Synthesis and crystal structure of π complex of copper(I) chloride with diallyl trisulfide 2CuCl · DATrS

Crystals of the π complex 2CuCl·DATrS (DATrS = diallyl trisulfide) were prepared by ac electrochemical synthesis and studied by X-ray diffraction. The crystals are monoclinic, space group C2, Z = 2, a = 12.737(1) Å, b = 5.0984(5) Å, c = 8.9263(7) Å, β = 101.159(5)°, V = 568.72(8) ų. The structure contains infinite coils of (CuCl)_n, which are united into a three-dimensional structure by the bibridge tetradentate ligand DATrS symmetric to axis 2. The trigonal-pyramidal surrounding of the Cu atom consists of two Cl atom, the olefine C=C group, and the S atom (in the apical position) of different DATrS molecules.     

Vibrational study of diphenylphosphorus halides Ph2PX (X  Cl,Br, I)

The Raman and i.r. spectra of diphenylphosphorus halides, Ph₂PX (X  Cl, Br, I), have been measured and concerted assignments have been made confirmed by an approximate normal coordinate analysis for the skeletal vibrations of Ph₂PCl using a three mass model for the phenyl group.     

Syntheses,crystal structures and magnetic properties of two cyano-bridged copper(I)–copper(II) mixed-valence complexes

Two cyano-bridged copper(II)–copper(I) mixed-valence assemblies, Cu(EAM)₂[Cu(CN)₂]₂ 1 (EAM?=?ethanolamine) and Cu(DETA)[Cu(CN)₂]₂·0.5H₂O 2 (DETA?=?diethylenetriamine), have been prepared and structurally and magnetically characterized. IR spectra indicate the presence of bridging cyano groups in both 1 and 2, confirmed by structure analyses; Cu(I)–CN–Cu(II), Cu(I)–CN–Cu(I) and Cu(I)–Cu(I) metal bond linkages are evident. In the lattice, a 3D network is formed by two [Cu(CN)₂]?^? units and one [Cu(EAM)₂]²⁺unit for 1. Variable temperature magnetic susceptibilities, measured in the 5–300?K range, indicate weak antiferromagnetic exchange interactions in complex 1.     

Dimeric and polymeric copper(I) complexes. Synthesis and characterization of copper(I) complexes of di-2-pyridyl ketone oxime (DPKox) and crystal structures of [Cu(DPKox)Cl]2·2H2O and [Cu(DPKox)(NCS)]n

Copper(I) complexes with di-2-pyridylketone oxime (DPKox) of the type CuLX·nH₂O, n=1 for X=Cl and Br, and n=0 for X=I and SCN, have been synthesized and characterized. The overall physical results suggest tridentate and bidentate DPKox ligand in the Cl, Br and I, SCN complexes, respectively, and terminal X in the former but bridging X in the later. These complexes display MLCT bands in the visible region, but they do not fluoresce at room temperature. The structure determination has shown the chloride complex (1) to have a centro-symmetrically related dimeric unit, in which each copper atom is coordinated by Cl(1), N(1), N(2) and N(3) (of the second ligand molecule) in a distorted tetrahedral environment. Hydrogen bonds are formed by the O(1) of the oxime group and a lattice water molecule, and between different lattice water molecules and Cl(1). The structure of the thiocyanate complex (2) features tetrahedral geometry around copper atoms, a chelating bidentate DPKox ligand coordinating via one of the two pyridyl nitrogens, N(1), and N(oxime) only and μ-1,3-thiocyanate group forming zigzag chains along the c-axis of the unit cell.     

