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1.
Synthesis and Constitution of Fluorothalenite‐Type (Y3F[Si3O10]) Fluoride catena‐ Trisilicates M3F[Si3O10] with the Lanthanides (M = Dy, Ho, Er) By the reaction of the sesquioxides M2O3 with the corresponding trifluorides MF3 (M = Dy, Ho, Er), SiO2 and CsCl as flux (molar ratio: 1 : 1 : 3 : 6; 700 °C, 7 d) in evacuated silica tubes and gastight sealed metal capsules made of platinum, niobium or tantalum, respectively, single crystals of the fluoride silicates M3F[Si3O10] (monoclinic, P21/n; Z = 4; M = Dy: a = 734.06(6), b = 1116.55(9), c = 1040.62(8) pm, β = 97.281(7)°; M = Ho: a = 730.91(6), b = 1111.68(9), c = 1037.83(8) pm, β = 97.238(7)°; M = Er: a = 727.89(6), b = 1107.02(9), c = 1035.21(8) pm, β = 97.209(7)°) were obtained. The most important building groups in the crystal structures of the thalenite type are “isolated” [FM3]8+ triangles and catena‐trisilicate anions [Si3O10]8–, which contain three [SiO4] tetrahedra linked to a chain fragment via common corners. This has the shape of a horseshoe where both the terminal tetrahedra show different conformations (eclipsed and staggered) relative to the central unit. Therefore a chelatizing coordination on the same M3+ cation via oxygen atoms of both terminal [SiO4] groups is possible. The narrow area of existence of these fluoride silicates within the lanthanide series will be discussed and structural comparisons with other catena‐trisilicates are presented.  相似文献   

2.
On Fluoride Sulfides (MFS) of the Lanthanides (M = La–Nd, Sm, Gd–Lu) with A‐ or PbFCl‐Type Crystal Structure By the reaction of the elemental lanthanides (M = La–Nd, Sm–Lu) with the respective trifluorides (MF3) and sulfur (S) in 2 : 1 : 3‐molar ratios at 850 °C, single‐phase fluoride sulfides of the composition MFS can be obtained in evacuated, gas‐tightly arc‐welded niobium or tantalum capsules within a few days. Exceptions are europium and ytterbium which do not react to form the corresponding fluoride sulfides under these conditions. However, at least YbFS becomes accessible through this method if platinum serves as container material. With sodium chloride (NaCl) as a flux, the formation of hydrolysis‐insensitive, platelet‐shaped A‐type single crystals with square cross‐section and the formula MFS (M = La–Nd, Sm, Gd–Er) is possible. These are very suitable for structure refinement from X‐ray diffraction data. In the PbFCl‐analogous crystal structures (tetragonal, P4/nmm, Z = 2; LaFS: a = 404.38(4), c = 700.41(7) pm; CeFS: a = 400.13(3), c = 696.20(5) pm; PrFS: a = 396.27(3), c = 692.72(5) pm; NdFS: a = 393.89(3), c = 691.58(5) pm; SmFS: a = 388.36(3), c = 687.95(5) pm; GdFS: a = 383.45(3), c = 685.18(5) pm; TbFS: a = 381.02(3), c = 683.86(5) pm; DyFS: a = 378.48(2), c = 682.51(4) pm; HoFS: a = 376.48(3), c = 681.92(5) pm; ErFS: a = 374.61(3), c = 681.34(5) pm), the M3+ cations are surrounded by nine anions (4 F and 5 S2–) as monocapped square antiprisms. The anions themselves exhibit tetrahedral (F) and square‐pyramidal (S2–) cationic coordination, respectively, according to the Niggli formula {(M3+)(F)4/4(S2–)5/5}. In the case of TmFS, YbFS, and LuFS under analogous conditions, the hexagonal B‐ or trigonal C‐type modifications form at first, which can be transformed eventually to the quenchable metastable tetragonal A‐type polymorphs (TmFS: a = 372.86(5), c = 681.15(8) pm; YbFS: a = 371.08(5), c = 680.93(8) pm; LuFS: a = 369.37(5), c = 680.76(8) pm) at high pressure (20–60 kbar).  相似文献   

