Dioxygen affinities and catalytic oxidation performance of unsymmetrical bis-Schiff base transition-metal complexes with aza-crown pendant groups was written by Wei, Xing-yue;Qin, Sheng-ying. And the article was included in Journal of Chemical Research in 2008.Product Details of 66943-05-3 This article mentions the following:
CoII and MnIII complexes with aza-crown substituted, unsym. bis-Schiff base ligands were synthesized starting from monoaza-15-crown-5 or benzo-10-aza-15-crown-5. The saturated oxygen uptake of the CoII complexes [CoL1]-[CoL4] in diethyleneglycol/dimethyl ether solution were determined at different temperatures The oxygenation constant (Ko2) and thermodn. parameters (ΔH°, ΔS°) were calculated The MnIII complexes ([MnL1Cl]-[MnL4Cl]) were employed to catalyze styrene oxidation using mol. oxygen at ambient temperature and pressure. The modulation of O2-binding capabilities and catalytic oxidation performance by the aza-crown ether pendant groups in [ML3] and [ML4] were studied as compared with the parent complexes [ML1] and morpholino-substituted analog [ML2]. The dioxygen affinities and catalytic oxidation activities of [CoL3] and [CoL4] were much more enhanced by aza-crown pendants. Moreover, the O2-binding capabilities of [CoL3] and [CoL4] were also improved by adding alkali metal cations (Li+, Na+ and K+) to the system, and adding Na+ shows the most significant enhancement of dioxygen affinities. Likewise, [MnL3Cl] and [MnL4Cl] exhibit the best catalytic activities: the conversion of styrene to benzaldehyde are up to 41.2% and 45.8% with >99% selectivity. In the experiment, the researchers used many compounds, for example, 1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3Product Details of 66943-05-3).
1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3) belongs to ethers. Of all the functional groups, ethers are the least reactive ones. Ether bonds are quite stable towards bases, oxidizing agents and reducing agents. But on the other hand, ethers undergo cleavage by reaction with acids. The unique properties of ethers (i.e., that they are strongly polar, with nonbonding electron pairs but no hydroxyl group) enhance the formation and use of many reagents. For example, Grignard reagents cannot form unless an ether is present to share its lone pair of electrons with the magnesium atom. Complexation of the magnesium atom stabilizes the Grignard reagent and helps to keep it in solution.Product Details of 66943-05-3
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem