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1.
Dawei Li Yafei Li David Felipe Tello Yepes Xiamei Zhang Prof. Dr. Yahong Li Prof. Dr. Jin-lei Yao 《化学:亚洲杂志》2021,16(17):2545-2551
A hexanuclear heterometallic cluster of composition [Dy2Co4(L)4(NO3)2(OH)4(C2H5OH)2] ⋅ 2 C2H5OH ( 1 ) was synthesized by employing a Schiff base 2-(((2-hydroxy-3-methoxybenzyl) imino)methyl)-4-methoxyphenol (H2L) as ligand and utilizing Dy(NO3)3 ⋅ 6H2O and Co(NO3)2 ⋅ 6H2O as metal ion sources. X-ray single-crystal diffraction analysis indicated that complex 1 contains a defect tetracubane core and possesses central symmetric structure, with two DyIII ions being in the central body position of the molecule and four CoII ions being arranged at the outer sites. Magnetic studies reveal that complex 1 behaves as single-molecule magnet (SMM) with energy barrier of 27.50 K. To investigate the individual contribution of DyIII and CoII ions to the SMM behavior, another two complexes of formulae [Dy2Zn4(L)4(NO3)2(OH)4] ⋅ 4CH3OH ( 2 ) and [Y2Co4(L)4(NO3)2(OH)4(C2H5OH)2] ⋅ 2 C2H5OH ( 3 ) were prepared. Complexes 1 and 3 are isomorphous. The coordination geometries of DyIII ions in 1 and 2 are different. The DyIII ions are eight-coordinated in 2 and nine-coordinated in 1 . Complex 2 exhibits SMM behavior with energy barrier of 69.67 K, but complex 3 does not display SMM property. These results reveal that the SMM behaviors of 1 and 2 are mainly originated from DyIII ions. It might be the higher symmetry of DyIII ions in 2 that results in the higher energy barrier. 相似文献
2.
Artificial smart materials with switchable multifunctionality are of immense interest owing to their wide application in sensors, displays and memory devices. Lanthanide complexes are promising multifunctional materials integrating optical and magnetic characteristics. However, synergistic manipulation of different physical properties in lanthanide systems is still challenging. Herein we designed and synthesized a mononuclear complex [DyIII(SCN)3(depma)2(4-hpy)2] (1), which incorporates 9-diethylphosphonomethylanthracene (depma) as a photo-active component and 4-hydroxypyridine (4-hpy) as a polar component. This compound shows several unusual features: (a) reversible thermo-responsive phase transition associated with the order–disorder transition of 4-hpy and SCN−, which leads to thermochromic behavior and dielectric anomaly; (b) reversible photo-induced dimerization of anthracene groups, which leads to synergistic switching of luminescence, magnetic and dielectric properties. To our knowledge, compound 1 is the first example of lanthanide complexes that show stimuli-triggered synergistic and reversible switching of luminescence, magnetic and dielectric properties.[DyIII(SCN)3(depma)2(4-hpy)2] (1) shows reversible thermo-induced phase transition associated with thermochromism and dielectric anomaly and photo-induced dimerization with synergistic switching of luminescence, magnetic and dielectric properties. 相似文献
3.
Yingying Wang Zhuangdong Yuan Yunjie Guo Xuxiao Ma Zitong Meng Jingquan Sha Haifeng Zhang 《无机化学与普通化学杂志》2020,646(20):1696-1701
Two dinuclear LnIII-based clusters, namely [Dy2L2(NO3)2(DME)4] ( 1 ) and [Gd2L2(NO3)2(DME)4] ( 2 ) [H2L = (E)-2-((2-hydroxybenzylidene)amino)phenol] were obtained under hydrothermal condition. Two LnIII ions are bridged by two phenolic hydroxyl oxygen atoms, and the distances of them are 3.829 Å (Dy1–Dy1A) and 3.860 Å (Gd1–Gd1A). Two Dy1–O–Dy1A and Gd1–O–Gd1A angles are 109.4° and 109.8°, respectively. Magnetic studies reveal a weak antiferromagnetic interaction between Gd ions in complex 2 , and single-molecule magnet behavior for 1 with Ueff = 49.9 K and τ0 = 1.54 × 10–6 s. 相似文献
4.
