New pentafluorothiophenoxo derivatives of tin,lead, antimony,bismuth, gold and platinum

Summary Salts of the anions [SnX₅]^–, [SnX₄Cl, [SnX₃Cl₂]^–, [SnX₃]^–, [PbX₃]^–, [SbX₄]^–, [SbX₃Cl]^–, [SbX₂Cl₂]^–, [BiX₄]^–, [AuCl₂]^–, [AuX₂]^–, [AuXCl]^–, [AuX₄]^–, [Au₂X₆]^2– and [PtX₄]^2–, where X^– = C₆F₅S^–, have been isolated and characterised. The neutral SbX₃ and BiX₃ species, have also been isolated and shown to be pyramidal monomers (¹⁹F.n.m.r., i.r., and Raman spectral evidence). Various physical properties of the complexes prepared, as well as their stereochemistries (where these could be ascertained), are similar to those of the known corresponding halogeno compounds of these elements. These results further demonstrate the pseudo-halide nature of the pentafluorothiophenoxide ion.Author to whom all correspondence should be directed at: Laboratoire de Chimie de Coordination, Uniyersité Louis Pasteur, 67008 Strasbourg, France.     

Synthesis, characterization, and reactivity of half-sandwich Ru(II) complexes containing phosphine, arsine, stibine, and bismutine ligands

The synthesis and some reactions of the Ru(II) and Ru(IV) half-sandwich complexes [RuCp(EPh₃)(CH₃CN)₂]⁺ (E=P, As, Sb, Bi) and [RuCp(EPh₃)(η³-C₃H₅)Br]⁺ have been investigated. The chemistry of this class of compounds is characterized by a competitive coordination of EPh₃ either via a RuE or a η⁶-arene bond, where the latter is favored when the former is weaker, that is in going down the series. Thus in the case of Bi, the starting material [RuCp(CH₃CN)₃]⁺ does not react with BiPh₃ to give [RuCp(BiPh₃)(CH₃CN)₂]⁺ but instead gives only the η⁶-arene species [RuCp(η⁶-PhBiPh₂)]⁺ and [(RuCp)₂(μ-η⁶,η⁶-Ph₂BiPh)]²⁺. Similarly, the EPh₃ ligand can be replaced by an aromatic solvent or an arene substrate. Thus, the catalytic performance of [RuCp(EPh₃)(CH₃CN)₂]⁺ for the isomerization of allyl-phenyl ethers to the corresponding 1-propenyl ethers is best with E=P, while the conversion drops significantly using the As and Sb derivatives. By the same token, only [RuCp(PPh₃)(CH₃CN)₂]⁺ is stable in a non-aromatic solvent, whereas both [RuCp(AsPh₃)(CH₃CN)₂]⁺ and [RuCp(SbPh₃)(CH₃CN)₂]⁺ rearrange upon warming to [RuCp(η⁶-PhEPh₂)]⁺ and related compounds. In addition, the potential of [RuCp(EPh₃)(CH₃CN)₂]⁺ as precatalysts for the transfer hydrogenation of acetophenone and cyclohexanone has been investigated. Again aromatic substrates are clearly less suited than non-aromatic ones due to facile η⁶-arene coordination leading to catalyst's deactivation.     

Laboratory investigations of negative ion molecule reactions of propionic,butyric, glyoxylic,pyruvic, and pinonic acids

We have carried out laboratory measurements of gas-phase ion-molecule-reactions of several negative ion species with propionic, butyric, glyoxylic, pyruvic, and pinonic acids. A flow reactor operating at a temperature of 293 ± 3 K and total gas pressures of 1.5 hPa, 9 hPa, or 40 hPa were used. The negative reagent ion species investigated included CO₃⁻, CO₃⁻H₂O, NO₃⁻, NO₃⁻H₂O, NO₂⁻, NO₂⁻H₂O, and O₃⁻. The reactions were found to proceed either via proton transfer, switching, or clustering. A new proton transfer channel leading to alkylperoxy carboxylate radicals (R_−H(OO·)COO⁻) was observed for propionic, butyric, and pinonic acids.     

