Multimetallic arrays: Symmetrical bi-, tri- and tetrametallic complexes based on the group 10 metals and the functionalisation of gold nanoparticles with nickel-phosphine surface units

Abstract

Homobimetallic complexes of nickel, palladium and platinum, [(L₂M)₂(S₂CNC₄H₈NCS₂)]²⁺, are formed on reaction of the piperazine bis(dithiocarbamate) linker, KS₂CNC₄H₈NCS₂K, with [MCl₂L₂] (M = Ni, L₂ = dppe, dppf; M = Pd, L₂ = dppf; M = Pt, L = PEt₃, PMePh₂, PPh₃, L₂ = dppf). [{Pd(C,N-C₆H₄CH₂NMe₂)}₂(S₂CNC₄H₈NCS₂)] can be obtained in the same way. On reaction of [MCl₂L₂] (M = Pd, Pt) with the zwitterion S₂CNC₄H₈NH₂, a symmetrisation process occurs to yield a mixture of the complexes [M(S₂CNC₄H₈NH₂)L₂]²⁺ and [(L₂M)₂(S₂CNC₄H₈NCS₂)]²⁺. However, the monometallic complexes [L₂Ni(S₂CNC₄H₈NH₂)]²⁺ (L₂ = dppe, dppf) and [(L₂Ni)₂(S₂CNC₄H₈NCS₂)]²⁺ can be prepared without ready symmetrisation. Starting from the previously reported [(dppm)Ru(S₂CNC₄H₈NH₂)]²⁺, the heterotrimetallic products [(dppm)Ru(S₂CNC₄H₈NCS₂)M(dppf)]²⁺ (M = Pd, Pt) can be prepared without symmetrisation occurring. The crystal structures of five complexes are reported. The metalla-dithiocarbamate complexes [L₂Ni(S₂CNC₄H₈NCS₂)] (L₂ = dppe, dppf) were used to functionalise the surface of gold nanoparticles by the displacement of a citrate shell to yield NiAu and FeNiAu materials.