Tetrameric zirconium(IV) compounds derived from oxozirconium(IV) chloride and heterocyclic aldimines and ketimines

Summary Interaction of ZrOCl₂:8H₂O, [Zr₄(OH)₈(H₂O)₁₆]Cl₈ 12H₂O, with the heterocyclic, aldimines (PyAlA) and heterocyclic ketimines (AcPyA) in Me₂CO in the presence of HC(OEt)₃ yields white amorphous compounds of the type [Zr₄(OH)₁₂(H₂O)₈(PyAlA)₂]Cl₄ and [Zr₄(OH)₁₂(H₂O)₁₀(AcPyA)]Cl₄. Presumably these compounds have a tetrameric dodecahedral structure, derived from the parent. The analytical data, i.r., electrical conductance and t.g. measurements all favour the tetrameric formulation. The t.g. studies also indicate the intermediacy of complex species, which lose water and the Schiff base ligands, with increase in temperature.     

Compounds of imidazoles with ruthenium(III) chloride

Summary Reaction of ruthenium(III) chloride with imidazole(Im) and different substituted imidazoles,viz. N-methylimidazole (N-MeIm), 2-methylimidazole(2-MeIm), 4-methylimidazole (4-MeIm),N-vinylimidazole(N-VIm), 2-methyl- 1-vinyl-imidazole(2-Me-1-VIm), 1,2-dimethylimidazole(1,2-Me,Im), 2-ethylimidazole(2-EtIm) and 2-ethyl-4(5)-methylimidazole (2-Et-4(5)-MeIm] yield products of the types [Ru₂L₄Cl₆] · 2 H₂O (L = N-VIm or 4-MeIm), [Ru₂L₄Cl₆] · 4 H₂O (L = Im or 2-Et-4(5)-MeIm), [Ru₂L ³ (H₂O)Cl₆] (L =N-MeIm or 2-MeIm), [Ru₂L ² (H₂O)₂Cl₆] (L = 1,2-Me₂Im or 4-MeIm), [Ru(2-Me-1-VIm)₃Cl₃] · H₂O and [Ru(2-EtIm)₃(H₂O)Cl₂]. These compounds were characterised by elemental analyses, conductometric measurements, i.r. and electronic spectral analyses. Magnetic moments range from 1.01 to 1.9 B.M. The e.s.r. spectra and g values of some of the compounds are indicative of high distortion.     

A series of new oxo-vanadium(IV) complexes with octahedral coordinated vanadium centers

A series of new oxo-vanadium(IV) complexes, [VOCl0.69(OH)0.31 (2,2′-bipy)2]Cl·2H2O (1, 2,2′-bipy?=?2,2′-bipyridine) [(VO)₂Cl₄(4,4'-bipy)₃ (H₂O)₂] (2, 4,4'-bipy?=?4,4'-bipyridine), [VO(ida)(H₂O)]_n (3, H₂ida?=?iminodiacetic acid), and [(VO)₂(oa)₄]_n·4n(H₃O)·n(H₂O) (4, H₂oa?=?oxalic acid), have been synthesized and structurally characterized. 1 contains a [VOCl_0.69(OH)_0.31(2,2′-bipy)₂]⁺ cation, Cl ^– anion and two free H₂O molecules. 2 exhibits a binuclear centrosymmetric moiety built up from two [VOCl₂(4,4'-bipy)(H₂O)] units and one bridging 4,4'-bipy ligand, which provides a rare example of a 4,4'-bipy molecule acting as monodentate ligand. 3 displays a neutral chain [VO(ida)(H₂O)]_n constructed by the linkages of [VO(H₂O)]²⁺ units and ida^2? bridging ligands, while 4 offers the only example of three kinds of oa^2- ligands coexisting within the same anionic chain [(VO)₂(oa)₄^4-]_n. Their spectroscopic properties were investigated, and the magnetic susceptibility of 4 shows antiferromagnetic behavior.     

