Polymeric Lanthanide Complexes Research Articles

Dinuclear mono-bridged or polymeric lanthanide complexes from one ligand: structural transformation and chiral induction.

We designed and synthesized a semi-rigid bis-tridentate ligand L which could undergo a trans-to-cis conformational transition when coordinated onto lanthanum ions through the rotation of the single bond on the central terphenyl bridge. By adjusting the metal/ligand ratio, a single-ligand bridged dinuclear complex La2L3 and an infinitely extending two-dimensional layered metal organic polymer (La2L2)n can be obtained. Through the induction of the chiral auxiliary ligand GR/S, these two achiral assemblies could both be transformed into the chiral mononuclear three-component complex LaLGR/S. In addition, we also realized a linear ee sensing for the auxiliary ligand by induced circular dichroism.

Preparation of polymer–rare earth complexes based on Schiff-base-containing salicylic aldehyde groups attached to the polymer and their fluorescence emission properties

AbstractIn this study, the salicylaldehyde hydrazone was bonded onto the side chains of poly (styrene-co-butyl acrylate), firstly obtaining a series of novel Schiff base-functionalized polymers. and using the base-containing polymers as macromolecular ligands through further reaction with EuCl3/YbCl3·6H2O, a series of polymer-rare earth complexes based on Eu(III)/Yb(III) ion were successfully prepared. The structures of the schiff base-containing polymers and their corresponding complexes were characterized by means of infrared spectra and UV spectra. The thermal properties of the functionalized polymers and complexes were investigated by TGA, and the fluorescence properties of the complexes were also researched by fluorescence spectrum. The experimental results show that the complexes have fine thermal stability likely because of the bidentate chelate effect of base-containing polymer and the conjugative effect of salicylaldehyde hydrazone group on the side chain of poly (styrene-co-butyl acrylate). More important, the salicylaldehyde hydrazone group on the side chains of poly(styrene-co-butyl acrylate) can efficaciously sensitize the fluorescence emission of the center ion due to effective intramolecular energy transfer. All the Eu(III)/Yb(III) complexes exhibit characteristic photoluminescence peaks in the visible region. The fluorescence excitation spectra of the complexes were obtained by monitoring the emission of Eu3+/Yb3+ ion at 497 nm, and the peak at 433 nm was found to be the optimal excitation peak. The concentration of salicylaldehyde hydrazone group was changed gradually with the variation of the molar ratio between the butyl acrylate and styrene (1:0.5; 1:1; 1:1.5; 1:2; 1:2.5), and the differences in their fluorescent intensity were followed, and the fluorescence intensity was very weak when the molar ratio of the butyl acrylate to styrene is equal to 1:2.5, while the fluorescence intensity reached a maximum value in the molar ratio of 1:1.

Preparation of two novel Schiff base polymers and their Eu (III)/Yb (III) complexes

A series of novel Schiff base photosensitive polymers with coordination property were synthesized through a condensation reaction. Then using the Schiff base photosensitive polymers as macromolecular ligands, a series of polymer rare-earth complexes were prepared through a coordination reaction. The structure of the polymer and their corresponding complex was performed by means of Fourier transform infrared and ultraviolet spectroscopy; the fluorescence properties of the complex were mainly investigated by fluorescence spectroscopy, and the thermal property was investigated by differential scanning calorimetry and thermogravimetric analysis. The luminescence properties of the europium (Eu) (III)/ytterbium (Yb) (III) complex in dimethylformamide solutions were investigated. The experimental results show that the complexes have fine thermal stability and all the europium (III)/ytterbium (III) complexes exhibit characteristic photoluminescence peaks in the visible region and the results indicate that the complexes are promising in the field of light-emitting materials and can be further mixed with a suitable polymer to form functional rare-earth polymers.

