Crystal structure and luminescence property of novel three-dimensional network of {Eu2(p-BDC)3(Phen)2(H2O)2}n

The single crystal of a supramolecule, {Eu₂(p-BDC)₃(Phen)₂(H₂O)₂}_n (p-BDC=1,4-benzenedicarboxylate), with characteristic luminescence of Eu³⁺ was obtained by means of soft chemistry. The crystal structure determination reveals that each Eu³⁺ ion is coordinated by five oxygen atoms of p-BDC anions, one oxygen atom from water molecule, and two nitrogen atoms of Phen, respectively, resulting in an eight-coordinated Eu³⁺ center and a distorted square antiprism coordination polyhedron. Four bridges, two carboxylates of μ₄-p-BDC and two of μ₃-p-BDC, connect two Eu atoms into a binuclear unit. Moreover, the μ₃-p-BDC integrates the binuclear building blocks at the direction of b axis and the μ₄-p-BDC polymerizes the structure roughly along the direction of the sum vector of axis b and c, respectively, forming two-dimensional layers. Hydrogen bonds between layers make the structure a three-dimensional network. The luminescence spectra measured under 77 K demonstrate the antenna effect of Phen and the ⁵D₁→⁵D₀ energy transfer path within Eu³⁺ ion. Both luminescence spectra and crystal structure lead to the conclusion that the local symmetry around the Eu³⁺ ion is C₁ and that more than one Eu³⁺ ion sites having slight environmental difference are present.     

Syntheses,structures and luminescent properties of four copper(I) cyanide coordination polymers based on 2-(n-pyridyl)benzimidazole ligands (n = 2, 3, 4)

Four copper(I) cyanide coordination polymers containing 2-(n-pyridyl)benzimidazole ligands, namely [Cu₂(CN)(2-PyBIm)]_n (1), [Cu₂(CN)₂(3-PyHBIm)]_n (2), {[Cu₃(CN)₃(4-PyHBIm)₄] · 2H₂O}_n (3) and [Cu₅(CN)₃(4-PyBIm)₂]_n (4), have been synthesized and characterized by X-ray crystallography. Complex 1 is a one-dimension coordination polymer in which 2-(2-pyridyl)benzimidazole is deprotonated and adopts a bridging tridentate coordination mode. Complex 2 has ladder-like structure in which 2-(3-pyridyl)benzimidazole does not deprotonate and acts as a bidentate bridge. Complex 3 displays a saddle-shaped helical chain constructed through μ₂-cyanide group and the outstretched neutral 2-(4-pyridyl)benzimidazole monodentate ligand. Complex 4 shows two-dimension layer polymeric structure in which deprotonated 2-(4-pyridyl)benzimidazole acts as a tridentate bridging ligand. The cyanide groups in four complexes all act as bidentate bridging ligands. These complexes are thermal stable and display luminescence in the solid states.     

Preparation, spectroscopic properties of 1,4-di (N,N-diisopropylacetamido)-2,3(1H,4H)-quinoxalinedione (L) lanthanide complexes and the supramolecular structure of [Nd2L2(NO3)6(H2O)2]·H2O

The reaction of lanthanide nitrate with 1,4-di (N,N-diisopropylacetamido)-2,3(1H,4H)-quinoxalinedione (L) yields six novel Ln(III) complexes ([Ln₂L₂(NO₃)₆(H₂O)₂]·H₂O) which are characterized by elemental analysis, thermogravimetric analysis (TGA), conductivity measurements, IR, electronic and ¹H NMR spectroscopies. A new quinoxalinedione-based ligand is used as antenna ligand to sensitize the emission of lanthanide cations. The lowest triplet state energy level of the ligand in the nitrate complex matches better to the resonance level of Eu(III) and Sm(III) than Tb(III) and Dy(III) ion. The f-f fluorescence is induced in the Eu³⁺ and Sm³⁺ complexes by exciting into the π-π* absorptions of the ligand in the UV. Furthermore, the crystal structures of a novel binuclear complex [Nd₂L₂(NO₃)₆(H₂O)₂]·H₂O has been determined by single-crystal X-ray diffraction. The binuclear [Nd₂L₂(NO₃)₆(H₂O)₂]·H₂O complex units are linked by the intermolecular hydrogen bonds and π-π interactions to form a two-dimensional (2-D) layer supramolecule.     

