FORMATION OF 1,3-DIENE COMPLEXES UPON PROTONATION OF CYCLOPROPYLCARBYNE COMPLEXES

Addition of HCl to the cyclopropylcarbyne complexes Cp[P(OMe)3]2Mo=C(CRCH2CH2 [R = H, D, Me (1, 1-d, 3)] results in formation of the diene complexes Cp[P(OMe)3](CI)Mo(eta4-CH2=CRCH=CH2) [R = H, D, Me (5, 5-d, 6a, 6b)]. The metal hydride Cp[P(OMe)3]2Cl2-Mo(H) (4) is the major product formed in the reaction of HCI with 1 and 1-d, though none is formed upon reaction with 3. Reaction of 1 with HBF4.Et2O results in formation of the hydrido carbyne complex [Cp(H){P(OMe)3}2Mo=C(C-C3H5)]+BF4- (7) which eventually rearranges to the diene complex [Cp{P(OMe)3}2Mo(eta4-CH2=CHCH=CCH2)]+BF4- (8). The diene complex Cp[P(OMe)3](Cl)MO(eta4-CH2=CMeCH=CH2) (6b) has been isolated and a crystal structure obtained: P2(1)/n, a = 9.876(2) angstrom, b = 12.157(3) angstrom, c = 13.372(2) angstrom, beta = 91.62(2)-degrees, V = 1604.9(6) angstrom3; Z = 4; R = 3.77%; R(w) = 4.60% for 2162 reflections F > 4.0sigma(F).