Crystal structure of the 1:1 guest-host complex of bis(hexafluoroacetylacetonate)barium with 18-crown-6

X-ray diffraction structural analysis.     

Synthesis and structure of dimeric bis(isothiocyanato)tris (4-methylpyridine)nickel (II)

Summary The Ni₂(NCS)₄(4-Methylpyridine)6 complex has been prepared crystalline from methanolic solutions of Ni(NCS)2(4-Methylpyridine)4. Three dimensional x-ray diffraction data were collected by means of an automated single crystal diffractometer. The structure was solved by Patterson methods and refined to a final R value of 0.075, based on 2422 observed_ reflections. The compound crystallizes in space group P1 with one dimeric molecule in a unit cell of dimensions a = 10.57(1), 6 = 14.06(1), c = 8.66(1) Å, = 105.2(1), = 114.8(1), y = 95.6(1)°. The Ni atoms have distorted octahedral coordination with one sulfur and five nitrogen atoms - two of the four thiocyanate groups form a double bridge between the neighbouring Ni atoms.4-MePy = 4-Methylpyridine     

Saturation vapor pressure of the mixed-ligand calcium bis(hexafluoroacetylacetonate) complex with dyglime and water

The vapor composition and thermodynamic characteristics of vaporization of the mixed-ligand complex Ca(hfa)₂(diglyme)(H₂O) (I) (hfa^? is the hexafluoroacetylacetonate anion, diglyme is 1-methoxy-2-(2-methoxyethoxy)ethane) in the temperature range of 298–350 K were studied by the Knudsen effusion method with mass-spectrometric analysis of the gas phase. The mass spectrometry data were juxtaposed with the results of thermal analysis. It was shown that dehydration of I, resulting in a change of the intermolecular bonding system, affects the thermodynamic parameters of sublimation under conditions where dehydration and sublimation occur in parallel.     

Synthesis,crystal structure and magnetic property of bis(tetra-n-butylammonium) bis(4,5-dicyanobenzene-1,2-dithiolato) oxovanadium complex

The bis(dithiolene) oxovanadium complex, namely (n-Bu₄N)₂[(dcbdt)₂VO] (dcbdt = 4,5-dicyanobenzene-1,2-dithiolato), was unprecedentedly obtained from the reaction of Na₂dcbdt and vanadium trichloride. An X-ray structure analysis indicated that [(dcbdt)₂VO] moieties are surrounded by n-Bu₄N cations and there was no direct interaction among these moieties. Although there was no direct interaction among them, several S⋯H, C⋯H and N⋯H van der Waals contacts between n-Bu₄N cations and [(dcbdt)₂VO] moieties were observed. The ESR and SQUID measurement showed that the vanadium atom is in the state of V(IV) (S = 1/2) and these magnetic moments interact with each other very weakly antiferromagnetically (θ = -0.371 K).     

A novel dimeric zinc(II) complex with a tripodal peptide ligand: a structure stabilized by ligand sharing

The crystal structure of a novel dimeric zinc(II) complex, [ZnL(H₂O)]₂(ClO₄)₂·4H₂O (L?=?N-(bis(2-pyridyl)methyl)-2-pyridinecarboxamide), has been determined by X-ray diffraction. In this complex each planar N_py–N_amido–N_py moiety of the ligand coordinates to one zinc ion and the pendant pyridine of one [ZnL] unit completes the coordination sphere of a [ZnL] neighbor. Units of the complex are connected in a two-dimensional network by intermolecular hydrogen bonds. The thermodynamic properties of the ligand with bivalent metal ions Co(II), Ni(II), Cu(II) and Zn(II) were studied by potentiometric titration and the order of the stability constants is in agreement with the Irving–Williams series. The dimeric complex is stabilized through ligand sharing, as confirmed by the crystal structure and thermodynamic properties.     

A novel dimeric complex of dysprosium with pyridine-3-carboxylic acid: structure and photophysical properties

A dimeric complex [Dy(NIC)₃(H₂O)₂]₂ (HNIC = pyridine-3-carboxylic acid) has been synthesized. X-ray analysis reveals that it forms a novel dimeric structure through bridged oxygen atoms of carboxylate groups. The title complex crystallizes in space group P2₁/c, with a = 9.560(3), b = 11.601(4), c = 17.731(5)?Å, β = 91.572(4)°, V = 1965.7(10)?ų, D _c = 1.909?Mg/m³, Z = 2, F(000) = 1100, GOF = 0.956, R ₁ = 0.0248. Photophysical properties have been studied with ultraviolet absorption, excitation and emission spectra. The complex exhibits strong blue emission.     

A novel Cd(II) complex with 1,3-bis(4-Pyridyl)propane: Synthesis,crystal structure,and interaction with DNA

The complex [Cd(Bpp)₃Cl₂] _n · 2H₂O (Bpp = 1,3-bis(4-pyridyl)propane) has been synthesized and characterized by elementary analysis, IR spectrum and singel-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group C2/c with the crystal cell parameters of a = 31.05(3), b = 17.556(13), c = 16.281(13) Åβ = 121.402(7)°, V = 7574(10) ų, and Z = 8. The compound has formed a 1D surface shape structure through these coordinate modes with the ligand. The 2D layers are further aggregated by hydrogen bonding with octameric subunits.     

