Naphtho[1,2-c:5,6-c]difuran: a reactive linker and cyclophane precursor

Naphtho[1,2-c:5,6-c]difuran has been isolated in a 9-step synthesis from 2,6-dimethylnaphthalene. It is a highly reactive diene similar in nature to the related isobenzofuran. In Diels-Alder reactions, its intermediate monoadducts are actually less reactive that the parent difuran making possible sequential Diels-Alder reactions with different dienophiles. Reaction with a tethered bis(dienophile) leads to the production of a naphthalenic cyclophane.     

Kinetics of phase changes in large molecular clusters

A method has been devised to study the kinetics of phase changes in an unfamiliar regime of extreme undercooling and rate of transformation. We show how electron diffraction can monitor the time evolution of phase changes in molecular clusters condensed from the vapor in supersonic flow. Transitions taking place in microseconds are readily followed. Examples include solid state transformations as well as the freezing of liquid clusters. Aspects of the experiment making it possible to observe familiar transitions under highly unusual conditions will be discussed along with some advantages of the new technique.     

On the nature of pulsars

The paper contains a relatively non-technical summary of some recent work by the author and Jeremy Butterfield. The goal is to find a way of assigning meaningful truth values to propositions in quantum theory: something that is not possible in the normal, instrumentalist interpretation. The key mathematical tool is presheaf theory where multi-valued, contextual truth values arise naturally. We show how this can be applied to quantum theory, with the ‘contexts’ chosen to be Boolean subalgebras of the set of all projection operators.     

Direct kinetic studies of the reactions of 2-butoxy radicals with NO and O2

This Letter reports the first kinetic study of 2-butoxy radicals to employ direct monitoring of the radical. The reactions of 2-butoxy with O₂ and NO are investigated using laser-induced fluorescence (LIF). The Arrhenius expressions for the reactions of 2-butoxy with NO (k₁) and O₂ (k₂) in the temperature range 223–311 K have been determined to be k₁=(7.50±1.69)×10⁻¹²×exp((2.98±0.47) kJmol⁻¹/RT) cm³ molecule⁻¹ s⁻¹ and k₂=(1.33±0.43)×10⁻¹⁵×exp((5.48±0.69) kJmol⁻¹/RT) cm³ molecule⁻¹ s⁻¹. No pressure dependence was found for the rate constants of the reaction of 2-butoxy with NO at 223 K between 50 and 175 Torr.     

Electron impact mass spectra of isobenzofurans,isonaphthofurans and some of their Diels–Alder adducts

The mass spectra of a wide variety of substituted isobenzofurans (IBF) have been studied by the direct examination of stable IBFs and IBF ions formed in the retro-Diels–Alder cleavage of oxabicyclo adducts. In general, the fragmentation patterns observed are very dependent upon the nature and position of substitution. The dimethyl acetylenedkarboxylate adducts also show additional interesting and novel fragmentation pathways that are not IBF related.