Terminal Phosphanido Rhodium Complexes Mediating Catalytic PP and PC Bond Formation

Abstract

Complexes with terminal phosphanido (MÀPR 2 ) functionalities are believed to be crucial intermediates in new catalytic processes involving the formation of PÀP and PÀC bonds. We showcase here the isolation and characterization of mononuclear phosphanide rhodium complexes ([RhTp(H)-(PR 2 )L]) that result from the oxidative addition of secondary phosphanes, a reaction that was also explored computationally. These compounds are active catalysts for the dehydrocoupling of PHPh 2 to Ph 2 PÀPPh 2 . The hydrophosphination of dimethyl maleate and the unactivated olefin ethylene is also reported. Reliable evidence for the prominent role of mononuclear phosphanido rhodium species in these reactions is also provided.

Rhodium(i) complexes derived from tris(isopropyl)-azaphosphatrane—controlling the metal–ligand interplay

“…0.030–0.207 Å) than other representative Rh–phosphido bonds reported in the literature. 26 The P1 atom nearly lies in the plane of Rh1–N2–N8. The sum of three angles around the phosphorus atom (Rh1–P1–N2, Rh1–P1–N8, and N2–P1–N8) equals 350.26°, expressing a pseudo-trigonal bipyramidal geometry around the phosphorus atom, which deviates from the more common tetrahedral geometries of phosphines.…”

Synthesis of a carborane-substituted bis(phosphanido) cobaltate(i), ligand substitution, and unusual P4fragmentation

“…Even when acting as simple 'spectator' ligands, their properties as very strong σ and π donors can dramatically influence the electronic structure and hence the reactivity at the metal. 1 In addition, the presence of sterically and electronically accessible lone pairs of electrons leads to highly reactive metal-phosphorus bonds, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] allowing for additional, 'non-innocent' reactivity toward substrates including Brønsted acids, 4,[10][11][12]17 electrophiles, 4,7,10,17 and unsaturated π systems. 19 Moreover, terminal phosphanido complexes can serve as metalloligands for heterobimetallic complexes.…”

“…2,3 Terminal phosphanido complexes have also been utilised in catalytic hydrophosphination and dehydrocoupling reactions. 6,8,11,13,16 While monodentate phosphanido ligands have been quite extensively explored, complexes with chelating, terminal bis(phosphanido) ligands are comparably understudied. In addition to the improved stability and rigidity that are inherent to the use of chelates, such ligands are expected to lead to further enhancements in reactivity due to the presence of two non-innocent nucleophilic sites in close proximity, as well as the cumulative electronic effects of the two donor moieties on the transition metal centre.…”

9-BBN and chloride catalyzed reduction of chlorophosphines to phosphines and diphosphines

“…12 In the 1990s, we established catalytic routes to the generation of diphosphines and polyphosphines using a Zr based catalyst. [13][14][15] Subsequent studies by Waterman 16 Webster, 17 Brookhart 18 and Tejel 19 established the utility of new Zr, Fe and Rh catalysts (Scheme 1) for similar dehydrocoupling reactions. 20 Wright and coworkers established the first main group catalyst for dehydrocoupling of phosphines, using Cp* 2 SnCl 2 .…”