Imidazole Based Ruthenium(IV) Complexes as Highly Efficient Bifunctional Catalysts for the Redox Isomerization of Allylic Alcohols in Aqueous Medium: Water as Cooperating Ligand

Bis-allyl ruthenium­(IV) complexes containing 1,3 azole β-N-H protic ligands [Ru­(η³:η³-C₁₀H₁₆)­Cl₂L] (C₁₀H₁₆ = 2,7-dimethylocta-2,6-diene-1,8-diyl) (L = imidazole (<b>1a</b>), benzimidazole (<b>1b</b>)), and <i>N</i>-methylimidazole (<b>1c</b>) are highly active precatalysts in the redox isomerization of allylic alcohols into carbonyl compounds in aqueous medium and in the absence of base. A wide series of primary and secondary allylic alcohols can be isomerized into the corresponding carbonyl compounds. Remarkably, complex <b>1b</b> has been found to be the most efficient catalyst reported to date for the isomerization of 1-octen-3-ol in water leading to a turnover frequency (TOF) value of 60 000 h^–1. Moreover, catalyst <b>1b</b> can be recycled remaining active up to seven cycles. Density functional theory (DFT) calculations give evidence that the hydroxo complexes derived from <b>1a</b>–<b>c</b> species can be formed in aqueous solution and that they can act as the catalytic active species in a bifunctional catalyzed process. This study demonstrate that in water the participation of the β-N-H protic group of the 1,3-azole ligands in the bifunctional catalysis is not required, provided that a water molecule can act as cooperating ligand

Imidazole Based Ruthenium(IV) Complexes as Highly Efficient Bifunctional Catalysts for the Redox Isomerization of Allylic Alcohols in Aqueous Medium: Water as Cooperating Ligand

Bis-allyl ruthenium­(IV) complexes containing 1,3 azole β-N-H protic ligands [Ru­(η³:η³-C₁₀H₁₆)­Cl₂L] (C₁₀H₁₆ = 2,7-dimethylocta-2,6-diene-1,8-diyl) (L = imidazole (<b>1a</b>), benzimidazole (<b>1b</b>)), and <i>N</i>-methylimidazole (<b>1c</b>) are highly active precatalysts in the redox isomerization of allylic alcohols into carbonyl compounds in aqueous medium and in the absence of base. A wide series of primary and secondary allylic alcohols can be isomerized into the corresponding carbonyl compounds. Remarkably, complex <b>1b</b> has been found to be the most efficient catalyst reported to date for the isomerization of 1-octen-3-ol in water leading to a turnover frequency (TOF) value of 60 000 h^–1. Moreover, catalyst <b>1b</b> can be recycled remaining active up to seven cycles. Density functional theory (DFT) calculations give evidence that the hydroxo complexes derived from <b>1a</b>–<b>c</b> species can be formed in aqueous solution and that they can act as the catalytic active species in a bifunctional catalyzed process. This study demonstrate that in water the participation of the β-N-H protic group of the 1,3-azole ligands in the bifunctional catalysis is not required, provided that a water molecule can act as cooperating ligand

Imidazole Based Ruthenium(IV) Complexes as Highly Efficient Bifunctional Catalysts for the Redox Isomerization of Allylic Alcohols in Aqueous Medium: Water as Cooperating Ligand

Bis-allyl ruthenium­(IV) complexes containing 1,3 azole β-N-H protic ligands [Ru­(η³:η³-C₁₀H₁₆)­Cl₂L] (C₁₀H₁₆ = 2,7-dimethylocta-2,6-diene-1,8-diyl) (L = imidazole (<b>1a</b>), benzimidazole (<b>1b</b>)), and <i>N</i>-methylimidazole (<b>1c</b>) are highly active precatalysts in the redox isomerization of allylic alcohols into carbonyl compounds in aqueous medium and in the absence of base. A wide series of primary and secondary allylic alcohols can be isomerized into the corresponding carbonyl compounds. Remarkably, complex <b>1b</b> has been found to be the most efficient catalyst reported to date for the isomerization of 1-octen-3-ol in water leading to a turnover frequency (TOF) value of 60 000 h^–1. Moreover, catalyst <b>1b</b> can be recycled remaining active up to seven cycles. Density functional theory (DFT) calculations give evidence that the hydroxo complexes derived from <b>1a</b>–<b>c</b> species can be formed in aqueous solution and that they can act as the catalytic active species in a bifunctional catalyzed process. This study demonstrate that in water the participation of the β-N-H protic group of the 1,3-azole ligands in the bifunctional catalysis is not required, provided that a water molecule can act as cooperating ligand

