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Tarlok S. Lobana

Bio: Tarlok S. Lobana is an academic researcher from Guru Nanak Dev University. The author has contributed to research in topics: Copper & Crystal structure. The author has an hindex of 32, co-authored 177 publications receiving 3786 citations. Previous affiliations of Tarlok S. Lobana include Chung Yuan Christian University & University of Santiago de Compostela.


Papers
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Journal ArticleDOI
TL;DR: In this article, the coordination chemistry of thiosemicarbazones and all the metals for which complexes are reported are discussed with respect to their bonding and structures, variable bonding properties, metallation, metal-metal interactions, role of solvents/other factors in stabilization of sulfur-bridging in coinage metals, and the nature of substituents at azomethine carbon.

526 citations

Journal ArticleDOI
02 Jan 2003-Talanta
TL;DR: A new ion-selective PVC membrane electrode based on salicylaldehyde thiosemicarbazone as an ionophore is developed successfully as sensor for mercury(II) ions and shows excellent potentiometric response characteristics.

126 citations

Journal ArticleDOI
TL;DR: Ab initio density functional theory calculations on model monomeric and dimeric complexes of the simplest thiosemicarbazone have revealed that monomers and halogen-bridged dimers have similar stability and that sulfur-bridges dimers are stable only when halogen atoms are engaged in hydrogen bonding with the solvent of crystallization or H2O molecules.
Abstract: Reactions of copper(I) halides with a series of thiosemicarbazone ligands (Htsc) in the presence of triphenylphosphine (Ph3P) in acetonitrile have yielded three types of complexes: (i) monomers, [CuX(η1-S-Htsc)(Ph3P)2] [X, Htsc = I (1), Br (2), benzaldehyde thiosemicarbazone (Hbtsc); I (5), Br (6), Cl (7), pyridine-2-carbaldehyde thiosemicarbazone (Hpytsc)], (ii) halogen-bridged dimers, [Cu2(μ2-X)2(η1-S-Htsc)2(Ph3P)2] [X, Htsc = Br (3), Hbtsc; I (8), furan-2-carbaldehyde thiosemicarbazone (Hftsc); I (11), thiophene-2-carbaldehyde thiosemicarbazone (Httsc)], and (iii) sulfur-bridged dimers, [Cu2X2(μ2-S-Htsc)2(Ph3P)2] [X, Htsc = Cl (4), Hbtsc; Br (9), Cl (10), pyrrole-2-carbaldehyde thiosemicarbazone (Hptsc); Br (12), Httsc]. All of these complexes have been characterized with the help of elemental analysis, IR, 1H, 13C, or 31P NMR spectroscopy, and X-ray crystallography (1−12). In all of the complexes, thiosemicarbazones are acting as neutral S-donor ligands in η1-S or μ2-S bonding modes. The Cu···Cu sepa...

