Microwave structure measurements on the cyclopropanendash;HCN complex

摘要

Microwave rotational transitions for the cyclopropanehyphen;HCN complex were observed using the Flygarendash;Balle pulsed beam Fourier transform spectrometer. The 111rarr;212, 101rarr;202, 110rarr;211, 212rarr;313, 202rarr;303, 211rarr;312, 313rarr;414, 303rarr;404, 312rarr;413, 414rarr;515, 404rarr;505, and 413rarr;514transitions were observed. The rotational constants obtained areA=20thinsp;243plusmn;1344 MHz,B=1384.209plusmn;0.001 MHz, andC=1327.901plusmn;0.001 MHz. The distortion constants areDJ=1.53plusmn;0.03 kHz andDJK=50.9plusmn;1.1 kHz. The nitrogen quadrupole coupling strength iseQqaa=minus;4.38plusmn;0.01 MHz witheQqbbminus;eQqcc= 0.002plusmn;0.003 MHz. The cyclopropane carbon atoms and HCN lie in a plane. The most reasonable bond distance is obtained with the HCN hydrogen atom bonding to the midpoint between two of the cyclopropane carbon atoms. The separation of the centers of mass of HCN and cyclopropane isRcm= 4.472plusmn;0.002 Aring;. The HCN carbon atom isRCCndash;C=3.476plusmn;0.002 Aring; from the cyclopropane carbonndash;carbon bond. The stretching force constant isks=0.062 mdyn/Aring; and the approximate bonding energy is 860 cmminus;1.