Imidazole Based Ruthenium(IV) Complexes as Highly Efficient Bifunctional Catalysts for the Redox Isomerization of Allylic Alcohols in Aqueous Medium: Water as Cooperating Ligand

Bis-allyl ruthenium­(IV) complexes containing 1,3 azole β-N-H protic ligands [Ru­(η³:η³-C₁₀H₁₆)­Cl₂L] (C₁₀H₁₆ = 2,7-dimethylocta-2,6-diene-1,8-diyl) (L = imidazole (<b>1a</b>), benzimidazole (<b>1b</b>)), and <i>N</i>-methylimidazole (<b>1c</b>) are highly active precatalysts in the redox isomerization of allylic alcohols into carbonyl compounds in aqueous medium and in the absence of base. A wide series of primary and secondary allylic alcohols can be isomerized into the corresponding carbonyl compounds. Remarkably, complex <b>1b</b> has been found to be the most efficient catalyst reported to date for the isomerization of 1-octen-3-ol in water leading to a turnover frequency (TOF) value of 60 000 h^–1. Moreover, catalyst <b>1b</b> can be recycled remaining active up to seven cycles. Density functional theory (DFT) calculations give evidence that the hydroxo complexes derived from <b>1a</b>–<b>c</b> species can be formed in aqueous solution and that they can act as the catalytic active species in a bifunctional catalyzed process. This study demonstrate that in water the participation of the β-N-H protic group of the 1,3-azole ligands in the bifunctional catalysis is not required, provided that a water molecule can act as cooperating ligand

Series of 2D Heterometallic Coordination Polymers Based on Ruthenium(III) Oxalate Building Units: Synthesis, Structure, and Catalytic and Magnetic Properties

A series of 2D ruthenium-based coordination polymers with hcb-hexagonal topology, {[K­(18-crown-6)]₃[M^II₃(H₂O)₄{Ru­(ox)₃}₃]}<i>_n</i> (M^II = Mn (<b>1</b>), Fe (<b>2</b>), Co (<b>3</b>), Cu (<b>4</b>), Zn (<b>5</b>)), has been synthesized through self-assembly reaction. All compounds are isostructural frameworks that crystallize in the monoclinic space group <i>C</i>2/<i>c</i>. The crystal packing consists of a 2D honeycomb-like anionic mixed-metal framework intercalated by [K­(18-crown-6)]⁺ cationic template. Dehydration processes take place in the range 40–200 °C exhibiting two phase transitions. However, the spontaneous rehydration occurs at room temperature. Both hydrated and dehydrated compounds were tested as Lewis acids heterogeneous catalysts in the acetalyzation of benzaldehyde achieving high yields with the possibility to be recovered and reused. All the investigated materials do not show any long-range magnetic ordering down to 2 K. However, the Fe-based compound <b>2</b> presents a magnetic irreversibility in the ZFC-FC magnetization data below 5 K, which suggest a spin-glass-like behavior, characterized also by short-range ferromagnetic correlations. The coercive field increases as the temperature is lowered below 5 K, reaching a value of 1 kOe at 2 K. Alternating current measurements obtained at different frequencies confirm the freezing process that shows weak frequency dependence, being characteristic of a system exhibiting competing magnetic interactions

Synthesis and Reactivity of New Rhenium(I) Complexes Containing Iminophosphorane-Phosphine Ligands: Application to the Catalytic Isomerization of Propargylic Alcohols in Ionic Liquids

