Synthesis,Structures, and Luminescent Properties of Chloride and Nitrate LnIII Complexes Coordinated by tris(Pyrazolyl)methane

We report the synthesis of Ln³⁺ nitrate [Ln(Tpm)(NO₃)₃] ⋅ MeCN (Ln=Yb ( 1Yb ), Eu ( 1Eu )) and chloride [Yb(Tpm)Cl₃] ⋅ 2MeCN ( 2Yb ), [Eu(Tpm)Cl₂(μ-Cl)]₂ ( 2Eu ) complexes coordinated by neutral tripodal tris(3,5-dimethylpyrazolyl)methane (Tpm). The crystal structures of 1Ln and 2Ln were established by single crystal X-ray diffraction, while for 1Yb high resolution experiment was performed. Nitrate complexes 1Ln are isomorphous and both adopt mononuclear structure. Chloride 2Yb is monomeric, while Eu³⁺ analogue 2Eu adopts a binuclear structure due to two μ²-bridging chloride ligands. The typical lanthanide luminescence was observed for europium complexes ( 1Eu and 2Eu ) as well as for terbium and dysprosium analogues ([Ln(Tpm)(NO₃)₃] ⋅ MeCN, Ln=Tb ( 1Tb ), Dy ( 1Dy ); [Ln(Tpm)Cl₃] ⋅ 2MeCN, Ln=Tb ( 2Tb ), Dy ( 2Dy )).     

2,2′‐Bipyrimidine as Efficient Sensitizer of the Solid‐State Luminescence of Lanthanide and Uranyl Ions from Visible to Near‐Infrared

Treatment of Ln(NO₃)₃?nH₂O with 1 or 2 equiv 2,2′‐bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [Ln(NO₃)₃(bpm)₂] (Ln=Eu, Gd, Dy, Tm) or [Ln(NO₃)₃(bpm)₂]?THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [Ln(NO₃)₃(bpm)₂]?THF (Ln=Nd, Sm) from THF, or [Ln(NO₃)₃(bpm)(MeOH)₂]?MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO₂(NO₃)₂?6H₂O with 1 equiv BPM in THF afforded the monoadduct [UO₂(NO₃)₂(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid‐state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the Yb^III ion emitting in the near‐IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8 %, respectively. All these complexes in the solid state were stable in air.     

3-((4，6-二甲基-2-嘧啶基)硫代)-丙酸和菲咯啉三元稀土配合物的晶体结构和发光性能

制备了以3-((4,6-二甲基-2-嘧啶基)硫代)-丙酸(HL)和菲咯啉(Phen)为配体的2个三元稀土配合物[Eu(L)₃(Phen)]₂·2H₂O(1)和[Tb(L)₃(Phen)]₂·2H₂O(2),并对其结构进行了表征。单晶X射线衍射分析表明它们是同构的。2个稀土离子(Ln)由4个羧酸配体桥接,形成二聚体排列。其余2个羧酸配体和Phen以双齿螯合方式与Ln配位。Ln的配位数为9,具有扭曲的单端方形反棱柱配位多面体构型。固态光致发光测试表明,这2种配合物都显示了金属中心的特征发射带。     

The first in situ tetrazole synthesis of lanthanide metal coordination frameworks

Hydrothermal reaction of 4-cyanobenzoic acid with NaN₃ in the presence of Ln(NO₃)₃?·?6H₂O produced two lanthanide complexes, [LnL(HL)(H₂O)₅] [Ln?=?Eu (1) and Tb (2)] (H₂L?=?4-(1H-tetrazol-5-yl)benzoic acid). Both compounds were structurally characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Complexes 1 and 2 are isostructural and display 3-D supramolecular frameworks. Solid-state properties such as thermal behaviors and photoluminescence for these crystalline materials were also investigated.     

Synthesis and structure of lanthanide complexes with large-bite diphosphine dioxide ligands

Three large-bite diphosphine dioxide ligands were reacted with lanthanide salts to yield either molecular or polymeric complexes. The two flexible ligands gave bischelate complexes of general formulae [Ln(dppfO₂)₂Cl_x(NO₃)_2−x][FeCl₄] and [Ln(dppdO₂)₂(NO₃)₂]NO₃, where dppfO₂ and dppdO₂ are bis(diphenylphosphoryl)ferrocene and bis(diphenylphosphoryl)diphenyl ether, respectively. Reactions of the rigid bis(diphenylphosphoryl)benzene (dppbO₂) with lanthanide salts yielded linear coordination polymers of a 1:1.5 metal-to-ligand stoichiometry. The compounds were studied by single crystal X-ray diffraction, IR spectroscopy, mass spectrometry, and TG/DSC techniques.     

