Search

Your search keyword '"Maiya, Bhaskar G."' showing total 230 results
Start Over Author "Maiya, Bhaskar G."
230 results on '"Maiya, Bhaskar G."'

9. Fluoride ion receptors based on dipyrrolyl derivatives bearing electron-withdrawing groups: Synthesis, optical and electrochemical sensing, and computational studies

Author

Ghosh, Tamal, Maiya, Bhaskar G., and Ming Wha Wong

Subjects
Receptor antibodies -- Research, Intermolecular forces -- Research, Fluorides -- Atomic properties, Chemicals, plastics and rubber industries
Abstract

The underlying intermolecular interactions of the receptors anion complexes along with the insight into the structures, intrinsic binding affinities that supports the experimental characterization via computations of NMR and UV-visible spectra is studied. DFT calculations lend further support affinity and high selectivity of the fluoride ion for receptors.

Published
2004

17. Enhanced optical limiting and nonlinear absorption properties of azoarene-appended phosphorus (V) tetratolylporphyrins

Author

Kiran, P. Prem, Reddy, D. Raghunath, Maiya, Bhaskar G., Dharmadhikari, Aditya K., Kumar, G. Ravindra, and Desai, Narayana Rao

Subjects
Absorption of light -- Research, Porphyrins, Astronomy, Physics
Abstract

Optical limiting performance, third-order nonlinearity [[chi].sup.(3)], and nonlinear absorption properties have been investigated in a new class of azoarene phosphorus (V) porphyrins with charge transfer (CT) states. The introduction of axial azoarene groups into the phosphorus porphyrin structure is found to reduce the limiting threshold by a factor of 2 and lead to a rise in the second hyperpolarizability by 1 order of magnitude in the picosecond time regime and by 2 orders of magnitude in the nanosecond regime. The experimental data show reverse saturation of absorption in the nanosecond time regime and a saturation of the nonlinear absorption above a fluence of 0.5 J/[cm.sup.2] in the picosecond regime. The presence of the CT state reduces saturation of excited-state absorption (ESA) in the [S.sub.1] [right arrow] [S.sub.n] transition through the [S.sub.1] [right arrow] CT transition. Faster CT [right arrow] [T.sub.1] transition increases the ESA from [T.sub.1] [right arrow] [T.sub.n] states in the nanosecond regime. A self-consistent theoretical analysis based on rate equations is used to estimate the high-lying excited-state lifetimes and absorption cross sections from the experimental results. OCIS codes: 190.0190, 190.4360, 190.4710, 140.3360.

Published
2002

19. New molecular arrays based on a tin(IV) porphyrin scaffold

Author

Kumar, A. Ashok, Giribabu, L., Reddy, D. Raghunath, and Maiya, Bhaskar G.

Subjects
Chemistry, Inorganic -- Research, Tin -- Physiological aspects, Porphyrins -- Physiological aspects, Molecules -- Analysis, Metal ions -- Physiological aspects, Chemistry
Abstract

Research has been conducted on the porphyrin arrays, a hexamer and a nonamer. The synthesis and characterization of these arrays have been carried out via elemental analysis and spectroscopic methods, and the results indicate that the construction scheme of these arrays involves sequential organic and inorganic reactions performed at the central tin(IV) ion of the porphyrin scaffold and at the peripheral meso-phenyl ring.

Published
2001

20. Ruthenium(II) complexes of 6,7-dicyanodipyridoquinoxaline: synthesis, luminescence studies, and DNA interaction

Author

Ambroise, Arounaguiry, Maiya, Bhaskar G., Munakata, Megumu, Kuroda-Sowa, Takayoshi, Maekawa, Masahiko, Suenaga, Yusaku, and Kitamori, Yoshinobu

Subjects
Nuclear magnetic resonance spectroscopy -- Usage, Ruthenium -- Spectra, Ruthenium -- Structure, Ruthenium -- Chemical properties, Chemistry, Inorganic -- Research, Chemistry
Abstract

The syntheses, spectral characterizations, DNA interactions and electrochemical properties of mono, bis, and tris complexes of a new dipyridophenazine-based ligand, dicnq (6,7-dicyanodipyrido[2,2-d:2',3'-f]quinoxaline), are described. The detailed luminescence studies indicate that [Ru(phen)(sub 2)(dicnq)(sub 2)](super 2+) are moderately efficient molecular light switches for DNA.

