Synthesis of Mono-, Di-, and Trinuclear Rhodium Diphosphine Complexes Containing Light-Harvesting Fluorene Backbones

Rhodium(I) Complexes with a η1-Fluorenyl-P-phosphanylphosphorane Ligand

The first example of a P-phosphanylphosphorane, Flu═PCy2-PCy2 (L2; Flu = 9-fluorenyl), has been easily prepared by P-phosphination of lithiated 9-dicyclohexylphosphinofluorene (FluPCy2, L0) with chlorodicyclohexylphosphane. L2 constitutes a new type of P(III)-P(V) organophosphorus compound, a σ3λ3-σ4λ5 species that is stable under an inert atmosphere in the solid state. The reaction of L2 with [Rh(diene)2]BR4 causes metalation of the benzylic carbon (C9) of fluorene, giving κ2-C,P complexes in which fluorene is coordinated in the η1 form. A complex with the weakly coordinating BArF anion has been isolated and fully characterized, including its crystal structure obtained by X-ray diffraction.

Lewis Acid Enables Ketone Phosphorylation to Form a C-P Bond and a C-C Bond: Synthesis of 9-Phosphoryl Fluorene Derivatives

An efficient method for the Lewis acid promotion of the synthesis 9-phosphoryl fluorenes has been reported. This method focuses on ketone phosphonylation to form a C-P bond and a C-C bond between diphenylmethanone and H-phosphinate esters, H-phosphites, and H-phosphine oxides via phospha-aldol elimination, in which a series of 9-phosphoryl fluorene derivatives were selectively obtained in moderate to excellent yields.

On-demand hydrogen production from formic acid by light-active dinuclear iridium catalysts

Light-active dinuclear iridium pentahydride complexes catalyze the decomposition of formic acid to generate H₂ by irradiation (λ =395 nm) under ambient temperature and base-free conditions. The catalyst activity is sensitive to light producing H₂ under light irradiation, but with no reaction being observed in the absence of light or when the light is switched off, thereby demonstrating the clear ON/OFF switching ability of this system. Importantly, the dinuclear structure of the catalyst is sufficiently stable to be maintained under the catalytic conditions employed herein.

Light-driven catalytic hydrogenation of carbon dioxide at low-pressure by a trinuclear iridium polyhydride complex

Under irradiation conditions, low-pressure and room-temperature hydrogenation of carbon dioxide (CO₂) has been achieved using a trinuclear iridium hexahydride complex 1.

Synthesis of di- and trinuclear iridium polyhydride complexes surrounded by light-absorbing ligands

New di- and trinuclear iridium (Ir) penta- and hexahydride complexes containing light-absorbing diphosphine ligands have been developed. The trinuclear Ir complex possessed a higher absorption coefficient (standardized per Ir) than that of the parent mononuclear Ir complex, indicating the assembly effect. The trinuclear complex showed high reactivity toward catalytic hydrogenation of diphenylacetylene under mild conditions, and the reaction was considerably accelerated under photoirradiation.

Small bite-angle 2-phosphinophosphinine ligands enable rhodium-catalysed hydroboration of carbonyls

2-Phosphinophosphinine ligands generate Rh catalysts for the hydroboration of ketones and imines in contrast to standard phosphine ligands.