Synthesis and crystal structures of silver(I) and copper(II) complexes with <Emphasis Type="Italic">p</Emphasis>-xylylene-bridged bipyrazolyl ligands

Two semi-rigid bipyrazolyl ligands, namely 2,3,5,6-tetramethyl-1,4-bis[(3′,5′-dimethyl-1H -pyrazol-4′-yl)methylene]benzene (H₂L) and 2,3,5,6-tetramethyl-1,4-bis[(3′,5′-diphenyl-1H -pyrazol-4′-yl)methylene]benzene (H₂L′), and their Ag(I) and Cu(II) complexes have been prepared and structurally characterized by means of X-ray analysis. In the structures of the metal complexes, namely [Ag₂(H₂L)₂](BF₄)₂·2H₂O (1), [Ag(H₂L)(NO₃)]_n (2), [Cu₂(H₂L)₄(SO₄)₂]·11H₂O (3), and {[Ag(H₂L′)]BF₄}_n (4), the bipyrazoles act as bridging ligands to connect two metal atoms. Complexes 2 and 4 exhibit 1-D polymeric structures, while 1 and 3 are discrete molecules with a rectangular dimer or tetragonal prismatic shapes, respectively. Two different conformations, namely cis and trans, have been observed for these bipyrazolyl ligands.     

Hydrothermal synthesis and crystal structure of [Ni(Bptc)<Subscript>2</Subscript>(Bimb)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]

In the compound [Ni(Bptc)₂(Bimb)₂(H₂O)₂] (I), where H₄Bptc is 3,3′,4,4′-biphenyltetracarboxylic acid; Bimb is 4,4′-bis(1-imidazolyl)biphenyl), Ni(II) has a distorted octahedral coordination geometry, which was bonded with two N atoms from two Bimb ligands, two O atoms from two H₂Bptc²⁻ ligands and two water O atoms. The crystal structure of compound I is stabilized by the π-π-stacking and hydrogen bonds interaction.     

2,2'-联吡啶-3,3',6,6'-四羧酸过渡金属配合物的合成、结构及性质

以2,2'-联吡啶-3,3',6,6'-四羧酸(H₄bptc)为配体,通过水热合成的方法与过渡金属盐合成了3个配合物,其分子式分别为[Co₂(H₂bptc)₂(H₂O)₄]·bpe·9H₂O(1),[Ni₂(H₂bptc)₂(H₂O)₄]·bpe·9H₂O(2),[Ni₂(H₂bptc)₂(H₂O)₄]·0.5bpp·7H₂O(3)(bpe=1,2-二(4-吡啶基)乙烯,bpp=1,2-二(4-吡啶基)乙烷)。用红外光谱,X-射线单晶衍射对化合物的晶体结构进行了表征,并对这3个配合物的热稳定性进行了测试。化合物1~3为单核结构的配合物,它们均通过分子间氢键形成三维超分子结构。     

Synthesis and crystal structures of four mixed-ligand silver(I) complexes with sandwich-like structure

The reaction of AgNO₃, with combinations of 4,4′-bipyridine (bpy), 1,2-di(4-pyridyl)ethylene (dpe), hexanedioic acid (HA), pyridine-3,5-dicarboxylic acid (pdc) and 3,3′4,4′-biphenyltetracarboxylic acid (bptc) in aqueous alcohol at room temperature produces block-like crystals of [Ag₂(bpy)₂](HA)₂·6H₂O, [Ag₂(bpy)₂(H₂O)](pdc)·3H₂O, [Ag₄(bpy)₄](bptc)·14H₂O and [Ag₂(dpe)₂(H₂O)₂](HA)·6H₂O. All four compounds consist of parallel 1D infinite bpy/dpe-silver cationic chains, interspersed with organic anions that play the role of charge compensation in the crystal structure. The lattice water molecules are situated among the framework of the crystal structure and stabilized by rich hydrogen-bonding interactions, which may play a role in the orientation of the organic anions in the crystal packing.     

