Structure elucidation {spectroscopic, single crystal X-ray diffraction and computational DFT studies} of new tailored benzenesulfonamide derived Schiff base copper(II) intercalating complexes: Comprehensive biological profile {DNA binding, pBR322 DNA cleavage, Topo I inhibition and cytotoxic activity}

Copper and Copper Complexes in Tumor Therapy

Copper (Cu), a crucial trace element in physiological processes, has garnered significant interest for its involvement in cancer progression and potential therapeutic applications. The regulation of cellular copper levels is essential for maintaining copper homeostasis, as imbalances can lead to toxicity and cell death. The development of drugs that target copper homeostasis has emerged as a promising strategy for anticancer treatment, with a particular focus on copper chelators, copper ionophores, and novel copper complexes. Recent research has also investigated the potential of copper complexes in cancer therapy.

Identification of FTY720 and COH29 as novel topoisomerase I catalytic inhibitors by experimental and computational studies

The development of novel topoisomerase I (TOP1) inhibitors is crucial for overcoming the drawbacks and limitations of current TOP1 poisons. Here, we identified two potential TOP1 inhibitors, namely, FTY720 (a sphingosine 1-phosphate antagonist) and COH29 (a ribonucleotide reductase inhibitor), through experimental screening of known active compounds. Biological experiments verified that FTY720 and COH29 were nonintercalative TOP1 catalytic inhibitors that did not induce the formation of DNA-TOP1 covalent complexes. Molecular docking revealed that FTY720 and COH29 interacted favorably with TOP1. Molecular dynamics simulations revealed that FTY720 and COH29 could affect the catalytic domain of TOP1, thus resulting in altered DNA-binding cavity size. The alanine scanning and interaction entropy identified Arg536 as a hotspot residue. In addition, the bioinformatics analysis predicted that FTY720 and COH29 could be effective in treating malignant breast tumors. Biological experiments verified their antitumor activities using MCF-7 breast cancer cells. Their combinatory effects with TOP1 poisons were also investigated. Further, FTY720 and COH29 were found to cause less DNA damage compared with TOP1 poisons. The findings provide reliable lead compounds for the development of novel TOP1 catalytic inhibitors and offer new insights into the potential clinical applications of FTY720 and COH29 in targeting TOP1.

Synthesis, crystal structure and in-silico evaluation of arylsulfonamide Schiff bases for potential activity against colon cancer

This report presents a comprehensive investigation into the synthesis and characterization of Schiff base compounds derived from benzenesulfonamide. The synthesis process, involved the reaction between N-cycloamino-2-sulfanilamide and various substituted o-salicylaldehydes, resulted in a set of compounds that were subjected to rigorous characterization using advanced spectral techniques, including 1H NMR, 13C NMR and FT-IR spectroscopy, and single-crystal X-ray diffraction. Furthermore, an in-depth assessment of the synthesized compounds was conducted through Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) analysis, in conjunction with docking studies, to elucidate their pharmacokinetic profiles and potential. Impressively, the ADMET analysis showcased encouraging drug-likeness properties of the newly synthesized Schiff bases. These computational findings were substantiated by molecular properties derived from density functional theory (DFT) calculations using the B3LYP/6-31G* method within the Jaguar Module of Schrödinger 2023-2 from Maestro (Schrodinger LLC, New York, USA). The exploration of frontier molecular orbitals (HOMO and LUMO) enabled the computation of global reactivity descriptors (GRDs), encompassing charge separation (Egap) and global softness (S). Notably, within this analysis, one Schiff base, namely, 4-bromo-2-{N-[2-(pyrrolidine-1-sulfonyl)phenyl]carboximidoyl}phenol, 20, emerged with the smallest charge separation (ΔEgap = 3.5780 eV), signifying heightened potential for biological properties. Conversely, 4-bromo-2-{N-[2-(piperidine-1-sulfonyl)phenyl]carboximidoyl}phenol, 17, exhibited the largest charge separation (ΔEgap = 4.9242 eV), implying a relatively lower propensity for biological activity. Moreover, the synthesized Schiff bases displayed remarkeable inhibition of tankyrase poly(ADP-ribose) polymerase enzymes, integral in colon cancer, surpassing the efficacy of a standard drug used for the same purpose. Additionally, their bioavailability scores aligned closely with established medications such as trifluridine and 5-fluorouracil. The exploration of molecular electrostatic potential through colour mapping delved into the electronic behaviour and reactivity tendencies intrinsic to this diverse range of molecules.

