REBECCA A. PEEBLES, SEAN A. PEEBLES, CORI L. CHRISTENHOLZ, ANTHONY A. ERNST AND YASSER J. DHAHIR, Department of Chemistry, Eastern Illinois University, 600 Lincoln Ave., Charleston, IL 61920.
The spectra of the CH2F2 propyne and CH2ClF propyne complexes have been studied by chirped-pulse and resonant cavity Fourier-transform microwave spectroscopy and by ab initio calculations at the MP2/6-311++G(2d,2p) level. Both complexes contain C--H contacts, with the halogen atoms angled towards the methyl group end of the propyne. While CH2F2 propyne has Cs symmetry, CH2ClF propyne has C1 symmetry, with the fluorine and chlorine atoms straddling the propyne.
Investigation of four single 13C and the DCCCH3 isotopologues in CH2F2 propyne has allowed a detailed structural determination, while only the 35Cl and 37Cl isotopologues have so far been assigned for CH2ClF propyne. Experimental data will be compared with ab initio results and with the analogous acetylene complexes, both of which have Cs symmetry structures, with double C--H interactions.