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Abstract The coordination sphere of the reported (1,3-bis(3-butylimidazol-1-yl-2-idene)-2-phenylene)( tert -butylimido) CCC-NHC Ta (V) bis(imido) pincer complex 2 (Helgert et al., 2016, doi: 10.1021/acs.organomet.6b00216 ) has been observed to spontaneously rearrange… Click to show full abstract
Abstract The coordination sphere of the reported (1,3-bis(3-butylimidazol-1-yl-2-idene)-2-phenylene)( tert -butylimido) CCC-NHC Ta (V) bis(imido) pincer complex 2 (Helgert et al., 2016, doi: 10.1021/acs.organomet.6b00216 ) has been observed to spontaneously rearrange to yield X-ray quality crystals of a CCC-NHDC/NHC pincer Ta (V) bis(imido) complex ( 3 ). Preliminary computations were consistent with a step-wise mechanism for the formation of the N -heterocyclic dicarbene pincer complex. Over time the CCC-NHC Ta (V) bis(imido) pincer complex 2 reacted with adventitious protons sources to form CCC-NHC Ta(V)( tert -butylamido)( tert -butylimido)iodo complex ( 4 ). The reaction of bis(imido) 2 with excess lithium tert -butylamide at elevated temperatures, in an effort to find a direct synthesis of 3 , yielded methylidyne species 5 .