Synthesis and structure of two lanthanide complexes with isonicotinic acid N-oxide (HL): [Ln(L)2(H2O)4]n·(NO3)n·n(H2O) (Ln = Sm or Tb)

Two new lanthanide complexes of isonicotinic acid N-oxide (HL), namely [Ln(L)₂(H₂O)₄]_n·(NO₃)_n·n(H₂O) for Ln = Sm or Tb, have been synthesized and characterized by spectroscopic and crystallographic methods. IR spectra suggest that isonicotinic acid N-oxide acts as a O,O′-bidentate ligand, the N-oxide group as well as the nitrate group are not involved in coordination. Single crystal analyses have shown that both complexes are isomorphous, where the Ln(III) centers are eight coordinated by four O atoms of four water ligands and other four O atoms of two isonicotinic acid N-oxide ligands. The carboxylate groups are only involved in the bidentate syn–syn bridging mode into infinite chains. Hydrogen bonds between aqua ligands, lattice molecules, nitrate and N-oxide groups are formed giving a three-dimensional network.     

Syntheses, crystal structures and optical spectroscopy of Ln2(SO4)3·8H2O (Ln=Ho, Tm) and Pr2(SO4)3·4H2O

The lanthanide sulphate octahydrates Ln₂(SO₄)₃·8H₂O (Ln=Ho, Tm) and the respective tetrahydrate Pr₂(SO₄)₃·4H₂O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln₂(SO₄)₃·8H₂O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, a_Ho=13.4421(4) Å, b_Ho=6.6745(2) Å, c_Ho=18.1642(5) Å, β_Ho=102.006(1) Å³ and a_Tm=13.4118(14) Å, b_Tm=6.6402(6) Å, c_Tm=18.1040(16) Å, β_Tm=101.980(8) Å³), Pr₂(SO₄)₃·4H₂O adopts space group P2₁/n (a=13.051(3) Å, b=7.2047(14) Å, c=13.316(3) Å, β=92.55(3) Å³). The vibrational and optical spectra of Ho₂(SO₄)₃·8H₂O and Pr₂(SO₄)₃·4H₂O are also reported.     

Spectral properties of Eu(III) compound with antibacterial agent ciprofloxacin (cfqH). Crystal structure of [Eu(cfqH)(cfq)(H2O)4]Cl2 · 4.55H2O

A novel europium complex of fluoroquinolone ciprofloxacin (cfqH) with formula [Eu(cfqH)(cfq)(H₂O)₄]Cl₂ · 4.55H₂O (1) was synthesized and its crystal structure determined by X-ray crystallography. The coordination number of europium is eight and in this structure two bidentate, O,O-bonded quinolone molecules and four aqua ligands are coordinated to the metal. One molecule of quinolone is anionic whereas the other is zwitterionic. Additionally, two chloride ions are also present in the structure to compensate the charge of the europium(III) whilst disordered solvent water molecules too are present. The spectral properties (IR, Raman, luminescence) of compound 1 were studied. Analysis of the Stark structure of the luminescence spectra was carried out and the scheme of the electronically excited states and photophysical processes of compound 1 was arranged. The spectral properties show that europium–ciprofloxacin complexes could be suitable for various applications based on their solution-state stability as measured by ¹H and ¹⁹F NMR.     

Reassignment of the crystal space group of crystalline Pr[M(CN)6] · 5H2O (M = Cr,Fe, Co)

Refinement of the X-ray crystal structures of Pr[M(CN)₆] · 5H₂O (M = Cr, Fe, Co) enables their space group to be reassigned to P6₃/mmc. Spectral characteristics are reported for M = Cr and the distinction between the pentahydrate and tetrahydrate series is clearly made from assignments of the infrared spectra.     

Syntheses and characterization of Co(pydc)(H2O)2 and Ni(pydc)(H2O) (pydc = 3,5-pyridinedicarboxylate)

The hydrothermal reaction of 3,5-pyridinedicarboxylic acid (pydcH₂) and Co(NO₃)₂ or Ni(NO₃)₂ in the presence of 4,4′-bipyridine results in two novel compounds Co(pydc)(H₂O)₂ (1) and Ni(pydc)(H₂O) (2). Crystal data: 1, monoclinic, C2/c, a=9.900(2), b=11.984(2), c=7.3748(15) Å, β=105.37(3)°, V=843.7(3) Å³, Z=4; 2, monoclinic, P2₁/c, a=7.7496(6), b=15.0496(11), c=6.4224(5) Å, β=108.437(1)°, V=710.59(9) Å³, Z=4. The structure of 1 is composed of honeycomb layers built up from {CoO₄N} trigonal bipyramids and 3,5-pyridinedicarboxylate bridges. The structure of 2 adopts a three-dimensional framework structure in which the Ni atoms are coordinated by the pydc bridges both within the honeycomb layer and between the layers. The magnetic properties of 1 and 2 have been investigated.     

