Fig. 1: Structure formula and single crystal structures of catalysts.
From: Direct copolymerization of ethylene with protic comonomers enabled by multinuclear Ni catalysts

a Synthesis of tetranuclear nickel complexes 2a-2c. b Single crystal structures of complexes 2a and 2c. c Literature reported nickel complexes 3, 4 and 5. d Synthesis of complex 7. e Single crystal structure of complex 7.