自旋转换/自旋双稳性化合物是新型机敏材料，在未来分子热开关、光开关和信息存储等高技术领域具有重要应用前景。本项目拟开展'同位素取代调控一维spin-Peierls-type分子磁体磁相变性质'方面研究工作。通过对我们前期发现的一系列一维过渡金属二硫烯spin-Peierls-type自旋转换/自旋双稳性化合物中各组分逐步同位素取代，比较研究其单晶结构、磁、相变热力学、晶格振动等性质。用第一性原理计算一维晶体能带结构、分析Fermi能级附近态密度，揭示spin-Peierls-type磁相变同位素效应内在机制、协同spin-Peierls-type磁相变的关键晶格振动模、以及影响spin-Peierls-type磁相变性质关键因素。在实验和理论基础上，建立同位素取代-磁相变性质之间相关性，发展同位素取代调控磁相变性质的方法。为设计、定向合成关键技术参数满足实用要求的磁相变化合物提供理论依据。

Spin transition/spin bistability compounds are the new type of technically-important functional material, which possess the potential applications in the technical areas, such as, thermal switch, optical switch and information storage. In this project, we will develop a strategy for tuning the magnetic and phase transition features of the one-dimensional spin-Peierls-type compounds, which are based on metal-bis-dithiolene building blocks, via isotope substitution. In our previous studies, a series of organic cations with flexible molecular conformation were designed and combined with the magnetic metal-bis-dithiolene anions to give one-dimensional molecule-based magnets, and those molecule magnets showed one or two steps of spin-Peierls-type transition at a certain temperature, which are promoted by the strong spin-lattice coupling interactions. Theoretically, the spin-Peierls-type transition and magnetic feature of one-dimensional metal-bis-dithiolene compounds are probably varied with the isotope substitutions for the components of the compound since the lattice vibration feature and the zero-point energy are related to the molecule mass. The components of spin-Peierls-type compounds, based on metal-bis-dithiolene building blocks, will sequentially be isotopely substituted and the corresponding substitued compounds are comparelly investigated in the aspects of vibration spectroscopies, crystal structures, magnetic, phase transition and thermodynamic properties. Based on the calculation using the First-principles electronic band structure theory for the one-dimensional spin-Peierls-type molecule magnets, the density of states near the Fermi level will be further analyzed, which be expected to reveal the issues, for instance, the intrinsic mechanism of the isotope effect on the spin-Peierls-type transition,the crucial lattice vibration models as well as other factors that affect strongly on the spin-Peierls-type transition feature. The correlation of isotope substitution and spin-Peierls-type transtion feature will be built and the approach for tuning the spin transition property via isotope substitution will be developed as well. This study will be aim to provide the useful information for the desination and contrallable preparation of new spin transition functional compounds whose properties, such as the critical temperature and the hysteretic loop width, are hoped to meet the technical requirements.