CRYSTAL STRUCTURE OF LONG CHAIN COMPOUND, 1,13-TRIDECANEDIOL. N. Nakamura, Y. Tanihara and T. Takayama, Department of Chemistry, Ritsumeikan University, Kusatsu, Shiga 525-77, Japan.

Crystal structures of normal long chain compounds are quite similar to that of liquid crystals. For example, normal paraffins show smectic A or smectic C like structure. And some of them exhibit high temperature phase in which molecules rotate around its long axes. The crystal structure of 1,13-tridecanediol was analyzed as one of the model compounds of liquid crystals. A selected thin plate crystal having approximate dimensions of 0.50 x 0.30 x 0.10 mm was used. The intensity data from a single crystal were collected by RIGAKU AFC5R diffractometer with graphite monochromated CuK( radiation. The data were collected at a room temperature of 296+/-1K using (-2( scan technique to a maximum 2( value of 120.0deg.. The intensities of three representative reflections were measured after every 150 reflections. An empirical absorption correction based on azimuthal scans of several reflections was applied. The data were corrected for Lorentz and polarization effects. The structure was solved by direct methods with SIR88 and expanded using Fourier with DIRDIF92. The final cycle of full-matrix least-squares refinement was based on observed reflections [I>5.0((I)] and 137 variable parameters, (w(|Fo|-|Fc|)₂ minimized, R=0.079, wR=0.108. Crystal data obtained are as follows, C₁₃H₂₈O₂=216.36, a=7.143(2), b=37.541(7), c=5.111(1)Å, (=90.00, (=90.00, (=90.00, P2₁2₁2₁, Z=4. One of the most interesting feature of this molecule is that one of the two terminal hydroxyl groups shows gauche conformation, whereas the another one shows trans conformation.