124 citations

Journal ArticleDOI
TL;DR: In this article, the reaction of phenylmercury(II) acetate with a series of alkyl, aryl and heterocyclic thiosemicarbazones in ethanol formed novel phenylmerscury derivatives of stoichiometry, characterised with the help of analytical data, physical properties, IR, far-IR, multinuclear NMR (1H, 13C, 199Hg) spectroscopy and X-ray crystallography of complexes 1, 5 and 6.
Abstract: The reactions of phenylmercury(II) acetate with a series of alkyl, aryl and heterocyclic thiosemicarbazones in ethanol formed novel phenylmercury(II) derivatives of stoichiometry [HgPhL] [HL = RN3N2HC1(S)N1H2 = cyclopentanone 1, cyclohexanone 2, benzaldehyde 3, 2-hydroxybenzaldehyde 4, 4-methoxybenzaldehyde 5, pyrrole-2-carbaldehyde 6, thiophene-2-carbaldehyde 7 or furan-2-carbaldehyde 8 thiosemicarbazone], characterised with the help of analytical data, physical properties, IR, far-IR, multinuclear NMR (1H, 13C, 199Hg) spectroscopy and X-ray crystallography of complexes 1, 5 and 6. The 1H and 13C NMR data suggest that the N2H group is deprotonated during reaction with phenylmercury(II) acetate and co-ordination occurs via the N3,S atoms in a chelating mode. The 199Hg NMR data suggest symmetrisation phenomenon for complexes 3 and 5, 2[HgPhL] ⇌ HgPh2 + [HgL], which is supported also by 1H and 13C NMR data. The δ(Hg) values reveal that shielding of Hg with the change of organic group in the thiosemicarbazones decreases in the order: 2-hydroxybenzene ⋙ furan > benzene > 4-methoxybenzene thiophene ≈ cyclohexanone ≈ cyclopentanone > pyrrole and the Lewis basicity of the thiosemicarbazones varies in the opposite order. The 1H and 13C NMR data reveal that 7 and 8 show isomerism. There are two strong [Hg–C 2.063(7) 1, 2.069(10) 5, 2.049(11) 6; Hg–S 2.382(2) 1, 2.357(3) 5, 2.377(3) A 6] and one weak bond [Hg–N3 2.489(6) 1, 2.611(7) 5, 2.492(9) A 6], with CPh–Hg–S bond angles of 162.9(2), 174.2(3), 165.8(3)° respectively. The weak intermolecular interactions via Hg · · · N2 [3.001(6) A] in 1 and via Hg · · · S in 5 [3.518(3) A] and 6 [3.528(3) A] form centrosymmetric dimers and Hg formally acquires four-co-ordination with two strong (Hg–C, Hg–S), one weak (Hg · · · N3) and one secondary (Hg · · · N2 or S) bonds. The preferred dimer formation via N2 nitrogen in 1, rather than via sulfur atoms (5 and 6) despite Hg · · · S affinity represents an unusual bonding mode. From the low-temperature 1H NMR studies of some selected complexes, the energy barrier (ΔGTc*, Tc is coalescence temperature) to rotation of the amino group about the C1–N1 bond was calculated and correlated with bonding parameters of the thioamide group in the solid state.

101 citations

Journal ArticleDOI
TL;DR: In this article, a review of the coordination chemistry of selenium containing ligands is presented, including diselenophosphates and triselenophophosphonates with functional groups.

91 citations


Cited by
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Journal ArticleDOI
30 May 1953-Nature
TL;DR: The International Tables for X-ray Crystallography (ITC) as mentioned in this paper were published by the International Union of Crystallographers (IUC) for the first time in 1952.
Abstract: International Tables for X-Ray Crystallography (Published for the International Union of Crystallography.) Vol. 1: Symmetry Groups. Edited by Norman F. M. Henry and Kathleen Lonsdale. Pp. xi + 558. (Birmingham: Kynoch Press, 1952.) 105s.

691 citations

Journal ArticleDOI
TL;DR: The structural aspects of the complexes formed by thiosemicarbazones and semicarazones (TSCs) with the metallic elements of Groups 12, 13, 14 and 15 are surveyed up to 1998.

629 citations

Journal ArticleDOI
TL;DR: This critical review provides an overview of the developing knowledge, in the context of supramolecular isomerism, of the design, synthesis, and properties of coordination polymers.
Abstract: Coordination polymers have been emerging as a topical research field in crystal engineering, solid-state chemistry, and materials science. Considering the wide occurrence of structural and compositional diversity during self-assembly and crystallization, supramolecular isomerism represents an indication of composition control and structure prediction. Actually, supramolecular isomerism is not just an obstacle or challenge, but also a good opportunity for developing novel materials and a better understanding of self-assembly and crystal growth. This critical review provides an overview of the developing knowledge, in the context of supramolecular isomerism, of the design, synthesis, and properties of coordination polymers (97 references).

541 citations

Journal ArticleDOI
TL;DR: An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed and several limitations do exist in terms of selectivity, limits of detection, dynamic ranges, applicability to specific problems, and reversibility.
Abstract: An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed. Notwithstanding the tremendous work performed so far,...

533 citations

Journal ArticleDOI
TL;DR: In this article, the coordination chemistry of thiosemicarbazones and all the metals for which complexes are reported are discussed with respect to their bonding and structures, variable bonding properties, metallation, metal-metal interactions, role of solvents/other factors in stabilization of sulfur-bridging in coinage metals, and the nature of substituents at azomethine carbon.

526 citations