Synthesis and crystal structure of bis{(μ-chloro)-chloro-[N-benzoyl-N′-(2-hydroxyethyl)thiourea] mercury(II)}

The complex bis{(µ-chloro)-chloro-[N-benzoyl-N′-(2-hydroxyethyl)thiourea] mercury(II)} was prepared by reaction of HgCl₂ with N-benzoyl-N′-(2-hydroxyethyl) thiourea(HL). The compound was characterized by IR and ¹H?NMR spectroscopy and its structure was determined by single crystal X-ray diffraction. The complex is binuclear with two Hg(II) ions tetrahedrally coordinated by a terminal chloride, two bridging chlorides and a HL molecule. The Hg(II) ion is coordinated with HL via S(1).     

Crystal structure of tetra(μ-acetato)-bis{[1-ethyl-3-(pyridine-2-yl)carbamide]copper}

The crystal structure of tetra(μ-acetato)-bis{[1-ethyl-3-(pyridine-2-yl)carbamide]copper} Cu₂(L)₂(CH₃COO)₄ (I), where L is 1-ethyl-3-(pyridine-2-yl)carbamide, is determined. The asymmetric unit cell of the crystal structure of I contains a copper complex with two acetate ions and a monodentate molecule of 1-ethyl-3-(pyridine-2-yl)carbamide, which is coordinated via the pyridine nitrogen atom. Due to the symmetry center, binuclear complexes form in the crystal, in which the acetate ions act as bridges between the metal atoms. In them, the coordination polyhedron of the central copper atoms represents an almost ideal tetragonal pyramid. Its base is formed from the oxygen atoms of acetate ions. In the crystal of the binuclear complex, hydrogen bonds form between the acetate ions and the L ligand along with an intramolecular hydrogen bond, which stabilize the conformation of the organic L molecule. Between the neighboring complexes in the crystal, the van der Waals interaction occurs.     

Synthesis and Structure of Bis[2,6-bis(2-pyridylamino)pyridinium] Tetrachlorocadmiumate(II)

1 INTRODUTION The d10 configuration of Cd(II) permits a wide variety of coordination numbers and geometries[1~3]. In recent years, one-, two- and three-dimensional infinite supramolecular coordination assemblies of Cd(II) have been the subject of great interest owing to their potential applications in catalysis, optical properties, clathration, etc[4~8]. In fabricating the coordination assemblies, organic ligands as well as inorganic anions have been observed to control the structural di…     

Electrochemical and spectral properties of the polymer form of Cu(II) complex with N,N′-bis(salicylidene)-1,3-propylenediamine

A conductive polymer based on the Cu(II) complex with N,N′-bis(salicylidene)-1,3-propylenediamine was obtained electrochemically. The optimal mode of the synthesis of the polymer under potentiostatic conditions was found. We determined the charge diffusion coefficient and activation barrier and elucidated the nature of the limiting step of the charge transfer in the polymer bulk in the electrolyte medium. The azomethine base, Cu(II) complex, and its polymer form in the oxidized and reduced states were characterized by X-ray photoelectron spectroscopy and electron absorption spectroscopy.     

Poly­[copper(II)-μ-pyrazine-μ3-squarato]

In the structure of the title compound, [Cu(C₄O₄)(C₄H₄N₂)]_n, each copper cation is surrounded by three squarate (3,4-di­hydroxy-3-cyclo­butene-1,2-dioate) anions and two pyrazine ligands, all of which are located in special positions. The copper cation and all atoms of the squarate anion are located on a mirror plane, whereas the pyrazine ligand is located around a mirror plane which is perpendicular to the ring plane. The cations are connected via the squarate anions and the pyrazine ligands, forming sheets parallel to (001).     

Synthesis and Crystal Structure of Bisaqua-[N,N′-bis(3,5-dichlorosalicylidene)-1,3-diaminopropano]zinc(Ⅱ)

The title mononuclear zinc(Ⅱ) complex [Zn(BCDP)(H2O)2] (BCDP = N,N′-bis(3,5-dichlorosalicylidene)-1,3-diaminopropane) was prepared and characterized by elemental analysis,IR spectra and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Pnma with a = 7.887(1), b = 23.788(2), c = 10.295(4) (A), Z= 4, V= 1931.5(8) (A)3, Dc =1.786 g/cm3, Mr = 519.49, λ(MoKα) = 0.71073 (A), μ = 1.853 mm-1, F(000) = 1048, R = 0.0464 and wR = 0.0918. A total of 2273 unique reflections were collected, of which 1570 with 1 ＞ 2σ(Ⅰ) were observed. The molecule of the complex has crystallographic mirror symmetry. The Zn atom is sixcoordinated in an octahedral geometry. In the crystal, the molecules are linked through intermolecular O-H…O and O-H…C1 hydrogen bonds, forming chains running along the a axis.     

