Cleavage Process Research Articles

Unveiling the role of aniline as a Brønsted base in Rh-catalyzed C−H alkylation: Computational insights into amino-assisted outer-sphere CMD

C−H bond cleavage is a key step for the formation of new C−Rh bond in Rh-catalyzed alkylation of aniline derivatives. Due to the inherent basicity of aniline, there is ongoing debate regarding its ability to act as a Brønsted base to assist C−H bond cleavage in these type reactions. In this report, we present computational evidence supporting an amino-assisted outer-sphere concerted metalation-deprotonation (CMD) mechanism. Here, the aniline acts as a Brønsted base to facilitate C−H bond cleavage without any direct interaction between the Rh and the aniline. This amino-assisted outer-sphere CMD pathway is found to be lower in energy compared with the inner-sphere CMD and other base-assisted C−H bond cleavage pathways, providing new insights into the mechanism of Rh-catalyzed C−H functionalization of aniline derivatives. Geometric analysis was conducted to elucidate details of the C−H bond cleavage process. This mechanistic study of C−H bond cleavage in Rh-catalyzed oxidative C−H alkylation of aniline derivatives with allyl alcohols is an important case study of the involvement of amino-assisted outer-sphere CMD in Rh catalysis. We anticipate that the novel amino-assisted outer-sphere CMD mode may extend to other C−H bond functionalization processes and explain the unique effectiveness of aniline in many instances.

CRISPR/Cas9-Mediated BocPDSs Gene Editing in Chinese Kale Using the Endogenous tRNA-Processing System

Chinese kale is a native vegetable from the Brassicaceae family that is grown extensively in Southeast Asia and Southern China. Its low genetic transformation and gene editing efficiency hinder gene function research and molecular biology in Chinese kale. CRISPR/Cas9 is a useful tool for plant genome research due to its rapid development and optimization. This study targeted BocPDSs, (BocPDS1, BocPDS2) to establish an effective CRISPR/Cas9 system in Chinese kale. A tandemly arranged tRNA-sgRNA construct was used to express numerous sgRNAs to induce BocPDS1 and BocPDS2 double and single mutations, with a mutation rate of 61.11%. As predicted, several mutant plants showed an albino phenotype with a harbored mutation in an exon and intron region, highlighting the relevance of the intron. The presence of mutations in the intron region suggests that the cleavage process in Chinese kale, utilizing CRISPR/Cas9 shows a preference for AT-rich regions. The distinct and somewhat redundant functions of BocPDS1 and BocPDS2 are demonstrated by the complete albino phenotype of the double mutants and the mosaic albino phenotype of the individual BocPDS1 and BocPDS2 mutants. Specific gene editing modes, including base deletion, base substitution, and base insertion, were identified in the sequence of the target gene. Among them, short nucleotide insertions were the most common type of insertion, with base insertions having the highest frequency (61.54%). Furthermore, no instances of off-target gene editing were detected. The current work demonstrated that the CRISPR/Cas9 gene editing system, which relies on endogenous tRNA processing, can effectively induce mutagenesis in Chinese kale. This finding establishes a theoretical basis and technical backbone for the more effective implementation of CRISPR/Cas9 gene-editing technology in Chinese kale and Brassica plants.

Morphology and chronology of critical events for early‐life history survival of an old word killifish, Esmaeilius shirini (Teleostei: Aphaniidae): A conservation management approach

AbstractIn this study, the live cell imaging microscopy of an old word cyprinodontiform fish, the Shirini toothcarp Esmaeilius shirini during its embryogenesis, is described and illustrated for the first time through the detailed morphological description and chronology of the events of all developmental stages (from fertilization to hatching). External fertilization of transparent, spherical, sticky and macrolecithal eggs bearing adhesive filaments with an average diameter of 0.83–1 mm is the first step in the ontogenesis of E. shirini. Embryogenesis continued with a process of meroblastic cleavage (approximately 2 and half h post‐fertilization, hpf), formation of blastula (blastulation), gastrula (gastrulation), neurulation, somatogenesis, organ formation (organogenesis) and pre‐hatching. The development continued with hatching (a stage between the embryonic and larval periods) at approximately 131 haf (at 24 ± 1°C). The new larvae were about 3.9–5.8 mm in length with distinct fin rays and pigmentation on the head, body and fins. Basic data from this study can be used in forthcoming investigations on the reproduction processes, breeding, behaviour and conservation of E. shirini. Fish development comprises an integrated, ordered and well‐mapped sequence of early life‐history events controlled by intrinsic and extrinsic factors. Knowledge of fish developmental stages during embryogenesis/ontogeny is essential for a better understanding of their biology, breeding criteria, phylogenetic relationships, dietary requirements, conservation plans, environmental requirements and ecological preferences.

