Modulation of Thermal Expansion by Guests and Polymorphism in a

Article pubs.acs.org/crystal

Modulation of Thermal Expansion by Guests and Polymorphism in a Hydrogen Bonded Host Viswanadha G. Saraswatula and Binoy K. Saha* Department of Chemistry, Pondicherry University, Puducherry 605 014, India S Supporting Information *

ABSTRACT: Thermal expansions of the three isostructural solvates of an “X”-shaped host molecule, 1,1,4,4-tetrakis(4hydroxyphenyl)cyclohexane (1), with phenol (1-ph), p-cresol (1-pc), and m-cresol (1-mc), two polymorphic solvates of 1 with o-cresol (1-oc-1D and 1-oc-2D), and a guest-free form of 1 (1-gf) have been studied. This work demonstrates that isostructural 1-ph and 1-pc show uniaxial negative thermal expansion (NTE), but along different directions and only the 1ph system undergoes single-crystal to single-crystal phase transformation. On the other hand, the isostructural 1-mc host lattice experiences a normal positive thermal expansion (PTE). The one-dimensional hydrogen bonded triclinic form of the o-cresol solvate (1-oc-1D) exhibits a biaxial NTE, whereas the two-dimensional hydrogen bonded monoclinic form (1-oc2D) exhibits a normal PTE. The 1-gf form experiences only a weak uniaxial NTE and smaller volumetric expansion compared to all the solvates. The uniaxial NTE that occurred in some of these materials is caused by sliding of the layers, made of hydrogen bonded tapes of the host molecules. The guest molecules experience stronger thermal vibration than the host molecules. Systems with a higher guest to the host ratio experience larger thermal expansions.

■

INTRODUCTION Generally, materials expand on heating along all the directions due to increasing molecular vibration, which is termed as positive thermal expansion (PTE). But in very few materials, this expansion is compensated for (a zero thermal expansion, ZTE)1−3 or overshadowed by (a negative thermal expansion, NTE)4−7 some other structural factors. Materials with ZTE or NTE properties have useful applications in fiber optic systems, electronic, high precision optical mirrors, cookware, packaging materials for refractive index gratings, biomedical field, etc.8,9 There are also some materials that show large anisotropy in their thermal expansion behavior. Very strong uniaxial PTE or NTE materials could be useful in the field of thermomechanical actuators.10−15 Although there are several reports on NTE in the case of metal oxides and zeolites, and also a few in the coordination compounds,16−33 there have been comparatively fewer thermal expansion studies on pure organic compounds.34−41,10−15 Generally the expansion in the bulk materials along a particular direction is estimated by analyzing the cell parameters of the crystal structures. In the case of thermal expansion (PTE or NTE), the structural changes occur smoothly over a range of temperature, and it is easy to compare the cell parameters to estimate the expansion in the materials along different directions. But in some of the systems, that undergo single-crystal to single-crystal phase transformation (SCSCPT) at a particular temperature, the structural changes are rather more drastic, and the cell alignment, symmetry, Z © 2015 American Chemical Society

values, etc. are usually changed after the phase transformation.42−50 In this work we have studied SCSCPT along with thermal expansion in the materials. There are only very few reports on the influence of guest and polymorphism on the thermal expansion behavior of host lattices.51−53,15,40,41 Isostructural systems are suitable to study the properties of molecules nullifying the structural effects, and polymorphic systems are suitable to study the structural effects nullifying the effects of the molecules. Here, we show guest-dependent thermal expansion behaviors in a set of isostructural host lattices and also show the differences in thermal expansion anisotropy between the polymorphs with different hydrogen bonding networks. Herein, we have studied thermal expansions of three isostructural solvates of 1,1,4,4-tetrakis(4-hydroxyphenyl)-cyclohexane, 1, with phenol (1-ph), p-cresol (1- pc), and m-cresol (1-mc), two polymorphic solvates of 1 with o-cresol (1-oc-1D and 1-oc-2D), and the guest-free form (1-gf) of 1 (Scheme 1).

■

RESULTS AND DISCUSSION Crystal Structures. The tailor-made “X”-shaped host molecule, 1, has two types of concave surfaces to accommodate the guest molecules. All three isostructural solvates are solved Received: August 6, 2014 Revised: December 22, 2014 Published: January 14, 2015 593

DOI: 10.1021/cg501178f Cryst. Growth Des. 2015, 15, 593−601

Article

Crystal Growth & Design Scheme 1. (a−d) Schematic Diagram of the Hydrogen Bonded Networks of Host Molecule, 1a

Figure 1. (a) Packing diagram of 1-ph (105 K data). Different colors have been used to distinguish different layers. (b) Packing diagram of the 1D chain structure in 1-oc-1D. Different colors have been used for different layers. (c) Packing diagram of 1-oc-2D. Different colors have been used for different layers. These layers are hydrogen bonded to form a 2D layer.

