3 years ago

Syntheses of Heteroleptic Amidinate Strontium Complexes Using a Superbulky Ligand

Syntheses of Heteroleptic Amidinate Strontium Complexes
Using a Superbulky Ligand
Christian Färber, Jürgen Pahl, Sjoerd Harder, Benjamin Freitag
Strontium complexes are presented with two different bulky amidinate ligands (Am): tBuC(N-DIPP)2 (DIPP = 2,6-diisopropylphenyl), abbreviated here as tBuAmDIPP, and (p-tolyl)C(N-Ar)2 (Ar = 2,6-Ph2CH-4-iPr-phenyl) abbreviated here as pTolAmAr‡. The amidine tBuAmDIPP-H was deprotonated by Sr[N(SiMe3)2]2 in benzene at 60 °C. Although the product, tBuAmDIPPSrN(SiMe3)2, could be characterized by NMR, attempts to isolate it led to ligand scrambling via a Schlenk equilibrium. Reaction of in situ prepared tBuAmDIPPSrN(SiMe3)2 with PhSiH3 gave PhH2SiN(SiMe3)2 and presumably the intermediate tBuAmDIPPSrH, but the latter is not stable and the homoleptic complex (tBuAmDIPP)2Sr was isolated and structurally characterized. Deprotonation of the bulkier amidine pTolAmAr‡-H with Sr[N(SiMe3)2]2 needed forcing conditions, inevitably giving rise to deprotonation of the Ph2CH substituent as well. Reaction of pTolAmAr‡-H with the less bulky and less basic Sr[N(SiHMe2)2]2, however, gave the heteroleptic product pTolAmAr‡SrN(SiHMe2)2, which has been structurally characterized. The latter was also at 60 °C stable toward ligand scrambling. Reaction with PhSiH3 did give hydride exchange, but the product pTolAmAr‡SrH decomposed even at −30 °C. Instead, an amidinate complex with a deprotonated Ph2CH substituent was isolated and structurally characterized (7). The latter catalyzed the intramolecular alkene hydroamination.

Publisher URL: http://dx.doi.org/10.1021/acs.organomet.7b00871

DOI: 10.1021/acs.organomet.7b00871

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.