Microwave spectra, inversion splittings and quadrupole coupling constants of NHDCl and ND2Cl

The microwave spectra of monochloroamine (NH2Cl) and its isotopic species have been observed by Cazzoli et al. [G. Cazzoli, D.G. Lister, P.G. Favero, J. Mol. Spectrosc. 42 (1972) 286-295; G. Cazzoli, D.G. Lister, J. Mol. Spectrosc. 45 (1973) 467-474]. We observed microwave spectra of four isotopic species of 14NHD35Cl, 14NHD37Cl, 14ND235Cl, and 14ND237Cl produced by the direct reaction of ammonia gas-d3 or ammonium hydroxide-d5 with N-chlorosuccinimide. The microwave spectra of NHDCl (d1-species) and ND2Cl (d2-species) were observed in the frequency range from 8.0 to 60 GHz. The inversion splitting (ΔEo) of 14NHD35Cl and 14NHD37Cl in the ground vibrational state are shown to be 11.46(15) and 11.44(15) MHz for Ka = 0 ← 1, and 10.49(15) and 10.26(15) MHz for Ka = 1 ← 2, respectively. However, the inversion splitting of the d2-species could not be observed in our spectrometer. Only small J and K-dependence of the inversion splitting of d1-species was observed. The rotational constants of 14NHD35Cl were determined to be A = 187895.44(18), B = 13353.343(15) and C = 12859.794(15) MHz for the 0+ ← 0− state, which means the transition from the lower inversion level to the upper one, and A = 187918.52(18), B = 13353.345(15) and C = 12859.798(14) MHz for the 0− ← 0+ state. The rotational and centrifugal distortion constants of 14ND235Cl were determined to be A = 141030.885(72), B = 12594.481(6) and C = 12055.356(6) MHz, and ΔJ = 18.342(23), ΔJK = 318.15(56), ΔK = 2219.3 (fixed), δJ = 0.8717(17) and δK = 157.78(61) kHz. The values of the planar moments Pbb = (Ib − Ia − Ic)/2, of 14ND235Cl and 14ND237Cl were found to be 2.68898(2) and 2.68890(2) u Å2, respectively, which are about twice as large as those of normal species (Pbb = 1.3548(6) and 1.3544(16) u Å2, respectively). It was found that the bond length of r(N-Cl) of NH2Cl was longer than that of Cl-NCO by 0.045(12) Å, and was almost the same as that of CH2N-Cl, while it was much shorter than those of Cl-NO2 and Cl-NO, by 0.092(6) and 0.227(6) Å, respectively.