Synthesis and Crystal Structure of Bisaqua-[N,N'-bis(3,5-dichlorosalicylidene)-1,3-diaminopropano]zinc(II)

1 INTRODUCTION N,N?-Bis(salicylidene)-1,3-diaminopropane (BSDP) is a versatile tetradentate ligand, which forms stable complexes with a large number of transition metals[1～3]. However, the complexes related to the BSDP deriva- tive,N,N?-bis(3,5-dichlorosalicylidene)-1,3-diamino- propane (BCDP), have been seldom reported. The prime interest in these complexes is their ability to afford functional solid materials with potentially controllable properties and novel molecular struc- tur…     

Metal derivatives of 1,3-bis(2-pyridyl)-1,3-propanedione and N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione

Complexes of transition metal ions with the oxygen-nitrogen containing ligand 1,3-bis(2-pyridyl)-1,3-propanedione (bpypH) have been synthesized. These present stoichiometries which do not conform with the usual tendency manifested by β-diketones, since molecular formulas with the composition M(bpyp)X are found. A nitrogen methylated ligand N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione methyl sulphate [dimebpypH] (MeSO₄)₂ has also been synthesized and its complexes with transition metal ions studied. The stoichiometries now, resemble those of typical β-diketones, namely [dimepyp]₂MX₄ with four anions because of the dicationic nature of the original ligand. This, together with IR evidence suggests a dual type of coordination by bpip via the β-diketone and the pyridyl moieties.     

Complexation between decamethyl-3,3′-bis(dipyrrolylmethene) and zinc(II), copper(II), and cobalt(II) acetates

Decamethyl-3,3′-bis(dipyrrolylmethene) dihydrobromide H₂L · 2HBr (H₂L is bis(3,4,7,8,9-pentamethylpyrrol-3-yl)methane), which is the simplest representative of a novel class of oligo(dipyrrolylmethenes) belonging to chromophore chelating nonmacrocyclic ligands, were examined by ¹H NMR, IR, and electronic absorption spectroscopy. Complexation reactions of H₂L · 2HBr with M(AcO)₂ (M = Zn(II), Cu(II), and Co(II)) in DMF at 298.15 K were monitored by electronic absorption spectroscopy and studied by the molar ratio method. The thermodynamic constants K ⁰ of these reactions were estimated. The d metal ions coordinate H₂L to give the binuclear homoleptic complexes [M₂L₂]. The reactions proceed through the intermediate binuclear heteroleptic complex [M₂L(AcO)₂] detected by spectroscopic methods. The thermodynamic stabilities of [M₂L₂] and [M₂L(AcO)₂] increase when moving from Cu(II) to Zn(II) and Co(II). The probability of formation and stability of [M₂L₂] containing 3,3′-bis(dipyrrolylmethene) are substantially higher than those of analogous complexes with the 2,2′-isomer (decamethyl-2,2′-biladienea, c). The low K ⁰ values for the complexation between H₂L and Cu(AcO)₂ are due to slow oxidation of the biladiene ligand into a bilatriene with participation of Cu²⁺ ions.     

Bis-(tetraethylammonium)[tetraazidocuprate(II)] and catena-di-μ-1,1-azido-[di-μ-1,1-azido-bis-(2,4-dimethylpyridine)dicopper(II)]

Two new copper(II) azido complexes, namely bis-(tetraethylammonium)[tetraazidocuprate(II)] (1) and catena-di--1,1-azido-[di--1,1-azido-bis-(2,4-dimethylpyridine)dicopper(II)] (2), have been prepared and characterized by spectroscopic and crystallographic methods. Complex (1) consists of isolated NEt⁺ ₄ cations and [Cu(N₃)₄]^2– anions. The site symmetry around the copper atom in the anion is 4/m. Complex (2) features a 1 D chain structure, five coordinated square pyramidal copper(II) atoms with both azides functioning as -1,1-bridges. The i.r. spectra reveal that both complexes contain asymmetric azido ligands. The solid and solution electronic spectra of (1) and (2) show very strong absorption bands in the visible region associated with N^– ₃ Cu^II charge-transfer transitions. The e.p.r. spectra of powder samples and solutions at room temperature were recorded and discussed.     

Bis[2-(4′-Bromopyrazolyl-1′)-3-Tosylaminopyridinato]zinc(II): Synthesis,structure, and luminescence properties

2-(4′-Bromopyrazolyl-1′)-3-tosylaminopyridine (HL³) and its complex ZnL₂ (I) are synthesized, and their structures are studied by IR, UV, and ¹H NMR spectroscopy. The molecular structure of complex ZnL₂ is determined by X-ray diffraction analysis. The atomic structure of ZnL₂ is confirmed by the optimization of the molecular geometry using quantum-chemical calculations in the density functional theory approximation. The experimental bands in the absorption spectrum of complex I are interpreted on the basis of the calculations, and its photoluminescence properties are studied.     

