Solid Adamantane Research Articles

Structure of Radicals Produced by γ-Radiolysis. Part 3. Radicals Derived from Adamantane, Adamantyl Derivatives, and Diamantane

The effects of γ-radiolysis on adamantane, perdeuterated adamantane, diamantane, 1- and 2-chloroadamantane, 1- and 2-bromoadamantane, 1-cyanoadamantane, 1- and 2-adamantanol, 1- and 2-adamantylamine have been examined via electron spin resonance techniques, and the nature of the predominant species produced is discussed. Spin-scavenging experiments using 2-methyl-2-nitrosopropane have been used, together with previously reported Br2 scavenging experiments, to identify the nature of the predominant species produced when purified solid adamantane is subjected to radiolysis. Data indicate that this is the 1-adamantyl radical. A possible reason for the controversial nature of data on this subject reported previously by other investigators is given.

High resolution pulsed nuclear double resonance analogue Fourier transform spectroscopy of dilute spins in solids

A method is described for the measurement of high resolution spectra of dilute spins in solids. It is a pulsed nuclear double resonance technique which uses the spin system to perform an analogue Fourier transform. Results on the 1.108% abundant 13C resonance in solid adamantane (C10H16) show a resolved doublet with a splitting of (36+or-5) Hz or (9.5+or-1.3) ppm and a residual linewidth of about 20 Hz.

Effect of pressure on molecular rotation in solid adamantane

The pressure dependence of the proton spin-lattice relaxation time has been measured in solid adamantane up to 4 kbar at different temperatures. The rotational correlation times were obtained as a function of temperature and pressure in the α-andβ-phases of adamantane. Hysteresis in the pressure-induced solid-solid transition has been observed.

Electron Spin Resonance of γ-Irradiated Acetylacetone in Adamantane Matrix

Electron spin resonance spectrum is observed when samples of solid adamantane doped with acetylacetone are γ-irradiated at room temperature. The spectrum is interpreted due to an enolized allylic radical CH3-COCHC(OH)CH2.

ESR spectrum of γ-irradiated adamantane

It has been shown that the ESR spectrum observed after γ irradiation of solid adamantane is not due to 1 and 2 adamantyl radicals but to a substituted 1 methyl cyclohexyl radical resulting from a C  C bond rupture. The reversible thermal changes of the spectrum show that the cyclohexyl ring inter-converts between its two stable configurations with a temperature dependent rate.

Electron Paramagnetic Resonance Study of some Alkyl Substituted Cycloalkenyl Radicals

Well-resolved electron spin resonance (e.s.r.) spectra are reported and analyzed for the radicals produced when samples of solid adamantane doped with alkyl substituted cycloalkenes are γ-irradiated at room temperature.

ESR spectra of γ-irradiated adamantane

ESR spectra of the 1- and 2-adamantyl radicals are reported in γ-irradiated solid adamantane and their relative stabilities discussed.

Dynamics of orientational defects in solid adamantane

By inelastic scattering of slow neutrons from solid adamantane (C10H16) it is found that in the high-temperature phase (T > 208K) the quasi-elastic distribution contains two components, a δ-function and a Lorentzian. A comparison of the latter component to model calculations suggests that it originates from dynamical orientation defects, i.e., rotational jumps of the molecules between equilibrium orientations. The relaxation time of this motion and its temperature dependence are determined and compared to n.m.r. observations. The theoretical model also predicts a distinct dependence of the scattering on the momentum transfer. With the help of this dependence the motion can be identified in detail.

Phonons, Torsons, and Rotational Diffusion in Adamantane

AbstractThe results of neutron spectroscopic measurements on solid adamantane (C10H16) are compared to calculated frequency distributions for phonons, torsons and mixed modes in the adamantane lattice. The comparison suggests that rotational diffusion jumps are superimposed on librational motions (torsons) and vibrations of the molecular centres of masses (phonons).

Confirmation of Phase Change in Solid Adamantane by NMR

Confirmation of Phase Change in Solid Adamantane by NMR

Nuclear Magnetic Resonance in Solid Adamantane

Proton magnetic resonance studies of solid adamantane reveal the existence of a rotational transition at about —130°C. The activation energy associated with the rotational transition is found to be about 5 kcal/mole. Theoretical and experimental second moments agree if it is assumed that the molecules are rigidly fixed below the transition and rotate freely above the transition.