Zn(II)-Coordination Complex(s) from Chiral Bisamides of L-Phenylalanine: Nanoscale-Based Biological Applications and...

Three 3-pyridyl-containing small organic bisamide molecules attached with innocent L-phenylalanine (PHE) side chain as building blocks and positional isomeric toluoyl terminals (PME, MME, and OME) have rationally been designed and synthesized for developing a new series of Zn^II-coordination complexes. One of the unique molecular frameworks, having two hydrogen bond-equipped monodentate metal-coordinating sites and biologically potent chiral PHE moiety, was combined with Zn^II halide salts under various conditions to produce the coordination complexes (CC1-CC7), thoroughly characterized by the single-crystal X-ray diffraction (SXRD) technique. Maintaining the similar component ratios of acquired CCs in 1:1 DMSO-water produced low-molecular weight metallogels (LMWGs) of PME/MME as envisaged from a rheology- and crystal engineering-based structural rationale. A structure-property correlation from the basis of PXRD of the bulk and xerogels and SXRD data of the isolated single crystals of reaction products clearly supports the crystal engineering-based design strategy based on which the metallogels are prepared. Hand-ground nanoscale ZnCl₂-based coordination complex CC1 of PME was also studied for cytotoxicity (HEK-293 cell line) and anticancer activities (B16-F10 cell line) in the MTT assay.