Flash Communication: Boron K-edge XAS and TDDFT Studies of Covalent Metal–Ligand Bonding in Ni(C2B9H11)2

Abstract

Ligand K-edge X-ray absorption spectroscopy (XAS), a technique that can measure variations in covalent metal–ligand bonding, has rarely been used to assess covalency in complexes containing metal–boron bonds. Here we describe ligand K-edge XAS and TDDFT studies of the Ni dicarbollide complex Ni(C2B9H11)2(1) and the Ni-free salt (HNMe3)(C2B9H12) (L1). The XAS spectrum for 1 reveals a pre-edge feature indicative of covalent Ni–B bonding, which is corroborated by time-dependent density functional theory (TDDFT) calculations and comparative analysis to L1 and inner-shell electron energy loss spectroscopy (ISEELS) collected on the same Ni complex.