| abstract |
Flow batteries and other electrochemical systems can contain an active material that is a coordination complex having at least one monosulfonated catecholate ligand or a salt thereof bound to a metal center. The monosulfonated catecholate ligand has a structure of n nMore particularly, the coordination complex can be a titanium coordination complex with a formula of D g Ti(L 1 )(L 2 )(L 3 ), in which D is a counterion selected from H, NH 4 + , Li + , Na + , K + , or any combination thereof g ranges between 3 and 6; and L 1 , L 2 and L 3 are ligands, where at least one of L 1 , L 2 and L 3 is a monosulfonated catecholate ligand. Methods for synthesizing such monosulfonated catecholate ligands can include providing a neat mixture of catechol and up to about 1.3 stoichiometric equivalents of sulfuric acid, and heating the neat mixture at a temperature of about 80° C. or above to form 3,4-dihydroxybenzenesulfonic acid or a salt thereof. |