Polar trifluoromethylation reactions: syntheses of trifluoromethyl gallium, indium, and thallium compounds. The mechanism of polar trifluoromethyl group transfer

Article abstract of DOI:10.1016/0022-328X(91)83135-Q

The reactions of Cd(CF3)2 complexes with GaCl3, InCl3, and TlX3 (X: Cl, OCOCH3, OCOCF3) in aprotic basic solvents have given the compounds Ga(CF3)3<*>dmf, Ga(CF3)2Cl<*>dmf, 2, In(CF3)3<*>2CH3CN, In(CF3)2Cl<*>dmf, and Tl(CF3)3<*>2dmf, which have been characterized by NMR spectroscopy, mass spectrometry, vibrational spectroscopy, and elemental analysis.All trifluoromethylmetal halides formed as intermediates were detected by 19F NMR spectroscopy.The dependence of the chemical shifts and the coupling constants ²J(203/205Tl-19F) on the number ofCF3-groups bound to the central atom provides unambiguous evidence for the formular of trifluoromethyl gallates and thallates and the existence of the ^--anion has been confirmed by 71 Ga NMR spectroscopy.A mechanism for successful polar trifluoromethyl group transfer is discussed on the basis of Pearson's HSAB concept and the results of conductivity measurements.