Prasanta Das, Mohammed Bahou, Yuan-Pern Lee
Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
The Journal of chemical physics 2013 Feb 7With infrared absorption spectra we investigated the reaction between Cl atom and pyridine (C(5)H(5)N) in a para-hydrogen (p-H(2)) matrix. Pyridine and Cl(2) were co-deposited with p-H(2) at 3.2 K; a planar C(5)H(5)N-Cl(2) complex was identified from the observed infrared spectrum of the Cl(2)/C(5)H(5)N/p-H(2) matrix. Upon irradiation at 365 nm to generate Cl atom in situ and annealing at 5.1 K for 3 min to induce secondary reaction, the 1-chloropyridinyl radical (C(5)H(5)N-Cl) was identified as the major product of the reaction Cl + C(5)H(5)N in solid p-H(2); absorption lines at 3075.9, 1449.7, 1200.6, 1148.8, 1069.3, 1017.4, 742.9, and 688.7 cm(-1) were observed. The assignments are based on comparison of observed vibrational wavenumbers and relative IR intensities with those predicted using the B3PW91/6-311++G(2d, 2p) method. The observation of the preferential addition of Cl to the N-site of pyridine to form C(5)H(5)N-Cl radical but not 2-, 3-, or 4-chloropyridine (ClC(5)H(5)N) radicals is consistent with the reported theoretical prediction that formation of the former proceeds via a barrierless path.
Prasanta Das, Mohammed Bahou, Yuan-Pern Lee. Reactions between atomic chlorine and pyridine in solid para-hydrogen: infrared spectrum of the 1-chloropyridinyl (C5H5N-Cl) radical. The Journal of chemical physics. 2013 Feb 7;138(5):054307
PMID: 23406119
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