Gallium and indium compounds of sulphur donor ligands: Pyridine-2-thiolates and diphenylthiophosphinates

Abstract

The reaction of GaR 3 ( R = t Bu, Me ) with 1, 2, or 3 molar equivalents of 2-mercaptopyridine (HSpy) yielded Ga(R) 2(Spy) [ R = t Bu ( 1), Me( 2) ], Ga(R)(Spy) 2 [ R = t Bu ( 3), Me ( 4) ], and Ga(Spy) 3, ( 5), respectively. Reaction of GaCl 3 and HSpy in the presence of NEt 3 does yield Ga(Sp) 3 if excess HSp is employed, otherwise Ga(Cl)(Spy) 2 (NEt 3) ( 6) may be isolated. The indium compound, In(Spy) 3 ( 7), may be prepared both in an analogous manner to that for compound 5, but also from the reaction of HSpy with either InCL or InCl 3 in the presence of NEt 3. In all compounds, except compound 3, the 2-mercaptopyridine acts exclusively as a chelating ligand. Reaction of Ga( t Bu) 3 with Ph 2P(S) yields [Ph 2P(S)S] 2 but only traces of the expected product [ ( t Bu) 2 Ga(μ- S 2 PPh 2)] 2 ( 8). In contrast, reaction of Ga( t Bu) 3 with HO(S)PPh 2 (E = S, O) yields the dimeric compounds [( t Bu) 2 Ga(μ- O(E)PPh 2)] 2, E = S ( 9), O ( 10) . Compound 9 exists as a mixture of head-to-head ( 9a, syn) and head-to-tail ( 9, anti) isomers due to the asymmetry of the bridging ligand. Reaction of GaCl 3 with three molar equivalents of Na(S 2PR 2)·2(H 2O), R = Me, Et, yields the tris-dithiophosphinate compounds. Ga(S 2PR 2) 3, R = Me ( 11) , Et ( 12). All new compounds have been characterized by NMR and IR spectroscopy and mass spectrometry. In addition, the molecular structures of compounds 4 and 10 have been determined by X-ray crystallography.