Family Of Lanthanide Research Articles

Bright LanthanideIII Triboluminescence despite Low Photoluminescence, and Dual Triboluminescence and Mechano‐Responsive Photoluminescence (Advanced Optical Materials 9/2023)

Dancers on the cover symbolize the bright green and red triboluminescence (TL) of Tb(III) and Eu(III) complexes under mechanical stimuli (clapping), despite the great contrast between their photoluminescence (PL) efficiencies under UV illumination (spotlight). In article number 2203139, Yuichi Hirai and co-workers demonstrate the existence of direct lanthanide(III) excitation processes in TL, while ligand-mediated ones dominate the PL intensity. This work presents insights for fabricating a new family of lanthanide(III)-based functional mechanophores as well as providing the key to elucidate underlying mechanisms.

Family of Lanthanide–Manganese Heterometallic Metallacrowns: Syntheses, Structures, Magnetic Exchange, and Magnetocaloric Effects

The intermetallic magnetic interaction is a key role for exploring magneto-structure relationship. Herein, a series of Mn-based clusters featuring metallacrowns with the formulas [MnIIMn4III(L1)4(HL2)2(DMF)6]·4MeOH·3H2O (1), [GdMn4III(L1)4(OAc)4]·H4TEA·2MeOH·H2O (2), [Gd4Mn4III(L1)4(HL2)2(H2L1)4(OAc)4(μ3-OH)2(DMF)2(H2O)2]·4DMF·H2O·16MeOH·H3TEA (3), and [Gd6Mn4IIIMn2IV(L1)10(HL1)2(H2L1)4(DMF)4(H2O)4(MeOH)4]·4DMF·2MeOH·6H2O (4) (H3L1 = salicylhydroxamic acid, H2L2 = salicylic acid, MeOH = methanol, DMF = N,N-dimethylformamide, and H3TEA = triethylamine) were prepared using salicylhydroxamic acid as organic ligands. The structures of compounds 1–2, 3, and 4 featured 12-metallacrown-4, 16-metallacrown-6, and 28-metallacrown-10, respectively. Magnetic calculations showed that the obvious antiferromagnetic couplings of compounds 1–2 were mainly derived from MnIII···MnIII. For compound 3, the weak ferromagnetic couplings of GdIII···MnIII and MnIII···MnIII bridged through [M–O–N–M] manner were smaller than the antiferromagnetic couplings of GdIII···GdIII and GdIII···MnIII bridged by O atoms, resulting in the overall antiferromagnetic behavior. In compound 4, the weak ferromagnetic couplings of GdIII···MnIII/MnIII···MnIII/GdIII···MnIV/MnIII···MnIV bridged by the way of [M–O–N–M] were dominant. The abovementioned results revealed that the arrangement of metal ions displaying [M–N–O–M] is more likely to produce weak ferromagnetic coupling between metal ions, which is beneficial to the magnetocaloric effect (MCE). Meanwhile, compounds 3–4 showed considerable MCEs with a magnetic entropy change (−ΔSm) of 13.86 J kg–1 K–1 at 3.5 K, 7 T and 16.05 J kg–1 K–1 at 3 K, 7 T, respectively.

Compact ultrabroadband light-emitting diodes based on lanthanide-doped lead-free double perovskites

Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels. Herein, a family of lanthanide (Ln3+) ions was successfully incorporated into a Bi:Cs2AgInCl6 lead-free double-perovskite (DP) semiconductor, expanding the spectral range from visible (Vis) to near-infrared (NIR) and improving the photoluminescence quantum yield (PLQY). After multidoping with Nd, Yb, Er and Tm, Bi/Ln:Cs2AgInCl6 yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of ~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f–4f transitions of the Ln3+ dopants. Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes. To avoid adverse energy interactions between the various Ln3+ ions in a single DP host, a heterogeneous architecture was designed to spatially confine different Ln3+ dopants via a “DP-in-glass composite” (DiG) structure. This bottom-up strategy endowed the prepared Ln3+-doped DIG with a high PLQY of 40% (nearly three times as high as that of the multidoped DP) and superior long-term stability. Finally, a compact Vis–NIR ultrabroadband (400~2000 nm) light source was easily fabricated by coupling the DiG with a commercial UV LED chip, and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.

Interpenetrated Metal-Organic Frameworks with ftw Topology and Versatile Functions.

