Co-reporter:Wen Zhang, Heng-Yun Ye, Robert Graf, Hans W. Spiess, Ye-Feng Yao, Run-Qiang Zhu, and Ren-Gen Xiong
Journal of the American Chemical Society April 10, 2013 Volume 135(Issue 14) pp:5230-5233
Publication Date(Web):March 21, 2013
DOI:10.1021/ja3110335
The inclusion compound [(CH3)2NH2]2[KCo(CN)6] exhibits a marked temperature-dependent dielectric constant and can be considered as a model of tunable and switchable dielectric materials. Crystal structure and solid-state NMR studies reveal a switchable property between low and high dielectric states around 245 K. This originates from an order–disorder phase transition of the system, changing the dynamics of the polar dimethylammonium (DMA) cation. Furthermore, the tuning of the dielectric constant at temperatures below the phase transition point is related to increasing angular pretransitional fluctuations of the dipole moment of DMA.
Co-reporter:Xiang-Bin Han, Pan Hu, Chao Shi, Wen Zhang
Journal of Molecular Structure 2017 Volume 1127() pp:372-376
Publication Date(Web):5 January 2017
DOI:10.1016/j.molstruc.2016.07.113
•A 1,4-diazabicyclo[2.2.2]octane based organic salt was synthesized.•Two reversible phase transitions occur due to local structural changes of the water molecule, the cation and the PF6− anion.•Dielectric transitions are triggered in the crystal.1,4-Diazabicyclo[2.2.2]octane (dabco) based organic crystal [(Hdabco)(H2O)](PF6) (1) was synthesized and characterized. Its structure is featured by wavy-like one-dimensional supramolecular hydrogen bond chains built from the [(Hdabco)(H2O)] units from end to end. Compound 1 undergoes two reversible phase transitions at 226/268 K and 178/181 K, respectively. The disorder-order transition of water molecule in the hydrogen bond chain induces the phase transition at 226 K while the twisting of the [Hdabco]+ cation and displacements of the PF6− anion and H2O molecules trigger the phase transition at 178 K. Dielectric transitions are thus triggered in the crystal.Organic crystal 1,4-diazabicyclo[2.2.2]octane hydrohexafluorophosphate monohydrate undergoes two reversible phase transitions at 226/268 K and 178/181 K, due to the disorder-order transition of water molecule in the hydrogen bond chain and the twisting of the [Hdabco]+ cation and displacements of the PF6− anion and H2O molecules, respectively.
Co-reporter:Yu-Ling Liu
Chemical Communications 2017 vol. 53(Issue 45) pp:6077-6080
Publication Date(Web):2017/06/01
DOI:10.1039/C7CC00812K
The host–guest hybrid cyanometallate framework (MA)(H2O)[Sr(H2O)2Co(CN)6] (1; MA = methylammonium) shows thermally and chemically triggered dielectric switching and sensing via a temperature-driven phase transition and a water-driven reversible structure transformation between 1 and its dehydrated form (MA)[SrCo(CN)6].
Co-reporter:Yu-Ling Liu
Inorganic Chemistry Frontiers 2017 vol. 4(Issue 8) pp:1304-1310
Publication Date(Web):2017/08/08
DOI:10.1039/C7QI00218A
Four Cd(II)–Co(III) cyanometallate frameworks have been assembled with the general formula of A2{H(CdCl2)[Co(CN)6]} (A = monovalent organic cation). The cation A is imidazolium (Him) in 1, pyrazolium (Hpa) in 2, guanidinium (Hgu) in 3 and protonated thiourea (Htu) in 4. The common structural feature of the four compounds is the supramolecular rectangular cage which is formed via CN⋯H⋯NC hydrogen bonds between neighboring two-dimensional Cd(II)–Co(III) cyanometallate grids. Variable-temperature X-ray diffraction, differential scanning calorimetry and dielectric constant measurements show that 1, 3, and 4, among the four compounds, exhibit dielectric transitions. The origin of the dielectric responses is attributed to relatively small displacements or thermal vibrations rather than rotational motions of the polar A guests in the rectangular cage. Furthermore, 1 and 4 show unambiguous dielectric relaxations with wide diffusion regions between 120 and 220 K and 1 and 1000 kHz.