3.
Sulfide Chlorides (MSCl) of the Light Lanthanides (M = La–Pr) The reactions of the light lanthanides (M = La–Nd) with sulfur and the respective trichlorides (MCl3) in evacuated silica tubes (850 °C, 7 d) yield single-phase sulfide chlorides of the composition MSCl when appropriate molar ratios (2 : 3 : 1) of the reactants (M : S : MCl3) are used. A slight excess of trichloride as a flux promotes the formation of lath-shaped transparent single crystals (colorless for M = La and Ce, apple-green for M = Pr) which prove to be water soluble and sensitive to hydrolysis. The crystal structure was determined from X-ray single-crystal data taking LaSCl (orthorhombic, Pbcm (no. 57), a = 680.22(5), b = 705.26(7), c = 4203.7(3) pm, Z = 24, R = 0.069, Rw = 0.043) as an example. According to Guinier powder data CeSCl and quickly quenched samples of PrSCl crystallize isotypically. Thus four crystallographically independent cations (M3+) are present, each coordinated by four S2– but differing in the number of their next Cl neighbors. The figures of coordination are completed by four Cl about M1 (square antiprism, CN = 8), by only two Cl about M2 (trigonal prism, CN = 6), and by three Cl each about M3 and M4 (capped trigonal prisms, CN = 7). Six crystallographically different anions, although indistinguishable by X-ray diffraction, exhibit coordination numbers of four (S2–, 3 ×) and three (Cl, 3 ×) with respect to the cations. So PbO-analogous layers of the composition [SM4/4]+ parallel (100) are formed and held together along [100] by alternatingly sheathed Cl layers.  相似文献   

4.
On Oxytellurides (M2O2Te) of the Early Lanthanides (M = La–Nd, Sm–Ho) with A- or anti -ThCr2Si2-Type Crystal Structure By reacting elementary lanthanide metal (M = La–Nd, Sm–Ho) with tellurium dioxide (TeO2) in a 2 : 1 molar ratio, it is possible to obtain pure and single-phase oxytellurides of the composition M2O2Te at 750 °C in evacuated silica tubes within a few days. When larger quantities of cesium chloride (CsCl) are added as flux, plate-like single crystals with square cross-section are formed which are not sensitive to hydrolysis and very suitable for crystal structure refinements from X-ray data. In the anti-ThCr2Si2 analogous crystal structure (tetragonal, I4/mmm, Z = 2; La2O2Te: a = 412.31(4), c = 1309.6(1) pm; Ce2O2Te: a = 408.17(4), c = 1294.7(1) pm; Pr2O2Te: a = 405.62(4), c = 1285.8(1) pm; Nd2O2Te: a = 403.08(4), c = 1277.1(1) pm; Sm2O2Te: a = 399.83(4), c = 1265.5(1) pm; Eu2O2Te: a = 397.56(4), c = 1257.9(1) pm; Gd2O2Te: a = 396.20(4), c = 1253.2(1) pm; Tb2O2Te: a = 393.89(4), c = 1245.4(1) pm; Dy2O2Te: a = 392.34(4), c = 1240.3(1) pm; Ho2O2Te: a = 390.57(6), c = 1239.0(3) pm) the M3+ cations are surrounded by nine anions (4 O2– und 4 + 1 Te2–) in the shape of a capped square antiprism. The anions show coordination numbers of four (O2–: tetrahedra) and eight plus two (Te2–: bicapped cubes) with respect to the cations. PbO-analogous square {[OM4/4]2}2+ triple layer slabs are present parallel (001), which originate through two-dimensional infinite linking of [OM4]10+ tetrahedra via two trans-orientated pairs of edges (i. e. four edges altogether). These cationic layers are piled alternatingly along [001] with likewise quadratic single layers of Te2– anions, which take care of the three-dimensional coherence as well as of the charge balance.  相似文献   

5.
The zinc(II) center in the molecule of [(C23H36N4O3)ZnCl]Cl·H2O is coordinated by four nitrogen atoms of HL (1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol) and one chloro anion. The coordination moieties are connected by hydrogen bonds to form a one‐dimensional structure. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

