Muhammad Farooq Warsi

In situ hydrogenation of molybdenum oxide nanowires for enhanced supercapacitors

In situ hydrogenation of orthorhombic molybdenum trioxide (α-MoO3) nanowires has been achieved on a large scale by introducing alcohol during the hydrothermal synthesis for electrochemical energy storage supercapacitor devices. The hydrogenated molybdenum trioxide (HxMoO3) nanowires yield a specific capacitance of 168 F g−1 at 0.5 A g−1 and maintain 108 F g−1 at 10 A g−1, which is 36-fold higher than the capacitance obtained from pristine MoO3 nanowires at the same conditions. The electrochemical devices made with HxMoO3 nanowires exhibit excellent cycling stability by retaining 97% of their capacitance after 3000 cycles due to an enhanced electronic conductivity and increased density of hydroxyl groups on the surface of the MoO3 nanowires.

Structural and electromechanical behavior evaluation of polymer-copper nanocomposites

Copper nanoparticles were prepared by chemical reduction of copper nitrate by sodium borohydride as a reducing agent in de-ionized water/acetonitrile mixture. The prepared nanoparticles were incorporated in poly(vinyl alcohol) (PVA) by physical dispersion method to obtain PVA/copper nanocomposites. Various compositions of nanocomposites were obtained by changing the w/w ratio of nanoparticles with the polymeric material. The prepared nanocomposites cast into films of uniform thickness. The composite films were subjected to the electrical, mechanical and surface morphology characterization. AC Impedance was figured out by AC Impedance analyser. The results illustrated that copper nanoparticles impart electrical conductivity in poly(vinyl alcohol). Moreover, electrical conductivity of the composites exhibited an increase with an increase of w/w% of the copper nanoparticles in poly(vinyl alcohol). Tensile properties were studied in terms of tensile strength, elongation at break and Young’s modulus. Elongation at break and Young’s modulus values demonstrated an increase while tensile strength displayed a decrease at higher concentration of the copper nanoparticles in the composites. AFM results unfolded the surface morphology of the composites illustrating a smooth surface with evenly distributed copper nanoparticles in the polymer matrix. The dimensions of the uneven surface is attributed to the copper nanoparticles were estimated to be of a range less than 100 nm. The prepared nanocomposites are suggested as potential candidates in charge storing devices.

Cyclic‐RGD penta‐peptides cRGDyK derivatized with cyclopentadienyl complexes of technetium and rhenium as radiopharmaceutical probes

The present study reports the syntheses of half-sandwich complexes of the type [M(η5 -C5 H4 CONH-R)(CO)3 ] (M═Re,99m Tc;R═cyclic RGD peptide (cRGDyK) for potential imaging of αv β3 integrin expression. The 99m Tc complex was prepared directly from the reaction of [99m Tc(OH2 )3 (CO)3 ]+ with cRGDyK, doubly conjugated to Thieles acid [(C5 H5 COOH)2 ] in water. This approach extends the viability of metal-mediated retro Diels-Alder reactions for the preparation of small molecules such as linear tripeptides to a more complex cyclic peptide carrying a [(η5 -C5 H4 )99m Tc(CO)3 ] tag. The Diels-Alder product [(C5 H5 CONH-cRGDyK)2 ] was prepared from Thieles acid via double peptide coupling. The Re-complex [Re(η5 -C5 H4 CONH-cRGDyK)(CO)3 ] was obtained by attaching [Re(η5 -C5 H4 COOH)(CO)3 ] directly to the N-terminus of cRGDyK. The identity of the 99m Tc-complex is confirmed by chromatographic comparison with the corresponding rhenium complex, fully characterized by spectroscopic techniques.