Lanthanide Carboxylate Research Articles

A series of novel 2D heterometallic 3d–4f heptanuclear complexes based on the linkages of Ln2(ina)6 chains and [Cu(CN)] chains

Five novel 2D heterometallic coordination polymers, Ln2Cu5(ina)6(CN)5.5·4H2O [Ln = Nd (1), Eu (2), Tb (3), Gd (4), Sm (5); ina = isonicotinic acid], have been synthesized under hydrothermal conditions and characterized by elemental, infrared, thermogravimetric and X-ray diffraction analyses. These complexes are constructed of Ln2(ina)6 chains, Cu–CN–Cu, and CN–Cu–CN chains, which represent the first examples of 3D coordination compounds created by using a combination of metal–cyanide chains, lanthanide–carboxylate linear chains and O–H⋯N hydrogen bonds.

Synthesis, crystal structure and photoluminescent properties of four lanthanide 5-nitroisophthalate coordination polymers

Four new lanthanide coordination polymers, [Y(Hnip)(nip)(H 2O)]·H 2O ( 1), [ Ln(Hnip)(nip)(H 2O) 2]·2H 2O [ Ln=Eu( 2), Tb( 3)] and [Y(nip) 2]·(H 24,4′-bpy) 0.5 ( 4) [5-nip=5-nitroisophthalate, 4,4′-bpy=4,4′-bipyridine], have been hydrothermally synthesized and structurally characterized. Compound 1 features novel lanthanide–carboxylate groups chains composed of three samehanded helical strands intersecting each other through hinged lanthanide atoms, and these chains are cross-linked by phenylene moieties of carboxylate ligands into a 2D layer structure. Compounds 2 and 3 are isomorphous, and contain 1D catenanelike Ln–O–C–O– Ln chains, which are interconnected by phenylene moieties into 2D layer structures. Compound 4, however, displays a 3D architecture sustained by strong hydrogen bonding interactions between the protonated 4,4′-bpy and the carboxyl oxygen atom from [Y 2(nip) 4] 2− with 2D layer structure, and 4,4′-bpy as the guest molecules exist in bilayer channel. The studies for the thermal stabilities of the four compounds show that compound 4 is more stable than other compounds. Compound 2 emits characteristic red luminescence of Eu 3+ ions at room temperature, and its luminescent lifetime and quantum efficiency has been determined.

Synthesis, structures and luminescent properties of 4d–4f heterometallic coordination frameworks based on lanthanide oxalate substructures with nicotinate bridging ligands

Four transition–lanthanide metal–organic coordination polymers, namely [Ag 2Ln(nic) 4(H 2O) 4 · (ClO 4) · H 2O] [Ln = Eu ( 1), Gd ( 2)] and [AgLn(nic) 2(ox) 0.5(H 2O) 2 · (ClO 4) · H 2O] [Ln = Tb ( 3), Yb ( 4)] (nic = nicotinate; ox = oxalate) have been synthesized by the hydrothermal reactions of 4d and 4f metal salts with N-/O-donor ligands. The isostructural complexes 1 and 2 exhibit novel 2D wave-like heterometallic layers constructed by the assembly of 1D chains of lanthanide–carboxylate with Ag(nic) 2 subunits. Complexes 3 and 4 show another unusual 3D heterometallic coordination framework constructed from 2D lanthanide–oxalate layers and pillar-like Ag(nic) 2 subunits. Furthermore, the luminescent properties of complexes 1 and 3 were studied.

3D pillar-layered coordination polymers based on 4d–4f heterometallic assembly

By control of mixed ligands with particular coordination sites, heterometallic coordination polymers, [Ln 2(H 2O) 2Ag(C 2O 4) 2(ina) 3] n (Ln = Eu ( 1), Dy ( 2), Hina = isonicotinic acid) and {[LnAg(C 2O 4)(na) 2]·2H 2O} n (Ln = La ( 3), Tb ( 4), Hna = nicotinic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. These coordination polymers feature 3D pillar-layered coordination frameworks constructed from two-dimensional (2D) lanthanide–carboxylate layers and Ag(ina) or Ag(na) pillars. It is interesting that the in situ decarboxylation of pyridine-2,3-dicarboxylic acid into nicotinic acid was observed. The luminescent properties of 1 and 4 were also studied.

