Oxygen Of Carbonyl Group Research Articles

Synthesis, characterization, molecular modeling, and antimicrobial study of copper(II) 2-chlorophenylacetohydroxamate

A copper(II) 2-chlorophenylacetohydroxamate complex has been synthesized using copper(II) chloride and potassium 2-chlorophenylacetohydroxamate in 1:2 molar ratio in methanol and characterized using CHN analysis, IR, 1H NMR, 13C NMR spectroscopy, and mass spectrometry. The hydroxamate ligand binds to metal via oxygen of carbonyl group and hydroxamic group (O, O bonding), and a distorted-square planar geometry has tentatively been proposed. The interactions between Staphylococcus aureus (bacterial receptor) ligand and complex, their inhibition constant, and binding energy values have been computed. The in vitro antimicrobial activity study against pathogenic gram –ve bacteria viz. Salmonella typhi and Escherichia coli; gram + ve S. aureus and Bacillus cereus by MIC method have revealed a significant antimicrobial potential.

Synergistic anti-fungal action of azole compounds with mixed ligand complexes and their applications

Selenium (Se (II)) and Zinc (Zn (II)) mixed ligand complexes containing glycine (gly) and pyroglutamic acid (l-PCA) as primary ligands, and salicylic acid (HL1) and glycolic acid (HL2) as secondary ligands have been prepared. These novel complexes were characterized using elemental analysis, 1H NMR, 13CNMR, UV–Vis., FTIR, X-ray diffraction, mass spectra and thermal analysis. The elemental analysis revealed the formation of [1:1:1] zinc or selenium amino acid-hydroxy acid complexes.The bonds interactions between Se (II), Zn (II), and ligands had been investigated using IR spectrophotometry revealing that the ligands exhibited neutral bidentate behavior; the amino acid (primary ligand) coordinates through the nitrogen atom and the carbonyl group's oxygen atom, whereas the hydroxy acids HL1 and HL2 (secondary ligands) coordinate through the OH group and the carbonyl group's oxygen atom.Electronic absorption spectra of the mixed-ligand complexes indicate a square planar shape. The prepared mixed ligand complexes were encapsulated with another powerful antifungal agent, climbazole, in nanostructured lipid carriers (NLCs) for topical application to improve the therapeutic activity. The NLCs were prepared by a hot homogenization method and characterized by particle size, drug entrapment, in vitro drug release, and zeta potential to guarantee the stability of the desired nanostructured lipid carriers (NLCs). The microbiological activity of climbazole-mixed ligand complexes and their encapsulated forms were assessed against Malassezia furfur, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Escherichia coli. In comparison to Se (II) and Zn (II) mixed ligand complexes alone, the study revealed that the combination of Se (II) and Zn (II) mixed ligand complexes with climbazole in NLCs considerably increased antibacterial activity against the tested microbial strains. P ≤ 0.05 indicates statistical significance for the difference.

Transition metal complexes of N'-(2-cyanoacetyl)nicotinohydrazide: Synthesis, structural and anticancer activity studies

On reacting the nicotinic hydrazide with 1-cyanoacetyl-3,5-dimethylpyrazole, a new ligand, N'-(2-cyanoacetyl)nicotinohydrazide (H2L), was produced and characterized using diverse spectral studies which cleared out that the free ligand existed in keto form. The ligand reacted with Cu(II), Co(II), Ni(II) and Zn(II) acetates affording metal complexes with 1:1 (M:L) stoichiometric which was validated using the elemental and mass spectral measurements. The spectral studies of the isolated complexes showed that the ligand chelated to metal ion in mononegative bidentate fashion via the amide nitrogen and deprotonated enolized carbonyl oxygen group. Moreover, the DFT quantum chemical calculations indicated that the ligand has the highest HOMO-LUMO energy gap, ΔEH-L, while the Co(II) complex has the lowest and may be sorted as H2L > Zn(II) > Cu(II) > Ni(II) > Co(II). Furthermore, isolated compounds’ in vitro cytotoxic activity against HePG-2 and HCT-116 cell lines was investigated and the data cleared that the ligand has very strong, IC50 6.59 ± 0.4 and 8.17 ± 0.7 μM, respectively. Whereas, the metal complexes exhibited moderate to weak potent effect against both cell lines.