along the a axis via O−H···O hydrogen bonds through the ordered guest molecules (phenol). As a result of this stacking a channel is formed parallel to the a axis, running through two hydrogen bonded host molecules in a tape. This assembly forms a two-dimensional (2D) hydrogen bonded network (Scheme 1a) parallel to the crystallographic ab plane. Even though the overall network, connectivity, and the conformation of the host molecule do not change in these two phases, small reorientation of the ordered guest molecules, constructing the wall, is observed with decreasing temperature. The asymmetric unit of the 1-pc and 1-mc structures contain a half molecule of 1 and one molecule of p-cresol or m-cresol respectively, and the unit cell parameters of these two solvates are comparable to the HT cell of the 1-ph solvate. There are some highly diffused electron densities, which could not be modeled from the difference Fourier electron density map, located in the channel in these two systems. These electrons account for the presence of a small amount of highly disordered ethyl acetate and pcresol or m-cresol in nonstoichiometric proportions as suggested by the 1H NMR study (Figure S2, Supporting Information). Thermogravimetric (TG) experiments were also

a

(a) 2D hydrogen bonded network of the isostructural solvates; (b) 1D hydrogen bonded network in 1-oc-1D, (c) 2D hydrogen bonded network in 1-oc-2D, and (d) 2D hydrogen bonded network in 1-gf. Two consecutive layers are shown in different colors and hydrogen bonds are shown by the dotted line. In (a) −Ar represents the guest molecules constructing the channel wall.

in the P1̅ space group (see Figure S1 for ORTEP in the Supporting Information). The asymmetric unit of 1-ph consists of a half molecule of 1 along with one molecule of phenol (Z = 1, high temperature (HT) cell) at room temperature. Another half molecule of phenol, occupying the channel, is highly disordered and could not be modeled. Below 238 K the Z value increases to 2 (low temperature (LT) cell) due to the phase change via the SCSCPT process (see Tables S1 and S2 for crystallographic information in the Supporting Information). The host molecules form O−H···O hydrogen bonded tapes running along the b axis (Figure 1a). These tapes are connected 594


Article

Crystal Growth & Design performed to study the desolvation phenomena (Figure S3, Supporting Information). According to the 1H NMR/TG analysis the ratios of 1/phenol, 1/m-cresol/ethyl acetate, and 1/p-cresol/ethyl acetate are 1:3, 1:2.3:0.7, and 1:2.7:0.3, respectively. Unlike the 1-ph solvate, no phase transformation is observed in these two systems during the variable temperature experiments. The triclinic form of 1-oc (1-oc-1D) crystallizes in the P1̅ space group with a half molecule of 1 and one molecule of ocresol in the asymmetric unit. The host molecules form a onedimensional (1D) hydrogen bonded tapelike structure. The tapes are running along the [111] directions, and the guest molecule is linked to this tape via donating one O−H···O hydrogen bond (Figure 1b). The hydrogen bonding pattern in this structure is similar to the isostructural solvates discussed above, except that two consecutive tapes are not connected via hydrogen bonds through the guest molecules. Rather, one of the two symmetry independent O−H donors of the host molecule remains free and forms O−H···π interaction with the phenyl group of a host molecule of the neighboring tape. Tapes from two consecutive layers are stacked with a small offset in such a way that two different types of cavities are aligned one above the other to form a channel (Scheme 1b). The cavities, formed within the tape, are hydrogen bonded to the neighboring tapes. The monoclinic form of 1-oc (1-oc-2D) system crystallizes in the P21/n space group with a half molecule of 1 and one molecule of o-cresol in the asymmetric unit. The guest molecule is disordered over two sites, and in one of the sites it is further disordered over two orientations. There is a small difference in the hydrogen bonding pattern with respect to the 1D polymorph. In 1D polymorph, the host molecules are aligned parallel along the 1D tape, but in 2D polymorphic form, the two diagonal phenolic groups of the alternate host molecules are slightly twisted from parallel alignment along the 1D tape and form helical O−H···O hydrogen bonds with the neighboring 1D tape to produce a 2D hydrogen bonded network parallel to the (101) plane (Scheme 1c). The guest molecules donate O−H···O hydrogen bonds to the host molecules, similar to the 1D tape structure. These helical assemblies are interdigitated to each other via weak C−H···O interactions and van der Waals contacts. As a result of this assembly, a channel is formed along the helix axis and parallel to the crystallographic “b” axis (Figure 1c). These channels are filled by o-cresol guest molecules, hydrogen bonded to the neighboring interdigitated layer. Unlike the three isostructural solvates, where the OH groups of the guest molecules bridges between two host OH groups via donating and accepting H-bonds, the OH group of the o-cresol guest molecule, in each of the two polymorphs, forms only one H-bond via donating to the host OH groups, but cannot act as a H-bond acceptor due to steric hindrance of the Me group, substituted in the ortho position. This “ortho ef fect” makes the 1-oc solvates different from the other structures in this series. The guest-free form, 1-gf, crystallizes in P1̅ space group with only half molecule of 1 in the asymmetric unit. The molecules assemble in a planar 2D hydrogen bonded network via cyclic O−H···O hydrogen bonded tetramer (Figure 2a). These 2D networks are stacked parallel to the (111) crystallographic plane with a small offset, and the stacking interactions are of weak van der Waals type (Scheme 1d). Two of the four phenyl groups around the cavity are coplanar to the 2D sheet and hence occupy the cavity defying any space for accommodation

