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Extraordinary specific breaking of the carbon-sulfur linkage of the thiosemicarbazone moiety from a Schiff base has been watched the blue, bringing about the development of a four coordinated tetra CuII cubane containing triphenyl phosphine and µ3-S as ligands. At the same time, the ketimine group of the Schiff base ligands also got ruptured to regenerate the diketone used for the synthesis of thiosemicarbazone ligand. The synthesized complex was spectrally and structurally investigated. The crystallographic information reveals that the complex is having the shape of a cubane, where as the alternate four corners were occupied by tricoordinated copper and the other corners are by µ3-S respectively. µ3-S behaves as a ligand which is having the binegative site and neutral site to get bonded with the copper as bridging ligand. Antimicrobial and antioxidant efficacy were explored and shows a better results than the controls used.

The growing global demand for renewable energy sources has pushed renewable, green energy sources to the forefront, among which the production of hydrogen gas from water occupies a significant place. To realize this goal, researchers across the globe are developing various systems that could swiftly catalyze the hydrogen evolution reaction (HER) in the highest possible yield. In the present work, the electrocatalytic HER performances of pyridoxal semicarbazone- and thiosemicarbazone-based Cu(II) complexes, i.e., ([Cu(PLSC)Cl2] and [Cu(PLTSC-H)H2O]Br?H2O) are reported. It has been unambiguously demonstrated that the complexes exhibit enviable level of HER catalytic activity. The catalytic activity of the complexes was not only the function of central metal but it was also controlled by the nature of the coordinating ligand.

The terminal N-mono- and dimethylated derivatives of an estrone–salicylaldehyde thiosemicarbazone hybrid and their highly cytotoxic Cu(II) complexes were synthesized and characterized in addition to their structurally related simpler bicyclic analogues. Solution stability and structure of the complexes were determined by UV–visible spectrophotometry and electron paramagnetic resonance spectroscopy. The monomethylation has a minor influence on the pKa values, while the dimethylation results in somewhat more acidic derivatives compared to the non-methylated derivatives, although all the compounds are neutral at physiological pH. Based on the speciation studies performed in a 30% (v/v) dimethyl sulfoxide/water mixture, the four novel ligands form fairly high-stability complexes with Cu(II) ions, in which they coordinate in mono-anionic (O‒,N,S) or di-anionic (O‒,N,S‒) binding modes. [CuLH‒1] species with (O‒,N,S‒)(H2O) coordination mode are present in solution at neutral pH, and these complexes were isolated and further studied. The Cu(II) complexes formed with the estrone hybrids were more stable in comparison with the bicyclic analogues. The terminal N-dimethylation results in the most stable complexes in a given ligand series. In vitro cytotoxicity of all the Cu(II) complexes was measured in 3D spheroids of HCT-116, A-549 and CH-1 human cancer cells which showed fairly low IC50 values (3.9‒17.1 μM). The Cu(II) complexes caused reduced tumour growth, and they activated the caspase-3 and caspase-7 endoproteases leading to apoptosis except the case of the complex formed with the monomethylated bicyclic derivative, where other type of mechanisms of action seems to induce the cell death. Anticancer Cu(II) complexes of mono- and dimethylated salicylaldehyde thiosemicarbazone-estrone hybrids possessing high solution stability and strong cytotoxic effect against 3D spheroids of a series of human cancer cells. 398x273 mm (150 x 150 DPI)

Aryl hydrazones bearing thiazolyl coumarin hybrids 1–32 were prepared by following 'one-pot' two-steps reaction scheme. Various arylaldehydes were reacted to thiosemicarbazide under acidic condition to form aryl thiosemicarbazone intermediates which in turn treated with 3-bromoacetyl coumarin under basic condition to afford thiazolyl coumarin hybrids 1–32. All hybrids were recognized by EI- and HREI-MS and 1H- and 13C-NMR spectroscopic techniques. Compounds 1–32 were screened for in vitro inhibitory activity against urease enzyme and displayed good to moderate inhibitory potential in the ranges of IC50 = 16.29 ± 1.1–256.30 ± 1.4 µM. Worth stating that compound 21 (IC50 = 16.29 ± 1.1 µM) was identified as more potent urease inhibitor than the standard acetohydroxamic acid (IC50 = 27.0 ± 0.5 µM). Derivatives 19 (IC50 = 77.67 ± 1.5 µM) and 30 (IC50 = 71.21 ± 1.6 µM) were found to be moderately active. Structure–activity relationship revealed that -F, -Cl, -OH, and -OMe groups and their respective positions on aryl ring are playing important role in urease enzyme inhibition. Molecular docking studies identified important interaction between the ligand (active hybrids) and urease active site.

The X-ray diffraction study of three compounds containing 2,3-dihydroxybenzaldehyde semicarbazone (H3L1) or 2-hydroxy-3-methoxybenzaldehyde semicarbazone (H2L2) shows the formation of one organic salt with protonated triethylamine [(C2H5)3NH][H2L1]·0.5(CH3)2CO (I) and two new coordination nickel(II) compounds with these two differently substituted semicarbazones of salicylaldehyde [Ni(H3L1)(H2L1)](NO3)·2.5MeOH·0.25H2O (II) and [Ni(H2L2)2]Cl2·4H2O (III) (CIF files CCDC nos. 2041894–2041896 (I–III)). The Ni(II) compounds are ionic and formed by the complex cations with the same metal to ligand ratio. The Ni(II) ion in these complex cations is characterized by a distorted octahedral coordination geometry formed by a set of donor atoms N2O4 of two ligands coordinated via the tridentate mode. In the monocharged complex cation of compound II, two coordinated ligands are not identical. One of them acts as the neutral chelating agent (H3L1), and the second ligand is deprotonated and involved as the monoanion (H2L1)–. Both H2L ligands are neutral in the complex cation of compound III. In the crystal, all the three compounds form supramolecular ensembles of diverse dimensionality and architecture, and their components are joined by weak interactions of different types.

Thiosemicarbazides have the capability of killing the cancerous tumor cells and inhibit the growth of bacteria and fungus. Here, we designed and synthesized a calix[4]arene-based thiosemicarbazone Schiff-base ligand, and the derivative complexes with Co (II), Ni (II), Cu (II), and Zn (II) transition metals. All compounds were characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, 1H-NMR, and ESI-Mass spectroscopy to confirm the successful synthesis. We further evaluated the biocompatibility and biological inhibitory properties of our newly synthesized complexes in human cell lines. The antibacterial activity of the ligand and derivative complexes with cobalt, nickel, copper, and zinc showed that they are all more active against gram-negative bacteria than against gram-positive ones. Hemolysis assay results demonstrated that Zn and Ni complexes have high blood compatibility in high (1600 mg L−1) and low (25 mg L−1) concentrations, respectively. MTT assay showed the substantial anticancer activity of Cu complex against the MG-63 cell line.

