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Theoretical Investigation on the Substituent Effect of Halogen Atom on the Ground‐State Double Proton Transfer in the 2‐Pyridone‐Solvent (Solvent: H 2 O, NH 3 ) Complexes
Author(s) -
Ni Mei,
Fang Hua
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201802647
Subject(s) - chemistry , halogen , solvent , substituent , molecule , ammonia , dimer , proton , ground state , photochemistry , stereochemistry , organic chemistry , alkyl , physics , quantum mechanics
The substituted effect on the dynamics of ground‐state proton transfer (GSPT) in 2‐pyridone (2PY) clusters mediated by water or ammonia was investigated at the M06‐2X/6‐311+G(d, p) level. The GSPT process via H‐bonded channel was affected by the bridging solvent. When the bridging molecule changes from one water to one ammonia, proton transfer occurs in a concerted pathway, but the reaction mechanism changes from a synchronous pattern to an asynchronously protolytic pattern, which was ascribed to the larger basicity of ammonia with comparison to water. When two water or two ammonia molecules mediated the GSPT process of 2PY, GSPT reaction in both 2PY clusters prefers a concerted but asynchronous protolytic pathway since the basicity of the H‐bonded chain consisting of water or ammonia dimer was accumulated. For the 6X2PY‐H 2 O (X=H, F, Cl, Br) complex, the replacement of halogen atom also changed the GSPT mechanism from concertedly synchronicity to concertedly asynchronicity. However, the GSPT mechanism of 6X2PY‐NH 3 (X=H, F, Cl, Br) complex was not influenced by the substitutents, but the asynchronicity of GSPT was enlarged apparently. The substituted effect also affected the structural parameters and reduced the barrier heights of GSPT.