Hydrogen Bonding Network: Stabilization of the Pentazolate Anion in

Subscriber access provided by EKU Libraries

Article

Hydrogen Bonding Network: Stabilization of the Pentazolate Anion in Two Nonmetallic Energetic Salts Yuangang Xu, Lili Tian, Pengcheng Wang, Qiuhan Lin, and Ming Lu Cryst. Growth Des., Just Accepted Manuscript • Publication Date (Web): 22 Jan 2019 Downloaded from http://pubs.acs.org on January 23, 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 30 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

Hydrogen Bonding Network: Stabilization of the Pentazolate Anion in Two Nonmetallic Energetic Salts Yuangang Xu, Lili Tian, Pengcheng Wang,* Qiuhan Lin, and Ming Lu* School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China

ABSTRACT: Pentazolate anion (cyclo-N5−) containing compounds have attracted wide interest in recent years. In this work, we report the new syntheses, single-crystal structures, and thermal stabilities of two nonmetallic salts (C4H9N10+)(N5−)·3H2O (4) and (C5H9N10+)2(Cl−)(N5−)·3.5H2O (5). Single crystal X-ray diffraction shows that compound 4 and 5 have layer-by-layer stacking and three-dimensional (3D) structures constructed by hydrogen bonding networks, in which the 2D and 3D hydrogen bonding networks are formed to stabilize cyclo-N5− anions. The two cycloN5− salts are stable at room temperature and thermal analyses indicate their onset decomposition temperatures of 95.35 oC for 4 and 98.52 oC for 5. Hirshfeld surface analyses showed that the following factors could improve the thermal stability of cyclo-N5−: N-H…N hydrogen bonds are better than O-H…N hydrogen bonds; 3D hydrogen bonding network is superior to 2D hydrogen bonding network. These findings will enhance the future prospects for the design and synthesis of cyclo-N5− containing energetic salts.

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 30

■ INTRODUCTION Polynitrogen containing compounds have attracted wide interest because of their unique structures and potential applications in the field of high-energy-density materials (HEDMs). In spite of different kinds of theoretical predictions, for a long time, only dinitrogen (N2) and the azide anion (N3−) can be prepared on a macroscopic scale. Until 1999, the syntheses of stable pentanitrogen cation (N5+) salts

1-4

have actually demonstrated the feasibility of pursuing

polynitrogen-containing materials in experiments. Then, at very high pressures (>120 GPa) and temperatures (>2000 K), polymeric cubic-gauche (cg)

5

and layered

6

phases of nitrogen were

synthesized. However, they are metastable at pressures down to 40 GPa and further their quenching to ambient conditions is problematic. In recent years, great progress has been made in this field. A transformation from insulating (molecular) to conducting dense fluid nitrogen was observed above 125 GPa at 2500 K (very high pressure and temperature) and the metallic fluid N above 125 GPa was likely produced by melting of metastable bulk η nitrogen7 (Figure 1). Highpressure/high-temperature experiments guided by first-principles crystal structure prediction were used to synthesize cesium pentazolate salt (CsN5), the first solid state compound consisting of pentazolate anion (cyclo-N5−)8 (Figure 1). CsN5 was achieved by compressing and laser heating cesium azide (CsN3) mixed with N2 cryogenic liquid in a diamond anvil cell (DAC). The stability of the cyclo-N5− is mainly due to the ionic bonds and aromaticity formed by the electron transfer from Cs ions to cyclo-N5− rings. Similar to the synthesis of CsN5, LiN5

9

and CuN5

10

were reported in succession. Under relatively mild conditions (0.1 MPa, 230K), salts of cycloN5−

11,12

was synthesized through cleavage of C-N bond in substituted pentazole by ferrous

bisglycinate Fe(Gly)2 and m-chloro-perbenzoic-acid (m-CPBA) (Figure 1). And a series of cycloN5−

based

complexes

12,13

[Mn(H2O)4(N5)2]·4H2O,

[Fe(H2O)4(N5)2]·4H2O,


Page 3 of 30 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


[Co(H2O)4(N5)2]·4H2O, [Zn(H2O)4(N5)2]·4H2O, and [Mg(H2O)6(N5)2]·4H2O; frameworks [Na(H2O)(N5)]·2H2O, [NaBa3(N5)6(NO3)(H2O)3]n,

