sentence: Cyclic oligomers had distinctive appearances in H NMR spectra : for centrosymmetric macrocyles 8 – 13 these were represented by relatively simple spectra of the repeat unit compared to more complex spectra , as be expected for linear oligomers 14 – 18.2.3 Uncatalysed 1,3 - dipolar cycloaddition of azido-alkyne-containing galactose monomer 7 .