University of Hyderabad

About: University of Hyderabad is a education organization based out in Hyderabad, India. It is known for research contribution in the topics: Catalysis & Crystal structure. The organization has 6446 authors who have published 13005 publications receiving 237641 citations. The organization is also known as: Hyderabad Central University & HCU.

Sterically demanding zinc(II) phthalocyanines: synthesis, optical, electrochemical, nonlinear optical, excited state dynamics studies

Abstract: Two novel sterically demanding zinc phthalocyanines were synthesized and characterized Their optical and electrochemical properties were investigated in detail The emission spectra were recorded in different solvents and the fluorescence yields obtained were in the range of 02–03 while time-resolved fluorescence data revealed radiative lifetimes of typically few ns Nonlinear optical (NLO) properties were also evaluated at wavelengths of 600, 640, 680, and 800 nm using picosecond (∼15 ps) pulses and further studies with femtosecond (∼140 fs) pulses at 800 and 780 nm were also performed Two-photon absorption (2PA) and saturable absorption (SA) were the dominant nonlinear absorption mechanisms observed with ps/fs excitation at different wavelengths in the visible spectral region NLO coefficients were extracted from ps/fs closed and open aperture Z-scan measurements Large two-photon absorption cross-sections of ∼14 000 GM and n2 values in the range of 1–7 × 10−16 cm2 W−1 were retrieved for these molecules from the ps Z-scan data The excited state decay dynamics were investigated using degenerate pump-probe experiments with ∼70 fs pulses near 600 nm Double exponential fits of the pump-probe data suggested two decay times for both molecules investigated

Structure and microstructure of combustion synthesized MgO nanoparticles and nanocrystalline MgO thin films synthesized by solution growth route

Abstract: In this work we describe the synthesis, micro structure (XRD, SEM, AFM) of magnesium oxide nanoparticles and magnesium oxide thin films synthesized by urea-based combustion method and solution growth route using magnesium nitrate as the source of Mg We used fuel-to-oxidizer ratio (Ψ) as a control parameter to investigate how lattice parameter, particle size, and micro strain vary with Ψ = 025–2 in the steps of 025 Earlier we have studied NiO as a substitutional solute in MgO (Rao KV, Sunandana (2005) Solid State Phys 50:235) The average crystalline size of MgO was estimated from the full width half maximum (Gaussian and lorentzian fits) of the X-ray diffraction peaks using Sherrer’s formula and Williamson–Hall plot The particle size varies from 15(±03) nm to 60(±12) nm as Ψ is varied systematically Surface areas of the MgO powders measured using BET method were used to calculate the particle size, which is comparable with the crystalline size calculated from XRD We also calculated porosity and microstrain in the MgO nanoparticles with varying Ψ Thin films of MgO are well characterized from XRD and AFM The size of the particles and RMS roughness of the thin films were calculated using AFM

Umpolung Reactivity of Ynamides: An Unconventional [1,3]-Sulfonyl and [1,5]-Sulfinyl Migration Cascade.

Abstract: A regioselective sulfonyl/sulfinyl migration cycloisomerization cascade of alkyne-tethered ynamides is developed in the presence of XPhosgold catalyst. This reaction is the first example of a general [1,3]-sulfonyl migration from the nitrogen center to the β-carbon atom of ynamides, followed by umpolung 5-endo-dig cyclization of the ynamide α-carbon atom to the gold-activated alkyne, and final deaurative [1,5]-sulfinylation. This process allows the synthesis of peripherally decorated unconventional 4-sulfinylated pyrroles with broad scope from N-propargyl-tethered ynamides. In contrast, N-homopropargyl-tethered ynamides undergo intramolecular tetradehydro Diels-Alder reaction to provide 2,3-dihydro-benzo[f]indole derivatives. Control experiments and density-functional theory studies were used to study the reaction pathways.