Synthesis of undoped and manganese-doped HgTe nanoparticles using [Hg (TeCH<SUB>2</SUB>CH<SUB>2</SUB>NMe<SUB>2</SUB>)<SUB>2</SUB>] as a single source precursor

The Reaction of [HgCl<SUB>2</SUB>(tmeda)] with NaTeCH<SUB>2</SUB>CH<SUB>2</SUB>NMe<SUB>2</SUB> gave a mercury tellurolate, [Hg(TeCH<SUB>2</SUB>CH<SUB>2</SUB>.NMe<SUB>2</SUB>)<SUB>2</SUB>] (1) as a yellow crystalline solid, which was characterized by elemental analysis, UV-vis, mass and NMR (<SUP>1</SUP>H, <SUP>13</SUP>C, <SUP>125</SUP>Te, <SUP>199</SUP>Hg) spectroscopy. Thermolysis of 1 in hexadecylamine (HDA) at 90 °C in the absence and presence of Mn(OAc)<SUB>2</SUB>.4H<SUB>2</SUB>O gave undoped and Mn-doped HgTe nanoparticles which were characterized by XRD, EDAX, TEM, EPR and magnetic measurements. These particles could be synthesized with mean particle size of 6-7 nm (from TEM). Manganese substitution at Hg site in HgTe lead to a linear decrease in lattice parameter with increasing concentration of Mn. Magnetization measurements showed ferromagnetic ordering at room temperature with very small coercive field (H<SUB>c</SUB>, 50 Oe) for Hg<SUB>0.973</SUB>Mn<SUB>0.027</SUB> Te sample. This sample also exhibited distinct ferromagnetic resonance (FMR) in the EPR spectrum

Transition-metal saccharide chemistry: synthesis and characterization of D-glucose, D-fructose, D-galactose, D-xylose, D-ribose, and maltose complexes of Co(II)

Monosaccharide (D-Glc, D-Fru, D-Gal, d-Xyl, and D-Rib) and disaccharide (Mal) complexes of Co(II) were synthesised from nonaqueous solutions using [NEt4]2[CoCl2Br2] or CoCl2 · 6H2O and isolated in the solid state. The purified complexes were characterized by diffuse reflectance, aqueous solution absorbance, CD, FTIR, magnetic susceptibility, EPR, and cyclic voltammetric studies. The complexes synthesised from [NEt4]2[CoCl2Br2] were found to be primarily dinuclear, whereas those synthesised from CoCl2 · 6H2O were found to be di- or tetra-nuclear. The hydrolytic stability of the complexes followed a trend: d-Rib &gt; Mal &gt; d-Glc &gt; d-Xyl &gt; d-Fru » d-Gal

Differences in nuclearity, molecular shapes and coordination modes of azide in the complexes of Cd (II) and Hg (II) with a “Metalloligand” [CuL] (H₂L = N,N′-Bis(salicylidene)-1,3-propanediamine): characterization in solid and in solutions and theoretical calculations

Two new heterometallic copper (II)–mercury (II) complexes [(CuL)Hg(N3)2]n (1) and [(CuL)2Hg(N3)2] (2) and one copper (II)–cadmium (II) complex [(CuL)2Cd(N3)2] (3) have been synthesized using “metalloligand” [CuL] (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) and structurally characterized. Complex 1 is a one-dimensional (1D) helical coordination polymer constructed by the joining of the dinuclear [(CuL)Hg(N3)2] units through a single &#956;-l,l azido bridge. In the dinuclear unit the Hg (II) is bonded with two phenoxido oxygen atoms of “metalloligand” [CuL] and two nitrogen atoms of azido ligands. Complex 2 is a linear trinuclear entity, in which two terminal “metalloligands” [CuL] are coordinated to central Hg (II) through double phenoxido bridges. The azido ligands link the central mercury atom with the terminal copper atoms via &#956;-l,3 bridges. In contrast, the trinuclear complex 3 is bent. Here, in addition to two double phenoxido bridges, central Cd (II) is bonded to two mutually cis nitrogen atoms of two terminal azido ligands. The variation in the coordination modes of the azido ligand seems to be responsible for the different molecular shapes of 2 and 3. Interestingly, bond distances between the Hg atoms and the central nitrogen atom of the azido ligands are 2.790(4) and 2.816(5) &#197; in 1 and 2.823(4) &#197; in 2. These bond distances are significantly less than the sum of van der Waals radii of mercury (2.04 &#197;) and nitrogen (1.55 &#197;) and considerably longer than the sum of their covalent radii (2.03 &#197;). However the distances are similar to reported Hg–N bond distances of some Hg (II) complexes. Therefore, we have performed a theoretical density functional theory study to know whether there is any interaction between the central nitrogen atom of the azido ligand and the mercury atoms. We have used the Bader’s “atoms-in-molecules”, energetic and orbital analyses to conclude that such interaction does not exist. The probable reason for different molecular shapes observed in trinuclear complexes of 2 and 3 also has been studied and explained by theoretical calculations and using the CSD. Electronic spectra, EPR spectra and ESI mass spectra show that all three complexes lose their solid state identity in solution

