Controllable Structures Designed with Multiple-Dielectric Responses

Article pubs.acs.org/IC

Controllable Structures Designed with Multiple-Dielectric Responses in Hybrid Perovskite-Type Molecular Crystals Zhongxia Wang,* Yang Lu, Hai-Peng Chen, and Jia-Zhen Ge* Ordered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People’s Republic of China S Supporting Information *

ABSTRACT: In this report, two new hybrid organic−inorganic perovskite-type compounds, (IBA)CdBr3 (1; IBA = isobutylammonium cation, i-C4H9-NH3) and (IBA)2CdBr4 (2), have been successfully synthesized by reasonable modulation of the ratio of the reactants. 1 with a one-dimensional (1D) chained structure presents sequential solid-state phase transitions, and 2 with a twodimensional (2D) layered structure undergoes triple structural phase transitions. The phase transitions are attributable to the stepwise ordering process of the organic IBA cation of the title compounds, which also exhibit temperature-dependent dielectric transitions and dielectric anisotropies. Among the different structural environments, the dynamic motions of organic cations show distinct differences, driving the variation of physical properties.

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materials.30−40 For instance, (C3H4NS)CdBr3 with a 1D hybrid perovskite-type structure experiences structural phase transitions associated with the motion of the organic cation.41 Moreover, the organic−inorganic hybrid (C4H9-NH3)2PbBr4 with a 2D layered structure displays sequential structural phase transitions and switchable dielectric responses.42 In addition, some copper-based 2D layered organic−inorganic hybrid halides have been reported with promising multistep dielectric transitions and multiferroic character.43−45 It is notable that the 2D layered hybrid compound (benzylammonium)2PbCl4 demonstrates prominent ferroelectric semiconductor character and (cyclohexylammonium)2PbBr4 presents readily tunable ferroelectric and photovoltaic properties.46,47 These kinds of adjustable properties make hybrid compounds optimal choices for designing multifunctional materials. More importantly, a molecular system with controllable structure would promote novel physical properties.48,49 Nonetheless, compounds with controllable structures from 1D chain to 2D layered configuration resulting in adjustable dielectric phase transition properties have been rarely reported in perovskite-type organic−inorganic hybrids. Herein, in the process of exploring dielectric phase transition materials, we found two new structure-controllable organic− inorganic hybrid compounds: (IBA)CdBr 3 (1) and (IBA)2CdBr4 (2). The two compounds prepared by changing the ratio of reactants display multiple structural phase transitions, accompanied by noteworthy dielectric responses.

INTRODUCTION Phase transition materials sensitive to external stimuli (e.g., temperature, pressure, magnetic field) have drawn great interest because of their applicable uses as excellent sensors, switches, and memory devices.1−6 A molecular system inherently contained with distinct molecular motions is the crucial factor for its phase transition properties. Due to the local dynamic motions such as molecular rotation, atomic displacement, etc., the changes in molecular structure can trigger different macro physical properties.7−9 Subsequently, some promising physical characteristics (e.g., electric, optic, and magnetic properties) will appear in the compounds with phase transitions induced by molecular motions. Among these intriguing features, dielectric response is generally companied by the occurrence of a phase transition, in which the dielectric switchings between high and low states show good performance in data communication and processing etc.10 The origin of the dielectric phase transition is attributed to the motional-frozen transitions of the polar components. Hence, molecular order−disorder transitions have gradually evolved into effective methods of exploring new phase transition materials accompanied by promising dielectric properties.11−18 Recently, organic−inorganic hybrid perovskite compounds with diversified structures have received increasing interest owing to a variety of intriguing properties, ranging from optical and photovoltaic properties to ferroelectric properties.19−29 In these valuable works, the organic components residing in the space enclosed by an inorganic anionic framework, creating suitable environments for the dynamic motion of the cation, have been extended to the studies of dielectric phase transition © 2017 American Chemical Society

