Synthesis, coordination chemistry, and metal complex reactivity of (dimethylamino)methyl-substituted triarylphosphanes; X-ray study on [AuCl(PPh3 − nArn)] (Ar = 1-C6H3(CH2NMe2)2-3,5, n = 1, 3; Ar = 1-C6H4(CH2NMe2)-4, n = 3)

The synthesis of the first series of 4-mono and 3,5-bis(dimethylamino)methyl-functionalized triarylphosphanes of the general formula PPh3 − nArn (Ar = 1-C6H3(CH2NMe2)2-3,5 (NC(H)N), n = 1 (ligand 2) or n = 3 (ligand 4); Ar = 1-C6H4(CH2NMe2)-4 (NC(H)), n = 3 (ligand 7)) is described. These phosphanes were used for the construction of complexes of the form [AuCl(P)] and [PtCl2(P)2]. In these complexes selective coordination of phosphorus to the metal ion is observed. The 31P NMR data show the formation of cis-Pt complexes, even in the case of triarylphosphane 4, which features a tris{3,5-bis(dimethylamino)methyl} substitution pattern. The structure of the gold complex of mono-3,5-functionalized triarylphosphane 2 in the solid state shows a striking resemblance to the structure of the corresponding complex [AuCl(PPh3)]. The solid-state structure of the AuCl complex of tris-4-functionalized ligand 7 differs from that of [AuCl(PPh3)] in the sign of the torsion angles. The amine functionalities in this class of gold compounds could be reacted selectively with either acid (HCl, H3PO4) to generate ammonium salts or with an alkylating agent (benzyl bromide) to afford benzyl ammonium salts, without the violation of the Au–P bond.