Preparation and luminescent properties of the novel polymer-rare earth complexes composed of Poly(ethylene-co-acrylic acid) and Europium ions

A series of novel polymer-rare earth complexes with Eu3+ ions have been synthesized and investigated successfully, including the binary complexes containing the single ligand poly(ethylene-co-acrylic acid) (EAA) and the ternary complexes using 1,10-phenanthroline (phen), dibenzoylmethane (DBM) or thenoyltrifluoroacetone (TTA) as the second ligand. Their structures have been characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis and X-ray diffraction (XRD), which confirm that both EAA and small molecules participate in the coordination reaction with rare earth ions, and they can disperse homogeneously in the polymer matrixes. Both ultraviolet–visible (UV–vis) absorption and photoluminescence tests for the complexes have been recorded. The relationship between fluorescence intensity of polymer-rare earth complexes and the quantity of ligand EAA has been studied and discussed. The films casted from the complexes solution can emit strong characteristic red light under UV light excitation. All these results suggest that the complexes possess potential application as luminescent materials.

Synthesis and photoluminescence properties of novel Schiff base type polymer-rare earth complexes containing furfural-based bidentate Schiff base ligands

Luminescent polymer-rare earth complexes are an important class of photoluminescence and electroluminescence materials. Via molecular design, two furfural-based bidentate Schiff base ligands, furfural-aniline (FA) type ligand and furfural-cyclohexylamine (FC) type ligand, were bonded on the side chains of polysulfone (PSF), respectively, forming two functionalized macromolecules, PSF-FA and PSF-FC. And then through respective coordination reactions of the two functionalized macromolecules with Eu(Ⅲ) ion and Tb(Ⅲ) ion, novel luminescent binary and ternary (with 1,10-phenanthroline as the second ligand) polymer-rare earth complexes were synthesized. For these complexes, on basis of the characterization of their chemical structures, they photoluminescence properties were main researched, and the relationship between their luminescent properties and structures was explored. The experimental results show that the complexes coming from PSF-FA and Eu(Ⅲ) ion including binary and ternary complexes emit strong red luminescence, indicating that the bonded bidentate Schiff base ligand FA can sensitize the fluorescence emission of Eu(III) ion. While the complexes coming from PSF-FC and Tb(Ⅲ) ion produce green luminescence, displaying that the bonded bidentate Schiff base ligand FC can sensitize the fluorescence emission of Tb(Ⅲ) ion. The fluorescence emission intensities of the ternary complexes were stronger than that of binary complexes, reflecting the important effect of the second ligand. The fluorescence emission of the solid film of complexes is much stronger than that of the solutions of complexes. Besides, by comparison, it is found that the furfural (as a heteroaromatic compound)-based Schiff base type polymer-rare earth complexes have stronger fluorescence emission and higher energy transfer efficiency than salicylaldehyde (as a common aromatic compound)-based Schiff base type polymer-rare earth complexes.

Synthesis and characterization of two novel Schiff base type macromolecular ligands and preliminary research on luminescent property of polymer-rare earth complexes

Luminescent polymer-rare earth complexes are a class of functional materials, and bonding-type polymer-rare earth complexes is one important kind of such material. In this work, by molecular design and through polymer reactions, two types of bidentate Schiff base groups, benzaldehyde/ortho-aminophenol (BAOA) type and benzaldehyde/glutamic acid (BAGL) type groups, were synchronously synthesized and bonded on the side chain of polysulfone (PSF), respectively, and two new Schiff base type macromolecular ligands, PSF-BAOA and PSF-BAGL, were obtained. Then through coordination reactions, the luminescent polymer-rare earth complexes with different chemical structures were prepared. The synthesis and characterization of PSF-BAOA and PSF-BAGL were taken as the emphases of this study. The effects of main factors on the synthesis of the macromolecular ligands of PSF-BAOA and PSF-BAGL were fully researched, and their structures were fully characterized by FTIR and 1H-NMR. The luminescent properties of the prepared polymer-rare earth complexes were preliminarily discussed. The experimental results show that the Friedel-Crafts alkylation reaction of PSF with 4-(chloromethyl)benzaldehyde (CMBA) as the first step of the polymer reaction process can be smoothly carried out so that benzaldehyde (BA) as a group can be effectively bonded on the side chain of PSF, resulting in the modified polysulfone, PSF-BA. The appropriate solvent is N,N-dimethylacetamide (DMAC) with stronger polarity and suitable temperature is 70 °C. The subsequent Schiff reaction of PSF-BA with ortho-aminophenol (OAP) or glutamic acid (GLA) as the second step of the polymer reaction process can be easily carried out, successfully getting two macromolecular ligands, PSF-BAOA and PSF-BAGL. The complex of PSF-BAOA and Eu(III) ion produces strong red luminescence, whereas the complex of PSF-BAGL and Tb(III) ion exhibits strong green emission.