Received: March 13, 2017 Published: May 31, 2017 7058

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

Article

Inorganic Chemistry

203 K, and T2c = 161 K were detected in 2 (Figure 1b), in which the distinct thermal hysteresis (ca. 20 K) during the cooling and heating runs suggests a discontinuous first-order feature of phase transitions.50−53 For convenience, the phase above T1a and T2a was designated as the high-temperature phase (HTP), the phase between the two phase transition points (T1a and T1b for 1 or T2a and T2c for 2) as the intermediate-temperature phase (ITP), and the phase below T1b and T2c as the low-temperature phase (LTP). Especially, the ITP of 2 contains two states and has been divided into two further phases: namely, ITP-α for the relatively high temperature phase and ITP-β for another phase. The entropy changes (ΔS) for phase transitions in the cooling processes of 1 and 2 were calculated to be approximately 0.38 J mol−1 K−1 at T1a, 4.19 J mol−1 K−1 at T1b, 0.66 J mol−1 K−1 at T2a, 0.45 J mol−1 K−1 at T2b, and 6.17 J mol−1 K−1 at T2c, respectively. The ratios of respective geometrically distinguishable orientations N(T1a), N(T1b), N(T2a), N(T2b), and N(T2c), based on the Boltzmann equation ΔS = R ln N, where R is the gas constant, are estimated to be 1.05, 1.65, 1.08, 1.06, and 2.10, respectively. These results readily prove the order−disorder feature of the phase transition at T1b and T2c.5 However, the complicated phase transition at T1a, T2a, and T2b will be verified in the section on structural analysis. Crystal Structures. Variable-temperature structural analyses of 1 and 2 were performed to fully understand the details of structural changes in all phases, and brief crystallographic data are given in Table 1. In the HTP (293 K), 1 crystallizes in the orthorhombic crystal system with the space group Cmcm (No. 63). The packing structure of 1 contains infinite chains of face-sharing CdBr6 octahedron along the c axis separated by the IBA cations (Figure 2a). The asymmetric unit consists of one IBA cation, one Cd atom, and two Br atoms (Figure 2c). The Cd−Br bond length (2.737(5)−2.807(5) Å) and the adjacent Br atom angles (Br−Cd−Br) ranging from 85.81(3) to 94.19(14)° of the octahedrally coordinated Cd1 atom contribute to the weak distortion of the CdBr6 octahedron (Table S1 in the Supporting Information). These bond lengths and bond angles are comparable to those in other reported structurally similar bromocadmate(II) compounds, such as [C5H6N][CdBr3]25 and [C3H4NS][CdBr3].38 The IBA cation sits on a special position of the 2mm symmetry site, which requires all atoms to be distributed equally over the two mirror planes (110) and (011) (Figure 2c). Significantly, the IBA cation forms weak hydrogen-bonding interactions with the anionic framework with donor−acceptor distances N···Br of 3.68 and 3.92 Å, respectively (Table S2 in the Supporting Information), which give the IBA cation great freedom for dynamic motion. The ITP of 1 has a packing structure similar to that in the HTP (Figure 2b). It is worth mentioning that the space group drops to Pnma (No. 62) with a decrease in temperature, and the cell parameters are also changed (Table 1). The relationship of the cells is a243 K ≈ b293 K, b243 K ≈ c293 K, and c243 K ≈ a293 K. The basic unit in the ITP consists of one Cd atom, three Br atoms, and one IBA cation. The geometry of the [CdBr3]n− chains presents no obvious changes, as the Cd−Br bond length (2.775 Å) and Br−Cd−Br bond angles (85.24(17)−94.77(4)°) are similar to those in the HTP (Table S1 in the Supporting Information). Differently, the infinite chain direction changes to the b axis and the IBA cation is located on the special position of m symmetry sites, where the disordered cation has two equivalent orientations required

Systematic characterizations indicate that the gradually slowing dynamic motions of the IBA cation give rise to the dielectric phase transitions of the two compounds.

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EXPERIMENTAL SECTION

Synthetic Procedures. All of the chemical reagents were purchased from Aladdin Reagent Co., Ltd., and used without any further purification. Large blocklike crystals of 1 (Figure S1a in the Supporting Information) were prepared by evaporation of aqueous solutions containing CdBr2 (100 mmol) and isobutylammonium bromide (50 mmol) at room temperature. Large colorless flakelike single crystals of 2 (Figure S1b) were obtained by slow evaporation of a CdBr2 (50 mmol) and isobutylammonium bromide (100 mmol) mixed solution with HBr (20 mL) at room temperature after 2 weeks. Phase purities of 1 and 2, in the form of polycrystalline samples, were determined by their variable-temperature powder X-ray diffraction (VT-PXRD) patterns, matching well the simulated patterns in terms of the crystal structures with the corresponding temperatures (Figures S2 and S3 in the Supporting Information). In addition, the infrared (IR) spectra of 1 and 2 were recorded and the results showed similar peaks at the same wavenumbers due to the same IBA cation (Figure S4 in the Supporting Information). Methods. Differential scanning calorimetry (DSC), variabletemperature single-crystal diffraction, and dielectric measurements were performed to confirm the phase transitions of compounds 1 and 2. For dielectric anisotropy measurements, the single-crystal samples of the two compounds were cut into thin plates along the three crystal axes.

