8 research outputs found
An unexpected stereochemical course of dihydroimidazolium ylide cycloadditions
An unexpected stereochemical course of dihydroimidazolium ylide cycloaddition
Two Cu(II) complexes from an N-alkylated benzimidazole: synthesis, structural characterization, and biological properties
<div><p>Two mononuclear copper(II) complexes, [Cu(L)Cl<sub>2</sub>](CH<sub>3</sub>OH)<sub>2</sub> and [Cu(L)(NO<sub>3</sub>)<sub>2</sub>], were prepared and characterized by spectroscopic and analytic methods, where L is 2,6-bis(1-butyl-1<i>H</i>-benzo[<i>d</i>]imidazol-2-yl)pyridine. Molecular structures of the complexes were determined by X-ray diffraction. The X-ray data revealed that the complexes are mononuclear and coordination geometry around Cu(II) is distorted square pyramidal. The complexes were screened for their <i>in vitro</i> antibacterial and antifungal activities. The complexes show moderate antifungal activities against <i>Saccharomyces cerevisiae</i>, <i>Candida utilis,</i> and <i>Candida albicans</i>. Moreover, the complexes inhibit the development of <i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i>.</p></div
Double template effect in [4+4] Schiff base macrocycle formation: an ESI-MS study
The mechanism of self-assembly of a polynuclear complex
of a [4 + 4] Schiff base iminomethylenediphenolate macrocycle
[BaCu4(4 + 4)]2+ via a non-macrocyclic dialdehyde intermediate
has been followed using ESI-MS of the reaction
solutions. Both assembly of the intermediate and Schiffbase
condensation with diamine give rise to single products;
formation of the intermediate metallacycle is fast but Schiffbase
condensation ismuch slower. Both intermediate complex
andmacrocyclic product have been structurally characterised
A novel trisprotonated beta-dialdiminate cryptand
A novel trisprotonated beta-dialdiminate cryptan
Nanostructured alpha-Fe2O3 thin films for photoelectrochemical hydrogen generation
We acknowledge PMI2 connect program
of the British Council for partly funding the present
work
Amides as precursors of imidoyl radicals in cyclisation reactions
Amides have been successfully used as precursors of imidoyl radicals for radical cyclisation. The amides have been converted to imidoyl selanides via reaction with phosgene to yield imidoyl chlorides followed by reaction with potassium phenylselanide. Imidoyl selanides were reacted with tributyltin hydride (Bu3SnH) as the radical mediator with triethylborane or AIBN as initiators to yield imidoyl radicals for cyclisation reactions. Imidoyl radicals have been cyclised onto alkenes to yield 2,3-substituted-indoles and -quinolines and also onto pyrroles and indoles to give bi- and tricyclic heteroarenes
Silver(I) complexes of 9-anthracenecarboxylic acid and imidazoles: synthesis, structure and antimicrobial activity
[Ag2(9-aca)2] (1) (9-acaH = 9-anthracenecarboxylic acid) reacts with a series of imidazoles to give
[Ag(imidH)2.3(CH3CN)0.7](9-aca) (3), [Ag6(imidH)4(9-aca)6(MeOH)2] (4), {[Ag(1-Me-imid)2]2[Ag4(9-
aca)6]} (5), {[Ag(1-Bu-imid)2]2[Ag4(9-aca)6]} (6) and [Ag(apim)](9-aca)·H2O (7) (imidH = imidazole;
1-Me-imid = 1-methylimidazole; 1-Bu-imid = 1-butylimidazole; apim = 1-(3-aminopropyl)imidazole).
The mononuclear complex 3, hexanuclear 4–6, and polymeric 7, were all characterised using X-ray
crystallography. While many of the complexes possess excellent in vitro antifungal and antibacterial
activities they are, unanimously, more effective against fungal cells. The insect, Galleria mellonella, can
survive high doses of the Ag(I) complexes administered in vivo, and a number of the complexes offer
significant protection to larvae infected with a lethal dose of pathogenic Candida albicans cells
Regulating Bioactivity of Cu<sup>2+</sup> Bis-1,10-phenanthroline Artificial Metallonucleases with Sterically Functionalized Pendant Carboxylates
The
synthetic chemical nuclease, [Cu(1,10-phenanthroline)<sub>2</sub>]<sup>2+</sup>, has stimulated research within metallonuclease development
and in the area of cytotoxic metallodrug design. Our analysis reveals,
however, that this agent is “promiscuous” as it binds
both dsDNA and protein biomolecules, without specificity, and induces
general toxicity to a diversity of cell lineages. Here, we describe
the synthesis and characterization of small-molecule metallonucleases
containing the redox-active cation, [Cu(RCOO)(1,10-phen)<sub>2</sub>]<sup>+</sup>, where 1,10-phen = 1,10-phenanthroline and R = −H,
−CH<sub>3</sub>, −C<sub>2</sub>H<sub>5</sub>, −CH(CH<sub>3</sub>)<sub>2</sub>, and −C(CH<sub>3</sub>)<sub>3</sub>.
The presence of coordinated carboxylate groups in the complex cation
functions to enhance dsDNA recognition, reduce serum albumin binding,
and offer control of toxicity toward human cancer cells, Gram positive
and negative bacteria, and fungal pathogens. The induction of genomic
dsDNA breaks (DSBs) were identified in ovarian adenocarcinoma cells
using immunodetection of γ-H2AX. Formate, acetate, and pivalate
functionalized complexes induced DSBs in a higher percentage of cells
compared with [Cu(1,10-phen)<sub>2</sub>]<sup>2+</sup>, which supports
the importance of inner-sphere modification toward enhancing targeted
biological application