Figure 2. (a) One layer of 2D hydrogen bonded 1-gf form is shown. (b) Percent change in area of the 2D hydrogen bonded layer, interplanar distance, centroid-to-centroid distance of the molecules along the tape and across the tape within the 2D layer are plotted against temperature.

of the guest molecule. The hydrogen bond network in this structure is similar to the host network of 1-oc-1D, except that the neighboring tapes in a plane are connected via hydrogen bonds. Thermal Expansion along the Principal Axes. We have studied thermal expansion properties in these systems by employing single crystal X-ray data collection at different temperatures. Because of phase transformation in 1-ph, cell parameters have been collected between 108 and 298 K temperature range at a 10 K interval for all the three isostructural solvates, and these cell parameters (Table S2) have been used for the calculation of thermal expansion coefficients for these three structures. The thermal expansion coefficients along the principal axes and the volumetric thermal expansion coefficients for the systems are shown in Figure 3 (Table S3, Figures S4 and S5). In the course of variable temperature experiments, we have noticed normal PTE in the 1-mc system but a prominent uniaxial NTE and a very strong PTE along the principal axes in the 1-ph and 1-pc systems among the three isostructural solvates. Very recently, Barbour et al.15 reported an interesting case of tuning of thermal expansion of a Zn(II) based metal organic framework (MOF) by changing guest molecules. They used methanol, ethanol, n-propanol, and isopropanol as the guest and showed that PTE along the major principal axis decreases with increasing length of the guest molecules. In 595


Article

Crystal Growth & Design

Figure 3. (a) The bar diagrams show the thermal expansion coefficients along the three principal axes and in volumes for the six systems. Directions of the principal axes are shown in (b) 1-gf, (c) 1-oc-2D, (d) 1-oc-1D, (e) 1-mc, (f) 1-pc, and (g) 1-ph. In 1-gf the view is perpendicular to the 2D plane, whereas in the other five systems the views are along the channel axes. In (b), (c), and (d) the bottom layers are shown in blue colors. X3 is directed along the b axis in (c).

contrast to their result, where the isostructural host networks showed a constant thermal expansion behavior, our isostructural systems showed a different trend. The PTE value along

the major axis for the MeOH solvate in their system was as high as 166(4) MK−1. As a result of this high value, the thermal expansion was also observed in the macroscopic level. In our 596


Article


via crystallization through slow evaporation of solvent. The MOF apo-hosts, reported earlier, were thermodynamically unstable species, but this guest-free form is a stable entity. Among the reported organic systems, the influence of guest molecules on the thermal expansion of host networks has been reported by White et al.38 in a Dianin’s-ethanol solvate and very recently by our group39 in a series of halogenated compounds. Comparison of the average hydrogen bond distances in these six systems suggests that O−H···O hydrogen bonds are relatively stronger in the three isostructural systems which are followed by guest-free form and are weakest in the two polymorphic solvates (Figure 4). In contrast, the order of

