Complex trans- OsCl

The formation of the first osmium hydrido(alkoxo) complex, a yellow air-stable and thermally stable hydrido(methoxo)osmium(II) complex, trans-[OsH(OMe)(Cl) (NO) (P Pr3)2] (72), by the oxidative addition of MeOH to a 16-electron complex, trans-[OsCl(NO)(P Pr3)2] (71) was briefly reported (Eq. 6.22) [51]. 

The first X-ray structure of an Os oxo complexes, trans [OsCl(O) (dcpe)2]+ (dcpe = l,2-bis(dicyclohexylphosphino) ethane), has been reported. Its formation proceeds via the activation of O2 to form [0sCl()] -02) (dcpe) 2], which then reacts with HCl gas. Although the complex [0sCl()] -02) (dcpe)2] + readily displays oxo-transfer chemistry, for example, with phosphines, the 0x0 complex frarrs-[OsCl(O) (dcpe)2]... 

In elongated H2 complexes, experimental and computational studies indicate that the 7 -H2 ligand is greatly delocalized and caimot be envisaged as a fixed, rigid unit [7]. Rapid motion of two hydrogen atoms occurs on a flat potential energy surface with a shallow minimum at the neutron-diffraction determined position of 1.2 A for trans-[OsCl(H2)(dppe)2]+. 

Salts of [0s(N02)5] have long been reported in the literature" with sodium, potassium, ammonium, magnesium, calcium, strontium and barium cations, but the anion in these salts is now known to be trflns-[0s(N0)(0H)(N02)4] ." The potassium salt, made from [OsCl ] " and excess KNO2," is a useful starting material for other nitrosyl complexes since the NO groups are easily displaced. The X-ray crystal structure of the anion is discussed below (p. 548). The anion exhibits a complex hydrolytic behaviour, alledgedly in accordance with the trans effect of the nitrosyl Ugand." ... 

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