High-Pressure-Induced Planarity of the Molecular Arrangement in

Article pubs.acs.org/JPCC

High-Pressure-Induced Planarity of the Molecular Arrangement in Maleic Anhydride Yuxiang Dai,† Kai Wang,*,† Xiaodong Li,‡ and Bo Zou*,† †

State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China Beijing Synchrotron Radiation Laboratory, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China

‡

S Supporting Information *

ABSTRACT: Maleic anhydride, an industrially important chemical, was investigated by conducting in situ high-pressure Raman scattering and synchrotron angle-dispersive X-ray diffraction (ADXRD) experiments at a pressure of up to 1.0 GPa. Drastic discontinuities of Raman modes at 0.5 GPa indicated that a phase transition occurred when pressure was elevated. This transformation is further discussed by analysis of the ADXRD results. The Raman spectra and X-ray diffraction patterns of the recovered samples indicated that this pressureinduced transformation is reversible. The calculated results by the first-principle method indicated that the pressure-induced planarity of molecular arrangement is the mechanism of this transition. This study shows that the pressure-induced phase transition of maleic anhydride at 0.5 GPa is derived from supramolecular rearrangements.

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INTRODUCTION Millions of pounds of maleic anhydride (C4H2O3) and its derivatives are produced per year with a high capacity.1 Maleic anhydride is an important industrial chemical used mainly for preparing pharmaceutical products, agricultural chemical products, unsaturated polyesters, and chemical additives.2 Maleic anhydride participates in many reactions associated with pressure.2−9 The effects of pressure on molecular materials in diverse fields (e.g., materials science, chemical synthesis, magnetism, and biophysics) are interesting.10−16 However, no report on the molecular behavior of maleic anhydride under high pressure has been published. Pressure can facilitate molecule close packing and alter intermolecular interactions, thereby resulting in changes in molecular arrangements.17−20 Therefore, the crystal structure and physicochemical properties of maleic anhydride are potentially affected by pressure. Considerable literature has reported that maleic anhydride molecules are not absolutely planar.21 The crystal structure of maleic anhydride is monoclinic under ambient conditions (phase I), whose space group is P212121. According to previous reports,21 the nearest intermolecular neighbors are hydrogen and oxygen atoms. Figure 1b shows that the formation of zigzag chains of molecules along the b-direction is an interesting structural feature. Several studies investigated and discussed the intermolecular noncovalent interactions in maleic anhydride crystals.21,22 Most of these studies showed that adjacent maleic anhydride molecules within the chain are held together by H··· O interactions. However, only van der Waals forces exist among maleic anhydride molecules because the geometric properties of intermolecular interactions are not associated with C−H···O © XXXX American Chemical Society

Figure 1. (a) Structural formula of maleic anhydride. (b) Crystal structure of maleic anhydride under ambient conditions. The gray region represents the molecular chain of maleic anhydride.

hydrogen bonds. As a consistent subject of extensive research, the van der Waals interaction, as a kind of noncovalent interaction, can affect the structural stability and property of chemical systems.23,24 Given that intermolecular noncovalent interactions can easily be changed or enhanced by compression, application of pressure is efficient to investigate these weak intermolecular interactions. Such investigations identified the fundamental application value of pressure-responsive materials.25−31 Thus, investigating noncovalent interactions in maleic anhydride crystals under high pressure is also interesting. We investigated the molecular arrangement and crystal structure of maleic anhydride by applying in situ high-pressure Raman spectroscopy and angle-dispersive X-ray diffraction (ADXRD) techniques in this study. First-principle calculations Received: June 23, 2016 Revised: July 16, 2016

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DOI: 10.1021/acs.jpcc.6b06351 J. Phys. Chem. C XXXX, XXX, XXX−XXX

