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More than 160 new hyperfine components of rotational transitions of the free fluoroformyloxyl radical FCO2· have been measured using the Prague millimeter wave high resolution spectrometer. The frequencies of these transitions together with the previously measured data were analyzed in detail and precise values of magnetic hyperfine and fine parameters were obtained. These new parameters significantly improve the values of previously determined hyperfine parameters which were rather unreliable. The new fine and hyperfine parameters obtained in this study are compatible with those of the simultaneously electron paramagnetic resonance study. Besides that, significantly improved ground state rotational and centrifugal distortion constants of the fluoroformyloxyl radical were derived. [ABSTRACT FROM AUTHOR]

FC(O)Br has been synthesized, and its IR spectrum in the gas phase and isolated in an Ar matrix, as well as, its Raman spectrum in the solid state at -196 °C has been analyzed. Its molecular structure has been determined and its UV has been measured. FC(O)Br and FC(O)Cl has been photodissociated in an argon matrix at 17 K with a 193 nm laser. The photolysis produces CO and XF which recombine to form CO/XF complexes. The formation of complexes are followed by the shift of the normal vibration modes with respect to CO and XF isolated in argon matrix. In the case of FC(O)Br, three isomers are identified, OC...BrF, OC...FBr, and CO...BrF, whereas for FC(O)Cl only one isomer is observed, OC...ClF. High level quantum chemical calculations are used to help the assignment of the different isomers. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The novel iminyl radical O2SN, a SO3 analogue, was produced by flash vacuum pyrolysis of gaseous alkyl sulfonyl azides RSO2N3 (R=CF3, CH3) mixed with argon. Photoisomerization (λ>360 nm) of O2SN into planar syn‐OSNO and anti‐OSNO (see picture) was observed in solid noble‐gas matrices. [ABSTRACT FROM AUTHOR]

A convenient one-step synthesis for [Mn(CO)6]+ salts has been developed. The method involves the one-electron oxidation of Mn2(CO)10 by protons in solutions of Lewis acids (BF3, (CF3)3BCO) and anhydrous HF. The molecular structure of [Mn(CO)6][BF4]·SO2 was determined by single-crystal X-ray diffraction. Crystal data: orthorhombic, space group Cmc21; a = 8.7001(2) Å, b = 11.8497(3) Å, and c = 11.7437(3) Å; Z= 4; R1 = 0.0320 and wR2 = 0.1106. The structural, NMR, and vibrational spectroscopic properties of [Mn(CO)6]+ fit perfectly with those of the isoelectronic species [V(CO)6]-, Cr(CO)6, and [Fe(CO)6]2+. [ABSTRACT FROM AUTHOR]

Treatment of Cs[(CF3)3BNH2] with the aminating agent H2NOSO3H in aqueous solution allowed the isolation of pure Cs[(CF3)3BH], which is stable up to 300 °C. Due to the strong electron-withdrawing effect of the CF3 substituents, the [(CF3)3BH]- anion behaves as a very unreactive hydride. It is stable in concentrated hydrochloric acid for many days but reacts cleanly with F2, CI2, and Br2 to the corresponding haloborates. The molecular structure was determined by single-crystal X-ray diffraction. Crystal data: orthorhombic, space group Pnrna; a = 11.4296(5) Å, b = 7.9510(4) Å, c = 9.7268(5) Å; V = 883.94(7) Å3, Z = 4; R1 = 0.0294, wR2 = 0.0818. The anions exhibit only Cs symmetry in the lattice. The natural and deuterated anions were characterized by IR, Raman, and multinuclear NMR spectroscopy; vibrational assignments were supported by DFT calculations. QTAIM charges derived from the B3LYP electron density are given for [(CF3)3BH]- and several related anions. [ABSTRACT FROM AUTHOR]

Fluoroformyl trifluoroacetyl disulfide, FC(O)SSC(O)CF3, is prepared by quantitative reaction between FC(O)SCl and CF3C(O)SH. The conformational properties and geometric structure of the gaseous molecule have been studied by vibrational spectroscopy (IR(gas), Raman(liquid), IR(matrix)), gas electron diffraction (GED), and quantum chemical calculations (B3LYP and MP2 methods). The disulfide bond length derived from the GED analysis amounts 2.023(3) Å, and the dihedral angle around this bond, ϕ(CS-SC), is 77.7(21)°, being the smallest dihedral angle measured for noncyclic disulfides in the gas phase. The compound exhibits a conformational equilibrium at room temperature having the most stable form C1 symmetry with a synperiplanar (sp-sp) orientation of both carbonyl groups with respect to the disulfide bond. A second form was observed in IR spectra of the Ar matrix isolated compound at cryogenic temperatures, corresponding to a conformer that possess the carbonyl bond of the FC(O) moiety in antiperiplanar position with respect to the S-S single bond (ap-sp). A ΔH° = H°(ap-sp) - H°(sp-sp) = 1.34(11) kcal/ mol has been determined by IR(matrix) spectroscopy. The structure of single crystal of FC(O)SSC(O)CF3 was determinate by X-ray diffraction analysis at low temperature using a miniature zone melting procedure. The crystalline solid (monoclinic, P21/n, a = 5.240(4)Å, b = 23.319(17)Å, c = 6.196(4)Å, β = 113.14(3)°) consists exclusively of the (sp-sp) conformation. The geometrical parameters agree with those obtained for the molecule in the gas phase. [ABSTRACT FROM AUTHOR]

