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

A series
of compounds, namely, [Cu8(μ4-H)­{S2CN­MeCH2Fc}6]­(PF6) (1), [Cu7(μ4-H) {S2CNiPrCH2Fc}6] (2), [Cu3{S2CN­(Bz) (CH2Fc)}2(dppf)2]­(PF6) (3), and [Ag2{S2CNMe­(CH2Fc)}2(PPh3)2] (4) (dppf = 1,1′-bis­(diphenylphosphino)­ferrocene),
supported by multiferrocene assemblies, were synthesized. All the
compounds were characterized by 1H 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 CuI cluster and
that 2 is a neutral heptanuclear CuI 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 CuI and
dimetallic AgI 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{S2CNiPrCH2Fc}12]­(PF6) (5) and [Cu28H15{S2CNnBu2}12]­(PF6) (7), stabilized
by bulky ferrocenyl and n-butyl dithiocarbamate ligands,
was demonstrated. They are readily identified by 2H NMR
studies on their deuterium analogues, [Cu28D15{S2CNiPrCH2Fc}12]­(PF6) (6) and [Cu28D15{S2CNnBu2}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.