Synthesis, characterization, and cytotoxic effects of new copper complexes using Schiff-base derivatives from natural sources

Copper(II) complexes are interesting for cancer treatment due to their unique properties, including their redox potential, possible coordination structures with different ligands, the most diverse geometries, and different biomolecule reactivity. The present work synthesized new copper(II) complexes with Schiff-base (imine) type ligands using natural aldehydes such as cinnamaldehyde, vanillin, or ethyl vanillin. The ligands were obtained through the reaction of these aldehydes with the amines 1,3-diaminopropane, 2,2-dimethyl-1,3-propanediamine, or 1,3-diamino-2-propanol and characterized by 1H and 13C NMR, FTIR and ESI-HRMS. The complexation reaction used copper(II) as perchlorate salt, obtaining six new copper(II) complexes. The complexes were characterized using FTIR, UV-vis, elemental analysis, ESI-HRMS, and EPR. In addition, the interaction with the copper(II) complexes and serum albumin was investigated by electronic absorption, showing complex incorporation in the albumin structure. The cytotoxicity of the complexes was evaluated using MTT assay in neuroblastoma cell lines SH-SY5Y, CHP 212, and glioblastoma LN-18, and presented EC50 values between 90 and 300 μM. Based on our results, a square-planar copper(II) complex derived from Schiff-base cinnamaldehyde was found here to possess significant potential as an anti-cancer treatment. Further investigation is required to explore this compound's benefits in cancer co-treatment approaches fully.

Combining Copper and Zinc into a Biosensor for Anti-Chemoresistance and Achieving Osteosarcoma Therapeutic Efficacy

Due to its built-up chemoresistance after prolonged usage, the demand for replacing platinum in metal-based drugs (MBD) is rising. The first MBD approved by the FDA for cancer therapy was cisplatin in 1978. Even after nearly four and a half decades of trials, there has been no significant improvement in osteosarcoma (OS) therapy. In fact, many MBD have been developed, but the chemoresistance problem raised by platinum remains unresolved. This motivates us to elucidate the possibilities of the copper and zinc (CuZn) combination to replace platinum in MBD. Thus, the anti-chemoresistance properties of CuZn and their physiological functions for OS therapy are highlighted. Herein, we summarise their chelators, main organic solvents, and ligand functions in their structures that are involved in anti-chemoresistance properties. Through this review, it is rational to discuss their ligands' roles as biosensors in drug delivery systems. Hereafter, an in-depth understanding of their redox and photoactive function relationships is provided. The disadvantage is that the other functions of biosensors cannot be elaborated on here. As a result, this review is being developed, which is expected to intensify OS drugs with higher cure rates. Nonetheless, this advancement intends to solve the major chemoresistance obstacle towards clinical efficacy.

Ruthenium(II)-Dithiocarbazates as Anticancer Agents: Synthesis, Solution Behavior, and Mitochondria-Targeted Apoptotic Cell Death

The reaction of the Ru(PPh₃ )₃ Cl₂ with HL^1-3 -OH (-OH stands for the oxime hydroxyl group; HL¹ -OH=diacetylmonoxime-S-benzyldithiocarbazonate; HL² -OH=diacetylmonoxime-S-(4-methyl)benzyldithiocarbazonate; and HL³ -OH=diacetylmonoxime-S-(4-chloro)benzyl-dithiocarbazonate) gives three new ruthenium complexes [Ru^II (L^1-3 -H)(PPh₃ )₂ Cl] (1-3) (-H stands for imine hydrogen) coordinated with dithiocarbazate imine as the final products. All ruthenium(II) complexes (1-3) have been characterized by elemental (CHNS) analyses, IR, UV-vis, NMR (¹ H, ¹³ C, and ³¹ P) spectroscopy, HR-ESI-MS spectrometry and also, the structure of 1-2 was further confirmed by single crystal X-ray crystallography. The solution/aqueous stability, hydrophobicity, DNA interactions, and cell viability studies of 1-3 against HeLa, HT-29, and NIH-3T3 cell lines were performed. Cell viability results suggested 3 being the most cytotoxic of the series with IC₅₀ 6.9±0.2 μM against HeLa cells. Further, an apoptotic mechanism of cell death was confirmed by cell cycle analysis and Annexin V-FITC/PI double staining techniques. In this regard, the live cell confocal microscopy results revealed that compounds primarily target the mitochondria against HeLa, and HT-29 cell lines. Moreover, these ruthenium complexes elevate the ROS level by inducing mitochondria targeting apoptotic cell death.

