A computer-based spectrophotometric study of the kinetics of the aquation of halogenopentammine-chromium(III) perchlorate

Conventional determinations of rate constants k from absorption spectra employ a few selected wavelengths: by digitizing the complete spectrum computer calculations of k can be made at most wavelengths, and hence with better precision. This has here been satisfactorily tested for the aquation of halogenopentamminechromium(III) perchlorate. Two independent procedures are described, which are approximately equally onerous on computer time. Additionally, these procedures are shown to yield identical computer-generated spectra for the halogeno-complex before aquation commences, and accurate time infinity spectra, of the aquo-complex, for long half-life reactions. They also efficiently eliminate the effects of spectrophotometer instability over long periods of time.     

Die Kristallstruktur und absolute Konfiguration von Mikrolin

The Crystal Structure and Absolute Configuration of Mikrolin. The crystal structure and absolute configuration of mikrolin has been determined by X-ray diffraction. Crystals of mikrolin belong to space group P2₁2₁2₁ with a = 17.867, b = 7.947, c = 9.824 Å, Z = 4. The structure was solved by multi-solution method, and refined to R = 0.060. The anomalous scattering of CuKα-radiation by chlorine was used to determine the absolute configuration of the molecule.     

The distance separating quantum theory from reality

A local realistic model of optical cascades, involving just one angular hidden variable, is found to give a coincidence curve which differs from the quantum-theoretic curve by an average of 1.5% for currently realizable experiments. The results indicates that it is extremely difficult, though not impossible, to use such experiments to discriminate between quantum theory and local realistic theories. However, in no experiment performed to date has sufficient accuracy been achieved to make such a discrimination.     

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.