Spectroscopic Characterization, Quantum Chemical and Molecular Docking Studies on 1-Chloroanthraquinone: A Novel Oral Squamous Cell Carcinoma Drug

Anthraquinone derivatives are well recognized for their anticancer activities and pharmacological properties. In the present study, comprehensive theoretical and experimental FT-IR, FT-Raman, and UV-visible spectroscopic studies on the 1-Chloroanthraquinone (CAQ) molecule were carried out. The optimized molecular structure and harmonic vibrational frequencies was calculated using Gaussian 09 program. The experimental and calculated vibrational wavenumbers were assigned, which correlated well with the previous literature. The UV-visible absorption spectrum of the CAQ molecule was computed in the liquid phase (ethanol), which exhibits n–π* electronic transition, and the results were compared with the observed UV-visible spectrum. From the frontier molecular orbital analysis, the calculated energy gap value (4.03 eV) indicates that the CAQ molecule has a stable structure and the value was comparable with the band gap energy value of the reported bioactive molecules. The electron back donation from the carbonyl group oxygen atom to the benzene ring was identified using Mulliken atomic charge distribution analysis. Molecular electrostatic potential surface analysis confirms the reactive sites of the molecule. The natural bond orbital analysis validates electron back donation from the carbonyl group oxygen atom to the benzene ring of the CAQ molecule. The molecular docking analysis results that the CAQ molecule acts as a good inhibitor of histone deacetylase 6 (HDAC6) protein. HDAC6 protein is associated with oral squamous cell carcinoma. Thus, the present study paves the way for designing novel drugs for the treatment of oral squamous cell carcinoma.

Exploring the Interaction Between the Newly Designed Antitumor Zn(II) Complex and CT-DNA/BSA: Spectroscopic Methods, DFT Computational Analysis, and Docking Simulation.

A new zinc(II) complex formulated as [Zn(pipr-ac)2], where pipr-ac stands for piperidineacetate, was synthesized and structurally identified with the help of experimental and DFT methods. Frontier molecular orbital (FMO) analysis demonstrated that the new complex has higher biological activity compared to the free ligand. Molecular electrostatic potential (MEP) showed the nitrogen atoms and oxygen of carbonyl groups are the active sites of Zn(II) compound. Also, natural bond orbital (NBO) analysis confirmed the charge transfer from the ligating atoms to the metal ion and formation of four coordinated Zn(II) complex. MTT assay illustrated a noticeable cytotoxic activity of the new zinc(II) complex compared to cisplatin on K562 cell line. The CT-DNA and serum albumin (SA) binding of the Zn(II) complex were explored individually. In this regard, UV-Vis spectroscopy and florescence titration revealed the occurrences of fluorescence quenching of CT-DNA/SA by metal compound via static mechanism and creation of hydrogen bonds and van der Waals interactions between them. The binding was further confirmed by viscosity measurement and gel electrophoresis assay for CT-DNA and circular dichroism spectroscopy for SA. Moreover, molecular docking simulation demonstrated that the new compound binds mainly through hydrogen bonds to the groove of DNA and hydrogen bonds and van der Waals interactions to site I of SA.

Interactions between zein and anthocyanins at different pH: Structural characterization, binding mechanism and stability