2,2'-联吡啶-3,3',6,6'-四羧酸过渡金属配合物的合成、结构及性质

以2,2'-联吡啶-3,3',6,6'-四羧酸(H₄bptc)为配体,通过水热合成的方法与过渡金属盐合成了3个配合物,其分子式分别为[Co₂(H₂bptc)₂(H₂O)₄]·bpe·9H₂O(1),[Ni₂(H₂bptc)₂(H₂O)₄]·bpe·9H₂O(2),[Ni₂(H₂bptc)₂(H₂O)₄]·0.5bpp·7H₂O(3)(bpe=1,2-二(4-吡啶基)乙烯,bpp=1,2-二(4-吡啶基)乙烷)。用红外光谱,X-射线单晶衍射对化合物的晶体结构进行了表征,并对这3个配合物的热稳定性进行了测试。化合物1~3为单核结构的配合物,它们均通过分子间氢键形成三维超分子结构。     

Synthesis,crystal structures,and magnetic properties of cobalt(II) and nickel(II) complexes of 2,2′-bipyridine-6,6′-dicarboxylate: three three-dimensional networks formed via hydrogen bonding interactions

Three Co(II) and Ni(II) complexes, namely [Co(bpdc)(H₂O)₂] (1), [Ni(bpdc)(H₂O)₂] (2), and [Co₂(bpdc)₂(prz)_0.5(H₂O)₃]·0.5H₂O (3) (H₂bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid and prz = piperazine), have been synthesized from H₂bpdc and the corresponding metal salts under hydrothermal conditions. The complexes were characterized by physico-chemical and spectroscopic methods, as well as by X-ray crystallography. Compounds 1 and 2 both consist of neutral mononuclear molecules, of [Co(bpdc)(H₂O)₂] and [Ni(bpdc)(H₂O)₂], respectively. Compound 3 consists of a mononuclear molecule of [Co(bpdc)(H₂O)₂] and a binuclear molecule of [Co₂(bpdc)₂prz (H₂O)₂]. The discrete neutral complexes 1–3 further extend their structures into three-dimensional supramolecular architectures by intermolecular O–H⋯O and C–H⋯O hydrogen bonds as well as π–π stacking interactions. Magnetic susceptibility measurements show that complex 3 exhibits weak ferromagnetic interactions between the two Co(II) ions bridged by the prz ligand, with C = 5.41 cm³ mol⁻¹ K and θ = +27.6 K, respectively.     

Structure and magnetic properties of the copper(II) complexes with diacyl hydrazides of salicylic acid

The structures and results of the static magnetic susceptibility investigation of the copper(II) binuclear complex with salicylic acid diacyl hydrazide (H₂L), [Cu₂(L)(Py)₄] (I), and the copper(II) trinuclear complex with diacyl dihydrazide of salicylic and glutaric acids (H₆L′), [Cu₃(L′)(Py)₄] · 2Py (II), are described. The exchange antiferromagnetic interactions between the paramagnetic centers with the exchange interaction parameter −2J = 119 cm⁻¹ for dimer I and 14 cm⁻¹ for trinuclear complex II are detected.     

Three silver(I) coordination polymers assembled from 2-sulfoterephthalic acid and N-donor ligands: syntheses, crystal structures, and luminescence properties

The reactions of silver nitrate with 2-sulfoisophthalic acid (H₃stp) in the presence of N-donor ligands produced three coordination polymers; [Ag₃(stp)(pyz)_0.5]_n (1), {[Ag₄(dpp)₄]·2(Hstp)·9H₂O}_n (2), and {[Ag(bpe)]₂[Ag₂(bpe)₂]₂·2(stp)·19H₂O}_n (3) [pyz = pyrazine, bpp = 1,2-bis(4-pyridyl)propane, bpe = 1,2-di(4-pyridyl)-ethylene]. The complexes have been characterized by single-crystal X-ray diffraction, physico-chemical, and spectroscopic methods. Single-crystal X-ray diffraction reveals that complex 1 is a 2D silver carboxylate-sulfonate layered structure, in which the 2D layers are further linked by the N-donor atoms of pyz ligands into a 3D supramolecular structure. Complex 2 is an infinite 1D chain arrangement with the [Ag₂(dpp)₂]²⁺ unit in which weak Ag···Ag or Ag···O interactions extend the chains into 2D structures. Complex 3 has a 3D supramolecular structure constructed by hydrogen bonding, π–π stacking, and Ag···O interactions to link the ligands, metal atoms, and water molecules together. The luminescence properties of the complexes were investigated.     

Preparation,characterization, and properties of a Ag(I) coordination polymer {[Ag(H3bptc)(bpe)] · 2H2O} n

A new coordination polymer, {[Ag(H₃bptc)(bpe)]?·?2H₂O} _n (1) (H₄bptc?=?3,3′,4,4′-benzophenonetetracarboxylic acid, bpe?=?1,2-bis(4-pyridyl)ethene), has been synthesized through a hydrothermal technique and structurally characterized. The crystal structure of 1 exhibits a 2-D hydrogen-bonding sheet between H₃bptc^? and two free water molecules. Fluorescent property, TG analysis, and X-ray powder diffraction for 1 were also measured and discussed.     

