Supramolecular self-organisation and conformational isomerism of a binuclear O,O′-dipropyl dithiophosphate gold(I) complex, [Au2{S2P(OC3H7)2}2]: Synthesis, 13C and 31P CP/MAS NMR spectroscopy, single-crystal X-ray diffraction study and thermal behaviour

Crystalline one-dimensional polymeric catena-poly[bis(mu(2)-O,O'-dipropyldithiophosphato-S,S')digold(I)] (Au-Au) (1) was prepared and studied using C-13 and P-31 CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. To elucidate the structural function of Dtph ligands in crystalline gold(I) O,O'-dipropyl dithiophosphate, the chemical shift anisotropy parameters (delta(aniso) and eta) were calculated from spinning sideband manifolds in P-31 MAS NMR spectra. A novel structure of the gold(I) compound comprises two isomeric, non-centrosymmetric binuclear molecules of [Au-2{S2P(OC3H7)(2)}(2)] (isomers 'A' and 'B'), whose four Dtph groups display structural inequivalence. In each isomeric binuclear molecule of 1, a pair of mu(2)-bridging dipropyl Dtph ligands almost symmetrically links two neighbouring gold atoms, forming an extensive eight-membered metallocycle [Au2S4P2] while the intramolecular aurophilic Au center dot center dot center dot Au bond additionally stabilises this central cyclic moiety. At the supramolecular level of complex 1, intermolecular aurophilic Au center dot center dot center dot Au bonds yield almost linear infinite polymeric chains (center dot center dot center dot'A'center dot center dot center dot'B'center dot center dot center dot'A'center dot center dot center dot center dot'B'center dot center dot center dot)(n). The thermal behaviour of this compound was studied by the simultaneous thermal analysis (STA) technique (a combination of TG and DSC) under an argon atmosphere. (C) 2015 Elsevier B.V. All rights reserved.