New Wind in Old Sails: Novel Applications of Triphos-based Transition Metal Complexes as Homogeneous Catalysts for Small Molecules and Renewables Activation

Recent developments in the coordination chemistry and applications of Ru-triphos [triphos = 1,1,1-tris-(diphenylphosphinomethyl)ethane] systems are reviewed, highlighting their role as active and selective homogenous catalysts for small molecule activation, biomass conversions and in carbon dioxide utilization-related processes

Microwave-Assisted Pyrolysis Process: From a Laboratory Scale to an Industrial Plant

One of the great challenges for the European Union (EU) is the “Circular Economy Package,” and to achieve this goal, materials at the end of their life cycle must be recycled using a sustainable process. In this way, as a thermochemical treatment, pyrolysis represents a significant opportunity so long it leads to the recovery of both energy and chemical content of mixed, contaminated, or deteriorated plastics. An excellent history of an academic-industrial adventure started in 2008 at the Department of Chemistry of the University of Florence demonstrates the possibility of employing microwaves to recycle plastics to preserve their energy and chemical content. After that, Techwave started industrialization of the process in 2019, realizing a small-scale prototype followed by a full-scale pilot plant using different plastic materials (e.g., polystyrene, acrylonitrile-butadiene-styrene (ABS), and polypropylene). Nowadays, the plant may process 90 kg/h of plastics with a low formation of char and gas and an interesting amount of liquid useful as a source of chemicals or fuel because it has an LHV of 35–43 kJ/kg. The Microwave-Assisted Pyrolysis (MAP) is an industrial novelty in plastic recycling, and it looks very promising for a much more modern and innovative plastic waste recovery system

Iron(II) Complexes of the Linear <i>rac-</i>Tetraphos‑1 Ligand as Efficient Homogeneous Catalysts for Sodium Bicarbonate Hydrogenation and Formic Acid Dehydrogenation

The linear tetraphosphine 1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane (tetraphos-1, P4) was used as its <i>rac</i> and <i>meso</i> isomers for the synthesis of both molecularly defined and in situ formed Fe­(II) complexes. These were used as precatalysts for sodium bicarbonate hydrogenation to formate and formic acid dehydrogenation to hydrogen and carbon dioxide with moderate to good activities in comparison to those for literature systems based on Fe. Mechanistic details of the reaction pathways were obtained by NMR and HPNMR experiments, highlighting the role of the Fe­(II) monohydrido complex [FeH­(<i>rac</i>-P4)]⁺ as a key intermediate. X-ray crystal structures of different complexes bearing <i>rac</i>-P4 were also obtained and are described herein

Selective Formic Acid Dehydrogenation Catalyzed by Fe-PNP Pincer Complexes Based on the 2,6-Diaminopyridine Scaffold

Fe­(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were studied as homogeneous, non-precious-metal-based catalysts for selective formic acid dehydrogenation to hydrogen and carbon dioxide, reaching quantitative yields and high TONs under mild reaction conditions

Selective Formic Acid Dehydrogenation Catalyzed by Fe-PNP Pincer Complexes Based on the 2,6-Diaminopyridine Scaffold

Fe­(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were studied as homogeneous, non-precious-metal-based catalysts for selective formic acid dehydrogenation to hydrogen and carbon dioxide, reaching quantitative yields and high TONs under mild reaction conditions

Selective Formic Acid Dehydrogenation Catalyzed by Fe-PNP Pincer Complexes Based on the 2,6-Diaminopyridine Scaffold

Fe­(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were studied as homogeneous, non-precious-metal-based catalysts for selective formic acid dehydrogenation to hydrogen and carbon dioxide, reaching quantitative yields and high TONs under mild reaction conditions

Inner- versus Outer-Sphere Ru-Catalyzed Formic Acid Dehydrogenation: A Computational Study

A detailed hybrid density functional theory study was carried out to clarify the mechanism of Ru-catalyzed dehydrogenation of formic acid in the presence of the octahedral complexes [Ru­(κ⁴-NP₃)­Cl₂] (<b>1</b>) and [Ru­(κ³-triphos)­(MeCN)₃]­(PF₆)₂ (<b>2·PF</b>_<b>6</b>) [NP₃ = N­(CH₂CH₂­PPh₂)₃, triphos = MeC­(CH₂­PPh₂)₃]. It was shown that Ru-hydrido vs Ru-formato species are pivotal to bringing about the efficient release of H₂ and CO₂ following either a metal-centered (inner-sphere) or a ligand-centered (outer-sphere) pathway, respectively

Inner- versus Outer-Sphere Ru-Catalyzed Formic Acid Dehydrogenation: A Computational Study

A detailed hybrid density functional theory study was carried out to clarify the mechanism of Ru-catalyzed dehydrogenation of formic acid in the presence of the octahedral complexes [Ru­(κ⁴-NP₃)­Cl₂] (<b>1</b>) and [Ru­(κ³-triphos)­(MeCN)₃]­(PF₆)₂ (<b>2·PF</b>_<b>6</b>) [NP₃ = N­(CH₂CH₂­PPh₂)₃, triphos = MeC­(CH₂­PPh₂)₃]. It was shown that Ru-hydrido vs Ru-formato species are pivotal to bringing about the efficient release of H₂ and CO₂ following either a metal-centered (inner-sphere) or a ligand-centered (outer-sphere) pathway, respectively

Inner- versus Outer-Sphere Ru-Catalyzed Formic Acid Dehydrogenation: A Computational Study

A detailed hybrid density functional theory study was carried out to clarify the mechanism of Ru-catalyzed dehydrogenation of formic acid in the presence of the octahedral complexes [Ru­(κ⁴-NP₃)­Cl₂] (<b>1</b>) and [Ru­(κ³-triphos)­(MeCN)₃]­(PF₆)₂ (<b>2·PF</b>_<b>6</b>) [NP₃ = N­(CH₂CH₂­PPh₂)₃, triphos = MeC­(CH₂­PPh₂)₃]. It was shown that Ru-hydrido vs Ru-formato species are pivotal to bringing about the efficient release of H₂ and CO₂ following either a metal-centered (inner-sphere) or a ligand-centered (outer-sphere) pathway, respectively