Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Komplexe des zweiwertigen Molybdäns,Derivate des Oktahalodimolybdat(II)-Ions, 4. Mitt.: Darstellungen und Kristallstrukturen von zwei neutralen Komplexen mit 4-Methylpyridin

Mo₂Cl₄ Pic ₄·CHCl₃ (A) (Pic=4-methylpyridine) and Mo₂Br₄ Pic ₄ (B) crystallize in the monoclinic space group.A inC2/c (No. 15) witha=15.175 (4),b=10.847 (2),c=19.946 (6) and =104.52 (2)°;D _o=1.71 (2),D _c =1.72 gcm^–3 forZ=4.B inP2_l/n (No. 14) witha=9.270 (3),b=16.614 (5),c=9.305 (3) and =91.96 (5)°;D _o=2.03 (3),D _c =2.05 gcm^–3 forZ=2.Two halogens and 4-methylpyridines of the MoX ₂ Pic ₂ group are in the trans position. Mo–Mo bond lengths are 2.153 96) forA and 2.150 92) forB. Both molecules are situated on the inversion center resulting in the eclipsed configuration of the ligands around the molybdenum pair. The structure ofB has been refined to the conventionalR factors of 0.08 and 0.098. Disorder on the part of 4-methylpyridines and chloroform molecules stopped the refinement ofA at the endR value of 0.175.Mean Mo–X and Mo–N bonding distances are 2.40 (2), 2.25 (5) forA and 2.53 (3), 2.25 (1) forB.

     

Hydrothermal synthesis,characterization, and luminescence of two new arsenic–vanadium compounds with a γ-[As8V14O42(H2O)]4− anion

Two new compounds, [Zn(phen)₃]₂[γ-As₈V₁₄O₄₂(H₂O)]?·?4H₂O (1) and [Cd(phen)₃]₂[γ-As₈V₁₄O₄₂(H₂O)]?·?2H₂O (2) (phen?=?1,10′-phenanthroline), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, infrared spectrum, and thermogravimetric analysis. Compound 1 crystallizes in the triclinic space group P 1 with a?=?11.429(4)?Å, b?=?15.760(5)?Å, c?=?15.952(5)?Å, α?=?108.825(5)°, β?=?92.194(5)°, γ?=?104.155(5)°, V?=?2615.6(15)?ų, Z?=?1; 2 crystallizes in the triclinic space group P 1 with a?=?11.450(4)?Å, b?=?15.629(6)?Å, c?=?16.302(6)?Å, α?=?109.177(5)°, β?=?92.628(5)°, γ?=?104.251(4)°, V?=?2644.8(17)?ų, Z?=?1. Single-crystal structural analysis shows that both 1 and 2 consist of a new type of [γ-As₈V₁₄O₄₂(H₂O)]^4? cluster anion.     

Fading of a novel colorimetric receptor after recognizing H2PO4−

A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H₂PO₄^? ion was reported. Fancifully, the recognition process of receptor 1 to H₂PO₄^? was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H₂PO₄^? that H₂PO₄^? ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV–vis, fluorescence, ¹H NMR titrations and ESI-MS experiments.     

Reactions of GeMe2-bridged dicyclopentadienes with molybdenum carbonyl: formation of germylidyne trimolybdenum clusters

In thermal reactions of the doubly bridged dicyclopentadienes (C₅H₃R(SiMe₂))(C₅H₃R(GeMe₂)) (R=H (1), ^tBu (5)) with Mo(CO)₆, the bridging GeMe₂ is cleaved to give the corresponding degermylated products [(η⁵-C₅H₃R)₂(SiMe₂)]Mo₂(CO)₆ (3, rac-7), or both GeMe₂ and SiMe₂ are cleaved to afford the nonbridged products [(η⁵-C₅H₄R)Mo(CO)₃]₂ (2, 6). The reactions also produce germylidyne trimolybdenum clusters [(η⁵-C₅H₃R)₂(SiMe₂)](η⁵-C₅H₄R)[Mo(CO)₂]₃(μ₃-GeMe) (4, rac-/meso-7) containing the Mo₃(μ₃-GeMe) units. Similarly, reaction of the single GeMe₂-bridged dicyclopentadienes (C₅H₅)₂GeMe₂ (9) with Mo(CO)₆ also results in the degermylated 2, as well as the similar trimolybdenum cluster [(η⁵-C₅H₅)Mo(CO)₂]₃(μ₃-GeMe) (10). The molecular structures of 4 and trans-5 were determined by X-ray diffraction.     

