The microwave spectrum and structure of krypton--phosphorus trifluoride

The rotational spectrum of the weak complex between krypton and phosphorus trifluoride has been observed using a Fourier transform microwave spectrometer with a pulsed supersonic nozzle molecular beam source. The complex is an asymmetric top. The distance rcm between the krypton atom and the center of mass of the PF3 molecule is 4.0722 A and the angle between the rcm vector and the C3 axis of the PF3 is 68.25[deg]. Based on the centrifugal distortion constant DJ and a pseudodiatomic model, the binding energy of the complex is estimated to be 218 cm-1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27096/1/0000087.pd

Molecular structures of gas‐phase polyatomic molecules determined by spectroscopic methods

Spectroscopic data related to the structures of polyatomic molecules in the gas phase have been reviewed, critically evaluated, and compiled. All reported bond distances and angles have been classified as equilibrium (re), average (rz), substitution (rs), or effective (ro) parameters, and have been given a quality rating which is a measure of the parameter uncertainty. The surveyed literature includes work from all of the areas of gas‐phase spectroscopy from which precise quantitative structural information can be derived. Introductory material includes definitions of the various types of parameters and a description of the evaluation procedure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87746/2/619_1.pd

The chlorine nuclear quadrupole coupling tensor in chlorotrifluoroethylene

The 273 hyperfine components from 56 rotational transitions of chlorotrifluoroethylene were measured with a Fourier transform microwave spectrometer. A global least-squares fit was made to the rotational constants, quartic distortion constants, and 35Cl quadrupole coupling constants; the RMS deviation of the fit was 1.6 kHz. It is shown that such high-resolution measurements enable [chi]ab to be determined without the near degeneracies usually necessary with less precise data. The principle tensor quadrupole coupling constants are x[chi]zz = -77.46(10), xxx = 38.85(10), and [chi]yy = xcc = 38.614(3) MHz. The values are comparable to other vinyl chlorides, removing some anomalies from previous studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27550/1/0000594.pd

The microwave spectrum, structure and dipole moment of 1,4-pentadiyne

The microwave spectra of 1,4-pentadiyne and 1,4-pentadiyne-1,5-d2 are assigned and rotational and centrifugal distortion constants obtained. A unique structure could not be determined. However, analysis of the moments of inertia indicates that the bond distances in C5H4 are close to typical values found in other related compounds. An interaction involving the acetylene moieties is evidenced by the derived bond angles. The data are consistent with either the central CCC angle being close to the tetrahedral value with the acetylene groups pushed away from linearity by approximately 3-4[deg] or opening of the central CCC angle to about 113[deg] along with linear acetylene groups. A range of structures between these two is also possible. The dipole moment is determined to be 0.516(5) D.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24440/1/0000713.pd

Tandem application of C-C bond-forming reactions with reductive ozonolysis

Several variants of reductive ozonolysis, defined here as the in situ generation of aldehydes or ketones during ozonolytic cleavage of alkenes, are demonstrated to work effectively in tandem with a number of C-C bond-forming reactions. For reactions involving basic nucleophiles (1,2- addition of Grignard reagents, Wittig or Horner-Emmons olefinations, and directed Aldol reactions of lithium enolates) the one-pot process offers a rapid and high-yielding alternative to traditional two-step protocols

Pregnancy, prescription medicines and the potential risk of herb-drug interactions:a cross-sectional survey

Funding All funding was from institutional resource. JSM, AS are employed by the University of Aberdeen. DS is employed by the Robert Gordon University. BP and CR are employed by NHS Scotland. ARP and MAH are employed by the Hamad Medical Corporation. Qatar. NI is a postgraduate student at the University of Aberdeen.Peer reviewedPublisher PD

THE MICROWAVE SPECTRUM OF DIFLUOROPHOSPHINE (HPF2)(HPF_{2})

Author Institution: Department of Chemistry, University of MichiganEighteen transitions have been assigned for $HPF_{2}$. The rotational constants are: $A = 24551.63 Mc., B = 8895.55 Mc., C = 6854.02 Mc$. The spectrum of $DPF_{2}$ is currently being measured and assigned. The detailed structure of this pyramidal molecule will be discussed

MICROWAVE SPECTRA AND STRUCTURE OP S2F2∗S_{2}F_{2}^{*}

$^{*}$The research was made possible by support extended Harvard University by the Office of Naval Research under ONR Contract Nonr 1866, Task Order XIV.Author Institution: Department of Chemistry, Harvard University“By employing mass spectroscopy, low temperature distillation and microwave spectroscopy, one component of the mixture of gases generated by heating AgF and sulfur has been identified as $S_{2}F_{2}$ with structure analogous to thionyl fluoride $(SOF_{2})$. The relative mass spectral cracking pattern found for $S_{2}^{32}F_{2}$ was $S_{2} F_{2}{^{+}} = 100; S_{2} F{^{+}} = 30.2;\ SF_{2}{^{+}} = 7.4;\ S_{2}{^{+}} = 23.2;\; SF{^{+}} (S_{2} F_{2}{^{++}}) = 6.6;\ S{^{+}} (S_{2}{^{++}})= 26.6;\ F{^{+}} = 2.6;\ S_{2} F{^{++}}\sim 0.6;\ SF_{2}{^{++}} < 0.1.$. Three sulfur isotope species were identified in the microwave spectra. Strong \emph{c} dipole transitions and weak \emph{a} dipole transitions were observed. The rotational constants are: [FIGURE] The structural parametrs are $d(S = S) = 1.86 \pm 0.03${\AA}; $d(S - F) = 1.59 \pm 0.03${\AA}; $\angle FSF = 92^{\circ} \pm 1^{\circ};\;\angle SSF = 108.5^{\circ} \pm 1.5^{\circ}$. Evidence for the existence of another molecule with empirical formula $S_{2}F_{2}$ will be discussed.