Zein-anthocyanin nanoparticles (ZACNPs) at different pH values were successfully developed to stabilize anthocyanins based on the self-assembly properties of zein. The structural characterization by the Fourier infrared spectroscopy, fluorescence spectroscopy, differential scanning calorimetry and molecular docking analysis showed that the interactions between anthocyanins and zein were driven by the hydrogen bonds formed between the hydroxyl and carbonyl oxygen groups on anthocyanin glycoside groups and the amino acid residues (glutamine and serine), as well as the hydrophobic interactions from the A or B ring of anthocyanins and the amino acid residues of zein. The binding energy of zein to two anthocyanin monomers cyanidin 3-O-glucoside and delphinidin 3-O-glucoside was 8.2 and 7.4 kcal/mol. Further property examinations of ZACNPs showed that the thermal stability of anthocyanins at a ratio of zein:ACN = 1:0.3 was improved by 56.64 % (90 °C, 2 h), and the storage stability increased by up to 31.11 % at pH 2. In addition, the antioxidant activity of ZACNPs (zein:ACN = 1:0.3) was significantly enhanced, and the DPPH, ABTS radical scavenging activities, FRAP and ORAC value reached 87.73 %, 87.89 %, 435.5 μg/mL, 90.58 μmol/mL at pH 4, respectively. These results suggested that combining zein to anthocyanins is a feasible method to stabilize anthocyanins.

Solvatochromism and solution π-stacking of N-(4-pyridyl)-1,8-naphthalimide and its corresponding triruthenium coordination complex

Due to the scarcity of spectroscopic studies on metal-coordinated naphthalimides, and aiming to investigate fundamental spectroscopic aspects, we have described here the aggregates of N-(4-pyridyl)-1,8-naphthalimide (NI-py) in solution as well as solvatochromism displayed by it and by the coordination compounds [Ru3O(CH3COO)6(NI-py)3]n, n = +1 or 0. Based both on theoretical calculations and luminescence spectra, we demonstrated that in aqueous media, the NI-py π-stacking is thermodynamically favored, suggesting a preferable conformation where the pyridine and naphthalene moieties of two NI-py molecules are parallel to each other, but are not co-planar within an individual molecule, due to steric hindrance. The NI-py ππ* band displayed positive solvatochromism, to which the major contribution was the Catalan’s SP parameter (solvent polarizability). This observation is fully consistent with the extended π-electron cloud of the NI-py naphthalene ring. However, a secondary contribution of the SA (solvent acidity) was also observed, owing to the electron pairs available at the N-heteroatom of the pyridine rings and at the carbonyl-group oxygen atoms. Finally, the multiparametric solvent effect analysis indicated that the electronic coupling between coordinated NI-py and the metallic core is modulated by the charge of the [Ru3O(CH3COO)6] core, being higher for the reduced species [Ru3O(CH3COO)6(NI-py)]0. In addition, in this reduced species, there is no overlap between NI-py ππ* and the [Ru3O(CH3COO)6] charge transfer (CT) transitions, leading to the observation of the dependence of the CT energy with the SdP parameter (solvent dipolarity) since the CT transition implies in a charge-separation state.

Enhancing the Performance of Perovskite Solar Cells by 4‐Chloro‐1,8‐Naphthalic Anhydride for Surface Passivation

AbstractOn the surface and grain boundary of perovskite films there are large quantities defects, which leads to photogenerated carrier nonradiative recombination and degrades the performance of the perovskite solar cells (PSCs). Surface passivation can suppress the detrimental effects of defect and improve the performance of PSCs. Here, an organic molecule, 4‐chloro‐1,8‐naphthalic anhydride (ALS), is adopted to passivate the defects on the surface and grain boundary of (FAPbI3)0.95(MAPbBr3)0.05 perovskite films. The oxygen of carbonyl group in the ALS provides lone pair electron to the undercoordinated Pb2+ and passivated this defect. The ALS passivated perovskite films have lower trap state density and longer carrier lifetime. As a result, the photoelectric conversion efficiency (PCE) of the PSCs was improved from 21.52% to 23.72%. Furthermore, the ALS passivated PSC show good stability, and it could maintain 88% of its initial efficiency after 1200 h storage in ambient atmosphere without encapsulation.