Through an "isoreticular expansion" strategy, a large number of highly porous zirconium-based metal-organic frameworks (Zr-MOFs) have been achieved using extended organic linkers in the past few years. However, interpenetrated Zr-MOFs with ftw topology have scarcely been reported, mainly owing to the used bulky tetratopic linkers that effectively prevent the network interpenetration. Here, we report a new family of zirconium and lanthanide (Ln) MOFs with ftw topology, constructed by hexanuclear Zr or Ln (Ln = Eu, Tb, Gd, Dy, Tm, Yb, Nd, and Er) clusters and a spirobifluorene-center tetracarboxylate linker. Our studies reveal that the isostructural Zr and Ln MOFs are all doubly interpenetrated with ultrahigh thermal and chemical stability. The observed unusual interpenetration can be attributed to the specific geometry of the spirobifluorene-center tetratopic linker. Gas adsorption studies show that the interpenetrated Zr-MOF is still highly porous and exhibits high performance for CO2 storage, which can be attributed to the strong CO2 binding environment contributed by the reduced pore size. In addition, the presented MOFs display strong characteristic luminescence in the UV-vis-NIR region. Moreover, the incorporation of the spiro-center linker into the framework can efficiently produce two-photon-excited photoluminescence with a large action cross-section value, which also benefited from the high packing density of the nonlinear optical chromophore linker in the interpenetrated structure.

Synthesis, Thermal, Structural Analyses, and Photoluminescent Properties of a New Family of Malonate-Containing Lanthanide(III) Coordination Polymers.

Five new Lanthanide(III) complexes of malonic acid (HOOC-CH2-COOH); {[Gd(C3H2O4)(H2O)4]·NO3}n (1), {[Tb(C3H2O4)(H2O)4]·NO3}n (2), {[Ho(C3H2O4)(H2O)4]·NO3}n (3), [Er(C3H2O4)(C3H3O4)(H2O)2]n (4), and {[Eu2(C3H2O4)2(C3H3O4)2(H2O)6]·4H2O}n (5) were synthesized and characterized by elemental, infrared spectral, and thermal analyses. The structures of compounds 1–5 were determined by single crystal X-ray diffraction technique. The X-ray analysis reveals that compounds 1, 2, and 3 are isostructural and crystallized in the orthorhombic space group Pmn21. The lanthanide(III) ions are coordinated by four carboxylate and four water oxygen atoms adopting a distorted square antiprism geometry. The LnO8 square antiprisms are linked into infinite layers by malonate (C3H2) dianions sandwiching sheets of nitrate counter ions. Compound 4 contains ErO8 square antiprisms linked into a two-dimensional network by hydrogen malonate (C3H3) anions and malonate dianions. The europium complex, 5 is dinuclear having the two europium(III) ions (Eu1 and Eu2) bridged by carboxylate groups of hydrogen malonate ligands. The europium ions in 5 are nine-coordinate and exhibit a distorted monocapped square antiprism geometry. All the structures are consolidated by O–H⋯ O hydrogen bonds. The photoluminescence spectra of 1–5 exhibit characteristic emissions in the visible region. The IR spectra and thermal data are consistent with the structural results. The room-temperature effective magnetic moments for 1–4 are in good agreement with those expected for the free ions, while the data for 5 indicates that low-lying excited states contribute to the observed moment. The compound 1 was further subjected to quantum computational calculations to explore its optoelectronic properties including; density of states (DOS), dielectric function, refractive index, extinction coefficient, and absorption spectrum, to highlight the possible applications of such materials in the optoelectronics.

Structural diversities and gas adsorption properties of a family of rod-packing lanthanide–organic frameworks based on cyclotriphosphazene-functionalized hexacarboxylate derivatives

A family of Ln-MOFs constructed from flexible hexacarboxylate derivatives exhibit substituent-driven structural diversity, and the methoxy-modified one displays the potential for natural gas purification.

Slow magnetic relaxation and luminescence properties in lanthanide(iii)/anil complexes.

