Experimental and theoretical studies on the coordination chemistry of the N1-hexyl substituted pyrimidines (uracil, 5-fluorouracil and cytosine)

Abstract

N ¹-Hexyl substituted pyrimidines were shown to present solubility properties closer to the real bases than the commonly used methyl and ethyl derivatives, yielding bi-layered structures in the solid state. The study of their coordination capabilities, mainly with Ag(I) and Hg(II), is presented in order to prove their reactivity. A series of coordination complexes, namely, [Hg(N¹-hexyl-5-fluorouracilate)₂]₄·6H₂O (1), (Ag⁺)·[Ag(N¹-hexyl-5-fluorouracilate)₂]⁻ (2), [Ag(NO₃)(N¹-hexyluracil-κO⁴)₄] (3), [ZnBr₂(N¹-hexylcytosine)₂] (4), [CdBr₂(N¹-hexylcytosine)₂] (5), [HgBr₂(N¹-hexylcytosine)₂] (6) and [CoBr₂(N¹-hexylcytosine)₂] (7), have been synthesized in good yields and X-ray characterized. The presence of the hexyl chains and the fluorine atoms causes the formation of interesting 3D architectures in the solid state. Their structures have been further characterized by infrared spectra (IR) and elemental analyses. In addition, DFT-D3 calculations are used to study interesting noncovalent interactions observed in the solid state, like fluorine–fluorine, fluorine–π and hydrophobic interactions.