Unprecedented ring-enlargements to four-membered rings by 3+1 -cycloadditions employing isonitriles, carbenes
and nitrenes are envisioned, aryne insertions into the three-membered ring leading to indane systems are planned and a general concept for 3+3 -cycloadditions with 1,3-dipoles is presented paving the way to unusual syntheses of heterocycles.
Queen's University chemistry professor Cathleen Crudden admits that neither she nor her Department of Chemistry colleague Hugh Horton had any commercial applications in mind when they began their work into the reaction of carbon-based ligands called carbenes
with metal surfaces.
They made a series of seven new compounds, called caffeine-based gold (I) N-heterocyclic carbenes
, in the laboratory and studied them.
The latter chapters cover lithium, rhodium, ruthenium, chromium, cobalt, and gold in interaction with carbenes
Diazo-compounds are known to yield carbenes
by heating, catalytic decomposition or ultraviolet (UV) irradiation (23), (24).
FLUORESCENT RHODIUM AND IRIDIUM COMPLEXES DERIVED FROM N-HETEROCYCLIC CARBENES
It consists of six chapters covering heavy analogs of: carbenium, free radicals, carboanions, carbenes
, unsaturated hydrocarbons, and aromatic compounds.
The imidazolium cation has been the focus of much attention in recent years, most notably as a source of N-heterocyclic carbenes
, which can be used either as ligands for transition metal catalysts or as catalysts themselves, and as the cationic component of the most popular family of room temperature ionic liquids.
9:15 GRUBBS-TYPE METATHESIS CATALYSTS WITH FUNCTIONALIZED CARBENES
In an advance that could lead to new catalysts for chemical reactions, scientists in Europe have found a novel way to stabilize highly reactive molecules called carbenes
However, despite these significant achievements, the scope of catalytic nitrene transfers remains mainly confined to these two reactions, and, thus, limited when compared to the chemistry of carbenes
, typically cyclic, usually contain a carbon with a lone pair of electrons and have a nitrogen-carbon-nitrogen organization at the active site, hence the distinction N-heterocyclic carbene