Unprecedented structural variations in trinuclear mixed valence Co(II/III) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

Three new mixed valence trinuclear Co(II/III) compounds cis-[Co₃L₂(MeOH)₂(N₃)₂(&#956;_1,1-N₃)₂] (1), trans-[ Co₃L₂(H₂O) ₂(N₃) ₂(&#956;_1,1-N₃) ₂]•(H₂O) ₂ (2) and [Co₃L^R₂(N₃)₃(&#956;_1,3-N₃)] (3) have been synthesized by reacting a di-Schiff base ligand (H₂L) or its reduced form [H₂L^R] (where H₂L = N,N′-bis(salicylidene)-1,3-propanediamine and H₂L^R = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine) with cobalt perchlorate hexahydrate and sodium azide. All three products have been characterized by IR, UV-vis and EPR spectroscopies, ESI-MS, elemental, powder and single crystal X-ray diffraction analyses. Complex 1 is an angular trinuclear species in which two terminal octahedral Co(III)N₂O₄ centers coordinate to the central octahedral cobalt(II) ion through &#956;₂-phenoxido oxygen and &#956;_1,1-azido nitrogen atoms along with two mutually cis-oxygen atoms of methanol molecules. On the other hand, in linear trinuclear complex 2, in addition to the &#956;₂-phenoxido and &#956;_1,1-azido bridges with terminal octahedral Co(III) centres, the central Co(II) is bonded with two mutually trans-oxygen atoms of water molecules. Thus the cis–trans configuration of the central Co(II) is solvent dependent. In complex 3, the two terminal octahedral Co(III)N₂O₄ centers coordinate to the central penta-coordinated Co(II) ion through double phenoxido bridges along with the nitrogen atom of a terminal azido ligand. In addition, the two terminal Co(III) are connected through a &#956;_1,3-azido bridge that participates in pnicogen bonding interactions (intermolecular N–N interaction) as an acceptor. Both the cis and trans isomeric forms of 1 and 2 have been optimized using Density Functional Theory (DFT) calculations and it is found that the cis configuration is energetically more favorable than the trans one. However, the trans configuration of 2 is stabilized by the hydrogen bonding network involving a water dimer. The pnicogen bonding interactions have been demonstrated using MEP surfaces and CSD search which support the counter intuitive electron acceptor ability of the &#956;_1,3-azido ligand. Complexes 1–3 exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone. Kinetic data analyses of this oxidation reaction in acetonitrile reveal that the catecholase-like activity follows the order: 1 (k_cat = 142 h⁻¹) &#62; 3 (k_cat = 99 h⁻¹) &#62; 2 (k_cat = 85 h⁻¹). Mechanistic investigations of the catalytic behaviors by X-band EPR spectroscopy and estimation of hydrogen peroxide formation indicate that the oxidation reaction proceeds through the reduction of Co(III) to Co(II)

Interaction of metal ions with D-glucobenzothiazoline: isolation and characterization of the resultant products

Six different metal-ion complexes of D-glucobenzothiazoline were synthesized and characterized by analytical and spectral techniques. Formation of different types of species (ML and ML2) were observed with Cu2+, Ag+, Cd2+, Hg2+, and Zn2+ ions. Existence of an anomeric mixture in the case of the Cu2+ complex is identified from the EPR spectra, and the results were further supported by the simulated spectra. The structures were proposed based on different studies.© Elsevie

Differences in Nuclearity, Molecular Shapes, and Coordination Modes of Azide in the Complexes of Cd(II) and Hg(II) with a 'Metalloligand' [CuL] (H2L = N,N'-Bis(salicylidene)-1,3-propanediamine): Characterization in Solid and in Solutions, and Theoretical Calculations

