Six isostructural lanthanide-containing MOFs built on a semi-rigid tripodal organic ligand

By using a semi-rigid tripodal ligand 1,1′,1′′-(2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)tripyridinium-4-olate) (L), six isomorphous lanthanum metal-organic frameworks (MOFs), namely, [Pr(L)₂(Cl)₂]·(Cl)(DMF)_0.5·(H₂O)·(1), [Nd(L)₂(Cl)₂]·(Cl)(2), [Tb(L)₂(Cl)₂]·(Cl)·(DMF)·(H₂O)(3), [Eu(L)₂(Cl)₂]·(Cl)(DMF)·(H₂O)(4), [La(L)₂(Cl)₂]·(Cl)(5), [Sm(L)₂(Cl)₂]·(Cl) (DMF)·(H₂O) (6), were obtained and characterized by single crystal X-ray diffraction, IR and elemental analysis. Six compounds are isostructural with Ln^3 + (Ln = Pr, Nd, Tb, Eu, La, Sm) and in which the Ln^3 + is considered as a 6-connecting node and the L ligand is a 3-connecting node to afford a (3,6)-connected 2D layer with kgd topology, which further stacks into 3D supramolecular networks through C-H^…O weak interactions. Luminescent properties of these lanthanide MOFs have also been assessed at ambient temperature, in which the Pr^3 +-1 and the La^3 +-5 are slightly blue-shifted with respect to the ligand. Series of sharp peaks characteristic of the Eu^3 +-4, the Tb^3 +-3 and Sm^3 + − 6 metal-centered luminescence appear. The Nd^3 +-2 has no emission.     

Structures and magnetism of bimetallic octacyanometallates: honeycomb-like [Mo(CN)8Ni2(pn)4]n·4nH2O and binuclear [Mo(CN)8Ni(en)2(H2O)][Ni(en)3]·2H2O (pn=1,3-diaminopropane,en=1,2-diaminoethane)

Bimetallic octacyanometallates [Mo(CN)₈Ni₂(pn)₄]_n·4nH₂O (1) and [Mo(CN)₈Ni(en)₂(H₂O)][Ni(en)₃]·2H₂O (2) based on [Mo(CN)₈]⁴⁻ were synthesized in aqueous solution, and their crystal and molecular structures have been determined. The complex [Mo(CN)₈Ni₂(pn)₄]_n·4nH₂O (1) consists of novel two-dimensional honeycomb-like layers. The complex [Mo(CN)₈Ni(en)₂(H₂O)][Ni(en)₃]·2H₂O (2) contains a binuclear anion [Mo(CN)₈Ni(en)₂(H₂O)]²⁻,[Ni(en)₃]²⁺ cation and two lattice water molecules. Magnetic studies suggest a possible weak antiferromagnetic interaction between Ni²⁺ ions in 1.     

Heteroleptic chromium(III) tris(diimine) [Cr(N^N)2(N′^N′)]3 + complexes

A series of heteroleptic tris(diimine) complexes of chromium(III) is reported and the crystal structures of {4[Cr(bpy)₂(phen)][PF₆]₃}·11MeCN and 4[Cr(4,4′-Me₂bpy)₂(bpy)][PF₆]₃}·12MeCN·H₂O are described. The combined effects of a 1:3 cation: anion ratio and lattice solvent molecules are discussed, in particular in the context of the influence on intercation embraces. The presence of the methyl substituents in {4[Cr(4,4′-Me₂bpy)₂(bpy)][PF₆]₃}·12MeCN·H₂O results in Me–π_bpy contacts becoming the dominant packing interactions and in the assembly of motifs distinct from those in {4[Cr(bpy)₂(phen)][PF₆]₃}·11MeCN.     

Syntheses,crystal structures and luminescent investigations of cobalt(II) and zinc(II) complexes with 2-propyl-4,5-dicarboxylate-imidazole (H3PIDC)

Presented in this communication are four metal complexes based on 2-propyl-4,5-dicarboxylate-imidazole (H₃PIDC), including two Co(II) coordination compounds, [Co(H₂PIDC)₂(H₂O)₂] · 4H₂O (1) and 2[Co(H₂PIDC)₂(H₂O)₂] · 5H₂O (2), as well as two Zn(II) coordination compounds, [Zn(H₂PIDC)₂(H₂O)₂] · 4H₂O (3) and 2[Zn(H₂PIDC)₂(H₂O)₂] · 7H₂O (4). They contain the same coordinated unit of [M(H₂PIDC)₂(H₂O)₂] (M = Zn or Co). Interestingly, among these four complexes, 1 and 2, or 3 and 4 crystallized in different space group, which may be related with the number of the crystallized H₂O molecules.     

