Chelating dioxygen compounds of the platinum metals

Choy, V. J.; O’Connor, Charmian J.

doi:10.1016/s0010-8545(00)80226-x

Cited by 80 publications

(17 citation statements)

References 65 publications

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“…Particularly intriguing is the detection of an ion with molecular formula as C 4 H 12 N 2 O 5 Ru 1 , which can be assigned as [Ru III + T + NH 3 + O 2 − 2H] + . Dioxygen interaction with a variety of Ru complexes had been previously documented; however, the oxo‐ and dioxo‐ruthenium complexes are typically associated with high‐oxidation states of the metal (IV and higher) . Although the discussion of the possible structures of oxo/dioxo‐complexes of ruthenium falls outside of the scope of this manuscript, we note that Ru/O 2 association is likely to be related to the metal oxidation process, and the corresponding complexes may represent either intermediate steps or by‐products of the Ru II → Ru III transition.…”

Section: Resultsmentioning

confidence: 99%

Ruthenium coordination preferences in imidazole‐containing systems revealed by electrospray ionization mass spectrometry and molecular modeling: Possible cues for the surprising stability of the Ru (III)/tris (hydroxymethyl)‐aminomethane/imidazole complexes

et al. 2019

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Ruthenium is a platinoid that exhibits a range of unique chemical properties in solution, which are exploited in a variety of applications, including luminescent probes, anticancer therapies, and artificial photosynthesis. This paper focuses on a recently demonstrated ability of this metal in its +3 oxidation state to form highly stable complexes with tris (hydroxymethyl)aminomethane (H2NC(CH2OH)3, Tris‐base or T) and imidazole (Im) ligands, where a single RuIII cation is coordinated by two molecules of each T and Im. High‐resolution electrospray ionization mass spectrometry (ESI MS) is used to characterize RuIII complexes formed by placing a RuII complex [(NH3)5RuIICl]Cl in a Tris buffer under aerobic conditions. The most abundant ionic species in ESI MS represent mononuclear complexes containing an oxidized form of the metal, ie, [XnRuIIIT2 – 2H]+, where X could be an additional T (n = 1) or NH3 (n = 0‐2). Di‐ and tri‐metal complexes also give rise to a series of abundant ions, with the highest mass ion representing a metal complex with an empirical formula Ru3C24O21N6H66 (interpreted as cyclo(T2RuO)3, a cyclic oxo‐bridged structure, where the coordination sphere of each metal is completed by two T ligands). The empirical formulae of the binuclear species are consistent with the structures representing acyclic fragments of cyclo(T2RuO)3 with addition of various combinations of ammonia and dioxygen as ligands. Addition of histidine in large molar excess to this solution results in complete disassembly of poly‐nuclear complexes and gives rise to a variety of ionic species in the ESI mass spectrum with a general formula [RuIIIHiskTm (NH3)n − 2H]+, where k = 0 to 2, m = 0 to 3, and n = 0 to 4. Ammonia adducts are present for all observed combinations of k and m, except k = m = 2, suggesting that [His2RuIIIT2 − 2H]+ represents a complex with a fully completed coordination sphere. The observed cornucopia of RuIII complexes formed in the presence of histidine is in stark contrast to the previously reported selective reactivity of imidazole, which interacts with the metal by preserving the RuT2 core and giving rise to a single abundant ruthenium complex (represented by [Im2RuIIIT2 − 2H]+ in ESI mass spectra). Surprisingly, the behavior of a hexa‐histidine peptide (HHHHHH) is similar to that of a single imidazole, rather than a single histidine amino acid: The RuT2 core is preserved, with the following ionic species observed in ESI mass spectra: [HHHHHH·(RuIIIT2)m − (3m‐1)H]+ (m = 1‐3). The remarkable selectivity of the imidazole interaction with the RuIIIT2 core is rationalized using energetic considerations at the quantum mechanical level of theory.

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Section: Resultsmentioning

confidence: 99%

Ruthenium coordination preferences in imidazole‐containing systems revealed by electrospray ionization mass spectrometry and molecular modeling: Possible cues for the surprising stability of the Ru (III)/tris (hydroxymethyl)‐aminomethane/imidazole complexes

et al. 2019

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“…The behavior of the low valent vanadium complex, [C5H5V(CO)4], is quite different from that of the vanadium ( IV ) complexes : [VO ( acac ) 2] and [(05Ηδ)2ν012]. Neither vanadylacetylacetonate nor bis ( cyclopentadienyl ) dichlorovanadium ( IV ) could rapidly initiate TME oxidation at 50°C.…”

Section: Resultsmentioning

confidence: 99%

Oxidation of Olefins in the Presence of Transition Metal Complexes

Lyons

1974

Advances in Chemistry

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With certain metal complexes the product profile resulting from olefin oxidation differs greatly from that of classical autoxidation. Reactions carried out in the presence of cer tain metal complexes are highly selective in forming one product or a single set of products. When group VIII metal complexes are used, α,β unsaturated alcohols and ketones predominate. With molybdenum, epoxides are formed in high yield; with vanadium complexes, epoxy alcohols are formed. The oxidation of substituted olefins by the com plexes which we studied proceeds via an allylic hydroper oxide intermediate. The observed products are a function of the selective decomposition of the allylic hydroperoxide by the metal complex. In the decomposition of allylic hydroperoxides the products obtained with a given complex parallel the results of oxidation. Manytransition metal complexes react reversibly with molecular oxygen (1, 2) and with olefins (3, 4, 5). van Gaal et al. (6) recently prepared a group VIII metal complex which contains both oxygen and an olefin in the coordination sphere (Reaction 1).(1) L = PPh; PPh3 64

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“…The remaining PhBr in Et 2 O (5 cm 3 ) was added dropwise and the mixture was refluxed for 40 min. To this mixture, 1.03 cm 3 (0.01 mol) of PhBr in anhydrous Et 2 O (5 cm 3 ) and the Ru(III) Schiff base complex (0.05 mmol) chosen for investigation were added and heated under reflux for 6 h. The reaction mixture was cooled and hydrolyzed with a saturated solution of aqueous NH 4 Cl and the ether extract on evaporation gave a crude product which was chromatographed using petroleum ether as a solvent to get pure biphenyl and compared well with an authentic sample. The blank reaction was carried out and the product obtained was in a lesser amount when compared with the reaction in the presence of the catalyst.…”

Section: Aryl-aryl Coupling Reaction By Ruthenium(iii) Schiff Base Comentioning

confidence: 99%

“…The study of complexes capable of reversible binding of molecular oxygen, known as oxygen carriers, has received a great deal of interest. [4,5] In general chelating ligands, which are good σ -donors, increase the electron density on the metal atom, facilitating dioxygen binding. In addition, some complexes containing nitrogen and oxygen donor atoms in the complexes are effective as stereospecific catalysts for oxidation, [6] reduction, [7] hydrolysis, [8] biocidal activity [9] and other transformations of organic and inorganic chemistry.…”

Section: Introductionmentioning

confidence: 99%