Preparation and characterization of various N-substituted-2-aza-[3]-ferrocenophanes and their chemical and electrochemical properties
摘要:
RuCl2(PPh3)(3) catalyzed condensation of 1,1'-ferrocenedimethanol with primary amines afforded N-alkyl- or N-aryl-2-aza-[3]-ferrocenophanes which were characterized by H-1 and C-13 NMR spectra. X-ray crystallography of N-(4-butylphenyl)-2-aza-[3]-ferrocenophane unequivocally revealed its mononuclear structure. The N-C (aryl) bond distance is shorter than the N-CH2 single bond due to extension of pi-conjugation of the aromatic ring to the nitrogen atom. N-Hexyl-2-aza-[3]-ferrocenophane reacts with methyl iodide to give the N-methylated product which was characterized by NMR spectroscopy and X-ray crystallography. N-Aryl-2-aza-[3]-ferrocenopbanes exhibited reversible redox between ferrocene and ferrocenium cations and an irreversible oxidation peak at a higher oxidation potential. (C) 1999 Elsevier Science S.A. All rights reserved.
Protonation of N-alkyl-2-aza[3]ferrocenophanes by HCl and NH4PF6 affords hexafluorophosphate salts having a trialkylammonium group. Structures of the protonated and unprotonated N-(p-methylbezyl)-2-aza[3]ferrocenophanes were determined by X-ray crystallography. Variable temperature C-13H-1} NMR spectra of the N-protonated N-hexyl-2-aza[3]ferrocenophane revealed inversion of the nitrogen of the 2-aza[3]ferrocenophane on the NMR time scale probably via partial deprotonation of the nitrogen atom. Cyclic voltammograms of the N-protonated compounds exhibited reversible redox peaks at higher potentials than those of the corresponding neutral ferrocenophanes. (c) 2006 Elsevier B.V. All rights reserved.