DSpace
 

DSpace at IIT Bombay >
IITB Publications >
Article >

Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/100/14248

Title: Photoswitching Magnetic Crossover in Organic Molecular Systems
Authors: SAHA, A
LATIF, IA
DATTA, SN
Keywords: DENSITY-FUNCTIONAL THEORY
FERROMAGNETICALLY COUPLED DIRADICALS
TRANSITION-METAL DIMERS
MIXED RADICAL CENTERS
NITRONYL NITROXIDE
CORRESPONDING ORBITALS
HARTREE-FOCK
SPIN STATES
DIARYLETHENE
BOND
Issue Date: 2011
Publisher: AMER CHEMICAL SOC
Citation: JOURNAL OF PHYSICAL CHEMISTRY A,115(8)1371-1379
Abstract: We have theoretically designed efficient photomagnetic diradicals using both substituted and unsubstituted cyclophanediene (CPD) and dihydro-pyrenes (DHP) as spacers. Nitronyl nitroxide (NN), oxoverdazyl (o-VER), and tetrathiafulvalene (TTF) are chosen as monoradical centers. Molecular geometries have been optimized by the density functional method UB3LYP using the 6-311G (d,p) basis set. Final single point calculations have been done with the 6-311++G(d,p) basis. Absorption wavelengths have been estimated from time-dependent density functional treatment using restricted spin-polarized density functionals (RB3LYP) and 6-31G basis. Both the substituted and unsubstituted CPD species with mixed monoradical centers are found to be antiferromagnetically coupled. Diradicals with the same centers but with DHP coupler exhibit strong ferromagnetic coupling. Also, photoexcitations of the diradicals are generally red-shifted by only a few nanometers from those of the 15,16-dimethyl pyrenes. This indicates that on photoexcitation a consistent magnetic crossover from an antiferromagnetic to a ferromagnetic regime is possible. The accompanying change in magnetic exchange coupling constant Delta J is very large, varying from 445 to 1003 cm(-1). As far as organic molecular magnetism is concerned, this observation is entirely new and likely to be of technological significance.
URI: http://dx.doi.org/10.1021/jp107049u
http://dspace.library.iitb.ac.in/jspui/handle/100/14248
ISSN: 1089-5639
Appears in Collections:Article

Files in This Item:

There are no files associated with this item.

View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback