Résultat de la recherche
Ru2(CO)4(OOCR)2L2 sawhorse-type complexes containing axial 5-(4-pyridyl)-10,15,20-triphenylporphyrin ligands
The thermal reaction of Ru3(CO)12 with various carboxylic acids (benzoic, 4-hydroxyphenylacetic, ferrocenic, stearic, oleic, 4-(octadecyloxy)benzoic) in refluxing tetrahydrofuran, followed by addition of 5-(4-pyridyl)-10,15,20-triphenylporphyrin (L), gives the dinuclear complexes Ru2(CO)4(OOCR)2L2 (1: R = –C6H5, 2: R = –CH2-p-C6H4OH, 3: R = –C5H4FeC5H5, 4: R = –(CH2)16CH3, 5: R = –(CH2)7CHdouble bond; length as m-dashCH(CH2)7CH3, 6: R = –p-C6H4O(CH2)17CH3). Complexes 1–6 were characterised by IR, NMR, and ESI-MS as well as by elemental analysis. The UV–Vis spectra show the Soret band centred at 417 nm and the Q bands at 515, 550, 590 and 645 nm, respectively.
Synthesis, structure and electrochemistry of cationic diruthenium complexes of the type [(N∩N)2Ru2 (CO)2 (μ-CO)2(μ-OOCFc)]+ containing a ferrocenecarboxylato bridge and two chelating aromatic diimine ligands
The dinuclear bis(ferrocenecarboxylato) complex Ru2 (CO)4 (μ-OOCFc)2 (py)2 (Fc = ferrocenyl, py = pyridine) was found to react with aromatic diimines (2,2′-dipyridyl, 4,4′-dimethyl-2,2′-dipyridyl, 1,10-phenanthroline, 5-nitro-1,10-phenanthroline, and 5-amino-1,10-phenanthroline) in methanol to give the cationic diruthenium complexes [(N∩N)2Ru2 (CO)2 (μ-CO)2(μ-OOCFc)]+ (1: N∩N = 2,2′-dipyridyl, 2: N∩N = 4,4′-dimethyl-2,2′-dipyridyl, 3: N∩N = 1,10-phenanthroline, 4: N∩N = 5-nitro-1,10-phenanthroline, 5: N∩N = 5-amino-1,10-phenanthroline), which have been isolated as the hexafluorophosphate salts. The molecular structure of 3, solved by single-crystal X-ray analysis of the tetraphenylborate salt [3][BPh4], shows a diruthenium backbone bridged by two carbonyl and by one ferrocenecarboxylato ligand, the two 1,10-phenanthroline ligands being in the axial positions. Cyclic voltammetry in dichloromethane reveals for all compounds two successive oxidations due to ferrocene/ferrocenium redox couple and oxidation of the diruthenium core.
An asymmetric trihydrido-bridged arene ruthenium complex
Reaction of [Ru(η6-indane)(H2O)3]2+ and [Ru(η6-C6Me6)(H2O)3]2+ with NaBH4 in water gives a mixture of three triple hydrido-bridged arene ruthenium cations [(η6-arene)Ru(μ-H)3Ru(η6-arene′)]+ (arene=indane and hexamethylbenzene; arene′=indane and hexamethylbenzene). After treatment with NaBF4, the three complexes are separated by column chromatography and the asymmetrical [(η6-indane)Ru(μ-H)3Ru(η6-C6Me6)][BF4] (cation 1a) can be isolated in moderate yield. 1a decomposes in solution to give the corresponding hydroxo-bridged complex [(η6-indane)Ru(μ-OH)3Ru(η6-C6Me6)]+ (2) with retention of the asymmetrical geometry as shown by single-crystal X-ray structure analysis. The indane ligand adopts an envelope conformation toward the ruthenium atom.
New Dinuclear Ru2(CO)4 Sawhorse-Type Complexes Containing Bridging Carboxylato Ligands
The thermal reaction of Ru3(CO)12 with ethacrynic acid, 4-[bis(2-chlorethyl)amino]benzenebutanoic acid (chlorambucil), or 4-phenylbutyric acid in refluxing solvents, followed by addition of two-electron donor ligands (L), gives the diruthenium complexes Ru2 (CO)4(O2CR)2L2 (1: R = CH2O-C6H2Cl2-COC(CH2)C2H5, L = C5H5N; 2: R = CH2O-C6H2Cl2-COC(CH2)C2H5, L = PPh3; 3: R = C3H6-C6H4-N(C2H4-Cl)2, L = C5H5N; 4: R = C3H6-C6H4-N(C2H4-Cl)2, L = PPh3; 5: R = C3H6-C6H5, L = C5H5N; 6: R = C3H6-C6H5, L = PPh3). The single-crystal structure analyses of 2, 3, 5 and 6 reveal a dinuclear Ru2(CO)4 sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two L ligands occupy the axial positions of the diruthenium unit.
