榮春英　廉世勛　劉述斌

摘要運用密度泛函活性理論研究了香豆素在非極性和極性溶劑中的行為和規(guī)律.結(jié)果表明香豆素的分子結(jié)構(gòu)和活性指數(shù)與溶劑介電常數(shù)ε相關(guān)因子 （ε-1）/（2ε+1）直接關(guān)聯(lián).在非極性和極性溶劑中一些結(jié)構(gòu)參數(shù)和電荷分布數(shù)與該因子成良好的線性關(guān)系，但密度泛函活性指標(biāo)與相關(guān)因子卻存在完全不同的相關(guān)性.在非極性溶劑中它們是線性相關(guān)關(guān)系，而在極性溶劑中它們表現(xiàn)出二次方的相關(guān)性.本文討論了這種行為差異存在的可能內(nèi)在原因，為理解溶劑效應(yīng)對活性指數(shù)的全面影響提供理論依據(jù).

關(guān)鍵詞密度泛函活性理論；溶劑效應(yīng)；香豆素；介電常數(shù)

It is well known that reactivity indices from density functional reactivity theory （DFRT） are conceptually insightful， and have been widely used to study the structural and electronic properties molecules. The electron distribution of a molecule in gas phase will be markedly altered by the presence of solvent surroundings when the molecule is placed into a solvent with a different polarity. Iida et al. [1] investigated systematically the orbital energy shift in polar solvent. Sanjukta et al. studied the unusual behaviors of photophysical properties for coumarin in nonpolar and polar solvents [23]. Chang [4] discussed the DFTbased linear salvation energy relationships for the infrared spectral shifts of aceton in polar and nonpolar organic solvents. Kar et al. [5] studied the influence of aprotic and protic solvents with different dielectric constants on the reactivity of model systems. Recent reviews by Tomasi and Reichardt [67] are available in the literature. However， a systematic study on the changing behaviors of DFRT descriptors in different solvents with different polarity is still lacking.

Scheme 1The structure of the couramin molecule and the serial number of atoms. Carbon， hydrogen and oxygen atoms are denoted by gray， white and red colors， respectively

In this work， we will look into the different behavior of DFRT descriptors in different solvents with different polarity. We choose coumarin as the system to be investigated， which serves as the prototype for aromatic systems with varied dipole moments， as shown in Scheme 1.

Coumarin is of medical importance in clinics as the precursor for several anticoagulants， notably warfarin， and is used as a gain medium in some dye lasers as well. It has a typically conjugated structure， in which the big π structure could be readily polarized by surrounding solvent molecules. We will consider two kinds of solvents， nonpolar and polar. The main goal of this work is to compare different behaviors of DFRT indices in different solvents for coumarin from the conceptual DFT viewpoint， where we will show that significantly different behaviors are observed.

References：

[1]IIDA K， YOKOGAWA D， SATO H， et al. A systematic understanding of orbital energy shift in polar solvent[J]. J Chem Phys， 2009，130（4）：044107.

[2]KUMBHAKAR M. Photophysical properties of coumarin152 and coumarin481 dyes： unusual behavior in nonpolar and in higher polarity solvents [J]. J Phys Chem A， 2003，107（24）：48084816.

[3]NAD S， PAL H. Photophysical properties of coumarin500 （C500）： Unusual behavior in nonpolar solvents[J]. J Phys Chem A， 2003，107（4）：501507.

[4]CHANG C M. DFTbased linear solvation energy relationships for the infrared spectral shifts of acetone in polar and nonpolar organic solvents[J]. J Phys Chem A， 2008，112（11）：24822488.

[5]KAR R， PAL S. Effect of solvents having different dielectric constants on reactivity： A conceptual DFT approach [J]. Inter J Quant Chem， 2010， 110（9）：16421647.

[6]TOMASI J， PERSICO M. Molecular interactions in solution： an overview of methods based on continuous distributions of the solvent [J]. Chem Rev， 1994，94（7）：20272094.

[7]REICHARDT C， WELTON T. Solvents and solvent effects in organic chemistry[M]. Hoboken：John Wiley & Sons， 2011.