Coordinate Structures of PrIII, GdIII, TmIII, and YbIII Complexes with Nitrilotriacetic Acids

The crystal and molecular structures of the [Pr^III(nta)(H₂O)₂]·H₂O (nta = nitrilotriacetic acids), K₃[Gd^III(nta)₂(H₂O)]·6H₂O, and K₃[Yb^III(nta)₂]·5H₂O complexes have been determined by single-crystal X-ray structure analyses. In [Pr^III(nta)(H₂O)₂]·H₂O, the Pr^IIINO₈ part forms a nine-coordinate pseudo-monocapped square antiprismatic structure in which one N and three O atoms are from one nta ligand in the same molecule, three O atoms from another nta ligand in the neighboring molecule and two O atoms from two coordinate water molecules. In K₃[Gd^III(nta)₂(H₂O)]·6H₂O, the [Gd^III(nta)₂(H₂O)^3- complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which each nta acts as a tetradentate ligand with one N atom of the amino group and three O atoms of the carboxylic groups. In K₃[Yb^III(nta)₂]·5H₂O, each nta also acts as a tetradentate ligand with one N atom of amino group and three O atoms of the carboxylic groups, but the [Yb^III(nta)₂ ^3- complex anion has an eight-coordinate structure with a distorted square antiprismatic prism. All the results including those for [Tm^III(nta)(H₂O)₂]·2H₂O confirm the inferences on the coordinate structures and coordination numbers of rare earth metal complexes with the nta ligand.     

Organometallic gold(I)-pentafluorophenyl-P,O, As,S, TPA,dppm, dppe,dppa-coordinating-phosphines: synthesis and detailed spectroscopic characterisation

[Au(C₆F₅)(tht)], which on reaction with P, O, S-coordinating phosphines in CH₂Cl₂ medium leads to [Au(C₆F₅)(X)] [X = PPh₃ H, (1a), oMe, (1b), pMe, (1c), mMe, (1d), AsPh₃ (2), OPPh₃ (3), SPPh₃ (4), dppm, dppe, dppa = diphenylphosphino-methane,-ethane,-ammine(5, 6, 7), TPA = 135-tetraaza-7-phosphino adamentane(8), Py4H (9a), 4Bu (9b), 4Ac (9c), tht = tetrahydrothiophen, C₆F₅ is the pentafluorophenyl ring]. The maximum molecular peak of the corresponding molecule is observed in the ESI mass spectrum. I.r. spectra of the complexes show –C = C– and C₆F₅ stretching near at 1610 and 1510, 955, 800 cm⁻¹. The ¹H-n.m.r. spectra as well as ³¹P- (¹H)n.m.r. suggest solution stereochemistry, proton movement, phosphorus proton interaction. ¹³C-n.m.r. spectrum reflect the carbon skeleton in the molecule. In the ¹H–¹H COSY spectrum of the present complexes and contour peaks in the ¹H–¹³C-HMQC spectrum, assign the solution structure and stereoretentive conformation in each step.     

The ethyl halides: Stable neutral and radical cation isomers [C2, H2, X] where X = F,Cl, Br,I

The following isomers of the ethyl halide molecular ions have all been shown to be stable species in the gas phase: [CH₂CH₂FH]⁺˙; [CH₃ClCH₂]⁺˙ (ΔH_f° = 1012 kJ mol^?1); [CH₃CHClH]⁺˙ (ΔH_f° = 971 kJ mol^?1); [CH₂CH₂ClH]⁺˙; [CH₃BrCH₂]⁺˙ (ΔH_f° = 1058 KJ mol^?1); [CH₃CHBrH]⁺˙ (ΔH_f° = 995 kJ mol^?1) and [CH₂CH₂BrH]⁺˙. Neutralization–reionization mass spectrometry, employing Xe as the electron transfer target gas and O₂ as the target gas for reionization, indicated that the ylides CH₃ClCH₂ and CH₃BrCH₂ could not be generated by such means. However, the species CH₃CHClH, CH₂CH₂ClH and CH₂CH₂BrH (and possibly CH₃CHBrH) were unambiguously identified.     

