Nitro derivatives of N-alkylbenzoaza-15-crown-5: synthesis, structures, and complexation with metal and ammonium cations

作者：Dmitrieva S N; Churakova M V; Kurchavov N A; Vedernikov A I; Kuz'mina L G; Freidzon A Ya; Bagatur'yants A A; Strelenko Yu A; Howard J A K; Gromov S P^*

来源：Russian Chemical Bulletin, 2010, 59(6): 1192-1206.

DOI：10.1007/s11172-010-0222-0

• benzoazacrown ethers
• synthesis
• structures
• complexation
• metal cations
• ammonium ions
• stability constants
• X-ray diffraction analysis
• (1)H NMR spectroscopy
• quantum chemical calculations
• density functional theory

A number of N-alkylnitrobenzoaza-15-crown-5 with the macrocycle N atom conjugated with the benzene ring were obtained. The structural and complexing properties of these compounds were compared with those of model nitrobenzo- and N-(4-nitrophenyl)aza-15-crown-5 using X-ray diffraction, (1)H NMR spectroscopy, and DFT calculations. The macrocyclic N atom of benzoazacrown ethers are characterized by a considerable contribution of the sp3-hybridized state and a pronounced pyramidal geometry; the crownlike conformation of the macrocycle is preorganized for cation binding, which facilitates complexation. The stability constants of the complexes of crown ethers with the NH(4) (+), EtNH(3) (+), Na(+), K(+), Ca(2+), and Ba(2+) ions were determined by 1H NMR titration in MeCN-d(3). The most stable complexes were obtained with alkaline-earth metal cations, which is due to the higher charge density at these cations. The characteristics of the complexing ability of N-alkylnitrobenzoaza-15-crown-5 toward alkaline earth metal cations are comparable with analogous characteristics of nitrobenzo-15-crown-5 and are much better than those of N-(4-nitrophenyl)aza-15-crown-5.

• 出版日期2010-6