Dipartimento di Chimica Ugo Schiff and INSTM RU, Università degli Studi di Firenze, Via della Lastruccia 3-13, 50019 Sesto Fiorentino-FI, Italy.
Dalton Trans. 2013 Apr 7;42(13):4416-26. doi: 10.1039/c2dt32618c.
Propeller-like [Fe(4)(L)(2)(dk)(6)] complexes, in which Hdk is a β-diketone and H(3)L is a tripodal alcohol, R-C(CH(2)OH)(3), exhibit tunable magnetic anisotropy barriers and retain their magnetic memory effect when chemically anchored on metal surfaces. Heteronuclear analogues of these M(4) complexes have been sought to afford a library of compounds with different total spin (S) values, but synthetic efforts described so far gave solid solutions containing M(4) in addition to the desired M(3)M' species. We now present a novel synthetic route to M(3)M' complexes featuring a central chromium(III) ion. The three-step preparation goes through coordination of Cr(III) by two equivalents of tripodal alkoxide (R = Et and Ph), followed by reaction of this complex "core" with the peripheral +III metal ions. Products have been characterised by chemical analyses together with (1)H-NMR, FTIR, W-band EPR, DC/AC magnetic susceptibility measurements and single crystal X-ray diffractometry. Due to the chemical inertness of Cr(III), this route yields 100% pure Fe(3)Cr complexes without metal scrambling; what is more, it is suitable for designing novel heteronuclear single molecule magnets (SMMs) with a variety of d- and f-metals and R groups.
具有螺旋桨状结构的[Fe(4)(L)(2)(dk)(6)]配合物，其中 Hdk 是一种β-二酮，H(3)L 是三齿醇 R-C(CH(2)OH)(3)，表现出可调的各向异性磁阻垒，并且在化学固定在金属表面时保留其磁记忆效应。这些 M(4)配合物的杂核类似物已经被寻求提供具有不同总自旋（S）值的化合物库，但迄今为止描述的合成努力给出了除所需的 M(3)M'物种之外还含有 M(4)的固溶体。我们现在提出了一种制备具有中心铬(III)离子的 M(3)M'配合物的新合成途径。该三步制备过程通过三齿烷氧基（R = Et 和 Ph）与 Cr(III)配位，然后使该“核心”配合物与外围+III 金属离子反应。通过化学分析以及（1）H-NMR、FTIR、W 波段 EPR、直流/交流磁化率测量和单晶 X 射线衍射法对产物进行了表征。由于 Cr(III)的化学惰性，该路线可获得 100%纯 Fe(3)Cr 配合物，没有金属混排；更重要的是，它适合设计具有各种 d 和 f 金属和 R 基团的新型异核单分子磁体（SMM）。
