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13 results on '"Appavoo, Divambal"'

1. Four-Dimensional Printing of Multi-Material Origami and Kirigami-Inspired Hydrogel Self-Folding Structures.

Author

Appavoo, Divambal, Azim, Nilab, Elshatoury, Maged, Antony, Dennis-Xavier, Rajaraman, Swaminathan, and Zhai, Lei

Subjects
*POLY(ISOPROPYLACRYLAMIDE), *THREE-dimensional printing, *STRUCTURAL design, *POLYETHYLENE glycol, *SIMULATION software
Abstract

Four-dimensional printing refers to a process through which a 3D printed object transforms from one structure into another through the influence of an external energy input. Self-folding structures have been extensively studied to advance 3D printing technology into 4D using stimuli-responsive polymers. Designing and applying self-folding structures requires an understanding of the material properties so that the structural designs can be tailored to the targeted applications. Poly(N-iso-propylacrylamide) (PNIPAM) was used as the thermo-responsive material in this study to 3D print hydrogel samples that can bend or fold with temperature changes. A double-layer printed structure, with PNIPAM as the self-folding layer and polyethylene glycol (PEG) as the supporting layer, provided the mechanical robustness and overall flexibility to accommodate geometric changes. The mechanical properties of the multi-material 3D printing were tested to confirm the contribution of the PEG support to the double-layer system. The desired folding of the structures, as a response to temperature changes, was obtained by adding kirigami-inspired cuts to the design. An excellent shape-shifting capability was obtained by tuning the design. The experimental observations were supported by COMSOL Multiphysics® software simulations, predicting the control over the folding of the double-layer systems. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Synthesis and characterization of fullerene-pyridyl arene ruthenium complexes

Author

Appavoo, Divambal, Deschenaux, Robert, and Therrien, Bruno

Abstract

Association of [60]fullerene with arene ruthenium moieties has been achieved for the first time. Two fullerenopyrrolidine derivatives (Npyr-C60) were synthesized via a 1,3-dipolar cycloaddition, and coordinated to arene ruthenium complexes to form two half-sandwich complexes of the general formula (p-cymene)RuCl2(Npyr-C60). The coordination of the fullerenopyrrolidines to the arene ruthenium unit was evidenced by NMR spectroscopy and mass spectrometry, thus confirming the formation of these novel arene ruthenium complexes.

Published
2017

9. NMR spectroscopy and DFT calculations of a self-assembled arene ruthenium rectangle obtained from a combination of coordination and hydrogen bonds

Author

Appavoo, Divambal, Raja, Nandhagopal, Deschenaux, Robert, Therrien, Bruno, Carnevale, Diego, Appavoo, Divambal, Raja, Nandhagopal, Deschenaux, Robert, Therrien, Bruno, and Carnevale, Diego

Abstract

The hydrogen-bonded arene ruthenium metalla-rectangle, [(p-cymene) 2Ru2(OOnOO)(UPy)2]24+ , obtained from 1-(4-oxo-6-undecyl-1,4-dihydropyrimidin-2-yl)-3-(pyridin-4- ylmethyl)urea (UPy) and the dinuclear arene ruthenium clip (p-cymene) 2Ru2(OOnOO)Cl2 (OOnOO = 2,5-dioxido-1,4- benzoquinonato), is investigated by means of solution-phase NMR spectroscopy. Rotating frame nuclear Overhauser effect measurements are used to probe the H- bond network that drives the UPy self-assembly as well as the full rectangular supramolecular system. An effective distance that takes into account both intra-and intermolecular polarization-transfer pathways is utilised for data analysis. The experimental findings are corroborated by DFT calculations of NMR parameters and internuclear distances, thus confirming the formation of a very stable tetranuclear metalla-assembly.

Published
2017

11. SYNTHESIS AND CHARACTERIZATION OF FULLERENEPYRIDYL ARENE RUTHENIUM COMPLEXES.

Author

Appavoo, Divambal, Deschenaux, Robert, and Therrien, Bruno

Subjects
FULLERENES, GRAPHENE synthesis, RUTHENIUM compound synthesis, ARENE epoxides, NUCLEAR magnetic resonance spectroscopy, PYRIDYL compounds
Abstract

The article discusses the synthesis of fullerene and arene ruthenium moieties by focusing on the merger of the carbon molecule and ruthenium complexes tested by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. The article also provides characterization of the carbon molecule and arene ruthenium complexes.

Published
2015

12. Synthesis and characterization of fullerene-pyridyl arene ruthenium complexes

Author

Appavoo, Divambal, Deschenaux, Robert, Therrien, Bruno, Appavoo, Divambal, Deschenaux, Robert, and Therrien, Bruno

Abstract

Association of [60]fullerene with arene ruthenium moieties has been achieved for the first time. Two fullerenopyrrolidine derivatives (Npyr-C60) were synthesized via a 1,3-dipolar cycloaddition, and coordinated to arene ruthenium complexes to form two half-sandwich complexes of the general formula (p-cymene)RuCl2(Npyr-C60). The coordination of the fullerenopyrrolidines to the arene ruthenium unit was evidenced by NMR spectroscopy and mass spectrometry, thus confirming the formation of these novel arene ruthenium complexes.

13. NMR spectroscopy and DFT calculations of a self-assembled arene ruthenium rectangle obtained from a combination of coordination and hydrogen bonds

Author

Appavoo, Divambal, Raja, Nandhagopal, Deschenaux, Robert, Therrien, Bruno, Carnevale, Diego, Appavoo, Divambal, Raja, Nandhagopal, Deschenaux, Robert, Therrien, Bruno, and Carnevale, Diego

Abstract

The hydrogen-bonded arene ruthenium metalla-rectangle, [(p-cymene) 2Ru2(OOnOO)(UPy)2]24+ , obtained from 1-(4-oxo-6-undecyl-1,4-dihydropyrimidin-2-yl)-3-(pyridin-4- ylmethyl)urea (UPy) and the dinuclear arene ruthenium clip (p-cymene) 2Ru2(OOnOO)Cl2 (OOnOO = 2,5-dioxido-1,4- benzoquinonato), is investigated by means of solution-phase NMR spectroscopy. Rotating frame nuclear Overhauser effect measurements are used to probe the H- bond network that drives the UPy self-assembly as well as the full rectangular supramolecular system. An effective distance that takes into account both intra-and intermolecular polarization-transfer pathways is utilised for data analysis. The experimental findings are corroborated by DFT calculations of NMR parameters and internuclear distances, thus confirming the formation of a very stable tetranuclear metalla-assembly.

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