Browsing by Author "A. Bharti"

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Ag(i), Cu(II), Co(III) and Hg(II) complexes and metal-assisted products derived from 4-methyl-piperidine-carbodithioate: Syntheses, structures, thermal analyses, redox behaviour and fluorescence properties
(Royal Society of Chemistry, 2016) Paras Nath; M.K. Bharty; B. Maiti; A. Bharti; R.J. Butcher; J.L. Wikaira; N.K. Singh
Four new complexes [Ag2(4-mpipdtc)2(PPh3)2] (1), [Cu(4-mpipdtc)2] (2), [Co(4-mpipdtc)3]·CHCl3 (3) and [PhHg(4-mpipdtc)] (4) and two new products, bis(4-methyl piperidinethiocarbonyl) disulfide {(4-mpipdtc)2} (5) and (4-methyl-piperidin-1-yl) carbothioylsulfanyl-methyl (4-methyl)-piperidine-1-carbodithioate {CH2(4-mpipdtc)2} (6) have been obtained in this study. The syntheses of compounds 5 and 6 were assisted by Mn(ii) and Ag(i) ions, respectively, and were obtained from potassium 4-methyl-piperidine-carbodithioate {K+(4-mpipdtc)-} {where, 4-mpipdtc- = 4-methyl piperidine carbodithioate}. All new compounds have been characterized by elemental analyses, IR, NMR, magnetic susceptibility and single X-ray crystallography techniques. These compounds are stabilized by intermolecular C-H⋯S, S⋯S, C-H⋯π and C-H⋯N interactions. The most interesting feature in complex 4 is that the ligand bound phenylmercury cation is stabilized via intermolecular as well as intramolecular Hg⋯S secondary interactions. Compounds 3 and 5 are highly fluorescent in a solution when compared to the free ligand and emit violet/violet-blue light at 372 and 413 nm upon excitation at 328 and 300 nm, respectively. The course of the thermal degradation of complexes 1-4 have been investigated by TG-DTA, which indicates that metal sulphide is formed as the final residue. The results obtained from the electronic structure calculations at the density functional theory level corroborate our experimental findings obtained from the IR data. Frontier molecular orbital analysis reveals that complexes 1 and 3 are softer and more reactive than complexes 2 and 4. Cyclic voltammetry shows that complex 2 exhibits a reversible Cu(ii)/Cu(i) redox process at 0.515 V, whereas the ligand and complexes 1, 3 and 4 show irreversible redox behaviour. © The Royal Society of Chemistry 2016.
Antiproliferative activity and electrochemical oxygen evolution by Ni(ii) complexes ofN′-(aroyl)-hydrazine carbodithioates
(Royal Society of Chemistry, 2021) R. Chaurasia; Shivendra Kumar Pandey; Devesh Kumar Singh; M.K. Bharty; Vellaichamy Ganesan; S.K. Hira; P.P. Manna; A. Bharti; Ray J. Butcher
The electrochemical water splitting by transition metal complexes is emerging very rapidly. The nickel complexes also play a very vital role in various biological activities. Here, three new ligands {H2mbhce =N′-(4-methyl-benzoyl), H2pchce =N′-(pyridine-carbonyl) and H2hbhce =N′-(2-hydroxy-benzoyl) hydrazine carbodithioic acid ethyl ester} and their corresponding Ni(ii) complexes [Ni(Hmbhce)2(py)2] (1), [Ni(pchce)(o-phen)2]·CH3OH·H2O (2) and [Ni(hbhce)(o-phen)2]·1.75CHCl3·H2O (3) have been synthesized and fully characterized by various physicochemical and X-ray crystallography techniques. The photoluminescence study and thermal degradations were also examined. The treatment of K562 cells with the increasing concentrations of the nickel salts, ligands, and complexes1,2, and3showed dose-dependent cytotoxicity. The cytotoxic activity of ligands reveals that ligand H2mbhce is more potent in inhibiting the growth of tumor cells in comparison to other ligands H2pbhce and H2hbhce. Cytotoxicity assay results indicate that all complexes have remarkable cytotoxic potential in comparison to either nickel salts or the free ligands. Among these complexes, complex1has significantly better anti-tumor activity as compared to complexes2and3. The electrochemical study of complexes1,2, and3for water oxidation reveals that all the complexes possess admirable electrocatalytic activity towards oxygen evolution reaction (OER) and have lower overpotential (328, 338, and 370 mV, respectively) than many previously reported complexes and RuO2(390 mV). Among complexes1,2, and3, complex-2shows a better water oxidation response. Consequently, these complexes have great potential to be utilized in fuel cells. The more reliable electrochemical parameter TOF is also calculated for all three complexes. © The Royal Society of Chemistry 2021.
