A Distinct Tetradentate N2O2-type Ligand: (o-Carboranyl)bis(2-hydroxymethyl)pyridine

A new chiral racemic ligand (o-carboranyl)bis(2-hydroxymethyl)pyridine oCB(hmpH)2, that is composed of a central o-carborane unit where two arms radiate out of the cluster carbons each one containing a 2-pyridylmethylalcohol chelating arms, provides two potentially bidentate {NO} or one tetradentate {N2O2} binding pockets. An unprecedented octahedral CoII complex [CoCl2(anti-oCB(hmpH)2] was obtained under aerobic conditions and characterized by X-ray crystallography as well as IR and NMR spectroscopy. anti-oCB(hmpH)2 acts as a tetradentate N2O2-ligand affording the complex as a racemic mixture of cis- -[CoCl2(RRanti-oCB(hmpH)2)] and -[CoCl2(SSanti-oCB(hmpH)2)]. The new ligand oCB(hmpH)2 appears to be suitable for producing a variety of new chiral-at-metal complexes.