Synergistic Palladium/Silver/Ligand Catalysis for C−H Alkenylation of 2,1,3‐Benzofused Heterodiazoles

AbstractThe combination of palladium and silver complexes has emerged as a bimetallic catalytic system in C−H activation, frequently outperforming palladium‐only systems. Beyond the conventional roles of silver (I) salts serving as oxidants, halide scavengers, and Lewis acids, Pd−Ag bimetallic synergism has been shown to facilitate C−H cleavage. In this study, we explore the incorporation of a pyrazolopyridone (PzPyOH) ligand into a Pd−Ag bimetallic catalytic system, which together promote both C−H cleavage and migratory insertion processes. This synergistic approach enables dehydrogenative C−H alkenylations at the C4 position of 2,1,3‐benzothiadiazole, 2,1,3‐benzoxadiazole, and 2,1,3‐benzotriazole with alkenes. These results demonstrate the potential of combining novel ligands with heterobimetallic systems to facilitate other elementary steps beyond C−H cleavage, suggesting their broader applicability in C−H functionalization.

Exploring the Photocatalytic Cleavage Pathway of the β-5 Linkage Lignin Model Compound on Carbon Nitride.

As a globally abundant source of biomass, lignocellulosic biomass has been the centre of attention as a potential resource for green energy generation and value-added chemical production. A key component of lignocellulosic biomass, lignin, which is comprised of aromatic monomers, is a potential feedstock for value added chemical production. The cleavage processes of the linkages between monomers to obtain high value products, however, requires significant investigation as it is a complex, non-facile process. This study focuses on the photocatalytic valorization of a β-5 lignin model compound, a key linkage in the lignin structure. It was found that greater yields of aromatic products were obtained from the photocatalytic conversion of β-5 lignin model compound using carbon nitride (CN) when compared to Evonik P25 titanium dioxide (TiO2). Products of the β-5 model compound photocatalytic conversion were determined and C-C bond cleavage was observed. It was also determined that the solvent participated in the reactions with the introduction of a cyano group to one of the products. Radical quenching experiments revealed that superoxide radicals participated in the CN photocatalytic conversion. These results reveal for the first time the products and possible mechanism of the photocatalytic transformation of β-5 model compounds using CN photocatalysis.

Heteropolyacids promoted NiMo/MOF catalyst for catalytic oxidation of lignin dimers in oxygen atmosphere

Lignin, as an important biomass resource, has significant research value in its oxidative cleavage process. Nickel-based metal catalysts could selectively depolymerize lignin. A series of heteropolyacid doped nickel based bimetallic catalysts Ni4Mo1-MOF-x（x represented heteropolyacid）were prepared by hydrothermal method, which were calcined to catalyze the oxidative cleavage of lignin model compound (2-phenoxy-1-acetophenone). The catalyst Ni4Mo1-MOF-SiWA-0.1(500) showed the best catalytic performance in methanol solvent under conditions of 160 °C, 4 h, 0.5 MPa oxygen pressure, where the conversion rate was nearly 100 % and the yields of phenol and benzoic acid were 54.5 % and 23.3 %, respectively. The catalysts were well characterized to explore the catalytic performance during the oxidation of lignin dimer. This study could provide some interesting and useful information for the catalytic oxidation of lignin to biomass-derived chemicals.

Difluorocarbene Generation via a Spin-Forbidden Excitation under Visible Light Irradiation.

The generation of difluorocarbene from difluoromethane bis(sulfonium ylide) 1 through spin-forbidden excitation under irradiation with 450 nm blue light was reported. The formation of difluorocarbene was confirmed by its reaction with styrene derivatives for the generation of difluorocyclopropanation and insertion into RX-H bonds (X = O, S) for the generation of RXCF2H. The spin-forbidden excitation mechanism for the formation of difluorocarbene from difluoromethane bis(sulfonium ylide) was supported by spectroscopic and kinetic studies as well as computational chemistry. The homolytic cleavage of two S-C bonds in compound 1 under irradiation was confirmed by time-resolved EPR spectroscopic studies of the precursor's free-radical-capturing reaction, as well as the isolation of the dimer of dimethyl (phenylthiol)malonyl radical. Further studies showed that the homolytic cleavage process occurred asynchronously in the solvent cage based on the isotope-labeled scrambling experiments and DFT calculations.

