Fluoroaluminates of purine and DNA bases, adenine, guanine: [Hpur](2)center dot(AlF5), [Hade](3)center dot(AlF6)center dot 6.5H(2)O, [Hguan](3)center dot(Al3F12)

New purinium, adeninium and guaninium fluoroaluminates, [Hpur](2)center dot(AlF5), [Hade](3)center dot(AlF6)center dot 6.5H(2)O and [Hguan](3)center dot(Al3F12), are synthesized by microwave heating assisted hydrothermal synthesis at 120 degrees C or 190 degrees C. The crystallisation is difficult; all crystals of [Hpur](2)center dot(AlF6) and [Hade](3)center dot(AlF6)center dot 6.5H(2)O are very small while only a microcrystalline powder of [Hguan](3)center dot(Al3F12) is obtained. The structures are determined from crystal ([Hpur](2)center dot(AlF5) and [Hade](3)center dot(AlF6)center dot 6.5H(2)O) or powder ([Hguan](3)center dot Al3F12)) X-ray diffraction data. In [Hpur](2)center dot(AlF5), trans-chains of corner sharing octahedra lie along the c axis of the tetragonal cell (a = 18.997 (2) angstrom, c = 3.6980(4) angstrom, P4/n, Z = 4). In [Hade](3)center dot(AlF6)center dot 6.5H(2)O, the octahedral AlF6 units lie in (010) planes with water molecules. In [Hguan](3) (Al3F12), trimers of corner sharing octahedra are associated by opposite vertices along the c axis of the trigonal cell (a = 14.254(1) angstrom. c = 3.629(1) angstrom, P3, Z = 1). The purine, adenine and guanine amines are monoprotonated and lie between the preceding chains or layers. Hydrogen bonds between fluoride ions and amine groups of organic cations or, eventually, water molecules ensure the stability of the structures, together with N-H center dot center dot center dot O intermolecular bonds between guaninium cations in [Hguan](3)center dot(Al3F12). The N(7)H-amino and N(9)H-amino tautomeric forms of [Hade](+) are simultaneously found in [Hade](3)center dot(AlF6)center dot 6.5H(2)O. (C) 2010 Elsevier Masson SAS. All rights reserved.