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Item Synthesis of worm-shaped carbon nanofibers over a sodium chloride support(2012) Ravindra, R.; Badekai Ramachandra, B.R.Worm-shaped carbon nanofibers (WCNFs) were synthesized in bulk by chemical vapour deposition at 680 °C using iron carboxylate as catalyst precursors and sodium chloride as catalyst support. The products were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction method. The purity of the purified products was determined by thermal analysis. TheWCNFyield was 6700% relative to catalyst. The simplicity, environmental friendliness and use of easily available low-cost precursors are the advantage of this synthesis technique. © Springer Science+Business Media B.V. 2012.Item Large scale synthesis of carbon nanofibres on sodium chloride support(InTech Europe info@sagepub.co.uk, 2012) Rajarao, R.; Badekai Ramachandra, B.R.Large scale synthesis of carbon nanofibres (CNFs) on a sodium chloride support has been achieved. CNFs have been synthesized using metal oxalate (Ni, Co and Fe) as catalyst precursors at 680 °C by chemical vapour deposition method. Upon pyrolysis, this catalyst precursors yield catalyst nanoparticles directly. The sodium chloride was used as a catalyst support, it was chosen because of its non-toxic and water soluble nature. Problems, such as the detrimental effect of CNFs, the detrimental effects on the environment and even cost, have been avoided by using a water soluble support. The structure of products was characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The purity of the grown products and purified products were determined by the thermal analysis and X-ray diffraction method. Here we report the 7600, 7000 and 6500 wt% yield of CNFs synthesized over nickel, cobalt and iron oxalate. The long, curved and worm shaped CNFs were obtained on Ni, Co and Fe catalysts respectively. The lengthy process of calcination and reduction for the preparation of catalysts is avoided in this method. This synthesis route is simple and economical, hence, it can be used for CNF synthesis in industries. © 2012 Rajarao and Bhat.Item Thermal and antibacterial studies of novel lanthanide-schiff base complexes(2012) Ramasubramanian, A.S.; Badekai Ramachandra, B.R.; Dileep, R.Novel lanthanide complexes with the general formula [Ln(L)(ONO 2)(H 2O) 2] have been synthesized and characterized. {L = 5-bromosalicylidene 4-amino 3-mercapto-1,2,4-triazine-5-one (BrSAMT), Ln = La(III), Ce(III), (Pr(III) Eu(III), Sm(III), Nd(III), Tb(III), Dy(III), and Y(III)}. The thermal, magnetic, molar conductance, and spectral studies confirm that the ligand coordinates through sulfur, azomethine nitrogen, and phenolic oxygen. A scheme of thermal decomposition of the complexes is also proposed. La, Eu, and Yb complexes of BrSAMT show antibacterial activity against gram negative bacteria such as E. coli, Pseudomonas aeruginosa, Salmonella typhi, and Shigella flexneri. Copyright © Taylor & Francis Group, LLC.Item Nonlinear optical study of palladium Schiff base complex using femtosecond differential optical Kerr gate and Z-scan techniques(2012) Rudresha, B.J.; Badekai Ramachandra, B.R.; Ramakrishna, D.; Anthony, J.K.; Lee, H.W.; Rotermund, F.A femtosecond differential optical Kerr gate (DOKG) and Z-scan techniques, have been applied to investigate the third-order optical nonlinearity of composite film of the coordination complex [PdLPPh 3] (L=N-(2-pyridyl)-N'-(salicylidene)hydrazine, PPh 3=triphenylphosphine) . Film exhibits superior nonlinear optical properties in the near-infrared spectral region. The nonlinear response time and third-order nonlinear optical susceptibility of complex were found to be?90 fs and 3.9×10 -10 esu, respectively. The Z-scan result shows that saturable absorption property of the film and its nonlinear absorption coefficient of the sample was found to be -23 cm/GW. © 2011 Elsevier Ltd. All rights reserved.Item Octupolar metal complexes for third order nonlinear optical studies(2012) Rudresha, B.J.; Manjunatha, K.B.; Umesh, G.; Badekai Ramachandra, B.R.The octupolar metal complexes [Zn(bpy)(L)] (1), [Cd(bpy)(L)] (2), [Hg(bpy)(L)] (3) (bpy = 2,2?-bipyridyl, L = 4-dimethylamino-?- cyanocinnamic acid) have been synthesized. The third-order nonlinear optical properties of complexes were studied using Z-scan technique at 532 nm with nanosecond laser pulses. The complexes show optical limiting behavior. The values of the effective two-photon absorption (2PA) coefficients (?), third-order nonlinear susceptibilities (? (3)) and two-photon absorption cross sections (? 