A new thiosemicarbazone derivative ligand N-(4-chlorophenyl)-2-(pyridin-2-ylmethylene)hydrazine-1-carbothioamide (HL) and its zinc(II) complex [ZnL2]·CH2Cl2 (1) are prepared and characterized by elemental analysis, FTIR and 1H NMR spectroscopy, and single crystal X-ray diffraction (for 1). The X-ray analysis reveals that the zinc atom is octahedrally coordinated by two NPyNimineSthiolate -donor ligands with the mer form. The HL ligand is deprotonated during the complexation process through the thiol group. In the crystal network of 1, the N–H⋯S hydrogen bonds form $$\text{R}_{2}^{2}$$ (8) hydrogen bond motifs. In addition, the crystal network is more stabilized by π–π stacking and C–H⋯π interactions. The ability of complex 1 to interact with ten selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II, and B-DNA) is investigated by docking studies. The results show that in many cases, complex 1 can interact with proteins better than doxorubicin.

Sulphur-nitrogen(SN) donor thiosemicarbazone ligand [(Z)-N-ethyl-2-(5-methyl-2-oxoindolin-3-ylidene)hydrazinecarbothioamide] and its Pt(II) complex were synthesized by condensation method. The compounds were structurally characterized by elemental analysis CHNS, FT-IR, and NMR analysis. The elemental analyses data for the compounds were in good agreement with the theoretical values. The melting point of the complex was higher than the ligand, as expected. The FT-IR spectral data reflect a bidentate bonding of thiosemicarbazone ligand to Pt(II) ion through thioketo sulfur and azomethine nitrogen. The docking results (theoretical results) of these compounds show that the binding energy between DNA and Pt(II) complex was found to be less than that of the Schiff base ligand (L) in the sense that it has higher stability at various stages and angles. The strength of docking between DNA and Pt(II) complex was also found to be that stronger than the Schiff base ligand (L).

Schiff bases are versatile ligands, synthesized via condensation of primary amines with carbonyl compounds. In this study, equimolar amounts of 4-imidazolecarboxaldehyde and thiosemicarbazide were combined and the Schiff base 4-imidazolecarboxaldehyde thiosemicarbazone was prepared as a new bidentate complexing agent. The synthesized ligand was reacted with palladium (II) and platinum (II) ions yielding air-stable complexes. For characterization purpose, infrared spectra, mass spectra, electronic spectra, thermal analysis, proton nuclear magnetic resonance and 13-carbon nuclear magnetic resonance spectra studies were carried out on the obtained complexes and ligand. The characterization data showed that the ligand acts as a bidentate coordinate to the metal ions through azomethine nitrogen and sulfur atoms. An in vitro antimicrobial investigation was also carried out for the free ligand and its metal complexes against four bacteria; Bacillus cereus, Staphylococcus aureus (Gram-positive), Escherichia coli and Salmonella typhimurium (Gram-negative) and one Fungi; Candida albicans, to assess their antimicrobial properties by disc diffusion technique. Antimicrobial activity of the prepared complexes showed higher activity than the free ligand.

Mixed ligand metal complexes of azo quinoline and thiosemicarbazone with Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) metal ions were synthesized. The structure and possible geometry of all the metal(II) complexes were analyzed and supported by IR, mass spectrum, elemental analysis, TG-DTA, electronic spectra (UV), magnetic susceptibility and molar conductance. The synthesized compounds were studied for their antibacterial, antifungal and antimalarial activities. The antimicrobial activity was carried out against bacteria (two Gram-positive bacteria and two Gram-negative bacteria), three fungal strain and one malarial pathogen

In this study, we report the synthesis of a series of new gold compounds in different solvation media. First, gold(I) thiosemicarbazone (TSC) [Au–(TSC)2]Cl was synthesized by reacting [Au(SMe2)]Cl with a thiosemicarbazone ligand in acetonitrile. Then, we successfully managed to replace one of the monodentate thiosemicarbazone ligands with Cl to prepare the TSC–AuCl complex by the reaction of KAuCl4 with thiosemicarbazone in acetonitrile. In a different strategy, the reaction of KAuCl4 with thiosemicarbazone in methanol formed a [TSC–AuCl]AuCl2 complex of tridentate (NNS) thiosemicarbazone. All complexes were fully characterized by X-ray diffraction, 1H and 13C NMR spectroscopy, and mass spectrometry. The 1H and 13C NMR spectra of the [Au–(TSC)2]Cl in DMSO-d6 solution showed two sets of signals, suggesting the presence of two complexes formed from (E)- and (Z)-TSC, respectively. X-ray studies showed only one complex from (Z)-TSC, and the (Z)-TSC ligands provide an exactly linear coordination arrangement around the Au(I) centres. X-ray crystallography showed [TSC–AuCl]+ cations in the AuCl2 salts to have a square pyramidal geometry. Complexes of TSC–AuCl and [TSC–AuCl]AuCl2 had limited stability, decomposing rapidly in solution, while the [Au–(TSC)2]Cl complex was stable in solution.

Heptacoordinated metal complexes with a pentadentate ligand 2,6-diacetylpyridine-bis(thiosemicarbazone) (H2daptsc) were used for the first time ever as building blocks to create polynuclear multifunctional molecular materials. Reactions of the paramagnetic [Mn(II)(H2daptsc)(H2O)2](ClO4)2 and [Mn(II)(H2daptsc)Cl2] complexes with photochromic sodium nitroprusside Na2[Fe(II)(CN)5NO].2H2O were studied. As a result, six polynuclear phases were obtained: {Mn(H2daptsc)Fe(CN)5NO}n·0.5n(MeOH)·0.5n(H2O) (1), {Mn(H2daptsc)Fe(CN)5NO}3n·8n(MeOH) (2), {Mn(H2daptsc)Fe(CN)5NO}2n·n(MeOH)·n(H2O) (3), [Mn(H2daptsc)Cl]2[Fe(CN)5NO] (4), {Mn(H2daptsc)Fe(CN)5NO}n·2n(H2O) (5) and {Mn(H2daptsc)Fe(CN)5NO}n·n(EtOH) (6). The crystal structures of the phases as well as the magnetic and photochromic properties of 1 and 4 were studied.

Ru(II)BT have been synthesized by the reaction between substituted bromobenzal thiosemicarbazones and precursors of ruthenium metal complexes, [RuHCl(CO)(EPh3)3] (where E = P/As). The bromobenzal thiosemicarbazones and Ru(II)BT was characterized by analytical and spectroscopic techniques. It confirms the coordination of the thiosemicarbazone ligands and suggest the octahedral geometry of the complexes. The Ru(II)BT is comprised of a metal centre with bidentate ligands. The stabilization of free radicals with Ru(II)BT was studied. The ligand and Ru(II)BT have significant anticancer activity on MCF-7 cancer cells.

Two square?planar complexes, [PtLCl] (1) and [PdLCl] (2), were synthesized with quinoline-2-carboxaldehyde thiosemicarbazone ligand (HL), and characterized by IR and NMR spectroscopy and single crystal X-ray diffraction analysis. In both complexes, L- is coordinated tridentately via the same donor atom set, while the fourth coordination site is occupied by a chloride ion. However, the complexes are not isostructural due to different types of non-covalent intermolecular interactions. These interactions were analyzed using Hirshfeld surfaces and two-dimensional fingerprint plots.

