Syntheses and characterizations of copper(II) polymeric complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Four polymeric complexes with rectangular grids or channels, [Cu2(btec)(H2O)4*2H2O]n (2), [Cu2(btec)4/4[Cu(Hbtec)2/2(4,4'-Hbpy)(H2O)2]2*4H2O]n (3), [Cu2(btec)(hmt)(H2O)4*8H2O]n (4), and [Cu3(btec)(OH)2]n (5), were designed and constructed from Cu(II) ion and 1,2,4,5-benzenetetracarboxylic acid along with auxiliary ligands (where H4btec = 1,2,4,5-benzenetetracarboxylic acid, 4,4'-Hbpy = monoprotonated 4,4'-bipyridine, and hmt = hexamethylenetetramine). Complexes 2, 3, and 4 have rectangular pores with the size of 6.5 A x 4.5 A, 6 A x 7 A, and 10.1 A x 11.8 A, respectively, while 5 has a channel of 7.4 A x 9.6 A. The complexes show interesting magnetic properties due to the different coordination modes of the carboxylate groups and the presence of auxiliary ligands. On lowering the temperature, the magnetic interactions in 2 are changed from antiferromagnetic to ferromagnetic. For 3, the antiferromagnetic interactions weaken sharply at low temperature. Complex 4 shows ferromagnetic interactions while 5 is antiferromagnetic.     

Synthesis and characterization of two 3-D polymeric lanthanide complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Two 3-D porous coordination polymers, [Nd(^abtec)_2/4(^bbtec)_2/4(H₂O)] _n (1) and [NdYb(^cbtec)_2/4(^dbtec)_2/4(^ebtec)_2/4(H₂O)₄] _n (2), have been prepared by the hydrothermal method at 160°C. Both complexes were characterized by elemental analyses, photoluminescence spectra, and single-crystal X-ray diffraction.     

Synthesis and characterization of two 3-D polymeric lanthanide complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Two new 3-D lanthanide coordination polymers, [CeK(btec)(H₂O)₂] _n (1), [Ho(btec)_0.5(ad)_0.5(H₂O)] _n (2) (H₄btec?=?1,2,4,5-benzenetetracarboxylic acid, H₂ad?=?adipic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that both complexes crystallized in monoclinic space group P2₁/c and possessed 3-D net-structures. In 1, btec adopts two types of coordination modes: µ₁₂–η²:η²:η²:η¹:η²:η²:η²:η¹ bridging mode linking six Ce(III) ions and six K⁺ ions and the other µ₈–η¹:η²:η²:η¹:η¹:η²:η²:η¹ bridging mode connecting four Ce(III) ions and four K⁺ ions. In 2, btec adopts a µ₆-bridging with each carboxylate group of btec ligand in a µ₂–η¹–η² mode, the adipate is µ₄-bridging with each carboxylate µ₂–η¹–η¹-monodentate. The topological analysis shows that 1 can be simplified to a 3-nodal net with the Schläfli symbol {3²,4⁸,5³,6²}₄{3⁴,4¹²,5¹²}{4³⁸,6²⁶,8²} and 2 can be simplified to a 3-nodal network with the Schläfli symbol {4²,8⁴}{4⁶,6⁶,8³}{4⁷,6³}₂. The thermogravimetric analyses and the X-ray powder diffraction of 1 and 2 are discussed.     

Extraction of europium complexes with 1,2,4,5-benzenetetracarboxylic acid and neutral ligands

Extraction of mixed-ligand europium complexes with 1,2,4,5-benzenetetracarboxylic (pyromellitic) acid and neutral ligands was studied. The complexation of europium with the ligands is discussed on the basis of data on europium distribution in extraction systems, as well as IR and luminescent spectroscopy data of extracts. Crystalline polynuclear europium complexes with pyromellitic acid and 1,10-phenanthroline and tris(hydroxymethyl)aminomethane were isolated from the extracts. The composition of pyrolysis products of extracts was studied. It was shown that nanosized bulk samples of europium oxide can be obtained by the pyrolysis of saturated extracts. Differences in the morphology of europium oxide nanoparticles were revealed in the samples obtained by pyrolysis of extracts differing in composition at the same temperature and time.     