Photoelectron Spectroscopy and Structures of X−⋅⋅⋅CH2O (X=F,Cl, Br,I) Complexes

A combined experimental and theoretical approach has been used to investigate X⁻⋅⋅⋅CH₂O (X=F, Cl, Br, I) complexes in the gas phase. Photoelectron spectroscopy, in tandem with time-of-flight mass spectrometry, has been used to determine electron binding energies for the Cl⁻⋅⋅⋅CH₂O, Br⁻⋅⋅⋅CH₂O, and I⁻⋅⋅⋅CH₂O species. Additionally, high-level CCSD(T) calculations found a C_2v minimum for these three anion complexes, with predicted electron detachment energies in excellent agreement with the experimental photoelectron spectra. F⁻⋅⋅⋅CH₂O was also studied theoretically, with a C_s hydrogen-bonded complex found to be the global minimum. Calculations extended to neutral X⋅⋅⋅CH₂O complexes, with the results of potential interest to atmospheric CH₂O chemistry.     

Complexes of group IIb metals with dithio oxamides—II. Vibrational analysis of ZnLX2(X = Cl,Br, I) complexes

With dithiooxamides, Zn(II) in acid media forms distorted tetrahedral complexes, which behave as non-electrolytes. The ligands act as bidentates with S, S coordination.A thorough vibrational analysis has been performed for the Zn(CH₃ NHCSCSNHCH₃)X₂(X = Cl, Br, I) and for the Zn[(CH₃)₂NCSCSN(CH₃)₂]X₂(X = Cl, Br, I) complexes.     

N-H…X (X = F, Cl, Br, and I) hydrogen bonding in aromatic amide derivatives in crystal structures

Intramolecular N H···X (X=F, Cl, Br, and Ⅰ) hydrogen bonding patterns of aromatic amides in the solid state are summarized. It is revealed that the key for the formation of this kind of weak intramolecular hydrogen bonding in X-ray crystal structures is to suppress the competition of strong intermolecular N H···O C hydrogen bonding of the amide unit. For amides with identical backbones, the bonding capacity of halogen atoms as hydrogen bonding acceptors is in the order of F>Cl>Br>I, which is in accordance with their electronegativity strength. Generally, the five-membered hydrogen bonding is easier to form than the six-membered one.     

Communication: probing the entrance channels of the X+CH4→HX+CH3 (X = F, Cl, Br, I) reactions via photodetachment of X(-)-CH4

The entrance channel potentials of the prototypical polyatomic reaction family X + CH(4) → HX + CH(3) (X = F, Cl, Br, I) are investigated using anion photoelectron spectroscopy and high-level ab initio electronic structure computations. The pre-reactive van der Waals (vdW) wells of these reactions are probed for X = Cl, Br, I by photodetachment spectra of the corresponding X(-)-CH(4) anion complex. For F-CH(4), a spin-orbit splitting (～1310 cm(-1)) much larger than that of the F atom (404 cm(-1)) was observed, in good agreement with theory. This showed that in the case of the F-CH(4) system the vertical transition from the anion ground state to the neutral potentials accesses a region between the vdW valley and transition state of the early-barrier F + CH(4) reaction. The doublet splittings observed in the other halogen complexes are close to the isolated atomic spin-orbit splittings, also in agreement with theory.     

Structure of Complexes Formed in the CuX2–Cu–N-Allylisoquinolinium Chloride System (X = Cl,Br)

The crystals of N-allylisoquinolinium chlorides of the compositions [C₉H₇N(C₃H₅)]₂Cu^IICl₄ (I), [C₉H₇N(C₃H₅)]Cu^ICl₂ · H₂O (II), and [C₉H₇N(C₃H₅)]Cu^ICl_1.43Br_0.57 · H₂O (III) were prepared by alternating-current electrosynthesis. X-ray diffraction analysis (using diffractometer models DARCH1 for I, STOE for II, and KUMA/CCD for III, MoK radiation) showed that the crystals of I are monoclinic, space group P2₁/n, a = 14.91(1) Å, b = 10.41(1) Å, c = 16.90(1) Å, = 109.73(8)°, V = 2470(8) ų, Z = 4. The crystals of isostructural compounds II and III are triclinic, space group P, Z = 2; crystals II: a = 7.2446(6) Å, b = 7.4379(6) Å, c = 12.110(1) Å, = 80.95(1)°, = 85.55(1)°, = 86.60(1)°, V = 641.8(2) ų; crystals III: a = 7.253(2) Å, b = 7.459(4) Å, c = 12.151(5) Å, = 80.82(4)°, = 83.73(3)°, = 86.81(4)°, V = 644.6(9) ų. The structure of I is composed of Cu^IICl₄ ^2– tetrahedra and N-allylisoquinolinium cations united by C–H···Cl hydrogen bonds in corrugated layers. The crystal structures of -complexesII and III are built of [C₉H₇(C₃H₅)]₂Cu₂ ^IX₄ dimers, which form layers along the c axis due to the C–H···X hydrogen bonds. An important role in the structure formation is played by water molecules, which crosslink the organometallic layers to form a three-dimensional framework through the O–H···X contacts.     

