Synthesis, crystal structure, and magnetic properties of two 3d-4f heterometallic coordination polymers

Two new 4f-3d heterometallic coordination polymers, [Gd₂^IIICo^II(pydc)₃(ox)(H₂O)₄)·2H₂O] (1) and [Dy^IIICu^II(pydc)₂(ox)_1/2(H₂O)₂·H₂O] (2) (pydc = pyridine-2,5-dicarboxylate anion, ox = oxalate dianion) were successfully synthesized under hydrothermal condition. Structure and magnetism of the two coordination polymers were characterized by single crystal X-ray diffraction and Quantum Design (MPMS) SQUID magnetometer. In both compounds, metal centers were connected by double ligand bridges. In 1 the gadolinium ions were linked in sheets by OCO ligand bridges and these sheets were connected by separated cobalt coordination spheres to generate the overall 2-D structure. In 2 the dysprosium centers were constructed into one dimensional chain by OCO bridges from pydc ligand bridges and these chains were linked by oxalate bridges to form sheets and different sheets were connected by copper coordination planes. The copper centers in 2 were linked in chain by elongated OCO brides and the chains were connected by hydrogen bond to generate 3-D structure. Magnetic properties of the two complexes were investigated by variable temperature magnetic susceptibility. The magnetic data suggest that overall antiferromagnetic interactions are present in the two compounds.     

A series of two‐dimensional lanthanide coordination polymers: synthesis,structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents

A series of two‐dimensional (2D) coordination polymers (CPs), namely poly[[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)digadolinium(III)] N,N‐dimethylacetamide monosolvate], {[Gd₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]·C₄H₉NO}_n ( CP1 ), poly[[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)didysprosium(III)] N,N‐dimethylacetamide monosolvate], {[Dy₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]·C₄H₉NO}_n ( CP2 ), poly[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)dineodymium(III)], [Nd₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]_n ( CP3 ), poly[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)disamarium(III)], [Sm₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]_n ( CP4 ), has been synthesized from rigid biphenyl‐3,3′,5,5′‐tetracarboxylic acid under solvothermal conditions. Their structures have been determined by single‐crystal X‐ray diffraction analyses, elemental analyses, IR spectra, powder X‐ray diffraction and thermogravimetric analyses, and CP1 – CP4 crystallize in the monoclinic space group P2₁/n. CP1 – CP4 are isomorphous and feature similar 2D double layers, which are further extended via interlayer hydrogen‐bonding interactions into a three‐dimensional (3D) supramolecular structure. Hydrogen‐bonding interactions between N,N‐dimethylacetamide molecules and carboxylate O atoms strengthen the packing of the layers. The organic ligands interconnect with metal ions to generate 2D layered structures with a (4,4)‐connected net having {4⁴.6²} topology. CP1 has been investigated for its magnetic properties and magnetic susceptibility measurements were carried out in the range 2.0–300 K. The results of the magnetic measurements show weak antiferromagnetic coupling between the Gd^III ions in CP1 . Moreover, the strong luminescence of CP2 and CP4 can be selectively quenched by the Fe³⁺ ion and toxic solvents (e.g. acetone).     

Hydrothermal syntheses,crystal structures,and photocatalytic properties of two Co(II) complexes with the flexible citraconic acid

Two Co(II) coordination polymers, [Co(ca)(bib)]_n ( I ) and {[Co(ca)(bibp)_1.5]·1.5H₂O} _n ( II ) (H₂ca = citraconic acid, bib = 1,4-bis(1-imidazoly)benzene, bibp = 1,4-bis-[4-(imidazol-1-yl)benzyl]piperazine), were prepared by hydrothermal method and measured structurally by single-crystal X-ray diffraction, infrared spectroscopy, and elemental analysis. Complex I shows a 2D layer structure containing Co-carboxylate chains. Complex II displays a 3D metal–organic framework composed of the binuclear [Co₂(CO₂)₂]²⁺ cluster nodes through ca²⁻ and bibp as linkers with (4¹²·6³) topology. Complexes I and II have high thermal stabilities because their frameworks maintain good integrity before 340°C and 265°C, respectively. Both complexes show well photocatalytic activities for methylene blue degradation under UV irradiation in the presence of H₂O₂, which may be used as potential materials for photocatalytic dyes degradation.     

