Dimeric aluminum-phosphorus compounds as masked frustrated Lewis pairs for small molecule activation

作者：Roters Steffi; Appelt Christian; Westenberg Hauke; Hepp Alexander; Slootweg J Chris; Lammertsma Koop^*; Uhl Werner

来源：Dalton Transactions, 2012, 41(30): 9033-9045.

DOI：10.1039/c2dt30080j

Hydroalumination of aryldialkynylphosphines RP(C C-Bu-t)(2) (R = Ph, Mes) with equimolar quantities of diethylaluminum hydride afforded mixed alkenyl-alkynyl cyclic dimers in which the dative aluminum-phosphorus bonds are geminal to the exocyclic alkenyl groups. Addition of triethylaluminum to isolated 1 (R = Ph) or to the in situ generated species (R = Mes) caused diethylaluminum ethynide elimination to yield the arylethylphosphorus dimers 2 and 3. These possess a chair-like Al2C2P2 heterocycle with intermolecular Al-P interactions. The boat conformation (4) was obtained by the reaction of Bu-t-P(C C-Bu-t)(2) with di(tert-butyl) aluminum hydride. Despite being dimeric, 2 behaves as a frustrated Lewis pair and activates small molecules. The reaction with carbon dioxide gave cis/trans isomeric AlPC2O heterocycles that differ only by the configuration of the exocyclic alkenyl unit. Four isomers resulted from the reaction with phenyl isocyanate. This is caused by cis/trans isomerization of the initial C=O adduct and subsequent rearrangement to the AlPC2N heterocycle, being the C=N adduct.

• 出版日期2012