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RESULTS AND DISCUSSION Thermal Properties. Two reversible heat anomalies at 260/265 K (T1a) and 227/234 K (T1b) upon cooling/heating runs were observed in the DSC curve of 1 (Figure 1a). The

Figure 1. DSC curves of 1 (a) and 2 (b).

relatively small thermal hysteresis and broad thermal anomalies around T1a indicate that the transition is of discontinuous first order. In addition, the anomaly around T1b in 1 with larger thermal hysteresis and λ peak demonstrates a continuous second-order type of phase transition.27,28 Differently, three pairs of exothermic peaks at approximately T2a = 241 K, T2b = 7059

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

Article

Inorganic Chemistry Table 1. Crystal Data and Structure Refinement Details for 1 and 2 (C4H9NH3)CdBr3 (1) T (K) formula wt space group a/Å, b/Å, c/Å V/Å3 Z F(000) no. of collected rflns no. of unique rflns no. of params refined GOF R1, wR2 (I > 2σ(I))

(C4H9NH3)2CdBr4 (2)

293 426.26 Cmcm 7.78(3), 20.19(5), 6.864(16) 1079 (5) 4 892 3920

243 426.26 Pnma 20.10(6), 6.846(19), 7.76(3) 1067 (6) 4 784 7362

283 580.30 Cmca 7.977(12), 28.06(4), 8.025(11) 1796(4) 4 1168 4704

243 580.30 Cmca 8.063(16), 28.45(5), 8.10(3) 1858(8) 4 1168 4935

193 580.30 Cmca 7.93(3), 28.12(8), 7.98(2) 1781(9) 4 1168 4349

93 580.30 Aba2 7.935(15), 28.41(5), 7.793(15) 1757(6) 4 1096 7003

719 49

1321 62

854 58

885 55

839 52

1539 73

1.16 0.058, 0.196

1.19 0.073, 0.234

1.15 0.087, 0.232

1.10 0.104, 0.277

1.09 0.123, 0.272

1.17 0.143, 0.325

Figure 2. Packing views of 1 at (a) 293 K and (b) 243 K. Molecular structures of 1 at (c) 293 K (HTP), where the IBA cation shows orientational disorder and occupies the special position on two mirror planes, (110) (.1., blue plane) and (011) (.2., red plane), and (d) 243 K (ITP), where the IBA cation maintains orientational disorder and occupies the special position on a mirror plane (101) (.3., red plane). Hydrogen atoms were omitted for clarity.

by the symmetry plane (101) (Figure 2d). Obviously, as the temperature decreases, the IBA cation becomes relatively ordered. The amine groups of the IBA cation form weak hydrogen-bonding interactions with the anionic [CdBr3]n− network in a manner analogous to those in the HTP. The average N−H···Br hydrogen bond distance is 3.03 Å (Table S2 in the Supporting Information), providing the cation with enough freedom for dynamic motion. The collection of crystal diffraction data with good quality in the LTP was unsuccessful. Fortunately, the rough structure was refined and the cell parameters were defined as a = 6.823(10) Å, b = 20.18(3) Å, c = 9.819(13) Å, β = 128.24(8)°, and V = 1062(3) Å3 with the monoclinic space group P21/c (No. 14). The organic cation in the LTP shows an ordered state in the arrangement (Figure S5 in the Supporting Information). The simulated powder diffraction pattern matches very well with the measured pattern, indicating that the refined structure at 213 K in the LTP is reasonable (Figure S6 in the Supporting Information). To further reveal the structure changes, VTPXRD measurements were performed. As shown in Figure 3, when the temperature decreased from 243 to 193 K, the

Figure 3. Variable-temperature PXRD patterns of 1 in cooling mode between 293 and 193 K.

diffraction peaks at 27.92, 32.09, 36.26, and 39.54° disappeared. Four new diffraction peaks were observed at 22.51, 31.19, 32.66, and 41.00°. The prominent variations of the PXRD patterns obviously indicate the occurrence of a structural phase 7060

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

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generally displays obvious anomalies close to the phase transition point. The temperature-dependent dielectric real part (ε′) and imaginary part (ε″) of the complex dielectric permittivity were measured on the polycrystalline and singlecrystal samples at 10, 100, and 1000 kHz over the temperature range from 120 to 280 K. As depicted in Figure 5, 1 shows

transition in the cooling run, agreeing well with the DSC results. When 1 is cooled to 213 K, the mirror symmetry in the ITP (Figure 2d) breaking occurs, resulting in a completely ordered IBA cation (Figure S5 in the Supporting Information). The molecular structure of 2 is a rarely reported cadium bromide layered organic−inorganic perovskite-type configuration, containing infinite octahedral corner-sharing [CdBr4]n2− layers filled by IBA cations (Figure 4a). At 283 K in the HTP,

