Metal complexes containing silicon‐based pincer ligands: Reactivity and application in small molecule activation

Abstract

This review highlights the chemical properties of metal complexes supported by silicon-based tridentate ligands. Silicon donors coordinated to a metal exhibit unique characteristics such as a strong trans influence, σ-SiH interaction, and metal-ligand cooperativity. Thus, this type of donors ensures distinct reactivity toward various substrates. In particular, the σ-SiH interaction and mechanism of Si H bond cleavage are discussed. Several attempts to exploit silyl metal complexes for the activation of small molecules, including dinitrogen, carbon dioxide, dihydrogen, and dioxygen, have been reported. This review summarizes recently reported reactions of silyl pincer complexes with small molecules and provides new insights into the possibility of adapting silicon-based ligands to model the chemistry of biological catalytic systems.

X-type silyl ligands for transition-metal catalysis

“…17,29 The silyl groups acting as supporting ligands can significantly change or enhance the catalytic performance of metal complexes, especially in the case of bidentate and pincer forms. 25,27,29,[35][36][37][38][39] To date, reported examples included tridentate silyl ligands such as PSiP-type, SiOSi-type, NSiN-type, NNSitype, PSiSi-type, PNSi-type and SSiS-type, along with bidentate silyl ligands such as NSi-type, PSi-type, SSi-type and SiSi-type (Scheme 4).…”

Structure Effects of Ligands in Gold–Ligand Complexes for Controlled Formation of Gold Nanoclusters

“…It is noteworthy that the various Au I –ligand complexes have different reactivity toward reductive conversion according to the coordination of Au I in the complexes. , In addition, the process of the second step is complicated. In many cases of Au NC synthesis, Au NCs of the desired size are generated after sequential transformations from complexes to a series of small Au NCs with gradually increasing sizes. ,, Thus, to understand the complicated Au NC formation process and synthesize the desired Au NCs with high uniformity, it is essential to understand the reactivity of the complexes toward reduction. , …”

“…38,39,41 Thus, to understand the complicated Au NC formation process and synthesize the desired Au NCs with high uniformity, it is essential to understand the reactivity of the complexes toward reduction. 42,43 Among several factors influencing the reactivity of the complexes, ligand structure is of primary importance as ligands directly coordinate with and protect Au I in the complexes. 35,44 The ligand, which is normally used in Au NC synthesis, is composed of the anchoring part that directly binds to Au atoms (e.g., S and P atoms in thiol and phosphine ligands, respectively) and carbon bodies such as aliphatic chains or aromatic rings.…”

Cooperation towards nobility: equipping first-row transition metals with an aluminium sword

“…[28][29][30] Pairing base metals with heavier neighbours from group 14 is an approach that has been gaining increased interest recently, [31][32][33][34] as weaker bonding after activation with such elements promotes small molecule activation in an efficient and synergistic manner. 35,36 A powerful alternative that has been recently exploited to overcome the reluctance of carbene-metal systems to undergo cooperative catalysis is the use of elements from group 13. [37][38][39] Such elements possess unoccupied p-orbitals, in both high-valent and low-valent states, and coordination of ligands to such orbitals appears to be more labile, which facilitates bond scission and, subsequently, catalysis.…”