A series of [2.2]paracyclophane/dehydrobenzo[14]annulene (PC/DBA) hybrids (hydrocarbons 5, 6, 9, 10 b, and 10 c), [2.2]paracyclophane/dehydro[14]annulene (PC/DA) hybrids (7 and 8) and suitable model systems (11, 12, and 33) has been synthesized. Comparison of the electronic absorption spectra in each series of compounds provides further insight into the global communication between the decks in the [2.2]paracyclophane unit.

The synthesis of seven ethynyl[2.2]paracyclophanes is described. The five diethynyl derivatives 4,5-diethynyl[2.2]paracyclophane (12), pseudo-gem-(13), pseudo-ortho-(14), pseudo-meta-(15), and pseudo-para-diethynyl[2.2]paracyclophane (16), the tetraethynyl compound 4,7,13,16-tetraethynyl[2.2]paracyclophane (17), and for comparison the mono-ethynylated hydrocarbon 4-ethynyl[2.2]paracyclophane (11) have been prepared. The structures of these new building blocks for carbon rich systems were determined by the usual analytical and spectroscopic methods.

The synthesis of [2.2]paracyclophane/dehydro[14]annulene hybrids 1 and 2 is reported. Comparison of the proton NMR spectra of 1 and 2 with their open precursors and with related model compounds reveals the pronounced effect of macrocycle formation upon the cyclophane protons H15/H16, which lie above the shielding cone of the diatropic [14]annulene moiety. [structure: see text]

The preparation of 11 from 4,5-diethynyl[2.2]paracyclophane (9) is described.

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