Fig. 8.

Influence of relevant reaction parameters on the yield and size distribution of giant calixarenes. a, b, c evolution of the ¹H NMR spectra (DMSO-d6; hydroquinone-type protons area) of crude products obtained with different bases (one-step process used for all examples); d, e, f evolution of the ¹H NMR chemical spectra of the hydroquinone-type protons of crude products obtained using increasing concentrations of CsOH (one-step process); g and h SEC comparison of two crude samples obtained using different base/phenol ratio. Number of PRUs shown in the boxes. The green asterisks are highlighting bis(homooxa) p-(benzyloxy)calix[4]arene. ¹H NMR (DMSO-d6) comparison between low (i) and high (j) base/phenol ratio, and between low (j) and high (k) refluxing times. Green asterisks: p-(benzyloxy)bishomooxacalix[4]arene; red asterisks: linear oligomers