系列异构配合物Ru(azpy)2Cl)2的结构与抗癌活性

用量子化学密度泛函(DFT)方法, 在B3LYP/LanL2DZ的水平上, 研究了一系列异构配合物α-, β-, γ-, δ-, ε-Ru(azpy)2Cl2](azpy = 2-phenylazopyridine)(1～5)的电子结构与几何构型, 并着重研究了已报道具有优良抗癌活性的1～3的构效关系(SAR). 计算结果表明, 配合物3的两个共轭配体(azpy)的主体部分几乎处于同一平面上, 有利于插入到DNA碱基对之间. 而配合物1和2的两个共轭配体(azpy)的主体部分几乎相互垂直, 对配合物的DNA插入键合空间位阻较大. 计算结果还进一步显示了该系列异构体配合物的电子结构特征及相关性质. 作为配合物在亲电反应中起主要作用的最低未占据分子轨道(LUMO)的能量顺序为εL(2)＞εL(1)＞εL(3); 与反应活性密切相关的LUMO与最高占据分子轨道(HOMO)之间的能量差(ΔεL-H)顺序为ΔεL-H(3)＜ΔεL-H(1)＜ΔεL-H(2); 反映配合物疏水性的偶极矩顺序为µ(2)＞µ(1)＞µ(3); 此外, 与亲电反应有关的配合物共轭配体azpy上正电荷(QL)顺序为QL(3)＞QL(1)＞QL(2). 同时, 对迄今尚未见抗癌活性报道的同系列其它两个异构配合物(4和5)进行了活性预测.

Structures and Anticancer Activities of a Series of Isomeric Complexes Ru(azpy)2Cl2

The electronic and geometric structures of a series of isomeric complexes α-, β-, γ-, δ-, ε-Ru(azpy)2Cl2](azpy = 2-phenylazopyridine) (1~5) have been systemically studied, using the density functional theory(DFT) method at the B3LYP/LanL2DZ level. In particular, the structure-activity relationship(SAR) of 1~3 reported recently to be well-known antitumors, was emphatically investigated. The computed results show that: (i) The main-body (azopyridine) planes of two conjugative ligands(azpy) in γ-Ru(azpy)2Cl2](3) are almost located on the same plane, it must be advantageous to the conjugative ligand intercalating between DNA-base-pairs, whereas those in α- and β-Ru(azpy)2Cl2](1 and 2) are almost intervertical and thus it must be unadvantageous to their DNA-binding affinities due to their greater steric hindrance. (ii) The energies (εL) of the lowest unoccupied molecular orbitals(LUMO) playing a main role in the electrophilic reaction, are in sequence of εL(2) >εL(1) >εL(3); The energy differences (ΔεL-H) between LUMOs and HOMOs, being closely relative to the reaction activity, are in sequence of ? ΔεL-H(3)<ΔεL-H(1)<ΔεL-H(2). (iii) The total dipole moments (µ) of the isomer, being closely relative to the hydrophobic parameter of the molecule, are in sequence of µ(2) >µ(1) >µ(3). (iv) The positive charges (QL) in the ligand azpy, being also relative to the ability to accept the electron from DNA, are in sequence of QL(3) >QL(1) >QL(2). In addition, based on the above theoretical analytic method, the heretofore unreported antimetastatic activities of the other two isomeric complexes δ-, ε-Ru(azpy)2Cl2](4 and 5) have been predicted.