Temperature-Induced Structural Phase Transitions in Two New

Subscriber access provided by University of Kansas Libraries

Article

Temperature-induced structural phase transitions in two new post-perovskite coordination polymers Sha-Sha Wang, Rui-Kang Huang, Xiao-Xian Chen, Wei-Jian Xu, Wei-Xiong Zhang, and Xiao-Ming Chen Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.8b01615 • Publication Date (Web): 02 Jan 2019 Downloaded from http://pubs.acs.org on January 2, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design

Temperature-induced structural phase transitions in two new post-perovskite coordination polymers Sha-Sha Wang, Rui-Kang Huang, Xiao-Xian Chen, Wei-Jian Xu, Wei-Xiong Zhang,* and XiaoMing Chen* *MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun YatSen University, Guangzhou, 510275, P. R. China ABSTRACT. We presented two new ABX3 post-perovskite coordination polymers, (C5H13NCl)[M(dca)3] (dca = N(CN)2−, M = Mn2+ for 1 and Cd2+ for 2), as well as their phase transition behaviors disclosed by using differential scanning calorimetry measurements, variabletemperature single-crystal X-ray analyses, dielectric measurements, and Hirshfeld surface analyses. Both of 1 and 2 have same structure (Cmcm) at room temperature, in which their A-site organic cations are 4-fold disordered about two mirror planes, and undergo order-disorder phase transition mainly caused by the freezing of A-site cations upon cooling. The different metal ions endow them distinct structural flexibility, resulting in different phase transition behaviors and dielectric responses, i.e., the smaller and coordinatively-rigid Mn2+ ion results in two-step Cmcm (Z = 4) ↔ Pbcm (Z = 4) ↔ Pbca (Z = 8) transitions accompanying with obvious dielectric relaxation, whereas the larger and coordinatively-flexible Cd2+ ion results in one-step Cmcm (Z = 4) ↔ Pbca (Z = 16) transition accompanying with a sharp dielectric switching. This study well demonstrates the tunability of post-perovskite, as a new kind of host-guest model, for modulating the phase transition and relevant switching physical properties. Keywords: post-perovskite, phase transition, order-disorder, Hirshfeld surface analyses 1 ACS Paragon Plus Environment

Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 20

INTRODUCTION The phase-transition materials are of particular importance owing to their applications as diverse fundamental materials in manifold fields such as sensors, switches, and information storages.1-4 As an important supplement of inorganic ones, molecule-based phase-transition materials have attracted increasing attentions in virtue of their light weight, mechanical flexibility, environmentally benign synthesis.2,

5-8

In particular, the ABX3-type molecular

perovskites,9-18 which topologically mimic the ABO3-type inorganic perovskite structure by using diverse molecular components, as an important host-guest model, have make great contributions to recent developments of advanced phase-transition materials,19 such as practically-desirable multi-axial ferroelectrics achieved by significant symmetry breaking via traditional order-disorder mechanism16, 20 or unprecedented bond-switching mechanism,21 and highly-integrated multi-functional switches achieved by of rationally controlling the molecular dynamics of polar guest cations.22-23 According to the linkage of the BX6 octahedra, the ABX3-type perovskites could be classified as three typical subclasses: cubic, hexagonal, and post perovskite. The cubic and hexagonal perovskites are commonly observed, in which the BX6 octahedra share vertexes and faces to form host frameworks and chains,24-25 respectively, whereas the post-perovskite is much rare and relatively complex, in which the BX6 octahedra share edges and corners along the aand c-axes, respectively, to form (4,4)-network layers interleaved by the A-site cations (Figure S3).26-28 Such post-perovskite structure provides a distinct host-guest model, compared with those in the cubic and hexagonal ones, in which the layers define the layer-confined spaces to regulate the molecular dynamics of A-site guests, and hence could give rise to unique phase transition behaviors together with the relevant switchable physical properties. However, only a 2 ACS Paragon Plus Environment

Page 3 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


few of molecule-based compounds possessing post-perovskite structure were sporadically observed to date,29-35 which were constructed by singular/mixing multi-atomic bridges including HCOO−, SCN− and N(CN)2− (dca), and only one of them was documented exhibiting structural phase transitions very recently.35 In this sense, to assemble new molecular post-perovskites and endow them abundant phase transitions, as an important branch of molecular perovskites, is explicitly meaningful in the field of phase-transition materials. Differing from the previously-employed bulk and relatively-rigid cations, we focused on employing relatively-long and flexible cations to act as the A-site guests for endowing the postperovskites to reveal order-disorder phase transitions. With its V-shaped coordination configuration, the dca anion is a suitable bridge to construct cubic perovskites36-39 and postperovskites31-35 with large voids to accommodate larger and flexible cations. In our ongoing attempts on construction of dca-bridged post-perovskites by employing diverse flexible cations, we successfully obtained two new molecular post-perovskites, (chlorocholine)[M(dca)3] (M = Mn2+ for 1, and Cd2+ for 2), in which chlorocholine acts as A-site cation. Herein, we present their structures, distinct phase transition behaviors, as well as the switchable dielectric responses, as disclosed by using combined techniques of differential scanning calorimetry (DSC) measurements, variable-temperature single-crystal X-ray structural analyses, dielectric measurements and Hirshfeld surface analyses. EXPERIMENTAL SECTION Materials and Methods. All reagents and solvents were commercially available and were used without further purification. Elemental (C, H, and N) analyses were performed on a Perkin Elmer Vario EL elemental analyzer with as-synthesized samples. Variable-temperature powder X-ray