Pressure-induced formation of molecular B2X4(μ-X)2 (X = Cl, Br, I) species

Boron(III) halides (BX(3), where X = F, Cl, Br, I) at ambient pressure conditions exist as strictly monomeric, trigonal-planar molecules. Using correlated ab initio calculations, the three heavier halides (X = Cl, Br, I) are shown to possess B(2)X(4)(μ-X)(2) local minima, isostructural with the diborane molecule. The calculated dissociation barrier of the B(2)I(4)(μ-I)(2) species [≈14 kJ/mol with CCSD(T)/cc-pVTZ] may be high enough to allow cryogenic isolation. The remaining dimer structures are more labile, with dissociation barriers of less than 6 kJ/mol. All three dimer species may be stabilized by application of external pressure. Periodic density functional theory calculations predict a new dimer-based P1 solid, which becomes more stable than the P6(3)/m monomer-derived solids at 5 (X = I) to 15 (X = Cl) GPa. Metadynamics simulations suggest that B(2)X(4)(μ-X)(2)-based solids are the kinetically preferred product of pressurization of the P6(3)/m solid.     

Pyridine-based complexes of copper(II) chloride and bromide: ligand conformation effects on crystal structure. Synthesis,structure and magnetic behavior of Cu(2-Cl-3-X′py)2X2 [X,X′ = Cl,Br]

Abstract

Reaction of copper(II) chloride or bromide with 2-chloro-3-bromopyridine or 2,3-dichloropyridine generates a family of compounds of the general formula L₂CuX₂ (1–4). X-ray crystallography shows that the bromide complexes (3-bromo-2-chloropyridine)dibromidocopper(II) (1) and (2,3-dichloropyridine)dibromidocopper(II) (3) are particularly unusual in that they crystallize with both the syn- and anti-conformation structures in the same crystal. A review of the literature on complexes of the formula (substituted-pyridine)₂CuX₂ suggests that these are the first examples of such complexes. The members of the family show a variety of magnetic behaviors and variable temperature magnetic susceptibility data indicate that 1 is essentially paramagnetic (θ = ?0.9(1) K) while 3 is weakly ferromagnetic (J?=?2.9(1) K). Compound 2 [(3-bromo-2-chloropyridine)dichloridocopper(II)] is fit by the uniform 1-D antiferromagnetic model (J = ?19.6(1) K), while 4 [(2,3-dichloropyridine)dichloridocopper(II)] exhibits weak anti-ferromagnetic interactions (J = ?3.68(3) K).     

Syntheses and crystal structures of mixed-ligand copper(II)–imidazole–carboxylate complexes

The syntheses, characterization, and crystal structures of the reaction products of Cu²⁺ with imidazole (Himz) and different aromatic carboxylates, viz.: [Cu(Himz)₂(cinn)₂(H₂O)] (1), [Cu(Himz)₂(paba)₂] (2) and [Cu(Himz)₂(clba)₂] (3) (cinn^– = C₉H₇O₂^–, paba^– = C₇H₆NO₂^–, clba^– = C₇H₄ClO₂^–) are described and studied by spectroscopic (UV–visible, FTIR) measurements. Single-crystal X-ray diffraction analyses indicate that each complex is monomeric. The metal ion in 1 adopts square-pyramidal coordination geometry arising from two imidazole nitrogens, two cinnamate oxygens, and an apical aqua. The metal ions of 2 and 3, however, assume a square planar configuration, which is realized by coordination of two nitrogens of two imidazoles and two oxygens; in both complexes, the imidazole moieties are trans to each other. TGA results indicate that upon heating, these complexes lose their carboxylate anions first, followed by removal of the imidazole molecules.     

