Diverse Reactivity of bis(Silylene) and bis(Germylene) [LE-EL (E=Si and Ge: L=PhC(NtBu)₂)] in the Oxidative Activation of C-F Bond: Si-Si Bond is Retained While the Ge-Ge Bond Is Cleaved

Herein we report the reactions of 3,4,5,6-tetrafluoroterephthalonitrile (1) with bis(silylene) and bis(germylene) LE-EL [E=Si (2) and Ge(3): L=PhC((NBu)-Bu-t)(2))]. The reaction of LSi-SiL (L=PhC((NBu)-Bu-t)(2)) (2) with two equivalents of 1 resulted in an unprecedented oxidative addition of a C-F bond of 1 leading to disilicon(III) fluoride {L(4-C8F3N)FSi-SiF(4-C8F3N)L}(4), wherein the Si-Si single bond was retained. In contrast, the reaction of LGe-GeL (L=PhC((NBu)-Bu-t)(2)) (3) with one equivalent of 1 resulted in the oxidative cleavage of Ge-Ge bond leading to L(4-C8F3N2)Ge (5) and LGeF (6). All three compounds (4-6) were characterized by NMR spectroscopy, EI-MS spectrometry, and elemental analysis. X-ray single-crystal structure determination of compound 4 unequivocally established that the Si-III-Si-III bond remains uncleaved.