Synthesis and physico-chemical characterization of metal free, sodium and potassium phthalocyanine complexes

Sodium phthalocyanine (Na₂Pc), potassium phthalocyanine (K₂Pc) and hydrogen phthalocyanine (H₂Pc) are synthesized in pure state. These complexes are characterized using physico-chemical methods like electronic, IR spectral, magnetic susceptibility measurements, thermogravimetric analysis and X-ray powder diffraction studies. Kinetic and thermodynamic parameters associated with the thermal decomposition were calculated using thermogravimetric analytical data. X-ray diffraction studies revealed that these complexes are having monoclinic crystal lattice structure. Electrical conductivity studies are carried out using two-probe technique in the temperature range 298-473 K for each complex. Sodium phthalocyanine showed semiconducting behavior, whereas potassium phthalocyanine showed first metallic behavior in the temperature range 300-378 K and then semiconducting property in the temperature range 383-473 K. But hydrogen phthalocyanine showed semiconducting behavior in the temperature range 300-390 K and metallic conduction behavior in the temperature range 395-473 K.     

Effect of gas mixing on Xe ion currents from an ECR ion source

Gas mixing technique has been used in order to increase the current of highly charged ions of Xe at the TIFR-ECRIA. The He, N₂, O₂, Ne, and Ar are used as support gases, and their effect on output currents of Xe ions is studied. The effective ion charge and the total loss rate of ions are calculated from the measured currents. It is found that molecular gases, such as N₂ and O₂, exhibit better mixing effect in the enhancement of output of highly charged Xe ions. Furthermore, we describe this 14.5-GHz ECR ion source mounted on a high voltage (400 kV) deck, with its four beamlines, as well as the control system for the remote operation.     

Dendrimer-rhodium nanoparticle modified glassy carbon electrode for amperometric detection of hydrogen peroxide

Metallic nanoparticles of rhodium were prepared by using the newly synthesized N,N-bis-succinamide-based dendrimer as stabilizers. The Rh nanoparticles were spherical shaped with a particle size of ∼2 nm. The dendrimer Rh-encapsulated nanoparticles (Rh-DENs) were immobilized on glassy carbon electrode (GCE) and their electrocatalytic activity towards hydrogen peroxide reduction was investigated using cyclic voltammetry and chronoamperometry. The Rh-DENs modified GCE showed excellent electrocatalytic activity for hydrogen peroxide reduction reactions. The steady-state cathodic current response of the modified electrode at −0.3 V (vs SCE) in phosphate buffer (pH 7.0) showed a linear response to hydrogen peroxide concentration ranging from 8 to 30 μM with a detection limit and sensitivity of 5 μM and 0.03103 × 10⁻⁶ A μM⁻¹, respectively.     

Electrostatically self-assembled azides on zinc sulfide nanoparticles as multifunctional nanoprobes for peptide and protein analysis in MALDI-TOF MS

A simple method to synthesize electrostatically self-assembled azides on zinc sulfide nanoparticles (ZnS-N₃ NPs) was described and then it was further applied as a multifunctional nanoprobe such as enriching, desalting, accelerating and separation-/washing free nanoprobes for rapid analysis of peptides and proteins and microwave assisted tryptic digested proteins in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The ZnS-N₃ NPs were characterized by UV-vis, FT-IR, SEM and TEM spectroscopy. The ZnS-N₃ NPs can effectively enrich signal intensities for 2-10 times for various peptides and proteins including HW6, insulin, ubiquitin, cytochrome c, lysozyme, myoglobin and bovine serum albumin (BSA) in MALDI-TOF MS. Furthermore, we also demonstrated that the ZnS-N₃ NPs can serve as accelerating probes for microwave assisted tryptic digestion of proteins in MALDI-TOF MS. The applicability of the present method on complex sample analysis such as milk proteins from cow milk and ubiquitin and ubiquitin like proteins from oyster mushroom were also demonstrated.     

