Chapter 31

Assuming the molecular formula of 9 is established as \(\mathrm{C}_{40} \mathrm{H}_{60} \mathrm{~N}_{6} \mathrm{Zr}_{2}\), explain how the proposed structure is consistent with \({ }^{15}\) N NMR spectra as follows. Made with \({ }^{15} \mathrm{~N} \equiv{ }^{14} \mathrm{~N}, 9\) shows three widely separated resonance lines of equal intensity. However, when 9 is made with \({ }^{15} \mathrm{~N} \equiv{ }^{15} \mathrm{~N}\), two of the peaks become doublets with a spacing of \(6 \mathrm{~Hz}\).

Explain how an alkene-metathesis catalyst might convert a cycloalkene into (a) a long-chain unsaturated polymer, (b) a mixture of large-ring polymers, and (c) a catenane (interlocking carbon rings like two links in a chain).