Control of the Single‐Molecule Magnet Behavior of Lanthanide‐Diarylethene Photochromic Assemblies by Irradiation with Light
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Dr. Dawid Pinkowicz Min Ren Prof. Li‐Min Zheng Saki Sato Prof. Miki Hasegawa Dr. Masakazu Morimoto Prof. Masahiro Irie Prof. Brian K. Breedlove Dr. Goulven Cosquer Dr. Keiichi Katoh Prof. Masahiro Yamashita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12502-12513
Lanthanide‐based extended coordination frameworks showing photocontrolled single‐molecule magnet (SMM) behavior were prepared by combining highly anisotropic DyIII and HoIII ions with the carboxylato‐functionalized photochromic molecule 1,2‐bis(5‐carboxyl‐2‐methyl‐3‐thienyl)perfluorocyclopentene (H2dae), which acts as a bridging ligand. As a result, two new compounds of the general formula [{LnIII2(dae)3(DMSO)3(MeOH)} ? 10 M eOH]n (M=Dy for 1 a and Ho for 2 ) and two additional pseudo‐polymorphs [{DyIII2(dae)3(DMSO)3(H2O)} ? x MeOH]n ( 1 b ) and [{DyIII2(dae)3(DMSO)3(DMSO)} ? x MeOH]n ( 1 c ) were obtained. All four compounds have 2D coordination‐layer topologies, in which carboxylate‐bridged Ln2 units are linked together by dae2? anions into grid‐like frameworks. All four compounds exhibited a strong reversible photochromic response to UV/Vis light. Moreover, both 1 a and 2 show field‐induced SMM behavior. The slow magnetic relaxation of 1 a is influenced by the photoisomerization reaction leading to the observation of the cross‐effect: photocontrolled SMM behavior. 相似文献
5.
White Light Emissive DyIII Single‐Molecule Magnets Sensitized by Diamagnetic [CoIII(CN)6]3− Linkers
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Dr. Szymon Chorazy Dr. Michał Rams Dr. Koji Nakabayashi Prof. Dr. Barbara Sieklucka Prof. Dr. Shin‐ichi Ohkoshi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(22):7371-7375
The self‐assembly of DyIII–3‐hydroxypyridine (3‐OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido‐bridged {[DyIII(3‐OHpy)2(H2O)4] [CoIII(CN)6]}?H2O ( 1 ) chains. They reveal a single‐molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm?1 (≈385 K), originating from the single‐ion property of eight‐coordinated DyIII of an elongated dodecahedral geometry, which are embedded with diamagnetic [CoIII(CN)6]3? ions into zig‐zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm?1 (≈460 K) at Hdc=1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white DyIII‐based emission realized by energy transfer from CoIII and 3‐OHpy to DyIII. Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto‐luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between DyIII, 3‐OHpy, and [CoIII(CN)6]3?. 相似文献
6.
Lena Scherthan Sebastian F. M. Schmidt Hendrik Auerbach Tim Hochdrffer Juliusz A. Wolny Wenli Bi Jiyong Zhao Michael Y. Hu Tom Toellner E. Ercan Alp Dennis E. Brown Christopher E. Anson Annie K. Powell Volker Schünemann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3482-3487
Time‐domain synchrotron Mössbauer spectroscopy (SMS) based on the Mössbauer effect of 161Dy has been used to investigate the magnetic properties of a DyIII‐based single‐molecule magnet (SMM). The magnetic hyperfine field of [Dy(Cy3PO)2(H2O)5]Br3?2 (Cy3PO)?2 H2O?2 EtOH is with B0=582.3(5) T significantly larger than that of the free‐ion DyIII with a 6H15/2 ground state. This difference is attributed to the influence of the coordinating ligands on the Fermi contact interaction between the s and 4f electrons of the DyIII ion. This study demonstrates that 161Dy SMS is an effective local probe of the influence of the coordinating ligands on the magnetic structure of Dy‐containing compounds. 相似文献
7.
