Nickel and Palladium Complexes of a PP(O)P Pincer Ligand Based upon a peri -Substituted Acenaphthyl Scaffold and a Secondary Phosphine Oxide.

A PP(O)P pincer ligand based upon a peri -substituted acenaphthyl (Ace) scaffold and a secondary phosphine oxide, (5-Ph 2 P-Ace-6-) 2 P(O)H, was prepared and fully characterized including a neutron diffraction study. The reaction with [Ni(H 2 O) 6 ]Cl 2 and PdCl 2 produced ionic metal(II) complexes [κ 3 - P , P' , P'' ((5-Ph 2 P-Ace-6-) 2 P(OH))MCl]Cl, which upon addition of Et 3 N gave rise to zwitterionic metal(II) complexes κ 3 - P , P' , P'' ((5-Ph 2 P-Ace-6-) 2 P(O))MCl (M = Ni, Pd). The reaction with Ni(COD) 2 (COD = cyclooctadiene) provided the η 3 -cyclooctenyl Ni(II) complex κ 3 - P , P' , P'' ((5-Ph 2 P-Ace-6-) 2 P(O))Ni(η 3 -C 8 H 13 ). A detailed complementary bonding analysis of the P-H, P-O, and P-M interactions was carried out (M = Ni, Pd).