Experimental and theoretical investigations of the molecular structure and the spin state of the carboranyl nitronyl nitroxide radical

A carborane derivative containing two nitronyl nitroxide moieties, OCB-BNN was successfully synthesized and characterized. On the ESR study in the benzene solution, nonet lines of the hyperfine structure owing to the equivalent four nitrogen nuclei were observed. An X-ray crystallographic analysis revealed that the crystal lattice has a one-dimensional cavity. The spin distribution and the singlet-triplet energy gap of OCB-BNN were evaluated by the DFT calculation (UB3LYP-6-31G*). The synthesis, structure, ESR measurement and DFT calculation will be discussed.