Lanthanide(III) (Eu,Gd, Tb,Dy) Complexes Derived from 4‐(Pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole: Crystal Structure,Magnetic Properties,and Photoluminescence

The reaction of lanthanide(III) nitrates with 4‐(pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole (L) was studied. The compounds [Ln(NO₃)₃(H₂O)₃] ? 2 L, in which Ln=Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), or Dy ( 4 ), obtained in a mixture of MeCN/EtOH have the same structure, as shown by XRD. In the crystals of these compounds, the mononuclear complex units [Ln(NO₃)₃(H₂O)₃] are linked to L molecules through intermolecular hydrogen‐bonding interactions to form a 2D polymeric supramolecular architecture. An investigation into the optical characteristics of the Eu³⁺‐, Tb³⁺‐, and Dy³⁺‐containing compounds ( 1 , 3 , and 4 ) showed that these complexes displayed metal‐centered luminescence. According to magnetic measurements, compound 4 exhibits single‐ion magnet behavior, with ΔE_eff/k_B=86 K in a field of 1500 Oe.     

Lanthanide nitrate complexes of diphenylmethylphosphine oxide: synthesis and spectroscopic studies. Crystal structures of [La(Ph2MePO)3(NO3)3], [La(Ph2MePO)4(NO3)3]·xMe2CO and [Yb(Ph2MePO)4(NO3)2]PF6

The reaction of Ln(NO₃)₃·6H₂O (Ln=lanthanide except Pm) with Ph₂MePO in a 1:3 or 1:4 ratio in acetone or ethanol produces [Ln(Ph₂MePO)₃(NO₃)₃] which have been characterised by analysis, IR, ¹H and ³¹P{¹H} NMR spectroscopy and conductance measurements. The [Ln′(Ph₂MePO)₃(NO₃)₃] (Ln′=Pr–Tb) exist only as tris complexes in solution and are unaffected by the presence of excess Ph₂MePO. In contrast the [Ln″(Ph₂MePO)₃(NO₃)₃] (Ln″=Ho–Lu) partially decompose in CH₂Cl₂ solution into [Ln″(Ph₂MePO)₄(NO₃)₂]⁺, and [Ln″(Ph₂MePO)₄(NO₃)₂]PF₆ are readily isolated from Ln″(NO₃)₃, Ph₂MePO and NH₄PF₆ in acetone. For lanthanum only, a neutral 1:4 complex [La(Ph₂MePO)₄(NO₃)₃] was isolated. X-ray crystal structures show that [La(Ph₂MePO)₃(NO₃)₃] contains nine-coordinate La, whilst [La(Ph₂MePO)₄(NO₃)₃]·xMe₂CO contains a ten-coordinate metal centre. The structure of [Yb(Ph₂MePO)₄(NO₃)₂]PF₆ reveals an eight-coordinate cation and all complexes contain bidentate nitrato-groups.     

Synthesis, characterization, thermal stability, reactivity, and antimicrobial properties of some novel lanthanide(III) complexes of 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene

Two series of new lanthanide(III) complexes of the type [Ln(HSAT)₂(H₂O)₃Cl₃] and [Ln(HSAT)₂(NO₃)₃], where Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Tm, Yb, or Lu, and HSAT = 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene, are synthesized by the reaction of LnCl₃ or Ln(NO₃)₃ with the title ligand in ethanol. The complexes are characterized by elemental analysis, magnetic moment values, molar conductivity, IR, UV-Vis, and ¹H NMR spectral data. Two selected complexes are subject to thermogravimetric analysis, and their kinetic parameters are estimated using Coats-Redfern equation. The complex [La(HSAT)₂(NO₃)₃] underwent facile transesterification when refluxed in methanol. The ligand and some selected complexes are screened for their antimicrobial properties. Antimicrobial activities of the ligand increase on coordination with the metal ion. The text was submitted by the authors in English.     

