Dithiol complexes

The reaction of toluene-3,4-dithiol(3,4-dimercaptotoluene) and antimony trichloride ia acetone yields a yeUow soHd Sb2(tdt)2, where tdt is the toluene-3,4-dithiolate anionic ligand (51). With the disodium salt of maleonitnledithiol ((Z)-dimercapto-2-butenedinitrile), antimony trichloride gives the complex ion [Sb(mnt)2] , where mat is the maleonitnledithiolate anionic ligand. This complex has been isolated as a yeUow, crystalline, tetraethyl ammonium salt. The stmctures of these antimony dithiolate complexes have apparendy not been unambiguously determiaed. 

The chemistry of dithioacid and 1,1-dithiolate complexes. D. Coucouvanis, Prog. Inorg. Chem., 1970,11,233-371 (516). 

Mansour, M.A., Lachicotte, R.J., Gysling, H.J. and Eisenberg, R. (1998) Syntheses, molecular structures, and spectroscopy of gold(III) dithiolate complexes. Inorganic Chemistry, 37, 4625. 

Four-coordinate, planar iron(II)-dithiolate complexes also exhibit intermediate spin. The first example described was the tetraphenylarsonium salt of the square-planar bis(benzene-l,2-dithiolate)iron(II) dianion, (AsPh4)2[Fe(II)bdt2], which showed 5 = 0.44 mm s and AEq = 1.16 mm s at 4.2 K [157]. The electronic structure of a different salt was explored in depth by DFT calculations, magnetic susceptibility, MCD measurements, far-infra red spectroscopy and applied-field Mossbauer spectroscopy [158]. 

Winter, C. S. Oliver, S. N. Rush, J. D. Hill, C. A. S. Underhill, A. E. Third-order Optical Nonlinearities in Metal Dithiolate Complexes. In Organic Molecules for Nonlinear Optics and Photonics Messier, J., Kajzar, F., Prasad, P., Eds. NATO ASI Series E, 194 Kluwer Boston, 1991 pp 383-390. 

F.E. Inscore, R. McNaughton, B.L. Westcott, M.E. Helton, R. Jones, I.K. Dhawan, J.H. Enemark, and M.L. Kirk, Spectroscopic evidence for a unique bonding interaction in oxo-molybdenum dithiolate complexes implications for sigma electron transfer pathways in the pyranopterin dithiolate centers of enzymes. Inorg. Chem. 38, 1401-1410 (1999). 

Scheme 5 Dithiolate complexes containing cyclopentyldienyl ligands...

Fig. 2 Schematic drawing of unsymmetrical donors based on diimine-dithiolate complexes...

Dr. Herber One of the organic compounds we synthesized some years ago was a toluene dithiol complex that apparently forms a polymer, is quite stable, and produces a suitable Mossbauer spectrum at room temperature. 

A nickel disulfonato complex obtained by oxidation of a mononuclear nickel dithiolate complex... 

The use of six equivalents of dihydrogen peroxide leads to a clean conversion of the dithiolate complex to the disulfonate compound. Earlier studies on oxidation of nickel thiolates showed that oxidations with dioxygen stop at monosulfinates. Our observation and the characterization of the first chelating bis-sulfonato nickel complex formed from the direct oxidation of a mononuclear nickel dithiolate, may also provide new insight into the chemistry of sulfur-rich nickel-containing enzymes in the presence of oxygen. 

Henderson, R. K., Bouwman, E., Spek, A. L. and Reedijk, J. (1997) A unique mononuclear nickel disulfonato complex obtained by oxidation of a mononuclear nickel dithiolate complex. Inorg. Chem., 36, 4616-17. 

The second example refers to oxomolybdenum dithiolate complex [Md O(qdt)2], where qdt stands for quinoxaline-2,3-dithiolate. This complex also manifests thermal valence isomerism. Helton et al. (2001) also explain it with the change of the molybdenum oxidation state ... 

A nice example of a degenerate rearrangement has been reported for the complex pentacarbonyltungsten(0)-thioaldehyde-l,2-dithiol 177 (R = H) or the thioketone-1,2-dithiol complex 177 (R = CH3). These compounds (obtained by the reaction of silver nitrate with tetraethylammonium pentacar-bonyliodotungstate(O) in the presence of l,6,6 z -trithiapentalenes) appeared to exist as an equilibrium mixture of the two isomers 177/178 (Scheme IV.70) [83JCS(CC)289]. The symmetrically substituted 1,2-dithiol (R = CH3, R = H) displays fluxional behavior as appears by NMR spectroscopy... 

Recently, dithio-diolate ligands have been employed for construction of group 4 metal catalysts for the ROP of lactide. These metal dithiolate complexes form mononuclear species of the type [(OSSO)M(OR)2] with an octahedrally coordinated metal center. These fluxional compounds acted as highly active catalysts in the ROP of L- and rac-lactide. Hafnium complexes were also introduced as initiators for the ROP of L-lactide and rac-lactide (vide infra) in very limited cases. To our knowledge, the hafnium derivative 146 displayed the highest activity among the group 4 catalysts reported to date (complete conversion of 300 equiv. of... 

Le Narvor N, Robertson N, Weyland T, Kilbum JD, Underhill AE, Webster M, Svenstrup N, Becher J (1996) Synthesis, structure and properties of nickel complexes of 4,5-tetrathia-fulvalene dithiolates high conductivity in neutral dithiolate complexes. Chem Commun 1363-1364... 

VO(Et2NCS2)2] has discrete molecules with five-coordinate square pyramids, with thf oxygen at the apex with d(V=0) = 1.59 A.667 The vanadium atom lies approximately 0.75 above the plane of the four sulfur atoms and the average V—S distance is 2.402 A, shorte than for most vanadium dithiolate complexes 667 IR, electronic and ESR spectra are consisten... 

TTie diamagnetic dithiolate complexes rrans-[Mo(SR)2(diphos)2] are reversibly oxidized to the Mom species and the E°xn values for R = QH4X-4 (X = Me, H, NH2, OMe, F, Cl) show a linear dependence upon the Hammett o function for X, as do the 31P chemical shifts of these compounds.81... 

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