Co-reporter:Yu-Ling Sun;Bei-Bei Zheng
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 12) pp:5142-5150
Publication Date(Web):2017/06/12
DOI:10.1039/C7NJ00612H
Three hydrogen-bonded organic salts (HTBA)2(H4ATMP)·(H2O)3 (1), (HTBA)6(H3O)(H2.5ATMP)2·(H2O)2 (2) and (HTBA)6(H3ATMP)2·H2O (3) were synthesized by combining different molar ratios of amino trimethylene phosphonic acid (H6ATMP) and tert-butylamine (TBA). There are three-dimensional hydrogen-bonded networks in 1–3. The crystallization water molecules that are loosely trapped in the supramolecular hydrogen-bonded networks in 1 and 2 undergo order–disorder transitions whose dynamic changes are likely to be responsible for dielectric transitions and relaxations.
Co-reporter:Yu-Ling Sun;Chao Shi
Dalton Transactions 2017 vol. 46(Issue 48) pp:16774-16778
Publication Date(Web):2017/12/12
DOI:10.1039/C7DT03798H
The organic–inorganic hybrid perovskite (H2hpz)[K(ClO4)3] (H2hpz = diprotonated homopiperazine) exhibits a distinct room-temperature dielectric transition. The dielectric switching at 303 K is associated with an order–disorder transition of the polar guest cation confined in the cage, corresponding to a dynamic change between motional and frozen states.
Co-reporter:Xiang-Bin Han
CrystEngComm (1999-Present) 2017 vol. 19(Issue 1) pp:183-184
Publication Date(Web):2016/12/21
DOI:10.1039/C6CE02263D
This Letter is a reply to the preceding comment by Szafrański. We suggest that other probabilities could exist besides Szafrański's assertion on the phase transitions of the crystals and point out how the present experiments and conclusions can be solidified by additional investigations.
Co-reporter:Wen-Ping Zhao, Chao Shi, Alessandro Stroppa, Domenico Di Sante, Fanica Cimpoesu, and Wen Zhang
Inorganic Chemistry 2016 Volume 55(Issue 20) pp:10337-10342
Publication Date(Web):September 27, 2016
DOI:10.1021/acs.inorgchem.6b01545
A displacive-type mechanism, which accounts for the occurrence of ferroelectricity in most inorganic ferroelectrics, is rarely found in molecule-based ferroelectrics. Its role is often covered by the predominant order–disorder one. Herein, we report a lone-pair-electron-driven displacive-type ferroelectric organic–inorganic hybrid compound, [H2dmdap][SbCl5] (1; dmdap = N,N-dimethyl-1,3-diaminopropane). The structure of 1 features a typical zigzag chain of [SbCl5]∞ containing cis-connected anionic octahedra. The compound undergoes a second-order paraelectric–ferroelectric phase transition at 143 K (P21/c ↔ Pc) with a saturation polarization of 1.36 μC·cm–2 and a coercive field of 3.5 kV·cm–1 at 119 K. Theoretical study discloses the ferroelectricity mainly originating from the relative displacements of the Sb and Cl ions in the crystal lattice, which are driven by the 5s2 lone-pair electrons of the SbIII center. Furthermore, on the basis of analysis, possible routes are suggested to enhance ferroelectric polarization in this class of compounds.
Co-reporter:Yu-Ling Liu, Yu-Feng Wang and Wen Zhang
CrystEngComm 2016 vol. 18(Issue 11) pp:1958-1963
Publication Date(Web):05 Feb 2016
DOI:10.1039/C5CE02364E
Inclusion compounds that contain dynamic polar guests possess rich electrical properties such as ferroelectricity and switchable dielectric constant upon undergoing order–disorder-type phase transitions. We here report a thiourea-based inclusion compound (Him)[(TU)2Cl] (Him = imidazolium, TU = thiourea) that undergoes two reversible structural phase transitions at 139 K and 145 K, which are induced by the order–disorder transformations of the Him cation guests in the channels formed by the anionic [(TU)2Cl] components. Switching of the dielectric constant is thus triggered between the low- and high-dielectric states.
Co-reporter:Xiang-Bin Han, Pan Hu, Chao Shi and Wen Zhang
CrystEngComm 2016 vol. 18(Issue 9) pp:1563-1569
Publication Date(Web):27 Jan 2016
DOI:10.1039/C5CE02066B
Two non-centrosymmetric crystals, [(H2dabco)(H2O)](ClO4)2 (1; dabco = 1,4-diazabicyclo[2.2.2]octane) and [(H2dabco)(H2O)](BF4)2 (2), were synthesized and characterized, along with their deuterated species [(D2dabco)(D2O)](ClO4)2 (3) and [(D2dabco)(D2O)](BF4)2 (4). The polar structures are formed by the directional packing of the asymmetric hydrogen-bonded supramolecular unit [(H2dabco)(H2O)] and stabilized by hydrogen bonds among the cations and the anions. Meanwhile, these compounds undergo phase transitions in the temperature range of 230–250 K, revealed by differential scanning calorimetry and dielectric constant measurements. Crystal structure analysis and deuteration study indicate that the order–disorder transition of the anions is the main driving force for the phase transitions in 1 and 2.
