Xanthene-Based Ligand with Two Adjacent β-Diiminato Binding Sites

A novel potential ligand has been designed where two β-dialdimine units are linked by a xanthene backbone
(H2Xanthdim). The synthesis proceeds via a double vinamidinium salt and the products of its hydrolysis
(containing eneamine/malonaldehyde units), which were converted into H2Xanthdim via a reaction with
2,3-dimethylaniline. The reaction of H2Xanthdim with n-butyllithium yields ((Et2O)Li)2Xanthdim, which
was isolated and crystallized. The crystal structures of both H2Xanthdim and its lithium salt are discussed.