Search

Research has been conducted on spirobenzopyrans which bear monoazathiacrown ethers and noncyclic analogues. The synthesis of these spirobenzopyrans has been carried out and their ion-responsive photochromism has been investigated via the use of alkali and alkaline-earth metal ions.

The design and synthesis of a novel phosphodiester receptor 1-(2-guanidinoethyl)-4-(2-hdyroxyethyl)1-1,4,7-triazacyclononane hydrochloride and the studies of its DNA cleavage activity is reported. Kinetic data of DNA cleavage promoted by 1-(2-guanidinoethyl)-4-(2-hdyroxyethyl)1-1,4,7-triazacyclononane hydrochloride fit to a Michaelis-Menten-type equation with [K.sub.max] of 0.160 [h.sup.-1] giving [10.sup.7]-fold rate acceleration over uncatalyzed DNA.

The first example of the homoleptic, dinuclear, cationic metal carbonyl catalyst in concentrated sulfuric acid, with which olefins react with CO to produce tertiary carboxylic acids in high yields at atmospheric pressure and room temperature, is reported. It was observed that the cis-Pt-(CO)2 square+9solv) has a very low catalytic activity for the carbonylation of olefins in strong acids.

A novel efficient approach to optically pure bridging chiral calix[4]arenes through a homologous anionic ortho-Fries rearrangement of inherently chiral calix[4]arenes was presented for the first time. As a result, two pairs of N,N′-dimethylformamidyl-substituted bridging chiral p-tert-butylcalix[4]arene enantiomers were facilely obtained. Their absolute configurations were determined through ROESY analysis, ECD comparison, and X-ray crystallographic analysis. [ABSTRACT FROM AUTHOR]

Reports on a facile route for the preparation of the rhodium(I) tetracarbonyl cation, [Rh(CO)4]+, from the neutral Rh carbonyl cluster, Rh4(CO)12, in concentrated H2SO4 solution under a CO atmosphere. First example of the oxidation of Rh(0) to Rh(I) by H+; Action of the Rh(I) tetracarbonyl cation to catalyze the carbonylation of the olefins.

Studies the palladium catalyst exhibiting catalytic activity for carbonylation of olefins and alcohols. Palladium(I) carbonyl cation in concentrated H2SO4; Complex changes of terminal CO ligands and its role in carbonylation of olefins and alcohols; Catalytic behavior of palladium carbonyl; Reaction of olefins and alcohols to strong acids.

Examines the hexacarbonyldiplatinum(I) cation-catalyzed carbonylation of olefins in concentrated sulfuric acid. Formation of carbocation intermediate; Protonation of the isomerized olefins; Effects of cationic metal carbonyl catalyst on the carbonylation rate; Characterization of the platinum-carbon bonding.