[Na8(N5)8(H2O)3]n, [Cu(N5)(N3)]n,

MPF-1, [Ag(N5)]n,

[Ag(NH3)2]+[Ag3(N5)4]−; and coordination polymers

19

12,14-18

[Ba(N5)(NO3)(H2O)3]n,

[LiNa(N5)2(H2O)4]·H2O,

and

(NaN5)5[(CH6N3)N5](N5)3− and

(NaN5)2(C2H4N4) were reported later. However, the synthesis of nonmetallic energetic salts of cyclo-N5− is a big challenge. In our continuing efforts to synthesize new cyclo-N5− containing materials, DABTT2+(N5−)2, Gu+N5−, and Oxahy+N5− were synthesized and isolated by our group

20

. Here we present the

syntheses of two new nonmetallic salts of cyclo-N5− and their 3D structures constructed by hydrogen bonding networks as well as thermal analyses.

Figure 1. Recent progresses of polynitrogen containing compounds.



Page 4 of 30

■ SYNTHESIS The synthetic pathway is shown in Scheme 1. Compound 4,4’,5,5’-tetraamino-3,3’-bi-1,2,4triazole (1) was prepared according to the reported methods

21,22

. 3,9-diamino-6,7-dihydro-5H-

bis([1,2,4]triazolo)[4,3-e:3’,4’-g][1,2,4,5] tetrazepine-2,10-diium chloride (2) was prepared according

to

our

previous

work

23

.

6,7-dihydro-5H-bis([1,2,4]triazolo)[4,3-e:3’,4’-

g][1,2,4,5]tetrazepine-3,9-diamine (C5H8N10, 3) can be obtained by neutralization dihydrochloride 2 with two equivalent sodium bicarbonate (NaHCO3). Compound 1 was treated with one equivalent 37 % hydrochloric acid (HCl) and [Na(H2O)(N5)]·2H2O to obtain 4,4’,5,5’tetraamino-4H,4’H-[3,3’-bi(1,2,4-triazol)]-1-ium pentazolate·3H2O ((C4H9N10+)(N5−)·3H2O, 4). Using a similar method, (C5H9N10+)2(Cl−)(N5−)·3.5H2O (5) was obtained from 3. Here, the protonation and metathesis reaction can occur in one pot. Compared with our previous method 20, this method is more simple and efficient. Scheme 1. Synthesis of 4 and 5


Page 5 of 30 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


■ STRUCTURE DISCUSSIONS Compound 3 has a very poor solubility in organic solvents. So the smallest amount of hydrochloric acid was added to the suspension of 3 in distilled water to get a clear solution. It was

then

slowly

evaporating

(C5H8N10)(C5H9N10+)(Cl−)·4H2O

at that

room

temperature

contains

3

to as

obtain a

single neutral

crystals

of

component.

(C5H8N10)(C5H9N10+)(Cl−)·4H2O (Figure 2a) crystallizes in the triclinic space group P-1 with two molecules in the unit cell with a calculated density of 1.38 g cm-3 at 296.15 K. Both protonated and unprotonated 3 are trans structures with the torsion angles of 3.59o (C3-C4-N6-N7) and 2.70o (C7-C6-N16-N17). The packing diagram was shown in the Figure 2b and Figure S1, the face-to-face crystal packing (layer-by-layer stacking) further constructs the 3D structure by numerous hydrogen bonds between adjacent layers.

Figure 2. (a) Crystal structure of (C5H8N10)(C5H9N10+)(Cl−)·4H2O; thermal ellipsoids are drawn at the 50% probability level. (b) The 3D structure of (C5H8N10)(C5H9N10+)(Cl−)·4H2O constructed by hydrogen bonding networks. Dashed lines indicate strong hydrogen bonding.



