Shyamapada Shit

2,2′-Bipyridyl-acetylphenolato mixed ligand copper(II) complexes: syntheses, characterizations and catalytic activity in styrene epoxidation

Two copper(II) complexes, [Cu(bipy)(5-Br-2-hap)(ClO4)]2 (1) and [Cu(bipy)(2-hap)(ClO4)] (2) (where bipy = 2,2′-bipyridine, 5-Br-2-hap = 5-bromo-2-hydroxyacetophenone, 2-hap = 2-hydroxyacetophenone), were synthesized and characterized. The crystal structure of 1 was determined by single crystal X-ray diffraction while 2 was reported earlier. Structural characterization reveals that the presence of bromine in 5-Br-2-hap plays a structure-determining role in dimeric 1 in comparison with the mononuclear 2 where 2-hap was used. Studies of the catalytic potential toward styrene epoxidation in homogeneous system using H2O2 as oxidant reveal that 1 is more efficient than 2 with respect to epoxide selectivity.

Sodium-mediated self-assembly of two nickel(II) Schiff base complexes: crystal structure and characterizations

Sodium-assisted self-assembly of two nickel(II) Schiff base complexes under similar reaction conditions yield hetero-metallic compounds [{Ni(salpn)}2Na(ClO4)] (1) and [{Ni(salpr)}3Na][Ni(salpr)]2ClO4·2H2O (2) (where salpn = N,N′-bis-(salicylidene)-1,3-diaminopropane and salpr = N,N′-bis-(salicylidene)-1,2-diaminopropane). Both have been characterized by physico-chemical techniques and single-crystal X-ray diffraction. Crystal structure reveals that in the tri-metallic system of 1 sodium is sandwiched between two [Ni(salpn)] units while the hexametallic system of 2 consists of tetrametallic cluster ion [{Ni(salpr)}3Na]+ with encapsulated sodium by three [Ni(salpr)] units. In both complexes, sodium adopts distorted trigonal prismatic geometry leaving nickel(II) in a distorted square-planar environment. Structural characterization also reveals that 2 : 1 (for 1) and 3 : 1 (for 2) self-assemblies of metallo-ligand and sodium were achieved with slight variation in ligand backbone.

Synthesis, Structure and Fluorescence Properties of a Trinuclear Zn(II) Complex with N,N,O-donor Schiff Base Ligands and Bridging Acetates

A new centrosymmetric trinuclear Zn(II) complex [Zn3L2(CH3COO)4] (1) has been synthesized by the reaction of Zn(CH3COO)2 · 2H2O with a tridentate N,N,O-donor Schiff base ligand HL [C5H4NC(CH3)=NC6H4(OH)] and systematically characterized by elemental analysis, FT-IR, UV/Vis and thermal methods. Single crystal X-ray structure analysis reveals that three Zn(II) centers are in two different coordination environments. Two terminal Zn(II) centers adopt a distorted squarepyramidal geometry leaving the central Zn(II) in a distorted octahedral environment. Two adjacent metal centers are connected through single μ2-phenolato as well as double μ-acetato-O,O´ syn-syn bridges. Fluorescence properties of the complex as compared to the ligand indicate that the former can serve as a potential photoactive material. Graphical Abstract Synthesis, Structure and Fluorescence Properties of a Trinuclear Zn(II) Complex with N,N,O-donor Schiff Base Ligands and Bridging Acetates

Ferromagnetic copper(II)–copper(II) interaction in a single chlorido and dicyanamido bridged mixed–valence copper(I/II) 2-D polymer generated by in situ partial reduction of copper(II)

