41 results on '"Manas K. Panda"'
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2. A switchable self-assembling and disassembling chiral system based on a porphyrin-substituted phenylalanine–phenylalanine motif
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Georgios Charalambidis, Evangelos Georgilis, Manas K. Panda, Christopher E. Anson, Annie K. Powell, Stephen Doyle, David Moss, Tobias Jochum, Peter N. Horton, Simon J. Coles, Mathieu Linares, David Beljonne, Jean-Valère Naubron, Jonas Conradt, Heinz Kalt, Anna Mitraki, Athanassios G. Coutsolelos, and Teodor Silviu Balaban
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Science - Abstract
Artificial light-harvesting systems cannot self-assemble into photon-capturing structures that can reversibly switch into an inactive state. Here, the authors describe a simple and robust dipeptide construct which self-assembles to fibrils, platelets or nanospheres with varying optical properties.
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- 2016
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3. Dimension Engineering of Stimuli‐Responsive 1D Molecular Crystals into Unusual 2D and 3D Zigzag Waveguides
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Mari Annadhasan, Avulu Vinod Kumar, Prasenjit Giri, Sridatri Nandy, Manas K. Panda, K. V. Jovan Jose, and Rajadurai Chandrasekar
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General Chemistry ,General Medicine ,Catalysis - Published
- 2023
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4. Design and Synthesis of Triphenylamine Based Cyano Stilbenes for Picric Acid Sensing and Two Photon Absorption Applications
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Arivalagan Shabashini, Venkadeshkumar Ramar, Balasubramanian Karthikeyan, Ganesh Chandra Nandi, and Manas K. Panda
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chemistry.chemical_compound ,Materials science ,chemistry ,Solvatochromism ,Picric acid ,General Chemistry ,Photochemistry ,Triphenylamine ,Two-photon absorption - Published
- 2021
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5. Light-fueled rapid macroscopic motion of a green fluorescent organic crystal
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Dibyendu Dey, Manas K. Panda, Souvik Garani, Prasenjit Giri, Abhrojyoti Mazumder, and Anju Raveendran
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Diffraction ,Materials science ,business.industry ,Bent molecular geometry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Fluorescence ,Cycloaddition ,0104 chemical sciences ,Crystal ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,General Materials Science ,Reversing ,Deformation (engineering) ,0210 nano-technology ,business ,Derivative (chemistry) - Abstract
We report here a new green fluorescent organic crystal of an amide functionalized acrylonitrile derivative (E-ArF2) that displays various types of macroscopic response when illuminated with UV light (390 nm). The shape deformation and actuation of the E-ArF2 crystal can be controlled on-demand by shining UV-light on the specific parts of the crystal and reversing the direction of light illumination. When UV light is shone on the (001) face of a straight crystal, it rapidly bends away from the light source and can be bent to the opposite direction by reversing the illumination direction on the other face (00−1). With the aid of various analytical techniques, NMR, IR, UV-vis and X-ray diffraction, we established that the light fueled macroscopic actuation of the E-ArF2 crystal is rooted to the combined effect of E- to Z-isomerization and the [2 + 2] cycloaddition reaction in the solid state. Based on the above experimental facts, a general mechanistic model of the actuation is also proposed.
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- 2021
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6. Aggregation Induced Emission and Mechanochromic Luminescence by Cyanostilbene-Based Organic Luminophores
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Dibyendu Dey, Prasenjit Giri, Nayim Sepay, Ahmad Husain, and Manas K. Panda
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History ,Polymers and Plastics ,General Chemical Engineering ,General Physics and Astronomy ,General Chemistry ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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7. Rapid Visual Detection of Amines by Pyrylium Salts for Food Spoilage Taggant
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Dibyendu Dey, Sasidhar B. Somappa, Manas K. Panda, Varsha T. L, Chettiyan Thodi F. Salfeena, and Basavaraja D
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Biomaterials ,Taggant ,Visual detection ,integumentary system ,Chemistry ,Biochemistry (medical) ,Food spoilage ,technology, industry, and agriculture ,Biomedical Engineering ,food and beverages ,General Chemistry ,Food science - Abstract
Amines are ubiquitous in biological world, but are toxic and harmful in nature. Detection of biogenic amines that are released from spoiled seafood, meat, or dairy products is an important task to maintain the quality and safety of these packaged foods. To this endeavor, herein we report pyrylium salts that are capable of sensing various amines by rapid change of fluorescence color or intensity. In molecular level, this change of fluorescence is rooted to the formation of pyridine or analogous product that have distinct optical property. The pyrylium salts are capable of efficiently sensing amine vapors or amine solutions both in solid state and in solution state and thus demonstrating a multiphase sensing platform. Utilizing the excellent sensing property, we have employed our pyrylium compounds as spoilage indicator for food products such as fish, meat or cheese which relies on sensing biogenic amines released from these spoiled foods and provide optical response. Prominent change in visible and luminescence color was observed within 4-18 h of packaging at room temperature (∼33 °C). Considering the rapid response for biogenic amines, these molecular sensors have great potential to be utilized for food packaging industry, medical diagnostics, or other sensory devices.
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- 2020
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8. Distinct Mechanoresponsive Luminescence, Thermochromism, Vapochromism, and Chlorine Gas Sensing by a Solid-State Organic Emitter
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Anju Raveendran, A. P. Prakasham, Anirban Adak, K. S. Bejoymohandas, Tamas Panda, Balaram Mukhopadhyay, K. S. Asha, Manas K. Panda, and Supramolecular Chemistry & Catalysis
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Materials science ,General Chemical Engineering ,Cyan ,010402 general chemistry ,Photochemistry ,MECHANOCHROMIC LUMINESCENCE ,01 natural sciences ,AGGREGATION-INDUCED EMISSION ,Article ,Crystal ,lcsh:Chemistry ,Bathochromic shift ,FLUORESCENCE ,Thermochromism ,010405 organic chemistry ,INTRAMOLECULAR CHARGE-TRANSFER ,Intermolecular force ,General Chemistry ,POLYMORPHISM ,0104 chemical sciences ,lcsh:QD1-999 ,Intramolecular force ,Hypsochromic shift ,PHOTOLUMINESCENCE ,SECURITY INK ,Luminescence ,GOLD(I) ISOCYANIDE COMPLEX ,BEHAVIOR ,FILM - Abstract
In this study, we report a synthetically simple donor-acceptor (D-A)-type organic solid-state emitter 1 that displays unique fluorescence switching under mechanical stimuli. Orange and yellow emissive crystals of 1 (1O, 1Y) exhibit an unusual "back and forth" fluorescence response to mechanical force. Gentle crushing (mild pressure) of the orange or yellow emissive crystal results in hypsochromic shift to cyan emissive fragments (lambda(em) = 498-501 nm) with a large wavelength shift Delta lambda(em) = -71 to -96 nm, while further grinding results in bathochromic swing to green emissive powder lambda(em) = 540-550 nm, Delta lambda(em) = + 40 to 58 nm. Single-crystal X-ray diffraction study reveals that molecules are packed by weak interactions, such as C-H center dot center dot center dot pi, C-H center dot center dot center dot N, and C-H center dot center dot center dot F, which facilitate intermolecular charge transfer in the crystal. With the aid of structural, spectroscopic, and morphological studies, we established the interplay between intermolecular and intramolecular charge-transfer interaction that is responsible for this elusive mechanochromic luminescence. Moreover, we have also demonstrated the application of this organic material for chlorine gas sensing in solid state.
