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The bis(N-heterocyclic carbene) (NHC) silver complex, 3, with a methyl carbonate anion was formed from the reaction of the iodide salt of methylated caffeine, 1, with silver (I) oxide in methanol. Attempts to crystallize this complex from a mixture of common alcohols and ethyl acetate led to the formation of an NHC-silver acetate complex, 4. The more direct synthesis of 4was accomplished by the in-situ deprotonation of 1 by silver acetate in methanol. Complex 4demonstrated antimicrobial activity against numerous resistant respiratory pathogens from the lungs of cystic fibrosis (CF) patients including members of the Burkholderia cepaciacomplex that cause a high rate of mortality in patients with cystic fibrosis (CF). Application of this NHC silver complex to primary cultures of murine respiratory epithelial cells followed by microarray analysis showed minimal gene expression changes at the concentrations effective against respiratory pathogens. Furthermore, methylated caffeine without silver showed some antibacterial and antifungal activity.

A new chiral aziridino alcohol ligand for zinc(II)-catalyzed azomethine ylide cycloadditions is described. In the presence of this catalyst, N-arylidene glycine methyl esters react with a variety of dipolarophiles to give substituted pyrrolidines in very good to excellent chemical yields and up to 95% ee. The absolute sense of asymmetric induction appears to be dipolarophile-dependent.

Highly functionalized pyrrolidines are obtained in a single chemical step via a mild, efficient, and selective AgI-catalyzed asymmetric CNCCC coupling process. Oppolzer's camphorsultam enables the desired reaction cascade and provides a reliable means to control the developing stereochemistry and purify the products. This three-component reaction provides unprecedented access to structurally diverse pyrrolidines for both target- and diversity-oriented syntheses.

Hexacoordinate silicon bis chelates with the SiC2O2N2 ligand framework have been prepared, with different nitrogen-donor ligands, NMe2 and N&dbd;CMe2. Crystal diffraction analyses revealed that the former type had a bicapped-tetrahedral geometry and the latter an octahedral molecular geometry in the solid state. The two N→Si dative bonds in the isopropylideneimino-coordinated compound are sufficiently strong to change silicon from its tetrahedral ground-state configuration to the higher energy octahedral configuration. In contrast, the weaker NMe2 donor groups do not form strong enough bonds to cause this change, and as a result silicon remains tetrahedral and forms only substantially longer and weaker N→Si dative bonds (2.7−2.8 Å). Remote electron-releasing NMe2 substituents on the chelate rings render the ligand NMe2 groups stronger donors, resulting in reversal of the solid-state geometry back to octahedral. 29Si, 1H, and 13C NMR spectra at various temperatures provide evidence for the coexistence in equilibrium of the bicapped-tetrahedral and octahedral geometries in solution, with the octahedral to tetrahedral population ratio increasing as the temperature is decreased.