Synthese und Charakterisierung von Tetrabromoferraten(III) AFeBr4 mit einwertigen Kationen A  Cs,Rb, Tl,NH4, K,Na, Li,Ag

Preparation and Characterization of Tetrabomoferrates(III) AFeBr₄ with Monovalent Cations A ? Cs, Rb, Tl, NH₄, K, Na, Li, Ag Tetrabromoferrates(III) AFeBr₄ of the monovalent cations A ? Cs, Rb, Tl, NH₄, Na, Ag, Li have been prepared in closed ampoules by reaction of the appropriate bromides with iron and an excessive amount of bromine. The dark red compounds were characterized by DTA, Raman spectroscopy and X-ray powder diffraction. Their crystal structures have been assigned to five structure types, containing FeBr₄ anions. The coordination number runs from 12 (Cs⁺, Rb⁺) over 10 (NH₄⁺) and 8 (K⁺), to 6 (Na⁺, Ag⁺, Li⁺). Lattice parameters for all compounds see “Inhaltsübersicht”. CsFeBr₄ and RbFeBr₄ crystallize orthorhombic in the BaSO₄-type, NH₄FeBr₄ monoclinic in the KAlBr₄-type, KFeBr₄ orthorhombic in the GaGaCl₄-type, NaFeBr₄ monoclinic in the NaGaBr₄-type, AgFeBr₄ and LiFeBr₄ monoclinic in the LiAlCl₄-type, while the structure of TlFeBr₄ is still unknown.     

Wave mechanics - the first fifty years : edited by W.C. Price,S.S. Chissick and T. Ravensdale,Butterworths, London, 1973, pp. 435, price £12.00

The free NH₃ molecule and the [Zn(NH₃)₄]²⁺ ion were studied by the kinematic coupling approach. The pure effects of this coupling were found to be small, and some modifications had to be introduced in order to get a reasonable force field. The force constants deduced for the skeletal vibrations are comparable with those of a quasi-exact force field. Calculated frequencies for [⁶⁸Zn(NH₃)₄]²⁺ and [⁶⁴Zn(ND₃)₄]²⁺ are reported in addition to those of [⁶⁴Zn(NH₃)₄]²⁺. Mean amplitudes of vibration for [⁶⁴Zn(NH₃)₄]²⁺ are given.     

A 2D cadmium metal–organic framework: Synthesis,structure and luminescence sensing for chromate,permanganate, cupric,silver and ferric

A multi-responsive Cd metal–organic framework {[Cd (ttpe)(H₂O)(ip)]•4H₂O•DMAC}_n ( 1•4H ₂ O•DMAC ) was synthesized using hydrothermal method (ttpe = 1,1,2,2-tetra(4-(1H-1,2,4-triazol-1-yl)phenyl)ethylene, ip = isophthalate, DMAC = N,N-dimethylacetamide), and characterized. 1 exhibits a 2D (4,4) network. The luminescent sensing experimrnts showed that 1•4H ₂ O•DMAC as a new MOF luminescent sensor can detect Cr₂O₇²⁻, CrO₄²⁻, MnO₄⁻, Cu²⁺, Ag⁺ and Fe³⁺ in aqueous solution with simultaneously high efficiency and high sensitivity. The quenching constants K_sv for Cr₂O₇²⁻, CrO₄²⁻, MnO₄⁻, Cu²⁺, Ag⁺ and Fe³⁺ are 4.231 × 10⁴ M⁻¹, 2.471 × 10⁴ M⁻¹, 6.459 × 10³ M⁻¹, 7.617 × 10³ M⁻¹, 1.563 × 10⁴ M⁻¹ and 3.574 × 10⁴ M⁻¹, respectively. The detection limits are 0.094 μM for Cr₂O₇²⁻, 0.108 μM for CrO₄^{2 −} , 0.346 μM for MnO₄⁻, 0.302 μM for Cu²⁺, 0.221 μM for Ag ⁺ , and 0.100 μM for Fe³⁺. 1•4H ₂ O•DMAC exhibits high photocatalytic efficiency for degradation of methylene blue under visible light irradiation.     

