A new two-dimensional manganese(II) coordination polymer with alternating double end-on and single end-to-end azido bridges: Crystal structure and magnetic properties

A new azido-bridged Mn(II) coordination polymer, [MnL(N₃)₂]n (1) (L = (E)-3-(dimethylamino)-1-(pyridin-2-yl)prop-2-en-1-one), has been synthesized and characterized by elemental analysis, IR, single crystal X-ray diffraction and magnetic measurement. X-ray analysis shows that complex 1 is a 2D network with (6, 3) layers, in which double end-on (EO) azido-bridged dimers are linked by single end-to-end (EE) azido bridges. Magnetic susceptibilities of 1 were measured under a magnetic field of 2 KOe applied over the temperature range 300–1.8 K. The analysis of magnetic data indicates that the EO- and EE-azido bridges mediate the ferromagnetic and antiferromagnetic exchange interactions, respectively, with the antiferromagnetic coupling between Mn(II) ions dominating the magnetic properties of 1.     

Spin-canting in a 1D chain Mn(II) complex with alternating double end-on and double end-to-end azido bridging ligands

A new one-dimensional (1D) azido-bridged manganese(II) complex, [Mn(dpq)(N₃)₂]_n [dpq = dipyrido-(3,2-d:2′,3′-f)-quinoxaline] (1), was synthesized and characterized. Crystal structure study reveals that 1 contains a 1D manganese(II) chain bridged by alternating double end-to-end (EE) and double end-on (EO) azido ligands. The strong interchain π–π stacking interaction extends the structure into a 2D supramolecular array. The analysis of magnetic data indicates that the EO- and EE-azido bridges mediate the ferromagnetic and antiferromagnetic interactions, respectively. Interestingly, complex 1 exhibits a weak ferromagnetic property below 6 K probably due to spin canting.     

Two nickel coordination polymers with flexible ligand 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene

The reaction of 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) with Ni(II) salts yields two coordination polymers [Ni₃(ttmb)₂(H₂O)₆Cl₆](H₂O)₃ (1) and [Ni(ttmb)₂(H₂O)₂](NO₃)₂(H₂O)₄ (2). The flexible ligand ttmb shows the cis,cis,cis-conformation and a tri-monodentate coordination mode in 1. Each ttmb links three Ni(II) atoms to form an undulated (3, 4)-connected two-dimensional network. Each undulated two-dimensional network polycatenates other two identical networks, thus giving a rare (2D → 3D) parallel polycatenation network in 1. The ttmb ligand exhibits the cis,trans,trans-conformation and a two-monodentate coordination mode in 2. Each ttmb connects two Ni(II) atoms to construct a two-dimensional (4, 4) network in 2. The thermal stability of compounds 1 and 2 was studied.     

Syntheses,structures and luminescence of three copper(I) cyanide coordination polymers incorporating flexible N-donor ligands

Three copper(I) cyanide coordination polymers, namely [Cu₈(CN)₈(btmb)₂]_n (1), [Cu(CN)(btmb)_0.5]_n (2) and [Cu₂(CN)₂(dpa)]_n (3) (btmb = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, dpa = di(4-pyridyl)amine), were synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, PXRD and thermogravimetric analyses. Single-crystal X-ray diffraction analyses reveal that complex 1 is an interesting 2D double-layered network constructing from eight distinct Cu(I) centers, eight μ₂-cyanides and two tetradentate cis-btmb ligands. Complex 2 is a ladder-like coordination polymer assembled by CuCN linear chain and bidentate trans-btmb linker. Complex 3 has a 2D wave-like network constructing from CuCN zigzag chain and V-shape dpa spacer. These coordination polymers are thermally stable up to 270–300 °C. They emit blue luminescence originating from ligand-centered emission.     

Tuning structural topologies of two coordination polymers via alter N-donor auxiliary ligand

Based on the N-donor auxiliary ligand effect, two new Ni(II) coordination polymers [Ni₂(HL)₂(bpe)₂] (1) and [Ni(HL)(bipy)(H₂O)₂] (2) [H₃L = 2-(4′-carboxyphenyl)terephthalic acid; bpe = 1,2-bis(4-pyridyl)ethane; bipy = 4,4′-bipyridine] have been successfully synthesized and characterized by single-crystal X-ray diffraction study, elemental analysis, IR spectra, TGA and powder X-ray diffraction (PXRD). This work presents a comparative study on the tuning of structural topologies by using two N-donor ligands with different lengths as auxiliary ligands. The structural determination reveals that complex 1, incorporating bpe ligands, features a three-dimensional (3D) 4-connected 4-fold dia interpenetrating architecture with the point symbol of 6⁶, while 2, containing bipy ligands, exhibits a two-dimensional (2D) sql layer structure with a 4-connected (4⁴·6²) topology. Moreover, the magnetic properties for 1 and 2 were also measured and compared on account of their different structures.     

