Nucleobases, aromaticity adenine

Very few reports of the excited-state structural dynamics of the purine nucleobases have appeared in the literature. This lack of research effort is probably due to a number of factors. The primary factor is the lack of photochemistry seen in the purines. Although adenine can form photoadducts with thymine, and this accounts for 0.2% of the photolesions found upon UVC irradiation of DNA [67], the purines appear to be relatively robust to UV irradiation. This lack of photoreactivity is probably due to the aromatic nature of the purine nucleobases. A practical issue with the purine nucleobases is their insolubility in water. While adenine enjoys reasonable solubility, it is almost an order of magnitude lower than that of thymine and uracil, the two most soluble nucleobases [143], Guanine is almost completely insoluble in water at room temperature [143],... 

Here, the spacer may not be a simple building element but an appropriate aromatic moiety. In that case, the host enjoys simultaneously the possibility of Watson-Crick and Hoogsteen H-bonding and of aromatic stacking with the complexed nucleobase. For example, the 2,7-naphthalene compounds depicted below (X = NH, O) were shown to transport adenine... 

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