[ReBr­(CO)₅] reacts with the iminophosphorane–phosphine ligands Ph₂PCH₂P­(NR)­Ph₂ (R = P­(O)­(OEt)₂ (<b>1a</b>), P­(O)­(OPh)₂ (<b>1b</b>), P­(S)­(OEt)₂ (<b>1c</b>), P­(S)­(OPh)₂ (<b>1d</b>), 4-C₆F₄CHO (<b>1e</b>), 4-C₆F₄CN (<b>1f</b>), 4-C₅F₄N (<b>1g</b>)) affording the neutral complexes [ReBr­(κ²-<i>P</i>,<i>X</i>-Ph₂PCH₂P­{NP­(X)­(OR)₂}­Ph₂)­(CO)₃] (X = O, R = Et (<b>2a</b>), Ph (<b>2b</b>); X = S, R = Et (<b>2c</b>), Ph (<b>2d</b>)) and [ReBr­{κ²-<i>P</i>,<i>N</i>-Ph₂PCH₂P­(NR)­Ph₂}­(CO)₃] (R = P­(O)­(OEt)₂ (<b>3a</b>), P­(O)­(OPh)₂ (<b>3b</b>), 4-C₆F₄CHO (<b>3e</b>), 4-C₆F₄CN (<b>3f</b>), 4-C₅F₄N (<b>3g</b>)). The reactivity of the cationic complex [Re­(κ³-<i>P</i>,<i>N</i>,<i>S</i>-Ph₂PCH₂P­{NP­(S)­(OPh)₂}­Ph₂)­(CO)₃]­[SbF₆] (<b>4d</b>) has been explored allowing the synthesis of the cationic [Re­(L)­(κ²-<i>P</i>,<i>S</i>-Ph₂PCH₂P­{NP­(S)­(OPh)₂}­Ph₂)­(CO)₃]­[SbF₆] (L = acetone (<b>5a</b>), CH₃CN (<b>5b</b>), pyridine (<b>5c</b>), PPh₃ (<b>5d</b>)) and the neutral [ReY­(κ²-<i>P</i>,<i>S</i>-Ph₂PCH₂P­{NP­(S)­(OPh)₂}­Ph₂)­(CO)₃] (Y = Cl (<b>6a</b>), I (<b>6b</b>), N₃ (<b>6c</b>)) complexes. The catalytic activity of complex <b>4d</b> in the regioselective isomerization of terminal propargylic alcohols HCCCR¹R²(OH) into α,β-unsaturated aldehydes R¹R²CCHCHO or ketones R³R⁴CCR¹COMe (if R² = CHR³R⁴) under neutral conditions in ionic liquids has being studied. Isolation and X-ray characterization of the key intermediate rhenium­(I) oxocyclocarbene complex [Re­{C­(CH₂)₃O}­(κ²-<i>P</i>,<i>S</i>-Ph₂PCH₂P­{NP­(S)­(OPh)₂}­Ph₂)­(CO)₃]­[SbF₆] (<b>5e</b>) seems to indicate that the catalytic reaction proceeds through tautomerization of the terminal alkynols to yield vinilydene-type species

Selective Hydration of Nitriles to Amides Promoted by an Os–NHC Catalyst: Formation and X‑ray Characterization of κ²‑Amidate Intermediates

The complex [Os­(η⁶-<i>p</i>-cymene)­(OH)­IPr]­OTf (<b>1</b>; IPr = 1,3-bis­(2,6-diisopropylphenyl)­imidazolylidene; OTf = CF₃SO₃) reacts with benzonitrile and acetonitrile to afford the κ²-amidate derivatives [Os­(η⁶-<i>p</i>-cymene)­{κ²<i>O</i>,<i>N</i>-NHC­(O)­R}­IPr]­OTf (R = Ph (<b>2</b>), CH₃ (<b>3</b>)). Their formation has been investigated by DFT calculations (B3PWP1), starting from the model intermediate [Os­(η⁶-benzene)­(OH)­(CH₃CN)­IMe]⁺ (IMe = 1,3-bis­(2,6-dimethylphenyl)­imidazolylidene). Complex <b>2</b> has been characterized by X-ray diffraction analysis. In the presence of water, the κ²-amidate species release the corresponding amides and regenerate <b>1</b>. In agreement with this, complex <b>1</b> has been found to be an efficient catalyst for the selective hydration of a wide range of aromatic and aliphatic nitriles to amides, including substituted benzonitriles, cyanopyridines, acetonitrile, and 2-(4-isobutylphenyl)­propionitrile among others. The mechanism of the catalysis is also discussed

Selective Hydration of Nitriles to Amides Promoted by an Os–NHC Catalyst: Formation and X‑ray Characterization of κ²‑Amidate Intermediates

The complex [Os­(η⁶-<i>p</i>-cymene)­(OH)­IPr]­OTf (<b>1</b>; IPr = 1,3-bis­(2,6-diisopropylphenyl)­imidazolylidene; OTf = CF₃SO₃) reacts with benzonitrile and acetonitrile to afford the κ²-amidate derivatives [Os­(η⁶-<i>p</i>-cymene)­{κ²<i>O</i>,<i>N</i>-NHC­(O)­R}­IPr]­OTf (R = Ph (<b>2</b>), CH₃ (<b>3</b>)). Their formation has been investigated by DFT calculations (B3PWP1), starting from the model intermediate [Os­(η⁶-benzene)­(OH)­(CH₃CN)­IMe]⁺ (IMe = 1,3-bis­(2,6-dimethylphenyl)­imidazolylidene). Complex <b>2</b> has been characterized by X-ray diffraction analysis. In the presence of water, the κ²-amidate species release the corresponding amides and regenerate <b>1</b>. In agreement with this, complex <b>1</b> has been found to be an efficient catalyst for the selective hydration of a wide range of aromatic and aliphatic nitriles to amides, including substituted benzonitriles, cyanopyridines, acetonitrile, and 2-(4-isobutylphenyl)­propionitrile among others. The mechanism of the catalysis is also discussed