Published
2000

21. Ruthenium(II) complexes of redox-related, modified dipyridophenazine ligands: synthesis, characterization, and DNA interaction

Author

Ambroise, Arounaguiry, Maiya, Bhaskar G., Schrobilgen, Gary J., Hascall, Tony, and Parkin, Gerard

Subjects
Electron transport -- Research, Ruthenium -- Structure, Ruthenium -- Chemical properties, Ruthenium -- Electric properties, Chemistry, Inorganic -- Research, Chemistry
Abstract

The synthesis, spectral characterization, and electrochemical properties of [Ru(phen)(sub 2)(qdppz)](super 2+), which incorporates a quinone-fused dipyridophenazine ligand (naphtho[2,3-a]dipyrido[3,2-h:2',3'-f]phenazine-5,18-dione, qdppz), are described. The photoinduced electron transfer from the MLCT state to the quinone acceptor in [Ru(phen)(sub 2)(qdppz)](super 2+) and quenching of the excited states due to proton transfer from water to the dipyridophenazine ligand in both complexes are invoked to rationalize the apparent lack of emission of these redox-related complexes in the DNA medium.

Published
2000

22. 'Axial-bonding'-type hybrid porphyrin arrays: synthesis, spectroscopy, electrochemistry, and singlet state properties

Author

Giribabu, L., Rao, T. Anita, and Maiya, Bhaskar G.

Subjects
Chemistry, Inorganic -- Research, Electrochemistry -- Analysis, Spectrum analysis -- Usage, Phosphorus -- Research, Germanium -- Research, Tin -- Research, Chemistry
Abstract

Research has been conducted on the construction of the phosphorus, germanium and tin phorphyrin-based hybrid trimers. The use of a new building block approach is discussed.

Published
1999

24. Aryloxo derivatives of phosphorus(V) porphyrins. Synthesis, spectroscopy, electrochemistry, and singlet state properties

Author

Rao, T. Anita and Maiya, Bhaskar G.

Subjects
Porphyrins -- Research, Phosphorus compounds -- Research, Chemistry
Abstract

Six aryloxo phosphorus(V) porphyrins, of the class (TpTP P OR 2)+OH- where TpTP is the dianion of tetra-pp-tolylporphyrin and OR is an axial aryloxo ligand, are synthesized and then characterized spectrally, electrochemically, and photochemically. A characteristic charge transfer state of the type P(V)(super -)-OR(super +) in the excited state deactivation of the compounds determines them to be the unique representatives of porphyrin-based donor-acceptor compounds.

Published
1996

25. Dipyridophenazine complexes of cobalt(III) and nickel(II): DNA-binding and photocleavage studies

Author

Arounaguiri, S. and Maiya, Bhaskar G.

Subjects
DNA-ligand interactions -- Research, Nickel compounds -- Research, Complex compounds -- Analysis, Cobalt -- Research, Chemistry
Abstract

Thermal denaturation, absorption titration and differential-pulse voltammetric studies indicate that (Co(phen)2DPPZ)3+ and (Ni(phen)2DPPZ)2+, where phen = 1,10-phenanthroline and DPPZ = dipyrido(3,2-a:2',3'-c)phenazine, bind DNA. Substitution by different metal ions changes the properties and the DNA interactions of the complexes. The cobalt(III) complex effectively cleaves supercoiled pBR 322 DNA in the presence of light while the nickel(II) complex fails to do so.

