金属卟吩的给体性质

研究了四-(邻氯苯基)卟吩(OCITPP)和四苯基卟吩(TPP)系列的某些金属络合物在2,4-二硝基氯代苯(DNCB)存在下的可见吸收和荧光光谱, 发现吸收和荧光强度均比金属卟吩单独存在时为低, 表明金属卟吩作为给体, 与π受体DNCB形成分子络合物. OCLTPP系列的金属卟吩, 由于苯环上邻位氯取代降低分子对称性和产生空间阻碍等因素, 使它们与DNCB的络合常数减小, 从而削弱了受体对给体的荧光猝灭作用.

DONOR PROPERTIES OF METALLOPORPHINS

The visible absorption and fluorescence spectra of metallo derivatives of tetrakis- (ortho-chlorophenyl) porphin (OCITPP) and tetraphenylporphin (TPP) in the pre- sence of 2,4—dinitrochlorobenzene (DNCB) have been studied.Both the absorbance and the fluorescence intensity were found to be lower than those of metalloporphins in the absence of DNDB,indicating the formation of molecular complexes between the donor and the π accepter DNCB. Owing to the reduced molecular symmetry and steric hindrance resulted from the monochloro-substitution at the orthophenyl positions, the binding between the donor and the acceptor for metalloporphins of OCITPP series, was weakened, and hence the fluorescence of metallopophins of OCITPP series was less quenched by DNCB than metalloporphins of TPP series.