3 ACS Paragon Plus Environment


Page 4 of 20

diffraction (PXRD) patterns (Cu Kα, λ = 1.54056 Å) were collected on Bruker Advance D8 DAVANCI diffractometer. Thermogravimetric analyses (TGA) were carried out on a TG 209 F3 Tarsus at a heating rate of 10 K min−1 under a nitrogen atmosphere. Differential scanning calorimetry (DSC) measurements were performed by heating and cooling the powder samples at a rate of 10 K min−1 on a TA DSC Q2000 instrument under a nitrogen atmosphere in aluminum crucibles. For powder-pressed pellet samples, the dielectric measurements were measured on Tonghui TH2828A LCR meter in a Mercury iTC cryogenic environment controller from Oxford Instruments at a rate of approximately 2 K min−1 in the temperature range of 80–300 K. Synthesis of (C5H13NCl)[Mn(dca)3] (1). A mixture of chlorocholine chloride (158 mg, 1 mmol), Na(dca) (267 mg, 3 mmol) and 50 wt% Mn(NO3)2 aqueous solution (0.24 mL, 1 mmol) was added into water (10 mL) and then ultrasound for 10 min. The filtered solution was placed in a desiccator and evaporated slowly at room temperature. After about one week, colorless blockshaped crystals of 1 were obtained from solution before the solvent completely evaporated. Elemental analysis: C11H13N10ClMn (1): calcd. C: 35.2%, H: 3.5%, N: 37.3%; found C: 35.7%, H: 3.2%, N: 37.0%. Synthesis of (C5H13NCl)[Cd(dca)3] (2). 2 was synthesized by a similar procedure for 1, except for using Cd(NO3)2·4H2O (0.308 mg, 1 mmol) instead of 50 wt% Mn(NO3)2 aqueous solution as the reactant. Elemental analysis: C11H13N10CdCl (2): calcd. C: 30.5%, H: 3.0%, N: 32.3%; found C: 30.6%, H: 2.9%, N: 32.2%. X-ray Single-crystal Diffraction Analyses. The X-ray diffraction measurements for 1 were performed in a nitrogen atmosphere on a single crystal in BL17B beamline of National Center for Protein Sciences Shanghai and Shanghai Synchrotron Radiation Facility (λ = 0.65253 Å).


Page 5 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Data processing was carried out by using the HKL3000 program. The temperature swept from 230 to 150 K in a very slow rate of 0.4 K/min, meanwhile the diffraction images were continuously collected with an exposing time of 6 s/frame by continuously rotating ϕ angle in a rate of 5°/frame. The data sets for 1_HTP and 1_LTP were extracted from the first and the last 36 frames collected near the temperature of 230 and 150 K, respectively. For 1_ITP, the continuous dozens of frames collected in the temperature range where pure 1_ITP could possibly exist were submitted to index, and finally we found continuous 13 frames could be well indexed and then to yield a reasonable structure corresponding to 1_ITP, which only spent 78 seconds spanning a quite narrow temperature range of about 0.5 K. Such in-situ single-crystal Xray diffraction analyses by sweeping temperature with a slow rate is similar to the commonlyemployed in-situ powder diffraction analyses.40-42 For 2, the diffraction data were collected at 275 K and 189 K on a Rigaku XtaLAB P300DS single-crystal diffractometer by using graphite monochromated Cu Kα (λ = 1.54056 Å) radiation. Absorption corrections were applied by using the multi-scan program CrysAlisPro. All the structures were solved by the direct methods and refined by the full-matrix least-squares technique with the SHELX program package. Anisotropic thermal parameters were applied to all non-hydrogen atoms. The hydrogen atoms were generated geometrically. Crystal data as well as details of data collection and refinements for 1 and 2 are summarized in Table 1. CCDC 1874906, 1874907, 1874908, 1874909, 1874910 contain the supplementary crystallographic data for 1 and 2.



Page 6 of 20

Table 1. Crystallographic data and structural refinements for 1 and 2 at different temperatures.

