MULTINUCLEAR SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE STUDY OF 2-AMINOETHYLFERROCENE AND ITS INTERCALATION COMPOUNDS WITH THE LAYERED HOST LATTICES MOO3 AND ALPHA-ZR(HPO4)2H2O

The isotopically labelled amino-functionalised ferrocene derivatives (FcCH2CH2NH2)-N-15 and Fc'CH2CH2NH2 [Fc = Fe(eta-C5H5)(eta-C5H4); Fc' = Fe(eta-C5D5)(eta-C5D4)] have been synthesized. Their hydrochloride salts and the lamellar intercalation compounds (MoO3(Fc'CH2CH2NH2)0.36)-N-15, and (Zr(HPO4)2(Fc'CH2CH2NH2)05(H2O).(x = 0.1-0.5))-N-15, have been studied by H-2, N-15 and, in the last case, P-31 solid-state NMR spectroscopy. H-2 NMR lineshape analysis has probed aspects of molecular dynamical behaviour. The H-2 NMR studies are consistent with rapid reorientation of the eta-C5D5 ring about the Fe-ring centroid axis. The deuterons of the eta-C5D4CH2CH2NH2 moiety appear to be static on the H-2 NMR timescale. Increased averaging of the lineshapes at higher temperatures is interpreted in terms of a rapid wobbling motion of the molecular pseudo-fivefold axis with near axial symmetry, and of progressively increasing amplitude with increase in temperature. Additionally, in the case of the hydrochloride salt and the MoO3 intercalate, but not the Zr(HPO4)2H2O intercalate, a vibration of the molecule in a plane perpendicular to the ferrocene molecular axis, in a manner whereby the molecules are 'anchored' at the substituent, is suggested. The N-15 CP/MAS NMR spectra reveal features of the host-guest bonding. The spectra of the intercalates are significantly different from those for (FcCH2CH2NH2)-N-15 and ([FcCH2CH2NH3]+Cl-)-N-15. For (MoO3(FcCH2CH2NH2)0.36)-N-15 the N-15 NMR shows two distinct environments for N-15 within the layers. The major resonance is apparently intermediate between that for ([FcCH2CH2NH3]+Cl-)-N-15 and (FcCH2CH2NH2)-N-15, whilst the other minor resonance has been tentatively assigned to a species resulting from oxidation of the guest molecules during the intercalation reaction. The N-15 and P-31 CP/MAS NMR spectra of (Zr(HPO4)2(FcCH2CH2NH2)0.5(H2O)x(x = 0.1-0.5)-N-15 support the hypothesis that the amine is interacting with the acidic layers through P-O ... H-N hydrogen bonds.