Microwave spectra and structure of the amine group in 3-aminopyridine and 4-aminopyridine. Ab initio molecular orbital calculations of the structure of the amine group in the aminopyridines

Microwave spectra of the ground and first excited vibrational states of the normal and amine deuterated species of 3-aminopyridine and 4-aminopyridine have been assigned and the structure of the amine group has been determined in these two molecules. The structure of the amine group in the aminopyridines has been derived from ab initio molecular orbital calculations using single determinant molecular orbital wave functions constructed from standard minimal basis sets of contracted Gaussian orbitals. The experimental and theoretical results are found to be in broad agreement with each other.