A new poly (vinyl chloride) (PVC) membrane electrode using 2-benzoylpyridine semicarbazone as membrane carrier with dioctylphthalate as plasticizer and sodium tetraphenylborate (NaTBP) as anion excluder has been fabricated and investigated as Zn(II)-selective electrode. Best potential response is observed for the composition PVC 30%, plasticizer 58%, NaTBP 8% and ionophore 4% (w/w). The sensor showed a linear stable response over a concentration range of 1.0 × 10−2–4.56 × 10−6 M with a detection limit of 2.28 × 10−6 M and a response time

In this work, pyridine 4-carbaldehye semicarbazone Schiff base ligand (HL) was synthesized with condention of pyridine 4-carbaldehyde and semicarbazide hydrochloride in reflux method. The HL was characterized using the CHN elemental analysis, FT-IR, UV-Vis, and 1H NMR spectroscopy. The single crystals of HL prepared and used for the X-ray crystallography. Single-crystal X-ray diffraction revealed that, HL crystallized in a triclinic system with the space group P-1. The FT-IR spectra and X-ray crystallography results suggested that the HL ligand is in keto form.

The synthesis and characterization of three new platinum complexes, with 3,5-diacetyl-1,2,4-triazole bis(4-N-isopropylthiosemicarbazone) as a ligand, are reported. The specific conditions under which solvent coordination takes place are reported and the X-ray structure of the complex with one solvent molecule of dimethyl sulfoxide is resolved. Analysis of the reactivity of these platinum compounds aids in finding the best solution profile for biological investigations. Then, the interactions of the complexes with biological models, such as calf-thymus DNA, are studied by using UV spectroscopy and tracking the changes in electrophoretic mobility produced in the supercoiled plasmid DNA model. Initial screening of these potential antitumoral compounds indicates possible selective antitumoral action.

An interesting series of five new cobalt complexes of 2-benzoylpyridine-N-4-phenyl semicarbazone(HL1) and 2-acetylpyridine-N-4-phenyl semicarbazone(HL2) have been synthesized and physico chemically characterized. Cobalt(III) and various tridentate ligands form mainly mixed bis(ligand) complexes. Cobalt(III) complexes of the type [CoL2]X (X = Cl, Br, SCN, N3, NO3 etc., L = anion from the enol form of the semicarbazone ligand of the type, HL) which were proposed to be low-spin, diamagnetic and octahedral have been reported. Ligand can exist in keto or enol form or an equilibrium mixture of the two since it has an amide NH-C (O) function. However, the IR spectrum of HL1 and HL2 indicates that in the solid state it remains in keto form. The IR spectra of complexes, however, do not show any intense absorption bands around 1698 cm−1 and 1683 cm−1, due to the carbonyl stretching of the semicarbazone moiety. This shows that in solution, it tautomerises to the enol form and coordinates to the metal in the enolate form. A medium band in the region 3380 cm−1 in the free ligands due to v(N–H) vibration disappears in the spectra of complexes providing a strong evidence for the ligand coordination around cobalt(III) ion in its deprotonated form. Both the semicarbazones and their cobalt(lII) complexes show aring ᴨ → ᴨ * band in the range 37000–39000 cm−1 and an n → ᴨ* band in the range 32000–34000 cm-l involving transitions within the semicarbazone moiety.

A variant of 1,4,7,10-tetraazacyclododecane (cyclen) bearing two semicarbazone pendant groups has been prepared. The octadentate ligand forms complexes with Bi3+ and Pb2+. X-ray crystallography showed that the neutral ligand provides an eight-coordinate environment for both metal ions and intermolecular hydrogen bond interactions have influenced the coordination environments of both complexes in the solid state. NMR spectroscopy revealed a fluxional environment for both complexes. The ligand was radiolabeled with the α-emitting radioactive isotope 213Bi3+, which is used in systemic targeted radiotherapy. The resulting complex was stable in serum for at least 90 min (two decay half-lives). The Pb2+ complex has reasonably fast kinetics of formation (t1/2 = 20 min) at 25 °C and pH 7.4. The Bi3+ and Pb2+ complexes show kinetic stability in 1.2 M HCl (half-lives of 214 min and 47 min, respectively). This is the first description of a macrocycle bearing semicarbazone pendant groups and its utility in coordinating main group metals, specifically those with radiotherapeutic potential.

This work describes the preparation of a new thiosemicarbazone derivative, (Z)-N-ethyl-2-(6-oxo-1,10-phenanthrolin-5(6H)-ylidene)hydrazinecarbothioamide (phet) and its respective Re(i) tricarbonyl chloro complex, fac-[ReCl(CO)3(phet)]. The spectroscopic, photophysical and electrochemical properties of the new complex were fully investigated through steady state and time-resolved techniques along with computational calculations. In fac-[ReCl(CO)3(phet)], the new ligand is coordinated to the metal center through the pyridyl rings of the phenanthroline moiety. The unbound electron pairs in the S atom of the bending thiosemicarbazone group induce new low energy lying electronic transitions. Consequently, enhanced visible light absorption up to 550 nm is observed in acetonitrile due to the overlap between MLCTRe→phet and ILphet(n→π*) transitions. The absorption bands and emission quantum yields of fac-[ReCl(CO)3(phet)] are sensitive to proton concentration due to an acid-basic equilibrium in the N atoms of the thiosemicarbazone. Proton dissociation constants of 10.0 ± 0.1 and 11.4 ± 0.2 were determined respectively for the ground and excited states of the new complex. Spectral changes could also be observed in the presence of Zn2+ cations which can be further explored for sensing applications. The electrochemical behavior of the new complex was studied in detail, revealing up to four one electron reduction processes in the range from 0 to -2.4 V vs. Fc+/Fc. With support of DFT calculations, the first three processes are ascribed to the reduction of the coordinated phet ligand followed by the ReI/0 reduction and consequent Cl- release. The new complex was able to act as an electrocatalyst for CO2 reduction into CO (Eonset = -1.92 V vs. Fc+/Fc), with a turnover frequency of 2.81 s-1 and turnover number of 24 ± 1 in anhydrous acetonitrile, being the first Re(i) tricarbonyl complex with a thiosemicarbazone derivative described for this goal. The detailed characterization carried out here can drive the development of new Re(i)-thiosemicarbazone derivatives for different applications.

A simple Schiff-base ligand 2-hydroxy-1-naphthaldehyde semicarbazone (HNS) was synthesized and characterized. Based on the combined effect of inhibition of CHN isomerization and chelation-enhanced fluorescence (CHEF), HNS functions as a fluorescence “turn on” sensor for Al3+ in buffered aqueous media. Based on the strong affinity of Al3+ to F− ions, the in situ generated Al3+–HNS complex can also be utilized as an effective chemosensor for F− sensing by metal displacement approach, ensuing quenching of fluorescence by the reversible return of HNS from Al3+–HNS complex. Thus a method using a single probe for the detection of both Al3+ and F− ions is developed. The system exhibits high selectivity and sensitivity for Al3+ and F− ions and the detection limits were found to be as low as 6.75 × 10−8 M and 7.89 × 10−7 M, respectively. Furthermore, the practical applicability of this probe has been examined in living cells.

