A series of novel Zn(Ⅱ) and Mn(Ⅱ) metal-organic frameworks constructed by 2,4-bis-oxyacetate-benzoic acid: syntheses,structures and photoluminescence

A new carboxylic acid ligand, 2,4-bis-oxyacetate-benzoic acid(H3BOABA), was designed and introduced to construct novel metal-organic framework materials. [Zn Na(BOABA)(phen)(H2O)]·H2O(1), Zn Na(BOABA)(2), Mn3(BOABA)2(phen)2(3), [Mn2(BOABA)(OH)]·(H2O)2(4)(CCDC: 885138, 885137, 894225, 883094) were hydrothermally synthesized and characterized by elemental analysis, IR spectra and thermal gravimetric analyses. Crystal structures of the complexes were determined by single crystal X-ray diffraction method. Complex 1 is a one dimensional double edges non-interpenetrated framework decorated by the phen ligands on the surface. Complex 2 is an unique three dimensional open framework, consisting of Zn(II) and Na(I). Complex 3 is an unique double edges one dimensional MOF containing a [Mn3(BOABA)2(phen)2]n non-interpenetrated structure. Complex 4 is a two dimensional plane structure containing two Mn atoms in the same coordination environment. The interaction between four complexes and DNA were studied by Et Br fluorescence probe. Meanwhile, photoluminescence studies revealed that these four complexes display strong fluorescent emission bands in the solid state at room temperature.     

Syntheses,structures and luminescence of two copper(I)–dppm complexes,dppm = bis(diphenylphosphino) methane

Two copper(I)–dppm complexes, [Cu₂(dppm)₂(NMP)₂](ClO₄)₂ (1) (NMP?=?2-(4-dimethylaminophenyl)imidazo(4,5-f)(1,10)phenanthroline, dppm?=?bis(diphenylphosphino) methane) and [Cu₂(dppm)₂(phen-NO₂)₂](ClO₄)₂ (2) (phen-NO₂?=?5-nitro-1,10-phenanthroline), were synthesized and their crystal structures were determined by X-ray diffraction. The different ligands chelated to copper(I) give distinct luminescent properties. Complex 1 shows a broad emission (λ _max?=?523?nm) in the visible region with short lifetime (0.33?ns), while complex 2 has a large red shift (λ _max?=?634?nm) and has longer emission lifetime (0.23?µs) compared with complex 1. DFT calculations indicate that emission of 1 and 2 originate from singlet ILCT excited states and triplet MLCT excited states, respectively.     

Syntheses,structures, and properties of two metal-organic frameworks comprising bpdc (2,2′-biphenyldicarboxylate) and bipb (2,2′-bis(imidazol-1-ylmethyl)-biphenyl)

Two new coordination polymers, [Cd(bpdc)(bibp)(H₂O)₂] _n (1) and [Zn(bpdc)(bibp)] _n (2), have been hydrothermally synthesized from 2,2′-biphenyldicarboxylate (bpdc) and 2,2′-bis(imidazol-1-ylmethyl)-biphenyl (bipb). Polymer 1 features a 1-D tubelike porous chain along the a direction with coordinated water molecules occupying the pores. The double-chain of polymer 2 possesses alternating rectangular rings [(bpdc)₂Zn₂] and [(bibp)₂Zn₂] with Zn as nodes. The polymers exhibit strong fluorescent emissions in the solid state at room temperature and could be significant as photoactive materials.     

Synthesis,crystal structures,and properties of two heterometallic Cu(II)–M(II) (M = Zn,Ni) oxamidato-bridged coordination complexes

Two heterometallic coordination complexes, {[Cu(aeop)Zn(H₂O)₃]₂?·?3H₂O} _n (1) and [Cu(aeop)Ni(H₂O)₄]?·?4H₂O (2) (H₄aeop?=?N-(2-aminoterephthalic acid)-N′-(1,3-propanediamine)oxamidate), have been synthesized and characterized by elemental analyses, IR, UV spectroscopy, thermogravimetric analysis, and X-ray crystal diffraction. Complex 1 features a 1-D chain constructed from neutral tetranuclear units. Complex 2 is a neutral binuclear complex. Through intermolecular hydrogen-bonding interactions, 2 gives a 3-D network structure. The variable temperature magnetic susceptibility measurements (2–300?K) of 2 show a pronounced antiferromagnetic interaction between the copper(II) and nickel(II), and the exchange integral J is equal to ?42.7?cm^?1.     