Four distinctive 1-D lanthanide carboxylate coordination polymers: Synthesis, crystal structures and spectral properties

Four novel lanthanide coordination polymers [Pr(mal)(OH)(bipy) · 2H 2O] n ( 1), {[Dy 1(SBA) 3(H 2O) 2][Dy 2(SBA) 3(H 2O) 2] · 4H 2O} n ( 2), {[Tb(OHnic)(Onic)(H 2O) 5 · (OHnicH)] · H 2O} n ( 3) and {[Sm(OHnic)(Onic)(H 2O) 5 · (OHnicH)] · H 2O} n ( 4) (Hmal = maleic acid, HSBA = 4-sulfobenzoic acid, OHnicH = 6-hydroxynicotinic acid and bipy = 2,2′-bipyridine) have been synthesized and determined by single crystal X-ray diffraction. Complex 1 is a 1-D helical chain with seven-coordinated praseodymium centers. Complex 2 forms 1-D chain-like molecular structure containing two crystallographically unique dysprosium centers, the Dy 1 center is seven-coordinated while Dy 2 is eight-coordinated. The isomorphous complexes 3 and 4 exhibit an unprecedented 1-D chain-like polymeric structure through hydroxyl oxygen atoms of bridging Onic 2− anions linking up the neighboring central ions, and there exist three types of 6-OHnicH ligands in the structural unit which is rare for lanthanide carboxylate complexes. The photophysical properties of these complexes were studied using ultraviolet absorption spectra, fluorescence excitation and emission spectra.

Gas-phase synthesis of lanthanide(III) benzoates Ln(Bz)3 (Ln = La, Tb, Lu)

A new method for the synthesis and film deposition of nonvolatile aromatic lanthanide(III) carboxylates by ligand exchange reaction between the starting volatile components in the gas phase was proposed. The complexes Ln(Bz)3 (Ln = La3+, Tb3+, Lu3+, HBz = benzoic acid) were synthesized by gas-phase ligand exchange reaction between the volatile Ln(Thd)3 and HBz (HThd = 2,2,6,6-tetramethylheptane-3,5-dione). The composition of the complexes was confirmed by elemental, thermal, IR-spectroscopic, and photoluminescence analyses and, in the case of lanthanum and lutetium complexes, by 1H NMR.

Direct laser desorption/ionization mass spectrometry characterization of some aromatic lanthanide carboxylates

Abstract The composition of some aromatic terbium carboxylates TbL 3 (HL = Hpobz: 2-phenoxybenzoic acid; HPA: phenylanthranylic acid; HSal: salicylic acid; Habz: anthranylic acid) and their mixed-ligand complexes TbL 3 (TPPO) n (TPPO: triphenylphosphine oxide; n = 1, 2) was studied by direct laser desorption/ionization mass spectrometry (LDI MS). The influence of the ligands composition on the oligomerization of complex molecules and stability of oligomeric ions during LDI MS experiment was established.

The first lanthanide carboxylate complex constructed from hydroxyl bridging bimetallic units: Hydrothermal synthesis, crystal structure and luminescent properties

One novel terbium complex [Tb 2(Dinic) 2(phen) 2(OH) 2(H 2O) 2] n · 3 nH 2O ( 1) has been synthesized by hydrothermal method, where Dinic = 3,4-pyridinedicarboxylate and phen = 1,10-phenanthroline. X-ray crystallography reveals that complex 1 possesses a one-dimensional chain structure constructed from OH − bridging binuclear units, and hydrogen bonding between chains result in a 3D network. The fluorescent properties of complex 1 were investigated in the crystal state.

Selected Controlled Synthesis of Three-Dimensional 4d−4f Heterometallic Coordination Frameworks by Lanthanide Carboxylate Subunits and Silver Centers

By control of mixed ligands with particular coordination sites, three novel three-dimensional (3D) 4d−4f heterometallic coordination polymers, [Ln4(H2O)2Ag(1,3-bdc)4(inic)5]·nH2O (Ln = Nd (1), n = 0.25; Eu (2), n = 0; 1,3-H2bdc = 1,3-benzenedicarboxylic acid and Hinic = isonicotinic acid) and [Nd(H2O)Ag(1,2-bdc)(inic)2] (3) (1,2-H2bdc = 1,2-benzenedicarboxylic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Compounds 1−3 crystallize in the monoclinic system, space group C2/c. Compounds 1 and 2 are isostructural and exhibit novel 3D coordination frameworks constructed from two-dimensional (2D) wavelike lanthanide carboxylate layers and Ag(inic)4 complexes. To the best of our knowledge, they represent the first examples of 3D 4d−4f heterometallic coordination frameworks, in which the transition metal complexes bond to a 3D lanthanide carboxylate supramolecular framework with nanometer-sized channels built up from 2D wavelike layers. Compound 3 possesses an unusual 3D framework based on linkage of neodymium−carboxylate chains and silver(I) centers by inic ligands. The difference between both kinds of frameworks can be ascribed to the geometry effect of benzenedicarboxylate. Furthermore, the luminescent properties of 2 were studied.

