Electron nuclear double resonance of triplet diphenylmethylene in P21 benzophenone: Conformation and spin distribution

The angular variation of the ENDOR transition frequencies has been studied for all the protons of the ground state triplet molecule molecule diphenylmethylene in a single crystal of benzophenone in its P21 phase at T?2 °K. The hyperfine coupling tensor for each proton has been determined from the experimental data. The molecular confirmation and spin densities are given which best reproduce the anisotropic components of these tensors under the constraint of a distributed point dipole model. There is a slight but readily discerned imbalance in the spin distribution between the two rings, and one phenyl ring is shown to be rotated out of the plane of the divalent carbon hybridization more than the other phenyl ring.