Effects of structures of bidentate Schiff base type bonded-ligands derived from benzaldehyde on the photoluminescence performance of polymer-rare earth complexes.

Two kinds of bidentate Schiff base ligands derived from benzaldehyde, benzaldehyde/m-aminophenol (BAMA) type and benzaldehyde/glutamic acid (BAGL) type ligands, were synchronously synthesized and bonded on the backbone of polysulfone (PSF) through molecular design and by polymer reactions, and two functional polymers, PSF-BAMA and PSF-BAGL, were obtained. Then two series of novel luminescent Schiff base-type polymer-rare earth complexes were prepared via coordination reactions. In this work, the effects of the structures of the bonded ligands on the photoluminescence performance of the complexes were investigated in detail, and for the different photophysical properties of the prepared complexes, relevant theoretical explanations were given. The experimental results show that the bonded ligand BAMA can strongly sensitize the fluorescence emission of Eu(iii) ions, and the binary complex PSF-(BAMA)3-Eu(iii) emits strong red fluorescence under UV light. The reason for this lies in the fact that a larger conjugate π-bond system is contained in the structure of BAMA, and so the triplet state of BAMA can be matched with the resonant energy level of the Eu(iii) ion. While the bonded ligand BAGL can effectively sensitize the fluorescence emission of Tb(iii) ions, the binary complex PSF-(BAGL)3-Tb(iii) exhibits very strong green fluorescence under UV light. The reason is that a smaller conjugate π-bond system is contained in the structure of BAGL and there is a good energy level matching between the triplet state of BAGL and the resonant energy level of the Tb(iii) ion. The fluorescence intensities of the two ternary complexes, PSF-(BAMA)3-Eu(iii)-(Phen)1 (phenanthroline, Phen) and PSF-(BAGL)3-Tb(iii)-(Phen)1, are much stronger than that of the corresponding binary complex because Phen as the second ligand has two effects, the effect of synergistic coordination with the first ligand and the effect of replacing the coordinated water around the central ion, and it has been confirmed by fluorescence spectroscopy and thermogravimetric analysis.

Synthesis and luminescent properties of a novel green-emitting Tb (Ⅲ) complex based on amino-modified fluorine silicone oil and isophorone diisocyanate

The novel luminescent polymer-rare earth complexes, denoted as (PFSi-IPDI)-Tb(Ⅲ)-Phen, have been successfully synthesized and can be made into flexible films. Amino-modified fluorine silicone oil-isophorone diisocyanate (PFSi-IPDI) was used as the host macromolecular ligand, and 1, 10-Phenanthroline (Phen) as the secondary small-molecular co-ligand. The luminescent lanthanide complexes were characterized by fourier transform infrared (FITR), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The luminescent properties were investigated through photoluminescence excitation (PLE) and emission (PL) spectroscopy. FTIR analysis verifies the successful preparation and integration of PFSi-IPDI to Tb3+. The comparatively uniform morphological structure can be observed in the images of SEM. The polymer-rare earth complexes display the typical luminescence emission peaks under the excitation wavelength of 330 nm. From the decay curve, the short lifetime (about 0.89 ms) is observed for (PFSi-IPDI)-Tb(Ⅲ)-Phen (0.6 mol/L). Moreover, these luminescent polymer-rare earth complexes possess superior thermal stability (T5 > 195 °C). All the interesting results suggest the potential application of the luminescent polymer-rare earth complexes in green-emitting luminescent materials under high temperature.

Synthesis and luminescence properties of polymer-rare earth complexes containing salicylaldehyde-type bidentate Schiff base ligand.

