Versatile Synthesis of PR2NR′2 Ligands for Molecular Electrocatalysts with Pendant Bases in the Second Coordination Sphere

Two 1,5-diaza-3,7-diphosphacyclooctane (P2N2) ligands with alkyl-substituted phosphines have been synthesized via a versatile method that allows for improved control of the phosphine substituent. The methyl- and benzyl-substituted phosphine P2N2 ligands (PMe2NPh2 and PBn2NPh2) were synthesized and characterized by 31P­{1H} NMR, 1H NMR, and elemental analysis, and their corresponding [Ni­(PR2NPh2)2]­(BF4)2 complexes were synthesized and characterized by 31P­{1H} NMR, 1H NMR, and electrochemistry. The structure of the complex [Ni­(PMe2NPh2)2]­(CF3SO3)2 was characterized by X-ray crystallography.