Macrocyclic Aryl–Nickel(II) Complexes: Synthesis, Structure, and Reactivity Studies YangChi WuWen-Di ZhaoLiang WangMei-Xiang 2015 The synthesis, characterization, and reactivity of the monoaryl–Ni­(II) compound <b>2</b> and the diaryl–Ni­(II) compound <b>4</b> formed through the direct electrophilic metalation of two macrocyclic azacalix­[<i>m</i>]­arene­[<i>n</i>]­pyridine ligands are described. Compound <b>4</b> was much more stable in protic solvents and acids than the monoaryl–Ni­(II) compound <b>2</b>. Moreover, <b>2</b> can react with a variety of nucleophiles, resulting in the formation of C–C, C–O, C–Br, and C–N bonds. In contrast, compound <b>4</b> exhibited very inert reactivity upon reaction with a large numberof nucleophiles. Interestingly, compound <b>2</b> was also capable of reacting with several less bulky alkyl halides to form new C–C bonds, while the same procedure is inapplicable to <b>4</b>. The study reported in this work provides a thorough investigation on the reactivity of aryl–Ni­(II) species that should facilitate comprehension of the detailed mechanism of nickel-catalyzed C–H functionalization.