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K. Prasanna U. Perera Khalil A. Abboud Mariusz Krawiec Don VanDerveer Dennis W. Smith Jr. 《Journal of chemical crystallography》2006,36(6):399-406
A representative compound of bis-ortho-diynyl arene (BODA), with a general formula [(m,p)R2–Ph]2
–X, where R: –C≡C–Ph and X: >C(CF3)2 has been structurally characterized. The compound is being investigated as a monomer for high-performance polyarylene networks and glassy carbon precursors. The bis(trifluoromethyl) derivative crystallizes in two concomitant polymorphic forms. The two polymorphs form a monotropic system with melting points of 436 and 463 K. The metastable form yields monoclinic crystals (P21/n, Z=4). a=12.677(3) ?, b=11.677(2) ?, c=24.026(5) ?, β=93.79(3)°. The thermodynamically stable form is monoclinic as well (P21/c, Z=8), a=10.7983(6) ?, b=30.628(2) ?, c=21.648(1) ?, β=94.737(1)° with small voids indicating less efficient packing. The two polymorphs contain different conformers of the rotationally flexible molecule. 相似文献
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