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The transition state for -hydride elimination in alkyl groups on the Pt(111) surface has been probed by studying the effects of fluorine substitution on the barriers to -hydride elimination, %@mt;sys@%%@ital@%E%@rsf@%%@sx@%H%@be@%‡%@sxx@%%@mx@%. Four different fluoroalkyl groups have been formed on the Pt(111) surface by dissociative adsorption of four fluoroalkyl iodides:  RCH2CH2−I (R CF3, CF3CH2, and CF3CF2) and (CF3)2CHCH2−I. In the absence of preadsorbed hydrogen, fluoroalkyl groups on the Pt(111) surface dehydrogenate via -hydride elimination to form unsaturated fluorocarbons and deposit hydrogen atoms onto the surface. Those hydrogen atoms then hydrogenate the remaining fluoroalkyl groups to produce fluoroalkanes that desorb rapidly from the surface. The kinetics of hydrogenation and fluoroalkane desorption are rate limited by the -hydride elimination step and thus serve as measures of the kinetics of -hydride elimination. The field effects of the fluorinated substituents increase the barriers to -hydride elimination with a reaction constant of F 19 ± 2 kJ/mol. The interpretation of this effect is that the -carbon atom in the transition state is cationic, RC···H‡, with respect to the reactant. The field effect of the fluorinated substituent energetically destabilizes the electron deficient -carbon atom in the transition state. This is consistent with observations made on the Cu(111) surface; however, the substituent effect is significantly smaller on the Pt(111) surface. On the Pt(111) surface, the transition state for -hydride elimination is less polarized with respect to the initial state alkyl group than on the Cu(111) surface. [ABSTRACT FROM AUTHOR]

The radical reaction of tributyltin hydride with o-iodo-N- methylanilides derived from α-azido acids provides an excellent access to α-(aminocarbonyl)iminyl radicals through 1,5-hydrogen transfer reaction of initially formed aryl radicals followed by β-elimination of dinitrogen from ensuing α-azido-α-(aminocarbonyl)alkyl radicals. The outcoming iminyls display a peculiar tendency to form corresponding nitriles by β-elimination of aminocarbonyl radicals. [ABSTRACT FROM AUTHOR]