Stoichiometric and polymorphic salts of hexa­methyl­ene­tetra­minium and 2-chloro-4-nitro­benzoate

Acta Crystallographica Section E: Crystallographic Communications

Lemmerer, A.¹  Motlaung, X.¹ 

[1] Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag, PO WITS, 2050, Johannesburg, South Africa

关键词: CRYSTAL STRUCTURE;    MOLECULAR SALTS;    STOICHIOMETRIC RATIO;    POLYMORPHS;   

DOI  :  10.1107/S2056989017014359

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

Four mol­ecular salts made from hexa­methyl­ene­tetra­minium and 2-chloro-4-nitro­benzoate have been synthesized and are reported, namely ammonium hexa­methyl­ene­tetra­minium bis­(2-chloro-4-nitro­benzoate), NH4+·C6H13N4+·2C7H3ClNO4−, (I), hexa­methyl­ene­tetra­minium hydrogen bis­(2-chloro-4-nitro­benzoate), 0.5C6H13N4+·C7H3.50ClNO4−, (II), hexa­methyl­ene­tetra­minium 2-chloro-4-nitro­benzoate, C6H13N4+·C7H3ClNO4−, (IIIa) and (IIIb). All four mol­ecular salts show N+—H⋯O− hydrogen bonding. Salt (I) crystallized out with an NH4+ counter-ion which came from decomposition of 50% of the hexa­methyl­ene­tetra­minium cation in solution. (II) shows an unusual asymmetric unit, with both a hexa­methyl­ene­tetra­minium cation and a partially deproton­ated 2-chloro-4-nitro­benzoate anion. Salts (IIIa) and (IIIb) are polymorphs of each other. This work shows that hexamethylenetetramine only protonates once, even in the presence of excess acid.

【 授权许可】

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