Study of Interactions Between 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine and Human DNA by Theoretical, Spectroscopic and Viscometric measurements

From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO-LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C_7, C₉ and C₁₈ as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.

Comprehensive Assessment of Biomolecular Interactions of Morpholine-Based Mixed Ligand Cu(II) and Zn(II) Complexes of 2,2'-Bipyridine as Potential Anticancer and SARS-CoV-2 Agents: A Synergistic Experimental and Structure-Based Virtual Screening

A new class of pharmacologically active mixed-ligand complexes (1a-2a) [M^II(L)₂ (bpy)], where L = 2-(4-morpholinobenzylideneamino)phenol), bpy = 2,2'-bipyridine, M^II = Cu (1a), and Zn (2a), were assigned an octahedral geometry by analytical and spectral measurements. Gel electrophoresis showed that complex (1a) demonstrated the complete DNA cleavage mediated by H₂O₂. The overall DNA-binding constants observed from UV-vis, fluorometric, hydrodynamic, and electrochemical titrations were in the following sequence: (1a) > (2a) > (HL), which suggests that the complexes might intercalate DNA, a possibility that is further supported by the biothermodynamic characteristics. The binding constant results of BSA by electronic absorption and fluorometric titration demonstrate that complex (1a) exhibits the highest binding effectiveness among others, which means that all compounds could interact with BSA through a static approach, additionally supported by FRET measurements. Density FunctionalTheory (DFT) and molecular docking calculations were relied on to unveil the electronic structure, reactivity, and interacting capability of all substances with DNA, BSA, and SARS-CoV-2 main protease (Mpro). These observed binding energies fell within the following ranges: -7.7 to -8.6, -7.2 to -10.2, and -6.7 to -8.2 kcal/mol, respectively. The higher reactivity of the complexes compared to free ligand is supported by the Frontier MolecularOrbital (FMO) theory. The in vitro antibacterial, cytotoxic, and radical scavenging characteristics revealed that complex (1a) has the best biological efficacy compared to others. This is encouraged because all experimental findings are closely correlated with the theoretical measurements.

Spectro-electrochemical, fluorometric and biothermodynamic evaluation of pharmacologically active morpholine scaffold single crystal ligand and its metal(II) complexes: A comparative study on in-vitro and in-silico screening towards DNA/BSA/SARS-CoV-19

A novel series of metal(II) complexes (1-5) [M^II(L)₂]{Where M = Cu (1), Co (2), Mn (3), Ni (4) and Zn (5)} constructed from 2-(4-morpholinobenzylideneamino)phenol Schiff base ligand (HL) in a 1:2 M ratio and the spectral and analytical results put forward square planar geometry. Spectro-electrochemical, hydrodynamic, gel electrophoresis, and DNA binding/cleavage results for all the compounds demonstrate that complex (1) had excellent DNA binding/cleavage properties compared to other compounds. The observation also suggests that test compounds could intercalate with DNA, and the biothermodynamic property more strongly supports the stabilizing of the double helix DNA with the complexes. BSA binding constant results show that complex (1) exposes the best binding property via a static mode, which is further confirmed by FRET calculations. The DFT calculations and docking results for all compounds towards DNA, BSA and SARS-CoV-19 main protease (3CLPro), reveal the binding energies were in the range of -7.8 to -9.4, -6.6 to -10.2 and - 6.1 - -8.2 kcal/mol for all test compounds respectively. In this case, complexes showed favorable binding energies compared to free ligand, which stimulates further studies aimed at validating the predicted activity as well as contributing to tackling the current and future viral pandemics. The in-vitro antioxidant, antimicrobial, and anticancer results for all compounds revealed that copper complex (1) has better activity compared to others. This might result in an effective anticancer drug for future research, which is especially promising since the observed experimental results for all cases were in close agreement with the theoretical calculations.