Functional self-assembly of hydrogen-bonded 3D coordination networks constructed from 1,2,4,5-benzenetetracarboxylic acid

Hydrothermal synthesis, characterization (IR, TG/DTA, element analysis, inductively coupled plasma (ICP)) and single-crystal X-ray structures of H₄Btec hydrate and its two cobalt complexes, colorless [H₄Btec · 2H₂O] _n (I), pink [Co(H₂O)₆(H₂Btec)] _n (II), and nacarat {[Co(H₂O)₃(H₂Btec)(Phen)] · H₂O} _n (III) (H₄Btec = 1,2,4,5-benzenetetracarboxylic acid, Phen = 1,10-phenanthroline) have been solved. The results showed that I forms a 3D O-H⋯O hydrogen-bonded network generated from H₄Btec and water molecules, II presents a 3D network constructed by mononuclear [Co(H₂O)₆]²⁺ cations and H₂Btec²⁻ dianions through extensive hydrogen-bonding interactions, and III gives rise to a pseudo-octahedral coordination geometry. Extensive hydrogen-bonding interactions have significant effects in configuring a 3D network constructed by mononuclear [Co(H₂Btec)(Phen)(H₂O)₃] neutral molecules and a water molecules. The article was submitted by the authors in English.     

Syntheses and luminescence of three lanthanide complexes constructed by flexible carboxylate ligand

Three new complexes, namely {[Ln(L)₃(2,2′-Bipy)] _n · H₂O} (Ln = Pr (I), Sm (II), and Nd (III)) (HL = 3-(2-hydroxyphenyl)propanoic acid), have been synthesized and structurally characterized. The structural determinations indicated (CIF files CCDC nos. 1472729 (I), 1472730 (II), 1472734 (III)) that I–III have similar dinuclear structures, which can be further linked into 2D sheet via the hydrogen bond interactions. Furthermore, the luminescent properties of I–III show the strong emissive power and feature.     

Hydrothermal synthesis, crystal structure, and photoluminescence of novel lanthanide metal organic frameworks constructed from 1,4-benzene-dicarboxylic acid and 1,2,4,5-benzenetetracarboxylic acid as ligands

Abstract  

By using 1,4-benzene-dicarboxylic acid and 1,2,4,5-benzenetetracarboxylic acid as mixed-linkers, three novel 3D lanthanide coordination polymers, [Ln(BDC)_0.5(BTEC)_0.5(H₂O)] (Ln = Eu (1) and Gd (2)) and [Tb(BDC)_0.5(BTEC)_0.5(H₂O)] (3) (H₂BDC = 1,4-benzene-dicarboxylic acid, H₄BTEC = 1,2,4,5-benzenetetracarboxylic acid) were synthesized via hydrothermal reaction. The X-ray single crystal analyses reveal that the three coordination polymers present two types of different crystal cell parameters and hereby exhibited two kinds of different metal–organic frameworks, although they have the similar chemical formula [Ln(BDC)_0.5(BTEC)_0.5(H₂O)]. Of these complexes, complexes 1 and 2 are isomorphous, crystallizing in monoclinic, space group P2₁/n. While 3 is a 3D eight-coordinated terbium complex with triclinic crystal system and P-1 space group. The occurrence of the different structures of these complexes under the similar preparation method may be related to the lanthanide contraction effect. Additional, the thermogravimetric analyses and photoluminescent properties for complexes 1 and 3 were discussed in detail.     

Synthesis and characterization of metal polycarboxylates constructed from lanthanides(iii) and 1,2,4,5-benzenetetracarboxylic acid

The complexes of yttrium(III) and lanthanides(III) with 1,2,4,5-benzenetetracarboxylic acid were prepared as crystalline solids of the general formula Ln₄(C₁₀H₂O₈)₃⋅14H₂O. They are insoluble in water. On heating in air or inert gas atmosphere all compounds lose water molecules; next anhydrous compounds decompose to oxides. The yttrium complex and heavy lanthanide (from Ho to Lu) ones crystallize in monoclinic crystal system. The dehydration does not change the crystal structure of the compounds.     

