A Versatile Ruthenium Precursor for Biphasic Catalysis and Its Application in Ionic Liquid Biphasic Transfer Hydrogenation: Conventional vs Task-Specific Catalysts

The synthesis of a novel imidazolium-tagged ruthenium complex, which represents a versatile precursor for aqueous and ionic liquid biphasic catalysis, is reported. Its utility is demonstrated in the highly enantioselective ionic liquid biphasic transfer hydrogenation of acetophenone and is compared to conventional (untagged) complexes

Chemistry of Ruthenium(II) Alkyl Binap Complexes: Novel Bonding, Cyclometalation, and P−C Bond Splitting

Reactions of the bis-isopropyl and bis-cyclohexyl alkyl Binap ligands, 8 and 9, respectively, with [RuCl2(η6-p-cymene)]2 afford new dinuclear chloro-bridged Ru compounds which contain the Binap ligands as six- rather than four-electron donors. A backbone double bond proximate to one of the P-donors complexes the metal atom. NMR details of the olefin bonding plus isomerization reactions involving loss of the olefin complexation are reported. Reactions of 8 or 9 with [Ru(OAc)2(η6-p-cymene)] result in slow P−C bond cleavage and cyclometalation, instead of affording the anticipated [Ru(OAc)2(Binap)] complex. The new cyclometalated complexes, 15 and 16, contain the complexed R2P−O(CO)CH3 ligand and arise (presumably) via acetate attack at phosphorus with the electrons in the P−C bond moving to the ruthenium atom. The solid-state structure of one of these, the cyclohexyl analogue, 16, is reported and represents a rare structural example of a molecule with three different chelate ligands. The complexed R2P−O(CO)CH3 ligand is readily hydrolyzed in wet triflic acid to afford the R2P(OH) donor and an η6-arene ligand (via Ru−C protonation)

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported

Phosphino−Arene Ruthenium Complexes Containing the Phosphorus Acid Anion {P(O)(OR)₂} as P-Donor

The cationic complex [Ru(OTf)(P(OH)Ph2){Ph2P-(η6-arene)}]OTf, 2 (2a = 6‘-diphenylphosphino-1‘-naphthyl-η6(1-6)-naphthalene, 2b = 6,6‘-dimethoxy-2‘-diphenylphosphino-η6(1-6)-biphenyl), is shown to react with water/tert-butyl alcohol/THF mixtures to afford [Ru(P(O)(OH)2{Ph2P-(η6-arene)}]2(OTf)2, 4. The solid-state structure of a derivative, [Ru{P(O)(OH)(OMe)}{Ph2P-(naphthyl-η6-naphthalene}]2(OTf)2, 6, is reported and found to possess extremely asymmetric η6-arene bonding. Complexes 4 and 6, plus a mononuclear dimethoxy analogue, Ru(P(O)(OMe)2(Ph2P-(naphthyl-η6-naphthalene)](OTf), 8, represent the first examples of Ru-compounds that contain the phosphorus acid anion P(O)(OR)2 (R = H and/or Me) as an anionic P-donor ligand. PGSE diffusion measurements are shown to be helpful in distinguishing between dinuclear oxygen bridging species and their mononuclear analogues

Metal−Organic Frameworks Derived from Imidazolium Dicarboxylates and Group I and II Salts

A series of coordination polymers containing Group I or II metal ions, connected via an imidazolium-centered dicarboxylate ligand, have been isolated from water and characterized by single crystal X-ray diffraction. All the structures incorporate water molecules that adopt a range of different structural motifs

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = ethyl, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-soluble monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liquid and in the aqueous reduction of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported