Formation of Nickel(II) Cyanomethyl Complex Bearing Tridentate 1,2,3-Triazolylidene

A mesoionic carbene stabilized nickel(ii) hydroxide complex: a facile precursor for C–H activation chemistry

“…This is unexpected, as previously reported nickel-hydoxide complex N was found to deprotonate MeCN at the CH 3 -group forming the corresponding cyanomethyl complex. 28 Furthermore, the hydroxide complexes C and M were both studied towards their catalytic potential to catalyse the hydration of nitriles to amines 21,25 and M also stoichiometrically reacts with MeCN to form the corresponding acetamide complex. 25 Thus, the cleavage of the C–C bond in MeCN was quite unexpected but is not unprecedented as was shown by Zhang and co-workers, who reported the in situ cleavage of MeCN during the synthesis of nickel( ii )-NHC complexes from imidazolium salts, nickel acetate and NaH/KO t Bu mixtures.…”

“…27 In addition, Matsubara and co-workers reported the bulky triazolylidene complex N , which is capable to deprotonate acetonitrile at the CH 3 -group to stoichiometrically form a cyanomethyl ligand. 28 Notably, all these examples focus on the use of nickel( ii ) and yet only one nickel( iii ) hydroxide complex I has been isolated by Shanmugam et al 29…”

“…27 In addition, Matsubara and co-workers reported the bulky triazolylidene complex N, which is capable to deprotonate acetonitrile at the CH 3 -group to stoichiometrically form a cyanomethyl ligand. 28 Notably, all these examples focus on the use of nickel(II) and yet only one nickel(III) hydroxide complex I has been isolated by Shanmugam et al 29 We have recently reported the synthesis of an N-fused tridentate carbazole-MIC ligand with intriguing properties in photochemistry 30 and the stabilisation of high-valent metal ions. 31 Furthermore, its nickel(II) acetate complex O (Scheme 1), 32 was found to be a versatile catalyst for the cyclisation of carbon dioxide and epoxide, while at the same moment being a bad catalyst for the corresponding polymerisation reaction.…”