THE CRYSTAL AND MOLECULAR-STRUCTURE OF MESOGENIC MALONATES .2.

The crystal and molecular structures of three diethyl-2-{n-[4-(-nitrop henylazo)-phenoxyl]alkyl} malonate with n = 5 (5 PhNO2), 7 (7 PhNO2), 9 (9 PhNO2) and an analogous thyl-2-[4-(4-cyanophenylazo)phenoxy]penty lmalonate (5 PhCN) have been determined with CuKalpha or MoKalpha: 5 P hNO2: a = 8.007(6) Angstrom, b = 11.960(8) Angstrom, c = 13.516(9) Ang strom, alpha = 77.10(6)degrees, beta = 81.80(5)degrees, gamma = 83.15( 5)degrees; R = 0.53; 7 PhNO2: a = 8.074(4) Angstrom, b = 11.592(5) Ang strom, c = 14.422(7) Angstrom, alpha = 87.43(3)degrees, beta = 82.46(3 )degrees, gamma = 85.43(3)degrees; R = 0.072; 9 PhNO2: a = 5.520(5) An gstrom, b = 13.628(9) Angstrom, c = 20.220(11) Angstrom, alpha = 100.0 2(4)degrees, beta = 95.49(4)degrees, gamma = 101.02(4)degrees; R = 0.0 42; 5 PhCN: a = 8.018(6) Angstrom, b = 11.960(9) Angstrom, c = 13.566( 7) Angstrom, alpha = 77.82(5)degrees, beta = 81.89(5)degrees, gamma = 82.69(5)degrees; R = 0.067 (isotropically refined).All these structure s belong to the triclinic space groups P (1) over bar. The arrangement s of the molecules in the crystal of the homologous series of nPhNO(2) suggest two different types of packing independent of n even, odd or large, small. 5 PhCN represents an isomorphous structure to 5 PhNO2. I somophism between 7 PhNO2 and 7 PhCN was confirmed by cocrystallizatio n of these two compounds whose crystal structure was also determined.