Arsenates complexes

A novel high-yielding synthetic route to 3,5-disubstituted-l,2,4-thiadiazoles 104 has been reported which involves the reaction of nitriles with the arsenic complex S AsFg in liquid SO2 (Equation 29) <1999CC1801>. 

Gao, Y. and Mucci, A. (2001) Acid base reaction, phosphate and arsenate complexation, and their competitive adsorption at the surface of goethite in 0.7M NaCl solution. Geochimica et Cosmochimica Acta, 65(14), 2361-78. 

Arsenic Complexes Based on Ligands with Chalcogen Donor Atoms... 

Inorganic arsenic complexes based on oxygen ligands is scarce. Simple esters of arsenic acid, As(0)(0R)3 (R = Me, Ft, n-Pr, n-Bu, CeHn) have tetragonal structures. Reaction of the diol ligand 2,4-dimethyl-2,4-pentanediol with AsCfr affords an arsenic chloride complex in which the As atom is part of a six-membered ring (37). ... 

The chemistry of inorganic arsenic complexes with ligands that bear S donor atoms or S and O is more extensive. The chemistry of arsenic with xanthate (41), dithiocarbamate (42) and phosphorus based ligands (43) (Figure 12) has been reviewed. ... 

Homoleptic trisquelate arsenic complexes have been only stmcturally characterized with ligands (41) and (42). The complexes show mainly a distorted octahedral geometry, that is, [As(S2COMe)3] (44), or antiprismatic, that is, [As S2CN(CH2CH20H) 3] (45) (Figure 13). These... 

Mixed ligand arsenic complexes have been reported. The chloro derivatives of general formnla [AsCb S2P(OR)2 ]... 

Figure 13 Homoleptic trisquelate arsenic complexes [As(S2COMe)3] (44) and [As (S2CN(CH2CH20H) 3] (45) ...

After bromination and subseqnent hydrolysis of (53) the cationic arsenic complex (55) with arsenic in the 5+ oxidation... 

The Sb—Sb bond distances are 280 pm the Sb Sb contacts extend from 396 to 406 pm, thus being shorter than the sum of van der Waals radii ° with 440 pm. The analogous arsenic complex shows As—Asc, mean distances of 240.7 pm the As—As bond distances normally are 246.2 pm. ... 

The toxicity of Sb is a function of the water solubility and the oxidation state of the Sb species under consideration. Antimony toxicity often parallels that of arsenic, although antimony salts are less readily absorbed than arsenic. It is presumed that antimony, like arsenic, complexes with sulfhydryl groups of essential enzymes and other proteins. By analogy, antimony can uncouple oxidative phosphorylation, which would inhibit the production of energy necessary for cellular functions. Antimony s trivalent compounds are more toxic than its pentavalent compounds. 

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