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121.
Summary The reactions of 2,2-biquinoline(biq) with M(PhCN)2X2 (M=Pd; X=Cl or Br; M=Pt, X=Cl, Br or I), K2PtCl4 and RhCl3·3H2O and of 2-(2-pyridyl)quinoline (pq) with K2PtCl4 and RhCl3·3H2O have been investigated. The isolated complexescis-[Pd(biq)X2] (X=Cl or Br),cis-[Pt(biq)Cl2],cis-[Pt(biq)Cl2]·H2O,trans-[Pt(biq)2Br2]·5H2O, [Pt3(biq)2I6],mer-[Rh(biq)Cl3-(H2O)] andmer-[Rh(pq)Cl3(H2O)] have been characterized by elemental analyses, conductivity measurements, i.r., electronic, and1H n.m.r. spectra. The reaction of pq with K2PtCl4 in 1M H2SO4 gave the salt 2-(2-pyridyl) quinolinium tetrachloroplatinate(II) pentahydrate, (pqH)2[PtCl4]·5H2O; when the reaction was carried out in aqueous acetone,cis-[Pt(pq)Cl2] was obtained. A new method for the synthesis ofcis-[Rh(biq)2X2]X (X=Cl or Br) is described; both compounds have been further characterized by1H n.m.r. 相似文献
122.
Reversible Mechanical Interlocking of D‐Shaped Molecular Karabiners bearing Coordination‐Bond Loaded Gates: Route to Self‐Assembled [2]Catenanes 下载免费PDF全文
Soumyakanta Prusty Dr. Shobhana Krishnaswamy Sreenivasulu Bandi Dr. Baby Chandrika Dr. Jingwei Luo Prof. Dr. J. Scott McIndoe Prof. Dr. Garry S. Hanan Prof. Dr. Dillip Kumar Chand 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15174-15187
Complexation of 1,4‐phenylenebis(methylene) diisonicotinate, L1 , with cis‐protected PdII components, [Pd( L′ )(NO3)2], in an equimolar ratio yielded binuclear complexes, 1 a – d of [Pd2( L′ )2( L1 )2](NO3)4 formulation where L′ stands for ethylenediamine (en), tetramethylethylenediamine (tmeda), 2,2′‐bipyridine (bpy), and phenanthroline (phen). The combination of 4,4′‐bipyridine, L2 , with the cis‐protected PdII units is known to yield molecular squares, 2 a – d . However, 2 b – d coexist with the corresponding molecular triangles, 3 b – d . Combination of an equivalent each of the ligands L1 and L2 with two equivalents of cis‐protected PdII components in DMSO resulted in the D ‐shaped heteroligated complexes [Pd2( L′ )2( L1 )( L2 )](NO3)4, 4 a – d . Two units of the D ‐shaped complexes interlock, in a concentration dependent fashion, to form the corresponding [2]catenanes [Pd2( L′ )2( L1 )( L2 )]2(NO3)8, 5 a – d under aqueous conditions. Crystal structures of the macrocycle [Pd2(tmeda)2( L1 )( L2 )](PF6)4, 4 b′′ , and the catenane [Pd2(bpy)2( L1 )( L2 )]2(NO3)8, 5 c , provide unequivocal support for the proposed molecular architectures. 相似文献
123.
Lanthanoid/Alkali Metal β‐Triketonate Assemblies: A Robust Platform for Efficient NIR Emitters 下载免费PDF全文
Brodie L. Reid Dr. Stefano Stagni Dr. Joanna M. Malicka Dr. Massimo Cocchi Dr. Alexandre N. Sobolev Prof. Brian W. Skelton Dr. Evan G. Moore Prof. Garry S. Hanan Prof. Mark I. Ogden Dr. Massimiliano Massi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18354-18363
The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae ? HOEt)( L )4]2 (Ln=Eu3+, Er3+, Yb3+; Ae=Na+, K+, Rb+). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near‐infrared (NIR)‐emitting assemblies of Yb3+ and Er3+ showed remarkably efficient emission, characterized by significantly longer excited‐state lifetimes (τobs≈37–47 μs for Yb3+ and τobs≈4–6 μs for Er3+) when compared with the broader family of lanthanoid β‐diketonate species, even in the case of perfluorination of the ligands. The Eu3+ assemblies show bright red emission and a luminescence performance (τobs≈0.5 ms, ${{\Phi}{{{\rm L}\hfill \atop {\rm Ln}\hfill}}}$ ≈35–37 %, ηsens≈68–70 %) more akin to the β‐diketonate species. The results highlight that the β‐triketonate ligand offers a tunable and facile system for the preparation of efficient NIR emitters without the need for more complicated perfluorination or deuteration synthetic strategies. 相似文献
124.
