Preparation of half-sandwich ethylene complexes of Osmium(II)

Ethylene complexes [OsCl(η 6-p-cymene)(η 2- CH 2CH 2)L]BPh 4 (1, 2) [L = P(OMe) 3, P(OEt) 3, PPh(OEt) 2, tBuNC) were prepared by allowing the dichloro compounds OsCl 2(η 6-p-cymene)L to react with CH 2CH 2 in mild conditions (1 atm). Treatment of 1 with amine or hydrazine yielded [OsCl(p-tolyl-NH 2) (η 6-p-cymene){PPh(OEt) 2}]BPh 4 (3) or [OsCl(η 6-p-cymene)(CH 3NHNH 2){PPh(OEt) 2}]BPh 4 (4) derivatives. The vinylidene cation [OsCl{CC(H)Ph}(η 6-p-cymene){PPh(OEt) 2}] + (5 +) was also prepared from 1 and PhCCH. The complexes were characterized spectroscopically and by X-ray crystal structure determination of [OsCl(η 6-p-cymene)(η 2-CH 2CH 2){P(OMe) 3}]BPh 4 (1a). The nature of the Os-ethylene bond was investigated from a computational point of view. © 2011 Elsevier B.V. All rights reserved.