Bioremediation pretreatment of waste-activated sludge using microalgae Spirulina platensis derived biochar coupled with sodium sulfite: Performance and microbial community dynamics

4-Nonylphenol is a typical endocrine-disrupting compound found in waste-activated sludge. This study evaluates the feasibility of blue-green algae (Spirulina platensis)-based biochar as a carbon-neutral material to improve sodium sulfite (S(IV))-mediated sludge purification. Blue-green algae-based biochar is an effective activator (at 500 °C and 3 × 10−6 M) of sodium sulfite and removed 75 % of 4-nonylphenol at pH 6 using at 1.7 g/L of dosage. Possible synergistic relationships among the coexisting oxidizing species (SO3•−, SO4•−, HO•, and 1O2), obvious defect structure, and abundant carbonyl oxygen groups on the surface of the biochar together dived advanced oxidation process. The bacterial consortia promoted the decomposition of biologically available substrates in the biosolid mixture, which led to the enrichment of Denitratisoma, and boosted 4-nonylphenol biodegradation. This study outlines a potential carbon–neutral, cost-effective, and sustainable sludge treatment strategy using renewable blue-green algae-based biochar, aiding 4-nonylphenol biodegradation in waste-activated sludge.

Isoniazid Derived Schiff Base Metal Complexes: Synthesis, Characterization, Thermal Stability, Antibacterial and Antioxidant Activity Study

Transition metal complexes of Cu2+, Ni2+ and Co2+ with the Schiff base ligand, N-(2-methoxybenzylidene)isonicotinohydrazone, (L1) were synthesized by the conventional condensation approach. Ligand and its metal were characterized by FT-IR, UV-Vis, Magnetic moment measurements and Thermogravimetric (TGA) analysis. IR spectra revealed that the Schiff base ligand coordinated to the metal ion through nitrogen (N) of azomethine group and oxygen (O) of carbonyl group. IR data coupled with TGA analysis confirmed the presence of coordinated water molecules. Antibacterial activity for both ligand and its complexes were investigated against some pathogenic bacteria and the best activity was observed in the case of the CuL1 against E. coli when compared with standard drug, Kanamycin-30. The antioxidant activity of the CuL1 complex was the greatest among all the complexes when compared to that of BHT.

Synthesis, spectroscopic, anti-bacterial activity, molecular docking, ADMET, toxicity and DNA binding studies of divalent metal complexes of pyrazole-3-one azo ligand

Treatment equivalent molar of pyrazole-3-one azo (HPyoz) ligand with divalent metal ions {Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)} afforded complexes of the chemical formula [MCl2(H2O)2(HPyoz)] {Co(II), Ni(II), and Cu(II)} or [MCl2(HPyoz)] {Zn(II), Cd(II) and Hg(II)}. The prepared complexes were characterized using IR, 1H, 13C NMR, Uv-visible spectra, xrd, SEM, conductance, and magnetic measurements. The results refer to that the HPyoz ligand behaves as bidentate via the nitrogen of azo group and oxygen of carbonyl group to afforded an octahedral complexes around transition metal ion {Co(II), Ni(II), and Cu(II)} or tetrahedral geometry around 12B group ions {Zn(II), Cd(II) and Hg(II)}. The results obtained from xrd and SEM images unequivocally declared the nano-sized of the prepared complexes. The lately studied compounds were examined for anti-bacterial activities towards four pathogenic species of bacteria. Molecular docking had been done based on screening against different targets, that show the good binding affinity of tested compounds with nucleoside diphosphate kinase (target site PDB ID: 3Q89), it's an important enzyme that generates nucleoside triphosphates (NTPs) or their deoxy derivatives by terminal phosphor-transfer from an NTP such as ATP or GTP to any nucleoside diphosphate or its deoxy derivative. As NTPs, particularly GTP, are important for cellular macromolecular synthesis and signaling mechanisms, Ndk plays an important role in bacterial growth, signal transduction and pathogenicity. In addition, The DNA binding properties of prepared complexes were evaluated. The intrinsic binding constant is calculated as 6.79 × 105, 4.72 × 105, 1.89 × 105 and 4.12 × 105M − 1 for the Ni-complex, Co-complex, Cu-complex and Zn-complex, and these results establish good binding characteristics of the prepared complexes with DNA

Thermal and spectroscopic studies of some metal complexes with a new enaminone ligand 3-chloro-4-((4-methoxyphenyl)amino)pent-3-en-2-one and their investigation as anti-urease and cytotoxic potential drugs

