1，8，15，22-四(3-戊氧基)自由酞菁的结构、性质和红外光谱研究

The Structure and Properties of Metal-Free 1,8,15,22-Tetrakis(3-Pentyloxy) Phthalocyanine Complex and Study of Its IR spectra

利用密度泛函理论(DFT)中的B3LYP方法,在6-31G(d)基组水平上对1,8,15,22-四(3-戊氧基)自由酞菁的分子结构、分子轨道、原子电荷分布和红外光谱进行了研究。对酞菁骨架结构计算的键长和晶体结构相差最大仅0.002 nm,最小的不足0.000 3 nm,表明了计算的酞菁骨架结构与晶体数据很吻合;对实验红外光谱图上的峰和模拟的峰的波数进行对应线性拟合,得出拟合直线的斜率为1.039,截距为58 cm-1,说明计算的红外光谱和实验测得的对应得非常好。上述结果验证了所选取的理论方法和基组的可靠性。通过与未取代自由酞菁结构和性质的比较,发现烷氧基取代后的酞菁分子中原子电荷仍然主要分布在酞菁环的内部,烷氧基的氧原子也带有较多负电荷。但是α-位烷氧基取代对整个酞菁分子结构和性质都产生很大的影响,烷氧基取代升高了HOMO和LUMO的能量,降低了HOMO-LUMO能级,从而降低了其稳定性。借助正则坐标分析,对红外光谱中的重要吸收峰进行了详细的指认。

Density functional theory calculations were carried out to study the molecular structure, molecular orbital, atomic charge, and infrared spectra of metal-free 1,8,15,22-tetrakis（3-pentyloxy） phthalocyanine using B3LYP method with the 6-31G （d） basis set. The optimized molecular geometry is in good agreement with the result from X-ray deterimination, and the differ- ences between the bond lengths from calculation and X-ray crystallography structure for the framework of phthalocyanine are less than 0. 002 nrn. It was also found that there is a good consistency between the calculated and experimental IR data. The calculated structure and IR spectra were fairly compared with the X-ray crystallography structure and experimental IR spectra to verify the reliability of employed B3LYP method and 6-31G（d） basis set. It is worth noting that the 3-pentyloxy groups at the alpha position have significant influence on the structure and properties of metal-free pthalocyanine, for example, both the energies of HOMO and LUMO increase, however, the gap between HOMO and LUMO decreases, which results in the decrease of the 1,8,15,22-tetrakis（3- pentyloxy）phthalocyanine stability. The important peaks in the IR spectra were also assigned and analyzed in detail according to the calculations.