Co-reporter:Xiao-Hui Yuan, Xiu-Dan Shao, Chao Shi, Wen Zhang
Inorganic Chemistry Communications 2016 Volume 67() pp:35-39
Publication Date(Web):May 2016
DOI:10.1016/j.inoche.2016.03.001
•Crystals of title compound are obtained via an aqueous solution-evaporation method.•Dielectric transition and relaxation occur between 120 and 180 K.•One of the two HIm cations undergoes a static-dynamic disorder transition.Organic-inorganic hybrid compound (HIm)6[(CdCl4)(CdCl6)] (Im = imidazole) shows a striking dielectric transition and relaxation between 120 and 180 K. Variable-temperature single crystal structure analysis and dielectric measurement reveal one half of the HIm cations in the crystal undergoes a transition between the static and dynamic disorders.Motional changes of one half of the HIm cations in the imidazolium-based crystal (HIm)6[(CdCl4)(CdCl6)] shows dielectric transition and relaxation behaviors between 120 and 180 K.
Co-reporter:Pan Hu, Run-Qiang Zhu, Wen Zhang
Polyhedron 2016 Volume 115() pp:137-141
Publication Date(Web):5 September 2016
DOI:10.1016/j.poly.2016.05.005
Combination of CdCl2 and 1-ethylimidazole (EtIm) with different molar ratios affords three cadmium(II) complexes, i.e., [Cd2(EtIm)4(μ2-Cl)2Cl2] (1), [Cd(EtIm)3Cl2] (2) and [Cd(EtIm)4Cl2] (3). Single-crystal X-ray diffraction analysis reveals the Cl-bridged dinuclear two Cd(II) center ions in 1 have different coordination geometries, that is, one is a cis-pseudo-octahedral (N4Cl2) and the other a pseudo-tetrahedral (Cl4) while the mononuclear Cd(II) center ion adopts a trigonal bipyramidal geometry (N3Cl2) in 2 and a trans-octahedral geometry (N4Cl2) in 3, respectively. Dielectric studies show 1 and 2 undergo dielectric transitions below room temperature and a typical dielectric relaxation behavior is shown in 1, which are caused by the order–disorder transitions of terminal ethyl groups of the EtIm ligands in the crystals.Three cadmium(II) complexes were synthesized from a combination of CdCl2 and 1-ethylimidazole in different molar ratios. They show distinct dielectric behaviors because of the different states of the terminal ethyl groups of the ligands in the crystals.
Co-reporter:Wenping Zhao;Yu Jin
Science China Chemistry 2016 Volume 59( Issue 1) pp:114-121
Publication Date(Web):2016 January
DOI:10.1007/s11426-015-5442-6
Two phase transition compounds, diethylammonium 1,5-naphthalenedisulfonate (1) and cyclohexylammonium 1,5-naphthalenedisulfonate (2), were screened from a series of organic salts based on 1,5-naphthalenedisulfonate. The phase transition behaviors were studied by differential scanning calorimetry, single-crystal X-ray analysis and dielectric measurements. Compounds 1 and 2 undergo phase transitions at about 202 and 148 K, respectively, accompanied by distinct dielectric changes. The origin of the phase transitions was ascribed to motional changes of the cations in the crystal lattices.
Co-reporter:Chao Shi;Chun-Hua Yu ; Wen Zhang
Angewandte Chemie International Edition 2016 Volume 55( Issue 19) pp:5798-5802
Publication Date(Web):
DOI:10.1002/anie.201602028
Abstract
Extended Goldschmidt tolerance factor t is applied to the hybrid double perovskites (MA)2[B′B′′(CN)6] (MA=methylammonium cation) to predict and screen dielectric transitions in 121 compounds through the correlations among t, the radius of the B component rB and the transition temperature Tc, based on experimental results from model compounds. For (MA)2[B′Co(CN)6], it is concluded that: i) when t>0.873, the cubic phase would be stable below 298 K; ii) when 0.873>t>0.805, the cubic phase would be stable between 298 and 523 K; iii) the larger the rB, the higher the Tc of the perovskite (Tc1/2∝rB); and iv) the Tc of the hybrid perovskites can be well tuned by doping the B components.