Complexes of transition metals [Co(II), Cd(II) and Mo(0)] with a new enaminone (PA) 3 -chloro-4-((4-methoxyphenyl)amino)pent-3-en-2-one were synthesized and afterwards characterized by 1 H NMR, 13 C NMR, FAB-MS, UV–Vis, ICP-OES, TGA and FTIR. The spectroscopic and conductance data suggested that the ligand (PA) is attached to the metal ions in bidentate, neutral form through the nitrogen atom of amino group and the oxygen of carbonyl group. Metal complexes displayed octahedral geometries. In vitro urease inhibition and cytotoxic activities of all the compounds were evaluated. Results revealed that Co(II) complex (PA-Co) was even more significant than the reference drug thiourea. Analysis of the cytotoxicity indicated that, the Co(II) complex has more cytotoxic effect than enaminone ligand and other complexes when assessed on the human cancer cell lines MCF-7.Molecular docking simulation was also performed to find out the putative binding mode within the target protein.

In vitro Synthesis, Structure Elucidation, and Antioxidant Properties of Platinum(IV)-hydrazide Complexes: Molecular Modeling of Free- Hydrazides Suggested as Potent Lipoxygenase Inhibitor.

A combination of biologically active ligand and metal in one molecule may increase the activity and reduce the toxicity. In this study, the synthesis and characterization of platinum(IV) complexes with bioactive hydrazide ligands are discussed. Elemental analysis, conductivity measurements, and spectroscopic studies were used to elucidate the structure of complexes. Our study suggests that hydrazide ligands coordinate with Pt(IV) in a bidentate fashion. The platinum(IV) complexes have octahedral geometry with a metal to ligand ratio of 1:2. Hydrazide ligands were coordinated with central metal platinum(IV) by oxygen of carbonyl group and nitrogen of primary amine. Synthesized complexes exhibited variable DPPH radical scavenging and lipoxygenase inhibition activity. Furthermore, it is also found that Pt(IV)-hydrazide complexes are more potent superoxide and nitric oxide radical scavengers than their uncoordinated hydrazide ligands, while in the case of lipoxygenase enzyme inhibition, some of the free hydrazide ligands are more active than their respective Pt(IV) complexes. In silico docking technique explores molecular interactions of synthesized ligands in the active site of the lipoxygenase enzyme. Predicted docking energies are in good agreement with experimental data suggesting that in silico studies might be useful for the discovery of therapeutic candidates. Structure-function relationship demonstrates that the radical scavenging and enzyme inhibition activities of the Pt(IV) compounds are affected by the nature of the ligand, position of substituent, electronic and steric effects. However, electronic factors seem to play a more important role than other factors.

Synthesis and Characterization of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-Carboxy benzaldehyde Aroylhydrazones

A new metal complexes have been synthesized by a reaction of metal compounds contained Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with two kinds of ligands that are 2-carboxy benzaldehyde 4-methylbenzoylhydrazone(CBMH) and 2-carboxy benzaldehyde picolinoyl hydrazine (CBPH), the ligands (CBMH and CBPH) were prepared by condensation of 2-carboxy benzaldehyde with 4-methylbenzoyl hydrazide or picolinoyl hydrazide, respectively. In fact, complexes[M(L-H)2]. xH2O were characterized by elemental analysis, molar conductance, magnetic susceptibility, and spectral measurements (UV-Vis, IR,). The hydrazones CBMH and CBPH act as monobasic tridentate ligands, in all their complexes. The ligand CBMH coordinated to the metal ions through the azomethine nitrogen, the carboxyl group oxygen, and the amide carbonyl group oxygen atoms, while the ligand CBPH coordinated through the carboxyl group oxygen, the azomethine nitrogen, and the pyridine ring nitrogen atoms. Physico-chemical studies suggest octahedral geometry for all metal(II) complexes.