Synthesis,Magnetism, and Thermostability of a Series of Two‐Dimensional Lanthanide–Nickel Heterometallic Coordination Polymers

A series of Ln–Ni heterometallic coordination polymers, {[Ln₂Ni(MIDA)₄(H₂O)₆](H₂O)₄} (Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 ), and Nd ( 4 ); H₂MIDA = N‐methyl‐iminodiacetic acid), were obtained under hydrothermal conditions. Single crystal X‐ray diffraction revealed that they feature two‐dimensional isomorphic frameworks, which could be viewed as the construction by one‐dimensional {Ln}_n chain connecting by bridges of [Ni(MIDA)₂]². The magnetic measurements reveal that compounds 2 – 4 exhibit antiferromagnetic properties. TGA results indicate compounds 1 and 4 have good thermostability with the critical temperature of 375 °C.     

Toward templated metal-organic frameworks: synthesis, structures, thermal properties, and luminescence of three novel lanthanide-adipate frameworks

Three novel praseodymium-adipate frameworks were synthesized hydrothermally. GWMOF-3 ([Pr(2)(adipic acid)(3)(H(2)O)(4)].adipic acid.4H(2)O) and GWMOF-6 ([Pr(2)(adipic acid)(3)(H(2)O)(2)].4,4'-dipyridyl) formed three-dimensional structures, whereas GWMOF-4 ([Pr(2)(adipic acid)(3)(H(2)O)(2)].H(2)O) produced a more dense, two-dimensional topology. Single-crystal X-ray and powder diffraction, IR spectroscopy, fluorescence spectroscopy, thermogravimetric analysis, and elemental analysis were employed to characterize all samples. GWMOF-6 represents an innovative step forward in metal-organic framework synthesis where a neutral molecular species not used in the construction of the framework is utilized as a structure-directing agent, or template. Furthermore, this template molecule (4,4'-dipyridyl) is shown to sensitize the fluorescence of lanthanide metal centers in a europium analogue of GWMOF-6.     

Lanthanide-organic frameworks constructed from multi-functional ligands: Syntheses, structures, near-infrared and visible photoluminescence properties

A series of multi-functional ligands supported lanthanide-organic frameworks, formulated as [Ln(HL₁)(H₂L₂)_0.5(H₄L₂)_0.5(H₂O)]·(H₂O)_1.5·{Ln=La (1), Pr (2), Nd (3), Sm (4), Eu (5); H₃L₁=5-Sulfosaclicylic acid; H₄L₂=N,N′-piperazine (bis-methylene phosphonic acid)}, have been synthesized by hydrothermal reactions. Single crystal X-ray diffractions and powder XRD patterns confirm they are isostructural. They feature 3D framework structures based on extension of a “zigzag” inorganic chain by organic linkers. Moreover, the photoluminescence properties of 5 and 3 have been investigated, and they show strong solid-state emissions in the visible and near-infrared (IR) regions at room temperature.     

Hydrothermal synthesis,crystal structures,and photoluminescent properties of two cadmium(II) coordination polymers derived from dicarboxylates and N-donor ligands

Two metal coordination polymers, [Cd(ipa)(L₁)(H₂O)]_n (1) and [Cd(ipa)(L₂)]_n (2) [H₂ipa?=?isophthalic acid, L₁?=?3,5-bis(imidazole-1-yl)pyridine and L₂?=?3,5-bis(benzoimidazo-1-ly)pyridine], have been synthesized and structurally characterized by IR, elemental analysis, XRD, and X-ray single-crystal diffraction. Complex 1 shows a twofold cds topological net and 2 features a 3-D pcu topological net. Luminescent properties of 1 and 2 were investigated in the solid state at room temperature.     

