Properties of trifluoromethylgermanes. Adduct formation and substitution reactions of (CF3)nGeX4−n (n = 2–4) with NH3
摘要:
Crystalline adducts of compositions (CF3)4Ge.nRNH2 (R = H: n = 2, 3; R = CH3: n = 1, 2) with dissociation vapour pressures at 22-degrees-C of 70 (R = H) and 75 mbar (R = CH3) have been isolated. From their Raman spectra both NH3 adducts are judged to have a cis-configurated octahedral coordination at the germanium atom. Reaction of (CF3)3GeI with NH3 yielded the digermazane [(CF3)3Ge]2NH whereas the cyclic trimers [(CF3)2GeNR]3 (R = H, CH3) were obtained from (CF3)2GeI2 and RNH2. IR spectra show that NH3 and [(CF3)3Ge]2NH undergo equilibration to give (CF3)3GeNH2 in the gas phase, with simultaneous formation of a solid phase with the composition (CF3)3GeNH2.2NH3. Addition of trimethyl- or triethyl-amine to [(CF3)3Ge]2NH yields solid 1:1 adducts. The vibration spectra of [(CF3)3Ge]2NH, (CF3)3GeNH2 and of the NH3 adducts of (CF3)4Ge and of their deuterated analogues have been analyzed. A Ge-N-Ge bond angle of 130-degrees was deduced for [(CF3)3Ge]2NH from model force constant calculations.