No abstract

The crystallization of 1, l'-binaphthyl from its racemic melt is an example of spontaneous generation of optical activity. The distribution of specific rotations in 200 individual samples varied from [alpha](D) = -218 degrees to [alpha](D) = +206 degrees with a mean of +0.14 degree and standard deviation of 86.4 degrees. This resolution into enantiomers is determined by chance development, with equal probability, of right- or left-handed crystallites; it can be controlled and made stereospecific by addition of dissymmetric compounds at low concentrations.

No abstract

In these complexes the p-quinones are undoubtedly coordinated through their olefinic portions1 since vc-o suffers only a slight decrease of about 30 cm-1. Their nmr spectra are also consistent with this mode of bonding.

The thermal racemization of polycrystalline samples of neat (+)-bicyclo[2.2.1]hept-5-ene-íran¿-2,3dicarboxylic acid (mp 176°) has been studied from 130 to 194°. Up to 165°the reaction occurs in the solid state (AH* = 40.0 kcal/mol, AS -= 14 eu) at a rate only ca. one-tenth of the melt rate extrapolated to these temperatures (for the melt at 176-194°, AH* = 29.7 kcal/mol, 5* = -6.9 eu). The strictly first-order solid-state reaction has no inhibition period and is unaffected by crystal size or optical purity of samples. This reverse Diels-Alder reaction and recombination occur throughout the bulk of polycrystalline sample rather than at crystal defects or impurity sites. X-Ray diffraction patterns of partially racemized samples taken from runs below the eutectic temperature of 165°show growth of (±)-racemic compound (mp 186°).