Preparation and reactivity of macrocyclic rhodium(III) alkyl complexes

•Preparation of a new series of organorhodium complexes.•Spectroscopic and structural characterization.•Alkylrhodium complexes are thermally robust.•UV irradiation leads to ready cleavage of rhodium–carbon bond.

Macrocyclic rhodium(II) complexes LRh(H2O)2+ (L = L1 = cyclam and L2 = meso-Me6-cyclam) react with alkyl hydroperoxides RC(CH3)2OOH to generate the corresponding rhodium(III) alkyls L(H2O)RhR2+ (R = CH3, C2H5, PhCH2). Methyl and benzyl complexes can also be prepared by bimolecular group transfer from alkyl cobaloximes (dmgH)2(H2O)CoR and (dmgBF2)2(H2O)CoR (R = CH3, PhCH2) to LRh(H2O)2+. The new complexes were characterized by solution NMR and by crystal structure analysis. They exhibit great stability in aqueous solution at room temperature, but undergo efficient Rh–C bond cleavage upon photolysis.

Graphical abstractMacrocyclic mononuclear rhodium(II) complexes react with alkyl hydroperoxides to generate thermally stable alkyl rhodium complexes that undergo efficient rhodium–carbon bond cleavage upon photolysis.Figure optionsDownload full-size imageDownload as PowerPoint slide