Synthesis,crystal structures and Jack bean urease inhibitory activity of copper(II) complexes with 4-bromo-N′-(2-hydroxy-5-methoxybenzylidene)benzohydrazide

A new hydrazone 4-bromo-N′-(2-hydroxy-5-methoxybenzylidene)benzohydrazide (HL) was prepared and characterized by infrared and UV–vis spectra, as well as single-crystal X-ray diffraction. With the hydrazone as ligand, two new copper(II) complexes were prepared, [Cu₂L₂(NCS)₂]·4H₂O (1) and [CuBrL]·CH₃OH (2). The complexes were characterized by infrared and UV–vis spectra, and single-crystal X-ray diffraction. The Cu in 1 is in a square pyramidal coordination geometry and that in 2 is in a square planar coordination geometry. The two complexes show effective Jack bean urease inhibitory activity, with IC₅₀ values of 23.5 and 2.7 μM, respectively. A molecular docking study of 2 with the urease was performed. The relationship between the structure and urease inhibitory activity indicated that copper complex with square planar coordination is a better model for urease inhibition.     

Copper(I) halide complexes with a sterically hindered thiourea: synthesis and crystal structures of [Cu(dchtu)2Cl] and [Cu(dchtu)2Br] (dchtu = N,N ′-dicyclohexylthiourea)

Copper(I) complexes with a sterically hindered thiourea, [Cu(dchtu)₂X] (dchtu = N,N′-dicyclohexylthiourea; X=Cl 1, Br 2), were synthesized and their crystal structures were determined. Compounds 1 and 2 are isostructural orthorhombic, space group P2₁2₁2₁. Crystallographic data for 1 : a = 13.1711(13), b = 14.2610(19), c = 15.793(2) Å, V = 2966.4(6) ų, Z = 4. For 2 : a = 13.2628(13), b = 14.3410(19), c = 15.860(2) Å, V = 3016.5(6) ų, Z = 4. The stoichiometry of CuX complexes with thiourea is influenced by substituents on the nitrogens. Copper(I) halides only form bis-adducts with the sterically hindered dchtu ligand even with molar excesses of dchtu due to steric hinderance of the cyclohexyl substituents. In 1 and 2, the Cu(I) is trigonally coordinated by the sulfur atoms of two monodentate N,N′-dicyclohexylthiourea ligands and one halide. The structures of the complexes are stabilized by a system of intermolecular H-bonding.     

Importance of halogen···halogen contacts for the structural and magnetic properties of CuX2(pyrazine-N,N′-dioxide)(H2O)2 (X = Cl and Br)

