Quercetin (3, 3', 4', 5, 7-pentahydroxyflavone) reacts with hexavalent
molybdenum, tungsten and chromium to form chelates soluble
in an ethanol-water medium. This color reaction has been investigated
with a view to its possible application in the spectrophotometric
determination of trace amounts of these metals.
In the development of the method,...
Bromoalkoxylation of dihydropyran with bromine and 1-borneol, followed by dehydrobromination and epoxidation, afforded trans-2-1- bornyloxy-3,4-epoxytetrahydropyran as a major product. This was treated with sodium phenylselenide to give a 1:1 mixture of (2R,3R,4R)- 2-1-bornyloxy-3-hydroxy-4-phenylselenotetrahydropyran and its (2S,3S, 4S) diastereomer. Elimination of the selenoxide, derived from oxidation of the former with hydrogen...
Analytical techniques are utilized in a wide variety of applications. Traditionally, analytical measurements are achieved by trained personnel in a laboratory setting using expensive scientific instruments, which limits their applicability in resource-limited areas and point-of-care applications. Therefore, the concept of enabling these laboratory-based qualitative and quantitative assays in microfluidic device...
Perdeutero-spiropentane (C₅D₈) has been synthesized and infrared and Raman spectra are reported for the first time. Wavenumber assignments are made for most of the fundamental vibrational modes. Gas phase infrared spectra were recorded at a resolution (0.002 cm⁻¹) sufficient to resolve individual rovibrational lines and show evidence of strong Coriolis...
In situ, reduction of Cp*ReO₃ by PPh₃ to form (Cp*ReO)₂(μ-O)₂ allows catalytic deoxygenation of epoxides, however, conproportionation between Reⱽ and Reⱽᴵᴵ species to form clusters of ((Cp*Re)₃(μ-O)₆}²⁺(ReO₄⁻)2 and new compound {(Cp*Re)₃(μ²-O)₃(μ³-O⁾³ReO₃}⁺(ReO₄⁻) leads to removal of rhenium from the catalytic cycle and loss of activity, The epoxide deoxygenation mediated by (Cp*ReO)₂(μ-O)₂...
At liquid nitrogen temperature the spectra of sublimed
films of NH₄NCS, both as phase I (the usual form stable at
room temperature) and phase II (the low temperature form),
exhibit detail usually reserved for gases at low pressures.
In both phases the symmetry of ammonium ion has degenerated
from tetrahedral...
The infrared absorption spectra in the out-of-plane
bending (v₂) region of potassium nitrate were studied for
three phases. Several types of sampled were used: nujol
mulls, fused samples, and N¹⁴-N¹⁵ isotopic mixtures. The
existence of three of the reported polymorphic phases was
confirmed by the spectra. The transitions between phase...
The development of a least squares model for the
determination of compliance constants from various combinations
of vibration frequency, mean square amplitudes
of vibration and centrifugal distortion data is discussed.
The resultant model is applied to frequency and mean square
amplitude data for NO₂ and N₂O₄ and to frequency and...
The ratio of the absolute infrared intensity, A₃/A₂, for the
parallel mode (2336 cm⁻¹) and the perpendicular mode (658 cm⁻¹)
of a nonpolar solute molecule, carbon dioxide, has been determined
in a nonpolar solvent, Nujol. The solution ratio (5.0) which has
been extrapolated to zero concentration is less than the...
Theoretical studies and experimental results are presented for the rotational motion of molecule's in crystalline solids. The group theory is solved for molecules of any symmetry matrix isolated at a site in a crystal field of any symmetry. As the potential terrier to rotation of the molecule relative to the...
A spectral investigation of the molecular vibration region of
the potassium sulfate crystal system was undertaken. This study was
initiated to establish the feasibility of using this crystal as a
host matrix for ammonium sulfate. Since these two systems are isomorphic
and have unit cells of nearly equal volume the...
The spectrophone method for the study of vibrational relaxation
has been claimed to possess a distinct advantage over the more commonly
used ultrasonic techniques in that it permits the relaxation of
the various infrared-active vibrational modes in a polyatomic molecule
to be studied separately. A discussion of the rate equations...
The velocity of sound in gases was measured, using an ultrasonic
wave train as a diffraction grating. The fundamental problems
involved in the optical technique are discussed. An apparatus utilizing
an objective lens of focal length 1.5 m and aperture f/20 was constructed
and used at an ultrasonic frequency close...
Studies of anisotropic and isotropic Raman line shape yield information about the rotational motion (rotational correlation function) and non-reorientational (vibrational) lifetimes. The rotational motion of carbon disulfide has been studied previously by the techniques of Raman spectroscopy (6, 43), Rayleigh scattering (43, 46) and direct measurement (47). This work was...
A study was made of the infrared absorption spectrum for
cyanate ion in KCl and KBr host lattices containing small amounts of
calcium or barium ion. Both pellets and single crystals were
scanned during the course of this study. The spectra of the barium
or calcium doped crystals contained many...
The infrared spectra of liquid and solid films of
formaldehyde were taken over the range of 35 to 4,000 cm⁻¹
using Beckman IR 7 and IR 11 spectrometers. A new overtone
band and a new combination band were found as well as three
fundamental peaks due to lattice vibrations and...
The infrared absorption spectrum from 3200 cm⁻¹ to 4025
cm⁻¹ of thin crystals of ⁶LiOH (99%⁶Li.) is presented and compared
to the spectrum of [superscript]NLiOH (93%⁷Li). A shift in only one of the band
pairs supports the lattice combinations model and assists in making
assignments for the major features of...