Assessment of left ventricular diastolic dysfunction in sub-clinical hypothyroidism
(Avicena Publishing, 2012) C.L. Meena; R.D. Meena; R. Nawal; V.K. Meena; A. Bharti; L.P. Meena
Background: Adverse cardiovascular effect of hypothyroidism has been identified in many studies. Early identification of patients with sub-clinical hypothyroidism may lead to early treatment and thereby favourable effect on cardiovascular morbidity and mortality. Objectives: To find out the association of sub clinical hypothyroidism and left ventricular dysfunction and also to find out relationship between systolic and diastolic dysfunction in these patients. Material and Methods: A total 30 cases of sub clinical hypothyroidism along with 15 age sex matched healthy control subjects were included in study. Serum TSH, T4, T3 hormone level was measured and those who were found to have sub-clinical hypothyroidism underwent for 2DEcho. Results: Significant reduction in peak early filling velocity (PE) (p<0.001) and early filling time velocity integral (Ei) (p<0.001). Ratio of early and late peak velocities (PE/PA) (p<0.001), ratio of time velocity integral of early and atrial filling (Ei/Ai) (p<0.001) and ratio of the early peak to average velocity (PE/M) (p<0.001) were also reduced. Mean EF was 54.9± 5.55 as compared to 55.7 ± 3.46 of control subjects with a T. value of 0.48, however there was significant diastolic dysfunction in case of hypothyroid patients (mean Ei/Ai = 1.35 ± 0.53) as compared to control group subjects (mean Ei/AI = 2.11 ± 0.26) with a T value of 5.22. Conclusion: Sub-clinical hypothyroidism showed significant diastolic dysfunction in the absence of significant impairment of systolic function. © AVICENA 2012.
Cu(II), Zn(II) and Mn(II) complexes of NNS tridentate and Pd(II) complex of NN(μ-S) tetradentate thiobenzyl esters: Synthesis, spectral and X-ray characterization
(Elsevier Ltd, 2015) Pooja Bharati; A. Bharti; M.K. Bharty; N.K. Singh; S. Kashyap; Udai P. Singh; R.J. Butcher
A new type of NNS tridentate ligand, N′-[bis(benzylsulfanyl)methylene]-picolinoyl hydrazide (Hbsmph) (1), and N′-(pyridine 2-carbonyl) hydrazine carbodithioic acid benzyl ester (H2pchcbe), together with their Cu(II), Zn(II)/Mn(II) and tetranuclear Pd(II) complexes, have been synthesized. The reactions of N′-[bis(benzylsulfanyl)methylene]-picolinoyl hydrazide (Hbsmph) (1) with CuCl2·2H2O, CuBr2 and CuCl gave [Cu(bsmph)X·CH3OH] {X = Cl (2), Br (3)} and [Cu(bsmph)(μ-Cl)]2·2H2O (4), respectively. The reactions of N′-(pyridine 2-carbonyl) hydrazine carbodithioic acid benzyl ester (Hpchcbe) with ZnCl2·2H2O, MnCl2·4H2O and ZnBr2 yielded [M(Hpchcbe)2]·CHCl3 {M = Zn (5), Mn (7)} and [Zn(Hpchcbe)2] (6), which possess a distorted octahedral geometry. A tetranuclear [Pd4(μ-pchcbe)4]·4H2O complex (8) has also been prepared by the reaction of Hpchcbe with PdCl2, which has a square planar geometry around each Pd(II) centre. An interesting feature of the Pd(II) complex is the formation of an eight membered twisted boat-like arrangement of alternate palladium and sulfur atoms, with Pd-Pd distances of 3.317(5) and 3.280(5) Å. In [Pd4(μ-pchcbe)4]·4H2O, the ligand behaves as NN(μ-S) dinegative tetradentate, whereas in the Zn(II) and Mn(II) complexes it acts as mononegative NNS tridentate. The thermal degradation of complexes 4 and 8 has been investigated by TGA, which indicates that the final residues are CuS and PdS, respectively. © 2015 Elsevier Ltd. © 2015 Elsevier Ltd. All rights reserved.
Hg(II) complexes of 4-phenyl-5-(3-pyridyl)-1,2,4-triazole-3-thione and 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione and a Ni(II) complex of 5-(thiophen-2-yl)-1,3,4-oxadiazole-2-thione: Synthesis and X-ray structural studies
(Elsevier Ltd, 2013) A. Bharti; M.K. Bharty; S. Kashyap; U.P. Singh; R.J. Butcher; N.K. Singh
Three new mixed ligand complexes, [Hg(en)(4-pptt)2] (2) {4-pptt = 4-phenyl-5(3-pyridyl)-1,2,4-triazole-3-thione}, [Hg(en)(4-pot)2] (3) {4-pot = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione} and [Ni(en) 2(5-thot)2] (4) {5-thot = 5-(thiophen-2-yl)-1,3,4- oxadiazole-2-thione}, have been prepared containing en as a co-ligand. It is observed that 5-(pyridine-4-carbonyl) hydrazine carbodithioic acid methyl ester undergoes cyclization during complexation with Hg(II) in the presence of ethylenediamine and formed complex 3 containing 5-(4-pyridyl)-1,3,4-oxadiazole- 2-thione. The metal complexes have been characterized with the aid of elemental analyses, IR, magnetic susceptibility and single crystal X-ray studies. The ligand 4-pptt (1) and complexes 2, 3 and 4 crystallize in the monoclinic system, space group P21/n, P21/c, P121/c1 and P21/n respectively. The ligand is present in the deprotonated thiol form in complexes 2 and 3, and is bonded covalently through sulfur, while in complex 4 the ligand 5-(thiophen-2-yl)-1,3,4- oxadiazole-2-thione is present as the thione form and is bonded to Ni(II) through the oxadiazole nitrogen. Complex 4 shows quasi-reversible redox behavior assignable to a Ni2+/Ni3+ one electron transfer. The photoluminescence properties indicate that the complexes are fluorescent materials with maximum emissions at 433, 376 and 465 nm for complexes 2, 3 and 4 at excitation wavelengths of 293, 273 and 327 nm, respectively. All the complexes contain extended hydrogen bonding that provides a supramolecular framework. © 2012 Elsevier Ltd. All rights reserved.
