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1.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015)
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MM. J. Duflos D. Letouz G. Queguiner P. Pastour 《Journal of heterocyclic chemistry》1973,10(6):1083-1084
This communication describes the synthesis of l-methyl-2,3-diformylpyrrole. This new compound is used to prepare a new heterocycle, l-methylcyclohepta[b]pyrrol-6-one and thus allows a new synthesis of l-methylpyrrolo[2,3-d]pyridazine. 相似文献
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The crystal structures of the 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, TCNQF(4), electron transfer salts of meso-tetraphenylporphinatomagnesium(II), [MgTPP][TCNQF(4)].PhMe and [MgTPP][TCNQF(4)].3(1,2-C(6)H(4)Cl(2)), and meso-tetrakis(3,4,5-trimethoxyphenyl)porphinatomagnesium(II), [MgT(3,4,5-OMe)PP][TCNQF(4)].3(1,2-C(6)H(4)Cl(2)), provide the first structurally characterized examples of 1-D metal-radical chains involving [Mg(II)(porphyrin(*))](+). These salts possess [TCNQF(4)](*-) stabilized by trans-mu-coordination to Mg(II) and exhibit nu(CN) at 2199 and 2177, 2212 and 2187, and 2194 and 2172 cm(-1), respectively. The [TCNQF(4)](*-) species is planar and bridges two cations with MgN distances of 2.266(16), 2.221(2), and 2.276(3) A, respectively, which are shorter than the MnN 2.321(3) A distance observed for [MnT(3,4,5-OMe)PP][TCNQF(4)].3(1,2-C(6)H(4)Cl(2)). The room-temperature effective moments for [MgTPP][TCNQF(4)].xS (S = PhMe and 1,2-C(6)H(4)Cl(2)) and [MgTPP][C(4)(CN)(6)].PhMe are consistent with the calculated spin only value of 2.45 micro(B) with weak antiferromagnetic coupling (J(intra)/k(B) approximately -2.9 K; H = -2JSa.Sb) for these [TCNQF(4)](*-) salts and for this [C(4)(CN)(6)](*-) salt (J(intra)/k(B) approximately -0.8 K) on the basis of fits to several models. The coupling is significantly reduced with respect to that of the Mn analogues due to lack of spin on the metal site for [Mg(II)(por(*))](+). The antiferromagnetic coupling is enhanced for [MgT(3,4,5-OMe)PP][TCNQF(4)] with respect to [MgTPP][TCNQF(4)] as [TCNQF(4)](*-) gets closer to the [Mg(II)(por(*))](+) plane, which leads to greater interactions and coupling. 相似文献
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Valery Belakhov Mark Botoshansky Timor Baasov 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):m450-m452
The hexopyranosyl ring of the title compound, [Hg(CH3)(C9H15O7S)], adopts the 4C1 chair conformation, and the anomeric configuration of the thiomethylmercury linkage is β. The compound exists as two symmetry‐independent conformers, A and B, within the unit cell, and each shows an almost linear S—Hg—C arrangement. Most of the bond distances and angles in A and B are similar, although a marked difference exists in the side‐chain conformation. Weak secondary intramolecular (between Hg and ring O) and intermolecular (between A and B conformers) interactions are documented. 相似文献
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Lukyanenko NG Kirichenko TI Lyapunov AY Mazepa AV Simonov YA Fonari MS Botoshansky MM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):262-270
The first three representatives of the new family of oxacyclophanes incorporating two 2,7-dioxyfluorenone fragments, connected by [-CH(2)CH(2)O-](m) spacers (m=2-4), have been synthesized. The yield of the smallest oxacyclophane (m=2) is considerably higher with respect to the larger ones (m=3 and m=4), which are formed in comparable yields. Molecular modeling and NMR spectra analysis of the model compounds suggest that an essential difference in oxacyclophanes yields is caused by formation of quasi-cyclic intermediates, which are preorganized for macrocyclization owing to intramolecular pi-pi stacking interactions between the fluorenone units. The solid-state structures of these oxacyclophanes exhibit intra- and intermolecular pi-pi stacking interactions that dictate their rectangular shape in the fluorenone backbone and crystal packing of the molecules with the parallel or T-shape arrangement. The crystal packing in all cases is also sustained by weak C--HO hydrogen bonds. FAB mass spectral analysis of mixtures of the larger oxacyclophanes (m=3 and m=4) and a paraquat moiety revealed peaks corresponding to the loss of one and two PF(6) (-) counterions from the 1:1 complexes formed. However, no signals were observed for complexes of the paraquat moiety with the smaller oxacyclophane (m=2). Computer molecular modeling of complexes revealed a pseudorotaxane-like incorporation of the paraquat unit, sandwiched within a macrocyclic cavity between the almost parallel-aligned fluorenone rings of the larger oxacyclophanes (m=3 and m=4). In contrast to this, only external complexes of the smallest oxacyclophane (m=2) with a paraquat unit have been found in the energy window of 10 kcal mol(-1). 相似文献
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Hellena Taycher Mark Botoshansky Vitaly Shteiman Menahem Kaftory 《Supramolecular chemistry》2013,25(1):181-192
Abstract 2-Anilino-4,6-dimethoxy-1,3,5-triazine (13), 2-anilino-4,6-diethoxy-1,3,5-triazine (14), 2-(2′-nitoanilino) 4,6-dimethoxy-1,3,5-triazine (15) undergo alkyl rearrangement in the liquid-state, while 2-(4′-nito-anilino) 4,6-dimethoxy-1,3,5-triazine (16) undergoes methyl rearrangement in the solid-state. The crystal structure and thermal behavior of these compounds are described. 13 crystallizes in monoclinic P21/c space group, a = 11.030(4), b = 6.345(4), c = 16.315(4) Å, β = 90.76(3)°. The calculated density for Z = 4 is 1.351 Mg/m3. The number of unique reflections collected is 2092, and the final R = 0.0643 [I > 2σ(I)]. 14 crystallizes in triclinic P-1 space group, a = 7.700(2), b = 9.723(3), c = 10.154(3) Å, α = 78.78(3), β = 70.32(3), γ = 73.67(3)°. The calculated density for Z = 2 is 1.266 Mg/m3. The number of unique reflections collected is 2401, and the final R = 0.0561 [I > 2σ(I)]. 15 crystallizes in monoclinic P21/m space group, a = 11.020(3), b = 6.600(2), c = 8.409(3) Å, β = 99.72(3)°. The calculated density for Z = 2 is 1.527 Mg/m3. The number of unique reflections collected is 1153, and the final R = 0.0502 [I > 2σ(I)]. 16 crystallizes in monoclinic P21/c space group, a = 7.499(3), b = 21.846(5), c = 7.895(3) Å, β = 115.42(3)°. The calculated density for Z = 4 is 1.576 Mg/m3. The number of unique reflections collected is 2036, and the final R = 0.0757 [I > 2σ(I)]. 相似文献
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