Complex

(C5H13NCl)[Mn(dca)3] (1)

(C5H13NCl)[Cd(dca)3] (2)

Temperature / K

230(2)

198(2)

150(2)

275(2)

189(2)

Phase

1_HTP

1_ITP

1_LTP

2_HTP

2_LTP

Crystal system

orthorhombic

orthorhombic

orthorhombic

orthorhombic

orthorhombic

Space group

Cmcm

Pbcm

Pbca

Cmcm

Pbca

a/Å

7.5835(4)

7.568(2)

15.118(3)

7.7090(2)

15.3691(3)

b/Å

13.430(1)

13.218(3)

13.160(3)

13.2746(3)

26.0601(4)

c/Å

16.7249(9)

16.636(3)

16.600(3)

16.9083(4)

16.8217(3)

V / Å3

1703.4(2)

1664.2(6)

3302.6(1)

1730.29(7)

6737.4(2)

Z

4

4

8

4

16

Rint

0.0629

0.0942

0.0732

0.0678

0.0816

R1 [I > 2σ(I)]

0.0394

0.0761

0.0617

0.0423

0.0473

wR2 [I > 2σ(I)]

0.0955

0.1757

0.1564

0.1211

0.1326

GOF

1.196

1.107

1.036

1.186

1.020

Completeness (%)

98.1

96.7

99.8

97.9

99.9

CCDC numbers

1874906

1874907

1874908

1874909

1874910

a

R1 = Fo‐Fc/Fo, bwR2 = {w[(Fo)2‐(Fc)2]2/w[(Fo)2]2}1/2

RESULTS AND DISCUSSION Thermal Analyses. The TGA measurements indicated that, 1 and 2 could stable up to 485 K under a nitrogen atmosphere (Figure S2). Phase transitions were detected by DSC in the temperature range of 80–453 K. As shown in Figure 1a, two relatively small and obtuse thermal anomalies were observed at 206.1/204.8 K (T1) and 195.6/194.4 K (T1′), respectively, during the heating-cooling cycles, indicating reversible two-step phase transitions for 1. One relatively-


Page 7 of 20

sharp thermal anomaly peak was observed at 210.8/209.6 K (T2) during the heating-cooling cycles for 2, indicating a reversible single-step phase transition (Figure 1b). Such distinct thermal anomalies implicates that 1 and 2 have rather different phase transition behaviors. For convenience, we name the phases of 1 above T1 as 1_HTP, between T1 and T1′ as 1_ITP, and below T1′ as 1_LTP, while the phases of 2 above and below T2 as 2_HTP and 2_LTP,

-1

respectively.

-1

Heat Flow/ mW mg Heat Flow/ mW mg

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1

(a) cooling heating

0

-1 3

1_LTP

1_ITP

1_HTP

(b)

0

2_LTP

2_HTP

-3 150

200 Temperature / K

250

Figure 1. DSC curves of 1 (a) and 2 (b) during the heating-cooling cycles.

Crystal Structures and Structural Phase Transitions. Variable-temperature X-ray singlecrystal diffraction analyses were performed to investigate structural transitions for 1 and 2. As shown in Table 1 and Figures 2 and 3, in both of 1 and 2, each MII ion is coordinated with six N atoms from six dca ligands, and each dca ligand acts as a bridge linking two MII ions by two



Page 8 of 20

terminal N atoms. Each MII ion links two MII ions along the a-axis via two double-bridges, respectively, meanwhile links another two MII ions along the c-axis via two single-bridges, respectively. Therefore, by regarding a M(dca)6 coordination unit as a BX6 octahedron and the chlorocholine as A-site cations, the entire structures of both 1 and 2 could be topologically regarded as post-perovskite structures, i.e., BX6 octahedra share the edges and corners along the a- and c-axes, respectively, forming the anionic layers interleaved by A-site cations.26-28 Both of 1_HTP and 2_HTP crystallize in the same centrosymmetric space group Cmcm (No. 63) with similar cell parameters. However, as disclosed by structural analyses and DSC measurements, 1 and 2 have different phase transition behaviors upon cooling. For 1, with decreasing temperature, it undergoes step-by-step phase transitions with the space group changing from Cmcm (No. 63) at 1_HTP to Pbcm (No. 57) at 1_ITP, and further to Pbca (No. 61) at 1_LTP. Such two-step phase transitions obey the group-subgroup relationship (Figure S6), and could be mainly ascribed to the two-step freezing of guest cations. In 1_HTP, the chlorocholine cations locate at two mirror planes perpendicular to the a- and c-axes, respectively, and thus, are 4-fold disordered about these two mirror planes (Figure 2a). With cooling, they become 2-fold disordered about the minor planes perpendicular to the c-axis in 1_ITP (Figure 2b), and eventually become ordered in 1_LTP (Figure 2c). As a result, 1_ITP become P-lattice with similar cell paremeters as 1_HTP, while 1_LTP has a doubled unit cell compared with 1_ITP, as the a-axis length is doubled from 7.568(2) Å at 1_ITP to 15.118(3) Å at 1_LTP. In contrast, the dca ligands acting as the double-bridges reveal noticeable disorder over two sites in these three phases of 1, implying that they make minor contribution on triggering the phase transitions.


Page 9 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 2. Crystal structures of 1 at different phases.