Two Zn(II) coordination polymers constructed by a new tricarboxylate and different N-containing ligands: synthesis,crystal structures,and selective luminescence sensing for Fe3+ in aqueous solution

Two Zn(II) coordination polymers, {[Zn₃(L)₂(bipy)₂(H₂O)₄}_n (1) and {[Zn(HL)(4,4′-bibp)}_n (2), were obtained from Zn(II) nitrate, a tricarboxylate ligand (H₃L) and different N-containing ligands with hydrothermal conditions, where H₃L = 4-((6-carboxynaphthalen-2-yl)oxy)phthalic acid, bipy = 4,4′-bipyridine, and 4,4′-bibp = 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl. Single-crystal X-ray analysis reveals that 1 has a 2-D layer framework formed by L^3? and bipy and 2 has an infinite 1-D structure with Zn₂ units built by 4,4′-bibp ligands. The phase purity, IR spectra, thermal stabilities, and fluorescence properties in the solid state of 1 and 2 were investigated. Moreover, 1 and 2 were chosen as fluorescent probes to sense different metal ions, showing selective response to Fe³⁺ ion through luminescence quenching. The possible sensing mechanism to Fe³⁺ ion is also discussed.     

A family of three-dimensional 3d-4f and 4d-4f heterometallic coordination polymers based on mixed isonicotinate and 2-sulfobenzoate ligands: syntheses, structures and photoluminescent properties

Hydrothermal reactions of isonicotinic acid (Hina), 2-sulfobenzoic acid (H(2)sba), d-block metal salts and lanthanide oxides/hydroxides yielded 17 three-dimensional (3D) 3d-4f and 4d-4f heterometallic coordination polymers (HCPs). They are formulated as [LaAg(sba)(ina)(2)](n) (1), [Ln(2)Ag(2)(sba)(2)(ina)(4)(H(2)O)(2)](n) [Ln = Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10)] and [Ln(2)Cu(2)(sba)(2)(ina)(4)(H(2)O)(2)](n) [Ln = La (11), Pr (12), Nd (13), Sm (14), Eu (15), Gd (16), Tb (17)]. Their structures were characterized by single crystal X-ray diffraction, powder X-ray diffraction (XRD), infrared (IR) spectroscopy, elemental analysis (EA), and thermogravimetric analysis (TGA). It reveals that they represent two structural types of 3D HCPs. Furthermore, the investigations of their solid-state photoluminescent (PL) property demonstrate the extraordinary emission behaviors. HCP 1(La-Ag) exhibits tunable blue-to-green PL emissions by variation of excitation light. HCPs 6(Gd-Ag), 11(La-Cu), 12(Pr-Cu) and 16(Gd-Cu) show d(10)-metal-based ligand-to-metal charge transfer (LMCT) or metal-to-ligand charge transfer (MLCT) emissions. HCPs 3(Nd-Ag), 4(Sm-Ag), 5(Eu-Ag), 7(Tb-Ag), 8(Dy-Ag), 13(Nd-Cu), 14(Sm-Cu), 15(Eu-Cu) and 17(Tb-Cu) display characteristic PL emissions of the corresponding Ln(III) ions, while both d(10)-metal-based and 4f-metal-centered emissions are observed in the emission spectra of 4(Sm-Ag), 8(Dy-Ag), 14(Sm-Cu) and 17(Tb-Cu).     

UO22+-polycarboxylate heterometallic complexes: structure,spectra, and photocatalytic properties

[Cu₂(UO₂)₄(suc)₄(pac)₄] (1), [(Cu(H₂O)₂)(4,4′-bipy)₂][(UO₂)₂(H₂O)₂(Hca)₂]·3H₂O (2), and [(Cu(H₂O)₂)(UO₂)(bta)]·4H₂O (3) were synthesized by the reaction of succinic acid and 3-pyridinecarboxylic acid, citric acid and 4,4′-bipyridine, or 1,2,4,5-benzenetetracarboxylic acid ligands with Cu(NO₃)₂·3H₂O and UO₂(CH₃COO)₂·2H₂O. The complexes were characterized by IR and UV–vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and photoluminescence spectroscopy. Photocatalytic activities of the complexes were also investigated.     