Novel oligonuclear ZnII4, ZnII8 and ZnII2NiII2 complexes with bis(benzoylacetone)-1,3-diiminopropan-2-ol

Reactions of bis(benzoylacetone)-1,3-diiminopropan-2-ol (abbreviated as H₃L) with zinc salts in the presence of triethylamine afforded the compounds [Zn₄(HL)₄]·4CH₃CN (1·4CH₃CN) and [Zn₈L₄(OH)₄]·2CH₃CN (2·2CH₃CN). Further reaction of 1 with Ni(CH₃COO)₂·4H₂O gave the heteronuclear species [Zn₂Ni₂(L)₂(CH₃O)₂(CH₃OH)₂] (3). The crystal structures of 1·4CH₃CN, 2·2CH₃CN and 3 were determined by the X-ray diffraction method.     

Copper(II) and cadmium(II) complexes with an imide tethered imidazole and a copper(II) coordination polymer through ring opening reaction

The reactions of 2-(3-(1H-imidazol-1-yl)propyl)isoindoline-1,3-dione (L) with copper (II) chloride or copper(II) nitrate resulted in mononuclear complexes [CuL₄Cl₂]·12H₂O (1) or [CuL₄(H₂O)NO₃]NO₃·2H₂O (2) respectively; whereas the copper(II) acetate reacted with L to give a three dimensional coordination polymer {[Cu(L′)₂]·4H₂O}n (3), (where L′ = 2-(3-(1H-imidazol-1-yl)propylcarbamoyl)benzoate). The reaction of cadmium(II) acetate with L led to the formation of a seven-coordinated complex [CdL₃(O₂CCH₃)₂]·2H₂O (4).     

Dehydration,Water Vapor Adsorption and Desorption Behavior of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3]

The dehydration behaviors of two different hydrated zinc borate species, Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B₃O₃(OH)₅] · H₂O from air at 25°C. However, Zn[B₃O₄(OH)₃] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.     

Salen Type Sandwich Triple-Decker Tri- and Di-nuclear Lanthanide Complexes

Four N,N′-bis(salicylidene)-1,2-(phenylene-ediamine) (H₂L) trinuclear lanthanide complexes, namely, [Ln₃L₃(CH₃OH)₂(NO₃)₃]·(CH₂Cl₂)·(CH₃OH)·(H₂O)₂ [Ln = Tb (1), Ho (2), Er (3) and Lu (4)], have been isolated by the reactions of H₂L and Ln(NO₃)₃·6H₂O. And one N,N′-bis(salicylidene)-1,2-(phenylene-ediamine) dinuclear neodymium complex [Nd₂L₃(CH₃OH)] (5) has been harvested from the reaction of H₂L with Nd(OAc)₃·4H₂O. X-ray crystallographic analysis reveals that complexes 1?4 are of triple-decker trinuclear sandwich structure, while complex 5 is of a triple-decker dinuclear sandwich structure, expanding upon the recent reports of the multinuclear pure lanthanide complexes.     

Azametallacrowns with aza18-MC-6 and aza12-MC-4 motifs constructed by phenolicpyrazoles: Syntheses,structures, and magnetic properties

Two new manganese azametallacrowns [Mn₆(L)₆(OH)₆]·(DMF)₃ and [Mn₄(L)₄(OH)₄]·(H₂O)·(Py)₃ (H₂L = 2-[5-Pyridin-2-yl-1-H-pyrazol-3-yl]-phenol) with aza18-MC-6 and aza12-MC-4 structural motifs were obtained and characterized by X-ray single crystal diffraction, element analysis, IR and XRD. The magnetic studies reveal the ferromagnetic interactions and field-dependent slow magnetization relaxation in aza18-MC-6, as well as the dominant antiferromagnetic coupling in aza12-MC-4.     

