共查询到20条相似文献,搜索用时 31 毫秒
1.
Mahboubeh Rostami Ahmad Reza Khosropour Valiollah Mirkhani Iraj Mohammadpoor-Baltork Majid Moghadam Shahram Tangestaninejad 《Monatshefte für Chemie / Chemical Monthly》2011,7(1):1175-1180
Abstract
A new and practical promoter system for one-pot, efficient, chemoselective synthesis of 4-arylidene-2-phenyl-5(4H)-oxazolones using [(C14H24N4)2W10O32]-[bmim]NO3 under solvent-free conditions is described. The present work opens up a new and ecofriendly synthetic route to Erlenmeyer–Pl?chl adducts from primary benzyl alcohols in a one-pot operation. 相似文献2.
Ke-Wei Lei Hai-Mei Feng Jun-Long Wen Tian-Pin Shu 《Monatshefte für Chemie / Chemical Monthly》2010,33(3):743-747
Abstract
The 18-metallacrown-6 metallamacrocycle [Fe6(pmshz)6(C4H9NO)6] has been synthesized by the self-assembly reaction of iron ions with N-substituted salicylhydrazide ligands. Six Fe(III) ions and six deprotonated N-propanoyl-4-methylsalicylhydrazide (H3 pmshz) ligands construct a planar 18-membered ring based on Fe–N–N–Fe linkage. Because of the coordination, the ligand enforces the stereochemistry of the Fe(III) ions as a propeller shape with alternating …ΔΛΔΛ… configurations. There is a strong antiferromagnetic exchange interaction between the paramagnetic iron centers. 相似文献3.
An efficient and economical protocol for the synthesis of 5-substituted-1H-tetrazoles from various nitriles and sodium azide is reported using nano TiO2/SO42− as an effective heterogeneous catalyst. A wide variety of aryl nitriles underwent [3 + 2] cycloaddition to afford tetrazoles in good to excellent yields. 相似文献
4.
Three rare earth compounds, KEu[AsS4] (1), K3Dy[AsS4]2 (2), and Rb4Nd0.67[AsS4]2 (3) have been synthesized employing the molten flux method. The reactions of A2S3 (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As2S3, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P21/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with 2∞[Eu(AsS4)]− layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS8] prisms are linked through distorted [AsS4]3− tetrahedra. Each Eu2+ cation is coordinated by two [AsS4]3− units by edge-sharing and bonded to further two [AsS4]3− units by corner-sharing. Compound 2 contains a one-dimensional structure with 1∞[Dy(AsS4)2]3− chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS8] are linked by slightly distorted [AsS4]3− tetrahedra. Each Dy3+ ion is surrounded by four [AsS4]3− moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with 1∞[Nd0.67(AsS4)2]4− chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As4]3− units and four terminal [AsS4]3− groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra. 相似文献
5.
Hongyan Wang Yaoming Xie R. Bruce King Henry F. Schaefer III 《Journal of organometallic chemistry》2008,693(20):3201-3212
Binuclear cycloheptatrienylchromium carbonyls of the type (C7H7)2Cr2(CO)n (n = 6, 5, 4, 3, 2, 1, 0) have been investigated by density functional theory. Energetically competitive structures with fully bonded heptahapto η7-C7H7 rings are not found for (C7H7)2Cr2(CO)n structures having two or more carbonyl groups. This result stands in contrast to the related (CnHn)2M2(CO)n (M = Mn, n = 6; M = Fe, n = 5; M = Co, n = 4) systems. Most of the predicted (C7H7)2Cr2(CO)n structures have bent trihapto or pentahapto C7H7 rings and CrCr distances in the range 2.4–2.5 Å suggesting formal triple bonds. In some cases rearrangement of the heptagonal C7H7 ring to a tridentate cyclopropyldivinyl or tridentate bis(carbene)alkyl ligand is observed. In addition structures with CO insertion into the C7H7–Cr bond are predicted for (C7H7)2Cr2(CO)n (n = 6, 4, 2). The global minima found for the (C7H7)2Cr2(CO)n derivatives for n = 6, 5, and 4 are (η5-C7H7)(OC)2CrCr(CO)4(η1-C7H7), (η3-C7H7)(OC)2CrCr(CO)3(η2,1- C7H7), and (η5-C7H7)2Cr2(CO)4, respectively. The global minima for (C7H7)2Cr2(CO)n (n = 3, 2) have rearranged C7H7 groups. Singlet and triplet structures with heptahapto η7-C7H7 rings are found for the dimetallocenes (η7-C7H7)2Cr2(CO) and (η7-C7H7)2Cr2, with the singlet structures being of much lower energies in both cases. 相似文献
6.