Synthesis, structure, and magnetic properties of an antiferromagnetic spin-ladder complex: bis(2,3-dimethylpyridinium) tetrabromocuprate

The complex (2,3-dmpyH)2CuBr4 has been synthesized and its crystal packing determined by single-crystal X-ray diffraction (2,3-dmpyH = 2,3-dimethylpyridinium). The compound crystallizes in the triclinic space group P1. The crystal packing is characterized by the formation of a ladder structure for the CuBr4 anions showing short Br...Br contacts. The rungs of the ladder are formed via a crystallographic inversion center, while the rails are formed via unit cell translations. Variable temperature magnetic susceptibility measurements agree very well with the ladder model [Jrung = -3.10 cm-1 (-4.34 K) and Jrail = -6.02 cm-1 (-8.42 K)]. The assignment as a magnetic ladder is confirmed by first principles bottom-up theoretical calculations which conclude that Jrung = -3.49 cm-1 (-4.89 K) and Jrail = -7.79 cm-1 (-10.9 K), in very good agreement with the experimental values. They also support the absence of additional significant magnetic exchange within the crystals. Thus, (2,3-dmpyH)2CuBr4 represents the second reported example of a weak-exchange limit magnetic ladder (that is, one in which the exchange along the rail is stronger than that across the rung).     

A vanadium(V) complex with a tetradentate [OSSO]-type bis(phenolato) ligand: Synthesis,structure, and ethylene polymerization activity

Reaction of VOCl₃ with racemic trans-1,2-dithiacyclohexanediyl-2,2′-bis(6-tert-butyl-4-methylphenol) affords the chiral-at-metal vanadium(V) complex [V{(C₆H₂O-6-tert-Bu-4-Me)₂S₂C₆H₁₀}OCl] (1). The molecular structure of 1 was established by single crystal X-ray diffraction, which shows a cis-α configuration of the ligand around the vanadium center. Upon activation with MAO, 1 was found to be a highly active catalyst for the polymerization of ethylene, but was not active in the polymerization of propene and styrene. The influence of temperature and cocatalyst ratio on polymerization activity was studied.     

Synthesis, structure, and properties of a dimeric chromium(II) pyrazolato complex with a long chromium-chromium distance. Maintenance of a dimeric structure in solution and interconversion between dimeric and monomeric structures

The synthesis, solid-state structure, and solution structure of Cr2(tBu2pz)4 are described. This complex is obtained by sublimation of the monomeric species Cr(tBu2pz)2(4-tBupy)2 and contains long chromium-chromium distances that are enforced by the divergent nature of the pyrazolato ligands.     

Thermally induced magnetic anomalies in solvates of the bis(hexafluoroacetylacetonate)copper(II) complex with pyrazolyl-substituted nitronyl nitroxide

We succeeded in synthesizing of a whole family of isostructural solvates of the copper(II) hexafluoroacetylacetonate complex with pyrazolyl-substituted nitronyl nitroxide (L): Cu(hfac)2L x 0.Solv. The main feature inherent in nature of Cu(hfac)2L x 0.5 Solv single crystals is their incredible mechanical stability and ability to undergo reversible structural rearrangements with temperature variation, accompanied by anomalies on the mu(eff(T)) dependence. Structural investigation of the complexes over a wide temperature range before and after the structural transition and the ensuing magnetic phase transition showed that the spatial peculiarities of the solvent molecules incorporated into the solid govern the character of the mu(eff(T)) dependence and the temperature region of the magnetic anomaly. Thus, doping of crystals with definite solvent molecules could be used as an efficient method of control over the magnetic anomaly temperature (T(a)). The investigation of this special series of crystals has revealed the relationship between the chemical step and the magnetic properties. It was shown that "mild" modification of T(a) for Cu(hfac)2L x 0.5 Solv required a much smaller structural step than the typical change of one -CH2- fragment in a homologous series in organic chemistry. Quantum-chemical calculations with the use of X-ray diffraction data allowed us to trace the character of changes in the exchange interaction parameters in the range of the phase transition. In the temperature range of the phase transition, the exchange parameter changes substantially. The gradual decrease in the magnetic moment, observed in most experiments during sample cooling to T(a), is the result of the gradual increase in the fraction of the low-temperature phase in the high-temperature phase.     

A novel tetranuclear copper(I) sulfanide complex with bis(diphenylphosphino)amine

The title novel mixed μ₂‐SH‐ and μ₃‐SH‐bridged tetranuclear copper(I) complex, cyclo‐bis[μ₂‐bis(diphenylphosphino)amine]di‐μ₃‐sulfanido‐di‐μ₂‐sulfanido‐tetracopper(I) methanol disolvate, [Cu₄(SH)₄(C₂₄H₂₁NP₂)₂]·2CH₃OH, has crystallographically imposed centrosymmetry and affords a neutral Cu₄S₄ core with a distorted step‐like structure. The distances of 2.8458 (16) and 2.8179 (16) Å between copper(I) centres indicate the presence of ligand‐supported Cu...Cu interactions. Strong N—H...O and O—H...S hydrogen bonds between the tetranuclear cluster and methanol solvent molecules result in a two‐dimensional hydrogen‐bonded supramolecular network. This complex is the first example of a coinage tetranuclear metal complex with mixed μ₂‐SH‐ and μ₃‐SH‐bridged chromophores.     

