ABSTRACT
Precise frequencies for the 1(11)-2(02) transition of (33)SO(2) and SO(17)O in natural isotopic abundance have been obtained near 12 GHz by microwave Fourier transform spectroscopy in order to yield improved hyperfine constants. Nuclear spin-rotation coupling constants have been determined experimentally for (33)SO(2) for the first time. The spin-rotation constants have been used to derive nuclear magnetic shielding parameters. These parameters are compared with values for the isoelectronic O(3) molecule. The transition mentioned above was also measured for (32)SO(2), (34)SO(2), SO(18)O, and vibrationally excited (v(2) = 1) (32)SO(2). For (33)SO(2), some transitions with large hyperfine splitting were also recorded in the millimeter-wave region. Continuing our investigations of the rotational spectra of SO(2) in the submillimeter region, several transitions of SO(17)O have been recorded with the Cologne terahertz spectrometer between 540 and 840 GHz with J and K(a) up to 63 and 16, respectively. Transitions with high K(a), up to 28, have been recorded with the JPL laser sideband spectrometer between 1.8 and 3.2 THz. Copyright 2000 Academic Press.
ABSTRACT
The preparation of a series of novel Pt(IV) complexes containing the anionic polyfluoroaryl ligands, 2,3,5,6-tetrafluorophenyl (p-HC6F4), 2,3,5,6-tetrafluoro-4-methoxyphenyl (p-MeOC6F4) and pentafluorophenyl (C6F5) are described. The crystal structure of a representative complex, [Pt(p-MeOC6F4)2(O2CEt)2(en)] (en = ethane-1,2-diamine) was determined and confirms the trans arrangement of the carboxylato ligands. Reduction potentials of the series of complexes reveal that replacement of equatorial chloro ligands by polyfluoroaryl ligands makes reduction substantially more difficult. They also confirm previously reported trends in that complexes having axial carboxylato ligands are more readily reduced than those having axial hydroxo ligands. Reduction potentials and in vitro activities showed no obvious correlations. Moderate to high activity was observed for many complexes in the series, including some of those that were very difficult to reduce.
Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Organoplatinum Compounds/chemistry , Organoplatinum Compounds/pharmacology , Platinum Compounds/chemistry , Platinum Compounds/pharmacology , Animals , Anions , Crystallography, X-Ray , Drug Screening Assays, Antitumor , Electrochemistry/methods , Fluorine/chemistry , Inhibitory Concentration 50 , Leukemia L1210/drug therapy , Magnetic Resonance Spectroscopy , Mice , Mice, Inbred Strains , Molecular Structure , Oxidation-Reduction , Plasmacytoma/drug therapy , Platinum Compounds/chemical synthesis , Spectrum Analysis/methods , Structure-Activity RelationshipABSTRACT
Rotational spectra of the unstable molecules FBO, ClBO, and FBS have been measured in the 8-26 GHz frequency range using a pulsed jet cavity Fourier transform microwave spectrometer. The samples were prepared by passing electric discharges through mixtures of O2/BF3, O2/BCl3, or OCS/BF3, respectively, entrained in Ne. Hyperfine structures in the observed transitions have been resolved and analyzed in terms of nuclear quadrupole, spin-rotation, and spin-spin interactions. The quadrupole and spin-rotation coupling constants have been used to show that the electronic environment surrounding the boron nucleus of all three species is very similar. The spin-rotation constants have been used to determine, for the first time, experimental average shieldings of the Cl, F, and B nuclei of these molecules. Ab initio values for the nuclear shielding parameters have been calculated for comparison. Copyright 1998 Academic Press.
