A series of water soluble Keggin type heteropolyoxotungstates have been tested as oxidation catalysts in aqueous-biphasic media with dilute H₂O₂ (30%) as the oxygen atom donor, without using any phase transfer agent. The Zn substituted polyoxoanion {(NH₄)₇Zn_0.5[𝛼-ZnO₄W₁₁O₃₀ZnO₅(OH₂)]$.n$H₂O} has been found to be the most efficient catalyst, which oxidizes a wide range of organic functionalities with good turnovers and high selectivities. The functionalities that undergo oxidations are: organic sulfides, pyridines, anilines, benzyl alcohols and benzyl halides. The oxidations of sulfides to sulfoxides and/or sulfones have been studied in detail, and a simple kinetic model consisting of two consecutive reactions, is shown to give good fit with the experimental data. In the catalytic system described here product isolation is easy, and the aqueous catalyst solution can be re-used several times with little loss in its efficiency.

9-Ethynylphenanthrene (EPT) bound to highly monodispersed Ruthenium (Ru) nanocluster (Ru:EPT) with mean diameter of 1.5 ± 0.2 nm and mol wt. of ~8600 Da was synthesized via a facile and high yield biphasic ligand exchange protocol using similar sized ethylene glycol (EG)-stabilized Ru clusters (Ru:EG) as precursor. The synthesized organometallic nanocluster was meticulously analyzed to understand its size distribution, oxidation state, crystallinity, optical and luminescence behavior and metal–ligand interfacial structure. Contrary to the extensive quenching of ligand emission by metalcore as usually observed, the ruthenium core here acts as a conductor, which conjugates surface ligands with strong emission property courtesy to an unusual vinylidene-binding motif. Thus, the synthesized nanocluster shows good luminescence property (φ= ~7%) originated from the ligand skeleton and the spherical metal core restricts lateral overlap of phenanthrene moiety to cause any excimer emission. This nanocluster showed high sensitivity for solution phase detection of nitroaromatic explosives through luminescence quenching method (KSVup to 498×10.⁴M ^-1) andmimic the mechanism like conjugated organic polymer. We propose that dynamic χ−χ interaction between Ru bound phenanthrene moiety and nitroaromatic compounds followed by photoinduced electron transfer (PET), as well as Förster Resonance Energy Transfer (FRET), are the possible mechanisms behind this luminescence quenching.