计算机与应用化学
計算機與應用化學
계산궤여응용화학
COMPUTERS AND APPLIED CHEMISTRY
2015年
4期
477-479
,共3页
四苯基卟啉镁%电子结构%光谱性质%理论研究
四苯基卟啉鎂%電子結構%光譜性質%理論研究
사분기계람미%전자결구%광보성질%이론연구
MgTPP%electronic structure%spectrum properties%theoretical study
采用密度泛函理论方法在B3LYP和混合基组（C、H原子采用6-31G(d)；Mg、N、O采用6-311++G(2d, p)）水平对含L-苏氨酸侧链的四苯基卟啉镁衍生物L-Thr-TPPMg的基态几何构型进行了优化，获得了稳定的分子构型。以获得的稳定构型为基础，在相同基组水平进行了红外吸收光谱研究；采用含时密度泛函理论方法，在相同基组水平进行了紫外吸收光谱和电子圆二色谱研究。理论研究发现：(1) L-苏氨酸的羧基氧原子与镁原子之间存在配位作用。(2)氮镁配位键、氧镁配位键的伸缩振动在IR谱中的1022 cm-1、278 cm-1处呈现特征吸收峰。(3)理论UV谱存在Soret带和Q带吸收。Q带吸收峰主要由HOMO→LUMO的荷移跃迁贡献；Soret带的吸收峰主要由HOMO-1→LUMO的荷移跃迁贡献。(4) Soret区表现出分裂的ECD谱。第1 Cotton效应主要来源于分子由HOMO-1→LUMO的荷移跃迁；第2 Cotton效应主要由HOMO-1→LUMO+1的荷移跃迁贡献。上述跃迁均为π→π*的荷移跃迁。
採用密度汎函理論方法在B3LYP和混閤基組（C、H原子採用6-31G(d)；Mg、N、O採用6-311++G(2d, p)）水平對含L-囌氨痠側鏈的四苯基卟啉鎂衍生物L-Thr-TPPMg的基態幾何構型進行瞭優化，穫得瞭穩定的分子構型。以穫得的穩定構型為基礎，在相同基組水平進行瞭紅外吸收光譜研究；採用含時密度汎函理論方法，在相同基組水平進行瞭紫外吸收光譜和電子圓二色譜研究。理論研究髮現：(1) L-囌氨痠的羧基氧原子與鎂原子之間存在配位作用。(2)氮鎂配位鍵、氧鎂配位鍵的伸縮振動在IR譜中的1022 cm-1、278 cm-1處呈現特徵吸收峰。(3)理論UV譜存在Soret帶和Q帶吸收。Q帶吸收峰主要由HOMO→LUMO的荷移躍遷貢獻；Soret帶的吸收峰主要由HOMO-1→LUMO的荷移躍遷貢獻。(4) Soret區錶現齣分裂的ECD譜。第1 Cotton效應主要來源于分子由HOMO-1→LUMO的荷移躍遷；第2 Cotton效應主要由HOMO-1→LUMO+1的荷移躍遷貢獻。上述躍遷均為π→π*的荷移躍遷。
채용밀도범함이론방법재B3LYP화혼합기조（C、H원자채용6-31G(d)；Mg、N、O채용6-311++G(2d, p)）수평대함L-소안산측련적사분기계람미연생물L-Thr-TPPMg적기태궤하구형진행료우화，획득료은정적분자구형。이획득적은정구형위기출，재상동기조수평진행료홍외흡수광보연구；채용함시밀도범함이론방법，재상동기조수평진행료자외흡수광보화전자원이색보연구。이론연구발현：(1) L-소안산적최기양원자여미원자지간존재배위작용。(2)담미배위건、양미배위건적신축진동재IR보중적1022 cm-1、278 cm-1처정현특정흡수봉。(3)이론UV보존재Soret대화Q대흡수。Q대흡수봉주요유HOMO→LUMO적하이약천공헌；Soret대적흡수봉주요유HOMO-1→LUMO적하이약천공헌。(4) Soret구표현출분렬적ECD보。제1 Cotton효응주요래원우분자유HOMO-1→LUMO적하이약천；제2 Cotton효응주요유HOMO-1→LUMO+1적하이약천공헌。상술약천균위π→π*적하이약천。
The geometry of L-Thr-TPPMg was optimized using density functional theory (DFT) at the B3LYP level with the mixed basis sets: 6-31G(d) for C and H atoms, and 6-311++G(2d, p) for Mg, N and O atoms. Based on the optimized geometry, the IR spectrum was obtained from the calculated frequencies at the same level. Besides, the UV and ECD spectra were calculated using time-dependent density functional theory (TD-DFT) with the same functional and basis sets. The bond length between O(6) and Mg(1) indicates the coordination effect between Mg atom and the O atom of carbonyl group in L-threonine. The coordination bond between N atom and Mg atom have absorption peak in the 1022 cm-1, and the coordination bond between O atom and Mg atom have absorption peak in the 278 cm-1 in IR spectrum. In the UV spectrum, the absorption peak in Soret band is caused by theπ→π* charge transfer transition from HOMO-1 to LUMO, and the absorption peak in Q band is caused by theπ→π* charge transfer transition from HOMO to LUMO. Detailed analyses of the dominant transitions reveal that all the cotton effects in the ECD spectrum are caused by theπ→π* charge transfer transition. The NO.1 circular dichroism band is dominated by the intermolecular charge transfer transition from HOMO-1 to LUMO, and the NO.2 circular dichroism band is dominated by the intermolecular charge transfer transition from HOMO-1 to LUMO+1.