work, we have shown much higher NTE and PTE values along the principal axes in the three isostructural solvates. The thermal expansion coefficient values along the minor and major principal axes of the isostructural 1-ph, 1-pc, and 1-mc solvates are −100(8), −50(2), 29(3) MK−1 and 276(15), 176(4), 68(2) MK−1 respectively, and the volumetric thermal expansion coefficients for these systems are 228(8), 179(5), and 160(7) MK−1 respectively. Therefore, the 1-ph system exhibits more prominent uniaxial NTE and PTE as well as higher average volumetric thermal expansion coefficient values compared to the other two isostructural solvates. It should be noted that the volumetric thermal expansion coefficient, calculated for the LT phase (108−228 K) of 1-ph, is 164(13) MK−1, whereas for the HT phase (238−198 K) it is 197(11) MK−1. Only very recently, during the preparation of this manuscript, Barbour et al. have reported a very high PTE (282(16) MK−1) and NTE (−129(15) MK−1) in the crystal structure of a nitromethane solvate of 18-crown-6.40 Therefore, the present one could possibly be the second report where such large PTE and NTE along different principal axes have been observed among the organic solvates, and here we have studied the effect of the guest molecules in more detail. Recently, we reported thermal expansion properties of a dimorphic organic complex where both the structures were made of two 1D hydrogen bonded parallel chains.37 Because of similarities in the hydrogen bonded topologies and structural packing, their thermal expansion behaviors were also found to be similar. But in the present report, the two polymorphic solvates have different hydrogen bonded networks. Therefore, it could be interesting to study their comparative thermal expansion properties. The linear thermal expansion coefficient values along the three principal axes of the 1D and 2D 1-oc polymorphic solvates are found to be −23(4), −3(8), 148(5) MK−1 and 18(3), 40(1), 69(1) MK−1 respectively, whereas their volumetric thermal expansion coefficients are 124(8) and 128(3) MK−1 respectively. Therefore, the 2D form exhibits normal PTE along all the three directions (115−298 K). In contrast, the 1D form shows uniaxial NTE, ZTE, and PTE (120−298 K) along the X1, X2, and X3 principal axes, respectively. Therefore, all the three types of expansions coexist in the same system. Coexistence of all the three types of expansions in the same system was recently reported by Barbour and co-workers in the before mentioned 18-crown6.CH3NO2 system.40 Interestingly, though the expansion anisotropies in the present two polymorphic systems are widely different from each other, the overall volumetric expansions are very similar. This result signifies the influence of network and packing on the anisotropic thermal expansion property of a host lattice. The 2D hydrogen bonded 1-gf form experiences only a weak uniaxial NTE (−8(2) MK−1) and a moderate biaxial PTE (27(2), 71(2) MK−1) in the temperature range 118−298 K. The volumetric thermal expansion coefficient in the 1-gf form is least (94(7) MK−1) in this lot. This clearly indicates that the guest molecules can influence and increase the thermal expansion of a host network.15 Similar observations were reported previously by Kepert et al. and Omary et al. in cadmium cyanide diamondoid network and fluorous MOF respectively.54,19 But one important difference with these reported systems is that these MOF host−guest systems have been compared with the apo-host, i.e., after removal of the guests from the host lattice without changing the network, whereas in the present report the guest-free form was obtained

Figure 4. Average hydrogen bond distances in the six systems at different temperatures.

volumetric thermal expansion coefficients is found to be as guest-free form < two polymorphic solvates < three isostructural solvates. Therefore, hydrogen bond interaction alone could not explain the relative volumetric thermal expansion properties. In this series of structures, the guest to host ratio increases as 1-gf (0:1) < polymorphic 1-oc solvates (2:1) < isostructural 1-ph, 1-mc, and 1-pc solvates (3:1). Interestingly, this is also the order of volumetric thermal expansion in these systems. Hence, higher guest content causes larger thermal expansion in the lattice. Comparison of the Ueq Values. Atomic vibration of the molecules in a material increases with increasing temperature,55,56 and therefore, atomic vibration is one of the important factors that might control some of the thermal expansion properties in the materials.36,41 Comparison of the average equivalent isotropic atomic displacement parameters (ADP) values (Ueq) of the ordered molecules in this series of structures reveals that not only the guest molecules experience larger thermal vibration than the host molecule, but the thermal vibration of the guest atoms also increases faster (as suggested by the steeper slope) than the host atoms with increasing temperature (Figure 5). It should be noted that the guests, reported here, have lower MP than the host, and in fact the guest molecules are liquids at room temperature. We also have compared the average Ueq values of the host molecules, 1, in the solvates with 1 in the 1-gf form. Except 1-oc-2D solvate, where the atomic vibrations of 1 is comparable to the 1-gf form, 1 in all the other four solvates exhibit larger atomic vibrations than 1 in the 1-gf form in (Figure 5). Therefore, in this series of structures not only the solvent guest molecules possess larger atomic vibration but also the host molecules experience larger atomic vibration compared to that in the guest-free form. This might be due to the close 597


Article


Sliding, along the tape axis and across it, can be monitored by the changes in the angles θ1 and θ2 respectively (Figure 6,

Figure 6. (a) Schematic diagram of two layers (red and black) of hydrogen bonded tapes of 1, and the angles θ1 and θ2 are shown. (b) Change in angles, θ1 and θ2, are plotted against temperature.

