Single- and double-proton-transfer in the aggregate between cytosine and guaninediazonium ion.
[formula: see text] The structure of "guaninediazonium ion" in its aggregate with cytosine has been explored with ab initio and density functional methods. The hydrogen-bonded aggregate between cytosine and guaninediazonium ion, 1, is a stable minimum, 3. While the isolated enol tautomer of guaninediazonium ion, 2, is significantly more stable than 1, the tautomeric aggregate 4 that results from double-proton-transfer in 3 is almost isoenergetic with 3. Most interesting and entirely unexpected is the finding that neither 3 nor 4 is predicted to be the thermodynamically predominant structure. Instead, single-proton-transfer to cytosine results in the most stable cytosinium-guaninediazo complex, 5.
Glaser
R
R
Department of Chemistry, University of Missouri-Columbia 65211, USA. glaserr@missouri.edu
Lewis
M
M
D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D003979:Diazonium Compounds / Q000737:chemistry*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D011522:Protons; D013816:Thermodynamics
D003979:Diazonium Compounds; D011522:Protons; C410450:guaninediazonium; D006147:Guanine; D003596:Cytosine; D004247:DNA