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1.
Wen Wen Yin‐Shan Meng Cheng‐Qi Jiao Qiang Liu Hai‐Lang Zhu Ya‐Ming Li Hiroki Oshio Tao Liu 《Angewandte Chemie (International ed. in English)》2020,59(38):16393-16397
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
2.
Hui-Ying Sun Dr. Yin-Shan Meng Dr. Liang Zhao Nian-Tao Yao Pan-Dong Mao Qiang Liu Fei-Fei Yan Prof. Hiroki Oshio Prof. Tao Liu 《Angewandte Chemie (International ed. in English)》2023,62(28):e202302815
Colossal and anisotropic thermal expansion is a key function for microscale or nanoscale actuators in material science. Herein, we present a hexanuclear compound of [(Tp*)FeIII(CN)3]4[FeII(Ppmp)]2⋅2 CH3OH ( 1 , Tp*=hydrotris(3,5-dimethyl-pyrazol-1-yl)borate and Ppmp=2-[3-(2′-pyridyl)pyrazol-1-ylmethyl]pyridine), which has a rhombic core structure abbreviated as {FeIII2FeII2}. Magnetic susceptibility measurements and single-crystal X-ray diffraction analyses revealed that 1 underwent thermally-induced spin transition with the thermal hysteresis. The FeII site in 1 behaved as a spin crossover (SCO) unit, and significant deformation of its octahedron was observed during the spin transition process. Moreover, the distortion of the FeII centers actuated anisotropic deformation of the rhombic {FeIII2FeII2} core, which was spread over the whole crystal through the subsequent molecular rearrangements, leading to the colossal anisotropic thermal expansion. Our results provide a rational strategy for realizing the colossal anisotropic thermal expansion and shape memory effects by tuning the magnetic bistability. 相似文献
3.
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
4.
Dr. Min‐Xia Yao Qi Zheng Kang Qian Prof. Dr. You Song Prof. Dr. Song Gao Prof. Dr. Jing‐Lin Zuo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):294-303
By using the node‐and‐spacer approach in suitable solvents, four new heterotrimetallic 1D chain‐like compounds (that is, containing 3d–3d′–4f metal ions), {[Ni(L)Ln(NO3)2(H2O)Fe(Tp*)(CN)3] ? 2 CH3CN ? CH3OH}n (H2L=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, Tp*=hydridotris(3,5‐dimethylpyrazol‐1‐yl)borate; Ln=Gd ( 1 ), Dy ( 2 ), Tb ( 3 ), Nd ( 4 )), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide‐ and phenolate‐bridged heterotrimetallic chain, with a {? Fe? C?N? Ni(? O? Ln)? N?C? }n repeat unit. Within these chains, each [(Tp*)Fe(CN)3]? entity binds to the NiII ion of the [Ni(L)Ln(NO3)2(H2O)]+ motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO3)2(H2O)]+ unit is linked to two [(Tp*)Fe(CN)3]? ions through the NiII ion in a trans mode. In the [Ni(L)Ln(NO3)2(H2O)]+ unit, the NiII and LnIII ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1 – 4 are rare examples of 1D cyanide‐ and phenolate‐bridged 3d–3d′–4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring FeIII and NiII ions through a cyanide bridge and between neighboring NiII and LnIII (except for NdIII) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single‐chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d–4f heterotrimetallic single‐chain magnets. 相似文献
5.
Zhao‐Yang Li Jing‐Wei Dai Marko Damjanovi Takuya Shiga Jin‐Hua Wang Jia Zhao Hiroki Oshio Masahiro Yamashita Xian‐He Bu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4383-4388
We report three self‐assembled iron complexes that comprised an anti‐parallel open form (o‐ L anti), a parallel open form (o‐ L syn), and a closed form (c‐ L ) of diarylethene conformers. Under kinetic control, FeII2(o‐ L anti)3 was isolated, which exhibited a dinuclear structure with diamagnetic properties. Under light‐irradiation control, FeII2(c‐ L )3 was prepared and exhibited paramagnetism and spin‐crossover behaviour. Under thermodynamic control and in the presence of indispensable [FeIII(Tp*)(CN)3]?, FeII2(o‐ L anti)3 and FeII2(c‐ L )3 transformed into tetranuclear FeIII2FeII2(o‐ L syn)2, which exhibited complete spin‐crossover behaviour at T1/2=353 K. 相似文献
6.
