62331-74-2Relevant academic research and scientific papers
Coordination Chemistry with CF Units as σ Donors: Ag+ of Partially Fluorinated Crown Ethers Direct Metal-Fluorine Interactions
Plenio, Herbert,Diodone, Ralph
, p. 1211 - 1217 (1996)
The partially fluorinated cryptands FM2O4 and BenzoFN2O4 which are relatives of the [2.2.1]cryptand, were synthesized in good yields from l,3-bis(bromomethyl)-2-fluorobenzene and diaza-18-crown-6 or benzodiaza-18-crown-6, respectively. These macrobicyclic ligands form very stable complexes with Ag(I) salts, and it was shown that close fluorinesilver interactions occur in solution as well as in the solid state. Numerous experimental evidence for this is available: NMR competition experiments show that Ag+ complexes of FN2O4 are significantly more stable than those of HN2O4 (the two ligands are identical except that one fluorine atom is replaced by one hydrogen atom in HN2O4); the 1JCF coupling constants of Ag+ ·FN2O4 and Ag+ · BenzoFM2O4 are reduced by 10 Hz compared to those of the respective free ligands FN2O4 (1JCF = 253 Hz) and BenzoFN2O4. (1JCF = 252 Hz). The X-ray crystal structure of Ag+ ·FN2O4 reveals short Ag+-F distances [271,4(3) pm]; coupling of the 107,109Ag+ and 19F nuclei is observed in the 19F-NMR spectra (J = 24 Hz for Ag+ · FN2O4, J= 25 Hz for Ag+ ·BenzoFN2O4). The 1H-NMR spectrum of Ag+ ·FN2O4 is very complex and exhibits sixteen unique proton resonances, whose evaluation yielded coupling constants and NOEs, which show that the structure in solution is compatible with the results obtained by the X-ray crystal structure determination. VCH Verlagsgesellschaft mbH 1996.