Trennung und Charakterisierung von Chloro-aquo-hydroxo-oxo-osmaten(IV)

Separation and Characterization of Chloro-aquo-hydroxo-oxo-osmates(IV) As a result of the acidic hydrolysis of hexachloroosmate(IV), OsCl₆^2?, and/or the careful reduction of osmium tetroxide with iron(II) sulfate in hydrochloric acid products have been obtained which have been separated by column chromatography using diethylaminoethyl cellulose. On the basis of the analytically determined Os:Cl ratios, the ionic charges that could be deduced from the elution behaviour, and the absorption spectra the products have been characterized as the monomers OsCl₅(H₂O)^?, cis-OsCl₄(OH)(H₂O)^?, fac-OsCl₃(OH)₂(H₂O)^? and mer-OsCl₃(OH)(H₂O)₂, the O-bridged dimers Cl₅Os? O? OsCl₅^4?, cis-(H₂O)Cl₄Os? O? OsCl₄(H₂O)^2?and fac-(H₂O)(OH)Cl₃Os? O? OsCl₃(OH)(H₂O)^2? and the hydrogen bridges forming OH-bridged dimers shown in “Inhaltsübersicht”.     

Supramolecular approach to crystallization of polynuclear chromium(III) aqua hydroxo complexes: synthesis and crystal structures of complexes [Cr2(OH)2(H2O)8]4+ and [Cr4(OH)6(H2O)12]6+ with cucurbit[n]uril (n = 7, 8)

Supramolecular compounds of the compositions {[Cr₂(OH)₂(H₂O)₈](C₄₂H₄₂N₂₈O₁₄)₂}-(NO₃)₄·18.75H₂O (1) and {[Cr₄(OH)₆(H₂O)₁₂](C₄₈H₄₈N₃₂O₁₆)₃(NO₃)₆·55H₂O (2) were synthesized from aqueous solutions of chromium(III) nitrate and the macrocyclic cavitand cucurbit[n]uril (C_6n H_6n N_4n O_2n , where n = 7 or 8, respectively). According to the X-ray diffraction study, the polynuclear chromium aqua complexes are disposed in cavities formed by the cucurbit[n]uril molecules and are linked to these molecules through hydrogen bonds between the hydroxo and aqua ligands of the polycations and the portal oxygen atoms of the macrocycles. Compound 1 is the first example of supramolecular compounds of cucurbit[7]uril with metal aqua complexes. The isolation of the supramolecular adduct with cucurbit[8]uril 2 in the single-crystalline state allows the determination of the structure of the tetranuclear chromium aqua complex having an adamantane-like structure, [Cr₄(μ₂-OH)₆(H₂O)₁₂]⁶⁺, which has been previously unknown in the solid state.     

Structural features of copper(II) and lanthanide(III) tartratogermanate(IV) complexes

Four heterometallic tartratogermanate complexes, namely [Cu₂Ge₂(Tart)₃(H₂O)₁₀] _n · 3nH₂O and (H₃O)[LnGe₂(Tart)₃(H₂O)₆] · nH₂O (Ln³⁺ = Gd, n = 3.5; Tm, n = 3; Yb, n = 3), have been prepared via the reaction between germanium tetrachloride and D-tartaric acid (H₄Tart) in aqueous acetic acid. All complexes contain {Ge₂(Tart)₃} _n ^4n- polymer chains. The Cu²⁺ and Ln³⁺ atoms coordinate only Tart carbonyl oxygen atoms.     