Figure 5. Temperature dependence of the real part (ε′) and dielectric imaginary part (ε″) of the polycrystalline sample of 1.

double pronounced anomalies of dielectric constant. Such results strongly confirm the occurrence of phase transitions in 1, well consistent with the DSC thermal analyses. It should be emphasized that the ε′ value demonstrates two turning points with three distinct plateaus, showing sequential dielectric switching properties. Above T1a, ε′ is about 11 (1000 kHz). Approaching T1a, ε′ decreases slowly to about 10 in a cooling run. Upon further cooling to T1b, the value of ε′ gradually drops to around 6.5. The imaginary part of the dielectric constant also displays a distinct anomaly peak around T1b (Figure 5, inset). Such behaviors disclose the potential dielectric double switches in 1. In addition, ε′ at T1a shows a slight increase with the frequency decrease, but ε′ at T1b almost remains unchanged at different frequencies, indicating that the dielectric constant has no frequency dependence at T1b (Figure 6). Dielectric anisotropies along three crystallographic axes are another important feature.45−48 A visible small dielectric anomaly at around T1a in 1 is only recorded along the c axis (Figure 7, inset). This result may be attributed to the order− disorder change of the IBA cation along the c axis from the HTP to ITP. When the temperature dropped to T1b, the

Figure 4. Molecular structures of 2 shown at different temperatures: (a) perspective packing view of 2 in the HTP; (b) dynamic changes of the IBA cation in different phases with an decrease in temperature. Hydrogen atoms are omitted for clarity.

the Cd−Br bond distances (2.634(4)−2.842(3) Å) and Br− Cd−Br bond angle (89.14(12)−90.86(12)°) give a slightly distorted octahedral geometry (Table S3 in the Supporting Information). As illustrated in Figure 4b, the IBA cation in the HTP is located on an m symmetry site with a mirror plane perpendicular to the (100) direction. Equivalent orientational disorder with all C atoms of the cation distributing over the mirror plane appears to satisfy the requirements of the symmetry. The NH3+ group of the IBA cation forms weak hydrogen-bonding interactions with Br atoms (N···Br = 3.62(2) Å) (Table S5 in the Supporting Information), which causes relative freedom for the motion of the cation. In ITP-α and ITP-β (Figure 4b), the anionic framework remains similar to that in the HTP (Table S4 in the Supporting Information). However, the orientation state of the cation presents distinct changes, with the step-ordered C4 and C3 located on the mirror plane, respectively. The phase transitions from the HTP to ITP with the unchanged space group can be identified as the structural changes from the dynamic disorder state to the static disorder state. In the LTP, the space group changes to Aba2 and the IBA cation becomes ordered with a single state. Correspondingly, symmetry breaking occurs, accompanied by the mirror symmetry (100) disappearing. Dielectric Properties. The variable-temperature dielectric response is sensitive to the structural phase transition and

Figure 6. Dielectric permittivities (ε′) of 1 and 2 (inset) measured over the frequency range of 10−1000 kHz in a cooling run. 7061

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

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of the IBA cation. Broad dielectric peaks along the c and a axes have a relatively greater ε′ value change of about 6 at around T2c, while that along the b axis is much smaller with a value change of about 1.5. This is due to the reorientation of the disordered IBA cation, which involves a motion between two sides of the crystallographic mirror plane perpendicular to the (100) direction, in accordance with the structural analysis results. In addition, dielectric constants of the polycrystalline sample at low frequencies are more noticeable than those at f = 1000 kHz, suggesting that it is a potential frequency dependent dielectric material (Figure 6, inset).

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CONCLUSION In conclusion, the present work has successfully presented two new structure-controllable organic−inorganic hybrid perovskite-type compounds (isobutylammonium)CdBr3 and (isobutylammonium)2CdBr4, which were prepared by changing the ratio of reactants. The two compounds present completely different structure models and phase transition behaviors, including phase transition temperatures and dielectric anomalies. The combined DSC, variable-temperature structural analyses, and variable-temperature PXRD patterns confirm the occurrence of phase transitions. Such results indicate that the dielectric phase transitions can be inherently ascribed to the order−disorder transitions of the isobutylammonium cation, which shows obvious differences in the dynamic motions between the two compounds. The adjustable structures and physical properties in a molecular system would facilitate better performance. It is expected that our findings will open a new dimension in the search for novel functional materials of organic−inorganic hybrids with tuning properties.

