Electronic and Structural Variations of a Nickel(0) N-Heterocyclic Phosphenium Complex in Comparison to Group 10 Analogues

Leah K Oliemuller; Curtis E Moore; Christine M Thomas

doi:10.1021/acs.inorgchem.2c03302

Electronic and Structural Variations of a Nickel(0) N-Heterocyclic Phosphenium Complex in Comparison to Group 10 Analogues

Inorg Chem. 2022 Dec 5;61(48):19440-19451. doi: 10.1021/acs.inorgchem.2c03302. Epub 2022 Nov 22.

Authors

Leah K Oliemuller¹, Curtis E Moore¹, Christine M Thomas¹

Affiliation

¹ Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States.

PMID: 36414021
DOI: 10.1021/acs.inorgchem.2c03302

Abstract

The bonding interactions and electronic structure of a diphosphine pincer ligand featuring an N-heterocyclic phosphenium/phosphido (NHP^±) central moiety with nickel are explored. Treating Ni(COD)₂ with the pincer ligand [PPP]Cl in the presence of a two-electron phosphine donor ligand PMe₃ generates chlorophosphine complex (PP^ClP)Ni(PMe₃) (2a). The cationic Ni complex [(PPP)Ni(PMe₃)][BPh₄] (3a) can be prepared by subsequent halide abstraction from 2a with NaBPh₄. The assignment of 3a as a Ni⁰/NHP⁺ complex, based on analysis of structural parameters and computational investigations, lies in contrast to its previously reported group 10 M^II/NHP^- (M = Pd, Pt) analogues. The activation of O-H bonds across the Ni-P^NHP bond is demonstrated by the addition of isopropanol to afford the metal hydride species [(PP^OiPrP)Ni(PMe₃)(H)][BPh₄] (4). Notably, the installation of a P-H bond in the NHP unit by treatment of 2a with LiAlH₄ yields (PP^HP)Ni(PMe₃) (6). The ambiphilic nature of the P-H bond was demonstrated through reactivity studies of P-H bond cleavage in comparison to a Pd analogue (PP^HP)Pd(PPh₃) (8).