Silver complexes arsenic ligands

Other arsenic-containing ligands reported include mixed donor species with S212 or N213,214 as the other donor atom. The ligand bis(carboxymethyl)(o-methylthiophenyl)arsine (24) contains S and As donors in a position suitable for chelation. Formation constants for its complexes with Ag1 are given in Table 30. The silver complexes of the m and p derivatives were insoluble under the conditions used and no data could be collected.212... 

Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

Tetracarbonyl cations [Cr(CO)4(L2)]+, where L2 represents arylphosphines, alkyl, or aryl phosphites, or a bidentate ligand with phosphorus or arsenic donor atoms, have been produced by both chemical and electrochemical means. However, oifly one of these complexes, namely, tra i -[Cr(CO)4(PPh3)2]+, is stable enough to be isolated as the perchlorate salt. Exposure to light and moisture produces tra i -Cr(CO)4(PPh3)2 via disproportionation. Just as easily isolated, but somewhat less sensitive, are the [Cr(CO)3(PR3)3]+ cations. " Oxidation with a silver ion or NO+ converts the /uc-(R3 = Me2Ph, (OMe)3) and mer-(R3 = (OMe)3, (OMe)2Ph, (OPh)3) complexes into Cr products with mer structures. Light and heat promote the formation of reduced wer-Cr(CO)3 (PR3)3. These tetra(carbonyl) and tri(carbonyl) cations have been the subject of ESR spectroscopy and theoretical study. 

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