Reactions of pyridine-2-ethyl/methyl cyclopentadienes with metal carbonyls

Abstract

Thermal treatment of pyridine-2-ethyl cyclopentadiene (1) with Fe(CO)₅ and Ru₃(CO)₁₂ gave novel intramolecular C–H activated dinuclear products (3 and 5). In the case of Fe(CO)₅, the reaction also afforded the normal bis(cyclopentadienyl) diiron complex (4). However, similar reaction of pyridine-2-methyl cyclopentadiene (2) with Fe(CO)₅ and Ru₃(CO)₁₂ only afforded the normal bis(cyclopentadienyl) dinuclear metal complexes (7 and 8). For Ru₃(CO)₁₂, the reaction also yielded a pendant η¹-pyridyl-coordinated product (9). In addition, the reactions of 1 and 2 with Re₂(CO)₁₀ formed the corresponding pyridylethyl/pyridylmethyl cyclopentadienyl rhenium tricarbonyl complexes 10 and 11, which further underwent pyridine to rhenium cyclization via photoirradiation to provide the rhenium dicarbonyl complexes 12 and 13. The molecular structures of 3, 5, 6, 7, 8, 9, and 12 were determined by X-ray diffraction.     

Synthesis and characterization of an anion triazole framework containing μ 3-Cl and μ 2-Cl bridges

Using 3,5-dimethyl-4-amino-1,2,4-triazole (L) and corresponding Ag(I), K(I) salts under ammonia solution and hydrothermal conditions, a triazole–silver(I)–potassium(I) complex {K[Ag₂L₂(μ ₃-Cl)(μ ₂-Cl)₂]} _n (1) has been isolated. In 1, μ ₃-Cl, μ ₂-Cl and L bridge Ag^I ions forming a rare 1-D [Ag₂L₂(μ ₃-Cl)(μ ₂-Cl)₂]^? anion while K⁺ cations are located between neighboring anion chains. Strong solid-state fluorescence spectrum of 1 was also investigated showing that the excited peak is located at 320 nm while the maximum emission peak is located at 440 nm.     

Hydroxylation of a vitamin D A-ring fragment

Summary When the benzoate of (S)-(Z)-2-(5-(tert-butyldimethylsiloxy)-2-methylencyclohexyliden)-ethanol (5) is treated with 2.5 equivalents of Hg(OOCCF₃)₂ in dryTHF, a smooth and selective allylic hydroxylation occurs. The C-1 functionalized vitamin D A-ring synthon6 is isolated in 65 to 70% yield in a single step.

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Hydroxylierung eines Vitamin D A-Ring-Fragments (Kurze Mitt.)

Zusammenfassung Umsetzung des Benzoats von (S)-(Z)-2-(5-(tert-Butyldimethylsiloxy)-2-methylencyclohexyliden)-ethanol (5) mit 2.5 Äquivalenten Hg(OOCCF₃)₂ in trockenemTHF führt zu einer selektiven allylischen Hydroxylierung. Damit ist das an C-1 funktionalisierte Vitamin D A-Ring-Fragment6 in einem einzigen Schritt in einer Ausbeute von 65 bis 70% zugänglich.

     

Molecular complexes of C60 with tetrasulfur tetranitride

Compounds C₆₀(S₄N₄)_2−x (C₆H₆) _x (1a-d) withx=0.67 (a), 1.0 (b), 1.1 (c), and 1.2 (d), in which isomorphous replacement of S₄N₄ with benzene takes place, were obtained by the reaction of fullerence C₆₀ with tetrasulfur tetranitride in benzene. Complexes C₆₀·S₄N₄ (2) and C₆₀(S₄N₄)₂ (3) containing no solvent were isolated from toluene. The compositions of the compounds were established by elemental and thermogravimetric analyses. The data of IR and X-ray photoelectron (XP) spectroscopies show that in the complexes studied the transfer of electron density occurs mainly from the nitrogen atoms of S₄N₄. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 37–40. January 1977.     

Untersuchungen der Hydroxylammonium-Fluorozirconate(IV)

Summary Hydroxylammonium fluorozirconates have been investigated. Two new microcristalline phases have been isolated from aqueous solutions: (NH₃OH)₂ZrF₆ (1) and (NH₃OH)₃ZrF₇ (2). The crystals were prepared by slow evaporation of the solution of NH₂OH, Zr, and HF. Different compositions of the crystals were achieved by varying the molar ratios of the components. They were characterized by thermal analysis, vibrational spectroscopy, and structure (single crystal x-ray methods). (NH₃OH)₂ZrF₆ (1) crystallizes triclinic, P (No.: 2),a=7.400(2),b=7.609(2),c=7.887(2) Å, =57.29(3)°, =62.16(3)°, =67.83(2)°. (NH₃OH)₃ZrF₇ (2) crystallizes triclinic, P (No.: 2),a=7.128(1),b=7.989(1),c=8.888(1) Å, =109.72(1)°, =91.01(1)°, =104.27(1)°.

