Synthesis and crystal structure characterization of iron(II), cobalt(II) and nickel(II) complexes with 1,3-bis(2-pyridylmethylthio)propane

Three new mononuclear complexes of nitrogen-sulfur donor sets, formulated as (Fe-II(L)Cl-2] (1), [Co-II(L)Cl-2] (2) and [Ni-II(L)Cl-2] (3) where L = 1,3-bis(2-pyridylmethylthio)propane, were synthesized and isolated in their pure form. All the complexes were characterized by physicochemical and spectroscopic methods. The solid state structures of complexes I and 3 have been established by single crystal X-ray crystallography. The structural analysis evidences isomorphous crystals with the metal ion in a distorted octahedral geometry that comprises NSSN ligand donors with trans located pyridine rings and chlorides in cis positions. In dimethylformamide solution, the complexes were found to exhibit Fe-II/Fe-III, co(II)/co(III) and Ni-II/Ni-III quasi-reversible redox couples in cyclic voltammograms with E-1/2 values (versus Ag/AgCl at 298 K) of +0.295, +0.795 and +0.745 V for 1, 2 and 3, respectively. (C) 2009 Elsevier Ltd. All rights reserved.

Copper(II) complexes of tetradentate N2S2 donor sets: synthesis, crystal structure characterization and reactivity

Two mononuclear and one dinuclear copper(II) complexes, containing neutral tetradentate NSSN type ligands, of formulation [Cu-II(L-1)Cl]ClO4 (1), [Cu-II(L-2)Cl]ClO4 (2) and [Cu-2(II)(L-3)(2)Cl-2](ClO4)(2) (3) were synthesized and isolated in pure form [where L-1 = 1,2-bis(2-pyridylmethylthio)ethane, L-2 = 1,3-bis(2-pyridylmethylthio)propane and L-3 = 1,4-bis(2-pyridylmethylthio)butane]. All these green colored copper(II) complexes were characterized by physicochemical and spectroscopic methods. The dinuclear copper(II) complex 3 changed to a colorless dinuclear copper(I) species of formula [Cu-2(1)(L-3)(2)](ClO4)(2),0.5H(2)O (4) in dimethylformamide even in the presence of air at ambient temperature, while complexes I and 2 showed no change under similar conditions. The solid-state structures of complexes 1, 2 and 4 were established by X-ray crystallography. The geometry about the copper in complexes 1 and 2 is trigonal bipyramidal whereas the coordination environment about the copper(I) in dinuclear complex 4 is distorted tetrahedral. (C) 2008 Elsevier Ltd. All rights reserved.

Interferometric technique for measuring terahertz antenna phase patterns

A quasi-optical interferometric technique capable of measuring antenna phase patterns without the need for a heterodyne receiver is presented. It is particularly suited to the characterization of terahertz antennas feeding power detectors or mixers employing quasi-optical local oscillator injection. Examples of recorded antenna phase patterns at frequencies of 1.4 and 2.5 THz using homodyne detectors are presented. To our knowledge, these are the highest frequency antenna phase patterns ever recovered. Knowledge of both the amplitude and phase patterns in the far field enable a Gauss-Hermite or Gauss-Laguerre beam-mode analysis to be carried out for the antenna, of importance in performance optimization calculations, such as antenna gain and beam efficiency parameters at the design and prototype stage of antenna development. A full description of the beam would also be required if the antenna is to be used to feed a quasi-optical system in the near-field to far-field transition region. This situation could often arise when the device is fitted directly at the back of telescopes in flying observatories. A further benefit of the proposed technique is simplicity for characterizing systems in situ, an advantage of considerable importance as in many situations, the components may not be removable for further characterization once assembled. The proposed methodology is generic and should be useful across the wider sensing community, e.g., in single detector acoustic imaging or in adaptive imaging array applications. Furthermore, it is applicable across other frequencies of the EM spectrum, provided adequate spatial and temporal phase stability of the source can be maintained throughout the measurement process. Phase information retrieval is also of importance to emergent research areas, such as band-gap structure characterization, meta-materials research, electromagnetic cloaking, slow light, super-lens design as well as near-field and virtual imaging applications.

Trichloro-mono-beta-diketonato oxorhenium(V) complexes: synthesis, characterization and crystal structure

Oxorhenium(V) complexes of beta-diketonate systems have been synthesized and isolated in pure form. The red complexes n-Bu4N[ReO(R1COCHCOR2)Cl-3] (acac, R-1=R-2=CH3; bzac, R-1=CH3 and R-2=C6H5; bzbz, R-1=R-2=C6H5) have been characterized by elemental analyses, spectroscopic and other physico-chemical tools. One complex, n-Bu4N[ReO(bzbz)Cl-3] (1c) has been subjected to single-crystal X-ray analysis. In the structure of the anion, the metal has a six-coordinate octahedral environment in which the bidentate -diketone ligand is cis and trans to the terminal oxygen.