Syntheses, structures and properties of silver-organic frameworks constructed with 1,2,3,4-benzenetetracarboxylic acid

The reactions of 1,2,3,4-benzenetetracarboxylic acid (H(4)mpda) and different silver(I) salts under hydrothermal or solvent evaporation conditions yielded four unusual coordination complexes with interesting frameworks: [Ag(4)(mpda)](n) (1), {[Ag(2.5)(mpda)(bpy)(2)]·[Ag(bpy)]·[Ag(bpy)(H(2)O)]·(NO(3))(0.5)·(H(2)O)(9)}(n) (2), {[Ag(5)(mpda)(2)(bpy)(4)]·[Ag(bpy)]·[Ag(bpy)(H(2)O)]·[Ag(bpy)(H(2)O)]·(H(2)O)(16)}(n) (3), {[Ag(2)(mpda)(H(2)O)]·[Ag(bpy)]·[Ag(bpy)]}(n) (4) (bpy = 4,4'-bipyridine). Complex 1 displays a novel (3,4,7)-connected {4.6(2)}{4.6(5)}{4(2).6(13).8(5).10} topology, in which the carboxylic groups of the mpda(4-) ligand adopt variable coordination modes. In 1, besides Ag-O coordination bonding, AgAg and Agaromatic intermolecular interactions also make their appearance. In complexes 2-4, rare architectures comprising three or four isolated coordination polymers within the same crystalline structure have been obtained, respectively. In 2 and 3, neighboring layers are linked together through water tapes into a three-dimensional supramolecular architecture, which is also consolidated by π···π stacking, while independent infinite rod-like polymer chains fill the void space between layers. Interestingly, an anionic (H(2)O-NO(3)(-))(n) layer, built from water tapes and nitrate anions as well as consolidated by the mpda(4-) ligands, has been structurally identified in compound 2. A new water tape constructed from alternating tetramers and decamers has been obtained in compound 3. In compound 4, a right-handed helical chain and two rod-like polymeric chains are interconnected through host-guest molecular recognition to generate a three-dimensional chiral supramolecular architecture. Bulk materials for 1 and 4 have second-harmonic generation activity, being approximately 0.6 and 0.4 times that of urea. The IR spectra, thermogravimetric analysis and luminescent properties of all compounds were also investigated.     

1-甲基-1-乙基-3-丁烯基环戊二烯基稀土二氯化物的 合成与表征

报道了1-甲基-1-乙基-3-丁烯基环戊二烯基稀土二氯化物的合成。用元素分析、质谱、红外光谱和核磁共振表征了这类配合物的组成为[C~5H~4C(CH~3)(C~2H~5)CH~2CH＝CH~2]LnCl~2·MgCl~2·THF[Ln=La(1),Nd(2),Sm(3),Gd(4)]。     

Syntheses,structures, and characterizations of three Ag(I) complexes constructed by length-modulated pyrazole-based ligands

Three coordination complexes with N-donor ligands, Ag₂(L1)_1.5(NO₃)₂ (1), Ag₃(L2)₂(NO₃)₃ (2), and Ag(L1)₂NO₃ (3) {L1?=?1,4-bis(pyrazole-1-ylmethyl)benzene, L2 = 4,4′-bis(pyrazole-1-ylmethyl)biphenyl}, have been synthesized and structurally characterized by elemental analysis, IR spectroscopy, TGA, and X-ray single crystal diffraction. Complex 1 shows a 3-D fsh-3,4-P2₁/c structure with brevity code {8³}²{8⁵·10}. Complex 2 has a 3-D framework with a 2-D layer penetrated by an infinite 1-D zigzag chain. Complex 3 exhibits a (4,4)-net racemizing layer structure with nitrate anions filling the cavity. The results indicate that L1 and L2 can adopt varied conformations in formation of the complexes, and the length of the ligands plays a key role in configuring and directing the corresponding structure of the complexes.     

Syntheses,crystal structures,and properties of two dinuclear iron(III) complexes constructed with 1,2,3,5-benzenetetracarboxylic acid and chelating N-donor auxiliary coligands

Two dinuclear Fe(III) metal–organic complexes with tetracarboxylate and chelating N-donor ligands, [Fe(Hbtec)(phen)(H₂O)]₂·2H₂O (1) and [Fe(Hbtec)(bpy)(H₂O)]₂·2H₂O (2) (H₄btec = 1,2,3,5-benzenetetracarboxylic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) have been prepared and characterized by elemental analysis, IR spectroscopic, and X-ray diffraction methods. Both complexes crystallize in the monoclinic space group P2₁/c with two Fe(III) ions bridged by two Hbtec^3? ligands into a dinuclear unit. Hydrogen bonding connects the dinuclear units into a 3-D framework. The dinuclear units are 10-connected nodes that produce a 3-D framework with topology Schläfli symbol as (3¹²·4²⁸·5⁵). Thermal stabilities and luminescent properties of the two complexes have also been investigated.     

