High-Oxidation-State 3d Metal (Ti–Cu) Complexes withN-Heterocyclic Carbene Ligation

Abstract

High-oxidation-state 3d metal species have found a wide range of applications in modern synthetic chemistry and materials science. They are also implicated as key reactive species in biological reactions. These applications have thus prompted explorations of their formation, structure, and properties. While the traditional wisdom regarding these species was gained mainly from complexes supported by nitrogen- and oxygen-donor ligands, recent studies with N-heterocyclic carbenes (NHCs), which are widely used for the preparation of low-oxidation-state transition metal complexes in organometallic chemistry, have led to the preparation of a large variety of isolable high-oxidation-state 3d metal complexes with NHC ligation. Since the first report in this area in the 1990s, isolable complexes of this type have been reported for titanium(IV), vanadium(IV,V), chromium(IV,V), manganese(IV,V), iron(III,IV,V), cobalt(III,IV,V), nickel(IV), and copper(II). With the aim of providing an overview of this intriguing field, this Review summarizes our current understanding of the synthetic methods, structure and spectroscopic features, reactivity, and catalytic applications of high-oxidation-state 3d metal NHC complexes of titanium to copper. In addition to this progress, factors affecting the stability and reactivity of high-oxidation-state 3d metal NHC species are also presented, as well as perspectives on future efforts.

Recent Advances in Iron‐Catalyzed C—H Bond Amination via Iron Imido Intermediate

“…On this end, there has been great and continuing effort to unravel the mysterious chemistry of iron imido species. [93][94][95][96][97] A large body of iron imido complexes are found capable of performing H-abstraction reaction toward C-H bonds, but many of the reactions fail to give C-N bond-formation products. [98][99][100][101][102][103][104][105][106][107] Therefore, factors effecting C-N bond formation are worth exploring.…”

Mercury(II) Complexes of Anionic N-Heterocyclic Carbene Ligands: Steric Effects of the Backbone Substituent

“…During the past three decades, considerable attention has been given to the chemistry of metal complexes of N-heterocyclic carbenes [1][2][3][4][5][6][7][8][9]. N-heterocyclic carbenes are versatile ligands with extensive applications in coordination chemistry and catalysis, as well as in bioinorganic chemistry [10][11][12][13][14][15][16][17].…”

Employing Aryl‐Linked Bis‐mesoionic Carbenes as a Pincer‐Type Platform to Access Ambient‐Stable Palladium(IV) Complexes

“…The very successful pincer frameworks have assisted the isolation of a number of reactive high‐valent metal species . For instance, van Koten et al.…”