Sesto Fiorentino, Italy
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Sathiyaraj E.,Kalasalingam University | Tamilvanan S.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Polyhedron | Year: 2017

Bis(N-furfuryl-N-substituted benzyldithiocarbamato-S,S′)zinc(II) (1–4) [substituted benzyl = 4F–C6H4–CH2– (1), 4Cl–C6H4–CH2– (2), 4OH–C6H4–CH2– (3), 4OCH3–C6H4–CH2– (4)] complexes were prepared and characterized by elemental analysis, IR and NMR (1H and 13C) spectroscopy. Structures of complex 2 and 4 were determined by single crystal X-ray crystallography. X-ray crystal structure of 2 revealed that the complex is dimeric and the geometry of this coordination polyhedron [ZnS5] is intermediate between tetragonal pyramid and trigonal bipyramid. The structure of 4 features, in contrast to 2, mononuclear species and the coordination geometry for the zinc atom is a highly distorted tetrahedron. The energy gap between the HOMO and LUMO in dimer 2 is lower than those of monomers (2 and 4). This indicates that the monomers are more stable than dimer. In vitro cytotoxic activity of the complexes 1–4 was evaluated on KB cell line. Complex 1 showed better cytotoxic activity than other complexes. These complexes were also screened for in vitro antibacterial and antifungal activities. Complexes 2 and 4 have been used as single source precursors for the preparation of ZnS nanoparticles. As-prepared ZnS nanoparticles were characterized using PXRD, TEM, UV–Vis and photoluminescence spectroscopy. TEM images show that spherical and rod nanoparticles were obtained from complexes 2 and 4, respectively. The photocatalytic activities of the as-prepared ZnS nanoparticles were evaluated by degradation of rhodamine B in aqueous solution under UV irradiation. © 2017 Elsevier Ltd


Gurumoorthy G.,Annamalai University | Rani P.J.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Inorganica Chimica Acta | Year: 2017

Five homoleptic complexes of general formula [Co(S2CNRR′)3] [where R = furfuryl; R′ = cyclohexyl (1), benzyl (2), furfuryl (3), methylferrocenyl (4), 2-phenylethyl (5)] were prepared and studied by FT-IR, UV–vis and NMR (1H and 13C) spectroscopy. A single crystal X-ray structural analysis was carried out for complex 3. Electronic spectral studies suggest octahedral geometry for all the complexes. In the molecular structure of 3, cobalt atom coordinates to three N,N-difurfuryldithiocarbamate ligands in the S,S′-bidentate mode, forming an octahedral polygon [CoS6]. DFT calculations were carried out for 3. The ability of complex 4 containing redox-active ferrocene moiety to sense anions (benzoate, F−, Br− and I−) was examined by cyclic voltammetric titration studies. This study reveals that complex 4 prefer to bind with Br− Complexes 3, 4 and 5 were utilized for the preparation of cobalt sulfide (3 and 5) and cobalt-iron sulfide (4) nanoparticles. The as-prepared nanoparticles were characterized by PXRD, TEM, EDS, UV–vis and FT-IR spectroscopy. TEM image of cobalt-iron sulfide nanoparticles reveals that the particles are cuboid. The blue shift in the absorption maxima in the UV–vis spectra of cobalt sulfide and cobalt-iron sulfide is attributed to the consequence of the quantum confinement effect. Photocatalytic activities of as-prepared nanoparticles were studied by decolourization of methylene green and rhodamine-B under ultraviolet light. It was found that the cobalt-iron sulfide degrades methylene green and rhodamine-B much faster than cobalt sulfide. © 2016 Elsevier B.V.


