Chiral -Symmetric Diimines with 4,5-Diazafluorene Units.

A synthetic approach to a new group of stable chiral -symmetric diimines with the 4,5-diazafluorene core has been developed based on condensation of dipinodiazafluorene with aromatic diamines. The chemical structures of new compounds were proven by spectroscopic methods and X-ray crystallography. All the compounds form solvates with organic solvents (chloroform, benzene, 1,4-dioxane) and water.

Bis(DL-cysteinium) oxalate.

In the title compound, 2C3H8NO2S+.C2O4(2-), the oxalate anion occupies an inversion centre and is coordinated to cysteine molecules of different chirality (L and D) via O-H..