Synthesis and electrochemical study of 3- and 4-(2-pyridyl)-1,3-benzothiazole complexes with transition metals (CoII, NiII, and CuII). Molecular structure of bis{(4-(2-pyridyl)-1,3-benzothiazole)copper(ii)} tetraacetate

A series of the M(L)Cl₂ · nH₂O and {M(L)}₂(OAc)₄ complexes (M = Ni^II, Co^II, and Cu^II; L is 3- and 4-(2-pyridyl)-1,3-benzothiazole) were synthesized by the reaction of L with MX₂ · nH₂O (X = Cl, OAc) in ethanol. The molecular and crystal structures of the CuL₂(OAc)₄ binuclear complex (L is 4-(2-pyridyl)benzothiazole) were determined by X-ray diffraction analysis. The copper atoms have a distorted tetragonal bipyramidal environment and are coordinated to the nitrogen atom of the pyridine moiety of the ligand and to two oxygen atoms of the bridging acetate ligands. The Cu-Cu distance is 2.6129(9) Å. The electrochemical behavior of the synthesized ligands and complexes was studied using the cyclic voltammetry and rotating disk electrode techniques in DMF solutions (0.1 M Bu₄NClO₄). The primary reduction of all the complexes under study is directed to the metal.     

Synthesis,spectroscopic and structural characterisation of vanadium(IV) and oxovanadium(IV) complexes with arsenic donor ligands

The reaction of o-C₆H₄(AsMe₂)₂ with VCl₄ in anhydrous CCl₄ produces orange eight-coordinate [VCl₄{o-C₆H₄(AsMe₂)₂}₂], whilst in CH₂Cl₂ the product is the brown, six-coordinate [VCl₄{o-C₆H₄(AsMe₂)₂}]. In dilute CH₂Cl₂ solution slow decomposition occurs to form the V^III complex [V₂Cl₆{o-C₆H₄(AsMe₂)₂}₂]. Six-coordination is also found in [VCl₄{MeC(CH₂AsMe₂)₃}] and [VCl₄{Et₃As)₂]. Hydrolysis of these complexes occurs readily to form vanadyl (VO²⁺) species, pure samples of which are obtained by reaction of [VOCl₂(thf)₂(H₂O)] with the arsines to form green [VOCl₂{o-C₆H₄(AsMe₂)₂}], [VOCl₂{MeC(CH₂AsMe₂)₃}(H₂O)] and [VOCl₂(Et₃As)₂]. Green [VOCl₂(o-C₆H₄(PMe₂)₂}] is formed from [VOCl₂(thf)₂(H₂O)] and the ligand. The [VOCl₂{o-C₆H₄(PMe₂)₂}] decomposes in thf solution open to air to form the diphosphine dioxide complex [VO{o-C₆H₄(P(O)Me₂)₂}₂(H₂O)]Cl₂, but in contrast, the products formed from similar treatment of [VCl₄{o-C₆H₄(AsMe₂)₂}_x] or [VOCl₂{o-C₆H₄(AsMe₂)₂}] contain the novel arsenic(V) cation [o-C₆H₄(AsMe₂Cl)(μ-O)(AsMe₂)]⁺. X-ray crystal structures are reported for [V₂Cl₆{o-C₆H₄(AsMe₂)₂}₂], [VO(H₂O){o-C₆H₄(P(O)Me₂)₂}₂]Cl₂, [o-C₆H₄(AsMe₂Cl)(μ-O)(AsMe₂)]Cl·[VO(H₂O)₃Cl₂] and powder neutron diffraction data for [VCl₄{o-C₆H₄(AsMe₂)₂}₂].     

Structure and luminescent properties of the cadmium(II) chloride complex with bis(benzotriazole-1-YL)methane

A procedure to synthesize a cadmium(II) chloride complex with bis(benzotriazole-1-yl)methane (L) of the composition [Cd₂L(H₂O)(C₂H₅OH)Cl₄] _n · 1.5nH₂O is developed. The compound was studied by single crystal and powder X-ray diffraction. According to the single crystal X-ray data, the complex has a ribbon-polymer structure determined by bidentate bridging type coordination of L to cadmium(II) atoms by N(3) and N(3s’) atoms. Tetramers of cadmium(II) atoms bonded by four bridging fu₂- and two fu₃-coordinated Cl atoms can be distinguished in the structure. The coordination polyhedron of cadmium(II) atoms is a distorted octahedron. The luminescent properties of L and dehydrated initial complex of the composition [Cd₂L(H₂O)(C₂H₅OH)Cl₄] _n are analyzed. It is shown that L has photoluminescence withλ_max = 477 nm in the blue spectral region, and the complex has photoluminescence in the yellow-orange range with λ_max = 577 nm at 300 K and λ_exc = 365 nm.     

