H-1 NMR spectra of some amines coordinated to the paramagnetic polyoxometalate, [(SiW11CoO39)-O-II](6-)

H-1 NMR spectra of methyl-, ethyl-, propyl-, isopropyl-, butyl-, N-methylet hyl-, N-methylpropyl-, and N-methylisopropylamine coordinated to the parama gnetic 11-tungstocobalto(LI)silicate anion (SiW11Co) in dimethylsulfoxide-d (6) or dimethylformamide-d(7) are reported. For these complexes the ligand exchange is slow on the NMR time scale and pure H-1 NMR signals have been o bserved at room temperature. No complex is detected in D2O. From the pseudo contact shifts of the CH2 and CH3 groups in ethylamine the energy of the ga uche conformers with respect to the anti conformer is estimated. Two diaste reotopic protons in the CH2 group of N-methylethylamine have quite differen t chemical shifts especially at low temperatures (e.g. 48.5 vs. 19.4 ppm at -10 degrees C). This may be attributed mainly to the different positions o f the two protons in the most stable (gauche) conformer.