Table S4). In the case of 1-mc solvate, the changes in these two angles are negligible and hence the structure shows normal PTE. But these changes are considerably high in the case of 1ph, 1-pc, and 1-oc-1D solvates. The average values of θ1 decrease and θ2 increase with increasing temperature for the 1ph structures, whereas it is just the reverse in the case of 1-pc structure. Therefore, sliding of the tapes in these two structures occurs in opposite directions along the tape, even though they are apparently isostructural. On the other hand, both the angles (θ1 and θ2) decrease with increasing temperature in 1-oc-1D. Although in all four structures the intertape distances increase with increasing temperature, this effect is outweighed by sliding of the tapes, and two lattice points come closer along a particular direction at higher temperature and hence an NTE is observed along that direction.35 From Figure 6, it is clear that the system, which shows larger changes in the θ1 and θ2 angles, also exhibits prominent uniaxial NTE or PTE in this series. The 1-gf, three isostructural solvates, and the 1-oc-2D solvate form 2D hydrogen bonded layers. Comparison of the area of these layers suggests that the change in area with temperature in the 1-gf form is the least and it is highest in the case of 1-ph solvate (Figure 7). The guest molecules occupy the cavities generated in the 2D hydrogen bonded host lattices. As the thermal vibration of the guests are significantly higher than the host molecules, the area of the host network changes rapidly with temperature. Phenol, possessing higher thermal atomic vibration compared to other guest molecules, influences the host network most in the lot. In the case of 1-pc system, the average hydrogen bond distance (O···O) increases from 2.660(2) Å at 115 K to 2.680(4) Å at 298 K. In contrast, it does not increase

Figure 5. Mean ADP values of the hosts and guests are plotted against temperature for the (a) 1-ph, 1-pc, 1-mc, and 1-gf; (b) 1-oc-1D, 1-oc2D, and 1-gf systems. Densities of the two polymorphic forms at different temperatures are shown. 1-oc-2D form poses higher density at all the temperatures compared to the 1-oc-1D form.

packing of the guest molecules in the cavities, and hence the vibrations of the host molecules are influenced by the vibration of the guest molecules. Generally, atoms vibrate more strongly in the direction of lower packing fraction.57 The 2D polymorph poses higher density than that of 1D polymorph (Figure 5b), and therefore the packing fraction of 2D form (68.9% at 298 K) is also higher than that of the 1D form (68.1% at 298 K). This results into smaller atomic vibration in the host as well as in the guest molecules in the denser 2D polymorph (Figure 5b). In spite of the absence of any guest molecule in the lattice, due to considerably low packing fraction (65.8% at 298 K), the average Ueq values of the 1-gf form is comparable to the denser 2D polymorph. The lower packing fraction of the guest free structure compared to its solvates indicates why the compound 1 prefers to form inclusion lattices. Structural Changes. In the crystal structures, the “X”shaped host molecules form primarily hydrogen bonded molecular tapes. Along the channel axis, they are hydrogen bonded through guest molecules in the cases of isostructural 1ph, 1-pc, and 1-mc solvates but are stacked via van der Waals interactions in the 1-oc-1D solvate. A close inspection of the structures at different temperatures reveals that the tapes start sliding as the temperature changes. 598



Article

■

EXPERIMENTAL SECTION

■

ASSOCIATED CONTENT

Synthesis. 1 was synthesized by slightly modifying the reported procedure to prepare 4,4-bis(4-hydroxyphenyl)cyclohexanone.62 To the mixture of 500 mg (4.46 mmol) of cyclohexane-1,4-dione, 6710 mg (71.40 mmol) phenol, 20 mL of water, and 20 mL of 1,4-dioxane, 20 mL of sulfuric acid was added dropwise at 0 °C. The reaction mixture was stirred at room temperature for 72 h and then neutralized with sodium bicarbonate solution. Compound 1 was isolated by column chromatography using ethyl acetate−hexane (1:3) solvent mixture with a yield of 18%. M. P. 337(2) °C. 1 H-NMR. (400 MHz, DMSO-d6): δ 9.22 (s, 4H), 7.03 (s, broad, 8H), 6.59 (s, broad, 8H), 2.50 (s, broad, 4H), 1.74 (s, broad, 4H) ppm. Crystallizations. 1-ph single crystals were obtained by slow evaporation method of the solvent from a phenolic solution of compound 1. 1-pc, 1-mc, and concomitant polymorphs of 1-oc were obtained by slow evaporation of the solvents from a 5:1 solvent mixture of ethyl acetate with p-cresol, m-cresol, and o-cresol, respectively. The 1-gf form was obtained by slow evaporation of the solvent from a 1:1 mixture of the compound, 1, and alanine in methanol. Structure Determinations. X-ray crystal data were collected on Xcalibur Eos Oxford Diffraction Ltd. with Mo−Kα radiation (λ = 0.71073 Å). Temperature was controlled with an Oxford Cryojet HT instrument. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm were applied.63 Structure solution and refinement were performed with SHELXS64 and SHELXL65 respectively using Olex2-1.166 software package. All the hydrogen atoms were placed in the calculated positions using riding model. SQUEEZE67 routine of PLATON68 was used to treat the residual electron density originated from disordered guest molecules in the 1-ph, 1-pc, and 1-mc structures. The guest molecule in 1-oc-1D is disordered and the major part has been modeled. The guest molecule in the 1-oc-2D form is also disordered over two sites, and in one of the sites it is further disordered over two orientations. SADI command has been used to refine the disordered o-cresol ring (C16B−C21B) for all the six structures, and EADP command has been used to refine C16A and C16B atoms for the 115 K-220 K data sets. Thermal Expansion Calculations. The thermal expansion coefficients have been calculated using the PASCal69 program. Unlike 1-pc and 1-mc, the 1-ph system undergoes SCSCPT during the course of variable temperature treatment in the temperature range 298 to 105 K. Though there is no change in the overall network structure, due to the change in Z values in these two phases, direct comparison of the unit cell parameters has not been possible in this case. In the process of phase transfer the a axis in the LT phase has been doubled to that of HT phase. Therefore, to calculate thermal expansion coefficients the a axis and hence the volume of the HT phases have been doubled and compared with the LT phases (see Figure S7 in the Supporting Information). Thermal Gravimetry. TG experiments were performed on a TA Instrument. Crystals taken from the mother liquor were made dry on tissue paper and placed in open alumina pans for TG experiment. Around 5−11 mg of the sample was used for each TG experiment. The samples were heated at a rate of 10 °C/min. NMR. 1H NMR spectra were recorded on a 400 MHz Bruker Avance-II spectrometer.