Syntheses,characterizations, and redox behaviors of new self-assembled metal complexes with bridging ligands incorporating chalcogen sites

Three new complexes, [Zn(dbsf)₂(dmf)₂] · 5.5dmf (dbsf = 4,4′-sulfonyldibenzoate) (1β), [Cu(tdsa)(phen)₂] · 1.5EtOH (tdsa = 5,5′-thiodisalicylate, phen = 1,10-phenanthroline) (2), and [Cu(sdp)(phen) · Cu(Hsdp)(phen)(CH₃COO)] · 3EtOH (sdp = 4,4′-sulfonyldiphenolate) (3) were prepared and structurally characterized. Complex 1β shows a one-dimensional coordination framework constructed from bridges between Zn(II) centers with two ligands. Complex 2 is a monomeric complex, which assembles by π–π interactions. Complex 3 shows a unique two-dimensional coordination framework that is constructed from two Cu(II) centers, sdp, and Hsdp. The redox properties of these three complexes were characterized by solid-state cyclic voltammetry. Complexes 1β and 3 show irreversible reduction waves because of the reduction of their sulfone sites. Complex 2 shows an irreversible oxidation wave because of oxidation of the sulfide site.     

A copper coordination polymer based on bis(imidazole) and thiophenedicarboxylate for photocatalytic degradation of organic dyes under visible light irradiation

The copper(II) coordination polymer [Cu₂(bix)(sdc)₂]_n (1) was synthesized by the hydrothermal method (bix = 1,4-bis(2-methyl-imidazol-1-ylmethyl)benzene, sdc = 2,5-thiophenedicarboxylate). The copper(II) atom of 1 shows unsaturated square-pyramidal configuration. 1 exhibits the 2-fold interpenetrating three-dimensional pcu network based on the [Cu₂(COO)₄] dimers. 1 is an efficient and universal photocatalyst for the degradation of the organic dyes methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) under visible light irradiation, and is very stable and can be reused.     

Two 2D metal–organic frameworks based on 2,2′-bibenzimidazole ligand with (6,3) net topology

Two 2D metal–organic frameworks (MOFs), {[Zn₄(Hbbim)₄(bbim)₂] 2H₂O}_n (1) and [Cd₂(Hbbim)₂(bbim)]_n (2) (H₂bbim = 2,2′-bibenzimidazole) were obtained by solvothermal reaction and characterized by single crystal X-ray diffraction analysis. Different metal ions, Cd(II)/Zn(II), adopt very different coordination geometries though two title compounds both have a 2D honeycomb network with (6,3) topology. The frameworks of compounds 1 and 2 are stable below 360 °C and 475 °C, respectively. Solid-state luminescent spectroscopy of compound 2 exhibits an emission peak at 407 nm.     

A lead(II)-orotate coordination polymer with a new coordination mode: Synthesis,structure and luminescent property

A lead(II) orotate complex [Pb(HOr)(H₂O)]_n (1), (H₃Or = orotic acid) was synthesized under hydrothermal condition and characterized by X-ray diffraction, IR, solid-state photoluminescence and thermogravimetric analysis. Lead atom in 1 is in a holodirected eight-coordinated polyhedron and the orotate ligand exhibits a new and unique hexametallic coordination mode. The lead complex shows a 6,6-connected (4⁸, 6⁶, 8)(4¹³, 6²) topology. The complex exhibits photoluminescence at 546 nm (λ_ex = 350 nm).     

Construction and photoluminescence properties of two novel zinc(II) and cadmium(II) benzyl-tetrazole coordination polymers

Two new d¹⁰ coordination polymers, Zn(Beta)₂ (1) and Cd₂(Beta)₃Cl(H₂O) (2) (Hbeta = 5-benzyl-tetrazole) have been synthesized by the in situ [3 + 2] cycloaddition reaction of 5-benzylacetonitrile, sodium azide and MCl₂ [M = Zn (1); M = Cd (2)] under hydrothermal condition. Complex 1 is a coordination polymer comprised of numerous mildly undulated two-dimensional (2D) layers with a (4, 4) topological network; while complex 2 is a 3D coordination framework constructed from the interconnection of various helical chains through cadmium–chlorine bridges. Furthermore, the luminescence properties of two complexes have been investigated.     

