Bridging Chloride Anions Research Articles

Synthesis and crystal structure of poly[[μ-chlorido-μ-(2,3-di-methyl-pyrazine)-copper(I)] ethanol hemisolvate], which shows a new isomeric CuCl(2,3-di-methyl-pyrazine) network.

Reaction of copper(I)chloride with 2,3-di-methyl-pyrazine in ethanol leads to the formation of the title compound, poly[[μ-chlorido-μ-(2,3-di-methyl-pyrazine)-copper(I)] ethanol hemisolvate], {[CuCl(C6H8N2)]·0.5C2H5OH} n or CuCl(2,3-di-methyl-pyrazine) ethanol hemisolvate. Its asymmetric unit consists of two crystallographically independent copper cations, two chloride anions and two 2,3-di-methyl-pyrazine ligands as well as one ethanol solvate mol-ecule in general positions. The ethanol mol-ecule is disordered and was refined using a split model. The methyl H atoms of the 2,3-di-methyl-pyrazine ligands are also disordered and were refined in two orientations rotated by 60° relative to each other. In the crystal structure, each copper cation is tetra-hedrally coordinated by two N atoms of two bridging 2,3-di-methyl-pyrazine ligands and two μ-1,1-bridg-ing chloride anions. Each of the two copper cations are linked by pairs of bridging chloride anions into dinuclear units that are further linked into layers via bridging 2,3-di-methyl-pyrazine coligands. These layers are stacked in such a way that channels are formed in which the disordered solvent mol-ecules are located. The topology of this network is completely different from that observed in the two polymorphic modifications of CuCl(2,3-di-methyl-pyrazine) reported in the literature [Jess & Näther (2006). Inorg. Chem. 45, 7446-7454]. Powder X-ray diffraction measurements reveal that the title compound is unstable and transforms immediately into an unknown crystalline phase.

On the Role of Water in the Formation of a Deep Eutectic Solvent Based on NiCl2·6H2O and Urea.

The metal-based deep eutectic solvent (MDES) formed by NiCl2·6H2O and urea in 1:3.5 molar ratio has been prepared for the first time and characterized from a structural point of view. Particular accent has been put on the role of water in the MDES formation, since the eutectic could not be obtained with the anhydrous form of the metal salt. To this end, mixtures at different water/MDES molar ratios (W) have been studied with a combined approach exploiting molecular dynamics and ab initio simulations, UV–vis and near-infra-red spectroscopies, small- and wide-angle X-ray scattering, and X-ray absorption spectroscopy measurements. In the pure MDES, a close packing of Ni2+ ion clusters forming oligomeric agglomerates is present thanks to the mediation of bridging chloride anions and water molecules. Conversely, urea poorly coordinates the metal ion and is mostly found in the interstitial regions among the Ni2+ ion oligomers. This nanostructure is disrupted upon the introduction of additional water, which enlarges the Ni–Ni distances and dilutes the system up to an aqueous solution of the MDES constituents. In the NiCl2·6H2O 1:3.5 MDES, the Ni2+ ion is coordinated on average by one chloride anion and five water molecules, while water easily saturates the metal solvation sphere to provide a hexa-aquo coordination for increasing W values. This multidisciplinary study allowed us to reconstruct the structural arrangement of the MDES and its aqueous mixtures on both short- and intermediate-scale levels, clarifying the fundamental role of water in the eutectic formation and challenging the definition at the base of these complex systems.

Di-aqua-bis-{μ-1,5-bis-[(pyridin-2-yl)methyl-idene]carbonohydrazide(1-)}di-μ-chlorido-tetra-chlorido-tetra-zinc(II).

