| Abstrakt: |
The structure of the CH2ClFHCCH dimer has been determined using both chirped-pulse and resonant cavity Fourier-transform microwave spectroscopy. The complex has Cssymmetry and contains both a double C–Hπ interaction, in which one π-bond acts as acceptor to two hydrogen atoms from the CH2ClF donor, and a weak C–HCl interaction, with acetylene as the donor. Analysis of the rotational spectra of four isotopologues (CH235ClFH12C12CH, CH237ClFH12C12CH, CH235ClFH13C13CH, and CH237ClF–H13C13CH) has led to a structure with C–Hπ distances of 3.236(6) Å and a C–HCl distance of 3.207(22) Å, in good agreement with ab initiocalculations at the MP2/6-311++G(2d,2p) level. Both weak contacts are longer than those observed in similar complexes containing a single C–Hπ interaction that lies in the Csplane; however, this appears to be the first double C–Hπ contact to be studied by microwave spectroscopy, so there is little data for direct comparison. The rotational and chlorine nuclear quadrupole coupling constants for the most abundant isotopologue are: A= 5262.899(14) MHz, B= 1546.8074(10) MHz, C= 1205.4349(7) MHz, χaa= 28.497(5) MHz, χbb= −65.618(13) MHz, and χcc= 37.121(8) MHz. [ABSTRACT FROM AUTHOR] |
