Propeller-like [Fe4(L)2(dk)6] complexes, in which Hdk is a β-diketone and H3L is a tripodal alcohol, R–C(CH2OH)3, exhibit tunable magnetic anisotropy barriers and retain their magnetic memory effect when chemically anchored on metal surfaces. Heteronuclear analogues of these M4 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 M4 in addition to the desired M3M′ species. We now present a novel synthetic route to M3M′ complexes featuring a central chromium(III) ion. The three-step preparation goes through coordination of CrIII 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 1H-NMR, FTIR, W-band EPR, DC/AC magnetic susceptibility measurements and single crystal X-ray diffractometry. Due to the chemical inertness of CrIII, this route yields 100% pure Fe3Cr 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.
螺旋桨状[Fe4(L)2(dk)6]复合物中,Hdk为
β-二酮,H3L为三足醇R-C(CH2OH)3,该复合物具有可调的磁性各向异性屏障,在
化学锚定在
金属表面时仍能保持其磁性记忆效应。人们一直在寻找这些
M4复合物的异核类似物,以获得具有不同总自旋(S)值的化合物库,但迄今为止的合成工作只得到了含有
M4和所需M3M′物质的固体溶液。我们现在提出了一种以中心
铬(III)离子为特征的M3M′复合物的新合成路线。该三步制备过程包括用两当量的三足烷氧基(R = Et和Ph)配位
铬(III),然后让这个复合物“核心”与外围+III
金属离子反应。通过
化学分析以及1H-NMR、FTIR、W波段EPR、DC/AC磁化率测量和单晶X射线衍射法对产物进行了表征。由于CrIII的
化学惰性,该路线可产生100%纯的
铁铬复合物,且不会发生
金属混乱;更重要的是,它适用于设计具有各种d-和f-
金属和R基团的新型异核单分子磁
铁(
SMM)。