1-[Ferrocenyl(hydroxy)methyl]-1,7-dicarba-closo-dodecaborane: Synthesis and X-ray crystal structure

The synthesis and molecular structure of the novel 1-[ferrocenyl(hydroxy)methyl]-1,7dicarba-closo-dodecaborane (1) is described. Compound 1 was synthesized from reaction of m-carborane and ferrocene carboxaldehyde using n-butyllithium (n-BuLi) or tetrabutylammonium fluoride (TBAF) in THF in 45% and 36% yield, respectively. Compound 1 consists of a ferrocene molecule tethered to m-carborane through a methylhydroxy bridge. The crystal structure of 1 was determined by single crystal X-ray diffraction analysis. Crystal data: 1 [Fe(C5H5)(C5H4-CH2O-1,7-C2B10H12)], formula weight = 359.17, crystallized in orthorhombic system, space group Pna21 with a= 19.698(4) A, b= 10.709(2) A, c= 8.520(2) A, and V= 1797.3(7) A3 and Z= 4. Refined to R1 = 0.043 for 4124 observed reflections with I/σ>2σ (I). The compound was crystallized as racemic twins in a ratio of 73(2)/27(2). The unsubstituted Cp ring was disordered and modeled as two conformations in a 53(3)/47(3) ratio. Intermolecular hydrogen bonding was observed from the hydrogen of the meta-carbon on the carborane cluster towards the hydroxyl oxygen.