Preparation of nano-sized polybenzimidazole and carbon particles via poly(amino-amide) particles

Poly(amino-amide; PAA) particles consisting of p-phthalyl chloride and 3,3′-diaminobenzidine and 4,4′-diphenyldicarbony chloride and 3,3′-diaminobenzidine were prepared. The particles were then transformed by treatment with heat into poly(p-phenylenebenzimidazole; PPC–PAA) and poly(4,4′-diphenylenebenzimidazole; DPC–PAA) particles, respectively. The number ratio of ring-closing of the obtained product was found to be dependent on the processing temperature. However, the morphology and diameter of the products were not found to be temperature dependent. PPC–PAA particles were amorphous and DPC–PAA particles had a high degree of crystallinity. Further, upon heating up to 1,000 °C, poly(p-phenylenebenzimidazole) and poly(4,4′-diphenylenebenzimidazole) particles were transformed into carbon particles and carbon bulk, respectively. The poly(amino-amide), polybenzimidazole and carbon particles obtained were nano-sized spherical particles with narrow size distributions.     

Design of postmetallocene catalytic systems of aryliminetype for olefins polymerization: XIII. Synthesis of tetradentate bis(2-hydroxy-1-naphthaldimine) ligands and their complexes with titanium(IV) dichloride

Reactions of 2-hydroxy-1-naphthaldehyde with 1,4-diaminobutane, 1,6-diaminohexane, 4,4′-methylenedianiline and its alkyl- and cycloalkyl-sybstituted derivatives, with 4,4′-sulfonyldianiline, 2,2′- and 4,4′-oxydianiline, 4,4′-(1,4-phenylenebisoxy)dianiline, 4,4′-[propane-2,2-diylbis(1,4-phenylenebisoxy)]dianiline, and p-terphenyl-4,4″-diamine afforded a series of the corresponding diimines that at treating with TiCl₂(OPr-i)₂ formed mono- and binuclear complexes of titanium(IV) dichloride with tetradentate ligands LTiCl₂ and L₂(TiCl₂)₂.     

Synthesis and studies of homopolyamides based on 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine

Abstract  

Ten homopolyamides have been synthesized by polycondensation of the monomer 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine and different diamines such as 4,4′-biphenyldiamine, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfonamide, 2,4-diaminotoluene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, and ethylenediamine. All polyamides were characterized by solubility, density, viscosity measurements, IR, NMR spectroscopy, and thermogravimetric analysis. The products were found to possess high thermal stability.     

Structures of oxidation products of 4,6-di-tert-butylpyrogallol

Oxidation of 4,6-di-tert-butylpyrogallol gave two dimeric products instead of the expected 4,6-di-tert-butyl-3-hydroxy-1,2-benzoquinone (2). It was established by X-ray diffraction analysis that the first product has the structure of tetra-tert-butyl-6, 10a-dihydroxy-1,2-dioxo-3,4a,7,9-1,2,4a, 10a-tetrahydrodibenzo-1,4-dioxine. From this it follows that compound 2 undergoes regio- and stereospecific dimerization according to the [2π+4π]-cycloaddition mechanism,viz, the hetero Diels—Alder reaction. The double intensities of the signals in the¹H NMR spectrum are indicative of a symmetrical structure of the second product, 2,6,4′, 6′-tetra-tert-butyl-4,4′-dihyroxy-3,5,3′,5′-tetraoxo-4,4′-bi(cyclohexene), which is a racemate of enantiomers formed upon recombination (r+r orl+l) of the intermediate of oxidation of pyrogallol, namely, of ther,l-stereogenic 3,5-di-tert-butyl-1-hydroxy-2,6-dioxocyclohex-3-enyl radical. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 139–146, January, 1999.     

Cyclopalladated complexes of 2-phenylbenzothiazole with 4,4′-bipyridyl

Complexes [Pd(bt)(4,4′-bpy)OOCCH₃], [Pd(bt)NO₃]₂(m-4,4′-bpy), [Pd(bt)(m-4,4′-bpy)]₄(NO₃)₄ (bt⁻ is deprotonated form of 2-phenylbenzothiazole, bpy is 4,4′-bipyridyl) are prepared and characterized by ¹H NMR, electron absorption and emission spectroscopy, as well as by voltammetry. The upfield shift of the signal of proton in the ortho-position to the donor carbon atom of the cyclopalladated ligand in the complexes [(Δδ = −(1.1–1.5) ppm] is assigned to the anisotropic effect of the ring current of the pyridine rings of the 4,4′-bipyridyl moiety, which are orthogonal to the coordination plane. Characteristic longwave absorption bands λ = (387±4) nm and the low-temperature phosphorescence bands λ = (512±3) nm in the complexes are assigned to the chromophore {Pd(bt)} metal complex fragment. The reduction waves in the complexes [E _1/2 = −(1.54±0.04) and E _p = −(1.83±0.03) V] are assigned to the ligand-centered processes of the successive electron transfer to the π* orbitals localized predominantly on the coordinated pyridine components of the 4,4′-bipyridyl moiety.     

