Formation of organorhodium complexes via C–H bond activation of 1,3-di(phenylazo)benzene

Abstract

Reaction of a potential NCN-pincer ligand, viz. 1,3-di(phenylazo)benzene (L), with [Rh(PPh(3))(3)Cl] affords, via a C-H bond activation, an interesting dinuclear Rh(II) complex (1), and with RhCl(3)·3H(2)O affords a mononuclear Rh(III) complex (2) containing a catalytically useful Rh-OH(2) fragment.

Redox Noninnocent Azo-Aromatic Pincers and Their Iron Complexes. Isolation, Characterization, and Catalytic Alcohol Oxidation

“…The coordinated azo ligand is redox active and produces an azo anion radical upon reduction; − therefore, to check the involvement of ligand-centered redox as well as to confirm the formation of any organic radicals during catalytic turnover, the catalytic reaction was performed in the presence of a radical inhibitor. When an equivalent amount of TEMPO was added to the reaction system, the yield of the reaction decreased drastically (Table , entry 32).…”

“…On the other hand, Goswami and co-workers extensively studied the chemistry of 2-(arylazo)­pyridine and related ligand systems . A few other groups also studied the coordination chemistry of some further azo-aromatic ligands . However, unlike with the diamine/aminophenol ligand systems, the chemistry with redox-active azo-aromatics has been mainly limited to studies of structure–bonding relationships. − There are only a few reports or attempts known where azo-aromatic ligands were exploited to perform catalytic reactions utilizing the redox-active nature of the azo chromophore.…”

“…A few other groups also studied the coordination chemistry of some further azo-aromatic ligands . However, unlike with the diamine/aminophenol ligand systems, the chemistry with redox-active azo-aromatics has been mainly limited to studies of structure–bonding relationships. − There are only a few reports or attempts known where azo-aromatic ligands were exploited to perform catalytic reactions utilizing the redox-active nature of the azo chromophore. Recently, in a seminal work Goswami and co-workers reported the synthesis of the tridentate azo-aromatic pincer 2,6-bis­(phenylazo)­pyridine, and they have successfully used its nickel complexes for catalytic alcohol oxidation reactions where the azo-aromatic ligand acts as an electron reservoir during catalytic turnover …”

Rhodium and Iridium Mediated C-H and O-H Bond Activation of Two Schiff Base Ligands: Synthesis, Characterization and Catalytic Properties of the Organometallic Complexes

“…The chemistry of rhodium and iridium has been receiving considerable current attention ( Chi et al, 2017 ; Colombo et al, 2020 ; Mao et al, 2020 ; Shaikh et al, 2020 ; Alsalahi and Trzeciak, 2021 ; Davison et al, 2021 ; Monti et al, 2021 ; Vuuren et al, 2021 ), largely because of the interesting properties exhibited by the complexes of these metals. As properties of the complexes are dictated primarily by the coordination environment around the metal center, complexation of rhodium by ligands of selected types has been of significant importance, and the present work has originated from our interest in this area ( Dutta et al, 2000a ; Dutta et al, 2000b ; Das et al, 2002 ; Dutta et al, 2002 ; Acharyya et al, 2004a ; Acharyya et al, 2004b ; Acharyya et al, 2005 ; Acharyya et al, 2006 ; Basu et al, 2006 ; Baksi et al, 2007a ; Basu et al, 2007 ; Baksi et al, 2007b ; Dasgupta et al, 2008 ; GuhaRoy et al, 2008 ; Acharyya et al, 2009 ; GuhaRoy et al, 2009 ; Baksi et al, 2010 ; Basu et al, 2010 ; Majumder et al, 2011 ; Seth and Bhattacharya, 2011 ; Bhattacharya et al, 2012 ; Paul and Bhattacharya, 2012 ; Sengupta and Bhattacharya, 2013 ; Paul et al, 2014 ). Herein we have selected two Schiff base ligands, viz .…”

Coordination chemistry of Co complexes containing tridentate SNS ligands and their application as catalysts for the oxidation of n-octane

“…Hence, there are only a handful of reported examples on the utilization of pincer ligand-based metal complexes for the catalytic activation of mainly aryl and vinyl C-H bonds. 2,[12][13][14][15][16][17][18][19][20][21][22][23] Since their discovery in the mid-1970s, pincer-type ligands have become increasingly important in chemistry, 24 and owing to their ability to tailor the reactivity, selectivity and stability of the ligands towards a specific reaction pathway or product, the application of pincer-based metal complexes has dramatically increased. 18,[25][26][27] These advantages are due to the terdentate binding mode of the ligands which implies that they are able to stabilize metal centers more effectively than related mono or bidentate variants.…”