溶液態互變異構偶/複合體的計算研究

Calculation Study of Tautomeric Dimer/Complex in Solution Phase

洪發財(Fa-Tsai Hung)

《化學》 55卷4期 (1997/12) Pp. 95-104

https://doi.org/10.6623/chem.1997052

摘要

藉由初始分子軌域計算方法(ab initio molecular calculation) 研究2-pyridone, (PD) 與2-hydroxy pyridine, (HP)的偶合體(dimer)，及PD/HP的復合體(complex)經由共軛雙氫鍵。(conjugated dual hydrogen-bonding, CDHB)促成的互變異構平衡(tautomeric equilibria)。這些結果再結合半經驗的溶解自由能(solvation free energy)計算，可合理地預測在氣態及液態的相對自由能，與存在於PD、HP單體及其偶合體複合體的互變異構平衡現象。這些結果也指出雙氫鍵強度，藉由CDHB 影響PD 、HP 的電子形狀，產生額外的穩定能量；進一步計算顯示PD、HP與其他分子所形成的雙氫鍵複合體，會調整互變異構平衡。

關鍵字

互變異構偶/複合體 ； 溶解自由能 ； 共軛雙氫鍵

並列摘要

Tautomeric equilibria of 2-pyridone (PD ) and 2-hydroxypyridine (HP) dimer as well as PDIHP complex mediated by the conjugated dual hydrogen-bonding (CDHB) formation have been studied by abinitio molecular orbital calculation. The result in combination with the semi-empirical solvation free-energy calculation reasonably predicts the relative free energy and consequently the tautomeric equilibria between PD, HP, their corresponding dimers and PDIHP complex in gas phase as well as in solution phase. The results also indicate that the strength of dual hydrogen bonding resonantly affect the PD and HP electronic structures upon CDHB formation, resulting in an additional stabilization energy. Further calculation shows that the tautomeric equilibria can be fine tuned by the formation of ahydrogen-bonding complex with guest molecules possessing bifunctional hydrogen bonds.

並列關鍵字

Tautomeric Dimer/Complex ； Solvation Free-Energy Calculation ； Conjugated Dual Hydrogen-Bonding