Structure of tetramethyl reductic acid (TMRA, 4,4,5,5-tetramethyl-2,3-dihydroxy-2-cyclopenten-1-one), a reductate ligand involved in dioxygen activation by multinuclear iron complexes.

C9H14O3, Mr = 170.21, orthorhombic, Pbca, a = 11.651 (2), b = 12.279 (2), c = 26.257 (4) A, V = 3756 A3, Z = 16, Dx = 1.204, Dm = 1.19 (1) g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 7.01 cm-1, F(000) = 1472, T = 297 (1) K, R = 0.051 for 2152 observed reflections with F greater than 6 sigma(F). The title compound adopts a well-defined conjugated structure corresponding to one of its expected resonance forms. There are two independent molecules in the asymmetric unit owing to two different intermolecular hydrogen-bonding modes.