Syntheses, structures and properties of two new neodymium complexes with N-P-acetamidobenzenesulfonyl-glycine acid

Two new neodymium complexes, [Nd₂(abglyH)₆(2,2′-bipy)₂(H₂O)₂] · 4H₂O 1 and {[Nd(abglyH)₃(H₂O)₂] · (4,4′-bipy) · 7H₂O}_n 2 (abglyH₂ = N-P-acetamidobenzenesulfonyl-glycine acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), have been synthesized and their structures have been measured by X-ray crystallography. In 1, nine-coordinated Nd(III) ions are bridged by two syn–syn bidentate and two tridentate bridging carboxylate groups from four different abglyH⁻ anions to form dinuclear motifs, which are further connected into a 3-D supramolecular framework via hydrogen bonds between the binuclear motifs and the uncoordinated water molecules. In 2, eight-coordinated Nd(III) ions are linked by six carboxylate groups adopting a syn–syn bidentate bridging fashion to form a 1-D inorganic–organic alternating linear chain. These polymeric chains generate microchannels extending along the a direction, and these cavities are occupied by discrete tetradecameric water clusters, which interact with their surroundings and finally furnish the 3-D supramolecular network via hydrogen bonds. At the same time, π–π stacking interactions between benzene rings from abglyH⁻ anions also play an important role in stabilizing the network.     

Preparation et caracterisation de complexes [cis-4,4′-dinitrodibenzo-18-couronne-6, LnCl3, 3CH3CN]

Some new complexes between thecis-4,4′-dinitrodibenzo-18-crown-6 and rare earth chlorides LnCl₃ (Ln=Nd, Gd, Yb) were synthesized in acetonitrile. Ligandcis-4,4′-dinitrodibenzo-18-crown-6 and its complexes were identified by infrared spectroscopy, X-ray diffraction and thermal analysis (TG and DTA). Acis-trans isomerisation of the complexed ligand is observed about 148°C when heating the rare earth complex.

     

New bioactive constituents from eleutherine americana

Three new constituents were isolated from Eleutherine americana Merr. et K. Heyne (hong-cong) by means of silica gel, octadecyl silane (ODS) column chromatography and high-performance liquid chromatography (HPLC). They were identified as (1) 9,9′-dihydroxy-8,8′-dimethoxy-1′-dimethyl-1H, 1H′-[4,4′]bis[naphtha[2,3-c] funanyl]-3,3′-dione; (2) 6,8-dihydroxy-3,4-dimethoxy-1-methyl-anthraquin-one-2-carboxylic acid methyl ester; and (3) 2-acetyl-3,6,8-trihydroxy-1-methyl anthraquinone by the physico-chemical properties and spectral data, respectively. All three compounds showed weak activities against the growth of Pyricularia oryzea. The minimum morphological deformation concentration (MMDC) was 145.8, 50.2, and 124.8 μg/mL. Additionally, (2) also inhibited the proliferation of human erythroleukemia cancer cell line K562 with IC₅₀ value of 49.1 μg/mL. __________ Translated from Chemical Journal of Chinese Universities, 2005, 26(11) (in Chinese)     

Synthesis of Aryl- and Pyridinyl-substituted 2-Amino-6-thioxopyridine-3-carbonitrile Derivatives by Tandem Michael Addition and Cyclization Reactions

Summary. The tandem Michael addition and cyclization of 2-, 3-, and (4-pyridinylcarbonyl) thioacetanilides with arylidenemalononitriles yielded polysubstituted pyridines and bipyridines. Tetrahydro-6-thioxopyridine-3-carbonitrile was dehydrogenated to its dihydro derivative by means of HgO or DBU. The reaction of enamines of 3-, and (4-pyridinylcarbonyl)thioacetanilides with malononitrile furnished 3,4′- and 4,4′-bipyridines.     

