Wang Xueli, Lu Ming, Huo Cheng, Li Hongjing, Wang Yue, Li Zhengqiang
Key Laboratory for Molecular Enzymology and Engineering of Educational Ministry, Jilin University, Changchun, Jilin 130021, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Aug 15;73(4):581-6. doi: 10.1016/j.saa.2009.01.012. Epub 2009 Jan 24.
Solutions of meso-tetrakis [3-methoxy-4-(N-carbazyl)n-hexyloxyphenyl] porphyrin (4C6-TPP) in a water-organic mixture (tetrahydrofuran, THF) generate aggregates with absorption spectra characterized by broader red shifts of the Soret band relative to the monomeric porphyrin band. For the aggregated form several phenyl modes enhance and some modes weaken, the nu(2), nu(3) and nu(11) bands in the Raman spectra are slightly downshifted compared with the monomeric form. These data suggest that the phenyl groups of 4C6-TPP in the aggregate rotate to an orientation more coplanar with the porphyrin core. The increased conjugation of the meso-phenyl rings with the porphyrin core brings about the red shift of the Soret band. The circular dichroism (CD) band of the aggregate undergoes some changes with time, as indicated by the transition from a negative band to no signal resulted from the rotation of phenyl groups. All of the results imply that the location of the phenyl groups plays a key role in the determination of the morphology of the aggregate.
中-四[3-甲氧基-4-(N-咔唑基)正己氧基苯基]卟啉(4C6-TPP)在水-有机混合物(四氢呋喃,THF)中的溶液会形成聚集体，其吸收光谱的特征是相对于单体卟啉带，Soret带出现更宽的红移。对于聚集形式，拉曼光谱中的几个苯基模式增强而一些模式减弱，与单体形式相比，ν(2)、ν(3)和ν(11)带略有下移。这些数据表明，聚集体中4C6-TPP的苯基旋转到与卟啉核更共面的取向。中苯基环与卟啉核共轭的增加导致Soret带的红移。聚集体的圆二色性(CD)带随时间发生一些变化，这表现为从负带转变为由于苯基旋转而产生的无信号。所有结果表明，苯基的位置在聚集体形态的确定中起关键作用。