Page 6 of 30

Figure 3. (a) Crystal structure of 4; thermal ellipsoids are drawn at the 50% probability level. (b) Hydrogen bonds around cyclo-N5− in 4. (c) 2D layered intermolecular interactions in the crystal structure of 4. (d) The 3D structure of 4 constructed by hydrogen bonding networks. Dashed lines indicate strong hydrogen bonding. HBs: hydrogen bonds. Compound 4 (Figure 3a) crystallizes in the triclinic space group P-1 with a density of 1.520 g cm-3 at 173 K. The N-N bond lengths in cyclo-N5− are 1.309, 1.313, 1.313, 1.319, and 1.322 Å; the average N-N bond distance (1.3152 Å) is shorter than that of most reported cyclo-N5− based crystals 11-20. Unlikely most reported complexes, cyclo-N5- ring in 4 lacks perfect planarity, with the largest torsion angle (N13-N11-N12-N15) of 0.64o which is shorter than that of [Mg(H2O)6(N5)2]·4H2O (0.85o) 12. The C4H9N10+ cations and the corresponding cyclo-N5¯ anions are almost coplanar with torsion angles of 170.99o (N13-N12-N11-N7), 178.70o (N14-N11-N15N10), and 174.31o (N15-N12-N11-N8). Each cyclo-N5− anion was stabilized by four hydrogen bonds (2.782-2.936 Å) from four water molecules and one hydrogen bond (3.103 Å) from a C4H9N10+ cation (Figure 3b). The lengths of the hydrogen bonds are shorter than the sum of the


Page 7 of 30 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


van der Waals (vdW) radii (rw(N) + rw(N) = 3.20 Å; rw(N) + rw(O) = 3.10 Å), thus a strong hydrogen-bond network (2D) is formed along the ac plane (Figure 3c). We can see from Figure 3d, the crystal is layer-by-layer stacking and the interlayer distance is 3.42 Å. The adjacent layers are connected by two kinds of hydrogen bonds (O2--O3 HBs and O1--N1 HBs), the details are shown in the Figure S2. It is important to note that coordinated water molecules have played multiple effects in the hydrogen bonding network including: 1) to stabilize cyclo-N5− anions through hydrogen bonds; 2) to stabilize the 2D layered structure; and 3) to build the hydrogen bond network among the adjacent layers.

Figure 4. (a) Crystal structure of 5; thermal ellipsoids are drawn at the 50% probability level. (b) Hydrogen bonds around cyclo-N5− in 5. (c) 2D layered intermolecular interactions in the crystal structure of 5. (d) The 3D structure of 5 constructed by hydrogen bonding networks. Dashed lines indicate strong hydrogen bonding.



Page 8 of 30

Compound 5 crystallizes from water in the triclinic space group P-1 with a density of 1.617 g cm-3 at 173 K and four fused C5H9N10+ cations, two Cl−, two cyclo-N5−, and seven water moieties per unit cell. The molecular unit of 5 is shown in Figure 4a. The N-N bond lengths in cyclo-N5are 1.288, 1.305, 1.308, 1.310, and 1.312 Å; the average N-N bond distance (1.305 Å) is shorter than that of 4 and all the reported cyclo-N5− based crystals

