Flexible Coordination of SacNac Ligands in Iridium Complexes and their Application to Catalytic Hydroboration

Herein, we report the synthesis and characterization of a small family of Ir(I) and Ir(III) complexes supported by β‐thioketoiminates (SacNac) ligands. All complexes were fully characterized by IR, 1D and 2D NMR, and Elemental Analysis (e.a.) experiments. X‐ray diffraction studies were carried out to corroborate the structure of compounds [Ir(cod)(SacNac)] (1) (cod=1,5‐cyclooctadiene), [Ir(dmb)(SacNac)] (2) (dmb=2,3‐dimethyl‐1,3‐butadiene) and [IrCp*(SacNac‐H)(Cl)2] (8) (Cp*=pentamethyl‐cyclopentadienyl). Complexes 1 and 2 are Ir(I) species and have square‐planar geometry in solid state, with bond angles and distances that suggest semi‐aromaticity in the six‐membered ring. To the best of our knowledge, we report the first mono‐coordination mode of a SacNac ligand via sulfur atom in complex 8. Also, we report the first application of iridium‐SacNac complexes as catalytic precursors in hydroboration reactions, where Ir(III) species give the best results. Flexible coordination of SacNac ligands in iridium complexes and their application to catalytic hydroboration of styrene is reported. Particularly, oxygen and sulphur atoms have a deshielding effect on the olefin‐protons for all complexes. In contrast, a plausible π‐interaction between the aromatic ring and the cod protons led to shielded chemical shift effect, which is attributed to the ring anisotropy phenomenon.