Effect of pressure and light on spin crossover and molecular magnetic interactions

该提案的主要目标之一是研究新合成的铁（II）自旋交叉配合物与三唑和四唑配体和1-D，2-D和3-D晶格结构所带来的氢键和/或p-p-堆叠的合作相互作用。对于定量解释，所谓的“美因茨模型”的弹性相互作用将在金属稀释的混合晶体系列和压力的影响下进行测试。该模型已被开发和成功测试单核（即零维）铁（II）自旋交叉化合物。将进行LIEST效应研究，以了解弛豫动力学是否与晶格维度相关。- 另一个目标是研究压力对具有磁交换相互作用的选定分子系统的影响。待研究的一类是普鲁士蓝型化合物。初步的实验表明，施加压力诱导电子转移之前的自旋状态切换发生。另一类系统的压力下进行研究的二，三和寡铁（II）化合物关于反铁磁耦合和热和压力引起的自旋交叉的相互作用。我们将采用一种直接监测金属对形成过程中自旋态的方法，预期结果将支持关联和短程相互作用的存在。

One the main goals of this proposal is the study of the cooperative interactions in newly synthesized iron(II) spin crossover complexes with triazole and tetrazole ligands and 1-D, 2-D, and 3-D lattice structures brought about by hydrogen bonding and/or p-p-stacking. For a quantitative interpretation, the so-called "Mainz model" of elastic interactions will be tested on metal-diluted mixed crystal series and under the influence of pressure. This model has been developed and successfully tested for mononuclear (i.e. zero-dimensional) iron(II) spin crossover compounds. LIESST effect studies will be performed in order to learn whether the relaxation kinetics correlates with the lattice dimensionality. - Another goal is the investigation of the effect of pressure on selected molecular systems with magnetic exchange interactions. One class to be studied are the Prussian Blue type compounds. Preliminary experiments show that applying pressure induces electron transfer before the spin state switching occurs. Another class of systems to be studied under pressure are di-, tri- and oligonuclear iron(II) compounds regarding the interplay of antiferromagnetic coupling and thermal and pressure-induced spin crossover. A method for direct monitoring the spin state in metal-pair formations will be employed.The results are expected to lend support for the existence of correlations and short range interactions.