Figure 3. Crystal structures of 2 at different phases. For 2, upon cooling, one-step phase transition occurs with the space group changing from Cmcm (No. 63) at 2_HTP to Pbca (No. 61) at 2_LTP. All the guest cations are 4-fold disordered in 2_HTP, same with those in 1_HTP, and then become ordered in 2_LTP, similar to those in 1_LTP. It should be pointed out that, the asymmetric unit in 2_LTP is double than that in 1_LTP with two crystallographically-independent guest cations (cation A and B, respectively), as the b-axis length [26.0601(4) Å] in 2_LTP is twice as long as that in 1_LTP [b = 13.160(3) Å]. As a result, the Z value is 16 and 8 for 2_LTP and 1_LTP, respectively, indicating 2_LTP has relatively-lower symmetry than 1_LTP. Such distinct difference is also reflected in the



Page 10 of 20

arrangement of guest cations and packing mode of host layers. As shown in the overlay structures (Figure S4), the arrangements of the half of guest cations at 2_LTP and 1_LTP are different. Besides, as shown in Figure S5a, at 1_LTP phase, all the host sheets are the same and constructed by Mn1 and dca ligands (Figure S5a), while at 2_LTP phase, there are two different types of layers, of which one is constructed by Cd3 and dca ligands, and the other one is constructed by two crystallographically-independent metal cations Cd1, Cd2, and dca ligands (Figure S5b).

Figure 4. (a) Hirshfeld surfaces mapped with dnorm over the range −0.18 (red) to 1.00 (blue) for the guest cation in 1_LTP, (b) Percentage contributions to the Hirshfeld surface area for the various close intermolecular contacts for 1 and 2 at different phases, and fingerprint plots for the crystallographically-independent guest cations in different phases of 1 (c) and 2 (d).


Page 11 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Hirshfeld surfaces analyses. To further understand the changes in the intermolecular interactions accompanied by phase transitions, the Hirshfeld surfaces analyses were carried out for the guest cations in 1 and 2. The Hirshfeld surface is defined by the molecule and the proximity of its nearest neighbors, and could provide an unbiased picture of all close contacts to encodes information about intermolecular interactions.43 As shown in Figure 4b, for all cations in 1 and 2, the H···C and H···N contacts are associated with nearly 74% of the surface area, making the major contribution to the host-guest interactions, while the H···Cl and Cl···H contacts are associated with about 19% of the surface area, making the main contribution to the guest-guest interactions. Taking the ordered guest cation in 1_LTP for example, as indicated by the red spots in its Hirshfeld surface mapped with normalized contact distance, dnorm (Figure 4a), in which the contracts shorter and longer than van der Waals separations show up as red and blue spots, respectively, the H11···C2 (2.523 Å), H7···N2 (2.539 Å) and H10···C1 (2.563 Å) contacts dominate the intermolecular interactions, probably owing to the electrostatically-attractive nature between the organic cations and anionic dca bridges. In contrast, the Cl atom in the organic cation trends to far away from the dca anionic bridges, as implicated by the blue and white regions in the nearby surface of Cl atom. The differences of fingerprint plots (Figure 4c and 4d) for the guest cations encode the changes of the intermolecular interactions accompanying with phase transitions. These plots are two-dimensional histograms of the relative frequency of points with individual (di, de) pairs on each point of the Hirshfeld surfaces, where di and de refer to the distances from surface to the nearest nucleus inside and outside the surface, respectively.43 Pixels associated with each pair of distances are colored from blue (for very low frequency of occurrence), through green, to yellow and red (for highest frequency). The distinct regions in Figure 4c and 4d are resulting from large



Page 12 of 20

numbers of close contacts around (di, de) ≈ (1.0~1.6 Å, 1.5~2.2 Å), and associated with H···C or H···N contacts (Figure S7). Moreover, the distribution of yellow or red areas for 1_HTP and 2_HTP represents significantly-dispersed features than those in the other phases, well reflecting the highly-disordered state for their guest cations. In detail, such changes on the intermolecular interactions are closely associated with the competition of the host-guest interactions as well as the resulted order-disorder transitions. Taking 1 as example, for each guest cation, there are abundant H···C and H···N short contacts could be formed between the H atoms from guest cations and the C/N atoms from dca anions, but these short contacts could not be fulfilled at the same time for a specified conformation of guest cation. For instance, as shown in Hirshfeld surfaces mapped with dnorm (Figure S8), there are four H···C short contacts could be formed between the H atom from –CH2– moiety linking Cl atom and four C atoms from two single-bridging dca anions for each guest cation, but only one of them, i.e., H11···C2 short contact, could be formed for a frozen guest cation in 1_LTP (Figure 4a). When the temperature increases, the energy barrier for changing conformation of guest cations could be overcome, hence allowing the guest cations to dynamically fulfill two H···C short contacts in 1_ITP and four short contacts in 1_HTP. It is obvious that all the other guest-framework short contacts reveal similar temperature-dependent behaviors, jointly making contribution to the order-disorder phase transition for both 1 and 2. Dielectric Properties. The temperature-dependent permittivities (e = e′ + ie′′) were measured on the powder-pressed pellets for 1 and 2. Basically, as shown in Figures 5 and 6, both 1 and 2 exhibit step-like dielectric anomalies in the vicinity of phase-transition temperatures, consisting with the freezing of the polar guest cations upon cooling. However, the real part (e′) and


