Unexpected Formation of Ferrocenyl(vinyl)benzoquinoline Ligands by Oxidation of an Alkyne Benzoquinolate Platinum(II) Complex

Oxidation of [Pt­(bzq-κN,κC10)­(C6F5)­(η2-HCCFc)] (1) with PhICl2 and I2 affords the unusual halideferrocenyl­(vinyl)­benzoquinoline PtII derivatives [Pt­{bzq-κN-η2-CHC­(X)­Fc}­(C6F5)­X] (X = Cl (4a), I (4b)), arising from C–X and C–C coupling processes, together with small amounts of the corresponding PtIV products [{Pt­(bzq-κN,κC10)­(C6F5)­X­(μ-X)}2] (X = Cl (5a), I (5b)), respectively. Complexes 4 are very stable but they undergo easy displacement reactions with PPh3, yielding trans-[Pt­(C6F5)­X­(PPh3)2] and the corresponding new functionalized (vinyl)­benzoquinoline ligands [(Z)-bzq-CHC­(X)­Fc] (X = Cl (6a), I (6b)). The dinuclear PtIV derivatives 5 are alternatively obtained in high yield by oxidation of the solvate [Pt­(bzq-κN,κC10)­(C6F5)­(CH3COCH3)] (2). Treatment of 5 with dmso or direct oxidation of [Pt­(bzq-κN,κC10)­(C6F5)­(tht)] (3) provides mononuclear [Pt­(bzq-κN,κC10)­(C6F5)­X2(L)] (L = dmso (7a–c), tht (8a–c)) as a mixture of cis and trans isomers.