共查询到20条相似文献,搜索用时 15 毫秒
1.
正磁性和极性是功能材料中两个非常重要的性质~1。单一的磁化或者极化强度调控可以通过客体分子、压力、光和热等外界刺激实现,其中光调控以其操控简便、响应快速等特点成为研究热点。但是到目前为止,在单个分子中同时实现磁化和极化调控的化合物中,光诱导磁性的改变停留于单向调控的阶段,对极性的调控也仅限于理论推导层面~2。实现不同光照条件对材料的双向调控以及实验观测磁性和极性的改变仍是一个很大的挑战。 相似文献
2.
Junqiu Li Dr. Shuqi Wu Dr. Shengqun Su Dr. Shinji Kanegawa Prof. Osamu Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(15):3259-3263
Some cyanide-bridged complexes are known for exhibiting slow magnetic relaxation behavior in a light-induced metastable state. Herein, an unexpected reverse effect is observed for the first time in the S= {FeIILS-CoIIILS-FeIIILS} (HS=high spin, LS=low spin) ground state of a novel V-shaped trinuclear cyanide-bridged {Fe2Co} complex. In this complex, light-switchable iron-cobalt charge transfer with repeatable off/on switching of slow magnetic relaxation is discovered upon alternating laser irradiation at 785 and 560 nm. An important characteristic of the present compound is that the S= ground state exhibits slow magnetic relaxation before irradiation, whereas this is accelerated after irradiation. This is different from the typical behavior, where the light-induced metastable state exhibits slow magnetic relaxation. 相似文献
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Wen Wen Dr. Yin-Shan Meng Dr. Cheng-Qi Jiao Qiang Liu Hai-Lang Zhu Prof. Ya-Ming Li Prof. Hiroki Oshio Prof. Tao Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(38):16535-16539
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal-to-metal charge transfer (MMCT) and spin-crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a FeII-triazole moiety and generates a mixed-valence complex {[(Tp4-Me)FeIII(CN)3]9[FeII4(trz-ph)6]}⋅[Ph3PMe]2⋅[(Tp4-Me)FeIII(CN)3] ( 1 ; trz-ph=4-phenyl-4H-1,2,4-triazole). Moreover, MMCT occurs between FeIII and one of the FeII sites after heat treatment, resulting in the generation of a new phase, {[(Tp4-Me)FeII(CN)3][(Tp4-Me)FeIII(CN)3]8 [FeIIIFeII3(trz-ph)6]}⋅ [Ph3PMe]2⋅[(Tp4-Me)FeIII(CN)3] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two-step SCO behavior of 1 into one-step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin-transition materials with accessible multi-electronic states. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7771-7776
It is a challenge to reversibly switch both magnetism and polarity using light irradiation. Herein we report a linear Fe2Co complex, whereby interconversion between FeIIILS(μ‐CN)CoIIHS(μ‐NC)FeIIILS (LS=low‐spin, HS=high‐spin) and FeIIILS(μ‐CN)CoIIILS(μ‐NC)FeIILS linkages could be achieved upon heating and cooling, or alternating laser irradiation at 808 and 532 nm. The electron spin arrangement and charge distribution were simultaneously tuned accompanying bidirectional metal‐to‐metal charge transfer, providing switchable polarity and magnetism in the complex. 相似文献
5.
