A simple two-steps process was employed. The second step involves the closure of the capsule by coordination of the bottom and top part to Pd II and Pt II centers. This process takes place on bulk substrates, on microcontact printed substrates, as well as on single molecules. Analysis of the crystal structure and NMR profiles suggested a charge-transfer interaction between the host and guest as well as the presence of van der Waals interactions in the inclusion complexes. Their characterization by spectroscopic methods is reported.
Cyclopropane formation is observed with styrene.
The structural features and reactivity patterns of the novel copper carbenes are consistent with their description as Fischer carbenes and support the mechanistic picture proposed for copper-catalyzed stereoselective cyclopropanations. These complexes are anticipated to undergo deprotonolysis in the presence of bases to yield anionic phosphine-containing complexes which facilitate the oxidative addition of aryl chlorides in the catalytic cycles. The molecular origin of the anticoagulant and antithrombotic activities of heparin is the presence in its polymeric chain of a defined pentasaccharide sequence. A key component of this active site is L-iduronic acid, a peculiar monosaccharide endowed with remarkable conformational flexibility. All rights reserved.