Novel one-dimensional lanthanide acrylic acid complexes: an alternative chain constructed by hydrogen bonding

Novel one-dimensional (1D) chains of three lanthanide complexes La(L¹)₃(CH₃OH)]·CH₃OH (L¹=(E)-3-(2-hydroxyl-phenyl)-acrylic acid) 1, La(L²)₃(H₂O)₂]·2.75H₂O (L²=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) 2, and La(L³)₃(CH₃OH)₂(H₂O)]·CH₃OH (L³=(E)-3-(4-hydroxyl-phenyl)-acrylic acid) 3 are reported. The crystal structure data are as follows for 1: C₂₉H₂₉LaO₁₁, monoclinic, P2₁/n, a=15.4289(12) Å, b=7.9585(6) Å, c=23.041(2) Å, β=99.657(2)°, Z=4, R₁=0.0637, wR₂=0.0919; for 2: C₂₇H_30.50LaO_13.75, triclinic, P−1, a=8.4719(17) Å, b=13.719(3) Å, c=14.570(3) Å, α=62.19(3)°, β=99.657(2)°, γ=78.22(3)°, Z=2, R₁=0.0384, wR₂=0.0820; and for 3: C₃₀H₃₅LaO₁₃, monoclinic, P2(1)/c, a=9.5667(6) Å, b=24.3911(15) Å, c=14.0448(9) Å, β=109.245(2)°, Z=4, R₁=0.0374, wR₂=0.0630. All the three structure data were collected using graphite monochromated molybdenum Kα radiation and refined using full-matrix least-squares techniques on F². These structures show that four kinds of the carboxylato bridge modes are included in these chains to link the La(III) ions. It is the first time that it has been found that the intra-chain hydrogen bonding can construct an alternative chain even, when the coordination bridge mode is the same along the chain (complex 2). There are 2D and 3D hydrogen bonding in the crystal lattices of complexes 1-3.     

Supramolecular networks constructed from mono- and bi-nuclear lanthanide complexes with 1,2-phenylenedioxydiacetic acid

[Tb₂(1,2-pdoa)₃ · 6H₂O] · H₂O (1) and [La(1,2-pdoa)(1,2-H₂pdoa)(OH) · H₂O] · 5H₂O (2) (1,2-H₂pdoa = 1,2-phenylenedioxydiacetic acid) have been synthesized and structurally characterized by single crystal X-ray diffraction. Complex 1 is a binuclear molecule in which one 1,2-pdoa ligand is a tetradentate bridge linking two Tb³⁺ ions, the other two 1,2-pdoa ligands bond Tb1³⁺ and Tb1A³⁺ via tetradentate chelating coordination. Tb³⁺ is nine-coordinate by six oxygens of 1,2-pdoa and three waters. Complex 2 is mono-nuclear with La³⁺ ten-coordinate by eight oxygens of two 1,2-pdoa, one hydroxide and one water. 1,2-Pdoa is tetradentate chelating with La³⁺ ion. The packing diagrams of 1 and 2 show supramolecular networks via H-bonds. The fluorescence spectrum of 1 shows characteristic emission of Tb³⁺ with ⁵D₄ → ⁷F_j (j = 6–3) transitions.     

Syntheses,characterization and thermal properties of lanthanide complexes with 2-mercaptonicotinic acid

Fourteen new complexes with the general formula of Ln(Hmna)₃·nH₂O (n=2 for Ln=La-Ho and n=1 for Er-Lu, H₂mna=2-mercaptonicotinic acid) were synthesized and characterized by elemental analyses, IR spectra and thermogravimetric analyses. In addition, molar specific heat capacities were determined by a microcalorimeter at 298.15 K. The IR spectra of the prepared complexes revealed that carboxyl groups of the ligands coordinated with Ln(III) ions in bidentate chelating mode. Hydrated complexes lost water molecules during heating in one step and then the anhydrous complexes decomposed directly to oxides Ln₂O₃, CeO₂, Pr₆O₁₁ and Tb₄O₇. The values of molar specific heat capacities for fourteen solid complexes were plotted against the atomic numbers of lanthanide, which presented as ‘tripartite effect’. It suggested a certain amount of covalent character existed in the bond of Ln³⁺ and ligands, according with nephelauxetic effect of 4f electrons of rare earth ions.     

