Measurements of microwave and NMR spectra for N-15 substituted formamidinium formate

A sample of doubly-substituted N-15 formamidinium formate was synthesized and the microwave spectrum was measured in the 5.6-14.2 GHz frequency range using a Flygare-Balle type pulsed beam Fourier transform microwave (MW) spectrometer. A total of 13 a-type rotational transitions were measured and fitted to obtain the rotational constants and centrifugal distortion constants for the N-15 substituted isotopologue. The rotational constants and centrifugal distortion constants determined have the following values: A = 5808.02(18) MHz, B = 2127.008(2) MHz, C = 1557.615(2) MHz, D-J = 0.60(11) kHz, D-JK = 4.95(71) kHz and D-K = -0.138(24) kHz. Tunneling splittings were searched for, but not observed. NMR spectra for this compound are reported including values of delta(C), delta(N), (1)J(CH), (1)J(CN) and (2)J(NH) in CD3SOCD3, CD3OD and D2O. The occurrence of NH to ND exchange in D2O allowed the fortuitous measurement of (1)J(ND). (C) 2021 Elsevier Inc. All rights reserved.