Tarkeshwar Gupta

Self-Propagating Assembly of a Molecular-Based Multilayer

Accelerated growth of a molecular-based material that is an active participant in its continuing self-propagated assembly has been demonstrated. This nonlinear growth process involves diffusion of palladium into a network consisting of metal-based chromophores linked via palladium.

Selective monitoring of parts per million levels of CO by covalently immobilized metal complexes on glass

Optical detection of parts-per-million (ppm) levels of CO by a structurally well-defined monolayer consisting of bimetallic rhodium complexes on glass substrates has been demonstrated.

Selective Optical Recognition and Quantification of Parts Per Million Levels of Cr6+ in Aqueous and Organic Media by Immobilized Polypyridyl Complexes on Glass

Selective optical sensing of parts per million levels of Cr(6+) in water under acidic conditions with robust, osmium-chromophore-based monolayers is demonstrated. The sensor system can be reset by washing with water at neutral pH and can be readily monitored by UV/vis spectroscopy.

A Monolayer-Based Setup for Optical Amplification

Signal amplification has been demonstrated with surface-bound electrochromic complexes that can exist in one of two oxidation states (M2+/3+). Reaction of FeCl3 with covalently immobilized Os2+ complexes on glass substrates converts the metal centers from one oxidation state to the other. The formed Fe2+ reduces a series of Ru3+-based monolayers. The absorption of light is coupled with the oxidation state of the complexes and provides the output for the monolayer-based device. The gain of the setup can be controlled by the addition of a Fe2+ chelating ligand.

Selective NOx optical sensing with surface-confined osmium polypyridyl complexes

Optical detection of parts-per-million (ppm) levels of NO2 (1-10 ppm) and NO(x) (800-2550 ppm) by a structurally well-defined monolayer consisting of osmium polypyridyl complexes on glass substrates has been demonstrated.