Peipei Cen Dr. Xiangyu Liu Dr. Jesús Ferrando-Soria Yi-Quan Zhang Prof. Gang Xie Prof. Sanping Chen Dr. Emilio Pardo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3884-3892
A family of four mononuclear DyIII β-diketonate complexes with formulas [Dy(tmhd)3(Br2-bpy) ( 1) , [Dy(tmhd)3(Br-bpy)] ( 2 ), [Dy(tmhd)3(dppz)] ( 3 ), and [Dy(tmhd)3(mcdpq)] ( 4 ) (tmhd=2,2,6,6-tetramethyl-3,5-heptanedione, Br2-bpy=5,5′-dibromo-2,2′-bipyridine, Br-bpy=5-bromo-2,2′-bipyridine, dppz=dipyrido [3,2-a:2′,3′-c]phenazine, mcdpq=2-methoxyl-3-cyanodipyrido[3,2-f:2,3′-h]quinoxaline) were prepared by modifying the capping N-donor coligands. DyIII centers in these complexes feature an N2O6 octacoordinate environment with distorted square-antiprismatic D4d symmetry. Magnetic investigations evidenced single-ion magnet behavior in all complexes with energy barriers Ueff of 42.10 ( 1 ), 61.47, ( 2 ), 77.53 ( 3 ), and 2.51 K ( 4 ) in the absence of static field, as well as 206.03 ( 1 ), 224.13 ( 2 ), 247.76 ( 3 ), and 49.70 K ( 4 ) under applied dc field (Hdc=1500 Oe for 1 and 2 ; Hdc=1200 Oe for 3 and 4 ). The different natures of the N-donor ligands induce changes in both the coordination geometry and their intermolecular interactions, which severely impact their magnetic dynamics. The disparities in their magnetic behaviors and the uniaxial anisotropies are also explained and substantiated by theoretical calculations. 相似文献
8.
Dr. F. Pointillart T. Guizouarn B. Lefeuvre Dr. S. Golhen Dr. O. Cador Dr. L. Ouahab 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16929-16934
The rational synthesis of the 2‐{1‐methylpyridine‐N‐oxide‐4,5‐[4,5‐bis(propylthio)tetrathiafulvalenyl]‐1H‐benzimidazol‐2‐yl}pyridine ligand ( L ) is described. It led to the tetranuclear complex [Dy4(tta)12( L )2] ( Dy‐Dy2‐Dy ) after coordination reaction with the precursor Dy(tta)3?2 H2O (tta?=2‐thenoyltrifluoroacetonate). The X‐ray structure of Dy‐Dy2‐Dy can be described as two terminal mononuclear units bridged by a central antiferromagnetically coupled dinuclear complex. The terminal N2O6 and central O8 environments are described as distorted square antiprisms. The ac magnetism measurements revealed a strong out‐of‐phase signal of the magnetic susceptibility with two distinct sets of data. The high‐ and low‐frequency components were attributed to the two terminal mononuclear single‐molecule magnets (SMMs) and the central dinuclear SMM, respectively. A magnetic hysteresis loop was detected at very low temperature. From both structural and magnetic points of view, the tetranuclear SMM Dy‐Dy2‐Dy is a self‐assembly of two known mononuclear SMMs bridged by a known dinuclear SMM. 相似文献
9.
The Building Block [FeIII(pzphen)(CN)4]– and its Lanthanide Complexes: Synthesis,Crystal Structure,and Magnetic Properties
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Jian‐Qing Tao Wen‐Wen Ju Zhou Zhou Li‐Yong Jia Ning‐Ning Chen Yun‐Shan Xue Jun Wang Xing‐Cai Huang 《无机化学与普通化学杂志》2016,642(24):1466-1471
The cyanide building block [FeIII(pzphen)(CN)4]– and its four lanthanide complexes [{FeIII(pzphen)(CN)4}2LnIII(H2O)5(DMF)3] · (NO3) · 2(H2O) · (CH3CN) [Ln = Nd ( 1 ), Sm ( 2 ), DMF = dimethyl formamide] and [{FeIII(pzphen)(CN)4}2LnIII(NO3)(H2O)2(DMF)2](CH3CN) [Ln = Gd ( 3 ), Dy ( 4 )] were synthesized and structurally characterized by single‐crystal X‐ray diffraction. Compounds 1 and 2 are ionic salts with two [FeIII(pzphen)(CN)4]– cations and one LnIII ion, but compounds 3 and 4 are cyano‐bridged FeIII‐LnIII heterometallic 3d‐4f complexes exhibiting a trinuclear structure in the same conditions. Magnetic studies show that compound 3 is antiferromagnetic between the central FeIII and GdIII atoms. Furthermore, the trinuclear cyano‐bridged FeIII2DyIII compound 4 displays no single‐molecular magnets (SMMs) behavior by the alternating current magnetic susceptibility measurements. 相似文献
10.
