Synthesis and reaction of the novel complex [AsPh4][OsCl5(H2O)]. X-ray structure analysis of [AsPh4][OsCl5(H2O)]center dot 2EtOH and [AsPh4][OsCl5(EtOH)]center dot EtOH

The synthesis and characterization of the,anionic mononuclear and homobinuc lear osmium complexes [AsPh4][OsCl5L]. xEtOH [L = H2O, x = 2 (9); L = EtOH, x = I (10a); L = py, x = 0 (10b)] and [AsPh4](2)[Cl5Os(pyz)OsCl5] (12) (py z = pyrazine) are described. Upon reduction in a chloride-containing medium , OsO4 (1) affords the osmium(IV) species [OsCl5(H2O)](-) (2), which could be isolated by extraction with n-tributyl phosphate (TBP). Complex 9 is the first fully characterized chloroaquo complex of Os(TV). This complex is an effective starting material for the preparation of novel species, such as 10a, 10b, and 12. The X-ray structures of 9 and 10a were determined. Both c ompounds crystallize in the monoclinic space group P2(1)/n. 9: C28H34AsCl5O 3Os, a = 10.910(4) Angstrom, b = 17.127(5) Angstrom, c = 17.555(7) Angstrom , beta = 103.77(2)degrees V = 3186(2) Angstrom (3), and Z = 4. 10a: C(28)H( 32)AsCl(5)O(20)s, a = 20.7762(2) Angstrom, b = 17.3939(1) Angstrom, c = 17. 1477(3) Angstrom, beta = 103.635(1)degrees, V = 3123.45(8) Angstrom, and Z = 4. Complexes 9 and 10a crystallize with two and one molecule of EtOH and are bonded via hydrogen bridges to the H2O and EtOH ligand in 9 and 10a, re spectively.