| 一维[Pd(mnt)2]-自旋体系磁交换作用的密度泛函理论(DFT)分析(英文) |
| Observation of Strongly Antiferromagnetic Exchange Interactions in Four Quasi-One-Dimensional Bis(maleonitriledithiolato) Palladate Monoanion Spin Systems: an Insight from DFT Calculation |
|
| 摘要: 4个一维磁链化合物[R-BzPy][Pd(mnt)2](R-BzPy+=对位取代苄基吡啶阳离子；R=Cl(化合物1)，Br(化合物2)，I(化合物3)和NO2(化合物4))具有相似的晶体堆积结构，即，[Pd(mnt)2]-和R-BzPy+分别形成完全分列的柱状堆积。这一结构特征与其类似化合物[R-BzPy][Ni(mnt)2]相似。但是，[Pd(mnt)2]-和[Ni(mnt)2]- 2个系列化合物结构之间存在明显差异：(1)室温下，[R-BzPy][Ni(mnt)2]晶体中[Ni(mnt)2]-和R-BzPy+堆积柱是均匀的；而[R-BzPy][Pd(mnt)2]晶体中[Pd(mnt)2]-和R-BzPy+堆积柱是不均匀的。(2)在两个系列化合物阴离子堆积柱内，相邻[Pd(mnt)2]-分子平面之间距离比相邻[Ni(mnt)2]-分子平面之间距离短。在[Pd(mnt)2]-堆积柱内，[Pd(mnt)2]-离子之间反铁磁交换作用非常强，导致了化合物几乎呈抗磁性。在密度泛函理论框架下，利用对称性破损方法，我们计算了[Pd(mnt)2]-离子之间磁交换常数。在svwn/lanl2dz和bpw91/lanl2dz水平上的计算结果与磁化率拟合结果一致。理论分析揭示，在[Pd(mnt)2]-堆积柱内，[Pd(mnt)2]-离子之间强反铁磁交换与其π-型前线轨道有效重叠密切相关。 |
| 关键词: Bis(maleonitriledithiolato)palladate monoanion 磁性 DFT 对称性破损 |
| 基金项目: |
| Abstract: Four quasi-one-dimensional (quasi-1D) compounds consist of bis(maleonitriledithiolato)palladate monoanions ([Pd(mnt)2]-) with benzylpyridinium derivatives (R-BzPy+, where R represents the substituent in the para-site of the phenyl ring; R=Cl, Br, I and NO2 for 1~4, respectively), which show similar stacking structures to the [Ni(mnt)2]- analogues. The [Pd(mnt)2]- and R-BzPy+ ions form the segregated stacks, each stack is surrounded by four counterion stacks. In comparison of [Pd(mnt)2]- with [Ni(mnt)2]- analogues, the structural distinctions involving both anion and cation stacks are regular for [Ni(mnt)2]- series; while irregular for [Pd(mnt)2]- analogues at room temperature. The inter-plane distances are shorter in [Pd(mnt)2]- than those in [Ni(mnt)2]- stack. There exist strongly antiferromagnetic (AFM) interactions in [Pd(mnt)2]- stack, which magnetic exchange constants are evaluated via broken-symmetry approach in DFT framework, and the calculated results at svwn/lanl2dz and bpw91/lanl2dz levels are parallel to the experimental results, disclosing that the strongly AFM interactions is due to larger overlap of π-type frontier molecular orbitals. |
| Keywords: bis(maleonitriledithiolato)palladate monoanion magnetic property density functional theory broken-symmetry |
| |
| 摘要点击次数: 1483 |
| 全文下载次数: 1395 |
| 张 辉,陈选荣,任小明,孟庆金.一维[Pd(mnt)2]-自旋体系磁交换作用的密度泛函理论(DFT)分析(英文)[J].无机化学学报,2011,27(12):2464-2472. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
| Support information: |
|
|
|
|
|
|
