Chemistry Department, Faculty of Science, Sohag University, 82534 Sohag, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 3;117:366-78. doi: 10.1016/j.saa.2013.07.056. Epub 2013 Aug 6.
In recent years, great interest has been focused on Fe(II) Schiff base amino acid complexes as cytotoxic and antitumor drugs. Thus a series of new iron(II) complexes based on Schiff bases amino acids ligands have been designed and synthesized from condensation of 5-bromosalicylaldehyde (bs) and α-amino acids (L-alanine (ala), L-phenylalanine (phala), L-aspartic acid (aspa), L-histidine (his) and L-arginine (arg)). The structure of the investigated iron(II) complexes was elucidated using elemental analyses, infrared, ultraviolet-visible, thermogravimetric analysis, as well as conductivity and magnetic susceptibility measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically. The results suggest that 5-bromosalicylaldehyde amino acid Schiff bases (bs:aa) behave as dibasic tridentate ONO ligands and coordinate to Fe(II) in octahedral geometry according to the general formula [Fe(bs:aa)2]·nH2O. The conductivity values between 37 and 64 ohm(-1) mol(-1) cm(2) in ethanol imply the presence of nonelectrolyte species. The structure of the complexes was validated using quantum mechanics calculations based on accurate DFT methods. Geometry optimization of the Fe-Schiff base amino acid complexes showed that all complexes had octahedral coordination. In addition, the interaction of these complexes with (CT-DNA) was investigated at pH=7.2, by using UV-vis absorption, viscosity and agarose gel electrophoresis measurements. Results indicated that the investigated complexes strongly bind to calf thymus DNA via intercalative mode and showed a different DNA binding according to the sequence: bsari>bshi>bsali>bsasi>bsphali. Moreover, the prepared compounds are screened for their in vitro antibacterial and antifungal activity against three types of bacteria, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus and three types of anti fungal cultures, Penicillium purpurogenium, Aspergillus flavus and Trichotheium rosium. The results of these studies indicated that the metal complexes exhibit a stronger antibacterial and antifungal efficiency than their corresponding Schiff base amino acid ligands.
近年来，人们对 Fe(II)Schiff 碱基氨基酸配合物作为细胞毒性和抗肿瘤药物产生了浓厚的兴趣。因此，设计并合成了一系列新型铁(II)配合物，这些配合物基于 Schiff 碱基氨基酸配体，是由 5-溴水杨醛（bs）和α-氨基酸（L-丙氨酸（ala）、L-苯丙氨酸（phala）、L-天冬氨酸（aspa）、L-组氨酸（his）和 L-精氨酸（arg））缩合而成。通过元素分析、红外、紫外-可见、热重分析以及电导率和磁化率测量，阐明了所研究的铁(II)配合物的结构。此外，还通过分光光度法确定了配合物的化学计量和稳定常数。结果表明，5-溴水杨醛氨基酸 Schiff 碱（bs:aa）作为二价三齿 ONO 配体，根据通式[Fe(bs:aa)2]·nH2O 以八面体几何构型与 Fe(II)配位。在乙醇中的电导率值在 37 到 64 ohm(-1) mol(-1) cm(2)之间，表明存在非电解质物质。配合物的结构通过基于精确 DFT 方法的量子力学计算得到验证。Fe-Schiff 碱基氨基酸配合物的几何优化表明，所有配合物都具有八面体配位。此外，还通过紫外-可见吸收、粘度和琼脂糖凝胶电泳测量研究了这些配合物与（CT-DNA）的相互作用。结果表明，在所研究的配合物通过嵌入模式与小牛胸腺 DNA 强烈结合，并根据序列显示出不同的 DNA 结合：bsari>bshi>bsali>bsasi>bsphali。此外，还对这些化合物进行了体外抗菌和抗真菌活性筛选，以对抗三种类型的细菌，大肠杆菌、铜绿假单胞菌和蜡样芽孢杆菌，以及三种类型的抗真菌培养物，藤黄微球菌、黄曲霉和红曲霉。这些研究的结果表明，金属配合物比其相应的 Schiff 碱基氨基酸配体具有更强的抗菌和抗真菌效率。
