Synthesis and coordination chemistry of unsymmetrical tetraazaporphyrins containing single oxathia- and thiacrown substituents

Singly crowned porphyrazines containing oxathia- and thiacrown ethers were prepared from a mixed condensation of 1,2-dicyanobenzene or its 3,4-dibutyl analog and the appropriate crowned maleonitrile precursor. Peripheral metal-binding to each porphyrazine was examined spectrophotometrically. The oxathiaether-crowned porphyrazines were found to coordinate Ag(I) and HgCl₂, though all complexes suffered from poor solubility and complexes with the latter were unstable in polar media. With an interest in the formation of comparatively more stable and soluble heavy and transition metal complexes, two new sets of thiaether-crowned porphyrazines were examined. In these cases, coordination of Hg(II), Ag(I), Cu(I) and Cu(II) was observed with no evidence for complexation of Tl(I), Pb(II) or CdCl₂. (C) 2000 Elsevier Science Ltd.