Mixed-ligand lanthanide complexes constructed by flexible 1,3-propanediaminetetraacetate and rigid terephthalate

Abstract

Coordination polymers (CPs) of mixed-ligand lanthanide complexes [Ln₂(1,3-pdta)(TPA)(H₂O)₂]_n·nH₂O [Ln?=?La, 1; Ce, 2; Pr, 3; Nd, 4] (1,3-H₄pdta = 1,3-propanediaminetetraacetic acid; H₂TPA?= terephthalic acid) were hydrothermally synthesized with flexible 1,3-pdta and rigid TPA ligands. Moreover, lanthanide propanediaminetetraacetates [Ln(1,3-Hpdta)(H₂O)]_2n·nH₂TPA·xH₂O [Ln?=?Sm, 5; Gd, 6] with multi-layered structures were also obtained. In 1–4, both 1,3-pdta and TPA coordinate with lanthanide ions through carboxyl oxygen and nitrogen atoms. In 5 and 6, only 1,3-Hpdta coordinates with the central lanthanide ion, where one nitrogen atom in 1,3-Hpdta is protonated, and TPAs are crystallized as H₂TPA with the central multi-layered structures of [Ln(1,3-Hpdta)(H₂O)]_2n through very strong hydrogen bonds [2.504(4) Å]. Solid-state ¹³C NMR analysis of 1 revealed the coordination of carboxyl groups. However, the methylene groups of 1,3-pdta showed an obvious upfield shift, which can be attributed to the effects of the phenyl ring in TPA ligand. The successful synthesis of these mixed-ligand lanthanides provides a rational design of such lanthanide CPs with flexible and rigid ligands.     

A rational study of crystal engineering of supramolecular assemblies of 1,2,4,5-benzenetetracarboxylic acid

Supramolecular assemblies of 1,2,4,5-benzenetetracarboxylic acid, 1, with aza donor molecules such as 1,10-phenanthroline, 2, 1,7-phenanthroline, 3, phenazine, 4, 4-(N,N-dimethylamino)pyridine, 5, 1,2-bis(4-pyridyl)ethene, 6, and 1,2-bis(4-pyridyl)ethane, 7, have been synthesized and characterized by single-crystal X-ray diffraction methods. All the complexes crystallize in the triclinic, Ponemacr; space group. In the complexes of 2 and 4, water is also present in the resultant assembly, but the complexes of 5, 6, and 7 crystallize without any water molecules or solvent of crystallization. However, 3 forms two types of complexes, a hydrate and a nonhydrate complex, depending upon whether water is used as a solvent or not. These assemblies divide into two classes, host-guest systems (with aza molecules being in the channels created by the acid molecules) and assemblies with infinite molecular tapes. While the assemblies of the compounds 2, 4, and 5 belong to the former class, the assemblies of compounds 6 and 7 form molecular tapes, which are arranged in two dimensions to form sheet structures. The two structures of 3, in fact, bridge the two classes with each one falling into different categories.     

Syntheses and characterizations of five coordination polymers constructed by 3,5-bis(pyridin-3-ylmethoxy)benzoic acid ligand

Five coordination polymers, namely [Cd(L3)₂]·H₂O (1), [Zn(L3)₂] (2), [Co(L3)₂] (3), [Ni(L3)₂] (4) and [Cu₂(L3)₂]·3H₂O (5), where L3 = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compound 1 is a binodal (3,4)-connected net with (6³)(6⁶) topology. Compounds 2–4 are isostructural and described by the uninodal (4,4)-connected net with (4⁴ · 6²) Schläfli symbol. The structure of 5 is a 2D binodal (6,3) net. In addition, the luminescent properties of compounds 1 and 2 have been studied in the solid state at room temperature.     

Syntheses and characterizations of group 6 metal cyanotrihydroborate complexes

The anions, [M(CO)_6-n(NCBH₃)_n]ⁿ⁻ (n=2, M=Cr(1); n=3, M=Cr(2), Mo(3), W(4)), were prepared either from the reactions of sodium cyanotrihydroborate with group 6 transition metal hexacarbonyls, M(CO)₆ (M=Cr, Mo, W), or through the reactions of M(CO)₃(CH₃CN)₃ (M=Cr, W) with sodium cyanotrihydroborate. The cyanotrihydroborate ligand bonds to the metal through a nitrogen atom, which was confirmed by the Infrared, proton and boron NMR spectroscopies. Crystal structures of the above complexes were determined by single crystal X-ray diffraction analyses. A cis configuration is found in 1. Molecular structures of 2, 3, and 4 are similar and a facial configuration is observed.