Activation of BH bonds in Ir(I) complexes supported by phosphine with carba-closo-dodecaborate and o-carborane ligand substituents: A DFT investigation

•We successfully explained the BH activation in Ir(I) complexes.•Two kinds of methods to obtain B-σ-iridium complexes were given.•Dispersion correction is important for calculating the energy of iridium complexes.

The structures, stability and activation of BH bonds of the twelve kinds of Ir(I) complexes supported by phosphine with o-carborane and carba-closo-dodecaborate ligand substituents, η2-C8H12Ir(I)Cl(PR2(CB11H11−)) and η2-C8H12Ir(I)Cl(PR2(C2B10H11)) (R = Me, iPr and CH(CF3)2) and η2-C8H12Ir(I)Cl(P(CH3)2X(CB11H11−)) and η2-C8H12Ir(I)Cl(P(CH3)2X(C2B10H11)) (X = CH2, NH and O) have been investigated using density functional theory (DFT) BP86 functional. Calculated results indicated that the BH bonds in η2-C8H12Ir(I)Cl(P(CH(CF3)2)2(CB11H11−)) and η2-C8H12Ir(I)Cl(PR2(C2B10H11)) (R = iPr and CH(CF3)2), as well as η2-C8H12Ir(I)Cl(P(CH3)2R(CB11H11−)) and η2-C8H12Ir(I)Cl(P(CH3)2R(C2B10H11)) (R = CH2, NH and O) are both thermodynamically and dynamically favorable to be activated, in which the oxidation addition of BH bond in η2-C8H12Ir(I)Cl(P(iPr)2(C2B10H11)) is consistent with the experimental results. In contrast, the BH bonds in η2-C8H12Ir(I)Cl(P(R)2(CB11H11−)) (R = Me and iPr) and η2-C8H12Ir(I)Cl(P(CH3)2(C2B10H11)) cannot be activated, in which η2-C8H12Ir(I)Cl(P(iPr)2(CB11H11−)) is consistent with the experimental result. The activation of BH bonds in carba-closo-dodecaborate phosphine and o-carborane phosphine of Ir(I) complexes depend up the distance between BH bond and Ir(I). Moreover, two kinds of approaches to obtain B-σ-irridium (III) complexes were given by the activation of BH bonds in Ir(I) complexes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide