文摘
Reactions of the transition metal halide complexes [MXL<sub>2sub>(Cp)] (M = Fe, X = I, L<sub>2sub> = dppe; M = Ru, X = Cl, L = PPh<sub>3sub>; M = Os, X = Br, L = PPh<sub>3sub>; Cp = η-C<sub>5sub>H<sub>5sub>) with the alkynol HC≡CCH(OH)(Fc) (1) (Fc = ferrocenyl) in the presence of TlBF<sub>4sub> gave the monosubstituted allenylidene complexes [M(C═C═CHFc)L<sub>2sub>(Cp)][BF<sub>4sub>] (2a: M = Ru, L = PPh<sub>3sub>; 3: M = Fe, L<sub>2sub> = dppe; 4: M = Os, L = PPh<sub>3sub>). Similarly, the reaction of 1 with [RuCl(PPh<sub>3sub>)<sub>2sub>(Cp)] and NH<sub>4sub>PF<sub>6sub> in methanol gave [Ru(C═C═CHFc)(PPh<sub>3sub>)<sub>2sub>(Cp)][PF<sub>6sub>] (2b). These highly colored compounds were characterized by spectroscopic and electrochemical techniques and in the case of 2b by a single-crystal X-ray structure determination. Cyclic voltammetry in MeCN in the presence of [<sup>nsup>Bu<sub>4sub>N][ClO<sub>4sub>] at 100 mV·s<sup>−1sup> shows a reversible ferrocenyl-based one-electron oxidation, in addition to irreversible oxidation and reduction processes. The NMR spectra of 2b show complex behavior at low temperature, attributed to temperature-dependent chemical shifts and correlated motions of the allenylidene ligand and the ferrocenyl substituent.