理論探討酚與過渡金屬形成錯合物對酚的酸性的影響

Computational Study of Effect on Acidity of Phenol Attached to Transition Metal Complex Compounds

蔡明松(Ming-Sung Tsai)

《慈惠學報》 13期 (2017/12) Pp. 114-124

https://doi.org/10.6202/THJ.201712_(13).0009

摘要

本研究係利用密度泛函數理論(density functional theory, DFT)針對酚、對硝基酚及酚配位到Cr(CO)_3、Cr(C_6H_6)、Mn(CO)_2NO、Mn(I)(CO)_3、Fe(CO)_2、Fe(II)(CO)_3形成錯合物的絕對酸性進行理論計算，所有分子結構在B3LYP/6-31G*及B3LYP/6-31G**的層次下進行幾何優選(optimization)。取代基效應經由計算出的O-H鍵不均勻斷裂反應及O-H鍵的鍵級分析。結果發現硝基(-NO_2)與過渡金屬[Cr(CO)_3、Cr(C_6H_6)、Mn(CO)_2NO、Mn(I)(CO)_3、Fe(CO)_2、Fe(II)(CO)_3]都具有提高酚的酸性。也就是說Cr(CO)_3、Cr(C_6H_6)、Mn(CO)_2NO、Mn(I)(CO)_3、Fe(CO)_2、Fe(II)(CO)_3和硝基(-NO_2)相似，對酚都具有拉電子的效應。

關鍵字

密度泛函數理論 ； 酚 ； 絕對酸性 ； 拉電子取代基 ； 共振效應

並列摘要

The acidity of phenol attached to transition metal complex compound was examined using the density functional theory calculations. All of the structures were completely optimized at B3LYP/6-31G* and B3LYP/6-31G** level of theory. The absolute acidity were examined by estimating their heterolytic bond dissociation reaction of O-H bond. The main finding of this work reveal that the phenol complexed to transition metal is stronger than the free phenol, suggesting that Cr(CO)_3、Cr(C_6H_6)、Mn(CO)_2NO、[Mn(CO)3]^+、Fe(CO)_2、[Fe(CO)_3]^(2+) act as an electron-withdrawing substituent.

並列關鍵字

density functional theory(DFT) ； phenol ； absolute acidity ； electron-withdrawing substituent ； mesomeric effect

參考文獻

Morrison, R.T. ＆ Boyd, R.N. (1985). 有機化學 (第四版) (楊寶旺、田憲儒譯)。臺北市：東華書局。

Solomons, T.W.G., Fryhle, C.B., ＆Snyder, S.A. (2012). Organic Chemistry (11thed). Hoboken, NJ：John Wiley & Sons。

科學 Online (2010) 苯酚(phenol) 。 取自 http://highscope.ch.ntu.edu.tw/wordpress/?p=8523

Miessler, C.L. ＆ Tarr, D.A. (2004). Inorganic Chemistry 3rd edition. New Jersey: Pearson Prentice Hall.

Hehre, W.J. (2010). Spartan version 10 Wavefunction, CA: Irvin,.