Page 13 of 20

imaginary part (e′′) of dielectric permittivity are obviously frequency-dependent in the vicinity of phase-transition temperatures for 1. This extra dielectric relaxation phenomenon well explains the small and obtuse thermal anomalies disclosed in 1 by DSC measurement, which estimated the entropy-changes (DS) of 0.88 and 2.49 J K-1 mol-1 for the phase transitions 1_HTPÆ1_ITP and 1_ITPÆ1_LTP, respectively, both are smaller than the expected DS values (5.8 J K-1 mol-1) for 2-fold order-disorder transition according to the Boltzmann equation, DS = RlnN, where R is the gas constant and N is the ratio of the numbers of respective distinguishable orientations in both phases. These small observed DS values implicate that noticeable residual entropies are left out owing to the relaxation processing.44-45 In contrast, e′ of 2 shows a relatively rapid step-like anomaly changing from 3.0 to 2.8 in vicinity of phase transition temperature, well in agreement with the sharp peak thermal anomaly detected by DSC, where the estimated DS value (11.8 J K-1 mol-1) is close to the expected one (11.5 J K-1 mol-1) for the 4-fold order-disorder transition.46-48

e¢

3.4 3.2

(a)

800 Hz 1000 Hz 2.5 KHz 5 KHz 8 KHz 10 KHz 25 KHz

3.0

e¢¢

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(b)

0.2

0.0 150

180

210 240 Temperature / K

270

Figure 5. The real part (a) and imaginary part (b) of dielectric permittivity for 1 measured at different frequencies in a cooling mode.



3.1 3.0

e¢

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 20

800 Hz 1000 Hz 2.5 KHz 5 KHz 8 KHz 10 KHz 25 KHz

2.9 2.8 120

160 200 Temperature / K

240

Figure 6. The dielectric constant for 2 measured at different frequencies in a cooling mode.

CONCLUSIONS In summary, we successfully obtained two new post-perovskite coordination polymers, i.e., 1 and 2, and disclosed their distinct phase transition behaviors by using combined techniques including DSC measurements, variable-temperature single-crystal X-ray analyses, dielectric measurements, and Hirshfeld surface analyses. Both of 1_HTP and 2_HTP crystallize in same space group Cmcm with similar cell parameters, in which their A-site cations are 4-fold disordered about two mirror planes. Upon cooling, 1 undergoes two-step phase transitions from 1_HTP (Cmcm) to 1_ITP (Pbcm) with similar cell parameters and 2-fold-disordered guest cations, and then further to 1_LTP (Pbca) with a doubled a-axis length and fully-ordered guest cations. Whereas 2 only undergoes one-step phase transition from 2_HTP (Cmcm) to 2_LTP (Pbca) with both doubled a- and b-axes lengths and fully-ordered guest cations. In addition, the two-step phase transitions in 1 result in a gentle dielectric switching together with dielectric relaxation and smaller latent heats, whereas the one-step phase transition in 2 gives a sharp 14 ACS Paragon Plus Environment

Page 15 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


dielectric switching and a larger latent heat. Such distinct phase transition behaviors in 1 and 2 well demonstrated the important roles played by the different B-site coordination metal cations. The larger and coordinatively-flexible Cd2+ ion could endow 2 relatively-flexible layers to interplay with the freezing dynamics of A-site cations, and hence, results in a sharp one-step phase transition with more significant symmerty breaking. This study not only presents two new dca-bridged post-perovskites with abundant phase transitions, but also indicates the tunability of post-perovskite, as a new kind of host-guest model, by diverse molecular components for modulating the phase transition and relevant switching physical properties, opening up a broad prospect for further research on phase transition materials. ASSOCIATED CONTENT Supporting Information. The supporting information is available free of charge on ACS Publications Website at DOI: 10.1021/acs.cgd.xxxxxxx. The following files are available free of charge. Thermogravimetric analysis, PXRD patterns, and details of other characterizations. (PDF) AUTHOR INFORMATION Corresponding Authors *(W.-X.Z.) E-mail: [email protected] *(X.-M.C.) E-mail: [email protected] Notes The authors declare no competing financial interest.



Page 16 of 20

ACKNOWLEDGMENT This work was supported by the NSFC (21722107, 21671202 and 21821003), Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01C161). We thank the staffs of BL17B beamlines at National Center for Protein Sciences Shanghai and Shanghai Synchrotron Radiation Facility, Shanghai, People's Republic of China, for assistance during data collection. DEDICATION Dedicated to Professor Xin-Tao Wu on the occasion of his 80th birthday.

