(ETA-1-ACYL)TITANIUM COMPLEXES PREPARED BY THE CARBONYLATION OF 1-OXA-5-TITANACYCLOPENTANES

Carbonylation of 1-oxa-5-titanacyclopentanes Cp*2 activated TiOCH(R)CH2CH2 (3: a, R = CH3; b, R = CH2CH3; c, R = CHMe2; Cp* = pentamethylcyclopentadienyl) in toluene at room temperature under atmospheric pressure of CO afforded Cp*2 activated TiOCH(R)CH2CH2CO (4: a, R = CH3 (81%); b, R = CH2CH3 (77%); c, R = CHMe2 (81%)) whose structures have been characterized by spectral data and X-ray analysis. X-ray structure determination of 4c revealed that it has a novel eta-1-acyltitanium structure [space group P2(1)/n with cell constants a = 17.874 (4) angstrom, b = 16.170 (4) angstrom, c = 8.580 (1) angstrom, and beta = 92.69 (1)-degrees, V = 2482.4 (9) angstrom3 (2544 reflections, R = 0.060)]. Reaction of 3 with isocyanide gave the iminoacyl complexes Cp*2 activated TiOCH(R)CH2CH2C(NCMe3) (6: a, R = CH3; b, R = CH2CH3, c R = CHMe2). The molecular structure of 3c [space group P2(1)/a with cell constants a = 18.529 (3) angstrom, b = 16.308 (2) angstrom, c = 8.547 (1) angstrom, and beta = 111.24 (1)-degrees, V = 2407.3 (6) angstrom3 (1949 reflections, R = 0.051)] has also been determined by X-ray crystallography.