6.
Anhydrous perchlorates M(ClO4)3 (M = La, Ce–Er, Y) were obtained by drying the products formed in the reaction of the respective lanthanide oxide with perchloric acid (70%). According to X‐ray powder investigations, they all crystallize with the hexagonal space group P63/m isostructural with the hydrogensulfates of the lighter lanthanides. For the example of Pr(ClO4)3 a full profile Rietveld refinement based on X‐ray powder data has been undertaken successfully (a = 933.61(3) pm, c = 584.88(2) pm; Rp = 0.207, RBragg = 0.068). The structure of Er(ClO4)3 was refined from neutron diffraction data (a = 919.7(1) pm, c = 559.8(1) pm; Rp = 0.190, RBragg = 0.106). High temperature X‐ray powder investigations show that thermal expansion occurs mainly in the (001) plane while the c axis remains nearly constant.  相似文献   

7.
Are the ‘Textbook Anions’ O2?, [CO3]2?, and [SO4]2? Fictitious? Experimental second electron affinities are still unknown for the title anions. It will be shown by means of quantum chemical ab initio calculations that these dianions are unstable with respect to spontaneous ionization. They all must be designated as non-existent.  相似文献   

8.
A new four‐component synthesis of spiro[4H‐indeno[1,2‐b]pyridine‐4,3′‐[3H]indoles] and spiro[acenaphthylene‐1(2H),4′‐[4H‐indeno[1,2‐b]pyridines] by the reaction of indane‐1,3‐dione, 1,3‐dicarbonyl compounds, isatins (=1H‐indole‐2,3‐diones) or acenaphthylene‐1,2‐dione, and AcONH4 in refluxing toluene in the presence of a catalytic amount of pyridine is reported.  相似文献   

9.
HClO4‐SiO2, efficiently catalyzed the condensation of o‐aminophenols and 2‐bromo‐1‐aryl‐ethanones to yield 3‐aryl‐2H‐benzo[1,4]oxazines in good yields.  相似文献   

10.
Sm3Cl[SiO4]2: A Chlorine‐poor Chloride Orthosilicate of Samarium Pale yellow, plate‐like single crystals of Sm3Cl[SiO4]2 (orthorhombic, Pnma; a = 701.74(8), b = 1800.8(2), c = 626.63(7) pm; Z = 4) are obtained upon the reaction of SmCl3, Sm2O3 and SiO2 (”︁Kieselgel”︁”︁) in 1 : 4 : 6 molar ratios, most advantageously in the presence of substantial amounts of NaCl as fluxing agent, after seven days at 850 °C in evacuated silica ampoules. The B‐type crystal structure (isotypic with e. g. Yb3Cl[SiO4]2) contains discrete orthosilicate tetrahedra [SiO4]4– which form anionic double layers ({(Sm1)2[SiO4]2}2–) with (Sm1)3+. These are alternatingly sheethed along [010] with cationic monolayers ({(Sm2)Cl}2+) consisting of (Sm2)3+ and Cl. Both crystallographically independent Sm3+ cations exhibit coordination numbers of eight (Sm1: 1 Cl + 7 O; Sm2: 2 Cl + 6 O) with respect to the involved electronegative particles.  相似文献   

11.
Ternary Selenides of the Lanthanides with Alkali Metals: I. The Composition Cs3M7Se12 (M = Gd–Ho) When the lanthanides gadolinium, terbium, dysprosium and holmium are oxidized with selenium in a molar ratio of 2 : 3 in evacuated silica tubes (700 °C, 7 d) and CsCl is added, ternary cesium lanthanide selenides with the composition Cs3M7Se12 (M = Gd–Ho) readily form. Surplus CsCl as flux accelerates the crystallization of the yellow, transparent needles. Since these crystals are stable to hydrolysis, excess CsCl and the chloride by-products (e. g. Cs3MCl6) can be rinsed off easily with water. The crystal structure of the flanking representatives Cs3Gd7Se12 and Cs3Ho7Se12 (orthorhombic, Pnnm (no. 58), Z = 2; Cs3Gd7Se12: a = 1294.8(3), b = 2650.1(5), c = 419.36(9) pm, R1 = 0.098, wR2 = 0.173; Cs3Ho7Se12: a = 1280.4(3), b = 2621.2(5), c = 412.13(8) pm, R1 = 0.096, wR2 = 0.126) was determined and refined on the basis of X-ray data from single crystals. With the help of powder diffraction Cs3Tb7Se12 (a = 1289.4(1), b = 2640.3(2), c = 416.82(3) pm) and Cs3Dy7Se12 (a = 1285.3(1), b = 2631.5(2), c = 414.47(3) pm) were established to be isotypic. The four new compounds crystallize isostructurally with Cs3Y7Se12, so that a three-dimensional framework {[M7Se12]3–} of vertex- and edge-sharing [MSe6] octahedra is present. Wave-like, one-dimensional infinite ”︁triple-channels”︁ run through the structure along [001] which are filled with two crystallographically different Cs+ cations (CN(Cs1) = 7 + 1, CN(Cs2) = 6). Owing to much too close Cs+–Cs+ contacts only a semi-occupation is possible for the Cs2 position which the structure refinements inevitably prove.  相似文献   

