Multinuclear solid-state nuclear magnetic resonance study of 2-aminoethylferrocene and its intercalation compounds with the layered host lattices MoO3and α-Zr(HPO4)2H2O

Abstract

The isotopically labelled amino-functionalised ferrocene derivatives FcCH2CH215NH2 and Fc′CH2CH2NH2[Fc = Fe(η-C5H5)(η-C5H4); Fc′= Fe(η-C5D5)(η-C5D4)] have been synthesized. Their hydrochloride salts and the lamellar intercalation compounds MoO3(Fc′CH2CH215NH2)0.36, and Zr(HPO4)2(Fc′CH2CH215NH2)0.5(H2O)x(x= 0.1–0.5), have been studied by 2H, 15N and, in the last case, 31P solid-state NMR spectroscopy. 2H NMR lineshape analysis has probed aspects of molecular dynamical behaviour. The 2H NMR studies are consistent with rapid reorientation of the η-C5D5 ring about the Fe-ring centroid axis. The deuterons of the η-C5D4CH2CH2NH2 moiety appear to be static on the 2H 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.