Conformational Heterogeneity in Diphthalocyaninato(2–)metallates(III) of Sc,Y, In,Sb, Bi,La, Ce,Pr, and Sm

Potassium diphthalocyaninato(2–)metallate(III), K[M(pc^2–)₂] (M = Bi, La, Ce, Pr, Sm, Sb, In) has been prepared by melting the metal chloride, iodide or acetate with 1,2‐dicyanobenzene in the presence of potassium methylate. Crystallisation with tetra(n‐butyl)ammonium bromide or hydroxide ((ⁿBu₄N)Br/OH), tetra(n‐pentyl)ammonium chloride ((ⁿPe₄N)Cl) or bis(triphenylphosphine)iminium halide ((PNP)X; X = Br, I) yields the corresponding red‐purple complex salt (ⁿBu₄N)[M(pc^2–)₂] (M = Bi ( 1 ), La ( 3 ), Ce ( 2 )), (ⁿBu₄N)[M(pc^2–)₂] · x CH₃OH (M = Bi ( 5 ), Pr ( 6 ), Sm ( 7 ); 0 9 x 9 1), (ⁿPe₄N)[La(pc^2–)₂] ( 4 ), (ⁿBu₄N)[Pr(pc^2–)₂] · 2 py ( 10 ), (ⁿBu₄N)[Sb(pc^2–)₂] · 2 thf ( 11 ), (PNP)₂[M(pc^2–)₂]Br · 2 Et₂O (M = Sb ( 12 ), Bi ( 13 )), and (PNP)₂[In(pc^2–)₂]I · 2 Et₂O ( 14 ). Bronze coloured diphthalocyaninato(1–)metal(III) polyiodide, [M(pc^–)₂]I₂ (M = Sc, Y) has been prepared similarly in the presence of ammonium iodide. Reduction with (ⁿBu₄N)OH provides (ⁿBu₄N)[M(pc^2–)₂] · x CH₃OH (M = Y ( 8 ), Sc ( 9 ); 0 9 x 9 1). Spectral properties (UV/VIS/NIR; IR; resonance Raman) of diphthalocyaninates in their different ring oxidation states (2–/2–; 2–/1–; 1–/1–) are discussed. 1 – 3 crystallise in the tetragonal (P4/ncc), 5 – 9 in the orthorhombic (Pna2₁), 10 , 11 in the triclinic (P‐1), and 4 , 12 – 14 in the monoclinic crystal system ( 4 : P2₁/m; 12 : C2/c; 13 , 14 : P2/c). Ecliptic rotamers with skew angles ranging from 4.1° to 6.0° are found in 1 – 3 , and staggered rotamers with skew angles ranging from 35.8° to 45.0° are found in 4 – 14 . The mean M–N_i bond lengths and interplanar distances increase monotonically with the ionic radius of the metal ion. Both distances deviate notably from this linear correlation in the Sb^III and Bi^III derivatives. The discrepancy is presumably due to the sterical dominance of the ns² lone‐pair character. The actual size of eight co‐ordinated Sb^III and Bi^III is estimated to be R₈ ≈ 1.02(Sb)/1.11(Bi) Å. In every complex salt, the pc ligand is severely distorted from planarity and can adopt domed, saddled, waved and mixed non‐planar conformations; the crystal symmetry is the most important factor for the conformational heterogeneity.     