Two C3‐Symmetric Dy3III Complexes with Triple Di‐μ‐methoxo‐μ‐phenoxo Bridges,Magnetic Ground State,and Single‐Molecule Magnetic Behavior
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Dr. Mikko M. Hänninen Prof. Dr. Antonio J. Mota Dr. Daniel Aravena Prof. Dr. Eliseo Ruiz Prof. Dr. Reijo Sillanpää Dr. Agustín Camón Dr. Marco Evangelisti Prof. Dr. Enrique Colacio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8410-8420
Two series of isostructural C3‐symmetric Ln3 complexes Ln3 ? [BPh4] and Ln3 ? 0.33[Ln(NO3)6] (in which LnIII=Gd and Dy) have been prepared from an amino‐bis(phenol) ligand. X‐ray studies reveal that LnIII ions are connected by one μ2‐phenoxo and two μ3‐methoxo bridges, thus leading to a hexagonal bipyramidal Ln3O5 bridging core in which LnIII ions exhibit a biaugmented trigonal‐prismatic geometry. Magnetic susceptibility studies and ab initio complete active space self‐consistent field (CASSCF) calculations indicate that the magnetic coupling between the DyIII ions, which possess a high axial anisotropy in the ground state, is very weakly antiferromagnetic and mainly dipolar in nature. To reduce the electronic repulsion from the coordinating oxygen atom with the shortest Dy?O distance, the local magnetic moments are oriented almost perpendicular to the Dy3 plane, thus leading to a paramagnetic ground state. CASSCF plus restricted active space state interaction (RASSI) calculations also show that the ground and first excited state of the DyIII ions are separated by approximately 150 and 177 cm?1, for Dy3 ? [BPh4] and Dy3 ? 0.33[Dy(NO3)6], respectively. As expected for these large energy gaps, Dy3 ? [BPh4] and Dy3 ? 0.33[Dy(NO3)6] exhibit, under zero direct‐current (dc) field, thermally activated slow relaxation of the magnetization, which overlap with a quantum tunneling relaxation process. Under an applied Hdc field of 1000 Oe, Dy3 ? [BPh4] exhibits two thermally activated processes with Ueff values of 34.7 and 19.5 cm?1, whereas Dy3 ? 0.33[Dy(NO3)6] shows only one activated process with Ueff=19.5 cm?1. 相似文献
11.
Dr. Yoji Horii Dr. Keiichi Katoh Dr. Kunihisa Sugimoto Dr. Ryo Nakanishi Dr. Brian K. Breedlove Prof. Dr. Masahiro Yamashita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(12):3098-3104
In the research field of single-molecule magnets (SMMs), lanthanoid–lanthanoid interactions, so-called f–f interactions, are known to affect the SMM properties, although their magnitudes are small. In this article, an SMM with very weak f–f interactions is reported, and the effects of the interactions on the SMM properties are discussed. X-ray structural analysis of the DyIII-CdII-phthalocyaninato sextuple-decker complex (Dy2Cd3) reveals that the intramolecular Dy−Dy length in Dy2Cd3 is more than 13 Å, which is longer than the intermolecular Dy−Dy length. Even though the two DyIII ions are far apart, intermolecular ferromagnetic dipole–dipole interactions are observed in Dy2Cd3. From detailed analysis of ac magnetic susceptibilities, quantum tunneling of the magnetization (QTM) in Dy2Cd3 is partially suppressed owing to the existence of very weak Dy−Dy interactions. Our results show that even very weak Dy−Dy interactions act as a dipolar bias, suppressing QTM. 相似文献
12.
《无机化学与普通化学杂志》2018,644(8-9):443-448
A salen‐type Dy2 complex [Dy2(L)(MeOH)2(CH3COO)4] · 2(MeOH) was isolated and magnetically characterized, in which one hexadentate ligand H2L [H2L = N,N‐bis(2‐oxy‐3‐methoxybenzylidene)‐1,2‐phenylenediamine] chelated two DyIII ions, one is located on the apical position of the inner N2O2 site, leaving the outer O2O2 cavity for another DyIII ion. There are two distinct local coordination environments presented as square antiprism (D4d) for Dy1 and biaugmented trigonal prism (C2v) for Dy2. Magnetic measurements reveal that the ferromagnetic interaction between two DyIII ions occurred within low temperature range and accompanied with significant slow magnetic relaxation behavior with energy barriers to the reversal of magnetization Ueff/KB = 40 K under zero dc field. 相似文献
13.