Figure 7. Anisotropic dielectric permittivity (ε′) of 1 along a, b, and c axes at f = 1000 kHz in a cooling run.

dielectric state rapidly switched to the low dielectric state with the largest change in ε′ along the c axis, while a comparatively smaller anomaly was recorded along the b axis with a broad peak and the smallest ε′ value change occurred in the direction of the a axis (Figure 7, inset). This dielectric anisotropy property is caused by the special position of the IBA cation, which is perpendicular to ab plane in the HTP and thus the motion can only occur along the c axis. Therefore, the dynamic behavior of the IBA cation causes the weak dielectric anomaly along the a axis around T1b. Dielectric measurements in 2 applied on a polycrystalline sample and crystals along different axes are presented in Figure 8. Three anomalies were clearly observed in the polycrystalline

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.7b00662. Methods, characterization data, and crystal data of 1 and 2 (PDF) Accession Codes

CCDC 1495220−1495225 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Authors

*E-mail for Z.W.: [email protected]. *E-mail for J.-Z.G.: [email protected].

Figure 8. Dielectric permittivity (ε′) of 2 along the a, b, and c axes and a polycrystalline sample in a cooling run.

ORCID

Zhongxia Wang: 0000-0002-6375-1712 Jia-Zhen Ge: 0000-0002-0971-2616

samples. Additionally, tiny steplike dielectric anomalies at around T2a along the c and a axes were detected, while no observable anomaly was recorded in the direction of the b axis, indicating that the motion of the IBA cation involves the shift of the positive charge carried by the ammonium head only along the c and a directions. Anomalies in the vicinity of T2b measured along three axes reveal the complex dynamic motion

Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (21531008) and the Scientific Research 7062

