The rotational and fine-structure spectrum of FeH, studied by far-infrared laser magnetic resonance

Transitions between the spin-rotational levels of the FeH radical in the upsilon=0 level of the X (4)Delta ground state have been detected by the technique of laser magnetic resonance at far-infrared wavelengths. Both pure rotational and fine-structure transitions have been observed; lambda-type doubling is resolved on all the observed transitions. The energy levels of FeH are strongly affected by the breakdown of the Born-Oppenheimer approximation and cannot be modeled accurately by an effective Hamiltonian. The data are therefore fitted to an empirical formula to yield term values and g factors for the various spin-rotational levels involved. Many of the resonances show a doubling that arises from the proton hyperfine structure. These splittings are analyzed in a similar manner.     

Far-infrared spectrum of anthraquinone single crystal

Far-infrared, polarized spectra of 9,10-anthraquinone as a single crystal have been measured at room and liquid-nitrogen temperatures. The observed bands have been assigned to translational lattice vibrations on the basis of polarization results of a normal-coordinate calculation. A peculiar effect of temperature on the spectra has been found and suggested to be due to Fermi resonance involving the lattice vibrations.     

The proton magnetic resonance spectrum of amphotericin B

The high resolution proton NMR spectrum of Amphotericin B in dimethyl sulphoxide has been analysed by a combination of spin decoupling. NOE difference and spin decoupling difference techniques. The parameters are compared with those obtained for the related macrolide antibiotic pimaricin, and the methyl ester and acetamide of Amphotericin B.     

The proton magnetic resonance spectrum of 1-methylpyrazole

5-Deutero-1-methylpyrazole was synthesised and used to assign multiplets in the PMR spectrum of 1-methylpyrazole.     

Carbon-13 nuclear magnetic resonance spectrum of methaqualone

¹³C nmr chemical shifts of methaqualone, 2-methyl-3-propyl-4-quinazolone, 2-methyl-3-phenyl-4-quinazolone and their precursor, acetanthranil, are reported. The signals are assigned on the basis of suhstituent effects on benzene shifts, intensities, multiplicities in SFORD, and comparison with structurally related compounds.     

Far-infrared laser magnetic resonance spectrum of SeD (X2Π32)

Far-infrared laser magnetic resonance (LMR) spectra of SeD have been detected at 513 μm using a formic acid laser, and assigned to Zeeman components of the J = $\text{3}\text{2}$ → $\text{5}\text{2}$ transition in the six isotopic forms ^{82,80,78,77,76,74}SeD. Analysis yields the following B_o constants (cm^?1): ⁸²SeD 3.96047, ⁸⁰SeD 3.96284, ⁷⁸SeD 3.96532, ⁷⁷SeD 3.96657, ⁷⁶SeD 3.96793 and ⁷⁴SeD 3.97066. These values, combined with B_o for ⁸⁰SeH from 5.6μm LMR, yield r_e = 0.14634 nm for SeD.     

The fluorine magnetic resonance spectrum of poly(vinyl fluoride)

High resolution fluorine magnetic resonance spectra have been obtained for poly(vinyl fluoride) at elevated temperature. Proton noise-decoupling and time-averaging techniques have given new tacticity and sequence information.     

Proton magnetic resonance spectrum of thiophen dissolved in a nematic solvent

The PMR spectrum of thiophen dissolved in a nematic phase is reported. This spectrum has been analysed iteratively. The ratios of the various inter-proton distances determined in this study are in good agreement with those previously reported.     

The AsO radical detected by infrared laser magnetic resonance

The Pauli master equation for intramolecular vibrational relaxation and the heat bath feedback Bloch equations for radiative pumping of polyatomic molecules can be derived by replacing the standard assumption of random matrix element coupling between zero-order vibrational states by an assumption that relaxation is governed by restricted quantum exchange.     

On the nuclear magnetic resonance spectrum of reduced nicotinamide adenine dinucleotide

The two C-4 protons of reduced nicotinamide adenine dinucleotide (NADH) produce an AB NMR spectrum at 100 MHz as well as at 220 MHz. This observation allows an upper limit of 50 sec^?1 to be placed on the mean rate of interconversion of the two folded forms of NADH invoked to account for the magnetic non-equivalence of the C-4 protons. The interpretation of non-equivalence of the C-4 protons in terms of the various equilibria among folded and unfolded forms of NADH and its possible significance in the mechanism of action of dehydrogenase enzymes is discussed. It is suggested that one folded form of NADH is strongly favored thermodynamically over the other and that the resulting magnetic non-equivalence of the C-4 protons is of doubtful significance in explaining the stereospecificity of dehydrogenase enzymes toward the nicotinamide ring.     

Laser magnetic resonance spectrum of the PH2 radical

The PH₂ radical in its ground vibrational and electronic state has been detected by far infrared laser magnetic resonance absorption using the 118.6 μm line of the water vapour laser. The spectrum has been assigned to Zeeman components of the 5₃₂ – 6₄₃ rotational transition.     

Proton magnetic resonance spectrum of polysilazane obtained by transamination of hexamethylcyclotrisilazane with ethylenediamine

The PMR spectrum of the product of reaction of hexamethylcyclotrisilizane with ethylenediamine is investigated, and shows that both linear-ladder and linear polysilazane can arise from the transamination reaction.     

Applications of nuclear magnetic resonance in biochemistry: An analysis of the aromatic region of the proton magnetic resonance spectrum of staphylococcal nuclease

Summary General procedures for the simplification and analysis of nuclear magnetic resonance spectra of proteins are presented. These are illustrated with current results with the enzyme staphylococcal nuclease which have permitted a partial analysis of the aromatic region of its proton nuclear magnetic resonance spectrum.

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Zusammenfassung Allgemeine Verfahren zur Auswertung und Vereinfachung der kernmagnetischen Resonanzspektren von Proteinen werden diskutiert und an Hand neuer Ergebnisse mit dem Enzym Staphylococcus-Nuclease demonstriert. Bei diesem Enzym gelang eine Teilanalyse des aromatischen Bereichs des KMR-Spektrums.

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Abbreviations used Nase Staphylococcal nuclease from Foggi strain - Nase-Dl selectively deuterated analog of Nase in which all amino acids except the following are deuterated — (1) Trp; (2) Met; (3) Tyr in ring positions 2 and 6; (4) His in ring methine 2; (5) Asx -methylene; and (6) Glx -methylene - HMS hexamethyldisiloxane - CAT computer of average transients - EDTA ethylendiaminetetraacetate     

A double-modulation laser magnetic resonance spectrometer using a differential gated integrator

A double-modulation differential gated integration system was applied to a laser magnetic resonance spectrometer. The long-term stability of the spectrometer was sufficient to improve greatly the signal-to-noise ratio for large integration time constants. Detection of weak spectral lines of free radicals was demonstrated.     

Assignment and solvent dependence of the carbon-13 nuclear magnetic resonance spectrum of nicotine

The ¹³C nmr spectrum of nicotine is assigned in Acetone-d₆, DMSO-d₆, Pyridine-d₅, and deuterium oxide (pD 10.7, 5.4, < 1). Attention is focused on assignment of the closely-spaced C(2) and C(6) resonances, using selective decoupling, population transfer, and long-range coupling constant measurements. C(2) resonates at lower field in the organic solvents hut at higher field in deuterium oxide at all pD values investigated.