The initial use of anils, i.e. bidentate Schiff bases derived from the condensation of anilines with salicylaldehyde or its derivatives, in 4f-metal chemistry is described. The 1 : 1 reactions between Ln(NO3)3·xH2O (Ln = lanthanide) or Y(NO3)3·6H2O and N-(5-bromosalicylidene)aniline (5BrsalanH) in MeCN has provided access to complexes [Ln(NO3)3(5BrsalanH)2(H2O)]·MeCN (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) and [Y(NO3)3(5BrsalanH)2(H2O)]·MeCN, respectively, in good yields. The structures of the isomorphous complexes with Ln = Pr(1·MeCN), Sm(3·MeCN), Gd(5·MeCN), Dy(7·MeCN) and Er(9·MeCN) have been determined by single-crystal X-ray crystallography. The other complexes were proven to be isostructural with the fully structurally characterized compounds based on elemental analyses, IR spectra, unit cell determinations and powder X-ray patterns. The 9-coordinate LnIII centre in the [Ln(NO3)3(5BrsalanH)2(H2O)] molecules is bound to six oxygen atoms from the three bidentate chelating nitrato groups, two oxygen atoms that belong to the organic ligands and one oxygen atom from the aquo ligand. The 5BrsalanH molecules behave as monodentate O-donors; the acidic H atom is clearly located on the imino N atom and thus the formally neutral ligands adopt an extremely rare coordination mode participating in the zwitterionic form. The coordination polyhedra defined by the nine donor atoms around the LnIII centres are best described as spherical capped square antiprisms. Various intermolecular interactions build the crystal structures and Hirshfeld surface analysis was applied to evaluate the magnitude of interactions between the molecules. Solid-state IR and UV/VIS data are discussed in terms of structural features. 1H NMR data prove that the diamagnetic [Y(NO3)3(5BrsalanH)2(H2O)] complex decomposes in DMSO. Combined dc and ac magnetic susceptibility, as well as magnetization data for 7 suggest that this complex shows field-induced slow magnetic relaxation. Two magnetization relaxation processes are evident. The fit to the Arrhenius law has been performed using the 6.5-8.5 K ac data, affording an effective barrier for the magnetization reversal of 27 cm-1. Cole-Cole plot analysis in the temperature range in which the Orbach relaxation process is assumed, reveals a narrow distribution of relaxation times. The solid Dy(iii) complex 7 emits green light at 338 nm, the emission being ligand-centered. The perspectives of the present, first results in the lanthanide(iii)-anil chemistry are critically discussed.

Photoluminescence and magnetic analysis of a family of lanthanide(iii) complexes based on diclofenac

A family of ten isostructural complexes based on the diclofenac ligand exhibiting interesting magnetic and luminescence properties has been prepared.

Heptanuclear lanthanide [Ln7] clusters: from blue-emitting solution-stable complexes to hybrid clusters.

The use of LH3 (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) and aibH (2-amino-isobutyric acid) in 4f chemistry has led to the isolation of eight new isostructural lanthanide complexes. More specifically, the reaction of the corresponding lanthanide nitrate salt with LH3 and aibH in MeOH, under solvothermal conditions in the presence of NEt3, led to the isolation and characterization of seven complexes with the general formulae [Ln(III)7(OH)2(L')9(aib)]·4MeOH (Ln = Gd, ·4MeOH; Tb, ·4MeOH; Dy, ·4MeOH; Ho, ·4MeOH; Er, ·4MeOH; Tm, ·4MeOH; Yb, ·4MeOH L' = the dianion of the Schiff base between naphthalene aldehyde and 2-amino-isobutyric acid). Furthermore, the isostructural Y(III) analogue, cluster [Y(III)7(OH)2(L')9(aib)]·4MeOH (·4MeOH), was synthesized in a similar manner to . The structure of all eight clusters describes a distorted [M(III)6] octahedron which encapsulates a seventh M(III) ion in an off-centre fashion. Dc magnetic susceptibility studies in the 5-300 K range for complexes reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters as evidenced by the negative Weiss constant, θ, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the [Dy(III)7] analogue (·4MeOH), suggesting potential single molecule magnetism character. Furthermore, for complex , simulation of its dc magnetic susceptibility data yielded very weak antiferromagnetic interactions within the metallic centres. Solid-state emission studies for all clusters display ligand-based emission, while extended 1D and 2D NMR studies for ·4MeOH reveal that the species retain their structural integrity in solution. In addition, TGA measurements for , and revealed excellent thermal stability up to 340 °C for the clusters.

