A thiosemicarbazone ligand functionalized by a phosphinegroup: Reactivity toward coinage metal ions

Abstract

The reactivity of the phosphino-thiosemicarbazone ligand 2-(2-(diphenylphosphino)benzylidene)-N-ethylthiosemicarbazone (HLPEt) toward M(I) halides (M = Cu, Ag, Au) was studied. The complexes obtained, with formulae [Cu(HLPEt)₂]Br (1), [Cu(HLPEt)₂]I·2H₂O (2), [Ag(HLPEt)(LPEt)]·3H₂O (3), [Au₂(HLPEt)₂Cl]Cl·CH₃OH (4) were satisfactorily characterized by elemental analysis, IR, ESI and ¹H/³¹P NMR. Moreover, we have obtained the crystal structure of the ligand HLPEt and its sulfide oxidized form HLP(S)Et, which represents a new case of desulfurization process in thiosemicarbazone ligands. In addition, we present the crystal structure of the complexes 1 + H₂O + 3MeOH and [Au₂(HLPEt)₄Cl]Cl·3CH₃OH (5), together with their interesting crystal packing. The complex 5 is an interesting case of a pseudo-chloronium gold(I) complex. The ligand HLPEt and the complexes 3 and 4 display intense luminescence at room temperature.