[eng] Two new heterometallic copper(II)−mercury(II) complexes [(CuL)Hg(N3)2]n (1) and [(CuL)2Hg(N3)2] (2) and one copper(II)−cadmium- (II) complex [(CuL)2Cd(N3)2] (3) have been synthesized using "metalloligand" [CuL] (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) and structurally characterized. Complex 1 is a one-dimensional (1D) helical coordination polymer constructed by the joining of the dinuclear [(CuL)Hg(N3)2] units through a single μ‑l,l azido bridge. In the dinuclear unit the Hg(II) is bonded with two phenoxido oxygen atoms of "metalloligand" [CuL] and two nitrogen atoms of azido ligands. Complex 2 is a linear trinuclear entity, in which two terminal "metalloligands" [CuL] are coordinated to central Hg(II) through double phenoxido bridges. The azido ligands link the central mercury atom with the terminal copper atoms via μ‑l,3 bridges. In contrast, the trinuclear complex 3 is bent. Here, in addition to two double phenoxido bridges, central Cd(II) is bonded to two mutually cis nitrogen atoms of two terminal azido ligands. The variation in the coordination modes of the azido ligand seems to be responsible for the different molecular shapes of 2 and 3. Interestingly, bond distances between the Hg atoms and the central nitrogen atom of the azido ligands are 2.790(4) and 2.816(5) Å in 1 and 2.823(4) Å in 2. These bond distances are significantly less than the sum of van der Waals radii of mercury (2.04 Å) and nitrogen (1.55 Å) and considerably longer than the sum of their covalent radii (2.03 Å). However the distances are similar to reported Hg−N bond distances of some Hg(II) complexes. Therefore, we have performed a theoretical density functional theory study to know whether there is any interaction between the central nitrogen atom of the azido ligand and the mercury atoms. We have used the Bader's "atoms-in-molecules", energetic and orbital analyses to conclude that such interaction does not exist. The probable reason for different molecular shapes observed in trinuclear complexes of 2 and 3 also has been studied and explained by theoretical calculations and using the CSD. Electronic spectra, EPR spectra and ESI mass spectra show that all three complexes lose their solid state identity in solution

Differences in Nuclearity, Molecular Shapes, and Coordination Modes of Azide in the Complexes of Cd(II) and Hg(II) with a “Metalloligand” [CuL] (H₂L = <i>N</i>,<i>N</i>′‑Bis(salicylidene)-1,3-propanediamine): Characterization in Solid and in Solutions, and Theoretical Calculations

Two new heterometallic copper­(II)–mercury­(II) complexes [(CuL)­Hg­(N₃)₂]_<i>n</i> (<b>1</b>) and [(CuL)₂Hg­(N₃)₂] (<b>2</b>) and one copper­(II)–cadmium­(II) complex [(CuL)₂Cd­(N₃)₂] (<b>3</b>) have been synthesized using “metalloligand” [CuL] (where H₂L = <i>N</i>,<i>N</i>′-bis­(salicylidene)-1,3-propanediamine) and structurally characterized. Complex <b>1</b> is a one-dimensional (1D) helical coordination polymer constructed by the joining of the dinuclear [(CuL)­Hg­(N₃)₂] units through a single μ_‑l,l azido bridge. In the dinuclear unit the Hg­(II) is bonded with two phenoxido oxygen atoms of “metalloligand” [CuL] and two nitrogen atoms of azido ligands. Complex <b>2</b> is a linear trinuclear entity, in which two terminal “metalloligands” [CuL] are coordinated to central Hg­(II) through double phenoxido bridges. The azido ligands link the central mercury atom with the terminal copper atoms <i>via</i> μ_‑l,3 bridges. In contrast, the trinuclear complex <b>3</b> is bent. Here, in addition to two double phenoxido bridges, central Cd­(II) is bonded to two mutually <i>cis</i> nitrogen atoms of two terminal azido ligands. The variation in the coordination modes of the azido ligand seems to be responsible for the different molecular shapes of <b>2</b> and <b>3</b>. Interestingly, bond distances between the Hg atoms and the central nitrogen atom of the azido ligands are 2.790(4) and 2.816(5) Å in <b>1</b> and 2.823(4) Å in <b>2</b>. These bond distances are significantly less than the sum of van der Waals radii of mercury (2.04 Å) and nitrogen (1.55 Å) and considerably longer than the sum of their covalent radii (2.03 Å). However the distances are similar to reported Hg–N bond distances of some Hg­(II) complexes. Therefore, we have performed a theoretical density functional theory study to know whether there is any interaction between the central nitrogen atom of the azido ligand and the mercury atoms. We have used the Bader’s “atoms-in-molecules”, energetic and orbital analyses to conclude that such interaction does not exist. The probable reason for different molecular shapes observed in trinuclear complexes of <b>2</b> and <b>3</b> also has been studied and explained by theoretical calculations and using the CSD. Electronic spectra, EPR spectra and ESI mass spectra show that all three complexes lose their solid state identity in solution