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- 2018
9. Enhancement of the photovoltaic performance in D 3 A porphyrin-based DSCs by incorporating an electron withdrawing triazole spacer
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Manas K. Panda, Asterios Charisiadis, Suraj Soman, Vasilis Nikolaou, Sourava C. Pradhan, Sofia Chalkiadaki, Ioannis Alexandropoulos, and Athanassios G. Coutsolelos
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Chemistry ,Triazole ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,Ring (chemistry) ,Photochemistry ,01 natural sciences ,Porphyrin ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Electron transfer ,Materials Chemistry ,Click chemistry ,Polar effect ,Molecular orbital ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
In this study, we report the preparation of two novel zinc-porphyrin derivatives (ZnP-3DoH-click-CNCOOH and ZnP-3DoH-click-COOH) and two reference compounds (ZnP-3DoH-CNCOOH and ZnP-3DoH-COOH) as sensitizers in dye-sensitized solar cells (DSCs). The photo-physical and electrochemical measurements along with the computational studies suggest that the four synthesized porphyrin derivatives exhibit appropriate light absorption characteristics as well as suitable molecular orbital levels for their use as sensitizers in DSCs. All the modified zinc-porphyrin complexes bear hexyloxy chains at the ortho-positions of their three phenyl rings and contain either a carboxylic or a cyanoacrylic acid as anchoring group. In the zinc-porphyrin derivatives ZnP-3DoH-click-CNCOOH and ZnP-3DoH-click-COOH, a spacer with an electron withdrawing unit was incorporated between the porphyrin ring and each anchoring group. More specifically, the triazole ring was used as a spacer since it is considered to be a highly efficient electron transfer bridge. In addition, the pentafluoro-phenyl ring was selected due to its strong electron withdrawing ability in both final derivatives (ZnP-3DoH-click-CNCOOH and ZnP-3DoH-click-COOH). Following this strategy, fourfold and eightfold increase of the device performance was observed regarding ZnP-3DoH-click-CNCOOH and ZnP-3DoH-click-COOH, respectively, when compared to the efficiencies achieved with the reference compounds (ZnP-3DoH-COOH and ZnP-3DoH-CNCOOH). A more detailed interpretation of the charge dynamics in these devices was carried out using charge extraction (CE) and open-circuit voltage decay (OCVD) measurements.
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- 2018
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10. Polymorphism in Sn(IV)-Tetrapyridyl Porphyrins with a Halogenated Axial Ligand: Structural, Photophysical, and Morphological Study
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Jyoti Rani, Arvind Chaudhary, Manas K. Panda, Anju Raveendran, Ranjan Patra, and Sushila
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chemistry.chemical_classification ,010405 organic chemistry ,Ligand ,Intermolecular force ,Supramolecular chemistry ,Structural formula ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Porphyrin ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallography ,chemistry ,Polymorphism (materials science) ,Non-covalent interactions ,Molecule ,General Materials Science - Abstract
In this study, we report the first example of polymorphic Sn(IV)-tetrapyridyl porphyrins axially armed with halogen (Cl, Br)-substituted carboxyphenyl ligands (structural formula [Sn(tPyP)2+(A−)2], where A is the axial ligand = 3,5-dichloro/dibromo benzoic acid). The two polymorphs of chloro-substituted Sn(IV)-tetrapyridyl porphyrin (1α and 1β) display distinct photophysical and morphological properties in the solid state. X-ray diffraction study reveals that these polymorphs 1α and 1β greatly differ in supramolecular architecture and noncovalent interactions, which is responsible for their distinct solid-state properties. Molecules of the two polymorphs adopt different conformations of the axial carboxyphenyl ligand. Crystal packing of these polymorphs are dominated by intermolecular C–H···Npyridine, C–H···O, C–H···π, and Cl···Npyridin interactions. Theoretical study showed that the energy difference between the two polymorphs is ∼8 kcal/mol. In addition to these polymorphs, a reference compound 2 with a...
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- 2018
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11. Flexibility in a Molecular Crystal Accomplished by Structural Modulation of Carbohydrate Epimers
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Rajesh Jana, Goutam Dev Mukherjee, Manas K. Panda, Balaram Mukhopadhyay, Taro Moriwaki, Panče Naumov, Gijo Raj, and Kumar Bhaskar Pal
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Chemistry ,Hydrogen bond ,Bent molecular geometry ,Mannose ,02 engineering and technology ,General Chemistry ,Carbohydrate ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Crystal ,chemistry.chemical_compound ,Crystallography ,Plastic bending ,Galactose ,Molecule ,General Materials Science ,0210 nano-technology - Abstract
Plastic bending of organic crystals is a well-known, yet mechanistically poorly understood phenomenon. On three structurally related epimers, derivatives of galactose, glucose, and mannose, it is demonstrated here that small changes in the molecular structure can have a profound effect on the mechanical properties. While the galactose derivative affords crystals which can be easily bent, the crystals of the derivatives of glucose and mannose are brittle and do not bend. Structural, microscopic, and mechanical evidence is provided showing that hydrogen bonding of water molecules is the key element for sliding over the slip planes in the crystal and accounts for the plastic bending.
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- 2017
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12. Probing Structural Perturbation in a Bent Molecular Crystal with Synchrotron Infrared Microspectroscopy and Periodic Density Functional Theory Calculations
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Panče Naumov, Manas K. Panda, Taro Moriwaki, and Ljupčo Pejov
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Diffraction ,010405 organic chemistry ,Chemistry ,Infrared ,Bent molecular geometry ,Infrared spectroscopy ,Synchrotron radiation ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Molecular physics ,Catalysis ,Synchrotron ,0104 chemical sciences ,law.invention ,Crystallography ,Colloid and Surface Chemistry ,law ,Lattice (order) ,Single crystal - Abstract
The range of unit cell orientations generated at the kink of a bent single crystal poses unsurmountable challenges with diffraction analysis and limits the insight into the molecular-scale mechanism of bending. On a plastically bent crystal of hexachlorobenzene, it is demonstrated here that spatially resolved microfocus infrared spectroscopy using synchrotron radiation can be applied in conjunction with periodic density functional theory calculations to predict spectral changes or to extract information on structural changes that occur as a consequence of bending. The approach reproduces well the observed trends, such as the wall effects, and provides estimations of the vibrational shifts, unit cell deformations, and intramolecular parameters. Generally, expansion of the lattice induces red-shift while compression induces larger blue-shift of the characteristic ν(C–C) and ν(C–Cl) modes. Uniform or non-uniform expansion or contraction of the unit cell of 0.1 A results in shifts of several cm–1, whereas def...
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- 2017
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13. Crystals on the move: mechanical effects in dynamic solids
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Patrick Commins, Israel Desta, Panče Naumov, Manas K. Panda, and Durga Prasad Karothu
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Work (thermodynamics) ,Phase transition ,010405 organic chemistry ,Chemistry ,Metals and Alloys ,Elastic energy ,Control reconfiguration ,Nanotechnology ,General Chemistry ,Kinematics ,010402 general chemistry ,Kinetic energy ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Momentum ,Chemical physics ,Materials Chemistry ,Ceramics and Composites ,Deformation (engineering) - Abstract
When exposed to external stimuli such as heat or light, certain single crystals can acquire momentum and undergo motion. On a molecular scale, the motility of such dynamic single crystals is triggered by a phase transition or chemical reaction without gaseous products, and macroscopically manifests as either slow (reversible or irreversible) deformation, or as rapid, almost instantaneous propulsion of the crystals that is oftentimes accompanied by disintegration. While the elastic energy of the slow reconfiguration processes such as bending, twisting and coiling can be utilized for actuation of other objects, the fast disintegrative processes could be exploited to initiate pressure-sensitive applications. This short review intends to summarize recent developments in the growing research on dynamic crystals, especially aspects of the mechanism of rapid motion of thermosalient and photosalient (leaping) crystals. The collective evidence indicates that these solids are organic-based analogues of the inorganic martensitic materials. While qualitative explanation of the molecular processes that lead to the related dynamic phenomena can be provided, quantification of their kinematics, estimation of the useful work that can be extracted, and prediction of their occurrence are yet to be established. Harnessing the potential of these materials to rapidly and efficiently perform the fundamentally important process of transduction of heat or light into kinetic energy appears as a prospective basis for their application in motion gears and devices.