A mixed-valence 2-D Cu(I/II) complex, [{Cu(II)(dmen)(μ-Cl)(μ1,5-dca)}{Cu(I)(μ1,5-dca)}]n (1) (dmen = N,N-dimethylethylenediamine, dca = dicyanamide = [N(CN)2]−), has been synthesized by in situ partial reduction of Cu(II) to Cu(I) using benzoin (2-hydroxy-1,2-di(phenyl)ethanone) as reductant. Complex 1 was characterized by spectroscopic techniques, single crystal X-ray diffraction, and low temperature magnetic measurements. Structural investigation reveals that 1 represents a mixed-valence 2-D coordination polymer formed by parallel 1-D [Cu(II)(dmen)(Cl)Cu(I)(μ1,5-dca)2]n chains running along the b axis, where chloride bridges Cu(II) ions of adjacent polymers through long connections (2.8401(1) Å) to form a 2-D network. The metal centers have two different geometrical environments (distorted square pyramidal and distorted trigonal planar geometries for Cu(II) and Cu(I), respectively). The Cu(II) ions in [Cu(II)(dmen)(μ-Cl)(dca)]n are interconnected through single chloride bridges while within the [Cu(I)(μ1,5-dca)]n units, the dca connects adjacent Cu(I) ions through μ1,5-dca bridges. Magnetic susceptibility measurements reveal weak ferromagnetic interactions (J = +0.3 cm−1) within the chlorido-bridged Cu(II) regular chain present in 1. Simultaneous presence of μ1,5-dca and single chlorido bridges with ferromagnetic coupling is believed to be unique in mixed-valence Cu(I)/Cu(II) complexes.

Synthesis, crystal structure and fluorescence properties of two dinuclear zinc(II) complexes incorporating tridentate (NNO) Schiff bases

Abstract Reactions of hydrated zinc(II) trifluoroacetate and sodium azide with two tridentate Schiff bases HL1 (2-((E)-(2-(dimethylamino)ethylimino)methyl)-4-chlorophenol) and HL2 (2-((E)-(2-(dimethylamino)ethylimino)methyl)-4-bromophenol) under the same reaction conditions yielded two dinuclear isostructural zinc(II) complexes, [Zn(L1)(N3)]2 (1) and [Zn(L2)(N3)]2 (2), respectively. The complexes were characterized systematically by elemental analysis, UV–Vis, FT-IR, and 1H NMR spectroscopic methods. Single-crystal X-ray diffraction studies reveal that each of the dinuclear complexes consists of two crystallographically independent zinc(II) ions connected by double bridging phenoxides. All zinc(II) ions in 1 and 2 are surrounded by similar donor sets and display distorted square–pyramidal coordination geometries. The ligands and complexes reveal intraligand 1(π → π*) flourescence. The enhancement of the fluorescence intensities for the complexes compared to the ligands indicates their potential to serve as photoactive materials.

Trigonal dodecahedral sodium coordination in a trinuclear copper(II)-sodium complex incorporating a salen-type compartmental Schiff base

Abstract A new trinuclear heterometallic complex, [(CuL)Na(CuL)]·ClO4 (1), has been prepared using a Schiff base, H2L (where H2L=N,N′-(1,2-phenylene)-bis(3-methoxysalicylideneimine) and characterized by elemental analysis, Fourier transform infra-red (FT-IR) spectroscopy, UV/Vis, magnetic, electrochemical, and single crystal X-ray diffraction methods. The structure analysis reveals that two metallo-ligand [(CuL)] units are connected to each other by a sodium ion resulting in the cationic unit [(CuL)Na(CuL)]+. Both the copper(II) ions display an almost square planar geometry while the sodium ion adopts a trigonal-dodecahedral coordination geometry. The spectroscopic and other physicochemical studies are in good agreement with the crystal structure of the complex.

Temperature dependent growth of cadmium(II) oxide nanocrystals: studies on morphology based optical, electrical and dielectric properties

Nanocrystalline cadmium(II) oxide were obtained by calcining a hydrated cadmium-organic hybrid precursor, (C10H2O8)Cd2·xH2O, obtained by a chemical reduction method using cadmium acetate dihydrate, 1,2,4,5-benzenetetracarboxylic acid, and triethylamine. Calcined CdO at different temperature possess different morphology, revealed by field emission scanning electron microscope analysis. In this article, the photosensitivity, dielectric behavior, frequency dependant loss-tangent and complex impedance spectra of the morphology driven CdO nanoparticles were studied aptly.