Elusive Antimony‐Centered Radical Cations: Isolation,Characterization, Crystal Structures,and Reactivity Studies

One‐electron oxidation of the stibines Aryl₃Sb ( 1 , Aryl=2,6‐ⁱ Pr₂‐4‐OMe‐C₆H₂; 2 , Aryl=2,4,6‐ⁱ Pr₃‐C₆H₂) with AgSbF₆ and NaBAryl^F₄ (Aryl^F=3,5‐(CF₃)₂C₆H₃) afforded the first structurally characterized examples of antimony‐centered radical cations 1 ^.+[BAryl^F₄]⁻ and 2 ^.+[BAryl^F₄]⁻. Their molecular and electronic structures were investigated by single‐crystal X‐ray diffraction, electron paramagnetic resonance spectroscopy (EPR) and UV/Vis absorption spectroscopy, in conjunction with theoretical calculations. Moreover, their reactivity was investigated. The reaction of 2 ^.+[BAryl^F₄]⁻ and p ‐benzoquinone afforded a dinuclear antimony dication salt 3 ²⁺[BAryl^F₄]₂⁻, which was characterized by NMR spectroscopy and X‐ray diffraction analysis. The formation of the dication 3 ²⁺ further confirms that the isolated stibine radical cations are antimony‐centered.     

Elusive Antimony‐Centered Radical Cations: Isolation,Characterization, Crystal Structures,and Reactivity Studies

One‐electron oxidation of the stibines Aryl₃Sb ( 1 , Aryl=2,6‐ⁱ Pr₂‐4‐OMe‐C₆H₂; 2 , Aryl=2,4,6‐ⁱ Pr₃‐C₆H₂) with AgSbF₆ and NaBAryl^F₄ (Aryl^F=3,5‐(CF₃)₂C₆H₃) afforded the first structurally characterized examples of antimony‐centered radical cations 1 ^.+[BAryl^F₄]⁻ and 2 ^.+[BAryl^F₄]⁻. Their molecular and electronic structures were investigated by single‐crystal X‐ray diffraction, electron paramagnetic resonance spectroscopy (EPR) and UV/Vis absorption spectroscopy, in conjunction with theoretical calculations. Moreover, their reactivity was investigated. The reaction of 2 ^.+[BAryl^F₄]⁻ and p ‐benzoquinone afforded a dinuclear antimony dication salt 3 ²⁺[BAryl^F₄]₂⁻, which was characterized by NMR spectroscopy and X‐ray diffraction analysis. The formation of the dication 3 ²⁺ further confirms that the isolated stibine radical cations are antimony‐centered.     

N-Silatranylmethyl Derivatives of Pyrrole,Indole, and Carbazole

Organosilicon derivatives of pyrrole, indole, carbazole, and 2-methylindole containing (MeO)₃SiCH₂, Et₃SiCH₂, or N(CH₂CH₂O)₃SiCH₂ group on the nitrogen atom were synthesized. Their structure and stereoelectronic parameters were studied by X-ray diffraction, ¹H, ^{1 3}C, ^{1 5}N, and ^{2 9}Si NMR, IR and UV spectroscopy, and dielcometry, as well as by quantum-chemical calculations.     

The mono-, sesqui-, and dibromides of indium: InBr,In2Br3, and InBr2

Of the four reduced indium bromides, InBr, In₂Br₃, InBr₂, and In₄Br₇, synthesis, crystal growth and structure determination of the first three is reported. InBr (orthorhombic), Cmcm, Z = 4, a = 446.6(1), b = 1236.8(2), c = 473.9(1) pm, V_m = 39.42(1) cm³ mol^?1) crystallizes with the TlI-type structure. In₂Br₃ (orthorhombic, Pnma, Z = 16, a = 1300.6(5), b = 1649.8(5), c = 1289.7(9) pm, V_m = 104.16(9) cm³ mol ^?1), isotypic with Ga₂Br₃, is according to In₂[In₂Br₆] a mixed-valence In^I–In^II-bromid with eclipsed [In₂Br₆]^2? groups with d(In–In) = 268.8 and 271.6 pm, respectively. InBr₂(?In[InBr₄]) is a mixed-valence In^I? In^III bromide with the GaCl₂-type structure (orthorhombic, Pnna, Z = 8, a = 798.6(2), b = 1038.5(2), c = 1042.5(5) pm, V_m = 65.09(4) cm³ mol^?1).     

