POLYCATIONIC HIGH-SPIN STATES OF ONE-DIMENSIONAL AND 2-DIMENSIONAL (DIARYLAMINO)BENZENES, PROTOTYPICAL MODEL UNITS FOR PURELY ORGANIC FERROMAGNETIC METALS AS STUDIED BY PULSED ESR ELECTRON SPIN TRANSIENT NUTATION SPECTROSCOPY/

Polycationic high-spin states of 1,3-bis(diarylamino)benzene and 1,3,5 -tris(diarylamino)benzene as prototypical model units for organic ferr omagnetic metals have been studied by cw and pulsed ESR spectroscopy. An electron spin transient nutation (ESTN) method as a novel technique based on pulsed ESR spectroscopy has been applied to the dicationic a nd tricationic high-spin states of them in glasses, unequivocally iden tifying the spin multiplicities of those molecules in the ground state to be triplet with the fine-structure parameters of \D\ = 0.007 cm(-1 ) and quartet with \D\ = 0.004 cm(-1), \E\ = 0.0002 cm(-1), and g = 2. 0023, respectively, and concluding that the high-spin ground states or iginate from the topological pseudodegeneracy of the pi-HOMOs which go verns spin alignment in polycationic heteroatomic systems. It has been illustrated by the resolution enhancement inherent in the dimensional decomposition of 2D spectroscopy that magnetic-field-swept 2D ESTN sp ectroscopy is a powerful and facile method for spin identification and discrimination between different spin multiplicities in nonoriented s ystems. Also, ESTN phenomena have been treated in terms of both numeri cal calculation and perturbation theory. An analytical expression for the nutational motion has been derived.