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• 作者：Nikolay A. Semenov ; Nikolay A. Pushkarevsky ; Elizaveta A. Suturina ; Elena A. Chulanova ; Natalia V. Kuratieva ; Artem S. Bogomyakov ; Irina G. Irtegova ; Nadezhda V. Vasilieva ; Lidia S. Konstantinova ; Nina P. Gritsan ; Oleg A. Rakitin ; Victor I. Ovcharenko ; Sergey N. Konchenko ; Andrey V. Zibarev
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：June 3, 2013
• 年：2013
• 卷：52
• 期：11
• 页码：6654-6663
• 全文大小：548K
• 年卷期：v.52,no.11(June 3, 2013)
• ISSN：1520-510X

文摘

Bis(toluene)chromium(0), Cr⁰(畏⁶-C₇H₈)₂ (3), readily reduced [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (1) and [1,2,5]thiadiazolo[3,4-b]pyrazine (2) in a tetrahydrofuran solvent with the formation of heterospin, S₁ = S₂ = ¹/₂, radical-ion salts [3]⁺[1]^{鈭?/sup> (4) and [3]+[2]鈭?/sup> (5) isolated in high yields. The salts 4 and 5 were characterized by single-crystal X-ray diffraction (XRD), solution and solid-state electron paramagnetic resonance, and magnetic susceptibility measurements in the temperature range 2鈥?00 K. Despite the formal similarity of the salts, their crystal structures were very different and, in contrast to 4, in 5 anions were disordered. For the XRD structures of the salts, parameters of the Heisenberg spin Hamiltonian were calculated using the CASSCF/NEVPT2 and broken-symmetry density functional theory approaches, and the complex magnetic motifs featuring the dominance of antiferromagnetic (AF) interactions were revealed. The experimental 蠂T temperature dependences of the salts were simulated using the Van Vleck formula and a diagonalization of the matrix of the Heisenberg spin Hamiltonian for the clusters of 12 paramagnetic species with periodic boundary conditions. According to the calculations and 蠂T temperature dependence simulation, a simplified magnetic model can be suggested for the salt 4 with AF interactions between the anions ([1]鈭?/sup>路路路[1]鈭?/sup>, J₁ = 鈭?.77 cm鈥?) and anions and cations ([1]鈭?/sup>路路路[3]+, J₂ = 鈭?.84 cm鈥?). The magnetic structure of the salt 5 is much more complex and can be characterized by AF interactions between the anions, [2]鈭?/sup>路路路[2]鈭?/sup>, and by both AF and ferromagnetic (FM) interactions between the anions and cations, [2]鈭?/sup>路路路[3]+. The contribution from FM interactions to the magnetic properties of the salt 5 is in qualitative agreement with the positive value of the Weiss constant 螛 (0.4 K), whereas for salt 4, the constant is negative (鈭?.1 K).}