Synthesis, stability, and antimicrobial studies of electronically tuned silver acetate N-heterocyclic carbenes.

A series of methylated imidazolium salts with varying substituents on the 4 and 5 positions of the imidazole ring were synthesized. These salts were reacted with silver acetate to afford their corresponding silver N-heterocyclic carbene (NHC) complexes. These complexes were then evaluated for their stability in water as well as for their antimicrobial efficacy against a variety of bacterial strains associated with cystic fibrosis and chronic lung infections.

Synthesis from caffeine of a mixed N-heterocyclic carbene-silver acetate complex active against resistant respiratory pathogens.

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 4 was accomplished by the in-situ deprotonation of 1 by silver acetate in methanol. Complex 4 demonstrated antimicrobial activity against numerous resistant respiratory pathogens from the lungs of cystic fibrosis (CF) patients including members of the Burkholderia cepacia complex 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.

Design, characterization, and X-ray structure of an interlocked dinuclear chair-like metallomacrocycle: [Fe(II)2(3,5-bis(2,2':6',2''-terpyridin-4'-phen-3-yl)toluene)2][4PF6-].

The self-assembly of 3,5-bis(2,2':6',2''-terpyridin-4'-phen-3-yl)toluene with an equimolar amount of a Fe(II) salt afforded a high yield of an interlocked dinuclear tetracationic "molecular gear" that was confirmed by single crystal X-ray data.

Synthesis and single-crystal X-ray characterization of 4,4"-functionalized 4'-(4-bromophenyl)-2,2':6',2"-terpyridines.

To expand the utility of bis(terpyridine) metal connectivity, the selective symmetrical and unsymmetrical 4,4"-functionalization (-CN, -Me, -CO2Me) of 4'-(4-bromophenyl)-2,2':6',2"-terpyridines was achieved using the Kröhnke synthesis. The final substituted 2,2':6',2"-terpyridines along with their corresponding intermediates, 4a-c, were recrystallized and characterized by 1H NMR and 13C NMR as well as X-ray crystallography; COSY correlations were also conducted to permit definitive proton assignment.

Layer architecture in 4-nitrophenyl and 4-chlorophenyl 3-nitrobenzenesulfonate at 100 K.

The structures of the title compounds, C(12)H(8)N(2)O(7)S and C(12)H(8)ClNO(5)S, contain weak C-H.O interactions creating layers of molecules which, taking the conformation of the molecules into account, are arranged in an ABAB sequence. Both structures can be designated, therefore, as ordered racemates of rotameric species.

2-Chlorophenyl 3-nitrobenzenesulfonate and 2,4-dichlorophenyl 3-nitrobenzenesulfonate: supramolecular aggregation through C-H...O, pi-pi and van der Waals interactions.

In 2-chlorophenyl 3-nitrobenzenesulfonate, C(12)H(8)ClNO(5)S, and 2,4-dichlorophenyl 3-nitrobenzenesulfonate, C(12)H(7)Cl(2)NO(5)S, weak C-H...O interactions generate S(5), S(6) and R(2)(2)(7) rings. The supramolecular aggregation is completed by the presence of pi-pi interactions and intermolecular van der Waals short contacts.