SYNTHESIS AND PROPERTIES OF IRON(III) PORPHYRIN COMPLEXES WITH NOVEL SPIN STATE

i)通过弱THF配体配位到具有高度卷曲的卟啉环的铁（III）配合物上，我们能够制备本质上纯的中间自旋配合物。^<13>C核磁共振测量表明，这些配合物采用新的（d_<xz>, d_<yz>）^3(d_<xy>)^1(d_z^2)^1电子构型；先前报道的中间自旋铁（III）配合物被认为具有（d_<xy>）^2(d_<xz>, d_<yz>)^2(d_z^2)^1电子构型。ii)研究了低自旋（S = 1）高皱褶卟啉环锰（III）配合物的电子构型。与相应的铁（III）配合物的情况相反，它们显示出共同的（d_<xy>）^2(d_<xz>, d_<yz>)^2电子构型。结果表明，在锰配合物中，即使卟啉环高度皱褶，d_π轨道的能量也高于d_<xy>轨道。iii)用吡啶和取代吡啶处理高鞍卟啉环铁（iii）配合物。用^1H NMR、^<13>C NMR、EPR、穆斯堡尔谱、x射线晶体学和SQUID磁强计等方法研究了所形成的bis（吡啶）配合物的磁性能。该配合物在溶液中表现出S = 1/2和S = 3/2的自旋交叉，而在固体中则保持S = 1/2。在不同温度下的x射线晶体学测量表明，该配合物在晶格中紧密堆积。因此，轴向配体改变fe -配体键长的空间很小。在这些结果的基础上，我们得出结论，络合物需要在轴向配体周围有足够的空腔来显示自旋交叉过程。

i)By the coordination of weak THF ligand to the iron(III) complexes with highly ruffled porphyrin ring, we were able to prepare essentially pure intermediate spin complexes. The ^<13>C NMR measurements have revealed that these complexes adopt a novel (d_<xz>, d_<yz>)^3(d_<xy>)^1(d_z^2)^1 electron configuration; the intermediate spin iron(III) complexes reported previously are believed to have (d_<xy>)^2(d_<xz>, d_<yz>)^2(d_z^2)^1 electron configuration.ii)The electron configuration of the low spin (S = 1) manganese(III) complexes with highly ruffled porphyrin ring has also been examined. In contrast to the case of the corresponding iron(III) complexes, they have shown a common (d_<xy>)^2(d_<xz>, d_<yz>)^2 electron configuration. The result suggests, that the d_π orbitals are located higher in energy than the d_<xy> orbital in the case of manganese complexes even if the porphyrin ring is highly ruffled.iii)The iron(III) complex with highly saddled porphyrin ring was treated with pyridine and substituted pyridine. The magnetic properties of the bis(pyridine) complex thus formed were examined by ^1H NMR, ^<13>C NMR, EPR, and Mossbauer spectroscopy as well as X-ray crystallography and SQUID magnetometry. While the complex showed a spin crossover between the S = 1/2 and S = 3/2 spin states in solution, the same complex maintained the S = 1/2 in the solid. The X-ray crystallographic measurements at different temperatures have revealed that the complex is tightly packed in the crystal lattice. Consequently, there is little space for the axial ligand to change the Fe-Ligand bond length. On the basis of these results, we have concluded that the enough cavity is necessary around the axial ligand for the complex to show the spin crossover process.