Crystal structure, characterization and magnetic properties of a 1D copper(II) polymer incorporating a Schiff base with carboxylate side arm

AbstractA new 1D polymeric copper(II) complex [{Cu(L)(CF3COO)}2]n has been synthesized using a potentially tetradentate Schiff base ligand, HL, ((E)-2-((pyridin-2-yl)methyleneamino)-5-chlorobenzoic acid) and characterized by different spectroscopic methods. Single crystal X-ray structural characterization reveals that the side arm carboxylate group of the coordinated Schiff base exhibits a μ1,3-bridging mode and connects the neighbouring copper(II) ions leading to a zigzag 1D chain structure where the copper(II) ions display distorted square pyramidal geometries. Variable temperature magnetic susceptibility measurement reveals a weak antiferromagnetic exchange (J = −0.47 ± 0.01 cm−1) prevails between copper(II) ions in the chain mediated by the bridging carboxylate group, is also supported by the room temperature EPR spectral study. Electrochemical property of the complex is also reported. Graphical AbstractSyn-anti μ1,3- bridging mode of the side arm carboxylato oxygen atoms of the coordinated Schiff base result in a zigzag 1D copper(II) chain complex, [{Cu(L)(CF3COO)}2]n, which shows antiferromagnetic interaction (J = ‒0.47 ± 0.01 cm‒1).

Synthesis of 1,1′-(2,6-dihydroxy-2,6-dimethyl-3,7-dioxabicyclo [3.3.1]nonane-1,5-diyl)diethanone dihydrate: crystal structure and quantitative analysis of molecular interaction via molecular electrostatic potential and Hirshfeld surface analysis

ABSTRACT A new bicyclononane derivative, 1,1′-(2,6-dihydroxy-2,6-dimethyl-3,7-dioxa-bicyclo[3.3.1]nonane-1,5-diyl) diethanone dihydrate (1), has been synthesized and structurally characterized by the single-crystal X-ray diffraction technique. In the solid-state structure of the compound, molecular units are interlinked via strong hydrogen bonds as well as non-classical weak hydrogen bonds leading to a three-dimensional supramolecular architecture. Solid-state DFT optimized geometry in (1) agrees closely with that obtained from the crystallographic analysis. The C(dioxa-bicyclononane)–H … O(hydroxy) hydrogen bond generates cyclic (10) ring in (1) which are further connected through C–H … O and O–H … O hydrogen bonds into a three-dimensional framework in the title compound. Hirshfeld surface analysis of the title compound along with some related nonane derivatives retrieved from the Cambridge Structural Database shows that the most of the Hirshfeld surface area in this class of compounds is due to H … H and O … H interactions.

Synthesis, characterization, and crystal structure of a four-coordinate cobalt(II) compound incorporating bis(3,5-dimethylpyrazol-1-yl)methane and cyanate

ABSTRACT A new mononuclear cobalt(II) compound [Co(dmpzm)(NCO)2] (1) (where dmpzm = bis(3,5-dimethylpyrazol-1-yl)methane and NCO− = cyanate) has been synthesized and characterized by different physicochemical methods. Crystal structure of the compound is established by single-crystal X-ray diffraction analysis, which reveals that central cobalt(II) adopts distorted tetrahedral geometry and is coordinated by two nitrogen atoms of a bis-chelating dmpzm ligand and nitrogen atoms of two monodentate cyanate ions. Crystal structure is further stabilized by intermolecular C–H···O interactions, generating one-dimensional chain structure. The electrochemical properties of the compound were studied by cyclic voltammetric method. Room temperature magnetic susceptibility measurements reveal the presence of high-spin cobalt(II) ion in 1.