二的最小能量结构 ((pyrazolyl) 二 ((V) 四化物不是一个C ((3upsilon) 封顶的八面体
C E Webster1, D A Singleton, M J Szymanski
1Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
Journal of the American Chemical Society
|October 5, 2001
概括
计算研究揭示了四化物复合物的新结构,挑战了以前的解释,并提供了对它们的反应性的见解. 这些发现有助于理解这些重要的有机金属化合物的动态.
科学领域:
- 无机化学 无机化学
- 计算化学计算化学
- 有机金属化学 有机金属化学
背景情况:
- 中性四化物复合物,特别是三 (((pyrazol-1-yl) borato四 (TpIrH (((4)) 和其甲基化模拟物 (Tp*IrH ((4)),已被合成和描述.
- 之前对实验数据的解释表明,这些复合体具有面顶八面体结构 (C(3upsilon)).
研究的目的:
- 使用先进的计算方法研究TpIrH的结构景观.
- 重新评估拟议的C ((3upsilon) 结构,并确定替代稳定或超稳定几何体.
- 将计算发现与实验光谱数据 (NMR和IR) 相关联.
主要方法:
- 密度函数理论 (DFT) 几何优化被用来探索潜在能量表面.
- 结合集群计算被用于更准确的能源评估.
- 为了描述静止点和模拟振动光谱,进行了波频率计算.
主要成果:
- 之前提出的C(3upsilon) 结构被确定为过渡状态 (局部最大值),而不是稳定的最小值.
- 发现了两个新的低能结构,一个C(s) 边缘桥接的八面体四化物和一个C(1) eta(2) -二,二化物同位素,是局部最小值.
- 连接这些最小值的低能量过渡状态被发现,这表明易于相互转换.
- 对于C(s) 和C(1) 结构的计算NMR光谱与实验数据相匹配.
- 计算和实验红外光谱的比较进一步支持了C(s) 和C(1) 结构的赋值.
结论:
- 面顶八面体结构不太可能是TpIrH的基本状态或显著贡献者.
- 结构C ((s) 和C ((1) 代表了实验观察到的TpIrH ((4) 的形式.
- 计算模型为了解四化物复合物的流动性行为和反应性提供了一个强大的框架.
更多相关视频
06:35Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
11:44Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
相关概念视频
Exceptions to the Octet Rule
Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:
VSEPR Theory and the Basic Shapes
Overview of VSEPR Theory
VSEPR Theory and the Effect of Lone Pairs
Effect of Lone Pairs of Electrons on Molecule Geometry
Predicting Molecular Geometry
VSEPR Theory for Determination of Electron Pair Geometries
VSEPR Theory
Valence shell electron-pair repulsion theory (VSEPR theory) enables us to predict the molecular structure around a central atom from an examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement that minimizes repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom form either bonding...
Structure of Benzene: Molecular Orbital Model
According to the molecular orbital (MO) model, benzene has a planar structure with a regular hexagon of six sp2 hybridized carbons. As shown in Figure 1, each carbon is bonded to three other atoms with C–C–C and H–C–C bond angles of 120°. The C–H bond length is 109 pm, and the C–C bond length is 139 pm which is midway between the single bond length of sp3 hybridized carbons (154 pm) and sp2 hybridized carbons (133 pm).
