Photochemical transformations of small ring carbonyl compounds

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2928 A three-dimensional Patterson synthesis was computed from the observed data.27 The positions of the two independent bromine atoms were obtained from this synthesis. The remaining non-

hydrogen atoms were found by successive structure factor calculations and electron density syntheses. The positions were refined by full matrix least-squares techniques with anisotropic thermal parameters for all atoms to a conventional discrepancy index [R = Z/lF,/ - lFo11/21Foi] of 0.089 and a weighted R factor [wR = [Zw[lFol - IFcl]2/;SwlFo1z]1/2] of 0.119.28~29The scattering factors were those of Hanson, et al.ao A final electron density difference map showed no peaks greater

(27) J. Rodgers and R. A. Jacobson, “ALF: A General Fourier Program in PLl for Triclinic, Monoclinic, and Orthorhombic Space Groups,” U. S. Atomic Energy Commission Report IS-2155, Iowa State University, Ames, Iowa 50010. (28) W. R. Busing, I