[H2en]2{La2M(SO4)6(H2O)2} (M=Co, Ni): First organically templated 3d-4f mixed metal sulfates

The first organically templated 3d-4f mixed metal sulfates, [H₂en]₂{La₂M(SO₄)₆(H₂O)₂} (M=Co 1, Ni 2) have been synthesized and structurally determined from non-merohedrally twinned crystals. The two compounds are isostructural and their structures feature a three-dimensional anionic network formed by the lanthanum(III) and nickel(II) ions bridged by sulfate anions. The La(III) ions in both compounds are 10-coordinated by four sulfate anions in bidentate chelating fashion, and two sulfate anions in a unidentate fashion. The transition metal(II) ion is octahedrally coordinated by six oxygens from four sulfate anions and two aqua ligands. The doubly protonated enthylenediamine cations are located at the tunnels formed by 8-membered rings (four La and four sulfate anions).     

Nano/micro-scaled La(1,3,5-BTC)(H2O)6 coordination polymer: Facile morphology-controlled fabrication and color-tunable photoluminescence properties by co-doping Eu,Tb

Nano/micro-sized coordination polymer La(1,3,5-BTC)(H₂O)₆ with controllable morphologies have been successfully prepared on a large scale via a simple solution phase method at room temperature. By rationally adjusting the synthetic parameters such as concentration, molar ratio of reactants, surfactant, and solvent, the La(1,3,5-BTC)(H₂O)₆ with 3D flowerlike, wheatearlike, spherical, sheaflike, taillike, bundlelike hierarchical architectures, and 1D nanorods can be selectively prepared. More interestingly, the photoluminescence color of codoped Eu³⁺ and Tb³⁺ lanthanum 1,3,5-benzenetricarboxylate phosphors can be easily tuned from red, orange, yellow, green-yellow to green by changing co-doping concentration of activator ions, making the material has potential applications in building minioptoelectronic devices, biomedicine, and color display fields.     

Syntheses, characterization and sensitized lanthanide luminescence of heteronuclear Pt-Ln (Ln = Eu, Nd, Yb) complexes with 2,2′-bipyridyl ethynyl ligands

Reaction of [Pt()Cl]⁺ ( = 4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine) with 5-ethynyl-2,2′-bipyridine (HCCbpy) or 5,5′-bis(trimethylsilylethynyl)-2,2′-bipyridine (Me₃SiCCbpyCCSiMe₃) in the presence of cuprous iodide gives [Pt(^tBu₃tpy)(CCbpy)]⁺ (1) or [{Pt()}₂(CCbpyCC)]²⁺ (2) through Pt-acetylide σ-coordination, respectively. Incorporating 1 or 2 with Ln(hfac)₃(H₂O)₂ through 2,2′-bipyridyl chelating the Ln^III (Ln = Nd, Eu, and Yb) centers induces formation of a series of [Pt()(CCbpy){Ln(hfac)₃}]⁺ (PtLn) or [{Pt()}₂(CCbpyCC){Ln(hfac)₃}]²⁺ (Pt₂Ln) complexes, respectively. The structures of binuclear platinum(II) complex 2(PF₆)₂ and heterobinuclear PtNd complex 3(CF₃COO) were determined by single crystal X-ray diffraction. Both 1 and 2 exhibit typical low-energy absorption bands in near UV-Vis region, ascribed to dπ(Pt) → π^∗() MLCT and π(CCbpy/CCbpyCC) → π^∗() LLCT transitions. Upon formation of the PtLn or PtLn₂ complexes, the low-energy absorption bands are obviously blue-shifted (15-20 nm) compared with those in the Pt^II precursor 1 or 2. With excitation at 350 nm < λ < 550 nm which is the absorption region of MLCT and LLCT transitions, sensitized luminescence that is characteristic of the corresponding lanthanide(III) ions occurs in both PtLn and Pt₂Ln complexes. In contrast, Pt-based luminescence from the MLCT and LLCT states are mostly quenched in these Pt-Ln heteronuclear complexes, revealing that quite effective Pt → Ln energy transfer is operating from the Pt()(acetylide) chromophore to the lanthanide(III) centers.     