Using molecular design and polymer reactions, two types of bidentate Schiff base ligands, salicylaldehyde-aniline (SAN) and salicylaldehyde-cyclohexylamine (SCA), were synchronously synthesized and bonded onto the side chain of polysulfone (PSF), giving two bidentate Schiff base ligand-functionalized PSFs, PSF-SAN and PSF-SCA, referred to as macromolecular ligands. Following coordination reactions between the macromolecular ligands and Eu(III) and Tb(III) ions (the reaction occurred between the bonded ligands SAN or SCA and the lanthanide ion), two series of luminescent polymer-rare earth complexes, PSF-SAN-Eu(III) and PSF-SCA-Tb(III), were obtained. The two macromolecular ligands were fully characterized by Fourier transform infrared (FTIR), 1 H NMR and UV absorption spectroscopy, and the prepared complexes were also characterized by FTIR, UV absorption spectroscopy and thermo-gravity analysis. On this basis, the photoluminescence properties of these complexes and the relationships between their structure and luminescence were investigated in depth. The results show that the bonded bidentate Schiff base ligands, SAN and SCA, can effectively sensitize the fluorescence emission of Eu(III) and Tb(III) ions, respectively. PSF-SAN-Eu(III) series complexes, namely the binary complex PSF-(SAN)3 -Eu(III) and the ternary complex PSF-(SAN)3 -Eu(III)-(Phen)1 (Phen is the small-molecule ligand 1,10-phenanthroline), produce strong red luminescence, suggesting that the triplet state energy level of SAN is lower and well matched with the resonant energy level of the Eu(III) ion. By contrast, PSF-SAN-Eu(III) series complexes, namely the binary complex PSF-(SCA)3 -Tb(III) and the ternary complex PSF-(SCA)3 -Tb(III)-(Phen)1 , display strong green luminescence, suggesting that the triplet state energy level of SCA is higher and is well matched with the resonant energy level of Tb(III).

Modifying polysulfone into a bidentate Schiff base type macromolecular ligand and study on photoluminescence property of polymer–rare earth complexes of Eu(III) and Tb(III)

Chloromethylated polysulfone (CMPSF) was directly transformed into aldehyde (AL) group-functionalized polymer via Kornblum reaction, and then polysulfone was modified to a bidentate Schiff base (BS) type macromolecular ligand, PSF-ASB, via Schiff base reaction with 3-aminopyridine as reagent. Afterward, luminescent binary and ternary polymer-rare earth complexes, PSF-(ASB)3-Eu (III) and PSF-(ASB)3-Eu(III)-(Phen)1 (o-phenanthroline, Phen), were prepared. The macromolecular ligand PSF-ASB and the complexes were fully characterized by FTIR, 1H-NMR, UV spectroscopy and TGA. The photoluminescence properties and mechanisms of the complexes were investigated in depth. The experimental results show that the macromolecular ligand PSF-ASB itself emits strong fluorescence. However, after coordinating to Eu(III) ion, its fluorescence intensity weakens remarkably, implying that there occurs an intramolecular energy transfer. The complexes of Eu(III) ion exhibit stronger characteristic fluorescence emission of Eu(III) ion, whereas the complex of Tb(III) ion has no photoluminescence property, indicating that the bonded ligand ASB can effectively sensitize the fluorescence emission of Eu(III) ion and suggesting that the triplet state energy of the bonded ligand ASB is well matched with the resonant state level of Eu(III) ion. More importantly, relative to general polymer-rare earth complexes, for these luminescent polymer-rare earth complexes prepared in this study, the backbone of the macromolecular ligand PSF-ASB also takes part in the sensitization towards Eu(III) ion because of that half of aryl rings of a greater π bond conjugate system of ASB comes from PSF skeleton, displaying a great difference with other luminescent polymer-rare earth complexes.

Effect of substituent groups with two types on benzene ring on photoluminescence property of complexes of benzoic acid—Functionalized polystyrene with Eu(III) Ion