Visible light-driven selective oxidative transformation of vicinal diols using ZnS-based photocatalyst in the presence of molecular oxygen

The heterogeneous photocatalysis for the oxidative cleavage of C–C bond is significant to the transformation of biomass feedstock. In this work, a heterojunction photocatalyst based on the conductor ZnS and C3N4 (CN) material is prepared and employed in the aerobic oxidative cleavage reaction of vicinal diol under visible light irradiation. As a result, it is found that 3ZnS/CN catalyst obtained by a mechanical grinding method shows a high photocatalytic activity. In the photocatalytic oxidative cleavage process of 1-phenyl-1,2-glycol, more than 98.7% conversion of substrate with a 96.2% selectivity of benzaldehyde was attained using O2 as oxidant. In addition, the photocatalyst recycling experiments exhibited that the 3ZnS/CN catalyst still kept a good activity and stability even after being recycled for 5 times. Finally, the active reaction intermediates were investigated by the control experiments and the relative electron paramagnetic resonance (EPR) detection. According to the obtained results and photocatalytic principle, the mechanism for the selective oxidative transformatioin of 1-phenyl-1,2-glycol has been proposed. It gives a promising approach for the catalytic utilization of biomass-based lignin and cellulose.

Mechanistic studies on phosphine-catalyzed [4 + 3] annulation of β′-acetoxy allenoate with 1C,3N-dinucleophile

The mechanism and role of catalyst on the PPh3-catalyzed [4 + 3] annulation reaction have been systematically investigated using density functional theory (DFT) method. Based on the calculations, the possible mechanism contains six steps: nucleophilic addition of PPh3 to allenoate to give Z-configured intermediate, cleavage of CO bond for forming phosphonium diene, nucleophilic addition of phosphonium diene with anionic 1C,3N-dinucleophile, intramolecular [1,5]-proton shift, ring-closure, and dissociation of catalyst. Non-covalent interaction (NCI) analysis shows that the O⋯P interaction would be the key for leading to the Z-configured pathway more favorable and electron localization function (ELF) analysis indicates that the implication of PPh3 can significantly lower the energy barrier involved in CO cleavage process, which mainly because the addition of PPh3 reduces the electron density of CO bond and thus facilities the cleavage of CO bond. This theoretical study would provide some clues for understanding the role of catalyst in a catalytic reaction.

Determinants of selectivity in the dicing mechanism

Our research elucidates the cleavage processes of the RNase III enzyme, DICER, which plays a crucial role in the production of small RNAs, such as microRNAs (miRNAs) and small interfering RNAs (siRNAs). Utilizing high-throughput dicing assays, we expose the bipartite pairing rule that dictates the cleavage sites of DICER. Furthermore, we decode the intricate recognition mechanism of the primary YCR motif and identify an analogous secondary YCR motif that influences DICER's cleavage choices. Collectively, our findings clarify the bipartite pairing rule and enhance our understanding of the role of RNA motifs in modulating DICER's cleavage activity, laying the groundwork for future research on their roles in miRNA biogenesis and gene regulation.

Photoinduced Radical Approach for Desulfurative Alkylation of Cysteine Derivatives to Make Unnatural Amino Acids.

Unnatural amino acids (UAAs) are highly valuable molecules in organic synthesis, pharmaceutical sciences, and material science. Herein, we present a photocatalytic radical approach for desulfurative alkylation of cysteine derivatives with arenethiol as the hydrogen atom transfer catalyst for making UAAs and peptides. The formate salt, acting as the hydrogen atom donor, in situ generates the highly reductive CO2 radical anion species, which is the key to unlocking the C-S bond cleavage process with a simple benzoyl protecting group. No photocatalyst is required for the radical initiation and propagation, which makes such a visible-light-induced process mild, efficient, and sustainable.