2) are calculated. Results show, lewis acidity of metal center and molecular symmetry are two important factors for observed large TPA cross-section of metal complexes. © 2012 Elsevier B.V. All rights reserved.Item Multi-walled carbon nanotube bound nickel Schiff-base complexes as reusable catalysts for oxidation of alcohols(2012) Rajarao, R.; Kim, T.H.; Badekai Ramachandra, B.R.Nickel salen and salophen complexes have been covalently anchored on multi-walled carbon nanotubes (MWNTs). The MWNT-supported nickel complexes have been characterized by inductive coupled plasma spectroscopy, FT-IR spectroscopy, UV-Vis spectrophotometry, transmission electron microscopy, and X-ray diffraction. The catalytic performance for the oxidation of primary and secondary alcohols was evaluated using periodic acid as oxidant. Reaction conditions have been optimized for MWNT-supported salen and salophen complexes by considering the effect of parameters such as solvent, reaction time, concentration of catalyst, amount of oxidant, etc. The catalytic activity was higher for supported catalysts than similar homogeneous ones. These supported catalysts were highly stable and reused several times without the loss of catalytic activity. © 2012 Taylor & Francis.Item Bulk scale production of carbon nanofibers in an economical way(2012) Rajarao, R.; Badekai Ramachandra, B.R.An economical route for the scalable production of carbon nanofibers (CNFs) on a sodium chloride support has been developed. CNFs have been synthesized by chemical vapor deposition (CVD) method by using metal formate as catalyst precursors at 680°C. Products were characterized by SEM, TEM, Raman spectroscopy and XRD method. By thermal analysis, the purity of the as grown products and purified products were determined. This method avoids calcination and reduction process which was employed in commercial catalysts such as metal oxide or nitrate. The problems such as detrimental effect, environmental and even cost have been overcome by using sodium chloride as support. The yield of CNFs up to 7800 wt.% relative to the nickel catalyst has been achieved in the growth time of 15 min. The advantage of this synthesis technique is the simplicity and use of easily available low cost precursors. © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg.Item Single-step oxidative homocoupling of aryl Grignard reagents via Co(II), Ni(II) and Cu(II) Complexes under air(John Wiley and Sons Ltd Southern Gate Chichester, West Sussex PO19 8SQ, 2014) Bhat, A.P.I.; Badekai Ramachandra, B.R.A simple catalytic system of direct synthesis for the symmetrical biaryls using catalytic amounts of Co(II), Ni(II) and Cu(II) complexes has been developed. The reaction system involves in situ synthesis of Grignard reagents. The complexes, containing bidentate Schiff base and dmit (2-thioxo-1,3-dithiole- 4,5-dithiolate) ligands, were compatible with diverse functionalities and afford a high yield of biaryls in a single step, proving to be promising catalysts in homocoupling reactions. Atmospheric oxygen is used as an oxidant which renders a green, simple and economical catalytic route. Copyright © 2014 John Wiley & Sons, Ltd.Item Cobalt complex in a room temperature ionic liquid: A convenient recyclable reagent for catalytic epoxidation of cyclic alkenes(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2014) Ramakrishna, D.; Badekai Ramachandra, B.R.; Hanumanthappa, S.K.T.Co-catalyzed epoxidation of cyclic alkenes proceeds in ionic liquid media (1-ethyl-3-methylimidazolium hexafluorophosphate). Epoxidation of the alkenes to respective epoxides was greatly accelerated by the use of a cobalt-based catalyst in the presence of H2O2 as an oxidant. The catalyst in ionic liquid [Emim]PF6 was recycled and reused for about seven times. © 2014 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.Item Structural health monitoring capabilities in ceramic-carbon nanocomposites(2014) Inam, F.; Badekai Ramachandra, B.R.; Vo, T.; Daoush, W.M.A novel method for analysing structural health of alumina nanocomposites filled with graphene nanoplatelets (GNP), carbon nanotubes (CNTs) and carbon black nano-particles (CB) is presented. All nanocomposites were prepared using novel colloidal processing and then by Spark Plasma Sintering. Good homogeneous dispersion was observed for all carbon filled materials. Nanocomposite bars were indented to produce sub-surface damage. Change in electrical conductivities were analysed after indentation to understand structural damage. For correlating change in electrical conductivity and indentation damage and understanding damage tolerance, mechanical properties were compared. Because of the systematically induced indentation damage, a sharp decrease of 86% was observed in the electrical conductivity of CNT nanocomposite as compared to 69% and 27% in the electrical conductivities of GNP nanocomposites and CB nanocomposites respectively. CNTs impart superior damage sensing capability in alumina nanocomposites, in comparison to GNP and CB, due to their fibrous nature, high aspect ratio and high electrical conductivity. © 2013 Elsevier Ltd and Techna Group S.r.l.