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621.
Tamao Ishida 《Tetrahedron letters》2006,47(30):5265-5268
Molecular wire, diacetylene-linked porphyrin dimer 6 having terminal alkenes, was synthesized. Porphyrin dimer 6 formed the 1:1 double-stranded ladder complex with 1,4-diazabicyclo[2.2.2]octane (DABCO). The co-planar stacked two porphyrin molecular wires in the ladder complex were connected by olefin metathesis in the presence of the Grubbs catalyst in order to make a covalently bonded tubular nanostructure. The obtained molecular tube 7 was characterized by 1H, 13C NMR spectroscopy, and MALDI-TOF MS spectrometry. 相似文献
622.
Dyads of a N-confused porphyrin (NCP) moiety covalently linked to a porphyrin free-base (H2P) or a zinc(II) porphyrinate (ZnP) moiety via a flexible alkyl chain of variable length have been synthesized. Photoluminescence study demonstrated an efficient excitation energy transfer from H2P/ZnP moiety to the NCP moiety. Measurement of the near-IR emission of singlet oxygen produced by these dyads via photosensitization showed that the NCP-ZnP dyads (ФΔ = (0.61-0.65) ± 0.13) were better 1O2 generators than the NCP-P dyads (ФΔ = (0.36-0.41) ± 0.08). 相似文献
623.
通过轴向配位反应,将四苯基卟啉锌(ZnTPP)键合在4-乙烯基吡啶(4VP)与苯乙烯(St)共聚物P(4VP-co-St)的侧链,制得了卟啉功能化的大分子ZnTPP-P(4VP-co-St).通过FTIR与1H-NMR对其化学结构进行了表征,重点研究了时间、温度对轴配过程的影响,以及大分子轴配化合物ZnTPP-P(4VP-co-St)的谱学性能,对其光物理行为进行了较为深入的分析.研究结果表明,以共聚物P(4VP-co-St)的吡啶侧基为配体,通过轴向配位反应可顺利地制备卟啉功能化的大分子ZnTPP-P(4VP-co-St),且温度越低,键合量越大.该大分子具有类似于ZnTPP的特征电子吸收光谱与荧光发射光谱,同时也显示出轴向配位的特征.与小分子ZnTPP相比,ZnTPP-P(4VP-co-St)的吸收光谱和发射光谱都发生了明显的红移.大分子轴配化合物ZnTPP-P(4VP-co-St)的光物理行为也呈现出一定程度的高分子效应,随着大分子链中ZnTPP键合量的增大,相近的ZnTPP侧链单元之间会发生能量转移,使荧光发射强度有所减弱. 相似文献
624.
SONG Yan ;ZHAN Nai-qian ;YU Miao ;YANG Qing-biao ;ZHANG Chao-qun ;WANG Heng-guo ;LI Yao-xian 《高等学校化学研究》2008,24(6):722-725
Poly(4-vinylpyridine)(P4-VP) nanofiber and fluoresent poly(4-vinylpyridine)/porphyrin(P4-VP/TPPA) nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dimethylformamide (DMF) electrospinning solutions on the morphology of P4-VP nanofiber was investigated and it was found that the average diameter of the nanofiber of P4-VP/DMF increased with the increase of the concentration of the spinning solution. After the addition of TPPA to the P4-VP/DMF spinning solution, the diameter of P4-VP/TPPA nanofiber became even due to the increase of the conductivity of the P4-VP/DMF-TPPA solution. The photoluminescent(PL) spectral analysis indicates that the emission peak position of P4-VP/TPPA nanofiber is almost the same as that of pure TPPA at about 650 nm without peak shift, and when it was stored for 20 days, the emission peak of P4-VP/TPPA nanofiber is also at 650 nm, indicating that the fluorescent property of P4-VP/TPPA nanofiber is stable. Fourier-transform iufrared(FTIR) spectrum confirms the chemical composition of the resulting P4-VP/TPPA composite nanofiber. 相似文献
625.
