title: Photodecarbonylation of ketodiacids as ammonium salts: efficient formation of C-C bonds between adjacent quaternary centers in the crystalline state.
abstract: Here we report the crystallization and solid photochemistry of six quaternary ammonium salts of 2,4-di-p-carboxyphenyl-2,4-dimethyl pentanone. While salt formation resulted in solids with different melting temperatures and crystallinities, photochemical excitation in the solid state resulted in the chemoselective formation of a single product arising from the homolytic loss of CO followed by combination of the intermediate radical pair. Photochemical experiments in solution led to the product mixtures formed by combination and disproportionation of the corresponding free radical intermediates. The crystallinity of all salts was documented by DSC, 13C CP-MAS NMR, and XRPD.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 E. Charles E. Young Drive, Los Angeles, California 90095, USA.
authors.forename: Farnosh
authors.initials: F
authors.lastname: Family
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Garcia-Garibay
mesh_terms: D002248:Carbon Monoxide; D003460:Crystallization; D003653:Decarboxylation; D003998:Dicarboxylic Acids / Q000737:chemistry*; D010422:Pentanones; D055668:Photochemical Processes; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*
chemical_list: D003998:Dicarboxylic Acids; D010422:Pentanones; D000644:Quaternary Ammonium Compounds; D002248:Carbon Monoxide