荣春英　廉世勋　刘述斌

摘要运用密度泛函活性理论研究了香豆素在非极性和极性溶剂中的行为和规律.结果表明香豆素的分子结构和活性指数与溶剂介电常数ε相关因子 （ε-1）/（2ε+1）直接关联.在非极性和极性溶剂中一些结构参数和电荷分布数与该因子成良好的线性关系，但密度泛函活性指标与相关因子却存在完全不同的相关性.在非极性溶剂中它们是线性相关关系，而在极性溶剂中它们表现出二次方的相关性.本文讨论了这种行为差异存在的可能内在原因，为理解溶剂效应对活性指数的全面影响提供理论依据.

关键词密度泛函活性理论；溶剂效应；香豆素；介电常数

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.

（编辑杨春明）

[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.

（编辑杨春明）

[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.

（编辑杨春明）