A series of three-dimensional coordination polymers with general formula [{Ln(H2O)n}{Re6Te8(CN)6}] · xH2O (Ln = Eu,Gd, Tb,Dy, Ho,Er, Tm,Yb; n = 3, 4, x = 0, 2.5)

A series of new compounds containing rare earth cations (Eu to Yb) and paramagnetic cluster anion [Re₆Te₈(CN)₆]³⁻ was prepared and investigated. The X-ray structural analyses have revealed that the compounds [{Ln(H₂O)₄}{Re₆Te₈(CN)₆}] · 2.5H₂O; Ln = Eu (1), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), [{Gd(H₂O)₃}{Re₆Te₈(CN)₆}] · 2.5H₂O (2) and [{Yb(H₂O)₄}{Re₆Te₈(CN)₆}] (8) are three-dimensional polymers based on Re–CN–Ln interactions. Measurements of magnetic susceptibility for 2 and 5 showed that effective magnetic moment (at 300 K) was 8.13 μ_B for compound 2 and 10.79 μ_B for compound 5 with weak antiferromagnetic ordering appeared at low temperatures.     

Calorimetric study and thermal analysis of [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O and [ErY(Gly)6(H2O)4](ClO4)6·5H2O (Gly: glycin)

Two solid-state coordination compounds of rare earth metals with glycin, [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O and [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 342.90 K, while [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol⁻¹ and 53.9 J K⁻¹ mol⁻¹ for [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, 1.82 kJ mol⁻¹ and 5.5 J K⁻¹ mol⁻¹ for [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed.     

Two tantalum fluorides templated with tren: [H4tren](TaF7)2·H2O and [H4tren](TaF7)2

Using tris(2-aminoethyl)amine [(C₂H₄NH₂)₃N] (tren) as a template, two new tantalum fluorides are obtained by slow evaporation of solutions: [H₄tren](TaF₇)₂·H₂O (I) and [H₄tren](TaF₇)₂ (II). The structure determinations are performed by single crystal X-ray technique. Structures of I and II are built up from isolated TaF₇ distorted monocapped trigonal prisms or pentagonal bipyramids; charge balance is achieved by tetraprotonated [H₄tren]⁴⁺ cations which possess a “scorpion” configuration. In I and II, TaF₇ polyhedra, connected by hydrogen bonds with water molecules in I, lie in corrugated layers; hydrogen bond networks ensure the cohesion between these layers and [H₄tren]⁴⁺cations.     

Synthesis, crystal structure and thermal behavior of two hydrated forms of lanthanide phthalates Ln2(O2+C6H4-CO2)3(H2O) (Ln=Ce, Nd) and Nd2(O2C-C6H4-CO2)3(H2O)3

New hydrated lanthanide phthalates have been hydrothermally prepared with cerium and neodymium in different reaction media involving water or mixed water-ethanol solvent. The monohydrated Ln₂(1,2-bdc)₃(H₂O) (Ln=Ce or Nd) and dihydrated Nd₂(1,2-bdc)₃(H₂O)₂ forms have been characterized by single-crystal analysis. Their structures consist of infinite inorganic chains of lanthanide-centered polyhedra linked to each other through the phthalate ligands in order to generate mixed organic-inorganic layered structure. The two hydrated structures differ by the number of terminal water species attached to the lanthanide cations, which induce symmetry change from a triclinic (Nd₂(1,2-bdc)₃(H₂O)₂) to an orthorhombic (Nd₂(1,2-bdc)₃(H₂O)₂) cell for neodymium whereas the cerium-based phase only exists in the monohydrated form, with two distinct symmetries (orthorhombic or triclinic). Structural comparisons with the other members of the lanthanide phthalate series with identical chemical formula are also discussed. Thermal X-ray diffraction experiment indicates that the transformation from dihydrate form into the monohydrated form does not occur during a heating process.     

两个具stp三维拓扑构型的稀土配位聚合物{[Ln_2(pda)_3(H_2O)_2]·2H_2O}_n(Ln=Nd,La)

本文利用水热合成方法,将稀土氧化物与邻苯二乙酸(H2pda)反应得到了2个新颖的稀土配位聚合物{[Ln2(pda)3(H2O)2]·2H2O}n(Ln=Nd(1),La(2))。测定了它们的晶体结构,并进行了X-射线单晶衍射、红外光谱、荧光光谱和热重分析等性质的表征。晶体结构测定表明这2个化合物为异质同晶化合物。属单斜晶系,C2/c空间群。晶体学参数分别为配合物1:a=2.629 06(18)nm,b=1.611 72(11)nm,c=0.783 27(5)nm,β=93.173(5)°,V=3.313 9(4)nm3,Z=4,F(000)=1 840,μ=3.173 mm-1,Dc=1.878 g·cm-3,R1=0.022 6,wR2=0.060 9;配合物2:a=2.627 1(14)nm,b=1.614 9(8)nm,c=0.796 6(4)nm,β=92.850(9)°,V=3.375(3)nm3,Z=4,F(000)=1 816,μ=2.570 mm-1,Dc=1.823 g·cm-3,R1=0.0466,wR2=0.1416。化合物中邻苯二乙酸配体连接相邻的稀土金属离子,形成复杂的具有stp拓朴构型的三维网络结构。     