Tamilvanan S.,Annamalai University | Gurumoorthy G.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Polyhedron | Year: 2017

Bismuth(III) dithiocarbamate complexes, tris(N-furfuryl-N-propyldithiocarbamato-S,S')bismuth(III) (1), tris(N-furfuryl-N-butyldithiocarbamato-S,S')bismuth(III) (2) and tris(N-furfuryl-N-benzyldithiocarbamato-S,S')bismuth(III) (3), have been prepared and characterized by microanalysis, and spectroscopy (IR and NMR). Structure of 3 has been obtained by single crystal X-ray diffraction. This complex contains distorted pentagonal pyramidal Bi(III) centres which attain an overall distorted pentagonal bipyramidal coordination via long range intermolecular Bi⋯S interactions. DFT quantum mechanical studies of 3 were carried out, supporting the partial double bond character of C–N (thioureide) and C–S bonds in dithiocarbamate ligands. All the compounds have been screened against a panel of microbes viz. Vibrio cholerae, Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Aspergillus niger and Candida albicans. Complexes 1 and 3 were found to have better activity against K. pneumoniae, V. cholerae, A. niger and C. albicans than the complex 2. Complexes 1–3 have been evaluated for their in vitro cytotoxic activity against KB cells. Complexes 1 and 3 showed higher activity than 2. Bi2O3 obtained from thermal decomposition of 3 has been characterized by PXRD, HRTEM, EDAX, UV–Vis and Fluorescence spectroscopy. PXRD study showed that the sample is composed of monoclinic phase of α-Bi2O3. Photocatalytic activity of as-prepared α-Bi2O3 was determined by decolourization of rhodamine-B in aqueous solution under ultra violet irradiation. © 2016 Elsevier Ltd


Srinivasan N.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

(2,2′-Bipyridine)bis(1,2,3,4-tetrahydroquinolinecarbodithioato-S, S′)zinc(II), [Zn(thqdtc)2(2,2′-bipy)] (1) has been synthesized from bis(1,2,3,4-tetrahydroquinolinecarbodithioato-S,S′) zinc(II), [Zn(thqdtc)2] (2) and characterized by elemental analysis, IR and NMR spectroscopy and single crystal X-ray analysis. In the 13C NMR spectrum, complex 1 showed a single low-field resonance associated with back bone carbon of dithiocarbamate (N13CS2) at 209.2 ppm. Single crystal X-ray analysis of 1 showed that the zinc ion is in a distorted octahedral environment of two nitrogen atoms and four sulfur atoms around it. The complex 1 has been used as single source precursor for the preparation of ZnS nanosheets via solvothermal method. The ZnS nanosheets have been characterized by powder XRD, EDAX, TEM, UV-Vis and fluorescence spectroscopy. TEM studies indicate that the nanosheets are very thin. The nanosheets obtained show quantum size effect in their UV-Vis absorption spectrum. The strong emission peak centered at 415 nm in fluorescence spectrum could be attributed to the electron-hole recombination from internal vacancies for Zn and S atoms. © 2012 Elsevier B.V. All rights reserved.


Srinivasan N.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Journal of Molecular Structure | Year: 2014

(1,10-phenanthroline)bis(1,2,3,4-tetrahydroquinolinecarbodithioato-S,S′)mercury(II); [Hg(thqdtc)2(1,10-phen)] (1); has been synthesized and characterized by elemental analysis, IR and NMR spectroscopy and single crystal X-ray analysis. IR spectrum of the complex reveals the contribution of thioureide form to the structure. In the 13C NMR spectrum, [Hg(thqdtc)2(1,10-phen)] shows a single low-field resonance associated with backbone carbon of dithiocarbamate (N13CS2) at 205.7 ppm. The mononuclear structure of [Hg(thqdtc)2(1,10-phen)] exhibits monodentate and bidentate coordination by dithiocarbamate ligands and an intermediate geometry between tetragonal pyramidal and trigonal bipyramidal for mercury, defined by an N2S3donor set. [Hg(thqdtc)2(1,10-phen)] has been found to be an effective single-source precursor for the preparation of α-HgS nanosheets via solvothermal method. The as-prepared HgS nanosheets have been characterized by powder XRD, TEM, UV-Vis and fluorescence spectroscopy. TEM image of HgS exhibits that the as-prepared HgS particles are hexagonal shaped nanosheets. UV-Vis spectroscopy established pronounced quantum confinement effect. © 2014 Elsevier B.V. All rights reserved.


