在气相中的七坐标均质金属碳酸
Allen M Ricks1, Zach D Reed, Michael A Duncan
1Department of Chemistry University of Georgia, Athens, Georgia 30602, USA.
Journal of the American Chemical Society
|June 16, 2009
概括
使用红外光谱学研究了基组金属碳酸. 研究人员确定了协调数,发现V ((CO) 6 ((+),Nb ((CO) 6 ((+) 和Nb ((CO) 7 ((+),Ta ((CO) 7 ((+)) 结构,与理论预测不同.
科学领域:
- 无机化学 无机化学
- 物理化学 物理化学
- 频谱学是一种光谱学.
背景情况:
- 金属碳化合物复合物在催化和有机金属化学中至关重要.
- 了解早期过渡金属的协调化学是非常重要的.
- 气相研究提供了关于固有的结合和结构的见解,没有溶剂效应.
研究的目的:
- 为了确定瓦纳组金属碳酸 (V+,Nb+,Ta+) 的协调数和结构.
- 为了研究不同金属碳烯物种的气相稳定性和形成偏好.
- 将实验结果与密度函数理论 (DFT) 的理论预测进行比较.
主要方法:
- 在分子束中使用激光蒸发生产金属碳酸.
- 使用飞行时光谱测量进行质量分析和尺寸选择.
- 红外 (红外) 激光光分离光谱检测碳基拉伸频率.
- 密度函数理论 (DFT) 计算用于光谱预测和结构分析.
主要成果:
- (V+) 主要形成了六坐标V ((CO) 6 ((+),而不是预测的七坐标物种.
- (Nb+) 产生了六坐标Nb(CO) 6 ((+) 和七坐标Nb ((CO) 7 ((+) 复合体.
- (Ta+) 完全形成了七坐标的Ta ((CO) 7 ((+) 复合体.
- 实验性IR光谱显示了六和七坐标结构之间的明显差异,与DFT预测很好地对齐.
结论:
- 对于V+,Nb+和Ta+对CO的协调偏好有很大的不同.
- V ((CO) 6 ((+)) 和Nb ((CO) 6 ((+)) 采用略有扭曲的八面体结构.
- Nb ((CO) 7 ((+)) 和 Ta ((CO) 7 ((+)) 呈现出C3v顶顶的八面体几何形状.
- DFT计算是预测和解释这些金属碳酸的红外光谱的可靠工具.
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