Preparation, crystal structure and properties of two novel metal-organic frameworks assembled from pyridine-3,5-dicarboxylic acid N-oxide

Two novel coordination polymers, [Cu(PDCO) · (H₂O)]_n (1) and [Cd(PDCO)(bipy) · (H₂O) · 5H₂O]_n (2), (H₂PDCO = pyridine-3,5-dicarboxylic acid N-oxide, bipy = 4,4′-bipyridine), have been synthesized under hydrothermal conditions, and their structures were determined by single-crystal X-ray diffraction studies. Polymer 1 features a three-dimensional (3D) network with nonequivalent nodes of (6³)₂(6⁹ · 8⁵ · 10) topology. Polymer 2 exhibits one-dimensional (1D) double-stranded chains. The magnetic character of 1 as well as the gas adsorption and luminescent properties of 2 have been investigated.     

Anion-directed assembly of two novel cadmium(II) complexes constructed by 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) ligand

Depending on the different coordinated anions used, reaction of Cd(II) salt with 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) results in the formation of two coordination polymers: a 1D chain {[Cd(H₂C4BIm)Cl₂] · (H₂C4BIm)}_n (1), and a 2D sheet [Cd(HC4BIm)(NCS)]_n (2) which features distorted 4.8² topology (H₂C4BIm = 2,2′-(1,4-butanediyl)bis(1H-benzimidazole)). The fluorescence properties for both the complexes have been studied.     

A peculiar heterotrimetallic Mn–Co–Ni complex: Synthesis, crystal structure and magnetic properties

The first complex [Mn(H₂O)₆][NiCo(TTHA)(H₂O)₂] · 4H₂O 1 (TTHA⁶⁻ = triethylenetetraminehexaacetate) containing Mn^II–Co^II–Ni^II three different 3d metal ions is synthesized and magnetic measurement suggests that ferromagnetic interactions occur between Ni²⁺ ions and rarely found low-spin Co²⁺ ions.     

Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

Cu(II) bipyridine and phenantroline complexes: Tailor-made catalysts for the selective oxidation of tetralin

Mononuclear Cu(II) complexes have been synthesized, and their structure thoroughly characterized by electrospray ionization mass spectrometry (ESI-MS). These 2,2′-bipyridine and 1,10-phenantroline mononuclear Cu(II) complexes have been tested as catalysts in the partial oxidation of tetralin (1,2,3,4-tetrahydronaphthalene), using hydrogen peroxide as oxidant in acetonitrile/water as solvent.The complexes [Cu(bipy)₃]Cl₂·6H₂O (1), [Cu(bipy)₂Cl]Cl·5H₂O (2), [Cu(bipy)Cl₂] (3), [Cu(phen)₃]Cl₂·6H₂O (4), [Cu(phen)₂Cl]Cl·5H₂O (5), [Cu(phen)Cl₂] (6) were able to oxidize tetralin at room temperature, at high degrees of conversion (62.1% with 2) into α-tetralol and α-tetralon at 91% selectivity (81% in 1-tetralon).Depending on nature and number of ligands (bipyridine or phenantroline) surrounding Cu²⁺ cation, one was able to tailor both the activity toward tetralin oxidation, and the selectivity toward 1-tetralol and 1-tetralone products, but also to raise the yield in valuable α-tetralone.     

Controllable assembly of a 3-D metal–organic supramolecular framework with the inclusion of a well-resolved 1-D water morph

Two mixed-ligand metal–organic complexes [Cd₂(adipato)(phen)₂(NO₃)₂(H₂O)₂](H₂O)₆ (1) and {[Cd(adipato)(phen)](H₂O)₃}_n (2) have been synthesized upon the reaction of Cd(II) nitrate with 1,10-phenanthroline (phen) and adipate under similar conditions. For 1, the adipato-bridged dinuclear entities are extended into a 3-D supramolecular architecture via hydrogen bonds and π–π stacking. Interestingly, a well-resolved 1-D water morphology consisting of alternate cyclic water tetramer and hexamer is detected as the guests in each channel of this 3-D lattice. Whereas 2 represents a layered coordination polymer in which the Cd^II centers are interlinked by adipate dianions via different coordination modes.     