Proximity ligation-triggered DNAzyme for selective fluorescent aptasensing of methicillin-resistant Staphylococcus aureus

There is an urgent need for novel strategies to accurately and reliably detect pathogenic bacteria to address the global epidemic of antibiotic resistance. This study proposes an innovative approach combining dual aptamer-based target recognition and proximity ligation assay (PLA) triggered DNAzyme recycling cleavage. This method allows for the precise identification and reliable detection of methicillin-resistant Staphylococcus aureus (MRSA). The fluorescence probe labeled with a fluorophore is modified on gold nanoparticles (AuNPs), resulting in the quenching of the fluorescent signal by the AuNPs. The interaction between MRSA and two aptamers leads to forming a Mg2+-dependent DNAzyme. The DNAzyme cleaves the fluorescence probe, causing the fluorescent fragment to detach from the surface of the AuNPs, in which the quenched fluorescence signal in the fluorescence probe reappears. The DNAzyme-assisted cleavage and rebinding process generates a processive strolling along the surface track of AuNPs. Consequently, the fluorescence intensity experiences a substantial recovery. A strong linear correlation is observed between the fluorescence intensity and MRSA concentration within 50 cfu/mL to 106 cfu/mL. We believe that implementing the novel integrated strategy will broaden the range of bacterial detection methods in the battlefield environment and stimulate the creation of potential new drugs in the future.

Nitrate Enhanced Sulfamethoxazole Degradation by 222 nm Far-UVC Irradiation: Role of Reactive Nitrogen Species.

The application of 222 nm far-UVC irradiation for degrading organic micropollutants in water shows promise. Nitrate (NO3-), found in nearly all water bodies, can significantly impact the performance of 222 nm far-UVC-driven systems. This work was the first to investigate the effect of NO3- on sulfamethoxazole (SMX) photodegradation at 222 nm, finding that NO3- significantly enhances SMX degradation in different dissociated forms. Besides the hydroxyl radical (•OH), reactive nitrogen species (RNS) also played important roles in SMX degradation. With increasing NO3- concentration, the RNS contribution to SMX degradation decreased from 25.7 to 8.6% at pH 3 but increased from 1.5 to 24.7% at pH 7, since the deprotonated SMX with electron-rich groups reacted more easily with RNS. The transformation mechanisms of SMX involving isomerization, bond cleavage, hydroxylation, nitrosation, and nitration processes were proposed. 15N isotope labeling experiments showed that the RNS-induced nitrated products even became the major products of SMX in the 222 nm far-UVC/NO3- system at pH 7 and exhibited a higher toxicity than SMX itself. Further research is necessary to avoid or eliminate these toxic byproducts. This study provides valuable insights for guiding the utilization of 222 nm far-UVC for treating antibiotics in NO3--containing water.

Full-Length Transcriptome Profiling of the Complete Mitochondrial Genome of Sericothrips houjii (Thysanoptera: Thripidae: Sericothripinae) Featuring Extensive Gene Rearrangement and Duplicated Control Regions.

The mitochondrial genome (mitogenome) of Thysanoptera has extensive gene rearrangement, and some species have repeatable control regions. To investigate the characteristics of the gene expression, transcription and post-transcriptional processes in such extensively gene-rearranged mitogenomes, we sequenced the mitogenome and mitochondrial transcriptome of Sericothrips houjii to analyze. The mitogenome was 14,965 bp in length and included two CRs contains 140 bp repeats between COIII-trnN (CR1) and trnT-trnP (CR2). Unlike the putative ancestral arrangement of insects, S. houjii exhibited only six conserved gene blocks encompassing 14 genes (trnL2-COII, trnD-trnK, ND2-trnW, ATP8-ATP6, ND5-trnH-ND4-ND4L and trnV-lrRNA). A quantitative transcription map showed the gene with the highest relative expression in the mitogenome was ND4-ND4L. Based on analyses of polycistronic transcripts, non-coding RNAs (ncRNAs) and antisense transcripts, we proposed a transcriptional model of this mitogenome. Both CRs contained the transcription initiation sites (TISs) and transcription termination sites (TTSs) of both strands, and an additional TIS for the majority strand (J-strand) was found within antisense lrRNA. The post-transcriptional cleavage processes followed the "tRNA punctuation" model. After the cleavage of transfer RNAs (tRNAs), COI and ND3 matured as bicistronic mRNA COI/ND3 due to the translocation of intervening tRNAs, and the 3' untranslated region (UTR) remained in the mRNAs for COII, COIII, CYTB and ND5. Additionally, isoform RNAs of ND2, srRNA and lrRNA were identified. In summary, the relative mitochondrial gene expression levels, transcriptional model and post-transcriptional cleavage process of S. houjii are notably different from those insects with typical mitochondrial gene arrangements. In addition, the phylogenetic tree of Thripidae including S. houjii was reconstructed. Our study provides insights into the phylogenetic status of Sericothripinae and the transcriptional and post-transcriptional regulation processes of extensively gene-rearranged insect mitogenomes.