Syntheses and structures of three new scandium selenites: Sc2(SeO3)3·H2O, Sc2 (SeO3)3·3H2O and CsSc3(SeO3)4 (HSeO3)2·2H2O

Three new hydrated scandium selenites have been hydrothermally synthesized as single crystals and structurally and physically characterized. Sc₂(SeO₃)₃·H₂O crystallizes as a new structure type containing novel ScO₇ pentagonal bipyramidal and ScO₆₊₁ capped octahedral coordination polyhedra. Sc₂(SeO₃)₃·3H₂O contains typical ScO₆ octahedra and is isostructural with its M₂(SeO₃)₃·3H₂O (M=Al, Cr, Fe, Ga) congeners. CsSc₃(SeO₃)₄(HSeO₃)₂·2H₂O contains near-regular ScO₆ octahedra and has essentially the same structure as its indium-containing analogue. All three phases contain the expected pyramidal [SeO₃]^2- selenite groups. Crystal data: Sc₂(SeO₃)₃·3H₂O, M_r=524.85, trigonal, R3c (No. 161), , , , Z=6, R(F)=0.018, wR(F²)=0.036; Sc₂(SeO₃)₃·H₂O, M_r=488.82, orthorhombic, P2₁2₁2₁ (No. 19), , , , , Z=4, R(F)=0.051, wR(F²)=0.086; CsSc₃(SeO₃)₄(HSeO₃)₂·2H₂O, M_r=1067.60, orthorhombic, Pnma (No. 62), , , , , Z=4, R(F)=0.035, wR(F²)=0.070.     

High-temperature spin crossover in the [Fe(L)2][Fe(L)(NCS)3](NCS)·2H2O complex, L = tris(pyrazol-1-yl)methane

A novel iron(II) coordination compound with tris(pyrazol-1-yl)methane (L) of the composition [FeL₂][Fe(L)(NCS)₃](NCS)·2H₂O has been synthesized. Employing the XRD technique, its crystal structure has been determined. The compound was studied with the help of IR and UV-Vis spectroscopy and static magnetic susceptibility methods. A magnetochemical study of the complex within the temperature range 78-400 K has demonstrated that the compound exhibits a high-temperature spin crossover (SCO) ¹А₁ ⇔ ⁵Т₂. The transition temperature amounts to 380 K.     

Synthesis and crystal structure of Ru-supported tungstoantimonate [Sb2W20Ru2(H2O)2(dmso)6O68]

The first Ru^III-supported tungstoantimonate [Ru^II(bpy)₃]₂[Sb₂W₂₀Ru^III₂(H₂O)₂(dmso)₆O₆₈]·3dmso (bpy=bi-pyridine) (1a) has been successfully isolated as [Ru(bpy)₃]²⁺ (Rubpy) salt by routine synthetic reaction in mixed solutions with dmso and water. Single-crystal X-ray analysis was carried out on 1a, which crystallizes in the triclinic system space group P-1 with a=16.804 (6), b=16.988 (6), c=17.666 (6) Å, α=107.397 (13)°, β=106.883 (13)°, γ=103.616 (12)°. V=4309 (3) Å³, Z=1 with R1=0.0773. The compound 1a reveals the following features: (1) Rubpy is firstly used as an alternative ruthenium-source for the synthesis of Ru-substituted heteropolytungstate; (2) the structure of 1a consists of four Ru^III-O-S(CH₃)₂ and two W-O-S(CH₃)₂ bonds resulting in an assembly with C₂ symmetry; (3) the Ru^III ions are linked to two dmso groups via two Ru^III-O-S(CH₃)₂ bonds, which represents the other dmso-coordination mode to Ru^III in POM chemistry. The cyclic voltammetry studies of 1a in dmso/H₂SO₄ (3/1 v/v) at pH 2.5 medium using the glassy carbon electrode as a working electrode show the respective electrochemical behaviors of the W-centers and the Ru-centers within 1a, which could be separated clearly. In addition, the compound 1a exhibits photoluminescence arising from π*−t_2g ligand-to-metal transition of Rubpy.