Molecular recognition of adeninium cations on anionic metal-oxalato frameworks: an experimental and theoretical analysis.
Reactions of adenine with water-soluble oxalato complexes at acidic pH give the compounds (1H,9H-ade)2[Cu(ox)2(H2O)] (1) [H2ade=adeninium cation (1+), ox=oxalato ligand (2-)] and (3H,7H-ade)2[M(ox)2(H2O)2].2H2O [M(II)=Co (2), Zn (3)]. The X-ray single crystal analyses show that the supramolecular architecture of all compounds is built up of anionic sheets of metal-oxalato-water complexes and ribbons of cationic nucleobases among them to afford lamellar inorganic-organic hybrid materials. The molecular recognition process between the organic and the inorganic frameworks determines the isolated tautomeric form of the adeninium cation found in the crystal structures: the canonical 1H,9H for compound 1, and the first solid-state characterized 3H,7H-adeninium tautomer for compounds 2 and 3. Density functional theory calculations have been performed to study the stability of the protonated nucleobase forms and their hydrogen-bonded associations by comparing experimental and theoretical results.
García-Teran
Juan P
JP
Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apartado 644, E-48080 Bilbao, Spain.
Castillo
Oscar
O
Luque
Antonio
A
García-Couceiro
Urko
U
Beobide
Garikoitz
G
Roman
Pascual
P
D000225:Adenine / Q000737:chemistry*; D000838:Anions / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D006860:Hydrogen Bonding; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010071:Oxaloacetates / Q000737:chemistry*
D000838:Anions; D002412:Cations; D008670:Metals; D010071:Oxaloacetates; D000225:Adenine