Figure 7. Percent changes in area are plotted with respect to the temperature in the 2D hydrogen bonded networks.

in the case of 1-ph system (2.680(4) Å at 105 K to 2.679(4) Å at 298 K). In fact, some of the hydrogen bonds are considerably shorter at higher temperature in this network (Figure S6 and Table S5). Each molecule in the 1-gf form is hydrogen bonded to four neighboring molecules (Figure 2a). The centroid-to-centroid distance of the molecules along one of the two hydrogen bonded directions is actually decreasing with increasing temperature in this material (Figure 2b). Figure 2b also shows that expansion in 2D hydrogen bonded area is smaller than the expansion along the interplanar distance which is guided by weak van der Waals interactions.

■

CONCLUSIONS In summary, we have studied thermal expansion properties of three isostructural host58−61 networks, two polymorphic solvates, and one guest-free form of an organic compound containing hydrogen bond functionality. Therefore, the thermal expansion properties of these three isostructural solvates differ not only quantitatively but also by means of the nature of expansion depending upon the guest molecules. Lattices with higher guest content are shown to possess larger volumetric thermal expansion. The ADP values of the guest molecules have been shown to be higher than the host molecules in these systems. We have shown the influence of different networks on the anisotropy of thermal expansion in polymorphic solvates. But it has been noticed that the effect of guest molecules on thermal expansion of the material is more prominent than the effect of polymorphism in this series. It has been shown that the thermal expansion of any host− guest systems could be tuned by varying guest molecules,15 and host−guest systems could be useful where large thermal expansion materials are required in designing a device, e.g., thermomechanical actuators. In this work we have noticed that the guest-free form, with the lowest packing fraction, shows minimum thermal expansion compared to the solvates with higher packing fractions. Therefore, an apohost, with a very low packing coefficient, might be a good choice for showing volumetric NTE or small PTE property in the material.54 We anticipate that this work would encourage studying the thermal expansion properties of the solvates of different types of hosts and also the wide range of polymorphic systems.

S Supporting Information *

ORTEP diagrams, thermogravimetric plot, 3D plot of thermal expansion coefficients, 1H NMR data for the 1-gf, 1-mc, and 1pc systems, alignment of the principal axes with respect to the crystal packing, change in hydrogen bond length in 1-ph and 1pc, tables for crystallographic parameters, coefficient of thermal expansion, thermal expansion coefficients values, average values of θ1 and θ2, hydrogen bond interaction geometries. 599


