Two different faces of the triangular cluster Rh3Cp3(μ2-CO)3 towards metalloelectrophiles: Structural and theoretical study

The tetrahedral clusters [(C4Me4)CoRh3Cpʹ3(μ3-CO)3]+ (2; Cpʹ = C5H4Me) and [(Ph3P)AuRh3Cpʹ3(μ2-CO)3]+ (3) were synthesized by reactions of Rh3Cpʹ3(μ2-CO)3 (1b) with metalloelectrophiles [(C4Me4)Co]+ (generated from [(C4Me4)Co(C6H6)]+ under visible-light irradiation) and [(Ph3P)Au]+ (generated from (Ph3P)AuCl/Tl+). They were isolated as salts with PF6− anion, and the structures of 2PF6 and 3PF6 were determined by X-ray diffraction. The structural data gave evidence that the coordination of [(C4Me4)Co]+ occurs to the face of 1b with the CO ligands, while the [(Ph3P)Au]+ species reacts with the opposite face of 1b. The latter interaction is accompanied by elongation of the Rh–Rh bonds within the rhodium triangle by 0.1 Å. DFT calculations (at the BP86/TZP level) revealed that the selectivity of the metalloelectrophile coordination is determined by orbital control. © 2020 Elsevier B.V

Cyclooctadiene iridium complexes [Cp*Ir(COD)X]+ (X = Cl, Br, I): Synthesis and application for oxidative coupling of benzoic acid with alkynes

The cyclooctadiene iridium complexes [Cp*Ir(COD)X]PF6 ([1a−c]PF6; X = Cl, Br, I) were synthesized by reactions of Cp*Ir(COD) with halogens followed by a counterion exchange. The cyclooctadiene in these complexes is a thermally labile ligand. Complex [1b]PF6 reacts with trimethylphosphite to give [Cp*Ir{P(OMe)3}2Br]PF6 ([2]PF6) as a result of the cyclooctadiene replacement. The refluxing of [1b]PF6 in 1,2-dichloroethane affords the dimeric iodide [Cp*IrI2]2. The structures of [1b]PF6, [2]PF6 and [Cp*IrI2]2 were determined by X-ray diffraction. The Ir–COD bonding in [1a−c]+ and the related non-methylated complexes was analyzed by energy decomposition analysis. In the presence of silver salts, complexes [1a−c]PF6 (at 2.0 mol % loading) catalyze the oxidative coupling of benzoic acid with 1-phenyl-1-propyne in methanol at 60 °C to selectively give 4-methyl-3-phenylisocoumarin (3) or with diphenylacetylene in o-xylene at 160 °C to afford 1,2,3,4-tetraphenylnaphthalene (4). © 2018 Elsevier B.V

Cyclooctadiene iridium complexes [Cp*Ir(COD)X]+ (X = Cl, Br, I): Synthesis and application for oxidative coupling of benzoic acid with alkynes

The cyclooctadiene iridium complexes [Cp*Ir(COD)X]PF6 ([1a−c]PF6; X = Cl, Br, I) were synthesized by reactions of Cp*Ir(COD) with halogens followed by a counterion exchange. The cyclooctadiene in these complexes is a thermally labile ligand. Complex [1b]PF6 reacts with trimethylphosphite to give [Cp*Ir{P(OMe)3}2Br]PF6 ([2]PF6) as a result of the cyclooctadiene replacement. The refluxing of [1b]PF6 in 1,2-dichloroethane affords the dimeric iodide [Cp*IrI2]2. The structures of [1b]PF6, [2]PF6 and [Cp*IrI2]2 were determined by X-ray diffraction. The Ir–COD bonding in [1a−c]+ and the related non-methylated complexes was analyzed by energy decomposition analysis. In the presence of silver salts, complexes [1a−c]PF6 (at 2.0 mol % loading) catalyze the oxidative coupling of benzoic acid with 1-phenyl-1-propyne in methanol at 60 °C to selectively give 4-methyl-3-phenylisocoumarin (3) or with diphenylacetylene in o-xylene at 160 °C to afford 1,2,3,4-tetraphenylnaphthalene (4). © 2018 Elsevier B.V

New Method for the Synthesis of 1-Substituted (3a,6a)-Diaryl­glycolurils

A new approach has been developed for the synthesis of 1-substituted 3а,6а-diarylglycolurils from an imidazolone, imidazo­oxazolone, imidazooxazinone, or imidazooxazepinone and urea in the presence of hydrochloric acid. The structure of 1-ethyl-3а,6а-diphenylglycoluril was confirmed by X-ray diffraction studies. © Georg Thieme VerlagStuttgart · New York