Synthesis, characterization and solid state conductivity of nitro-phenol-benzaldehyde urea based ligand and trithiocarbonate

The heterobimetallic complexes and related compounds are the area of interest fortheir widespread applications in materials science and the biological field.Mixed heterobimetallic ligand complexes of type [M(CS3)2][M'(L)2], [CuCo(CS3)2(L)2] and [Cu(CS3)2][VO(L)2·H2O] have been formulated and spectroscopically characterized using IR, 1H &13C NMR, UV–Visible, and ESR spectroscopy (where M = Cu(II) and M'= Ni(II) Co(II), & Zn(II) and L = 4-nitro-phenol –benzaldehyde-urea based ligand (L). The powder XRD spectra of the bimetallic complexes and solid-state electrical conductivity at variable temperature were also analyzed. The IR data suggest an involvement of (–NH2) group and oxygen of carbonyl group of the phenolic ligand in complexation with metal. The magnetic susceptibility measurement and e.s.r data support the metal–metal interaction in these complexes. The powder XRD patterns of the complexes show a semicrystalline nature of these complexes. These compounds have a semiconducting property and the band gap of these complexes are in the range of0.85–2.20 eV.

Preparation, characterization and biological activity study of Co (II), Ni(II) and Cu(II) Complexes with 4-(( Z)-4-bromobenzylidene)-2-(7-((4-bromobenzylidene) amino)-3-methyl-8-oxo-5-thia-1-azabicyclo [4.2.0] oct-2-en-2-yl)-oxazol-5(4H)-one derivatives

New succession related to the transition metal complexes Cu(II), Ni(II), and Co(II) with 4-((Z)-4-bromobenzylidene)-2-(7-((4-bromobenzylidene)amino)-3methyl-8oxo-5-thia-1azabicyclo[4.2.0]oct-2-en-2yl)oxazol-5(4H)-one) has been prepared and described. The structural descriptions have been reached from FT-IR, molar conductance measurements, magnetic susceptibility UV-Vis ,flame atomic absorption techniques as well as 1HNMR. Based on those results, it is proposed that the coordinates of the ligand to metal ions from the nitrogen related to azomethine group as well as the oxygen of carbonyl group. In addition, the biological activity of complexes and ligand has been investigated opposite Staphylococcus aureus, Aspergillus Niger, Ecoli, and Candida albicans. The products indicate that Co (II)-complex, Ni (II)-complex and Cu (II) -complex is enhanced the biological activity in comparison to ligand.

A novel electrocatalytic filtration system with carbon nanotube supported nanoscale zerovalent copper toward ultrafast oxidation of organic pollutants

In this study, we designed an integrated electrochemical filtration system for catalytic activation of peroxymonosulfate (PMS) and degradation of aqueous microcontaminants. Composites of carbon nanotube (CNT) and nanoscale zero valence copper (nZVC) were developed to serve as high-performance catalysts, electrode and filtration media simultaneously. We observed both radical and nonradical reaction pathways, which collectively contributed to the degradation of model pollutants. Congo red was completely removed via a single-pass through the nZVCCNT filter (τ <2 s) at neutral pH. The rapid kinetics of Congo red degradation were maintained across a wide pH range (from 3.0–7.0), in complicated matrixes (e.g., tap water and lake water), and for the degradation of a wide array of persistent organic contaminants. The superior activity of nZVCCNT stems from the boosted redox cycles of Cu2+/Cu+ in the presence of an external electric field. The flow-through design remarkably outperformed the conventional batch system due to the convection-enhanced mass transport. Mechanism studies suggested that the carbonyl group and electrophilic oxygen of CNT served as electron donor and electron acceptor, respectively, to activate PMS to generate •OH and 1O2via one-electron transport. The electron-deficient Cu atoms are prone to react with PMS via surface hydroxyl group to produce reactive intermediates (Cu2+-O-O-SO3−), and then 1O2 will be generated by breaking the coordination bond of the metastable intermediate. The study will provide a green strategy for the remediation of organic pollution by a highly efficient and integrated system based on catalytic oxidation, electrochemistry, and nano-filtration techniques.

