title: Diethyl 2,3-dihydro-thieno[3,4-b]-1,4-dioxine-5,7-dicarboxyl-ate.
abstract: The title compound, C(12)H(14)O(6)S, is a dicarboxylic acid diethyl ester of 3,4-ethyl-enedioxy-thio-phene, which is a component of electrically conductive poly(3,4-ethyl-enedioxy-thio-phene) (PEDOT). The ethyl-ene group is disordered over two sites with occupancy factors 0.64 and 0.36. Both the carbonyl groups are coplanar with the thio-phene ring. The mol-ecules form centrosymmetric dimers with an R(2) (2)(12) coupling by inter-molecular C-H⋯O hydrogen bonds [3.333 (5) Å] at the ethoxy-carbonyl groups. The dimer units are arranged to form a ribbon-like mol-ecular sheet.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ono
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tomura
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Saito