Solution-grown single crystals of furan/phenylene co-oligomer combine efficient charge transport properties and high fluorescence efficiency.

In the present study we report the synthesis of some novel nitronyl nitroxide biradical systems 1-4c with various p-bridges between the radical centres. UV-Vis, IR, EPR and X-ray diffraction studies, along with MS and NMR data where appropriate, are described. Magnetic measurements revealed that the biradicals 1c, 3c and 4c exhibit a moderately strong antiferromagnetic intra-molecular exchange, whereas nitroxide 2c shows a significantly higher exchange coupling, which can only be explained by the presence of strong inter-molecular interactions. From DFT calculations performed on the basis of the Xray crystal structure of compound 4c, a theoretical value of the intra-dimer coupling constant J intra ¼ À8.6 K is obtained. Direct proof also for inter-molecular arrangement with J inter $ À2 K was provided by the low temperature AC studies of biradical 4c. According to the magnetic characterization, the nitronyl biradical 4c is a promising candidate for a purely organic-based low-dimensional quantum magnet. † Electronic supplementary information (ESI) available: Fig. S1-12 UV-Vis spectra of the nitronyl nitroxides 1-4c, IR spectra of dialdehyde 4a, imidazolidine 4b, biradicals 2c, 3c and 4c, EPR spectra of the biradical 3c, magnetic susceptibility data of compounds 1-3c, TOC graphic of 4c, respectively. CCDC 822066, 816633, 816635. For ESI and crystallographic data in CIF or other electronic format see Scheme 3 Synthetic route towards dialdehydes 3a and 4a. Scheme 4 Synthesis of the imidazolidine 4b and biradical 4c. Scheme 2 Synthetic route towards dialdehyde 2a. 6620 | J. Mater. Chem. C, 2014, 2, 6618-6629 This journal is

Magneto-structural correlations in stable organic biradicals have been studied on example of weakly exchange coupled models with nitronyl nitroxide and imino nitroxide spin-carrying entities.