共查询到20条相似文献,搜索用时 46 毫秒
1.
Keiichi Satoh Toshio Suzuki Kiyoshi Sawada 《Monatshefte für Chemie / Chemical Monthly》2001,132(10):1145-1155
Summary. The molecular structures of bis-(pyridine base) complexes of cadmium(II) chloride and bromide, where the pyridine base is pyridine ( py), 3-methylpyridine (3-Me-py), 4-methylpyridine (4-Me-py), and 4-ethylpyridine (4-Et-py), were investigated by means of single-crystal X-ray diffraction and Raman spectroscopy. The crystal structures of CdCl2 py
2 (1), CdCl2(3-Me-py)2 (2), and CdCl2(4-Me-py)2 (3) were determined. All crystals are monoclinic; 1: a = 17.784(2), b = 8.666(1), c = 3.8252(7) ?, β = 91.54(1)°, space group: P21/n; 2: a = 11.89(1), b = 14.41(1), c = 3.874(6) ?, β = 92.3(1)°, space group: P21/a; 3: a = 21.091(2), b = 3.8884(5), c = 18.2317(3) ?, β = 113.64(1)°, space group: C2/c. The structures were refined to R/R
w
values (%) of 3.2/5.5, 3.0/5.0, and 3.4/5.1 for 1–3. All cadmium atoms are octahedrally coordinated with the chloride ions forming infinite di-μ-chloro polymeric linear chains
and the nitrogen atoms of the pyridine base in trans configuration. The Cd chains are oriented along the c-axis in 1 and 2 and along the b-axis in 3. The crystal structures indicate the absence of a peculiar interaction between the polymeric chains. The Raman spectra of eight complexes were measured in the range of 550–50 cm−1, and the Raman peaks originating from cadmium-halogen vibrations were assigned. The Raman spectra of 1 and 2 are quite alike in the lattice mode vibration region. The resemblance of the cadmium-halogen vibration peaks indicates the
same halogenide ion bridged octahedral structure for all complexes.
Received March 27, 2001. Accepted (revised) June 19, 2001 相似文献
2.
Zeliha Hayvali Hakan Dal Pinar Köksal Duygu Şahin Tuncer Hökelek 《Structural chemistry》2010,21(4):837-845
A series of benzyloxybenzaldehyde derivatives (1–3) were prepared by the reactions of 4-nitrobenzyl bromide with 4-hydroxy-3-methoxybenzaldehyde (vanillin), 2-hydroxy-3-methoxybenzaldehyde
(o-vanillin) and 2-hydroxy-4-methoxybenzaldehyde. When the reaction time is quite long, benzofuran derivatives (4 and 5) were obtained by the reactions of ortho-hydroxyaldehydes with the 4-nitrobenzyl bromide. Condensation reactions among the three benzyloxybenzaldehyde derivatives
(1–3) with 2-aminomethylfuran (furfurylamine) yielded the new imine compounds (6–8). The structures of these aldehydes (1–3), benzofuran derivatives (4 and 5) and imine compounds (6–8) were confirmed on the basis of elemental analyses, IR, 1H NMR and 13C NMR and mass spectroscopy. The solid-state structures of compounds 4–6 were determined by single-crystal X-ray crystallography. 相似文献
3.
Summary. A new simple, rapid, sensitive, and selective method is proposed for the microdetermination of mercury. Mercury(II) forms
insoluble complexes with 2,3-dichloro-6-(2-hydroxy-3,5-dinitrophenylazo)-quinoxaline (1), 2,3-dichloro-6-(5-amino-3-carboxy-2-hydroxy-phenylazo)-quinoxaline (2), 2,3-dichloro-6-(2,7-dihydroxynaphth-1-ylazo)-quinoxaline (3), and 2,3-dichloro-6-(3-carboxy-2-hydroxy-naphth-1-ylazo)-quinoxaline (4) in aqueous acidic medium; the complexes can be made soluble by the action of an anionic surfactant. The solution of the
pink coloured compounds is stable for at least 24 h. Beer’s law is obeyed over the concentration range from 0.1 to 2.8 μg · cm−3 of mercury. For a more accurate analysis, Ringbom optimum concentration ranges were found to be 0.25–2.5 μg · cm−3. The molar absorpitivity, Sandell sensitivity, and relative standard deviations were also calculated. A slight interference from Pd2+ and Cd2+ is exhibited by the first three ligands, whereas the last one is only negligibly affected by these metal ions. Strong interference
from Ag(I) is evident for all ligands, whereas alkali, alkaline earth, and other transition metals tested posed negligible
interference. 15 μg · cm−3 of Cd2+ and Pd2+ or 10 μg · cm−3 of Ag+ can be tolerated if 1.0 mg of potassium bromide and 2.0 mg of citrate as masking agents are added for the determination of
1.5 μg · cm−3 of mercury(II). The method was applied to the determination of methyl- and ethylmercury chloride and the analysis of environmental
water samples.