Synthesis,crystal structure and electronic properties of bis(N-2-bromophenyl-salicydenaminato)copper(II) complex

A new series of complexes of the type bis(N-substituted-salicydenaminato)copper(II) (1–9), have been synthesized and characterized by IR, UV–Vis and elemental analysis methods. The molecular structure of bis(N-2-bromophenyl-salicydenaminato)copper(II) (6), was determined using X-ray crystallography. There are two independent molecules in the structure. Each shows a neutral, mononuclear, four-coordinate, square-planar trans-Cu[N₂O₂] geometry and, in each, the Cu atom and the ligating atoms are coplanar. The chelating N–Cu–O angle is 91.39(11)° for molecule one and 91.20(11)° for molecule two, whereas the non-chelating N–Cu–O angles are 88.61(11) and 88.80(11)°, respectively. The trans-N–Cu–N and trans-O–Cu–O bond angles are 180°. The electronic absorption spectra of copper(II) complexes (1–9), indicate that the d–d band energy is dependent on the nature and position of substituent on phenyl ring of the salicyldenimine ligand. The UV–Vis spectra in various solvents were measured and a relationship between absorption spectra and dielectric constant of the solvents is reported.     

A novel water-rich mononuclear copper(II) complex with pyridine-2,4-dicarboxylate: Synthesis and crystal structure

A new monomolecular copper(II) complex, [Cu(Phen)₂(Pda)] · 9H₂O (I) (H₂Pda = pyridine-2,4-dicarboxylate acid, Phen = 1,10-phenanthroline), has been prepared from H₂Pda and Phen at room temperature and characterized by IR, elemental analysis, X-ray powder diffraction, and single-crystal X-ray diffraction. Structure analysis shows that each Cu(II) is coordinated by two Phen ligands and one Pda ligand to complete a octahedron CuN₅O chromophore. In addition, a unique water networks paralleling to (001) composed by the crystallization water through hydrogen bonds play a important role in the stability of crystal structure. The crystal structure is found to be orthorombic with space group Pbcn and cell parameters a = 13.651(4), b = 22.516(7), c = 22.386(7) Å, R ₁ = 0.0735 and wR ₂ = 0. 0.1935.     

双大环配体与铜双核配合物的合成、晶体结构和磁偶合性质

由新型双功能配体2,6-双(1,5,9-三氮杂环十二烷)-2,6-二甲基苯甲酸(L)与溴化铜在甲醇中反应得到新型铜双核配合物[Cu~2LBr~2]Br.3H~2O单晶。晶体结构分析表明:2个Cu(II)中心离子由配体L中的羧酸基团桥联;2个等价的Cu(II)中心离子均由双功能配体L的1,5,9-三氮杂环十二烷([12aneN~3)的3个氮原子和羧酸的1个氧原子及1个Br^-离子配位,并都处在三角双锥的配位环境中;分子内Cu...Cu双核间的距离为0.5884(6)nm。变温磁化率数据表明:在同一分子中的2个铜核之间存在反铁磁偶合作用(J=-22.49cm^-^1)。     

Synthesis,structure and optical properties of a CoII complex with bis(2,4,7,8,9-pentamethyldipyrrolylmethen-3-yl)methane

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A new luminescent sulfate bridged dimeric copper(II) complex with DNA binding and SO2 fixation ability: Synthesis and structure

New luminescent mononuclear and dinuclear copper(II) (S = 1/2) complexes [Cu(HL)(H₂O)₂](ClO₄)₂ (1a) and [Cu₂(HL)₂(μ-SO₄)₂]·2H₂O (1b) were synthesized with the acyclic tridentate pyridine-2-carboxaldehyde-2-pyridylhydrazone ligand, HL (1). Interestingly, the mononuclear complex 1a can be converted into the disulfate bridged dimeric copper(II) complex 1b by passing freshly prepared SO₂ through the basic medium. On excitation at 290 nm, the ligand fluoresces at 364 nm due to an intraligand ¹(π–π1) transition. Upon complexation with copper(II), the emission peak is slightly blue shifted (356 nm, F/F₀ 0.76 for 1a and 354 nm, F/F₀ 0.89 for 1b) with a little quenching in the emission intensity. The association constants (K_ass (5.06 ± 0.004) × 10⁴ for 1a and K_ass (5.46 ± 0.006) × 10⁴ for 1b at 298 K) and the thermodynamic parameters have been determined by UV–Vis spectroscopy. The molecular structure of the complex 1b (Cu?Cu 4.456 Å) has been determined by single crystal X-ray diffraction studies. The complex 1b exhibits a strong interaction towards DNA as revealed from the K_b (intrinsic binding constant) 6.3 × 10⁴ M^?1 and K_sv (Stern–Volmer quenching constant) 2.93 values.