Thermal studies of some biologically active oxovanadium(IV) complexes containing 8-hydroxyquinolinate and hydroxamate ligands

The thermal decomposition behaviours of oxovanadium(IV)hydroxamate complexes of composition [VO(Q)_2?n(HL^1,2)_n]: [VO(C₉H₆ON)(C₆H₄(OH)(CO)NHO)] (I), [VO(C₆H₄(OH)(CO)NHO)₂] (II), [VO(C₉H₆ON)(C₆H₄(OH)(5-Cl)(CO)NHO)] (III), and [VO(C₆H₄(OH)(5-Cl)(CO)NHO)₂] (IV) (where Q?=?C₉H₆NO^? 8-hydroxyquinolinate ion; HL¹?=?[C₆H₄(OH)CONHO]^? salicylhydroxamate ion; HL²?=?[C₆H₃(OH)(5-Cl)CONHO]^? 5-chlorosalicylhydroxamate ion; n?=?1 and 2), which are synthesised by the reactions of [VO(Q)₂] with predetermined molar ratios of potassium salicylhydroxamate and potassium 5-chlorosalicylhydroxamate in THF?+?MeOH solvent medium, have been studied by TG and DTA techniques. Thermograms indicate that complexes (I) and (III) undergo single-step decomposition, while complexes (II) and (IV) decompose in two steps to yield VO(HL^1,2) as the likely intermediate and VO₂ as the ultimate product of decomposition. The formation of VO₂ has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stabilities for the complexes has been inferred as III?>?I > II?>?IV.     

Synthesis,structures and biological properties of nickel(II) phthalates with imidazole and its derivatives

Four new nickel(II) phthalate compounds: mononuclear complexes [Ni(Im)]₆(Pht)·H₂O (1), [Ni(Pht)(Im)₃(H₂O)₂]·H₂O (2) and [Ni(Pht)(2-MeIm)₃(H₂O)₃]·H₂O (3), and coordination polymer [Ni(Pht)(4-MeIm)₂(H₂O)]_n (4) (where Pht = dianion of o-phthalic acid, Im = imidazole, 2-MeIm = 2-methylimidazole, 4-MeIm = 4-methylimidazole) have been synthesized. The complexes 1–4 were characterised by elemental analysis, IR data, thermogravimetric, and X-ray diffraction analyses. X-ray analysis shows that the asymmetric unit of 1 consists of [Ni(Im)]₆²⁺ cation, Pht²⁻ anion and solvate H₂O molecule. The phthalate dianion does not take part in coordination to metal ion. The cations, anions and water molecules are linked via   N–H?$?$O and O–H?$?$O interactions forming 2D hydrogen-bonded networks. The structures of 2 and 3 are similar to other mononuclear Ni(II) phthalate complexes where Pht²⁻ anions act as monodentate ligands and uncoordinated carboxylate oxygen atoms participate in the formation of hydrogen bonded double-chains. The structure of 4 consists of [Ni(4-MeIm)₂(H₂O)] building units connected by phthalate ions to form helical chains. The complexes 1–4 were tested for their ability to increase the biosynthesis of enzymes.     