Centrality dependence of freeze-out parameters from Au+Au collisions at \sqrt {s_{NN} } = 7.7, 11.5 and 39 GeV

The RHIC beam energy scan program in its first phase collected data for Au+Au collisions at beam energies of 7.7, 11.5 and 39 GeV. The event statistics collected at these lower energies allow us to study the centrality dependence of various observables in detail, and compare to fixed-target experiments at SPS for similar beam energies. The chemical and kinetic freeze-out parameters can be extracted from the experimentally measured yields of identified hadrons within the framework of thermodynamical models. These then provide information about the system at the stages of the expansion where inelastic and elastic collisions of the constituents cease. We present the centrality dependence of freeze-out parameters for Au+Au collisions at midrapidity for $\sqrt {s_{NN} } $ = 7.7, 11.5, and 39 GeV from the STAR experiment. The chemical freeze-out conditions are obtained by comparing the measured particle ratios (involving ??, K, p, and p) to those from the statistical thermal model calculations. The kinetic freeze-out conditions are extracted at these energies by simultaneously fitting the invariant yields of identified hadrons (??, K, and p) using Blast Wave model calculations.     

Spectroscopic characterization and EPR spectral studies on transition metal complexes with a novel tetradentate, 12-membered macrocyclic ligand

Complexes of Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) containing a tetradentate macrocyclic N-donor ligand have been prepared via template reaction of 2,3-pentanedione, ethylene-di-ammine and transition metal ions. The complexes have been characterized on the basis of the elemental analysis, molar conductance, magnetic moment susceptibility, IR, electronic and EPR spectral studies. The complexes are of high spin type and possess four coordinate tetrahedral five coordinate square pyramidal and six coordinated octahedral/tetragonal geometry.     

Nanoparticle-based sensing of glycan-lectin interactions

Here we present the first report on nanoparticle-based biosensing of glycan markers of diseases. The protocol relies on the competition between a nanocrystal (CdS)-tagged sugar and the target sugar for the binding sites of surface-confined lectin and monitoring the extent of competition through highly sensitive electrochemical detection of the captured nanocrystal. This development is expected to allow decentralized detection of carbohydrate moieties and lectin-carbohydrate interactions to be performed more rapidly, sensitively, inexpensively, and reliably.     

A stereocontrolled total synthesis of (±)-norzizanone

A stereocontrolled total synthesis of (±)-norzizanone 1 has been efficiently accomplished involving base-induced rearrangement of the mesylate 17 as the key step. Aryl participated intramolecular cyclisation of the bromophenol 11 provided the tricyclic dienone 12, which was stereoselectively converted into the mesylate 17.     

Synthesis,Characterization and Photophysical Studies of Tricoumarin-Pyridines

A series of novel tricoumarin-pyridines have been synthesized by the reaction of 4-formyl coumarins and substituted 3-acetylcoumarin with ammonium acetate for the application in organic electronics as well as fluorescent dyes. The structures of all new compounds were confirmed and characterized by IR, ¹H NMR and ESI-Mass analysis. All the important photo physical prerequisites for organic electronic application such as strong and broad optical absorption, thermal stability were determined for the synthesized molecules. Optical properties were studied by UV-Vis absorption and fluorescence spectroscopy. Optical band gaps of the tricoumarin-pyridines were found to be 2.72–3.10 eV as calculated from their onset absorption edge. The tricoumarin-pyridines were thermally stable up to 290–370 °C as determined by thermogravimetric analysis (TGA). Photophysical studies indicate the synthesized materials are promising candidates for organic electronic applications.     

Bianchi Type V Barotropic Perfect Fluid Cosmological Model in Lyra Geometry

We have investigated Bianchi Type V barotropic perfect fluid cosmological model in Lyra geometry. To get the deterministic model of the universe, we have assumed the barotropic perfect fluid condition p=γ ρ, 0≤γ≤1 and energy conservation equation i.e. T _i;j ^j =0. The physical and geometrical aspects of the model are discussed. The special cases for γ=1 (stiff fluid distribution), γ=0 (dust distribution), γ=1/3 (disordered radiation) are also discussed.