Transition metal complexes with pyrazole-based ligands. Part 28. Synthesis,structural, DFT and thermal studies of cadmium(II) halides and zinc(II) chloride complexes with 3,5-dimethylpyrazole-1-carboxamidine

The complex formation of 3,5-dimethylpyrazole-1-carboxamidinium nitrate, HL·HNO₃ with ammine complexes of cadmium(II) halides (Cl, Br, I) and zinc(II) chloride has been investigated under self-controlled reaction conditions. The complexes have been characterized by X-ray diffraction, FT-IR spectroscopy, thermal analysis and quantum chemical calculations. In the case of cadmium bromide and iodide salts, isostructural complexes with composition of [CdX₂(HL)₂] were formed. With CdCl₂ a binuclear octahedral [Cd₂(HL)₄(μ-Cl)₂](NO₃)₂ complex is obtained. Zinc(II) chloride with HL·HNO₃ gives [Zn(HL)₂Cl]NO₃, the zinc center exhibiting severely distorted five-coordinate stereochemistry, intermediate between an ideal trigonal bipyramid and a square pyramid. The course of complex formation as well as the thermal properties of the compounds has been explained using the HSAB principle. The assignment of the FT-IR spectra was supported by DFT computations.     

Identification of the Structural Boundary between [Ln(18‐crown‐6)(NO3)3] and [Ln(NO3)3(H2O)3] · 18‐crown‐6 Motifs in the Lanthanide Series

Recrystallization of Ln(NO₃)₃ (Ln = Sm, Eu, Yb) in the presence of 18‐crown‐6 under aqueous conditions yielded [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6. X‐ray crystallography revealed isomorphous structures for each of the lanthanide complexes where [Ln(NO₃)₃(H₂O)₃] is involved in hydrogen bonding interactions with 18‐crown‐6. The transition point where the structural motif changes from [Ln(18‐crown‐6)(NO₃)₃] (with the metal residing in the crown cavity) to [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6 has been identified as at the Nd/Sm interface. A similar investigation involving [Ln(tos)₃(H₂O)₆] (tos = p‐toluenesulfonate) and 18‐crown‐6 were resistant to crown incorporation. X‐ray studies show extensive intra‐ and intermolecular hydrogen bonding is present.     

Synthesis,structure, and luminescent properties of lanthanide coordination compounds with 3-methyl-4-formyl-1-phenylpyrazol-5-one

An exchange reaction of the sodium salt of 3-methyl-1-phenyl-4-formylpyrazol-5-one (HL) with chlorides or nitrates of lanthanides (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, and Yb) was used to synthesize coordination compounds of composition LnL₃·nSolv (Solv = H₂O or EtOH). According to powder X-ray diffraction data, these compounds constitute two series: one comprises lanthanum and neodymium complexes, and the other, samarium, europium, gadolinium, terbium, dysprosium, and ytterbium complexes. For the complexes of the first series, the structure was solved in a single-crystal diffraction experiment carried out on [La₂(μ-L)₃(L)₃(H₂O)₃]·2MeOH. The lanthanum atoms in the complex are at a distance of 4.222(2) — from each other, and they are structurally nonequivalent and linked by three 5-hydroxy-4-formylpyrazole anions. Solid-phase samples of the coordination compounds under study feature weak luminescence in the spectral regions intrinsic to lanthanide cations.     

3-((4，6-二甲基-2-嘧啶基)硫代)-丙酸和菲咯啉三元稀土配合物的晶体结构和发光性能

制备了以3-((4,6-二甲基-2-嘧啶基)硫代)-丙酸(HL)和菲咯啉(Phen)为配体的2个三元稀土配合物[Eu(L)₃(Phen)]₂·2H₂O(1)和[Tb(L)₃(Phen)]₂·2H₂O(2),并对其结构进行了表征。单晶X射线衍射分析表明它们是同构的。2个稀土离子(Ln)由4个羧酸配体桥接,形成二聚体排列。其余2个羧酸配体和Phen以双齿螯合方式与Ln配位。Ln的配位数为9,具有扭曲的单端方形反棱柱配位多面体构型。固态光致发光测试表明,这2种配合物都显示了金属中心的特征发射带。     

Synthesis and photoluminescence of complexes Tm(L)(iso-Bu2PS2)2(NO3) (L = Phen, 2,2′-Bipy). Crystal structures of compounds [Ln(2,2′-Bipy)(iso-Bu2PS2)2(NO3)] · C6H6 (Ln = Tm, Tb)