A family of 3D lanthanide–organic frameworks constructed from parallelogram secondary building units: synthesis, structures and properties

A family of lanthanide–organic frameworks, {Ln2(pyip)(ox)2.5(H2O)5}n (Ln = La (1), Pr (2), Sm (3), Eu (4), Gd (5), Tb (6), Dy (7)) has been synthesized based on mixed bridging ligands, H2pyip and oxalate anion (H2pyip = 5-(4-pyridyl)-isophthalic acid, H2ox = oxalic acid) and characterized by elemental analysis, Fourier transform infrared spectroscopy, steady state and time-resolved luminescence spectroscopy, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. The single-crystal X-ray diffraction analysis results show that complexes 1–7 are isostructural. They crystallize in the same P21/c space group and exhibit a (3,4)-connected {42·6·82·10}{82·10} topology, being a 2-nodal net topology. The luminescence properties of 3, 4, 6, and 7 were investigated and related to the structural properties. The magnetic studies reveal that strong ferromagnetic coupling exists in compound 6.

Synthesis and structure of a new family of 3d–4f heterometallic compounds Rb7LnFe6O2(PO4)8 (Ln=Sm, Eu, Gd, Dy): Magnetic properties of the Sm-, Gd-, Dy-derivatives

A new family of mixed lanthanide(III) and iron(III) oxo-phosphate phases, Rb7LnFe6O2(PO4)8 (Ln=Sm 1, Eu 2, Gd 3, Dy 4), was isolated by using a high-temperature, solid-state method in molten-salt media. The X-ray single-crystal structure analysis shows that these isomorphic derivatives crystallize in a triclinic space group P–1 (no. 2); Z=1. The 3-D framework of these 3d–4f oxo-phosphates are comprised of LnO6 octahedral, FeO5 trigonal bipyramidal (tbp), and μ3-oxo [Fe4O18] tetrameric units interconnected through PO4 tetrahedra. The preliminary results of the temperature-dependent magnetic susceptibility measurements for selected compounds (1, 3, 4) reveal antiferromagnetic-like behavior. 1 shows a weak antiferromagnetric ordering at TN=∼7K while others show little evidence of long-range magnetic order down to 2K. All three compounds have measured magnetic moments significantly smaller than the expected values.

Structure, bonding, electronic and energy aspects of a new family of early lanthanide (La, Ce and Nd) complexes with phosphoric triamides: Insights from experimental and DFT studies

A new family of isostructural early lanthanide(III) complexes (LnXPA) of the general formula Ln(XPA)(2)Cl(3)(solv)(2), where Ln = La, Ce and Nd, XPA = (4-X-C(6)H(4)NH)P(O)(NC(4)H(8)O)(2), X = H, F, Cl and Br, and solv = H(2)O and CH(3)OH, is introduced. X-ray crystallography shows that the replacement of the coordinated water by a methanol molecule may reduce the symmetry level of the unit cell from the orthorhombic crystal system and the space group Fdd2 to monoclinic and C2/c. DFT calculations, at B3LYP, PBE and B3PW91 levels, have been carried out to get a better insight into the structural, electronic and energy aspects of the compounds. The large cation attraction energy (-ΔE) values in the range 269-273 kcal mol(-1), at the B3PW91/ECP/6-311+G** level for the model complexes XPA-La(3+) with stoichiometry 1 : 1, represent new ligands XPA as efficient complexant agents for lanthanides. The electronic nature of para substituent X has no significant effect on the Ln-ligand bonding and cation affinity of the ligands XPA. The results of atoms in molecules (AIM) analysis reveal a partial covalent contribution of the Ln-ligand interaction for the models XPA-La(3+) in the absence of counterions and coordinated solvents. In the real complexes LnXPA, a closed-shell Ln-ligand interaction is established. Increasing the charge difference between nitrogen and phosphorus atoms (by ~0.06 e) associated with a weakening of the Lp(O(P))→σ*(P-N) electronic delocalization (Lp(O(P)) being the lone pair of the phosphoryl oxygen atom) may lead to an increase in partial multiple bond character of the P-N bonds in coordinated ligands, agreeing with the increase in ν(P-N) and (2)J(PH) coupling constant values. The changes in electron density (ρ) and electronic energy density (H(r)) values confirm these structural reorganizations upon complexation.