Synthesis,characterization, thermal,and antimicrobial studies of binuclear metal complexes of sulfa-guanidine Schiff bases

A series of metal complexes of Schiff bases derived from condensation of sulfa-guanidine with 1-benzoylacetone (H₂L¹), 2-hydroxybenzophenol (H₂L²), dibenzoylmethane (H₂L³), 5-methylisatine (H₂L⁴), and 1-methylisatine (H₂L⁵) have been synthesized. The complexes are characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, UV–Vis, ¹H NMR, and ESR spectra, as well as thermogravimetric analysis. The low molar conductance values indicate the complexes are nonelectrolytes. IR and ¹H NMR spectra show that H₂L¹–H₂L⁵ are coordinated to metal ions by two bidentate centers. Mn(II), Co(II), Ni(II), and Cu(II) complexes display paramagnetic behavior, whereas the Zn(II)-complex was diamagnetic. All studies confirm the formation of an octahedral geometry for [Cu₂L¹(AcO)₂(H₂O)₆] · 3H₂O (1), [Mn₂L⁴(AcO)₂(H₂O)₆] · 2H₂O (6), [Ni₂L⁴(AcO)₂(H₂O)₆] · 2H₂O (8), a tetrahedral geometry for [Cu₂L²(AcO)₂(H₂O)₂] (2), [Cu₂(L⁴)₂] (4), [Co₂(L⁴)₂] · 2H₂O (7) and [ZnHL⁴(AcO)(H₂O)] · 2H₂O (9) and a trigonal bipyramid geometry for [Cu₂L³(AcO)₂(H₂O)₄] (3) and [Cu₂HL⁵(AcO)₃(H₂O)₃] · H₂O (5). H₂L⁴ was most effective on Gram negative, Gram positive bacteria, and fungi (diameters inhibition zone ranged between 10.5–27.5 mm) after 24 and 48 h, respectively. Complex 8 showed moderate antimicrobial activity. Its minimum inhibitory concentration (MIC) against Escherichia coli, Bacillus subtilis, Candida albicans and Aspargllus flavas was 20 mg L^–1. The compound proved to be of moderate toxicity and its LD₅₀ was 20 mg L^–1.     

Electrochemical Reduction of Pentafluorophenylxenonium, -diazonium, -iodonium, -bromonium,and -phosphonium Salts

Cyclic voltammetry measurements on pentafluorophenylonium compounds of [C₆F₅X]⁺ Y^– type with X = Xe, N₂, C₆F₅Br, C₆F₅I, and (C₆F₅)₃P were carried out. In these series [C₆F₅Xe]⁺ shows the lowest and [(C₆F₅)₄P]⁺ the highest reduction potential. One electron reduction of [C₆F₅Xe]⁺ and [C₆F₅N₂]⁺ followed by the loss of Xe or N₂, respectively, leads to the generation of the [C₆F₅] ^· radical. Favoured following reactions of the [C₆F₅] ^· radical are the abstraction of hydrogen from MeCN or dimerisation. After the first reduction step the other onium cations split off the pentafluorophenyl element molecule such as (C₆F₅)₃P, C₆F₅Br, or C₆F₅I, respectively. These molecules undergo further reductions. The low reduction potential of [C₆F₅Xe]⁺ is in contrast to former measurements on partially fluorinated or chlorinated phenylxenonium cations. A plausible explaination for the different behaviour of these Xe–C compounds in electrochemical reduction processes is given.     