More than 160 new hyperfine components of rotational transitions of the free fluoroformyloxyl radical FCO2· have been measured using the Prague millimeter wave high resolution spectrometer. The frequencies of these transitions together with the previously measured data were analyzed in detail and precise values of magnetic hyperfine and fine parameters were obtained. These new parameters significantly improve the values of previously determined hyperfine parameters which were rather unreliable. The new fine and hyperfine parameters obtained in this study are compatible with those of the simultaneously electron paramagnetic resonance study. Besides that, significantly improved ground state rotational and centrifugal distortion constants of the fluoroformyloxyl radical were derived. [ABSTRACT FROM AUTHOR]

Chlorodifluoroacetyl isocyanate, ClF2CC(O)NCO,was preparedby the reaction of ClF2CC(O)Cl with excess of AgNCO. Thecolorless compound melts at −83 °C and the vapor pressurefollows the equation ln p= −3868.3 (1/T) + 10.89 (p[Atm], T[K]) in the range −38 to +22 °C, extrapolated bp ca.82 °C. It has been characterized by IR (gas phase, Ar matrix),liquid Raman, 19F and 13C NMR, gas UV–visspectrum, photoelectron spectroscopy (PES), photoionization mass spectrometry(PIMS), and gas electron diffraction (GED). The matrix photochemistryhas been studied and the conformational properties of ClF2CC(O)NCO have been analyzed by joint application of vibrational spectroscopy,GED, and quantum chemical calculations. Two conformers were detectedin gaseous and liquid phases, in which the C–Cl bond adoptsa gauche orientation with respect to the CO group, whereasthis group can be in syn or anti orientation with respect to the NCbond of the NCO group. An enthalpy difference ΔHexp°=1.3 ± 0.2 kcal mol–1between the most stablesyn–gauche and the less stable anti-gauche form was derivedusing the van’t Hoff equation, which is in reasonable agreementwith the computed difference of ΔH° =0.8 kcal mol–1(B3LYP/6-311+G(3df) approximation).The most significant gas phase structural parameters for gauche–synClF2CC(O)NCO are re(NCO)= 1.157(1) Å, re(NCO) = 1.218(1)Å, re(N–C) = 1.378(9) Å, re(CO) = 1.195(1) Å, ∠e(CNC) = 128.6(19)°. Photolysis of ClF2CC(O)NCOusing an ArF excimer laser (193 nm) mainly yield ClF2CNCOalong with some ClF2CC(O)N nitrene. The valence electronicproperties of the title compound were studied using the PES and PIMS.The experimental first vertical ionization energy of 11.54 eV correspondsto the ejection of a carbonylic oxygen lone pair electron. [ABSTRACT FROM AUTHOR]

Sulfuryl diazide, O2S(N3)2, previously described as an "exceedingly explosive" compound, has been isolated and characterized by IR (Ar matrix, gas) and Raman (solid) spectroscopy, and its structure has been determined by X-ray crystallography. It has a melting point of -15 ¼C and can be handled in small quantities in gas, liquid, and solid states. Vibrational spectroscopic studies suggest the presence of only one conformer in both gas and solid states, and the X-ray crystallography revealed an anti conformation of the two azido groups with respect to the NSN plane. Calculations predict the anti (C2) conformer to be 6.6 kJ mol-1 lower in energy than the syn (Cs) one at the CBS-QB3 level of theory. The related chlorosulfuryl azide, ClSO2N3, has also been prepared and characterized by IR and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Fluorocarbonyl thio- and isothiocyanate, FC(O)SCN and FC(O)NCS, were fully characterized by IR (gas, Ar and N2 matrixes), Raman (liquid and solid), UV (gas), and 13C NMR (liquid) spectroscopy, as well as single-crystal X-ray diffraction. Their vibrational and conformational properties were analyzed using matrix isolation techniques guided by quantum chemical calculation at the ab initio [MP2 and CCSD(T)], density functional theory B3LYP, and CBS-QB3 levels of theory. A complete assignment of the fundamental modes of FC(O)SCN was performed. In both the gas and liquid states, FC(O)SCN and FC(O)NCS were found to exist as two conformers (Cs symmetry), in which the carbonyl double bond (CO) adopts a synperiplanar (syn) and an antiperiplanar (anti) orientation with respect to either the SCN or NCS group. For FC(O)SCN, the conformational enthalpy difference, ΔH° = H°(anti) - H°(syn), was determined by matrix IR experiments to be 0.9 ± 0.2 kcal mol-1. The conformational equilibria were evaluated by fast-cooling gaseous samples highly diluted in argon at different temperatures as cryogenic matrixes. The conformational properties of both molecules were analyzed in terms of the hyperconjugative electronic effect applying the natural bond orbital method. The kinetics of the thermal conversion of the high-energy anti into the syn FC(O)NCS conformer was studied in Ar and N2 matrixes at cryogenic temperatures. The reversed syn → anti photoisomerization was observed using UV-vis light. Rearrangement of FC(O)SCN into FC(O)NCS was observed in the neat liquid and in solution. Under 193 nm (ArF excimer laser) irradiation, FC(O)NCS isolated in cryogenic Ar matrixes forms FC(O)SCN. At low temperature, single crystals of the two constitutional isomers were obtained using a miniature zone melting procedure. According to X-ray diffraction, they exclusively crystallize in their syn forms (Cs symmetry) in the orthorhombic crystal system. [ABSTRACT FROM AUTHOR]

Studies the geometric structure and conformational properties of trifluoromethyl chlorosulfonate using X-ray crystallography, gas electron diffraction and vibrational spectroscopy. Chemical bonds; Molecular orientation; Gas phase and crystal structure.

Discusses the synthesis and structural characterization of a structurally characterized salt with a tripositive, homoleptic metal carbonyl cation. Crystallographic data; Vibrational spectra; Molecular structure.