Pseudo[3]rotaxane Type Compelxation between α- and β-Cyc1odextrins and N,N′-Dsiheptyl-4,4′-bipyridinium

Pseudo[3]rotaxane type complexation of α- and β-cyclodextrins (α- and β-CDs, respectively) with N,N′-Diheptyl-4,4′-bipyridinium (diheptyl viologen; HV²⁺) was investigated. A spectral displacement method using p-nitrophenol as a dye revealed that α-CD and HV²⁺ formed a 2:1 host-guest complex with stability constants being 3280 and 976 M⁻¹ as the first and second steps of complexation, respectively. ¹H-NMR spectra strongly indicated that α-CD accommodated the heptyl groups of HV²⁺. Although previous studies based on circular dichroism spectroscopy suggested the primary hydroxy side of α-CD faced to the positively charged bipyridinium moiety od HV²⁺, 2D-NMR studies clearly demonstrated that the secondary hydroxy side of α-CD faced to the bipyridinium moiety. β-CD also formed a 2:1 complex with HV²⁺ with a similar fashion.     

peri-Naphthylenediamines

4,5,4′,5′-Tetrakis(dimethylamino)-1,1′-binaphthalene, unknown previously, was obtained in ∼20% yield by the oxidation of 1,8-bis(dimethylamino)naphthalene with Tl(OAc)₃ or Pb(OAc)₄ at low temperatures. Treatment of the reaction product with excess Li and then with O₂ gave, depending on the reaction temperature, perylene or 4,4′-bis(dimethylamino)-1,1′-binaphthalene in good yields, instead of expected 3,4,9,10-tetrakis(dimethyl-amino)perylene. For Part 23, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 93–98, January, 1998.     

1-( p -Fluorophenyl)-2-(2′-pyridyl)ethanol and 1-( p -fluorophenyl)-2-(2′-pyridyl)ethene obtained from the condensation reaction of 2-picoline and p -fluorophenylaldehyde under catalyst-and solvent-free conditions

The novel intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol or 2-[2′-(1-hydroxy-1-(p-fluorophenyl)ethyl]pyridine and the corresponding novel dehydration compound 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene or 2-[p-fluorophenylvinyl]pyridine were obtained from the condensation reaction of p-fluorophenylaldehyde and 2-picoline under catalyst-and solvent-free conditions. The intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol was obtained at 42 h reaction time and temperature of 120°C, respectively. ¹H-NMR, IR spectroscopic data of the 1-(p-fluorophenyl)-2-(2-pyridyl)ethanol clearly showed the presence of the-CH₂-CHOH-group. The compound was obtained as a white powder with m.p. 121–122°C and a yield of 8%. For 1-(p-fluorophenyl)-2-(2-pyridyl)ethene, the reaction conditions were similar, but the reaction temperature was increased to yield the double bond in the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene. At the reaction temperature of 140°C, the compound was a slightly brown powder with a m.p. of 78°C and yield of 18%. ¹H-NMR, IR spectroscopic data for the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene showed the presence of a double bond in trans configuration (-CH=CH-), characteristic of a styrylpyridine.     

New hexaarylbenzene-containing di- and tetrafluoroarenes

New hexaarylbenzene-containing di- and tetrafluoroarenes were prepared by the Diels—Alder reactions of 1,4-bis(1-oxo-2,4,5-triphenylcyclopentadien-3-yl)benzene with 4-fluoro-4′-(phenylethynyl)- and 4-fluoro-4′-(4-fluorophenylethynyl)benzophenone, respectively. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1881–1883, August, 2005.     

Synthesis, characterization and catalytic epoxidation of cyclohexene using dimeric cis-dioxomolybdenum(VI) bis-bidentate Schiff base complexes supported on single wall carbon nanotubes

Three dimeric cis-dioxomolybdenum(VI) complexes of bis-bidentate Schiff base derivatives containing aromatic nitrogen–nitrogen linkers (4,4′-diaminodiphenylmethane; 4,4′-diaminodiphenylether; 4,4′-diaminodiphenylsulfone) with 2-hydroxy-1-naphthaldehyde have been synthesised and characterized by physico-chemical and spectroscopic methods. The catalytic activities of the complexes with respect to alkene epoxidation using tert-butylhydroperoxide (TBHP) as oxidant have been studied. The addition of single wall nanotubes can enhance the catalytic activities of the Mo complexes and the selectivity of epoxide formation.     

Laser Raman spectroscopic study of photoreaction dynamics in p -chloro cinnamic acid crystal

Raman phonon spectroscopy has been used to study photodimerization reaction inp-chloro cinnamic acid (pCCA) crystal. The β-form of the crystal yields the 4,4′-dichloro-β-truxinic acid dimer. Six distinct low frequency phonon bands are observed in thepCCA monomer crystal. On reaction progress, these bands show a monotonic shift to lower frequencies and broaden out. Finally, in the dimer crystal the phonon spectrum shows two weak broad bands. These results suggest that the reaction is homogeneous in the initial stages and, as the product concentration increases, the lattice becomes highly disordered. The reactant and the product were characterised by infrared and Raman spectroscopy. The disappearance of aliphatic C=C bond stretching vibration and appearance of cyclobutane ring deformation and cyclobutane ring-breathing vibrations on reaction confirm photodimerization by cyclobutane ring formation. The large Stoke's shift between the absorption and emission band suggest strong exciton-phonon coupling in the monomer lattice. This reaction seems to be phonon-mediated.     

