Nanometer‐sized, rod‐like, ligand‐containing tryptophan complexes: Anion influence–structural geometry–antitumor activity correlations

Matrix metalloproteinases (MMPs) are metal‐dependent endopeptidases that are related to the initiation and progression of diseases and are involved in physiological processes such as angiogenesis, wound healing, and embryonic development. Synthetic inhibitors of MMPs are amino acid–based ligands as analyzed by the interactions between the enzyme and its natural substrate. Low production cost and low environmental toxicity of α‐amino acid complexes resulted in a wide pharmacological spectrum, including the anti‐inflammatory and anticonvulsant properties in addition to cytotoxic activities. These facts directed our search for the development of selective inhibitors that contain chemical entity. l‐Tryptophan is a main component of proteins and is essential in human nutrition for establishing and sustaining positive nitrogen balance. Nanomaterials exhibited clinical influence in terms of delivery approaches on bioactive molecules as therapeutic and imaging contrast agents. In this article, we report the synthesis of nanometer rod‐like 2,2′‐(1,3,5,7‐tetraoxopyrrolo[3,4‐f]isoindole‐2,6(1H,3H,5H,7H)‐diyl)bis(3‐(1H‐indol‐3‐yl)propanoic acid) and its metal complexes. The effect of different anions on the geometrical structures and properties of several complexes was studied. Studies indicated that most complexes exhibited dinuclear octahedral or tetrahedral topologies with M–M interaction being absent, whereas mononuclear square planar or square pyramidal topologies were obtained for copper complexes containing chloride or nitrate anions. The ligand exhibited its activity solely against Bacillus subtilis. [Co2(L)Cl2(H2O)2] complex exhibited potent activity against various species of pathogenic microorganisms. The cytotoxicity against MCF‐7 cell line demonstrated that the inhibitory effect is dose dependent. [Cu(HL)Cl.H2O] complex exhibited an interesting cytotoxic activity in addition to copper anticancer analogues, the alternatives to cis‐platin because of their biocompatibility and important roles in biological systems. The synthesis of nanometer rod‐like 2,2′‐(1,3,5,7‐tetraoxopyrrolo[3,4‐f]isoindole‐2,6(1H,3H,5H,7H)‐diyl)bis(3‐(1H‐indol‐3‐yl)propanoic acid) and its metal complexes was described. The influence of different anions on the geometry of complexes was studied. Studies indicated that most complexes exhibited dinuclear octahedral or tetrahedral topologies, whereas mononuclear square planar or square pyramidal topologies were obtained for copper complexes