11-20

. Because of the strong aromatic

nature of the bond in the cyclo-N5− ring, the bond lengths for cyclo-N5− in 5 are between that of the double-bond (1.25 Å as in trans-diimine) and the single bond (1.45 Å as in hydrazine) and closer to the double bond. Cyclo-N5− ring in 5 has the largest torsion angle (N22-N23-N24-N25) of 0.26o which is shorter than that of 4. The N-N bond lengths (1.390(3) and 1.396(3) Å) of the the unprotonated 1,2,4-triazoles is slightly longer than those of the protonated triazoles (1.382(3) Å). All the amino groups participate in hydrogen bonds act as donors, whereas in the two fused cations only N3, N9, N11, N12, and N18 act as hydrogen-bond acceptors (Table S13). Unlike each nitrogen of cyclo-N5− is hydrogen bonded almost at a plane in 4, cyclo-N5− in 5 is hydrogen bonded by five C5H9N10+ cations from three layers and three water molecules (Figure 4b) and more hydrogen bonds are formed. However, numerous hydrogen bonds around cyclo-N5− can be seen from the b-axis (ac plane) of the packing diagram. There are also many hydrogen bonds on the bc plane (Figure 4c). The lengths of the hydrogen bonds are shorter than the sum of the vdW radii (rw(N) + rw(N) = 3.20 Å; rw(N) + rw(O) = 3.10 Å; rw(N) + rw(Cl) = 3.40 Å), thus a strong hydrogen-bond network is formed (Table S13). The interlayer distance in 5 is 3.32 Å (Figure 4d), which is slightly shorter than that of 4 (3.42 Å). To obtain a better understanding of the weak interactions between cyclo-N5− and corresponding cations in 4 and 5, noncovalent interaction (NCI) anaylsis was performed by Multiwfn

24

. The results are shown in the Figure 5. From the color-filled reduced density


Page 9 of 30 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


gradient (RDG) isosurface, we can identify different type of regions by simply examining their colors (Figure 5a, b). According to the default settings, the more blue implies the stronger attractive interaction; it can be seen that the elliptical slabs between nitrogen atoms from cycloN5− rings and hydrogen atoms from amino groups show light blue color, so we can conclude that there are hydrogen bonds, but not very strong. From their scatter graphs (Figure 5c, d) we know the N-H…N hydrogen bonds in 5 are stronger than those in 4. The interaction region marked by green circle in Figure 5c can be identified as vdW interaction region, because the mapped color is green or light brown, which exhibits that the density electron in this region is low. The π-π interactions in 4 are more obvious than those in 5. They exist between cyclo-N5− rings and cations as well as two C4H9N10+ cations in 4. Obviously, the regions in the center of cyclo-N5− and other rings show steric effect, since they are filled by red.



Page 10 of 30

Figure 5. (a, b) Noncovalent interactions analyses, including hydrogen bonds and π-π interactions for 4 and 5 (blue: strong attraction; green: weak interaction; red: strong repulsion). (c, d) Scatter graphs for 4 and 5. ■ ENERGETIC PROPERTIES According to our previous work, 20 the energetic cyclo-N5− salt DABTT2+(N5−)2 (DABTT2+ = C5H10N102+) which has the similar fused cation with 5 ((C5H9N10+)2(Cl−)(N5−)·3.5H2O) has a density of 1.629 g cm-3, a heat of formation of 1341 kJ mol-1, and detonation velocity (D) of 7615 m s-1, detonation pressure (P) of 23.6 GPa. To evaluate if anhydrous salt of 4 (C4H9N10+)(N5−) has potential as an energetic material, its density, heat of formation, as well as detonation performances (D and P) have been predicted. Its density was obtained using an improved equation proposed by Politzer et al. considering intermolecular interactions within the crystal

25

to be 1.624 g cm-3, which is slightly lower than that of DABTT2+(N5−)2. The heat of

formation was calculated by using the Guassian 09 (Revision A.02) suite of programs

26

. It is

obvious that the anhydrous salt of 4 possesses a very high heat of formation (1059 kJ mol-1) originated from the inherently energetic C-N and N-N bonds. The detonation performances of the anhydrous salt of 4 was calculated using the Explo5 program (version 6.01)

27

. The results

showed that (C4H9N10+)(N5−) display relatively higher D (7741 m s-1) and P (24.8 GPa) than TNT and DABTT2+(N5−)2. ■ STABILITY DISCUSSIONS The thermal stabilities of 4 and 5 are evaluated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analyses. From the DSC and TG curves in Figure 6 and S6, two endothermic peaks and two exothermic peaks were observed for 4 and 5. The two endothermic


Page 11 of 30 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


peaks indicate the escaping of water molecules. The first exothermic peak (4: 112.23 oC; 5: 124.43 oC) means the thermal decomposition of cyclo-N5− with about 100 J g-1 heat release (4: 109.94 J g-1; 5: 95.32 J g-1). At the second endothermic stage, larger peaks were observed at 371.74 and 253.32 oC, extremely due to the decomposition of C4H9N10+N3− and C5H9N10+N3−.

