Two new d10 2D layered frameworks based on 1,2,4-triazole bridge: Syntheses,structures, and fluorescence

Two new triazole-bridging d¹⁰ 2D layered frameworks, [Cd(H₂O)₂(Httr)₂](SiF₆) (1), [Zn(ttr)(OAc)] (2) (Httr = 3-amino-1H-1,2,4-triazole), were synthesized with structures and fluorescence characterized. 1 is based on a kind of 16-membered ring with μ₂-1 κN:4 κN coordination mode of Httr and 2 is constructed from the fuse of different 6- and 16-membered rings with μ₃-1 κN:2 κN:4 κN mode of ttr⁻. The hydrogen bondings in 1 and 2 between the anions and ttr connect the 2D layers into 3D supramolecular architectures. The fluorescent studies of compounds 1 and 2 show an important difference, emission at 460 nm in 1 and a dual one at 334 and 462 nm in 2.     

Syntheses,characterization and properties of manganese,cobalt and copper complexes from chelate N-donor ligands

2-[(S)-4-isopropyl-2-oxazolyl]quinoline (L¹) and 2-[(S)-4-phenyl − 2-oxazolyl]quinoline (L²) react with manganese, cobalt and copper salts to yield four new complexes: [Mn₂(L¹)₂]Cl₂ (1), {[Co(L¹)₂]₂(OH)}(ClO₄)₃ (2), [Cu₂I₂(L¹)₂] (3), and {[Cu(L²)₂]₂(OH)}(BF₄)₃·H₂O (4), which were fully characterized by single-crystal and powder X-ray diffraction, IR, elemental and thermogravimetric analyses. Complexes 1–4 all show dinuclear structure. Two metal ions are bridged by Cl⁻ in 1, by OH^– in 2 and 4, and by I⁻ in 3. Moreover, non-linear optical, and ferroelectric and magnetic properties have been investigated.     

Homochiral iron(II) complexes based on imidazole Schiff-base ligands: Syntheses,structures, and spin-crossover properties

A pair of mononuclear iron(II) enantiomeric complexes: fac-Λ-[Fe(R-L)₃](BF₄)₂·MeCN (1) and fac-Δ-[Fe(S-L)₃](BF₄)₂·MeCN (2) [L = 1-phenyl-N-(1-methyl-imidazol-2-ylmethylene)ethanamine] have been synthesized and characterized. X-ray crystallography reveals that iron(II) center is surrounded by three bidentate ligands defining a pseudooctahedral [FeN₆] coordination environment. R-L ligand induces the fac-Λ isomer, while S-L ligand induces the fac-Δ isomer. Magnetic measurements reveal that both of them display obviously spin-crossover behavior at 365 K. After desolvation, they exhibit a reversible spin transition with a small hysteresis loop of ca. 3 K appearing at about T_1/2↑ = 222 K and T_1/2↓ = 219 K.     

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.     

Structural diversity and distinct photoluminescent properties of two new lanthanide-copper (I) frameworks based on mixed isonicontinate/oxalate ligands

Although several heterometallic Ln(III)–Cu(I) compounds with mixed isonicotinate(IN)/oxalate(Ox) ligands are known, only one kind of framework structure is established to date. It is inconceivable for such a complex four-component system. Two new Ln(III)–Cu(I) compounds [DyCu(IN)₂(Ox)·H₂O]_n (1) and [EuCu(IN)₂(Ox)·3H₂O]_n (2) with distinct structural features and photoluminescent properties are successfully synthesized under hydrothermal conditions. The results demonstrate the structural diversity of such a mixed four-component system.     

Two rod-based 3-D lead(II) tetrafluoroterephthalate coordination frameworks with sra topology: Syntheses, structures, and properties

Two three-dimensional (3-D) Pb^II coordination frameworks [Pb(BDC-F₄)(CH₃OH)]_n (1) and [Pb(BDC-F₄)(DMF)(CH₃OH)]_n (2) have been prepared by the reactions of Pb(NO₃)₂ with a rigid dicarboxyl compound tetrafluoroterephthalic acid (H₂BDC-F₄) in different solvents. Single crystal X-ray diffraction reveals that both complexes show the unusual rod-based coordination networks with sra topology, although they crystallize in different space groups (C2/c and ). Their spectroscopic, thermal, and fluorescence properties have also been studied.     

