Static and Dynamic Single-Crystal X-ray Diffraction Studies of Some Solid-State Photodimerization Reactions

Article abstract of DOI:10.1021/j150624a022

A class of diffusionless photochemical reactions involving (2+2) photodimerization in the solid state is described.The archetypal molecule, 2-benzyl-5-benzylidenecyclopentanone (BBCP), and its p-bromo derivative (BpBrBCP) crystallize into space groups and unit cells which permit single-crystal -> single crystal transformation to occur.Detailed crystallographic studies of these materials at various stages of solid-state conversion at room temperature are described.In particular, for the case of BBCP, the "formation" of the cyclobutane ring between the two monomers in an incipient dimer can be directly identified by using dynamic four-circle diffractometry.Full structural and related details are presented.