Three metal complexes with a pyridyl Schiff base: cytotoxicity, migration and mechanism of apoptosis

Three metal complexes [CuL(NO₃)]_n (1), [Cd(HL)(NO₃)₂]_n (2) and [EuL(HCOOH)(H₂O)(NO₃)₂] (3) were synthesized with a pyridyl Schiff ligand L (N'-[(1E)-pyridin-2-ylmethylidene]pyridine-4-carbohydrazide). A crystallographic study revealed that complexes 1 and 2 have a chain structure, and complex 3 is a zero-dimensional monomer. In vitro cytotoxicity studies showed that complex 2 had the best antiproliferative activity against SMMC-7721 cells and complex 3 had the best antiproliferative activity against MDA-MB-231 cells with single-digit IC₅₀ values, both exceeding those of the control drug cisplatin by far. The cell invasion and migration ability through the transwell assay and wound-healing assay showed that the selected complexes could inhibit the invasion and migration of cancer cells. The Hoechst staining assay and ROS generation assay with SMMC-7721 cells indicated that the cytotoxic effects of complex 2 involved apoptosis induction through ROS accumulation. The apoptosis-inducing and cell cycle arrest effects of complex 2 on SMMC-7721 cells indicated that the antitumor effect was achieved through apoptosis induction and inhibition of DNA synthesis by blocking the G₀/G₁ phase of the cell cycle. In addition, complex 2 showed significant inhibition against B. dysentery with an inhibition circle diameter of 24 mm.

A new bio-active asymmetric-Schiff base: synthesis and evaluation of calf thymus DNA interaction, topoisomerase IIα inhibition, in vitro antiproliferative activity, SEM analysis and molecular docking studies

In this paper, the asymmetric-Schiff base 2-(4-(2-hydroxybenzylideneamino)benzylideneamino)benzoic acid (SB-2) was newly synthesized and characterized by various spectroscopic methods. The interaction of SB-2 with calf thymus DNA was investigated by UV-vis, fluorescence spectroscopy and molecular docking methods. It was determined that SB-2 effectively binds to DNA via the intercalation mode. DNA electrophoretic mobility experiments displayed that topoisomerase IIα could not cleave pBR322 plasmid DNA in the presence of SB-2, confirming that the Schiff base acts as a topo II suppressor. In the molecular docking studies, SB-2 was found to show an affinity for both the DNA-topoisomerase IIα complex and the DNA. In vitro antiproliferative activity of SB-2 was screened against HT-29 (colorectal) and HeLa (cervical) human tumor cell lines by MTT assay. SB-2 diminished the cell viability in a concentration- and incubation time-dependent manner. The ability of SB-2 to measure DNA damage in tumor cells was evaluated with cytokinesis-block micronucleus assay after incubation 24 h and 48 h. Light and scanning electron microscopy experiments of tumor cells demonstrated an incubation time-dependent increase in the proportion of apoptotic cells (nuclear condensation and apoptotic bodies) suggesting that autophagy and apoptosis play a role in the death of cells. Based on the obtained results, it may be considered that SB-2 is a candidate for DNA-targeting antitumor drug.Communicated by Ramaswamy H. Sarma.

Chromone‐Appended Zn(II) tRNA‐Targeted Potential Anticancer Chemotherapeutic Agent: Structural Details, in vitro ct‐DNA/tRNA Binding, Cytotoxicity Studies And Antioxidant Activity

