Table 3.

Assignments of the lignin ¹³C–¹H correlation peaks in the 2D-HSQC spectra of whole cell walls and of the corresponding isolated milled lignins from cork, phloem and xylem of Quercus suber L.

Label	δC/δH	Assignment
Bβ	53.1/3.43	Cβ–Hβ in phenylcoumaran substructures (B)
Cβ	53.5/3.05	Cβ–Hβ in β–β′ resinol substructures (C)
−OCH3	55.6/3.73	C−H in methoxyls
Aγ	59.4/3.40 and 3.72	Cγ–Hγ in β–O–4′ substructures (A)
Dβ	59.5/2.75	Cβ–Hβ in in 5-5′ (dibenzodioxocin) substructures (D)
Iγ	61.3/4.08	Cγ–Hγ in cinnamyl alcohol end-groups (I)
Bγ	62.6/3.67	Cγ–Hγ in phenylcoumaran substructures (B)
A′γ	63.5/3.83 and 4.30	Cγ–Hγ in γ-acylated β–O–4′ substructures (A′)
I′γ	64.3/4.63	Cγ–Hγ in γ-acetylated cinnamyl alcohol end-groups (I′)
Cγ	71.0/3.83 and 4.19	Cγ–Hγ in β–β′ resinol substructures (C)
Aα(G)	71.0/4.73	Cα–Hα in β–O–4′ substructures (A) linked to a G-unit
Aα(S)	71.7/4.83	Cα–Hα in β–O–4′ substructures (A) linked to a G-unit
Fβ′	79.4/4.10	Cβ′–Hβ′ in spirodienone substructures (F)
A′β(G)	80.7/4.51	Cβ–Hβ in γ-acetylated β–O–4′ substructures linked to a G-unit (A′)
Fα	81.2/5.01	Cα–Hα in spirodienone substructures (F)
Dα	83.0/4.82	Cα-Hα in 5-5′ (dibenzodioxocin) substructures (D)
Fα′	83.6/4.68	Cα′–Hα′ in spirodienone substructures (F)
Aβ(G)	83.7/4.26	Cβ–Hβ in β–O–4′ substructures (A) linked to a G unit
Cα	84.7/4.64	Cα–Hα in β–β′ resinol substructures (C)
Dβ	85.2/3.85	Cβ-Hβ in 5-5′ (dibenzodioxocin) substructures (D)
Aβ(S)	85.8/4.09	Cβ–Hβ in β–O–4′ substructures linked (A) to a S unit
Bα	86.8/5.43	Cα–Hα in phenylcoumaran substructures (B)
S2,6	103.7/6.68	C2–H2 and C6–H6 in etherified syringyl units (S)
J2,6(S)	106.2/7.02	C2-H2 and C6-H6 in sinapaldehyde end-groups (J)
S′2,6	106.3/7.32 and 7.20	C2-H2 and C6-H6 in Cα-oxidized syringyl units (S′)
G2	110.8/6.96	C2–H2 in guaiacyl units (G)
FA2	111.1/7.25	C2-H2 in ferulates (FA)
J2(G)	112.5/7.30	C2–H2 in conyferaldehyde end-groups (J)
F2′(S)	113.5/6.25	C2′–H2′ in spirodienone substructures (F)
FAβ	113.5/6.27	Cβ–Hβ in ferulates (FA)
G5/G6	115.0/6.74	C5–H5 and C6–H6 in guaiacyl units (G)
G6	118.7/6.77	C5–H5 inguaiacyl units (G)
J6(G)	118.8/7.30	C6–H6 in conyferaldehyde end-groups (J)
F6′(S)	118.9/6.06	C6′–H6′ in spirodienone substructures (F)
FA6	123.3/7.10	C6–H6 in ferulate (FA)
Jβ	126.3/6.76	Cβ–Hβ in cinnamyl aldehyde end-groups (J)
H2,6	128.0/7.23	C2,6–H2,6 in p-hydroxyphenyl units (H)
FAα	144.4/7.41	Cα–Hα in ferulates (FA)
Jα	153.4/7.61	Cα–Hα in cinnamyl aldehyde end-groups (J)