Coronene—An ordered structure

It is shown that there is no disorder in coronene crystals at room temperature, and that the crystallographic data in the literature is of sufficient quality to show down less than 2% of disorder if it existed.     

Organic crystals absorb hydrogen gas under mild conditions

We have studied the hydrogen sorption on three well-known organic hosts that possess vacant lattice voids large enough to accommodate H2 molecules.     

The laser magnetic resonance spectrum of the NCO radical at 5.2 μm

Lines in the ν₃ (“antisymmetric” stretch) fundamental of the NCO radical in the $\text{X}\text{?}{}^2\text{Π}$ state were studied by CO laser magnetic resonance. The observations were assigned to P and R lines in the vibration-rotation band and lead to a precise determination of the vibrational interval and the anharmonic correction to the rotational constant: ν₃ = 1920.60645(19) cm^?1, α₃ = 0.003338(21) cm^?1. A single transition in the hot band (011)-(010), ${}^2\text{Δ}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Δ}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ was detected. This observation is used to determine the origin of the hot band as 1907.11892(20) cm^?1, i.e., the anharmonicity parameter x₂₃ = ?13.48753(28) cm^?1.     

A note on the motion of a viscous liquid in a rotating straight pipe

Résumé On fait une analyse de l'écoulement laminaire de liquides newtoniens dans des tuyaux cylindriques tournant autor d'un axe perpendiculaire à l'axe du tuyau, l'écoulement étant celui induit par un gradient de pression constant. On donne des calculs explicites dans les cas du luyau circulaire et du tuyau rectangulaire.     

Spiroketals: The synthesis of an olive fly pheromone component, 4-hydroxy-1,7-dioxaspiro[5,5]undecane, via a novle cation-olefin cyclisation step

An acid-catalysed rearrangement of the THP-ether of homoallylic alcohol gives ready access to an 0-protected derivative of 4-hydroxytetrahydropyran and thence by two further steps to provide a short and highly stereoselective route to the title spiroketal.     

Absorption spectrum of octahedral CoCl4(H2O)2 units in [(CH3)3NH]CoCl3·2H2O single crystal

The optical absorption spectrum of the octahedral moiety CoCl₄(H₂O)₂ in single crystal [(CH₃)₃NH]CoCl₃·2H₂O has been studied at room and liquidair temperatures. The observed ambient bands at 6800, 16,300, and 19,000 cm^–1 have been assigned, respectively, to the transitions⁴ T ₁(F) ⁴ T ₂(F),⁴ A ₂(F), and⁴ T ₁ (P). The crystal field parameters evaluated areD _q =B=850 cm^–1, andC=4.63B. At liquid-air temperatures the⁴ T ₁(P) band is seen to split into the expected four components ₇, ₈, ₈, and ₆, due to spin-orbit coupling, and the coupling coefficient was computed to be 525 cm^–1.     

Time-dependent-thermal-lensing (TDTL) studies on gas-phase azulene

Several aspects of the time-dependent-thermal-lensing (TDTL) technique were explored experimentally, including pressure effects, risetime behavior and falltime behavior. The experiments were performed using azulene vapor excited to high vibrational energies (≈ 17000 cm^?1). It was found that the energy appears in translational degrees of freedom at very early times, but the intrinsic limitations of the technique permitted only an estimate of the V-T rate constant for excited azulene deactivation by krypton. The result is discussed in terms of other recent experiments, and it is tentatively concluded that deactivation of excited azulene by unexcited azulene molecules may proceed primarily by a V-V process.     

The construction of orthogonalk-skeins and latink-cubes

Aequationes mathematicae -     

The Crystal and Molecular Structures of Two Acid-Catalysed Rearrangement Products of Taxochinon

The structures of two acid catalysed rearrangement products of taxochinone ( 1 ) have been determined by X-ray analysis. One of the products turned out to be a 20 (10→9) abeo-abietane ( 2 ), the other an optically inactive phenalenone ( 3 ). Crystals of the former compound, C₂₀H₂₆O₃, belong to space group P2₁2₁2₁ with four molecules per cell and the structure was refined with 879 significant reflexions to R = 0.032. Crystals of the latter compound, C₂₀H₂₂O₂, belong to space group P2₁/c with 12 molecules per cell and the structure was refined with 1823 significant reflexions to R = 0.058.