RESUMEN
Recent synthetic and theoretical investigations of organometallic compounds containing the CpCr(NO) fragment have shown an interdependence of the electronic nature of ancillary ligands and the stability of a given Cr oxidation state. Understanding the correlation between ligand pi-bonding properties and the nature of the metal-based frontier orbitals permits the rationalization of observed reactivity patterns, and the identification and preparation of new classes of target molecules.
RESUMEN
High-resolution FTIR spectra of 1,1,1-trifluoroethane (HFC-143a) have been recorded in the region from 1370 to 1470 cm(-1) with an unapodized resolution of 0.0016 cm(-1) at room temperature and of 0.004 cm(-1) at 183 and 100 K. The two main infrared active bands of A(1) symmetry have been shown to be nu(2) at 1407.5 cm(-1) and nu(4) + nu(5) at 1440.5 cm(-1). With the aid of Raman spectra, the two infrared inactive bands of E symmetry in this spectra region have been shown to be nu(8) at 1457.5 cm(-1) and nu(6) + nu(9) at 1446.2 cm(-1). The nu(2) band was analyzed as an isolated band, whereas the nu(4) + nu(5) band was analyzed as part of the triad nu(4) + nu(5), nu(6) + nu(9), and nu(8). Copyright 2000 Academic Press.
RESUMEN
A dimeric structure that is held together by hydrogen bonds and is stable in solution is adopted by the hydrochloride salt of the expanded corrole shown. The synthesis, X-ray structure, and NMR and electronic absorption spectra of the new species all confirm the structural assignment in solution and in the solid state.
RESUMEN
High-resolution (up to 0.0016 cm-1 unapodized) room temperature and collision-cooled (at approximately 100 K) mid-infrared (1000-1300 cm-1, 7.7-10 µm) absorption measurements of the nu3 and nu9 vibrational bands of difluoromethane (CH2F2, HFC-32) vapor were made with a Fourier transform spectrometer. A ro-vibrational analysis of over 900 infrared transitions has yielded quartic rotational constants, and the C-type Coriolis coupling xic39 = 0.28802(11) cm-1. The results are compared with a previous analysis [J. Matuszeski and M. Marshall, Spectrochim. Acta. A 52, 1069-1077 (1996)] of a jet-cooled spectrum. Copyright 1999 Academic Press.