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.

Polyfunctionalised Nanoparticles Bearing Robust Gadolinium Surface Units for High Relaxivity Performance in MRI

“…Since 2008, we have focused on the functionalisation of gold nanoparticles (GNPs) with transition metal units . Much of this work has focused on the use of dithiocarbamate (R 2 NCS 2 − ) tethers rather than the usual thiol(ate) or disulfide attachment methodologies.…”

“…Addition of K 2 CO 3 followed by carbon disulfide leads to the formation of the expected dithiocarbamate moiety (compound 7), in line with our previous studies on piperazine-based dithiocarbamatec omplexes. [16,17,26] As discoveredi nt hese earlier studies, the long-term stability of 7,both in solution and in the solid state, was found to be significantly worse than that of 6, so compound 7 was always generated in situ when desired, but not isolated. High-resolution mass spectrometry experimentsn evertheless confirmed the generationo f7 (m/z 702.1025).…”

“…Compound 6 was found to be stable for months as a solid and could be prepared and stored on a large scale (>1 g). Addition of K 2 CO 3 followed by carbon disulfide leads to the formation of the expected dithiocarbamate moiety (compound 7 ), in line with our previous studies on piperazine‐based dithiocarbamate complexes . As discovered in these earlier studies, the long‐term stability of 7 , both in solution and in the solid state, was found to be significantly worse than that of 6 , so compound 7 was always generated in situ when desired, but not isolated.…”

“…Since 2008, we have focusedo nt he functionalisation of gold nanoparticles (GNPs) with transition metal units. [14][15][16][17][18] Much of this work has focusedo nt he use of dithiocarbamate (R 2 NCS 2 À )tethers rather than the usual thiol(ate) or disulfide attachment methodologies. Competition experiments by us [19] and others [20] have shown that dithiocarbamates are able to displace thiol(ate)s from the surface of the nanoparticle, but not vice versa.…”

Metal-dithiocarbamate complexes: chemistry and biological activity

“…An exciting new development in the area of golddithiocarbamate chemistry is the stabilization of gold nanoparticles by chelating dithiocarbamate ligands [92][93][94][95][96][97]. These are extremely easy to prepare, show good stability and allow decoration of the nanoparticles with a range of different functional groups.…”