Article


(24) Sahoo, P. P.; Sumithra, S.; Madras, G.; Guru Row, T. N. Inorg. Chem. 2011, 50, 8774−8781. (25) Marinkovic, B. A.; Ari, M.; de Avillez, R. R.; Rizzo, F.; Ferreira, F. F.; Miller, K. J.; Johnson, M. B.; White, M. A. Chem. Mater. 2009, 21, 2886−2894. (26) Villaescusa, L. A.; Lightfoot, P.; Teat, S. J.; Morris, R. E. J. Am. Chem. Soc. 2001, 123, 5453−5459. (27) Wang, J.; Deng, J.; Yu, R.; Chen, J.; Xing, X. Dalton Trans. 2011, 40, 3394−3397. (28) Lind, C.; Wilkinson, A. P.; Hu, Z.; Short, S.; Jorgensen, J. D. Chem. Mater. 1998, 10, 2335−2337. (29) Evans, J. S. O.; Mary, T. A.; Vogt, T.; Subramanian, M. A.; Sleight, A. W. Chem. Mater. 1996, 8, 2809−2823. (30) Evans, J. S. O.; Mary, T. A.; Sleight, A. W. J. Solid State Chem. 1997, 133, 580−583. (31) Martínez-Iñesta, M. M.; Lobo, R. F. J. Phys. Chem. B 2005, 109, 9389−9396. (32) Carey, T.; Corma, A.; Rey, F.; Tang, C. C.; Hriljac, J. A.; Anderson, P. A. Chem. Commun. 2012, 48, 5829−5831. (33) Woodcock, D. A.; Lightfoot, P. Chem. Mater. 1999, 11, 2508− 2514. (34) Birkedal, H.; Schwarzenbach, D.; Pattison, P. Angew. Chem., Int. Ed. 2002, 41, 754−756. (35) Bhattacharya, S.; Saha, B. K. Cryst. Growth Des. 2012, 12, 4716− 4719. (36) Bhattacharya, S.; Saraswatula, V. G.; Saha, B. K. Cryst. Growth Des. 2013, 13, 3651−3656. (37) Bhattacharya, S.; Saha, B. K. Cryst. Growth Des. 2013, 13, 3299− 3302. (38) Zakrzewski, M.; White, M. A.; Abriel, W. J. Phys. Chem. 1990, 94, 2203−2206. (39) Saraswatula, V. G.; Saha, B. K. New J. Chem. 2014, 38, 897−901. (40) Engel, E. R.; Smith, V. J.; Bezuidenhout, C. X.; Barbour, L. J. Chem. Commun. 2014, 50, 4238−4241. (41) Bhattacharya, S.; Saha, B. K. CrystEngComm 2014, 16, 2340− 2343. (42) Das, D.; Engel, E.; Barbour, L. J. Chem. Commun. 2010, 46, 1676−1678. (43) Zhang, Y.-J.; Liu, T.; Kanegawa, S.; Sato, O. J. Am. Chem. Soc. 2009, 131, 7942−7943. (44) Bhattacharya, S.; Stojaković, J.; Saha, B. K.; MacGillivray, L. R. Org. Lett. 2013, 15, 744−747. (45) Takahashi, S.; Miura, H.; Kasai, H.; Okada, S.; Oikawa, H.; Nakanishi, H. J. Am. Chem. Soc. 2002, 124, 10944−10945. (46) Sarma, D.; Natarajan, S. Cryst. Growth Des. 2011, 11, 5415− 5423. (47) Mir, M. H.; Vittal, J. J. Cryst. Growth Des. 2008, 8, 1478−1480. (48) Skakle, J. M. S.; Low, J. N.; Wardell, J. L.; Glidewell, C. Acta Crystallogr., Sect. B 2005, 61, 321−328. (49) Zhang, J.-P.; Lin, Y.-Y.; Zhang, W.-X.; Chen, X.-M. J. Am. Chem. Soc. 2005, 127, 14162−14163. (50) Hu, C.; Englert, U. Angew. Chem., Int. Ed. 2005, 44, 2281−2283. (51) Bolotina, N. B.; Hardie, M. J.; Speer, R. L., Jr; Pinkerton, A. A. J. Appl. Crystallogr. 2004, 37, 808−814. (52) Parat, B.; Pardo, L. C.; Barrio, M.; Tamarit, J. L.; Negrier, P.; Salud, J.; López, D. O.; Mondieig, D. Chem. Mater. 2005, 17, 3359− 3365. (53) Wójcik, G.; Mossakowska, I. Acta Crystallogr., Sect. B 2006, 62, 143−152. (54) Phillips, A. E.; Goodwin, A. L.; Halder, G. J.; Southon, P. D.; Kepert, C. J. Angew. Chem., Int. Ed. 2008, 47, 1396−1399. (55) Aree, T.; Bürgi, H.-B. J. Phys. Chem. A 2012, 116, 8092−8099. (56) Sales, B. C.; Chakoumakos, B. C.; Mandrus, D.; Sharp, J. W. J. Solid State Chem. 1999, 146, 528−532. (57) Newnham, R. E. In Properties of Materials; Oxford University Press: New York, 2005. (58) Banerjee, R.; Bhatt, P. M.; Desiraju, G. R. Cryst. Growth Des. 2006, 6, 1469−1478. (59) Das, D.; Barbour, L. J. Cryst. Growth Des. 2009, 9, 1599−1604.

