New luminescent heteronuclear Ln(III)–Bi(III) complexes (Ln = Nd,Eu, Tb,Yb) based on aminopolycarboxylic acids

New heteronuclear Ln(III)–Bi(III) complexes (Ln?=?Nd, Eu, Tb, Yb, Lu) with ethylenediamine-N,N,N′,N′-tetraacetic (H₄edta), trans-1,2-cyclohexane-diamine-N,N,N′,N′-tetraacetic (H₄cdta), diethylenetriamine-N,N,N′,N″,N″-pentaacetic (H₅dtpa), and triethylenetetraamine-N,N,N′,N″,N″′,N″′-hexaacetic (H₆ttha) acids have been synthesized with a different synthetic approach. Bi(III) is a sensitizer of the 4f-luminescence in visible and near IR region. Emission spectra of Eu(III)–Bi(III) complexes were studied and the asymmetry of Eu(III) coordination environment was estimated, in good agreement with molecular models. The complexes synthesized by self-assembly are characterized by higher values of the 4f-luminescence quantum yield than other Ln(III)–Bi(III) complexes.     

A series of heterobimetallic Ni(II)–Ln(III) (Ln = La,Ce, Pr and Nd) coordination polymers derived from 3-EtOsalamo and dicarboxylates: syntheses,crystal structures and fluorescence properties

Transition Metal Chemistry - Four coordination polymers ∞2 [Ni(DMF)(L)Ln(bdc)1.5] (Ln?=?La (1) and Nd (4)) and ∞2 [Ni2(DMF)2(L)2Ln2(bdc)3]·CH3OH (Ln?=?Ce...     

Synthesis, structures, and photoluminescence of heteroligand complexes Ln(L)(iso-Bu2PS2)2(NO3) (Ln = Sm, Tb, Dy; L = Phen, 2,2′-Bipy)

Heteroligand complexes Ln(L)(iso-Bu₂PS₂)₂(NO₃) (Ln = Sm, Tb, Dy; L = Phen, 2,2??-Bipy) (I?CVI) are synthesized. The structure of Dy(Phen)(iso-Bu₂PS₂)₂(NO₃) (III) is determined from the data of X-ray structure analysis. The crystal structure of complex III is based on discrete mononuclear molecules in which the Dy atom has distorted dodecahedral coordination (polyhedron N₂O₂S₄). The ligands Phen, iso-Bu₂PS ₂ ^? and NO ₃ ^? are bidentate-cyclic. According to the X-ray diffraction analysis data, complexes I and II are isostructural to compound III. Complexes I?CVI have photoluminescence in the visible spectral range. The photoluminescence spectra of solid samples of compounds I?CVI exhibit bands corresponding to the radiative electron transitions of the Sm³⁺, Tb³⁺, and Dy³⁺ ions. Among the studied compounds I?CVI, the Tb(III) complexes are characterized by the most intense photoluminescence.     

Crystal structure of compounds [Ln(H2O)8]3+·4CCl3COO?·4H2O·2(4-bpy)·(4-bpyH)+(Ln(III) = Gd, Tb, Er, AND Tm)

Novel compounds of Gd(III), Tb(III), Er(III), and Tm(III) with 4,4??-bipyridine (4-bpy) and trichloroacetates are prepared. The title compounds are isomorphic and isostructural in the solid state. All atoms in the studied compound lie in general positions of the Cc space group. The coordination polyhedra around central atoms can be described as bicapped trigonal prisms slightly disordered towards a square antiprism. All 4-bpy molecules are located in the outer coordination sphere together with four trichloroacetate anions and four water molecules. One of the nitrogen atoms of one 4-bpy is protonated due to stoichiometry.     

Syntheses,structures, and properties of transition metal complexes with 2-( n -pyridyl)benzimidazole ( n = 2, 3, and 4)

Three pyridylbenzimidazoles (2-PBIM, 3-PBIM, and 4-PBIM) have been prepared (2-PBIM: 2-(2-pyridyl)-benzimidazole, 3-PBIM: 2-(3-pyridyl)-benzimidazole, 4-PBIM: 2-(4-pyridyl)-benzimidazole). Reactions of several transition metals (Cd²⁺, Cu²⁺, Fe²⁺) with the three ligands gave four new coordination complexes, [(Cd)₂(2-PBIM)₂(CH₃COO)₄] (1), [Cu(3-PBIM)₂(CH₃COO)₂]?·?2H₂O (2), [Cu(4-PBIM)₂(CH₃COO)₂(H₂O)]?·?H₂O (3), and [Fe(4-PBIM)₂(Cl)₂(H₂O)₂] (4), respectively. These four complexes have been characterized by X-ray crystallography, IR spectroscopy, and UV absorption spectroscopy. Thermogravimetric properties of 2 and 4 were also measured. X-ray crystallographic studies reveal that these four complexes are very different, although the ligands are similar in structure. The role of hydrogen-bonding and π–π interactions in extending dimensionality of simple complexes has been discussed.     