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- 2016
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14. Mechanically Responsive Molecular Crystals
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Panče Naumov, Manas K. Panda, S.A. Chizhik, Elena V. Boldyreva, and Naba K. Nath
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Chemistry ,Nanotechnology ,General Chemistry - Published
- 2015
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15. High contrast mechanochromic and thermochromic luminescence switching by a deep red emitting organic crystal
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Manas K. Panda, Nayana Ravi, P. Asha, A. P. Prakasham, and Supramolecular Chemistry & Catalysis
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Diffraction ,Materials science ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,COLOR ,General Materials Science ,FLUORESCENCE ,Thermochromism ,DERIVATIVES ,Organic crystal ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Fluorescence ,0104 chemical sciences ,Amorphous solid ,SOLID-STATE ,Wavelength ,DENSITY ,COMPLEXES ,Hypsochromic shift ,EMISSION ,0210 nano-technology ,Luminescence ,BEHAVIOR ,FILM - Abstract
In this study, we report a deep red emissive organic crystal that displays high contrast fluorescence switching under mechanical and thermal stimulation. Upon mechanical grinding, the pristine red emissive crystals of 1R (λem = 667 nm) transformed into green emissive crystalline powder (λem = 550 nm) with a remarkable hypsochromic shift of wavelength, Δλ = 117 nm. The melting of 1R leads to a green emissive amorphous solid (λem = 555 nm) with a wavelength shift of Δλ = 112 nm. Upon fuming with different solvents, the amorphous melt solid transforms into different polymorphs having distinct emission characters. The structural relationship between different emissive states is investigated with the aid of X-ray diffraction and other spectroscopic studies, which clearly demonstrate the roles of ordered molecular packing and intermolecular interaction in determining their diverse optical response.
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- 2018
16. Acoustic Emission from Organic Martensites
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Martin Etter, Manas K. Panda, Robert E. Dinnebier, and Panče Naumov
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Materials science ,Elastic energy ,Context (language use) ,02 engineering and technology ,General Chemistry ,General Medicine ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,Thermal expansion ,0104 chemical sciences ,Crystal ,Crystallography ,Molecular solid ,Acoustic emission ,Chemical physics ,Martensite ,ddc:540 ,0210 nano-technology ,Metallic bonding - Abstract
Angewandte Chemie / International edition 56(28), 8104 - 8109 (2017). doi:10.1002/anie.201702359, In salient effects, still crystals of solids that switch between phases acquire a momentum and are autonomously propelled because of rapid release of elastic energy accrued during a latent structural transition induced by heat, light, or mechanical stimulation. When mechanical reconfiguration is induced by change of temperature in thermosalient crystals, bursts of detectable acoustic waves are generated prior to self-actuation. These observations provide compelling evidence that the thermosalient transitions in organic and organic-containing crystals are molecular analogues of the martensitic transitions in some metals, and metal alloys such as steel and shape-memory alloys. Within a broader context, these results reveal that, akin to metallic bonding, the intermolecular interactions in molecular solids are capable of gradual accrual and sudden release of a substantial amount of strain during anisotropic thermal expansion, followed by a rapid transformation of the crystal packing in a diffusionless, non-displacive transition., Published by Wiley, Weinheim
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- 2017
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17. Five‐Coordinate Indium(III) Porphyrins with Hydroxy and Carboxy BODIPY as Axial Ligands: Synthesis, Characterization and Photophysical Studies
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Vasilis Nikolaou, Manas K. Panda, Theodore Lazarides, Athanassios G. Coutsolelos, and Georgios Charalambidis
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Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Excited state ,Proton NMR ,Time-dependent density functional theory ,Carbon-13 NMR ,Chromophore ,BODIPY ,Photochemistry ,Electrochemistry ,Fluorescence spectroscopy - Abstract
A new series of dyads (TPP)In–O–BDP and (TPP)In–OOC–BDP comprising an indium tetraphenylporphyrin (TPP)In–Cl axially substituted with different boron dipyrrin (bodipy) chromophores are reported. Both compounds were synthesized by the reaction between (TPP)In–Cl and corresponding bodipy units in the presence of a NaH base. Two reference compounds (TPP)In–O–Ph and (TPP)In–OOC–Ph have also been synthesized in order to compare their photophysical and electrochemical properties with the final dyads. The photophysical properties of the compounds were investigated by UV/Vis and fluorescence spectroscopy studies at room temperature as well as at 77 K. Fluorescence spectra suggest weak excited state interactions between the bodipy chromophore and the indium–porphyrin unit. The electrochemical as well as the 1H NMR and 13C NMR spectroscopic data also support the formation of the dyads (TPP)In–O–BDP and (TPP)In–OOC–BDP. Furthermore, DFT and TDDFT calculations were carried out to obtain insight into the electronic properties of the dyads.
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- 2014
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18. Spatially resolved analysis of short-range structure perturbations in a plastically bent molecular crystal
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Goutam Dev Mukherjee, Nobuhiro Yasuda, Manas K. Panda, C. Malla Reddy, Panče Naumov, Taro Moriwaki, and Soumyajit Ghosh
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Diffraction ,Crystal ,Crystallography ,Brittleness ,Chemical physics ,Chemistry ,General Chemical Engineering ,Lattice (order) ,Bent molecular geometry ,Supramolecular chemistry ,General Chemistry ,Plasticity ,Anisotropy - Abstract
The exceptional mechanical flexibility observed with certain organic crystals defies the common perception of single crystals as brittle objects. Here, we describe the morphostructural consequences of plastic deformation in crystals of hexachlorobenzene that can be bent mechanically at multiple locations to 360° with retention of macroscopic integrity. This extraordinary plasticity proceeds by segregation of the bent section into flexible layers that slide on top of each other, thereby generating domains with slightly different lattice orientations. Microscopic, spectroscopic and diffraction analyses of the bent crystal showed that the preservation of crystal integrity when stress is applied on the (001) face requires sliding of layers by breaking and re-formation of halogen-halogen interactions. Application of stress on the (100) face, in the direction where π···π interactions dominate the packing, leads to immediate crystal disintegration. Within a broader perspective, this study highlights the yet unrecognized extraordinary malleability of molecular crystals with strongly anisotropic supramolecular interactions.
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- 2014
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19. Photomechanical and Photochromic Behavior of a Molecule Containing Multiple Photoactive Groups
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Mouza A. Alzaabi, Brandon M. Wahba, Nada ElAzhary, Panče Naumov, Manas K. Panda, and Jolly Jacob
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Photomechanical ,Schiff base ,photochromism ,photomechanical effects ,proton transfer ,tautomerism ,General Chemistry ,Photochemistry ,Photochromism ,Tautomer ,Proton transfer ,chemistry.chemical_compound ,chemistry ,Molecule ,Tautomerism - Abstract
Panda, M. K., ElAzhary, N., Alzaabi, M. A., Wahba, B. M., Jacob, J., & Naumov, P. (2014). Photomechanical and photochromic behavior of a molecule containing multiple photoactive groups. Croatica Chemica Acta, 87(4), 475-479., Photomechanical and photochromic activities are reported for single crystals of a new ultiresponsive material 2,4-di-tert-butyl-6-((E)-((4-((E)- phenyldiazenyl)phenyl)imino)methyl) phenol (Azim1), with two photoactive groups that can undergo photoisomerization (azo and imine), and an orthohydroxy group that is capable of proton transfer. Upon irradiation with UV light, platy and needle-shaped crystals of Azim-1 rapidly bend towards the light source and return to their initial shape as soon as the irradiation is terminated. Upon prolonged exposure to UV light, the crystals change their color from yellow to red. The crystal structure of non-irradiated Azim-1 is reported, and the mechanisms of the photomechanical and photochromic responses are discussed.
