Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5377359 | Chemical Physics | 2006 | 7 Pages |
Abstract
The vibrational frequencies of the N-H stretching modes of aniline after forming a strong doubly H-bonded complex with tetrahydrofuran (THF) are measured with infrared depletion spectroscopy that uses cluster-size-selective resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Two strong infrared absorption features observed at 3355 and 3488 cmâ1 are assigned to the symmetric and antisymmetric N-H stretching vibrations of the 1:2 aniline-THF complex, respectively. The red-shifts of the N-H stretching vibrations of aniline agree with the ab initio calculated (MP2/6-31G**) aniline-(THF)2 structure in which both aniline N-H bonds interact with the oxygen atom of THF through two hydrogen bonds. The calculated binding energy is found to be 29.6 kJ molâ1 after corrections for basis set superposition error (BSSE) and zero-point energy. The calculated structure revealed that the angle between the N-H bonds in the NH2 group increased to 112.5° in the aniline-(THF)2 complex from that of 109.8° in the aniline. The electronic 0-0 band origin for the S1 â S0 transition is observed at 32,900 cmâ1 in the aniline-(THF)2 complex, giving a red-shift of 1129 cmâ1 from that of the aniline molecule.
Related Topics
Physical Sciences and Engineering
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Physical and Theoretical Chemistry
Authors
Pradyot K. Chowdhury,