Three three-dimensional supramolecular networks formed by one-dimensional chains of Ag(I) and N,N′-di(3-pyridyl)succinamide via weak intermolecular interactions

Reactions of N,N′-di(3-pyridyl)succinamide (L) with AgOTf, AgTFA and AgNO₃ (OTf = triflate, TFA = trifluoroacetate) produced three coordination polymers {Ag(L)(OTf)·DMF·MeCN}_n (1·DMF·MeCN), {Ag(L)(TFA)·2H₂O}_n (2·2H₂O) and {[Ag(L)]₂(NO₃)₂}_n (3), respectively. In 1, two one-dimensional (1D) [Ag(L)] chains are joined by the Ag⋯Ag, π⋯π and hydrogen-bonding interactions to form a 1D double chain, which is further linked to other equivalent ones via the hydrogen bonding interactions to yield a three-dimensional (3D) structure. In 2, the 1D [Ag(L)] helical chains are connected by the Ag⋯O, π⋯π, CH⋯π and hydrogen-bonding interactions to afford a 3D framework. In 3, two kinds of 1D [Ag(L)] chains are linked by the Ag⋯O and hydrogen-bonding interactions to form a 3D structure. The luminescent properties of 1–3 along with L were also investigated.     

Three new d10 coordination polymers based on 2-(2-pyridyl)benzimidazole ligand: Synthesis,structures and properties

Three coordination polymers containing 2-(2-pyridyl)benzimidazole (PyHBIm) ligand, namely {[Zn₃(PyBIm)₃(PyHBIm)₂(tma)(H₂O)]?H₂O}_n (1), [Zn(PyHBIm)(oba)]_n (2), [Cd(PyHBIm)(oba)]_n (3), (tma = trimesate, oba = 4,4′-oxybis-(benzoate)), have been prepared through hydrothermal reaction. Compound 1 exhibits one-dimensional (1D) helical structure. However, compounds 2 and 3 display 1D meso-helical structure. These 1D structures are further assembled into three-dimensional (3D) networks through aromatic π–π stacking interactions and hydrogen bonding interactions. Moreover they all exhibit strong photoluminescence at room temperature and may be good candidates for potential luminescence materials.     

A unique supramolecular sandwich structure of a tetrabromocatechol-chelated iron(III) complex: Mutual reinforcement of H-bonding and π⋯π stacking interactions in the crystal lattice

A unique supramolecular sandwich structure of a tetrabromocatecholate chelated mononuclear iron(III) complex, [H₃ntb]₂[Fe(Br₄Cat)₃](ClO₄)₃·4CH₃OH·4H₂O (1) [ntb = tris(2-benzimidazolylmethyl)amine and Br₄CatH₂ = tetrabromocatechol], is reported. The most interesting feature of the crystal structure of 1 is that the central [Fe(Br₄Cat)₃]^3 − anion is sandwiched by the triply-protonated two ntb ligands in which mutual reinforcement of the π⋯π stacking and hydrogen bonding interactions play significant role to stabilize the structural motif. Electrochemical studies disclose both the noninnocent ligand and metal based redox processes.     

A 3D Cu(II) coordination polymer constructed from BIBP (BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene) ligand with semiconductive property

Hydrothermal reaction of Cu(NO₃)₂·3H₂O with BIBP and H₂hfipbb at 105 °C yielded a novel 3D Cu(II) coordination polymer, {[Cu₂(BIBP)_0.5(hfipbb)₂(CH₃CN)]·5H₂O}_n (1) [BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene, H₂hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)]. Compound 1 displays a 3D 2-fold interpenetrating framework with {4⁴.6⁶} sqp topology, containing interesting ⋯LRLR⋯ double helical chains. The compound 1 was characterized by IR spectra, elemental analysis, thermal analysis and single crystal X-ray diffraction. In addition, solid-state UV–vis spectra experiment shows that compound 1 exhibits semiconductive property with a band gap of 2.46 eV.     

Luminescent mononuclear Pt(II) chloride complexes with C-linked 2,2′-bipyridyl tetrazole terdentate chelating ligands

Two new luminescent mononuclear Pt(II) chloride complexes possessing C-linked 2,2′-bipyridyl tetrazole terdentate chelating ligands, namely, Pt(tbpy)Cl (1) and Pt(tmbpy)Cl (2) (tbpyH = 6-(1H-tetrazol-5-yl)-2,2′-bipyridine; tmbpyH = 6-(1H-tetrazol-5-yl)-4,4′-dimethyl-2,2′-bipyridine), have been synthesized and characterized. Complex 2 adopts a distorted square-planar geometry with a mono-anionic terdentate chelate tmbpy, and it presents a zigzag head-to-tail stacking array along the a axis with alternating Pt⋯Pt separations of 3.415 and 5.469 Å. For 2, a moderately intensive broad absorption band appears at 350–425 nm in dilute DMF solution, most likely assigned as the metal-to-ligand charge transfer ¹MLCT (Pt(5d) → tmbpy) transition, mixed with some halide-to-ligand charge transfer ¹XLCT (Cl → tmbpy) and intraligand (IL) ¹ππ* transitions inside tmbpy. It is demonstrated that the solubilities and luminescence properties of 1 and 2 are markedly influenced by the substituents in the 4 and 4′-positions of the 2,2′-bipyridyl ring. The solid-state emissions of 1 and 2 are perhaps best attributable to the ³MMLCT/³XLCT/³IL states, as supported by TD-DFT calculation of 2.     

