A Robust C₃-Symmetric Aluminate Hydride for CO₂ Hydroboration Catalysis: Mechanistic Insights and Countercation Influence on Catalytic Performance

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 22, 2025

The present study details the synthesis and characterization of a robust, monomeric Al–H aluminate supported by tridentate tris-phenolate ligand, isolated as [2][Li(THF)4] [2][N(nBu)4] salts, which were then exploited CO2 hydroboration catalysts. As initial reactivity studies, it was observed that nucleophilic anion in [2][C] (C = countercation [Li(THF)4]+ or [N(nBu)4]+) reacts fast with CO2, to afford corresponding Al-formate complexes [3][C], structurally characterized. Such anions potential reduction Salts [2–3][N(nBu)4] are efficient robust catalysts presence pinBH Me2S-BH3 hydroborane sources selectively formate-equivalent methanol-equivalent products (TON up 1920), depending on reaction conditions nature countercation. deduced from detailed DFT calculations, [3]− acts catalyst (for borane activation) but also an electrophile (through AlOCO carbon) allowing activation/functionalization thus catalysis occur, process thermodynamically driven stability products. anionic [2]− aluminates, resulting enhanced nucleophilicity (vs neutral analogues), may be crucial for catalytic activity. In contrast, according calculations performed model pinBH, processing via Al–O/B–H σ-bond metathesis appears kinetically unfavored. proposed mechanism involving electrophilic/nucleophilic dual-activation mode rationalizes importance [C]+ [2-3][C] activity selectivity, demonstrated higher performance vs [2][Li(THF)4].

Language: Английский

Hydro-coupling of isocyanates promoted by 1,2-bis(arylimino)acenaphthene aluminum hydrides

Dalton Transactions, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

This work demonstrates unusual hydro-coupling of isocyanates using paramagnetic acenaphthene-1,2-diimine aluminum hydrides.

Language: Английский