Catenane correlation

Figure 5. Correlations between the reduction potentials of two electron acceptor macrocycles and their catenanes with an electron donor crown ether. Black and white circles refer to reduction of bipyridinium and bis(pyridinium)ethylene units, respectively processes marked with involve two electrons.

Figure 13.34 Correlation between the half-wave reduction potentials of catenane 394+ and of its tetracationic ring component. Circles and squares correspond to the reduction of bipyridinium and /ra 1v-bis(pyridinium)ethylene units, respectively.

Three doubly spin-labelled [2]catenanes with different sizes were studied by 4-pulse DEER.52 The experimental distribution of interspin distances was compared with a theoretical pair-correlation function computed based on geometrical constraints. In chloroform solution the medium and large catenanes were close to fully expanded, but in glassy o-terphenyl they were partially collapsed. For the smaller catenane there was a higher population of shorter interspin distances, which was attributed to interactions between unsaturated sections of the molecule. 

Figure 10. Correlation diagram for the electrochemical reduction of cyclophane [2]rotaxane 3", and [2]catenane 8 + (MeCN, 25 °C, potentials versus SCE) bielectronic processes are indicated [23],...

The NMR spectrum of the free [2]catenane SO is dramatically different from that of its parent Cu(I) complex 49 ". Dipolar correlations show that upon demetalation the catenane goes from an extended conformation to a more compact one in which the two porphyrins are closer together on average but have no significant interactions, as represented in Fig. 20. 

Fig. 9.2 Correlation between the halfwave reduction potentials (Sy/j) of the bipyridinium (open circle) and bis(pyridinium)ethylene (filled circle) units in free 2 cyclophane and in l catenane...

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