Mononuclear Ag(I), dinuclear and polymeric Hg(II) complexes of 3-mercapto-4-methyl-4H-1,2,4-triazole: Syntheses, spectral, X-ray, photoluminescence and thermal analysis
(Elsevier Ltd, 2013) A. Bharti; P. Bharati; M.K. Bharty; R.K. Dani; Sanjay Singh; N.K. Singh
The reactions of AgNO3, PhHgOAc and HgCl2 with Hmmtrz gave three new complexes, [Ag(mmtrz)(PPh3)2] ·Hmmtrz (1), [Hg2(mmtrz)4(Hmmtrz)2] (2) and [Hg(mmtrz)2]n (3) (Hmmtrz = 3-mercapto-4-methyl-4H-1, 2,4-triazole), which have been isolated and well characterised by CHN analyses, IR, NMR, single crystal X-ray and TG-DTA data. Complex 1 adopts a distorted trigonal planar arrangement in which Ag(I) is bonded through the thiolato sulfur atom of the mmtrz anion and two phosphorus atoms of PPh3, along with one unit of the ligand held via a weak Ag⋯S contact. Complex 2 has been formed by symmetrization or dimerisation in chloroform solution via the reaction 4[PhHgL]-[Hg2L4] + 2HgPh2. In the dimeric complex 2, each Hg(II) centre has a distorted tetrahedral geometry bonded through two thiolato sulfur atoms of two terminal ligands, one nitrogen and one thiol sulfur (SH) from a neutral bridging ligand, forming an eight-membered ring around two Hg(II) centers. The one dimensional metal-organic coordination polymer of complex 3 is obtained by the reaction of HgCl2 with Hmmtrz in methanol, in which Hg(II) adopts a tetrahedral geometry bonded through two thiolato sulfur and two nitrogen atoms from two ligands. Complexes 1 and 2 are stabilized by intermolecular π⋯π interactions. Supramolecular organisation through hydrogen bonding is present in these complexes. Complexes 1 and 3 are fluorescent materials upon excitation at 263 and 327 nm respectively, exhibiting a weak emission at 389 nm and a medium-strong emission at 421 nm as a consequence of intraligand π-π transitions. The course of the thermal degradations of complexes 1 and 3 has been investigated by TG-DTA. Thermogravimetric analysis of complex 1 shows a single weight loss to give Ag2S, indicating that the complex might be useful as a precursor for the synthesis of pure Ag2S nanoparticles and thin films. © 2013 Elsevier Ltd. All rights reserved.
NNS tridentate thiosemicarbazide and 1,3,4-thiadiazole-2-amine complexes of some transition metal ions: Syntheses, structure and fluorescence properties
(Taylor and Francis Ltd., 2016) A. Bharti; Pooja Bharati; N.K. Singh; M.K. Bharty
The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded [Zn(ppts)2]·CHCl3 (3), [Mn(ppts)2]·THF (4), and [Ni(ppts)2]·THF (5), respectively, but HgCl2 gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H2SO4 formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but 3, 4 and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed [Zn(2-Hppt)2(OAc)2] (6) and [Cd2(2-Hppt)2(OAc)2(μ-OAc)2] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex 7 is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm. (Chemical Equation Presented). © 2016 Informa UK Limited, trading as Taylor & Francis Group.