Ultrasensitive sorption behavior of isostructural lanthanide–organic frameworks induced by lanthanide contraction

Reactions of lanthanide nitrate and the trigonal-planar ligand 1,3,5-benzenetrisbenzoic acid (H3BTB) gave rise to a family of lanthanide–organic frameworks (LOFs) formulated as Ln(BTB)(H2O), where Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb. Single-crystal X-ray diffraction (XRD) analysis of Pr-LOF reveals a three-dimensional network with an ultramicroporous structure. Powder XRD and thermogravimetric analyses show that these LOFs are isostructural and can firmly stabilize up to 550 °C. Influenced by the opposite effects of ionic radius and molecular weight from La(III)–Yb(III), the related LOFs with the highest uptake of CO2 and CH4 happen to be Nd-LOF and Sm-LOF, respectively. Moreover, the isotherms of N2 at 77 K and benzene vapor at 298 K further evidence that lanthanide contraction greatly affects the adsorption performance of the resulting materials, bringing about stepwise and hysteretic sorption behavior for La-LOF to Pr-LOF but type I isotherms for the rest of the LOFs. This work represents the first systematic study of a family of lanthanide-based metal–organic frameworks with ultrasensitive sorption behavior induced by the lanthanide contraction.

A family of lanthanide–nitronyl nitroxide complexes: syntheses, crystal structures and magnetic properties

Seven Ln(III) complexes based on a novel nitronyl nitroxide radical have been synthesized and characterized structurally and magnetically: [Ln(hfac)3(NITNapOMe)2] (Ln = Pr(1), Gd(2), Tb(3), Dy(4), Ho(5), Er(6), Tm(7); hfac = hexafluoroacetylacetonate; NITNapOMe = 2-6′-methoxy-2′-naphthyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide). The single-crystal analyses show that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ions are eight coordinated by three hfac molecules and two NITNapOMe radicals. The variable-temperature magnetic susceptibility studies reveal the ferromagnetic interactions between Ln(III) ion and radicals in complexes 3, 4, and 7 and antiferromagnetic interactions in complexes 1, 2, 5, and 6.

General synthesis and characterization of a family of layered lanthanide (Pr, Nd, Sm, Eu, and Gd) hydroxide nanowires

A family of layered lanthanide (Pr, Nd, Sm, Eu, and Gd) hydroxide nanowires (NWs) has been synthesized via a hydrothermal route. These NWs are ∼8 nm in diameter and a few micrometres in length. The obtained Eu- and Gd-based layered hydroxide NWs consist of layered structure with two interlayer spacings. The effects of hydrothermal temperature and time on the transition of the layered structure were investigated. Photoluminescence of the Eu-based layered hydroxide NWs was also studied. These layered lanthanide hydroxide NWs combine the advantages of lanthanide and layered hydroxides, which will expand the inorganic layered materials and can be expected to be used as building blocks for further fabrication of functional nanostructures.

A novel family of 3D photoluminescent lanthanide–bta–flexible MOFs constructed from 1,2,4,5-benzenetetracarboxylic acid and different spanning of dicarboxylate acid ligands

By using 1,2,4,5-benzenetetracarboxylic acid as a rigid polycarboxylate metal linker and three types of flexible dicarboxylate ligands containing different –CH2– spacers as the second linker, a novel family of lanthanide MOFs (1–12) with three kinds of 3D framework structures, namely, [Ln2(ox)(bta)(H2O)4](Ln = Eu (1), Tb (2), Dy (3), Ho (4); H2ox = oxalic acid; H4bta = 1,2,4,5-benzenetetracarboxylic acid), [Ln2(glu)(bta)(H2O)4]·H2O (Ln = Tb (5), Eu (6), Dy (7), Ho (8); H2glu = glutaric acid), [Ln2(ad)(bta)(H2O)2] (Tb (9), Eu (10), Dy (11), Er (12); H2ad = adipic acid), have been synthesized under hydrothermal conditions. All coordination polymers were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that the networks of the twelve polymers exhibit a variety of coordination modes to metal centers and all have three dimensional structures. The photoluminescent properties for the polymers 1–3, 5–7 and 9–11 were examined by using luminescence spectra and the analysis results indicate that different spanning flexible linkers have different influence on the characteristic photoluminescence when the rigid linker is the same.

