Radicals formed in cytosine-hydrochloride(thiocytosine) single crystals: Insights from a DFT study

Specific properties of chlorine interaction with thiocytosine in comparison to chlorine interaction with cytosine in the system formed by the incorporation of small amount of thiocytosine in a cytosine-hydrochloride crystal lattice have been investigated by DFT calculations of the g-tensor of sulfur centered radical. Taking account of the crystal environment of the radical site it has been shown that the main reason for difficulties in interpretation of spectroscopic as well as theoretical results in this model system is the considerable spin density spread on both chlorine and sulfur atoms. From comparison of the results for the proposed model structure with accessible spectroscopic data, the specific direction in which charge transfer in the investigated system may take place has been pointed out.