Dr. Dario Formenti Dr. Rita Mocci Dr. Hanan Atia Dr. Sarim Dastgir Dr. Muhammad Anwar Dr. Stephan Bachmann Dr. Michelangelo Scalone Dr. Kathrin Junge Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15589-15595
Cobalt-doped hybrid materials consisting of metal oxides and carbon derived from chitin were prepared, characterized and tested for industrially relevant nitrile hydrogenations. The optimal catalyst supported onto MgO showed, after pyrolysis at 700 °C, magnesium oxide nanocubes decorated with carbon-enveloped Co nanoparticles. This special structure allows for the selective hydrogenation of diverse and demanding nitriles to the corresponding primary amines under mild conditions (e.g. 70 °C, 20 bar H2). The advantage of this novel catalytic material is showcased for industrially important substrates, including adipodinitrile, picolinonitrile, and fatty acid nitriles. Notably, the developed system outperformed all other tested commercial catalysts, for example, Raney Nickel and even noble-metal-based systems in these transformations. 相似文献
125.
Nag S Ferreira JG Chenneberg L Ducharme PD Hanan GS La Ganga G Serroni S Campagna S 《Inorganic chemistry》2011,50(1):7-9
Two new bidentate ligands (1 and 2) with bicyclic guanidine moieties were synthesized and attached to a Ru(II)(bpy)(2) core (bpy = 2,2'-bipyridine) to afford complexes 3 and 4, which were characterized by spectroscopic and electrochemical methods. Complex 4 was further characterized by X-ray crystallography. In cyclic voltammetric studies, both complexes show a Ru(II/III) couple, which is 500 mV less positive than the Ru(II/III) couple of Ru(bpy)(3)(2+). The (1)MLCT and (3)MLCT states of 3 (560 nm/745 nm) and 4 (550 nm/740 nm) are significantly red-shifted with respect to Ru(bpy)(3)(2+) (440 nm/620 nm). Compounds 3 and 4 exhibit emission from a Ru(II)-to-bpy (3)MLCT state, which is rarely the emitting state at λ > 700 nm in [Ru(bpy)(2)(N-N)](2+) complexes. 相似文献
126.
Werrett MV Chartrand D Gale JD Hanan GS MacLellan JG Massi M Muzzioli S Raiteri P Skelton BW Silberstein M Stagni S 《Inorganic chemistry》2011,50(4):1229-1241
The synthesis, structural, and photophysical properties of a novel family of neutral fac-[Re(N(∧)N)(CO)(3)(L)] complexes, where N(∧)N is either 2,2'-bipyridine or 1,10-phenanthroline and L is a para functionalized 5-aryltetrazolate [namely, 5-phenyltetrazolate (Tph(-)), 4-(tetrazolate-5-yl)benzaldehyde (Tbdz(-)), 5-(4-acetylphenyl)tetrazolate (Tacy(-)), and methyl 4-(tetrazolate-5-yl)benzoate (Tmeb(-))] are reported. The complexes were prepared by direct addition of the corresponding tetrazolate anion to the acetonitrile solvated fac-[Re(N(∧)N)(CO)(3)](+) precursor. NMR data demonstrate that the coordination of the metal fragment is regiospecific at the N2 atom of the tetrazolate ring. These conclusions are also supported by X-ray structural determinations. Photophysical data were obtained in diluted and deaerated dichloromethane solutions displaying broad and structureless profiles with emission maxima ranging from 566 to 578 nm. The absorption profiles indicate the presence of higher energy intraligand (IL) π-π* transitions and lower energies ligand-to-ligand charge transfer (LLCT) and metal-to-ligand charge transfer (MLCT). As the last two transitions are mixed, they are better described as a metal-ligand-to-ligand charge transfer (MLLCT), a result that is also supported by density functional theory (DFT) calculations. The complexes show excited state lifetime values ranging from 102 to 955 ns, with associated quantum yield between 0.012 and 0.099. Compared to the parent neutral chloro or bromo [Re(N(∧)N)(CO)(3)X], the complexes show a slightly improved performance because of the π accepting nature of the tetrazolato ligand. The metal-to-ligand backbonding is in fact depleting the Re center of electron density, thus widening the HOMO-LUMO gap and reducing the non-radiative decay mechanism in accordance with the energy gap law. Finally, the electron-withdrawing or donating nature of the substituent on the phenyltetrazolato ligand allows the fine-tuning of the photophysical properties. 相似文献
127.