Dr. Marcin A. Majewski Wojciech Stawski Dr. Jeff M. Van Raden Michael Clarke Jack Hart Dr. James N. O'Shea Dr. Alex Saywell Prof. Harry L. Anderson 《Angewandte Chemie (International ed. in English)》2023,62(18):e202302114
Rings of porphyrins mimic natural light-harvesting chlorophyll arrays and offer insights into electronic delocalization, providing a motivation for creating larger nanorings with closely spaced porphyrin units. Here, we demonstrate the first synthesis of a macrocycle consisting entirely of 5,15-linked porphyrins. This porphyrin octadecamer was constructed using a covalent six-armed template, made by cobalt-catalyzed cyclotrimerization of an H-shaped tolan with porphyrin trimer ends. The porphyrins around the circumference of the nanoring were linked together by intramolecular oxidative meso-meso coupling and partial β-β fusion, to give a nanoring consisting of six edge-fused zinc(II) porphyrin dimer units and six un-fused nickel(II) porphyrins. STM imaging on a gold surface confirms the size and shape of the spoked 18-porphyrin nanoring (calculated diameter: 4.7 nm). 相似文献
626.
Davide Ranieri Dr. Alberto Privitera Dr. Fabio Santanni Dr. Karolina Urbanska Dr. Grant J. Strachan Dr. Brendan Twamley Prof. Dr. Enrico Salvadori Dr. Yu-Kai Liao Prof. Dr. Mario Chiesa Prof. Dr. Mathias O. Senge Prof. Dr. Federico Totti Prof. Dr. Lorenzo Sorace Prof. Dr. Roberta Sessoli 《Angewandte Chemie (International ed. in English)》2023,62(48):e202312936
In the development of two-qubit quantum gates, precise control over the intramolecular spin-spin interaction between molecular spin units plays a pivotal role. A weak but measurable exchange coupling is especially important for achieving selective spin addressability that allows controlled manipulation of the computational basis states |00⟩ |01⟩ |10⟩ |11⟩ by microwave pulses. Here, we report the synthesis and Electron Paramagnetic Resonance (EPR) study of a heterometallic meso-meso (m-m) singly-linked VIVO−CuII porphyrin dimer. X-band continuous wave EPR measurements in frozen solutions suggest a ferromagnetic exchange coupling of ca. 8 ⋅ 10−3 cm−1. This estimation is supported by Density Functional Theory calculations, which also allow disentangling the ferro- and antiferromagnetic contributions to the exchange. Pulsed EPR experiments show that the dimer maintains relaxation times similar to the monometallic CuII porphyrins. The addressability of the two individual spins is made possible by the different g -tensors of VIV and CuII-ions, in contrast to homometallic dimers where tilting of the porphyrin planes plays a key role. Therefore, single-spin addressability in the heterometallic dimer can be maintained even with small tilting angles, as expected when deposited on surface, unlocking the full potential of molecular quantum gates for practical applications. 相似文献
627.
Abhijeet Singh Jagmeet Singh Prof. Dr. Mahendra Nath 《European journal of organic chemistry》2023,26(4):e202201319
A facile synthetic strategy for the synthesis of a new series of β,β’-fused 2-arylpyrimido[4,5-b]porphyrins has been developed by using condensation cyclization reaction with ammonia. 2-Aroylamino-3-formylporphyrins were synthesized from 2-aroylaminoporphyrins under Vilsmeier–Haack reaction conditions, which were then efficiently converted to the corresponding 2-arylpyrimido[4,5-b]-5,10,15,20-tetrakis(4-chlorophenyl)-porphyrins via a condensation cyclization reaction. The nickel(II), copper(II), free-base and zinc(II) analogues of 2-arylpyrimido[4,5-b]porphyrins were successfully synthesized in 65–72 % yields and structurally characterized on the basis of spectral data analysis. On photophysical evaluation, 2-arylpyrimido[4,5-b]porphyrins demonstrated a 12–19 nm bathochromic shift in their electronic absorption spectra and up to 10 nm red shift in their emission spectra as compared to the simple meso-(tetrakis(4-chlorophenyl))porphyrins due to the extended π-conjugation. 相似文献
628.