Two manganese(II) complexes constructed from 2-(3-pyridyl)-imidazo[4,5-f] 1,10-phenanthroline and organic dicarboxylates: syntheses,crystal structures,and luminescence

In this study, two new Mn(II) complexes consisting of a phenanthroline derivative and organic acid ligands, [Mn(3-PIP)(1,3-bdc)] _n (1) and [Mn(3-PIP)₂(1,4-bdc)] _n (2) (3-PIP?=?2-(3-pyridyl)-imidazo[4,5-f]?1,10-phenanthroline, 1,3-H₂bdc?=?benzene-1,3-dicarboxylic acid, 1,4-H₂bdc?=?benzene-1,4-dicarboxylic acid), have been synthesized via hydrothermal reaction and characterized by Fourier transform infrared (FT-IR) spectra, elemental analyses, and single-crystal X-ray diffraction. Complex 1 is a one-dimensional (1-D) twisted double chain bridged by 1,3-bdc. The 3-PIP ligands in a parallel fashion are alternately attached to both sides of the 1-D double chain. Complex 2 exhibits a 1-D zigzag chain, to which pairs of crossed 3-PIP ligands are alternately attached. The two complexes are further extended into three-dimensional (3-D) supramolecular structures by hydrogen-bonding and π–π stacking interactions. The N-donor ligands with an extended π-system play a crucial role in formation and stabilization of the final supramolecular frameworks. Thermal properties of 1 and 2 and fluorescence of 2 are investigated in the solid state.     

Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers constructed from quinolinic acid and nicotinic acid: Synthesis, structures, and magnetic properties

Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers based on two N-heterocyclic carboxylic ligands, {[LnCu(L1)2(L2)(H2O)2]·mH2O}n (Ln = La(1), Nd(2), Gd(3), m = 2 (for 1), 1 (for 2, 3), H2L1 = quinolinic acid, HL2 = nicotinic acid), have been synthesized and characterized. 1 has a two-dimensional (2D) layer structure with a Schlfli symbol of (44.62), while complexes 2 and 3 are isostructural and have three-dimensional (3D) structures with a Schlfli symbol of (3.4.5)2(32.42.52.614.74.83.9)(32.63.7) of 3-nodal net. Magnetic investigations suggest that antiferromagnetic coupling exists between NdIII and CuII in 2, while weak ferromagnetic coupling between GdIII and CuII in 3. The difference of magnetic properties between 2 and 3 has been discussed.     

Crystal structures of two new dinuclear Ag(I) complexes constructed from 4,4′-biphenyldicarboxylic acid and N-containing ligands

The reaction of silver 4,4′-biphenyldicarboxylate with 1,3-diaminopropane (DAP) and 2-amino-5-methylpyridine (AMP) respectively results in the formation of two dinuclear silver(I) complexes: [Ag₂(DAP)₂](BPC)·2H₂O (1) and [Ag₂(BPC)(AMP)₄]·2H₂O (2), where BPC is 4,4′-biphenyldicarboxylate. The complexes are characterized by elemental analysis and X-ray crystallography. Complex 1 crystallizes in the triclinic system, P-1 space group, a = 8.585(2) Å, b = 8.849(2) Å, c = 9.890(3) Å, α = 107.893(3)°, β = 94.139(3)°, γ = 113.202(3)°, V = 640.9(3) ų, Z = 1. Complex 2 crystallizes in the triclinic system, P-1 space group, a = 11.818(3) Å, b = 13.132(4) Å, c = 13.281(4) Å, α = 92.571(4)°, β = 96.425(3)°, γ = 102.142(4)°, V = 1997.5(10) ų, Z = 2. Complex 1 consists of a macrocyclic dinuclear silver(I) dication, a 4,4′-biphenyldicarboxylate anion, and two water molecules of crystallization. Each Ag atom is in a linear coordination. Complex 2 consists of a dinuclear silver(I) complex molecule and two water molecules of crystallization. Each Ag atom is in a T-shaped coordination. The Ag...Ag separations are 5.127(2) Å in 1 and 3.172(2) Å in 2.     