REFERENCES (1) 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. (2) Sato, O., Dynamic molecular crystals with switchable physical properties. Nat. Chem. 2016, 8, 644-656. (3) Du, Z. Y.; Xu, T. T.; Huang, B.; Su, Y. J.; Xue, W.; He, C. T.; Zhang, W. X.; Chen, X. M., Switchable Guest Molecular Dynamics in a Perovskite-Like Coordination Polymer toward Sensitive Thermoresponsive Dielectric Materials. Angew. Chem., Int. Ed. 2015, 54, 914-918. (4) Liu, J.-Y.; Zhang, S.-Y.; Zeng, Y.; Shu, X.; Du, Z.-Y.; He, C.-T.; Zhang, W.-X.; Chen, X.-M., Molecular Dynamics, Phase Transition and Frequency-Tuned Dielectric Switch of an Ionic CoCrystal. Angew. Chem., Int. Ed. 2018, 130, 8164-8168. (5) Martin, L. W.; Rappe, A. M., Thin-film ferroelectric materials and their applications. Nat. Rev. Mater. 2016, 2, 16087. (6) Huang, B.; Zhang, J.-Y.; Huang, R.-K.; Chen, M.-K.; Xue, W.; Zhang, W.-X.; Zeng, M.-H.; Chen, X.-M., Spin-reorientation-induced magnetodielectric coupling effects in two layered perovskite magnets. Chem. Sci. 2018, 9, 7413-7418. (7) Huang, B.; Sun, L. Y.; Wang, S. S.; Zhang, J. Y.; Ji, C. M.; Luo, J. H.; Zhang, W. X.; Chen, X. M., A near-room-temperature organic-inorganic hybrid ferroelectric: [C6H5CH2CH2NH3]2[CdI4]. Chem. Commun. 2017, 53, 5764-5766. (8) 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 single-phase multiferroic. J. Mater. Chem. C 2016, 4, 8704-8710. (9) Liao, W. Q.; Tang, Y. Y.; Li, P. F.; You, Y. M.; Xiong, R. G., Large Piezoelectric Effect in a Lead-Free Molecular Ferroelectric Thin Film. J. Am. Chem. Soc. 2017, 139, 18071-18077. (10) You, Y.-M.; Liao, W.-Q.; Zhao, D.; Ye, H.-Y.; Zhang, Y.; Zhou, Q.; Niu, X.; Wang, J.; Li, P.-F.; Fu, D.-W.; Wang, Z.; Gao, S.; Yang, K.; Liu, J.-M.; Li, J.; Yan, Y.; Xiong, R.-G., An


Page 17 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


organic-inorganic perovskite ferroelectric with large piezoelectric response. Science 2017, 357, 306-309. (11) Liao, W. Q.; Tang, Y. Y.; Li, P. F.; You, Y. M.; Xiong, R. G., The Competitive Halogen Bond in the Molecular Ferroelectric with Large Piezoelectric Response. J. Am. Chem. Soc. 2018, 140, 3975-3980. (12) Pan, Q.; Liu, Z.-B.; Tang, Y.-Y.; Li, P.-F.; Ma, R.-W.; Wei, R.-Y.; Zhang, Y.; You, Y.-M.; Ye, H.-Y.; Xiong, R.-G., A Three-Dimensional Molecular Perovskite Ferroelectric: (3Ammoniopyrrolidinium)RbBr3. J. Am. Chem. Soc. 2017, 139, 3954-3957. (13) Zhang, W. Y.; Tang, Y. Y.; Li, P. F.; Shi, P. P.; Liao, W. Q.; Fu, D. W.; Ye, H. Y.; Zhang, Y.; Xiong, R. G., Precise Molecular Design of High-Tc 3D Organic-Inorganic Perovskite Ferroelectric: [MeHdabco]RbI3 (MeHdabco = N-Methyl-1,4-diazoniabicyclo[2.2.2]octane). J. Am. Chem. Soc. 2017, 139, 10897-10902. (14) Li, P.-F.; Tang, Y.-Y.; Liao, W.-Q.; Shi, P.-P.; Hua, X.-N.; Zhang, Y.; Wei, Z.; Cai, H.; Xiong, R.-G., Solid Experimental Evidence for First Triboluminescent Anti-perovskite Ferroelectric: Tris(trimethylammonium) catena-Tri-μ-chloro-manganate(II) Tetrachloromanganate(II). Angew. Chem., Int. Ed. 2018, 57, 11939-11942. (15) Wei, Z.; Liao, W. Q.; Tang, Y. Y.; Li, P. F.; Shi, P. P.; Cai, H.; Xiong, R. G., Discovery of an Antiperovskite Ferroelectric in [(CH3)3NH]3(MnBr3)(MnBr4). J. Am. Chem. Soc. 2018, 140, 8110-8113. (16) Ye, H.-Y.; Tang, Y.-Y.; Li, P.-F.; Liao, W.-Q.; Gao, J.-X.; Hua, X.-N.; Cai, H.; Shi, P.-P.; You, Y.-M.; Xiong, R.-G., Metal-free three-dimensional perovskite ferroelectrics. Science 2018, 361, 151-155. (17) Chen, S.-L.; Yang, Z.-R.; Wang, B.-J.; Shang, Y.; Sun, L.-Y.; He, C.-T.; Zhou, H.-L.; Zhang, W.-X.; Chen, X.-M., Molecular perovskite high-energetic materials. Sci. China Mater. 2018, 61, 1123-1128. (18) Chen, S.-L.; Shang, Y.; He, C.-T.; Sun, L.-Y.; Ye, Z.-M.; Zhang, W.-X.; Chen, X.-M., Optimizing the oxygen balance by changing the A-site cations in molecular perovskite highenergetic materials. CrystEngComm 2018, 20, 7458-7463. (19) Li, W.; Wang, Z.; Deschler, F.; Gao, S.; Friend, R. H.; Cheetham, A. K., Chemically diverse and multifunctional hybrid organic–inorganic perovskites. Nat. Rev. Mater. 2017, 2, 16099. (20) Tang, Y. Y.; Li, P. F.; Liao, W. Q.; Shi, P. P.; You, Y. M.; Xiong, R. G., Multiaxial Molecular Ferroelectric Thin Films Bring Light to Practical Applications. J. Am. Chem. Soc. 2018, 140, 8051-8059. (21) Xu, W. J.; Li, P. F.; Tang, Y. Y.; Zhang, W. X.; Xiong, R. G.; Chen, X. M., A Molecular Perovskite with Switchable Coordination Bonds for High-Temperature Multiaxial Ferroelectrics. J. Am. Chem. Soc. 2017, 139, 6369-6375. (22) 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. (23) Guo, Q.; Zhang, W.-Y.; Ye, Q.; Fu, D.-W., The First Molecule-Based Blue-Light OpticalDielectric Switching Material in Both Hybrid Bulk Crystal and Flexible Thin Film Forms. Adv. Opt. Mater. 2017, 5, 1700743. (24) Ackerman, J. F.; Cole, G. M.; Holt, S. L., The physical properties of some transition metal compounds of the ABX3 type. Inorg. Chim. Acta 1974, 8, 323-343.



