Mechanisms of intramolecular activation of carbon-hydrogen bonds in transition-metal complexes

Cyclometalation Using d-Block Transition Metals: Fundamental Aspects and Recent Trends

“…Similarly, the introduction of donor substituents at the arene has been successfully demonstrated to promote cyclometalations proceeding through an electrophilic C aryl -H bond activation process. 39,40 Steric congestion in the metal coordination sphere may constitute another driving force for inducing C-R bond activation. For example, numerous C-H bond activation processes have been observed in tBu groups, and related C-H bonds that are confined in close proximity to the metal center.…”

“Rollover” cyclometalation – early history, recent developments, mechanistic insights and application aspects

“…9) exist, i.e. bidentate N,C(3)-coordination (23), monodentate N-coordination (24), monodentate, covalent M-C(3) linkage (25) and bidentate N,S-coordination (26 126 the latter compound is an especially interesting example because it combines both motifs 23 and 24 within one single complex.…”

“…Common to the otherwise different approaches, such as directed ortho-metalation, 4 remote functionalization, [5][6][7][8][9][10][11][12][13][14] or cyclometalation, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] is the precoordination of the substrate to a metal center, followed by the activation of geometrically accessible C-H bonds, which can be adjacent or remote, to generate a template for further functionalization. In particular, cyclometalation has attracted much attention and, not surprisingly, formed the subject of several review articles.…”

Synthesis of rhodium(III) complexes with tris/tetrakis‐benzimidazoles and benzothiazoles—quick identification of cyclometallation by nuclear magnetic resonance spectroscopy

“…[1] Lonnon et al [2] have reported the X-ray crystal structure and NMR study of the catalytically active rhodium(III) complex with N 4 -tripodal ligand, tris(2-benzimidazolylmethyl)amine. Other studies have illustrated how tripodal (N-heterocyclic alkyl)amine ligand design influences the geometry of the complexes and the internal exchange processes between isomers.…”