对于FeIII旋转交叉的对称和不对称体 - - C2轴的影响
Conor T Kelly1, Emmelyne Cuza1, Eoin Pasquetti1
1School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland. conor.kelly3@ucd.ie.
Dalton transactions (Cambridge, England : 2003)
|September 15, 2025
概括
分子对称性影响铁中的自旋状态(III) 希夫基复合体. 有C2轴的对称复合体稳定了低旋转状态,使旋转交叉在室温附近成为可能.
科学领域:
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
- 磁电化学 磁电化学 磁电化学
背景情况:
- 铁(III) 希夫基复合体表现出旋转交叉 (SCO) 行为,在高旋转 (HS) 和低旋转 (LS) 状态之间切换.
- 连接体修饰,特别是胺脊柱长度在六连接体中,影响了这些自旋状态的稳定性.
- 了解控制自旋状态转换的因素对于设计具有可调节磁性质的材料至关重要.
研究的目的:
- 合成和描述34种来自对称[FeIII(R-sal2232) ]+和不对称[FeIII(R-sal2223) ]+家族的新铁(III) 希夫基复合物.
- 研究分子对称性和结构扭曲对HS和LS状态稳定性的影响.
- 确定这些复合体中控制旋转交叉现象的关键因素.
主要方法:
- 对称和不对称的铁的合成 (III) 希夫基复合物.
- 磁测量以确定自旋状态和SCO行为.
- 通过X射线结晶学和光谱技术进行结构分析.
- 计算分析以评估HS和LS状态的相对能量.
主要成果:
- 对称复合体通常倾向于HS状态,少数呈现SCO. 不对称的复合体完全支持HS状态.
- [FeIII(5-I-sal2232) ]ClO4·1.5 在室温附近呈现热SCO.
- 分子对称性,特别是C2轴的存在,对于稳定LS状态至关重要.
- 在不对称复合体中增加的应变会导致更大的扭曲,阻碍LS状态稳定.
- 计算研究证实了不对称复合体中较高的HS状态稳定性,以及对称复合体中SCO的小HS-LS能量差距.
结论:
- 分子对称性是决定铁(III) 希夫基复合体中自旋状态偏好和SCO行为的主导因素.
- C2轴的存在与LS状态的稳定有很强的相关性.
- 由连接体不对称性引起的结构扭曲显著阻碍了LS状态的形成.
- 希夫基联体的理性设计可以用于调整铁 (III) 复合体的旋转交叉特性,以满足潜在的应用.
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