Manoj Warrier

Photocatalytic reduction of aromatic azides to amines using CdS and CdSe nanoparticlesElectronic supplementary information (ESI) available: The preparation of CdS and CdSe nanoparticles, the synthesis of aromatic azides, procedures for the photocatalyzed reduction of aromatic azides, and procedures for the quantum yield measurements. See http://www.rsc.org/suppdata/pp/b4/b404268a/

We have shown that CdS and CdSe nanoparticles can act as very efficient and highly chemoselective photocatalysts for the reduction of aromatic azides to aromatic amines. In several cases, the reaction proceeds with quantum yields near 0.5, which approaches the theoretical maximum for a two-electron process. The wide scope of the reaction was confirmed with compounds containing electron withdrawing (-NO(2), CO(2)R, COR) and electron donating groups (-OMe, -R, -Cl) at the para-, meta-, and ortho-positions. Remarkably, the reaction is relatively insensitive to the electron demands of the substituent. However, azides with meta-substituents give slightly lower yields than those with the same substituent at the ortho- or para-position.

Photo-fries reaction of naphthyl esters within zeolites

Abstract Photolysis of naphthyl esters within zeolites leads to the photo-Fries rearrangements as in isotropic solution. However, a high level of product selectivity is obtained using ‘cation as the key’. A key component for predicting the selectivity of photoreactions within zeolites, namely the location of reactants, is missing at this stage.

Heavy cation effect on intersystem crossing between triplet and singlet phenylacyl and benzyl geminate radical pairs within zeolites

The difference in product selectivity observed between dibenzyl ketones and naphthyl esters in zeolites is due to the difference in spin of the radical pairs formed from these precursors. Heavy cations present in zeolites can enhance intersystem crossing between triplet and singlet geminate radical pairs.

Novel approaches towards the generation of excited triplets of organic guest molecules with zeolites

Alkali metal cation-exchanged zeolites (M+X or M+Y) can be used as ‘microreactors’ in which to carry out photochemical rearrangement reactions of organic guests.