title: Solid state forms of 4-aminoquinaldine - From void structures with and without solvent inclusion to close packing.
abstract: Polymorphs of 4-aminoquinaldine (4-AQ) have been predicted in silico and experimentally identified and characterised. The two metastable forms,AH(anhydrate)IIandAH III, crystallise in the trigonal space group [Formula: see text] and are less densely packed than the thermodynamically most stable phaseAH I°(P21/c).AH IIcan crystallise and exist both, as a solvent inclusion compound and as an unsolvated phase. The third polymorph,AH III, is exclusively obtained by desolvation of a carbon tetrachloride solvate. Theoretical calculations correctly estimated the experimental 0K stability order, confirmed thatAH IIcan exist without solvents, gave access to theAH IIIstructure, and identified that there exists a subtle balance between close packing and number of hydrogen bonding interactions in the solid state of anhydrous4-AQ. Furthermore, the prevalence of void space and solvent inclusion in [Formula: see text] structures is discussed.
authors.affiliation: Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
authors.forename: Doris E
authors.initials: DE
authors.lastname: Braun
authors.affiliation: Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gelbrich
authors.affiliation: Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria.
authors.forename: Volker
authors.initials: V
authors.lastname: Kahlenberg
authors.affiliation: Institute of Pharmacy, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Griesser