Reactivity of the imine-vinylidene complexes OsCl2(=C=CHPh) (NH=CR2)((PPr3)-Pr-i)(2) [CR2 = CMe2, C(CH2)(4)CH2]

The reactivity of the imine- vinylidene compounds OsCl2(=C=CHPh)(NH=CR2)((P Pr3)-Pr-i)(2) [CR2 = CMe2 (1), C(CH2)(4)CH2 (2)] toward amines, (BuLi)-Bu-n , and HBF4 has been studied. Complexes 1 and 2 react with triethylamine and diallylamine to give equilibrium mixtures of the corresponding starting ma terials and the five-coordinate azavinylidene derivatives OsCl(=N=CR2)(=C=C HPh)((PPr3)-Pr-i)(2) [CR2 = CMe2 (3), C(CH2)(4)CH2 (4)], which are obtained as pure microcrystalline solids by reaction of 1 and 2 with (BuLi)-Bu-n. T he structure of 3 in the solid state has been determined by an X-ray diffra ction study. The geometry around the metal center could be described as a d istorted trigonal bipyramid with apical phophines and inequivalent angles w ithin the Y-shaped equatorial plane. The azavinylidene group coordinates in a bent fashion with an Os-N-C angle of 157.2(6)degrees. Complexes 1 and 2 also react with allylamine and aniline, The reactions initially give 3 and 4. However, the amount of these compounds decreases by increasing the react ion time. This decrease is accompanied with the formation of mixed amine-ph osphine compounds OsCl2(=C=CHPh)(NH= CR2)(NR2R ')((PPr3)-Pr-i) [R ' = allyl ; CR2 = CMe2 (5), C(CH2)(4)CH2, (6). R ' = Ph; CR2 = CMe2 (7), C(CH2)(4)CH2 (8)]. The structure of 5 in the solid state has been also determined by an X-ray diffraction study. In this case, the geometry around the osmium atom can be rationalized as a distorted octahedron with the amine and phosphine ligands mutually trans disposed and the chlorine ligands mutually cis disp osed. The X-ray analysis also shows that the NH-hydrogen atoms of the amine and the chlorines are involved in intra- and intermolecular HCl hydrogen b onding. The reactions of 1 and 2 with HBF4. OEt2 afford the carbyne derivat ives [OsCl2(equivalent to CCH2Ph)(NH=CR2)((PPr3)-Pr-i)(2)] [BF4] [CR2 = CMe 2 (9), C(CH2)(4)CH2 (10)]. Both 1 and 2 lose the imine ligand to give OsCl2 (=C=CHPh)((PPr3)-Pr-i)(2) (11) in toluene under reflux.