Axially Ligated Phthalocyanine Conductors with Magnetic Moments
AbstractThis mini-review describes electrical conductivity, magnetic properties, and magnetotransport properties of one-dimensional partially oxidized salts composed of axially ligated phthalocyanines, TPP[M(Pc)(CN)2]2 (TPP = tetraphenylphosphonium, Pc = phthalocyaninato), with M of Fe (d5, S = 1/2) and Cr (d3, S = 3/2). These salts are isomorphous, and π–π interactions in the crystal, that becomes the origin of the charge carriers, are nearly the same. Both the Fe and Cr salts show carrier localization and charge disproportionation which is enhanced by the interaction between local magnetic moments and conduction π-electrons (π–d interaction). However, the magnetic properties are slightly different between them. M = Fe has been found to show unique anisotropic magnetic properties and antiferromagnetic short-range magnetic order between the d-spins. On the other hand, for M = Cr, its magnetic moment is isotropic. Temperature dependence of the magnetic susceptibility shows typical Curie–Weiss behavior with negative Weiss temperature, but the exchange interaction is complicated. Both M = Fe and M = Cr show large negative magnetoresistance, reflecting the difference in the anisotropy. The magnetoresistance ratio (MR) is larger in the Fe system than in the Cr system in the low magnetic field range, but MR in the Cr system exceeds that in the Fe system when the magnetic field becomes higher than 15 T. We discuss the mechanism of the giant negative magnetoresistance with reference to the d–d, π–d, and π–π interactions. View Full-Text
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Inabe, T.; Hanasaki, N. Axially Ligated Phthalocyanine Conductors with Magnetic Moments. Magnetochemistry 2017, 3, 18.
Inabe T, Hanasaki N. Axially Ligated Phthalocyanine Conductors with Magnetic Moments. Magnetochemistry. 2017; 3(2):18.Chicago/Turabian Style
Inabe, Tamotsu; Hanasaki, Noriaki. 2017. "Axially Ligated Phthalocyanine Conductors with Magnetic Moments." Magnetochemistry 3, no. 2: 18.
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