Valarmathi P.,Annamalai University | Thirumaran S.,Annamalai University | Ragi P.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Journal of Coordination Chemistry | Year: 2011

[M(4-epzdtc) 2(py)], [M(4-epzdtc) 2(1,10-phen)], and [M(4-epzdtc) 2(2,2″-bipy)] (where M=Zn(II), Cd(II); 4-epzdtc -=4-ethylpiperazinecarbodithioate) were synthesized and characterized by IR and NMR ( 1H, 13C, HSQC and HMBC) spectra. A single-crystal X-ray analysis was carried out for [Zn(4-epzdtc) 2(py)]. The N 13CS 2 chemical shifts of [M(4-epzdtc) 2] and its adducts follow the order: [M(4-epzdtc) 2] (ca 202 ppm)5[M(4-epzdtc) 2(py)] (ca 204 ppm)< [M(4-epzdtc) 2(N,N)] (N,N=1,10-phen, 2,2″-bipy) (ca 206 ppm), due to the change in coordination number. Single-crystal X-ray structural analysis of [Zn(4-epzdtc) 2(py)] showed that zinc is five-coordinate with four sulfurs from dithiocarbamate and one nitrogen from pyridine. This complex adopts a geometry intermediate between the tetragonal pyramid (C 4v) and trigonal bipyramid (D 3h). [Cd(4-epzdtc) 2] and its adducts were used as single source precursors for preparation of CdS. The as-prepared CdS was characterized by powder X-ray diffraction, UV-Vis absorption, and fluorescence spectroscopy. The UV-Vis absorption spectra of CdS particles indicate a blue shift in the absorption spectra due to the quantum size effect. © 2011 Taylor & Francis.


Srinivasan N.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Journal of Molecular Structure | Year: 2012

[Cd(thqdtc) 2(1,10-phen)] (1) and [Cd(thqdtc) 2(2, 2′-bipy)] (2) (where thqdtc = 1,2,3,4-tetrahydroquinolinedithiocarbamate, 1,10-phen = 1,10-phenanthroline and 2,2′-bipy = 2,2′-bipyridine) have been synthesized from [Cd(thqdtc) 2] (3). The downfield shift of N 13CS 2 carbon signal for 1 (209.8 ppm) and 2 (209.7 ppm) from the chemical shift value of 3 (208.2 ppm) is attributed to the increase in coordination number. Single crystal X-ray structures of 1 and 2 indicate that the central metal atom is in distorted octahedral environment for both complexes. The presence of added neutral ligand in the coordination sphere of 3 increases Cd-S distances in 1 and 2. S-Cd-S angles are not affected. The complex 1 has been used as precursor for the preparation of CdS nanoparticles. The CdS nanoparticles have been characterized by powder XRD, TEM and UV-vis spectroscopy. The quantum-confined CdS nanorods with diameter of ca. 7 nm and length ranging from 50 to 75 nm have been grown from 1 with diethylenetriamine. © 2012 Elsevier B.V. All rights reserved.