A series of 3d–4f heterometallic MOFs: syntheses,structures, optical,and electrochemical properties

Abstract

A series of heterometallic metal-organic frameworks (MOFs) employing pyridine-2,6-dicarboxylate and 1,10-phenanthroline as ligands have been synthesized hydrothermally. In isostructural compounds 1–3 [Ln(pydc)₃Cu₂(phen)₄]·I·× H₂O (Ln?=?La (1), Nd (2), Dy (3); x?=?6, 5, 5), the metalloligand [Ln(pydc)₃] assembles with [Cu(phen)₂] units to construct a dodecanuclear cluster via Cu–O bonds and π–π interactions. The clusters are further stacked into three-dimensional supramolecular frameworks with nano-sized cavities. In [La(Hpydc)(pydc)₂Zn(phen)₃]·3H₂O (4), the metalloligand [Ln(Hpydc)(pydc)₂] assembles with [Zn(phen)₃] units to construct a tetranuclear cluster via electrostatic interaction and π–π interaction. This work reveals that the changes of lanthanide metalloligands and the coordination pattern of 3d transition centers would result in significant variation in the final structures. The thermal, optical, and electrochemical properties have been well investigated.     

Zn(II) and Cd(II) metal–organic frameworks (MOFs) constructed from a symmetric triangular semirigid multicarboxylate ligand: Synthesis,structures and luminescent properties

Three transition metal coordination polymers [Zn₂(H₂L)(2,2′-bpy)₂(H₂O)]_n∙2nH₂O (1), [Zn₂(H₂L)(2,2′-bpy)₂]_n (2), and [Cd₂(H₂L)(2,2′- bpy)₂(H₂O)₂]_n∙2nH₂O (3), have been assembled from a semirigid triangular multicarboxylate ligand 3,3′,3″-(1,3,5-phenylenetri(oxy))triphthalic acid (H₆L) with the help of 2,2′-bipyridine (2,2′-bpy) ligand. X-ray single crystal diffraction analysis reveals that complex 1 crystallizes in the space group of Pī and displays a one-dimensional (1D) ladder chain structure constructed from 2,2′-bpy ligand and H₂L ligand, which stacks together in an -ABCABC- motif, featuring a mutually embedded chained structure. In complex 2, the H₂L ligands bridge the adjacent Zn(II) atoms into a complicated ribbon chain along the b axis. There is π–π stacking interaction between the chains, which results in the formation of a 2D supramolecular structure. Complex 3 also exhibits a 1D ladder-like chain. The different molecular structures for complexes 1 and 2 formed from the same H₆L and Zn(NO₃)₂∙6H₂O in different metal-to-ligand ratios in the presence of NaOH, reveals the influence of metal–ligand ratio on the structure of the coordination polymer. In contrast, a series of same reaction using Cd(NO₃)₂∙4H₂O as a starting material instead of Zn(NO₃)₂∙6H₂O only led to the formation of 3, illustrating the fact organic ligands display different coordination preferences at different metal ions. In addition, the thermal and luminescent properties of complexes 1–3 were also investigated.     

Two M(II)-1,5-NDS-dafo supramolecular architectures (M = Cu,Cd): syntheses,structures, and photoluminescence properties

Under hydrothermal conditions, reaction of Cu(II)/Cd(II) salts with 1,5-naphthalenedisulfonate (1,5-NDS) and 4,5-diazafluoren-9-one (dafo) afforded [Cu(dafo)₂(1,5-NDS)]_n (1) and [Cd(dafo)₂(1,5-NDS)]_n (2), respectively. The compounds were characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Both 1 and 2, which are the first M(II)-1,5-NDS-dafo systems, exhibit 3-D supramolecular structures generated by 1-D chains via C–H?O hydrogen bonds and π–π interactions. Solid-state photoluminescence properties of both 1 and 2 were investigated with emission bands at 426–496?nm (λ _ex?=?280, 270?nm for 1 and 2, respectively).     

