E. Sato, M. Ohara, Y. Yamaoka, O. Ohashi, N. Kuze, T. Sakaizumi
JOURNAL OF MOLECULAR SPECTROSCOPY 244(1) 79-86 2007年7月
The microwave spectra of cyclohexanone oxime and d(1) (=NOD) and d(4)(2,2,6,6-d(4)) derivatives were observed in the frequency range from 8 to 40 GHz in the ground and excited vibrational states. The rotational constants were determined to be A = 3799.844(48), B = 1513.7912(23), and C = 1189.6118(29) MHz for normal species, A = 3791.835(88), B = 1461.0324(47), and C = 1157.5653(53) MHz for d(1) species, and A = 3364.141(49), B = 1487.9551(34), and C = 1154.0965(44) MHz for d(4) species in the ground vibrational state. The planar moments, P-bb (P-bb =(I-c + I-a - I-b)/(2)) of normal, d(1), and d(4) species were determined to be 111.9885(26), 111.9817(46), and 124.2394(49) u angstrom(2), respectively. The almost same values of P-bb of normal and d(1) species suggest that the hydroxyl hydrogen atom is very close to the a-c plane. From the r(s) coordinates of the hydroxyl hydrogen atom, the OH bond was found to be at the trans position with respect to the C=N double bond. The conformation of cyclohexanone oxime was determined to be chair form by comparing the observed and calculated rotational constants, Delta I, and planar moments, and taking account of the calculated the relative energy difference, Delta E. The structural parameters, the three bond lengths, three bond angles, and three dihedral angles, were adjusted to the nine rotational constants observed. The bond angle of angle C2C1N is much wider than that of angle C6C1N by about 10 degrees. The dihedral angles of angle C1C2C3C4, angle C2C3C4C5, and angle C3C4C5C6 were determined to be 53.3(5), -57.2(5), and 57.2(5)degrees. Two vibrational modes were assigned to the ring-bending and ring-twisting ones, which are almost harmonic up to v = 3. (C) 2007 Elsevier Inc. All rights reserved.