Received August 7, 2000. Accepted (revised) October 18, 2000 相似文献
4.
Gerald Schwarzenbacher Marion S. Gangl Marian Goriup Martin Winter Matthias Grunert Franz Renz Wolfgang Linert Robert Saf 《Monatshefte für Chemie / Chemical Monthly》2001,132(4):519-529
Summary. 11-(4H-1,2,4-Triazol-4-yl)-undecylmethacrylate (1), a new ligand for Fe(II) spin-crossover (SCO) complexes containing a polymerizable group, was synthesized and characterized.
The complex [Fe·1
3](BF4)2 (2) was obtained by reaction of 1 with Fe(BF4)2·6H2O (molar ratio 1/Fe(II) = 3/1) in THF. Complex 2 showed a gradual spin-crossover between 80 and 230 K. The methacrylate units in the ligands of complex 2 could be oligomerized radically in solution (initiator: azoisobutyronitrile) without loss of the spin-crossover behaviour.
Received May 30, 2000. Accepted December 10, 2000 相似文献
5.
Su-Fan Wang Ji-Kang Feng Chia-Chung Sun Peng Liu Zhen Gao Fan-Ao Kong 《Theoretical chemistry accounts》2001,106(3):163-170
The possible geometrical structures and relative stability of (SiS2)
n
(n=1–6) silicon–sulfur clusters are explored by means of density functional theory quantum chemical calculations. The effects
of polarization functions and electron correlation are included in these calculations. The electronic structures and vibrational
spectra of the most stable geometrical structures of (SiS2)
n
are analyzed by the same method. As a result, the regularity of the (SiS2)
n
cluster growth is obtained, and the calculation may used for predicting the formation mechanism of the (SiS2)
n
cluster.
Received: 17 November 1999 / Accepted: 3 November 2000 / Published online: 3 May 2001 相似文献
6.
Seon-Mi Seo Hak-Ju Lee Oh-Kyu Lee Hyun-Jin Jo Ha-Young Kang Don-Ha Choi Ki-Hyon Paik M. Khan 《Chemistry of Natural Compounds》2008,44(4):419-423
A new furofuran lignan (1) along with four knownones (2-5) were isolated from the bark of Magnolia kobus. Their structures were elucidated as (+)-2α-(3’,4’-dimethoxyphenyl)-6α-(3″-hydroxy-4″,5″-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane
(1), (+)-sesamin (2), (+)-yangambin (3), (+)-kobusin (4), and (+)-eudesmin (5) on the basis of their comprehensive spectroscopic analysis, including 2D NMR, and by comparison of their spectral data with
those of related compounds.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 338–341, July–August, 2008. 相似文献
7.
Jian Zhang Zhi-Qi Yin Peng Cao You-Bin Li Jin-Ao Duan 《Chemistry of Natural Compounds》2008,44(6):701-703
A new flavonol derivative 3, 8-dihydroxy-10-methoxy-5-H-isochromeno[4, 3-b]chromen-7-one (1) together with four known compounds, glutinone (2), luteolin (3), acacetin 7-O-α-L-rhamnopyranosyl- (1→6)-β-D-glucopyranoside (4), and rutin (5) were isolated from the dried roots of Fagopyrum dibotrys. Their structures were determined by UV, IR, MS, 1H, and 13C NMR spectroscopic analysis, including 2D NMR.
Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 567–568, November–December, 2008. 相似文献
8.
Four silver(I) complexes, namely [Ag2(bpe)2](bdc)·8H2O (1), [Ag2(bpe)2(da)]·4H2O (2), [Ag4(bpe)3(bptc)]·9H2O (3), and Ag(bpe)2(bpdc)2 (4), have been successfully synthesized by the reactions between AgNO3, 1,2-bis(4-pyridyl)ethane (bpe) and different carboxylic acids, including 1,3-benzenedicarboxylic acid (H2bdc), diphenic acid (H2da), 3,3′,4,4′-biphenyltetracarboxylic acid (H4bptc), and 2,2′-bipyridine-3,3′-dicarboxylic acid (H2bpdc). All four compounds were characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. In (1), the Ag(I) atoms, in linear geometry, are joined into 1-D infinite cationic bpe-silver chains, and discrete bdc2− anions compensate the charge of the crystal structure. In (2), the Ag(I) atoms, adopting tetrahedral and trigonal geometries, are linked by bpe and da2− ligands into neutral double chains. In (3), the Ag(I) atoms, in T-shaped and linear environments, are coordinated by bpe and multidentate bptc4− ligands to construct a 2-D network. And in (4), the Ag(I) atoms, with trigonal and T-shaped coordination geometries, are coordinated by bpe and bpdc2− ligands to build up a 3-D framework. The different anions play different and important roles in directing the final crystal
structures. 相似文献
9.
Nashwa M. H. Rizk 《Mikrochimica acta》2002,138(1-2):53-58
The construction and electrochemical response characteristics of poly(vinyl) chloride matrix membrane sensors for menadione
(vitamin K3) are described. Membranes incorporating the ion association complexes of menadione anion with bathophenanthroline nickel(II)
and iron(II) as electroactive materials show linear response for menadione over the range 10−1–10−5 M with anionic slopes of 58.2–51.4 mV per concentration decade. Both sensors exhibit fast response time (20–30 s), low detection
limit (2 × 10−5 M), good stability (4–6 weeks) and selectivity coefficient (10−1–10−3). Direct potentiometric determination of menadione under static and hydrodynamic mode of operations shows average accuracies
of 98.8 and 98.5% with relative standard deviations of 0.6% and 1.3%, respectively. Application of the method for the determination
of menadione in human plasma gives favourable results compared with those obtained by the standard spectrophotometric method.
Received February 26, 2001. Revision October 1, 2001. 相似文献
10.
Summary. The two new compounds Mn(dien)2[MoS4] (1) and Mn(dien)2[Mo2O2S6] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The
structures consist of new [Mn(dien)2]2+ cations and isolated tetrahedral [MoS4]2− (1) or [Mo2O2S6]2− (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P21/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry
(TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)).
Received November 5, 2001. Accepted December 27, 2001 相似文献
11.
A new dicarboxylic acid monomer containing the N-methylcarbazole and imide structures, 3,6-bis(trimellitimido)-N-methylcarbazole (I), was prepared from the condensation of 3,6-diamino-N-methylcarbazole (c) and trimellitic anhydride. The diamine c was synthesized in three steps starting from the methylation of carbazole, followed by nitration and catalytic hydrazine
reduction. A series of N-methylcarbazole-containing poly(amide–imide)s were synthesized by direct polycondensation from the diimide–diacid I with various aromatic diamines. These poly(amide–imide)s had inherent viscosities of 0.66–1.47 dl/g and were readily soluble
in a variety of organic solvents, including N-methyl-2-pyrrolidone and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films of these polymers could be cast from DMAc solutions, and
these films exhibited excellent mechanical strength. The glass-transition temperatures of these poly(amide–imide)s were in
the range 317–362 °C. All the poly (amide–imide) did not degrade noticeably below 480 °C in nitrogen, and the 10% weight loss
temperatures and char yields at 800 °C were above 520 °C and 60% in nitrogen, respectively, indicating high thermal stability.
Received: 8 February 2000/Accepted: 23 March 2000 相似文献
12.
