V. Kumar

Bio: V. Kumar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Bromide & Hydrobromic acid. The author has an hindex of 2, co-authored 5 publications receiving 12 citations.

A novel mixed valence iodide bridged Te(II)-Te(IV) complex featuring diisopropyldithiocarbamate(L) and iodide: ILTeII(I)TeIVL2I

Abstract: The title compound is a novel mixed ligand and mixed valence complex of tellurium, the crystal structure of which is reported here. The compound crystallizes in the orthorhombic space group, Pca21 with four molecules per unit cell, the dimensions of which area=15.209(1),b=20.159(2),c=12.453(1) A. The structure was solved by the heavy-atom method and refined by fullmatrix least-squares method to a finalR=0.046 andRw=0.046 for 3011 unique reflections. The structure could be considered as 1∶1 adduct of TeIVL2I2 and TeIILI (L=diisopropyldithiocarbamate). The two tellurium atoms, TeII[Te(1)] and TeIV[Te(2)] display entirely different coordinations and are bridged through iodine I(1) in a symmetrical manner. There is a short Te(1)⋯Te(2) contact distance of 3.542(1) A.

2-(2-THIOXO-1,3-THIAZOLIDIN-3-YL)-4,5-DIHYDRO-l,3-THIAZOLIUM BROMIDE. 1HNMR, MASS SPECTRAL, X-PES STUDIES AND

Abstract: The title compound is formed by the rearrangement of 2,2′-dithiobis[4,5-dihydrothiazole] with the extrusion of one sulfur in dilute hydrobromic acid medium. 1HNMR, Mass spectral, X-PES studies and crystal structure determination have been carried out. While the Mass spectrum showed the presence of three sulfurs in the molecule, the presence of four triplets in the 1HNMR spectrum ruled out the symmetrical sulfide isomer. The unit cell is monoclinic, P21/c, with a = 11.236(1), b = 10.138(1), c = 9.571(1)A, β = 111.89°(1), V = 1011.63A3, D m = 1.85 Mg/m3 D c = 1.86 Mg/m3, at 2% K for four molecules per unit cell. From 1498 unique reflections for which I > 3σ (I), R = 0.051, with anisotropic thermal parameters for all non-hydrogen atoms. Both the five membered heterocyclic rings adopt the half chair conformation. Hydrogen bonding occurs involving the dihydrothiazolyl nitrogen, the proton attached to it and the bromide.

Synthesis and structure of bisiodobis(diisopropyldithiocarbamato)tellurium(IV)

Abstract: The title mixed ligand complex was synthesized by the controlled oxidative displacement reaction of TeL 4 ″ by iodine (L″ is diisopropyldithiocarbamate ion). Its crystals are monoclinic, space group P21 withZ=2 in a unit cell of dimensionsa=8.344(4),b=14.113(8),c=10.647(5) A,β=99.884(2)°, andV=1235.15 A3, finalR=0.043 andR w =0.047 for 3553 unique reflections. The central tellurium atom shows a S4I2 six coordination with the two dithiocarbamate groups almost isobidentate, the average Te-S and the Te-I distances being 2.571(3) and 3.011(1) A, respectively. The structure is monomeric in the solid state. No intermolecular short contacts are observed.

The nature of the chemical bond in linear three-body systems: from i3- to mixed chalcogen/halogen and trichalcogen moieties.

Abstract: The 3 centre-4 electrons (3c-4e) and the donor/acceptor or charge-transfer models for the description of the chemical bond in linear three-body systems, such as I3– and related electron-rich (22 shell electrons) systems, are comparatively discussed on the grounds of structural data from a search of the Cambridge Structural Database (CSD). Both models account for a total bond order of 1 in these systems, and while the former fits better symmetric systems, the latter describes better strongly asymmetric situations. The 3c-4e MO scheme shows that any linear system formed by three aligned closed-shell species (24 shell electrons overall) has reason to exist provided that two electrons are removed from it to afford a 22 shell electrons three-body system: all combinations of three closed-shell halides and/or chalcogenides are considered here. A survey of the literature shows that most of these three-body systems exist. With some exceptions, their structural features vary continuously from the symmetric situation showing two equal bonds to very asymmetric situations in which one bond approaches to the value corresponding to a single bond and the second one to the sum of the van der Waals radii of the involved atoms. This indicates that the potential energy surface of these three-body systems is fairly flat, and that the chemical surrounding of the chalcogen/halogen atoms can play an important role in freezing different structural situations; this is well documented for the I3– anion. The existence of correlations between the two bond distances and more importantly the linearity observed for all these systems, independently on the degree of their asymmetry, support the state of hypervalency of the central atom.

The Thiocarbonyl Group

Abstract: 1 Introduction 2 Energetics and Structure of Thiocarbonyl Compounds.Their Influence on Reactivity and Physical Properties 3 Syntheses 4 Chemical Properties of Thiocarbonyl Compounds 5 Coordination Chemistry 6 Acknowledgments Keywords: thiocarbonyl group; energetics and thiocarbonyl compound structure; photoelectron spectroscopy (PES); addition reactions to alkynes and alkenes; cycloreversion reactions; reductive C,S cleavage; desulfurization reactions; coordination chemistry

Recent Developments in the Structural Chemistry of Tellurium with Sulfur and Selenium Containing Ligands

Abstract: Since the author's last surveys of this field in 1983 and 1987,1,2 there has been considerable developments in the structural chemistry of tellurium. A comprehensive review covers the field through most of 1993.3