摘要
A series of ruthenium hydride compounds containing bidentate pyrrole-imine ligands were synthesized and characterized and their properties were fully studied. Reacting [C 4 H 3 NH-(2-CH=N-R) (L 1 H, R = CH 2 -2-furanyl; L 2 H, R = CH 2 -morpholine; L 3 H, R = CH 2 -2-pyridyl) with one equivalent of n-BuLi afforded the corresponding lithium reagents (LiL 1 ∼LiL 3 ). Combining RuHCl(CO)(PPh 3 ) 2 with LiL 1 ∼LiL 3 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 [C 4 H 3 NLi-(2-CH=N- t Bu)] (LiL 4 ) with one equivalent RuHCl(CO)(PPh 3 ) 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 L 4 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.