A. N. Chekhlov 《Russian Journal of Inorganic Chemistry》2008,53(9):1465-1469
Three new crystalline complexes are synthesized: [K(18-crown-6)]+ · An, where An = [FeCl4]?(I), [FeBr2Cl2]? (II), and [FeBr4]? (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd $ \bar 3 Three new crystalline complexes are synthesized: [K(18-crown-6)]+ · An, where An = [FeCl4]−(I), [FeBr2Cl2]− (II), and [FeBr4]− (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd
(Z = 16): a = 20.770(2) ? for I, 20.844(3) ? for II, and 20.878(4) ? for III. Structures I–III are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.047 (I), 0.059 (II), and 0.098 (III) for all 680 (I), 684 (II), and 686 (III) independent reflections. In two tetrahedral anions [Fe(1)X4]− and [Fe(2)X4]− in structures I–III, all halogen atoms (X = Cl and Br) are randomly disordered over three close positions relative to the crystallographic axes
3. Structures I–III contain the [K(18-crown-6)]+ host-quest complex cation. The K+ cation (CN = 8) resides in the cavity of the 18-crown-6 ligand and coordinated by its six O atoms and two disordered halogen
X atoms. The coordination polyhedron of the K+ cation in complexes I–III is a distorted hexagonal bipyramid.
Original Russian Text ? A.N. Chekhlov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 9, pp. 1566–1570. 相似文献
13.
The spectroscopic properties of M–SiO and M–(SiO)2 (1–1 and 1–2 complexes with M = Cu, Ag, or Au) have been theoretically studied. It has been shown that both M–SiO and M–(SiO)2 compounds in their ground state are bent with a metal–Si bonded structure. The calculated M(ns) spin density agrees well with the electron spin resonance experimental data. From a topological analysis, it has been shown
that a rather large charge transfer occurs from the metal towards the SiO moiety, and that the M–Si bond energy correlates with the electron density located at the M–Si bond path (bond critical point).
Received: 6 July 2000 / Accepted: 11 October 2000 / Published online: 19 January 2001 相似文献
14.
P. P. Kushch S. V. Konovalikhin G. V. Shilov L. O. Atovmyan T. A. Khannanova R. N. Lyubovskaya 《Russian Chemical Bulletin》2000,49(2):372-374
The structure and conducting properties of a new radical cation salt of dibenzotetrathiafulvalene (DBTTF),viz., (DBTTF)11(TeCl6)4 (1), were studied. According to the X-ray diffraction data, the crystal of1 contains six crystallographically independent DBTTF radical cations alternating with stacks of the (TeCl6)2− anions. At room temperature, the conductivity of the crystals is 15 S cm−1 and it changes exponentially as the temperature decreases. It was found that an increase in the size of the anion in compounds
of type1 results in the appearance of interactions between the stacks and in an enhancement of the two-dimensional character of the
conductivity.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 370–372, February, 2000. 相似文献
15.
The reaction of N-benzoylphosphoramidic dichloride with amines afforded some new N-benzoylphos-phoric triamides with formula C6H5C(O)NHP(O)(X)2, X=NH–CH(CH3)2 (1), NH–CH2–CH(CH3)2 (2), NH–CH2–CH(OCH3)2 (3), N(CH3)[CH2CH(OCH3)2] (4) and N(CH3)(C6H11) (5) that were characterized by 1H,13C,31P NMR, IR spectroscopy and elemental analysis. The structures have been determined for compounds 4 and 5 by X-ray crystallography. These compounds contain one amidic hydrogen atom and form centrosymmetric dimmers via intermolecular
–P–O⋯H–N–hydrogen bonds besides weak C–H⋯O hydrogen bonds that lead to three-dimensional polymeric clusters in the crystalline
lattice. 相似文献
16.
