15min:

STEPHEN G. KUKOLICH, CHAKREE TANJAROON, Department of Chemistry, University of Arizona, Tucson, AZ 85721 ; MICHAEL C. MCCARTHY AND PATRICK THADDEUS, Harvard-Smithsonian Center for Astrophysics and Division of Applied Sciences, Harvard University, Cambridge, MA 02138.

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Benzynes have been known as reactive intermediates in organic reactions for many years, and have recently been implicated in gasoline combustion reactions and antitumor activity of enediyenes. Rotational transitions were measured for the normal isotopomer, the two unique single-D isotopomers and the ¹³C₆ isotopomer of o-benzyne(o-didehydrobenzene), using a pulsed-beam Fourier transform spectrometer with an electric discharge nozzle source, using a dilute(<1%) mixture of benzene in neon. 27 b-dipole transitions for the normal isotopomer were measured in the 7-40 GHz range to obtain
A = 6989.7303(72), B = 5706.8045(71) and C = 3140.3714(50) MHz, and five centrifugal distortion constants. The inertial defect is = 0.06935 amu Ų, consistent with a planar structure. Deuterium hyperfine structure for the D₁(closest to the C-C triple bond) and D₂ (furthest from the triple bond), was analysed to obtain deuterium quadrupole coupling strengths eQq_aa = 231(17) kHz, eQq_bb = -88(13) kHz, for D₁, and eQq_aa = 29(12), and eQq_bb = 83(12) kHz, for D₂. The C-D bond axis quadrupole coupling strengths will be compared with values for benzene.