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采用Gaussian 09软件,利用密度泛函理论和含时密度泛函理论方法,在B3LYP方法和混合基组(Fe(Ⅱ)采用赝式基组Lan2dz;N、O采用6-311++G(2d,p);C、H原子采用6-31G(d))水平对尾式L-苏氨酸卟啉亚铁的ECD谱进行了理论研究。采用Multiwfn和SpecDis程序对Gaussian 09软件的研究结果进一步分析,获得了分子轨道的组成成份,拟合得到了理论ECD谱。研究发现:(1)尾式L-苏氨酸卟啉亚铁在Soret区存在2个CD吸收带,在长波处为正的Cotton效应,在短波处为负的Cotton效应;(2)499 nm附近的CD吸收带(正)主要是由亚铁离子到卟吩环的荷移跃迁d_(FE(Ⅱ))→π_(porphin)~*引起的;(3)449 nm附近的CD吸收带(负)是由卟吩环到亚铁离子和羧基的π_(porphin)→d_(FE(Ⅱ))和π_(porphin)→π_(-COOH)~*荷移跃迁引起的。这些结论对深入理解配合物的手征光学性质具有一定的科学意义。
Using Gaussian 09 software, density functional theory (DFT) and time-dependent density functional theory (DFT) were used in the B3LYP method and the mixed base group (Fe2 + , p); C, H atoms using 6-31G (d)) level of L-threonine porphyrin ferrous porphyrin ECD theoretical study. The results of Gaussian 09 software were further analyzed by using Multiwfn and SpecDis programs. The molecular orbital composition was obtained and the theoretical ECD spectra were obtained. The results showed that: (1) there are two CD absorption bands in the Soret region of the tail L-threonine porphyrin ferrous, and the Cotton effect is a positive Cotton effect at the long wavelength and a negative Cotton effect at the short wavelength. (2) The band near the CD (positive) is mainly caused by the transition of ferrous ions to the porphine ring (FE (Ⅱ) → π porphin); (3) the band around 449 nm Negative) is caused by the transition from porphine ring to porphin → d_ (FE (Ⅱ)) and π porphin → π - (- COOH) ~ * of ferrous ions and carboxyl groups. These conclusions have certain scientific significance for understanding the chiral optical properties of the complex.