Photophysical, electrochemical and TD-DFT studies of Ni(II) and Mn(II) complexes of N′-(2-methylfuran-3-carbonyl)hydrazine carbodithioic acid ethyl ester
(Elsevier Ltd, 2019) R. Chaurasia; M.K. Bharty; Paras Nath; Piyush Kumar Sonkar; Vellaichamy Ganesan; B. Maiti; A. Bharti; R.J. Butcher
Two new complexes [Ni(Hmfchce)2(py)2] (1) and [Mn(Hmfchce)2(o-phen)] (2) with [N′-(2-methylfuran-3-carbonyl)hydrazine]-carbodithioic acid ethyl ester (H2mfchce) have been synthesized which contain o-phenanthroline (o-phen)/pyridine (py) as coligand. The ligand and its metal complexes have been characterized by elemental analyses, IR, magnetic susceptibility and single crystal X-ray diffraction data. Complexes 1 and 2 crystallize in orthorhombhic system with space group ‘Pbca’ and ‘Pbcn’, respectively. In complex 1, nickel centre is coordinated through one hydrazine nitrogen atom, one carbonyl oxygen of two units of ligand and two pyridine nitrogen atoms. The manganese center in complex 2 is coordinated in a N4O2 core by two uininegative bidentate ligands using hydrazine nitrogen (after loss of proton) and carbonyl oxygen and two nitrogen atoms of o-phen. In both complexes, the metal ion adopts a distorted octahedral geometry. Complexes 1 and 2 are fluorescent materials which exhibit an emission at 291 and 285 nm, respectively upon excitation at 263 and 251 nm. The course of the thermal degradations of complexes 1 and 2 have been investigated by TGA which indicate that metal oxide is formed as the final residue in both complexes. The metal complexes, [Ni(Hmfchce)2(py)2] (1) and [Mn(Hmfchce)2(o-phen)] (2) were immobilized on glassy carbon electrodes using Nafion® (Nf). The modified electrodes have been characterized by cyclic voltammetry in 0.1 M KOH. Complexes 1 and 2 have efficient activity towards electrochemical water oxidation in the 0.1 M KOH. The simulated spectra of the two complexes 1 and 2 are characterized by excited states with ligand-to-ligand charge-transfer (LLCT) and ligand-to-metal charge-transfer (LMCT) character. © 2019 Elsevier Ltd
Search for anomalous fragments in 1.8A-GeV Ar40 reactions in nuclear emulsions
(1985) R. Bhanja; R. Joseph; S.K. Tuli; S.B. Beri; V.S. Bhatia; G. Kaur; M. Kaur; I.S. Mittra; K.B. Bhalla; A. Bharti; S. Lokanathan; S.K. Gupta; V.K. Gupta; G.L. Kaul; V. Kumar; L.K. Mangotra; Y. Prakash; N.K. Rao; S. Sankhydhar; S. Satti; G. Claesson; S. Garpman; N.Y. Herrström; B. Jakobsson; I. Lund; B. Norén; A. Oskarsson; I. Otterlund; S. Persson; M.M. Sherif; K. Söderström
Results are presented from an investigation of the mean free path in nuclear emulsion of multiply charged fragments, produced by 1.8A-GeV argon nuclei. Charge identification of 6965 fragments with charges Z2, producing 2192 secondary interactions, has been made. No dependence of the mean free path on the distance from the preceding collision is observed and thus our result is consistent with the nonexistence of anomalons. © 1985 The American Physical Society.
Search for anomalous interaction mean free paths of charge, 2≦Z≦18 projectile fragments in emulsions exposed to 1.8 A GeV40Ar ions
(Springer-Verlag, 1987) S.B. Beri; K.B. Bhalla; R. Bhanja; A. Bharti; V.S. Bhatia; G. Claesson; S. Garpman; S.K. Gupta; V.K. Gupta; N.Y. Herrstrom; B. Jakobsson; R. Joseph; G.L. Kaul; G. Kaur; M. Kaur; S. Kitroo; V. Kumar; S. Lokanathan; I. Lund; L.K. Mangotra; I.S. Mitra; S. Mookerjee; B. Norén; A. Oskarsson; I. Otterlund; Y. Prakash; S. Persson; N.K. Rao; S. Sankhyadhar; S. Satti; M.M. Sherif; K. Söderström; S.K. Tuli
40Ar-emulsion interactions are studied, to investigate the question of anomalons, in two G- 5 emulsion stacks. In about 4600 primary interactions, projectile fragments of Z≧2 for all generations have been followed until they interact or leave the stack. After careful estimation of charges of these fragments, variation of their mean free paths is studied as a function of distance from the preceding interaction. Generation effect, Nh dependence and production angle effect are investigated. In addition multi-chain events are analysed separately. Our results do not show anomalons at the 6% level and are consistent with non-occurrence of anomalons. However, this experiment is not sensitive enough to rule out anomalons (with a mfp of the order of 2 to 3 cm) produced at about 1% (or less) level. © 1987 Springer-Verlag.