[Resumen] El presente trabajo comprende la síntesis y caracterización estructural de ocho compuestos con potencial actividad fitosanitaria: dos semicarbazonas y dos tiosemicarbazonas derivadas de la 2-acetilpiridina, así como sus respectivos complejos derivados de zinc(II). Las semicarbazonas L1 y L2, y las tiosemicarbazonas L3 y L4 fueron sintetizadas mediante la condensación en etanol, bajo calentamiento con reflujo, de 2-acetilpiridina con las correspondientes semicarbazidas y tiosemicarbazidas, respectivamente. Los ligandos L1, L2, L3 y L4 se hicieron reaccionar con acetato de zinc dihidratado en las mismas condiciones con el fin de formar los compuestos de coordinación C1, C2, C3 y C4. Los ligandos semicarbazona y tiosemicarbazona se comportan, respectivamente, como quelatos tridentados [N,N,O] y [N,N,S]. La caracterización de los diferentes compuestos sintetizados fue realizada mediante las técnicas de espectroscopía de RMN de 1H y 13C-{1H}, espectrometría de masas, espectroscopía de IR y medidas de conductividad molar. [Resumo] O presente traballo comprende a síntese e a caracterización estrutural de oito compostos con potencial actividade fitosanitaria: dúas semicarbazonas e dúas tiosemicarbazonas derivadas da 2-acetilpiridina, así coma os seus respectivos complexos derivados de zinc(II). As semicarbazonas L1 e L2, e as tiosemicarbazonas L3 e L4 foron sintetizadas mediante a condensación en etanol, baixo quentamento con refluxo, de 2-acetilpiridina coas correspondentes semicarbazidas e tiosemicarbazidas, respectivamente. Os ligandos L1, L2, L3 e L4 se fixeron reaccionar con acetato de zinc dihidratado nas mesmas condicións co fin de formar os compostos de coordinación C1, C2, C3 e C4. Os ligandos semicarbazona e tiosemicarbazona se comportan, respectivamente, coma quelatos tridentados [N,N,O] y [N,N,S]. A caracterización dos diferentes compostos sintetizados foi realizada mediante as técnicas de espectroscopía de RMN de 1H e 13C-{1H}, espectrometría de masas, espectroscopía de IR e medidas de conductividade molar. [Abstract] The present study is dedicated to the synthesis and structural characterization of eight compounds with potential phytosanitary activity: two semicarbazones and two thiosemicarbazones derived from 2-acetylpyridine, as well as their respective complexes derived from zinc(II). Semicarbazones L1 and L2, and thiosemicarbazones L3 and L4, were synthesized by condensation by heating under reflux in ethanol of 2-acetylpyridine with the corresponding semicarbazides and two thiosemicarbazides, respectively. The ligands L1, L2, L3 and L4 reacted with zinc acetate dihydrate under similar conditions in order to form the coordination compounds C1, C2, C3 and C4. The semicarbazone and thiosemicarbazone ligands behave as [N,N,O] and [N,N,S] tridentate chelates respectively. The synthesized compounds were characterized by 1H and 13C-{1H} NMR spectroscopy, mass spectrometry, IR spectroscopy and molar conductivity measurements. Traballo fin de grao (UDC.CIE). Química. Curso 2021/2022

Herein we demonstrate that copper(II)-diacetyl-bis(N4-methylthiosemicarbazone)(CuATSM), clinical candidate for the treatment of ALS and Parkinson's disease, is a highly potent radical-trapping antioxidant (RTA) and inhibitor of (phospho)lipid peroxidation. In THF autoxidations, CuATSM reacts with THF-derived peroxyl radicals with kinh = 2.2 × 106 M-1 s-1─roughly 10-fold greater than α-tocopherol (α-TOH), Nature's best RTA. Mechanistic studies reveal no H/D kinetic isotope effects and a lack of rate-suppressing effects from H-bonding interactions, implying a different mechanism from α-TOH and other canonical RTAs, which react by H-atom transfer (HAT). Similar reactivity was observed for the corresponding Ni2+ complex and complexes of both Cu2+ and Ni2+ with other bis(thiosemicarbazone) ligands. Computations corroborate the experimental finding that rate-limiting HAT cannot account for the observed RTA activity and instead suggest that the reversible addition of a peroxyl radical to the bis(thiosemicarbazone) ligand is responsible. Subsequent HAT or combination with another peroxyl radical drives the reaction forward, such that a maximum of four radicals are trapped per molecule of CuATSM. This sequence is supported by spectroscopic and mass spectrometric experiments on isolated intermediates. Importantly, the RTA activity of CuATSM (and its analogues) translates from organic solution to phospholipid bilayers, thereby accounting for its (their) ability to inhibit ferroptosis. Experiments in mouse embryonic fibroblasts and hippocampal cells reveal that lipophilicity as well as inherent RTA activity contribute to the potency of ferroptosis rescue, and that one compound (CuATSP) is almost 20-fold more potent than CuATSM and among the most potent ferroptosis inhibitors reported to date.

New Pb(II), Mn(II), Hg(II), and Zn(II) complexes, derived from 4-(4-chlorophenyl)-1-(2-(phenylamino)acetyl)thiosemicarbazone, were synthesized. The compounds with general formulas, [Pb(H2L)2(OAc)2]ETOH.H2O, [Mn(H2L)(HL)]Cl, [Hg2(H2L)(OH)SO4], and [Zn(H2L)(HL)]Cl, were characterized by physicochemical and theoretical studies. X-ray diffraction studies showed a decrease in the crystalline size of compounds that were exposed to gamma irradiation (γ-irradiation). Thermal studies of the synthesized complexes showed thermal stability of the Mn(II) and Pb(II) complexes after γ-irradiation compared to those before γ–irradiation, while no changes in the Zn(II) and Hg(II) complexes were observed. The optimized geometric structures of the ligand and metal complexes are discussed regarding density functional theory calculations (DFT). The antimicrobial activities of the ligand and metal complexes against several bacterial and fungal stains were screened before and after irradiation. The Hg(II) complex has shown excellent antibacterial activity before and after γ-irradiation. In vitro cytotoxicity screening of the ligand and the Mn(II) and Zn(II) complexes before and after γ-irradiation disclosed that both the ligand and Mn(II) complex exhibited higher activity against human liver (Hep-G2) than Zn(II). Molecular docking was performed on the active site of MK-2 and showed good results.

3-methoxysalicylidene N-alkyl-thiosemicarbazones (L) (where alkyl is propyl, butyl, pentyl or hexyl) were synthesized. The reaction of the ONS donor ligands with [MoO2(acac)2] in methanol yielded the mixed ligand complexes bearing a solvent molecule as co-ligand, [MoO2(L)MeOH)]. The ligands and complexes were characterized by using analytical and spectroscopic methods. As a representative sample, the dioxomolybdenum(VI) complex of the N4-butyl-substituted thiosemicarbazone was crystallographically examined to ensure the expected structures. X-ray data showed a distorted octahedral environment of molybdenum center. Tyrosinase, collagenase inhibition and antioxidant properties of the compounds were investigated using spectroscopic methods. The ligand and complexes exhibited the different inhibitory activities depending on N-alkyl substituents. Similarly, also the antioxidant capacity of the compounds changed in relation to the substituents.