Structural variation from linear,layer to 3D framework: Syntheses,structures and luminescence

Self‐assembly of Zn (II) or Cd (II) nitrates, flexible bis (pyridyl)‐diamine, as well as arenesulfonic acids, leads to the formation of ten coordination polymers, namely, [Zn(L1)(H₂O)₃]·2(p‐TS)·2H₂O ( 1 ), [Zn(L1)(H₂O)₂]·2(p‐TS)·2H₂O ( 2 ), [Zn(L1)₂(p‐TS)₂] ( 3 ), [Zn(H₂L1)(H₂O)₄]·2(1,5‐NDS)·2H₂O ( 4 ), [Zn(H₂L2)(H₂O)₄]·2(1,5‐NDS)·4MeOH ( 5 ), [Cd(L1)(p‐TS)(NO₃)]·H₂O ( 6 ), [Cd(L1)(1,5 ‐NDS)_0.5(H₂O)]·0.5(1,5‐NDS)·H₂O ( 7 ), [Cd(L2)(H₂O)₂]·(p‐TS)·(NO₃)·3H₂O ( 8 ), [Cd(L2)(1,5‐NDS)] ( 9 ) and [Cd(L2)(1,5‐NDS)]·MeOH ( 10 ) (L1 = N,N′‐bis (pyridin‐4‐ylmethyl) ethane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethy l)ethane‐1,2‐diamine, p‐HTS = p‐toluenesulfonic acid, 1,5‐H₂NDS = 1,5‐naphthalene disulfonic acid), which have been characterized by elemental analysis, IR, TG, PL, powder and single‐crystal X‐ray diffraction. Complexes 1 , 4 , 5 and 6 present linear or zigzag chain structures accomplished by the interconnection of adjacent M (II) cations through L1 ligands or protonated H₂L1²⁺/H₂L2²⁺ cations, while complexes 2 , 3 and 8 show similar (4,4) layer motifs constructed from the connection of M (II) cations through L1 and L2. The same coordination modes of L1 and L2 in complexes 7 and 9 join adjacent Cd (II) cations to form double chain structures, which are further connected by bis‐monodentate 1,5‐NDS^2? dianions into different (6,3) and (4,4) layer motifs. The L2 molecules in complex 10 join adjacent Cd (II) cations together with 1,5‐NDS^2? dianions to form 3D network with hxl topology. Therefore, the diverse coordination modes of the bis (pyridyl) ligand with chelating spacer and the feature of different arenesulfonate anions can effectively influence the architectures of these complexes. Luminescent investigation reveals that the emission maximum of these complexes varies from 374 to 448 nm in the solid state at room temperature, in which complexes 4 , 5 , 7 , 9 and 10 show average luminescence lifetimes from 7.20 to 14.82 ns. Moreover, photocatalytic properties of complexes 7–10 towards Methylene blue under Xe lamp irradiation are also discussed.     

Three-dimensional 3d-4f heterometallic coordination polymers: synthesis, structures, and magnetic properties