Thermal decomposition of double rare earth(III) monomethylammonium sulfates with general empirical formula CH3NH3Ln(SO4)2·3H2O (Ln=La-Er and Y)

Double rare earth(III) monomethylammonium sulfates with general empirical formula CH₃NH₃Ln(SO₄)₂·3H₂O (Ln = La-Er and Y) were synthesized and examined by X-ray powder diffraction, TG, DTG and DTA in the temperature range from 25° to 700°C, and chemical analysis. It was found that these compounds are isomorphous and decompose to rare earth sulfate at 700°C.The authors are grateful to the Research Council of Slovenia for financial support of this research.     

三元体系Ln(ClO4)3-4-ClCH2COAp-H2O(30℃)的相平衡研究(Ln=La,Sm,Er)

我们测定了三元体系Ln(ClO4)3-4-ClCh2COAp-H2O(Ln=La,Er)在30℃时的溶度及饱和溶液的折光指数,绘制相应的溶度图和饱和溶液的折光指数曲线图。体系的溶度曲线和折光指数曲线均由四支组成,分别与4-ClCh2COAp、Ln(4-ClCh2COAp)3·nH2O(Ln=La,n=7;Sm,8;Er,4)、Ln(4-ClCH2COAp)2(ClO4)3·nH2O(Ln-La,n=7;Sr,6;Er,4)和Ln(ClO4)3·nH2O(Ln=La,n=8;Sm,9;Er,6)相对应,两类配合物均为固液异组成化合物。     

A self assembled 3-D network propagated by coordination polymerization and H-bonding: synthesis and X-ray crystal structure of [{Co(L)2(H2O)2}(ClO4)2(CH3COCH3)2(H2O)2] n,where L = N,N-diisopropylisonicotinamide

Reaction of Co(ClO₄)₂?·?6H₂O with N,N-diisopropylisonicotinamide (L) has yielded a 1-D coordination polymer [{Co(L)₂(H₂O)₂}(ClO₄)₂(CH₃COCH₃)₂(H₂O)₂] _n (1). Complex 1 has been characterized by infrared (IR) and UV-Vis spectroscopies, thermal analysis, and single crystal X-ray diffraction techniques. The structure has alternate arrangement of parallel 1-D cationic metal-ligand chains and H-bonded anionic chains containing perchlorate, acetone and water in the lattice. Further hydrogen bonding among both chains leads to formation of 2-D networks along almost perpendicular planes. Interpenetrations of such perpendicular 2-D sheets create a 3-D supramolecular structure.     

三元体系Ln(ClO4)3-4-ClCH2COAp-H2O(30℃)的相平衡研究(Ln=La,Sm,Er)

我们测定了三元体系 Ln(ClO_4)_3—4-ClCH_2COA_p—H_2O(Ln=La,Sm,Er)存30℃时的溶度及饱和溶液的折光指数,绘制了相应的溶度图和饱和溶液的折光指数曲线图.体系的溶度曲线和折光指数曲线均由四支组成,分别与4-ClCH_2COA_p、Ln(4-ClCH_2COAp)_3(ClO_4)_3·nH_2O(Ln=La,n=7;Sm,8;Er,4)、Ln(4-ClCH_2COAp)_2(ClO_4)_3·nH_2O(Ln=La,n=7;Sm,6;Er,4)和 Ln(ClO_4)_3·nH_2O(Ln=La,n=8;Sm,9;Er,6)相对应,两类配合物均为固液异组成化合物.     

