The molecule is a HEPES that is ethanesulfonate substituted by a 4-(2-hydroxyethyl)piperazin-4-ium-1-yl group at position 2. It is a conjugate acid of a 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonate. It is a tautomer of a 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid.
2-[4-(2-hydroxyethyl)piperazin-4-ium-1-yl]ethanesulfonate