Solvent-dependent crystallization and anti-cancer activities based on Ni(II) and Co(II) complexes of 1-picolinoyl-4-phenyl-3-thiosemicarbazide: Synthesis, crystal structure, and photoluminescence study
(Elsevier B.V., 2023) Suryansh Chandra; Shubham Jaiswal; Alok Shukla; Ankit Kumar Singh; Somenath Garai; A. Bharti; A. Acharya; M.K. Bharty
In search of alternative of platinum-based drugs for the treatment of cancer, lead to the development of other potential metallodrug of transition metal complexes. The efficacious and novel experimental content of this paper reports the synthesis of [Ni(Hppts)2].CHCl3 (1a), [Ni(Hppts)2].(CH3)2SO (1b) and [Co(Hppts)2] (2) complexes of 1-picolinoyl-4-phenyl-3-thiosemicarbazide (H2ppts). The synthesized complexes have been characterized by UV-vis., Infrared, and NMR spectrometry. Furthermore, complexes 1a and 1b were characterized by single-crystal X-ray diffraction data. Emission spectra show that, complex 1a exhibits higher fluorescence intensity as compared to that of ligand H2ppts and complex 2. The order of fluorescence intensity was found as complex 1a > complex 2 > H2ppts. Moreover, Complexes 1a and 1b are stabilized via various types of intermolecular interactions. The cytotoxicity of complexes 1a, 2, and ligand was evaluated against Dalton's Lymphoma cells using standard MTT Assay. The anticancer activity results showed that complex 1a significantly reduced cell viability in a dose-dependent manner, whereas H2ppts and complex 2 did not show significant reduction in cell viability of DL cells when compared with the control. The complex 1a IC50 value was determined to be around 40 µg/mL. The anti-tumor activity concludes that the complex 1a has high anti-neoplastic activity on DL cells at low doses. © 2023 Elsevier B.V.
Square planar Ni(II) complexes of pyridine-4-carbonyl-hydrazine carbodithioate, 1-phenyl-3-pyridin-2-yl-isothiourea and 4-(2-methoxyphenyl) piperazine-1-carbodithioate involving N-S bonding: An approach to DFT calculation and thermal studies
(Elsevier Ltd, 2013) P. Bharati; A. Bharti; M.K. Bharty; B. Maiti; R.J. Butcher; N.K. Singh
Three new complexes [H2en][Ni(pchc)2] (1) (pchc = pyridine-4-carbonyl-hydrazine carbodithioate), [Ni(Hppith)2] (2) (H2ppith = 1-phenyl-3-pyridin-2-yl-isothiourea) and [Ni(mppcdt) 2] (3) {mppcdt = 4-(2-methoxyphenyl)piperazine-1-carbodithioate} have been synthesized and characterized by elemental analyses, IR and single crystal X-ray diffraction data. The ligand H2ppith and complexes [H 2en][Ni(pchc)2] (1) [Ni(Hppith)2] (2) and [Ni(mppcdt)2] (3) crystallize in monoclinic, orthorhombic, monoclinic and triclinic system with space group P21/n, Icab, C2/c and P1, respectively. The nitrogen and sulfur donor sites of the bidentate ligands chelate Ni(II) forming two five-membered CSN2M chelate rings in the complex 1, two six membered C2SN2M rings in complex 2 and the sulfur donor sites of the bidentate ligand chelate Ni(II) forming two four membered CS2M rings in complex 3. The Ni(II) complexes are diamagnetic and have distorted square planar geometry. The crystal structure of the complexes are stabilized by various types of inter and intramolecular extended hydrogen bonding providing supramolecular framework. Results obtained from quantum chemical calculations at the density functional theory level corroborate our experimental findings from IR and UV. The course of the thermal degradation of complexes 1,2 and 3 has been investigated by TG-DTA. Thermogravimetric analyses of the complexes indicate NIO/NIS as the end residue. © 2013 Elsevier Ltd. All rights reserved.
Square planar Pd(II) complexes derived from 1-ethyl-3-phenylthiourea, 3-mercapto-4-methyl-1,2,4-triazole and 2-mercapto-5-methyl-1,3,4-thiadiazole: Syntheses, spectral, structural characterization and photoluminescence properties
(Elsevier S.A., 2016) P. Bharati; A. Bharti; P. Nath; S. Kumari; N.K. Singh; M.K. Bharty
The reaction of PdCl2 with 1-ethyl-3-phenyl-thiourea (Heptu), 3-mercapto-4-methyl-4H-1,2,4-triazole (Hmmtrz) and 2-mercapto-5-methyl-1,3,4-thiadiazole (Hmthd) respectively, yielded three new complexes [Pd(eptu)2] (1), [Pd(Hmmtrz)4]Cl2 (2) and [Pd(Hmthd)4]Cl2·2CHCl3 (3). These complexes have been isolated in pure form and characterized by elemental analyses, IR, NMR and single crystal X-ray diffraction technique. In all compounds the metal ion adopts a square-planar geometry. Two nitrogen and two sulfur atoms from the monoanionic eptu ligand in complex 1 are bonded to Pd(II) centre in trans fashion. Complexes 2 and 3 are salt-like and the metal centre is bonded through four neutral ligands. The electrical neutrality in these complexes is maintained by the presence of two chlorides as counter ions. Migration of hydrogen, within the ligand framework in complexes 2 and 3, from sulfur to nitrogen is observed that resulted in the thione form of the ligand and its coordination to the metal centre in both the complexes. Complex 2 is stabilized by intermolecular C-H⋯N and intramolecular N-H⋯Cl hydrogen bonding leading to an extended structure. Complex 3 is stabilized by intermolecular C-H⋯S hydrogen bonding. Complexes 1-3 are fluorescent materials which upon excitation at 31 000, 38 600 and 32 300 cm-1 exhibit an emission at 25 200, 27 000 and 26 700 cm-1, respectively. © 2016 Elsevier B.V. All rights reserved.
