Unusually Large Coupling Constants in Diradicals Obtained from Excitation of Mixed Radical Centers: A Theoretical Study on Potential Photomagnets
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Title |
Unusually Large Coupling Constants in Diradicals Obtained from Excitation of Mixed Radical Centers: A Theoretical Study on Potential Photomagnets
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Creator |
BHATTACHARJEE, U
PANDA, A LATIF, IA DATTA, SN |
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Subject |
intramolecular magnetic interaction
nitronyl nitroxide hartree-fock spin states diarylethene wavefunctions abinitio couplers bonds |
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Description |
Three sets of heterosubstituted, interconvertible, cyclophanediene (CPD), and dihydropyrenes (DDPs) and one such set involving dinitrilepyrenes were examined by UB3LYP broken-symmetry methodology with 6-311++g(d,p) bases. Nitronyl nitroxide and oxoverdazyl (with both N and C terminals) are monoradical centers, whereas CPD and DDP moieties serve as couplers. The photoexcited CPD converts to DDP. The calculated exchange coupling, constant (J) for o-VER(N)-DDP-NN is surprisingly high, 6412 cm(-1), and much larger than 28.9 cm(-1) for the CPD species, but the unsubstituted DDP is known to transform readily into pyrene, with the loss of reversibility. Nevertheless, o-VER(N)-(15,16-dinitrile)DDP-NN also has a large J value, 589.4 cm(-1). The corresponding CPD species has J = 53.3 cm(-1). We predict that the latter CPD and DDP diradicals are potential molecules to synthesize photomagnetic materials. The o-VER(N)-DDP-NN can also be an excellent photomagnetic switch at a considerably low temperature.
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Publisher |
AMER CHEMICAL SOC
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Date |
2011-07-15T04:01:10Z
2011-12-26T12:49:14Z 2011-12-27T05:35:02Z 2011-07-15T04:01:10Z 2011-12-26T12:49:14Z 2011-12-27T05:35:02Z 2010 |
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Type |
Article
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Identifier |
JOURNAL OF PHYSICAL CHEMISTRY A, 114(24), 6701-6704
1089-5639 http://dx.doi.org/10.1021/jp102939m http://dspace.library.iitb.ac.in/xmlui/handle/10054/4148 http://hdl.handle.net/10054/4148 |
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Language |
en
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