Room-temperature stable ground-state triplet carbene with perpendicular conformation as models for organic high-spin units with robust π-spin polarization

A ground-state triplet diphenylcarbene derivative, 2,2′,4,4′,6,6′-hexabromodiphenylcarbene 2 was synthesized and generated to be a model for chemically stable organic high-spin molecules. This paper describes ESR detection of 2 in the crystal of the diazo precursor 1 and the molecular and crystal structure of the diazo precursor obtained by X-ray diffraction at room temperature. The crystal is monoclinic with cell dimensions, a=9.993Å, b=13.261Å, c=12.743Å, θ=91.88°, Z=4, and the space group P2₁/n. The two phenyl rings of 2,4,6-bromo-substitution make bent perpendicular conformation with 139 degree of the bond angle at the diazo methane. Non-bonded contacts shorter than the van der Waals radii were found between the nitrogen and bromine atoms of the nearest neighboring molecules.