Mitsumoto K Oshiro E Nishikawa H Shiga T Yamamura Y Saito K Oshio H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(35):9612-9618
Cyanide‐bridged metal complexes of [Fe8M6(μ‐CN)14(CN)10 (tp)8(HL)10(CH3CN)2][PF6]4?n CH3CN?m H2O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1H‐pyrazole), tp?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P21/n. They have tetradecanuclear cores composed of eight low‐spin (LS) FeIII and six high‐spin (HS) MII ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐FeII)3(LS‐FeIII)5(HS‐CoII)3(LS‐CoIII)3] and the [(LS‐FeIII)8(HS‐CoII)6] states. 相似文献
7.
Szymon Chorazy Tomasz Charytanowicz Dawid Pinkowicz Junhao Wang Koji Nakabayashi Stephen Klimke Franz Renz Shin‐ichi Ohkoshi Barbara Sieklucka 《Angewandte Chemie (International ed. in English)》2020,59(36):15741-15749
A two‐step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3‐CNpy)2][Re(CN)8]}?H2O ( 1 ) (3‐CNpy=3‐cyanopyridine) assembly consisting of cyanido‐bridged FeII‐ReV square grid sheets bonded by Cs+ ions. The presence of two non‐equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non‐covalent interlayer interactions involving Cs+, [ReV(CN)8]3? ions, and 3‐CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin‐transition phenomenon could be tuned by an external pressure giving the room‐temperature range of SCO, as well as by visible‐light irradiation, inducing an efficient recovery of the high‐spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect. 相似文献
8.
Dr. Siddhartha De Dr. Alexandrine Flambard Buqin Xu Lise-Marie Chamoreau Geoffrey Gontard Dr. Laurent Lisnard Dr. Yanling Li Dr. Marie-Laure Boillot Prof. Rodrigue Lescouëzec 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(50):e202200783
The cyanidocobaltate of formula fac-PPh4[CoIII(Me2Tp)(CN)3] ⋅ CH3CN ( 1 ) has been used as a metalloligand to prepare polynuclear magnetic complexes (Me2Tp=hydrotris(3,5-dimethylpyrazol-1-yl)borate). The association of 1 with in situ prepared [FeII(bik)2(MeCN)2](OTf)2 (bik=bis(1-methylimidazol-2-yl)ketone) leads to a molecular square of formula {[CoIII{(Me2Tp)}(CN)3]2[FeII(bik)2]2}(OTf)2 ⋅ 4MeCN ⋅ 2H2O ( 2 ), whereas the self-assembly of 1 with preformed cluster [CoII2(OH2)(piv)4(Hpiv)4] in MeCN leads to the two-dimensional network of formula {[CoII2(piv)3]2[CoIII(Me2Tp)(CN)3]2 ⋅ 2CH3CN}∞ ( 3 ). These compounds were structurally characterized via single crystal X-ray analysis and their spectroscopic (FTIR, UV-Vis and 59Co NMR) properties and magnetic behaviours were also investigated. Bulk magnetic susceptibility measurements reveal that 1 is diamagnetic and 3 is paramagnetic throughout the explored temperature range, whereas 2 exhibits sharp spin transition centered at ca. 292 K. Compound 2 also exhibits photomagnetic effects at low temperature, selective light irradiations allowing to promote reversibly and repeatedly low-spin⇔high-spin conversion. Besides, the diamagnetic nature of the Co(III) building block allows us studying these compounds by means of 59Co NMR spectroscopy. Herein, a 59Co chemical shift has been used as a magnetic probe to corroborate experimental magnetic data obtained from bulk magnetic susceptibility measurements. An influence of the magnetic state of the neighbouring atoms is observed on the 59Co NMR signals. Moreover, for the very first time, 59Co NMR technique has been successfully introduced to investigate molecular materials with distinct magnetic properties. 相似文献
9.
《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
10.