A tetra-nuclear ZnII complex, [Zn4(C13H11N6O)2Cl6(H2O)2] or {[Zn2(HL)(H2O)(Cl2)](μCl)2[Zn2(HL)(H2O)(Cl)]}2, was synthesized by mixing an equimolar amount of a methanol solution containing ZnCl2 and a methanol solution containing the ligand H2 L [1,5-bis-(pyridin-2-yl-methyl-ene)carbono-hydrazide]. In the tetra-nuclear complex, each of the two ligand mol-ecules forms a dinuclear unit that is connected to another dinuclear unit by two bridging chloride anions. In each dinuclear unit, one ZnII cation is penta-coordinated in a N2OCl2 in a distorted square-pyramidal geometry, while the other ZnII cation is hexa-coordinated in a N3OCl2 environment with a distorted octa-hedral geometry. The basal plane around the penta-coordinated ZnII cation is formed by one chloride anion, one oxygen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical position occupied by a chloride anion. The basal plane of the hexa-coordinated ZnII cation is formed by one chloride anion, one hydrazinyl nitro-gen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical positions occupied by a water oxygen atom and a bridged chloro anion from another dinuclear unit, leading to a tetra-nuclear complex. A series of intra-molecular C-H⋯Cl hydrogen bonds is observed in each tetra-nuclear unit. In the crystal, the tetra-nuclear units are connected by inter-molecular C-H⋯Cl, C-H⋯O and N-H⋯O hydrogen bonds, forming a planar two-dimensional structure in the ac plane.

Trinuclear and Hexanuclear Lanthanide(III) Complexes of the Chiral 3+3 Macrocycle: X-ray Crystal Structures and Magnetic Properties

A new triphenolic hexaaza chiral macrocyclic amine L forms trinuclear complexes 1-3 with rare earth metal lanthanide(III) ions (Ln = Dy, Eu, and Y) with the general formula [Ln3L(μ3-OH)2(NO3)4(H2O)2]· xCH3OH. The crystal structures of the nitrate derivatives of this type reveal the presence of a {Ln3(μ3-OH)2} core within the macrocycle. For the chloride derivative of dysprosium(III) 4, a duplex of the trinuclear compound is formed to give the hexanuclear [Dy6L2(μ3-OH)3(μ3-O)(μ2-Cl)3Cl4(H2O)2] compound, in which two trinuclear macrocyclic units are linked by bridging chloride anions, supplemented by a hydrogen bond connecting the central oxo and hydroxo bridges as well as by weak interactions at the periphery of the macrocycle. The nuclear magnetic resonance spectra of these complexes reveal a dynamic behavior in solution related to exchange of axial ligands and hindered rotation of phenyl substituents. Magnetic studies of the nitrate (1-3) and chloride (4) dysprosium(III) complexes suggest the presence of weak ferromagnetic interactions between neighboring metal centers. The interaction is strongest for compound 1, and for the related duplex compound 4, it appears to be somewhat weaker. The ac susceptibility measurements for complexes 1 and 4 confirm their field-induced single-molecule magnet behavior with the following characteristics: Ueff = 10.6 cm-1 (15.2 K), τ0 = 2.05 × 10-4 s under 2500 Oe dc fields for 1; Ueff = 7.9 cm-1 (11.4 K), τ0 = 1.68 × 10-4 s under a 3000 Oe dc field for 4.

Chromotropism in halo-bridged dimers. Structural characterization of bis(μ-halo)bis(halo N-(pyridin-2-ylmethyl)cyclohexanamine copper(II))

Two dinuclear copper(II) complexes, [LCu(μ-Cl)Cl]2 (DMF) (1) and [LCu(μ-Br)Br]2 (2), with the bidentate ligand N-(pyridin-2-ylmethyl)cyclohexanamine, L, were synthesized and characterized by physicochemical and spectroscopic (IR, UV–vis) data. The crystal structural analysis of 1 shows that both copper(II) ions are in a distorted square pyramidal N2Cl3 environment with the apical position of the copper(II) being occupied by the bridging chloride anion which is equatorial to the other copper ion, forming a dimeric copper(II) complex. The chromotropic properties of both complexes, including solvato-, thermo-, and halochromism, were investigated. The complexes show reversible thermochromism in solution which is irreversible in the solid state. It was found that the solvatochromism is due to structural change followed by solvation of the vacant sites of the complexes. Their halochromic properties were studied in pH range of 1–11 by visible absorption spectroscopy. The color changes from blue to green and to colorless are due to deprotonation and protonation of the ligands.

1,2-Bis(di-cyclo-hexyl-phosphan-yl)-1,2-dicarba-closo-dodeca-borane-2κ(2) P,P']di-μ-chlorido-1:2κ(4) Cl:Cl-di-chlorido-1κ(2) Cl-dimercury(II).

