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Tetranuclear Strontium and Barium Siloxide/Amide Clusters in Metal‐Ligand Cooperative Catalysis
Author(s) -
Freitag Benjamin,
Stegner Phillip,
Thum Katharina,
Fischer Christian A.,
Harder Sjoerd
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800231
Subject(s) - chemistry , hydroamination , alkene , hydrosilylation , isostructural , medicinal chemistry , substituent , catalysis , ligand (biochemistry) , pyridine , amide , stereochemistry , organic chemistry , polymer chemistry , crystal structure , biochemistry , receptor
One‐pot reaction of 2,6‐ i Pr 2 ‐aniline (DIPP‐NH 2 ) with (Me 2 SiO) 3 and Sr[N(SiMe 3 ) 2 ] 2 (SrN′′ 2 ) gave a tetranuclear cluster consisting of four dianions [OSiMe 2 N‐DIPP] 2– and four Sr 2+ ions solvated each by one THF ligand. The general applicability of this method was investigated by variation of amine and metal. Anilines with smaller substituents led to insoluble uncharacterized coordination polymers, whereas bulkier anilines gave soluble product mixtures that could not be purified. Primary alkylamines neither led to isolable products. Introduction of a t Bu group in para ‐position of DIPP‐NH 2 , however, gave an isostructural cluster with increased solubility. Similar clusters could be obtained with barium. Both, the Sr and Ba clusters, were found to be active catalysts for a wide range of transformations: intramolecular alkene hydroamination, alkene hydrophoshination, pyridine hydroboration, pyridine hydrosilylation, and alkene hydrosilylation. The Ba catalysts were generally more active than the Sr catalysts. The t Bu‐substituent in para ‐position also had an accelerating effect, which is likely due to improved solubility.