The Photoexcited Triplet State of the Azulenium Cation¹

Self-association of Verapamil in Aqueous Electrolyte Solution

“…Upfield shifts on increase of concentra- tion were larger in the case of the aromatic protons (Table 2) indicative of an intermolecular ring current effect as the two phenyl ring systems associate to form the micelle core (12,13). Similar upfield shifts of the aromatic protons have been noted, for example, for the micellization of ω-phenylalkyltrimethylammonium bromides (14, 15) and sodium ω-phenyl decanoate (16) and are also characteristic of compounds that exhibit a stacking mode of association such as nucleotides (17), dyes (18,19), phenothiazine drugs (20), and penicillins (21,22). Protons 2 and 4 corresponding to methyl groups adjacent to the phenyl ring undergo smaller upfield shifts, while proton 3 situated on the alkyl chain shows a small downfield shift.…”