The title compound, [Hg2Cl4(C26H54B10P2)], was synthesized by the reaction of 1,2-bis­(di­cyclo­hexyl­phosphan­yl)-1,2-dicarba-closo-dodeca­borane with HgCl2. Both HgII atoms show a distorted tetra­hedral coordination geometry, provided by the two bridging chloride anions and the P atoms of the diphosphanyl ligand for one metal atom, and by two bridging and two terminal chloride anions for the other. The five-membered HgP2C2 chelate ring assumes an envelope conformation, with the HgII atom displaced by 0.1650 (5) Å from the mean plane of the other four atoms (r.m.s. deviation = 0.002 Å). In the crystal, B—H⋯Cl interactions link the molecules, forming a supramolecular chain along the a-axis direction.

Copper(ii) complexes with 3-(2-pyridyl)-4,5-dihydro-1H-pyrazoles: synthesis, structural and electrochemical studies

Three new copper(ii) complexes with the 3-(2-pyridyl)-4,5-dihydro-1H-pyrazole ligands were obtained by reactions of appropriate organic ligands with CuCl2·2H2O. The structures of the complexes were determined by X-ray diffraction. The molecular formula of all the complexes can be written as 2(L·MCl2) (L is an organic ligand). The coordination polyhedron of either copper ion is a distorted trigonal bipyramid made up of two N atoms (coming from the pyrazoline and pyridine rings) and one axial and two bridging chloride anions. The electrochemical behavior of 1,5-diphenyl-3-(2-pyridyl)-4,5-dihydro-1H-pyrazole and its CuII complex was studied by cyclic voltammetry; the mechanisms of their electrooxidation and electroreduction were proposed.

Two novel trimethylsulfonium salts with polymeric {[SbCl4]−}nor {[CdCl3]−}nanions

The title organic-inorganic hybrid salts poly[trimethylsulfonium [[dichloridoantimony(III)]-di-μ-chlorido]], {(C3H9S)[SbCl4]}n, (I), and catena-poly[trimethylsulfonium [cadmium(II)-tri-μ-chlorido]], {(C3H9S)[CdCl3]}n, (II), consist of trimethylsulfonium cations and polymeric {[SbCl4](-)}n or {[CdCl3](-)}n anions. The central metal atoms are coordinated by six Cl atoms, forming an anionic {[SbCl4](-)}n three-dimensional framework (two of the four bridging chloride anions are located on two different centres of inversion) or anionic {[CdCl3](-)}n one-dimensional chains. The trimethylsulfonium cation of (II) is disordered over two sets of sites in a 0.791 (4):0.209 (4) ratio. All the anions are linked by trimethylsulfonium cations through weak C-H···Cl hydrogen bonds to form three-dimensional structures.

Observation of a Chloride-Bridged P–P Bond in the Phosphorus Cation [L(Cl)P(μ-Cl)P(Cl)L]+ (L = NHC)

A bridging chloride anion between two electrophilic phosphorus centers was observed for the first time in the molecular structure of the novel P–P bonded cation [LDipp2P2Cl3]+ (2+; LDipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Cation 2+ is prepared by the reduction of the monophosphorus species [LDippPCl2]+ (1+) with sodium. DFT calculations, AIM and mechanochemical (compliance constants) analyses are used to examine the bonding situation of this unusual species. The monochloro-substituted cation [LDipp2P2Cl]+ (3+) was likewise observed as a reduction product of 1+.

Cu(II) and Ni(II) complexes with a tri-, tetra- or hexadentate triethanolamine ligand: Structural characterization and properties

One Cu(II) (1) and two Ni(II) (2,3) novel compounds based on triethanolamine have been obtained and characterized by elemental and spectral analyses. Single-crystal X-ray crystallography has revealed that the crystal structure of compound 1 results from co-crystallization of ionic dinuclear [Cu2(H3L)2Cl2]Cl2 (1a) and molecular tetranuclear [Cu4(HL)2Cl4] (1b) species in a 1:0.036 ratio, both possessing an atrane structure. The molecular structure of [Ni2(H3L)2Cl2]Cl2 (3) resembles the compound [Cu2(H3L)2Cl2]Cl2 (1a). In both centrosymmetric dinuclear complexes, each metal atom exhibits an octahedral Cl2NO3 coordination provided by a tetradentate non-deprotonated triethanolamine ligand and two bridging chloride anions. The compound [Ni(H3L)2]Cl2 (2) has an ionic crystal structure, where triethanolamine acts as a non-deprotonated tridentate ligand, one of the OH-groups not being involved in coordination to the Ni atom. Analysis of the magnetic susceptibility results for compounds 1–3 reveals the presence of an antiferromagnetic interaction in the case of the Cu-based dimer 1 (J=−1.99(7)cm−1, g=2.07(9)) and a ferromagnetic interaction for the Ni-based dimer 3 (J=+7.17(3)cm−1, g=2.35(2)) with the ground state S=2. A significant zero field splitting (ZFS) effect was found for the Ni(II)-based complexes (D=−6.5cm−1, E=0.4cm−1). The thermal stability of the compounds was studied under a nitrogen atmosphere. The biocidal activities against some fungi (Aspergillus niger ATCC 53346, Penicillium frequentans ATCC 10110, Alternaria alternate ATCC 8741) and bacteria (Pseudomonas aeroginosa ATCC 27813 and Bacillus sp. ATCC 15970) were also evaluated. The moisture behavior of the obtained crystalline compounds was studied by dynamic water vapor sorption analysis.