Ceric ammonium nitrate (CAN) is found to be a suitable, inexpensive, and effective non-toxic catalyst for a smooth (3+2) cycloaddition of organic nitriles with NaN3 to afford 5-substituted 1H-tetrazoles in excellent yields. Shorter reaction times, easy work-up, and substantial and pure product formation are the key advantages of the present method. 相似文献
7.
Zhan-Hui Zhang Hong-Juan Wang Xiao-Qian Ren Yan-Yan Zhang 《Monatshefte für Chemie / Chemical Monthly》2009,7(1):1481-1483
Abstract
HBF4/SiO2 was used as an efficient, green, and inexpensive catalytic system for synthesis of 12-aryl or 12-alkyl-8,9,10,12-tetrahydro-11H-benzo[a]xanthen-11-one derivatives via a one-pot three-component reaction of aldehydes, 2-naphthol, and cyclic 1,3-dicarbonyl compounds. The reactions proceeded rapidly at 80 °C under solvent-free conditions and the desired products were obtained in good to excellent yields. 相似文献8.
Zhi-En Lin Jie Zhang Shou-Tian Zheng Qiao-Hua Wei Guo-Yu Yang 《Solid State Sciences》2003,5(11-12):1435-1438
The hydrothermal synthesis, crystal structure and some properties of a zinc phosphite with a neutral cluster, [Zn(2,2′-bipy)]2(H2PO3)4, are reported. This compound crystallizes in the triclinic system of space group P-1 (No. 2), a=8.3067(5) Å, b=8.9545(4) Å, c=10.0893(6) Å, α=95.448(2)°, β=99.7530(10)°, γ=103.461(2)°, V=712.23(7) Å3, Z=1. The cluster consists of 4-membered rings formed by alternating ZnO3N2 square pyramids and H2PO3 pseudo pyramids, with two “hanging” H2PO3 groups attached to each of the Zn centers. The clusters are linked together by extensive multipoint hydrogen bonding involving the phosphite units to form a sheet-like structure. This compound represents the first example of zinc phosphite with P---OH bonds. An intense photoluminescence was observed from this compound upon photoexcitation at 388 nm. 相似文献
9.
Sulata K. Sahu Manjulata Sahu Raman S. Srinivasa Thiagarajan Gnanasekaran 《Monatshefte für Chemie / Chemical Monthly》2012,97(3):1207-1214
Abstract
Heat capacities of PbCrO4(s), Pb2CrO5(s), and Pb5CrO8(s) were measured by differential scanning calorimetry. The measured heat capacities as a function of temperature are expressed as C p <PbCrO4> J K−1 mol−1 = 150.37 + 27.74 × 10−3 T − 2.80 × 106 T −2 (T = 300–750 K), C p <Pb2CrO5> J K−1 mol−1 = 194.55 + 76.09 × 10−3 T − 4.64 × 106 T −2 (T = 300–700 K), and C p <Pb5CrO8> J K−1 mol−1 = 323.35 + 184.80 × 10−3 T − 5.48 × 106 T −2 (T = 300–600 K). From the measured heat capacity data, thermodynamic functions such as enthalpy increments, entropies, and Gibbs energy functions were derived. 相似文献10.