Article

The Journal of Physical Chemistry C

Figure 2. Raman spectra of maleic anhydride at selected pressures (0.2−1.0 GPa). The arrows denote the new Raman modes: (a) 50−250 cm−1, (b) 250−1330 cm−1, (c) 1400−2000 cm−1, and (d) 2800−3400 cm−1.

monochromatic beam (wavelength maintained as 0.6199 Å) was 20 × 30 μm2. CeO2 standard was used to calibrate the distance of the sample detector and the geometric parameters. The Fit2D software was utilized to integrate the ADXRD patterns, which were collected by the Mar345 detector.33 Materials Studio 5.0 was used to analyze the ADXRD patterns to obtain detailed information on the crystal structure of maleic anhydride under high pressure. The geometric optimization of the high-pressure crystal structure was calculated using the pseudopotential plane wave method in the CASTEP code.34,35 The generalized gradient approximation36 of Perdew−Burke− Ernzerh was used37 with a plane wave cutoff energy of 660 eV.

were also used to elucidate the changes in molecular arrangement under high pressure. Through this study, we aimed to provide useful information on the high-pressure behavior of maleic anhydride.

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EXPERIMENTAL SECTION Maleic anhydride (99% from Aldrich) was used without further purification. A symmetric diamond anvil cell was utilized to conduct high-pressure Raman and ADXRD experiments. A piece of T301 steel with a preindented 40 μm gasket, in which a 130 μm compartment was predrilled, was placed between the parallel diamonds. Maleic anhydride powder crystals were loaded in the compartment with a ruby ball from which the pressure can be deduced through the ruby fluorescence method.32 Nitrogen and silicon oil were used as the transmitting medium of pressure for Raman and ADXRD experiments, respectively. The temperature condition of the high-pressure experiments was maintained at approximately 298 K. An Acton SpectraPro 2500i spectrometer with chargecoupled device camera (Pylon, 100B) cooled by liquid nitrogen was used to obtain high-pressure Raman data. The 10 mW 532 nm laser line was applied for each Raman spectrum with 30 s as the integration time. The 4W2 beamline at the High-Pressure Station of Beijing Synchrotron Radiation Facility was applied for in situ high-pressure ADXRD experiments. The size of the

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RESULTS AND DISCUSSION The point group symmetry of the maleic anhydride molecule is D2 (222). The mechanical representation of this symmetry is M = 27A + 27B1 + 27B2 + 27B3

showing 3 acoustic modes Γacoustic = B1 + B2 + B3

and 105 optic modes Γoptic = 27A + 26B1 + 26B2 + 26B3

Group-theoretical analysis of the vibrations shows that, among the 105 optical modes, the Raman-active modes belong B


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Figure 3. Pressure dependence of Raman shifts of maleic anhydride (0.2−1.0 GPa). The dashed lines denote the boundary of phases I and II: (a) 60−150 cm−1, (b) 270−425 cm−1, (c) 550−660 cm−1, (d) 766−844 cm−1, (e) 865−975 cm−1, (f) 1050−1325 cm−1, (g) 1550−1875 cm−1, and (h) 2850−3200 cm−1.

to the 27A + 26B1 + 26B2 + 26B3 symmetry and the infraredactive modes belong to the 26B1 + 26B2 + 26B3 symmetry. Some of the Raman modes could not be observed in our experiments because of the weak intensities and limited splitting between correlation components. Assignments for the Raman modes of maleic anhydride are based on literature.38,39 In this study, the Raman spectra of maleic anhydride were measured at a pressure of up to 1.0 GPa. The maleic anhydride Raman spectra at various pressures are presented in Figures 2a−d. The simultaneous changes in many of the Raman modes reveal that maleic anhydride underwent a structural transition at 0.5 GPa. The frequency shifts in the Raman modes shown in Figure 3 indicate the existence of the high-pressure phases. At approximately 0.5 GPa, the shifts of several vibrational modes were discontinuous, whereas the slopes of other modes