Gas-phase solvation of Cl− with H2O,CH3OH,C2H5OH,i-C3H7OH,n-C3H7OH,and t-C4H9OH

The gas-phase clustering reactions Cl⁻ (ROH)n−1 + ROH ⇄ Cl⁻ (ROH)_n with n ⩽ 11 for ROH = H₂O, CH₃OH, C₂H₅OH, i-C₃H₇OH, n-C₃H₇OH, and t-C₄H₉OH were measured using a high-pressure mass spectrometer. It seems likely that for CH₃OH and C₂H₅OH, six ligands complete the shell structure and that ligands with n ⩾ 7 belong to the outer shell. The bond energies D(ROH---Cl⁻) increase in the order H₂O < CH₃OH < C₂H₅OH < i-C₃H₇OH < t-C₄H₉OH < n-C₃H₇OH. The observed strong bond of n-C₃H₇OH---Cl⁻ may be due to the fact that both the acidic hydrogen atoms in the −OH and terminal −CH₃ of n-C₃H₇OH interact with Cl⁻ with the most favorable configuration. For Cl⁻ switching reactions, Cl⁻ (H₂O)_n + (ROH)_n ⇄ Cl⁻ (ROH)_n + (H₂O)_n, the ΔG⁰_n values converge to the values of free energies of transfer of Cl⁻ from water to ROH solvent ( = ΔG⁰_n with n → ∞) with n ≈ 7. The observed convergence of ΔG⁰_n is due to compensation of changes in enthalpy and entropy, i.e. both ΔH⁰_n and TΔS⁰_n show increasing divergence from the values of enthalpies and entropies of transfer of Cl⁻ from water to ROH solvent, respectively, with n = 1 → 7. This is due to the stronger interactions of ROH with Cl⁻ than that of H₂O in the inner shell of Cl⁻ (ROH)_n at the expense of the less favorable entropy changes (less freedom of motion for ligands in the inner shell).     

The bimolecular structure of aquahexa‐μ‐chlorido‐μ4‐oxido‐tris(tetrahydrofuran‐κO)tetracopper(II)–hexa‐μ‐chlorido‐μ4‐oxido‐tetrakis(tetrahydrofuran‐κO)tetracopper(II)–tetrahydrofuran (2/1/4)

The title bimolecular structure, [Cu₄Cl₆O(C₄H₈O)₃(H₂O)]₂[Cu₄Cl₆O(C₄H₈O)₄]·4C₄H₈O, at 100 K has monoclinic (P2₁/c) symmetry. The structure contains nine symmetry‐independent molecules expressed in simplest molecular form as 6[Cu₄Cl₆O(C₄H₈O)₃(H₂O)·2(C₄H₈O)]:3Cu₄Cl₆O(C₄H₈O)₄. The compound exhibits a supercell (smaller than the unit cell based on weak reflections) structure due to pseudotranslational symmetry. The structure displays O—H...O hydrogen bonding between bound water ligands and tetrahydrofuran (THF) solvent molecules. The structure exhibits disorder for 12 of the THF molecules, of which seven are ligated to Cu and five are hydrogen bonded to H₂O ligands.     

Cooperative Cluster Metalation and Ligand Migration in Zirconium Metal–Organic Frameworks

Cooperative cluster metalation and ligand migration were performed on a Zr‐MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr₆M₄ (M=Ni, Co) clusters. The M²⁺ reacts with the μ₃‐OH and terminal H₂O ligands on an 8‐connected [Zr₆O₄(OH)₈(H₂O)₄] cluster to form a bimetallic [Zr₆M₄O₈(OH)₈(H₂O)₈] cluster. Along with the metalation of Zr₆ cluster, ligand migration is observed in which a Zr–carboxylate bond dissociates to form a M–carboxylate bond. Single‐crystal to single‐crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single‐crystal X‐ray structures. In³⁺ was metalated into the same Zr‐MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr‐MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs.     