Syntheses,structures and photoluminescence properties of two 2D Cd(II) coordination polymers based on a semirigid tridentate N-donor ligand

The assembly of a semirigid tridentate N-donor ligand with Cd(II) ions afforded two novel coordination polymers, [Cd(tipa)(H₂O)₂·2NO₃·2DMF·H₂O]_n (1), [Cd₂(tipa)₂Cl₄·2DMF·6H₂O]_n (2), where tipa = tris(4-(1H-imidazol-1-yl)phenyl) amine. Structural analyses indicate that the two compounds feature 2D layered networks. A 3-connected uninodal net with point symbol of (8²·10) is constructed in compound 1 by the connection of tipa and metal ions, in which the terminally coordinated water molecules prevent further extension of the layer. Compound 2 features [Cd₂Cl₄] motifs, which are bridged by tridentate tipa ligands into a 2D (3,6)-connected layer. The results show that tipa with different dihedral angles between benzene ring and terminal imidazole groups can act as versatile building blocks for the generation of various networks. Moreover, the photoluminescence properties of 1 and 2 in the solid state at room temperature have been investigated.     

Two novel Cd(II)-based coordination polymers constructed from isomeric double betaine ligands: Syntheses,structures and fluorescent properties

Two novel Cd^2 + based coordination compounds based on two isomeric double betaine ligands (1,4-Bis(4-carboxylatopyridinium-1-methylene)benzene (H₂L₁Cl₂) and 1,4-Bis(3-carboxylatopyridinium-1-methylene)benzene (H₂L₂Cl₂)) were synthesized, structurally and optically characterized. Both compounds show two dimensional sheet architectures with different features depending on structural motifs that ranging from helical chain to linear chain, and the spatial arrangements of coordinated ligands as well as their unlike coordination modes. They further exhibit the way how three dimensional supramolecular isomers form via weak interactions. Meanwhile, two compounds exhibit intense fluorescence attributing to the ligands' emissions with stokes shift.     

Syntheses,structures and magnetic properties of two Dy6 clusters based on polydentate ligands with a new topological motif

Two novel analogous Dy₆ complexes were synthesized in low-temperature reactions and characterized via X-ray crystallographic and magnetic measurements. Structural analysis revealed the resulting complexes form a new topological motif for hexanuclear dysprosium clusters. Magnetic studies indicated the two complexes are both ferromagnetic interactions and exhibit magnetization relaxation behavior.     

Syntheses,structures and magnetic properties of multinuculear manganese complexes with Schiff base ligands

Multinulear manganese complexes with Schiff base ligands, [{Mn^III₄(μ₃-O)(sae)₄(μ-N₃)(CH₃OH)}₂(μ-N₃)]N₃ ([1]N₃), [Mn^III₆(μ₃-O)₂(sae)₆(NCS)₂] (2) and [Mn^II₄Mn^III₂(sae)₆(CH₃OH)₂Cl₂] (3) (H₂sae=2-salicylideneaminoethanol), were prepared and the crystal structures and magnetic properties were studied.     

Three d10 coordination polymers based on rigid ligands with flexible functional groups: Syntheses,structures and luminescence

Three coordination polymers, namely, {[Zn(L)(BPY)]·DMF·H₂O}_n (1), {[Zn(L)(TPY)]·0.5H₂BDC·H₂O}_n (2), {[Cd(L)(H₂O)₂]·DMF}_n (3), have been synthesized based on a rigid linear carboxylate ligand (H₂L = 2′,5′-dimethoxy-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylic acid) and different lengths of pyridine ligands (TPY = 4,3′:5′,4″-terpyridine; BPY = 4,4′-bipyridine). These complexes have been characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. Complex 1 is a 6-connected 3-fold interpenetrating pcu net with point symbol {4¹² ∙ 6³}, 2 and 3 can be simplified as 4-connected sql nets with point symbol {4⁴ ∙ 6²}. In addition, their photoluminescent properties are also investigated in detail.     