Published
1996

27. Abstracts

Author

Basu, J., Rohatgi-Mukherjee, K. K., Chatterjee, S., Sarkar, S., Bhattacharyya, S. N., Dasmahapatra, G. K., Wolff, Thomas, Von Bunau, Gunther, Dhawan, S. N., Sen, Dipankar, Bera, Subhash Ch, Gupta, S. C., Yadav, N. S., Sahu, Manabendra, Saha, Manjubikash, Masilamani, V., Sastikumar, D., Behera, Pradipta Kumar, Mishra, Ashok Kumar, Muthusamy, S., Ramakrishnan, V. T., Ramamurthy, P., Sampath, S., Narayan, R., Manickam, M. C. Durai, Srinivasan, C., Pitchumani, K., Roja, M., Rajagopal, S., Ray, Reba, Mukherjee, Samaresh, Samanta, A., Natarajan, E., Selvaraj, S., Natarajan, P., Talwar, S. S., Viswanathan, K., Natarajan, P., Dhathathreyan, Aruna, Dhathathreyan, K. S., Biswal, Basanti, Song, Pill-Soon, Das, S., Muneer, M., Haridas, A., Manilal, V. B., Jayakumar, R., Ramasami, T., Julliard, M., Chanon, M., Joshi, P. N., Biswal, U. C., Joshy, C. L., Purushothaman, E., Maiya, Bhaskar G., Ganesan, S., Nagarajan, B., Narayanan, V., Mohanty, Prasanna, Shubin, V., Murthy, S. D. S., Karapetyan, N. V., Ramaraj, R., Gobi, K. V., Sankareswari, V. Gomathi, Ranganayaki, S., Bahadur, K., Kumar, Sajal, Sonawane, H. R., Kulkarni, D. G., Ayyangar, N. R., Sukumar, N., Venkitachalam, T. V., Rao, A. S., Ali, S. I., Kaur, Harpal, Anbalagan, V., Srivastava, T. S., Kumar, Awadhesh, Chowdhury, P. K., Rao, K. V. S. Rama, Mittal, J. P., Balasubramanian, N., Balasubramanian, S., Dutt, G. B., Doraiswamy, S., Manna, Bidyut Kumar, Rohatgi-Mukherjee, K. K., Chandra, A., Bagchi, B., Arunachalam, S., Devadason, J. R., Dhanasekaran, T., Prabahar, K. Joseph, Mathew, Lizamma, Ramakrishnan, V., Rajaram, J., Rao, V. R. S., Narayanan, P., Pillai, V. N. Sivasankara, Priyadarsini, K. I., Rajendran, T., Palaniandavar, M., Kaneko, M., Kira, A., Sidhu, M. S., Chopra, Arti, Gill, Barinder, Baby, Thomas, and Nampoori, V. P. N.