Luminescent Lanthanide(III) Carboxylate−Phosphonates with Helical Tunnels

Hydrothermal reactions of lanthanide(III) salts with H4PMIDA (N-(phosphonomethyl)iminodiacetic acid) led to seven new isostructural lanthanide(III) carboxylate phosphonates, namely, Ln(HPMIDA)(H2O)2·H2O (Ln = Gd, 1; Tb, 2; Dy, 3; Y, 4; Er, 5; Yb, 6; Lu, 7). Their structures feature a novel 3D framework. The lanthanide(III) ion is eight-coordinated by a chelating HPMIDA in a tetradentate fashion (1 N and 3 O), one carboxylate oxygen and one phosphonate oxygen from two other HPMIDA anions, and two aqua ligands. The HPMIDA anion is hexadentate. It chelates with a Ln(III) ion tetradentatedly and also bridges with two other Ln(III) ions. The phosphonate group is singly protonated. One of the carboxylic groups is unidentate, whereas the other is bidentate bridging. Compound 2 exhibits very strong characteristic emission bands for the terbium(III) ion in the visible region under 380 nm excitation, with the Tb (5D0) lifetime for λex,em = 380 and 488 nm being about 1 ms. Compounds 1 and 5 display very broad ligand-centered emission bands in the blue light region.

Synthesis, crystal structure and properties of three new holmium 2-fluorobenzoato complexes

This paper reports three new holmium 2-fluorobenzoato (2-FBA) complexes with 1,10-phenanthroline (phen), 2,2′-bipydine (2,2′-bpy) and 4,4′-bipyridine, respectively. A rare and interesting structural feature of holmium 2-FBA complex containing phen is two non-equivalent binuclear molecules existed in an asymmetric unit, namely, [Ho(2-FBA) 3·phen·CH 3CH 2OH] 2 and [Ho(2-FBA) 3·phen] 2. The dimeric complex [Ho(2-FBA) 3·2,2′-bpy] 2 is a type of eight-coordinated lanthanide carboxylate complexes containing 2,2′-bpy. The {[Ho(2-FBA) 3·2H 2O]·(4,4′-bpy)} n is in one-dimensional polymeric structure, and the 3D supramolecular network structure is formed by the hydrogen bonds and π–π stacking interactions.

Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts

The well-defined coordination environment of trivalent [(C5Me5)2Ln]+ complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R2AlCl (R = Me, Et, iBu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R2AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C5Me5)2Sm(O2CC6H5)]2, but instead of forming a simple chloride complex like [(C5Me5)2SmCl]3, bimetallic lanthanide aluminum dichloro complexes (C5Me5)2Sm(μ-Cl)2AlR2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C5Me5)2Sm(THF)2 and R2AlCl. However, the analogous reaction between (C5Me5)2Sm(THF)2 and Et3Al gives (C5Me5)2Sm(THF)(μ-η2-Et)AlEt3, which contains the first Ln(III)−(η2-Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C5Me5)2Ln(μ-Cl)(μ-R)AlR2 complexes can be isolated, (C5Me5)2Y(μ-Cl)YCl(C5Me5)2 was reacted with R3Al. These reactions form [(C5Me5)2Y(μ-Cl)(μ-R)AlR2]x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C5Me5)2Y(μ-Cl)2AlR2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and iBu comparisons.

Syntheses, crystal structures, and luminescent properties of novel layered lanthanide sulfonate-phosphonates.

Hydrothermal reactions of lanthanide metal salts with MeN(CH(2)CO(2)H)(CH(2)PO(3)H(2)) (H(3)L) and 5-sulfoisophthalic acid monosodium salt (NaH(2)BTS) lead to four isomorphous lanthanide carboxylate-phosphonate-sulfonate hybrids, namely, Ln(H(2)L)(HBTS)(H(2)O)(2).H(2)O (Ln = La (1), Pr (2), Nd (3), Gd (4)). Their structures have been established by X-ray single-crystal diffraction. The interconnection of the lanthanide(III) ions by carboxylate-phosphonate ligands results in a 1D double chain; these double chains are further bridged by bidentate bridging carboxylate-sulfonate ligands to form a <011> layer. The luminescent properties of compounds 3 and 4 have also been studied.

Chloride Effects in Lanthanide Carboxylate Based Isoprene Polymerization

Chloride Effects in Lanthanide Carboxylate Based Isoprene Polymerization

Synthesis, structure and properties of a three-dimensional porous rare-earth carboxylate MIL-83(Eu): Eu2(O2C-C10H14-CO2)3

A new three-dimensional rare-earth(III) dicarboxylate, MIL-83(Eu) or Eu2(O2C-C10H14-CO2)3, has been obtained under hydrothermal conditions from aqueous mixtures of europium nitrate and 1,3-adamantanedicarboxylic acid. Its three-dimensional structure consists of chains built up from face-sharing nine-coordinated rare-earth(III) polyhedra connected by the 1,3-adamantanedicarboxylate linkers, delimiting anhydrous porous channels. This structure is understood by comparison with the already known hybrid rare-earth(III)carboxylates. The thermal behavior of the solid has been investigated using TGA and X-ray thermodiffractometry and shows that the title solid is stable up to 300 °C. Finally, the study of the luminescence properties of the yttrium(III) form of MIL-83(Y/Eu) doped with europium(III) reveals a significant red-emission upon VUV radiation.