Differences in Nuclearity, Molecular Shapes, and Coordination Modes of Azide in the Complexes of Cd(II) and Hg(II) with a “Metalloligand” [CuL] (H₂L = <i>N</i>,<i>N</i>′‑Bis(salicylidene)-1,3-propanediamine): Characterization in Solid and in Solutions, and Theoretical Calculations

Two new heterometallic copper­(II)–mercury­(II) complexes [(CuL)­Hg­(N₃)₂]_<i>n</i> (<b>1</b>) and [(CuL)₂Hg­(N₃)₂] (<b>2</b>) and one copper­(II)–cadmium­(II) complex [(CuL)₂Cd­(N₃)₂] (<b>3</b>) have been synthesized using “metalloligand” [CuL] (where H₂L = <i>N</i>,<i>N</i>′-bis­(salicylidene)-1,3-propanediamine) and structurally characterized. Complex <b>1</b> is a one-dimensional (1D) helical coordination polymer constructed by the joining of the dinuclear [(CuL)­Hg­(N₃)₂] units through a single μ_‑l,l azido bridge. In the dinuclear unit the Hg­(II) is bonded with two phenoxido oxygen atoms of “metalloligand” [CuL] and two nitrogen atoms of azido ligands. Complex <b>2</b> is a linear trinuclear entity, in which two terminal “metalloligands” [CuL] are coordinated to central Hg­(II) through double phenoxido bridges. The azido ligands link the central mercury atom with the terminal copper atoms <i>via</i> μ_‑l,3 bridges. In contrast, the trinuclear complex <b>3</b> is bent. Here, in addition to two double phenoxido bridges, central Cd­(II) is bonded to two mutually <i>cis</i> nitrogen atoms of two terminal azido ligands. The variation in the coordination modes of the azido ligand seems to be responsible for the different molecular shapes of <b>2</b> and <b>3</b>. Interestingly, bond distances between the Hg atoms and the central nitrogen atom of the azido ligands are 2.790(4) and 2.816(5) Å in <b>1</b> and 2.823(4) Å in <b>2</b>. These bond distances are significantly less than the sum of van der Waals radii of mercury (2.04 Å) and nitrogen (1.55 Å) and considerably longer than the sum of their covalent radii (2.03 Å). However the distances are similar to reported Hg–N bond distances of some Hg­(II) complexes. Therefore, we have performed a theoretical density functional theory study to know whether there is any interaction between the central nitrogen atom of the azido ligand and the mercury atoms. We have used the Bader’s “atoms-in-molecules”, energetic and orbital analyses to conclude that such interaction does not exist. The probable reason for different molecular shapes observed in trinuclear complexes of <b>2</b> and <b>3</b> also has been studied and explained by theoretical calculations and using the CSD. Electronic spectra, EPR spectra and ESI mass spectra show that all three complexes lose their solid state identity in solution

Probing the local structure and phase transitions of Bi<SUB>4</SUB>V<SUB>2</SUB>O<SUB>11</SUB>-based fast ionic conductors by combined Raman and XRD studies

In this article, we report the structural phase transitions in Bi<SUB>4</SUB>V<SUB>2</SUB>O<SUB>11</SUB> as observed from temperature-dependent Raman scattering and X-ray diffraction measurements. Four different types of highly disordered coordination polyhedra around the vanadium atoms with large dispersion of V–O bond lengths are observed in Bi<SUB>4</SUB>V<SUB>2</SUB>O<SUB>11</SUB> at ambient temperature. The observed V–O bond lengths could be grouped into two categories, viz. shorter &#60;1.7 Å and longer >1.7 Å. The Raman modes of Bi<SUB>4</SUB>V<SUB>2</SUB>O<SUB>11</SUB> could be assigned to vibration of these bonds and V–O–V linkages. We could correlate the difference in degree of anharmonicity of the phonon modes with temperature to differences in V–O bond strength. The local structure of vanadium–oxygen network in Bi<SUB>4</SUB>V<SUB>1.8</SUB>Cu<SUB>0.2</SUB>O<SUB>10.7</SUB> was also obtained by similar studies. The effect of highly disordered anion sublattice in the doped compound is reflected in the broadening of the Raman modes