Takuya Shiga Ryo Saiki Lisa Akiyama Reiji Kumai Dominik Natke Franz Renz Jamie M. Cameron Graham N. Newton Hiroki Oshio 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(17):5714-5718
A mononuclear FeII complex, prepared with a Brønsted diacid ligand, H2L (H2L=2‐[5‐phenyl‐1H‐pyrazole‐3‐yl] 6‐benzimidazole pyridine), shows switchable physical properties and was isolated in five different electronic states. The spin crossover (SCO) complex, [FeII(H2L)2](BF4)2 ( 1A ), exhibits abrupt spin transition at T1/2=258 K, and treatment with base yields a deprotonated analogue [FeII(HL)2] ( 1B ), which shows gradual SCO above 350 K. A range of FeIII analogues were also characterized. [FeIII(HL)(H2L)](BF4)Cl ( 1C ) has an S=5/2 spin state, while the deprotonated complexes [FeIII(L)(HL)], ( 1D ), and (TEA)[FeIII(L)2], ( 1E ) exist in the low‐spin S=1/2 state. The electronic properties of the five complexes were fully characterized and we demonstrate in situ switching between multiple states in both solution and the solid‐state. The versatility of this simple mononuclear system illustrates how proton donor/acceptor ligands can vastly increase the range of accessible states in switchable molecular devices. 相似文献
11.
Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis,Crystal Structures,and Magnetic Properties 下载免费PDF全文
Dr. Maria‐Gabriela Alexandru Dr. Diana Visinescu Prof. Marius Andruh Dr. Nadia Marino Dr. Donatella Armentano Dr. Joan Cano Prof. Francesc Lloret Prof. Miguel Julve 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5429-5446
The use of the [FeIII(AA)(CN)4]? complex anion as metalloligand towards the preformed [CuII(valpn)LnIII]3+ or [NiII(valpn)LnIII]3+ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H2valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[CuII(valpn)LnIII(H2O)3(μ‐NC)2FeIII(phen)(CN)2 {(μ‐NC)FeIII(phen)(CN)3}]NO3 ? 7 H2O}n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [CuII(valpn)LaIII(OH2)3(O2NO)(μ‐NC)FeIII(phen)(CN)3] ? NO3 ? H2O ? CH3CN ( 4 ) were obtained with the [CuII(valpn)LnIII]3+ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[NiII(valpn)LnIII(ONO2)2(H2O)(μ‐NC)3FeIII(bipy)(CN)] ? 2 H2O ? 2 CH3CN}n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [NiII(valpn)LnIII]3+ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [CuII(valpn)LaIII(OH2)3(O2NO)(μ‐NC)FeIII(phen)(CN)3]+, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {FeIII(bipy)(CN)4} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {NiII(valpn)LnIII} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the CuII?LnIII ( 1 – 3 ) and NiII?LnIII ( 5 – 7 ) units, as well as through the single cyanide bridge between the FeIII and either NiII ( 5 – 7 ) or CuII ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor (τo) and energy barrier (Ea) through the Arrhenius equation being 2.0×10?12 s and 29.1 cm?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (NiII–DyIII) and single cyanide (FeIII–NiII) pathways are masked by the depopulation of the Stark levels of the DyIII ion, this feature most likely accounting for the continuous decrease of χM T upon cooling observed for this last compound. 相似文献
12.
Dr. Kuirun Zhang Dr. Soonchul Kang Dr. Zi‐shuo Yao Kazusa Nakamura Dr. Takashi Yamamoto Prof. Dr. Yasuaki Einaga Nobuaki Azuma Dr. Yuji Miyazaki Prof. Dr. Motohiro Nakano Dr. Shinji Kanegawa Prof. Dr. Osamu Sato 《Angewandte Chemie (International ed. in English)》2016,55(20):6047-6050
Heterometallic Prussian blue analogues are known to exhibit thermally induced charge transfer, resulting in switching of optical and magnetic properties. However, charge‐transfer phase transitions have not been reported for the simplest FeFe cyanide‐bridged systems. A mixed‐valence FeII/FeIII cyanide‐bridged coordination polymer, {[Fe(Tp)(CN)3]2Fe(bpe)?5 H2O}n, which demonstrates a thermally induced charge‐transfer phase transition, is described. As a result of the charge transfer during this phase transition, the high‐spin state of the whole system does not change to a low‐spin state. This result is in contrast to FeCo cyanide‐bridged systems that exhibit charge‐transfer‐induced spin transitions. 相似文献
13.