Structure and magnetic properties of a copper malonate/dipyridylamine layered coordination polymer with both syn–anti and anti–anti copper carboxylate chains

The novel 2-D copper metal–organic layered coordination polymer {[Cu₂(malonate)₂(dpa)(H₂O)₂] · H₂O} (1, dpa = 4,4′-dipyridylamine) has been prepared and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The structure of compound 1 consists of alternating syn–anti and anti–anti copper malonate 1-D chains linked into a (6,3) herringbone layer motif through tethering dpa ligands. Variable temperature magnetic studies indicate weak ferromagnetic coupling through the 1-D copper malonate chains with J = 0.64(1) cm⁻¹ and g = 2.033(4).     

Solvothermal synthesis of a novel mixed valence Cu(I)/Cu(II) complex containing sulphate, malate and 4,4-bipyridine, [CuCu2(mal)(SO4)(bpy)2 · H2O]n. Unique binding mode of the malate anion

The reaction of CuSO₄ · 5H₂O with 4,4^′-bipyridine and malic acid at 140 °C under solvothermal conditions afforded a mixed valence three-dimensional coordination polymer [Cu^ICu^II₂(mal)(SO₄)(bpy)₂ · H₂O]_n, (1). The building unit consists of a Cu²⁺-dimer in which copper centers are bridged by malate and sulphate anions. SO₄²⁻ anion further connects dimeric unit with the Cu¹⁺ center. Building units are linked by 4,4^′-bipyridine ligands to form double chains, that are interconnected into 3D network through additional sulphate bridge.     

1-D and 2-D lanthanide coordination polymers constructed from 4-sulfobenzoate and 1,10-phenanthroline

Two complexes {[Dy₂(4-SBA)₃(phen)₂(H₂O)₄] · 2H₂O}_n (1) and {[Eu₂(4-SBA)₃(phen)₂(H₂O)₂]}_n (2) (4-SBA = 4-sulfobenzoate, phen = 1,10-phenanthroline) were synthesized and their structures were determined by X-ray crystallography. The 1 has a 1-D chain structure by bidentate and tridentate 4-SBA ligands as linkages and 3-D network was formed by strong hydrogen bonds. The 2 has a 2-D network structure by tridentate and tetradentate 4-SBA ligands as linkages. The luminescence properties and thermal stability of the two complexes were investigated.     

Synthesis and structural characterization of new one-dimensional rhodium complexes

New one-dimensional Rh^I–Rh^II complexes [Rh₂(OOCMe)₂(phen)₂]_n(PF₆)_n·0.5nMe₂CHOH, 1 and [Rh₂(OOCMe)₂(bpy)₂]_n(PF₆)_n·nH₂O, 2 have been synthesized and characterized. The compound 1 is molecular wire with the shortest Rh(I)–Rh(II) distances, anions and solvate molecules occupy channels between parallel cationic wires.     

Bimetallic nickel complexes of trimethyl phenyl linked salicylaldimine ligands: Synthesis, structure and their ethylene polymerization behaviors

Bimetallic salicylaldimine-nickel complexes, 2,4,6-Me₃-1,3-{[NCH–(3′-R-5′-Y-2′-O–C₆H₃)-κ²-N,O]Ni(Ph) (PPh₃)}₂ [R = tert-Bu, Y = Me, 1b; R = Ph, Y = H, 2b] were prepared and their catalytic behaviors of ethylene polymerization were investigated. The bimetallic complex 2b shows higher activities (2.9 × 10⁵ g PE mol⁻¹ Ni h⁻¹) for ethylene polymerization and affords polymer with high molecular weight (M_w = 1.41 × 10⁵) and broad molecular weight distribution (M_w/M_n = 6.1) than its mononuclear matrix, {[(2,6-Me₂C₆H₃)–NCH–(3′-Ph-2′-O–C₆H₃)-κ²-N,O]Ni(Ph)(PPh₃)} (3) (Activity = 5.5 × 10⁴ g PE mol⁻¹ Ni h⁻¹; M_w = 1.86 × 10⁴; M_w/M_n = 2.8).     

