SLIDE 1
Organoruthenium Chemistry
Dongmin Xu Baran Group Meeting 03/02/19
Ruthenium
d8 second-row transition metal Silvery-white, metallic appearance Possible oxidation states: -2 to +8 Toxicity not well studied except RuO4 Density = 12.45 g/cm3, m.p. = 2334 °C (8th in metals) 6th rarest element in Earth’s crust (after Os, Rh, Ir, Re, Pd)
- Named after Ruthenia, a Latin word that refers to Russia
- Ru has 7 natural stable isotopes, along with 34 radioisotopes
- Global production ~12 tons per year; projected world reserve ~5000 tons
- Mostly as byproduct of copper, nickel, or platinum mining
- Current market price: $266/ozt, or $8.55/g
Aldrich price: $112/g (200 mesh powder, 99.9% trace metal basis)
- Percentage of Ru in mined platinum group metal mixture varies greatly
- e.g. 11% in South Africa vs. 2% in certain parts of Russia
- Parker 51 fountain pen has a 14K gold nib tipped with 96.2% Ru and 3.8% Ir
Fun Facts: Important events in the history of Ru:
- 1650s: Platinum alloy (contains Pt, Ru, Os, Rh, Pd, Ir) was discovered
- 1844: Karl Ernst Claus discovered ruthenium by dissolving crude Pt with aqua
regia and examining the residues
- 1953: Djerassi discovered the oxidizing capability of RuO4
- 1965: Allen and Senoff reported an unprecedented [Ru(NH3)5(N2)]X2 complex
- 1987: TPAP was first synthesized by Ley and Griffith
- 1992: Grubbs et al reported the first Ru carbene catalyst for olefin metathesis
- Adding 0.1% Ru to titanium increases
its corrosion resistance by 100 times
- Hardening of Pt and Pd; used in
manufacture of jewelry and electrical contacts
- Ru-Mo superconductors
Applications: d8, second-row, variable ox. states and geometries = versatile reactivity
- Hydrogenation
- Oxidation
- Ruthenacycle mediated reactions
- Addition to Ru π complexes
- Ru vinylidene mediated reactions
- C-H activation
- Metathesis
- Olefin isomerization
- Cyclopropanation
- Radical addition
- Ru-catalyzed click reaction
- Cross coupling
Useful Reviews:
- Murahashi, Chem. Rev. 1998, 2599.
- Trost, Chem. Rev. 2001, 2067.
- Alcaide, Chem. Rev. 2009, 3817.
- Ru-catalyzed olefin metathesis:
Grubbs, Chem. Soc. Rev., 2018, 4510. Hoveyda, JOC, 2014, 4763.
- Photoredox: MacMillan, Chem. Rev.
2013, 5322. NOT covered in this group meeting:
- Reactions using Ru as a Lewis acid
- Photochemistry
Hydrogenation:
Chemoselective hydrogenation with H2: RuCl2(PPh3)3 (cat.) In the appendices:
- Syntheses of common Ru complexes
“Compared to Rh, Ir, and Co, ruthenium complexes generally have less effective catalytic activities for hydrogenation of simple alkenes.” H2 (100 atm), 50 °C 94%
O Me O Me O Me O Me
Tsuneda, Bull. Chem. Soc. Jpn. 1973, 279. RuCl2(CO)(PPh3)3 (cat.) H2 (14 atm), 158 °C 95% [Ru], ZrO2, ZnSO4 (aq) “bilayer catalytic system” H2 (50 atm), 150 °C >60%
- Developed by Asahi
Chemical Co., Japan
- >50000 tons annually