Thorium Metallocene Cation Chemistry: Synthesis and Characterization of the Bent [(C5Me5)2Th(C6H5)(THF)][BPh4] and the Parallel Ring [(C5Me5)2Th(NCR)5][BPh4]2 (R = Me, Ph) Complexes

Abstract

Attempts to synthesize the base-free dication [(C5Me5)2Th]2+ by reaction of the bis(allyl) complex (C5Me5)2Th(C3H5)2 with 2 equiv of [Et3NH][BPh4] in benzene yielded a cationic phenyl complex that, in the presence of THF, crystallized from toluene as [(C5Me5)2Th(C6H5)(THF)][BPh4]. The reaction of the dimethyl complex (C5Me5)2ThMe2 with [Et3NH][BPh4] in toluene in the presence of nitriles RCN generates cations of the formula [(C5Me5)2Th(NCR)5][BPh4]2 (R = Me, Ph) in 40–55% crystalline yield. The molecular structures reveal the first examples of thorium cyclopentadienyl metallocene complexes with parallel rings.