Three new 3d-4f heterometallic coordination polymers, [Ln(2)(H(2)O)(4)M(2)(H(2)O)(2)(QA)(5)].nH(2)O (H(2)QA = quinolinic acid; Ln = Gd, M = Ni, n = 7 (1); Ln = Gd, M = Co, n = 6.5 (2); Ln = Dy, M = Co, n = 6.5 (3)), have been synthesized through hydrothermal pretreatment and cooling-down crystallization. These compounds possess the isostructural 3D frameworks with 1D chairlike channels along the c axis, which are occupied by noncoordinating water molecules. Crystal data: for 1, C(35)H(41)Gd(2)Ni(2)N(5)O(33), orthorhombic, space group Pna2(1), with a = 28.567(6) A, b = 14.498(3) A, c = 12.250(2) A, and Z = 4; for 2, C(35)H(40)Gd(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.843(3) A, b = 14.4325(13) A, c = 12.2275(9) A, and Z = 4; for 3, C(35)H(40)Dy(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.8471(14) A, b = 14.4534(10) A, c = 12.2520(7) A, and Z = 4. The magnetic behaviors for the three compounds have been investigated.     

Two 3d‐4f Heterometallic Coordination Polymers of Macrocyclic Oxamide with Benzotriazole‐5‐carboxylate Co‐ligand: Syntheses,Crystal Structures and Magnetic Properties

Two heterometallic 3d–4f coordination polymers, [Gd(CuL)₂(Hbtca)(btca)(H₂O)] · 2H₂O ( 1 ) and [Er(CuL)₂(Hbtca)(btca)(H₂O)] · H₂O · CH₃OH ( 2 ) (CuL, H₂L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien; H₂btca = benzotriazole‐5‐carboxylic acid) were synthesized by solvothermal methods and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 exhibit a double‐strand meso‐helical chain structures formed by [Ln^IIICu^II₂] (Ln^III = Gd, Er) units by oxamide and benzotriazole‐5‐carboxylate bridges. They are isomorphic except that one free water molecule of 1 is replaced by a methanol molecule. All 1D chains are further interlinked by hydrogen bonds resulting in a 3D supramolecular architecture. The magnetic properties of the compound 1 and 2 are also discussed.     

Silver-based coordination complexes of carboxylate ligands: crystal structures,luminescence and photocatalytic properties

The complexes [Ag₄(dpe)₄]·(btec) (1) and [Ag₄(bpy)₄]·(btec)·12H₂O (2) (dpe = 1,2-di(4-pyridyl)ethylene, bpy = 4,4′-bipyridine, H₄btec = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized in aqueous alcohol/ammonia by slow evaporation at room temperature and characterized by elemental analysis, single-crystal X-ray diffraction, FTIR, UV–Vis and luminescence spectroscopies. Both complexes are composed of 1D infinite cationic [Ag/dpe(bpy)] _n ⁿ⁺ chains and discrete btec^4? anions. Their three-dimensional supramolecular structures are built up of cationic sheets formed from [Ag/dpe(bpy)] _n ⁿ⁺ units via weak Ag…Ag and Ag…N interactions, plus anionic btec^4? sheets featuring electrostatic, π–π and hydrogen bonding interactions. Both complexes exhibited photocatalytic activity for the decomposition of methyl orange under UV light irradiation.     

Three-dimensional 3d-4f polymers containing heterometallic rings: syntheses, structures, and magnetic properties

Two novel three-dimensional (3D) 3d-4f mixed complexes [Ln(H(2)O)(4)][Ni(2)TTHA(SCN)(2)].H(3)O+ [Ln = Pr (1), Ce (2); H(6)TTHA = triethylenetetraaminehexaacetic acid], based on the building blocks of [Ni(2)TTHA(SCN)(2)](4-), were synthesized and characterized by X-ray crystal diffraction and magnetic properties. The single-crystal structures show that these complexes form a 3D framework, comprised of an unusual infinite one-dimensional chain based on heterometallic Ln2Ni2 rings. The temperature-dependent magnetic susceptibilities were analyzed by an approximate model, leading to g = 2.06. Delta = 2.83, zJ' = -0.6 cm-1 for complex 1 and g = 2.07, Delta = 1.00, zJ' = -0.5 cm(-1) for complex 2.     