Two novel self-interpenetrating 3D iron(II) coordination frameworks: Synthesis,spectroscopic and structural characterizations with magnetic properties

Two novel self-interpenetrating 3D Fe(II) coordination frameworks namely {Fe(4,4′-bpy)[Ag₂(CN)₃]₂}_n (I) and {Fe(4,4′-bpy)[Ag(CN)₂]₂[AgCN]₂}_n (II) have been synthesized and fully characterized. The 3D architectures and degree of interpenetration of these coordination frameworks were significantly affected by silver(I) cyanide species. The crystal structure of I presents 4-fold interpenetrating 3D framework with 4,4′-bpy and [Ag₂(CN)₃]⁻ species. While, that of II constructed by 4,4′-bpy and two different silver(I) cyanide species, AgCN and [Ag(CN)₂]⁻ resulting to 2-fold interpenetrating 3D framework. The stability and rigidity of both coordination frameworks are mainly supported dominantly by Ag^I ⋯ Ag^I interactions. Their magnetic properties exhibit high spin behavior.     

Syntheses,crystal structures,spectroscopy, and catalytic properties of two nickel-based hexaazamacrocyclic complexes with carboxylate ligands

Two new hexaazamacrocyclic nickel(II) complexes with the formula [NiL¹(4-nba)₂] (1) and [NiL²(sal)₂] (2) (L¹ = 3,10-dioctyl-1,3,5,8,10,12-hexaazacyclotetradecane, L² = 3,10-diisobutyl-1,3,5,8,10,12-hexaazacyclotetradecane, 4-nba = p-nitrobenzoate, and sal = salicylate) were synthesized at room temperature. These complexes were characterized by physico-chemical and spectroscopic methods as well as single-crystal X-ray diffraction analysis. The coordination geometry in complexes 1 and 2 exhibit a distorted octahedron around the nickel(II) ion with hexaazamacrocyclic unit in the equatorial positions and two p-nitrobenzoate (or salicylate) anions in the axial positions. The degradation of methyl orange by potassium persulfate (KPS) in the presence of complex 1 (or 2) oxidation system occurred to near completion in 60 min compared to only 55% with KPS alone under UV light irradiation. Thus, both complexes in cooperation with KPS could be an attractive choice for degradation of organic pollutants for environmental remediation.     

Two novel 3D self-threading coordination polymers with CdSO4 topology: Syntheses,structures and properties

Two new isostructural metal-organic frameworks, namely [Co(HL)(bpp)] · 0.5H₂O (1) and [Zn(HL)(bpp)] · 3H₂O (2) (H₃L = 5-(2′-carboxy-biphenyl-4-ylmethoxy)-isophthalic acid, bpp = 1,3-bis(4-pyridyl)propane), have been hydrothermally synthesized and further characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, IR spectra and TG analyses. Compounds 1 and 2 exhibit interesting 3D frameworks of (6⁵.8)-CdSO₄ topology with dangling arm (i.e. the uncoordinated 2′-carboxy-biphenyl-4-ylmethoxy group of HL ligand). The remarkable feature of these two compounds is that each dangling arm threads into two 6-membered rings belonging to the 3D net itself, displaying the self-threading character. The magnetic properties of 1 and photoluminescence of 2 have also been investigated.     

Syntheses,structures, and magnetic properties of ethoxy-bridged dinuclear iron(III) complexes containing tetradentate ligands

Dinuclear iron(III) complexes, [(phenO)Fe(SO₄)]₂·2CH₃OH (1) and [(bpmapO)Fe(NO₃)]₂(NO₃)₂·3CH₃OH (2) have been prepared by the reaction of phenOH/bpmapOH and FeSO₄·7H₂O/Fe(NO₃)₃·9H₂O in methanol, respectively (phenOH = N-(2-pyridylmethyl)-N′-(2-hydroxyethyl)ethylenediamine, bpmapOH = N-(bis(2-pyridylmethyl)amino)-2-methylpropan-2-ol). Both complexes are ethoxy-bridged dinuclear species and the iron(III) ions in 1 and 2 have distorted octahedral geometries. Both complexes show strong antiferromagnetic interactions through the bridged ethoxy groups within the dimeric units.     