Figure 6. DSC curves of 4 and 5 at a heating rate of 5 oC min-1.



Page 12 of 30

Figure 7. (a-c) Hirshfeld surfaces of cyclo-N5− in 4. (d) The pie graph for individual atomic contacts percentage contribution to the Hirshfeld surface. (e) Tow-dimensional fingerprint plot in crystal staking for cyclo-N5− in 4. (f) Broken down into contributions from specific pair of atomtype (N-H). We notice that the cyclo-N5− anions in 5 (Tdec, onset = 98.52) are more stable than those in 4 (Tdec, onset

= 95.35). With the aim of gaining a deep insight into the stability of cyclo-N5−, Hirshfeld

surfaces and 2D fingerprint spectra of cyclo-N5− in 4 and 5 were studied to show intramolecular contacts between cyclo-N5− and other components 28. As shown in Figure 7 and 8, only a single remarkable spike on bottom left (N--H interactions) in the 2D fingerprint spectra of cyclo-N5− in both crystals. The thick spike of cyclo-N5− in 5 indicates that more hydrogen bonds are observed which is in agreement with our previous discussions. In Figure 7d and 8d, the individual atomic


Page 13 of 30 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


contacts percentage contribution also confirmed the conclusion, in which N--H possesses 86.6 % of total weak interactions for 4 and 93.4 % for 5. The difference is that O-H…N hydrogen bonds contribute to most of the N--H interactions of cyclo-N5− in 4, however N-H…N hydrogen bonds contribute most in 5. In addition, the shorter di+de of the spike suggest slightly stronger hydrogen-bonds in 4. (d)

(a)

e a

d b

(e)

c

N--N

N--O

(b)

(c) b a

e

d

c

Figure 8. (a-c) Hirshfeld surfaces of cyclo-N5− in 5. (d) The pie graph for individual atomic contacts percentage contribution to the Hirshfeld surface. (e) Tow-dimensional fingerprint plot in crystal staking for cyclo-N5− in 5. According to the results of the Hirshfeld surfaces analyses combined with the bond lengths of the cyclo-N5− ring, we speculate that different kinds of hydrogen bonds in the nonmetallic salts will lead to different extensions of cyclo-N5− ring due to their different bond energies, thus



Page 14 of 30

affecting the bond length of cyclo-N5− ring, thereby affecting the thermal stability of cyclo-N5− ring. Therefore, N-H...N hydrogen bonds are more beneficial to the stability of the cyclo-N5− ring than O-H...N hydrogen bonds, and even in the future the cyclo-N5− based ionic salts can be synthesized with only C-H…N hydrogen bonds in the molecules. This indicates the existence of more kinds of anhydrous nonmetallic salts containing cyclo-N5−. In addition, more hydrogen bonds outside the plane of the cyclo-N5−, that is, a 3D hydrogen bond network, may be more likely to improve the thermal stability of cyclo-N5− than a 2D hydrogen bond network. ■ CONCLUSION In summary, two new polynitrogen containing nonmetallic salts (C4H9N10+)(N5−)·3H2O (4) and (C5H9N10+)2(Cl−)(N5−)·3.5H2O (5) were designed and synthesized by a new method. Compounds 4 and 5 all have layer-by-layer stacking and hydrogen bonding networks (2D or 3D) to stabilize cyclo-N5− anions. Thermal analyses indicate that the stability of cyclo-N5− in 4 is 95.35 oC (onset decomposition temperature) which is lower than that in 5 (98.52 oC). Hirshfeld surfaces analyses show N-H...N hydrogen bonds are more beneficial to the stability of the cyclo-N5− ring than OH...N hydrogen bonds, and the 3D hydrogen bond network may be more likely to improve the thermal stability of cyclo-N5− than a 2D hydrogen bond network. This work opens the door to explore more kinds of anhydrous nonmetallic salts containing cyclo-N5−. ■ ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.cgd.xxxxxxx.