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- 2014
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20. Multifunctional and robust covalent organic framework–nanoparticle hybrids
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Manas K. Panda, David Díaz Díaz, S. M. Shivaprasad, Rahul Banerjee, Pradip Pachfule, and Sharath Kandambeth
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Solid-state chemistry ,Materials science ,Renewable Energy, Sustainability and the Environment ,Reducing agent ,Sonogashira coupling ,Nanoparticle ,General Chemistry ,Coupling reaction ,Catalysis ,Chemical engineering ,Organic chemistry ,General Materials Science ,Hybrid material ,Covalent organic framework - Abstract
Highly dispersed Pd(0) nanoparticles were successfully immobilized into a stable, crystalline and porous covalent organic framework (COF), TpPa-1, by a solution infiltration method using NABH4 as a reducing agent. High resolution and dark field TEM images confirmed the uniform loading of the Pd(0) nanoparticles into the TpPa-1 matrix without aggregation. This hybrid material exhibited excellent catalytic activity towards the Cu free Sonogashira, Heck and sequential one pot Heck–Sonogashira cross-coupling reactions under basic conditions, and with superior performance compared to commercially available Pd supported on activated charcoal (i.e., 1, 5 and 10 wt%). Additionally, the precursor Pd(II)-doped COF also displayed competitive catalytic activity for the intramolecular oxidative biaryl synthesis under acidic conditions. Both catalysts were found to be highly stable under the reaction conditions showing negligible metal leaching, non-sintering behavior, and good recyclability. To the best of our knowledge, the organic support used in this work, TpPa-1, constitutes the first COF matrix that can hold both Pd(0) nanoparticles and Pd(II) complex without aggregation for catalytic purposes under both highly acidic and basic conditions.
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- 2014
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21. Crystallographic Snapshots of the Interplay between Reactive Guest and Host Molecules in a Porous Coordination Polymer: Stereochemical Coupling and Feedback Mechanism of Three Photoactive Centers Triggered by UV-Induced Isomerization, Dimerization, and Polymerization Reactions
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Panče Naumov, Manas K. Panda, Xi Ling Deng, Boon K. Teo, Shi Yao Yang, Rui Fang Jin, Rong-Bin Huang, and Lan-Sun Zheng
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Chemistry ,Coordination polymer ,Radical polymerization ,General Chemistry ,Photochemistry ,Biochemistry ,Catalysis ,Cycloaddition ,chemistry.chemical_compound ,Crystallography ,Colloid and Surface Chemistry ,Photopolymer ,Polymerization ,X-ray crystallography ,Molecule ,Isomerization - Abstract
We carried out photopolymerization by [2 + 2] dimerization of a photoreactive guest molecule in the channels of a photoreactive porous coordination polymer. The photoreactions of the guest and two host ligands were monitored by single-crystal X-ray crystallography, providing snapshots of the interplay between the reactive centers. By correlating the structures of these three photocenters, a strong synergism was discovered among three reaction (quasi)equilibria and three types of photochemical reactions (isomerization, dimerization, and polymerization). This result indicates a strong coupling and feedback mechanism among the photocenters moderated by the coordination backbone.
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- 2013
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22. Efficient Sensitization of Dye-Sensitized Solar Cells by Novel Triazine-Bridged Porphyrin–Porphyrin Dyads
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Panagiotis A. Angaridis, M.S. Roy, Manas K. Panda, Galateia E. Zervaki, Athanassios G. Coutsolelos, Ganesh D. Sharma, and Emmanouel Chrissos
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Models, Molecular ,Porphyrins ,Metalloporphyrins ,Cyanuric chloride ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,Electrochemistry ,01 natural sciences ,7. Clean energy ,Inorganic Chemistry ,chemistry.chemical_compound ,Electric Power Supplies ,Solar Energy ,Moiety ,Physical and Theoretical Chemistry ,Coloring Agents ,Amination ,Triazine ,Triazines ,Electrochemical Techniques ,021001 nanoscience & nanotechnology ,Porphyrin ,0104 chemical sciences ,Zinc ,Dye-sensitized solar cell ,chemistry ,Covalent bond ,Quantum Theory ,0210 nano-technology - Abstract
Two novel porphyrin-porphyrin dyads, the symmetrical Zn[Porph]-Zn[Porph] (2) and unsymmetrical Zn[Porph]-H2[Porph] (4), where Zn[Porph] and H2[Porph] are the metalated and free-base forms of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin, respectively, in which two porphyrin units are covalently bridged by 1,3,5-triazine, have been synthesized via the stepwise amination of cyanuric chloride. The dyads are also functionalized by a terminal carboxylic acid group of a glycine moiety attached to the triazine group. Photophysical measurements of 2 and 4 showed broaden and strengthened absorptions in their visible spectra, while electrochemistry experiments and density functional theory calculations revealed negligible interaction between the two porphyrin units in their ground states but appropriate frontier orbital energy levels for use in dye-sensitized solar cells (DSSCs). The 2- and 4-based solar cells have been fabricated and found to exhibit power conversion efficiencies (PCEs) of 3.61% and 4.46%, respectively (under an illumination intensity of 100 mW/cm(2) with TiO2 films of 10 μm thickness). The higher PCE value of the 4-based DSSC, as revealed by photovoltaic measurements (J-V curves) and incident photon-to-current conversion efficiency (IPCE) spectra of the two cells, is attributed to its enhanced short-circuit current (J(sc)) under illumination, high open-circuit voltage (V(oc)), and fill factor (FF) values. Electrochemical impedance spectra demonstrated shorter electron-transport time (τd), longer electron lifetime (τe), and high charge recombination resistance for the 4-based cell, as well as larger dye loading onto TiO2.
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- 2013
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23. Synthesis, Characterization and Electronic Properties of trans ‐[4‐(Alkoxycarbonyl)phenyl]porphyrin‐[Ru II (bpy) 3 ] 2 Complexes or Boron–Dipyrrin Conjugates as Panchromatic Sensitizers for DSSCs
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Kalliopi Ladomenou, Manas K. Panda, Theodore Lazarides, Christina Stangel, Athanassios G. Coutsolelos, and Georgios Charalambidis
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010405 organic chemistry ,chemistry.chemical_element ,Chromophore ,010402 general chemistry ,Triple bond ,Ring (chemistry) ,Photochemistry ,01 natural sciences ,Porphyrin ,0104 chemical sciences ,3. Good health ,Ruthenium ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Molecule ,Peptide bond ,Boron - Abstract
Two porphyrin-based dyes were synthesized that incorporate two additional chromophores to absorb in a wider UV/Vis region. In the first dye, a porphyrin ring is linked through an amide bond to two [Ru(bpy)3]2+ units, forming a symmetric [Ru(bpy)3]-porphyrin-[Ru(bpy)3] {Por(COOH)2[Ru(bpy)3]2} system. The second porphyrin is trans substituted through a triple bond to the meso position with two boron dipyrrin (BDP) molecules {Por(COOH)2(BDP)2}. Both porphyrins bear two carboxylic groups capable of binding onto a TiO2 surface, with potential applications in dye-sensitized solar cells (DSSCs). The title dyes were characterized by means of 1H and 13C NMR spectroscopy, elemental analysis, MALDI-TOF, UV/Vis absorption and emission studies.