A 3‐formyl‐chromone‐appended zinc(II) intercalator drug candidate of the formulation [bis(chromone)(H 2 O)2 Zn(II)] was prepared as a potent anticancer agent and thoroughly characterized by multi‐spectroscopic and single X‐ray crystallographic studies.   Preliminary binding studies of complex 1 with ct‐DNA/tRNA were carried out employing various complementary biophysical techniques and the corroborative results of these experiments suggested strong binding propensity via  intercalation binding mode towards ct‐DNA/tRNA  therapeutic targets, with higher preference for tRNA as quantified by  binding constant { K b , K and K sv } parameters. The cleavage studies with pBR322 DNA were performed which implied that 1 cleaved the DNA by hydrolytic cleavage pathway which was further validated by T4 religation assay. Moreover, 1  was found to exhibit the tRNA cleavage behavior in a concentration and time‐dependent manner. The cytotoxicity of complex 1 was evaluated against Huh‐7, DU‐145 and the PNT2 cell lines by MTT assay. A dose‐dependent growth inhibition of the Huh‐7 and DU‐145 cells at low micromolar concentrations was observed and in another set of experiments, lipid peroxidation & glutathione (GSH) depletion were induced in the presence of the tested drug candidate. Interestingly, drug candidate 1 demonstrated selective cytotoxic activity for the DU‐145 cancer cell line with LC50 value of 3.2 μM which was further visualized by confocal microscopy.

Copper in tumors and the use of copper-based compounds in cancer treatment

Copper homeostasis is strictly regulated by protein transporters and chaperones, to allow its correct distribution and avoid uncontrolled redox reactions. Several studies address copper as involved in cancer development and spreading (epithelial to mesenchymal transition, angiogenesis). However, being endogenous and displaying a tremendous potential to generate free radicals, copper is a perfect candidate, once opportunely complexed, to be used as a drug in cancer therapy with low adverse effects. Copper ions can be modulated by the organic counterpart, after complexed to their metalcore, either in redox potential or geometry and consequently reactivity. During the last four decades, many copper complexes were studied regarding their reactivity toward cancer cells, and many of them could be a drug choice for phase II and III in cancer therapy. Also, there is promising evidence of using ⁶⁴Cu in nanoparticles as radiopharmaceuticals for both positron emission tomography (PET) imaging and treatment of hypoxic tumors. However, few compounds have gone beyond testing in animal models, and none of them got the status of a drug for cancer chemotherapy. The main challenge is their solubility in physiological buffers and their different and non-predictable mechanism of action. Moreover, it is difficult to rationalize a structure-based activity for drug design and delivery. In this review, we describe the role of copper in cancer, the effects of copper-complexes on tumor cell death mechanisms, and point to the new copper complexes applicable as drugs, suggesting that they may represent at least one component of a multi-action combination in cancer therapy.

Dimeric Drugs

This review intends to summarize the structures of an extensive number of symmetrical-dimeric drugs, having two monomers linked via a bridging entity while emphasizing the large versatility of biologically active substances reported to possess dimeric structures. The largest number of classes of these compounds consist of anticancer agents, antibiotics/antimicrobials, and anti-AIDS drugs. Other symmetrical-dimeric drugs include antidiabetics, antidepressants, analgesics, anti-inflammatories, drugs for the treatment of Alzheimer's disease, anticholesterolemics, estrogenics, antioxidants, enzyme inhibitors, anti-Parkisonians, laxatives, antiallergy compounds, cannabinoids, etc. Most of the articles reviewed do not compare the activity/potency of the dimers to that of their corresponding monomers. Only in limited cases, various suggestions have been made to justify unexpected higher activity of the dimers vs. the corresponding monomers. These suggestions include statistical effects, the presence of dimeric receptors, binding of a dimer to two receptors simultaneously, and others. It is virtually impossible to predict which dimers will be preferable to their respective monomers, or which linking bridges will lead to the most active compounds. It is expected that the extensive number of articles summarized, and the large variety of substances mentioned, which display various biological activities, should be of interest to many academic and industrial medicinal chemists.