Dr. Yannan Liu Dr. Fulu Zheng Haojie Dai Chuanshuang Chen Yajing Chen Dr. Haolin Wu Prof. Chunyang Yu Prof. Yiyong Mai Prof. Thomas Frauenheim Prof. Yongfeng Zhou 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302126
Supramolecular self-assembly is a promising strategy for stabilizing the photo-sensitive components in photocatalysis. However, the underlying correlation between the enhanced photostability and supramolecular structure at the molecular level has not yet been fully understood. Herein, we develop a biomimetic vesicular membrane-based polyporphyrin photocatalyst exhibiting excellent photocatalytic stability with at least activity time of 240 h in hydrogen generation. Time-domain ab initio modelling together with transient absorption spectroscopy, visual frontier orbitals and Gibbs free energy calculation disclose that the ordered aggregation of porphyrin units in the vesicle membrane facilitates “hot” electron relaxation and the rapid dissipation of photo-generated charges, thereby contributing to the longevity. This work deepens the molecular-level understanding on photostability and photocatalytic mechanism of supramolecular photocatalysts. 相似文献
629.
Qingxian Kuang Ruoyu Zhang Zhenzhen Zhou Can Liao Prof. Dr. Shunjie Liu Prof. Dr. Xuesi Chen Prof. Dr. Xianhong Wang 《Angewandte Chemie (International ed. in English)》2023,62(35):e202305186
Ultra-low molecular weight (ULMW) CO2-polyols with well-defined hydroxyl end groups represent useful soft segments for the preparation of high-performance polyurethane foams. However, owing to the poor proton tolerance of catalysts towards CO2/epoxide telomerization, it remains challenging to synthesize ULMW yet colorless CO2-polyols. Herein, we propose an immobilization strategy of constructing supported catalysts by chemical anchoring of aluminum porphyrin on Merrifield resin. The resulting supported catalyst displays both extremely high proton tolerance (≈8000 times the equivalents of metal centers) and independence of cocatalyst, affording CO2-polyols with ULMW (580 g mol−1) and high polymer selectivity (>99 %). Moreover, the ULMW CO2-polyols with various architectures (tri-, quadra-, and hexa-arm) can be obtained, suggesting the wide proton universality of supported catalysts. Notably, benefiting from the heterogeneous nature of the supported catalyst, colorless products can be facilely achieved by simple filtration. The present strategy provides a platform for the synthesis of colorless ULMW polyols derived from not only CO2/epoxides, but also lactone, anhydrides etc. or their combinations. 相似文献
630.
Prof. Dr. Shi-Chao Qi Yong-Lan Liu Xiao-Jie Lu Yun-Jie Zhao Jia-Xin Li Prof. Dr. Xiao-Qin Liu Prof. Dr. Lin-Bing Sun 《Angewandte Chemie (International ed. in English)》2023,62(27):e202304367
The photo-responsive adsorption has emerged as a vibrant area, but its current methodology is limited by the well-defined photochromic units and their molecular deformation driven by photo-stimuli. Herein, a methodology of nondeforming photo-responsiveness is successfully exploited. With the exploiting agent of Cu-TCPP framework assembled on the graphite and strongly interacted with it, the sorbent generates two kinds of adsorption sites, over which the electron density distribution of the graphite layer can be modulated at the c-axis direction, which can further evolve due to photo-stimulated excited states. The excited states are stable enough to meet the timescale of microscopic adsorption equilibrium. Independent of the ultra-low specific surface area of the sorbent (20 m2 g−1), the CO adsorption capability can be improved from 0.50 mmol g−1 at the ground state to 1.24 mmol g−1 (0 °C, 1 bar) with the visible light radiation, rather than the photothermal desorption. 相似文献