Bond-strengthening π backdonation in a transition-metal π-diborene complex
Bond-strengthening π backdonation in a transition-metal π-diborene complex
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DOI：
10.1038/nchem.1520
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发表时间：
2013-02-01
期刊：
影响因子：
21.8
通讯作者：
Vargas, Alfredo
中科院分区：
文献类型：
--
作者：
Braunschweig, Holger;Damme, Alexander;Vargas, Alfredo
过渡金属催化是建立在这样的原理上的：从金属到配体的电子捐赠被配体的反键轨道接受，从而削弱配体中的一个键。没有这个，在许多催化过程中键活化的初始步骤就不会发生。这一概念被广泛接受的Dewar-Chatt-Duncanson过渡金属成键模型所体现。我们在此提出的实验和计算证据的第一个真正违反的杜瓦-查特-邓肯森键合模型，发现在一个π-diborene复合物中，其中一个富电子的第10族金属捐赠电子到一个空的键合π轨道上的配体，从而加强了键。该配合物也是第一个含有结合二硼烯的过渡金属配合物，这种物质以前没有分离出来，无论是以自由形式还是与金属结合。
Transition-metal catalysis is founded on the principle that electron donation from a metal to a ligand is accepted by an antibonding orbital of the ligand, thereby weakening one of the bonds in the ligand. Without this, the initial step of bond activation in many catalytic processes would simply not occur. This concept is enshrined in the well-accepted Dewar-Chatt-Duncanson model of transition-metal bonding. We present herein experimental and computational evidence for the first true violation of the Dewar-Chatt-Duncanson bonding model, found in a pi-diborene complex in which an electron-rich group 10 metal donates electrons into an empty bonding pi orbital on the ligand, and thereby strengthens the bond. The complex is also the first transition-metal complex to contain a bound diborene, a species not isolated before, either in its free form or bound to a metal.