonding interactions. With DMF as a chain-terminating solvent molecule, the trans-1,2-bis(diphenylphosphino)ethylene complex 5·4DMF can only form isolated dinuclear units hydrogen bonded to these solvent molecules. Complexes 2 and 4 are rare examples of two-dimensional frameworks built on cooperative intermolecular aurophilic and hydrogen-bonding interactions in the solid state.