Co-reporter:Chao Shi;Chun-Hua Yu ; Wen Zhang
Angewandte Chemie 2016 Volume 128( Issue 19) pp:5892-5896
Publication Date(Web):
DOI:10.1002/ange.201602028
Abstract
Extended Goldschmidt tolerance factor t is applied to the hybrid double perovskites (MA)2[B′B′′(CN)6] (MA=methylammonium cation) to predict and screen dielectric transitions in 121 compounds through the correlations among t, the radius of the B component rB and the transition temperature Tc, based on experimental results from model compounds. For (MA)2[B′Co(CN)6], it is concluded that: i) when t>0.873, the cubic phase would be stable below 298 K; ii) when 0.873>t>0.805, the cubic phase would be stable between 298 and 523 K; iii) the larger the rB, the higher the Tc of the perovskite (Tc1/2∝rB); and iv) the Tc of the hybrid perovskites can be well tuned by doping the B components.
Co-reporter:Xi Zhang, Xiu-Dan Shao, Si-Chao Li, Ying Cai, Ye-Feng Yao, Ren-Gen Xiong and Wen Zhang
Chemical Communications 2015 vol. 51(Issue 22) pp:4568-4571
Publication Date(Web):02 Jan 2015
DOI:10.1039/C4CC08693G
A molecular compass-like behaviour is found in a perovskite-type cage compound (HIm)2[KCo(CN)6] (HIm = imidazolium cation). The dynamic changes in the HIm cation from the static to rotating state along with the rearrangement of the host cage result in switchable and anisotropic dielectric constants.
Co-reporter:Xiu-Dan Shao;Xi Zhang;Chao Shi;Ye-Feng Yao
Advanced Science 2015 Volume 2( Issue 5) pp:
Publication Date(Web):
DOI:10.1002/advs.201500029
Co-reporter:Chao Shi, Bin Wei, and Wen Zhang
Crystal Growth & Design 2014 Volume 14(Issue 12) pp:6570-6580
Publication Date(Web):November 13, 2014
DOI:10.1021/cg5014895
A phase transition compound 9PY was screened from a series of organic salts (Cat)·G·NDS, where the Cat is protonated amine or N-containing heterocycle (Cat = methylammonium, 1MA; ethylammonium, 2EA; propylammonium, 3PA; dimethylammonium, 4DMA; isopropylammonium, 5iPA; tert-butylammonium, 6tBA; imidazolium, 7IM; pyrazolium, 8PZ; pyridinium, 9PY; 2-methylimidazolium, 10MIM; 2-ethylimidazolium, 11EIM; (R,S)-3-methylpiperidium, 12MP), the G is guanidinium, and the NDS is 1,5-naphthalenedisulfonate. Detailed crystal structural analysis of 9PY shows the competing hydrogen-bonding interactions among the pyridinium and sulfonates are the driving force for the structural phase transition at 211 K.
Co-reporter:Yu Jin, Chun-Hua Yu, Wen-Xiang Wang, Si-Chao Li, Wen Zhang
Inorganica Chimica Acta 2014 Volume 413() pp:97-101
Publication Date(Web):24 March 2014
DOI:10.1016/j.ica.2014.01.005
•Compounds 1 and 2 have been synthesized and structurally characterized.•Compound 1 has a 2D inorganic anionic layer structure.•Compound 2 contains a rare anionic octanuclear [Cd8Cl25] cluster.•Dielectric properties of 1 and 2 were studied.Reactions of tert-butylamine hydrochloride with cadmium(II) chloride in mixed solutions yield two chlorocadmate(II) compounds, [C4H12N]2[Cd3Cl8] (1) and [C4H12N]9[Cd8Cl25]·(H2O)6 (2). Crystal structures of the two compounds have been determined by X-ray single-crystal diffraction. Compound 1 has a 2D structure in which the inorganic anionic layers are intercalated by tert-butylammonium cations to give an alternated inorganic–organic layered structure. Compound 2, however, is composed of novel anionic octanuclear [Cd8Cl25] clusters, lattice water molecules, and ordered and disordered tert-butylammonium cations. Dielectric constants of both compounds were measured at different temperatures and frequencies.Reactions of tert-butylamine hydrochloride with cadmium(II) chloride in mixed solutions yield two chlorocadmate(II) compounds, 2D-structured [C4H12N]2[Cd3Cl8] (1) and octanuclear cluster-structured [C4H12N]9[Cd8Cl25]·(H2O)6 (2). Dielectric constants of both compounds were measured at different temperatures and frequencies.
