SYNTHESES OF MODEL OLIGOMERS FOR POLYIONIC ORGANIC FERROMAGNETICS ANDTHEIR HIGH-SPIN CHARACTERIZATION BY FT PULSED ESR ELECTRON-SPIN TRANSIENT NUTATION (ESTN) SPECTROSCOPY AS A NOVEL EXPERIMENTAL-TECHNIQUE

This paper deals with syntheses and unequivocal spin identification of prototypical model oligomers for the pi-topological version of an app roach to purely organic polyionic polymer ferromagnets, emphasizing th at molecular design exploits the topological super pseudo-degeneracy o f pi-bonding and pi-antibonding molecular orbitals (pi-HOMOs and pi-LU MOs) appearing close to zero energy in heteroatomic pi-conjugated orga nic systems, for polycationic and polyanionic organic polymeric high s pins, respectively. The oxidation and reduction states of the oligomer s designed according to the topological approach are expected to under go dynamic spin polarization, leading to high-spin ground states for b oth polycationic and polyanionic model oligomers. One-dimensional and two-dimensional star-burst polycationic model oligomers with heteroato ms participating in pi-conjugation were designed and synthesized Their electronic high-spin ground states have been identified by means of T wo-Dimensional Electron Spin Transient Nutation (2D-ESTN) spectroscopy based on an FT pulsed ESR technique to which recently we have exerted ourselves in order to obtain technical advances in molecular spin sci ence underlying the research field of molecule-based magnetics. In thi s study, the polyketone-based polyanionic high-spin species have been generated also by a dry process, i.e., electron doping by gamma-irradi ation in organic glasses.