Syntheses,structures and magnetic property of two copper complexes with cyclic dimer and 2D herringbone-like network built from helical motif

Two copper(II) complexes, Cu₂{3,5-(NO₂)₂sal}₂(2,2′-bipy)₂ · 0.5H₂O (1) and [Cu₂{3,5-(NO₂)₂sal}₂(4,4′-bipy)(H₂O)₂]_n (2) (3,5-(NO₂)₂sal = 3,5-dinitrosalicylate, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), were synthesized by hydrothermal reactions and characterized by single crystal X-ray analysis. There are discrete cyclic binuclear structure in 1 and 2D herringbone-like network structure in 2, although bridging ligand 3,5-(NO₂)₂sal in 1 and 2 has same coordination model. Variable temperature magnetic measurement reveals small ferromagnetic interactions in complex 1.     

A palladium(II) complex of 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine: Lattice control through an interplay of stacking and hydrogen bonding effects

The complex [Pd(1)Cl]Cl where 1 =  4′-(4-pyridyl)-2,2′:6′,2″-terpyridine is reported. The single crystal structure of [Pd(1)Cl]Cl · 3H₂O · DMF features rows of columns of [Pd(1)Cl]⁺ cations which are supported by Pd⋯Pd interactions (3.367(1) and 3.440(1) Å) and separated by hydrogen-bonded 4.8² nets of water molecules and Cl⁻ ions.     

Luminescent homodinuclear copper(I) halide complexes based on the 3,5-bis{6-(2,2′-dipyridyl)}pyrazole ligand

Two novel mixed-ligand dicopper(I) halide complexes, [{Cu(PPh₃)X}₂(μ-HL)] (HL = 3,5-bis{6-(2,2′-dipyridyl)}pyrazole, X = I (1); Br (2)), have been synthesized by a straightforward double-layer diffusion approach and structurally characterized by single-crystal X-ray diffraction. The multi-site HL acts as a bridging bis-bidentate chelate, assembling two Cu(PPh₃)X moieties into copper(I) dimers possessing the triple-decker “organic” sandwich structure of phenyl/pyrazolyl/phenyl through π···π interactions. Complexes 1 and 2 exhibit photoluminescence in the solid state at ambient temperature, ascribed to a combination of intraligand charge transfer (ILCT) and metal-to-ligand charge transfer (MLCT) transitions. The emission of 2 is red-shifted 18 nm relative to that of 1 due to substitution of the iodides of 1 by the weaker electron-donating bromides.     

Hydrothermal synthesis and structure of di-copperII-complex substituted monovacant polyoxotungstate with a 1D chain structure

A novel di-copper^II-complex substituted monovacant Keggin polyoxotungstate [Cu(2,2′-bpy)(H₂O)][H₂PW₁₁O₃₉Cu₂(2,2′-bpy)₂(H₂O)(OH)] · 1.5H₂O (1) (2,2′-bpy = 2,2′-bipyridine) with a 1D polymeric chain has been hydrothermally synthesized and structurally characterized. To our knowledge, 1 is the rare magnetic di-transition metal-complex substituted monovacant Keggin polyoxotungstate with a unique 1D dual-bridging chain structure. Its magnetic behavior has been quantitatively analyzed by the Bleaney–Bowers equation, indicating the presence of weak antiferromagnetic interactions within dinuclear Cu^II centers.     

The novel ligand 4′-phenyl-3,2′:6′,3′′-terpyridine (L) and the supramolecular structure of the dinuclear complex [Zn2(μ-L)(acac)4] · H2O (acac = acetylacetonato)

The new terpyridyl ligand 4′-phenyl-3,2′:6′,3′′-terpyridine (L) reacts with Zn(acac)₂ to produce the dizinc complex [Zn₂(μ-L)(acac)₄] · H₂O (1) (acac = acetylacetonato). The analysis of the crystal structure of this zero-dimensional (0D) complex shows the existence of two Zn(acac)₂ centers bridged symmetrically by one μ-L ligand. The key role played by the acac and L ligands and the guest water molecule allows the generation of a series of intermolecular hydrogen bonds of the O–H/O, C–H/O and C–H/π type which give raise to a 3D supramolecular array. The observed C–H/π interactions are so widespread that all the π-rings present in the structure, viz., those belonging to the L ligand as well as the acetylacetonato chelate rings, participate as hydrogen bond acceptors.     