Page 15 of 30 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


Safety precautions, general analysis methods, synthetic procedures, details of X-ray crystallography, TG curves, and IR spectra (PDF). Accession Codes CCDC 1556907, 1589207, and 1874758 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033. ■ AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected]. *E-mail: [email protected]. ORCID Yuangang Xu: 0000-0002-6504-4405 Ming Lu: 0000-0003-3007-7773 Author Contributions Y. Xu and M. Lu designed and engineered the experiments; Y. Xu performed the experiments, analyzed the data and wrote the paper with support from L. Tian, P. Wang and Q. Lin. All authors contributed to the general discussion. Notes



Page 16 of 30

The authors declare no competing financial interest. ■ ACKNOWLEDGMENT Financial support of the National Natural Science Foundation of China (No. 21771108, 11702141, U1530101) is greatly acknowledged. We thank Mr. Zaiyong Zhang (Shanghai Institute of Materia Medica) for analysis of the crystal structures and Mr. Dongjing Hong (College of Chemistry, Nankai University) for re-refining the crystal structures. ■ REFERENCES (1) Christe K. O.; Wilson W. W.; Sheehy J. A.; Boatz J. A. N5+: a novel homoleptic polynitrogen ion as a high energy density material. Angew. Chem. Int. Ed. 1999, 38, 2004-2009. (2) Vij A.; Wilson W. W.; Vij V.; Tham F. S.; Sheehy J. A.; Christe K. O. Polynitrogen chemistry.

Synthesis,

characterization,

and

crystal

structure

of

surprisingly

stable

fluoroantimonate salts of N5+. J. Am. Chem. Soc. 2001, 123, 6308-6313. (3) Wilson W.W.; Vij A.; Vij V.; Bernhardt E.; Christe K. O. Polynitrogen Chemistry: preparation and characterization of (N5)2SnF6, N5SnF5, and N5B(CF3)4. Chem. -Eur. J. 2003, 9, 2840-2844. (4) Haiges R.; Schneider S.; Schroer T.; Christe K. O. High-energy-density materials: synthesis and characterization of N5+[P(N3)6]-, N5+[B(N3)4]-, N5+[HF2]-·nHF, N5+[BF4]-, N5+[PF6]-, and N5+[SO3F]-. Angew. Chem. Int. Ed. 1999, 38, 2004-2009. (5) Eremets M. I.; Gavriliuk A. G.; Trojan I. A.; Dzivenko D. A.; Boehler R. Single-bonded cubic form of nitrogen. Nat. Mater. 2004, 3, 558-563.


Page 17 of 30 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


(6) Tomasino D.; Kim M.; Smith J.; Yoo C. S. Pressure-induced symmetry lowering transition in dense nitrogen to layered polymeric nitrogen (LP-N) with colossal raman intensity. Phys. Rev. Lett. 2014, 113, 205502. (7) Jiang S.; Holtgrewe N.; Lobanov S. S.; Su F.; Mahmood M. F.; McWilliams R. S.; Goncharov A. F. Metallization and molecular dissociation of dense fluid nitrogen. Nat. commun. 2018, 9, 2624. (8) Steele B. A.; Stavrou E.; Crowhurst J. C.; Zaug J. M.; Prakapenka V. B.; Oleynik I. I. High-pressure synthesis of a pentazolate salt. Chem. Mater. 2017, 29, 735-741. (9) Laniel D.; Weck G.; Gaiffe G.; Garbarino G.; Loubeyre P. High-pressure synthesized lithium pentazolate compound metastable under ambient conditions. J. Phys. Chem. Lett. 2018, 9, 1600-1604. (10) Li J.; Sun L.; Wang X.; Zhu H.; Miao M. Simple route to metal cyclo-N5− salt: highpressure synthesis of CuN5. J. Phys. Chem. C 2018, 122, 22339-22344. (11) Zhang C.; Sun C.; Hu B.; Yu C.; Lu M. Synthesis and characterization of the pentazolate anion cyclo-N5− in (N5)6(H3O)3(NH4)4Cl. Science 2017, 355, 374-376. (12) Xu Y.; Wang Q.; Shen C.; Lin Q.; Wang P.; Lu M. A series of energetic metal pentazolate hydrates. Nature 2017, 549, 78-81. (13) Xu Y.; Wang P.; Lin Q.; Lu M. A carbon-free inorganic-metal complex consisting of an all-nitrogen pentazole anion, a Zn(II) cation and H2O. Dalton Trans. 2017, 46, 14088-14093.