Synthesis and characterization of substituted acetophenone-4, 4-dimethyl-3-thiosemicarbazone derivatives with an evaluation of antimicrobial and antioxidant activities

Thiosemicarbazones are organic compounds; these are widely used in the medical field. It is primarily in the manufacture of pharmaceutical drugs and bio molecules. These compounds have the azomethine functional group (-N=CH-) used to derive organic open chain and heterocyclic compounds. Thiosemicarbazones are similar to semicarbazones, and carbonyl group oxygen is replaced by sulphur. Thiosemicarbazone contains nitrogen and sulfur atoms, so they are used as ligands in coordination chemistry and form metal complexes. Thiosemicarbazone and its metal complexes are used in a variety of ways. It is especially widely used in the preparation of polymers and biochemicals products. Thiosemicarbazone and its metal complexes are closely correlated with biological properties and act as antioxidants, antifungals, antimicrobials and anticancer. Subsequently, in the current study, substituted thiosemicarbazones were synthesized and examined for their antimicrobial and antioxidant activity. Newly substituted thiosemicarbazones were obtained from the respective acetophenones and thiosemicarbazides. The structure of the newly prepared compounds was confirmed by spectroscopic studies such as IR, 1H, 13C NMR, Mass and elemental analysis. The antimicrobial activity of all the new compounds showed significant activity against the selected bacteria and fungi in the studies. The compound TZ04 exhibited good antioxidant activity compared with standard ascorbic acid and butylated hydroxytoluene.

Dehydration-fragmentation mechanism of cathinones and their metabolites in ESI-CID.

Various cathinone-derived designer drugs (CATs) have recently appeared on the drug market. This study examined the mechanism for the generation of dehydrated ions for CATs during electrospray ionization collision-induced dissociation (ESI-CID). The generation mechanism of dehydrated ions is dependent on the amine classification in the cathinone skeleton, which is used in the identification of CATs. The two hydrogen atoms eliminated during the dehydration of cathinone (primary amine) and methcathinone (secondary amine) were determined, and the reaction mechanism was elucidated through the deuterium labeling experiments. The hydrogen atom bonded to the amine nitrogen was eliminated with the proton added during ESI, in both of the tested compounds. This provided evidence that CATs with tertiary amine structures (such as dimethylcathinone and α-pyrrolidinophenones [α-PPs]) do not undergo dehydration. However, it was shown that the two major tertiary amine metabolites (1-OH and 2″-oxo) of CATs generate dehydrated ions in ESI-CID. The dehydration mechanisms of the metabolites of α-pyrrolidinobutiophenone (α-PBP) belongs to α-PPs were also investigated. Stable-isotope labeling showed the dehydration of the 1-OH metabolite following a simple mechanism where the hydroxy group was eliminated together with the proton added during ESI. In contrast, the dehydration mechanism of the 2″-oxo metabolite involved hydrogen atoms in three or more locations along with the carbonyl group oxygen, indicating that dehydration occurred via multiple mechanisms likely including the rearrangement reaction of hydrogen atoms. These findings presented herein indicate that the dehydrated ions in ESI-CID can be used for the structural identification of CATs.

Synthesis of Hydroxamic Ligands with Transition Metal Complexes, their Biological Activities and Characterization Through Spectroscopic Techniques

New metal complexes including Ni (Ⅱ), Co (Ⅱ), Cu (Ⅱ), Fe (Ⅲ), Cr (Ⅲ), Cd (Ⅱ) and Zn (Ⅱ) have been synthesized from parent ligand N-methyl m-nitrobenzohydroxamic acid. The condensation ratio is 2:1 of the ligand and metal salt (MX) in methanol. The ligand N-methyl m-nitrobenzohydroxamic has been prepared by the interaction of N-methylhydroxylamine hydrochloride with m-nitrobenzoyl chloride. The coordination modes and bonding of the ligands along with its metal complexes have been identified by FT-IR, 1H-NMR and UV-Vis spectroscopic techniques. It has been enumerated by spectroscopic techniques that the complex is formed via O, O-coordination to metal through the oxygen of carbonyl group and deprotonated hydroxyl group. The antibacterial and antifungal activities of the ligand as well as its complexes have been estimated against two gram negative strains such as Escherichia coli and Salmonella typhi, one gram positive strain Escherichia coli and one fungal strain yeast. In addition to this the cytotoxicity and antitumor activities have been evaluated resistant to Brine shrimps eggs and Hela cell line respectively.