Investigation of β-cyclodextrin complex formation with 2,2′-dipyridine in ground and excited triplet states

Abstract

It was found that 2,2′-dipyridine ( $$DP$$ ) forms inclusion complex with beta-cyclodextrin ( $$CD$$ ) in basic water solution by using NMR and spectrophotometry. Complex formation does not have an effect on the yield of triplet excited 2,2′-dipyridine. Triplet excited 2,2′-dipyridine $$({}^{3}DP)$$ also forms inclusion complex with beta-cyclodextrin and the value of complex formation constant is close to that for $$DP$$ in the ground state. The electron transfer rate constant between the inclusion complex of $${}^{3}DP$$ with $$CD$$ and N-acetyl-l-tyrosine ( $$TyrOH$$ ) is about ten times less than between $${}^{3}DP$$ in free (non complexed) state and $$TyrOH$$ in basic (pH 11) solution. Also it was found that inclusion complex formation of $${}^{3}DP$$ with $$CD$$ slightly decreases the rate constant of triplet–triplet annihilation process.