P–P Coupling with and without Terminal Metal–Phosphorus Intermediates

Journal Article · 27 January 2025 · Journal of the American Chemical Society

DOI: https://doi.org/10.1021/jacs.4c16833 · OSTI ID:2507266

Thompson, Richard R.  ^[1]; Figgins, Matthew T. ^[2]; Wannipurage, Duleeka C. ^[2]; Renteria-Gomez, Angel  ^[2]; Gogoi, Achyut Ranjan  ^[2]; Telser, Joshua  ^[3]; Tierney, David L. ^[4]; Neben, Marc C. ^[5]; Demeshko, Serhiy ^[5]; Gutierrez, Osvaldo  ^[2]; Powers, David C.  ^[2]

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1. Texas A&M University, College Station, TX (United States); University of Idaho, Moscow, ID (United States)
2. Texas A&M University, College Station, TX (United States)
3. Roosevelt University, Chicago, IL (United States)
4. Miami University, Oxford, OH (United States)
5. Georg-August-Universität, Göttingen (Germany)

Terminal metal–phosphorus (M–P) complexes are of significant contemporary interest as potential platforms for P-atom transfer (PAT) chemistry. Decarbonylation of metal–phosphaethynolate (M–PCO) complexes has emerged as a general synthetic approach to terminal M–P complexes. M–P complexes that are stabilized by strong M–P multiple bonds are kinetically persistent and isolable. In the absence of strong M–P stabilization, the formation of diphosphorus-bridged complexes (i.e., M–P–P–M species) is often interpreted as evidence for the intermediacy of reactive, unobserved M–P species. Here, we demonstrate that while diphosphorus complexes can arise from reactive M–P species, P–P coupling can also proceed directly from M–PCO species without the intermediacy of M–P complexes. Photochemical decarbonylations of a pincer-supported Ni (II)–PCO complex at 77 K afford a spectroscopically observed terminal Ni–P complex, which is best described as a triplet, Ni(II)-metallophosphinidene with two unpaired electrons localized on the atomic phosphorus ligand. Thermal annealing of this transient Ni–P complex results in rapid dimerization to afford the corresponding P₂^2–-bridged dinickel complex. Unexpectedly, the same P₂^2–-bridged dinickel complex can also be accessed via a thermally promoted process in the absence of light. The analysis of reaction kinetics, isotope-labeling studies, and computational results indicate that the thermal P–P coupling process proceeds via a noncanonical mechanism that avoids terminal M–P intermediates. Together, these results represent the first observation of P–P coupling from characterized terminal M–P species and demonstrate that terminal M–P intermediates are not required to obtain P–P coupling products. These observations provide critical mechanistic understanding of the activation modes relevant to P-atom transfer.

• Research Organization: Texas A&M University, College Station, TX (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-06CH11357; SC0024121
• OSTI ID: 2507266
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 6 Vol. 147; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Dimerization
Ligands
Metals
Phosphorus
Photodissociation