Syntheses,crystal structures and magnetic property of two azido-bridged coordination polymers with 1,2-diaminocyclohexane as co-ligand

Two azido-bridged coordination polymers, [Ni(L)(μ_1,1-N₃)₂] (1) and [Cu(L)(μ_1,1,3-N₃)(N₃)] (2) (L = 1,2-diaminocyclohexane), have been synthesized and characterized by elemental analyses, IR spectra and X-ray structural analyses. Complex 1 is a one-dimensional helical chain coordination polymer with both azides as μ_1,1-bridge, which exhibits interesting wheel motif. Complex 2 shows two-dimensional layer network in which an azide acts as μ_1,1,3-bridge and the other azide as monodentate ligand. Cyclic voltammogram gives quasi-reversible redox wave of Cu(II)/Cu(I) pair. Variable-temperature magnetic property of 1 was investigated, which shown strong ferromagnetic interaction arising from the μ_1,1-azido bridging nickel(II) chains.     

An inclined interpenetrating heteropolynuclear polymer with unusual propagation of metal carboxylate secondary building units by both carboxylate and pyridyl bridging ligands

The objective of this paper is to describe an unusual coordination polymer, M₄(μ₄-O)(bipy)(m-BDC)₃ (sM₄ = Zn_2.36 Co_1.64, bipy = 4,4′-bipyridine, m-H₂BDC = 1,3-benzenedicarboxylic acid) (1), which has been hydrothermally synthesised and characterized by single-crystal X-ray diffraction, XRPD, IR, TGA, ICP, atomic absorption, and element analysis. 1 crystallizes in the P4₂/mnm space group and contains a M₄O(O₂C)₆ secondary building unit (SBU) with an inclined interpenetrated (4, 4) topology, and is a rare combination of the two most successful approaches to coordination polymer design: generation of metal carboxylate SBUs and the use of pyridyl donor bridges. Moreover, complex 1 exhibits intense fluorescence at about 424 nm (λ_ex = 312 nm) in the solid state.     

A novel two-dimensional square grid cobalt complex: Synthesis,structure, luminescent and magnetic properties

A novel cobalt(II) coordination polymer, [Co(L)₂]_n (1) (HL = 4-(imidazol-1-yl)-benzoic acid), has been hydrothermally synthesized and structurally characterized by X-ray diffraction, IR spectrum and elemental analyses. Structure determination of complex 1 reveals that the two-dimensional (2D) network framework consists of regular square grid with dimensions of ca. 11.42 × 11.42 Å. Complex 1 exhibits a strong blue luminescence centering at 409 nm in the solid. Variable temperature magnetic susceptibility study shows there is a weak antiferromagnetic interaction in complex 1. Thermal property is also investigated.     

Diversity of carboxylate coordination in two novel zinc(II) cinnamate complexes

Two novel mixed-ligand zinc(II) complex compounds [Zn(cinn)₂(mpcm)]_n (1) and [Zn(p-HO-cinn)₂(nia)(H₂O)₂] · H₂O (2) (cinn = cinnamato, mpcm = methyl-3-pyridylcarbamate, nia = nicotinamide) were prepared and characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction and thermal analysis. Diverse modes of carboxylate coordination were found in the complexes. In 1 the cinnamate ligands coordinate as monodentate and bridging (syn–anti), respectively. The syn–anti carboxylate bridges connect the molecules of 1 to infinite polymeric helical chains. The structure of 2 is monomeric. One of the carboxylate oxygens of p-hydroxycinnamate is semi-coordinated (Zn–O = 2.549(2) Å).     

A two-dimensional copper polymer constructed from rod-shaped ferromagnetic secondary building units

On the basis of rod-shaped secondary building units (SBUs), a novel two-dimensional (2D) azide–copper polymer, [Cu₃(N₃)₄(anol)₂]_∞ (1; anol = aminoethanol), was synthesized and structurally characterized. Complex 1 is a neutral 2D coordination network consisting of trinuclear copper(II) clusters [Cu₃(N₃)₄(anol)₂] connected with the bridge of end-end (EE) azide group. Magnetic data analysis shows that a metamagnetic behavior is observed for 1 which is associated with significant ferromagnetic coupling intracluster over 4 K.     