Hassan Hosseini Monfared Azar Mohajeri Ali Morsali Christoph Janiak 《Monatshefte für Chemie / Chemical Monthly》2009,17(1):1437-1445
Abstract
The Mn(II) dicarboxylate coordination polymers [Mn(μ-terephthalate)(H2O)2] n , [Mn(μ-oxalate)(H2O)2] n , and [Mn(μ-d-(−)-tartrate)] n were prepared in water and characterized by FT-IR spectroscopy and CHN analysis. Particles of the terephthalate catalyst were also synthesized, by reaction of terephthalic acid and MnCl2·4H2O by a sonochemical method. The catalytic potential of these coordination polymers as slow-release sources of catalytically active Mn species was tested in the oxidation of cyclooctene to its epoxide in acetonitrile, using hydrogen peroxide as oxygen source. For the terephthalate species the catalytic activity was found to increase with increasing dielectric constant and dipole moment of the solvent (being highest in acetonitrile), with reaction temperature to a maximum at 60 °C, and with an imidazole co-catalyst (highest activity found for a imidazole-to-catalyst molar ratio of 20:1). Good activity with more than 64% conversion in 24 h was obtained for epoxidation of cyclooctene and cyclohexene, whereas low yields only were obtained from aryl-substituted olefins. Some exo versus endo regioselectivity was found for norbornene. 相似文献11.
Xuean Chen Fangping Song Xinan Chang Hegui Zang Weiqiang Xiao 《Journal of solid state chemistry》2009,182(11):3091-3097
Two oxoborates, (Pb3O)2(BO3)2MO4 (M=Cr, Mo), have been prepared by solid-state reactions below 700 °C. Single-crystal XRD analyses showed that the Cr compound crystallizes in the orthorhombic group Pnma with a=6.4160(13) Å, b=11.635(2) Å, c=18.164(4) Å, Z=4 and the Mo analog in the group Cmcm with a=18.446(4) Å, b=6.3557(13) Å, c=11.657(2) Å, Z=4. Both compounds are characterized by one-dimensional chains formed by corner-sharing OPb4 tetrahedra. BO3 and CrO4 (MoO4) groups are located around the chains to hold them together via Pb–O bonds. The IR spectra further confirmed the presence of BO3 groups in both structures and UV–vis diffuse reflectance spectra showed band gaps of about 1.8 and 2.9 eV for the Cr and Mo compounds, respectively. Band structure calculations indicated that (Pb3O)2(BO3)2MoO4 is a direct semiconductor with the calculated energy gap of about 2.4 eV. 相似文献
12.
Combining a temperature variable 22-pole ion trap with a cold effusive beam of neutrals, rate coefficients k(T) have been measured for reactions of CO2+ ions with H, H2 and deuterated analogues. The neutral beam which is cooled in an accommodator to TACC, penetrates the trapped ion cloud with a well-characterized velocity distribution. The temperature of the ions, T22PT, has been set to values between 15 and 300 K. Thermalization is accelerated by using helium buffer gas. For reference, some experiments have been performed with thermal target gas. For this purpose hydrogen is leaked directly into the box surrounding the trap. While collisions of CO2+ with H2 lead exclusively to the protonated product HCO2+, collisions with H atoms form mainly HCO+. The electron transfer channel H+ + CO2 could not be detected (<20%). Equivalent studies have been performed for deuterium. The rate coefficients for reactions with atoms are rather small. Within our relative errors of less than 15%, they do not depend on the temperature of the CO2+ ions nor on the velocity of the atoms (k(T) lays between 4.5 and 4.7 × 10−10 cm3 s−1 with H as target, and 2.2 × 10−10 cm3 s−1 with D). For collisions with molecules, the reactivity increases significantly with falling temperature, reaching the Langevin values at 15 K. These results are reported as k = α (T/300 K)β with α = 9.5 × 10−10 cm3 s−1 and β = −0.15 for H2 and α = 4.9 × 10−10 cm3 s−1 and β = −0.30 for D2. 相似文献
13.