Synthesis,structures, and properties of lead(II) and cobalt(II) metal-organic frameworks based on a flexible benzophenone-2,4′-dicarboxylic acid (H2bpdc)

Two new coordination polymers, [Pb(bpdc)] _n (1) and [Co(bpdc)(phen)] _n (2) [H₂bpdc?=?benzophenone-2,4′-dicarboxylic acid, phen?=?1,10-phenanthroline], have been synthesized and structurally characterized. Hydrogen bonding and π?···?π stacking extend 1 and 2 into 3-D supramolecular architectures, where 1 exhibits a 3-D framework with 1-D hairpin-like helicates based on Pb–O covalent bonds and 2 displays a 3-D network with 1-D zipper-like chains based on Co–O and Co–N covalent bonds. The FT-IR spectra, PXRD and TG analyses are discussed for 1 and 2. Fluorescence spectra and luminescent lifetime are studied for 1.     

Synthesis,structures, thermal behaviour,luminescence and magnetic properties of lanthanide complexes constructed from 2,6-dimethylbenzoic acid and 5,5′-dimethyl-2,2′-bipyridine

Six new lanthanide complexes, with the formula [La(2,6-DMBA)₃(5,5′-DM-2,2′-bipy)(H₂O)]₂ (1) and [Ln(2,6-DMBA)₃(5,5′-DM-2,2′-bipy)]₂ (Ln = Tb(2), Dy(3), Ho(4), Pr(5), Nd(6)) (2,6-DMBA = 2,6-dimethylbenzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′-bipyridine) have been successfully synthesized and characterized. These title complexes have three different structural types. The structure of complex 1(type I) contains coordination water molecules, and the coordination number is 8. The coordination numbers of complexes 2–4 and 5–6 are 8 and 9, showing a distorted square antiprism geometry and distorted monocapped square anti-prismatic geometry, respectively. However they have the same general formula and they can be all assembled into the same 1D, 2D supramolecular structures via the C-H···O hydrogen bonding interactions, which is interesting in previous lanthanide complexes. The complexes were analyzed by TG-DSC/FTIR. In addition, the visible light luminescence experiments of Tb (III) complex was carried out, and the characteristic luminescence behavior of strong green color was shown. And the fluorescence lifetime and intrinsic quantum yield were calculated. The magnetic properties of complexes 2–4 were also studied, and the results showed that complex 3 and complexes 2, 4 have ferromagnetic interactions and antiferromagnetic interactions, respectively.     

Four 3d–4f heteromultinuclear zinc(II)–lanthanide(III) complexes constructed from a distinct hexadentate N2O2-type ligand: syntheses,structures and luminescence properties

Four 3d–4f heteronuclear complexes, [(ZnL)₂La(OAc)₂]·ClO₄·2CHCl₃ (1), [(ZnL)₂La(OAc)₂]·CF₃SO₃·H₂O (2), [ZnNd(L)(Py)(NO₃)₃] (3), and [ZnGd(L)(OAc)(NO₃)₂] (4) (Py = pyridine; H₂L = 6,6′-dimethoxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol), have been prepared by one-pot reaction of H₂L with zinc(II) acetate, lanthanide(III) ions and Py. Although the heterobinuclear complexes 1–4 are prepared in the same reaction condition, the Py does not coordinate to Zn(II) of 1, 2, and 4. Instead, the bridging μ-acetato ligand is present. The coordination of the Py in 3 leads to smaller distortion of square pyramidal coordination site of Zn(II), the higher coplanarity between the planes of ZnO(phenoxo)₂ and LnO(phenoxo)₂, and the longer Zn?Ln distance compared with 4. The luminescence properties of 1–4 have been discussed. The ligand (L^2?) can sensitize NIR luminescence of Nd(III) ions.     

A series of heterobimetallic Ni(II)–Ln(III) (Ln = La,Ce, Pr and Nd) coordination polymers derived from 3-EtOsalamo and dicarboxylates: syntheses,crystal structures and fluorescence properties

Transition Metal Chemistry - Four coordination polymers ∞2 [Ni(DMF)(L)Ln(bdc)1.5] (Ln?=?La (1) and Nd (4)) and ∞2 [Ni2(DMF)2(L)2Ln2(bdc)3]·CH3OH (Ln?=?Ce...     

