9.869(1), b = 17.323(2), c = 16.083(3) A, = 94.85(1)", V = 2739.7(7) A', 2 = 4; 1606 independent reflections with I > 30(I): four-circle diffractometer, Cu,., 3" I 2 6 I 115". Lorentz, polarization, and adsorption corrections and corrections for linear decay were applied to the 3766 independent reflections collected. Anomalous dispersion corrections were applied for Co, K, and Na. The 35 non-hydrogen atoms were located using the SHELXTL Direct Methods programs and the hydrogen atom positions were located. Final cycles of least-squares refinement, which employed anisotropic thermal parameters for non-hydrogen atoms and isotropic parameters for hydrogen atoms, gave R, = 0.053, R, = 0.058. Further details of the crystal structure investigation may be obtained from the Director of the Cambridge Crystallographic Data Centre, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1 EW (England). by quoting the full literature citation.17) The twist angle T and the pyramidalization terms x, and xN were obtained from the primary torsion angles wl, w 2 , and w , as follows: T = (wl + w2)/2; xN = (w2 -0) + n) mod 2~; xc = (w, -IU, + n) mod 2x. Here we use the modified twist angle, ?: Z = (T) modn [3 a]. 7 maximizes at 2 90" and can be interpreted as the angle between the idealized positions ofthe pn orbitals on C and N. The pyramidalization terms maximize at 60". ['ayb'dl It has been found that doping electron-rich discoid polymers with electron acceptors introduces new functional behavior and, moreover, even allows the induction of mesophases in previously non-liquid-crystalline polymers.
Induction of LiquidBecause of charge-transfer (CT) interactions, disc-shaped parts of side-group or main-chain polymers can be arranged in columns, which leads to discotic-columnar mesophases (Fig. 1). Although the functionalization of liquid crystals by doping has been extensively studied,"". b, dl induction of mesophases by mixing of non-liquid-crystalline substances has only been established for a few examples of rod-shaped, low molecular weight Induction of mesophases in amorphous discoid polymers is of special importance since, although numerous amorphous discoid polymers are known,f51 only a few liquid crystalline discotic polymers have been reported. [6* Polyacrylates[81 and polyesters['] containing disc-shaped, electron-rich triphenylene units were employed in these induction experiments. The induction agents were fluorenone derivatives["] with different acceptor strengths: 2,4,7-trinitrofluorenone (TNF) and 2,4,7-trinitrofluoren-9-ylidenemalonodinitrile (TNF-CN). Doping of the polymers was [ liquid crystalline discotic polymer achieved by mixing in solution." The functionalized polymers were characterized by polarization microscopy, differential calorimetry, and X-ray diffraction.["] induction of columnar mesophases in amorphous side-group polymers: The polymethacrylate 1 (T, = 30 "C) and the polyacrylate 2 (T, = -6 "C) were used as amorphous polymers containing electron-rich triphenylene side groups. [5". 81 When com...
