Synthesis, structures and photophysical properties of (o-carboranyl)-(pyridyl)methanols

The reaction of o -carboranyllithium with two equiv. of 2-pyridinecarboxaldehyde affords 1-[(hydroxy)(pyridyl)methyl]- o -carborane ( 1 ) and 1,2-bis[(hydroxy)(pyridyl)methyl]- o -carborane ( 2 ), which have been characterized by IR and NMR spectroscopy, mass spectrometry and single-crystal X-ray diffraction. Compound 2 exhibits interesting polymorphism (monoclinic 2a and triclinic 2b ). The solid state structures of the new carboranes feature intermolecular and intramolecular hydrogen bonding interactions involving all the N and O atoms, leading to one dimensional ( 1 , 2b ) or two-dimensional ( 2a ) supramolecular structures. The photoluminescence of 1 and 2b was investigated in the solid and solution states at room temperature, respectively.