[8]PARR R G， DONNELLY R A， LEVY M， et al. Electronegativity： the density functional viewpoint [J]. J Chem Phys， 1978， 68（8）：3801.

[9]ICZKOWSKI R P， MARGRAVE J L. Electronegativity [J]. J Am Chem Soc， 1961，83（17）：35473551.

[10]MULLIKEN R S. A new electroaffinity scale； together with data on valence states and on valence ionization potentials and electron affinities [J]. J Chem Phys， 1934，2（11）：782.

[11]PARR R G， PEARSON R G. Absolute hardness： companion parameter to absolute electronegativity [J]. J Am Chem Soc， 1983，105（26）：75127516.

[12]AYERS P W， PARR R G， PEARSON R G. Elucidating the hard/soft acid/base principle： A perspective based on halfreactions [J]. J Chem Phys， 2006，124（19）：194107.

[13]PARR R G， VON SZENTPALY L， LIU S B. Electrophilicity index [J]. J Am Chem Soc， 1999，105（9）：19221924.

[14]GEERLINGS P， DE PROFT F， LANGENAEKER W. Conceptual density functional theory [J]. Chem Rev， 2003，103（5）：1793873.

[15]CHATTARAJ P K， SARKAR U， ROY D R. Electrophilicity index [J]. Chem Rev， 2006，106（6）：20652091.

[16]LIU S B. Conceptual density functional theory and some recent developments [J]. Acta Phys Chim Sin， 2009，25（3）：590600.

[17]ZHAO D， RONG C， LIAN S， et al. Why zinc？ A density functional reactivity theory study on metalbinding specificity of zincfinger proteins [J]. J Nat Sci Hunan Normal Univ， 2013，36（2）：4448.

[18]FRISCH M J， TRUCKS G W， SCHLEGEL H B， et al. Gaussian 09， revision D.01[CP]. Gaussian Inc.： Wallingford， CT， 2009.

（編輯楊春明）

[2]KUMBHAKAR M. Photophysical properties of coumarin152 and coumarin481 dyes： unusual behavior in nonpolar and in higher polarity solvents [J]. J Phys Chem A， 2003，107（24）：48084816.

[3]NAD S， PAL H. Photophysical properties of coumarin500 （C500）： Unusual behavior in nonpolar solvents[J]. J Phys Chem A， 2003，107（4）：501507.

[4]CHANG C M. DFTbased linear solvation energy relationships for the infrared spectral shifts of acetone in polar and nonpolar organic solvents[J]. J Phys Chem A， 2008，112（11）：24822488.

[5]KAR R， PAL S. Effect of solvents having different dielectric constants on reactivity： A conceptual DFT approach [J]. Inter J Quant Chem， 2010， 110（9）：16421647.

[6]TOMASI J， PERSICO M. Molecular interactions in solution： an overview of methods based on continuous distributions of the solvent [J]. Chem Rev， 1994，94（7）：20272094.

[7]REICHARDT C， WELTON T. Solvents and solvent effects in organic chemistry[M]. Hoboken：John Wiley & Sons， 2011.

[8]PARR R G， DONNELLY R A， LEVY M， et al. Electronegativity： the density functional viewpoint [J]. J Chem Phys， 1978， 68（8）：3801.

[9]ICZKOWSKI R P， MARGRAVE J L. Electronegativity [J]. J Am Chem Soc， 1961，83（17）：35473551.

[10]MULLIKEN R S. A new electroaffinity scale； together with data on valence states and on valence ionization potentials and electron affinities [J]. J Chem Phys， 1934，2（11）：782.

[11]PARR R G， PEARSON R G. Absolute hardness： companion parameter to absolute electronegativity [J]. J Am Chem Soc， 1983，105（26）：75127516.

[12]AYERS P W， PARR R G， PEARSON R G. Elucidating the hard/soft acid/base principle： A perspective based on halfreactions [J]. J Chem Phys， 2006，124（19）：194107.

