Interaction of 2-(arylazo)phenols with rhodium. Usual coordination vs. C–H and C–C activation

Rhodium complexes of 1,3-diaryltriazenes: Usual coordination, N–H bond activation and, N–N and C–N bond cleavage

“…This distortion is particularly attributable to the strain imposed by formation of the four-membered chelate rings with relatively small bite angles (61.5(4)°and 58.8(3)°) by the triazene ligands. The Rh-P and Rh-C distances are all quite normal, and so are the Rh-N distances [2][3][4][5]9,12], except the Rh(1)-N(1B) distance, which is slightly longer than usual. The observed elongation of the Rh(1)-N(1B) bond, which is trans to the Rh(1)-C(1C) bond, may be due to the trans effect of the coordinated 4-methylphenyl fragment [43][44][45].…”

“…Reactions of the 1,3-diaryltriazenes with [Rh(PPh 3 ) 3 Cl] has been carried out in refluxing ethanol in the presence of triethylamine [41], which have afforded a family of yellow complexes [42] (1-R, Chart 1) in decent yields. Preliminary (microanalytical and spectroscopic) characterizations on these complexes, although gave some idea about their composition, failed to indicate any definite formulation for them.…”

“…[Rh(PPh 3 ) 3 Cl], is famous for its catalytic application in bringing about numerous interesting chemical transformations [1], we have found it to be a useful synthon for the preparation of mixed-ligand complexes of various types [2][3][4][5][6][7][8][9][10][11][12][13]. Besides its demonstrated ability to accommodate new ligands, it has also been found to mediate many interesting reactions, such as C-H and C-C bond activation of organic molecules [2,5,9,12], activation of molecular oxygen [13], and transformation of coordinated ligands [5,9,11].…”

“…The chemistry of the triazene ligands is further important because of their biological relevance [38][39][40]. Reaction of 1,3-diaryltriazenes (L) with [Rh(PPh 3 ) 3 Cl] has indeed afforded complexes containing g 2 -bound triazenes (I), but depending on the nature of the reaction medium interesting N-N and C-N bond cleavage of the 1,3-diaryltriazenes also has taken place affording organorhodium complexes having g 1 -bound aryl fragment. The present report deals with the chemistry of all these complexes with special reference to their formation, structure and spectral and electrochemical properties.…”

Interaction of 2-(2′,6′-dialkylphenylazo)-4-methylphenols with iridium. C–H activation and migration of alkyl group

“…Metal promoted C-H and C-C bond activation of organic molecules has thus been of significant current interest [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. We have been active, for quite some time, in the synthesis of organometallic complexes via platinum-group metal mediated C-H bond activation of organic ligands in general [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] and of 2-(arylazo)-4-methylphenols (I) in particular [44][45][46][47][48][49], and the present work has emerged from our continued interest in this area. In this study iridium has been selected as the platinum-group metal for promoting C-H or C-C bond activation and [Ir(PPh 3 ) 3 Cl] has been utilized as the iridium starting material.…”