Ruthenium(II)-arylazoimidazole-8-hydroxyquinolinate complexes: Synthesis,spectral study (H,C, COSY,HMQC-NMR) and redox properties

The reaction of [Ru(OH₂)₂(RaaiR′)₂]²⁺ (RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C₆H₄-N=N-C₃H₂NN(1)-R′, R = H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH₂Ph (c)) with 8-quinolinol (HQ) in acetone solution followed by the addition of NH₄PF₆ has afforded violet coloured mixed ligand complexes of the composition [Ru(Q)(RaaiR′)₂](PF₆). The maximum molecular peak of 1b is observed at m’z 790 (50%) in the ESI mass spectrum. Ir spectra of the complexes show -C=N- and -N=N- stretching near at 1590 and 1370 cm⁻¹. The ¹H NMR spectral measurements suggest methylene, -CH₂−, in RaaiEt gives a complex AB type while in RaaiCH₂Ph it shows AB type quartets. Considering the arylazoimidazole and oxine moitie there are twenty different carbon atoms in the molecule which gives a total of twenty different peaks in the C¹³ NMR spectrum of complex 1a. In the ¹H-¹H COSY spectrum of the present complexes, absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirm their assignment of no proton on N(1) and N(3) respectively. Contour peaks in the ¹H-¹³C HMQC spectrum in the present complexes, the absence of any contours at δ = 157.12, 160.76, 155.67 ppm and 157.68–160.2 ppm assign them to the C(2), C(6), C(g) and C(h), C(i) carbon atoms respectively. The solution structure and stereoretentive transformation in each step have been established from n.m.r. results. Cyclic voltammograme show a Ru(III)/Ru(II) couple at 1.0–1.1 V versus SCE along with three successive ligand reductions.     

Synthesis and crystal structures of two polymeric silver(I) complexes with polyamines and terephthalic acid

Two polymeric silver(I) complexes, [Ag₄(TAA)₂(TA)₂] · 2[Ag(TA)₂] (I) and [Ag₂(TA)(BA)] _n (II), where TAA is tris(2-aminoethyl)amine, TA is terephthalic acid, BA is butane-1,4-diamine, were synthesized and structurally characterized by elemental analyses and X-ray diffraction. Complex I consists of mononuclear [Ag(TA)₂] units and TA-bridged tetranuclear [Ag₄(TAA)₂(TA)₂] units, which are further linked via Ag…Ag interactions to form chains. In complex II, the silver atoms are linked by the TA and BA groups to form chains, which are further linked via Ag…Ag interactions to form layers. In both complexes, molecules are finally linked through intermolecular hydrogen bonds to form three-dimensional networks.     

A Novel Coordination Polymer, [Ag4^1 （bpdc）（H2bpdc）（Hbpdc）2]n （bpdc = 2,2＇-bipyridyl-3,3＇-dicarboxylate）： Coordination Models of bpdc Ligands

A novel coordination polymer, [Ag₄ppdc)(H₂bpdc)(Hbpdc)₂] (bpdc = 2,2′‐bipyridyl‐3,3′‐dicarboxylate), was hydrothermally synthesized at 403 K and structurally characterized by single crystal X‐ray diffraction analysis. The compound crystalizes in the monoclinic space group C2/c with a=1.9516(4) nm, b=1.9503(4) nm. c=1.2566(3) nm, and β=112.48(3)°. In the two‐dimensional crystal structure, Ag^I center is coordinated, in a scarce coordination environment, double‐capped tetrahedron, by one bpdc ligand to form N‐Ag‐N chelate bond via two pyridyl N atoms, and other two bpdc ligands to form two O‐Ag‐O chelate bonds, respectively, via two carboxyl O atoms. The bpdc ligands are present in one non‐protonated form, bpdc, and two protonated forms, Hbpdc and H2bpdc, which all act as μ3‐ligand in a hexadentate fashion (N, N′; O, O′; O, O′) to coordinate with three Ag centers, respectively, through the three chelate bonds. This coordinated fashion of bpdc ligand is first found in the title compound. W‐Us‐NIR reflectance spectroscopy study revealed insulator nature for the crystal with an optical energy gap of 3.1 eV.     

