Sulfur and Selenium-containing

Complexes with Sulfur- and Selenium-containing Ligands 493... 

The detection of metal-binding proteins, especially of Cd- and Hg-binding metallothioneins or of the merR protein, induced numerous studies of model compounds of Cd and Hg with more or less simple sulfur- and selenium-containing ligands. 

Sliwka HR. 1999. Conformation and circular dichroism of P,P-carotene derivatives with nitrogen-, sulfur-, and selenium-containing substituents. Helvetica ChimicaActa 82(2) 161-169. 

In the above-described displacement reactions (Sh2) of sulfur- and selenium-containing compounds, the mechanism could either be a synchronous or a stepwise process (Scheme 4.2). Thus, in the Sh2 stepwise mechanism an intermediate sulfuranyl or selenyl radical is formed, followed by a-cleavage [56]. Based on competitive studies, a stepwise process was suggested to occur in the reaction of (TMS)3Si radical with -decylphenylselenide [43]. On the other hand, ab initio calculations supported the synchronous process and the same observations were explained in terms of an overall reversible reaction [57]. 

Complexes of group VIB elements with sulfur or selenium donor atoms are mainly concerned with complexes of selenium(II), tellurium(II) and tellurium(IV). The structural chemistry of complexes of selenium and tellurium with sulfur- and selenium-containing ligands has been well reviewed in the recent past.11... 

There has been a great deal of interest in recent years in photoelectron spectroscopy (PES) of the isomeric A,B-diheteropentalenes containing sulfur, selenium and nitrogen. This technique has offered for the first time direct experimental evaluation of the ionization energies of the valence electrons. The sulfur- and selenium-containing heteroaromatics appear to be the class most investigated by PES. The ionization potentials of various A,B-diheteropentalenes, are presented in Table 3. 

The chalcogene heterocycles have been used as stable precursors for sulfur-and selenium-containing hetero-l,3-dienes in cycloaddition reactions 3//-1,2,4-Thiaselenazoles are a convenient source of 4,4-bis(trifluoromethyl)-l-thia-3-aza-buta-l,3-dienes, and 3H-diselenazoles are a convenient source of 4,4-bis(trifluoromethyl)-l-selena-3-azabuta-l,3-dienes as well as bis(tnfluoro-methyl)-subsbtuted mtnle ylides [137]... 

The structure of 881 was proved by x-ray diffraction [193]. The possibility of carrying out these syntheses may be explained as due to the sufficently high stability of sulfur-and selenium-containing azomethines within a heterocyclic series, in comparison with their aromatic analogues (compare the data of Sec. 3.5.2.1), which is related to the existence of 471 as the aminomethylene form b [15,194-197]. 

J.S. Murray et al., Simultaneous a-hole and hydrogen bonding by sulfur- and selenium-containing heterocycles. Int. J. Quantum Chem. 108, 2770-2781 (2008)... 

The last step in the synthesis of the sulfur- and selenium-containing psoralen analogues (174) (7/7-thieno[3,2- ][l]benzothiopyran-7-one, 7//-seleno[3,2-/][l]benzothiophen-7-one, 2//-selenolo [3,2- ][l]benzothiopyran-2-one, and 7//-selenolo[3,2-g][ 1 ]benzoselenopyran-7-one) was the poly-phosphoric acid silyl ether (PPSE)-mediated cyclization of benzol-thiophenes or selenophenes shown in Equation (76) <92H(34)lli9>. 

Anodic Oxidation of Sulfur- and Selenium-Containing Compounds... 

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