Page 18 of 20

(25) Mitzi, D. B., Templating and structural engineering in organic–inorganic perovskites. J. Chem. Soc., Dalton Trans. 2001, 0, 1-12. (26) Rodi, V. F.; Babel, D., Erdalkaliiridium(IV)-oxide: Kristallstruktur von CalrO3. Z. Anorg. Allg. Chem. 1965, 17-23. (27) Murakami, M.; Hirose, K.; Kawamura, K.; Sata, N.; Ohishi, Y., Post-Perovskite Phase Transition in MgSiO3. Science 2004, 304, 855-858. (28) Martin, C. D.; Chapman, K. W.; Chupas, P. J.; Prakapenka, V.; Lee, P. L.; Shastri, S. D.; Parise, J. B., Compression, thermal expansion, structure, and instability of CaIrO3, the structure model of MgSiO3 post-perovskite. Am. Mineral. 2007, 92, 1048-1053. (29) Zhang, B.; Zhang, Y.; Wang, Z.; Gao, Z.; Yang, D.; Wang, D.; Guo, Y.; Zhu, D., (BEDTTTF)2Cu2(HCOO)5: An Organic–Inorganic Hybrid Conducting Magnet. ChemistryOpen 2017, 6, 320-324. (30) Fleck, M., Thiocyanates of nickel and caesium: Cs2NiAg2(SCN)6·2H2O and CsNi(SCN)3. Acta Cryst. 2004, 60, i63-i65. (31) Raebiger, J. W.; Manson, J. L.; Sommer, R. D.; Geiser, U.; Rheingold, A. L.; Miller, J. S., 1-D and 2-D Homoleptic Dicyanamide Structures, [Ph4P]2{CoII[N(CN)2]4} and [Ph4P]{M[N(CN)2]3} (M =Mn, Co). Inorg. Chem. 2001, 40, 2578-2581. (32) Werff, P. M. v. d.; Batten, S. R.; Jensen, P.; Moubaraki, B.; Murray, K. S.; Tan, E. H.-K., Structure and magnetism of anionic dicyanamidometallate extended networks of types (Ph4As)[MII(dca)3] and (Ph4As)2[M2II(dca)6(H2O)]·H2O·xCH3OH, where dca = N(CN)2-, MII = Co, Ni. Polyhedron 2001, 20, 1129-1138. (33) Wang, H. T.; Zhou, L.; Wang, X. L., A two-dimensional anionic CdII polymer constructed through dicyanamide coordination bridges. Acta Cryst. 2015, 71, 717-720. (34) Lu, Y.; Liao, W. Q.; Hua, X. N., A new two-dimensional polymeric cadmium(II) complex containing dicyanamide bridging ligands. Acta Cryst. 2017, 73, 885-888. (35) Mączka, M.; Gągor, A.; Ptak, M.; Stefańskaa, D.; Sieradzki, A., Temperature-dependent studies of a new two-dimensional cadmium dicyanamide framework exhibiting an unusual temperature-induced irreversible phase transition into a three-dimensional perovskite-like framework. Phys. Chem. Chem. Phys. 2018, 20, 29951-29958. (36) Schlueter, J. A.; Manson, J. L.; Geiser, U., Structural and Magnetic Diversity in Tetraalkylammonium Salts of Anionic M[N(CN)2]3- (M =Mn and Ni) Three-Dimensional Coordination Polymers. Inorg. Chem. 2005, 44, 3194-3202. (37) Bermúdez-García, J. M.; Sánchez-Andújar, M.; Yáñez-Vilar, S.; Castro-García, S.; Artiaga, R.; López-Beceiro, J.; Botana, L.; Alegría, A.; Señarís-Rodríguez, M. A., Multiple phase and dielectric transitions on a novel multi-sensitive [TPrA][M(dca)3] (M: Fe2+, Co2+ and Ni2+) hybrid inorganic–organic perovskite family. J. Mater. Chem. C 2016, 4, 4889-4898. (38) Geng, F.-J.; Zhou, L.; Shi, P.-P.; Wang, X.-L.; Zheng, X.; Zhang, Y.; Fu, D.-W.; Ye, Q., Perovskite-type organic–inorganic hybrid NLO switches tuned by guest cations. J. Mater. Chem. C 2017, 5, 1529-1536. (39) Zhou, L.; Zheng, X.; Shi, P. P.; Zafar, Z.; Ye, H. Y.; Fu, D. W.; Ye, Q., Switchable Nonlinear Optical and Tunable Luminescent Properties Triggered by Multiple Phase Transitions in a Perovskite-Like Compound. Inorg. Chem. 2017, 56, 3238-3244. (40) Lever, T.; Haines, P.; Rouquerol, J.; Charsley, E. L.; Van Eckeren, P.; Burlett, D. J., ICTAC nomenclature of thermal analysis (IUPAC Recommendations 2014). Pure Appl. Chem. 2014, 86, 545-553.


