Göbel Christoph, Palamarciuc Tatiana, Lochenie Charles, Weber Birgit
Inorganic Chemistry II, Universität Bayreuth, Universitätsstraße 30, NW 1, 95440 Bayreuth (Germany), Fax: (+49) 92155-2157.
Chem Asian J. 2014 Aug;9(8):2232-8. doi: 10.1002/asia.201402144. Epub 2014 Jun 17.
Microcrystals of the spin-crossover coordination polymer [FeL(bipy)] (L=[3,3']-[1,2-phenylenebis(iminoethylidyne)]bis-(2,4-pentanedionato)(2-), bipy=4,4'-bipyridine) have been prepared in a poly(4-vinylpyridine) (P4VP) matrix. This was done by sequential addition of the iron(II) precursor complex and the bridging ligand bipy to a P4VP matrix, and by repetition of this cycle. The obtained composite material was characterized using TEM, SEM, XRPD, and SQUID measurements, and Mössbauer spectroscopy. With repeating cycles, the size of the [FeL(bipy)] crystals in the P4VP matrix increases from submicrometer to micrometer dimensions. A strong dependence on the number of cycles is observed. Above a critical size and concentration, the microcrystals show the same cooperative spin transition as the bulk material. No indication for a gradual spin transition is observed, but the remaining iron centers are either high-spin or low-spin depending on the coordination environment.
自旋交叉配位聚合物[FeL(bipy)]（L = [3,3']-[1,2-亚苯基双(亚氨基次乙基)]双-(2,4-戊二酮酸根)(2-)，bipy = 4,4'-联吡啶）的微晶已在聚(4-乙烯基吡啶)(P4VP)基质中制备出来。这是通过将铁(II)前体配合物和桥联配体bipy依次加入到P4VP基质中，并重复此循环来实现的。使用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线粉末衍射(XRPD)、超导量子干涉仪(SQUID)测量以及穆斯堡尔光谱对所得复合材料进行了表征。随着循环次数的增加，P4VP基质中[FeL(bipy)]晶体的尺寸从亚微米级增大到微米级。观察到对循环次数有强烈依赖性。在超过临界尺寸和浓度时，微晶显示出与块状材料相同的协同自旋转变。未观察到逐渐自旋转变的迹象，但是剩余的铁中心根据配位环境要么是高自旋要么是低自旋。
