An efficient catalytic system for cyclocarbonylation of terpenes into lactones

Three different kinds of representative monoterpenic alcohol are involved in the palladium‐catalysed cyclocarbonylation reaction. Lactone formation is shown to occur when cyclic ( 1 ), tertiary ( 3 ) and primary allylic alcohol ( 7 ) functions are reacted, in the presence of CO with [HPd(SnCl₃)L₂] as the active catalytic species. Good yields and selectivities can easily be reached for isopulegol ( 1 ), and dihydromyrcenol ( 3 ). However, more modest results are obtained for the functionalization of geraniol into the original lactone ( 9 ). This lactone can be largely favoured by using a basic chelating diphosphine ligand such as 1,4‐bis(diphenylphosphino)butane. Copyright © 2005 John Wiley & Sons, Ltd.     

Fixed point of multivalued mapping in uniform spaces

In this paper we prove some new fixed point theorems for multivalued mappings on orbitally complete uniform spaces.     

A note on forced vibrations of a clamped rectangular plate

Simple polynomial approximations and Galerkin's method are used to determine the response of a thin, elastic, rectangular plate clamped along the boundary and subjected to sinusoidal excitation. It also is shown that a one-term polynomial solution yields good accuracy in the case of a rectangular plate with simply supported edges.     

Nouvelle synthese de precurseurs phenoliques des lignines utilisant les sels d'iminium des acides p-hydroxy cinnamiques

4-Hydroxy cinnamic esters, thiolesters, aldehydes and alcohols, or related compounds, implied in the biosynthesis of lignins are easily synthesized in good yields from iminium salts of coumaric $\text{1a}$, ferulic $\text{1b}$ and sinapic $\text{1c}$ acids. No prior protection of the phenol group is needed in this method.     

Molecular recognition in structured matrixes: control of guest localization in block copolymer films

We demonstrate the use of molecular recognition to control the spatial distribution of guest molecules within block copolymer films. Block copolymers bearing recognition units were combined with complementary and noncomplementary molecules, and the extent of segregation of these molecules into the different domain types within microphase-separated thin films was quantitatively analyzed using dynamic secondary ion mass spectrometry (SIMS). Complementarity between the guest molecules and the polymer functionalities proved to be a key factor and an efficient tool for directing the segregation preference of the molecules to the different domain types. The effect of segregation preference on the glass transition temperature was studied using differential scanning calorimetry (DSC), and the results corroborate the SIMS findings. In a complementary study, guests with tunable sizes (via dendron substituents) were used to control block copolymer morphology. Morphological characterization using transmission electron microscopy (TEM) and X-ray diffraction reveal that selectivity differences can be directly translated into the ability to obtain different morphologies from recognition unit-functionalized block copolymer scaffolds.     

Duplex strand formation using alternating copolymers

The regular arrangement of complementary diaminopyridine-thymine (DAP-THY) on alternating copolymers permits cooperative binding events and the effective formation of well-controlled micrometre-scale aggregates.     

Some low-modulus birefringent resins

Information is given to enable the photoelastician to select and prepare his own clear, bubblefree, constant-thickness, low-modulus (500 psi or less) birefringent resins. Various urethane formulations are examined. The effects of environment, mixing, casting, molds, cure, post-cure and calibration are discussed. A procedure to select a particular formulation is suggested.     

Levels of cesium radionuclides in mosses in the eastern Black Sea area of Turkey

Moss samples collected from the eastern Black Sea about 6.5 years after the Chernobyl accident have been analyzed for radiocesium activity.¹³⁴Cs activity was also detected in all the samples beside¹³⁷Cs radionuclide. The levels of total cesium activity in the mosses proved that the coastal zone in the eastern Black Sea region was highly contaminated.