N‐(Aryl)picolinamide Complexes of Ruthenium: Usual Coordination and Strategic Cyclometalation

Abstract

Reaction of five N-(4-R-phenyl)picolinamides (R = OCH 3 , CH 3 , H, Cl, and NO 2 ) with [Ru(PPh 3 ) 2 (CO) 2 Cl 2 ] in refluxing 2-methoxyethanol in the presence of a base (NEt 3 ) affords two geometrical isomers of a group of complexes (1-R and 2-R), each of which contains an amide ligand coordinated to the metal center as a monoanionic bidentate N,N donor along with two triphenylphosphanes, a carbonyl, and a hydride. Similar reaction of N-(naphthyl)picolinamide with [Ru(PPh 3 ) 2 (CO) 2 Cl 2 ] affords an organometallic complex, 3, in which the amide ligand is coordinated to the metal center, by C-H activation of the naphthyl ring at the 8-position, as a dianionic tridentate N,N,C donor along with two triphenylphosphanes and one carbonyl. Structures of the 1-OCH 3 , 2-CH 3 , and 3 complexes have been determined by X-

Scope and Limitations of Auxiliary-Assisted, Palladium-Catalyzed Arylation and Alkylation of sp2 and sp3 C–H Bonds

“…This compound is known. 16 1 H NMR (400 MHz, CDCl 3 , ppm) δ 10.77 (s, 1H), 8.70 (d, J = 8.2 Hz, 1 H), 8.36 (d, J = 8.2 Hz, 1 H), 8.36 (d, J = 7.8 Hz, 1 H), 8.09 (d, J = 8.2 Hz, 1 H), 7.95–7.88 (m, 2 H), 7.70 (d, J = 8.2 Hz, 1 H), 7.61–7.50 (m, 4H).…”

Bis‐picolinamide Ruthenium(III) Dihalide Complexes: Dichloride‐to‐Diiodide Exchange Generates Single trans Isomers with High Potency and Cancer Cell Selectivity

“…The complexes were synthesised following the known procedure of Chan and co‐workers (see Scheme ), in which the group had previously reported complex 6 and assessed its potential as a catalyst for the epoxidation of cyclic alkenes. Bhattacharya and co‐workers have also synthesised similar complexes consisting of one or three picolinamide (L) ligands, [Ru(L)(PPh 3 )(H)(CO)] and [Ru(L) 3 ], respectively, in which the ligands are all bound (N,N) to the ruthenium metal centre . We report on halide exchange reactions to yield the diiodide complexes [RuI 2 (L) 2 ], which give single trans isomers, thus potentially minimising any future drug formulation issues, which may occur due to the presence of multiple isomers with different effects or potency.…”

“…Bhattacharya and coworkers have also synthesised similarc omplexes consisting of one or three picolinamide (L) ligands, [Ru(L)(PPh 3 )(H)(CO)] and [Ru(L) 3 ], respectively,i nw hich the ligandsa re all bound (N,N) to the ruthenium metal centre. [68,74] We report on halide exchange reactions to yield the diiodide complexes [RuI 2 (L) 2 ], which give single trans isomers, thus potentially minimising any future drug formulation issues, which may occur due to the presence of multiple isomers with different effects or potency.T hese complexesh ave been studied in both the solid state and in solution to identify the potentiali somers present. The trans isomers show surprisingly high cytotoxicity,w ith IC 50 values in the nanomolar range,a nd high selectivity towards cancer cells.…”

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.…”