Three-dimensional fivefold interpenetrating microporous metal–organic framework based on mixed flexible ligands

The chiral diamondoidlike Cd(II) containing coordination polymer {[Cd(oba)(bib)]·2H₂O}_n (1) (oba = 4,4′-oxybis(benzoate), bib = 1,4-bis(2-methyl-imidazol-1-yl)butane) is reported; the 3D networks interpenetrate fivefold, nevertheless leave cavities capable of including sizable guest molecules. This compound also exhibits high thermal stability and blue-shift emission, and can be explored for potential blue luminescent materials.     

A Michael-type reaction between acrylato ions and ethylenediamine coordinated to Ni(II). Synthesis,crystal structure and magnetic properties of [Ni2(EDDP)2(H2O)2] · 2H2O (H2EDDP = ethylenediamine-N,N-dipropionic acid)

The reaction between NiCO₃ · Ni(OH)₂, acrylic acid and ethylenediamine in a 2:4:1 molar ratio affords the binuclear complex, [Ni₂(EDDP)₂(H₂O)₂] · 2H₂O 1. The organic ligand, EDDP^2? (the dianion of the ethylenediamine-N,N-dipropionic acid ligand), results from the addition of one amine group to the carbon–carbon double bonds of two acrylato ions. The crystal structure of 1 consists of neutral centrosymmetric entities, with the nickel ions connected by two carboxylato groups, each one acting as a monoatomic bridge. The intramolecular Ni?Ni distance is 3.212 Å. The metal ions exhibit an octahedral geometry. The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the nickel(II) ions (J = ?21.8 cm^?1, H = ?JS_Ni1S_Ni2).     

Two helical one-dimensional copper(II) coordination polymers based on N-(2-hydroxylbenzyl)glycine and N-(2-hydroxylbenzyl)-l-alanine: Syntheses,crystal structures and magnetic studies

Two new helical Cu(II) coordination polymers, [Cu(2,2′-bpy)(Hsgly)]Cl · 2H₂O(H₂sgly = N-(2-hydroxylbenzyl)glycine) (1) and [Cu(2,2′-bpy)(Hsala)](NO₃) · 2H₂O(H₂sala = N-(2-hydroxylbenzyl)-l-alanine) (2) were synthesized. Single crystal X-ray diffraction analysis indicated that both complexes showed helical chains arrangement of Cu(II) centers bridged by carboxyl groups. The magnetic measurements showed complex 1 exhibited ferromagnetic interaction while there was no interaction between the Cu(II) centers in complex 2.     

Tunable dual-emissive photoluminescence of a zinc(II) coordination polymer based on tetrazolate-carboxylatate acid and 4,4′-bipyridine mixed organic chromophores

Herein, we presented an in-situ hydrothermally synthesized photoluminescent zinc(II) coordination polymer (Zn–CP), namely [Zn₂(tzeba)₂(bpy)]_n1, in which H₂tzeba = 3-(1-tetrazol-ethyl)benzoic acid, bpy = 4,4′-bipyridine. Compound 1 exhibits ligand-centered photoluminescence (PL) and displays interesting dual emissions based on the excitation of different chromophores from the mixed organic ligands. The PL colors of 1 could be tuned from blue-to-cyan-to-green directly by varying the excitation wavelengths. The PL mechanism has been investigated by the density of states (DOS) and density functional theory (DFT) calculations.     

A novel three-dimensional cadmium(II) coordination polymer constructed from dinuclear molecular building block,syntheses, structure and photoluminescence property

A novel cadmium(II) coordination polymer, [Cd₂(pzdc)₂(4,4′-bpy)₂]·4H₂O (1) (H₂pzdc = pyrazine-2,3-dicarboxylic acid; 4,4′-bpy = 4,4′-bipyridine), has been synthesized by hydrothermal reaction of Cd(OAC)₂, H₂pzdc and 4,4′-bpy. Single-crystal X-ray diffraction analysis reveals that 1 constructed from dinuclear building blocks has a three-dimensional (3-D) structure with rob topology. Fluorescent measurement of 1 exhibits strong blue-green emission in the solid state at room temperature, and its framework possess remarkable thermal stability.