The structural and magnetic properties of the newly crystallized CuX(2)(pyzO)(H(2)O)(2) (X = Cl, Br; pyzO = pyrazine-N,N'-dioxide) coordination polymers are reported. These isostructural compounds crystallize in the monoclinic space group C2/c with, at 150 K, a = 17.0515(7) ?, b = 5.5560(2) ?, c = 10.4254(5) ?, β = 115.400(2)°, and V = 892.21(7) ?(3) for X = Cl and a = 17.3457(8) ?, b = 5.6766(3) ?, c = 10.6979(5) ?, β = 115.593(2)°, and V = 950.01(8) ?(3) for X = Br. Their crystal structure is characterized by one-dimensional chains of Cu(2+) ions linked through bidentate pyzO ligands. These chains are joined together through OH···O hydrogen bonds between the water ligands and pyzO oxygen atoms and Cu-X···X-Cu contacts. Bulk magnetic susceptibility measurements at ambient pressure show a broad maximum at 7 (Cl) and 28 K (Br) that is indicative of short-range magnetic correlations. The dominant spin exchange is the Cu-X···X-Cu supersuperexchange because the magnetic orbital of the Cu(2+) ion is contained in the CuX(2)(H(2)O)(2) plane and the X···X contact distances are short. The magnetic data were fitted to a Heisenberg 1D uniform antiferromagnetic chain model with J(1D)/k(B) = -11.1(1) (Cl) and -45.9(1) K (Br). Magnetization saturates at fields of 16.1(3) (Cl) and 66.7(5) T (Br), from which J(1D) is determined to be -11.5(2) (Cl) and -46.4(5) K (Br). For the Br analog the pressure dependence of the magnetic susceptibility indicates a gradual increase in the magnitude of J(1D)/k(B) up to -51.2 K at 0.84 GPa, suggesting a shortening of the Br···Br contact distance under pressure. At higher pressure X-ray powder diffraction data indicates a structural phase transition at ～3.5 GPa. Muon-spin relaxation measurements indicate that CuCl(2)(pyzO)(H(2)O)(2) is magnetically ordered with T(N) = 1.06(1) K, while the signature for long-range magnetic order in CuBr(2)(pyzO)(H(2)O)(2) was much less definitive down to 0.26 K. The results for the CuX(2)(pyzO)(H(2)O)(2) complexes are compared to the related CuX(2)(pyrazine) materials.     

Copper(II) halide complexes of aminopyridines: Syntheses,structures and magnetic properties of [(5CAP)2CuX2] and [(5BAP)nCuX2] (X = Cl,Br)

Abstract

Reaction of 2-amino-5-halopyridine molecules with Cu(II) halides in the solid state via mechanochemical techniques produced four coordination complexes, (5BAP)₂CuBr₂ (2a), (5BAP)₂CuCl₂ (3), (5CAP)₂CuCl₂ (4), (5CAP)₂CuBr₂ (5) [5BAP?=?2-amino-5-bromopyridine; 5CAP?=?2-amino-5-chloropyridine]. In all compounds, the 5BAP or 5CAP ligands are coordinated to the Cu(II) ion through the pyridine N atom along with two halide ions. Compounds 2 and 3 crystallized in the P-1 and P2₁/c space groups, respectively. Temperature dependent magnetic susceptibility data for 2 were fit to the antiferromagnetic rectangle model (J?=?–4.5(2) K; α?=?0.89(17)), while the data for 3 were fit to the uniform chain model (J?=?–4.20(6) K), indicating a significant difference in the interchain interactions. Both 4 and 5 crystallize with the 5CAP ligands in the syn-conformation in the space groups I2/a and P21/n, respectively. Compound 4 formed the expected dimeric structure via bridging chloride ions and the magnetic data were successfully fit to the dimer model (J?=?–2.57(5) K), while 5 unexpectedly formed a structural chain via Br…Br contacts which exhibits very weak antiferromagnetic interactions. An intermediate structure, (5BAP)(H₂O)CuBr₂ (1), was prepared and characterized via mechanochemical methods along with an isomer of (5BAP)₂CuBr₂ (2b).     

Synthesis and properties of the copper(Ⅱ) complexes with stable radical

Four novel copper(Ⅱ) complexes have been synthesized,namely Cu(hfac)2NITPhNO2 (1),Cu(hfac)2NITPhCH3 (2),Cu(pfpr)2NITPhNO2,(3) and Cu(Pfpr)2NITPhCH3 (4),where hfac= hexafluoro-acetylacetonate,pfpr=pentafluoropropionate,NITR.=2-R-4,4,5,5-tetraniethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.(R=4-nitrophenyl,4-methylphenyl).These complexes were rharicter-ized by elemental analyses,IR,electronic spectra and molar conductance.The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4 300 K range,giving I he exchange integral J=10.56 cm-1 for complex 1 and J =-30.9 cm-1 for complex 3.