| Abstrakt: |
In the structure of the title salt, [Li2(C6N8O8)(H2O)4]n, the 3,30,5,50 -tetranitro-4,4-bipyrazole-1,10-diide dianion [{TNBPz}2-] is situated across the twofold axis. The distorted coordination octahedra around Li+ involve four short bonds with two pyrazolate N atoms and two aqua ligands [Li--N(O) = 1.999 (3)2.090 (2) Â] and two longer contacts with nitro-O atoms [2.550 (2), 2.636 (2) Â]. When combined with μ4-{TNBPz}2_, this generates a mono-periodic polymeric structure incorporating discrete centrosymmeric [(H2O)2Li-(dinitropyrazolato) 2-Li(H2O)2] units. The three-dimensional stack of mutually orthogonal coordination chains is reminiscent of a Lincoln log pattern. It is influenced by conventional hydrogen bonding [O--O = 2.8555 (17)3.0010 (15) Â] and multiple lone pair-:n hole interactions of the nitro groups [N--O = 3.0349 (15) and 3.0887 (15) Â]. The Hirshfeld surface and twodimensional fingerprint plots also support the significance of non-covalent bonding. Coordinative saturation and a favorable geometry at the Li+ ions, dense packing of the polymeric subconnectivities and particularly extensive interanion interactions may be involved in the stabilization of the structure. The title salt is a rare example of an energetic Li nitroazolate, which nicely crystallizes from aqueous solution and is neither hygroscopic nor efflorescent. The TG/DTÂ data reveal total dehydration in the range of 330-430 K and stability of the anhydrous material up to 633-653 K. [ABSTRACT FROM AUTHOR] |