12.
We conveniently coated silicotungstic acid (STA, H4[W12SiO40]) on amino‐functionalized Si–magnetite nanoparticles, as surface functionalization of magnetic nanoparticles is an excellent way for green and efficient catalysis. The nanoparticles were structurally characterized using various techniques. The catalytic activity and recyclability of the STA–amine–Si–magnetite nanoparticles were probed through synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives. The reaction proceeds smoothly to provide products in excellent yields and short reaction times. The catalyst could be readily recovered using a simple external magnet and reused several times without any significant loss in activity. Herein, we report a comparison of the activity of H4[W12SiO40] as a homogeneous and heterogeneous catalyst, the latter being found to be more efficient. The findings offer effective methods for environmentally friendly synthesis of pyrazolo[1,2‐b]phthalazinedione derivatives.  相似文献   

13.
Chemical and Cyclovoltammetric Investigation of the Redoxreactions of the Decahalodecaborates closo ‐[B10X10]2– and hypercloso ‐[B10X10]· – (X = Cl, Br)1). Crystal Structure Analysis of Cs2[B10Br10] · 2 H2O The oxidation of the decachloro‐closo‐decaborates(2–) Cs2[B10Cl10] or [Me4N]2[B10Cl10] with Tl(CF3COO)3 leads to the corresponding radical monoanion hypercloso‐[B10Cl10] · –, which was characterized by ESR and UV/Vis spectroscopy. [B10Cl10] · – does not dimerize like [B10H10] · – but it is reduced by acetonitrile to the dianion [B10Cl10]2–. Cs2[B10Cl10] reacts with stronger oxidation agents like CoF3 (in dichloromethane) or XeF2 (in perfluorhexane), respectively, to yield B9Cl9 and, in traces, B8Cl8. In opposite to this, the decabromoderivative Cs2[B10Br10] does not show any reaction with Tl(CF3COO)3 in acetonitrile or with CoF3 in CH2Cl2. The oxidation of the dianions [B10X10]2– (X = Cl, Br) was studied by electroanalytical methods (cyclic voltammetry, chronoamperometry, chronocoulometry). Formal potentials were determined for the two steps of the reaction, which do not seem to be affected by structural rearrangements. The crystal structure of Cs2[B10Br10] · 2 H2O was analyzed by single‐crystal X‐ray diffraction. Cs2[B10Br10] · 2 H2O crystallizes monoclinic (space group I2/a, (no. 15), Z = 8, a = 1361.54(9) pm, b = 1215.89(5) pm, c = 3108.4(2) pm, α = 90°, β = 97.916(8)°, γ = 90°). The closo‐cluster B10Br102– has a bicapped square antiprismatic structure with idealized D4d symmetry.  相似文献   

14.
Ternary Alkali Metal Transition Metal Acetylides A2MC2 with A = Rb, Cs, and M = Pd, Pt By the reaction of Rb2C2 and Cs2C2 with palladium or platinum powder in sealed glass ampoules at 653 K ternary acetylides A2MC2 (A = Rb, Cs; M = Pd, Pt) were obtained. Their crystal structures were solved and refined by means of X‐ray powder investigations (Na2PdC2 structure type, P 3 m1, Z = 1). The crystal structures are characterised by [M(C2)2/22–] chains separated by the alkali metals. Raman spectroscopic investigations revealed wave numbers of the C–C stretching vibrations between 1833 and 1842 cm–1, which are in good agreement with the results of the analogous sodium and potassium compounds.  相似文献   