Hydrothermal syntheses and crystal structures of PbII coordination polymers based on a N,O-donor ligand

In this article, four new lead(II) coordination polymers based on a N,O-donor ligand 2′-(1 H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-yl)biphenyl-2-carboxylic acid (HL) have been hydrothermally synthesized, namely, [PbL₂]·2H₂O (1), [PbL₂]·2H₂O·CH₃CH₂OH (2), [Pb₅L₂(m-BDC)₄]·3H₂O (3) and [Pb₂L₂(p-BDC)] (4), where m-BDC = 1,3-benzenedicarboxylate and p-BDC = 1,4-benzenedicarboxylate. Compound 1 shows a 2D bilayer structure, which is further extended into a 3D supramolecular structure through π–π stacking interactions. Compound 2 shows a 3D supramolecular structure based on a zero-dimensional molecule by π–π stacking interactions of neighboring molecules. Compound 3 shows a 2D layer structure. Compound 4 displays a 1D chain-like structure, which is then stacked by π–π interactions to result in a 2D supramolecular structure. Solid-state luminescent spectra of four lead(II) complexes indicate intense fluorescent emissions.     

Two d10 coordination polymers based on 4,4′-(hexafluoroisopropylidene)diphthalic acid: Syntheses,structures and physical properties

Two novel coordination polymers, [Zn₂(FA)(4,4′-bipy)₂]·2H₂O (1) and Cd₂(FA)(2,2′-bipy) (2), (H₄FA = 4,4′-(hexafluoroisopropylidene)diphthalic acid, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine), have been synthesized under hydrothermal conditions, and their structures were determined by single-crystal X-ray diffraction. Polymer 1 features an unusual three-dimensional (3D) network with (4 · 6² · 8³)(4² · 6² · 8²) topology. Polymer 2 has a complicated 3D framework and crystallizes in non-centrosymmetric space group (Fdd2) belonging to polar point group (C_2v), which displays a strong SHG response and ferroelectric properties. Moreover, the luminescent properties of 1 and 2 have also been investigated.     

The crystal structure of 2′,6′-dichloro-4-dimethylaminoazobenzene

A monoazo dye, 2′,6′-dichloro-4-dimethylaminoazobenzene (C₁₄H₁₃Cl₂N₃) was synthesized and characterized by X-ray diffraction, IR, ¹H NMR, and elemental analysis. The title molecule crystallizes in the monoclinic system space group P2₁/c (#14), a = 10.782(1), b = 8.9610(9), c = 15.108(2) Å, β = 103.008(5)°, V = 1422.2(3) Å³, Z = 4. The title molecule is not planar and takes trans-geometry and the two phenyl rings are twisted around the central linkage in opposite directions. In the crystal, molecules are interacted through π⋯π interaction, forming ‘double chains’ along [1 −1 0]. The ‘double chains’ are extended along [001] through H-Bond C11–H6⋯Cl2, C5–H3⋯Cl1 forming double layers (110), which are in turn interacted by C3–H1⋯Cl1 H-Bond [010], forming crystals. The molecular geometry has been calculated using the ab initio restricted Hartree–Fock and density functional method (B3LYP) with 6-311G** basis set. The optimized geometric parameters obtained by two methods are similar and in good agreement with the experimental values.     

Temperature dependence of dual emission in ruthenium(II) complexes containing 3,3′-bi-1,2,4-triazine derivatives

Three new ruthenium(II) polypyridyl complexes with highly π-deficient ligands, [Ru(bpy)₂(btm)]²⁺ (1), [Ru(bpy)₂(btb)]²⁺ (2) and [Ru(bpy)₂(btp)]²⁺ (3) (bpy = 2,2′-bipyridine, btm = 3,3′-bis(5,6-dimethyl-1,2,4-triazine, btb = 3,3′-bis(5,6-diphenyl-1,2,4-triazine, btp = 3,3′-bis(phenanthro[9,10-e][1,2,4]triazine) were synthesized and characterized. Electrochemical data together with molecular calculations show that the first redox process in these complexes is not bpy based. Complexes 1, 2 and 3 display luminescence in ethanol/methanol (4/1, V/V) at 80 K, and all three complexes exhibit a temperature switch from single (150 K) to dual (80 K) emission behavior.     

