Some Cu(III) dithiocarbamates

Copper Dithiocarbamates: Coordination Chemistry and Applications in Materials Science, Biosciences and Beyond

Copper dithiocarbamate complexes have been known for ca. 120 years and find relevance in biology and medicine, especially as anticancer agents and applications in materials science as a single-source precursor (SSPs) to nanoscale copper sulfides. Dithiocarbamates support Cu(I), Cu(II) and Cu(III) and show a rich and diverse coordination chemistry. Homoleptic [Cu(S2CNR2)2] are most common, being known for hundreds of substituents. All contain a Cu(II) centre, being either monomeric (distorted square planar) or dimeric (distorted trigonal bipyramidal) in the solid state, the latter being held together by intermolecular C···S interactions. Their d9 electronic configuration renders them paramagnetic and thus readily detected by electron paramagnetic resonance (EPR) spectroscopy. Reaction with a range of oxidants affords d8 Cu(III) complexes, [Cu(S2CNR2)2][X], in which copper remains in a square-planar geometry, but Cu–S bonds shorten by ca. 0.1 Å. These show a wide range of different structural motifs in the solid-state, varying with changes in anion and dithiocarbamate substituents. Cu(I) complexes, [Cu(S2CNR2)2]−, are (briefly) accessible in an electrochemical cell, and the only stable example is recently reported [Cu(S2CNH2)2][NH4]·H2O. Others readily lose a dithiocarbamate and the d10 centres can either be trapped with other coordinating ligands, especially phosphines, or form clusters with tetrahedral [Cu(μ3-S2CNR2)]4 being most common. Over the past decade, a wide range of Cu(I) dithiocarbamate clusters have been prepared and structurally characterised with nuclearities of 3–28, especially exciting being those with interstitial hydride and/or acetylide co-ligands. A range of mixed-valence Cu(I)–Cu(II) and Cu(II)–Cu(III) complexes are known, many of which show novel physical properties, and one Cu(I)–Cu(II)–Cu(III) species has been reported. Copper dithiocarbamates have been widely used as SSPs to nanoscale copper sulfides, allowing control over the phase, particle size and morphology of nanomaterials, and thus giving access to materials with tuneable physical properties. The identification of copper in a range of neurological diseases and the use of disulfiram as a drug for over 50 years makes understanding of the biological formation and action of [Cu(S2CNEt2)2] especially important. Furthermore, the finding that it and related Cu(II) dithiocarbamates are active anticancer agents has pushed them to the fore in studies of metal-based biomedicines.

Self-assembled transition metal dithiocarbamates of pyridine-3-carboxamide: synthesis, spectral characterization, thermal and biological studies

Synthesis of self assembled transition metal dithiocarbamates of pyridine-3-carboxamide by conventional as well as in situ methodology was reported. Characterization was done with a variety of spectroscopic techniques. Anticancer and antioxidant activity of ligand and its complexes is also tested.

Synthesis, characterization, molecular docking and biological studies of self assembled transition metal dithiocarbamates of substituted pyrrole-2-carboxaldehyde

A series of self assembled 3d transition metal dithiocarbamate, M(pdtc) [where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)] have been synthesized and spectroscopically characterized. The bidentate dithiocarbamate ligand Na2pdtc (Disodium-1,4-phenyldiaminobis (pyrrole-1-sulfino)dithioate) was prepared by insertion reaction of carbondisulfide with Schiff base, N,N'-bis-(1H-pyrrol-2-ylmethylene)-benzene-1,4-diamine (L1) in basic medium. The simple substitution reaction between the metal halide and Na2pdtc yielded the title complexes in moderate yields. However, the in situ procedure gives high yield with the formation of single product as evident by TLC. Elemental analysis, IR, (1)H and (13)C NMR spectra, UV-vis., magnetic susceptibility and conductance measurements were done to characterize the complexes, M(pdtc). All the evidences suggest that the complexes have tetrahedral geometry excepting Cu(II) which is found to be square planar. A symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the complexes. The conductivity data show that the complexes are non-electrolyte in nature. The anti-oxidant activity of the ligand, Na2pdtc and its transition metal complexes, M(pdtc) have been carried out using DPPH and Cu(pdtc) was found to be most effective. The anti-microbial activity of the Na2pdtc and M(pdtc) complexes have been carried out and on this basis the molecular docking study of the most effective complex, Cu(pdtc) has also been reported.