The reaction of 2,2-dimethylpropane-1,3-diamine (
dmpn) with an excess of concentrated aqueous hydrochloric acid yielded colorless crystals of 2,2-dimethylpropane-1,3-diaminium dichloride,
dmpnH
2Cl
2 (
1), in addition to small amounts of a monohydrate,
dmpnH
2Cl
2∙H
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The reaction of 2,2-dimethylpropane-1,3-diamine (
dmpn) with an excess of concentrated aqueous hydrochloric acid yielded colorless crystals of 2,2-dimethylpropane-1,3-diaminium dichloride,
dmpnH
2Cl
2 (
1), in addition to small amounts of a monohydrate,
dmpnH
2Cl
2∙H
2O (
2). The compounds were studied via X-ray crystallography, IR and Raman spectroscopy, NMR spectroscopy and thermal analysis. Single crystal structure determinations on
1 and
2 showed that
dmpnH
2Cl
2 exists in two polymorphic forms,
1a and
1b. The crystal structure of
1b showed to be much more complex than that of
1a. In the crystal structure of
2, four (
dmpnH
2)
2+ cations and eight chloride anions form a cage constructed by N−H∙∙∙Cl hydrogen bonds. In the center of these cages water dimers with a O∙∙∙O distance of 2.776 (8) Å are present. In addition, a conformational analysis of the 2,2-dimethylpropane-1,3-diaminium cation was performed. The results are compared to the experimental findings of
1a,
1b,
2 and other related hydrogen bonded salt structures from the Cambridge crystallographic structure database (CCDC). Last, a topological classification of the solid-state structures of
1a and
2 was performed and the simplified topological networks are discussed.
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