Magnetic Polymers

Metallo-supramolecular modules as a paradigm for materials science

“…Owing to the Cu(II) centers, these polymers are paramagnetic and a weak exchange interaction of antiferromagnetic character between the copper centers was detected. Although many other systems have been reported in the literature [57], strong coupling between the metal centers, and, therefore, cooperative phenomena are generally not observed because the distance between the metal centers is too large [58]. The rich chemistry of terpyridines has afforded a number of other interesting ligands with photoluminescent properties, as reported by Würthner and co-workers [59,60], as well as chiral coordination polymers [61,62].…”

Can DFT calculations help the molecular designer to construct molecule based magnetic materials?

“…However, as the exchange coupling J is proportional to r -n (n ≥ 6 for superexchange pathways) [20] changes in r have dramatic effects on the coupling. Supposing that J is also proportional to the product of the spin densities, a simple calculations with n = 6 tells us that if the shortest distance is 2.45 Å, and the alternative pathway is 2.70 Å (a 10% increase) the atom interacting at the longer distance has to have a 80% higher spin density to reach the same magnitude of interaction.…”

Metallopolymers with Schiff Base Side Chains. Synthesis and Characterization of Some Nickel(II) Containing Polymers with Unexpected Cooperative Magnetic Properties

“…Here C 00 are the spin Hamiltonian parameters which can be easily related to the J ij parameters appearing in (3). For example C 00 (1100...00) = -ffiffi ffi 3 p /2 J 12 , C 00 (01110...00) = -ffiffi ffi 3 p /2 J 23 , etc.…”

“…No systematic investigation has been reported so far for the full clarification of this phenomenon involving the structure of the polymer. A substantial work devoted to this problem was presented by F. Palacio et al [3] The number of reports on crosslinked liquid crystalline polymers with paramagnetic units is still very limited. [4] Hanabusa et al [5] reported on the LC properties of a polyacrylate b-diketonate containing copper as the first example of a metal containing LC side chain polymer.…”