- Published
- 2013
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24. Cyclometallated iridium complexes inducing paraptotic cell death like natural products: synthesis, structure and mechanistic aspects
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Umasankar De, Paltan Laha, Niranjan Dehury, Hyung Sik Kim, Srikanta Patra, Suman Kumar Tripathy, and Manas K. Panda
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Programmed cell death ,Cytoplasm ,Poly ADP ribose polymerase ,Apoptosis ,010402 general chemistry ,Iridium ,01 natural sciences ,Inorganic Chemistry ,DU145 ,Coordination Complexes ,Cell Line, Tumor ,LNCaP ,Humans ,Caspase-9 ,Biological Products ,biology ,010405 organic chemistry ,Chemistry ,Endoplasmic reticulum ,0104 chemical sciences ,Cell biology ,Biochemistry ,Pyrazines ,Cancer cell ,Vacuoles ,biology.protein ,Mitogen-Activated Protein Kinases ,Tumor Suppressor Protein p53 ,Reactive Oxygen Species ,Transcription Factor CHOP - Abstract
Six mononuclear Ir complexes (1–6) using polypyridyl-pyrazine based ligands (L1 and L2) and {[cp*IrCl(μ-Cl)]2 and [(ppy)2Ir(μ-Cl)]2} precursors have been synthesised and characterised. Complexes 1–5 have shown potent anticancer activity against various human cancer cell lines (MCF-7, LNCap, Ishikawa, DU145, PC3 and SKOV3) while complex 6 is found to be inactive. Flow cytometry studies have established that cellular accumulation of the complexes lies in the order 2 > 1 > 5 > 4 > 3 > 6 which is in accordance with their observed cytotoxicity. No changes in the expression of the proteins like PARP, caspase 9 and beclin-1, Atg12 discard apoptosis and autophagy, respectively. Overexpression of CHOP, activation of MAPKs (P38, JNK, and ERK) and massive cytoplasmic vacuolisation collectively suggest a paraptotic mode of cell death induced by proteasomal dysfunction as well as endoplasmic reticulum and mitochondrial stress. An intimate relationship between p53, ROS production and extent of cell death has also been established using p53 wild, null and mutant type cancer cells.
- Published
- 2016
25. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals
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Fabio Borbone, Panče Naumov, Roberto Centore, Angela Tuzi, Mauro Causà, Manas K. Panda, Panda, Manas K, Centore, Roberto, Causa', Mauro, Tuzi, Angela, Borbone, Fabio, and Naumov, Panče
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Phase transition ,Work (thermodynamics) ,Multidisciplinary ,Materials science ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Thermal expansion ,Article ,0104 chemical sciences ,Crystal ,Negative thermal expansion ,Chemical physics ,Thermal ,0210 nano-technology ,Anisotropy ,Molecular materials - Abstract
The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10−6 K−1, αb = 238.8 × 10−6 K−1 and αc = −290.0 × 10−6 K−1, the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously.
- Published
- 2016
26. Electron vs Energy Transfer in Arrays Featuring Two Bodipy Chromophores Axially Bound to a Sn(IV) Porphyrin via a Phenolate or Benzoate Bridge
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Theodore Lazarides, Susanne Kuhri, Manas K. Panda, Dirk M. Guldi, Athanassios G. Coutsolelos, and Georgios Charalambidis
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Absorption spectroscopy ,010405 organic chemistry ,Chromophore ,010402 general chemistry ,Photochemistry ,01 natural sciences ,7. Clean energy ,Porphyrin ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Electron transfer ,chemistry ,Excited state ,Singlet state ,Physical and Theoretical Chemistry ,BODIPY ,Ground state - Abstract
In this report we describe the synthesis of multichromophore arrays consisting of two Bodipy units axially bound to a Sn(IV) porphyrin center either via a phenolate (3) or via a carboxylate (6) functionality. Absorption spectra and electrochemical studies show that the Bodipy and porphyrin chromophores interact weakly in the ground state. However, steady-state emission and excitation spectra at room temperature reveal that fluorescence from both the Bodipy and the porphyrin of 3 are strongly quenched suggesting that, in the excited state, energy and/or electron transfer might occur. Indeed, as transient absorption experiments show, selective excitation of Bodipy in 3 results in a rapid decay (τ ≈ 2 ps) of the Bodipy-based singlet excited state and a concomitant rise of a charge-separated state evolving from the porphyrin-based singlet excited state. In contrast, room-temperature emission studies on 6 show strong quenching of the Bodipy-based fluorescence leading to sensitized emission from the porphyrin moiety due to a transduction of the singlet excited state energy from Bodipy to the porphyrin. Emission experiments at 77 K in frozen toluene reveal that the room-temperature electron transfer pathway observed in 3 is suppressed. Instead, Bodipy excitation in 3 and 6 results in population of the first singlet excited state of the porphyrin chromophore. Subsequently, intersystem crossing leads to the porphyrin-based triplet excited state.
- Published
- 2012
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27. Mimicking the Intradiol Catechol Cleavage Activity of Catechol Dioxygenase by High-Spin Iron(III) Complexes of a New Class of a Facially Bound [N2O] Ligand
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Prasenjit Ghosh, Alex John, Mobin M. Shaikh, and Manas K. Panda
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Models, Molecular ,Stereochemistry ,Iron ,Kinetics ,Catechols ,Molecular Conformation ,Tridentate Ligands ,Ligands ,Cleavage (embryo) ,Catechol 2,3-Dioxygenase ,Functional Models ,Inorganic Chemistry ,chemistry.chemical_compound ,Substrate Complex ,X-Ray Diffraction ,Crystal-Structures ,Organic chemistry ,Physical and Theoretical Chemistry ,Protocatechuate 3,4-Dioxygenase ,3n Ligands ,chemistry.chemical_classification ,Catechol ,biology ,Ligand ,Electron Spin Resonance Spectroscopy ,Regioselectivity ,Cleaving Dioxygenases ,Nonheme Iron Enzymes ,Catalytic-Activity ,Oxygen ,Enzyme ,chemistry ,biology.protein ,Thermodynamics ,Nitrogen Oxides ,Binding-Site ,Catechol dioxygenase ,Acetamide - Abstract
A series of high-spin iron(III) complexes, {N-R-2-[(pyridin-2-ylmethyl)amino]acetamide}FeCl(3) [R = mesityl (1b), 2,6-Et(2)C(6)H(3) (2b), and 2,6-i-Pr(2)C(6)H(3) (3b)], that functionally emulate the intradiol catechol dioxygenase enzyme are reported. In particular, these enzyme mimics, 1b, 2b, and 3b, which utilized molecular oxygen in carrying out the intradiol catechol cleavage of 3,5-di-tert-butylcatechol with high regioselectivity. (ca. 81-85%) at room temperature under ambient conditions, were designed by employing a new class of a facially bound [N(2)O] ligand, namely, N-R-2-[(pyridin-2-ylmethyl)amino]acetamide [R = mesityl (1a), 2,6-Et(2)C(6)H(3) (2a), and 2,6-i-Pr(2)C(6)H(3) (3a)]. The density functional theory studies revealed that the intradiol catechol cleavage reaction proceeded by an iron(III) peroxo intermediate that underwent 1,2-Criegee rearrangement to yield the intradiol catechol cleaved products analogous to the native enzyme.
