Microwave Spectra of Nitrogen-Containing Molecules. IV. Conformation, Dipole Moment, and Quadrupole Coupling Constants of Cyclopropylamine

The microwave spectra of three isotopic species of cyclopropylamine have been investigated. The A, B, and C rotational constants in megahertz for C3H5NH2 are, respectively, 16269.95, 6723.00, and 5795.33; for C3H5NHD they are 15957.12, 6382.01, and 5504.06; and for C3H5ND2 they are 15592.62, 6091.39, and 5246.56. Quadrupole coupling constants have been measured and have the values χaa = 2.288, χbb = 1.841, and χcc = −4.129 MHz for the normal isotopic species. The dipole-moment components are found to be μa = 0.43 D and μc = 1.11 D which lead to a total moment of 1.19 D. The molecular structure of cyclopropylamine has been discussed, and in addition to other structural parameters, we have found C–C = 1.520, C–N = 1.428, and amino H···H = 1.631 Å.