Heteroligand complexes Tm(L)(iso-Bu₂PS₂)₂(NO₃) (L = 2,2′-Bipy (II), Phen (III)) are synthesized. According to the X-ray phase analysis data, complex III is isostructural to mononuclear compound [Dy(Phen)(iso-Bu₂PS₂)₂(NO₃)] including, according to the X-ray diffraction data, a coordination polyhedron DyN₂O₂S₄ (distorted dodecahedron). Single crystals of compounds [Ln(2,2′-Bipy)(iso-Bu₂PS₂)₂(NO₃)] · C₆H₆ (Ln = Tm (IV), Tb (V)) are obtained. An X-ray diffraction analysis shows that the crystal structures of these isostructural compounds are formed by molecules of mononuclear complexes [Ln(2,2′-Bipy)(iso-Bu₂PS₂)₂(NO₃) and uncoordinated C₆H₆ molecules. In complexes IV and V, the ligands [Ln(2,2′-Bipy)(iso-Bu₂PS ₂ ^? , and NO ₃ ^? are bidentate-cyclic. The coordination polyhedron LnN₂O₂S₄ is a distorted dodecahedron. Complexes II and III possess photoluminescence in the visible spectral range (λ_max = 478 and 477 nm, respectively).     

Synthesis,crystal structures and NIR luminescence of sandwich-like tetradentate salophen phenoxo-bridged heterotrinuclear metal complexes

Six phenoxo-bridged tetradentate salophen heterotrinuclear Zn₂Ln complexes, [Ln(ZnL)₂(NO₃)₃(CH₃OH)₂]·CH₃OH·CH₂Cl₂ [Ln?=?Pr (1), Nd (2)] and [Ln(ZnL)₂(NO₃)₃(CH₃OH)]·CH₃OH·CH₂Cl₂ [Ln?=?Eu (3), Ho (4), Er (5), and Yb (6)], have been isolated from reactions of N,N′-bis(salicylidene)-1,2-(phenylene-diamine) with Ln(NO₃)₃6H₂O and Zn(OAc)₂2H₂O. X-ray diffraction analysis reveals that 1–6 are isomorphic with phenoxo-bridged, sandwich-like {Zn₂Ln} core. Near infrared (NIR) luminescence spectra show that 6 exhibits typical emission of Yb³⁺ upon excitation at the ligand-centered absorption band at 357?nm.     

Synthesis,molecular and crystal structure,magnetic properties,luminescence, and solid-phase thermolysis of binuclear Ln(III) pivalates with 2,2′-dipyridyl and 1,10-phenanthroline molecules

Methods of synthesis of binuclear pivalate complexes L₂Ln₂(μ-O,η²-OOCCMe₃)₂(μ₂-O,O′-OOCCMe₃)₂(η²-OOCCMe₃)₂, where Ln = Sm, Eu, Gd, or Er and L = 2,2′-dipyridyl (Bipy) or 1,10-phenanthroline (Phen), from the corresponding binuclear complexes Ln₂(μ₂-OOCCMe₃)₄(OOCCMe₃)₂(HOOCCMe₃)₆ · HOOCCMe₃(I–IV), as well as of coordination polymers {Ln(OOCCMe₃)₃} _n , were suggested. The compounds were characterized by X-ray crystallography and X-ray powder diffraction and their magnetic properties, solid-phase thermolysis, and the phase composition of solid decomposition products were studied. The structures of the metal carboxylate core and surrounding ligands were shown to have an effect on the thermal stability of the complexes. The luminescence properties of the Eu(III) complexes were analyzed.     

Liquid-Crystalline and Orientation Properties of Lanthanide Complexes with β-Enaminoketone

A series of liquid-crystalline lanthanide complexes with 1-(4-dodecyloxyphenyl)-3-octadecylamino-2-propene-1-one (HL), which is substituted β-enaminoketone, with the composition Ln(HL)₃(NO₃)₃ (Ln = La, Nd, Gd, Tb, Dy, Ho, and Er) is synthesized. For the most part of the synthesized complexes, the magnetic susceptibility anisotropy (Δχ_min) is shown to be one to two orders higher than Δχ of the “classical” organic liquid crystals.     