A new cyano-bridged Ca(II)–Fe(III) complex containing both molecular square and linear trimetallic species

A new cyano-bridged Ca(II)–Fe(III) complex, [Ca₂(phen)₄(H₂O)₆Fe(CN)₆][{Ca(phen)₂(H₂O)₂Fe(CN)₆}₂]·3(phen)·(phenH)·14H₂O·CH₃OH (where phen=1,10-phenanthroline) 1 has been synthesized and structurally characterized. It contains a cyano-bridged trimetallic cationic species [Ca₂(phen)₄(H₂O)₆Fe(CN)₆]⁺ 1a with a nearly linear Ca–Fe–Ca arrangement, and an anionic species [{Ca(phen)₂(H₂O)₂Fe(CN)₆}₂]²⁻ 1b which has a cyano-bridged tetrametallic Ca–Fe–Ca–Fe molecular square framework. In both the species, the Ca atoms are eight coordinated with distorted anti-squareprismatic geometry and the Fe atoms have six coordinated octahedral geometry. The charge is balanced by the protonation of one phen molecule in the lattice.     

Terbium-oxalate-pyridinedicarboxylate coordination polymers suggesting the reductive coupling of carbon dioxide (CO2) to oxalate (C2O42−):[Tb2 (3,5-PDC)2(H2O)4(C2O4)]·2H2O and [Tb(2,4-PDC)(H2O)(C2O4)0.5] (PDC = pyridinedicarboxylate)

Under hydrothermal conditions, Tb(NO₃)₃·5H₂O reacted with 3,5-pyridinedicarboxylic acid (3,5-PDCH₂) to give a 3-D coordination polymer with the empirical formula of [Tb₂ (3,5-PDC)₂(H₂O)₄(C₂O₄)]·2H₂O (1). Tb(NO₃)₃·5H₂O also reacted with 2,4-pyridinedicarboxylic acid (2,4-PDCH₂) to give another 3-D coordination polymer [Tb₂ (2,4-PDC)₂(H₂O)₂(C₂O₄)] (2). The structures of both polymers have been determined by X-ray diffraction. X-ray structure analyses show that both polymers contain bridging oxalate (C₂O₄²⁻) ligands, which might have been formed by the reductive coupling of CO₂ molecules released from the PDC²⁻ ligands through the C–C bond cleavage.     

A novel organic/inorganic hybrid nanoporous material incorporating Keggin-type polyoxometalates

Tree novel nanoporous compounds, [Cu₃(TMA)₂(H₂O)₃]₄[{(CH₃)₄N}₂(H₂SiMo₁₂O₄₀)] ·≈40H₂O (1), [Cu₃(TMA)₂(H₂O)₃]₄[{(CH₃)₄N}₂(HPW₁₂O₄₀)] ·≈40H₂O (2), and [Cu₃(TMA)₂(H₂O)₃]₄[{(CH₃)₄N}₂(HPMo₆W₆O₄₀)] ·≈40H₂O (3) (TMA=acidtrimesic acid=1,3,5-benzentricaboxylate) have been synthesized via hydrothermal process, and characterized by X-ray structure analysis, IR and NMR spectroscopy, and thermogravimetry. All the compounds crystallize isostructurally consisting of a nanoporous coordination polymer framework [Cu₃(TMA)₂(H₂O)₃]_n accommodating α-Keggin polyoxomolybdate and -tungstate anions. Results of the IR and ²⁹Si and ³¹P MAS NMR spectra reveal the existence of α-Keggin species with no other impurity.     

A New Metal–Organic ZnII Supramolecular Assembled via Hydrogen Bonds and N···N Interactions as a New Precursor for Preparation Zinc(II) Oxide Nanoparticles, Thermal, Spectroscopic and Structural Studies

A new 1D supramolecular involving two different ligands, {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O (GB = 2-guanidinobenzimidazole and bpe = 1,2-bis(4-pyridyl)ethylene, has been synthesised, characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR spectroscopy. The thermal stability of compound {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O was studied by thermal gravimetric and differential thermal analyses. The single crystal X-ray analysis shows that the complex is a one-dimensional polymer involving macrocycle rings as a result of non-covalent bridging bpe ligands via N–H···N and N···N interactions, N–H···bpe···bpe···H–N, with the basic repeating {[Zn(GB)₂](μ-bpe)₃}(ClO₄)₂·H₂O units and by connecting [Zn(GB)₂]²⁺ nodes. ZnO nanoparticles were obtained by calcination of compound {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O at 500 °C in air. The nanoparticles were characterized by X-ray diffraction and scanning electron microscopy.     

