Vinyliden-Uebergangsmetallkomplexe XXXVIII. Alkin-, Alkinyl-, Vinyliden-, Allenyliden- und Benzyl-Rhodiumkomplexe mit dem Phosphinoether iPr2PCH2CH2OMe als ein- und zweizaehnigen Liganden

Article abstract of DOI:10.1016/0022-328X(95)05784-M

The monomeric four-coordinate rhodium(I) compound (L=i-Pr2PCH2CH2OMe) (1) reacts with terminal alkynes HC<*>CR (R=t-Bu, Tol, CH(Ph)OH, C(Ph2)OH, C(i-Pr)2OH, C(Me)2Oh) to give the vinylidene complexes trans- (5-10) as the final products.Whereas for R=C(Ph)2OH, the stepwise conversion of the initially formed square-planar alkyne derivative 2 to the octahedral alkynyl(hydrido)compound 3 and further to the vinylidene complex 5 has been confirmed, for R=C(i-Pr)2OH a complete rearrangement of the isolated compound CR)Cl(K(P)-L)(K²(P,O)-L)> (4) to he vinylidenerhodium isomer 6 could not be acheieved.The abstraction of water from 10 (R=C(Me)2OH) induced by catalytic amounts of CF3CO2H leads to the formation of the vinylvinylidenerhodium(I) compound trans- (11); in contrast, the corresponding reaction of 5 (R=C(Ph)2OH with acidic Al2O3 yields the allenylidene complex trans- (12).The η³-benzylrhodium(I) compounds 3-CH2C6H4-4-R)L2> (14, 15), which are prepared from 1 and Grignard reagents 4-RC6H4MgCl (R=H, CH3), react with CO to give the η¹-benzyl derivatives 1-CH2C6H4-4-R)(CO)L2> (16, 17).The reaction of 14 with HC<*>CC(i-Pr)2OH yields the bis(alkenyl)hydridorhodium(III) comopound CR)2L2> (R=C(i-Pr)2OH) (20), the tsructure of which has been determined by X-ray crystallography.While compound 14 reacts with HC<*>CC(Me)2OH under an ethene atmosphere to give trans--C(Me)2OH)(C2H4)L2> (21), on teratment of 14 with HC<*>CTol in the presence of HBF4 the cationic complex BF4 (22a) is obtained.The corresponding PF6 salt 22b is prepared from PF6 and L.Keywords: Rhodium complexes; Vinylidene complexes; Alkyne complexes; Allenylidene complexes; Phosphine, functionalized; Hydrido complexes