Acknowledgment.. We thank the National Science Foundation and the Du Pont Co. for financial support and Mr. David Ting for technical assistance. ... 12, 5908-41-8; 13,61634-71-7; diphenyl diselenide, 1666-13-3; benzyl chloride, 100-44-7; benzyl phenyl selenide, 18255-05-5; MesSiCl, 75-77-4; methyl iodide, 74-88-4; bis(3-trifluoromethy1)phenyl di- selenide, 53973-75-4; benzyl m-trifluoromethylphenyl selenide, 61634-72-8; chlorodimethylsilane, ...