Ruthenium complexes show promise when submitted to toxicological safety tests using alternative methodologies

The number of cancer cases continues to increase worldwide, and unfortunately the main systemic treatments available have numerous of side effects. Ruthenium complexes have shown to be promising chemotherapeutic agents, since they present low toxicity and are more selective for tumor tissues. We report the synthesis, characterization and biological properties of two new ruthenium (II) complexes containing Lapachol and Lawsone as ligands: (1) [Ru(Law)(dppb)(phen)]PF₆ and (2) [Ru(Lap)(dppb)(phen)]PF₆, where Law = Lawsone, Lap = Lapachol, dppb = 1,4-bis(diphenylphosphine)butane and phen = 1,10-phenanthroline. The ability of the complexes (1) and (2) to interact with CT-DNA (Calf Thymus) was investigated, and the results indicate that the complexes have shown a weak interaction with this macromolecule. Complexes (1) and (2) showed a moderate interaction with BSA, via a spontaneous process with the involvement of van der Waals and hydrogen bond interactions. Both complexes were tested against human lung cancer cell lines, chronic human myeloid leukemia, murine melanoma and human cervical and non-tumoral murine fibroblast adenocarcinoma, human lung fibroblasts and monkey kidney epithelia. The potential for cytotoxicity was tested out using the MTT assay and the neutral red test, to calculate inhibitory concentrations (IC50) and selectivity indices (IS). Both complexes showed a higher selectivity index of 1.17 and 10.91, respectively, for the HeLa tumor line. Studies of toxicological evaluation, using the micronucleus test and the comet assay against non-tumor cells, as well as an assessment of the potential for acute toxicity and neurotoxicity in zebrafish (Danio rerio). In the in vitro micronucleus test, complex (1) showed the least genotoxic potential, and in the in vitro comet assay both compounds had revealed a genotoxic potential at 0.5 and 1.0 mg L^-1, with no difference between 24 h and 48 h exposure times. In the acute toxicity tests on zebrafish embryos, complex (1) showed sublethal effects such as decreased blood circulation and heartbeat rate, which were less pronounced than with complex (2). In contrast to complex 2, which caused lethality even before 48h, complex (1) did not cause the death of the embryos at concentrations up to (2.0 mg L^-1). Complex (2) also lead to a delay in the embryo. Cell based in vitro methods thus proved able to provide specific toxicological data, allowing a significant reduction in ∖animal experimentation. Given that in vitro tests cannot completely replace animal tests, the use of less advanced developmental stages such as zebrafish embryos, which - at least in the European Union - are not regarded protected, could be shown to be an excellent alternative for testing with, e.g., mammals.

Nitrile-containing copper(ii) porphyrin coordination complexes for efficient anticancer activity and mechanism research

Synthesis and anticancer activity of nitrile-containing copper(ii) porphyrin coordination complexes.

Synthesis and physicochemical, DFT, thermal and DNA-binding analysis of a new pentadentate N3S2 Schiff base ligand and its [CuN3S2]2+ complexes

A new N₃S₂ pentadentate Schiff base ligand derived from 5-bromothiophene-2-carbaldehyde, (E)-N1-((5-bromothiophen-2-yl)methylene)-N2-(2-((E)-((5-bromothiophen-2-yl)-methylene amino) ethyl ethane-1,2-diamine, is prepared. The ligand and its complexes are subjected to extensive physical and theoretical analyses and the results are consistent with their predicted compositions. Dicationic Cu(ii) complexes ([CuN₃S₂]X₂) with a coordination number of 5 are proposed on the basis of the spectral data with N₃S₂ serving as a pentadentate ligand. The prepared complexes display a square pyramidal geometry around the Cu(ii) center. TG shows different thermal behavior for the N₃S₂ ligand and its complexes. Solvatochromism of the complexes is promoted by the polarity of the solvent used. A one-electron transfer Cu(ii)/Cu(i) reversible redox reaction is promoted by CV. SEM and EDS of the free ligand and its complexes support the morphology and composition changes observed upon the complexation of Cu(ii). As an outstanding goal to develop anticancer new metal chemotherapy, preliminary studies of the binding of the desired complexes with DNA were carried out, as it is through judging the strength of interactions that a future drug can be designed and synthesized. The viscosity and absorption results obtained for complex 1 indicated its enhanced CT-DNA binding properties as compared to those of complex 2 with K_b values of 3.2 × 10⁵ and 2.5 × 10⁵ M⁻¹, respectively.

A new N₃S₂ pentadentate Schiff base ligand derived from 5-bromothiophene-2-carbaldehyde, (E)-N1-((5-bromothiophen-2-yl)methylene)-N2-(2-((E)-((5-bromothiophen-2-yl)-methylene amino) ethyl ethane-1,2-diamine, is prepared.