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

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Inorganic Chemistry

(21) Wehrenfennig, C.; Eperon, G. E.; Johnston, M. B.; Snaith, H. J.; Herz, L. M. High Charge Carrier Mobilities and Lifetimes in Organolead Trihalide Perovskites. Adv. Mater. 2014, 26, 1584−1589. (22) Dohner, E. R.; Jaffe, A.; Bradshaw, L. R.; Karunadasa, H. I. Intrinsic White-Light Emission from Layered Hybrid Perovskites. J. Am. Chem. Soc. 2014, 136, 13154−13157. (23) Cao, D. H.; Stoumpos, C. C.; Farha, O. K.; Hupp, J. T.; Kanatzidis, M. G. 2D Homologous Perovskites as Light-Absorbing Materials for Solar Cell Applications. J. Am. Chem. Soc. 2015, 137, 7843−7850. (24) Xu, G. C.; Zhang, W.; Ma, X. M.; Chen, Y. H.; Zhang, L.; Cai, H. L.; Wang, Z. M.; Xiong, R.-G.; Gao, S. Coexistence of Magnetic and Electric Orderings in the Metal−Formate Frameworks of [NH4][M(HCOO)3]. J. Am. Chem. Soc. 2011, 133, 14948−14951. (25) Zhang, Y.; Ye, H. Y.; Zhang, W.; Xiong, R.-G. RoomTemperature ABX3-Typed Molecular Ferroelectric:[C5H9-NH3][CdCl3]. Inorg. Chem. Front. 2014, 1, 118−123. (26) Ye, H. Y.; Zhang, Y.; Fu, D. W.; Xiong, R.-G. An Above-RoomTemperature Ferroelectric Organo-Metal Halide Perovskite:(3-Pyrrolinium) (CdCl3). Angew. Chem., Int. Ed. 2014, 53, 11242−11247. (27) Zhang, Y.; Liao, W. Q.; Fu, D. W.; Ye, H. Y.; Chen, Z. N.; Xiong, R.-G. Highly Efficient Red-Light Emission in An OrganicInorganic Hybrid Ferroelectric:(Pyrrolidinium) MnCl3. J. Am. Chem. Soc. 2015, 137, 4928−4931. (28) Zhang, Y.; Liao, W. Q.; Fu, D. W.; Ye, H. Y.; Liu, C. M.; Chen, Z. N.; Xiong, R.-G. The First Organic-Inorganic Hybrid Luminescent Multiferroic:(Pyrrolidinium) MnBr3. Adv. Mater. 2015, 27, 3942− 3946. (29) Sun, Z. H.; Liu, X. T.; Khan, T.; Ji, C. M.; Asghar, M. A.; Zhao, S. G.; Li, L. N.; Hong, M. C.; Luo, J. H. A Photoferroelectric Perovskite-Type Organometallic Halide with Exceptional Anisotropy of Bulk Photovoltaic Effects. Angew. Chem., Int. Ed. 2016, 55, 6545− 6550. (30) Lemmerer, A.; Billing, D. G. Synthesis, Characterization and Phase Transitions of the Inorganic-Organic Layered Perovskite-Type Hybrids [(CnH2n+1NH3)2PbI4], n= 7, 8, 9 and 10. Dalton Trans. 2012, 41, 1146−1157. (31) Billing, D. G.; Lemmerer, A. Synthesis, Characterization and Phase Transitions in the Inorganic-Organic Layered Perovskite-Type Hybrids [(CnH2n+1NH3)2PbI4], n= 4, 5 and 6. Acta Crystallogr., Sect. B: Struct. Sci. 2007, 63, 735−747. (32) Liao, W. Q.; Mei, G. Q.; Ye, H. Y.; Mei, Y. X.; Zhang, Y. Structural Phase Transitions of a Layered Organic−Inorganic Hybrid Compound: Tetra (cyclopentylammonium) Decachlorotricadmate (II),[C5H9NH3]4Cd3Cl10. Inorg. Chem. 2014, 53, 8913−8918. (33) Liao, W. Q.; Ye, H. Y.; Fu, D. W.; Li, P. F.; Chen, L. Z.; Zhang, Y. Temperature-Triggered Reversible Dielectric and Nonlinear Optical Switch Based on the One-Dimensional Organic−Inorganic Hybrid Phase Transition Compound [C6H11NH3]2CdCl4. Inorg. Chem. 2014, 53, 11146−11151. (34) Lv, X. H.; Liao, W. Q.; Wang, Z. X.; Li, P. F.; Mao, C. Y.; Ye, H. Y. Design and Prominent Dielectric Properties of a Layered PhaseTransition Crystal:(Cyclohexylmethylammonium)2CdCl4. Cryst. Growth Des. 2016, 16, 3912−3916. (35) Mao, C. Y.; Liao, W. Q.; Wang, Z. X.; Li, P. F.; Lv, X. H.; Ye, H. Y.; Zhang, Y. Structural Characterization, Phase Transition and Switchable Dielectric Behaviors in a New Zigzag Chain OrganicInorganic Hybrid Compound:[C3H7NH3]2SbI5. Dalton Trans. 2016, 45, 5229−5233. (36) Ye, H. Y.; Zhou, Q.; Niu, X.; Liao, W. Q.; Fu, D. W.; Zhang, Y.; You, Y. M.; Wang, J.; Chen, Z. N.; Xiong, R.-G. High-Temperature Ferroelectricity and Photoluminescence in a Hybrid Organic− Inorganic Compound:(3-Pyrrolinium) MnCl3. J. Am. Chem. Soc. 2015, 137, 13148−13154. (37) Xu, W. J.; He, C. T.; Ji, C. M.; Chen, S. L.; Huang, R. K.; Lin, R. B.; Xue, W.; Luo, J. H.; Zhang, W. X.; Chen, X. M. Molecular Dynamics of Flexible Polar Cations in a Variable Confined Space: Toward Exceptional Two-Step Nonlinear Optical Switches. Adv. Mater. 2016, 28, 5886−5890.

Foundation of Graduate School of Southeast University (YBJJ1629).

