Amine-boranes reactions promoted by lanthanide(II) ions
Vladislava A Kirkina1, Alexander A Kissel1, Alexander N Selikhov1,2
1A. N. Nesmeyanov Institute of Organoelement Compounds (INEOS) of Russian Academy of Sciences, 28 Vavilov str., GSP-1, B-334, Moscow, 119991, Russia. shu@ineos.ac.ru.
Lanthanide(II) complexes catalyze amine-borane dehydrogenation, a novel finding. These complexes, featuring Ln(II) species, act as dehydrocoupling intermediates in this catalytic process.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Lanthanide Chemistry
Background:
- Amine-borane complexes are crucial in catalysis.
- Dehydrogenation reactions are important for hydrogen storage and chemical synthesis.
- Lanthanide(II) species have shown limited catalytic activity.
Purpose of the Study:
- To investigate the catalytic activity of lanthanide(II) complexes in amine-borane dehydrogenation.
- To explore the mechanism of dehydrocoupling intermediates.
Main Methods:
- Synthesis of lanthanide(II) complexes [{(p-tBu-C6H4)2CH}2M·L] (M = Yb, Sm; L = (DME)2, TMEDA).
- Protonation of M(II)-C bonds with amine-borane (HNR1R2BH3).
- Reaction of amidoborane complexes with excess dimethylamine borane (HNMe2BH3).
Main Results:
- Catalytic activity in amine-borane dehydrogenation demonstrated for Ln(II) species for the first time.
- Formation of amidoborane complexes [M(NR1R2BH3)2L] via protonation of M(II)-C bonds.
- Transformation to [NMe2BH2NMe2BH3]− derivatives under excess HNMe2BH3, serving as dehydrocoupling intermediates.
Conclusions:
- Ln(II) complexes represent a new class of catalysts for amine-borane dehydrogenation.
- The identified amidoborane complexes and their derivatives are key intermediates in the catalytic cycle.
- This study expands the scope of lanthanide catalysis in dehydrogenation reactions.
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