Page 19 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(41) Yot, P.; Miele, P.; Demirci, U., In situ Synchrotron X-ray Thermodiffraction of Boranes. Crystals 2016, 6, 16. (42) Liu, H.; Zhang, W.; Halasyamani, P. S.; Stokes, H. T.; Campbell, B. J.; Evans, J. S. O.; Evans, I. R., Understanding the Behavior of the Above-Room-Temperature Molecular Ferroelectric 5,6-Dichloro-2-methylbenzimidazole Using Symmetry Adapted Distortion Mode Analysis. J. Am. Chem. Soc. 2018, 140, 13441-13448. (43) Spackman, M. A.; Jayatilaka, D., Hirshfeld surface analysis. CrystEngComm 2009, 11, 1932. (44) Samantaray, R.; Clark, R. J.; Choi, E. S.; Zhou, H.; Dalal, N. S., M3-x(NH4)xCrO8 (M = Na, K, Rb, Cs): A New Family of Cr5+-Based Magnetic Ferroelectrics. J. Am. Chem. Soc. 2011, 133, 3792-3795. (45) Samantaray, R.; Clark, R. J.; Choi, E. S.; Dalal, N. S., Elucidating the Mechanism of Multiferroicity in (NH4)3Cr(O2)4 and Its Tailoring by Alkali Metal Substitution. J. Am. Chem. Soc. 2012, 134, 15953-15962. (46) Jain, P.; Dalal, N. S.; Toby, B. H.; Kroto, H. W.; Cheetham, A. K., Order-Disorder Antiferroelectric Phase Transition in a Hybrid Inorganic-Organic Framework with the Perovskite Architecture. J. Am. Chem. Soc. 2008, 130, 10450-10451. (47) Jain, P.; Ramachandran, V.; Clark, R. J.; Zhou, H. D.; Toby, B. H.; Dalal, N. S.; Kroto, H. W.; Cheetham, A. K., Multiferroic Behavior Associated with an Order-Disorder Hydrogen Bonding Transition in Metal-Organic Frameworks (MOFs) with the Perovskite ABX3 Architecture. J. Am. Chem. Soc. 2009, 131, 13625-13627. (48) Xu, G.-C.; Ma, X.-M.; Zhang, L.; Wang, Z.-M.; Gao, S., Disorder-Order Ferroelectric Transition in the Metal Formate Framework of [NH4][Zn(HCOO)3]. J. Am. Chem. Soc. 2010, 132, 9588-9590.



Page 20 of 20

For Table of Contents Use Only Manuscript title: Temperature-induced structural phase transitions in two new post-perovskite coordination polymers Author list: Sha-Sha Wang, Rui-Kang Huang, Xiao-Xian Chen, Wei-Jian Xu, Wei-Xiong Zhang,* and Xiao-Ming Chen* TOC graphic:

Synopsis: Two new ABX3 molecular post-perovskites were constructed by chlorocholine as Asite cations, N(CN)2− as X-site bridges, and different metal ions as B-site cations, which endow them distinct order-disorder phase transitions. The smaller Mn2+ ion results in two-step Cmcm↔Pbcm↔Pbca transitions accompanying with dielectric relaxation, whereas the larger Cd2+ ion results in one-step Cmcm↔Pbca transition accompanying with a sharp dielectric switching.


Temperature-Induced Structural Phase Transitions in Two New

Recommend Documents