Tetrametallic macrocyclic frameworks constructed from ferrocenedicarboxylato and 2,2-bipyridine: synthesis, molecular structures and characteristics

Four novel tetranuclear macrocyclic compounds [Cd₂(η²-O₂CFcCO₂)₂(2,2^′-bpy)₂(H₂O)₂] · 2H₂O (1), [Zn₂(η²-O₂CFcCO₂)₂(2,2^′-bpy)₂(H₂O)₂] · CH₃OH · H₂O (2), [Co₂(O₂CFcCO₂)₂(2,2^′-bpy)₂(μ₂-OH₂)₂] · CH₃OH · 2H₂O (3), and [Ni₂(O₂CFcCO₂)₂(2,2^′-bpy)₂(μ₂-OH₂)₂] · CH₃OH · 2H₂O (Fc=(η⁵-C₅H₄)Fe(η⁵-C₅H₄) (4) have been synthesized and structurally characterized by single crystal diffraction. The magnetic behaviors for compounds (3) and (4) are studied in the temperature range of 5.0-300 K. The results show that the antiferromagnetic coupling of Co^II-Co^II pairs occurs in (3), and unusual global ferromagnetic coupling between nickel (II) ions exists in (4). The solution-state differential pulse voltammetries of compounds (1)-(4) all show two peaks with large separations (ΔE) that indicate strong interactions between two ferrocene moieties. Their fluorescent and thermal properties were also investigated.     

The silica-like extended polymorphism of cobalt(II) imidazolate three-dimensional frameworks: X-ray single-crystal structures and magnetic properties

Five polymorphous frameworks of cobalt(II) imidazolates (1-5) have been prepared by solvatothermal syntheses. Of these, compound 3 has already been synthesized in a gas-phase reaction by Seel et al. in 1969 and structurally characterized by Sturm et al. in 1975. The new synthetic strategy affords four polymorphous frameworks of cobalt(II) imidazolates (1, 2, 4, 5) of crystalline substances, of which the compound 4 (a = b = 23.450(3), c = 12.460(3) A, tetragonal, I4(1)cd, Z = 16) is an isomorphous compound of [Zn(im)(2)]( infinity ), which was also synthesized in a gas-phase reaction in 1980. The frameworks of compounds 1 and 2 are porous and isostructural; they have the same framework topology that represents a novel uninodal (6,4)-net: 1: a = 18.513(4), b = 24.368(5), c = 9.2940(19) A, orthorhombic, Fdd2, Z = 16; 2: a = 17.635(4), b = 27.706(6), c = 9.0810(18) A, orthorhombic, Fdd2, Z = 16. The framework of compound 5 exhibits a topology of zeolitic structure with the unit-cell parameters: a = 24.3406(8), b = 9.4526(3), c = 24.8470(8) A, beta = 91.977(1) degrees, monoclinic, P2(1)/n, Z = 4. All polymorphous frameworks of cobalt(II) imidazolates reflect the structural features of silica (SiO(2)) and also exhibit different magnetic behaviors, although the imidazolates transmit the antiferromagnetic coupling between the cobalt(II) ions in all cases. However, the uncompensated antiferromagnetic couplings arise from spin-canting are sensitive to the structures: compound 1 is an antiferromagnet with T(N) = 13.11 K; compounds 2-4 are weak ferromagnets (canted antiferromagnets): 2 shows a very weak ferromagnetism below 15 K, 3 exhibits a relatively strong ferromagnetism below 11.5 K and a coercive field (H(C)) of 1800 Oe at 1.8 K, and 4 displays the strongest ferromagnetism of the three cobalt imidazolates and demonstrates a T(C) of 15.5 K with a coercive field, H(C), of 7300 Oe at 1.8 K. However, compound 5 seems to be a hidden canted antiferromagnet with a magnetic ordering temperature of 10.6 K.     