Abstract Two benzoic acid derivatives, methoxybenzoic acid (MOBA) and formylbenzoic acid (FBA), on whose benzene ring, an electron-donating substituent group (methoxy group) and an electron-withdrawing substituent group (formyl group) exist, respectively, were bonded onto the side chains of polystyrene (PS) through polymer reactions, obtaining two benzoic acid derivative-functionalized PSs, PS-MOBA and PS-FBA. The two macromolecule ligands were made to coordinate to Eu 3+ ion, preparing two binary polymer-rare earth complexes, PS-(MOBA) 3 -Eu(III) and PS-(FBA) 3 -Eu(III) as well as two ternary complexes with phenanthroline (Phen) as the second small-molecule ligand. The luminescence property of theses complexes was mainly examined, and the effect of the two types of substituent groups on the benzene ring of the bonded benzoic acid on the photo physical behavior of these complexes was investigated in depth. The experimental results show that both the two types of substituent groups on the benzene ring of the bonded benzoic acid can effectively strengthen their fluorescence emission intensities, but the mechanisms are different. For MOBA series complexes, through p-π conjugation effect between methoxy group and the π orbit of the bonded ligand MOBA, the triplet state level of the bonded ligand MOBA can be remarkably decline, so the energy level matching degree between the triplet state level of the bonded ligand MOBA and the resonant energy level of Eu(III) ion is greatly enhanced, resulting in a drastically enhancing of the luminescence intensities of the MOBA series complexes. For FBA series complexes, through n–π* transition between the formyl group and π* orbit of the bonded ligand FBA and the accompanying intraligand charge transfer, the triplet state energy of the bonded ligand FBA can also be reduced, and the energy level matching degree can also be improved, leading to an obvious enhancement of luminescence intensities of the complexes.

Preparation of luminescent lanthanide polymers by ring-opening metathesis polymerization

Polymeric lanthanide complexes have been synthesized through ring-opening metathesis polymerization of monomeric lanthanide complexes of pyridine dicarboxylates that contain a norbornene group. The lanthanide monomer complexes, Eu(III) and Tb(III) complexes, have three norbornene groups that allow three-dimensional polymeric networking, and the corresponding polymers of Eu(III), Tb(III), and their equimolar complexes are highly luminescent with intense emission bands in the characteristic visible region.

Preparation and Photoluminescence Properties of Polymer–Rare-Earth Complexes Composed of Bidentate Schiff-Base-Ligand-Functionalized Polysulfone and Eu(III) Ion

A bidentate Schiff-base (SB) ligand was synthesized and bonded on the side chains of polysulfone (PSF) through several polymer reactions by molecular design, and the bidentate Schiff-base-ligand-functionalized PSF, PSF-SB, was obtained. On this basis, new types of polymer–rare-earth complexes, namely, binary complex PSF-(SB)3-Eu(III) and ternary complex PSF-(SB)3-Eu(III)-(Phen)1, were prepared through the coordination reactions between PSF-SB as a macromolecular ligand, 1,10-phenanthroline (Phen) as a second small-molecule ligand, and Eu(III) ion. The functional polymer PSF-SB was fully characterized by FTIR, 1H NMR, and chemical analysis methods, and the complexes were also fully characterized by FTIR and UV absorption spectroscopies. The fluorescence emission characteristics and luminescence mechanism of the complexes were investigated in depth. The experimental results show that the macromolecular ligand PSF-SB itself emits strong fluorescence centered at 415 nm. However, after coordination to Eu(III) ...

Complexations of Ln(III) with SnS4H and Sn2S6: Solvothermal syntheses and characterizations of lanthanide coordination polymers with thiostannate and polyamine mixed ligands

Polymeric lanthanide complexes with thiostannate and polyamine mixed ligands, [Ln(peha)(μ–SnS4H)]n [Ln=La (1a), Nd (1b)] and [{Ln(tepa)(μ–OH)}2(μ–Sn2S6)]nnH2O [Ln=Nd (2a), Sm (2b), Gd (2c), Dy (2d)] (peha=pentaethylenehexamine, tepa=tetraethylenepentamine) were respectively prepared in peha and tepa coordinative solvents by the solvothermal methods. In 1a and 1b, the Ln3+ ions are coordinated by a hexadentate peha ligand forming [Ln(peha)]3+ units. The [SnS4H]3− anion chelates a [Ln(peha)]3+ unit via two S atoms and coordinates to another [Ln(peha)]3+ unit via the third S atom. As a result, the [Ln(peha)]3+ units are connected into coordination polymers [Ln(peha)(μ–SnS4H)]n by an unprecedented tridentate μ–η1,η2–SnS4H bridging ligands. In 2a–2d, the Ln3+ ions are coordinated by a pentadentate tepa ligand, and two [Ln(tepa)]3+ units are joined by two μ–OH bridges to form a binuclear [{Ln(tepa)(μ–OH)}2]4+ unit. Behaving as a bidentate μ–η1, η1–Sn2S6 bridging ligand, the Sn2S6 unit connects [{Ln(tepa)(μ–OH)}2]4+ units into a neutral coordination polymer [{Ln(tepa)(μ–OH)}2(μ–Sn2S6)]n via the trans S atoms. The Ln3+ ions are in distorted monocapped square antiprismatic and bicapped trigonal prismatic environments in [{Ln(peha)(μ–SnS4H)]n and [{Ln(tepa)(μ–OH)}2(μ–Sn2S6)]n, respectively. The denticities of ethylene polyamine play an important role on the formation and complexation of the thiostannate in the presence of lanthanide ions. Compounds 1a–2d show well-defined absorption edges with band gaps between 2.81 and 3.15eV.