Ludwig Chenneberg Janaina G. Ferreira Garry S. Hanan 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(4):m81-m84
The title compound, [4′‐(4‐bromophenyl)‐2,2′:6′,2′′‐terpyridine]chlorido(trifluoromethanesulfonato)copper(II), [Cu(CF3O3S)Cl(C21H14BrN3)], is a new copper complex containing a polypyridyl‐based ligand. The CuII centre is five‐coordinated in a square‐pyramidal manner by one substituted 2,2′:6′,2′′‐terpyridine ligand, one chloride ligand and a coordinated trifluoromethanesulfonate anion. The Cu—N bond lengths differ by 0.1 Å for the peripheral and central pyridine rings [2.032 (2) (mean) and 1.9345 (15) Å, respectively]. The presence of the trifluoromethanesulfonate anion coordinated to the metal centre allows Br...F halogen–halogen interactions, giving rise to the formation of a dimer about an inversion centre. This work also demonstrates that the rigidity of the ligand allows the formation of other types of nonclassical interactions (C—H...Cl and C—H...O), yielding a three‐dimensional network. 相似文献
128.
A facile and highly efficient protocol for the synthesis of 1,8-dioxo-octahydroxanthene derivatives was achieved through cascade Knoevenagel-Michael condensations and cyclo-dehydration reaction utilizing tetrachlorosilane(TCS) as catalyst under mild conditions.Reaction of the titled compounds with TCSNaN3 to give novel functionalized pyrano[3,2-c]tetrazolo[1,5-a]azepine derivatives is also described. 相似文献
129.
Wang J Fang YQ Bourget-Merle L Polson MI Hanan GS Juris A Loiseau F Campagna S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(33):8539-8548
A new family of ruthenium(II) complexes with multichromophoric properties was prepared based on a "chemistry-on-the-complex" synthetic approach. The new compounds are based on tridentate chelating sites (tpy-type ligands, tpy=2,2':6',2'-terpyridine) and most of them carry appended anthryl chromophores. Complexes 2 a and 2 b were synthesized through the Pd-catalyzed Suzuki coupling reaction between 9-anthrylboronic acid and the chloro ligands on the presursor species 1 a and 1 b, respectively. The monocoupling product 2 c was also synthesized as the starting complex for a dimetallic complex under optimized Suzuki coupling conditions. The palladium(0)-catalyzed homocoupling reaction on complexes 1 a and 2 c led to dimetallic Ru(II) species 2 d and 2 e, respectively. The solid structures of complexes 2 a and 2 b were characterized by X-ray diffraction. The absorption spectra, redox behavior, luminescence properties (both at room temperature and at 77 K), and transient absorption spectra and decays of 2 a-e were investigated. The absorption spectra of all new species are dominated by ligand-centered (LC) bands in the UV region and metal-to-ligand charge-transfer (MLCT) bands in the visible region. The new compounds undergo reversible metal-centered oxidation processes and several ligand-centered reduction processes, which have been assigned to specific sites. The complexes exhibit luminescence both at room temperature in fluid solution and at 77 K in rigid matrices; the emission was attributed to (3)MLCT states at room temperature and to the lowest-lying anthracene triplet ((3)An) at low temperature, except for 2 c, which does not contain any anthryl chromophore and whose low temperature emission is also of MLCT origin. The luminescence lifetimes of complexes 2 a-d showed that multichromophoric behavior occurs in these species, allowing the luminescence lifetime of the Ru(II)-based chromophores to be prolonged to the microsecond timescale, with the anthryl groups behaving as energy-storage elements for the repopulation of the (3)MLCT state. Nanosecond transient-absorption spectroscopy confirmed the equilibration process between the triplet MLCT and An levels at room temperature. Thermodynamic and kinetic factors governing the equilibration time and the lifetime of the equilibrated excited state are discussed. 相似文献
130.
Hanan Sa’adi 《Journal of Physics and Chemistry of Solids》2008,69(10):2457-2464
We report density functional theory (DFT) calculations for the surface energy, work function, and interlayer spacings for Ir(1 1 1), Ir(1 0 0), and Ir(1 1 0) surfaces using pseudopotential method and plane waves basis set. We investigate the convergence of the surface energy as a function of the number of layers in the slab for the Ir(1 0 0) surface. The results show that the surface energies calculated using the bulk total energies obtained by a fit to a series of slab total energies converge within 0.01 J/m2. We also investigate the convergence of the work function and interlayer spacings as a function of the number of layers in the slab, for the Ir(1 0 0) surface. Employing the local-density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange correlation functional, we obtained a very good agreement of the calculated surface energies and work functions with experimental results. For the studied surfaces, the calculations give interlayer relaxations that are in an excellent agreement with available low-energy electron diffraction (LEED) analysis. Furthermore, we discuss the performance of the LDA and GGA for the exchange correlation functional in describing the various surface properties. The results show that calculations using GGA give results that are in a better agreement with experiment than the LDA. 相似文献