A series of energetic cyclo-pentazolate salts: rapid synthesis, characterization, and promising performance

Abstract

A family of cyclo-pentazolate anion-based energetic salts was designed and synthesized by a rapid method, and these salts were evaluated as potential next generation energetic materials.

Syntheses of Energetic cyclo‐Pentazolate Salts

“…Compound 1 crystallizes in the monoclinic space group P2 1 /c with four moleculesp er unit cell and ac alculated density of 1.666 gcm À3 at 205 K. Its density is higher than that of NH 3 OH + N 5 À (1.601 gcm À3 at 298 K) and most reported pentazolate salts. [15] Its asymmetric unit is crystallographically independent with one O-(carboxymethyl)hydroxylammonium cation and one cyclo-N 5 À anion ( Figure 1a). Each cyclo-N 5 À anion was stabilized by four hydrogenb onds from four O-(carboxymethyl)hydroxylammonium cations (O3-H3…N3:2 .689 (19) ;N 6-H6A…N1:2 .977(2) ;N 6-H6C…N5: 2.859(2) ;N 6-H6C…N2:2 .949(2) )( Figure 1b).…”

“…Compound 2 has the highest heat of formation of 746.4 kJ mol À1 .T he other two compounds also show positive heats of formation with values of 95.2 (1)t o5 56.1 (3)kJmol À1 ,r espectively.A sc an be seen from Ta ble 1, the heat of formation of 1 is lowest among all selected cyclo-N 5 À -containing compounds. The heats of formation of 2 and 3 are higher than those of GU + N 5 À (203.4 kJ mol À1 ), [12] NH 3 OH + N 5 À (327.6 kJ mol À1 ), [15] NH 4 + N 5 À (269.1 kJ mol À1 ), [15] and AG + N 5 À (392.1 kJ mol À1 ). [15] Based on the calculated densities( 298 K) and solid-state heats of formation,t he detonationp erformances of these salts were calculated using the EXPLO5 program (version6 .01).…”

“…The heats of formation of 2 and 3 are higher than those of GU + N 5 À (203.4 kJ mol À1 ), [12] NH 3 OH + N 5 À (327.6 kJ mol À1 ), [15] NH 4 + N 5 À (269.1 kJ mol À1 ), [15] and AG + N 5 À (392.1 kJ mol À1 ). [15] Based on the calculated densities( 298 K) and solid-state heats of formation,t he detonationp erformances of these salts were calculated using the EXPLO5 program (version6 .01). [23] The salts formed by substituted hydroxylammonium cationsa nd cyclo-N 5 À anion (1, 2)h ave lower detonation performances than NH 3 OH + N 5 À (9005 ms À1 ,3 2.7 GPa).…”

“…[23] The salts formed by substituted hydroxylammonium cationsa nd cyclo-N 5 À anion (1, 2)h ave lower detonation performances than NH 3 OH + N 5 À (9005 ms À1 ,3 2.7 GPa). [15] However,a ll the newly synthesized cyclo-N 5 À salts show higher detonation velocities (> 6896 ms À1 )t han TNT (6881 ms À1 ) and the three-dimensional framework [Na 8 (N 5 ) 8 (H 2 O) 3 ] n (5011ms À1 ). [5] In particular,the energetic performances of compound 1 are superiort ot hose of [Ag(N 5 )] n , [8] GU + N 5 À , [12] DABTT 2 + (N 5 À ) 2 , [12] NH 4 + N 5 À , [15] AG + N 5 À , [15] DAT + N 5 À , [15] and TATT + N 5 À [15] (Table 1).…”

“…[14] Very recently,o ur group synthesized as eries of energetic cyclo-N 5 À salts using metathesis reactions of silver pentazolate and nine chloride salts. [15] The only drawback for this methodi st hat the very poor solubility of the silver pentazolate affects the rate of the metathesis reaction. Therefore, it is very important to find as oluble precursor for the metathesis reactiont of urther optimize this method.…”