摘要 : Charge-transfer (CT) complexes of some pyrazoles with iodine as a sigma-electron acceptor and with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetracyanoethylene (TCNE), chloranil (CHL) as a pi-electron acceptors were investi... 展开 Charge-transfer (CT) complexes of some pyrazoles with iodine as a sigma-electron acceptor and with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetracyanoethylene (TCNE), chloranil (CHL) as a pi-electron acceptors were investigated spectroscopically. The spectral characteristics and stability constants of the formed 1: 1 CT complexes were examined and discussed in terms of the donor molecular structure, the nature of the electron acceptor as well as the solvent polarity. It is deduced that the complexes with iodine exist in the ionic structure (pyrazole)2 I+.I-3(-) whereas the complex with DDQ is mainly in the dissociated state (radical cation and anion; pyrazole(.+), DDQ(.-)). On the other hand pyrazoles-TCNE, -CHL complexes are essentially of the nonbonding type (pyrazole-TCNE, -CHL). Moreover, it is concluded that the solvent polarity plays an important role in determining the stability of these kinds of CT complex. The ionization potentials of the donors were calculated based on the CT transition energies of their complexes. [References: 54] 收起