Page 18 of 30

(14) Xu Y.; Wang P.; Lin Q.; Mei X.; Lu M. Self-assembled energetic 3D metal-organic framework [Na8(N5)8(H2O)3]n based on cyclo-N5−. Dalton Trans. 2018, 47, 1398-1401. (15) Zhang W.; Wang K.; Li J.; Lin Z.; Song S.; Huang S.; Liu Y.; Nie F.; Zhang Q. Stabilization of the pentazolate anion in a zeolitic architecture with Na20N60 and Na24N60 nanocages. Angew. Chem. Int. Ed. 2018, 57, 2592-2595. (16) Xu Y.; Lin Q.; Wang P.; Lu M. Syntheses, crystal structures and properties of a series of 3D metal-inorganic frameworks containing pentazolate anion. Chem. -Asian J. 2018, 13, 16691673. (17) Li J.; Wang K.; Song S.; Qi X.; Zhang W.; Deng M.; Zhang Q. [LiNa(N5)2(H2O)4]·H2O: a novel heterometallic cyclo-N5− framework with helical chains. Sci. China Mater. 2018, DOI: 10.1007/s40843-018-9335-9. (18) Sun C.; Zhang C.; Jiang C.; Yang C.; Du Y.; Zhao Y.; Hu B.; Zheng Z.; Christe K. O. Synthesis of AgN5 and its extended 3D energetic framework. Nat. commun. 2018, 9, 1269. (19) Wang P.; Xu Y.; Wang Q.; Shao Y.; Lin Q.; Lu M. Self-assembled energetic coordination polymers based on multidentate pentazole cyclo-N5−. Sci. China Mater. 2018, DOI: 10.1007/s40843-018-9268-0. (20) Xu Y.; Lin Q.; Wang P.; Lu M. Stabilization of the pentazolate anion in three anhydrous and metal-free energetic salts. Chem -Asian J 2018, 13, 924-928. (21) Centore R.; Carella A.; Fusco S. Supramolecular synthons in fluorinated and nitrogen-rich ortho-diaminotriazoles. Struct. Chem. 2011, 22, 1095-1103.


