Diselenides metal complexes

Thiocarbonyl and selenocarbonyl metal complexes are generally prepared from carbon disulfide, CS2 thiophosgene, CSCI2 and carbon diselenide, CSc2, as well as from transition metal complexes such as metal carbonyls. Commonly, triphenyl-phosphine is utilized to eliminate sulfur or selenium ... 

A number of selenium and tellurium compounds of the presently discussed metals show a quite different behavior from the Fe-S system. Iron and selenium form two compounds FeSe with a broad stoichiometry range and FeSe2 with a much narrower composition field. Below 400 the non-stoichiometric Fei xSe exists by creation of iron vacancies and can have compositions lying between FeySes and Fe3Se4. At low temperatures there exist two phases an a (PbO type) and a f) (NiAs type) phase. The crystal sUiicture of the diselenide, FeSe2, is an orthorhombic, C18 (marcasite) type. In the Fe-Te system, the defect NiAs structure is found at a composition close to FeTei.s, as about one-third of the Fe atoms are missing. At compositions around FeTe the behavior is complex, and the f)-phase has the PbO structure (like FeSe) but with additional metal atoms (i.e., FeuTe). 

A A -coordi nation was found in the zinc complex of 2,2 -dipyridyl diselenide, [ZnLCl2].214 The tridentate ligand 6-(2-aminophenyl)-2,2 -bipyridine contains two pyridyl and one aniline donor ligand to form a complex of the form [ZnL2]2+. The X-ray structure shows a distorted octahedral metal center with each ligand twisting from planar to accommodate the meridional binding.215... 

Various reducing agents have been used for the generation of selenolates from diselenides or selenocyanates. Alkali metals M (M = Li, Na, K)149,150 or alkali hydrides MH (M = Li, Na, K)151,152 can generate the corresponding selenolate anions such as 80 these are more reactive than the borane complexes of type 77 (Scheme 15). Diaryl diselenides are easier reduced than dialkyl diselenides, but the mechanism for the reduction of selenocyanates is complex and can lead to either diselenides or selenolates.153,154... 

The manganese carbonyl disulfide complex (12) inserts various metal fragments into the S-S bond (Scheme 8). On the other hand, Me2S inserts into the Mn-Mn bond and tertiary phosphines substitute CO ligands. Heterobimetallic disulfides and diselenides analogous to (12) have been... 

The synthesis of the zinc complex 115 according to Scheme 3 presents an efficient alternative to the previous method based on reduction of carbon diselenide by sodium metal <1990JCD115>. Compounds 22, 98-101, and 116 containing either (2-methoxycarbonyl)ethyl or 2-cyanoethyl as thiolate protecting groups are versatile compounds for the synthesis of a large selection of functionalized tetraselenafulvalenes via the (1) base-promoted deprotection and (2) thiolate alkylation protocol. 

The reaction of uranium metal with polyselenides in molten potassium polyselenide generates an interesting molecular diselenide complex K4[U(r/ -Se2)4], containing a discrete U( 7 -Se2)4 anion. 

Benzeneselenol, a representative selenol, is a colorless liquid of greater acidity than benzenefhiol [pK = 5.9 (PhSeH) 6.5 (PhSH)]. Benzeneselenol is usually synfhesized by the reaction of phenylmagnesium bromide with metallic selenium then quenching wifh aqueous hydrochloric acid [10]. Similar hydrolysis of the sodium phenylseleno(triethoxy)borate complex prepared by fhe reduction of diphenyl diselenide wifh sodium borohydride is a convenient alternative [11]. 

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