Dr. Yin‐Shan Meng Prof. Dr. Osamu Sato Prof. Dr. Tao Liu 《Angewandte Chemie (International ed. in English)》2018,57(38):12216-12226
Metal‐to‐metal charge transfer (MMCT) describes electron transfer between metal ions, to generate valence isomers with markedly different electronic configurations. In particular, MMCT changes the spin states of single‐metal sites and the coupling interactions between them, while also changing the symmetry in charge distribution. The result is a drastic change in both magnetic and electric properties of the affected material. Moreover, MMCT causes significant variation in bond length and absorption spectra, and induces unusual thermal expansion and photochromic behavior. Thus, materials demonstrating MMCT in response to external stimuli are excellent candidates for switchable multifunctional devices with synergistic responses. In this Minireview, recent progress in utilizing MMCT units as actuators to tune magnetic, electric, thermal expansion, and photochromic properties in cyanide‐bridged systems is highlighted, and emphasis is given to the remaining challenges and future perspectives in the field. 相似文献
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部花菁染料的多重电荷转移复合物的研究 总被引:1,自引:0,他引:1
自1977年夏在纽约科学院一次会议上Heeger,MacdiarAnd和百)l;英树报告了(CH)。可掺杂到金属态[1]以来,已有许多学者对共轭聚合物的化学掺杂及导电性进行了广泛地研究,用能带模型说明掺杂提高电导的原因.从能带模型可预见只有能隙小,带宽大的共轭聚合物才有可能具有较高的导电性.因为能隙小时离子化电位小,电子亲合力大,易于掺杂.带宽大则掺杂后电子易于迁移问,而与多烯具有相同。电子数的部花育染料的七。x比多烯向更长波长方向位移.例如十六碳八烯的A。。x为410O人而具有同样。电子数的部花育染料BTER的人m。x则为51… 相似文献
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The present paper covers the lipid-free rhodium tetrasulfonato-phthalocyanine (RhTSPc) films prepared on p-Si(111) by using Langmuir-Blodgett technique. Their surface photovoltage spectra were measured. It was found that there is a strong interaction at the interface between the RhTSPc film and p-Si (111) and that the surface photovoltaic effect of the film system is maximum when only one monolayer of RhTSPc molecules coats p-Si(111), which is similar to that of CuTSPc films on p-Si(111) reported previously. These results confirm that only the monolayer of dye molecules being adjacent to the semiconductor surface plays a key role in the light-induced interfacial charge transfer process. 相似文献
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在电子转移半经典模型的基础上,对氟代苯并菲组成的盘状液晶体系的电荷转移反应进行了研究,其反应动力学参数在量子化学B3LYP/6-31G(d,p)水平进行计算.研究中发现在反应物和产物的构型确定后,用线性反应坐标构造的反应途径和过渡态的构型不是唯一的.其原因是反应物和产物确定后,其独立内坐标的选择并不是唯一的.因此在计算电荷转移速率常数时必须考虑到多个过渡态构型才能得到定性正确的结果. 相似文献
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The condensation reaction of 2-cyanomethyl-5-nitropyridine with aromatic aldehydes has been carried out with the aim of preparing 2-azastilbene derivatives having intramolecular charge transfer. The yield of the condensation products can be increased if the reaction is carried out in the medium used for obtaining the starting 2-cyanomethyl-5-nitropyridine without separating or purifying it. The electronic absorption spectra of the compounds show a charge-transfer band, the energy of which increases and the intensity falls with lowering of the electron-donor properties of the substituent in the 4-position. Introduction of the heteroatom into the acceptor part when changing from the stilbene to the 2-azastilbene system is accompanied by a decrease in the energy and increase in the intensity of the charge-transfer electronic transition. 相似文献
11.
电子给受体复合物中电荷转移吸收光谱和溶剂效应 总被引:5,自引:0,他引:5
用MP2/6-31G**方法研究了二氯甲烷溶剂分子与电子给体、受体以及电子给受体复合物间的相互作用,结果表明,二氯甲烷与电子受体和电子给受体复合物间有弱氢键相互作用.利用CIS/6-31++G**方法研究了溶剂与溶质分子间形成氢键对激发态的影响.自然键电荷分析表明,电子给受体复合物的S0→S1跃迁导致一个电子从电子给体转移到受体.结合非平衡溶剂化处理和自洽反应场方法研究了溶剂分子与复合物间形成氢键时的电荷转移吸收光谱.计算表明氢键作用导致复合物的电荷转移吸收光谱蓝移. 相似文献
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Electron transfer is a common characteristic in fullerene complexes and brings about an optoelectronic effect in a polymer-C60 composite and superconductivity in alkali-metal doped C60. This paper reports that the concept of self-trapping of the transferred electron in C60 can explain the main features of photoinduced electron transfer in a polymer-CC60 composite and electron pairing in alkali-metal doped C60. 相似文献
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Sebastian V. Kruppa Cedric Groß Xin Gui Florian Bäppler Björn Kwasigroch Dr. Yu Sun Prof. Dr. Rolf Diller Prof. Dr. Wim Klopper Prof. Dr. Gereon Niedner-Schatteburg Dr. Christoph Riehn Prof. Dr. Werner R. Thiel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(48):11269-11284
The photoexcitation of a triangular silver(I) hydride complex, [Ag3(μ3-H)(μ2-dcpm)3](PF6)2 ([ P ](PF6)2, dcpm=bis(dicyclohexylphosphino)methane), designed with “UV-silent” bis-phosphine ligands, provokes hydride-to-Ag3 single and double electron transfer. The nature of the electronic transitions has been authenticated by absorption and photodissociation spectroscopy in parallel with high-level quantum-chemical computations utilizing the GW method and Bethe–Salpeter equation (GW-BSE). Specific photofragments of mass-selected [ P ]2+ ions testify to charge transfer and competing pathways resulting from the unique [Ag3(μ3-H)]2+ scaffold. This structural motif of [ P ](PF6)2 has been unequivocally verified by 1H NMR spectroscopy in concert with DFT and X-ray diffraction structural analysis, which revealed short equilateral Ag–Ag distances (dAgAg=3.08 Å) within the range of argentophilic interactions. The reduced radical cation [ P ] . + exhibits strong oxophilicity, forming [ P +O2] .+ ,which is a model intermediate for silver oxidation catalysis. 相似文献
16.
