Sensing Ethylene with Silver(I)-bound Fluoroionophores and Development and Assessment of "Fun with Chemistry" Camps

Abstract

Four anthracene-based ligands were synthesized bearing thiaazaalkanes at the 9 position, which were linked through either a methylene or a carbonyl bridge. Titrations of these ligands with AgSbF6 in 70:30 CH 2 Cl2 :EtOH solution showed that Ag(I) binding affinities decreased as the number of Lewis base donor atoms decreased. Specifically, the Ag(I) affinities were: 6-(9'-anthrylmethyl)-3,9-dithia-6-azaundecane (NS 2 Anthramine ), 1 × 107 M -1 > 6-(9'-anthrylmethyl)-3-thia-6-azaoctane (NSAnthramine ), 1 × 105 M-1 > 6-(9'-anthracenecarbonyl)-3,9-dithia-6-azaundecane (NS2 Anthramide ), 1 × 103 M -1 > 6-(9'-anthracenecarbonyl)-3-thia-6-azaoctane (NSAnthramide ), ∼1 × 101 M-1 . Ligands with amine-based ionophores, NS2 Anthramine and NSAnthramine , exhibited changes in the absorbance and emission spectra related to binding between Ag(I) and the N lone pair. These changes included a 7-nm bathochromic shift for all absorbance bands upon addition of 1 equiv Ag(I), and an increase in emission intensity due to the relief of photoinduced electron transfer from the amine to the anthracene. Ag(I)-bound