Basireddy V. Subba Reddy

Recent Advances in Dye Sensitized Solar Cells

Solar energy is an abundant and accessible source of renewable energy available on earth, and many types of photovoltaic (PV) devices like organic, inorganic, and hybrid cells have been developed to harness the energy. PV cells directly convert solar radiation into electricity without affecting the environment. Although silicon based solar cells (inorganic cells) are widely used because of their high efficiency, they are rigid and manufacturing costs are high. Researchers have focused on organic solar cells to overcome these disadvantages. DSSCs comprise a sensitized semiconductor (photoelectrode) and a catalytic electrode (counter electrode) with an electrolyte sandwiched between them and their efficiency depends on many factors. The maximum electrical conversion efficiency of DSSCs attained so far is 11.1%, which is still low for commercial applications. This review examines the working principle, factors affecting the efficiency, and key challenges facing DSSCs.

Ionic liquid/water mixture promoted organic transformations

Ionic liquids (ILs) have been used in numerous applications in chemistry. Wet ILs constitute a new class of solvents with their own new and interesting properties. The properties of ILs are significantly influenced by the addition of water and also affect reaction rates and selectivity. IL/water mixing makes it easy to control the properties of the solution and the formation of these ionic liquid mixtures increases synthetic flexibility. In this review, mixtures of IL/water solvent system promoted organic reactions have been described and the results are compared with other solvent systems. In many cases IL/water combinations were superior compared to conventional organic solvents and biphasic IL/organic co-solvent media with respect to catalytic performance as well as to catalyst separation and recycling.

Synthesis, molecular docking and in vitro antiproliferative activity of novel pyrano[3,2-c]carbazole derivatives

A new series of polycyclic pyrano[3,2-c]carbazole derivatives have been synthesized by domino Knoevenagel–hetero-Diels–Alder reactions. The key strategy involves ethylenediamine diacetate (EDDA) catalyzed cyclization of the O-prenyl derivative of N-Boc-carbazole-3-carboxaldehyde with cyclic 1,3-diketones or pyrazol-5-ones to afford cis-fused N-Boc-pyrano[3,2-c]carbazole derivatives. The reactions were clean and highly diastereoselective, affording the desired products in good yields. The deprotection of the Boc group under acidic conditions led to pyrano[3,2-c]carbazole derivatives. The antiproliferative activity of all the synthesized compounds on three cancer cell lines such as PANC 1 (pancreatic), HeLa (cervical) and MDA-MB-231 (breast cancer) was investigated. The results clearly demonstrated that compounds 12d, 12f and 12g displayed pronounced antiproliferative activity. In addition, the antimicrobial activity of these compounds was also assayed against three representative Gram-positive organisms and Gram-negative organisms. Specifically, compound 12d exhibited significant antimicrobial activity. Molecular docking studies revealed that the lead compounds selectively occupy the colchicine binding site of tubulin.