Synthesis and structural characterization of an alternating double aquo-bridged and single cyano-bridged polymeric barium–iron complex: {[Ba2(phen)4(H2O)6Fe(CN)6]·Cl·2(phen)·3H2O}n

A new alternating double aquo-bridged and single cyano-bridged polymeric complex {[Ba₂(phen)₄(H₂O)₆Fe(CN)₆]·Cl·2(phen)·3H₂O}_n (1) (phen = 1,10-phenanthroline) has been synthesized and structurally characterized. In the crystal structure the two centrosymmetric [Ba₂(phen)₄(H₂O)₆] units are bridged through two trans CN groups of [Fe(CN)₆]³⁻ ion, which results in the formation of a zig-zag polymeric chain. In each [Ba₂(phen)₄(H₂O)₆] unit, the two Ba centers are joined by double aquo bridges. Both the Ba atoms are 9-coordinated with distorted mono-capped square antiprismatic geometry. An elaborate hydrogen bonding system holds the parallel polymeric chains together.     

A novel 3D double helix cobalt(II) coordination polymer: Synthesis, crystal structures and third-order non-linear optical properties

One new metal-organic complex formulated as {[Co(bipy)₃][Co₂(μ₂–ox)₃]}_n 1 (bipy = 2,2′-bipyridyl; ox = oxalate) has been synthesized by low-temperature solid-state reaction and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and UV–visible spectra. The complex 1 contains helical chains composed of left-handed and right-handed helices interlaced in pairs. The third-order non-linear optical (NLO) properties of the 1 were also investigated and they exhibit the reverse saturable absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 5.75 × 10⁻³⁰ esu for 1 in a 2.36 × 10⁻⁴ mol dm⁻³ DMF solution.     

A new binuclear potassium (І) complex with a novel 1D infinite water chain containing (H2O)12 clusters

A novel 1D infinite water chain made of (H₂O)₁₂ clusters containing two different chair water hexamers is found in the binuclear coordination compound, [K₂(L)₂(phen)₄]·6H₂O (1) (where L = 2,2′-azanediyldibenzoic dianion, phen = 1,10′-phenanthroline), which has been synthesized and structurally characterized by single-crystal X-ray diffraction. The fluorescence spectrum and thermogravimetric analysis (TGA) of the title complex 1 have been also discussed.     

Self-assembly of a 1D helical manganese coordination polymer and a tetranuclear lanthanum complex with 1,10-phenanthroline and 3,5-dinitrosalicylato dianion

The hydrothermal reaction of manganese chloride and lanthanum nitrate with 3,5-dinitrosalicylic acid (3,5-(NO₂)₂sal) and 1,10-phenanthroline (phen) yielded two compounds [Mn(phen){3,5-(NO₂)₂sal²⁻}]_n (1) and La₂(phen)₃{3,5-(NO₂)₂sal²⁻}₂ (NO₃)(OH) (2). Magnetic susceptibility measurements show weak antiferromagnetic interactions in (1).     

Solvothermal synthesis of 1D and 2D cobalt(II) and nickel(II) coordination polymers with 2,5-dihydroxy-p-benzenediacetic acid

1D cobalt(II) and nickel(II) coordination polymers {[Co(dba)(H₂O)₄] · H₂O}_n (1) and {[Ni(dba)(H₂O)₄] · H₂O}_n (2) (H₂dba = 2,5-dihydroxy-p-benzenediacetic acid) were synthesized under low temperature solvothermal condition. When 4,4′-bipyridine (bpy) was introduced to the synthetic systems of 1 and 2, respectively, two novel 2D coordination polymers {[Co(dba)(bpy)] · 0.5H₂O}_n (3) and [Ni(dba)(bpy)(H₂O)₂]_n (4) with different structures were obtained. All of the compounds were characterized by elemental analysis, FT-IR, UV–Vis spectra and single crystal X-ray diffraction.     