Li-Zheng Cai Wei Zhang Zhao-Xia Zhu Jing Ru 《Journal of Coordination Chemistry》2019,72(5-7):1097-1107
Three FeIII2LnIII2 tetranuclear heterometallic clusters, [H4LGd(H2O)Tp*Fe(CN)3]2·8H2O·2MeOH (1) and [H4LLn(MeOH)Tp*Fe(CN)3]2·6MeOH·2MeCN (Ln?=?Tb and Dy for 2 and 3, respectively, H6L = N,N′-(2,6-pyridine-dicarboxyl)-disalicylhydrazide, Tp* = hydridotris(3,5dimethylpyrazol-1-yl)-borate), were synthesized by use of the [(Tp*)Fe(CN)3]? unit as a metalloligand toward LnCl3 and H6L species. Structural analyses reveal that FeIII and LnIII ions in all complexes are connected to each other by one cyanide to form a heterobinuclear unit of [Ln(H4L)][(Tp*)Fe(CN)3], which is dimerized through Ln–N–C?=?O–Ln interaction. Magnetic susceptibility measurements show weak antiferromagnetic interactions between cyano-bridged FeIII and GdIII ions and amide-bridged GdIII ions are operative. Complex 1 displays the magnetocaloric effect with ?ΔSmmax = 12.70 J·kg?1·K?1 at 4.0 K for ΔH?=?7 T. No single-molecule magnetic properties are observed for 2 or 3 down to 1.8 K. 相似文献
14.
Jun‐Fang Guo Dr. Xiu‐Teng Wang Dr. Bing‐Wu Wang Dr. Guan‐Cheng Xu Dr. Song Gao Prof. Lap Szeto Wing‐Tak Wong Prof. Wai‐Yeung Wong Prof. Tai‐Chu Lau Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(11):3524-3535
Four cyano‐bridged 1D bimetallic polymers have been prepared by using the paramagnetic building block trans‐[Ru(acac)2(CN)2]? (Hacac=acetylacetone): {[{Ni(tren)}{Ru(acac)2(CN)2}][ClO4]?CH3OH}n ( 1 ) (tren=tris(2‐aminoethyl)amine), {[{Ni(cyclen)}{Ru(acac)2(CN)2}][ClO4]? CH3OH}n ( 2 ) (cyclen=1,4,7,10‐tetraazacyclododecane), {[{Fe(salen)}{Ru(acac)2(CN)2}]}n ( 3 ) (salen2?=N,N′‐bis(salicylidene)‐o‐ethyldiamine dianion) and [{Mn(5,5′‐Me2salen)}2{Ru(acac)2(CN)2}][Ru(acac)2(CN)2]? 2 CH3OH ( 4 ) (5,5′‐Me2salen=N,N′‐bis(5,5′‐dimethylsalicylidene)‐o‐ethylenediimine). Compounds 1 and 2 are 1D, zigzagged NiRu chains that exhibit ferromagnetic coupling between NiII and RuIII ions through cyano bridges with J=+1.92 cm?1, z J′=?1.37 cm?1, g=2.20 for 1 and J=+0.85 cm?1, z J′=?0.16 cm?1, g=2.24 for 2 . Compound 3 has a 1D linear chain structure that exhibits intrachain ferromagnetic coupling (J=+0.62 cm?1, z J′=?0.09 cm?1, g=2.08), but antiferromagnetic coupling occurs between FeRu chains, leading to metamagnetic behavior with TN=2.6 K. In compound 4 , two MnIII ions are coordinated to trans‐[Ru(acac)2(CN)2]? to form trinuclear Mn2Ru units, which are linked together by π–π stacking and weak Mn???O* interactions to form a 1D chain. Compound 4 shows slow magnetic relaxation below 3.0 K with ?=0.25, characteristic of superparamagnetic behavior. The MnIII???RuIII coupling constant (through cyano bridges) and the MnIII???MnIII coupling constant (between the trimers) are +0.87 and +0.24 cm?1, respectively. Compound 4 is a novel single‐chain magnet built from Mn2Ru trimers through noncovalent interactions. Density functional theory (DFT) combined with the broken symmetry state method was used to calculate the molecular magnetic orbitals and the magnetic exchange interactions between RuIII and M (M=NiII, FeIII, and MnIII) ions. To explain the somewhat unexpected ferromagnetic coupling between low‐spin RuIII and high‐spin FeIII and MnIII ions in compounds 3 and 4 , respectively, it is proposed that apart from the relative symmetries, the relative energies of the magnetic orbitals may also be important in determining the overall magnetic coupling in these bimetallic assemblies. 相似文献
15.
