Hydrogen bond vibrations of 2-aminopyridine.2-pyridone, a Watson-Crick analogue of adenine.uracil

The 2-aminopuridine.2-pyridone complex (2AP.2PY) is linked by antiparallel N-H...O=C and N-H...N hydrogen bonds, providing a model for the Watson-Crick hydrogen bond configuration of the adenine-thymine and adenine-uracil nucleobase pairs. The hydrogen bond vibrations and the three in-plane vibrations v3 (opening), v5 (shear), and v6 (stretch) were observed in the S(sub 0) and S(sub 1) states.