Page 19 of 30 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


(22) Centore R.; Fusco S.; Capobianco A.; Piccialli V.; Zaccaria S.; Peluso A. Tautomerism in the fused N-rich tri-azolotriazole heterocyclic system. Eur. J. Org. Chem. 2013, 3721-3728. (23) Xu Y.; Zhu Z.; Shen C.; Lin Q.; Lu M. In situ synthesized energetic salts based on the CN fused tricyclic 3,9-diamine-6,7-dihydro-bis(triazolo)-tetrazepine cation: a family of highperformance energetic materials. Propellants Explos. Pyrotech. 2018, 43, 595-601. (24) Lu T.; ChenF. Multiwfn: a multifunctional wavefunction analyzer. J. Comput. Chem. 2012, 33, 580-592. (25) Politzer P.; Martinez J.; Murray J. S.; Concha M. C.; Toro-Labbé A. An electrostatic interaction correction for improved crystal density prediction. Mol. Phys. 2009, 107, 2095-2101. (26) Frisch M. J.; Trucks G. W.; Schlegel H. B.; Scuseria G. E.; Robb M. A.; Cheeseman J. R.; Scalmani G.; Barone V.; Mennucci B.; Petersson G. A.; Nakatsuji H.; Caricato M.; Li X.; Hratchian H. P.; Izmaylov A. F.; Bloino J.; Zheng G.; Sonnenberg J. L.; Hada M.; Ehara M.; Toyota K.; Fukuda R.; Hasegawa J.; Ishida M.; Nakajima T.; Honda Y.; Kitao O.; Nakai H.; Vreven T.; Montgomery J. A.; Jr.; Peralta J. E.; Ogliaro F.; Bearpark M.; Heyd J. J.; Brothers E.; Kudin K. N.; Staroverov V. N.; Kobayashi R.; Normand J.; Raghavachari K.; Rendell A.; Burant J. C.; Iyengar S. S.; Tomasi J.; Cossi M.; Rega N.; Millam J. M.; Klene M.; Knox J. E.; Cross J. B.; Bakken V.; Adamo C.; Jaramillo J.; Gomperts R.; Stratmann R. E.; Yazyev O.; Austin A. J.; Cammi R.; Pomelli C.; Ochterski J. W.; Martin R. L.; Morokuma K.; Zakrzewski V. G.; Voth G. A.; Salvador P.; Dannenberg J. J.; Dapprich S.; Daniels A. D.; Farkas O.; Foresman J. B.; Ortiz J. V.; Cioslowski J.; Fox D. J. Gaussian 09, revision A.02; Gaussian, Inc.: Wallingford CT, 2009. (27) Sućeska, M. EXPLO5 version 6.01; Brodarski Institute: Zagreb, Croatia, 2013.



Page 20 of 30

(28) Turner M. J.; McKinnon J. J.; Wolff S. K.; Grimwood D. J.; Spackman P. R.; Jayatilaka D.;

Spackman

M.

A.

CrystalExplorer17,

University

of

Western

Australia.

http://hirshfeldsurface.net, 2017.


Page 21 of 30 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


For Table of Contents Use Only: Hydrogen Bonding Network: Stabilization of the Pentazolate Anion in Two Nonmetallic Energetic Salts Yuangang Xu, Lili Tian, Pengcheng Wang,* Qiuhan Lin, and Ming Lu*

Two new pentazolate anion containing nonmetallic salts (C4H9N10+)(N5−)·3H2O and (C5H9N10+)2(Cl−)(N5−)·3.5H2O were designed and synthesized by a new method. They all have layer-by-layer stacking and hydrogen bonding networks (2D or 3D) to stabilize cyclo-N5− anions.



Figure 1 224x162mm (300 x 300 DPI)

ACS Paragon Plus Environment

Page 22 of 30

Page 23 of 30 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 262x83mm (300 x 300 DPI)



Figure 3 269x131mm (300 x 300 DPI)


Page 24 of 30

Page 25 of 30 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 4 354x194mm (300 x 300 DPI)



Figure 5 267x182mm (300 x 300 DPI)


Page 26 of 30

Page 27 of 30

exo

5 o

* 371.74 C

o

253.32 C *

Heat flow

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


4 o

124.43 C * 95.32 J g

-1

* 77.29 oC * o 52.94 C

o

* o

* 53.69 C 50

100

112.23 C 109.94 J g 150

-1

200

250

300 o

Temperature ( C)


350

400

450


Figure 7 245x174mm (300 x 300 DPI)


Page 28 of 30

Page 29 of 30 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 8 244x166mm (300 x 300 DPI)


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

H2N N N

N N

N

H2N

NH2

N

CH2O HCl

Cl

NH2

N N H2N

N

NH N

NH2

NaHCO3

H2N

N NH Cl

HN N

HN N

NH N

NH2

N N

N N

3

1eq. HCl

1eq. HCl

[Na(H2O)(N5)] 2H2O

[Na(H2O)(N5)] 2H2O

NH2

N N NH NH2

HN N

2

1

H2N

H2N

Page 30 of 30

N N

N N 3 H2O

H2N

HN N N N

N

NH N

NH2

N NH

Cl 2

5

4


N N

N N 3.5 H2O N

Hydrogen Bonding Network: Stabilization of the Pentazolate Anion in

Recommend Documents