Haraguchi Makoto, Tretyakov Evgeny, Gritsan Nina, Romanenko Galina, Gorbunov Dmitry, Bogomyakov Artem, Maryunina Kseniya, Suzuki Shuichi, Kozaki Masatoshi, Shiomi Daisuke, Sato Kazunobu, Takui Takeji, Nishihara Sadafumi, Inoue Katsuya, Okada Keiji
Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan.
Vorozhtsov Institute of Organic Chemistry, Russian Academy of Sciences, Ak. Lavrentiev Avenue 9, 630090, Novosibirsk, Russian Federation.
Chem Asian J. 2017 Nov 16;12(22):2929-2941. doi: 10.1002/asia.201701085. Epub 2017 Oct 31.
In contrast to diradicals connected by alternant hydrocarbons, only a few studies on those connected by nonalternant hydrocarbons have been reported. The syntheses, structures, and magnetic properties of azulene-1,3-diyl linked bis(nitronyl nitroxide) (NN Az) and bis(iminonitroxide) (IN Az) diradicals and their Cu(hfac) (hfac=hexafluoroacetylacetonate) complexes were investigated. NN Az was shown to have an intramolecular ferromagnetic interaction with J /k =+10.0 K (H=-2JS ⋅S ) between (nitronyl nitroxide) spins, whereas IN Az was estimated to have a much weaker intramolecular magnetic interaction. The reactions of NN Az and IN Az with Cu(hfac) gave a 1:2 [{Cu(hfac) } (NN Az)] complex and a 1:1 [Cu(hfac) (IN Az)]⋅C H complex, respectively. [{Cu(hfac) } (NN Az)] showed strong intramolecular antiferromagnetic interactions (J /k ≈-800 K, J /k ≈-500 K) between the Cu spins and the coordinating NN spins, whereas [Cu(hfac) (IN Az)] exhibited a ferromagnetic exchange interaction (J /k =+114 K) between the Cu spin and the imino-coordinated iminonitroxide spin.
与由交替烃连接的双自由基相比，关于由非交替烃连接的双自由基的研究报道较少。研究了薁-1,3-二基连接的双（硝酰基氮氧化物）（NN Az）和双（亚氨基氮氧化物）（IN Az）双自由基及其Cu（hfac）（hfac = 六氟乙酰丙酮）配合物的合成、结构和磁性。结果表明，NN Az在（硝酰基氮氧化物）自旋之间具有分子内铁磁相互作用，J /k = +10.0 K（H = -2JS ⋅S），而IN Az的分子内磁相互作用估计要弱得多。NN Az和IN Az与Cu（hfac）的反应分别得到1:2的[{Cu（hfac）}₂（NN Az）]配合物和1:1的[Cu（hfac）（IN Az）]⋅C₆H₆配合物。[{Cu（hfac）}₂（NN Az）]在Cu自旋和配位的NN自旋之间表现出强烈的分子内反铁磁相互作用（J /k ≈ -800 K，J /k ≈ -500 K），而[Cu（hfac）（IN Az）]在Cu自旋和亚氨基配位的亚氨基氮氧化物自旋之间表现出铁磁交换相互作用（J /k = +114 K）。
