Fig. 4

2D 1H–13C HSQC spectra of the long-chain 13C-labeled lignin oligomer models in the CSP experiment. a Superimposed 2D 1H–13C HSQC spectra of the aromatic region in compound 4(Arβ) (50 μM) in the presence (red) and absence (blue) of 350 μM TrCBM1. b A magnified image of the HSQC signals from the C 5 positions. c Superimposed 2D 1H–13C HSQC spectra of aliphatic regions and methoxy groups in 4(Arβ), 4(α), and 4(m) (50 μM) in the presence (red) and absence (blue) of 350 μM TrCBM1