Two Energetic Cobalt(II) Coordination Polymers Derived from Isomeric Ligands

Isomer is sometimes fundamental to the formation of the resulting compounds. The design and preparation of coordination compounds based on isomers is of tremendous paramount since they have a lot in common but simultaneously some difference, which can lead to variation of both the topologies and properties. Solvothermal reactions of Hn-pytza (n = 3, 4) with Co(ClO₄)₂·6H₂O, afforded two interesting coordination polymers, one dimensional [Co(3-pytza)₂(H₂O)₂]_n·2nH₂O (1) and three dimensional [Co(4-pytza)₂]_n (2), where Hn-pytza = 5-(n-pyridyl)tetrazole-2-acetic acid (n = 3, 4). The thermal decomposition behavior of the two compounds were characterized by the differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG), showing [Co(4-pytza)₂]_n is superior to [Co(3-pytza)₂(H₂O)₂]_n·2nH₂O in terms of energetic performance. Furthermore, the entropy of activation (?S), enthalpy of activation (?H), and free energy of activation (?G) were calculated, as well.     

A Novel 3D Photoactive Coordination Polymer with Alternate Cd(H<Subscript>2</Subscript>O)<Superscript>2+</Superscript> and Mg(Hen)<Superscript>3+</Superscript> Units and Sandwich-Shaped Cluster Linkages

A novel organic–inorganic hybrid, cadmium(II)-magnesium(II)-molybdenum(V) phosphate, {Cd[(PO₄)₂(HPO₄)₂Mo₆O₁₁(OH)₄]₂}[Cd(H₂O)]₂[Mg(Hen)]₂{Cd[(PO₄)₃(HPO₄)Mo₆O₁₀(OH)₃Cl₂]₂}·(H₂en)₄·(Hen)₂·(en)₂·9H₂O (en = ethylenediamine), was prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, inductively coupled plasma (ICP) analysis, thermogravimetric analysis, fluorescence, FT-IR and bond valence sum calculations. As revealed by single-crystal X-ray diffraction studies, the sandwich-shaped clusters of [Cd(Mo₆P₄)₂] are interconnected by additional [Mg(Hen)] units and [Cd(H₂O)] fragments to form an extended three-dimensional supramolecular framework with channels occupied by ethylenediamine molecules, protonated ethylenediamine cations and water molecules. Luminescent measurement of the title compound exhibits intensive blue and greenish-blue radiation emission upon excitation with ultraviolet light.     

Hydrothermal syntheses,crystal structures and photocatalytic properties of three POM-templated organic–inorganic hybrid compounds

Three new POM-templated organic–inorganic compounds, Cu₂(3,5-bptp)₂[H₂SiW₁₂O₄₀]·4H₂O (1), Ag₂(3,5-bptp)₂[HPW₁₂O₄₀]·4H₂O (2), [Cu₄(OH)₃Cl(H₂O)₃(4-bpo)₃](SiW₁₂O₄₀)·5H₂O (3) (3,5-bptp = 3,5-bis(3-(pyrid-4-yl)-1,2,4-triazolyl)-pyridine, 4-bpo = 2,5-bis(4-pyridyl)-1,3,4-oxadiazole) were hydrothermally synthesized and characterized by elemental analysis and single crystal X-ray diffraction. Crystal structural analysis indicates that compounds 1 and 2 are isostructural and show one dimensional zigzag chains with [H₂SiW₁₂O₄₀]^2 − as guest molecules. Compound 3 is two dimensional sheets constructed from [Cu₄(OH)₃Cl(H₂O)₃] clusters and 4-bpo ligands with [SiW₁₂O₄₀]^4 − as guest molecules. Furthermore, the photocatalytic degradation of methyl orange (MO) with 3 was studied under visible light irradiation, indicating excellent photocatalytic activity.     

