Water-soluble transition metal complexes of ruthenium(ii), osmium(ii), rhodium(iii) and iridium(iii) with chelating N-heterocyclic carbene ligands in hydrogenation and transfer hydrogenation catalysis.

Title Water-soluble transition metal complexes of ruthenium(ii), osmium(ii), rhodium(iii) and iridium(iii) with chelating N-heterocyclic carbene ligands in hydrogenation and transfer hydrogenation catalysis.
Authors E.Bayón Castañón; M. Kaposi; R.M. Reich; F.E. Kühn
Journal Dalton Trans
DOI 10.1039/c7dt04684g
Abstract

The synthesis of novel Ru(ii), Os(ii), Rh(iii) and Ir(iii) mono-N-heterocyclic carbene (NHC) complexes with a pyridine substituent is reported. The reaction of the imidazolium salts bearing N-alkyl and sulfonated N-alkyl substituents with Ag2O leads to the formation of the corresponding Ag(i) complexes. The metal complexes are available in good yields via transmetallation reactions from the corresponding silver complexes and [ArMCl2]2, where Ar = p-cymene or Cp* and M = Ru, Os, Rh or Ir. While N-alkyl substituted NHC complexes are almost insoluble in water (1.55 mg ml-1), sulfonated N-alkyl substituted NHC complexes display good solubility in water (up to 400 mg mL-1). All complexes were examined as catalysts in the transfer hydrogenation of acetophenone, which is quantitatively and highly selective reduced to 1-phenylethanol and 1-cyclohexylethanol. Additionally, the water-soluble complexes were examined in the complete hydrogenation of acetophenone with hydrogen in an autoclave, showing high conversions compared to literature-known systems.

Citation E.Bayón Castañón; M. Kaposi; R.M. Reich; F.E. Kühn.Water-soluble transition metal complexes of ruthenium(ii), osmium(ii), rhodium(iii) and iridium(iii) with chelating N-heterocyclic carbene ligands in hydrogenation and transfer hydrogenation catalysis.. Dalton Trans. 2018;47(7):23182329. doi:10.1039/c7dt04684g

Related Elements

Iridium

See more Iridium products. Iridium (atomic symbol: Ir, atomic number: 77) is a Block D, Group 9, Period 6 element with an atomic weight of 192.217. The number of electrons in each of iridium's shells is [2, 8, 18, 32, 15, 2] and its electron configuration is [Xe] 4f14 5d7 6s2. Iridium Bohr ModelThe iridium atom has a radius of 136 pm and a Van der Waals radius of 202 pm. Iridium was discovered and first isolated by Smithson Tennant in 1803. In its elemental form, Iridium has a silvery white appearance. Iridium is a member of the platinum group of metals.Elemental Iridium It is the most corrosion resistant metal known and is the second-densest element (after osmium). It will not react with any acid and can only be attacked by certain molten salts, such as molten sodium chloride. Iridium is found as an uncombined element and in iridium-osmium alloys. Iridium's name is derived from the Greek goddess Iris, personification of the rainbow, on account of the striking and diverse colors of its salts.

Osmium

See more Osmium products. Osmium (atomic symbol: Os, atomic number: 76) is a Block D, Group 8, Period 6 element with an atomic weight of 190.23. Osmium Bohr ModelThe number of electrons in each of osmium's shells is [2, 8, 18, 32, 14, 2] and its electron configuration is [Xe] 4f14 5d6 6s2. The osmium atom has a radius of 135 pm and a Van der Waals radius of 216 pm. Osmium was discovered and first isolated by Smithson Tennant in 1803. Elemental OsmiumIn its elemental form, osmium has a silvery blue cast apperance. Osmium has the highest melting point and the lowest vapor pressure of any of the platinum group of metals it is also the densest naturally ocurring element. Osmium is the least abundant stable element in the earth's crust. It is found in the alloys osmiridium and iridiosmium and as a free element. The origin of the name Osmium comes from the Greek word osme, meaning a smell or odor.

Rhodium

See more Rhodium products. Rhodium (atomic symbol: Rh, atomic number: 45) is a Block D, Group 9, Period 5 element with an atomic weight of 102.90550. Rhodium Bohr ModelThe number of electrons in each of Rhodium's shells is [2, 8, 18, 16, 1] and its electron configuration is [Kr] 4d8 5s1. The rhodium atom has a radius of 134 pm and a Van der Waals radius of 195 pm. Rhodium was discovered and first isolated by William Wollaston in 1804. In its elemental form, rhodium has a silvery white metallic appearance. Elemental RhodiumRhodium is a member of the platinum group of metals. It has a higher melting point than platinum, but a lower density. Rhodium is found in ores mixed with other metals such as palladium, silver, platinum, and gold. Rhodium is primarily used as the catalyst in the three-way catalytic converters of automobiles it is also highly valued in jewelry. The name Rhodium originates from the Greek word 'Rhodon,' which means rose.

Ruthenium

See more Ruthenium products. Ruthenium (atomic symbol: Ru, atomic number: 44) is a Block D, Group 8, Period 5 element with an atomic weight of 101.07. Ruthenium Bohr ModelThe number of electrons in each of ruthenium's shells is [2, 8, 18, 15, 1] and its electron configuration is [Kr] 4d7 5s1. The ruthenium atom has a radius of 134 pm and a Van der Waals radius of 207 pm. Ruthenium was discovered by Jędrzej Śniadecki in 1807. It was first recognized as a distinct element by Karl Ernst Claus in 1844. Elemental RutheniumIn its elemental form, ruthenium has a silvery white metallic appearance. Ruthenium is a rare transition metal belonging to the platinum group of metals. It is found in pentlandite, pyroxenite, and platinum group metal ores. The name Ruthenium originates from the Latin word "Ruthenia," meaning Russia.

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