Arwa Alrooqi Zahra M. Al-Amshany Laila M. Al-Harbi Tariq A. Altalhi Moamen S. Refat A. M. Hassanien A. A. Atta 《Molecules (Basel, Switzerland)》2022,27(6)
The impact of the charge transfer complex on the dielectric relaxation processes in free poly(methyl methacrylate) (PMMA) polymer sheets was investigated. The frequency dependence of dielectric properties was obtained over the frequency range 0.1 Hz–1 MHz at temperatures ranging between 303 K and 373 K for perylene dye and acceptors (picric acid (PA) and chloranilic acid (CLA)) in an in situ PMMA polymer. The TG/dTG technique was used to investigate the thermal degradation of the synthesized polymeric sheets. Additionally, the kinetic parameters have been assessed using the Coats–Redfern relation. The dielectric relaxation spectroscopy of the synthesized polymeric sheets was analyzed in terms of complex dielectric constant, dielectric loss, electrical modulus, electrical conductivity, and Cole–Cole impedance spectroscopy. α- and β-relaxation processes were detected and discussed. The σ(ω) dispersion curves of the synthesized polymeric sheets show two distinct regions with increasing frequency. The impedance data of the synthesized polymeric sheets can be represented by the equivalent circuit (parallel RC). 相似文献
17.
A series of N-bonded donor-acceptor derivatives of phenothiazine containing phenyl (PHPZ), anisyl (ANPZ), pyridyl (PYPZ), naphthyl (NAPZ), acetylphenyl (APPZ), and cyanophenyl (CPPZ) as an electron acceptor have been synthesized. Their photophysical properties were investigated in solvents of different polarities by absorption and emission techniques. These studies clearly revealed the existence of an intramolecular charge transfer (ICT) excited state in the latter four compounds. The solvent dependent Stokes shift values were analyzed by the modified Lippert-Mataga equation to obtain the excited state dipole moment values. The large excited state dipole moment suggests that the full (or nearly full) electron transfer take place in the A-D systems. In the system of A-D phenothiazine derivatives, the transition dipole moments Mflu were determined mainly by direct interactions between the solvent-equilibrated fluorescence ^1CT state and ground state because of their lack of significant change with increase of the solvent polarity. The electron structure and molecular conformation of phenothiazine derivatives will be significantly changed with the increase of the electron affinity of the N-10 substituent. 相似文献
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Thomas Schwarze Wulfhard Mickler Dr. Carsten Dosche Dr. Roman Flehr Tillmann Klamroth Dr. Hans‐Gerd Löhmannsröben Prof. Dr. Peter Saalfrank Prof. Dr. Hans‐Jürgen Holdt Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1819-1825
Fluoroionophores of fluorophore–spacer–receptor format were prepared for detection of PdCl2 by fluorescence enhancement. The fluorescent probes 1 – 13 consist of a fluorophore group, an alkyl spacer and a dithiomaleonitrile PdCl2 receptor. First, varying the length of the alkylene spacer (compounds 1 – 3 ) revealed a dominant through‐space pathway for oxidative photoinduced electron transfer (PET) in CH2‐bridged dithiomaleonitrile fluoroionophores. Second, fluorescent probes 4 – 9 containing two anthracene or pyrene fragments connected through CH2 bridges to the dithiomaleonitrile unit were synthesized. Modulation of the oxidation potential (EOx) through electron‐withdrawing or ‐donating groups on the anthracene moiety regulates the thermodynamic driving force for oxidative PET (ΔGPET) in bis(anthrylmethylthio)maleonitriles and therefore the fluorescence quantum yields (Φf), too. The new concept was confirmed and transferred to pyrenyl ligands, and fluorescence enhancements (FE) greater than 3.2 in the presence of PdCl2 were achieved by 7 and 8 (FE=5.4 and 5.2). Finally, for comparison, monofluorophore ligands 10 – 13 were synthesized. 相似文献
20.
在具有不同氧化层厚度的p型硅基片上修饰2层磺化酞菁铜分子膜.利用时间分辨表面光电压谱技术,对该膜系的界面电荷转移机制的光电开关特性进行了研究。结果表明,用时间分辨表面光电压谱技术研究界面电荷转移过程具有明显优越性. 相似文献