Gomathi G.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Polyhedron | Year: 2015

Two new homoleptic complexes, [Tl(bzfdtc)]2 (1) and [Tl(bu2-OHbzdtc)]2 (2) (where bzfdtc = N-benzyl-N-furfuryldithiocarbamate and bu2-OHbzdtc = (N-butyl-N-(2-hydroxybenzyl)dithiocarbamate), have been prepared and characterized by IR, NMR (1H and 13C), UV-Vis spectroscopy, cyclic voltammetry and single crystal X-ray structural analysis. X-ray crystallography revealed that both complexes are dimers. Both complexes show two monohapta Tl⋯C(S2) interactions. The Tl⋯Tl distances are 3.635 and 3.719 Å for 1 and 2, respectively. The phenyl ring of the bzfdtc ligand is coordinated (by a η6 interaction) to the Tl+ ion in complex 1. A rare intramolecular anagostic C-H⋯Tl interaction is observed in complex 2. Thallium sulfide nanoparticle samples 3 and 4 have been prepared from complex 1 using conventional heating and microwave irradiation, respectively. Samples 3 and 4 have been characterized by PXRD, EDAX, HR-TEM, UV-Vis absorption and fluorescence spectroscopy. PXRD measurements revealed rhombohedral and hexagonal phases for samples 3 and 4, respectively. EDAX confirmed the formation of Tl2S. HR-TEM images showed that the size and morphology of the Tl2S nanoparticles are affected by the method of preparation (conventional heating compared to microwave irradiation). © 2015 Elsevier Ltd. All rights reserved.


Srinivasan N.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
RSC Advances | Year: 2014

[Hg(thqdtc)2] (1) and [Hg(thqdtc)2(2,2′-bipy)] (2) (where thqdtc = 1,2,3,4-tetrahydrquinolinecarbodithioate and 2,2′-bipy = 2,2′-bipyridine) have been prepared and characterized. Single crystal X-ray structural analysis show that [Hg(thqdtc)2]·0.5(2, 2′-bipy) (3), [Hg(thqdtc)2]·0.25C2H 5OH (4) and [Hg3(thqdtc)6]·py (5) exist as monomer, dimer and trimer, respectively. Co-crystallization of 2,2′-bipyridine, ethanol and pyridine (py) with [Hg(thqdtc)2] causes a change in secondary interactions and hence, different structural motifs are obtained. Complexes 1 and 2 have been used as single source precursors for the preparation of HgS nanoparticles. The nanoparticles have been characterized by XRD, TEM, UV and fluorescence spectra. Use of 1 for the preparation of mercury sulfide afforded hexagonal shape HgS nanosheets and three different morphology HgS nanoparticles are obtained from 2; most of the crystallites are rod while the remainders are hexagonal and rectangle sheets. © 2014 the Partner Organisations.


Rani P.J.,Annamalai University | Thirumaran S.,Annamalai University | Ciattini S.,Centro Of Cristallografia Strutturale
Phosphorus, Sulfur and Silicon and the Related Elements | Year: 2013

Six new nickel complexes of two dithiocarbamate ligands (cyfdtc = N-cyclohexyl-N- furfuryldithiocarbamate and bztpedtc = N-benzyl-N-[2- thiophenylethyl]dithiocarbamate) namely, (Ni[cyfdtc]2) (1), (Ni[bztpedtc]2) (2), (Ni[cyfdtc][NCS][PPh3]) (3), (Ni[bztpedtc] [NCS][PPh3]) (4), (Ni[cyfdtc][PPh3]2)ClO4 (5), and (Ni[bztpedtc][PPh3]2)ClO4 (6) have been prepared and characterized using IR, electronic, and NMR (1H and 13C) spectra. A single crystal X-ray structural analysis was carried out for complex 3 and showed that nickel is in a distorted square planar arrangement with the NiS2PN chromophore. The shift in νCN of the heteroleptic complexes to higher frequencies compared with the parent complex is assigned to mesomeric delocalization of electron density from the dithiocarbamate ligand toward the metal atom, which increases the contribution of polar thioureide form in mixed ligand complexes. Electronic spectral studies suggest square planar geometry for the complexes. In the 13C NMR spectra, the upfield shift of NCS2 carbon signal for 3 and 4 from the chemical shift value of 1 and 2 is due to effect of PPh3 on the mesomeric drift of electron density toward nickel throughout thioureide CN bond. © 2013 Taylor and Francis Group, LLC.

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