Syntheses and characterization of three hybrid materials based on polymeric copper complexes and saturated Keggin polyoxoanions

Three novel heteropolytungstates, [Cu(phen)₂]₄[α-SiW₁₂O₄₀] (1), [Cu₄(4,4′-bpy)₃(2,2′-bpy)₄][α-SiW₁₂O₄₀] · H₂O (2) and [Cu(4,4′-bpy)(4,4′-Hbpy)_0.5]₂[PW₁₂O₄₀] (3) (phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR, TG analyses and single-crystal X-ray diffraction. Compound (1) exhibits interesting chiral layer constructed from interperpendicular helical chains running along a crystallographic 2₁ axis in the c and a directions. Furthermore, the chiral layers are connected by the [α-SiW₁₂O₄₀]⁴⁻ anions via hydrogen bonding interactions to form a 3D superamolecular structure. The [Cu₄(4,4′-bpy)₃(2,2′-bpy)₄]⁴⁺ coordinated complexes in compound (2) are packed together via the aromatic π–π stacking interactions and exhibit an interesting 3D sandglasslike “host” network with 1D channels, in which [α-SiW₁₂O₄₀]⁴⁻ anions “guests” reside. Compound (3) has a unique 2D superamolecular network, which is composed of cationic Cu^I coordination polymer chains and discrete [PW₁₂O₄₀]³⁻ polyoxoanions as linkers. It is noteworthy that the monprotonated 4,4′-bpy ligands of (3) act as arms and connect the adjacent 2D network, generating a 3D interpenetrating superamolecular structure.     

The behavior of <Emphasis Type="Italic">p</Emphasis>-bis{3-[N-(3-chloro-buten-2-yl)pyrrolidinio(piperidinio or morpholinio)]propyn-1-yl}benzene dichlorides in an aqueous base medium

In aqueous base medium p-bis{3-[N-(3-chlorobuten-2-yl)pyrrolidinio (piperidinio or morpholinio)]-propyn-1-yl}benzene dichlorides undergo a two-way dehydrochlorination-cyclization reaction to form benzo[5,6-a:5′,6′-c]bis(2,2-tetramethylene- or -2,2-pentamethylene-4-methylisoindolinium) and benzo-[5,6-a:5′,6′-c]bisspiro(4-methylisoindoline-2,4′-morpholinium) dichlorides. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 546–549, April, 2009.     

Reactions of 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepin-5-one with phenanthrenequinone and dibenzoyl

Reactions of 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepin-5-one with 9,10-phenanthrenequinone and dibenzoyl gave hydrolytically unstable spirophosphoranes with five- and seven-membered rings, 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydrospiro[[1,3,2]benzodioxaphosphepine-2,2′-phenanthro[9,10-d][1,3,2]dioxaphosphol]-5-one and 2,4′,5′-triphenyl-4,4-bis(trifluoromethyl)-4,5-dihydrospiro[[1,3,2]benzodioxaphosphepine-2,2′-[1,3,2]dioxaphosphol]-5-one. The structure of the first of these was proved by X-ray analysis.     

Thermal decomposition of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with rare-earth elements in air atmosphere

The present work provides data concerning thermal decomposition of 2,2′-dipyridyl(2-dipy) and 4,4′-dipyridyl(4-dipy) with rare-earth elements (Ln) based on literature and our own sustained studies which comprised about 100 complexes.

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Zusammenfassung Ausgehend von Literaturangaben und unseren eigenen Untersuchungen von mehr als 100 Komplexen liefert vorliegende Arbeit Angaben zur thermischen Zersetzung von 2,2′-Dipyridyl(2-dipy) und 4,4′-Dipyridyl(4-dipy) mit Seltenerdenelementen (Ln).

     

Construction of novel coordination polymers with simple ligands

Three different types of metal-organic polymers have been prepared by a solution diffusion process carried out at room temperature. Crystals of the copper coordination polymers [CuX(4,4′-bipy)] _n (X = Cl, Br, I) have been obtained by the reaction of 4,4′-bipyridine ligands with Cu₂X₂ fragments to yield a three-dimensional network consisting of four interlocking planar lattices. Single crystals of [Cu₂(1,2,4,5-BTC)(DMF)₂] _n (1,2,4,5-BTC = 1,2,4,5-benzene tetracarboxylate) have been grown by slow diffusion from solutions of a mixture of CuBr₂, 2,2′-dithiosalicylic acid, and sodium azide plus a mixture of 1,2,4,5-H₄BTC and 4-cyanopyridine. The complex [Co(1,3,5-BTC)(4,4′-bipy)] _n (1,3,5-BTC = 1,3,5-benzene tricarboxylate) has a 3D open framework structure involving terminal cobalt atoms plus bridging 1,3,5-BTC and 4,4′-bipyridine ligands.