V. N. Emel’yanenko S. P. Verevkin E. N. Burakova G. N. Roganov M. K. Georgieva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(8):1271-1279
The enthalpies of formation of δ-hexanolactone and δ-nonanolactone were determined by combustion calorimetry. Conformational
analysis and quantum-chemical calculations of equilibrium structures, fundamental vibrations, moments of inertia, and total
energies were performed for δ-pentanolactone (I), δ-hexanolactone (II), and δ-nonanolactone (III) by the B3LYP/6-311G(d,p), B3LYP/6-311++G(d,p), and G3MP2 methods. The experimental IR spectra and calculated vibrational frequencies were used to suggest the assignment
of vibrational frequencies of stable conformations. The thermodynamic properties of I–III in the ideal gas state were determined over the temperature range 0–1500 K. A thermodynamic analysis of mutual isomerization
in the gas and liquid phases over the temperature range 298.15–900 K and liquid-phase polymerization of γ- and δ-pentanolactones
and 4-pentenoic acid over the temperature range 298.15–500 K was performed. 相似文献
17.
B. V. Paponov O. V. Shishkin S. V. Shishkina R. I. Zubatyuk A. L. Kalyuzhny V. I. Musatov 《Russian Chemical Bulletin》2008,57(3):622-631
6-Aroyl-7-arylindolo[3,4-jk]phenanthridin-5(4H)-ones (2a–i) were synthesized by heating 3-(2-aryl-2-oxoethylidene)-2,3-dihydroindol-2-ones (1a–i) in DMF. Compounds 2a–i are formed via the dimerization of two molecules of unsaturated ketones 1a–i proceeding as the [2+4] cycloaddition through the formation of intermediate spiro adducts. The further Pfitzinger rearrangement,
decarboxylation, and heteroaromatization afford compounds 2a–i. The structures of the reaction products were established by spectroscopic methods and X-ray diffraction.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 609–618, March, 2008. 相似文献
18.
The chemical reactions between (−)-deprenyl and ·OH or ·OOH were studied using molecular orbital theory, with N,N-dimethylpropargylamine as a model. (−)-Deprenyl was confirmed to be a good radical scavenger. The active site was the acetylenic
part and ·OH- or ·OOH was trapped on either acetylenic carbon. The activation energies were about 10–20 kcal/mol. The resulting ·OH- or ·OOH-adducts, still radicals, trapped further radicals on the remaining carbon of the acetylenic part. The final double trapping
products were at extraordinarily lower energy levels than the original reactants by 50–70 kcal/mol. The secondary transition
states were not detected, suggesting that the reactions occurred at once or in a cascade. Some results with the model system
were verified by the results with the real (−)-deprenyl system.
Received: 6 October 1999 / Accepted: 5 March 2000 / Published online: 21 June 2000 相似文献
19.
Jian-Rong Luo Hong-En Jiang You-Xing Zhao Jun Zhou Jin-Fu Qian 《Chemistry of Natural Compounds》2008,44(1):6-9
To probe the organic constituents of over 2000-year-preserved Populus euphratica found in an ancient tomb, a chemical investigation was undertaken, which led to the isolation of a new compound, 2-(4′-hydroxy-3′-methoxyphenyl)-2-oxoacetamide
(1), together with 12 known compounds (2–13) by column chromatography. Their structures were elucidated on the basis of spectroscopic evidence. It is the first time
that compounds 2–13 were isolated from this plant.
Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 7–9, January–February, 2008. 相似文献
20.
Louis P. Sandjo Vincent Rincheval Bonaventure T. Ngadjui Gilbert Kirsch 《Chemistry of Natural Compounds》2011,47(5):731-734
Two different oxidation reactions (PCC and KMnO4) of stigmasterol gave three products, stigmasta-4,22-dien-3-one (1a), stigmasta-4,22-diene-3,6-dione (1b), and 3-O-acetyl-5β,6β-epoxystigmast-22-ene-3-ol (1c). The cytotoxic activities of hemisynthetic compounds, stigmasterol, and four pentacyclic triterpens 2–5 previously isolated from cultivated and wild Triumfetta cordifolia and identified were investigated against human fibrosarcoma cell line (HT1080). Most of the drugs showed moderate cytotoxic
activity. It was also notice that the triterpene skeleton had a range of number of OH functions in which activity was observed.
Spectroscopic analyses (1H and 13 C NMR) and mass were used to elucidate the structure of hemisynthetic compounds. 相似文献