Z-Selective Semihydrogenation of Internal Alkynes Catalyzed by Phenanthroline-Based PNNP-Fe(II) Complexes Tao Wang, Yoshihito Kayaki, Hiroto Fujisaki, Hajime Kawanami, Yoshihiro Shimoyama, et al. Chemcatchem, 2025 Fe(II) complexes bearing a phenanthroline‐based tetradentate PNNP ligand (2,9‐bis[(diphenylphosphino)methyl]‐1,10‐phenanthroline, 2,9‐bis[(dicyclohexylphosphino)methyl]‐1,10‐phenanthroline) were applied as metal–ligand cooperative catalysts to promote semihydrogenation of internal alkynes. The reaction proceeded with atmospheric H2 at a catalyst loading of 2–5 mol%/Fe to selectively produce the corresponding Z‐alkenes. The reactions exhibited good functional group compatibility toward substrates with various substituents, including polar ester and cyano groups, as well as a coordinating sulfur‐containing thiophene moiety.
One-Step Esterification of Phosphoric, Phosphonic and Phosphinic Acids with Organosilicates: Phosphorus Chemical Recycling of Sewage Waste Yuki Naganawa, Kei Sakamoto, Akira Fujita, Kazuya Morimoto, Manussada Ratanasak, et al. Angewandte Chemie International Edition, 2025 Global concerns regarding the depletion and strategic importance of phosphorus resources have increased demand for the recovery and recycling. However, waste‐derived phosphorus compounds, primarily as chemically inert phosphoric acid or its salts, present a challenge to their direct conversion into high‐value chemicals. We aimed to develop an innovative technology that utilizes the large quantities of sewage waste, bypasses the use of white phosphorus, and enables esterification of phosphoric acid to produce widely applicable phosphate triesters. Tetraalkyl orthosilicates emerged as highly effective reagents for the direct triple esterification of 85 % phosphoric acid, as well as the esterification of organophosphinic and phosphonic acids. Furthermore, we achieved esterification of recovered phosphoric acid with tetraalkyl orthosilicate, thus pioneering a recycling pathway from sewage waste to valuable phosphorus chemicals. Experimental and theoretical investigations revealed a novel mechanism, wherein tetraalkyl orthosilicates facilitate multimolecular aggregation to achieve alkyl transfer from tetraalkylorthosilicate to phosphoric acid via multiple proton shuttling.
Catalytic thiolation-depolymerization-like decomposition of oxyphenylene-type super engineering plastics via selective carbon–oxygen main chain cleavages Yasunori Minami, Sae Imamura, Nao Matsuyama, Yumiko Nakajima, Masaru Yoshida Communications Chemistry, 2024 As the effective use of carbon resources has become a pressing societal issue, the importance of chemical recycling of plastics has increased. The catalytic chemical decomposition for plastics is a promising approach for creating valuable products under efficient and mild conditions. Although several commodity and engineering plastics have been applied, the decompositions of stable resins composed of strong main chains such as polyamides, thermoset resins, and super engineering plastics are underdeveloped. Especially, super engineering plastics that have high heat resistance, chemical resistance, and low solubility are nearly unexplored. In addition, many super engineering plastics are composed of robust aromatic ethers, which are difficult to cleave. Herein, we report the catalytic depolymerization-like chemical decomposition of oxyphenylene-based super engineering plastics such as polyetheretherketone and polysulfone using thiols via selective carbon–oxygen main chain cleavage to form electron-deficient arenes with sulfur functional groups and bisphenols. The catalyst combination of a bulky phosphazene base P4-tBu with inorganic bases such as tripotassium phosphate enabled smooth decomposition. This method could be utilized with carbon- or glass fiber-enforced polyetheretherketone materials and a consumer resin. The sulfur functional groups in one product could be transformed to amino and sulfonium groups and fluorine by using suitable catalysts.