Structure and luminescent property of complexes of aryl carboxylic acid-functionalized polystyrene with Eu(III) and Tb(III) ions

Via polymer reactions, naphthoic acid (NA) and benzoic acid (BA) were bonded onto the side chains of polystyrene (PS), respectively, and two aryl carboxylic acid-functionalized polystyrenes, PSNA and PSBA, were obtained. Using PSNA and PSBA as macromolecule ligands and Eu3+ and Tb3+ ions as central ions, various luminescent binary polymer-rare earth complexes were prepared. At the same time, with 1,10-phenanthroline (Phen) and 4,4′-bipyridine (Bipy) as small-molecule co-ligands, various ternary polymer-rare earth complexes were also prepared. On the basis of characterizing PSNA, PSBA and complexes, the relationship between structure and luminescent property for these prepared complexes were mainly investigated. The study results show that the macromolecule ligands PSNA and PSBA, or the bonded NA and BA ligands, can strongly sensitize the fluorescence emissions of Eu3+ ion or Tb3+ ion, but the sensitization effect is strongly dependent on the structure of the ligands and the property of the central ions, namely it is strongly dependent on the matching degree of energy levels. The fluorescence emission of the binary complex PS-(NA)3-Eu(III) is stronger than that PS-(BA)3-Eu(III), indicating ligand NA has stronger sensitization action for Eu3+ ion than ligand BA; the binary complex PS-(BA)3-Tb(III) emit strong characteristic fluorescence of Tb3+ ion, displaying that ligand BA can strongly sensitize Tb3+ ion, whereas the binary complex PS-(NA)3-Tb(III) nearly does not emit the characteristic fluorescence of Tb3+ ion, showing that ligand NA does not sensitize Tb3+ ion. The fluorescence intensity of the ternary complexes is much stronger than that of the binary complexes in the same series.

Structure and photoluminescence property of complexes of aromatic carboxylic acid-functionalized polysulfone with Eu(Ⅲ) and Tb(Ⅲ)

With chloromethylated polysulfone as starting substance, naphthoic acid (NA) and benzoic acid (BA) were bonded onto the side chains of polysulfone (PSF) via polymer reactions, obtaining two kinds of aromatic carboxyl acid-functionalized polysulfone, PSFNA and PSFBA. Subsequently, the luminescent binary and ternary polymer-rare earth complexes of Eu(Ⅲ) and Tb(Ⅲ) were prepared through coordination reactions, respectively, with PSFNA and PSFBA as macromolecule ligands and with 1,10-phenanthroline (Phen) and 4,4′-bipyridine (Bipy) as small-molecule co-ligands. This work focuses on investigating the relationship between structure and photoluminescence property of these complexes. The experimental results indicate that the macromolecule ligands PSFNA and PSFBA can strongly sensitize the fluorescence emissions of Eu3+ ion or Tb3+ ion, and the sensitization effect is strongly dependent on the structure of the ligands and the property of the central ions. The fluorescence emission of the binary complex PSF–(NA)3–Eu(Ⅲ) is stronger than that PSF–(BA)3–Eu(Ⅲ), suggesting the bonded ligand NA has stronger sensitization action for Eu3+ ion than ligand BA; The binary complex PSF–(BA)3–Tb(Ⅲ) emit very strong characteristic fluorescence of Tb3+ ion, displaying that ligand BA can strongly sensitize Tb3+ ion, whereas PSF–(NA)3–Tb(Ⅲ) does not emit the characteristic fluorescence of Tb3+ ion, showing that the bonded ligand NA does not sensitize Tb3+ ion. The fluorescence intensity of the ternary complexes is stronger than that of the binary complexes in the same series. The solid films of these complexes also emit the strong characteristic fluorescence of Eu3+ ion or Tb3+ ion.

