The present work describes ultrafast thermalized and hot hole transfer processes from photo-excited CdSe quantum dots (QDs) and CdSe/ZnS core-shell QDs (CSQDs) to newly synthesized thiols. Three thiols namely 2-mercapto-N-phenylacetamide (AAT), 3-mercapto-N-phenylpropanamide (APT) and 3-mercapto-N-(4-methoxyphenyl) propanamide (ADPT) were synthesized and their interaction with both CdSe QDs and CdSe/ZnS CSQDs was monitored. Steady state absorption study suggests the exciton delocalization from CdSe QDs in the presence of the thiols. However similar features were not observed in the presence of a ZnS shell over a CdSe core, instead a broadening in the excitonic peak was observed with both APT and ADPT but not with AAT. This exciton delocalization and broadening in the excitonic peak was also confirmed by ultrafast transient absorption studies. Steady state and time resolved emission studies show hole transfer from photo-excited QDs and CSQDs to the thiols. A signature of hot hole extraction was observed in transient absorption studies which was confirmed by fluorescence upconversion studies. Both hot and thermalized hole transfer rates from CdSe QDs and CdSe/ZnS CSQDs to the thiols were determined using the fluorescence up-conversion technique. Experiments with different ZnS shell thicknesses have been carried out which suggest that hole transfer is possible till 2.5 monolayer of the ZnS shell. To the best of our knowledge we are reporting for the first time the extraction of hot holes from CdSe/ZnS type I CSQDs by a molecular adsorbate.

The mildly acidic and oxidative nature of graphene oxide, with its large surface area available for catalytic activity, has been explored in aromatic nuclear bromination chemistry for the first time. The versatile catalytic activity of graphene oxide (GO) has been used to selectively and rapidly brominate anilines and phenols in water. The best results were obtained at ambient temperatures using molecular bromine in a protocol promoted by oxidative bromination catalyzed by GO; these transformations proceeded with 100% atom economy with respect to bromine and high selectivities for the tribromoanilines and -phenols. Reduced graphene oxide (r-GO) was observed to form after the second recycle (third use) of GO. This technique is also effective with N-bromosuccinimide (NBS) as the brominating reagent. In the case of NBS, reactions were instantaneous and the GO displayed excellent recyclability without any loss of activity over several cycles.

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Biodegradable and economically viable choline chloride-FeCl 2. H 2 O deep eutectic solvent (DES), was synthesized and successfully utilized as a catalyst and reaction medium for the selective oxidation of aromatic methyl groups to aldehydes. To demonstrate the synthetic potential of this protocol, the reaction was scaled up to the gram scale. The DES could be reused up to four times without considerable effect on the yield of the reaction. The key features of the protocol that qualify the process as green include the ambient reaction temperatures, easy isolation of the products, higher yields, recyclability of the catalyst, and reactions without the use of conventional organic solvents.

We prepared a commercially viable Deep Eutectic Solvent (DES) based on Choline Chloride‐Urea‐copper acetate for the first time. It mediates the homocoupling of terminal alkynes, using air as an oxidant. Water is the only by‐product of the entire process. The method avoids ligands, bases, oxidants, and costly palladium catalysts, which qualifies the process greener than ever. The DES can be reused at least three times without affecting the reaction yield significantly. The key features of the protocol that qualify the process as green include the ambient reaction temperatures, lesser use of conventional organic solvents in the reaction, higher yields, and easy product isolation qualify the protocol as a green process.