Reaction of acetylacetone-S-methyl-thiosemicarbazone and 4-methoxy-salicylaldehyde in presence of Fe(ClO4)3 and NaN3 resulted in a mixed ligand complex, [Fe(L)N3], where L is N2O2-chelating thiosemicarbazidato ligand formed by template condensation. The first iron complex of the thiosemicarbazidato structure bearing a nitrogen ligand instead of chlorine in the 5th coordination site of iron(III) was characterized by using elemental analysis and spectroscopic methods. Crystallographic analysis clearly revealed the square pyramidal environment of iron(III) center. To support and compare the experimental data, the molecular geometries, vibrational frequencies, NMR chemical shifts, molecular electrostatic potential surface and HOMO-LUMO energies were performed by using DFT-B3LYP method. Formation of the iron(III) complex was explicated by identification the reaction intermediates using experimental and theoretical methods.

In this paper, we report the syntheses and crystal structuredetermination of three mononuclear and four-coordinated zinc(II) bromide complexes with chemical formula of [Zn(tsc)2]Br2 (1), Zn(PPh3)2Br2 (2) and Zn(Brcatsc)Br2 (3). The synthesized complexes are characterized by elemental analysis (CHN) and theircrystal structures are investigated by single crystal X-ray diffraction. In complex 1, the TSC coordinates to the zinc(II) ion as a bidentate ligand via N and S atoms. In complex 3, the thiosemicarbazone ligand Brcatsc coordinates to zinc(II) ion as a monodentate ligand via S atom. In these complexes, the zinc(II) ion coordinated in a distorted tetrahedral coordination geometry.

Two novel Cu(I) complexes with the 2-acetylpyridine-N(4)-phenyl semicarbazone (HL) ligand, [CuCl (HL)(PPh3)]∙CH3CN (1) and [CuBr (HL)(PPh3)] (2), were investigated by single-crystal X-ray analysis, Hirshfeld surface, and physicochemical and spectroscopic methods. In both cases, the Schiff base was coordinated by the bidentate ligand via the pyridine nitrogen and the iminic nitrogen atoms. A molecule of triphenylphosphine and a halide ion (Cl− or Br−) completed the coordination sphere of the metal centers. The geometry around the copper atoms was distorted tetrahedral geometry. The secondary coordination sphere of Cu(I) is pentacoordinated and has weak interactions Cu···O of 2.906(1) A and 2.783(1) A. The 3D Hirshfeld surface and the 2D fingerprint plots of the complexes were analyzed quantitatively to verify the presence of intermolecular interactions. By their crystal structure of (2), it is possible to observe π···π stacking interactions between the pyridyl and phenyl rings from HL and also between phenyl rings and the triphenylphosphine ligands forming a 1D network. The biological activity of the Cu(I) salts, the free semicarbazone, and its Cu(I) complexes was evaluated against human cancer cell lines MCF-7 and nontumor cell lines PBMC.

Four Cu(II) complexes [CuLH2O](ClO4)2, 1; [CuLCl]Cl.H2O, 2; [CuLBr]2(Cu3Br5), 3; and [CuLH2O](NO3)2, 4; where L = tetradentate semicarbazone ligand, have been synthesized and characterized by elemental analysis, FT-IR and UV–Vis. The structures of compounds 1 and 3 have been determined by single-crystal X-ray diffraction analyses. In mononuclear 1, the semicarbazone, L acts as a tetradentate neutral ligand and a water molecule also coordinates to the Cu atom. There are two independent [CuL(H2O)]2+ cations and four perchlorate anions in the crystallographic asymmetric unit. One of the cations has a weak interaction between its Cu atom and a O atom of an adjacent perchlorate anion. The structure of 3 contains two independent [CuLBr]+ cations and a (Cu3Br5)2− anion. The coordination geometry around the cation’s Cu(II) ion is five-coordinated square pyramidal, with L acting as a tetradentate neutral ligand and with a Br at the apical position. The Cu3Br 5 2− anions link to one another to form an infinite one-dimensional (Cu3Br 5 2− )n chain. Furthermore, the Hirshfeld surface analyses and the 2D fingerprint plot have been discussed.

The newly synthesized ligands (HL1-HL3) of 5-methoxyisatin thiosemicarbazone with different N-terminal substituents and their copper(II) complexes 1–3 respectively were exposed to spectral and structural characterization. The spectral studies reveal that the ligands show a tridentate mode of binding (ONS donor) with Cu(II) to form square planar complexes. The crystal structure of the ligand HL1 and complex 1 were confirmed by single crystal XRD. The compounds were subjected to DNA/BSA interaction studies using electronic and fluorescence spectroscopic techniques. The binding studies showed that, the complexes (1–3) were able to bind with DNA/BSA macromolecules with good binding constant. In which 1 ( K b = 0.83 × 105 M−1) shows good interaction with the DNA while 3 shows better interaction with BSA ( K b = 2.4 × 105 M−1). The complexes (1–3) were also tested for antimicrobial activity, radical scavenging activity and in vitro anti-proliferative activity. Complex 3 have shown potent efficacy with broad spectrum antimicrobial activity against the microorganisms, whereas the complex 1 has shown decent scavenging properties compared to the reference drug (ascorbic acid) with an IC50 value of 19.23 ± 1.05 µM. Further the, anti-proliferative activity study revealed that, the complex 1 has exhibited broad spectrum activity against MCF-7, A549 and HeLa with IC50 values 14.83 ± 0.45 μM, 17.88 ± 0.16 μM and 6.89 ± 0.42 μM, respectively compared to standard drug Doxorubicin.

A novel semicarbazone O2N donor ligand, HL, was synthesized by condensation of 2-aminochromone-3-carboxaldehyde with semicarbazide hydrochloride. The HL ligand is allowed to react with several copper(II) salts namely: AcO–, NO3–, SO42– and Cl–, in absence and presence of secondary ligand (SCN-, 8-HQ and 1,10-phen), forming binary and ternary copper complexes. Characterization of the compounds has been done using various techniques like elemental analyses, magnetic moments, conductance measurement, thermogravimetry and FT-IR, UV-Vis, 1H and 13C NMR, EPR and mass spectroscopy. The HL ligand acts as monoanionic O2N tridentate in most complexes, forming Cu(II) complexes with an octahedral and square planar geometrical arrangements. The compounds exhibit luminescence property; promising interesting potential applications as photoactive materials. The ground state (µg) and excited state (µe) dipole moments are estimated from solvatochromic shifts of absorption and fluorescence spectra as a function of the dielectric constant (Ɛ) and refractive index (n) by using Bilot–Kawski, Lippert–Mataga, Bakhshiev, Kawski–Chamma–Viallet and Reichardt correlation methods. Excited state dipole moment is observed as larger than the ground state dipole moment. The molecular structural parameters of the ligand and its Cu(II)- complexes have been calculated on the basis of DFT level implemented in the Gaussian 09 program at the B3LYP/6-31G(d,p) level and the theoretical data are correlated with the experimental data. The antibacterial properties of the ligand and its complexes have been screened against selected kinds of bacteria and fungi.

