Onset of chiral adenine surface growth.
The structure and stability of adenine crystals and thin layers has been studied by using scanning tunneling microscopy, X-ray diffraction, and density functional theory calculations. We have found that adenine crystals can be grown in two phases that are energetically quasi-degenerate, the structure of which can be described as a pile-up of 2D adenine planes. In each plane, the structure can be described as an aggregation of adenine dimers. Under certain conditions, kinetic effects can favor the growth of the less stable phase. These results have been used to understand the growth of adenine thin films on gold under ultra-high vacuum conditions. We have found that the grown phase corresponds to the α-phase, which is composed of stacked prochiral planes. In this way, the adenine nanocrystals exhibit a surface that is enantiopure. These results could open new insight into the applications of adenine in biological, medical, and enantioselective or pharmaceutical fields.
Instituto de Estructura de la Materia-CSIC c/Serrano 119, 28006 Madrid (Spain).
María Jose
MJ
Capitán
Jesús
J
Álvarez
Yang
Y
Wang
Roberto
R
Otero
Manuel
M
Alcamí
Fernando
F
Martín
Rodolfo
R
Miranda
D000225:Adenine / Q000737:chemistry*; D018360:Crystallography, X-Ray; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D008968:Molecular Conformation; D011208:Powders; D013499:Surface Properties; D014961:X-Ray Diffraction
D011208:Powders; D000225:Adenine
adenine; chirality; crystal growth; nucleobases; surface growth