2026-04-13T02:21:23Zhttps://recercat.cat/oai/request

oai:recercat.cat:10256/250042024-06-21T12:30:34Zcom_2072_452955com_2072_2054col_2072_453073

00925njm 22002777a 4500 dc Sancho, Ignacio author Navarro, Marta author Montilla Busquets, Marc author Salvador Sedano, Pedro author Santamaría Angulo, Cristina author Luis Luis, Josep Maria author Hernán-Gómez Robledo, Alberto author 2023-08-31 Titanium compounds in low oxidation states are highly reducing species and hence powerful tools for the functionalization of small molecules. However, their potential has not yet been fully realized because harnessing these highly reactive complexes for productive reactivity is generally challenging. Advancing this field, herein we provide a detailed route for the formation of titanium(III) orthophenylendiamido (PDA) species using [LiBHEt3] as a reducing agent. Initially, the corresponding lithium PDA compounds [Li2(ArPDA)(thf)3] (Ar = 2,4,6-trimethylphenyl (MesPDA), 2,6-diisopropylphenyl (iPrPDA)) are combined with [TiCl4(thf)2] to form the heterobimetallic complexes [{TiCl(ArPDA)}(μ-ArPDA){Li(thf)n}] (n = 1, Ar = iPr 3 and n = 2, Ar = Mes 4). Compound 4 evolves to species [Ti(MesPDA)2] (6) via thermal treatment. In contrast, the transformation of 3 into [Ti(iPrPDA)2] (5) only occurs in the presence of [LiNMe2], through a lithium-assisted process, as revealed by density functional theory (DFT). Finally, the Ti(IV) compounds 3–6 react with [LiBHEt3] to give rise to the Ti(III) species [Li(thf)4][Ti(ArPDA)2] (Ar = iPr 8, Mes 9). These low-valent compounds in combination with [PPN]Cl (PPN = bis(triphenylphosphine)iminium) are proved to be highly selective catalysts for the copolymerization of CO2 and cyclohexene epoxide. Reactions occur at 1 bar pressure with activity/selectivity levels similar to Salen–Cr(III) compounds http://hdl.handle.net/10256/25004 Catalitzadors Catalysts Lligands Ligands Copolímers Copolymers Titani Titanium Ti(III) Catalysts for CO2/Epoxide Copolymerization at Unusual Ambient Pressure Conditions