Novel complex of Ni(II) of ligand 2-(anilinoacetyl)-N-(3-methylphenyl)hydrazine-1- carbothioamide (H2L) has been synthesized and characterized by 1HNMR, IR, elemental analyses, molar conductance, UV-visible spectra, magnetic susceptibility measurements ,thermogravimetric analysis (TGA/DTG) and X-ray differaction pattern. The result confirmed that the ligand behaved as neutral bidentate, coordination take place via carbonyl oxygen(C=O) and N(2)H groups. Nickel complex is more thermally stable than free ligand . Nickel(II) complex is mononuclear, adopt square planar geometry . The ligand and complex have been tested for their inhibitory effect on the growth of bacteria against gram-positive (Streptococcus pyogenes) and gram-negative (Escherichia coli). The result revealed that Ni(II) complex showed a higher antibacterial activity against gram positive (Streptococcus pyogenes) and gram negative (Escherichia coli) bacteria than the ligand.

Objective: In modern years, the biggest dare is to develop new chemotherapeutic agents with high efficiency as well as low toxicity. Hence, to defeat this challenge, extensive endeavors were taken on thiosemicarbazone based metal complexes. Methods: A sequence of nine thiosemicarbazone based diimine copper(II) complexes derived from three sulfur-containing ligands N-methyl-2- ((1-methyl-1H-pyrrol-2-yl)methylene)hydrazinecarbothioamide H(L1), N-ethyl-2-((1-methyl-1H-pyrrol-2-yl)methylene)hydrazinecarbothioamide H(L2), and N-benzyl-2-((1-methyl-1H-pyrrol-2-yl)methylene)hydrazinecarbothioamide H(L3). The molecular structures and coordination possibilities of thiosemicarbazone ligands toward the central metal ions have been validated by analytical and spectral techniques such as molar conductance, elemental analysis, ultraviolet–Vis, Fourier-transform infrared, and electron paramagnetic resonance spectroscopy confirms that the thiosemicarbazones ligands are coordinated to copper through NS’ donor and NN’ donor of diimine. The antimicrobial activity and DNA cleavage effectiveness of thiosemicarbazone derivatives and copper(II) complexes were assessed by disc diffusion and agarose gel electrophoresis methods. Results: All the spectral studies authenticated that the square planar geometry of the thiosemicarbazone copper(II) complexes 1–9. From the results of antibacterial activity against selected Gram-positive (Bacillus thuringiensis) and Gram-negative (Escherichia coli) bacterial strains, complex 8 exhibited noteworthy activity. Interestingly, copper(II) complexes bearing 1,10-phenanthroline (phen) moiety displayed outstanding results together with N(4)-substituted thiosemicarbazone derivatives and causes complete DNA degradation of SC (supercoiled) pUC18 DNA. Conclusion: A variety of substitutions at the thioamide nitrogen atoms have shown potential biological activity. Henceforth, N(4)-substituted thiosemicarbazone based copper(II) complexes virtually reach the effectiveness of conventional chemotherapeutic drugs.

Eight new mixed ligand complexes of dioxomolybdenum(VI) with 2-hydroxy-3-methoxy/3,5-dibromo benzaldehyde 4-phenyl/ethyl-S-methyl/butyl thiosemicarbazones (L) were synthesized. The complexes of general formula [MoO2LD] (D: methanol, pyridine) were characterized by elemental analysis, IR, UV, and 1H-NMR spectroscopy. The structure of 3a was also determined by X-ray single-crystal diffraction. The thiosemicarbazone ligands are coordinated to dioxomolybdenum(VI) center through ONN set and the sixth coordinated site of the molybdenum is occupied by the second ligand (D). The in vitro antimicrobial activities of all thiosemicarbazones and their dioxomolybdenum(VI) complexes were tested against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Firat University Scientific Research Projects Management Unit: 27965 This work was supported by the Scientific Research Projects Coordination Unit of Istanbul University (Project Number: 27965).

Complexes [Zn(L2)2Cl2], [Pd2(L2)2Cl4], and CuL2Cl, where L2 is (−)-camphor thiosemicarbazone, were synthesized. The structures of complexes [Zn(L2)2Cl2] and [Pd2(L2)2Cl4] were determined by X-ray diffraction. The crystal structure of complex [Zn(L2)2Cl2] contains mononuclear molecules with distorted tetrahedral {ZnCl2S2} coordination units and monodentate L2 ligands. Complex [Pd2(L2)2Cl4] has binuclear structure with Pd metal centers linked by L2 ligands via μ2-S atoms. Complex CuL2Cl, according to IR and NMR spectra contains S and Cl atoms in the coordination sphere of ion Cu+. Complexes [Pd(tsc)Cl2] and Zn(tsc)2Cl2 (where tsc is thiosemicarbazide) were also obtained to determine the influence of the terpene moiety on cytotoxic properties of these compounds. Mononuclear complex [Pd(tsc)Cl2] contains an NSCl2 planar square coordination polyhedron, and tsc is a bidentate chelate ligand. The effects of tsc, L2, and the complexes with tsc and L2 on viability of the MCF-7 cell line were investigated next. The results showed that tsc and L2 are nontoxic at the tested concentrations (1–50 μM). All the complexes exerted a significant dose-dependent cytotoxic effect, whereas complex CuL2Cl was found to have the lowest half-maximal inhibitory concentration (IC50).

Complexes [In(2Ac4oFPh)Cl2(MeOH)] (1) and [In(2Ac4oFPh)Cl2]·0.5EtOH (2) were obtained with 2-acetylpyridine-N(4)-ortho-fluorophenyl thiosemicarbazone (H2Ac4oFPh). Neutron activation of 1 and 2 resulted in the formation of the 114mIn/115mIn analogues (*1) and (*2). The thiosemicarbazone ligand, the non-radioactive and radioactive complexes were assayed for their cytotoxic effects against U87 human glioblastoma cells. While radioactive and non-radioactive InCl3 were devoid of cytotoxic activity, complexes (1) and (2) and their radioactive analogues (*1) and (*2) showed similar cytotoxic effects and were as active as the parent thiosemicarbazone against U87 glioma cells. Since the radioactive complexes revealed to keep the thiosemicarbazone cytotoxicity, if these complexes are produced with high specific activity, they might constitute an interesting platform for the development of prototype radiotracer drugs for treatment of glioma neoplasia by delivering high radiation dose to the tumor cells.

Two series of new aromatic thiosemicarbazone derivatives were synthesized by condensation of N-(4-cyanophenyl)hydrazine carbothioamide (I) and N-(4-methylsulfanylphenyl)hydrazine carbothioamide (II) with appropriate aromatic aldehydes in order to investigate their antiviral and cytostatic potency. The chemical structures of all compounds were fully characterized by elemental analysis and spectroscopic techniques. The results of the bioassays indicated that compounds Id, Ie, If and IIf proved inhibitory against influenza virus A (EC50 = 13 - 27 μg/mL for strain H1N1 and 9.3 - 18 μg/mL for strain H3N2). Compounds Ig and IIg were the most cytostatic compounds with inhibition of HeLa cell proliferation at an IC50 = 0.3 μg/mL for Ig and 1.9 μg/mL for IIg. Especially, compound Ig showed the highest cytostatic activity with IC50 of 0.30, 0.70 and 2.50 μg/mL against HeLa, CEM and L1210 cell lines, respectively. This inhibition range was within the same order of magnitude as that for cisplatin. Furthermore, molecular modeling was carried out to examine the cytostatic activity and determine the best pharmacophore model as a guide for the design and development of potential prodrugs in future studies.

