Microwave spectrum, structure, and quadrupole coupling for the ethylene–hydrogen cyanide complex

Abstract

Microwave spectra for the complexes ethylene–HCN and ethylene–DCN were observed with the pulsed beam, Fourier transform spectrometer. The complexes are ‘‘T’’ shaped with the HCN hydrogen atom adjacent to the C–C double bond of ethylene. The HCN molecule lies on a line perpendicular to the plane of ethylene and passing through the ethylene center of mass. The HCN carbon atom is 3.702(10) Å above the ethylene plane. The nitrogen quadrupole coupling strength is eQq_aa(N)=−4.363(2) MHz for ethylene–HCN and eQq_aa(N)=−4.396(3) MHz for ethylene–DCN. The deuterium quadrupole coupling strength is eQq_aa(D)=0.178(7) MHz for ethylene–DCN. The anisotropy in the nitrogen quadrupole coupling eQ(q_bb−q_cc)(N) is 0.013(3) MHz for ethylene–HCN and 0.047(12) MHz for ethylene–DCN. The rotational constants are Centrifugal distortion constants D_J and D_JK were obtained.