New Method for the Synthesis of 1-Substituted (3a,6a)-Diaryl­glycolurils

A new approach has been developed for the synthesis of 1-substituted 3а,6а-diarylglycolurils from an imidazolone, imidazo­oxazolone, imidazooxazinone, or imidazooxazepinone and urea in the presence of hydrochloric acid. The structure of 1-ethyl-3а,6а-diphenylglycoluril was confirmed by X-ray diffraction studies. © Georg Thieme VerlagStuttgart · New York

The first example of mechanochemical synthesis of organometallic pincer complexes

The synthesis of an organometallic PdII pincer complex is realized for the first time via C[sbnd]H bond activation of the bis(thiocarbamate) ligand with PdCl2(NCPh)2 under mechanochemical conditions either by grinding of the reactants in a mortar or in a vibration ball mill at gram scale. © 2017 Elsevier B.V

Usage of (C5R5)Co(CO)I2 (R = H, Me) for the synthesis of 12-vertex closo-cobaltacarboranes. Unexpected formation of 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9

A series of 12-vertex closo-cobaltacarboranes 1,2-Rʹ2-3-(C5R5)-3,1,2-CoC2B9H9 (1a: R = Rʹ = H; 1b: R = Me, Rʹ = H; 2a: R = H, Rʹ = Me; 2b: R = Rʹ = Me) were synthesized by reactions of the carbonyl cobalt complexes (C5R5)Co(CO)I2 with Tl[Tl(η-7,8-Rʹ2-7,8-C2B9H9)]. The reaction of CpCo(CO)I2 with Tl[Tl(η-7,8-Me2-7,8-C2B9H9)] is accompanied by side formation of the novel charge-compensated nido-carborane 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9 (3) in 19% yield. The structures of 2a,b and 3 were determined by X-ray diffraction. © 201

Usage of (C5R5)Co(CO)I2 (R = H, Me) for the synthesis of 12-vertex closo-cobaltacarboranes. Unexpected formation of 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9

A series of 12-vertex closo-cobaltacarboranes 1,2-Rʹ2-3-(C5R5)-3,1,2-CoC2B9H9 (1a: R = Rʹ = H; 1b: R = Me, Rʹ = H; 2a: R = H, Rʹ = Me; 2b: R = Rʹ = Me) were synthesized by reactions of the carbonyl cobalt complexes (C5R5)Co(CO)I2 with Tl[Tl(η-7,8-Rʹ2-7,8-C2B9H9)]. The reaction of CpCo(CO)I2 with Tl[Tl(η-7,8-Me2-7,8-C2B9H9)] is accompanied by side formation of the novel charge-compensated nido-carborane 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9 (3) in 19% yield. The structures of 2a,b and 3 were determined by X-ray diffraction. © 201

Half-sandwich complexes of group 9 metals with N,Nʹ-ligands for CF3-carbenoid alkylation of N-(pyrimidin-2-yl)indole

The complexes [CpM(N,Nʹ-ligand)Br]PF6 (M = Rh, Ir; N,Nʹ-ligand = 2,2′-bipyridyl, 1,10-phenanthroline) were synthesized by reactions of bromides [CpMBr2]n with 2,2′-bipyridyl or 1,10-phenanthroline followed by a counterion exchange. The replacement of cyclooctadiene in [CpIr(cod)I]I3 with N,Nʹ-ligands leads to complexes [CpIr(N,Nʹ-ligand)I]I3 (N,Nʹ-ligand = 2,2′-bipyridyl, 1,10-phenanthroline). The structures of [CpRh(2,2′-bipyridyl)Br]PF6, [CpIr(2,2′-bipyridyl)I]I3, and [CpIr(1,10-phenanthroline)Br]PF6 were determined by X-ray diffraction. The compounds prepared as well as the related the tris(pyrazolyl)borate derivatives [CpCoTp]PF6 and [Cp*MTp]PF6 (M = Rh, Ir) efficiently catalyze the alkylation of N-(pyrimidin-2-yl)indole with methyl 3,3,3-trifluoro-2-diazopropionate to selectively introduce the CF3 and carboxylate functions at the C3 position of the indole moiety. In contrast, the tris(pyrazolyl)borate cobalt complex [Cp*CoTp]PF6 predominantly provides the alkylation at the C2 position. © 2021 Elsevier B.V