Zinc(II)-pyridylthioazophenol system: synthesis, characterization and crystal structure

Reactivities of pyridylthioazophenols (1) with zinc(II) salts have been studied and the complexes isolated in pure form and characterized. Pyridylthioazophenols react with zinc( II)acetate in MeOH/EtOH at room temperature to give a series of pyridylsulfinylazophenols (2)but no zinc( II) complex. The sulfoxides (2) have been characterized by IR and NMR. One of the pyridylsulfinylazophenols (2a) has been subjected to single-crystal X-ray analysis in order to confirm details of its structure. A series of dimeric zinc( II) complexes of tetradentate NSNO pyridylthioazophenolates has been isolated through reaction of zinc nitrate in MeOH followed by in situ reaction with azide ion, which acts as a mu-(1,1) bridge. All complexes have been characterized spectroscopically. The detailed structure of one of the dinuclear zinc( II) complexes has been established by a single-crystal X-ray structure determination. In complex 3a two octahedrally coordinated zinc( II) ions are bridged by two end-on azide ions. No reactions of pyridylthioazophenols with zinc chloride in refluxing EtOH have been observed.

Nickel(II) complexes of tetradentate NSNO pyridylthioazophenol ligands: synthesis, characterization and crystal structure

Two sets of nickel(11) complexes of a series of tetradentate NSNO ligands were synthesized and isolated in their pure form. All these complexes, formulated as [Ni(L)Cl](2) and [Ni(L)(N-3)](2) [HL = pyridylthioazophenols], were characterized using physicochemical and spectroscopic tools. The solid-state structures of two complexes (1a and 2a) were established by X-ray crystallography. The geometry about the nickel ion of the complexes is octahedral and the complexes are dimeric in nature. In 1, two Ni(II) ions are bridged by two Cl- anions while in 2 they are bridged by two azide ions in a mu-1,1-bridging fashion. (C) 2008 Elsevier Ltd. All rights reserved.

A novel cation induced polymeric chain in Na-8[{Cu(gly)(2)}(2)]{H-2(H2W12O42)}] center dot 24H(2)O: hydrothermal synthesis, spectroscopic characterization and X-ray structure analysis

A novel bis(glycinato) copper(II) paradodecatungstate Na-8[{Cu(gly)(2)}(2)]-{H-2(H2W12O42)}] center dot 24H(2)O (1) has been synthesized under hydrothermal conditions. The crystal structure of 1 reveals an infinite one-dimensional chain along the [100] direction and is built from paradodecatungstate (H2W12O42)(10-) clusters joined through [Cu(gly)(2)] moieties. Parallel chains are interlinked by NaO6 octahedra to generate a two-dimensional network.

Synthesis and characterization of carbamoyl methyl pyrazole(CMPz) compounds of palladium(II) chloride: the crystal and molecular structure of [PdCl2{(C3H3N2CH2CONBu2)-Bu-i}(2)]

Carbamoyl methyl pyrazole compound of palladium(II) chloride of the type [PdCl2L2] (where L = C5H7N2CH2CON(C4H9)(2), C5H7N2CH2CON((C4H9)-C-i)(2), C3H3N2CH2CON(C4H9)(2), or C3H3N2CH2CON((C4H9)-C-i)(2)) has been synthesized and characterized by IR and H-1 NMR spectroscopy. The structure of the compound [PdCl2{(C3H3N2CH2CONBu2}2)-Bu-i] has been determined by single crystal X-ray diffraction and shows that the ligands are bonded through the soft pyrazolyl nitrogen atom to the palladium(II) chloride in a trans disposition. (c) 2007 Elsevier B.V. All rights reserved.

Characterization of the layered structure in main chain dibenzo-18-crown-6 ether polymers by simultaneous WAXS/MAXS-SAXS/DSC measurements

The structure and thermal properties of polymers containing dibenzo-18-crown-6 ether units in the main chain linked to an aliphatic spacer of different lengths (C10-C14) is reported. X-ray diffraction patterns of all the studied samples exhibit a peak in the medium angle region, revealing the existence of a lamellar structure. Simultaneous calorimetry and small, medium (SAXS-MAXS) and wide (WAXS) X-ray measurements during cooling and subsequent heating of the samples reveal that a layer phase is formed upon cooling. In the case of the homopolymers, this phase is almost simultaneously accompanied by the appearance of some reflections in the wide angle region as an indication of lateral crystallization. However, by copolymerization, the formation of the layer phase is decoupled from lateral crystallization, being stable in a wide temperature region.

