Chalcogenido complexes

Meanwhile, Parkin and his co-workers have also reportedthe synthesis of a series of terminal chalcogenido complexes of germanium 66, 67, and 68 (Scheme 20).42 X-ray structural analyses of 66, 67, and 68 revealed that they have unique germa-chalcogenourea structures stabilized by the intramolecular coordination of nitrogen atoms. The central Ge-X (X = S, Se, Te) bond of 66, 67, and 68 should be represented by a resonance structure, Ge+ - X- —>- Ge=X, because their bond... 

Similarly, stannanethione 125 and stannaneselone 127 kinetically stabilized by Tbt and Ditp groups have 119Sn chemical shifts of 531 and 440 ppm, respectively. Recently, Parkin et al. have reported the synthesis of stable terminal chalcogenido complexes of tin 150 (Scheme 38), and the chemical shifts for the central tin atom... 

Application to the Controlled Synthesis of Binary Metal Chalcogenido Complexes and Clusters... 

The reactions of electrophilic alkynes, such as DMAD (dimethyl acetylene-dicarboxylate), with metal per- and poly-chalcogenido complexes have been exploited for the synthesis of homoleptic and heteroleptic 1,2-dithiolene,... 

Note, however, that although the telluroketone [C6H4(CMe2)2CTe] is dimeric in the solid state, the monomer has been characterized spectroscopically in solution Mi-noura, M. Kawashima, T. Okazaki, R. J. Aon. Chem. Soc. 1993,115, 7019 Minoura, M. Kawashima, T. Okazaki, R. Tetrahedron Lett. 1997, 38, 2501. For a review of terminal chalcogenido complexes, see Kuchta, M. C. Parkin, G. Coord. Chem. Rev. 1998, 176, 323. 

Reaction of germylenes with elemental chalcogens (sulfur, selenium, tellurium) also allowed the synthesis of stable >Ge = E species. This was first exemplified by the isolation of terminal chalcogenido complexes of germanium 170152 and 171-173153 (Scheme 34). Stabilization in these cases is achieved by intramolecular complexation of the metal atom by Lewis bases. 

All these examples illustrate the wide range of structural variety and their fascinating relationship with the delicate excited state properties in these polynuclear gold(I) chalcogenido complexes. 

Parkin, General, Terminal Chalcogenido Complexes of the Transition Metals 47 1... 

The homoleptic, bis(trispyrazolylborate)titanium(ll) complex, Tp2Ti (Tp = trispyrazolylborate 203), has been prepared by reaction of 2 equiv. of KTp with TiCl2(TMEDA) (TMEDA = Ar,Ar,Ar, A -tetrarncthylcthylcncdiarninc).122 The dark red, paramagnetic compound has idealized /)v/ symmetry in the solid state and is easily oxidized to the corresponding Ti(m) derivative both electrochemically and chemically with AgPF, 204. Two-electron oxidation to Ti(rv) chalcogenido complexes has been accomplished with pyridine-N-oxide as well as with elemental sulfur and selenium (205, Scheme 31). 

Trnka, T. Parkin, G. A survey of terminal chalcogenido complexes of the transition metals trends in their distribution and the variation of their M=E bond lengths Polyhedron 1997, 16, 1031-1045. 

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