First-principles calculations on the structures,magnetic, and electronic properties of the (Fe2N)m (m = 1–4) and (Fe3N)n (n = 1–3) clusters

The structures, magnetic, and electronic properties of the ground-state (Fe₂N)_m (m?=?1–4) and (Fe₃N)_n (n?=?1–3) clusters have been investigated by using first-principles. The structure of the (Fe₂N)_m and (Fe₃N)_n clusters is a compromise that the N atoms approach more Fe atoms and the N atoms repel each other. The structural stabilities of the (Fe₂N)_m and (Fe₃N)_n clusters increase with the increasing of the N ratio except for the Fe₆N₃ clusters. The (Fe₂N)_m (m?=?1–4) and Fe₉N₃ clusters exhibit more kinetic stabilities than pure iron clusters. The N substitution can decrease the average spin densities of small iron clusters except for the Fe₆N₂ and Fe₈N₄ clusters. The Fe–N bonds exhibit certain covalent bond characteristics.

     

Three metal-organic polymers assembled from Cd(II)–fluconazole: Syntheses,crystal structures,and characterization

Three new complexes [Cd(Hflu)₂(NO₃)](NO₃) 1, [Cd(H₂O)(Hflu)₂(Hmalo)](NO₃)?2(H₂O) 2, and [Cd(H₂O)(Hflu)₂(Hfum)](NO₃)?2(H₂O) 3 (Hflu = [2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol], H2fum = fumaric acid, H₂malo = malonate acid) are synthesized by a solution diffusion method and characterized by single crystal X-ray diffraction methods, elemental analyses, IR spectroscopy as well as thermal analyses. In compound 1, Cd(II) cations are bridged by fluconazole ligands to form 2D Cd?Hflu layers, and these layers are further connected by C–H???F hydrogen bonds to form a complicated 3D structure with the topology of (4?6?8)(4?64?84?10)(6?3). Compounds 2 and 3 are isostructural, and in them the Cd(II) cations are bridged by fluconazole ligands to form a 2D network, which is connected by C–H???O hydrogen bonds to form a complicated 3D (3,4)-connected framework with the topology of (4?8²)(4?8⁵).     

Synthesis,X-ray crystal structures,and luminescent properties of two coordination polymers constructed from transition metal complexes of mixed flexible–rigid ligands

Two new coordination polymers [Ni(C₆H₁₀O₄)(C₁₀H₈N₂)] _n (1) and [Zn₃(C₆H₁₀O₄)₃(C₁₂N₂H₈)₂] _n (2) have been synthesized under hydrothermal conditions. Complex (1) exhibits an interesting three-dimensional interpenetrating network, whereas complex (2) has a two-dimensional network. The IR and TG properties of these two complexes are studied. Furthermore, complex (2) exhibits photoluminescence. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Four tri-spin lanthanide–nitronyl nitroxide (LnIII = GdIII,DyIII, ErIII,and HoIII) complexes: syntheses,structures, and magnetic properties

Four radical–Ln(III)–radical complexes, [Ln(hfac)₃(NITPhSCH₃)₂] (Ln?=?Gd (1), Dy (2), Er (3), Ho (4); hfac?=?hexafluoroacetylacetonate; NITPhSCH₃?=?4′-thiomethylphenyl-4,4,5,5tetramethyl-imidazoline-1-oxyl-3-oxide), have been synthesized, and structurally and magnetically characterized. The X-ray crystal structures show that the structures of the four complexes are similar, consisting of isolated molecules in which Ln(III) ions are coordinated by six oxygen atoms from three hfac and two oxygen atoms from nitronyl radicals. The temperature dependencies of magnetic susceptibilities for the four complexes show that in the Gd(III) complex, ferromagnetic interactions between Gd(III)–radical and antiferromagnetic interactions between the radicals coexist with J _Rad–Gd?=?1.09?cm^?1, J _Rad–Rad?=??1.85?cm^?1.