Two Keggin polyoxoanion-based hybrids composed of CuI/tbz segments: Syntheses,structures and electrochemical properties

Two Keggin polyoxoanion-based hybrid compounds composed of Cu^I/tbz segments [Cu^I₂(tbz)₂][Cu^I(tbz)₂(PMo^VI₁₀Mo₂^VO₄₀Cu^I₂)] (1) and [Cu^I₂(tbz)₃][Cu^I (tbz)₂](PW₁₂O₄₀) (2), have been hydrothermally synthesized. In compound 1, a 3D supramolecular framework with 2D channels is constructed from a novel cap-to-cap {Cu^I(tbz)₂(PMo^VI₁₀Mo₂^VO₄₀Cu^I₂)}^2 −_n chain via hydrogen bonding and π–π interactions, in which {Cu^I₂(tbz)₂}^2 + segments are incorporated. Compound 2 is composed of one discrete PW₁₂ polyoxoanion, one {Cu^I(tbz)₂}⁺ segment and one {Cu^I₂(tbz)₃}^2 + segment, displaying a 3D supramolecular structure through hydrogen bonding and π–π interactions. The results indicate that the polyoxoanions and configurations of tbz ligand play the key roles in the self-assembly processes. The electrochemical properties of compounds 1 and 2 have been investigated.     

Two d10 Coordination Polymers Based on the Substitutional Aromatic Multicarboxylate and N-donor Co-ligands: Syntheses, Structures and Luminescent Properties

Two new coordination polymers, formulated as Zn(3-NPA)(1,4-bimb) (1) and Cd(3-NPA)(1,2-bimb)(H₂O) (2) (3-NPAH₂?=?3-nitrophthalic acid, 1,4-bimb?=?1,4-bis(imidazol-1 -ylmethyl)benzene, 1,2-bimb?=?1,2-bis(imidazol-1-ylmethyl)-benzene) have been synthesized by hydrothermal reactions of the semirigid neutral ligand 1,4-bimb or 1,2-bimb with metal ions in the presence of 3-nitro phthalic acid. The two compounds were characterized by infrared spectroscopy, elemental analysis, thermo gravimetric analysis and single-crystal X-ray diffraction analysis. Polymer 1 possesses a new two-dimensional puckered rectangular grid architecture, with the 1,4-bimb ligands displaying a cis-conformation. In polymer 2, the 3-NPA^2? anions coordinate the Cd(II) ions in a tetra dentate mode to form a dimer unit, which is connected by the 1,2-bimb ligands resulting in a single layer. Intra layer hydrogen bond interactions are found between the water molecule and carboxylate oxygen atoms. Weak π···π interactions are observed between the layers through the benzene rings from the adjacent 3-NPA^2? and 1,2-bimb ligands. In addition, the luminescent properties of the two compounds were also investigated in this paper.     

Two Cd(II) coordination polymers based on 3,6-bis(imidazol-1-yl)carbazole: Syntheses,structures and photocatalytic properties

Hydrothermal reactions of CdCl₂·2.5H₂O with 3,6-bis(imidazol-1-yl)carbazole (bmcz), 2-amine-1,4-benzenedicarboxylic acid (2-NH₂-1,4-H₂BDC) or 1,4-naphthalenedicarboxylic acid (1,4-H₂NDC) afforded two coordination polymers, [Cd(2-NH₂-1,4-BDC)(bmcz)]_n (1) and [Cd(1,4-NDC)(bmcz)]_n (2). Complexes 1 and 2 were characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. 1 and 2 are isomorphic and exhibit 3D supermolecular structures. The solid state luminescent and optical properties of 1 and 2 at ambient temperature were also investigated. A comparative study on their photocatalytic activity toward the degradation of methylene blue in polluted water was explored.     

Syntheses,topological analyses and magnetic properties of two 3D supramolecular nickel-organic frameworks constructed from 1,3,5-benzenetricarboxylate and flexible imidazole-based ligands

Two supramolecular nickel-organic frameworks, [Ni(HBTC)(bix)]_n (1) and [Ni₃(BTC)₂(mbix)₃(H₂O)₄]_n · 6nH₂O (2) (bix = 1,4-bis(imidazole-l-yl-methyl)benzene, mbix = 1,3-bis(imidazole-l-yl-methyl)benzene, and H₃BTC = 1,3,5-benzenetricarboxylate), have been hydrothermally prepared by the assembly of H₃BTC, Ni²⁺ with bix or mbix. Compound 1 shows a 2D layer structure, whose 3D supramolecular structure exhibits a fsc topology when hydrogen-bonging interactions between the adjacent layers are taken into account. Compound 2 manifests an unprecedented 2D (3, 4)-connected topological net. The 3D supramolecular framework of 2 is formed through π?π stacking interactions between the adjacent layers. The magnetic studies show that 1 features overall ferromagnetic property whilst 2 presents strong zero-field splitting (ZFS) when treated as a mononuclear model. Furthermore, the IR and TGA properties of 1 and 2 were also studied.