Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
Nat Chem. 2013 Feb;5(2):115-21. doi: 10.1038/nchem.1520. Epub 2012 Dec 9.
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 π-diborene complex in which an electron-rich group 10 metal donates electrons into an empty bonding π 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.
过渡金属催化的基础原理是金属向配体提供电子，被配体的反键轨道接受，从而削弱配体中的一个键。没有这个原理，许多催化过程中键的初始活化步骤根本不会发生。这一概念被收入广为接受的过渡金属键的 Dewar-Chatt-Duncanson 模型。本文提供了第一个真正违反 Dewar-Chatt-Duncanson 成键模型的实验和计算证据，该模型存在于一个π-二硼烯配合物中，富电子的第 10 族金属将电子提供给配体的空键π轨道，从而增强了键。该配合物也是第一个含有配位二硼烯的过渡金属配合物，这种物质以前无论是游离态还是与金属配位态都没有被分离出来过。