First-principles calculations on the structures,magnetic, and electronic properties of the (Fe2N)m (m = 1–4) and (Fe3N)n (n = 1–3) clusters

The structures, magnetic, and electronic properties of the ground-state (Fe₂N)_m (m?=?1–4) and (Fe₃N)_n (n?=?1–3) clusters have been investigated by using first-principles. The structure of the (Fe₂N)_m and (Fe₃N)_n clusters is a compromise that the N atoms approach more Fe atoms and the N atoms repel each other. The structural stabilities of the (Fe₂N)_m and (Fe₃N)_n clusters increase with the increasing of the N ratio except for the Fe₆N₃ clusters. The (Fe₂N)_m (m?=?1–4) and Fe₉N₃ clusters exhibit more kinetic stabilities than pure iron clusters. The N substitution can decrease the average spin densities of small iron clusters except for the Fe₆N₂ and Fe₈N₄ clusters. The Fe–N bonds exhibit certain covalent bond characteristics.

     

Structures,electronic and magnetic properties of the FemOn@Cx (m = 1–3, n = 1–4, x = 50, 60) clusters

The structures, electronic and magnetic properties of the Fe_mO_n@C_x (m?=?1–3, n?=?1–4, x?=?50, 60) clusters have been investigated by using PBE functional. The C₅₀, C₆₀ can significantly increase the structural stabilities of the Fe_mO_n molecules. Fe₂O₃@C₅₀ and Fe₃O₄@C₅₀ are more chemically stable than the Fe₂O₃@C₆₀ and Fe₃O₄@C₆₀ while FeO@C₆₀ is more chemically stable than the FeO@C₅₀. The spin densities of the Fe_mO_n fragments degenerate to zero. Carbon encapsulation leads to the internal charges of the Fe_mO_n fragments transfer from 4 s to 4p orbital.

     

Hydrothermal Synthesis,Crystal Structures,and Fluorescence Properties of Ni(II)–Ln(III) Complexes (Ln = Sm,Pr, Eu)

Three novel 3d–4f heterometal complexes [Ln(NiL)₃(Btca)(NO₃)] · xH₂O (Ln = Sm(III) (I), Pr(III) (II), Eu(III) (III) (H₂L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H₂Btca = benzotriazole-5-carboxylic acid) were solvothermally synthesized and characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1555557 (I), 1555555 (II), 1555556 (III)). They crystallized in the monoclinic space group P2₁/n for I (x = 1.5) and C2/c for (II) and (III) (x = 1), respectively. In these complexes, the central Ln(III) and external nickel ions are bridged by macrocyclic oxamide groups. The metal center of Ln(III) resides in a distorted bicapped square antiprism surrounding with six oxygen atoms of three oxamide groups, two oxygen atoms of Btca^2– ion and two oxygen atoms of NO₃^-. Furthermore, there are C–H···O and/or C–H···N hydrogen bond interactions among nitrate, benzotriazole-5-carboxylate, macrocyclic oxamide and water to form three-dimensional superamolecular architecture. The fluorescence properties of the compounds I and II are also discussed.     

Complexation of Sc(III), Ga(III), In(III) and Ln(III) with Eriochrome Red B

Cyclic linear-sweep voltammetry was used to study the complexation of Sc(III), Ga(III), In(III) and Ln(III) with eriochrome red B (ERB). It was established that all metal ions investigated form complex compounds with azodye having a mole ratio, M(III):ERB = 1:2. The hydroxo forms of M(III) ions, which take part in interaction with ERB, were determined by the Nazarenko method. The stability constants for the formation of these chelates are nearly the same. It was shown that the reduction of the ligand in the complex does not only depend on the peculiarities of complexation, but the processes occurring in pre-electrode layer also influence it.     

Co(III) and Cr(III) complexes of diphosphadithia ligands and the crystal structure of [CoCl2(L3)]PF6·CH2Cl2 (L3=Ph2P(CH2)2S(o-C6H4)S(CH2)2PPh2)