Crystallographic data in cif format for the structures with CCDC 903694−903705, 955176−955191, 955193−955197, and 986048. This material is available free of charge via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Funding

B.K.S. thanks Council of Scientific and Industrial Research, India (No. 02(0026)/11/EMR-II) for financial support, V.G.S. thanks UGC for a fellowship. Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS B.K.S. thanks DST-FIST for single crystal X-ray diffractometer and CIF, Pondicherry University for NMR and TG facility. REFERENCES

(1) Salvador, J. R.; Guo, F.; Hogan, T.; Kanatzidis, M. G. Nature 2003, 425, 702−705. (2) Hu, P.; Chen, J.; Sun, X.; Deng, J.; Chen, X.; Yu, R.; Qiao, L.; Xing, X. J. Mater. Chem. 2009, 19, 1648−1652. (3) Phillips, A. E.; Halder, G. J.; Chapman, K. W.; Goodwin, A. L.; Kepert, C. J. J. Am. Chem. Soc. 2010, 132, 10−11. (4) Sleight, A. W. Annu. Rev. Mater. Sci. 1998, 28, 29−43. (5) Evans, J. S. O. J. Chem. Soc. Dalton. Trans. 1999, 3317−3326. (6) Barrera, G. D.; Bruno, J. A. O.; Barron, T. H. K.; Allan, N. L. J. Phys.: Condens. Matter 2005, 17, R217−R225. (7) Miller, W.; Smith, C. W.; Mackenzie, D. S.; Evans, K. E. J. Mater. Sci. 2009, 44, 5441−5451. (8) Roy, R.; Agrawal, D. K.; McKinstry, H. A. Annu. Rev. Mater. Sci. 1989, 19, 59−81. (9) Tran, K. D.; Groshens, T. J.; Nelson, J. G. Mater. Sci. Eng. 2001, A303, 234−240. (10) Li, L.; Xu, X.; Chew, H.; Huang, X.; Dou, X.; Pan, S.; Li, G.; Zhang, L. J. Phys. Chem. C 2008, 112, 5328−5332. (11) Noailles, L. D.; Peng, H.-H.; Starkovich, J.; Dunn, B. Chem. Mater. 2004, 16, 1252−1259. (12) Dubbeldam, D.; Walton, K. S.; Ellis, D. E.; Snurr, R. Q. Angew. Chem., Int. Ed. 2007, 46, 4496−4499. (13) DeVries, L. D.; Barron, P. M.; Hurley, E. P.; Hu, C.; Choe, W. J. Am. Chem. Soc. 2011, 133, 14848−14851. (14) Das, D.; Jacobs, T.; Barbour, L. J. Nat. Mater. 2010, 9, 36−39. (15) Grobler, I.; Smith, V. J.; Bhatt, P. M.; Herbert, S. A.; Barbour, L. J. J. Am. Chem. Soc. 2013, 135, 6411−6414. (16) Lightfoot, P.; Woodcock, D. A.; Maple, M. J.; Villaescusa, L. A.; Wright, P. A. J. Mater. Chem. 2001, 11, 212−216. (17) Goodwin, A. L.; Calleja, M.; Conterio, M. J.; Dove, M. T.; Evans, J. S. O.; Keen, D. A.; Peters, L.; Tucker, M. G. Science 2008, 319, 794−797. (18) Khosrovani, N.; Sleight, A. W. J. Solid State Chem. 1997, 132, 355−360. (19) Yang, C.; Wang, X.; Omary, M. A. Angew. Chem., Int. Ed. 2009, 48, 2500−2505. (20) Wu, Y.; Kobayashi, A.; Halder, G. J.; Peterson, V. K.; Chapman, K. W.; Lock, N.; Southon, P. D.; Kepert, C. J. Angew. Chem., Int. Ed. 2008, 47, 8929−8932. (21) Govindaraj, R.; Sundar, C. S.; Arora, A. K. Phys. Rev. B 2007, 76, 1−4. (22) Shepherd, H. J.; Palamarciuc, T.; Rosa, P.; Guionneau, P.; Molnár, G.; Létard, J.-F.; Bousseksou, A. Angew. Chem., Int. Ed. 2012, 51, 3910−3914. (23) Mary, T. A.; Evans, J. S. O.; Vogt, T.; Sleight, A. W. Science 1996, 272, 90−92. 600


Article

Crystal Growth & Design (60) Saha, B. K.; Nangia, A. Cryst. Growth Des. 2007, 7, 393−401. (61) Bhattacharya, S.; Saha, B. K. Cryst. Growth Des. 2013, 13, 606− 613. (62) Aitipamula, S.; Desiraju, G. R.; Jaskólski, M.; Nangia, A.; Thaimattam, R. CrystEngComm 2003, 5, 447−450. (63) CrysAlisPro, Version 1.171.33.66; Oxford Diffraction Ltd.: Abingdon, U.K., 2010. (64) Sheldrick, G. M. SHELXS-97, Programs for the Solution of Crystal Structures; University of Gottingen: Germany, 1997. (65) Sheldrick, G. M. SHELXS. Acta Crystallogr., Sect. A 2008, 64, 112−122. (66) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. J. Appl. Crystallogr. 2009, 42, 339−341. (67) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7−13. (68) Spek, A. L. Acta Crystallogr., Sect. D 2009, 65, 148−155. (69) Cliffe, M. J.; Goodwin, A. L. J. Appl. Crystallogr. 2012, 45, 1321− 1329.

601


Modulation of Thermal Expansion by Guests and Polymorphism in a

Recommend Documents