Assignment and conformational investigation of asymmetric phenylindenylidene ruthenium complexes bearing N,O-bidentate ligands

作者：Hendrickx P M S^*; Drozdzak R; Verpoort F; Martins J C

来源：Magnetic Resonance in Chemistry, 2010, 48(6): 443-449.

DOI：10.1002/mrc.2599

• NMR
• (1)H
• (13)C
• ruthenium
• indenylidene
• complex
• olefin
• metathesis
• chemical exchange
• rotational isomerism

The NMR conformational study of three asymmetric phenylindenylidene ruthenium complexes 4.1-4.3, is presented. Complete (1)H and (13)C assignments could be obtained for 4.1-4.3 in benzene solution from multiple 2D homonuclear and heteronuclear NMR techniques. Our NMR analysis shows that each complex exists as a 55:45 mixture of two rotational isomers in slow exchange on the NMR chemical shift timescale. They are shown to be related by a 180 degrees flip of the indenylidene ligand along the Ru=CR bond. Both rotational isomers can be discriminated by means of NOEs contacts between the various ligands coordinating to the Ru. By matching these stereospecific assignments to the chemical shift, a chemical shift based fingerprint of the isomers that may allow straightforward assignment of future asymmetric phenylindenylidene ruthenium complexes is proposed.

• 出版日期2010-6