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Spin–Spin Artificial DNA Intercalated with Silver Cations: Theoretical Prediction
Author(s) -
Kauch Małgorzata,
Pecul Magdalena
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201100846
Subject(s) - polarizable continuum model , coupling constant , chemistry , density functional theory , stacking , hamiltonian (control theory) , molecular physics , polarizability , molecule , spin (aerodynamics) , ion , computational chemistry , atomic physics , solvation , physics , thermodynamics , quantum mechanics , mathematical optimization , mathematics , organic chemistry
The indirect nuclear spin–spin coupling constants of Ag + cation intercalated between imidazole rings in DNA chains are calculated by means of DFT with relativistic effects taken into account by the use of the zeroth‐order regular approximation Hamiltonian (DFT‐ZORA). The calculations model how the 1 J ( 15 N, 109 Ag) coupling constant is affected by different types of geometry deformations and by the presence of water, which is simulated by means of the polarizable continuum model and explicitly present water molecules. Calculations for systems containing two and three imidazole pairs are also carried out to model the influence of stacking interactions. The computed 1 J ( 15 N, 109 Ag) spin–spin coupling constant is in the range of 85–105 Hz (depending on the computational model) and is in good agreement with the experimental value (ca. 92 Hz). This coupling constant is very little affected by the presence of solvent, stacking interactions, and geometry deformations. Such behavior is explained by visualization of the coupling path by means of coupling energy density (CED). Bigger models allow the coupling constant between two adjacent silver ions to be computed, and give a value of approximately 1 Hz, which is probably too small to be of practical interest. The 2 J ( 15 N, 15 N) value is calculated to be about 2.5 Hz, and is therefore of measurable magnitude.