[CrX₃(thf)₃] (X=Cl or Br) reacts with L (L=L¹–L³ or Ph₂[14]aneP₂S₂) (L¹=Ph₂P(CH₂)₂S(CH₂)₂S(CH₂)₂PPh₂, L²=Ph₂P(CH₂)₂S(CH₂)₃S(CH₂)₂PPh₂, L³=Ph₂P(CH₂)₂S(o-C₆H₄)S(CH₂)₂PPh₂, Ph₂[14]aneP₂S₂=4,8-diphenyl-1,11-dithia-4,8-diphosphacyclotetradecane) and TlPF₆ in MeNO₂ solution to yield the distorted octahedral complexes [CrX₂(L)]PF₆ as green coloured solids in high yield. UV/visible spectroscopy suggests that these are cis-dihalo species and they have also been characterised by IR spectroscopy, electrospray mass spectrometry and microanalyses. The Co(III) analogues [CoX₂(L)]⁺ are readily prepared in a two-stage reaction, involving treatment of CoX₂·6H₂O with L (L=L¹–L³) and NH₄PF₆ in EtOH solution to give a green/brown solid, followed by halogen oxidation of this product in CH₂Cl₂ solution using X₂/CCl₄, to give the final products as brown coloured solids. A mixture of PF₆⁻ and [CoX₄]²⁻ anions are present in the final Co(III) compounds in varying ratios. Crystal structures of [CoCl₂(L²)]₂[CoCl₄]·4H₂O and [CoCl₂(L³)]PF₆·CH₂Cl₂ confirm tetradentate P₂S₂ coordination of L in each case, with mutually cis halogens completing the distorted octahedral geometry. In both cases the complex cation adopts the cis-α form in the solid state and this is also consistent with the solution ³¹P{¹H} NMR spectroscopic data. ⁵⁹Co NMR spectroscopy reveals a very broad single resonance at ≈3200 ppm for these species.     

Thermal decomposition of Ln(C2H5CO2)3·H2O (Ln?=?Ho, Er, Tm and Yb)

The thermal decomposition of Ho(III), Er(III), Tm(III) and Yb(III) propionate monohydrates in argon was studied by means of thermogravimetry (TG), differential thermal analysis (DTA), IR-spectroscopy and X-ray diffraction (XRD). Dehydration takes place around 90?°C. It is followed by the decomposition of the anhydrous propionates to Ln₂O₂CO₃ (Ln?=?Ho, Er, Tm or Yb) with the evolution of CO₂ and 3-pentanone (C₂H₅COC₂H₅) between 300 and 400?°C. The further decomposition of Ln₂O₂CO₃ to the respective sesquioxides Ln₂O₃ is characterized by an intermediate plateau extending from approximately 500?C700?°C in the TG traces. This stage corresponds to an overall composition of Ln₂O_2.5(CO₃)_0.5 but is more probably a mixture of Ln₂O₂CO₃ and Ln₂O₃. The stability of this intermediate state decreases for the lighter rare-earth (RE) compounds studied. Full conversion to Ln₂O₃ is achieved at about 1,100?°C. The overall thermal decomposition behaviour of the title compounds is similar to that previously reported for Lu(C₂H₅CO₂)₃·H₂O.     

Predictable self-assembled [2×2] Ln(III)4 square grids (Ln = Dy,Tb)-SMM behaviour in a new lanthanide cluster motif

The ditopic carbohydrazone ligand (L1) produces the square, self-assembled [2×2] grids [Dy(4)(L1)(4)(OH)(4)]Cl(2) (1) and [Ln(4)(L1)(4)(μ(4)-O)(μ(2)-1,1-N(3))(4)] (Ln = Dy (2), Tb (3)), with 2 exhibiting SMM behaviour. Two relaxation processes occur with U(eff) = 51 K, 91 K in the absence of an external field, and one with U(eff) = 270 K in the presence of a 1600 Oe optimum field.     

三元体系Ln(ClO~4)~3-ACAP-H~2O(Ln=La,Sm,Yb)的相平衡研究(30℃)

测定了三元体系Ln(ClO~4)~3-ACAP-H~2O(Ln=La,Sm,Yb, ACAP=4-乙酰安替比林)在30℃时的溶解度及饱和溶液的折光率,绘制了相应的溶度图和饱和溶液的折光率-组成图.体系的溶度曲线和折光率曲线均由三支组成,分别与ACAP,Ln(ACAP)~3(ClO~4)~3·nH~2O(Ln=La,n=4,Sm,2,Yb,2)和Ln(ClO~4)~3·nH~2O(Ln=La,n=8,Sm,9,Yb,8)相对应.从溶度图上发现了三个未见文献报道的三元化合物, 它们均为固液异组成溶解的化合物.通过化学分析,元素分析,TG-DTG,IR,UV和X射线粉末衍射进行了表征.初步探讨了影响安替比林4位酰代衍生物β-二酮配体配位能力的因素