Abstract
A series of liquid-crystalline materials based on 4-substituted cyanobiphenyls, RC(6)H(4)C(6)H(4)CN (R = C(5)H(11), C(6)H(13), C(7)H(15), C(8)H(17) and C(12)H(25), commonly referred to as 5CB, 6CB, 7CB, 8CB and 12CB, respectively) were functionalised to give the corresponding dithiadiazolyl organic radicals RC(6)H(4)C(6)H(4)CNSSN(*) (compounds 1(*), 2(*), 3(*), 4(*) and 5(*), respectively). EPR spectra of n-C(12)H(25)C(6)H(4)C(6)H(4)CNSSN(*) (5(*)) reveal that it adopts a dimeric diamagnetic structure in the solid state with a small number of paramagnetic defect sites. Variable temperature electron paramagnetic resonance (EPR) studies reveal a thermally activated rotation about the molecular long axis at temperatures above 314 K. The energy barrier to rotation about the phenylene-dithiadiazolyl bond was estimated as 25 kJ mol(-1) using density functional theory (DFT). At elevated temperatures thermal annealing was also observed, quenching the sample's paramagnetism.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