suddenly changed. These phenomena were also accompanied by the appearance of several new modes and the disappearance of initial modes. The observed Raman spectra provide some information on the changes in molecular arrangement in the high-pressure phase. Figure 2 depicts the Raman spectra of maleic anhydride from 0.2 to 1.0 GPa. The Raman spectra of the external modes in Figure 2a are translational and librational vibrations at several pressures. Figure 3a shows the peak positions which correspond to pressure in the range of 60−150 cm−1 from 0.2 to 1.0 GPa. The Raman spectrum at 0.2 GPa consists of five external modes (63, 74, 92, 108, and 118 cm−1). At 0.5 GPa, all of the external modes shifted abruptly, indicating the start of a pressureinduced phase transition. Another external mode emerged at 0.6 GPa. With continuous compression, the blueshifts of external modes indicate that the intermolecular interactions C


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Figure 4. Raman spectra of maleic anhydride at 1 atm and the released samples.

were enhanced.40,41 All of these changes in external modes indicated that a pressure-induced phase transition (phase I to II) clearly occurred at approximately 0.5 GPa. The internal modes can be used to investigate molecular variations, which reflect the chemical environment around specific groups. As shown in Figures 2b−d, significant discontinuities of these detected internal modes occurred over 0.5 GPa, which is consistent with the proposed phase transition. The evolutions of internal modes vs pressure are shown in Figures 3b−h. The ring deformation modes (406, 537, and 548 cm−1), C−C stretching modes (863 and 950 cm−1), and CC stretching modes (1590 and 1617 cm−1) abruptly shifted to higher frequencies. These shifts indicate that the five-membered ring of the maleic anhydride molecule was suddenly compressed to be smaller in phase II. This phenomenon is due to the decrease in intermolecular distance and enhancements in intermolecular interactions. The CO stretching modes (1747, 1775, 1846, and 1873 cm−1) showed an abrupt blueshift, indicating that CO bonds were shortened during this high-pressure phase transition. Meanwhile, the C−H stretching modes showed an abrupt redshift, indicating that C−H bonds were lengthened during this highpressure phase transition; this phenomenon might be derived from strengthening of intermolecular interactions around C−H bonds or formation of new C−H···O hydrogen bonds.17 The appearance of new external modes in the 50−250 cm−1 region is also supplementary evidence. The CO bending mode (556 cm−1) and the C−H bending mode (762 cm−1) abruptly shifted to higher frequencies, indicating that the intermolecular interaction was enhanced.42,43 These internal modes exhibited smaller shift rates than those of external modes because covalent bonds are more difficult to be compressed than noncovalent bonds because of their higher strength. The Raman results of the released samples in Figure 4 also indicate that the observed transitions are completely reversible. We conducted in situ high-pressure ADXRD experiments to further analyze the phase transition of maleic anhydride. Selected ADXRD patterns of maleic anhydride vs pressure are shown in Figure 5. The emergence of six new peaks (marked by asterisks) with regular blueshifting of the initial peaks at 0.6 GPa indicates that the original crystal structure was changed and the crystalline symmetry was lowered. The Pawley refinement result shown in Figure 6 indicates that phase II may crystallize in the P21/m space group of monoclinic symmetry at 0.6 GPa. The initial crystal structure broke; the

Figure 5. Representative synchrotron XRD patterns of maleic anhydride at high pressures. The new peaks are marked by asterisks.

origin symmetry became lower, and the intrinsic molecular arrangement was altered. The lattice constants can be indexed as the following results: a = 15.25(7), b = 4.98(2), c = 10.14(8) Å, β = 94.25(0)°, and V = 769.22(7) Å3 as the unit cell volume with Z = 8. The second-order Birch−Murnaghan equation was used to fit the unit cell volumes in Figure 7: V0 = 425.36(6) Å3, B0 = 8.15(6) GPa, and B0′ = 4 (fixed) for phase I and V0 = 805.12(6) Å3, B0 = 11.49(6) GPa, and B0′ = 4 (fixed) for phase II. These parameters indicate that the compressibility of the new phase at high pressure is lowered. In addition, the diffraction pattern of the recovered samples returns to that of phase I. This phenomenon indicates that the phase transition was recovered by the released pressure. This finding is consistent with the Raman results. The results of Raman and ADXRD experiments show evident phenomena on the phase transition of maleic anhydride. We used the first-principle calculations to obtain the possible changes in molecular arrangement at higher pressure. The calculated results indicate that this high-pressure transition is associated with the molecular chains of maleic anhydride. As shown in Figure 8, the high-pressure structure is formed mainly by the planarity of molecular arrangement, D


