Copper dithiolenes

A number of complexes of copper with 1,1-dithiolenes are known they are interesting, inasmuch as they form (1) polynuclear species, e.g., [Cu4(i-mnt)3]2 . Recently, a copper(III) complex of 1,1-dicarboeth-oxy-2-ethylenedithiolate (DED ) was prepared (375) by oxidation of aqueous solutions of K2[Cu(DED)2] with a 10-15% excess of Cu(II) or H202, and of (BzPh3P)2[Cu(DED)2] with I2. The possibility of this system as a model for the Cu "/Cu. system in n-galactose oxidase has been pointed out. Lewis and Miller (113) also prepared M[Cu(S2C CHN02)2] (M = Cu, or Zn) and Cu[Cu S2C C(CN)2 2], and found that they are effective insecticides. 

Synthesis. The first known thiophene-based metal dithiolenes were reported by Gol dfarb and Kalik in 1968." These consisted of the nickel and copper complexes of 2,3-thiophenedithiolate produced from ethyl 3-thienyl sulfide as shown in Scheme 1. Both complexes were reported as black, high melting solids and were thought to be the neutral bis(2,3-thiophenedithiolate) species. 

Also related to their redox activity, a series of copper and manganese bis(dithiolene) complexes has been reported to catalyze the oxidative polymerization of 2,6-dimethylphenol to poly[oxy(2,6-dimethyl-1,4-phenylene)]... 

The involvement of copper to protect the dithiolene sulfurs is unclear. ... 

In addition, it was shown that active Moco (54) can be synthesized in vitro by ligation of molybdate to MPT without the requirement of any additional factors. Under the molybdate concentrations used in the assay (>5 mmoll ), the involvement of MoeA and MogA was not required for generating the active form of Moco. This shows that the ATP-dependent activation of MPT and molybdenum is only required under physiological concentrations and that in vitro copper is not required to protect the dithiolene group of MPT. Apart from the possibility that copper is not physiologically relevant for Moco biosynthesis, it remains possible that there is a difference between prokaryotes and eukaryotes in the requirement of copper during Moco biosynthesis. ... 

Models for monodithiolene molybdenum species related to xanthine oxidase and aerobic CODH have been described, e.g. [Mo(S2CgH4)02(SR)] [143]. The synthesis of related species with terminal sulfido ligands would enable assembly of the indicated (dithiolene)Mo02S-CuSR ensembles. The interaction of M0S4 and Cu has received considerable study, motivated by interest in the ability of dietary Mo to inhibit copper uptake in ruminants [144]. Bi-, tri-, tetra-, or higher nuclearity Cu-Mo clusters result from the reaction of MoS and Cu" in the presence of tertiary phosphines, amines, or cyanide [144]. 

Increasing attention has been devoted in recent years to systems based on titanium dioxide (the most important photocatalytic oxide) containing surface copper species or well defined copper complexes. " This system can be used for the photocatalytic decomposition of chlorine-containing organic molecules or reduction of bis-dithiolene complexes. The role of EPR is important for following the one-electron photoinduced redox processes that occur in these reactions. " " ... 

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