Strained thiacyclophanes: Reducing properties and gauge of transannular interactions.

The current study involves the investigation of reducing properties of disulfide bonded heteraphanes. The calculated adiabatic electron affinity (AEA) values of heteraphanes are found comparable to that of cystine molecule and are capable of undergoing reversible redox reactions. In aqueous phase, these show high propensity to get reduced. The reaction energies calculated using isodesmic equations reflect the strain associated with the studied thiacyclophane models. Increase in the number of disulfide bonds results in less strain and more stabilization. Through-space transannular interactions in the selected heteraphanes have a decisive influence on the structure stabilization associated with the systems. The results reported in the current study are expected to play a vital role while designing redox driven drug carriers by incorporating these systems in biomolecules.

Mixed monolayer protected gold atom-oxide cluster synthesis and characterization.

Small atomic gold clusters in solution, Au(n), stabilized by cetyl trimethylammonium bromide (CTAB) and cysteine, have been synthesized potentiodynamically in quiescent aqueous solutions. The electrodissolution of gold to gold ions during an anodic scan and subsequent cluster formation during a cathodic scan in underpotential (UPDD) and overpotential dissolution-deposition (OPDD) regions were studied. The experimental potentiodynamic I-E profiles and chronoamperometric i-t transients are fit into reported theoretical models of adsorption and electrocrystallization. The plausible application of clusters/cluster film to cysteine sensing based on fluorescence quenching and square wave stripping voltammetry is demonstrated.