Crystal structures, luminescent properties and thermal decomposition kinetics of lanthanide complexes with 2-chloro-4-fluorobenzoic acid and 2,2′-bipyridine

A new family of lanthanide with the general formula [Ln(2-Cl-4-FBA) 3bipy] 2 (Ln = Nd( 1), Sm( 2), Eu( 3), and Ho( 4); 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate; bipy = 2,2′-bipyridine) were synthesized and characterized by elemental analysis, molar conductance, and infrared, ultraviolet and luminescent spectroscopy, single-crystal X-ray diffraction, thermogravimetry and different thermogravimetry (TG–DTG) techniques. These compounds are iso-structural and the lanthanide ions are all nine coordinated via two bidentate chelating, two bidentate bridging and two bidentate chelating-bridging modes. Under excitation, the europium complex exhibited characteristic red fluorescence of Eu 3+ ion at room temperature. The non-isothermal kinetics was investigated by using NL-INT and Popescu methods. The mechanism functions of the first decomposition step of the title complexes were determined. Meanwhile, the thermodynamic parameters (Δ G ≠, Δ H ≠ and Δ S ≠ ) were also calculated.

A Series of Lanthanide−Organic Frameworks Based on 2-Propyl-1H-imidazole-4,5-dicarboxylate and Oxalate: Syntheses, Structures, Luminescence, and Magnetic Properties

A family of self-assembly lanthanide−organic coordination polymers with both rigid and flexible ligands formulated as {[Ln2(Hpimda)2(μ4-C2O4)·2H2O]·4H2O}n (Ln = Sm (1), Eu (2), Tb (3), Dy (4), Ho (5), Er (6), H3pimda = 2-propyl-1H-imidazole-4,5-dicarboxylic acid) has been synthesized from the reactions of H3pimda with trivalent lanthanide salts in the presence of oxalate as coligand. X-ray diffraction analysis reveals that these complexes are isomorphous and isostructural, and each forms a novel three-dimensional (3D) frameworks structure, in which the metalloligands' two-dimensional (2D) networks were constructed from the lanthanide ion, 2-propyl-imidazole-dicarboxylate as well as oxalate ligands, and the oxalate further acts as a pillar to link the [Ln(Pimda)(oxo)] 2D grids to generate the 3D open frameworks, leaving one-dimensional channels, which are occupied by water clusters displaying an intricate array. The luminescence emission spectra of the complexes vary depending on which lanthanide ion is pr...

Hydrothermal synthesis and structural characterization of a family of lanthanide tartrates: [Ln 2(C 4H 4O 6) 3(H 2O) 3]·1.5H 2O (Ln = La, Ce, Pr, Nd, Sm)

Coordination polymers containing lanthanides with tartaric acid [Ln 2(C 4H 4O 6) 3(H 2O) 3]·1.5H 2O (Ln = La, Ce, Pr, Nd, Sm and C 4H 4O 6 = d(−) or l(+) tartrate anion) have been synthesized using hydrothermal techniques and characterized by single crystal X-ray diffraction. The compounds are all isotypic with a monoclinic crystal system in the P2 1/ n space group. The asymmetric units of coordination polymers contain two metal centers having different coordination environments. One metal is bonded to four tartrate groups having three d and one l isomers (or three l and one d isomers), whereas the other metal is bonded to five tartrate groups having two d and three l isomers (or two l and three d isomers). Each trivalent metal center is coordinated to nine oxygen atoms that originate from carboxylate and hydroxyl groups of the tartrate anions and water molecules. These new polymers have three-dimensional structures containing open channels that are occupied by non-coordinating water molecules. Thermogravimetric and differential thermal analyses and adsorption of nitrogen have also been studied for these compounds.

A new family of luminescent lanthanide based coordination polymers

Reaction in water between a lanthanide ion (Ln = Sm–Dy) and the sodium salt of isophthalic acid leads to a new family of lanthanide-based coordination polymers. The crystal structure has been solved on the basis of the Gd containing compound. The iso-structurality of the other compounds has been assumed on the basis of powder X-ray diffraction diagrams. These compounds of general formula Ln2(OH)(C8H4O4)2(C8H5O4)(H2O)8·6H2O crystallize in the monoclinic system, space group P21/a (no. 14) with a = 17.4249(2) Å, b = 10.9148(1) Å, c = 20.7216(2) Å, β = 113.1694(4)° and Z = 4. This crystal structure is 1-D. Chains are bound to each other by hydrogen bonds. The thermal stability of these compounds is described and discussed as well as luminescent properties of the coordination polymers involving luminescent rare earth ions.