Supramolecular structures of three configurational isomers of 1-phenylethanaminium malate(1-).

In rac-1-phenylethanaminium rac-malate(1ÿ), C8H12N C4H5O5 ÿ, (I), the anions are linked by two inter-anion OÐ H O hydrogen bonds into sheets generated by a glide plane and hence containing both enantiomers of the anion. The cations are linked to the anion sheets by three NÐH O hydrogen bonds, such that cations of R con®guration are bonded to one face of the sheet and cations of S con®guration are bonded to the other face. In (R)-1-phenylethanaminium (S)-malate(1ÿ), C8H12N C4H5O5, (III), the anions are again linked by two OÐH O hydrogen bonds, in one of which the H atom is disordered over two sites, into sheets very similar to those in (I) but which are generated in (III) by translation and so contain only a single enantiomer. The cations in (III) are linked to the anion sheets by three NÐH O hydrogen bonds, but the cations are bonded to only one face of the anion sheet. Co-crystallization of (R)-1-phenylethanamine with rac-malic acid gives the salt (R)-1-phenylethanaminium malate(1ÿ) C8H12N C4H5O5, (II), with a structure very similar to that of (III) but where only ca 75% of the anion sites are occupied by (S)-malate(1ÿ), with the remaining 25% occupied by (R)-malate(1ÿ). The layers in (II) show a signi®cant displacement along the [001] direction compared with those in (III).