Studies on preparation, structure and fluorescence emission of polymer-rare earth complexes composed of aryl carboxylic acid-functionalized polystyrene and Tb(Ⅲ) ion

4-(Chloromethyl) benzoic acid (CMBA) was first bonded onto the side chains of polystyrene (PS) via a polymer reaction, Friedel–Crafts alkylation reaction, and aryl carboxylic acid-functionalized polystyrene (PSBA) was generated. The functionalized polystyrene was used to prepare rare earth metal complexes. By using PSBA as macromolecule ligand, the binary polymer-rare earth complexes, PS-(BA)n-Tb(Ⅲ), were prepared, and at the same time, ternary polymer-rare earth complexes, PS-(BA)n-Tb(Ⅲ)-(Phen)m, i.e. the mixed complexes in which both polymer-based aryl carboxylic acid and 1,10-phenanthroline as ligands were also prepared. The complexes were fully characterized using FTIR and proton NMR spectroscopy. Both ultraviolet absorption and fluorescence emission spectra for the complexes were recorded. The relationship between complex structure and the intensity of fluorescence emission was established. The experimental results show that the fluorescence emission from the central metal ion in the complex is strongly sensitized by the aryl carboxylic acid ligands chemically attached to the side chains of PSBA, and an apparent “Antenna Effect” is produced for these complexes. In the dilute solution of PSBA, the formed complex belongs to intramolecular complex. For the binary intramolecular complex, the apparent saturated coordination number of Tb3+ ion is 10, and here the binary complex has the structure of PS-(BA)5-Tb(Ⅲ) and it has the strongest fluorescence emission among all of the binary complexes. When small-molecule Phen is added into the binary complex solution, the ternary complex PS-(BA)n-Tb(Ⅲ)-(Phen)m will be formed. As compared with the conventional ternary complexes PS-(BA)1-Tb(Ⅲ)-Phen2 and PS-(BA)1-Tb(Ⅲ)-(Phen)3 (the molar ratio of the central ion and the two ligands is conventional), the ternary complex with the structure of PS-(BA)5-Tb(Ⅲ)-(Phen)1 has the strongest fluorescence emission because of the complete coordination of the ligands to Tb3+ ion and the removal of the substituted water molecules around Tb3+ ion.

Preparation of aromatic carboxylic acid-functionalized polysulfone and preliminary exploration of florescence emission character of formed polymer-rare earth complexes

Polysulfone (PSF) was modified via a polymer reaction, Friedel–Crafts alkylation of PSF with 4-(chloromethyl) benzoic acid (CMBA) as reaction reagent, and benzoic acid (BA) ligand was bonded onto the side chains of PSF, resulting in the aromatic carboxylic acid-functionalized PSF, BAPSF. The chemical structure of BAPSF was characterized by FTIR, 1H NMR and UV/vis absorption spectrum. BAPSF was allowed to coordinate to Eu(III) and Tb(III) ions, respectively, and two luminescent polymer-rare earth complexes, BAPSF-Eu(III) and BAPSF-Tb(III) were prepared. The fluorescence emission character of the two complexes was preliminarily explored. The functionalization modification process of PSF and the reaction mechanism were emphatically investigated. The experimental results show that the Friedel–Crafts alkylation reaction between PSF and CMBA can be carried out smoothly. The two polymer-rare earth complexes, BAPSF-Eu(III) and BAPSF-Tb(III), exhibit the characteristic fluorescence emissions of Eu3+ and Tb3+ ions, respectively. More importantly, BAPSF can powerfully sensitize the fluorescence emissions of Eu3+ and Tb3+ ions, and the effective energy transfer indeed take places from the macromolecular ligand BAPSF to the coordinated Re3+ and Tb3+ ions.

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.

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.