Hydrothermal syntheses,and crystal structures of new lanthanide coordination polymers with nitrilotriacetic acid

Hydrothermal reactions of Nd(ClO₄)₃·6H₂O, Gd(ClO₄)₃·6H₂O and Er₂O₃ with H₃NTA (nitrilotriacetic acid) afford three new lanthanide coordination polymers, {[Nd(NTA)(H₂O)]· 2H₂O} _n (1), {[Gd(NTA)(H₂O)]·2H₂O} _n (2) and {[Er(NTA)(H₂O)]·H₂O} _n (3), characterized by elemental analysis and IR spectroscopy. X-ray single crystal structural analyses showed that 1 and 2 are an isomorphous 2D-layered framework containing the nine-coordinated Nd(III) (or Gd(III)), and woven into a 3D suprastructure by interlayer hydrogen bonding while 3 is a 3D structure with eight-coordinate Er(III).     

Three lanthanide coordination polymers with nitrilotriacetic acid: hydrothermal syntheses,crystal structures and fluorescent property

Hydrothermal reactions of Sm₂O₃, Gd(ClO₄)₃?·?6H₂O and Tb(ClO₄)₃?·?6H₂O with nitrilotriacetic acid, give rise to three lanthanide coordination polymers, {[Sm(NTA)(H₂O)₂]?·?H₂O} _n (1), {[Gd(NTA)(H₂O)]?·?H₂O} _n (2) and {[Tb(NTA)(H₂O)]?·?H₂O} _n (3). Their solid-state structures have been characterized by elemental analysis, and IR spectroscopy. X-ray single-crystal diffraction analyses indicated that 2 and 3 are isomorphous three-dimensional coordination polymers with eight-coordinate Gd(III) (or Tb(III)), while 1 forms a two-dimensional coordination polymer containing nine-coordinate Sm(III). The photophysical properties of 3 have been studied with excitation and emission spectra, which exhibit strong green emission.     

Dinuclear rare-earth picrate complexes based on a multidentate amide ligand: syntheses,crystal structures,and luminescence properties

A new amide-based multidentate ligand, N,N′-1,2-ethanediyl-bis{2-[(N,N-diethylcarbamoyl)methoxy]benzamide} (L) reacts with M(Pic)₃?·?6H₂O to give rare-earth picrate complexes [M₂L₂(Pic)₄(H₂O)₂](Pic)₂ (M = La (1), Nd (2), Eu (3), Gd (4), Tb (5), Dy (6), Yb (7), Y (8)). X-ray single-crystal diffraction analyses indicate that dinuclear complexes 3?·?2C₄H₈O₂, 6?·?2C₄H₈O₂, and 8?·?2CH₃CN are isomorphous. Each metal is nine-coordinate by four oxygen atoms of two ligands, four oxygen atoms of two bidentate picrates, and one water molecule with a distorted monocapped square antiprism. With hydrogen bonds between the free picrate anions and the coordination cations the complexes exhibit 2-D layers. The luminescent properties of 3 [Eu₂L₂(Pic)₄(H₂O)₂](Pic)₂ are described and factors that influence luminescent intensities are also discussed.     

Syntheses,crystal structures and fluorescent properties of four one-dimensional lanthanide coordination polymers with 3-cyanobenzoato

The hydrothermal reactions of Nd(ClO₄)₃·6H₂O, Gd(ClO₄)₃·6H₂O, Dy(ClO₄)₃·6H₂O, Er(ClO₄)₃·6H₂O with 1,3-dicyanobenzene, give rise to four one-dimensional rare earth-based coordination polymers: [M(3-CNC₆H₄COO)₃(H₂O)₂] _n (where M?=?Nd (1), Gd (2), Dy (3), Er (4), 3-CNC₆H₄COO?=?3-cyanobenzoato), respectively. Their solid-state structures have been characterized by X-ray single-crystal diffraction studies. The results show that 1,3-dicyanobenzene hydrolyzed to give 3-cyanobenzoato under hydrothermal condition, and the four complexes are isomorphous. Crystal data for 1: triclinic, space group P-1, a?=?9.4063(19), b?=?11.485(2), c?=?12.616(3)?Å, α?=?66.38(3), β?=?74.01(3), γ?=?86.96(3)°, V?=?1197.9(4)?ų, Z?=?1, D _c?=?1.704?Mg?m^?3; for 2: triclinic, space group P-1, a?=?9.3712(19), b?=?11.446(2), c?=?12.627(3)?Å, α?=?65.86(3), β?=?73.89(3), γ?=?86.84(3)°, V?=?1184.8(4)?ų, Z?=?1, D _c?=?1.759?Mg?m^?3; for 3: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.780?Mg?m^?3; for 4: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.7794?Mg?m^?3. The fluorescence emission spectra of compounds 1 to 4 are also reported.     