Thermal and chemical stability of Cu–Zn–Cr-LDHs prepared by accelerated carbonation

Layered double hydroxides Cu_xZn_6 − xCr₂(OH)₁₆(CO₃)·4H₂O with different molar ratios of Cu/Zn/Cr were synthesized by accelerated carbonation. The products were characterized by XRD, SEM, FT-IR and TG-DTG-DSC-MS. The chemical stability was tested by the modified Toxicity Characteristic Leaching Procedure (TCLP). The results showed that the products were the mixture of Cu_xZn_6 − xCr₂(OH)₁₆(CO₃)·4H₂O and (CuZn)₂(CO₃)(OH)₂, with similar thermal behavior. All products were chemically stable with reduced leaching at pH > 6 (Cu²⁺, Zn²⁺) or > 5 (Cr³⁺).     

Phenanthroline–manganese inclusion complexes of dicarboxylic acid containing extensive hydrogen-bonding interactions

Two phenanthroline–manganese inclusion complexes with [MnCl(H₂O)(phen)₂]⁺ core were prepared in the presence of dicarboxylic acid and their structures were determined. Uncoordinated adipic acid and phthalic acid as guest molecules are included in the complexes with formulas {[MnCl(H₂O)(phen)₂]Cl}₂·C₆H₁₀O₄·8H₂O (1) and {[MnCl(H₂O)(phen)₂]Cl}₄·2C₈H₆O₄·4H₂O (2). The dicarboxylic acid molecules together with aqua and Cl⁻ ligands, Cl⁻ anions and solvate H₂O molecules form extensive hydrogen-bonding interactions, building up supramolecule-like aggregate structure.

Graphical Abstract

Dicarboxylic acid is enclosed in the host structure of [(C₁₂H₈N₂)MnCl(H₂O)]⁺ to form two inclusion compounds containing adipic acid and phthalic acid, respectively. Extensive hydrogen-bonding interactions were observed.

Full-size image (8K)

 

Zigzag on a zigzag: Trap of hydrogen-bonded water molecules in a luminescent metal–organic network

A four-connected 2-D metal–organic coordination polymer {[Cd(mpdc)(phen)] · H₂O}(mpdc = 2,6-dimethylpyridine-3,5-dicarboxylate, phen = 1,10-phenanthroline) has been assemblied from cadmium ions and two kinds of organic ligands under hydrothermal conditions, characterized by single-crystal X-ray diffraction analysis. The 2-D metal–organic network was constructed from binuclear [Cd(O₅N₂)]₂ clusters bridged by mpdc²⁻ ligands. The most interesting is that water molecules trapped by the 2-D network look as if its motif is projected from the zigzag arrangement of cadmium atoms in the 2-D network via hydrogen bonding interactions. In addition, new compound exhibits strong luminescence at λ_max = 525 nm upon excitation at 367 nm.     

Synthesis, structure and magnetic properties of the first copper(II) complex with an (E)-4-aryl-4-oxo-2-butenoato ligand

A new binuclear Cu(II) complex with an (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato ligand (L) was successfully synthesized and characterized by elemental analysis and IR-spectroscopy. The structures of (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoic acid (HL), and the corresponding (tetrakis)-μ-[(E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato]-bis(ethanol)-copper(II) complex, [Cu₂L₄(C₂H₅OH)₂], were determined by single crystal X-ray analyses and are preliminarily discussed. This is the first complex of a transition metal with ligand L, as well as the first determined crystal structure of a metal complex with this type of ligand. Analysis of the magnetic susceptibility measurements of the isolated [Cu₂L₄(C₂H₅OH)₂] · H₂O complex shows the existence of a strong anti-ferromagnetic intradimer coupling, with an exchange integral value 2J of −260 cm⁻¹.