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Figure 6. Pawley refinements of the diffraction patterns collected at 0.6 GPa. Solid lines and asterisks represent the simulated and observed profiles, respectively.

phase transition). The results from the first-principle calculations reveal that, below 0.6 GPa, the neighboring molecules in the maleic anhydride crystal inevitably became closer to each other because of the applied pressure. The closer packing of maleic anhydride molecules made van der Waals interactions (particularly those along the b-axis) strengthened under higher pressures. The tendency of planarity of molecular arrangement resulted in the low compressibility of the b-axis below 0.6 GPa. Consequently, the increase in free energy made the crystal structure and molecular arrangement unstable when the applied pressure was sufficiently high. Thus, phase transition and molecular rearrangement occurred to reduce the total energy and obtain new equilibrium positions. The van der Waals interactions are the primary intermolecular interactions in the maleic anhydride crystal at ambient conditions.21,22 As pressure increased, the molecular packing became closer, which strengthened the van der Waals interactions among maleic anhydride molecules. After being compressed over 0.5 GPa, maleic anhydride no longer withstood the increasing van der Waals interactions. Thus, the five-membered ring shrunk, and several covalent bonds distorted, elongated, or shortened to reduce the strengthening of the van der Waals interactions. A few new intermolecular interactions also occurred. Therefore, all of these changes induced the abrupt transition in crystal structure and molecular rearrangement. The discontinuities of the Raman modes at 0.5 GPa are consistent with the weak distortion and rotation of molecules to accommodate the denser space in phase II. The

Figure 7. Unit cell volume as a function of pressure.

which is parallel to the b-axis. In Figures 9a and b, reduced lattice constants of ADXRD experiments and the geometric optimization both indicate that the a- and c-axes are more compressible than the b-axis below 0.6 GPa (i.e., before the

Figure 8. First-principle calculation results of maleic anhydride: (a) molecular arrangement at ambient pressure and (b) molecular arrangement at high pressure. E


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Figure 9. Reduced lattice constants of ADXRD experiments correspond to those of the calculated results: (a) experimental results and (b) calculated results.

20120061130006), and the Changbai Mountain Scholars Program (Grant 2013007). ADXRD experiments were performed at the Beijing Synchrotron Radiation Facility (4W2 beamline), which is supported by the Chinese Academy of Sciences (Grants KJCX2-SW-N20 and KJCX2-SW-N03).

experimental and calculated results have consistently elucidated that the phase transition was derived from the planarity of molecular arrangement. Maleic anhydride molecules selected a new molecular packing in phase II to avoid this tendency of the planarity of molecular arrangement. After the pressure was released, these deformed molecules were recovered, which induced the return of the high-pressure phase to phase I.

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CONCLUSION We investigated the molecular arrangement and crystal structure of maleic anhydride through in situ high-pressure Raman spectroscopy and ADXRD experiments. The Raman results indicate the occurrence of a pressure-induced phase transition from phase I to II at approximately 0.5 GPa. Moreover, ADXRD results provide further structural details on the high-pressure phase (phase II). The observed experimental results also elucidate that this pressure-induced transition is completely reversible. The calculated results by the firstprinciple method are consistent with the experimental results, clarifying the transition mechanism in terms of the planarity of molecular arrangement. The present study can help provide a better understanding of the changes in intermolecular interactions under high-pressure conditions.

