473249-39-7Relevant academic research and scientific papers
Magnetic semiconductor: Structural, magnetic, and conducting properties of the salts of the 6-oxoverdazyl radical cation with M(dmit)2 anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate)
Mukai,Hatanaka,Senba,Nakayashiki,Misaki,Tanaka,Ueda,Sugimoto,Azuma
, p. 5066 - 5074 (2002)
Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation [V]+ with M(dmit)2 anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([V]+[Ni(dmit)2]- (1), [V]+[Ni(dmit)2]3- (2), [V]+2[Zn(dmit)2]2- (3), [V]+2[Pd(dmit)2]2- (4), and [V]+2[Pt(dmit)2]2- (5)) and an iodide salt of [V]+ ([V]+[I]- (6)) have been prepared, and the magnetic susceptibilities (χM values) have been measured between 1.8 and 300 K. The χM of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (θ) of -1.5 K and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2JA-B/kB = -274 K (alternation parameter α = JA-C/JA-B = 0.2). The χM of the (1:3) Ni salt (2) can be well explained by the two-term contributions from (i) the Curie-Weiss system with C = 0.376 K emu/mol and θ = -5.0 K and (ii) the dimer system with 2J/kB = -258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure analysis and ESR measurements of 1 and 2. The χM values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V]+[I]- salt 6 follow the Curie-Weiss law with C = 0.723, 0.713, 0.712, and 0.342 K emu/mol and θ = -2.8, -3.1, -2.6, and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (σ) of the Ni salt 2 and Pd salt 4 at 20 °C was σ = 8.9 × 10-2 and 1.3 × 10-4 S cm-1 with an activation energy EA = 0.11 and 0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.