     

Structures and magnetism of two manganese crowns assembled with 2,4-dihydroxyacetophenone oxime

Reactions of 2,4-dihydroxyacetophenone oxime with manganese salts yielded two manganese crowns, [Mn₃(μ ₃-O)(4-OH-Me-sao)₃(HCOO)(MeOH)₅]·MeOH (1) and [Mn₃(μ ₃-O)(4-OH-Me-sao)₃(CH₃COO)(MeOH)₅]·MeOH (2) (4-OH-Me-saoH₂=2,4-dihydroxyacetophenone oxime). Both compounds possess [Mn^III ₃(μ ₃-O)]⁷⁺ cores which contain 9-MC-3 metallacrown (MC) rings with the repeating pattern [–Mn–N–O–]. However, the difference in the structures of both compounds is coordinated carboxylates. In 1 and 2, the MC molecules are connected with each other through intermolecular hydrogen bonds, generating similar 3-D supramolecular networks. Magnetic properties reveal that in 1 and 2 the metal ions exhibit ferromagnetic exchange coupling.     

Sol–Gel Approach to Sr<Subscript>2</Subscript>CeO<Subscript>4</Subscript> Phosphor from Single Alkoxide Precursors

Syntheses and characterizations of sol–gel precursors of Sr₂CeO₄ were carried out. Each molecular precursor, [Sr₂Ce(OCH₂CH₂OCH₃)₈] (1), [Sr₂Ce(OⁱPr)₈] (2) and [Sr₂Ce₂(OⁱPr)₁₂(ⁱPrOH)₄] (3) was prepared from mixtures of Sr complexes and cerium(IV) alkoxides. The molecular structure of 3 showed that [CeO₆] octahedra are connected with distorted [SrO₆] octahedra by sharing edges with oxo bridges. X-ray powder diffraction patterns and spectrofluorometry were used to determine the evolution of structure from the precursor molecules to the luminescent oxides. The luminescent strontium cerium oxides were derived at relatively mild reaction conditions (700 °C for 1 h), and complete conversion was observed at 1000 °C for 1 h from these precursors. Comparing the spectra of the oxides derived from 2 and 3, the emission intensity of the oxide derived from 2 is much stronger.     

Reactions ofo-tosylaminobenzaldehyde withp-aminobenzenesulfonamides. Synthesis and structures of 13-(4-aminosulfonylphenyl)-6,12-epimino-5,11-ditosyl-5,6,11,12-tetrahydrodibenzo[b,f]-1,5-diazocine and itsN-substituted derivatives

The reactions ofo-tosylaminobenzaldehyde (1) withp-aminobenzenesulfonamides (2a-c) yielded 13-(p-RNHSO₂C₆H₄)-6,12-epimino-5,11-ditosyl-5,6,11,12-tetrahydrodibenzo[b f]-1,5-diazocines (3a-c) (R=H (a); 2-thiazolyl (b); or 2,6-dimethoxy-4-pyrimidinyl 2,6-dimethoxy-4-pyrimidinyl (c). The structure of compound3c was confirmed by X-ray diffurction study. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2035–2039, November, 1997.     

Modification,characterization and peroxidase-mimetic properties of calcined product of a cobalt compound

One-pot solvothermal treatment of Co(NO₃)₂·6H₂O, H₂L (5-(3-methyl-5-(pyridin-4-yl)-4H-1,2,4-triazol-4-yl) isophthalic acid), and 4,4′-bipyridine (4,4′-bipy) in H₂O/DMF (V/V = 1?:?1) yielded a cobalt-organic chain, [Co(L)(O)(H₂O)₂]_n·1.25nH₂O (1). Compound 1 as raw materials was calcined to obtain Co₃O₄, which could be confirmed by PXRD and SEM. Via the modification, Co₃O₄@SiO₂-NH₂ and Co₃O₄@SiO₂-NH₂-FA samples could be obtained. Compared to Co₃O₄@SiO₂-NH₂, Co₃O₄@SiO₂-NH₂-FA seems to have better peroxidase-mimetic properties. UV–vis results showed that optimal conditions of peroxidase-mimetic experiments were at 50°C in sodium acetate-acetic acid buffer (pH 3.6, 0.2 M), when the concentration of tetramethylbenzidine (TMB) was 0.2 mM. A concentration-dependent manner was shown between the concentration of glucose and absorbance in the measurement experiments for glucose.     