- Published
- 2008
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28. A switchable self-assembling and disassembling chiral system based on a porphyrin-substituted phenylalanine-phenylalanine motif
- Author
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Tobias Jochum, Georgios Charalambidis, Mathieu Linares, David Beljonne, Jonas Conradt, Anna Mitraki, Teodor Silviu Balaban, Heinz Kalt, Peter N. Horton, Simon J. Coles, Manas K. Panda, Jean-Valère Naubron, Stephen Doyle, David A. Moss, Athanassios G. Coutsolelos, Evangelos Georgilis, Annie K. Powell, Christopher E. Anson, Laboratory of Bioinorganic Chemistry, Department of Chemistry [Heraklion], University of Crete [Heraklion] (UOC)-University of Crete [Heraklion] (UOC), Institute of Electronic Structure & Laser, Foundation for Research and Technology - Hellas (FORTH), Department of Materials Science and Technology, University of Crete [Heraklion] (UOC), Karlsruhe Institute of Technology (KIT), National Crystallography Service (NCS), University of Southampton, Department of Physics, Chemistry and Biology [Linköping] (IFM), Linköping University (LIU), Univ Mons, Lab Chem Novel Mat, Belgium, Université de Mons (UMons), Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Crete, European Project: 229927,EC:FP7:REGPOT,FP7-REGPOT-2008-1,BIOSOLENUTI(2009), European Project: 0317304(2003), European Project: 256672,EC:FP7:ENERGY,FP7-ENERGY-2010-FET,PEPDIODE(2011), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)
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Materials science ,Science ,Atom and Molecular Physics and Optics ,General Physics and Astronomy ,Phenylalanine ,010402 general chemistry ,Fibril ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Article ,chemistry.chemical_compound ,[CHIM]Chemical Sciences ,Multidisciplinary ,010405 organic chemistry ,Structure elucidation ,General Chemistry ,Self-assembly ,Fluorescence ,Porphyrin ,0104 chemical sciences ,3. Good health ,Dilution ,Solvent ,Crystallography ,chemistry ,Atom- och molekylfysik och optik ,Single crystal - Abstract
Artificial light-harvesting systems have until now not been able to self-assemble into structures with a large photon capture cross-section that upon a stimulus reversibly can switch into an inactive state. Here we describe a simple and robust FLFL-dipeptide construct to which a meso-tetraphenylporphyrin has been appended and which self-assembles to fibrils, platelets or nanospheres depending on the solvent composition. The fibrils, functioning as quenched antennas, give intense excitonic couplets in the electronic circular dichroism spectra which are mirror imaged if the unnatural FDFD-analogue is used. By slightly increasing the solvent polarity, these light-harvesting fibres disassemble to spherical structures with silent electronic circular dichroism spectra but which fluoresce. Upon further dilution with the nonpolar solvent, the intense Cotton effects are recovered, thus proving a reversible switching. A single crystal X-ray structure shows a head-to-head arrangement of porphyrins that explains both their excitonic coupling and quenched fluorescence., Artificial light-harvesting systems cannot self-assemble into photon-capturing structures that can reversibly switch into an inactive state. Here, the authors describe a simple and robust dipeptide construct which self-assembles to fibrils, platelets or nanospheres with varying optical properties.
- Published
- 2016
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29. Perpetually self-propelling chiral single crystals
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Tomče Runčevski, Manas K. Panda, Panče Naumov, Robert E. Dinnebier, and Ahmad Husain
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Models, Molecular ,Phase transition ,Structural phase ,Hot Temperature ,Strain (chemistry) ,Chemistry ,Molecular Conformation ,Hydrogen Bonding ,Stereoisomerism ,General Chemistry ,Biochemistry ,Catalysis ,Thermal expansion ,Elasticity ,Phase Transition ,Pyrrolidonecarboxylic Acid ,Crystal ,Crystallography ,Motion ,Colloid and Surface Chemistry ,Negative thermal expansion ,Pseudoelasticity - Abstract
When heated, single crystals of enantiomerically pure D- and L-pyroglutamic acid (PGA) are capable of recurring self-actuation due to rapid release of latent strain during a structural phase transition, while the racemate is mechanically inactive. Contrary to other thermosalient materials, where the effect is accompanied by crystal explosion due to ejection of debris or splintering, the chiral PGA crystals respond to internal strain with unprecedented robustness and can be actuated repeatedly without deterioration. It is demonstrated that this superelasticity is attained due to the low-dimensional hydrogen-bonding network which effectively accrues internal strain to elicit propulsion solely by elastic deformation without disintegration. One of the two polymorphs (β) associated with the thermosalient phase transition undergoes biaxial negative thermal expansion (αa = -54.8(8) × 10(-6) K(-1), αc = -3.62(8) × 10(-6) K(-1)) and exceptionally large uniaxial thermal expansion (αb = 303(1) × 10(-6) K(-1)). This second example of a thermosalient solid with anomalous expansion indicates that the thermosalient effect can be expected for first-order phase transitions in soft crystals devoid of an extended 3D hydrogen-bonding network that undergo strongly anisotropic thermal expansion around the phase transition.
- Published
- 2015
30. Colossal positive and negative thermal expansion and thermosalient effect in a pentamorphic organometallic martensite
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Manas K. Panda, Panče Naumov, Tomče Runčevski, Alexei A. Belik, Robert E. Dinnebier, Naba K. Nath, and Subash Chandra Sahoo
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Phase transition ,Multidisciplinary ,Materials science ,Condensed matter physics ,Plane (geometry) ,General Physics and Astronomy ,chemistry.chemical_element ,General Chemistry ,Crystal structure ,General Biochemistry, Genetics and Molecular Biology ,Crystal ,Molecular solid ,chemistry ,Negative thermal expansion ,Martensite ,Palladium - Abstract
The thermosalient effect is an extremely rare propensity of certain crystalline solids for self-actuation by elastic deformation or by a ballistic event. Here we present direct evidence for the driving force behind this impressive crystal motility. Crystals of a prototypical thermosalient material, (phenylazophenyl)palladium hexafluoroacetylacetonate, can switch between five crystal structures (α-ε) that are related by four phase transitions including one thermosalient transition (α↔γ). The mechanical effect is driven by a uniaxial negative expansion that is compensated by unusually large positive axial expansion (260 × 10(-6) K(-1)) with volumetric expansion coefficients (≈250 × 10(-6) K(-1)) that are among the highest values reported in molecular solids thus far. The habit plane advances at ~10(4) times the rate observed with non-thermosalient transitions. This rapid expansion of the crystal following the phase switching is the driving force for occurrence of the thermosalient effect.
- Published
- 2014
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31. Enhancement of chemical stability and crystallinity in porphyrin-containing covalent organic frameworks by intramolecular hydrogen bonds
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Sharath Kandambeth, Digambar Balaji Shinde, Rahul Banerjee, Binit Lukose, Manas K. Panda, and Thomas Heine
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010405 organic chemistry ,Hydrogen bond ,Chemistry ,Inorganic chemistry ,Dynamic covalent chemistry ,General Medicine ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Tautomer ,Porphyrin ,eye diseases ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallinity ,Chemical engineering ,Covalent bond ,Intramolecular force ,Chemical stability ,sense organs - Abstract
A strong bond: A strategy based on intramolecular hydrogen-binding interactions in 2D covalent organic frameworks (COFs) is shown to improve the crystallinity, porosity, and chemical stability of the material. The concept is validated by removing the hydrogen-bonding interaction in the methoxy analog which showed a lower stability and crystallinity.