Mono and dinuclear iridium, rhodium and ruthenium complexes containing chelating carboxylato pyrazine ligands: Synthesis, molecular structure and electrochemistry
The mononuclear complexes [(η5-C5Me5)IrCl(L1)] (1), [(η5-C5Me5)RhCl(L1)] (2), [(η6-p-PriC6H4Me)RuCl(L1)] (3) and [(η6-C6Me6)RuCl(L1)] (4) have been synthesised from pyrazine-2-carboxylic acid (HL1) and the corresponding complexes [{(η5-C5Me5)IrCl2}2], [{(η5-C5Me5)RhCl2}2], [{(η6-p-PriC6H4Me)RuCl2}2], and [{(η6-C6Me6)RuCl2}2], respectively. The related dinuclear complexes [{(η5-C5Me5)IrCl}2 (μ-L2)] (5), [{(η5-C5Me5)RhCl}2 (μ-L2)] (6), [{(η6-p-PriC6H4Me)RuCl}2 (μ-L2)] (7) and [{(η6-C6Me6)RuCl}2 (μ-L2)] (8) have been obtained in a similar manner from pyrazine-2,5-dicarboxylic acid (H2L2). Compounds isomeric to the latter series, [{(η5-C5Me5)IrCl}2 (μ-L3)] (9), [{(η5-C5Me5)RhCl}2 (μ-L3)] (10), [{(p-PriC6H4Me)RuCl}2 (μ-L3)] (11) and [{(η6-C6Me6)RuCl}2 (μ-L3)] (12), have been prepared by using pyrazine-2,3-dicarboxylic acid (H2L3) instead of H2L2. The molecular structures of 2 and 3, determined by X-ray diffraction analysis, show the pyrazine-2-carboxylato moiety to act as an N,O-chelating ligand, while the structure analyses of 5–7, confirm that the pyrazine-2,5-dicarboxylato unit bridges two metal centres. The electrochemical behaviour of selected representatives has been studied by voltammetric techniques.
Mono and dinuclear rhodium, iridium and ruthenium complexes containing chelating 2,2′-bipyrimidine ligands: Synthesis, molecular structure, electrochemistry and catalytic properties
The mononuclear cations [(η5-C5Me5)RhCl(bpym)]+ (1), [(η5-C5Me5)IrCl(bpym)]+ (2), [(η6-p-PriC6H4Me)RuCl(bpym)]+ (3) and [(η6-C6Me6)RuCl(bpym)]+ (4) as well as the dinuclear dications [{(η5-C5Me5)RhCl}2 (bpym)]2+ (5), [{(η5-C5Me5)IrCl}2 (bpym)]2+ (6), [{(η6-p-PriC6H4Me)RuCl}2 (bpym)]2+ (7) and [{(η6-C6Me6)RuCl}2 (bpym)]2+ (8) have been synthesised from 2,2′-bipyrimidine (bpym) and the corresponding chloro complexes [(η5-C5Me5)RhCl2]2, [(η5-C5Me5)IrCl2]2, [(η6-PriC6H4Me)RuCl2]2 and [(η6-C6Me6)RuCl2]2, respectively. The X-ray crystal structure analyses of [3][PF6], [5][PF6]2, [6][CF3SO3]2 and [7][PF6]2 reveal a typical piano-stool geometry around the metal centres; in the dinuclear complexes the chloro ligands attached to the two metal centres are found to be, with respect to each other, cis oriented for 5 and 6 but trans for 7. The electrochemical behaviour of 1–8 has been studied by voltammetric methods. In addition, the catalytic potential of 1–8 for transfer hydrogenation reactions in aqueous solution has been evaluated: All complexes catalyse the reaction of acetophenone with formic acid to give phenylethanol and carbon dioxide. For both the mononuclear and dinuclear series the best results were obtained (50 °C, pH 4) with rhodium complexes, giving turnover frequencies of 10.5 h−1 for 1 and 19 h−1 for 5.
Dinuclear ruthenium sawhorse-type complexes containing bridging ligands with ferrocenyl substituents in endo/endo, endo/exo and exo/exo orientations
The dinuclear ruthenium complexes Ru2(CO)4(OOCC5H4FeC5H5)2L2 (L = NC5H5: 1, L = PPh3: 2) have been synthesized from Ru3(CO)12, ferrocene carboxylic acid and pyridine or triphenylphosphine, respectively. The single-crystal X-ray structure analysis reveals for 1 and 2 a Ru2(CO)4 sawhorse backbone with the two ferrocenyl substituents of the two carboxylato bridges being endo/exo with respect to each other in the solid state. With the new pyridine derivative NC5H4OOCC5H4FeC5H5 (4-ferrocenoyl pyridine) (3) as axial ligand, the complex Ru2(CO)4(OOCC5H4FeC5H5)2(NC5H4OOCC5H4FeC5H5)2 (4) was obtained, the single crystal X-ray structure analysis showing an exo/exo orientation of the two carboxylato bridges in the solid state. The endo/endo orientation is found in the solid-state structure of Ru2(CO)4(HNOCC5H4FeC5H5)2(PPh3)2 (5), the two OCNH bridges being transoïd with respect to each other; this complex is accessible from Ru3(CO)12, ferrocenamide and triphenylphosphine.