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REFERENCES

(1) Champagne, B.; Plaquet, A.; Pozzo, J. L.; Rodriguez, V.; Castet, F. Nonlinear Optical Molecular Switches as Selective Cation Sensors. J. Am. Chem. Soc. 2012, 134, 8101−8103. (2) Feringa, B. L.; van Delden, R. A.; Koumura, N.; Geertsema, E. M. Chiroptical Molecular Switches. Chem. Rev. 2000, 100, 1789−1816. (3) Raymo, F. M. Digital Processing and Communication with Molecular Switches. Adv. Mater. 2002, 14, 401−414. (4) Salinga, M.; Wuttig, M. Phase-Change Memories on a Diet. Science 2011, 332, 543−544. (5) Zhang, W.; Xiong, R.-G. Ferroelectric Metal−Organic Frameworks. Chem. Rev. 2012, 112, 1163−1195. (6) Shi, P. P.; Tang, Y. Y.; Li, P. F.; Liao, W. Q.; Wang, Z. X.; Ye, Q.; Xiong, R.-G. Symmetry Breaking in Molecular Ferroelectrics. Chem. Soc. Rev. 2016, 45, 3811−3827. (7) Price, S. L. Predicting Crystal Structures of Organic Compounds. Chem. Soc. Rev. 2014, 43, 2098−2111. (8) Morita, Y.; Murata, T.; Nakasuji, K. Cooperation of HydrogenBond and Charge-Transfer Interactions in Molecular Complexes in the Solid State. Bull. Chem. Soc. Jpn. 2013, 86, 183−197. (9) Grabowski, Z. R.; Rotkiewicz, K.; Rettig, W. Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures. Chem. Rev. 2003, 103, 3899−4032. (10) Sato, O. Dynamic Molecular Crystals with Switchable Physical Properties. Nat. Chem. 2016, 8, 644−656. (11) Zhang, W.; Ye, H. Y.; Graf, R.; Spiess, H. W.; Yao, Y. F.; Zhu, R. Q.; Xiong, R.-G. Tunable and Switchable Dielectric Constant in an Amphidynamic Crystal. J. Am. Chem. Soc. 2013, 135, 5230−5233. (12) Liu, Y. L.; Wang, Y. F.; Zhang, W. Switchable Dielectric Constant in an Inclusion Compound Bis (thiourea) Imidazolium Chloride. CrystEngComm 2016, 18, 1958−1963. (13) Liu, Y. L.; Wang, Z.; Han, X. B.; Sun, Y. L.; Pryor, D. E. Orientational Ordering of Guest Induced Structural Phase Transition Coupled with Switchable Dielectric Properties in a Host−Guest Crystal: Bis (thiourea) Thiazolium Chloride. RSC Adv. 2016, 6, 108028−108033. (14) Chen, T. L.; Zhou, Y. L.; Sun, Z. H.; Zhang, S. Q.; Zhao, S. G.; Tang, Y. Y.; Ji, C. M.; Luo, J. H. ABX3-Type Organic−Inorganic Hybrid Phase Transition Material: 1-Pentyl-3-methylimidazolium Tribromoplumbate. Inorg. Chem. 2015, 54, 7136−7138. (15) Ji, C. M.; Sun, Z. H.; Zhang, S. Q.; Zhao, S. G.; Chen, T. L.; Tang, Y. Y.; Luo, J. H. A Host−Guest Inclusion Compound for Reversible Switching of Quadratic Nonlinear Optical Properties. Chem. Commun. 2015, 51, 2298−2300. (16) Sun, Z. H.; Chen, T. L.; Liu, X. T.; Hong, M. C.; Luo, J. H. Plastic Transition to Switch Nonlinear Optical Properties Showing the Record High Contrast in a Single-Component Molecular Crystal. J. Am. Chem. Soc. 2015, 137, 15660−15663. (17) Sun, Z. H.; Tang, Y. Y.; Zhang, S. Q.; Ji, C. M.; Chen, T. L.; Hong, M. C.; Luo, J. H. Ultrahigh Pyroelectric Figures of Merit Associated with Distinct Bistable Dielectric Phase Transition in a New Molecular Compound: Di-n-Butylaminium Trifluoroacetate. Adv. Mater. 2015, 27, 4795−4801. (18) Xu, W. J.; Chen, S. L.; Hu, Z. T.; Lin, R. B.; Su, Y. J.; Zhang, W. X.; Chen, X. M. The Cation-Dependent Structural Phase Transition and Dielectric Response in a Family of Cyano-Bridged Perovskite-Like Coordination Polymers. Dalton Trans. 2016, 45, 4224−4229. (19) Mitzi, D. B. Synthesis, Structure, and Properties of OrganicInorganic Perovskites and Related Materials. Prog. Inorg. Chem. 1999, 48, 1. (20) Stranks, S. D.; Eperon, G. E.; Grancini, G.; Menelaou, C.; Alcocer, M. J. P.; Leijtens, T.; Herz, L. M.; Petrozza, A.; Snaith, H. J. Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an Organometal Trihalide Perovskite Absorber. Science 2013, 342, 341− 344. 7063

DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064

Article

Inorganic Chemistry (38) Zhang, W.; Cai, Y.; Xiong, R. G.; Yoshikawa, H.; Awaga, K. Exceptional Dielectric Phase Transitions in a Perovskite-Type Cage Compound. Angew. Chem., Int. Ed. 2010, 49, 6608−6610. (39) Xu, W. J.; Xie, K. P.; Xiao, Z. F.; Zhang, W. X.; Chen, X. M. Controlling Two-Step Phase Transitions and Dielectric Responses by A-Site Cations in Two Perovskite-like Coordination Polymers. Cryst. Growth Des. 2016, 16, 7212−7217. (40) Xu, W. J.; Du, Z. Y.; Zhang, W. X.; Chen, X. M. Structural Phase Transitions in Perovskite Compounds Based on Diatomic or Multiatomic Bridges. CrystEngComm 2016, 18, 7915−7928. (41) Liao, W. Q.; Ye, H. Y.; Zhang, Y.; Xiong, R.-G. Phase Ttransitions and Dielectric Properties of a Hexagonal ABX3 Perovskite-Type Organic-Inorganic Hybrid Compound:[C3H4NS][CdBr3]. Dalton Trans. 2015, 44, 10614−10620. (42) Wang, Z. X.; Liao, W. Q.; Ye, H. Y.; Zhang, Y. Sequential Structural Transitions with Distinct Dielectric Responses in a Layered Perovskite Organic-Inorganic Hybrid Material:[C4H9N]2[PbBr4]. Dalton Trans. 2015, 44, 20406−20412. (43) Kundys, B.; Lappas, A.; Viret, M.; Kapustianyk, V.; Rudyk, V.; Semak, S.; Simon, C.; Bakaimi, I. Multiferroicity and Hydrogen−Bond Ordering in (C2H5NH3)2CuCl4 Featuring Dominant Ferromagnetic Interactions. Phys. Rev. B: Condens. Matter Mater. Phys. 2010, 81, 224434. (44) Polyakov, A. O.; Arkenbout, A. H.; Baas, J.; Blake, G. R.; Meetsma, A.; Caretta, A.; van Loosdrecht, P. H. M.; Palstra, T. T. M. Coexisting Ferromagnetic and Ferroelectric Order in a CuCl4-based Organic−Inorganic Hybrid. Chem. Mater. 2012, 24, 133−139. (45) Huang, B.; Wang, B. Y.; Du, Z. Y.; Xue, W.; Xu, W. J.; Su, Y. J.; Zhang, W. X.; Zeng, M. H.; Chen, X. M. Importing Spontaneous Polarization into a Heisenberg Ferromagnet for a Potential SinglePhase Multiferroic. J. Mater. Chem. C 2016, 4, 8704−8710. (46) Liao, W. Q.; Zhang, Y.; Hu, C. L.; Mao, J. G.; Ye, H. Y.; Li, P. F.; Huang, S. D.; Xiong, R.-G. A Lead-Halide Perovskite Molecular Ferroelectric Semiconductor. Nat. Commun. 2015, 6, 7338. (47) Ye, H. Y.; Liao, W. Q.; Hu, C. L.; Zhang, Y.; You, Y. M.; Mao, J. G.; Li, P. F.; Xiong, R.-G. Bandgap Engineering of Lead-Halide Perovskite-Type Ferroelectrics. Adv. Mater. 2016, 28, 2579−2586. (48) Wang, Z. X.; Li, P. F.; Liao, W. Q.; Tang, Y. Y.; Ye, H. Y.; Zhang, Y. Structure-Triggered High Quantum Yield Luminescence and Switchable Dielectric Properties in Manganese(II) Based Hybrid Compounds. Chem. - Asian J. 2016, 11, 981−985. (49) Wang, G. E.; Xu, G.; Liu, B. W.; Wang, M. S.; Yao, M. S.; Guo, G. C. Semiconductive Nanotube Array Constructed from Giant [PbII18I54(I2)9] Wheel Clusters. Angew. Chem., Int. Ed. 2016, 55, 514− 518. (50) Jaeger, G. The Ehrenfest Classification of Phase Transitions: Introduction and Evolution. Arch. Hist. Exact Sci. 1998, 53, 51−81. (51) Swainson, I.; Hammond, R.; Cockcroft, J.; Weir, R. Apparently Continuous Isosymmetric Transition in Ammonium Hexafluorophosphate NH4PF6. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 174109. (52) Arvanitidis, J.; Papagelis, K.; Margadonna, S.; Prassides, K.; Fitch, A. N. Temperature-Induced Valence Transition and Associated Lattice Collapse in Samarium Fulleride. Nature 2003, 425, 599−602. (53) Apih, T.; Gregorovič, A.; Ž agar, V.; Seliger, J. Nuclear Quadrupole Resonance Study of Proton and Deuteron Migration in Short Strong Hydrogen Bonds Formed in Molecular Complex 3,5Dinitrobenzoic Acid−Nicotinic Acid and in Deuterated 3,5-Pyridinedicarboxylic Acid. J. Phys. Chem. C 2016, 120, 9992−10000.

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DOI: 10.1021/acs.inorgchem.7b00662 Inorg. Chem. 2017, 56, 7058−7064