Synthesis of 2‐Aminopyridine Derivatives via a Tandem CuAAC/Ring‐Cleavage/[4+2]‐Cycloaddition/Rearrangement Reaction Sequence

Abstract2H‐Azirines are an important class of small‐ring heterocycle that have been employed as versatile synthetic building blocks. Herein, a one‐pot CuAAC/ring‐cleavage/[4+2]‐cycloaddition/rearrangement reaction sequence involving terminal ynones, sulfonyl azides and 2H‐azirines is reported that leads to 2‐aminopyridine derivatives. In the first step, highly reactive N‐sulfonyl α‐acylketenimines are generated, via a CuAAC/ring‐cleavage process, from sulfonyl azides and terminal ynones and these undergo inverse electron‐demand Diels–Alder cycloaddition reactions with 2H‐azirines to form (isolable) 1,3‐oxazines that themselves undergo base‐promoted ring‐cleavage and rearrangement reactions to afford the title compounds.

Cas1 mediates the interference stage in a phage-encoded CRISPR-Cas system.

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems are prokaryotic adaptive immune systems against invading phages and other mobile genetic elements. Notably, some phages, including the Vibrio cholerae-infecting ICP1 (International Center for Diarrheal Disease Research, Bangladesh cholera phage 1), harbor CRISPR-Cas systems to counteract host defenses. Nevertheless, ICP1 Cas8f lacks the helical bundle domain essential for recruitment of helicase-nuclease Cas2/3 during target DNA cleavage and how this system accomplishes the interference stage remains unknown. Here, we found that Cas1, a highly conserved component known to exclusively work in the adaptation stage, also mediates the interference stage through connecting Cas2/3 to the DNA-bound CRISPR-associated complex for antiviral defense (Cascade; CRISPR system yersinia, Csy) of the ICP1 CRISPR-Cas system. A series of structures of Csy, Csy-dsDNA (double-stranded DNA), Cas1-Cas2/3 and Csy-dsDNA-Cas1-Cas2/3 complexes reveal the whole process of Cas1-mediated target DNA cleavage by the ICP1 CRISPR-Cas system. Together, these data support an unprecedented model in which Cas1 mediates the interference stage in a phage-encoded CRISPR-Cas system and the study also sheds light on a unique model of primed adaptation.

Scalable preparation of green C-terminal amidation peptide-synthesis TAGs and the optimized TAG-assisted liquid-phase synthesis of eptifibatide

Eptifibatide is a cycloheptapeptide with C-terminal amidation and head-to-tail disulfide bridging, which has been approved as an antithrombotic drug. Currently, both at the laboratory scale and industrial level, the synthesis of eptifibatide predominantly relies on solid-phase peptide synthesis (SPPS), which is not regarded as a green sustainable and cost-effective approach to prepare eptifibatide. Herein, we have investigated the strategy employing tag-assisted liquid-phase peptide synthesis (TAG-Assisted LPPS) technology that is scalable to multi-gram scale manufacturing for eptifibatide preparation. We successfully obtained soluble Rink-Amide TAGs by esterifying organophosphorus TAG-OH with Rink-Amide, thereby facilitating the transition from synthesizing C-terminal carboxyl peptides to C-terminal amidation peptides. The products obtained during the tag-assisted coupling and Fmoc deprotection of eptifibatide intermediates can be purified through precipitation processes, eliminating the need for complex chromatographic operations. Accordingly, we developed an optimized laboratory-scale process (300 mmol) for the preparation of TAG-Rink Amide TAG, which was subsequently upscaled successfully to a 50 mmol batch synthesis of eptifibatide. The subsequent work also explores the processes of peptide cleavage and disulfide bond oxidative cyclization in eptifibatide preparation.