Dr. Szymon Chorazy Tomasz Charytanowicz Dr. Dawid Pinkowicz Junhao Wang Dr. Koji Nakabayashi Stephen Klimke Prof. Dr. Franz Renz Prof. Dr. Shin-ichi Ohkoshi Prof. Dr. Barbara Sieklucka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15871-15879
A two-step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3-CNpy)2][Re(CN)8]}⋅H2O ( 1 ) (3-CNpy=3-cyanopyridine) assembly consisting of cyanido-bridged FeII-ReV square grid sheets bonded by Cs+ ions. The presence of two non-equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non-covalent interlayer interactions involving Cs+, [ReV(CN)8]3− ions, and 3-CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin-transition phenomenon could be tuned by an external pressure giving the room-temperature range of SCO, as well as by visible-light irradiation, inducing an efficient recovery of the high-spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect. 相似文献
16.
High Sensitive Microsensor Based on Organic‐Inorganic Composite for Two‐Dimensional Mapping of H2O2 by SECM 下载免费PDF全文
Danielle Diniz Justino Isabel Lourenço Torres Rita de Cássia Silva Luz Flavio Santos Damos 《Electroanalysis》2015,27(5):1202-1209
The present work describes the development of a selective, sensitive and stable sensing microsensor for scanning electrochemical microscopy (SECM) to measure H2O2 during electrochemical reduction of oxygen. The microsensor is based on graphene and Poly(3,4‐ethylenedioxythiophene) composite as support to iron (III) hexacyanoferrate (II) (PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor). The electrochemical properties of the PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor were investigated by cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). The PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor showed an excellent electrocatalytic activity toward hydrogen peroxide (H2O2) reduction with a diminution of the overpotential of about 500 mV in comparison to the process at a bare gold microelectrode. The microsensor presented excellent performance for two dimensional mapping of H2O2 by SECM in 0.1 mol L?1 phosphate buffer solution (pH 7.0). Under optimized conditions, a linear response range from 1 up to 1000 µmol L?1 was obtained with a sensitivity of 0.08 nA L µmol?1 and limit of detection of 0.5 µmol L?1. 相似文献
17.
Prof. Dr. Yusuke Yamada Masaki Yoneda Prof. Dr. Shunichi Fukuzumi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(35):11733-11741
A robust one‐compartment H2O2 fuel cell, which operates without membranes at room temperature, has been constructed by using a series of polynuclear cyanide complexes that contain Fe, Co, Mn, and Cr as cathodes, in sharp contrast to conventional H2 and MeOH fuel cells, which require membranes and high temperatures. A high open‐circuit potential of 0.68 V was achieved by using Fe3[{CoIII(CN)6}2] on a carbon cloth as the cathode and a Ni mesh as the anode of a H2O2 fuel cell by using an aqueous solution of H2O2 (0.30 M , pH 3) with a maximum power density of 0.45 mW cm?2. The open‐circuit potential and maximum power density of the H2O2 fuel cell were further increased to 0.78 V and 1.2 mW cm?2, respectively, by operation under these conditions at pH 1. No catalytic activity of Co3[{CoIII(CN)6}2] and Co3[{FeIII(CN)6}2] towards H2O2 reduction suggests that the N‐bound Fe ions are active species for H2O2 reduction. H2O2 fuel cells that used Fe3[{MnIII(CN)6}2] and Fe3[{CrIII(CN)6}2] as the cathode exhibited lower performance compared with that using Fe3[{CoIII(CN)6}2] as a cathode, because ligand isomerization of Fe3[{MIII(CN)6}2] into (FeM2)[{FeII(CN)6}2] (M=Cr or Mn) occurred to form inactive Fe? C bonds under ambient conditions, whereas no ligand isomerization of Fe3[{CoIII(CN)6}2] occurred under the same reaction conditions. The importance of stable Fe2+? N bonds was further indicated by the high performance of the H2O2 fuel cells with Fe3[{IrIII(CN)6}2] and Fe3[{RhIII(CN)6}2], which also contained stable Fe2+? N bonds. The stable Fe2+? N bonds in Fe3[{CoIII(CN)6}2], which lead to high activity for the electrocatalytic reduction of H2O2, allow Fe3[{CoIII(CN)6}2] to act as a superior cathode in one‐compartment H2O2 fuel cells. 相似文献
18.
