N,N'-Bis(ortho-Acylaryl)Diaza-18-Crown-6 Ethers: Synthesis, Complexation in Solution, and Crystal Structure of the Complex with Lead Perchlorate

摘要

Two new lariat ethers were obtained from N,N'-diaryldiaza-18-crown-6 (Ar = 2-formyl-4-meth-ylphenyl (II) and 2-benzoyl-4-methylphenyl (III)). In the ethers obtained, the carbonyl O atoms act as additional electron-donating sites. Complexation of lariat ethers II and III with metal cations in solution was studied by ~1H NMR spectroscopy (acetone-d6, methanol-d4). The stability constants of the resulting complexes were determined. For lariat ether III and its complexes, the magnetic anisotropy of the benzoyl groups substantially influences the chemical shifts of the protons of the macrocycle. The stability of the complexes increases from ether II to III and in the order K~+ < Ba~(2+) < Pb~(2+). Complexes with La~(3+) were not obtained. The complex of lariat ether II (L) with Pb(ClO4)2, [PbL(H2O)](ClO4)2·H2O, was characterized by X-ray diffraction. The Pb~(2+) cation is in the cavity of the lariat ether and is coordinated by the formyl O atoms on one side of the macrocycle plane and by the water molecule on the other side (C.N. 9).