- Published
- 2013
32. Biomimetic crystalline actuators: structure-kinematic aspects of the self-actuation and motility of thermosalient crystals
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Panče Naumov, Manas K. Panda, Naba K. Nath, and Subash Chandra Sahoo
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Hot Temperature ,Chemistry ,Nanotechnology ,General Chemistry ,Kinematics ,Biochemistry ,Catalysis ,Characterization (materials science) ,Biomechanical Phenomena ,Motion ,Colloid and Surface Chemistry ,Homogeneous ,Biomimetics ,Actuator ,Mechanical Phenomena - Abstract
While self-actuation and motility are habitual for humans and nonsessile animals, they are hardly intuitive for simple, lifeless, homogeneous objects. Among mechanically responsive materials, the few accidentally discovered examples of crystals that when heated suddenly jump, propelling themselves to distances that can reach thousands of times their own size in less than 1 ms, provide the most impressive display of the conversion of heat into mechanical work. Such thermosalient crystals are biomimetic, nonpolymeric self-actuators par excellence. Yet, due to the exclusivity and incongruity of the phenomenon, as well as because of the unavailability of ready analytical methodology for its characterization, the reasons behind this colossal self-actuation remain unexplained. Aimed at unraveling the mechanistic aspects of the related processes, herein we establish the first systematic assessment of the interplay among the thermodynamic, kinematic, structural, and macroscopic factors driving the thermosalient phenomenon. The collective results are consistent with a latent but very rapid anisotropic unit cell deformation in a two-stage process that ultimately results in crystal explosion, separation of debris, or crystal reshaping. The structural perturbations point to a mechanism similar to phase transitions of the martensitic family.
- Published
- 2013
33. Meso-substituted Porphyrin Derivatives via Palladium-Catalyzed Amination Showing Wide Range Visible Absorption: Synthesis and Photophysical Studies
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Manas K. Panda, Theodore Lazarides, Kalliopi Ladomenou, Athanassios G. Coutsolelos, Georgios Charalambidis, and Dimitra Daphnomili
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Models, Molecular ,Porphyrins ,Molecular Conformation ,Color ,chemistry.chemical_element ,Chemistry Techniques, Synthetic ,010402 general chemistry ,Photochemistry ,7. Clean energy ,01 natural sciences ,Catalysis ,Coupling reaction ,Absorption ,photoinduced electron-transfer ,Inorganic Chemistry ,chemistry.chemical_compound ,cross-coupling reactions ,Electrochemistry ,medicine ,Physical and Theoretical Chemistry ,Amination ,chiral porphyrins ,010405 organic chemistry ,sensitized solar-cells ,Triad (anatomy) ,Chromophore ,functionalized porphyrins ,substituted porphyrins ,Porphyrin ,self-organization ,0104 chemical sciences ,medicine.anatomical_structure ,chemistry ,zinc porphyrin ,efficient synthesis ,Palladium ,Visible spectrum ,crystal-structures - Abstract
In recent years, there has been a growing interest in the design and synthesis of chromophores, which absorb in a wide region of the visible spectrum, as these constitute promising candidates for use as sensitizers in various solar energy conversion schemes. In this work, a palladium-catalyzed coupling reaction was employed in the synthesis of molecular triads in which two porphyrin or boron dipyrrin (BDP) chromophores are linked to the meso positions of a central Zn porphyrin (PZn) ring via an amino group. In the resulting conjugates, which strongly absorb over most of the visible region, the electronic properties of the constituent chromophores are largely retained while detailed emission experiments reveal the energy transfer pathways that occur in each triad. Inorg Chem
- Published
- 2012
34. Functional mimics of catechol oxidase by mononuclear copper complexes of sterically demanding [NNO] ligands
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Manas K. Panda, Prasenjit Ghosh, Mobin M. Shaikh, and Ray J. Butcher
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Steric effects ,Schiff-Base Ligands ,chemistry.chemical_element ,Density ,Purple Acid-Phosphatases ,Medicinal chemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Iron(Iii) Complexes ,Dicopper(Ii) Complexes ,Models ,Oxidation ,Materials Chemistry ,Organic chemistry ,Moiety ,Physical and Theoretical Chemistry ,Density Functional Theory ,Crystal-Structure ,Dioxygen ,Aryl ,Proteins ,Purple acid phosphatases ,Copper ,chemistry ,Catalytic cycle ,Intramolecular force ,Acetamide ,Catechol Oxidase - Abstract
Several mononuclear copper complexes 1(a-b) and 2(a-b) supported over sterically demanding [NNO] ligands namely, N-(aryl)-2-[(pyridin-2-ylmethyl) amino] acetamide [aryl = 2,6-diethylphenyl (1) and mesityl (2)], exhibit catecholase-like activity in performing the aerial oxidation of 3,5-di-t-butylcatehol (3,5-DTBC) to 3,5-di-t-butyl-catequinone (3,5-DTBQ) under ambient conditions. The 1(a-b) and 2(a-b) complexes were directly synthesized from the reaction of the respective ligands 1-2 with CuX(2)center dot nH(2)O (X = Cl, NO(3), n = 2, 3) in 55-85% yield. Mechanistic insights on the catalytic cycle as obtained by density functional theory studies for a representative complex 1a suggest that an intramolecular hydrogen transfer, from a catechol-OH moiety to a copper bound superoxo moiety, form the rate-determining step of the oxidation process, displaying an activation barrier of 18.3 kcal/mol (Delta G(double dagger)) [6.9 kcal/mol in Delta(PE + ZPE)(double dagger) scale]. (C) 2011 Elsevier B. V. All rights reserved.
- Published
- 2011
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35. Detrimental Effect of Silicon Nanoparticles on P3HT:PCBM-Based OPV Devices
- Author
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Matteo Chiesa, Samuele Lilliu, Manas K. Panda, Mejd Alsari, Yamila M. Omar, and Panče Naumov
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Materials science ,Silicon ,Polymers and Plastics ,business.industry ,Organic Chemistry ,chemistry.chemical_element ,Nanoparticle ,Condensed Matter Physics ,Polymer solar cell ,chemistry ,Materials Chemistry ,Optoelectronics ,Physical and Theoretical Chemistry ,business ,Inkjet printing - Published
- 2015
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36. Photomechanical and Photochromic Behavior of a Molecule Containing Multiple Photoactive Groups
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Manas K. Panda, Nada ElAzhary, Mouza A. Alzaabi, Brandon M. Wahba, Jolly Jacob, Panče Naumov, Manas K. Panda, Nada ElAzhary, Mouza A. Alzaabi, Brandon M. Wahba, Jolly Jacob, and Panče Naumov
- Abstract
Photomechanical and photochromic activities are reported for single crystals of a new multirespon-sive material, 2,4-di-tert-butyl-6-((E)-((4-((E)-phenyldiazenyl)phenyl)imino)methyl)phenol (Azim-1), with two photoactive groups that can undergo photoisomerization (azo and imine), and an ortho-hydroxy group that is capable of proton transfer. Upon irradiation with UV light, platy and needle-shaped crystals of Azim-1 rapidly bend towards the light source and return to their initial shape as soon as the irradiation is terminated. Upon prolonged exposure to UV light, the crystals change their color from yellow to red. The crystal structure of non-irradiated Azim-1 is reported, and the mecha-nisms of the photomechanical and photochromic responses are discussed.
- Published
- 2014
37. Single Crystal in Motion: An Insight into the Mechanism of Actuation
- Author
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Manas K. Panda and Panče Naumov
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Diffraction ,Materials science ,business.industry ,Control reconfiguration ,Synchrotron radiation ,Nanotechnology ,Condensed Matter Physics ,Smart material ,Biochemistry ,Inorganic Chemistry ,Structural Biology ,General Materials Science ,Physical and Theoretical Chemistry ,business ,Actuator ,Nanoscopic scale ,Single crystal ,Thermal energy - Abstract
Dynamic materials that can rapidly transform one form of energy into another have recently attracted attention because they could be utilized as platform for actuation from the nanoscale to the macroscale. This rapidly expanding field has brought up an increasing number of examples of oftentimes serendipitous observations of macro-, milli- and nano-sized single crystals that can hop, bend, curl or twist when exposed to light, heat or external pressure and have the capability to induce motion of other objects. Among these biomimetic crystalline actuators, the so-called thermosalient (TS) crystals, when heated or cooled, exhibit spectacular macroscopic motility as a result of fast coupling of thermal energy with mechanical actuation (Figure 1). Some of these crystals are exceptionally robust and undergo mechanical actuation for several cycles without disintegration. Achieving concurrently fast and reversible actuation of molecular crystals remains a great challenge since mechanical reconfiguration of single crystals is generally accompanied by loss of integrity (cracking, fracturing, explosion, etc.), a serious pitfall that limits their compatibility with the basic requirements for applications as dynamic modules. Despite the potential importance of these biomimetic crystalline actuators as smart materials, the detailed mechanism of actuation and shape change is not understood well. Here we report systematic investigation of the mechanism of mechanical response of these crystalline materials with the aid of single crystal X-ray diffraction, powder X-ray diffraction using synchrotron radiation, and other advanced instrumental techniques.