Hydrothermal Synthesis and Characterization of a Polymeric Network Constructed by Tetranuclear [Yb<Subscript>4</Subscript>(μ<Subscript>3</Subscript>-OH)<Subscript>4</Subscript>]<Superscript>8+</Superscript> Cluster and 2,2′-bipyridine-3,3′-dicarboxylate

Abstract  

A new lanthanide coordination polymer, {[Yb₄(μ ₃ -OH)₄(bpdc)₄(H₂O)₆]}₂·17(H₂O) (1), which contains the tetranuclear lanthanide cluster of cubane-like [Yb₄(μ ₃ -OH)₄]⁸⁺, was obtained by hydrothermal reaction. As building blocks, [Yb₄(μ ₃ -OH)₄]⁸⁺ clusters were further assembled into two-dimensional network structure through the linking of 2,2′-bipyridine-3,3′-dicarboxylate (bpdc) with different four coordination modes. It is unprecedented that the adjacent [Yb₄(μ ₃ -OH)₄]⁸⁺ clusters are in the arraying form of ···AABB···(Yb1–Yb4 unit as A and Yb5–Yb8 unit as B). The thermal stability and magnetic property of compound 1 were investigated further.     

Supramolecular assembly of three Ag(I) coordination polymers derived from flexible N-containing ligands and polycarboxylates: synthesis,structures, and catalytic properties

Three Ag(I) coordination polymers [Ag(L1)]·(H₃bptc)·H₂O (1), [Ag₂(L2)(oba)]·H₂O (2), and [Ag₂(L2)₂]·(H₂bptc) (3) [L1 = 1,4-bis(3,5-dimethylpyrazole)butane, L2 = 1,4-bis(2-methylbenzimidazole)butane, H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, H₂oba = 4,4′-oxybis(benzoic acid)] constructed from N-containing ligands with different flexibilities and organic carboxylates as co-ligands have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis. All three complexes display 1D chain structures, which are further extended into 2D supramolecular networks via non-classical C–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of the complexes 1–3 have been investigated in detail. Complexes 2 and 3 reveal promising catalytic activities for the degradation of methyl orange in a Fenton-like process.     

Silver(I) 3-D-supramolecular coordination frameworks constructed by the combination of coordination bonds and supramolecular interactions

Room temperature reactions of the ternary adducts of AgNO₃, bipodal ligand [4,4′-bipyridine (4,4′-bpy) or trans-1,2-bis(4-pyridyl)ethylene (tbpe) or 1,2-bis(4-pyridyl)ethane (bpe)] and organic ligand [4-aminobenzoic acid (4-aba) or 4-hydroxybenzoic acid (4-hba) or terephthalate ion (tph)] afford new 3-D supramolecular coordination polymers (SCPs), namely, {[Ag(4,4′-bpy) · H₂O](4-ab) · 2H₂O} (1), {[Ag(tbpe)]0.5(4-hb) · 3H₂O} (2), [Ag₂(L)₂ · (tph)] (L = 4,4′-bpy, tbpe) (3,4) and {[Ag₂(bpe)₂ · (tph)] · 2H₂O} (5). The bipodal ligand coordinates to silver forming a 1-D cationic chain (A), while the organic ligand and solvent form a 1-D anionic chain (B) via hydrogen bonds. The chains construct layers which are connected via hydrogen bonds and π–π stacking forming a 3-D network structure. The presence of the carboxylate, amino and hydroxyl groups in the organic ligands significantly extend the dimensionality via hydrogen bonds. All the SCPs 1–5 exhibit strong luminescence.     

Synthesis,structure, and characterization of a silver(I) coordination polymer with μ6-bridging 2,2′-bipyridyl-3,3′-dicarboxylate

A silver(I) coordination polymer, [Ag₂(bpdc)] _n (1) (H₂bpdc = 2,2′-bipyridyl-3,3′-dicarboxylic acid), has been synthesized and characterized. Compound 1 exhibits a 2-D network containing 1-D channels. Each (bpdc)^2? is an octadentate μ₆-1igand coordinating with six Ag(I)'s in 1. This coordination of (bpdc)^2? ligand is first observed here. Neighboring networks are arranged in a [ABAB···] pattern to form 3-D supramolecular architecture by π···π stacking. Compound 1 shows intense photoluminescence at room temperature.     

Porous homo- and heterochiral cobalt(II) aspartates with high thermal stability of the metal-organic framework

Metal-organic coordination polymers with the compositions [Co₂(L-asp) ₂-(bpy)] · MeOH · H₂O (1), [Co₂(L-asp)₂(bpe)] · 0.28(bpe) · H₂O (2), and [Co₂(d-asp)(l-asp)-(bpa)] · 0.25(bpa) · 1.5H₂O (3) (H₂asp is aspartic acid, bpy is 4,4′-bipyridine, bpe is trans-bis(4- pyridyl)ethylene, and bpa is 1,2-bis(4-pyridyl)ethane) were synthesized on heating cobalt(II) as-partate and N-donor ligands (bpy, bpe, or bpa) in an aqueous-methanol mixture. The structures of compounds 1⁗ash;3 were established by X-ray diffraction analysis and confirmed by X-ray powder crystallography, IR spectroscopy, thermogravimetry, and elemental analysis. The stability of the synthesized coordination polymers was studied. It was shown that they retain the framework structure on heating to 300 °C.     

