Geometric isomerization and geometry controlled catalytic alcohol aminations of ruthenium hydride compounds containing bidentate pyrrolyl-imines

Yong Jie Li, Hsuan Ting Lai, Ching Han Hu, Jie Hong Chen, Chia Her Lin, Jui Hsien Huang

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Abstract

A series of ruthenium hydride compounds containing bidentate pyrrole-imine ligands were synthesized and characterized and their properties were fully studied. Reacting [C4H3NH-(2-CH=N-R) (L1H, R = CH2-2-furanyl; L2H, R = CH2-morpholine; L3H, R = CH2-2-pyridyl) with one equivalent of n-BuLi afforded the corresponding lithium reagents (LiL1∼LiL3). Combining RuHCl(CO)(PPh3)2 with LiL1∼LiL3 in THF at 0 °C with stirring at room temperature for 12 h generated pure trans-Pyr-Ru-H 1–3 in moderate yields after repeated fractional recrystallization. When the reactions were performed at reflux temperature, pure cis-Pyr-Ru-H 1–3 were obtained by fractional recrystallization in relatively high yields. A thermal isomerization study showed that pure cis-Pyr-Ru-H 1–3 and trans-Pyr-Ru-H 1–3 can be interconverted in THF after refluxing and equilibrium was attained. Reacting a bulkier ligand [C4H3NLi-(2-CH=N-tBu)] (LiL4) with one equivalent RuHCl(CO)(PPh3)3 at room temperature afforded only cis-Pyr-Ru-H 4 after purification. No trans-Pyr-Ru-H 4 was observed, indicating the bulkier t-butyl group of the L4 ligand altered the stability of cis- and trans-Pyr-Ru-H 4. A catalytic alcohol amination study showed the cis forms of Pyr-Ru-H were the active catalysts for converting benzyl alcohol to N-benzylaniline.

Original languageEnglish
Article number120957
JournalJournal of Organometallic Chemistry
Volume902
DOIs
Publication statusPublished - 2019 Dec 1

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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