Samia Yahyaoui Walid Rekik Houcine Naïli Tahar Mhiri Thierry Bataille 《Journal of solid state chemistry》2007,180(12):3560-3570
The crystal structures of 1,4-diazabicyclo[2.2.2]octane (dabco)-templated iron sulfate, (C6H14N2)[Fe(H2O)6](SO4)2, were determined at room temperature and at −173 °C from single-crystal X-ray diffraction. At 20 °C, it crystallises in the monoclinic symmetry, centrosymmetric space group P21/n, Z=2, a=7.964(5), b=9.100(5), c=12.065(5) Å, β=95.426(5)° and V=870.5(8) Å3. The structure consists of [Fe(H2O)6]2+ and disordered (C6H14N2)2+ cations and (SO4)2− anions connected together by an extensive three-dimensional H-bond network. The title compound undergoes a reversible phase transition of the first-order at −2.3 °C, characterized by DSC, dielectric measurement and optical observations, that suggests a relaxor–ferroelectric behavior. Below the transition temperature, the compound crystallizes in the monoclinic system, non-centrosymmetric space group Cc, with eight times the volume of the ambient phase: a=15.883(3), b=36.409(7), c=13.747(3) Å, β=120.2304(8)°, Z=16 and V=6868.7(2) Å3. The organic moiety is then fully ordered within a supramolecular structure. Thermodiffractometry and thermogravimetric analyses indicate that its decomposition proceeds through three stages giving rise to the iron oxide. 相似文献
14.
RbAuUSe3, CsAuUSe3, RbAuUTe3, and CsAuUTe3: Syntheses and structure; magnetic properties of RbAuUSe3
The compounds RbAuUSe3, CsAuUSe3, and RbAuUTe3 were synthesized at 1073 K from the reactions of U, Au, Q, and A2Q3 (A=Rb or Cs; Q=Se or Te). The compound CsAuUTe3 was synthesized at 1173 K from the reaction of U, Au, Te, and CsCl as a flux. These isostructural compounds crystallize in the KCuZrS3 structure type in space group Cmcm of the orthorhombic system. The structure consists of layers that contain nearly regular UQ6 octahedra and distorted AuQ4 tetrahedra. The infinite layers are separated by bicapped trigonal prismatic A cations. The magnetic behavior of RbAuUSe3 deviates significantly from Curie–Weiss behavior at low temperatures. For T>200 K, the values of the Curie constant C and the Weiss constant θp are 1.82(9) emu K mol−1 and −3.5(2)×102 K, respectively. The effective magnetic moment μeff is 3.81(9) μB. Formal oxidation states of A/Au/U/Q may be assigned as +1/+1/+4/−2, respectively. 相似文献
15.
Wolfgang Petz Florian
xler Bernhard Neumüller 《Journal of organometallic chemistry》2009,694(25):4094-4099
The cationic complexes [({Ph3P}2C)Ag(C{PPh3}2)]X (2+, X = Cl, BF4) with a linear arrangement of the ligands were obtained from the reaction of C(PPh3)2 (1) with the appropriate AgX in THF. The 31P NMR spectrum of the cation 2+ exhibits a doublet with J(Ag,P) = 15.3 Hz. The cation was also formed when the adduct O2C ← 1 was allowed to react with AgX in CH2Cl2 in the first step as shown by 31P NMR; however, deprotonation of the solvent finally produced the cation (HC{PPh3}2)+, (H1)+ quantitatively. In the absence of coordinating anions, the tricationic complex [({Ph3P}2CH)Ag(CH{PPh3}2)](BF4)3 (3), containing the cation (H1)+ as ligand, could be isolated by reacting AgBF4 with the salt (H1)(BF4). All compounds were characterized by IR and 31P NMR spectroscopy; the structures of the compounds [2]Cl·1.25THF, 3·5CH2Cl2, 3·4C2H4Cl2, and (H1)(BF4) could be established by X-ray analyses. 相似文献
16.
