Synthesis of Os Hydride Complexes Supported by the Diarylamido/Bis(phosphine) PNP Ligand and Attempts at Using (PNP)Ru and (PNP)Os Complexes in C-H Borylation Catalysis

Patricio Castillo; Bryan J Foley; Samuel R Lee; Billy J McCulloch; Nattamai Bhuvanesh; Oleg V Ozerov

doi:10.1021/acs.organomet.4c00388

Synthesis of Os Hydride Complexes Supported by the Diarylamido/Bis(phosphine) PNP Ligand and Attempts at Using (PNP)Ru and (PNP)Os Complexes in C-H Borylation Catalysis

Organometallics. 2024 Nov 12;43(22):2944-2950. doi: 10.1021/acs.organomet.4c00388. eCollection 2024 Nov 25.

Authors

Patricio Castillo¹, Bryan J Foley¹, Samuel R Lee¹, Billy J McCulloch¹, Nattamai Bhuvanesh¹, Oleg V Ozerov¹

Affiliation

¹ Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States.

Abstract

This manuscript describes the synthesis of Os complexes supported by the diarylamido/bis(phosphine) PNP pincer ligand. Compound (PNP)OsH(CO) (3-Os) was prepared by analogy with the previously reported 3-Ru. However, attempts to make (PNP)OsH₃ (4-Os) analogously to 4-Ru resulted in the formation of an unexpected compound (5-Os) that is a product of addition of a BH₃ unit across the Os-N bond in 4-Os. Nonetheless, 4-Os was prepared via an alternative route. Unlike 4-Ru, 4-Os appears to be a classical trihydride. Compounds 3-Ru, 3-Os, 4-Os, 4-Ru, and 5-Os were tested as potential catalysts for (a) dehydrogenative borylation of terminal alkynes (DHBTA) and (b) dehydrogenative borylation of benzene. No catalytic C-H borylation was observed for any of them, but all of them catalyzed unselective hydroboration of 4-MeC₆H₄CCH.