Min Ren Dr. Song‐Song Bao Dr. Norihisa Hoshino Prof. Dr. Tomoyuki Akutagawa Prof. Dr. Bingwu Wang Yu‐Chen Ding Prof. Dr. Shiqiang Wei Prof. Dr. Li‐Min Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(29):9619-9628
A new dysprosium(III) phosphonate dimer {Dy(notpH4)(NO3)(H2O)}2 ? 8 H2O ( 1 ) [notpH6=1,4,7‐triazacyclononane‐1,4,7‐triyl‐tris(methylenephosphonic acid)] that contains two equivalent DyIII ions with a three‐capped trigonal prism environment is reported. Complex 1 can be transformed into {Dy(notpH4)(NO3)(H2O)}2 ( 2 ) in a reversible manner by desorption and absorption of solvent water at ambient temperature. This process is accompanied by a large dielectric response. Magnetic studies reveal that both 1 and 2 show thermally activated magnetization relaxation as expected for single‐molecule magnets. Moreover, the magnetic dynamics of the two compounds can be manipulated by controlling the number of solvent molecules at room temperature. 相似文献
14.
Dr. Juan H. Mecchia Ortiz Daiana Cabrosi Dr. Luca M. Carrella Prof. Dr. Eva Rentschler Prof. Dr. Pablo Alborés 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202201450
We are reporting the synthesis, single-crystal X-ray structure characterization, and magnetic property investigations of the pivalate butterfly {CrIII2LnIII2} complexes with Ln= Gd and Dy and the isostructural Y(III) sample. We found an anti-ferromagnetic Cr(III)-Ln(III) exchange interaction, which, as previously observed in related Cr(III)/Ln(III) systems, plays a key role in suppressing quantum tunnelling of magnetization and enhances the SMM performance in the Dy(III) complex. In fact, a pure Orbach relaxation mechanism, with absence of QT regime, is observed with a thermal barrier of 50 cm−1, leading to magnetization hysteresis opening, measured with a commercial magnetometer, up to 3.6 K with a coercive field of 2.9 T. Analysis of SMM behaviour in literature-known butterfly {CrIII2DyIII2} complexes, reveals the existence of a magneto-structural correlation between Ueff, the thermal barrier size, and the mean Cr−Dy bond distances. Moreover, a clear correlation is found for the thermal barrier magnitude and the maximum temperature hysteresis opening and coercive field. 相似文献
15.
Dr. Ritwik Modak Dr. Yeasin Sikdar Prof. Carlos J. Gómez-García Dr. Samia Benmansour Dr. Sudipta Chatterjee Dr. Sanchita Goswami 《化学:亚洲杂志》2021,16(6):666-677
The combination of Co(III) and Dy(III) with a compartmental Schiff base ligand (H3L=3-[(2-Hydroxy-3-methoxy-benzylidene)-amino]-propane-1,2-diol), presenting three different coordinating pockets, has allowed the synthesis of two novel Co(III)−Dy(III) complexes: [Co2Dy(HL)4]NO3 ⋅ 2CH3CN ( 1 ), a rare example of trinuclear linear CoIII2DyIII complex (and the first with slow relaxation of magnetization in absence of a DC field) and [Co2Dy2(μ3−OH)2(HL)2(OAc)6] ⋅ 4.6H2O ( 2 ), the first tetranuclear CoIII2DyIII2 cluster with a rhomb-like structure where the Co(III) ions are connected along the short diagonal of the rhomb. 1 presents two different relaxation processes: a fast relaxation dominated by Quantum tunnelling (QT) and a slow relaxation with an energy barrier of 40 K. 2 shows two close relaxation processes without applied DC fields that follow QT and Orbach mechanisms whereas for HDC=500 Oe, the QT is cancelled and a direct term appears. Here we present the synthesis, X-ray structure and magnetic characterization of these two Co(III)−Dy(III) single-ion/molecule magnets. 相似文献
16.
