Hydrogen-Atom Noninnocence of a Tridentate [SNS] Pincer Ligand
By Rosenkoetter, Kyle E.; Wojnar, Michael K.; Charette, Bronte J.; Ziller, Joseph W.; Heyduk, Alan F.
Published in Inorganic Chemistry
2018
Abstract
Double deprotonation of bis(2-mercapto-4-methylphenyl)amine ([SNS]H3) followed by addition to NiCl2(PR3)2 in air-free conditions afforded [SN(H)S]Ni(PR3) (1a, R = Cy; 1b, R = Ph) complexes, characterized as diamagnetic, square-planar nickel(II) complexes. When the same reaction was conducted with 3 equiv of KH, the diamagnetic anions K[SNS]Ni(PR3) were obtained (K[2a], R = Cy; K[2b], R = Ph). In the presence of air, the reaction proceeds with a concomitant one-electron oxidation. When R = Cy, a square-planar, S = 1/2 complex, [SNS]Ni(PCy3) (3a), was isolated. When R = Ph, the bimetallic complex [SNS]Ni(PPh3)2 (3b2) was obtained. This bimetallic species is diamagnetic; however, in solution it dissociates to give S = 1/2 monomers analogous to 3a. Complexes 1