Two binuclear lanthanide complexes with 4-quinoline carboxylic acid: crystal structures and luminescent properties

Two isomorphic lanthanide complexes [Eu₂(L)₆(H₂O)₄] · 2H₂O (1) and [Tb₂(L)₆(H₂O)₄] · 2H₂O (2), (HL = 4-quinoline carboxylic acid) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Both complexes are binuclear and each metal center adopts nine-coordination with nine oxygens from two H₂O molecules and carboxylates of three ligands; L exhibits three different coordination modes. Luminescent properties of 1 and 2 at room temperature indicate that the triplet-state level of this ligand matches better with the lowest excited state level of Eu(III) than with Tb(III).     

Dinuclear Zn(II) and Hg(II) complexes of an angular dipyridyl ligand: syntheses,crystal structures,and properties

The angular polytopic dipyridyl ligand 2,6-bis(quinoline-2-carboxamido)pyridine (H₂L) was prepared. Assemblies of H₂L with ZnAc₂ and HgAc₂ resulted in two new dinuclear complexes [Zn₂(L)(Ac)₂]?·?1.5H₂O?·?0.5CH₃OH (1) and [Hg₂(L)(Ac)₂]?·?5H₂O?·?CH₃OH (2) where the doubly deprotonated L^2? bi-chelate as μ-kN,N′?:?kN″,N″′, bridging the two metal centers (Ac?=?acetate). In 1, the two Zn(II) ions are also doubly bridged by two Ac ions in a μ-kO?:?kO′ coordination, and thus each metal center adopts a distorted tetrahedral geometry. In 2, each Ac ion is only terminal to Hg(II), in a rare distorted triangular or T-shaped coordination geometry. Free H₂L, 1, and 2 emit interesting bluish-green fluorescence with strong intensities. Thermogravimetric analysis of 1 shows that the dinuclear structure of 1 is stable to 382°C.     

Different crystal structure and photophysical properties of lanthanide complexes with 5-bromonicotinic acid

Five novel lanthanide (Eu³⁺ (1), Tb³⁺ (2), Sm³⁺ (3), Dy³⁺ (4) and Gd³⁺ (5)) complexes with 5-Bromonicotinic acid (5-Brnic) were synthesized and two of them (Tb³⁺, Sm³⁺) were characterized by X-ray diffraction. The results reveal that {[Tb(5-Brnic)₃(H₂O)₃]·H₂O}_n (2) and [Sm(5-Brnic)₃(H₂O)₂·H₂O]₂ (3) exhibit different coordination geometries and crystal structures. Complex 2 has a one-dimensional chain-like polymeric structure through the bridged 5-Brnic anions which links up two neighboring terbium ions, while Complex 3 forms a dimeric molecular structure. The lowest triplet state energy of 5-Brnic was determined to be 24 330 cm⁻¹ corresponded to the 0-0 transition in the phosphorescence spectrum of its gadolinium complex at 411 nm. The strong luminescent emission intensities of these complexes indicated that the triplet state energy of 5-Brnic is suitable for the sensitization of luminescence of Eu³⁺, Tb³⁺, Sm³⁺ and Dy³⁺, especially for that of Tb³⁺ and Dy³⁺.     

Synthesis,structures, and fluorescent properties of two oxalato-bridged dinuclear zinc(II) complexes with tridentate and tetradentate polybenzimidazole ligands

Two dinuclear oxalato-bridged zinc(II) complexes, [Zn₂(bbma)₂(μ₂-η⁴-ox)](ClO₄)₂ (1) and [Zn₂(ntb)₂(μ₂-η²-ox)](ClO₄)₂·4CH₃OH (2), containing tridentate and tetradentate polybenzimidazole ligands were synthesized, where bbma is bis(benzimidazol-2-yl-methyl)amine and ntb is tris(2-benzimidazolylmethyl)amine. They were characterized by single-crystal X-ray diffraction, elemental analysis, IR, and fluorescence spectroscopy. Zinc(II) complexes in 1 and 2 are five-coordinate in distorted trigonal bipyramidal geometry. Oxalate bridges two zinc(II) ions as a bis-bidentate chelate in 1, while bis-monodentate in 2. The Zn?Zn distances are 5.318(1)?Å for 1 and 7.1295(5)?Å for 2, respectively. 1-D chain structures are formed in 2 by intermolecular hydrogen bonds. The solid state fluorescence spectra have been studied for 1 and 2.     