Angelos B. Canaj Sourav Dey Emma Regincs Martí Claire Wilson Gopalan Rajaraman Mark Murrie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(40):14284-14289
Following a novel synthetic strategy where the strong uniaxial ligand field generated by the Ph3SiO? (Ph3SiO?=anion of triphenylsilanol) and the 2,4‐di‐tBu‐PhO? (2,4‐di‐tBu‐PhO?=anion of 2,4‐di‐tertbutylphenol) ligands combined with the weak equatorial field of the ligand LN6 , leads to [DyIII(LN6)(2,4‐di‐tBu‐PhO)2](PF6) ( 1 ), [DyIII(LN6)(Ph3SiO)2](PF6) ( 2 ) and [DyIII(LN6)(Ph3SiO)2](BPh4) ( 3 ) hexagonal bipyramidal dysprosium(III) single‐molecule magnets (SMMs) with high anisotropy barriers of Ueff=973 K for 1 , Ueff=1080 K for 2 and Ueff=1124 K for 3 under zero applied dc field. Ab initio calculations predict that the dominant magnetization reversal barrier of these complexes expands up to the 3rd Kramers doublet, thus revealing for the first time the exceptional uniaxial magnetic anisotropy that even the six equatorial donor atoms fail to negate, opening up the possibility to other higher‐order symmetry SMMs. 相似文献
17.
Two new Zn2Dy2 complexes were constructed from Zn (II) salen‐type Schiff base complex fragment and 2,6‐pyridinedimethanol (H2pdm) or its Br‐substituted analogue (4‐bromopyridine‐2,6‐diyl)dimethanol (H2Brpdm); their molecular formulas are [Zn2Dy2(L)2(pdm)2(MeOH)2](ClO4)2 [ 1 , H2L = N, N′‐ bis(3‐methoxysalicylidene)‐1,3‐diaminopropane] and [Zn2Dy2(L)2(Brpdm)2(MeOH)2](ClO4)2 [ 2 ], the Dy (III) ions of which have a NO7 triangular dodecahedral coordination sphere. The two complexes show not only ferromagnetic interaction but also field‐induced single‐molecule magnet (SMM) behavior, which are rare Dy (III)‐containing cluster complexes with the NO7 triangular dodecahedral coordination sphere that can show good magnetic relaxation. The energy barrier value of complex 2 is higher than those of complex 1 and the Dy (III) complexes with the DyNO7 triangular dodecahedral coordination configuration reported in the literature. 相似文献
18.
Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis,Crystal Structures,and Magnetic Properties
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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
19.
Tian Han Dr. Wei Shi Zheng Niu Bo Na Prof. Dr. Peng Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):994-1001
The combination of the anisotropic DyIII ion and organic radicals as spin carriers results in discrete and one‐dimensional lanthanide–radical magnetic materials, namely, [Dy(hfac)3(NITThienPh)2] ( 1 ) and [Dy2(hfac)6(NITThienPh)2]n ( 2 ; hfac=hexafluoroacetylacetonate, NITThienPh=2‐(5‐phenyl‐2‐thienyl)‐4,4,5,5‐tetramethyl‐imidazoline‐1‐oxyl‐3‐oxide). Linking monomeric 1 with the DyIII ion leads to the formation of polymeric 2 , and the transformation between them is chemically controllable and reversible. The characterization of both static and dynamic magnetic properties shows that the dominant intrachain exchange interaction is important to observe magnetic bistability in 2 rather than that in 1 . Monomeric 1 exhibits paramagnetic behavior, whereas polymeric 2 shows the unusual coexistence of superparamagnetic and two‐step field‐induced metamagnetic behaviors. The antiferromagnetic ground state of 2 does not prevent the dynamic relaxation of the magnetization with the finite‐sized effect in the lanthanide–radical system. Energy barriers to thermally activated relaxation for 2 are 53 and 98 K in the low‐ and high‐temperature regimes, respectively. A hysteresis loop is observed with the coercive field of 99 Oe at 2 K. 相似文献
20.
Lena Scherthan Rouven F. Pfleger Hendrik Auerbach Tim Hochdrffer Juliusz A. Wolny Wenli Bi Jiyong Zhao Michael Y. Hu E. Ercan Alp Christopher E. Anson Rolf Diller Annie K. Powell Volker Schünemann 《Angewandte Chemie (International ed. in English)》2020,59(23):8818-8822
Synchrotron‐based nuclear resonance vibrational spectroscopy (NRVS) using the Mössbauer isotope 161Dy has been employed for the first time to study the vibrational properties of a single‐molecule magnet (SMM) incorporating DyIII, namely [Dy(Cy3PO)2(H2O)5]Br3?2 (Cy3PO)?2 H2O ?2 EtOH. The experimental partial phonon density of states (pDOS), which includes all vibrational modes involving a displacement of the DyIII ion, was reproduced by means of simulations using density functional theory (DFT), enabling the assignment of all intramolecular vibrational modes. This study proves that 161Dy NRVS is a powerful experimental tool with significant potential to help to clarify the role of phonons in SMMs. 相似文献