[13]PARR R G， VON SZENTPALY L， LIU S B. Electrophilicity index [J]. J Am Chem Soc， 1999，105（9）：19221924.

[14]GEERLINGS P， DE PROFT F， LANGENAEKER W. Conceptual density functional theory [J]. Chem Rev， 2003，103（5）：1793873.

[15]CHATTARAJ P K， SARKAR U， ROY D R. Electrophilicity index [J]. Chem Rev， 2006，106（6）：20652091.

[16]LIU S B. Conceptual density functional theory and some recent developments [J]. Acta Phys Chim Sin， 2009，25（3）：590600.

[17]ZHAO D， RONG C， LIAN S， et al. Why zinc？ A density functional reactivity theory study on metalbinding specificity of zincfinger proteins [J]. J Nat Sci Hunan Normal Univ， 2013，36（2）：4448.

[18]FRISCH M J， TRUCKS G W， SCHLEGEL H B， et al. Gaussian 09， revision D.01[CP]. Gaussian Inc.： Wallingford， CT， 2009.

（編輯楊春明）

[2]KUMBHAKAR M. Photophysical properties of coumarin152 and coumarin481 dyes： unusual behavior in nonpolar and in higher polarity solvents [J]. J Phys Chem A， 2003，107（24）：48084816.

[3]NAD S， PAL H. Photophysical properties of coumarin500 （C500）： Unusual behavior in nonpolar solvents[J]. J Phys Chem A， 2003，107（4）：501507.

[4]CHANG C M. DFTbased linear solvation energy relationships for the infrared spectral shifts of acetone in polar and nonpolar organic solvents[J]. J Phys Chem A， 2008，112（11）：24822488.

[5]KAR R， PAL S. Effect of solvents having different dielectric constants on reactivity： A conceptual DFT approach [J]. Inter J Quant Chem， 2010， 110（9）：16421647.

[6]TOMASI J， PERSICO M. Molecular interactions in solution： an overview of methods based on continuous distributions of the solvent [J]. Chem Rev， 1994，94（7）：20272094.

[7]REICHARDT C， WELTON T. Solvents and solvent effects in organic chemistry[M]. Hoboken：John Wiley & Sons， 2011.

[8]PARR R G， DONNELLY R A， LEVY M， et al. Electronegativity： the density functional viewpoint [J]. J Chem Phys， 1978， 68（8）：3801.

[9]ICZKOWSKI R P， MARGRAVE J L. Electronegativity [J]. J Am Chem Soc， 1961，83（17）：35473551.

[10]MULLIKEN R S. A new electroaffinity scale； together with data on valence states and on valence ionization potentials and electron affinities [J]. J Chem Phys， 1934，2（11）：782.

[11]PARR R G， PEARSON R G. Absolute hardness： companion parameter to absolute electronegativity [J]. J Am Chem Soc， 1983，105（26）：75127516.

[12]AYERS P W， PARR R G， PEARSON R G. Elucidating the hard/soft acid/base principle： A perspective based on halfreactions [J]. J Chem Phys， 2006，124（19）：194107.

[13]PARR R G， VON SZENTPALY L， LIU S B. Electrophilicity index [J]. J Am Chem Soc， 1999，105（9）：19221924.

[14]GEERLINGS P， DE PROFT F， LANGENAEKER W. Conceptual density functional theory [J]. Chem Rev， 2003，103（5）：1793873.

[15]CHATTARAJ P K， SARKAR U， ROY D R. Electrophilicity index [J]. Chem Rev， 2006，106（6）：20652091.

[16]LIU S B. Conceptual density functional theory and some recent developments [J]. Acta Phys Chim Sin， 2009，25（3）：590600.

[17]ZHAO D， RONG C， LIAN S， et al. Why zinc？ A density functional reactivity theory study on metalbinding specificity of zincfinger proteins [J]. J Nat Sci Hunan Normal Univ， 2013，36（2）：4448.

[18]FRISCH M J， TRUCKS G W， SCHLEGEL H B， et al. Gaussian 09， revision D.01[CP]. Gaussian Inc.： Wallingford， CT， 2009.

（編輯楊春明）