Deca(hydroxo)-23-aqua-hexa(lanthanum(III)) iodide octahydrate and deca(hydroxo)-23-aqua-hexa(neodymium(III)) iodide octahydrate: Syntheses and structures

New hexanuclear complexes of lanthanum and neodymium iodides, [La₆(H₂O)₂₃(OH)₁₀]I₈ · 8H₂O (I) and [Nd₆(H₂O)₂₃(OH)₁₀]I₈ · 8H₂O (II), are synthesized and studied by X-ray diffraction analysis. The isostructural crystals of complexes I and II are orthorhombic: a = 13.197(4) Å, b = 15.152(3) Å, c = 15.302(4) Å and a = 13.060(4) Å, b = 14.967(5) Å, c = 15.098(4) Å, respectively; Z = 2, space group Pnnm. The lanthanum (neodymium) atoms coordinate the aqua and hydroxo ligands and enter the composition of the Ln₆ -containing complex cations. The coordination polyhedron (ignoring the central oxygen atom) of each atom of the complexing agent is somewhat distorted square antiprism with the aqua and hydroxo ligands being in the vertices. Four bridging ligands link this atom of the complexing agent with the four adjacent atoms.     

Novel platinum(II) and (IV) complexes of naphthaldimine schiff bases

Naphthaldimines containing N₂O₂ donor centers react with platinum(II) and (IV) chlorides to give two types of complexes depending on the valence of the platinum ion. For [Pt(II)], the ligand is neutral, [(H₂L¹)PtCl₂]·3H₂O (1) and [(H₂L³)₂Pt₂Cl₄]·5H₂O (3), or monobasic [(HL²)₂Pt₂Cl₂]·2H₂O (2) and [(HL⁴)₂Pt]·2H₂O (4). These complexes are all diamagnetic having square-planar geometry. For [Pt(IV)], the ligand is dibasic, [(L¹)Pt₂Cl₄(OH)₂]·2H₂O (5), [(L²)Pt₃Cl₁₀]·3H₂O (6), [(L³)Pt₂Cl₄(OH)₂]·C₂H₅OH (7) and [(L⁴)Pt₂Cl₆]·H₂O (8). The Pt(IV) complexes are diamagnetic and exhibit octahedral configuration around the platinum ion. The complexes were characterized by elemental analysis, UV-Vis and IR spectra, electrical conductivity and thermal analyses (DTA and TGA). The molar conductances in DMF solutions indicate that the complexes are non-ionic. The complexes were tested for their catalytic activities towards cathodic reduction of oxygen.     

Substituted imidazole complexes of platinum(IV) halides

Platinum(IV) halides formed complexes of the type PtL₂X₄ [L=1-vinyl imidazole (1,-VIm), 1-methylimidazole (1-MeIm), 1,2-dimethylimidazole (1,2-Me₂Im), 1-vinyl-2-methylimidazole (1-V-2-MeIm), 2-methylimidazole (2-MeIm), 2-ethylimidazole (2-EtIm), 2-isopropylimidazole (2-i-PrIm), and 4-methylimidazole (4-MeIm); X=Cl, Br] in neutral aqueous solution. The 1-n-butylimidazole (1-n-BuIm) ligand yielded only (LH)₂PtX₆ compound in the same medium. The compounds were characterised by elemental analyses, IR, UV-VIS and ¹HNMR spectra.     

Synthesis of unusual mixed ligand tellurium(IV) dithiocarbamates with perchlorate. Crystal and molecular structure of perchloratotris(diethyldithiocarbamato)tellurium(IV)

Synthetic and structural aspects of perchlorato complexes of tellurium(IV) with different dithiocarbamates (dtc) [(R₁R₂NCS₂) where R₁ = R₂ = methyl, ethyl, n-propyl, i-propyl; R₁R₂ = (CH₂)₅(piperidine), C₂H₄OC₂H₄ (morpholine)] are reported. The crystal structure of TeL₃ClO₄ (where L = diethyl dtc) has been determined. The crystals of the complex are monoclinic, space group P2₁/n, a = 11.379(3), b = 17.745(7), c = 14.016(8) Å, γ = 103.30(2)°, V = 2754.2 ų, F(000) = 1352, D_X = 1.61 mg M−3. The final R and R_w values are 0.047 and 0.058, respectively for 5224 unique reflections. Tellurium displays a distorted dodecahedral stereochemistry formed by two interposing trapezoids, one resulting from the four sulphurs of two L groups and the other from the two sulphurs of the third L and the two oxygens of the perchlorate ion. The average TeS distance 2.648(2) Å is close to that reported in other tris(dithiocarbamato)tellurium(IV) complexes. The perchlorate is weakly coordinated to tellurium(IV), with the average TeO distance being 2.994(8) Å. The unusual coordination of perchlorate (as a bidentate ligand) to tellurium(IV) dithiocarbamate is reported for the first time.     