Pulsed,Crossed, Supersonic Molecular Beam Studies of Refractory Atom Reactions

Dynamics of refractory atom reactions have been studied with a crossed beam apparatus combining two pulsed, supersonic molecular beam sources, a pulsed UV laser for creating the refractory atoms in the gas phase by laser ablation, and a pulsed dye laser to probe the reaction products by laser-induced fluorescence. Examples of the A1(²P_j) + O₂(X³∑_g)→ A10(X²∑⁺) + O(³P_j), Mg(¹S_o) + N₂O(X¹∑⁺) → MgO(X¹∑⁺,a³Π) + N₂(X¹∑_g⁺) andC(³P_j) + NO(X²Π_r) → CN(X²∑⁺) + 0(³P_j) systems are given. Comparisons with the studies performed using the conventional steady-state beam approach are made.     

Synthesis,Persistent Luminescence,and Thermoluminescence Properties of Yellow Sr3SiO5:Eu2+,RE3+ (RE=Ce,Nd, Dy,Ho, Er,Tm, Yb) and Orange‐Red Sr3−xBaxSiO5:Eu2+, Dy3+ Phosphor

Sunlight‐excitable orange or red persistent oxide phosphors with excellent performance are still in great need. Herein, an intense orange‐red Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ persistent luminescence phosphor was successfully developed by a two‐step design strategy. The XRD patterns, photoluminescence excitation and emission spectra, and the thermoluminescence spectra were investigated in detail. By adding non‐equivalent trivalent rare earth co‐dopants to introduce foreign trapping centers, the persistent luminescence performance of Eu²⁺ in Sr₃SiO₅ was significantly modified. The yellow persistent emission intensity of Eu²⁺ was greatly enhanced by a factor of 4.5 in Sr₃SiO₅:Eu²⁺,Nd³⁺ compared with the previously reported Sr₃SiO₅:Eu²⁺, Dy³⁺. Furthermore, Sr ions were replaced with equivalent Ba to give Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ phosphor, which shows yellow‐to‐orange‐red tunable persistent emissions from λ=570 to 591 nm as x is increased from 0 to 0.6. Additionally, the persistent emission intensity of Eu²⁺ is significantly improved by a factor of 2.7 in Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ (x=0.2) compared with Sr₃SiO₅:Eu²⁺,Dy³⁺. A possible mechanism for enhanced and tunable persistent luminescence behavior of Eu²⁺ in Sr_3?xBa_xSiO₅:Eu²⁺,RE³⁺ (RE=rare earth) is also proposed and discussed.     

The reaction energies of ethylene, CO, and N2 with proton, hydrogen atom, and hydride ion

It is shown by quantum chemical simulation (MP2/aug-cc-pVTZ) that the energy of addition of H⁺, H^·, and H^? decreases in the order ethylene, CO, and N₂. The energies of additions of CF₄, dimethyl ether, and BF₃ to the ions and radicals formed were calculated. Unlike the CH₃CH₂ ^? ion, the HCO^? ion can add exothermically not one, but two BF₃ molecules.     

Verbindungen des Typs MII3MIII(PO4)3 mit Eulytinstruktur (MII = Pb,Sr, Ba; MIII = La,Lanthanide, Y,Sc, Bi,In, TI)1

A number of new phosphates of the formula M^II₃M^III(PO₄)₃ has been prepared. They have the cubic structure of eulytite (Bi₄(SiO₄)₃). Obviously all combinations of the cations being specified in the title for M^II and M^III seem to be possible; moreover, Ca₃Bi(PO₄)₃ does exist. The ions M^II and M^III are distributed on the positions of Bi in a statistical manner. The peculiar dependence of the lattive constants of the lanthanide compounds Pb₃Ln(PO₄)₃ (including La) on the (Atomic number of the lanthanide ions suggests the conclusion that the small trivalent cations (r < 1 Å) do not have a close contact with the surrounding oxygen ions forming a distorted octahedron.