However, for a more detailed analysis, other characterisation techniques need to be utilized. 13 C solid-state NMR was used to further characterise the functionalization of the carbon materials with anthraquinones (Figure ). The prominent broad peak at ca. 125 ppm comes from sp2-hybridised carbons in the graphene-like sheets within the carbon material, with some contribution from the C=C carbons originating from anthraquinone for the functionalized samples (Figure .1, Figure .2). In the anthraquinone-functionalized carbons, a broad resonance is also visible in the 174-180 ppm range, which was assigned to the anthraquinone carbonyl carbon and further demonstrates that anthraquinone molecules were successfully grafted onto the CMK-3, BP-1300 and YP-80F carbon materials. It was previously shown that ring current effects in carbon materials shield nuclei located close to the carbon aromatic rings -anthraquinone closer to carbon surfaces should have a lower C chemical shift. Therefore, the C chemical shifts of the carbonyl group can be used as a probe for the grafting of anthraquinone in the carbon pores as: lowered chemical shift values indicate increased interactions with the carbon ring currents, here corresponding to anthraquinone grating into smaller pores, to a first approximation. Here, the carbonyl chemical shifts can be compared to that of neat 2-aminoanthraquinone as a reference value at 181.6 ppm, as a chemical shift difference ∆𝛿 (Figure .2). In addition, the Gaussian broadening of the NMR line-shapes characterizes the heterogeneity of ring current effects experienced by the anthraquinone molecules and therefore are expected to correlate with pore size distributions in which the grafted quinones are located. Our NMR data together with pore size distributions obtained from gas sorption data supported this hypothesis. Gas sorption measurements suggested that anthraquinones grafted in the micropores for f-YP80F, and indeed this sample has the lowest C=O chemical shift (174.3 ppm, ∆𝛿 = -7.3 ppm, 11.7 ppm width). The ∆𝛿 value of -7.3 ppm is larger than that measured previously for freely diffusing molecules in the pores of this material (~-4.5 ppm), supporting the idea that the anthraquinone molecules are bound to the pore structures where they experience larger ring current shifts. On the other hand, for f-CMK-3, a smaller shift difference is observed for the grafted anthraquinones (179.7 ppm, ∆𝛿 = -1.9 ppm, 4.7 ppm width), supporting grafting in the mesopores. The ∆𝛿 value observed here is comparable to that seen for freely diffusing molecules adsorbed in the pores of CMK-3 (~-1.5 ppm), consistent with the presence of anthraquinones that are located several angstroms away from the carbon pore walls. f-BP-1300, which has both micropores and mesopores, showed a carbonyl peak (175 ppm, 19.4 ppm width) at an intermediate chemical shift, with a significantly increased line width consistent with anthraquinone grafting in a broad range of chemical environments, including within both mesopores and micropores.