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• 79-37-8 oxalyl dichloride 
• 1199-46-8 2-amino-4-tert-butylphenol 

Relevant academic research and scientific papers

Iridium(I) and iridium (III) complexes supported by a diphenolate imidazolyl-carbene ligand

Deprotonation of l,3-di(2-hydroxy-5-tert-butylphenyl)imidazolium chloride (la) followed by reaction with chloro-l,5-cyclooctadiene Ir(I) dimer affords the anionic Ir(I) complex [K][{OCO}Ir(cod)] (2: OCO = l,3-di(2-hydroxy-5-tert- butylphenyl)imidazolyl; cod = 1,5-cyclooctadiene), the first Ir complex stabilized by a diphenolate imidazolyl-carbene ligand. In the solid state 2 exhibits squareplanar geometry, with only one of the phenoxides bound to the metal center. Oxidation of 2 with 2 equiv of [FeCp2][PF6] generates the Ir(III) complex [{OCO}Ir(cod)(MeCN)][PF6] (3). Reaction of 3 with H2 results in the liberation of cyclooctane and a species capable of catalyzing the hydrogenation of cyclohexene to cyclohexane. Displacement of cyclooctadiene from 3 can be achieved by heating in acetonitrile to form [{OCO}Ir(MeCN)3][PF6] (4) or by reaction with either PMe3 or PCy3 to generate [{OCO}Ir(PMe 3)3][PF6] (5) or [{OCO}Ir(PCy3) 2(MeCN)][PF6] (6), respectively. 6 reacts with CO in acetonitrile to give an equilibrium mixture of 6 and [{OCO}Ir(PCy 3)2(CO)][PF6] (7) and with chloride to generate [{OCO}Ir(PCy3)2Cl] (8). The solid-state structure of 8 shows that the diphenolate imidazolylcarbene ligand is distorted from planarity; DFT calculations suggest this is due to an antibonding interaction between the phenolates and the metal center in the highest occupied molecular orbital (HOMO) of the complex. 8 undergoes two successive reversible one-electron oxidations in CH2Cl2 at -0.22 and at 0.58 V (vs ferrocene/ ferrocenium); EPR spectra, mass spectroscopy, and DFT calculations suggest that the product of the first oxidation is [{OCO}Ir(PCy3) 2Cl]+ (8+), with the unpaired electron occupying a molecular orbital that is delocalized over both the metal center and the diphenolate imidazolyl-carbene ligand.

Three-center intramolecular hydrogen bonding in oxamide derivatives. NMR and X-ray diffraction study

This contribution describes the synthesis and structural investigation of the symmetric and non-symmetric oxamides N,N′-bis(2-hydroxyphenyl)oxamide 1, N,N′-bis(5-tert-butyl-2-hydroxyphenyl)-oxamide 2, N,N′-bis(3,5-dimethyl-2-hydroxyphenyl)oxamide 3, N,N′-bis(2-hydroxybenzyl)oxamide 4, N,N′-diphenethyloxamide 5, N-(2-hydroxyphenyl)-N′-(2-methoxyphenyl)oxamide 6, N-(2-hydroxy-phenyl)-N′-phenethyloxamide 7, (1S,2R)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl)norephedrine 8, (1R,2S)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl) 9, ethyl N-(2-hydroxyphenyl)oxalamate 10 and ethyl N-(2-methoxyphenyl)oxalamate 11. The structures were established by 1H, 13C, 15N and variable temperature NMR spectroscopy. Compounds 1-4 and 6-11 are stabilized by intramolecular three-center hydrogen bonding between the amide proton and two oxygen atoms. The 1H NMR Δδ/ΔT value of the amide proton correlates with the 15N NMR chemical shift. The X-ray diffraction molecular structures of 1 and 11 showed a planar conformation with trans configuration in the solid state, corresponding to the preferred conformation found in solution.