Hydrothermal syntheses,crystal structures and antibacterial activities of two transition metal complexes with ciprofloxacin

Hydrothermal reactions of ciprofloxacin with Co(OH)₂, and with oxalate and Fe(OH)₃, yield [Co(Cip)₂] · 2H₂O (1) and [Fe(H-Cip) · (C₂O₄)] · (H₂Cip) · 5H₂O (2), which were characterized by elemental analysis, IR and single crystal diffraction analyses. Compounds 1 and 2 were screened for antibacterial activities against Staphylococcus aureas, Escherichia coli, Candida albicans and Pseudomonas aeruginosa.     

Synthesis,crystal structures,and catalytic properties of phenoxo-bridged dinuclear manganese(III) complexes with bis-Schiff bases

Two structurally similar centrosymmetric phenoxo-bridged dinuclear manganese(III) complexes, [Mn₂(L¹)₂(N₃)₂] (1) and [Mn₂(L²)₂(NCS)₂] (2), were prepared from the tetradentate bis-Schiff base ligands, N,N’-bis(salicylidene)propane-1,2-diamine (H₂L¹) and N,N’-bis(salicylidene)ethane-1,2-diamine (H₂L²), respectively, in the presence of pseudohalides. The complexes have been characterized by FTIR, elemental analyses, and molar conductivity. Structures of the complexes have been confirmed by single-crystal X-ray determination. The bis-Schiff base ligands coordinate with Mn through their phenolate oxygen and imino nitrogen. Each Mn is an octahedral. The complexes showed that they exhibit high activity in catalytic olefin oxidation.     

Three lanthanide complexes with mixed salicylate and 1,10-phenanthroline: syntheses,crystal structures,and luminescent/magnetic properties

Three new lanthanide complexes incorporating salicylate (HSA or SA) and 1,10-phenanthroline (phen), Ln₃(HSA)₅(SA)₂(phen)₃ [Ln = Ho (1) and Er (2)], and Sm₂(HSA)₂(SA)₂(phen)₃ (3), have been synthesized. X-ray structural analysis reveals that 1 and 2 are isostructural with a trinuclear pattern, and 3 exhibits a binuclear structure. Comparison of the structural differences between 1/2 and 3 suggests that the identity of metal plays an important role in construction of such complexes. The magnetic properties of 1 are discussed. Moreover, 2 and 3 are both photoluminescent materials, and their emission properties are closely related to their corresponding Ln^III centers.     

Hydrothermal synthesis and crystal structure of two new lanthanide coordination polymers with 1,2-phenylenediacetate

Two new compounds {[Ln₂(1,2-pda)₃(H₂O)₂]·?2H₂O} _n (1,2-H₂pda?=?1,2-phenylenediacetic acid, Ln?=?Tb, 1; Ho, 2) were prepared by hydrothermal reaction and characterized by X-ray crystallography. The Ln³⁺ is nine-coordinate by eight oxygen atoms of six 1,2-pda ligands and one oxygen of water. Ln³⁺ ions are bridged by 1,2-pda ligands via bridging/chelating-bridging pentadentate and chelating-bridging/chelating-bridging hexadentate coordination to form 3-D framework structures. Complex 1 emits strong green fluorescence corresponding to ⁵D₄???⁷F_j (j?=?6–3) transitions of the Tb³⁺.     

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.     

Hydrothermal syntheses,crystal structures and antibacterial activities of two Cu(II) complexes with quinolones

Hydrothermal reactions of ciprofloxacin with Cu(ClO₄)₂?·?6H₂O, and ofloxacin with Cu(CH₃COO)₂?·?4H₂O, yield two metal complexes: [Cu(H-Cip)₂]?·?(ClO₄)₂?·?6H₂O (1) and [Cu(Ofl)₂?·?H₂O]?·?2H₂O (2), which were characterized by elemental analysis, IR and single crystal diffraction analyses. Compounds 1 and 2 were screened for antibacterial activities against Staphylococcus aureus, Escherichia coli, Candida albicans and pseudomonas aeruginosa.     