Synthesis,structures and electrochemical properties of four organic–inorganic hybrid polyoxometalates constructed from polyoxotungstate clusters and transition metal complexes

Four novel organic–inorganic hybrid compounds [Cu₅ ^I(4,4′-bpy)₃(2,2′-bpy)₄][BW₁₂O₄₀] · H₂O (1), [Ni_0.5(2,2′-bpy)_1.25][Ni(2,2′-bpy)₃][Ni(2,2′-bpy)₂(H₂O)(SiW₁₁^VIW^VO₄₀)] · 0.5H₂O (2), [H₂bpy]₂[Zn(2,2′-bpy)₃]₂[Si₂W₁₈O₆₂] · 1.5H₂O (3) and [Cu^II(2,2′-bpy)₂]₂[SiW₁₂O₄₀] · 2H₂O (4) (2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, electrochemical measurements and single-crystal X-ray diffraction. Compound (1) is a novel [BW₁₂O₄₀]⁵⁻ polyoxoanion bisupported by copper(I) coordination cations with mixed 2,2′-bpy and 4,4′-bpy ligands. Compound (2) is constructed from the [SiW₁₁^VIW^VO₄₀]⁵⁻ polyoxoanions supported by [Ni(2,2′–bpy)₂]²⁺. Compound (3) is composed of a novel [Si₂W₁₈O₆₂]⁸⁻ cluster and [Zn(2,2′–bpy)₃]²⁺ complexes, which held together into a three-dimensional (3D) supramolecular network through hydrogen-bonding interactions. Compound (4) shows a 2D layer framework constructed from a bisupporting Keggin polyoxoanion cluster and [Cu(2,2′–bpy)₂]²⁺ coordination polymer fragments, resulting in 3D networks via supramolecular interactions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Low-dimensional Compounds Containing Cyano Groups. XIII. Structural–spectral Correlation of Copper Dicyanoargentates

The new mixed-valence mixed-metal complex Cu(py)₆Cu₂Ag₂(CN)₆ (py = pyridine) possesses a three dimensional polymeric crystal structure. The Cu(I) atom is tetrahedrally coordinated by two nitrogen atoms of pyridine molecules, by one nitrogen atom of the dicyanoargentate anion and by one carbon atom of the cyano group. Both the dicyanoargentate anion and the cyano group bridge the Cu(I) atom with neighboring Cu(II) atoms. These are hexacoordinated in the form of an elongated tetragonal bipyramid. The equatorial plane is formed by two nitrogen atoms from two pyridine molecules and two nitrogen atoms from bridging cyano groups. Axial positions are occupied by nitrogen atoms of the bridging [Ag(CN₂]⁻ anions. Correlation between structures of the title compound and seven other dicyanoargentates with their i.r. spectra has been studied. The coordination mode of [Ag(CN₂]⁻ anions in compounds Cu_8-xAg_x(tn)₃(CN)₁₀ x = 0.25, Cu(3-Mepy)₂Ag₂(CN)₄, Cu(py)₂Ag₂(CN)₄ and Cu(py)₄Ag₂(CN)₄ (tn is 1,3-diaminopropane, 3-Mepy is 3-methylpyridine) is predicted based on this correlation.     

Copper(I) and Silver(I) Complexes of 1-alkyl-2-(methyl)-4-(arylazo)imidazole. Synthesis, Spectral Studies and Electrochemistry

2-(Methyl)-4-(arylazo)imidazole (RLH) (1, 2) are new series of azoimidazoles. Upon treatment of alkylhalide in dry THF in presence of NaH has synthesised 1-alkyl-2-(methyl)-4-(arylazo)imidazole (RLR′) (3, 4). They belong to the azoimine family of N,N′-chelating ligand. They stabilize the Cu(I) oxidation state and we have synthesized [Cu(RLR′)₂](ClO₄) (5, 6). These complexes show a moderately intense visible band (500–600 nm) which has been assigned to 3d(Cu) → π*(ligand) transition. Ag(I) complexes of RLR′ (7, 8) are also very stable under ambient conditions and show weak transitions in the visible region. The Cu(I)-complexes show high potential Cu(II)/Cu(I) redox couple > 0.4 V vs Ag, AgCl/Cl⁻ reference electrode. All these complexes have been structurally characterized by ¹H NMR spectroscopic data.