Published
1992
Full Text
View/download PDF

29. Abstracts of posters presented at the symposium

Author

Maiya, Bhaskar G., Chauhan, S. M. S., Bhyrappa, P., Krishnan, V., Bhardwaj, P. K., Sarkar, Sabyasachi, Pandeya, Krishna B., Mathur, Pavan, Chakravarty, Akhil R., Das, Birinchi K., Behere, Digambar V., Modi, Sandeep, Mitra, Samaresh, Modi, Sandeep, Behere, Digambar V., Mitra, Samaresh, Saxena, Anil, Modi, Sandeep, Behere, Digambar V., Mitra, S., Mazumdar, Shyamalava, Medhi, Okhil K., Mitra, Samaresh, Mazumdar, Shyamalava, Mitra, Samaresh, Madan, Anup, Modi, Sandeep, Saxena, Anil, Behere, Digamber V., Mitra, S., Pandiyan, T., Palaniandavar, M., Narayanan, K. L., Manohar, H., Ramaraj, R., Thomas, C. C., Rajagopal, S., Rajendra, T., Srinivasan, C., Ramamurthy, P., Roy, R., Saha, M. C., Panchanan, S., Roy, P. S., Balagopalakrishna, C., Rajasekharan, M. V., Agarwala, B. V., Hingorani, S., Gowda, G. A. Nagena, Ramaswamy, Y. S., Halesha, R., Gowda, N. M. N., Reddy, G. K. N., Saxena, G. C., Gupta, K. L., Srivastava, P., Gupta, V. D., Ray, M., Mukherjee, R. N., Mohanty, R. N., Dash, K. C., Kapoor, Ramesh, Yadav, S., Sood, V., Kapoor, P., Anand, B. N., Bains, R., Usha, Aggarwal, K., Garge, P., Chikate, R., Padhye, S., Savariault, J. M., De Loth, P., Tuchgues, J. P., Jain, V. K., Vaidya, M. A., Jain, S. C., Kumar, S. Kalyan, Singh, Harkesh B., Mangaonkar, K. M., Patkar, D. N., Jha, N. K., Sharma, Pankaj, Date, S. K., Deshpande, C. E., Sathaye, S. D., Deshpande, S. B., Potdar, H. S., Darshane, V. S., Dash, A. C., Nanda, R. K., Das, N. N., Gangopadhyay, S., Banerjee, P., Kulshreshtha, S. K., Zacharias, P. S., Arulsamy, N., Ramasami, T., Subramanian, V., Nair, B. U., Kanthimathi, M., Sundararajan, G., Shivasubramanian, V., Bhattacharya, R. G., Biswas, S., Armstrong, J., Holt, E. M., and Koley, A. P.

Published
1990
Full Text
View/download PDF

35. Redox control of photoinduced electron transfer in axial terpyridoxy porphyrin complexes

Author

Poddutoori, Prashanth Kumar, Poddutoori, Premaladha, Maiya, Bhaskar G., Prasad, Thazhe Kootteri, Kandrashkin, Yuri E., Vasil'ev, Sergei, Bruce, Doug, and van det Est, Art

Subjects
Tin compounds -- Optical properties, Tin compounds -- Electric properties, Redox potential -- Analysis, Aluminum -- Optical properties, Aluminum -- Electric properties, Electron transport -- Research, Chemistry
Abstract

The photophysical properties of axial-bonding types (terpyridoxy)aluminum(III) prophyrin (Al(PTP)), bis(terpyridoxy)tin(IV) porphyrin (Sn[(PTP).sub.2]) and bis(terpyridoxy)phosphorus(V) porphyrin ([[P[(PTP).sub.2]].sup.+]) are analyzed. The results have clarified the role of the internal molecular structure and the reduction potential for electron transfer from the terpyridine ligand to the excited porphyrin.

Published
2008

36. Crystal structures of PNA-porphyrin complex in the presence and absence of lactose: Mapping the conformational changes on lactose binding, interacting surfaces, and supramolecular aggregations

Author

Goel, Manisha, Damai, Rajani S., Sethi, Dhruv K., Kaur, Kanwal J., Maiya, Bhaskar G., Swamy, Musti J., and Salunke, Dinakar M.

Subjects
Agglutinins -- Chemical properties, Lactose -- Structure, Lactose -- Chemical properties, Porphyrins -- Structure, Porphyrins -- Chemical properties, Biological sciences, Chemistry
Abstract

Crystal structures of meso-tetrasulfonatophenylporphyrin (H(sub 2)TPPS) bound to peanut agglutinin (PNA) in the presence and absence of lactose are determined. It is found that the structures provide a possible native conformation of the carbohydrate-binding site of PNA in the absence of the ligand that highlight mapping of the unsaturated binding surfaces of PNA using interactions.

Published
2005

37. Ultrafast intramolecular electronic energy-transfer dynamics in a bichromophoric molecule

Author

Mondal, Jahur A., Ramakrishna, G., Singh, Ajay K., Ghosh, Hirendra N., Maiya, Bhaskar G., Mariappan, M., Mukherjee, Tulsi, and Palit, Dipak K.