Hydrothermal Synthesis and Crystal Structures of Cd(II)-Based 1D Coordination Polymer and Mn(II) Coordination Complex with Mixed N- and O-donor Ligands: [Cd2(4-4′-bpy)2(pa)4]n·0.25(H2O) and [Mn(4-4′-bpy)2(pa)(H2O)3]ClO4·2(H2O)

Two new complexes, [Cd₂(4-4′-bpy)₂(pa)₄] _n ·0.25H₂O (1) (pa = phenylacetate), and [Mn(4-4′-bpy)₂(pa)(H₂O)₃]ClO₄·2H₂O, (2), have been obtained from hydrothermal reaction of Cd(NO₃)₂·4H₂O and Mn(ClO₄)₂·6H₂O with a mixture of the ligands, 2-phenylmalonic acid (2-phmalH₂) and 4-4′-bipyridine (4-4′-bpy). The pa is formed in situ by decarboxylation of phenylmalonic acid. These complexes have been characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis and single-crystal X-Ray diffraction. The Cd(II) center is seven-coordinate and linked via pa ligands to form a binuclear complex in the asymmetric unit of 1. A ladder-like 1D chain of binuclear units is formed by Cd(II)–N coordination bond through 4-4′-bpy ligands. Complex 2 consists of a mononuclear manganese center based on a distorted octahedral geometry and exhibits a supramolecular structure containing hydrogen bonds and extensive π···π and C–H···π interactions.     

Solvent control on the structural versatility and properties of manganese(II) complexes surrounded by the flexible hinge-like ligand

Four different types of polynuclear manganese(II) compounds with bhnq^2? bridges were obtained from the reaction of Mn(CH₃COO)₂·4H₂O with the flexible hinge-like ligand H₂bhnq (H₂bhnq = 2,2′-bi(3-hydroxy-1,4-naphthoquinone)) by controlling the reaction solvent: [Mn₃(bhnq)₃(H₂O)₂]·10.5H₂O (1), [Mn₂(bhnq)₂(DMSO)₄]·2DMSO·CHCl₃ (2), {[Mn(bhnq)(H₂O)₂]·2H₂O}_n (3), and {[Mn(bhnq)(DMF)₂]}_n (4). All complexes are neutral with the same Mn/bhnq 1:1 formulation ratio. Compounds 1 and 2 are discrete systems, while compounds 3 and 4 are one-dimensional ones. All compounds were characterized by X-ray diffraction and show different coordination modes for the bhnq^2? ligand.     

Synthesis, Structures and Luminescent Properties of Two New Cd(II) Coordination Polymers Based on V-Shaped 3,3′,4,4′-Oxidiphthalic Acid

Two new Cd(II) coordination polymers, namely [Cd₂(H₂OA)₂(μ₂-H₂O)(H₂O)₆] _n ·3nH₂O (1) and [Cd₂(H₂OA)(phen)₂] _n ·nH₂O (2) (H₄OA = 3,3′,4,4′-oxidiphthalic acid, phen = 1,10-phenanthroline) have been synthesized by combining H₄OA or H₄OA and phen with Cd(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 features a hydrogen-bond directed two-dimensional (2D) layered structure constructed from alternating left- and right-handed double strand helical chains, 2 represents a one-dimensional (1D) chain structure with the phen molecules dangling on it, which is further extended into a three-dimensional (3D) supramolecular framework through strong face-to-face π···π interactions. In addition, luminescent properties of these two compounds were also investigated in the solid state at room temperature.     

Hydrothermal Syntheses and Crystal Structures of Three Zn(II) Coordination Compounds Constructed with 3,5-Pyrazoledicarboxylic Acid

Three novel metal–organic coordination compounds, [Zn(Hdcp)(H₂O)₄]·1.5H₂O (1), [Zn(Hdcp)(H₂O)₂]_∞ (2) and [Zn₃(dcp)₂(H₂O)₅]_∞ (3) with the ligand 3,5-pyrazoledicarboxylic acid were prepared by the hydrothermal method. The complexes were structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Compound 1 is a mononuclear molecule that is linked into a 3D supramolecular framework via N–H···O and O–H···O hydrogen bonds. In 2, two types of carboxylic bridges were found between Zn^II ions to form a 1D double-chain. The 1D chains were further construct into a 3D structure by hydrogen bonds. Trinuclear 3 consists of 1D bi-infinite parallelogram chains of [Zn₃(dcp)₂(H₂O)₃] trimers. In the basic trinuclear unit a further bridging mode of the ligand is seen where two dcp^3? ligands chelate three Zn^II ions by utilizing five donors of the dcp^3? ligand. The photoluminescent properties of 1, 2 and 3 were investigated.