Nitrosonium complexes 2.2 paracyclophane

To date the structure and reactivity of numerous complexes derived from aromatic compounds and nitrosonium cation have been studied (5, 56-63). However, relatively few studies are available on the nitrosonium complexes of cyclophanes (5, 57, 59, 61, 62), cf ref. (63). The interaction of [2.2]paracyclophane with nitrosonium tetrachloroaluminate was studied by H and 13C NMR spectroscopy using deuterium isotope perturbation technique (64). It was found that the resulting nitrosonium complexes containing one (25) or two NO groups (26) are involved in fast interconversion (on the NMR time scale) (Scheme 17). 

Figure 2. Optimized structures of the nitrosonium complexes of [2.2]paracyclophane at DFT/3Z. Distances are in angstroms.

The affinity of [2.2]paracyclophane for nitrosonium cation is much greater than that of para-xylene, presumably owing to stacking interaction between the aromatic rings in the 7i-complex. Low isotope effect on the aromatic carbon... 

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