Craig D. Montgomery

STRUCTURES AND STRUCTURAL DISTORTIONS OF METALATED PHOSPHORANES

Abstract The 15 published crystal structures of metalated phosphoranes are reviewed. For 12 such structures, the distortion from a trigonal bipyramid towards a rectangular bipyramid and a 30° turnstile geometry is calculated using the method of dihedral angles. When compared to non-metalated phosphoranes, these metalated compounds exhibit a marked preference for the trigonal bipyramidal geometry. It is suggested here that this may be due to the π-donating abilities of the metal substituents. In a few cases, the metalated phosphorane structures also exhibit distortion along the turnstile coordinate as opposed to the Berry pseudorotation mechanism followed by non-metalated phosphoranes. This appears to be due to the considerable steric demands of the metal substituents in the equatorial plane of the phosphorane in these cases.

Infrared and Raman spectra of C6H6C6F6

Abstract The infrared and Raman spectra of C 6 H 6 C 6 F 6 are analyzed. In the vibrational region, only minimal shifts are observed, compared to C 6 H 6 and C 6 F 6 . For the low frequency lattice mode region, Raman spectra at 77 K and 20 K for C 6 H 6 C 6 F 6 are different from those of the individual molecules. For C 6 D 6 C 6 F 6 , the lower frequency lattice modes exhibit no deuterium shifts, while the higher ones move to lower energies. These results are interpreted in terms of weak coupling between partners in the complex.

A Convenient Route to Tetraalkylammonium Perfluoroalkoxides from Hydrofluoroethers

Hydrofluoroethers are shown to alkylate tertiary amines readily under solvent-free conditions, affording valuable tetraalkylammonium perfluoroalkoxides bearing α-fluorines. The reaction of R(F)CF2-OCH3 (R(F)=CF2CF3, CF2CF2CF3, and CF(CF3)2) with NR(1)R(2)R(3) produces twenty new α-perfluoroalkoxides, [(CH3)NR(1)R(2)R(3)][R(F)CF2O] under mild conditions. These α-perfluoroalkoxides are easy to handle, thermally stable, and can be used for the perfluoroalkoxylation of benzyl bromides.

Infrared spectrum of hexafluorobenzene crystal at 77 K

Abstract Infrared spectra of polycrystalline C 6 F 6 are analyzed in the 200 cm −1 to 4000 cm −1 region. The vibrational frequencies agree well with liquid data although many of the bands are split. Mutual exclusion between infrared active and Raman active fundamentals is found.

Synthesis and characterization of a copper amino-diphosphine complex that has an intramolecular hydrogen bond. X-ray structure of CuCl(PPh3)[NH(SiMe2CH2PPh2)2]

Abstract The compound CuCl(PPh 3 )[NH(SiMe 2 CH 2 PPh 2 ) 2 ] was prepared by the reaction of NH(SiMe 2 CH 2 PPh 2 ) 2 with CuCl(PPh 3 ) 3 and was characterized by 1 H and 31 P{ 1 H} NMR spectroscopy as well as X-ray crystallography. Crystals of the compound are triclinic, space group P 1 , a =11.657(1), b =19.273(1), c =11.0987(9) A, α =100.432(6), β =109.735(6), γ =94.157(7)°, Z =2. The structure was solved by the Patterson method and was refined with full-matrix least-squares procedures to R =0.039 and R w ( F 2 )=0.036 for 4719 reflections for which I >3 σ ( I ). The structure shows an unusual eight-membered chelate ring and an intramolecular hydrogen bond between the non-coordinated amine group and the chloride ligand.