Co-reporter:Xiu-Dan Shao, Chao Shi, Chun-Hua Yu, Wen Zhang
Inorganic Chemistry Communications 2014 Volume 47() pp:1-4
Publication Date(Web):September 2014
DOI:10.1016/j.inoche.2014.07.003
•lithium hexacyanocobaltate-based inorganic-organic hybrid compound•three-dimensional metal-cyanide framework•anionic chiral 3D structure composed of helical chains•rich hydrogen bonds among guest molecules and anionic frameworkInorganic–organic hybrid compound (C3H5N2)2(H2O){[Li(H2O)][Co(CN)6]} was synthesized by the reaction of Li3[Co(CN)6] with imidazolium chloride in aqueous solution. It crystallizes in the chiral orthorhombic space group P212121 at 293 K. The anionic chiral 3D structure is composed of helical chains based on the inorganic {[Li(H2O)][Co(CN)6]} building blocks. Imidazolium cations and crystallization water molecules reside in the voids of the anionic framework through rich hydrogen bonds.Anionic chiral 3D structure of (C3H5N2)2(H2O){[Li(H2O)][Co(CN)6]} is composed of helical chains based on the inorganic {[Li(H2O)][Co(CN)6]} building blocks. Imidazolium cations and crystallization water molecules reside in the voids of the anionic framework through rich hydrogen bonds.
Co-reporter:Bin Wei;Ran Shang;Xi Zhang;Xiu-Dan Shao; Ye-Feng Yao; Zhe-Ming Wang; Ren-Gen Xiong; Wen Zhang
Chemistry - A European Journal 2014 Volume 20( Issue 27) pp:8269-8273
Publication Date(Web):
DOI:10.1002/chem.201402892
Abstract
A metal–cyanide framework undergoes a dehydration–rehydration triggered reversible single-crystal-to-single-crystal transformation. The resulting accordion-like contraction–expansion corresponds to a size change along the c axis as much as 24 %. This anisotropic response arises from the cooperativity among the water molecules, K ions, and CN groups between the unique two-dimensional bimetallic layers through weak interactions of hydrogen bonds and electrostatic (ionic) interactions. The key role of the water molecules in the dehydration–rehydration process is revealed by solid-state 1H NMR spectroscopy and dielectric measurements.
Co-reporter:Bin Wei;Ran Shang;Xi Zhang;Xiu-Dan Shao; Ye-Feng Yao; Zhe-Ming Wang; Ren-Gen Xiong; Wen Zhang
Chemistry - A European Journal 2014 Volume 20( Issue 27) pp:
Publication Date(Web):
DOI:10.1002/chem.201490108
Co-reporter:Wen Zhang and Ren-Gen Xiong
Chemical Reviews 2012 Volume 112(Issue 2) pp:1163
Publication Date(Web):September 23, 2011
DOI:10.1021/cr200174w
Co-reporter:Yi Zhang ; Wen Zhang ; Shen-Hui Li ; Qiong Ye ; Hong-Ling Cai ; Feng Deng ; Ren-Gen Xiong ;Songping D. Huang
Journal of the American Chemical Society 2012 Volume 134(Issue 26) pp:11044-11049
Publication Date(Web):June 11, 2012
DOI:10.1021/ja3047427
A novel mononuclear metal–organic compound, [Cu(Hdabco)(H2O)Cl3] (1, dabco = 1,4-diazabicyclo[2.2.2]octane) in which the CuII cation adopts a slightly distorted bipyramidal geometry where the three Cl anions constitute the equatorial plane and the Hdabco cation and H2O molecule occupy the two axial positions, was synthesized. Its paraelectric-to-ferroelectric phase transition at 235 K (Tc) and dynamic behaviors were characterized by single crystal X-ray diffraction analysis, thermal analysis, dielectric and ferroelectric measurements, second harmonic generation experiments, and solid-state nuclear magnetic resonance measurements. Compound 1 behaves as a molecular rotor above room temperature in which the (Hdabco) part rotates around the N···N axis as a rotator and the [Cu(H2O)Cl3] part acts as a stator. In the temperature range 235–301 K, a twisting motion of the rotator is confirmed. Below the Tc, the motions of the rotor are frozen and the molecules become ordered, corresponding to a ferroelectric phase. Origin of the ferroelectricity was ascribed to relative movements of the anions and cations from the equilibrium position, which is induced by the order–disorder transformation of the twisting motion of the molecule between the ferroelectric and paraelectric phases. Study of the deuterated analogue [Cu(Ddabco)(D2O)Cl3] (2) excludes the possibility of proton ordering as the origin of the ferroelectricity in 1.