- Published
- 2014
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38. Mechanical Effects in Molecular Crystals – A Revival
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Elisa Nauha, Naba K. Nath, Manas K. Panda, Panče Naumov, Subash Chandra Sahoo, and Ahmad Husain
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Inorganic Chemistry ,Materials science ,Structural Biology ,Chemical physics ,General Materials Science ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Biochemistry - Abstract
"The classical perception of single crystals of molecular materials as rigid and brittle entities has downsized the research interest in mechanical effects that had been initiated and was active back in the 1980s. More recently, the modern analytical techniques for mechanical, electron-microscopic, structural, spectroscopic and kinematic characterization have contributed to accumulate compelling evidence that under certain circumstances, even some seemingly rigid single crystals can deform, bend, twist, hop, wiggle or perform other ""acrobatics"" that are atypical for non-soft matter. These examples contribute to a paradigm shift in our understanding of the elasticity of molecular crystals and also provide direct mechanistic insight into the structural perturbations at the limits of the susceptibility of ordered matter to internal and external mechanical force. As the relevance of motility and reshaping of molecular crystals is being recognized by the crystal research community as a demonstration of a very basic concept–conversion of thermal or light energy into work–a new and exciting crystal chemistry around mechanically responsive single crystals rapidly unfolds."
- Published
- 2014
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39. Thermally induced and photoinduced mechanical effects in molecular single crystals—a revival
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Manas K. Panda, Panče Naumov, Naba K. Nath, and Subash Chandra Sahoo
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Chemistry ,Crystal chemistry ,Nanotechnology ,General Chemistry ,Kinematics ,Elasticity (physics) ,Condensed Matter Physics ,Characterization (materials science) ,Crystal ,Chemical physics ,Light energy ,Research community ,General Materials Science ,Molecular materials - Abstract
The classical perception of single crystals of molecular materials as rigid and brittle entities has downsized the research interest in their mechanical effects that had been initiated and was active back in the 1980s. More recently, the modern analytical techniques for their mechanical, electron-microscopic, structural, spectroscopic and kinematic characterization have contributed to accumulate compelling evidence that under certain circumstances, even some seemingly rigid single crystals can deform, bend, twist, hop, wiggle or perform other ‘acrobatics’ that are atypical for non-soft matter. These examples contribute to a paradigm shift in our understanding of the elasticity of molecular crystals and also provide direct mechanistic insight into the structural perturbations at the limits of the susceptibility of ordered matter to internal and external mechanical forces. As the relevance of motility and reshaping of molecular crystals is being recognized by the crystal research community as a demonstration of a very basic concept—conversion of thermal or light energy into work—a new and exciting crystal chemistry around mechanically responsive single crystals rapidly unfolds.
- Published
- 2014
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40. Significant enhancement in the power conversion efficiency of porphyrin based dye sensitized solar cell by co-sensitization with metal free dye
- Author
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M.S. Roy, Ganesh D. Sharma, Athanassios G. Coutsolelos, Manas K. Panda, John A. Mikroyannidis, and E. Gad
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Zinc porphyrin ,chemistry.chemical_compound ,Dye-sensitized solar cell ,Materials science ,Metal free ,chemistry ,Renewable Energy, Sustainability and the Environment ,Energy conversion efficiency ,Co sensitization ,Photochemistry ,Porphyrin ,Dielectric spectroscopy - Abstract
A step wise approach for co-sensitization of a zinc porphyrin sensitizer (Zn-por) with symmetrical BF2–azopyrrole dye (BF2) for dye sensitized solar cells (DSSCs) has been developed. With this approach, the co-sensitized Zn-por + BF2 based DSSC shows both Jsc and Voc significantly enhanced in relation to their individual sensitized DSSCs. Upon optimization, the DSSC sensitized with Zn-por + BF2 system yields Jsc = 12.4 mA cm−2, Voc = 0.72 V, FF = 0.70, and PCE = 6.25%. This performance is superior to that of individual DSSC sensitized with Zn-por (PCE = 4.83%) and BF2 (PCE = 3.26%), respectively, under similar conditions. The broader IPCE spectra of the DSSC based on Zn-por + BF2 dye relative to other DSSCs are responsible for the higher Jsc. From the electrochemical impedance spectroscopy (EIS) data, we found that the charge recombination can be significantly retarded for co-sensitized system, relative to the Zn-por based DSSCs to account for the enhanced Voc. The PCE is further enhanced by employing decoxycholic acid (DCA) as coadsorbent. The highest PCE obtained for DSSC with Zn-por and BF2 in the presence of DCA is about 7.46%.
- Published
- 2013
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41. Controlled oxidation of organic sulfides to sulfoxides under ambient conditions by a series of titanium isopropoxide complexes using environmentally benign H2O2 as an oxidant
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Manas K. Panda, Mobin M. Shaikh, and Prasenjit Ghosh
- Subjects
Models, Molecular ,Aqueous solution ,Molecular Structure ,Thioanisole ,Substrate (chemistry) ,chemistry.chemical_element ,Stereoisomerism ,Hydrogen Peroxide ,Crystallography, X-Ray ,Oxidants ,Photochemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Catalytic cycle ,Organometallic Compounds ,Moiety ,Sulfhydryl Compounds ,Titanium isopropoxide ,Oxidation-Reduction ,Titanium - Abstract
Controlled oxidation of organic sulfides to sulfoxides under ambient conditions has been achieved by a series of titanium isopropoxide complexes that use environmentally benign H(2)O(2) as a primary oxidant. Specifically, the [N,N'-bis(2-oxo-3-R(1)-5-R(2)-phenylmethyl)-N,N'-bis(methylene-R(3))-ethylenediamine]Ti(O(i)Pr)(2) [R(1) = t-Bu, R(2) = Me, R(3) = C(7)H(5)O(2) (1b); R(1) = R(2) = t-Bu, R(3) = C(7)H(5)O(2) (2b); R(1) = R(2) = Cl, R(3) = C(7)H(5)O(2) (3b) and R(1) = R(2) = Cl, R(3) = C(6)H(5) (4b)] complexes efficiently catalyzed the sulfoxidation reactions of organic sulfides to sulfoxides at room temperature within 30 min of the reaction time using aqueous H(2)O(2) as an oxidant. A mechanistic pathway, modeled using density functional theory for a representative thioanisole substrate catalyzed by 4b, suggested that the reaction proceeds via a titanium peroxo intermediate 4c', which displays an activation barrier of 22.5 kcal mol(-1) (DeltaG(++)) for the overall catalytic cycle in undergoing an attack by the S atom of the thioanisole substrate at its sigma*-orbital of the peroxo moiety. The formation of the titanium peroxo intermediate was experimentally corroborated by a mild ionization atmospheric pressure chemical ionization (APCI) mass spectrometric technique.
- Published
- 2010
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