Organic Magnetic Polymers

Redox Modulation of para-Phenylenediamine by Substituted Nitronyl Nitroxide Groups and Their Spin States

“…The quartet state of 2 ′ + has three singly occupied molecular orbitals (SOMOs), depicted in Figure , where the almost degenerate two SOMOs (65a g and 64a u ) composed of the π-orbitals on the substituted NN groups are nearly degenerate with the SOMO (64a g ) composed of the π-orbital on the central PDA unit. Apparently, 2 ′ + is regarded as a non-disjoint (or coextensive ) system, − where the same atomic orbitals are shared among the SOMOs. Since the high–spin state is relatively stabilized owing to exchange interaction in the non-disjoint system, the quartet state is expected to be lower in energy than the competing doublet state in 2 ′ + .…”

High-spin polymeric arylamines

“…However, unlike molecular magnets, polymer magnets should make it possible to exploit strong through-bond exchange interactions, and higher Curie temperatures should result. Whether we are dealing with atomic, molecular or macromolecular systems, the conditions for Hund's Rule to apply are the same (Bushby et al . 1996).…”

“…This is significant since ferromagnetic coupling always breaks down in one-dimensional systems if the chains are sufficiently long. If the ultimate aim is to make a bulk ferromagnet, the incorporation of these branched 'building blocks' is crucial since it allows the creation of two-and threedimensional networked macromolecular structures which solve the 'dimensionality problem' (Bushby et al . 1996).…”

“…Initially we experienced difficulty in obtaining quantitative or even nearly quantitative doping of these arylamine polymers (Bushby et al . 1996(Bushby et al .…”

“…We have previously shown that when 15% of the available sites in the hexyloxy 'homologue' of polymer 15 were oxidized to the N •+ level, the field dependence of the bulk magnetization at 2 K fitted a Brillouin function, S = 5 2 (Bushby et al . 1996(Bushby et al .…”