Synthesis, crystal structures, and luminescent properties of two types of lanthanide phosphonates

Hydrothermal reactions of different lanthanide(III) salts with an amino-diphosphonate ligand (H₄L=C₆H₅CH₂N(CH₂PO₃H₂)₂) led to two series of lanthanide phosphonates, namely, Ln(H₂L)(H₃L) (Ln=La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; Tb, 7). Compounds 1-5 feature a one-dimensional (1D) chain structure in which dimers of two edge-sharing LnO₈ polyhedra are interconnected by bridging phosphonate groups, such 1D arrays are further interlinked via strong hydrogen bonds between non-coordinated phosphonate oxygen atoms into a two-dimensional (2D) layer with the phenyl groups of the ligands orientated toward the interlayer space. Compounds 6 and 7 also show a different 1D array in which the LnO₆ octahedra are bridged by phosphonate groups via corner-sharing, such chains are also further interlinked by hydrogen bonds into a 2D supramolecular layer. Compounds 5 and 7 emit red and green light with a lifetime of 2.1 and 3.7 ms, respectively.     

Synthesis,crystal structure,electrochemical and magnetic properties of dinuclear complexes with strong electron-drawing groups in the diphenoxo-tetraaza macrocyclic ligand

Three symmetrical macrocyclic dinuclear complexes [M₂L(H₂O) _n ](ClO₄)₂ (M²⁺ = Cu²⁺, Ni²⁺, Mn²⁺ and n = 0, 2) have been synthesized by cyclocondensation between 2,6-diformyl-4-fluorophenol and 1,4-diaminobutane in the presence of M²⁺ cations. The crystal structure of [Cu₂L](ClO₄)₂ was determined by X-ray diffraction techniques. The electronic and magnetic properties of the complexes were studied by cyclic voltammetry and magnetic susceptibility. The results confirm that the complexes obtain electrons easily and there are very strong antiferromagnetic couplings between two copper(II) ions in [Cu₂L](ClO₄)₂. The strong electron-drawing groups of fluorine attached to the phenyl ring of a macrocyclic complex enhances the antiferromagnetic exchange of the complex and makes it more easily reduced than its analogs.     

Synthesis,spectral characterization,crystal structures of lanthanide(III) pyrrolidine dithiocarbamate complexes and their catalytic activity

A series of lanthanide(III) pyrrolidine dithiocarbamate complexes [Ln(Pyrrol-Dtc)₃(Phen)] {Pyrrol-Dtc = pyrrolidine dithiocarbamate; Phen = 1,10-phenanthroline; Ln = La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Er(III)} have been synthesized and structurally characterized. The molecular structures of [La(Pyrrol-Dtc)₃(Phen)], [Pr(Pyrrol-Dtc)₃(Phen)], [Sm(Pyrrol-Dtc)₃(Phen)], and [Dy(Pyrrol-Dtc)₃(Phen)] have been confirmed using single crystal XRD studies. The results reveal that in these complexes, the central Ln(III) ion is coordinated to three Pyrrol-Dtc and one Phen and possesses a distorted dodecahedron geometry. Catalytic activity of these complexes in trimethylsilylcyanation reaction has been studied.     

Hydrothermal syntheses and characterization of four 2-D lanthanide coordination polymers with glutarate and 1,10-phenanthroline

Four 2-D coordination polymers Ln₂(phen)₂(C₅H₆O₄)₃ [Ln?=?Pr(1), Eu(2), Er(3), Yb(4), phen?=?1,10-phenanthroline] were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data reveal that these complexes are isostructural. In the asymmetric unit, the two Ln(III) ions are nine-coordinate and have similar coordination environments. The Ln(III) ions are built into 2-D layers by three different coordination modes of glutarate. The resulting 2-D layer forms 3-D supramolecular architecture by two types of π···π stacking interactions. All the complexes were characterized by IR spectra and thermogravimetric analysis, and the emission spectrum shows that Eu₂(phen)₂(C₅H₆O₄)₃ possesses strong luminescence.