Subjects
Dynamics -- Research, Electron transport -- Research, Chemical synthesis -- Research, Chemicals, plastics and rubber industries
Abstract

Intramolecular electronic energy-transfer (intra-EET) dynamics are investigated in 2-(9-anthryl)-1H-imidazo [4,5-f] [1,10]-phenanthroline (AIP), a newly synthesized bichromophoric molecule by using the steady state and time resolved absorption and fluorescence spectroscopic techniques. In AIP anthracene (AN) and 1H-imidazo [4,5-f] [1,10]-phenanthroline (IP) molecules are directly linked to each other through a C-C sigma bond without any intervening molecular bridge.

Published
2004

38. Phosphorous(V) porphyrin-azoarene conjugates: synthesis, spectroscopy, cis-trans isomerization, and photoswitching function`

Author

Reddy, Raghunath D., Maiya, Bhaskar G., Cimas, Alvaro, Antonio, Largo, and Schaefer, Henry F. III

Subjects
Porphyrins -- Chemical properties, Phosphorus -- Chemical properties, Isomerization -- Research, Chemicals, plastics and rubber industries
Abstract

The successful demonstration of the photoswitching function by a prototype phosphorous (V) [P(V)] porphyrin-azobenzene system, the design, the synthesis, spectral characterization, and cis-trans isomerization is described. The occurrence of reversible cis-trans isomerization of the porpherene bound azorene subunits in the class of porphyrin-azoarene (P-A) conjugates, are clearly suggested by the observations.

Published
2003

42. 'Electro-photo switch' and 'molecular light switch' devices based on ruthenium(II) complexes of modified dipyridophenazine ligands: modulation of the photochemical function through ligand design

Author

Arounaguiri, S. and Maiya, Bhaskar G.

Subjects
Ruthenium -- Research, Coordination compounds -- Research, Ligands -- Research, Polycyclic compounds -- Research, Photochemistry -- Analysis, Chemistry
Abstract

Both (Ru(phen)2(qdppz))2+ and (Ru(phen)2(dicnq))2+ have interesting photochemical characteristics depending on the properties of the coordinated dipyridophenazine-based ligand in them. It was observed that while the redox couple (Ru(phen)2(qdppz))2+/(Ru(phen)2(hqdppz))2+ represents an electro-photo switch, (Ru(phen)2(dicnq))2+ is an efficient molecular light switch for DNA. Hence, the architectural complexities and electronic structures of the new dppz-based ligands are essential in predicting the useful photochemical characteristics of their complexes.

Published
1999

43. Photodynamic viral deactivation with sapphyrins

Author

Judy, Millard M., Harriman, Anthony M., Matthews, J. Lester, Newman, Joseph T., Sessler, Jonathan L., Sogandares-Bernal, Frank, and Maiya, Bhaskar G.

Subjects
C07D487/22, A61K47/546, A61L2/0011, A61L2/0088, 540/145, A61K41/0038, A61K41/0076, 604/6.8
Abstract

The present invention demonstrates a method of photodynamic inactivation of viruses having a membranous envelope, such as Herpes simplex type 1 and Human immunodeficiency type 1 viruses. The method uses substituted sapphyrin compounds to effect viral deactivation during radiation with light at or near the absorption wavelength of the sapphyrin compound. A highly reactive species selectively toxic to infectious agents is produced. One particular sapphyrin compound useful for the practice of the invention is 8,17-bis(carboxymethyl)-3,12,13,22-tetraethyl-2,7,18,23-tetramethylsapphyr in (Sapphyrin 2). The most preferred sapphyrin sapphyrin compound for the practice of the invention is 3,8,12,13,17,22-hexaethyl-2,7,18,23-tetramethylsapphyrin (Sapphyrin 1). The method is particularly suitable for inactivation of viruses in blood and blood products.

Published
1991
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results