Abstract

Two pairs of nitronyl nitroxide radicals with specific molecular structures in which the imidazole radical moiety was directly bound to their chiral center have been prepared in their enantiopure forms. In these specific molecular structures, chirality may directly affect the unpaired spin electronic cloud. The X-ray crystal structures of them have been solved, which reveal that supermolecule helical chains are formed by intermolecular hydrogen bond interactions in the l-NNP crystal and the l-NNNBP is a 3D supermolecule structure shaped by means of intermolecular hydrogen bond interactions to link homochiral chains. Circular dichroism spectroscopy of the two pairs of chiral α-nitronyl nitroxides shows significant Cotton effects between 200 and 400 nm. The magnetic properties of the two pairs of nitronyl nitroxide radicals in the solid state were characterized by EPR spectroscopy and magnetic susceptibility measurements, respectively. Magnetic susceptibility measurements of the solids reveal antiferromagnetic interactions in all cases. However, in the l-NNNBP, the exchange interaction abruptly changes from untiferromagnetic to a ferromagnetic interaction at 40.0 k.

Full Text
Paper version not known

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 call

Disclaimer: 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.