Addition of 1,12-dilithiotriphenylenediyl to L2NiCl2 (L = PEt3) gives the nickelacycle L2Ni(1,12-triphenylenediyl), which decomposes to a dimer (L2Ni2C36H20) containing two coupled triphenylene moieties with a new C−C bond. Thermolysis of the dimer completes the coupling, yielding a chiral tetraphenylene, while alkyne addition leads to cleavage of the newly formed C−C bond of the dimer and cycloaddition of the alkyne to the triphenylene fragment.

Treatment of the four-membered platinacycle L2Pt(1,8-naphthalendiyl) (1) or the five-membered platinacycle L2Pt(1,12-triphenylendiyl) with excess PhCCPh at 120-150 degrees C gives the coupling products 1,2-diphenylacenaphthalene or 4,5-diphenylbenzo[e]pyrene and the alkyne complex L2Pt(eta2-PhCCPh). Both reactions show an accelerating rate, which has been traced to catalysis of the reaction by colloidal platinum formed by the reaction of O2 with L2Pt(eta2-PhCCPh).

Thermal decomposition of Cp2ZrMe(1-bromobenzocyclobutenyl) yields the η2-cyclobutadiene complex Cp2Zr(η2-benzocyclobutadiene)(PMe3), which cycloadds alkenes, nitriles, and t-BuNC, in the last case giving a novel diamino−Dewar-naphthalene complex.

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