Mono- and difluorinated 1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophanes (AF4s)-A (1)H and (19)F NMR study. 2009

Ion Ghiviriga, and Florian Dulong, and William R Dolbier
University of Florida, Chemistry Department, Gainesville, FL-32611-7200, USA. ion@chem.ufl.edu

Complete assignment of the (1)H and (19)F chemical shifts in 4-fluoro-AF4 (1) were based on the nOes seen in its (19)F-(1)H HOESY spectrum. This allowed for identification of features which can further be applied to the assignment of the regiochemistry of substituted perfluoroparacyclophanes (PCPs) and AF4s: (i) an aromatic fluorine couples with the two fluorines in the closest bridge that are syn to it, with constants of ca. 20 Hz; (ii) an aromatic fluorine couples with the bridge fluorine five bonds away that is anti to it in the same paraphenylene moiety, with a constant of ca. 3.5 Hz; (iii) the geminal coupling of the bridge fluorines is 246 Hz if they have an ortho fluorine and 238 Hz if they do not; (iv) a bridge fluorine couples with those aromatic protons in the same paraphenylene moiety that are four or five bonds away and anti. These features have been used to assign the regiochemistry of the pseudo-ortho, pseudo-meta and pseudo-para-difluoro AF4s 2-4. It has also been demonstrated that SCS for the bridge fluorines can be used as well for this assignment.

UI MeSH Term Description Entries
D008968 Molecular Conformation The characteristic three-dimensional shape of a molecule. Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D009682 Magnetic Resonance Spectroscopy Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING). In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D011522 Protons Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion. Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D001952 Bridged-Ring Compounds Cyclic hydrocarbons that contain multiple rings which share one or more bridgehead connections. Bridged Compounds,Bridged Ring Compounds
D005461 Fluorine A nonmetallic, diatomic gas that is a trace element and member of the halogen family. It is used in dentistry as fluoride (FLUORIDES) to prevent dental caries. Fluorine-19,Fluorine 19
D013237 Stereoisomerism The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed) Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer

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