Synthesis, spectroscopic characterization, and antimicrobial activity of cobalt(II) complexes of acetone-N(4)-phenylsemicarbazone: crystal structure of [Co(HL)2(MeOH)2](NO3)2

Four Co(II) complexes, [Co(HL)₂](OAc)₂, [Co(HL)₂Cl₂], [Co(HL)₂(MeOH)₂](NO₃)₂, and [Co₂(HL)₄(SO₄)₂] (HL = acetone-N(4)-phenylsemicarbazone) were synthesized and characterized by physicochemical and spectroscopic methods. The magnetic susceptibility measurements indicate that the complexes are paramagnetic with three unpaired electrons. In all the complexes, the semicarbazone is coordinated as a neutral bidentate ligand. The structure of [Co(HL)₂(MeOH)₂](NO₃)₂ was confirmed by single crystal X-ray crystallography. The ligand is neutral and bidentate, being coordinated to the cobalt atom through the carbonyl oxygen and the azomethine nitrogen. Intermolecular hydrogen bonding and C–H···π interactions combine to stabilize the crystal structure. The ligand and its two complexes [Co(HL)₂Cl₂] and [Co(HL)₂(MeOH)₂](NO₃)₂ were screened for their antibacterial and antifungal activities using disk diffusion methods.     

Tetrathiafulvalene-based lanthanide coordination complexes: Synthesis,crystal structure,optical and electrochemical characterization

The explorative lanthanide coordination chemistry of 4′,5′-bis-(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2′,3′-c]phenazine (TTF-dppz) is described. Thereby, four new Ln(III) complexes, [Ln(NO₃)₃(TTF-dppz)₂] with Ln(III) = Nd (1), Eu (2), Gd (3), Tb (4), have been prepared and characterized. An X-ray crystallographic study of [Gd(NO₃)₃(TTF-dppz)₂] (3) shows that the Gd(III) ion is coordinated to six oxygen atoms from three bidentate nitrate ligands and four nitrogen atoms from two bidentate TTF-dppz molecules forming a distorted bicapped square antiprism coordination geometry. The UV-vis spectra of the four Ln(III) complexes show very strong absorption bands in the UV region consistent with ligand centred electronic π-π* transitions and an intense broad absorption band in the visible region corresponding to a spin-allowed electronic π-π* ¹ILCT transition from the TTF-dppz ligand. Upon coordination, the ¹ILCT band of the free TTF-dppz ligand is bathochromically shifted. The electrochemical studies reveal that all complexes undergo two reversible oxidation and one (quasi)reversible reduction processes, ascribed to the successive oxidations of the TTF moiety and the reduction of the dppz unit, respectively. Moreover, the magnetic properties of complexes 3 and 4 are discussed.     

Preparation of photoluminescent compounds of Eu(III), Sm(III), and Dy(III) containing anions of tetrafluoroterephthalic acid

The Ln₂(H₂O)₄(L)₃·2H₂O and Ln₂(phen)₂(L)₃·2H₂O complexes [Ln = Eu(III), Sm(III), or Dy(III); H₂L = C₆F₄(COOH)₂, phen = 1,10-phenanthroline] have been prepared. Structures of the prepared compounds have been confirmed by X-ray diffraction and IR spectroscopy studies. The complexes of Eu(III) have exhibited red photoluminescence stronger than that of the complexes of Sm(III) and Dy(III).     

Synthesis and crystal structure of yttrium(III) and lanthanide(III) complexes with a new terpyridine-like ligand 2,4-bis(3,5-dimethylpyrazol-1-yl)- 6-diethylamino-1,3,5-triazine

A new planar aromatic tridentate terpyridine-like ligand, 2,4-bis(3,5-dimethylpyrazol-1-yl)-6-diethylamino-1,3,5-triazine (L), has been synthesized and the structures of its complexes [YL(NO₃)₃] (1) and [LnL(NO₃)₃(H₂O)]L [Ln?=?La (2), Ce (3), Pr (4), Nd (5), Eu (6)] have been determined by X-ray crystal structural analysis. The structures of the five lanthanoid complexes are isomorphous and isostructural but different from the crystal structure of the yttrium complex [YL(NO₃)₃]. The latter shows a nine-coordinate metal center whereas the crystal structure of the lanthanoid complexes [LnL(NO₃)₃(H₂O)]L show a 10-coordinate metal center. The?π–π?stacking and hydrogen bonding between the coordinated and uncoordinated L molecules sensitized the Ln luminescence. The thermal behavior of the ligand and its complexes is discussed.