Elimination of representative antibiotic-resistant bacteria, antibiotic resistance genes and ciprofloxacin from water via photoactivation of periodate using FeS2

The propagation of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) induced by the release of antibiotics poses great threats to ecological safety and human health. In this study, periodate (PI)/FeS2/simulated sunlight (SSL) system was employed to remove representative ARB, ARGs and antibiotics in water. 1 × 107 CFU mL–1 of gentamycin-resistant Escherichia coli was effectively disinfected below limit of detection in PI/FeS2/SSL system under different water matrix and in real water samples. Sulfadiazine-resistant Pseudomonas and Gram-positive Bacillus subtilis could also be efficiently sterilized. Theoretical calculation showed that (110) facet was the most reactive facet on FeS2 to activate PI for the generation of reactive species (·OH, ·O2–, h+ and Fe(IV)=O) to damage cell membrane and intracellular enzyme defense system. Both intracellular and extracellular ARGs could be degraded and the expression levels of multidrug resistance-related genes were downregulated during the disinfection process. Thus, horizontal gene transfer (HGT) of ARB was inhibited. Moreover, PI/FeS2/SSL system could disinfect ARB in a continuous flow reactor and in an enlarged reactor under natural sunlight irradiation. PI/FeS2/SSL system could also effectively degrade the HGT-promoting antibiotic (ciprofloxacin) via hydroxylation and ring cleavage process. Overall, PI/FeS2/SSL exhibited great promise for the elimination of antibiotic resistance from water.

Simultaneous inactivation of Microcystis aeruginosa and degradation of microcystin-LR in water by activation of periodate with sunlight

Harmful algal blooms pose tremendous threats to ecological safety and human health. In this study, simulated solar light (SSL) irradiation was used to activate periodate (PI) for the inactivation of Microcystis aeruginosa and degradation of microcystin-LR (MC-LR). We found that PI-SSL system could effectively inactivate 5 × 106 cells·mL−1 algal cells below the limit of detection within 180 min. ·OH and iodine (IO3· and IO4·) radicals generated in PI-SSL system could rupture cell membranes, releasing intracellular substances including MC-LR into the reaction system. However, the released MC-LR could be degraded into non-toxic small molecules via hydroxylation and ring cleavage processes in PI-SSL system, reducing their environmental risks. High algae inactivation performance of PI-SSL system in solution with a wide pH range (3–9), with the coexisting anions (Cl−, NO3− and SO42−) and the copresence of natural organic matters (humic acid and fulvic acid), real water (lake water and river water), as well as in continuous-flow reactor (14 h) were also achieved. In addition, under natural sunlight irradiation, effective algae inactivation could also be achieved in an enlarged reactor (1 L). Overall, our study showed that PI-SSL system could avoid the inference by the background substances and could be employed as a feasible technique to treat algal bloom water.

De novo design and preparation, structural details, and cytotoxic response of a new water soluble (2,2′–bipy)–(phenylalaninato)–μ–chlorido–copper(II) drug candidate against resistant cancer cells

A new water soluble (2,2′–bipyridine)–(phenylalaninato)–μ–chlorido–copper(II) complex was synthesized using ancillary ligands, l-phenylalanine, and 2,2-bipyridine as a chemotherapeutic anticancer agent. The complex was characterized by employing various spectroscopic (UV–visible, FT-IR, EPR, elemental analysis) and single crystal X-ray diffraction technique which revealed the structure of crystal as monoclinic with P21 space group. The interaction studies of the complex with therapeutic drug target, ct-DNA were caried out using various complimentary biophysical techniques, and the corroborative results of these experiments revealed that complex binds avidly through non-covalent electrostatic binding mode in the groove region of DNA. The binding propensity was quantified by calculating the intrinsic binding constant values (Kb and Ksv) which were found to be 3.1 (±0.95) × 105M−1 and 0.4 (±0.05) × 103M−1, respectively. The cleavage studies of copper(II) based drug candidate 1 with pBR322 plasmid DNA were performed in concentration dependent manner and it was demonstrated that complex was capable of conversion of supercoiled form SC (Form I) into nicked form NC (Form II) upon incubation of 3 μM concentration, implicating efficient single strand cleavage of DNA helix. The mechanistic cleavage studies were also performed in the presence various activators viz., DMSO, NaN3, SOD, and H2O2 and the strong inhibition of cleavage process was observed in presence of NaN3 and SOD that suggested an oxidative pathway (Fenton's mechanism) for the Cu(II) complex. The cytotoxicity of the complex was evaluated by SRB assay against the resistant cancer cell lines, viz., Hop-62, MCF-7, AW13516, MDA-MB-231, and SiHa. The cytotoxicity activity demonstrated good therapeutic potency against all the tested cell lines with GI50 value of <10 μM.