Bis{4-[(3,5-dimethyl-1H-pyrazol-4-yl)selan-yl]-3,5-dimethyl-1H-pyrazol-2-ium} chloride monohydrate.

In the title compound, 2C10H15N4Se+·Cl−·OH−, a singly protonated mol­ecule of the organic selenide participates in hydrogen bonding with neighboring mol­ecules, forming zigzag chains along [001]. The molecule adapts a cis bridging mode with a C—Se—C angle of 102.13 (15)°. π–π stacking inter­actions are observed between the closest pyrazole rings of neighboring chains [centroid–centroid distance = 3.888 (1) Å] and hydrogen bonding occurs through bridging chloride anions and hydroxide groups. Additionally, O—H⋯Cl hydrogen bonds are formed.

μ3-Chlorido-tris(bis{1-[2-(dimethylamino)ethyl]-3-methylimidazol-2-ylidene}silver(I)) dichloride

In the crystal structure of the title compound, [Ag3Cl(C8H15N3)6]Cl2, the AgI ion, which is located on a twofold rotation axis, exists in a T-shape coordination environment. Two carbene C atoms of the N-heterocyclic carbene (NHC) ligands are bonded tightly forming a slightly bent [Ag(NHC)2]+ cation [C—Ag—C angle = 162.80 (18)°]. Three of these complex cations are further aggregated by one bridging chloride anion, which is lying on a threefold rotoinversion axis and is only loosely binding to the Ag+ ions. The N atom of the amine group is not engaged in any coordinative bond.

Di-μ-chlorido-bis{[N,N′-dicyclohexyl-N′′,N′′-bis(trimethylsilyl)guanidinato-κ2N,N′](tetrahydrofuran-κO)magnesium(II)}

The dinuclear title complex, [Mg2(C19H40N3Si2)2Cl2(C4H8O)2], lies on a center of inversion. The Mg2+ ions are bonded to a chelating N,N′-bonded guanidinate anion, a tetra­hydro­furan mol­ecule and two bridging chloride anions. The geometry of the resulting five-coordinated Mg2+ ion is a very distorted square-based pyramid with the O atom in the apical position.

The crystal structure and spectroscopic properties of catena- (2-methylimidazolium bis(μ2-chloro)-aqua-chloromanganese(II))

? novel manganese(II) coordination polymer, catena-(2- methylimidazolium bis(?2-chloro)-aqua-chloromanganese(II)), {(C4H7N2)[MnCl3(H2O)]}n, was synthesized, structurally characterized by FTIR spectroscopy and confirmed by single crystal X-ray diffraction analysis. Thermogravimetric analysis and EPR spectroscopy of the compound were also performed. The colourless crystals of the complex were monoclinic, space group P21/c, with the cell parameters a = 11.298(2) ?, b = 7.2485(14) ?, c = 14.709(5) ?, ? = 128.861(18)?, V = 938.0(5) ?3, Z = 4 and R1 = 0.03. The title compound consisted of onedimensional infinite anionic chains [MnCl3(H2O)]n and isolated 2- methylimidazolium cations. The Mn(II) atom was octahedrally coordinated to four bridging chloride anions [Mn-Cl = 2.5109(6) - 2.5688(7) ?], one terminal chloride anion [Mn-Cl = 2.5068(11) ?] and a H2O molecule [Mn-O = 2.2351(17) ?]. A three-dimensional layer structure was constructed via hydrogen bonds and by weak ?-? stacking interactions. A four-step thermal decomposition occurred in the temperature range 25-900?C under nitrogen.