Co-reporter:Wen Zhang;RuiJun Xu
Science China Chemistry 2012 Volume 55( Issue 2) pp:201-207
Publication Date(Web):2012 February
DOI:10.1007/s11426-011-4401-0
Solid-state phase transitions of 4-methylanilinium perchlorate (4-CH3C6H4NH3·ClO4, 1) and tetrafluoroborate (4-CH3C6H4-NH3·BF4, 2) were investigated with variable-temperature X-ray single-crystal structure analysis and thermal studies. Both 1 and 2 undergo first-order phase transitions and exhibit distinct dielectric anomalies at 385 and 247 K, respectively.
Co-reporter:Tian Hang, Wen Zhang, Heng-Yun Ye and Ren-Gen Xiong
Chemical Society Reviews 2011 vol. 40(Issue 7) pp:3577-3598
Publication Date(Web):20 Apr 2011
DOI:10.1039/C0CS00226G
Ferroelectric materials are of importance and interest in both fundamental scientific research and various technological applications. Metal–organic complexes (MOCs) represent a class of molecule-based ferroelectrics, which have shown various properties or functionalities due to their hybrid inorganic–organic nature. This tutorial review shows the recent development of the MOC ferroelectrics with particular emphases on the mechanism of ferroelectric-to-paraelectric phase transition, symmetry consideration, and multifunctionality.
Co-reporter:Da-Wei Fu;Hong-Ling Cai;Jia-Zhen Ge;Yi Zhang ;Ren-Gen Xiong
Advanced Materials 2011 Volume 23( Issue 47) pp:5658-5662
Publication Date(Web):
DOI:10.1002/adma.201102938
Co-reporter:Da-Wei Fu ; Wen Zhang ; Hong-Ling Cai ; Yi Zhang ; Jia-Zhen Ge ; Ren-Gen Xiong ;Songping D. Huang
Journal of the American Chemical Society 2011 Volume 133(Issue 32) pp:12780-12786
Publication Date(Web):July 11, 2011
DOI:10.1021/ja204540g
Molecular motion is one of the structural foundations for the development of functional molecular materials such as artificial motors and molecular ferroelectrics. Herein, we show that pendulum-like motion of the terminal group of a molecule causes a ferroelectric phase transition. Complex 4-methoxyanilinium tetrafluoroborate-18-crown-6 ([C7H10NO(18-crown-6)]+[BF4]−, 1) shows a second-order ferroelectric phase transition at 127 K, together with an abrupt dielectric anomaly, Debye-type relaxation behavior, and the symmetry breaking confirmed by temperature dependence of second harmonic generation effect. The origin of the polarization is due to the order–disorder transition of the pendulum-like motions of the terminal para-methyl group of the 4-methoxyanilinium guest cation; that is, the freezing of pendulum motion at low temperature forces significant orientational motions of the guest molecules and thus induces the formation of the ferroelectric phase. The supramolecular bola-like ferroelectric is distinct from the precedent ferroelectrics and will open a new avenue for the design of polar functional materials.
Co-reporter:De-Hong Wu, Jia-Zhen Ge, Hong-Lin Cai, Wen Zhang and Ren-Gen Xiong
CrystEngComm 2011 vol. 13(Issue 1) pp:319-324
Publication Date(Web):08 Sep 2010
DOI:10.1039/C0CE00109K
4-Ethylanilinium hydrogen (2R,3R)-tartrate, a novel wide-temperature-range ferroelectric was synthesized. DSC measurement discloses that the homochiral organic salt undergoes an isosymmetric reversible phase transition at about 186 K with a sharply narrow heat hysteresis of 0.7 K. The heat capacity Cp obtained from the calorimetric measurement exhibits a sharp peak at 185.8 K, characteristic of a first-order phase transition. However temperature-dependence dielectric constant measurements reveal no dielectric anomaly near the phase transition point. The measurement of the unit cell parameters except for c axis versus temperature suggests that the values change abruptly and remarkably between 180 and 190 K with the cell volume doubled. The crystal structures determined at 123(2) K (a = 7.461 Å, b = 11.930 Å, c = 14.873 Å, α = 95.34°, β = 91.95°, γ = 107.92°) and 298(2) K (a = 6.078 Å, b = 7.478 Å, c = 14.951 Å, α = 87.66°, β = 82.69°, γ = 71.80°) also show that the phase transition could be a type of isosymmetric change with the same triclinic space group P1 (No. 1). Structural analysis shows that the different modes of hydrogen bonds probably affect the configurations of the phenyl rings from the cations, consequently leading to a reversible structural phase transition.