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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.jpcc.6b06351. Assignment of the major Raman bands of maleic anhydride and lattice parameters of maleic anhydride at 0.6 GPa (PDF)

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REFERENCES

(1) DiCiccio, A. M.; Coates, G. W. Ring-Opening Copolymerization of Maleic Anhydride with Epoxides: A Chain-Growth Approach to Unsaturated Polyesters. J. Am. Chem. Soc. 2011, 133, 10724−10727. (2) Centi, G.; Trifiro, F.; Ebner, J. R.; Franchetti, V. M. Mechanistic Aspects of Maleic Anhydride Synthesis from C4 Hydrocarbons over Phosphorus Vanadium Oxide. Chem. Rev. 1988, 88, 55−80. (3) Cordone, R.; Harman, W. D.; Taube, H. π-Heterocyclic Complexes of Pentaammineosmium (II) and the Metal-Induced Cycloaddition of Pyrrole and Maleic Anhydride. J. Am. Chem. Soc. 1989, 111, 5969−5970. (4) Hardham, W. M.; Hammond, G. S. Mechanisms of Photochemical Reactions in Solution. XLIII.1 Addition of Maleic Anhydride to Benzene. J. Am. Chem. Soc. 1967, 89, 3200−3205. (5) Grovenstein, E., Jr.; Rao, D. V.; Taylor, J. W. The Structure and Stereochemistry of the Photochemical Adduct of Benzene with Maleic Anhydride1. J. Am. Chem. Soc. 1961, 83, 1705−1711. (6) Feuer, H.; White, E. H.; Wyman, J. E. The Reactions of Maleic Anhydride with Hydrazine Hydrate1. J. Am. Chem. Soc. 1958, 80, 3790−3792. (7) Craig, D. The Diels-Alder Reactions of the Piperylene Isomers with Maleic Anhydride and Fumaric Acid. J. Am. Chem. Soc. 1950, 72, 1678−1681. (8) Kiselev, V. D.; Shakirova, I. I.; Kornilov, D. A.; Kashaeva, E. A.; Potapova, L. N.; Konovalov, A. I. Studying the Effect of High Pressure on the Cycloaddition Reactions of Maleic Anhydride and Substituted Anthracenes. Russ. J. Phys. Chem. A 2013, 87, 160−162. (9) Kiselev, V. D. High-Pressure Influence on the Rate of Diels− Alder Cycloaddition Reactions of Maleic Anhydride with Some Dienes. Int. J. Chem. Kinet. 2013, 45, 613−622. (10) Goncharov, A. F.; Manaa, M. R.; Zaug, J. M.; Gee, R. H.; Fried, L. E.; Montgomery, W. B. Polymerization of Formic Acid under High Pressure. Phys. Rev. Lett. 2005, 94, 065505. (11) Citroni, M.; Ceppatelli, M.; Bini, R.; Schettino, V. Laser-Induced Selectivity for Dimerization versus Polymerization of Butadiene Under Pressure. Science 2002, 295, 2058−2060. (12) Grochala, W.; Hoffmann, R.; Feng, J.; Ashcroft, N. W. The Chemical Imagination at Work in Very Tight Places. Angew. Chem., Int. Ed. 2007, 46, 3620−3642.

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected], Tel.: 86-431-85168882. *E-mail: [email protected]. 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 (Grant 91227202), RFDP (Grant F


