通过2,6-烯碳酸盐桥的MM四重键 (M = Mo或W) 的远程电子合
Mikhail V Barybin1, Malcolm H Chisholm, Naresh S Dalal
1Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045-7582, USA.
Journal of the American Chemical Society
|October 27, 2005
概括
这项研究报告了新的金属复合体,由阿祖伦基酸搭建桥梁,显示金属中心之间的独特电子合. 该研究详细介绍了它们的结构,电子性质和氧化形式的行为,揭示了电子脱和极化效应.
科学领域:
- 协调化学 协调化学
- 有机金属化学 有机金属化学
- 材料科学 材料科学 材料科学
背景情况:
- 研究了2,6-阿烯基碳酸及其二的合成和结构特征.
- 探讨了新型金属复合物的形成,这些复合物具有四重结合的M(2) 中心,由阿祖伦基碳酸联体构成桥梁.
研究的目的:
- 为了合成和表征新的蓝色碳酸盐桥接金属复合物.
- 为了研究两核金属中心 (M(2) 之间的电子合,由极性青碳酸桥介导.
- 通过各种光谱和电化学方法研究产生的复合物及其基离子的电子和磁性特性.
主要方法:
- 合成2,6-阿祖伦二碳酸及其二.
- 双碳酸与M(2)(O(2)C(t) Bu) ((4) 复合体 (M = Mo,W) 发生反应,形成桥接复合体.
- 用于结构确定的X射线晶体学.
- 紫外-对-红外和EPR光谱用于电子和磁性表征.
- 电化学研究 (循环电压测量).
- 密度函数理论 (DFT) 计算用于电子结构分析.
主要成果:
- 对M = Mo (III) 和W (IV) 的阿祖伦基碳酸盐桥梁复合物的隔离和结构阐明[M(2)(O(2)C(t) Bu) ((3)) ](2)(mu-2,6-(CO(2)) ((2)-C(10) H ((6).
- 在可见 (III) 和近IR (IV) 区域观察强烈的金属到桥梁电荷转移吸收.
- 通过一电子氧化生成和表征基离子III ((+) 和IV ((+)) 通过一电子氧化.
- 复合物III(+) 呈现价值陷行为 (II类),而复合物IV(+) 则显示单个电子在两个W(2) 中心的脱局,有极化证据.
- DFT计算显示,最高占成的分子轨道 (HOMO) 是M(2) 三角轨道的混合物,主要集中在一个M(2) 单元上,电子合通过桥梁pi系统发生.
结论:
- 蓝色碳酸盐桥有效地促进了双核金属中心之间的电子通信.
- 和复合体之间的电子特性和合机制不同,受桥梁和金属特征的影响.
- 该研究提供了对桥梁金属复合体中电子转移和移位的见解,这与分子电子学和材料科学有关.
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