Co-reporter:Wei-Wei Sima, Wen Zhang
Inorganic Chemistry Communications 2011 Volume 14(Issue 1) pp:176-179
Publication Date(Web):January 2011
DOI:10.1016/j.inoche.2010.10.016
Two heterotrimetallic compounds, [Cu(en)2Li(H2O)][Fe(CN)6] and [Cu(en)2Li(H2O)][Co(CN)6] (en = ethylenediamine), were synthesized and characterized. They are isostructural and crystallize in the orthorhombic space group Pbca at 293 K. The structures of the two compounds are composed of one-dimensional zigzag Fe/Co–C≡N–Cu chains linked by Li(I) ions into three-dimensional frameworks. Magnetic study of [Cu(en)2Li(H2O)][Fe(CN)6] reveals a weak magnetic interaction in the compound.Two heterotrimetallic compounds, [Cu(en)2Li(H2O)][Fe(CN)6] and [Cu(en)2Li(H2O)][Co(CN)6] (en = ethylenediamine), were synthesized and characterized. They are isostructural and crystallize in the orthorhombic space group Pbca at 293 K. The structures of the two compounds are composed of one-dimensional zigzag Fe/Co−C≡N−Cu chains linked by Li(I) ions into three-dimensional frameworks. Magnetic study of [Cu(en)2Li(H2O)][Fe(CN)6] reveals a weak magnetic interaction in the compound.Research Highlights► Heterotrimetallic compounds [Cu(en)2Li(H2O)][M(CN)6] (M = Fe(III) or Co(III); en = ethylenediamine) are composed of one-dimensional zigzag M − C ≡ N − Cu chains linked by Li(I) ions into three-dimensional frameworks. ► Magnetic measurements of [Cu(en)2Li(H2O)][Fe(CN)6] reveal a weak magnetic interaction. ► This study shows the possibility of using a third diamagnetic metal ion to control structures and magnetic properties of Cu(II)-Fe(III)-cyanide compounds.
Co-reporter:Da-Wei Fu; Wen Zhang;Dr. Hong-Ling Cai;Dr. Yi Zhang;Dr. Jia-Zhen Ge; Ren-Gen Xiong; Songping D. Huang ; Takayoshi Nakamura
Angewandte Chemie International Edition 2011 Volume 50( Issue 50) pp:11947-11951
Publication Date(Web):
DOI:10.1002/anie.201103265
Co-reporter:Da-Wei Fu; Wen Zhang;Dr. Hong-Ling Cai;Dr. Yi Zhang;Dr. Jia-Zhen Ge; Ren-Gen Xiong; Songping D. Huang ; Takayoshi Nakamura
Angewandte Chemie 2011 Volume 123( Issue 50) pp:12153-12157
Publication Date(Web):
DOI:10.1002/ange.201103265
Co-reporter:Rui-Jun Xu;Yan Cui
Journal of Chemical Crystallography 2011 Volume 41( Issue 6) pp:779-782
Publication Date(Web):2011 June
DOI:10.1007/s10870-010-9973-6
Evaporation of the mixture solution of Cu(ClO4)2·6H2O, KOH and (S)-2-hydroxy-3-phenylpropanoic acid affords a Cu(II)–K(I) coordination compound 1. Single-crystal X-ray diffraction analysis reveals that 1 is a one-dimensional comb-like coordination polymer in the P212121 space group with crystal cell parameters a = 10.989(2) Å, b = 15.939(3) Å, c = 22.511(5) Å, V = 3943(1) Å3 and Z = 4.
Co-reporter:Wen Zhang ;Ying Cai;Ren-Gen Xiong ;Hirofumi Yoshikawa ;Kunio Awaga
Angewandte Chemie 2010 Volume 122( Issue 37) pp:6758-6760
Publication Date(Web):
DOI:10.1002/ange.201001208
Co-reporter:Wen Zhang ;Ying Cai;Ren-Gen Xiong ;Hirofumi Yoshikawa ;Kunio Awaga
Angewandte Chemie International Edition 2010 Volume 49( Issue 37) pp:6608-6610
Publication Date(Web):
DOI:10.1002/anie.201001208
Co-reporter:Jing-Mei Xiao, Wen Zhang
Inorganic Chemistry Communications 2009 Volume 12(Issue 12) pp:1175-1178
Publication Date(Web):December 2009
DOI:10.1016/j.inoche.2009.09.002
Two chiral Schiff base-containing complexes, [Cu(L1)](ClO4)2·H2O (1, L1 = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L2)2](ClO4)2 (2, L2 = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO4)2·6H2O or Ni(ClO4)2·6H2O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L1 and L2 are bisubstituted and monosubstituted, respectively, corresponding to the different metal ions CuII and NiII. Variable-frequency and -temperature dielectric properties of 1 and 2 have been studied.One-pot approach in the presence of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO4)2·6H2O or Ni(ClO4)2·6H2O in methanol gives rise to the bisubstituted and monosubstituted chiral Schiff base-containing compounds 1-Cu and 2-Ni, respectively. Both complexes show normal dielectric behaviors at room temperature with ignorable dielectric losses.
