1H-NMR studies on the ternary complexes of rare-earth ions with thenoyltrifluoroacetone and polyethers in dichloromethane.
The structures of the ternary complexes of lanthanoid and yttrium (Ln3+)-thenoyltrifluoroacetonates (tta-) with polyether (POE) in organic phase were investigated by 1H-NMR spectroscopy, where the POEs are crown ethers (18-crown-6 and benzo-18-crown-6) and monodispersed linear polyethers (DEOn: HO-(CH2CH2O-)nC12H25, where n=4, 6, 8). The changes in chemical shift of methylene protons of POE by addition of the adduct complex [Ln(tta)3(POE)] were measured at various Ln3+-to-POE concentration ratios. Chemical shift changes for each proton of POE by the formation of [Ln(tta)3(POE)] were determined. Results revealed that oxygen atoms at the hydroxyl terminal of linear POE have higher tendency to coordinate to the metal ion in [Ln(tta)3] complex. Three (for La3+) or two (for Lu3+ or Y3+) oxygen atoms of the POE coordinate to the metal ion without substitution of tta- ligands to satisfy the metal ion's coordination number of nine or eight, respectively. In the case of 18-membered crown ether complexes, La3+ is incorporated inside the cavity of the POE, displacing one of the three tta- from the inner coordination sphere while the other two remain coordinated to the metal ion. On the other hand, for the adduct of Y3+ complex with crown ether, all three tta- ligands are directly coordinating to the metal ion.
Gagabe
Gene Frederick
GF
Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan.
Satoh
Keiichi
K
Sawada
Kiyoshi
K
D002412:Cations; D004987:Ethers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008674:Metals, Rare Earth / Q000737:chemistry*; D008752:Methylene Chloride / Q000737:chemistry*; D011522:Protons; D013804:Thenoyltrifluoroacetone / Q000737:chemistry*
D002412:Cations; D004987:Ethers; D008674:Metals, Rare Earth; D011522:Protons; D013804:Thenoyltrifluoroacetone; D008752:Methylene Chloride