3-Bromothieno[2,3-b]thiophene

    Parameter     ppm  Hz

      D(A)         7.540
      D(B)         7.191
      D(C)         7.615
       J(A,B)         -0.04
       J(A,C)          1.17
       J(B,C)          5.29
     
     BUGGE,A. ET AL. ACTA CHEM.SCAND. 24, 105 (1970)