Unusual hydrate stabilization in the two-dimensional layered structure of quinacrinium bis(2-carboxy-4,5-dichlorobenzoate) tetrahydrate, a proton-transfer compound of the drug quinacrine.
The crystal structure of the hydrated proton-transfer compound of the drug quinacrine [rac-N'-(6-chloro-2-methoxyacridin-9-yl)-N,N-diethylpentane-1,4-diamine] with 4,5-dichlorophthalic acid, C(23)H(32)ClN(3)O(2+).2C(8)H(3)Cl(2)O(4)(-).4H(2)O, has been determined at 200 K. The four labile water molecules of solvation in the structure form discrete ...O-H...O-H... hydrogen-bonded chains parallel to the quinacrine side chain, the two N-H groups of which act as hydrogen-bond donors for two of the water acceptor molecules. The other water molecules, as well as the acridinium H atom, also form hydrogen bonds with the two anion species and extend the structure into two-dimensional sheets. Between these sheets there are also weak cation-anion and anion-anion pi-pi aromatic ring interactions. This structure represents the third example of a simple quinacrine derivative for which structural data are available but differs from the other two in that it is unstable in the X-ray beam due to efflorescence, probably associated with the destruction of the unusual four-membered water chain structures.
Smith
Graham
G
School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Australia. g.smith@qut.edu.au
Wermuth
Urs D
UD
Sagatys
Dalius S
DS
D000962:Antimalarials / Q000737:chemistry*; D002723:Chlorobenzoates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D015394:Molecular Structure; D011522:Protons; D011796:Quinacrine / Q000737:chemistry*
C532207:2-carboxyanilinium 2-carboxy-4,5-dichlorobenzoate dihydrate; D000962:Antimalarials; D002723:Chlorobenzoates; D011522:Protons; D011796:Quinacrine