Poly[di-μ(2)-chlorido-μ(2)-(1,4-dioxane-κO:O')-cadmium(II)

In the title complex, [CdCl2(C4H8O2)]n, two different CdII ions are present, one in a general position and one with site symmetry 2. The CdII ions are coordinated by two O atoms from two 1,4-dioxane ligands and four chloride anions in a slightly distorted octa­hedral geometry and is connected to neighboring CdII ions by two bridging chloride anions, generating infinite linear chains along the a axis. These chains are further inter­connected by bridging 1,4-dioxane ligands, affording a three-dimensional network.

Ba5Cl4(H2O)8(VPO5)8: a novel three-dimensional framework solid

The novel hydrothermally synthesized title compound, pentabarium tetrachloride octahydrate octakis(oxovanadium phosphate), Ba(5)Cl(4)(H(2)O)(8)(VPO(5))(8), crystallizes in the orthorhombic space group Cmca with a unit cell containing four formula units. Two Ba(2+) cations, two Cl(-) anions and the O atoms of four water molecules are situated on the (100) mirror plane, while the third independent Ba(2+) cation is on the intersection of the (100) plane and the twofold axis parallel to a. Two phosphate P atoms are on twofold axes, while the remaining independent P atom and both V atoms are in general positions. The structure is characterized by two kinds of layers, namely anionic oxovanadium phosphate (VPO(5)), composed of corner-sharing VO(5) square pyramids and PO(4) tetrahedra, and cationic barium chloride hydrate clusters, Ba(5)Cl(4)(H(2)O)(8), composed of three Ba(2+) cations linked by bridging chloride anions. The layers are connected by Ba-O bonds to generate a three-dimensional structure.

Di-μ-chlorido-bis[chlorido(1,10-phenanthroline-κ2N,N′)zinc(II)

In the crystal structure of the title complex, [Zn2Cl4(C12H8N2)2], each of the two five-coordinated ZnII atoms displays a strongly distorted trigonal-bipyramidal geometry defined by two N atoms from the chelate ligand and by one terminal and two bridging chloride anions. The crystal structure is stabilized by C—H⋯Cl inter­actions. There is inter­molecular π–π stacking between adjacent phenanthroline ligands, with a centroid–centroid distance of 3.151 (3) Å.

Di-μ-chlorido-bis[(2,2′-bibenzimidazole)chloridocadmium(II)

The title binuclear complex, [Cd2Cl4(C14H10N4)2], was synthesized by the hydro­thermal reaction of CdCl2 and the ligand 2,2′-bibenzimidazole. The mol­ecule lies on an inversion center and the metal center displays a strongly distorted trigonal-bipyramidal geometry. The CdII ions are coordinated by two N atoms from the organic ligand, and by one terminal and two bridging chloride anions. The crystal structure involves inter­molecular N—H⋯Cl hydrogen bonds, resulting in a one-dimensional supra­molecular structure.

Di-μ-chlorido-bis{bis[3,5-dimethylpyrazol-1-yl-κN2)methane]iron(II)} bis[tetrachloridoferrate(III)

In the title complex, [Fe2Cl2(C11H16N4)4][FeCl4]2, the asymmetric unit is composed of one and a half units of [Fe(bdmpm)2Cl]2(FeCl4)2(bdmpm = bis(bis(3,5-dimethyl­pyrazol-1-yl)methane). The three independent FeII atom have a distorted octa­hedral coordination geometry comprising two bridging chloride anions and four N atoms from two bis­(3,5-dimethyl­pyrazol-1-yl)methane ligands. The FeIII atom has a tetra­hedral coordination geometry comprising four chloride anions.

Catena-Poly[1,10-phenanthroline-1,10-diium [[dichloridobismuthate(III)]-di-μ-chlorido

The asymmetric unit of the title compound, {(C12H10N2)[BiCl4]}n, comprises one 1,10-phenanthrolinium dication and one Bi atom with two terminal and two bridging chloride anions. The Bi atoms adopt a distorted octa­hedral configuration and are each bridged to two other Bi atoms by four chloride ligands to generate a one-dimensional polymer chain running along a. C—H⋯Cl hydrogen bonds link the phenanthrolinium dications to these chloro­bismuthate chains.