Pavel A. Dub Vladislava A. Levina Elena S. Shubina 《Journal of organometallic chemistry》2011,696(6):1174-6773
Compound trans-PtBr2(C2H4)(NHEt2) (1) has been synthesized by Et2NH addition to K[PtBr3(C2H4)] and structurally characterized. Its isomer cis-PtBr2(C2H4)(NHEt2) (3) has been obtained from 1 by photolytic dissociation of ethylene, generating the dinuclear trans-[PtBr2(NHEt2)]2 intermediate (2), followed by thermal re-addition of C2H4, but only in low yields. The addition of further Et2NH to 1 in either dichloromethane or acetone yields the zwitterionic complex trans-Pt(−)Br2(NHEt2)(CH2CH2N(+)HEt2) (4) within the time of mixing in an equilibrated process, which shifts toward the product at lower temperatures (ΔH° = −6.8 ± 0.5 kcal/mol, ΔS° = 14.0 ± 2.0 e.u., from a variable temperature IR study). 1H NMR shows that free Et2NH exchanges rapidly with H-bonded amine in a 4·NHEt2 adduct, slowly with the coordinated Et2NH in 1, and not at all (on the NMR time scale) with Pt-NHEt2 or -CH2CH2N(+)HEt2 in 4. No evidence was obtained for deprotonation of 4 to yield an aminoethyl derivative trans-[PtBr2(NHEt2)(CH2CH2NEt2)]− (5), except as an intermediate in the averaging of the diasteretopic methylene protons of the CH2CH2N(+)HEt2 ligand of 4 in the higher polarity acetone solvent. Computational work by DFT attributes this phenomenon to more facile ion pair dissociation of 5·Et2NH2+, obtained from 4·Et2NH, facilitating inversion at the N atom. Complex 4 is the sole observable product initially but slow decomposition occurs in both solvents, though in different ways, without observable generation of NEt3. Addition of TfOH to equilibrated solutions of 4, 1 and excess Et2NH leads to partial protonolysis to yield NEt3 but also regenerates 1 through a shift of the equilibrium via protonation of free Et2NH. The DFT calculations reveal also a more favourable coordination (stronger Pt-N bond) of Et2NH relative to PhNH2 to the PtII center, but the barriers of the nucleophilic additions of Et2NH to the C2H4 ligand in 1 and of PhNH2 to trans-PtBr2(C2H4)(PhNH2) (1a) are predicted to be essentially identical for the two systems. 相似文献
17.
1-Allyl-4-aminopyridinium chloride reacts with Cu(NO3)2 · 3H2O in an ethanolic solution under the conditions of ac electrochemical synthesis at copper electrodes to form crystals of compound
[(NH2C5H4N(C3H5))2Cu3Cl3(NO3)2] (I). The crystals of compound I are monoclinic: space group P21/c, Z = 4, a = 25.770(7), b = 7.230(4), c = 12.505(5) ?, β = 92.58(3)°, V = 2328(2) ?3. The direct interaction of 1-allylquinolinium nitrate with Cu(NO3)2 · 3H2O in a methanolic solution in the presence of metallic copper yields crystals of compound [C9H7N(C3H5)Cu(NO3)2] (II). The crystals of compound II are triclinic: space group P
, a = 6.756(3), b = 8.391(4), c = 12.489(5) ?, α = 77.18(3)°, β = 89.48(4)°, γ = 73.32(3)°, V = 662.0(5) ?3. The structure of compound I is built of infinite linear anions: polymeric fragments {(NH2C5H4N(C3H5))2Cu3Cl3(NO3)2}
n
. Each of two copper atoms (Cu(1) and Cu(2)) π-coordinates the C=C bonds of the allyl groups of the 1-allyl-4-aminopyridinium
cations, the oxygen atom of the nitrate ions, and two chlorine atoms. The third copper atom Cu(3) is linearly linked with
two chlorine atoms. Particular polymeric fragments are additionally joined by the N-H…O, C-H…O, C-H…Cl hydrogen bonds. The
crystal structure of compound II is built-up of the isolated L2Cu2(NO3)4 fragments (L is the 1-allylquinolinium cation). The metal atom is localized in the trigonal pyramidal coordination environment
of three oxygen atoms of the nitrate ions and of the C=C bond of the allyl group of the cation. The particular L2Cu2(NO3)4 fragments are additionally joined by the C-H…O hydrogen bonds.
Original Russian Text ? A.V. Pavlyuk, T. Lis, M.G. Mys’kiv, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No.
6, pp. 458–462. 相似文献
18.
19.
An efficient one-pot, convenient catalysis for the synthesis of 5-substituted-1H-tetrazoles is reported. The [3+2] cycloaddition involves various nitriles, sodium azide in refluxing DMF and AgNO3 as catalyst to give corresponding 5-substituted-1H-tetrazoles in good to excellent yields. It is expected that the reaction proceeds via in situ formation of a silver azide species, which participates in coordination of nitrile moiety followed by cycloaddition of azide ion to give tetrazole. 相似文献
20.
Trinath Mishra Christian Schwickert Rainer P?ttgen 《Monatshefte für Chemie / Chemical Monthly》2011,15(2):973-978