Spectroscopy of the excited-state complex of zinc(II) with 3,3′-bis(dipyrrolylmethene)

Spectra of nonstationary transient absorption of metal bis(dipyrrolylmethene) complexes in cyclohexane and ethanol, which exhibit different photophysical and photochemical properties in these solvents, have been measured and the yields of excited triplet states have been evaluated. It has been shown that the yield of triplets is determined by the intramolecular structure and the difference in fluorescence and phototransformation yields is due to intermolecular interaction of the excited molecules with the solvation shell.     

Structure and Photosynthetic Mimicking of Bis(2,6-bis(benzimidazol-2-yl)pyridine)manganese(II)

Introduction　　Manganeseionsplayanimportantroleinthelight in ducedoxidationofwatertomolecularoxygeninphotosys temII (PSII)ofgreenplants.1 3Inrecentyears ,man ganesecomplexesofpolypyridineligands ,suchasbipyri dine ,1,10 phenanthrolineand 2 ,2′:6′,2″ terpyridine ,havehadconsiderableattentionasthecomplexesformedareusefulmodelsformanganese containingbimolecu lars .4 6 Therefore ,synthesisandcharacterizationofman ganeseinitsvariousoxidationstates ,withvariousligandtypesandnuclearities ,hav…     

meso-spacer influence on properties of zinc(II) complexes with 2,3′- and 3,3′-bis(dipyrrolylmethenes)

The study and comparative analysis of spectral-luminescent characteristics (absorption and fluorescence spectra), of quantum yield, and fluorescence life time in solutions, of lability in proton-donor media, solid phase thermal stability in air oxygen and argon was carried out for binuclear zinc(II) helicates with decamethyl-substituted 2,3′- and 3,3′-bis(dipyrrolylmethenes). The influence of molecular structure features of the ligands on the physicochemical properties of helicates was discussed.     

Synthesis and Structure of bis(μ-2-aminopyridine N-oxide)-bis[dichlorocopper(II)]

1 INTRODUCTIONMany complexes of 2-aminopyridine N-oxide (apo) have been characterized by infrared spectra, X-ray powder diffraction spectra, and by magnetic measurements and electronic spectra at liquid nitrogen temperature, but very few of them are their crystal X-ray studies[1~3]. Recently, a number of bridged binuclear copper (II) complexes have been reported, some of which have important potential applications in bioinorganic chemistry and materials[4~6]. Particularly, the complexes …     

[Bis(trispivalatodimolybdenum (II))-μ-bis(4′-carboxylato-2,2′:6′,2″-terpyridine) ruthenium (II)] (2+) Tetrafluoroborate: Photophysical Studies

The photophysical properties of the title compound have been studied by fs and ns transient absorption spectroscopy. The electronic absorption spectrum consists of three principle absorptions assigned to terpy ¹LLCT at ~300 nm, ruthenium (II) t_2g⁶ to terpy ¹MLCT at ~470 nm and Mo₂ δ to terpycarboxylate at ~670 nm. The compound shows weak room temperature emission in THF solution at ~1,100 nm when excited into each of the aforementioned bands. This emission is assigned to the T₁ state, ³MMδδ*. Transient absorption spectroscopy indicates a lifetime for T₁ of 9.6 μs. This paper is dedicated to Prof. C. N. R. Rao.     

Synthesis and Crystal Structure of Bis[2-[2-(diethylamino)ethyliminomethyl]-4-nitrophenolato]dimethanolcobalt(II) Dinitrate

1 INTRODUCTION The significance of cobalt coordination com- pounds in biological systems is recognized[1～3]. In many instances the cobalt coordination compounds of Schiff bases have been suggested as models to describe energy transfer in naturally occurring systems. In such cases the coordination sphere about the metal ion is believed to play an important role in determining the nature of the model system[4, 5]. In order to investigate the structures of such complexes, we report herein t…     

Synthesis and Crystal Structure of Bis(μ-bis(diphenyl-phosphino)methane)(μ-benzenethiolate)(acetonitrile)Dicopper(I) Perchlorate Diethylether Solvate

The reaction between [Cu2(μ-dppm)2(MeCN)4](ClO4)2(dppm=bis(diphenylphos-phino)methane) and [Zn(PhS)2(bpy)] (bpy=2,2'-bipyridine,PhS=benzenethiolate) gave the complex [Cu2(μ-dppm)2(μ-PhS)(MeCN)]ClO4·0.5(Et2O)(C58H52ClNO4P4SCu2·0.5Et2O) which was determined by X-ray single-crystal diffraction.The crystal is of orthorhombic,space group P212121 with a=13.6157(3),b=20.8022(6),c=21.3299(6)A,V=6041.4(3) A3,Mr=1182.54,Dc=1.300 g/cm3,F(000)=2444,μ=0.934 mm-1 and Z=4.The final R=0.0773 and wR=0.1843 for 7744 observed reflections (I>2σ(I)).The dicopper atoms are doubly bridged by dppm as well as one S donor from benzenethiolate.One copper atom is in a distorted trigonal bipyramidal environ- ment,whereas the other adopts a distorted tetrahedral geometry.