Co-reporter:Da-Wei Fu, Wen Zhang and Ren-Gen Xiong
Dalton Transactions 2008 (Issue 30) pp:3946-3948
Publication Date(Web):03 Jun 2008
DOI:10.1039/B806255B
Hydrothermal reaction of H-Imazethapyr (2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-5-ethyl-3-pyridinecarboxylic acid) with Cd(ClO4)2·6H2O offers a diamond-like MOF 1Cd(Imazethapyr)2 in which it crystallizes in a non-centrosymmetric space group (Fdd2) belonging to polar point group (C2v). MOF 1 displays a strong SHG response, and good ferroelectric and piezoelectric properties.
Co-reporter:Wen Zhang ; Heng-Yun Ye ; Robert Graf ; Hans W. Spiess ; Ye-Feng Yao ; Run-Qiang Zhu ;Ren-Gen Xiong
Journal of the American Chemical Society () pp:
Publication Date(Web):March 21, 2013
DOI:10.1021/ja3110335
The inclusion compound [(CH3)2NH2]2[KCo(CN)6] exhibits a marked temperature-dependent dielectric constant and can be considered as a model of tunable and switchable dielectric materials. Crystal structure and solid-state NMR studies reveal a switchable property between low and high dielectric states around 245 K. This originates from an order–disorder phase transition of the system, changing the dynamics of the polar dimethylammonium (DMA) cation. Furthermore, the tuning of the dielectric constant at temperatures below the phase transition point is related to increasing angular pretransitional fluctuations of the dipole moment of DMA.
Co-reporter:Chao Shi, Xiang-Bin Han, Ya Wang and Wen Zhang
Inorganic Chemistry Frontiers 2016 - vol. 3(Issue 12) pp:
Publication Date(Web):
DOI:10.1039/C6QI00347H
Co-reporter:Yu-Ling Liu and Wen Zhang
Chemical Communications 2017 - vol. 53(Issue 45) pp:NaN6080-6080
Publication Date(Web):2017/04/07
DOI:10.1039/C7CC00812K
The host–guest hybrid cyanometallate framework (MA)(H2O)[Sr(H2O)2Co(CN)6] (1; MA = methylammonium) shows thermally and chemically triggered dielectric switching and sensing via a temperature-driven phase transition and a water-driven reversible structure transformation between 1 and its dehydrated form (MA)[SrCo(CN)6].
Co-reporter:Tian Hang, Wen Zhang, Heng-Yun Ye and Ren-Gen Xiong
Chemical Society Reviews 2011 - vol. 40(Issue 7) pp:NaN3598-3598
Publication Date(Web):2011/04/20
DOI:10.1039/C0CS00226G
Ferroelectric materials are of importance and interest in both fundamental scientific research and various technological applications. Metal–organic complexes (MOCs) represent a class of molecule-based ferroelectrics, which have shown various properties or functionalities due to their hybrid inorganic–organic nature. This tutorial review shows the recent development of the MOC ferroelectrics with particular emphases on the mechanism of ferroelectric-to-paraelectric phase transition, symmetry consideration, and multifunctionality.
Co-reporter:Da-Wei Fu, Wen Zhang and Ren-Gen Xiong
Dalton Transactions 2008(Issue 30) pp:NaN3948-3948
Publication Date(Web):2008/06/03
DOI:10.1039/B806255B
Hydrothermal reaction of H-Imazethapyr (2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-5-ethyl-3-pyridinecarboxylic acid) with Cd(ClO4)2·6H2O offers a diamond-like MOF 1Cd(Imazethapyr)2 in which it crystallizes in a non-centrosymmetric space group (Fdd2) belonging to polar point group (C2v). MOF 1 displays a strong SHG response, and good ferroelectric and piezoelectric properties.
Co-reporter:Xi Zhang, Xiu-Dan Shao, Si-Chao Li, Ying Cai, Ye-Feng Yao, Ren-Gen Xiong and Wen Zhang
Chemical Communications 2015 - vol. 51(Issue 22) pp:NaN4571-4571
Publication Date(Web):2015/01/02
DOI:10.1039/C4CC08693G
A molecular compass-like behaviour is found in a perovskite-type cage compound (HIm)2[KCo(CN)6] (HIm = imidazolium cation). The dynamic changes in the HIm cation from the static to rotating state along with the rearrangement of the host cage result in switchable and anisotropic dielectric constants.
