Ferrocene-Functionalized Cu(I)/Ag(I) Dithiocarbamate Clusters

A series of compounds, namely, [Cu-8(mu(4)-H){S(2)CNMeCH(2)Fc}(6)](PF6) (1), [Cu-7(mu(4)-H) {S(2)CN(i)PrCH(2)Fc}(6)] (2), [Cu-3{S2CN(Bz) (CH(2)Fc)}(2)(dppf)(2)](PF6) (3), and [Ag-2{S2CNMe(CH(2)Fc)}2(PPh3)(2)] (4) (dppf = 1,1'-bis(diphenylphosphino)ferrocene), supported by multiferrocene assemblies, were synthesized. All the compounds were characterized by H-1 NMR, Fourier transform infrared, elemental analysis, and electrospray ionization mass spectrometry techniques. Single-crystal X-ray structural analysis revealed that 1 is a monocationic octanuclear Cu-I cluster and that 2 is a neutral heptanuclear Cu-I cluster with tetracapped tetrahedral (1) and tricapped tetrahedral (2) geometries entrapped with an interstitial hydride, anchored by six ferrocene units at the periphery of the core. Compounds 3 and 4 comprise trimetallic Cu-I and dimetallic Ag-I cores enfolded by four and two ferrocene moieties. Interestingly both chelating and bridging modes of binding are observed for dppf ligand in 3. Further the formation and isolation of polyhydrido copper clusters [Cu28H15{S(2)CN(i)PrCH(2)Fc}(12)](PF6) (5) and [Cu28H15{(S2CNBu2)-Bu-n}(12)](PF6) (7), stabilized by bulky ferrocenyl and n-butyl dithiocarbamate ligands, was demonstrated. They are readily identified by H-2 NMR studies on their deuterium analogues, [Cu28D15{S(2)CN(i)PrCH(2)Fc}(12)](PF6) (6) and [Cu28D15{(S2CNBu2)-Bu-n}(12)](PF6) (8). Though the structure details as well as spectroscopic characterizations of 5 are yet to be investigated, the compound 7 is fully characterized by variety of spectroscopy including single-crystal X-ray diffraction. The cyclic voltammetry studies for compounds 1, 2, and 4 display irreversible redox peaks for Fe2+/Fe3+ couple wherein the reduction peaks are not well-resolved due to some adsorption of the complex onto the electrode surface.