Controllable synthesis of nucleotide complex based on pH control: A small-molecule fluorescent probe as an auxiliary ligand to indicate the pre-organization of the nucleotide complex in solution

Different CMP-bpe-M(ii) (CMP = cytidine monophosphate, bpe = bis(4-pyridyl)ethylene, M(ii) = Mn²⁺ and Co²⁺) complexes are synthesized controllably based on pH control and well studied by X-ray single-crystal diffraction analysis. Interestingly, the suitable pH conditions are explored by considering the pre-organization modes of CMP, bpe, and M²⁺ in aqueous solution by fluorescence spectroscopy based on acid/basic titration. The organic base bpe serves as a small-molecule fluorescent probe to indicate the changes of pre-organization modes along with the changes of the solution acidity. Furthermore, a perfect self-complementary sugar-base hydrogen bond is first reported based on the crystal structure analysis in this work, and different chiralities and SHG activities of CMP-bpe-Mn(ii) complexes obtained at different pH values are studied.