A novel class of zinc(II)-based metal complexes, i.e., [Zn 2 (acdp)(μ-Cl)]•2H 2 O (1), [Zn 2 (acdp)(μ-NO 3 )]•2H 2 O (2), and [Zn 2 (acdp)(μ-O 2 CCF 3 )]•2H 2 O (3) (Cl − = chloride; NO 3 − = nitrate; CF 3 CO 2 − = trifluoroacetate) of anthracene-affixed multifunctional organic assembly, H 3 acdp (H 3 acdp = N,N′-bis-[anthracene-2-ylmethyl]-N,N′-bis[carboxymethyl]-1,3-diaminopropan-2-ol), have emerged as promising antibacterial and antibiofilm agents in the domain of medicinal chemistry. Accordingly, complexes 1−3 were synthesized by utilizing H 3 acdp in combination with ZnCl 2 , Zn(NO 3 ) 2 •6H 2 O, and Zn(CF 3 CO 2 ) 2 •H 2 O respectively, in the presence of NaOH at ambient temperature.The complexation between H 3 acdp and Zn 2+ was delineated by a combined approach of spectrophotometric and spectrofluorometric titration studies. The stoichiometry of acdp 3− /Zn 2+ in all three complexes is observed to be 1:2, as confirmed by spectrophotometric/spectrofluorometric titration data. Elemental analysis (C, H, N, Zn), molar conductance, FTIR, UV−vis, and thermoanalytical (TGA/DTA) data were effectively used to characterize these complexes. Besides, the structures of 1−3 were established by density functional theory (DFT) calculation using B3LYP/6-311G, specifying a self-assembled compact geometry with average Zn•••Zn separation of 3.4629 Å. All three zinc complexes exhibited significantly high antibacterial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA BAA1717). However, complex 1 showed a more recognizable activity than 2 and 3, with minimum inhibitory concentration (MIC) values of 200, 350, and 450 μg/mL, respectively. The antimicrobial activity was tested by employing the minimum inhibitory concentration (MIC) and time-kill assay. The crystal violet (CV) assay and microscopic study were performed to examine the antibiofilm activity. As observed, complexes 1−3 had an effect on the production of extracellular polymeric substance (EPS), biofilm cell-viability, and other virulence factors such as staphyloxanthin and hemolysin production, autoaggregation ability, and microbial cell-surface hydrophobicity. Reactive oxygen species (ROS) generated due to inhibition of staphyloxanthin production in response to 1−3 were also analyzed. Moreover, complexes 1−3 showed an ability to damage the bacterial cell membrane due to accumulation of ROS resulting in DNA leakage. In addition, complexes 1−3 displayed a synergistic/additive activity with a commercially available antibiotic drug, vancomycin, with enhanced antibacterial activity. On the whole, our investigation disclosed that complex 1 could be a promising drug lead and attract much attention to medicinal chemists compared to 2 and 3 from therapeutic aspects.

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The three discrete [Zn 6 ] c omplexes [Na 3 Zn 6 (cpdp) 3 (μ-Bz) 3 (CH 3 OH) 6 ][ZnCl 4 ][ZnCl 3 (H 2 O)]• 3CH 3 OH•1.5H 2 O (1), [Na 3 Zn 6 (cpdp) 3 (μ-p-OBz) 3 (CH 3 OH) 6 ]• 2H 2 O (2), and [Na 3 Zn 6, have been successfully synthesized and fully characterized (Bz = benzoate; p-OBz = dianion of phydroxybenzoic acid; p-NO 2 Bz = p-nitrobenzoate). The complexes have been characterized by elemental analysis, FTIR, UV−vis, NMR spectroscopy, PXRD, and thermal analysis, including singlecrystal X-ray crystallography of 1 and 2. The molecular architectures of 1−3 are built from the self-assembly of their corresponding [Zn 2 ] units, which are interconnected to the central [Na 3 (CH 3 OH) 6 ] 3+ core by six endogenous benzoate groups, with each linking one Zn(II) and one Na(I) ion in a μ 2 :η 1 :η 1 -syn-anti bidentate fashion. The composition of the (cpdp 3− ) 3 /(Zn 2+ ) 6 complexes in 1−3 has been observed to be 1:2, on the basis of the UV−vis titration and NMR spectroscopic results, which is further supported by Xray crystallography. Systematic biological studies performed with a mice model suggested possible antidiabetic efficacy as well as anticancer activities of the complexes. When complexes 1−3 were administered intraperitoneally in mice, 1 showed a lowering in the blood glucose level, overall maintenance of the pancreatic tissue mass, restriction of DNA damage in pancreatic cells, and retention of lipid droplet (LD) frequency, whereas 2 and 3 showed hepatic tissue mass consistency by inhibiting the DNA damage in hepatic cells, prior to the exposure to a potent diabetic inducer, alloxan (ALX). Similar trends of results were observed in inhibiting the generation of reactive oxygen species (ROS) in the pancreatic and hepatic cells, as examined by spectrofluorometric methods. Thus, 1 seems to be a better compound for overall diabetic management and control, whereas 2 and 3 seem to be promising compounds for designing chemopreventive drugs against hepatic carcinoma.

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Anthracene-affixed carboxylate-rich tridentate ligand containing three new mononuclear complexes, [Cu(acpa)(H 2 O) 2 ]⋅H 2 O (1), [Mn(acpa)(H 2 O) 2 ] (2) and [Zn(acpa)(H 2 O) 2 ] (3) (H 2 acpa = 3-(anthracene-9-ylmethyl-carboxymethyl-amino)-propionic acid), have been synthesized and characterized by various analytical and spectral methods. In methanol, complexes 1-3 have been prepared by carrying out reaction of the ligand H 2 acpa with stoichiometric amounts of CuSO 4 ⋅ 5H 2 O, MnSO 4 ⋅H 2 O and ZnSO 4 ⋅ 7H 2 O respectively, in the presence of NaOH at ambient temperature. The X-ray crystal structure analysis reveals that complex 1 consists of a distorted square pyramidal copper center, coordinated to one acpa 2À ligand in a tridentate manner (N,O,O) and two exogenous water molecules. On the other hand, the molecular structures of complexes 2 and 3, optimized by DFT method indicate that their core arrangements around the metal centers are similar to that of 1. In solution, the coordination phenomena of Cu((II), Mn(II) and Zn(II) ions with the ligand H 2 acpa and the structural features of the complexes have been authenticated by UV-Vis and fluorescence titration experiments. The composition of the M II /acpa 2À complexes (M = Cu, Mn, Zn) in 1-3 has been observed to be 1 : 1, based on the UV-Vis/fluorescence titration results which are further supported by X-ray crystallography and DFT calculation. Complexes 1-3 are investigated for their binding affinity towards Calf Thymus (CT) DNA in solution at pH ∼ 7.5 by UV-Vis and fluorescence spectroscopic methods. From the electronic absorption spectral studies, it has been found that the DNA binding constants of 1-3 are (5.67 � 0.32) × 10 4 M À 1 , (2.35 � 0.26) × 10 4 M À 1 and (2.49 � 0.33) × 10 4 M À 1 , respectively, following the order 1 > 3 > 2. Measurements of viscosity of DNA in the absence and presence of the metal complexes suggest that all three complexes interact with DNA through partial intercalative mode.