Neutral bivalent copper and nickel bis(thiosemicarbazone) complexes bearing the methoxy and bromine substituents on the dialdehyde-backbone of the ligand have been synthesized. All of them have been characterized by spectroscopic methods and in two cases by X-ray crystallography. Upon formation of these complexes, the each two bis(thiosemicarbazone) arms is deprotonated, acting as dianionic, tetradentate N2S2 ligands. The geometrical distortion from square planar in the copper complex is very greater than the nickel complex. Cyclic voltammetry studies of Cu(II) and Ni(II) complexes in DMF show that all complexes are able to stabilize low oxidation states of Cu(I) and Ni(I). The introduction of different substitutions on the aromatic ring attached to the imine carbon led to two consequences. First, The E1/2 values for the CuI/CuII and NiI/NiII redox couples were cathodically shifted in comparison with the unsubstituted analog. Second, the copper complexes underwent a quasi-reversible one-electron oxidation (CuII/CuIII).

Solvent-, acidity-, and redox-responsive thione(thiol)-disulfide interconversion were achieved by a dinuclear copper(ii) complex bearing a bis(thiosemicarbazone) (bTSC) ligand. The role of copper(ii) ion coordination was rationalized by parallel comparison with a bare bTSC ligand and zinc(ii) bTSC complexes under identical reaction conditions.

A series of six sulfur-bridged dinuclear silver(I) thiosemicarbazone complexes were synthesized through the reaction of silver(I) nitrate with 4-phenyl-3-thiosemicarbazone derivatives together with triphenylphosphine (PPh3) (in a 1:1:2 molar ratio). Following structural characterizations using various techniques such as elemental analysis, Fourier-transform infrared (FTIR) spectroscopy, as well as 1H, 13C, 31P{1H}s, COSY, and 1H-13C nuclear magnetic resonance (NMR) spectroscopy, it was found that the thiosemicarbazone ligand exists in the form of a thione rather than thiol tautomer. Subsequently, MDA-MB-231 and MCF-7 breast cancer cell lines, as well as the HT-29 colon cancer cell lines, were used to investigate the in vitro antiproliferative activities of these complexes. In all cases, the IC50 values were in the potent micromolar range. Besides, the aforementioned complexes also had good antiplasmodial activity against chloroquine-resistant P. falciparum, as per the results of histidine-rich protein 2 (HRP2) assays and cytotoxicity evaluations of MDBK cells.

A new complex of Zn(II) and 5-Bromosalicylaldehyde thiosemicarbazone (5-BSAT) has been studied. In solution, the 5-BSAT reacts with Zn(II) to form a complex with the maximum absorbance at 381 nm. Zn(II) ion forms a 1:1 stoichiometric complex. The stability constant is 4.21x105. Formation of the complex was completed within 20 min at pH 6.8 and VDMF = 2 mL. Beer’s law is obeyed over the range from 0.13 mg.L-1 to 0.39 mg.L-1 Zn(II) and the apparent molar absorptivity (e) is 1.08×104 L.mol−1.cm−1. The complex has been formulated and characterized by mass spectrometry, FT-IR, 1H-NMR and 13C-NMR spectroscopies and IQmol program. The molecular formula of the complex is C8H8O2N3SBrZn. The ligand coordinated as an ONS tridentate dianion through the oxygen atom of the deprotonated phenolic OH-group, the azomethine nitrogen atom and the sulfur atom after deprotonation of the thiosemicarbazide residue in its thiol form. Based on these results, the 5-BSAT reagent applied to determination of Zn2+ in waste water samples and the complex showed an effective antimicrobial activity.

The use of N,S chelating ligands such as thiosemicarbazides and dithiocarbazates provides an excellent environment to complex transition metals in a variety of oxidation states. Ligands of this sort initially prompted research in the medical field for their anti-cancer activity. However, it was later realised their ability to complex metals for use in other applications was far more extensive.Complexes of Cu(III) and Ni(III) are rare (compared to Cu(II) and Ni(II)) and are not often isolated as stable entities, but have been proposed as transient intermediates in some reactions. The general requirements for stabilising high oxidation states stem from the nature of the donor atoms, the degree of electron delocalisation, the size of the chelate rings, the use of electron donating groups and the formal charge on the ligand to balance the high charge of the metal ion.Combining the b-diketone acetylacetone with 2 equivalents of the relevant thiosemicarbazide or dithiocarbazate produces a tetradentate N2S2 ligand that is suitable for stabilising high oxidation states according to the above specifications. These two families, acetylacetone bis(thiosemicarbazone) and acetylacetone bis(dithiocarbazate) Schiff bases, were investigated here in complex with Cu and Ni.The Ni(II) coordination chemistry with the acetylacetone bis(thiosemicarbazone) ligands was studied and two linkage isomers were observed to form; a symmetric and an asymmetric species, in the absence of oxygen. Exposure to air led to the symmetric Ni(II) isomer undergoing ligand oxidation with a ketone group installed on the acetylacetone backbone. The explanation for this phenomenon was linked with the redox-activity of the ligand.The Cu(II) coordination chemistry found only symmetric coordination of the acetylacetone bis(thiosemicarbazone) ligands and again ligand oxidation to the ketone derivative was seen. In this case a Cu(II) intermediate (most likely bearing a ligand centred radical) was identified using a combination of spectroelectrochemistry, voltammetry and time-resolved UV-Vis spectroscopy.The findings were extended to investigating the copper and nickel complexes of the analogous benzoylacetone bis(thiosemicarbazones) to explore the mix of electron donating and electron withdrawing features on the acetylacetone moiety, along with the presence of a bulky substituent to see if this directed the coordination or reactivity of the complex.Finally, investigating acetylacetone bis(dithiocarbazate) Schiff base complexes of nickel and copper revealed a major effect upon exchanging the non-coordinating terminal nitrogen of a thiosemicarbazone with a sulfur of a dithiocarbazate. In this case, both Cu(III) and Ni(III) complexes were isolated and structurally characterised. This produced surprisingly significant differences that may be the key to understanding why high oxidation states are more often seen with ligands of acetylacetone bis(dithiocarbazate) Schiff bases than acetylacetone bis(thiosemicarbazones).

Herein, we report the synthesis of eight new mononuclear and binuclear Co2+, Ni2+, Cu2+, and Zn2+ methoxy thiosemicarbazone (MTSC) complexes aiming at obtaining thiosemicarbazone complex with potent biological activity. The structure of the MTSC ligand and its metal complexes was fully characterized by elemental analysis, spectroscopic techniques (NMR, FTIR, UV-Vis), molar conductivity, thermogravimetric analysis (TG), and thermal differential analysis (DrTGA). The spectral and analytical data revealed that the obtained thiosemicarbazone-metal complexes have octahedral geometry around the metal center, except for the Zn2+-thiosemicarbazone complexes, which showed a tetrahedral geometry. The antibacterial and antifungal activities of the MTSC ligand and its (Co2+, Ni2+, Cu2+, and Zn2+) metal complexes were also investigated. Interestingly, the antibacterial activity of MTSC- metal complexes against examined bacteria was higher than that of the MTSC alone, which indicates that metal complexation improved the antibacterial activity of the parent ligand. Among different metal complexes, the MTSC- mono- and binuclear Cu2+ complexes showed significant antibacterial activity against Bacillus subtilis and Proteus vulgaris, better than that of the standard gentamycin drug. The in silico molecular docking study has revealed that the MTSC ligand could be a potential inhibitor for the oxidoreductase protein.