Studies on novel Cu(II) complexes of 5-(4-hydroxy-phenyl)-1,3,4- thiadiazole-2-thiol and 5-thiophen-2-yl-3H-1,3,4-oxadiazole-2-thione: Synthesis, spectral and structural characterization
(Elsevier Ltd, 2012) M.K. Bharty; A. Bharti; R.K. Dani; S.K. Kushawaha; R. Dulare; N.K. Singh
Two new mixed ligand complexes, [Cu(en)2](4-hpythol) 2·2H2O (4-hpythol = 5-(4-hydroxy-phenyl)-1,3,4- thiadiazole-2-thiol) (2) and [Cu(en)2(5-thot)2] (5-thot = 5-thiophen-2-yl-3H-1,3,4-oxadiazole-2-thione (3), have been prepared, containing en as the co-ligand. The starting ligands, potassium salts of thiohydrazide carbodithioate (RCSNHNHCSSK)/hydrazine carbodithioate (RCONHNHCSSK), underwent cyclization during the crystallization or complexation in the presence of ethylenediamine (en) and converted to 5-(4-hydroxy-phenyl)-1,3,4-thiadiazole-2- thiol and 5-thiophen-2-yl-3H-1,3,4-oxadiazole-2-thione, respectively. The metal complexes have been characterized with the aid of elemental analyses, IR, magnetic susceptibility and single crystal X-ray studies. The ligand 4-hpythol and complexes 2 and 3 crystallize in the triclinic and monoclinic systems, space group P 21/n, P1̄ and P 21/c, respectively. The ligand is present in the deprotonated thiol form in [Cu(en)2](4-hpythol)2· 2H2O (2), where it is ionically bonded through the thiol sulfur atom, while potassium N′-(thiophene-2-carbonyl) hydrazinecarbodithioate after cyclization is present as the thione form in [Cu(en)2(5-thot) 2] (3) and is covalently bonded through the N atom of the resulting oxadiazole-2-thione. The most noteworthy feature of 4-hpythol (1) is its existence in the thiol form in the solid state. Complex 3 show irreversible redox behavior, assignable to a M2+/M3+ one electron transfer. ESR signals were registered for complexes 2 and 3. Both complexes contain extended hydrogen bonding, providing supramolecular frameworks. © 2012 Elsevier Ltd. All rights reserved.
Studies on phenylmercury(II) complexes of nitrogen-sulfur ligands: Synthesis, spectral, structural characterization, TD-DFT and photoluminescent properties
(Elsevier Ltd, 2013) A. Bharti; P. Bharati; Ram Dulare; M.K. Bharty; Dheeraj K. Singh; N.K. Singh
The reactions of phenylmercury(II) acetate with N-phenyl-5-(pyridin-4-yl)- 1,3,4-thiadiazol-2-amine (Hppt) (1) and potassium N(4-methylpiperazine)-1- carbodithioate [K(mpcdt)] yielded [PhHg(ppt)] (2) and [PhHg(mpcdt)] (3). The complexes have been characterized by elemental analyses, IR, UV-Vis, 1H and 13C NMR spectroscopy. The ligand Hppt (1)- and complexes 2 and 3 crystallize in the triclinic, monoclinic and orthorhombic system, space group P1̄, C 2/c and Pbca, respectively. The crystal X-ray studies revealed that complexes 2 and 3 both form a one dimensional metal-organic structure, with a linear N-Hg-Ph and S-Hg-Ph core respectively. The most noteworthy features in complex 2 is that the ligand bound phenylmercury cation is stabilized via intramolecular as well as intermolecular weak Hgâ̄N secondary interactions. Crystal structure of complex 2 is also stabilized via weak πâ̄π and C-Hâ̄π interactions. The crystal structure of complex 3 is stabilized by intermolecular/ intramolecular Hgâ̄S interactions and C-Hâ̄π interactions. The ligands Hppt and [K(mpcdt)] exhibit green emissions and complex 2 shows photoluminescence due to the presence of Hgâ̄N interactions, whilst complex 3 does not show photoluminescence because Hgâ̄S interactions show quenching behaviour in the solid state. The solution state photoluminescence properties of complex 2 indicate that intermolecular as well as intramolecular Hgâ̄N interactions persist even in very dilute solution. The geometrical optimization of Hppt (1), [K(mpcdt)] and complexes 2 and 3 was calculated in the gas phase using density functional theory (DFT) with the B3LYP hybrid functional, and was used to predict their molecular properties. The electronic excitation energies and intensities of the six lowest-energy spin allowed transitions were calculated using time dependent density functional theory (TD-DFT). © 2013 Elsevier Ltd. All rights reserved.