15.
Molecules of the title compound, C16H14N2O, a potential plant‐growth regulator, are linked into chains by intermolecular C=O...H—N hydrogen bonds. These chains are weakly interconnected by π–π stacking interactions to form a three‐dimensional framework. A comparison of the geometric parameters of the title molecule and several related benzimidazoles and pyrrolidones is presented.<!?tpb=22pt>  相似文献   

16.
Salts of Halogenophosphoric Acids. XIX Formation and Identification of Stable Intermediates on the Reaction of Fluoride with Phosphorus Oxychloride By reaction of POCl3 with fluorides of tertiary amines in the presence of the free amines the oxo-fluorophosphates [F2P(O? O? PF5)]?, [OPF5]2?, and [OPF4]? are formed as intermediates on the way to [PF6]?. The compounds were characterized by NMR spectroscopy.  相似文献   

17.
Reactions of the Dielement Compounds R2E–ER2 [E = Ga, In; R = CH(SiMe3)2] with Lithium Phenylethynide – Formation of Adducts by Retention of the E–E Bonds Lithium phenylethynide reacted with the dielement compounds tetrakis[bis(trimethylsilyl)methyl]digallane(4) ( 2 ) and diindane(4) ( 3 ) as a Lewis‐base and gave by the addition of one ethynido ligand to one of the Lewis‐acidic central atoms the anionic adducts 4 and 5 with intact Ga–Ga and In–In single bonds. Thus, compounds were formed, in which tricoordinated, coordinatively unsaturated Ga or In atoms are neighbored to tetracoordinated, coordinatively saturated ones. The E–E bonds [255.83 pm in 4 (Ga–Ga) and 285.24 pm in 5 (In–In)] are only slightly lengthened compared to those of the starting compounds 2 and 3 . A dynamic behavior with a fast change of the position of the ethynido ligand was observed for both compounds in solution at room temperature.  相似文献   

18.
A series of novel fused tetracyclic benzo[4,5]imidazo[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and 1H‐benzo[d]imidazol‐2‐amine in glacial acetic acid. This protocol features mild reaction conditions, high yields and short reaction time.  相似文献   

19.
A series of new polyamides containing both sulfone and oxyethylene moieties in the polymer chain was prepared by the direct polycondensation of the diamine monomer 2,2‐bis[4‐[2‐(4‐aminophenoxy)ethoxy]phenyl]sulfone (BAEPS) and various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. Polymers were produced with inherent viscosities of 0.30–0.60 dl/g and identified by elemental analysis, and infrared and nuclear magnetic resonance spectra. Most of the polymers were readily dissolved in polar solvents such as NMP, dimethylsulfoxide, N,N‐dimethylacetamide, N,N‐dimethylformamide and m‐cresol at room temperature. Polymers containing rigid and symmetric p‐phenylene, naphthalene and p‐biphenylene moieties revealed a crystalline nature and showed no solubility in organic solvents. These polyamides had 10% weight loss temperatures ranging between 423 and 465 °C in nitrogen atmosphere and glass transition temperatures between 170 and 305 °C. The polymers with crystallinity nature exhibited melting endotherms (Tm) below 386 °C in differential scanning calorimetry trace. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

20.
4‐Hydrazino‐2‐methylpyrimidino[4′,5′:4,5]thiazolo[3,2‐a]benzimidazole ( 4 ) was obtained from hydrazinolysis of the 4‐chloro derivative 3 with hydrazine hydrate. The hydrazino derivative 4 was further cyclized to the corresponding pyrazole 5 , pyrazolone 6 and 5‐methyl‐1,2,4‐triazolo[1″,5″:3′,4′]pyrimidino[5′,6′:5,4]‐thiazolo[3,2‐a]benzimidazole ( 9 ) and 5‐methy‐1,2,4‐triazolo[4″,3″:3′,4′]pyrimidino[5′,6′:5,4]thiazolo‐[3,2‐a]benzimidazole ( 10 ), respectively. The triazolo derivative 10 was isomerized to the triazolo derivative 9 under a variety of reaction conditions.  相似文献   

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