New tetradentate phenolate O^N^N^S thiosemicarbazone (TSC) ligands and their Ni(II), Pd(II) and Pt(II) complexes were studied. The diamagnetic and square planar configured orange or red complexes show reversible reductive electrochemistry and in part reversible oxidative electrochemistry at very moderate potentials. DFT calculations show essentially pyridyl-imine centred lowest unoccupied molecular orbitals (LUMO) while the highest occupied molecular orbitals (HOMO) receive contributions from the phenolate moiety, the metal d orbitals and the TSC thiolate atom in keeping with UV-vis spectroelectrochemistry. DFT calculations in conjunction with IR spectra showed details of the molecular structures, the UV-vis absorptions were modelled through TD-DFT calculation with very high accuracy. UPS is fully consistent with UV-vis absorption and TD-DFT calculated data and shows decreasing HOMO–LUMO gaps along the series Pd > Pt > Ni.

Made available in DSpace on 2021-06-25T10:48:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This work deals with two new molecule-based materials, namely NiII-complexes of general formulae [Ni(L1)2] (Ni1) and [Ni(L2)2] (Ni2), where L1 = trans-cinnamaldehyde-N(4)-methyl thiosemicarbazone and L2 = trans-cinnamaldehyde-N(4)-ethyl thiosemicarbazone, as potential antitumor agents. Both compounds were characterized by elemental analysis, molar conductivity and spectroscopic techniques (FTIR and NMR). Their molecular structures were obtained by single-crystal X-ray diffraction analysis. Each one crystallizes in a monoclinic space group P 21/c, also the asymmetric unit comprises of one NiII ion located on an inversion centre and one anionic ligand, which acts as a κ2N,S-donor affording a five-membered metallaring. The compounds were screened against two selected tumour cell lines (MCF-7 and A549) and non-tumour fibroblasts cell line (MRC-5) via MTT assays. In both tumour cells, all compounds exhibited higher cytotoxicity than the control drug (cisplatin). The IC50 values ranges of 3.70 – 41.37 μM and 1.06 – 14.91 μM were found for MCF-7 and A549, respectively. Importantly, all of them were less toxicity than cisplatin in MRC-5 with SI values ranged at 11.80 – 86.60. The red blood cell (RBC) assay revealed Ni2 as non-toxic due to its reduced haemolytic effect (0‐–9% at 1‐–10 μM). The DNA binding was investigated through a combination of spectrophotometric absorption and emission titrations, electrophoresis, and circular dichroism experiments. As a result, these metal complexes were not able to strongly binding to DNA (Kb values ~104 mol L‐−1) but suggesting groove-binding interactions. The scavenging ability of them towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical was also evaluated in this work, but no important antioxidant behaviour was detected. Further, the interaction of Ni1 and Ni2 to human serum albumin (HSA) was explored by quenching of tryptophan emission, warfarin competitive assay, and molecular docking protocols. The HSA binding analyses indicated good affinity of both complexes to Sudlow site I (Kb values ⁓103 mol L−1). Univ. Estadual Paulista (Unesp) Instituto de Química Departamento de Química Analítica Físico-Química e Inorgânica Univ. Estadual de Londrina (UEL) Departamento de Química Univ. Estadual Paulista (Unesp) Instituto de Química Laboratório de Química Medicinal Síntese Orgânica e Modelagem Molecular (LaQMedSOMM) Technische Universität Dresden (TUD) Department of Chemistry and Food Chemistry Univ. Federal de São Carlos (UFSCar) Departamento de Química Univ. Federal de Sergipe (UFS) Departamento de Química Univ. de São Paulo (USP) Instituto de Física de São Carlos Univ. Estadual Paulista (Unesp) Faculdade de Ciências Farmacêuticas Univ. Estadual Paulista (Unesp) Instituto de Química Departamento de Bioquímica e Química Orgânica Univ. Federal do Rio Grande (FURG) Escola de Química e Alimentos Univ. Federal de Santa Maria (UFSM) Departamento de Química Univ. Estadual Paulista (Unesp) Instituto de Química Departamento de Química Analítica Físico-Química e Inorgânica Univ. Estadual Paulista (Unesp) Instituto de Química Laboratório de Química Medicinal Síntese Orgânica e Modelagem Molecular (LaQMedSOMM) Univ. Estadual Paulista (Unesp) Faculdade de Ciências Farmacêuticas Univ. Estadual Paulista (Unesp) Instituto de Química Departamento de Bioquímica e Química Orgânica CAPES: 001 FAPESP: 15/12098-0 FAPESP: 2016/17711-5 CNPq: 305190/2017-2 CNPq: 422105/2016-3

Two new polyoxometalate (POM)-based hybrid compounds modified by a Schiff base, [Fe(DAPSC)(H2 O)2 ]2 [HPMo2 V Mo10 VI O40 ] ⋅ 5H2 O (1) and [Fe(DAPSC)(H2 O)]2 [HPV3 IV Mo4 V Mo7 VI O42 ] ⋅ 6H2 O (2), (DAPSC=2,6-diacetylpyridine bis-(semicarbazone)), have been successfully constructed from typical Keggin POMs, iron ions, and DAPSC ligands under hydrothermal condition. Structural analysis demonstrates that the Fe-Schiff base ligand units are free from polyacid anions in compound 1. While in compound 2, the Fe-Schiff base ligand units are bridged with polyacid anions via Fe-O bonds to emerge a stable double-supported skeleton. Noticeably, owing to the introduction of vanadium in H5 PMo10 V2 O40 ⋅ 32.5H2 O, a divanadium-capped configuration is shaped in compound 2. Besides, the third-order nonlinear optical (NLO) properties of two compounds were explored. It should be noted that both compounds 1 and 2 have two-photon absorption properties, which indicates that the two compounds are potential nonlinear optical materials.

The present work reports the synthesis and structural elucidation of six novel copper(II) complexes with 2-acetylpyridine semicarbazone (HL1) and 2-acetylpyridine N(4)-phenyl semicarbazone (HL2). In all compounds, the semicarbazone ligands were find tridentate with NNO-donor atoms. The single crystal X-ray diffraction analysis showed the influences of the different copper salt starting reagent in the crystal structures. A packing architectures analysis has been undertaken to delineate the role of relevant noncovalent interactions. The π···π stacking interactions and hydrogen bonds were analyzed using the Hirshfeld surface and fingerprint plots. In addition, the compounds were also characterized by physicochemical and spectroscopic methods. A new ligand and six copper(II) complexes of semicarbazone derivatives have been synthesized and their crystal structures have been studied. Spectroscopy experiments and Hirshfeld Surface were analyzed.