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Detector to Idealised Image or Two-Theta Scan. High Pressure Res. 1996, 14, 235−248. (34) Clark, S. J.; Segall, M. D.; Pickard, C. J.; Hasnip, P. J.; Probert, M. I. J.; Refson, K.; Payne, M. C. First Principles Methods Using CASTEP. Z. Kristallogr. - Cryst. Mater. 2005, 220, 567−570. (35) Duan, D.; Tian, F.; He, Z.; Meng, X.; Wang, L.; Chen, C.; Zhao, X.; Liu, B.; Cui, T. Hydrogen Bond Symmetrization and Superconducting Phase of HBr and HCl under High Pressure: an Ab Initio Study. J. Chem. Phys. 2010, 133, 074509. (36) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865−3868. (37) Vanderbilt, D. Soft Self-Consistent Pseudopotentials in a Generalized Eigenvalue Formalism. Phys. Rev. B: Condens. Matter Mater. Phys. 1990, 41, 7892−7895. (38) Mirone, P.; Chiorboli, P. Infrared and Raman Spectra and Vibrational Assignment of Maleic Anhydride. Spectrochim. Acta 1962, 18, 1425−1432. (39) Ishibashi, Y.; Shimada, R.; Shimada, H. Polarized Raman Spectrum of Maleic Anhydride Crystal. Bull. Chem. Soc. Jpn. 1982, 55, 2765−2770. (40) Park, T.-R.; Dreger, Z. A.; Gupta, Y. M. Raman Spectroscopy of Pentaerythritol Single Crystals under High Pressures. J. Phys. Chem. B 2004, 108, 3174−3184. (41) Ciezak, J. A.; Jenkins, T. A.; Liu, Z.; Hemley, R. J. High-Pressure Vibrational Spectroscopy of Energetic Materials: Hexahydro-1,3,5trinitro-1,3,5-triazine. J. Phys. Chem. A 2007, 111, 59−63. (42) Franco, O.; Orgzall, I.; Regenstein, W.; Schulz, B. Structural and Spectroscopical Study of a 2,5-Diphenyl-1, 3, 4-oxadiazole Polymorph under Compression. J. Phys.: Condens. Matter 2006, 18, 1459−1472. (43) Rao, R.; Sakuntala, T.; Godwal, B. Evidence for High-Pressure Polymorphism in Resorcinol. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 054108.

