Fusing 10-vertex -carborane anions with N-heterocyclic carbenes.

Discovered by Knöth in 1964, the 10-vertex -carborane anion [HCBH] is a classical bicapped square antiprism that contains an unusual pentacoordinate carbon center. Compared to its larger icosahedral cousin [HCBH], few investigations have been made into its use as a weakly coordinating anion or as a ligand substituent. Here we show that it is possible to prepare both a dianionic N-heterocyclic carbene (NHC) Li adduct as well as a trianionic C-2, C-5 dilithio species featuring two 10-vertex carborane anion substituents.

Strongly Coordinating Ligands To Form Weakly Coordinating Yet Functional Organometallic Anions.

Weakly coordinating anions (WCAs) are generally tailored to act as spectators with little or no function. Here we describe the implementation of strongly coordinating dianionic carboranyl N-heterocyclic carbenes (NHCs) to create organometallic -ate complexes of Au(I) that serve both as WCAs and functional catalysts. These organometallic WCAs can be utilized to form both heterobimetallic (Au(I)/Ag(I); Au(I)/Ir(I)) and organometallic/main group ion pairs (Au(I)/(CPh or SiEt).

Analysis of stiffness reduction in varying curvature ankle foot orthoses.

Ankle foot orthoses (AFO) are often used for patients who cannot generate a strong enough extension moment at the knee to allow functional gait. Orthotists often cut out portions of the AFO around the malleoli in order to improve comfort. There has been some question as to how this affects the stress distribution around the orthosis, the fatigue performance of the device, and the AFOs stiffness.