Preparation,Structure, Spectral,and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ‐2‐chloronicotinato‐O,O′)‐diaquadicopper(II)

The characterization of the complexes [Cu₂(2‐Clnic)₄(H₂O)₂] ( 1 ), [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ) (where 2‐Clnic = 2‐chloronicotinate, 2,6‐Cl₂nic = 2,6‐dichloronicotinate or 5‐Brnic = 5‐bromonicotinate) was based on elemental analysis, IR, electronic and EPR spectra, and magnetic susceptibility. Complex 1 was also studied by X‐ray analysis at 298 1a and 80 K 1b . The complex 1 contains a dinuclear Cu‐acetate molecular structure in which the carboxyl groups of the 2‐chloronicotinate ligands act as bridges and water molecules are at apical positions. The stereochemistry about Cu atom at both temperatures is typical for square pyramidal geometry with CuO₄O chromophore. The Cu‐Cu distance is 2.6513(8) and 2.6382(6) Å for 1a and 1b , respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) Å, respectively, from the plane containing four oxygen atoms bonded to the Cu atom toward the apical water molecules. Strong and weak hydrogen bonds as well as C–Cl···π interactions in the crystal structure are discussed as well. Both complexes, monomeric [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and polymeric [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ), possess octahedral copper(II) stereochemistry with differing tetragonal distortions.     

New Mixed Ligand Copper(II) Complexes: Syntheses and Crystal Structures of Cu(Imid)2(H2O)L with Imid = Imidazole,L = Succinic and Fumaric Anions

Reactions of freshly prepared Cu(OH)_2—2x(CO₃)_x · yH₂O and imidazole (Imid) with succinic acid and fumaric acid, respectively, in CH₃OH/H₂O yields Cu(Imid)₂(H₂O)L with L = (C₄H₄O₄)^2— ( 1 ) and (C₄H₂O₄)^2— ( 2 ). Both isostructural complexes consist of 1D [Cu(Imid)₂(H₂O)L_2/2] polymeric chains, in which the T‐shaped [Cu(Imid)₂(H₂O)]²⁺ moieties are bridged by bis‐monodentate dicarboxylato ligands. Through the interchain hydrogen bonds between the coordinating H₂O molecule and the non‐coordinating carboxylate O atom, the polymeric chains are assembled into 2D layers, which are further assembled via interlayer N—H···O hydrogen bonds between imidazole N atom and the coordinating carboxylato O atom. Thermal analyses of 1 under N₂ stream showed that dehydration is immediately followed by decomposition of the anhydrous “Cu(Imid)₂(C₄H₄O₄)” intermediate into imidazole and “Cu(C₄H₄O₄)”. Upon further heating, sublimation of imidazole is followed by dissociation of the resulting “Cu(C₄H₄O₄)” into CO, CO₂, C₂H₄ in gaseous phase and solid CuO as residue. Crystal data: ( 1 ) C2/c (no. 15), a = 13.712(2), b = 5.589(1), c = 17.517(2)Å, β = 105.76(1)°, U = 1292.0(3)ų, Z = 4; ( 2 ) C2/c (no. 15), a = 13.758(2), b = 5.501(1), c = 17.464(2)Å, β = 106.05(2)°, U = 1270.2(3)ų, Z = 4.