The use of glassfibres coated with terbium doped sol–gel films in UV sensors

Since glassfibres are a common method for transport of information, this study examines the application of glassfibres in UV sensors. To this end, the glassfibres have been coated with a silica-xerogel doped with lanthanide carboxylate complexes, especially terbium picolinate (TbPic). Different pretreatments of the glassfibres have been tested in order to enhance the signal to background ratio of the terbium line emission of 545 nm wavelength. It has turned out that the signal to background ratio can be increased by a factor of nine by etching the surface of the glassfibre with concentrated hydrofluoric acid.

Dendritic lanthanide complexes and the effect of Lewis-acid encapsulation

The synthesis of complexes using terbium(III) ions and dendritic branches based on L-lysine building blocks is reported. These complexes are bound via predominantly electrostatic lanthanide–carboxylate interactions, and were characterised using a range of approaches. The ability of these Lewis-acidic complexes and terbium acetate to influence the regiochemical outcome of a Diels–Alder reaction was investigated, but they were found to have minimal effect. Interestingly, however, non-dendritic terbium(III) acetate was observed to remain bound to the product of the reaction, broadening its NMR spectrum, whilst the dendritic terbium complexes did not interact in this way. This indicates that the Lewis-acidic centre in the more highly functionalised dendritic derivatives may be inaccessible, either sterically or electronically, both to substrates and products of organic transformations.

Synthesis, Crystal Structure, and Photophysical and Magnetic Properties of Dimeric and Polymeric Lanthanide Complexes with Benzoic Acid and Its Derivatives

AbstractA new family of lanthanide carboxylate complexes with benzoic acid and its derivatives was synthesised and characterised. The structures of the complexes were established by X‐ray crystallography, which revealed that various chelating modes of the carboxylate ligands are present on the metal ion, resulting in the formation of dimeric and polymeric skeletons. The photophysical properties of the Eu and Tb complexes were studied: the complexes exhibited sensitised luminescence in the visible spectral region, but the luminescence intensities and lifetimes were very sensitive to quenching by the OH groups of methanol molecules. The solid‐state magnetic properties of the Gd and Tb complexes demonstrated the presence of weak antiferromagnetic exchange interactions at very low temperatures, caused by interaction between the neighbouring ions along the chain. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)

Rare-Earth Ziegler−Natta Catalysts: Carboxylate−Alkyl Interchange

Alkylated rare-earth-metal centers are definitely formed in “Mischkatalysatoren”: the homoleptic, tailor-made rare-earth carboxylate complexes {Ln(O2CC6H2iPr3-2,4,6)3}n (Ln = Y, La, Nd, Lu) react with trimethylaluminum to yield hexane-soluble monolanthanide complexes of the larger elements featuring a η2-coordinating tetraalkylaluminate ligand and a novel ancillary AlMe2-bridged bis(carboxylate) ligand. In the presence of AlMe2Cl, such alkylated derivatives transform isoprene to a high-cis polymer (>99%).

Syntheses, crystal structures and properties of two novel lanthanide–carboxylate polymeric complexes

Two novel lanthanide–carboxylate polymeric complexes containing nine-coordinate lanthanide metal centers, [Nd(H2btec)1/2(btec)1/2(H2O)]n (1), [Gd(Hbtec)]n (2), have been prepared by hydrothermal reaction of NdCl3·6H2O or Gd(NO3)3·6H2O with 1,2,4,5-benzenetetracarboxylic dianhydride. Complex 1 crystallizes in triclinic space group P, with a = 6.3822(5), b = 9.3323(7), c = 9.5201(7) Å, α = 88.422(2), β = 74.446(2), γ = 76.647(10)°, V = 531.13(7) Å3 and Z = 2. Complex 2 crystallizes in triclinic space group P, with a = 7.2325(7), b = 7.9946(8), c = 8.7833(9) Å, α = 65.4120(10), β = 86.272(2), γ = 84.377(2)°; V = 459.42(8) Å3 and Z = 2. The two complexes have high thermal stability and are stable up to 400 °C. Magnetic susceptibility measurements for 1 and 2 are consistent with the occurrence of antiferromagnetic interactions through carboxylate bridges.