Fluorescent selectivity for small molecules of two coordination polymers based on a tetracarboxylate ligand

Two coordination polymers [Cd(tptc)_0.5(4,4′–bibp)]_n (1) and {[Zn₃(Htptc)₂(phen)₂]·1.5H₂O}_n (2) (H₄tptc = terphenyl-3,3″,5,5″-tetracarboxylic acid, 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl, and phen = 1,10-phenanthroline) were synthesized under solvothermal conditions. Complex 1 displays a 3D structure with a Schläfli symbol of {4⁴.6²}{4⁸.6²⁰}. Complex 2 possesses a 2D layer network, incorporating [Zn₃(COO)₆] second building units (SBUs), which is packed into a 3D supramolecular architecture by π ⋯ π interactions. Both of them exhibit strong luminescence characteristics. It is worth to note that complexes 1 and 2 show potential application to detect small organic molecules.     

Syntheses and structures of cadmium(II) and cobalt(II) coordination polymers based on 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) and carboxylate ligands

Two novel coordination polymers containing Cd(II) and Co(II) metals, connected via 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) (L) ligand, have been synthesized. Compound [Cd(L)₂(p-BDC)] · 2H₂O (1) (p-BDC = 1,4-benzenedicarboxylate anion) is a three-dimensional interdigitated supramolecular architecture. Compound [Co(L)(BTCA)_0.5] (2) (BTCA = 1,2,3,4-butanetetracarboxylate anion) possesses a unique (3,4)-connected 3D framework with (8³)₂(8⁵ · 10) topology.     

Two 2-D 4-connected lanthanide coordination framework based on benzimidazole-5,6-dicarboxylate and acetate mixed ligands

Two 2-D polymers, [Ln(bidc)(Ac)·H₂O]_n (Ln = Tb(1), Dy(2) H₂bidc = benzimidazole-5,6-dicarboxylic acid, HAc = acetic acid), have been successfully synthesized under hydrothermal conditions at 150 °C and characterized by elemental analysis, infrared spectra and single-crystal X-ray diffraction. Single crystal X-ray diffraction analyses reveal that the two compounds are isomorphous and exhibit one new (4,4)-connected 2-nodal (4⁴·6²)(4⁴·6²) layer-like net, stabilized by the interchain hydrogen bonding N–H?O, O–H?O and π?π stacking interactions between two benzimidazole rings. 2-D layers are further connected by the interlayer O–H?O hydrogen-bonding interactions to form a 3-D supermoleculaer network. Moreover, the luminescent property of compound 1 and thermogravimetric analyses of the two complexes 1–2 are discussed in detail.     

Syntheses,structures, and luminescent properties of zinc(II) complexes assembled with aromatic polycarboxylate and 1,3-bis(1,2,4-triazol-1-yl)propane

Three new coordination compounds, {[Zn(btrp)(ip)]?2H₂O}_n (1), {[Zn(btrp)(hip)]?2H₂O}_n (2), and {[Zn_1.5(btrp)(btc)(H₂O)]?H₂O}_n (3) (btrp = 1,3-bis(1,2,4-triazol-1-yl)propane, H₂ip = isophthalate, H₂hip = 5-hydroxy isophthalate, H₃btc = benzene-1,3,5-tricarboxylic acid) have been prepared via solvothermal method and characterized by single crystal X-ray diffraction and elemental analysis. 1 possesses 2D (4. 4) net framewok. 2 is also a 2D infinite layer framework, and the resulting 2D structure is interconnected by hydrogen-bond and π…π interactions to lead to a 3D supramolecular architecture. 3 exhibits a novel 2D framework with three nonequivalent points, {5.6²}{5².6}{5⁴.8²}. The fluorescence properties of 1–3 have been studied at room temperature.     

Two novel grid networks based on Keggin-type polyoxometalate clusters assembled through weak Cu⋯O interactions

Two novel grid networks based on Keggin-type polyoxoanion, formulated [Cu(2,2′-bipy)₂](HPMo₁₂O₄₀) · H₂O (1) and [Cu(2,2′-bipy)₂](HPW₁₂O₄₀) · H₂O (2) have been synthesized hydrothermally and characterized by elemental analyses, IR, EPR and X-ray single crystal diffraction. 1 is a 2D grid network built by the interconnection of bisupporting polyoxoanion clusters assembled through weak Cu⋯O interactions. The EPR spectrum of 1 indicates that its unpaired electrons are placed in d_x²−y² orbital of the ground state of Cu(II). Compound 2 is isostructural with compound 1.     

Metal-controlled assembly of coordination polymers: Structural variation from 2D parallel interpenetration to 3D CsCl-type topology

Two novel metal-organic frameworks [Cd₂(hdb)₂(1,4-ndc)₂]_n (1) and [Ni₃(Hhdb)₂(1,4-ndc)₄(H₂O)₂]_n (2) have been synthesized under the similar hydrothermal conditions (hdb = 1,1′-(1,6-hexanediyl)bis(imidazole) and 1,4-ndc = 1,4-naphthalenedicarboxylate). The polymers (1) and (2) show 2D parallel interpenetration and 3D CsCl-type topology, respectively, which are mainly affected by the differences of the metal centers.