(13) Ciabini, L.; Santoro, M.; Gorelli, F. A.; Bini, R.; Schettino, V.; Raugei, S. Triggering Dynamics of the High-Pressure Benzene Amorphization. Nat. Mater. 2007, 6, 39−43. (14) Coronado, E.; Giménez-López, M. C.; Korzeniak, T.; Levchenko, G.; Romero, F. M.; Segura, A.; García-Baonza, V.; Cezar, J. C.; de Groot, F. M. F.; Milner, A.; et al. Pressure-Induced Magnetic Switching and Linkage Isomerism in K0.4Fe4[Cr(CN)6]2.8 · 16H2O: X-ray Absorption and Magnetic Circular Dichroism Studies. J. Am. Chem. Soc. 2008, 130, 15519−15532. (15) Boldyreva, E. V. High-pressure studies of the anisotropy of structural distortion of molecular crystals. J. Mol. Struct. 2003, 647, 159−179. (16) Mito, M.; Komorida, Y.; Tsuruda, H.; Tse, J. S.; Desgreniers, S.; Ohishi, Y.; Leitch, A. A.; Cvrkalj, K.; Robertson, C. M.; Oakley, R. T. Heavy Atom Ferromagnets under Pressure: Structural Changes and the Magnetic Response. J. Am. Chem. Soc. 2009, 131, 16012−16013. (17) Murli, C.; Lu, N.; Dong, Z.; Song, Y. Hydrogen Bonds and Conformations in Ethylene Glycol under Pressure. J. Phys. Chem. B 2012, 116, 12574−12580. (18) Marciniak, J.; Bąkowicz, J.; Dobrowolski, M. A.; Dziubek, K. F.; Kaźmierczak, M.; Paliwoda, D.; Rajewski, K. W.; Sobczak, S.; Stachowicz, M.; Katrusiak, A. Most Frequent Organic Interactions Compressed in Toluene. Cryst. Growth Des. 2016, 16, 1435−1441. (19) Patyk, E.; Podsiadło, M.; Katrusiak, A. CH···N Bonds and Dynamics in Isostructural Pyrimidine Polymorphs. Cryst. Growth Des. 2015, 15, 4039−4044. (20) Dai, Y.; Wang, K.; Zhou, B.; Du, M.; Liu, R.; Liu, B.; Zou, B. Gauche−trans Conformational Equilibrium of Succinonitrile under High Pressure. J. Phys. Chem. C 2016, 120, 5340−5346. (21) Marsh, R. E.; Ubell, E.; Wilcox, H. E. The Crystal Structure of Maleic Anhydride. Acta Crystallogr. 1962, 15, 35−41. (22) Lutz, M. Maleic Anhydride, Redetermination at 130 K. Acta Crystallogr., Sect. E: Struct. Rep. Online 2001, 57, o1136−o1138. (23) Johnson, E. R.; Keinan, S.; Mori-Sánchez, P.; Contreras-García, J.; Cohen, A. J.; Yang, W. Revealing Noncovalent Interactions. J. Am. Chem. Soc. 2010, 132, 6498−6506. (24) Orgzall, I.; Emmerling, F.; Schulz, B.; Franco, O. High-Pressure Studies on Molecular CrystalsRelations between Structure and High-Pressure Behavior. J. Phys.: Condens. Matter 2008, 20, 295206. (25) Cai, W.; Gładysiak, A.; Anioła, M.; Smith, V. J.; Barbour, L. J.; Katrusiak, A. Giant Negative Area Compressibility Tunable in a Soft Porous Framework Material. J. Am. Chem. Soc. 2015, 137, 9296−9301. (26) Fabbiani, F. P. A.; Pulham, C. R. High-Pressure Studies of Pharmaceutical Compounds and Energetic Materials. Chem. Soc. Rev. 2006, 35, 932−942. (27) Fitzgibbons, T. C.; Guthrie, M.; Xu, E.; Crespi, V. H.; Davidowski, S. K.; Cody, G. D.; Alem, N.; Badding, J. V. BenzeneDerived Carbon Nanothreads. Nat. Mater. 2014, 14, 43−47. (28) Santoro, M.; Gorelli, F. A.; Bini, R.; Haines, J.; Van Der Lee, A. High-Pressure Synthesis of a Polyethylene/Zeolite Nano-Composite Material. Nat. Commun. 2013, 4, 1557. (29) Wilhelm, C.; Boyd, S. A.; Chawda, S.; Fowler, F. W.; Goroff, N. S.; Halada, G. P.; Grey, C. P.; Lauher, J. W.; Luo, L.; Martin, C. D.; Parise, J. B.; Tarabrella, C.; Webb, J. A. Pressure-Induced Polymerization of Diiodobutadiyne in Assembled Cocrystals. J. Am. Chem. Soc. 2008, 130, 4415−4420. (30) Wang, K.; Liu, J.; Yang, K.; Liu, B.; Zou, B. High-PressureInduced Polymorphic Transformation of Maleic Hydrazide. J. Phys. Chem. C 2014, 118, 8122−8127. (31) Dai, Y.; Wang, K.; Yuan, H.; Meng, X.; Luo, K.; Yu, D.; Liu, J.; Zhang, X.; Ma, Y.; Tian, Y.; et al. Selected Reactive Sites Tuned by High Pressure: Oligomerization of Solid-State Cyanamide. J. Phys. Chem. C 2015, 119, 12801−12807. (32) Mao, H. K.; Bell, P. M.; Shaner, J. W.; Steinberg, D. J. Specific Volume Measurements of Cu, Mo, Pd, and Ag and Calibration of the Ruby R1 Fluorescence Pressure Gauge from 0.06 to 1 Mbar. J. Appl. Phys. 1978, 49, 3276−3283. (33) Hammersley, A.; Svensson, S.; Hanfland, M.; Fitch, A.; Hausermann, D. Two-Dimensional Detector Software: From Real G


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