摘要
用密度泛函理论的B3LYP法,将中位-四[二-(3,4-羧甲氧基)苯基]卟啉及结合Re=O分子的几何构型优化,初步理论研究其前沿轨道和能量等。证明,与单独的卟吩环相比,T_(3,4)CPP的卟吩环平面性良好,环上的结构参数变化很小;Re=O与T_(3,4)CPP卟吩环的结合能明显大于与T_(3,4)CPP侧链羧基的结合能,且前者所形成配合物的稳定性显然高于后者,说明T_(3,4)CPP与^(188)Re=O结合的位点应在卟吩环上,而不在侧链羧基上。T_(3,4)CPP卟吩环结合Re=O而形成配合物的结构参数,与Vicente等Zn-卟啉衍生物的测定值相近。在卟吩环上配位时,T_(3,4)CPP卟吩环上的电荷重新分布,卟吩环碳原子的电子向4个氮原子转移:配位后,卟吩环的几何构型略收缩(0.14 A-0.19 A)和马鞍形扭转(5.7°)。
The molecular structure of meso-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl porphyrin(T_(3,4)CPP) and the combination of Re=O with T34CPP are studied using the DFT(density functional theory) with B3LYP method.Their optimum geometry structures,FMO(foreside molecular orbital) and combination energy are calculated and analyzed.It shows that the porphin ring in T_(3,4)CPP keeps good planarity and exactly similar geometry with separate porphin ring.It also shows that the combination energy of Re=O with T_(3,4)CPP on porphin ring is remarkably higher than that of Re=O with T_(3,4)CPP on carboxymethyleneoxy group of side chain.And stability of the former complex is much higher than that of the latter one. These imply that ^(188)Re=O should be labeled with T_(3,4)CPP on porphin ring while not on carboxymethyleneoxy group of side chain.It still shows that during combination of Re=O with T_(3,4)CPP on porphin ring,electron shifts from carbon atoms to nitrogen atoms.It still shows that after combination of Re=O with T_(3,4)CPP on porphin ring,the porphin ring deviates slightly(5.7 degree) from planarity to Re=O,and four nitrogen atoms slightly expand toward Re=O with the ring diameter deduced by 0.15~0.20 angstrom.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2011年第2期143-146,共4页
Computers and Applied Chemistry
基金
中国工程物理研究院科学技术发展基金(2008B0301022)
核物理与化学研究所科学技术创新基金(2009CX02)