Alexandre Abhervé Samuel Ma?as-Valero Miguel Clemente-León Eugenio Coronado 《Chemical science》2015,6(8):4665-4673
The syntheses, structures and magnetic properties of the coordination compounds of formula [FeIII(acac2-trien)][MnIICrIII(Cl2 An)3]·(CH3CN)2 (1), [FeIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (2) and [GaIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (3) are reported. They exhibit a 2D anionic network formed by Mn(ii) and Cr(iii) ions linked through anilate ligands, while the [FeIII(acac2-trien)]+ or [GaIII(acac2-trien)]+ charge-compensating cations are placed inside the hexagonal channels of the 2D network, instead of being inserted in the interlamellar spacing. Thus, these crystals are formed by hybrid layers assembled through van der Waals interactions. The magnetic properties indicate that these compounds behave as magnets exhibiting a long-range ferrimagnetic ordering at ca. 11 K, while the inserted Fe(iii) cations remain in the high-spin state. As for graphene, these layered materials can be exfoliated in atomically-thin layers with heights down to 2 nm by using the well-known Scotch tape method. Hence, this micromechanical procedure provides a suitable way to isolate ultrathin layers of this kind of graphene related magnetic materials. Interestingly, this method can also be successfully used to exfoliate the 2D anilate-based compound [FeIII(sal2-trien)][MnIICrIII(Cl2An)3]·solv (4), which exhibits the typical alternated cation/anion layered structure. This result shows that the micromechanical exfoliation method, which has been extensively used for exfoliating van der Waals layered solids, can also be useful for exfoliating layered coordination compounds, even when they are formed by ionic components. 相似文献
19.
《Journal of Coordination Chemistry》2012,65(22):3907-3913
Polycrystalline Co0.75Ni0.75[Fe(CN)6]?·?XH2O was prepared by coprecipitation. The coprecipitated powder was annealed in vacuum at 80°C, 100°C, and 130°C. Variation of microstructural and magnetic properties with different annealed temperatures was studied by Fourier-transform infrared, X-ray diffraction, and magnetization measurements. The differences in magnetic phase transition temperature, coercivity, remanence, and effective magnetization were studied in detail. The magnetic contribution mainly results from FeIII–CN–CoII/NiII and FeIII–NC–CoII/NiII because FeII–CN–CoIII/NiII carries no net spin. After annealing at 130°C, the microstructures FeIII–CN–CoII/NiII and FeIII–NC–CoII/NiII convert to FeII–CN–CoIII/NiII. Differences in magnetic properties may be attributed to heat-induced microstructural changes. 相似文献
20.
Dr. Ioannis Liratzis Dr. Stephan Walleck Dr. Jan Oldengott Anja Stammler Dr. Hartmut Bögge Dr. Eckhard Bill Prof. Dr. Thorsten Glaser 《欧洲无机化学杂志》2023,26(5):e202200650
The ligand H6ioan has been used to synthesize the three dinuclear complexes [(ioan)MnIITiIV], [(ioan)FeIITiIV], and [(ioan)FeIIITiIV]+. The face-sharing bridging mode of the three phenolates provides short M-TiIV distances of ≈3.0 Å. Mössbauer spectra of [(ioan)FeIIITiIV]+ show a magnetically split six-line spectrum at 3 K in zero magnetic field demonstrating a slow magnetic relaxation. Magnetic measurements provide a zero-field splitting of |D|=5 cm−1 in [(ioan)FeIITiIV]. EPR spectroscopy demonstrates sizable zero-field splittings of the S=5/2 spin systems of [(ioan)MnIITiIV] (D=0.246 cm−1) and [(ioan)FeIIITiIV]+ (D<−1 cm−1) that can be related to enforced covalency of the M-Oph bonds. [(ioan)FeIIITiIV]+ exhibits a reversible reduction at −0.26 V vs. Fc+/Fc demonstrating the facile accessibility of FeIII and FeII. In contrast to an irreversible oxidation in [(ioan)NiIITiIV] at 0.78 V vs. Fc+/Fc, the reversible oxidation at 0.25 V vs. Fc+/Fc in [(ioan)MnIITiIV] indicates even the access of MnIII. These results indicate that pentanuclear complexes [(ioan)FeM1M2M1Fe(ioan)]n+ are meaningful targets to access electron delocalization in mixed-valence systems over five ions due to the facile accessibility of both FeII and FeIII in the terminal positions. This study provides important local spin-Hamiltonian and Mössbauer parameters that will be essential for the understanding of the potentially complicated electronic structure in the anticipated pentanuclear complexes. 相似文献