Coordination behavior of symmetrical hexadentate O2N2S2-donor Schiff bases toward zinc (II): synthesis, characterization, and crystal structure

Two series of zinc(II) complexes of two Schiff bases (H2L1 and H2L2) formulated as [Zn(HL1/HL2)]ClO4 (1a and 1b) and [Zn(L1/L2)] (2a and 2b), where H2L1 = 1,8-bis(salicylideneamino)-3,6-dithiaoctane and H2L2 = 1,9-bis(salicylideneamino)-3,7-dithianonane, have been prepared and isolated in pure form by changing the chemical environment. Elemental, spectral, and other physicochemical results characterize the complexes. A single crystal X-ray diffraction study confirms the structure of [Zn(HL1)]ClO4 (1a). In 1a, zinc(II) has a distorted octahedral environment with a ZnO2N2S2 chromophore.

Cobalt(III) complexes of some aromatic thiohydrazides – Synthesis, characterization and structure

Co(NH3)(5)Cl]Cl-2 forms neutral 1:3 complex by reaction with aromatic thiohydrazides, i.e. thiobenzhydrazide, o-hydroxythiobenzhydrazide, thiophen-2-thiohydrazide and furan-2-thiohydrazide. All these complexes are diamagnetic and have been characterized by elemental analysis and combination of spectroscopic methods. Cyclic voltammometry of the complexes shows irreversible metal centered and ligand centered electron transfer reactions. One complex, tris-o-hydroxythiobenzhydrazidocobalt(III),has been crystallized from DMSO solution to produce solvated crystals and its structure has been established by X-ray crystallography. Cobalt(III) ion is linked through three hydrazinic nitrogen and three sulfur atoms of three identical deprotonated ligand molecules in a distorted octahedral environment. Involvement of -OH group in intramolecular and intermolecular hydrogen bonding is crucial for crystal formation.

Synthesis, characterization and molecular structure of 1,1′ bis(diphenylphosphino ferrocene)dioxide complex of uranyl nitrate

A 1,1' bis(diphenylphosphino ferrocene) dioxide complex of uranyl nitrate was synthesized and characterized by IR, H-1 and P-31{H-1} NMR spectroscopic and X-ray diffraction methods. The structure of the compound shows that the uranium atom is surrounded by eight oxygen atoms in a hexagonal bi-pyramidal geometry. Two oxygen atoms from 1,1' bis(diphenylphosphino ferrocene) dioxide ligand and four oxygen atoms from the nitrate groups form a planar hexagon. The two uranyl oxygen atoms occupy the axial position. The 1,1' bis(diphenylphosphino ferrocene) dioxide ligand acts as a bidentate chelating ligand with a bite angle of 71.56(8)degrees around the uranium(VI) atom, which is much smaller in value compare to any of the previously reported values (90.1 degrees-154.0 degrees) for this ligand.

Synthesis and structure of oligomeric dimesitylgermyl-substituted carbodiimides; characterization of higher oligomers

New cyclic oligomers of dimesitylgermylene carbodiimides (Mes2GeNCN)n (n = 3 (1) and 4 (2)) were synthesized by reactions of dimesityldichlorogermane with either cyanamide in the presence of triethylamine or lithium cyanamide. The reactions always gave 1, the trimer of the hypothetical (Mes2GeN−CN), as the major compound. Higher oligomers 3 (n up to 20−30) also can be isolated, depending on the reaction conditions. In THF solution at room temperature, 2 and 3 slowly isomerize to 1, which seems to be the most stable compound. X-ray analysis of trimer 1 and tetramer 2 shows unstrained tetrahedral germanium atoms and linear diimine linkers.

Synthesis, chemical, electrochemical characterization of oxomolybdenum(V) complexes of 2-(3,5-dimethyl pyrazol-1-yl) benzothiazole ligand: crystal structure of ligand and oxomolybdenum(VI) complex and density functional theory (DFT) calculation

This work reports the ligational behavior of the neutral bidentate chelating molecule 2-(3,5-dimethyl pyrazol-1-yl) benzothiazole towards the oxomolybdenum(V) center. Both mononuclear complexes of the type (MoOX3L)-O-V and binuclear complexes of the formula (Mo2O4X2L2)-O-V (where X = Cl, Br) are isolated in the solid state. The complexes are characterized by elemental analyses, various spectroscopic techniques (UV-Vis IR), magnetic susceptibility measurement at room temperature, and cyclic voltammetry for their redox behavior at a platinum electrode in CH3CN. The mononuclear complexes (MoOX3L)-O-V are found to be paramagnetic while the binuclear complexes Mo2O4X2L2 are diamagnetic. Crystal and molecular structure of the ligand and the dioxomolybdenum complex (MoO2Br2L)-O-VI (obtained from the complex MoOBr3L during crystallization) have been solved by single crystal X-ray diffraction technique. Relevant DFT calculations of the ligand and the complex (MoO2Br2L)-O-VI are also carried out.