哒嗪酮类α1-肾上腺素受体拮抗剂的合成和生物活性研究

将苯(氧)乙胺和苯氧烷胺类α₁-肾上腺素受体拮抗剂中的苯(氧)乙胺、苯氧烷胺片段引入哒嗪酮类化合物中, 设计、合成了30个新的含哒嗪酮环的α₁-肾上腺素受体拮抗剂. 所有新化合物的结构均经¹H NMR, IR, HRMS确证. 生物活性测试表明28个目标物对α₁-肾上腺素受体有较好的拮抗作用(pA₂＞6.00), 化合物6o, 6p, 6q, 6v, 6x, 6y, 10c, 10d的pA₂值＞7.00.     

Calixarenes functionalised water-soluble iron oxide magnetite nanoparticles for enzyme immobilisation

ABSTRACT

In this study, we first used water-soluble iron oxide nanoparticles for Candida rugosa lipase immobilisation. Moreover, two new complexation phenomena of the prepared water-soluble Fe₃O₄ nanoparticles with an enzyme might address interesting results in terms of enzyme activity and stability in typical enzymatic reactions. The catalytic activity on pH and temperature dependence, and reusability of the immobilised lipases ( p-SCX4-NP-E and p-SCX8-NP-E) were also investigated with the hydrolysis reaction of p-nitrophenyl palmitate (p-NPP). The results show that the highest catalytic affinities for p-SCX4-NP-E and p-SCX8-NP-E were obtained at pH 5.0 and pH 7.0, respectively.     

Synthesis, crystal structure and spectroscopic properties of two new complexes containing azido or dicyanamido bridges

Two new complexes, [Cu(L₁){N(CN)₂}]·ClO₄ (1) (L₁ is 1,8-dimethyl-1,3,6,8,10,13-hexa-azacyclotetradecane) and [Co(L₂)(N₃)₂]·ClO₄ (2) (L₂ is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane) have been synthesized and characterized. The compounds crystallize in the monoclinic system P2₁ space group for 1 and P2₁/n for 2. Single crystal X-ray analysis reveals that the compound 1 assumes a one-dimensional structure via hydrogen-bonding interactions, in which each Cu(II) ion is coordinated by four nitrogen atoms from ligand L₁ and one nitrogen atom from [N(CN)₂]⁻ anion. For compound 2, each Co(III) ion is coordinated by four nitrogen atoms of ligand L₂ and two nitrogen atoms from N₃ ⁻ anion.     

Crystal structures and luminescence of two cadmium(II) polymers constructed from aromatic polycarboxylate and bis(1,2,4-triazol-1-yl)methane ligands

Two new coordination compounds, {[Cd₂(btrm)(ip)₂(H₂O)₂]?·?2H₂O} _n (1) and {[Cd₂(btrm)(hip)₂(H₂O)₄]?·?3H₂O} _n (2) (btrm?=?bis(1,2,4-triazol-1-yl)methane, H₂ip?=?isophthalic acid, H₂hip?=?5-hydroxy isophthalic acid), have been synthesized and structurally characterized. Compound 1 is a 3-D network with CdSO₄ topology. Compound 2 contains 1-D ladder structures, which are interconnected by classical hydrogen-bonding interactions (O–H?···?O) to lead to 3-D supramolecular architectures. Luminescence was performed on 1 and 2, both of which showed strong fluorescent emissions in the solid state at room temperature.     

Exploratory syntheses,structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse Pb^II coordination complexes, [Pb₃O(OH)(4-sphth)]₂(H₂O) (1), [Pb(3,5-Hdhb)]H₂O (2), and [Pb₃(4-nphth)₂(OH)₂] (3) (4-H₃sphth, 4-sulfophthalic acid; 3,5-H₂dhb, 3,5-dihydroxybenzoic acid; 4-H₂nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb₄O₄] cubanes, based on which ladder-shaped structure is built via 4-H₃sphth bridge. This is the first Pb₄O₄-containing polymer. The Pb₂O₂ units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb₃O units, which are linked through Pb corners to form a hexagonal unit. Each PbO₆ polyhedron is connected to three polyhedra (Pb₃O) via sharing an edge (two μ ₃-oxygen atoms) and two faces (three μ ₃-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.