Experimental and computational modeling of biphenyl twisting in a solid-to-solid carbene reaction

Computational modeling of a carbene 1,2-H shift in the solid-to-solid reaction of 1-(4-biphenyl)-2-phenyldiazopropane to (Z)-1-(4-biphenyl)-2-phenylpropene predicts that the planar biphenyl substituent of molecules witnessing the reaction will twist to relieve some of the steric strain accumulated in the crystal lattice. Changes in Raman spectra followed as a function of reaction progress confirmed that prediction and suggest a solid state reaction that proceeds through continuous solid solution. (C) 1998 Elsevier Science Ltd. Ail rights reserved.