Syntheses, crystal structures and photoluminescent properties of new homoleptic and heteroleptic zinc(II) dithiocarbamato complexes
(Elsevier Ltd, 2015) A. Bharti; Pooja Bharati; U.K. Chaudhari; A. Singh; S.K. Kushawaha; N.K. Singh; M.K. Bharty
Novel homoleptic dinuclear zinc(II) complex {[Zn2(μ-ppdtc)2(ppdtc)2] [Zn2(μ2-ppdtc)2(ppdtc)2]} (1) and three new heteroleptic complexes [Zn(ppdtc)2(bipy)] (2), [Zn(2-mppdtc)2(py)] (3) and [Zn(mpdtc)2(py)] (4) (ppdtc = phenyl piperazine dithiocarbamate, mppdtc = 2-methoxy phenyl piperazine dithiocarbamate and mpdtc = methyl piperazine dithiocarbamate) have been synthesized and characterized by elemental analyses, IR, 1H, 13C NMR and X-ray crystallography. Homoleptic complex {[Zn2(μ-ppdtc)2(ppdtc)2][Zn2(μ2-ppdtc)2(ppdtc)2]} (1) contains two different asymmetric units of [Zn2(μ-ppdtc)2(ppdtc)2] (B) and [Zn2(μ2-ppdtc)2(ppdtc)2] (A) in which each Zn(II) ion in one asymmetric dinuclear unit (B) possess tetrahedral geometry, whereas in other asymmetric dinuclear unit (A) both metal ions have five coordinate square pyramidal geometry. Complex [Zn(ppdtc)2(bipy)] (2) has an octahedral geometry, coordinated through two nitrogen atoms of the bipyridyl and four sulfur atoms of the two units of the dithiocarbamato ligands. Complexes [Zn(2-mppdtc)2(py)] (3) and [Zn(mpdtc)2(py)] (4) have distorted square pyramidal geometry, bonded through one pyridine nitrogen and four sulfur atoms of the two units of dithiocarbamato ligands. Complexes 1 and 2 are highly fluorescent in solution and emit light at 410 and 420 nm upon excitation at 330 and 360 nm wavelengths. © 2014 Elsevier Ltd. All rights reserved.
Syntheses, spectral and structural characterization of Ni(II) complexes of 4-amino-5-phenyl/3-pyridyl/thiophen-2H-1,2,4-triazole-3-thione
(2014) M.K. Bharty; Pooja Bharati; A. Bharti; A. Singh; Sanjay Singh; N.K. Singh
New mixed ligand complexes [Ni(aptt)2(en)2] (1), [Ni(apytt)2(en)2]×CHCl3 (2) and [Ni(athtt)2(en)2] (3) with 4-amino-5-phenyl-2H-1,2,4- triazole-3-thione (Haptt), 4-amino-5-(pyridin-3-yl)-4,5-dihydro-3H-1,2,4- triazole-3-thione (Hapytt) and 4-amino-5-thiophen-2H-1,2,4-triazole-3-thione (Hathtt) have been prepared containing en as the secondary ligand. The metal complexes have been characterized with the aid of elemental analyses, IR, magnetic susceptibility and single crystal X-ray data. All the complexes are bonded through two nitrogen atoms of two triazole ligands and four nitrogens of two ethylenediamine and the resulting complexes have distorted octahedral geometry. The triazole ligands behave as uninegative monodentate, bonding through triazole nitrogen due to the hard character of the nickel(II). The complexes contain extended hydrogen bonding providing supramolecular framework. The course of the thermal degradation of complex 2 has been investigated by TG-DTA which suggest the loss of CHCl3 molecule around 200 C and finally a residue of NiS is left behind. © 2013 Elsevier B.V. All rights reserved.
Syntheses, structural and thermal studies on Zn(II) complexes of 5-aryl-1,3,4-oxadiazole-2-thione and dithiocarbamates: Antibacterial activity and DFT calculations
(Elsevier Ltd, 2015) M.K. Bharty; R.K. Dani; P. Nath; A. Bharti; N.K. Singh; Om Prakash; Ranjan K. Singh; R.J. Butcher
The new complexes [Zn(pyot)2(en)2] (1), [Zn(mphot)2(en)2] (2), [Zn(bhpzdtc)2(py)] (3), [Zn(bhpzdtc)2(4-pic)] (4) and [Zn(ecpzdtc)(bpy)(Cl)] (5) {pyot = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione, mphot = 5-(4-methoxy phenyl)-1,3,4-oxadiazole-2-thione, bhpzdtc = 1-benzhydrylpiperazine dithiocarbamate, ecpzdtc = 1-ethoxycarbonyl piperazine dithiocarbamate} have been synthesized and characterized by various physicochemical techniques. Complexes 1 and 2 have been prepared from the potassium salt of N-aroylhydrazine carbodithioate (RCONHNHCSSK) which was cyclized into the corresponding 5-substituted-1,3,4-oxadiazole-2-thione during complexation in the presence of ethylenediamine (en), in which Zn(II) is bonded to the oxadiazole nitrogen atom. The potassium salts of substituted piperazine dithiocarbamates formed complexes 3-5, which contain pyridine/4-picoline/2,2′-bipyridyl as the co-ligand, and the zinc(II) center forms a four-membered CS2Zn ring with the dithiocarbamate ligand. The crystal structures of the complexes are stabilized by various types of inter and intramolecular hydrogen bonding, leading to supramolecular frameworks. Geometry optimization, geometrical parameters, molecular electrostatic potential maps (MEP) and FMO analyses of the complexes have been carried out by DFT methods, and these are presented and compared with the experimental X-ray diffraction data. The thermal decompositions of the complexes have been studied using thermogravimetric analysis (TGA) and the results show that complexes 1-2 and 3-5 form ZnO and ZnS, respectively, as the final residue. The bioefficacy of the complexes has been examined using the growth of bacteria to evaluate their anti-microbial potential. Complex 5 shows the highest antibacterial activity as compared to the other complexes. © 2015 Elsevier Ltd. All rights reserved.