Syntheses, structures, and magnetic properties of new rare earth coordination polymers constructed by 1,3,5-benzenetriacetic acid

Three new coordination polymers with formula [Gd(bta)(H₂O)·1.39H₂O] _n (1), [Dy(bta)(H₂O)·1.35H₂O] _n (2) and [Y(bta)(H₂O)₂·0.5H₂O] _n (3) were synthesized by using corresponding rare earth nitrates and 1,3,5-benzenetriacetic acid (H₃bta) under hydrothermal/solvothermal reaction conditions, and characterized by single-crystal X-ray diffraction. In these complexes, the carboxylate groups of bta³⁻ adopt different coordination modes, namely one carboxylate group adopts μ₂-η¹:η¹-bridging and each of the other two carboxylate groups adopts μ₂-η²:η¹-bridging coordination modes in 1 and 2, and one carboxylate group adopts a μ₂-η²:η¹-bridging coordination mode and each of the other two carboxylate groups adopts a μ₂-η¹:η¹-bridging mode for the major component and one carboxylate group adopts a μ₂-η²:η¹-bridging coordination mode, one has a μ₂-η¹:η¹-bridging mode and the third has a monodentate mode for the minor component in 3. The magnetic properties of the complexes 1 and 2 were investigated in the temperature range of 1.8–300 K.     

Cobalt(II) and silver(I) coordination polymers containing flexible bis (benzimidazol-1-yl)hexane ligands: synthesis,crystal structures,sensing and photocatalytic properties

Two new ternary metal coordination polymers (CPs), namely, {[Co₂(BTC)(L)]·0.25H₂O}_n ( 1 ) and [Ag(HIPA)(L)]_n ( 2 ) (H₄BTC = 1,2,3,4-butanetetracarboxylic acid, H₂IPA = isophthalic acid, L = 1,6-bis(5,6-dimethylbenzimidazol-1-yl)hexane) were hydrothermally synthesized and characterized by elemental analysis, infrared spectroscopy, single-crystal X-ray diffraction, and powder X-ray diffraction (PXRD). 1 exhibits unusual 2D network with point symbol {4³.6³}₂{4⁶.6⁶.7³}. 2 possesses 1D chain structure which is further extended into a 3D supramolecular network via O–H···O hydrogen-bonding and π–π stacking interactions. 1 and 2 can selectively detect benzaldehyde (BZH), Fe³⁺ (just 1 ) and Cr₂O₇²⁻ (just 2 ) ions in water via the luminescence quenching process. Furthermore, the photocatalytic activities of two CPs were evaluated for degradation of methylene blue (MB) and methyl violet (MV) under UV irradiation.     

Two novel lanthanide(III) organic frameworks based on a biphenyltetracarboxylate ligand: synthesis,structure and magnetic and luminescence properties

Two new two‐dimensional lanthanide coordination polymers, namely poly[[tetra‐μ₂‐acetato‐tetraaquabis(μ₄‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraterbium(III)] pentahydrate], {[Tb₄(C₁₆H₆O₈)₂(C₂H₃O₂)₄(C₄H₉NO)₄(H₂O)₄]·5H₂O}_n, (1), and poly[[tetra‐μ₂‐acetato‐tetraaquabis(μ₅‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraeuropium(III)] tetrahydrate], {[Eu₄(C₁₆H₆O₈)₂(C₂H₃O₂)₄(C₄H₉NO)₄(H₂O)₄]·4H₂O}_n, (2), have been synthesized from biphenyl‐3,3′,5,5′‐tetracarboxylic acid (H₄bpt) and Ln(NO₃)₃·6H₂O (Ln = Tb and Eu) under solvothermal conditions. Single‐crystal X‐ray structure analysis shows that the two compounds are isostructural and crystallize in the monoclinic P2₁/n space group. The crystal structures are constructed from bpt⁴⁻ ligands (as linkers) and {Ln₂(μ₂‐CH₃COO)₂} building units (as nodes), which topological analysis shows to be a (4,6)‐connected network with sql topology. Compounds (1) and (2) have been characterized by elemental analysis, IR spectroscopy, powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA) and fluorescence analysis in the solid state. In addition, a magnetic investigation shows the presence of antiferromagnetic interactions in compound (1).