Crystal Structures of 5,6,5 ',6 '-Tetramethoxy-1,1 '-spirobisindane-3,3 '-dione and two of its Fluorene Adducts

The structures of three spirobisindanes 1, 2a and 2b are reported. Each compound is a precursor to a Polymers of Intrinsic Microporosity (PIM) and is the component that provides the necessary site of contortion within the polymer. Of particular importance are the angles formed between the aromatic units around the spiro-centre as it may have direct relevance to the inefficiency of packing in the solid state packing, we think, induces microporosity in the final polymer. Compound 1 crystallized in the monoclinic P21/c space group with unit cell parameters a = 9.8000(5) angstrom, b = 17.8710(9) angstrom, c = 10.4100(5) angstrom, beta = 106.6280(10)degrees, V = 1746.92(15) A(3), Z = 4, D = 1.401 Mg/m(3). Compound 2a crystallized in the monoclinic P21/c space group with unit cell parameters a = 9.7460(13) angstrom, b = 30.291(4) angstrom, c = 8.6740(12) angstrom ', beta = 97.111(3)degrees, 2541.0(6) A(3), Z = 4, D = 1.319 Mg/m(3). Compound 2b crystallized in the monoclinic P21/n space group with unit cell parameters a = 13.5670(9) angstrom, b = 12.7930(8) angstrom, c = 22.1960(14) angstrom, beta = 96.6630(10)degrees, V = 3826.4(4) A(3), Z = 4, D = 1.265 Mg/m(3).