Synthesis and characterization of Mn(II) complexes of 4-phenyl(phenyl-acetyl)-3-thiosemicarbazide, 4-amino-5-phenyl-1,2,4-triazole-3-thiolate, and their application towards electrochemical oxygen reduction reaction
(Elsevier Ltd, 2019) M.K. Bharty; A. Bharti; R. Chaurasia; U.K. Chaudhari; S.K. Kushawaha; P.K. Sonkar; V. Ganesan; R.J. Butcher
Two new complexes, [Mn(ppt)2(o-phen)] (1) and [Mn(aptt)(Cl)(o-phen)2]·2Haptt·H2O (2) with 4-phenyl (phenyl-acetyl)-3-thiosemicarbazide (Hppt) and 4-amino-5-phenyl-1,2,4-triazole-3-thiolate (Haptt) have been synthesized containing o-phenanthroline (o-phen) as a coligand. These complexes have been characterized by elemental analyses, IR and UV–Vis spectroscopic techniques, thermogravimetric analysis (TGA), magnetic susceptibility and single crystal X-ray diffraction data. The complexes are paramagnetic and have a distorted octahedral geometry. In complex 2, two molecules of Haptt and one water molecule are cocrystalized outside the coordination sphere. Complexes 1 and 2 are fluorescent and upon their excitation at 38 167 cm−1, exhibit emissions at 27 173 and 32 894 cm−1, respectively. TGA of complexes 1 and 2 indicate that the metal is converted into metal oxide at very high temperature. In the solid state, the crystal structure of both complexes are stabilized by various inter and intramolecular interactions. To explore the possible electrochemical applications of the complexes 1 and 2, they are immobilized on glassy carbon electrode using Nafion®. Cyclic voltammetry technique is used to characterize the metal complex immobilized electrodes in basic medium. Both complexes demonstrate excellent electrocatalytic activity towards electrochemical oxygen reduction. Since the electrocatalytic materials for oxygen reduction can dramatically increase the efficiency of the fuel cells and metal-air batteries, these metal complexes can be used as cathodic catalyst material in fuel cells and in metal-air batteries. © 2019 Elsevier Ltd
Synthesis and X-ray structural studies of Cd(II) and Ni(II) complexes of 5-(4-methoxy phenyl), 5-(2-pyridyl) and 5-(2-methoxy phenyl)-1,3,4-oxadiazole-2- thione
(2012) M.K. Bharty; A. Bharti; R.K. Dani; R. Dulare; P. Bharati; N.K. Singh
Three new mixed ligand complexes [Cd(en) 2(4-mpot) 2] (1) [Ni(2-pytone) 2(en) 2] (2) and [Ni(2-mpot) 2(en) 2] (3) {4-mpot = 5-(4-methoxy-phenyl)-1,3,4- oxadiazole-2-thione, 2-pytone = 5-(2-pyridyl)-1,3,4-oxadiazole-2-thione, 2-mpot = 5-(2-methoxy-phenyl)-1,3,4-oxadiazole-2-thione} have been prepared containing en as co-ligand. Potassium N-(4-methoxy benzoyl)-hydrazinecarbodithioate cyclized to 5-(4-methoxy-phenyl)-1,3,4-oxadiazole-2-thiol on addition of tetrabutylammonium bromide which then reacted with Cd(OAc) 2· 2H 2O and ethylenediamine to form complex 1, whereas potassium N-(2-methoxy benzoyl/pyridine-2-carbonyl)-hydrazinecarbodithioates (RCONHNHCSSK) underwent cyclization during complexation in the presence of en to give the complexes of the corresponding 5-aryl-1,3,4-oxadiazole-2-thiones. The complexes have been characterized by physicochemical techniques and single crystal X-ray structure determination. In the complexes the metal center has a six coordinate octahedral arrangement coordinated by 4N atoms of two en and two covalently bonded N atoms of the oxadiazole-2-thione anions. All the complexes contain extended hydrogen bonding providing supramolecular framework. © 2011 Elsevier B.V. All rights reserved.