Laser powered homogeneous decomposition of selenophene and tellurophene

Homogeneous decomposition of gaseous selenophene and tellurophene C4H4M (M = Se, Te) has been investigated by using technique of IR laser-induced (SF6-photosensitized) pyrolysis and trapping experiments with D2. The decomposition is controlled by cleavage of both CM bonds and yields elemental heteroatom along with 1-buten-3-yne, ethyne, ethene and buta-1,3-diene (major products, selenophene) or 1-buten-3-yne (major product, tellurofene). The observed mass effect of M on the products distribution and the preference of 1-buten-3-yne over ethyne in both decompositions is in keeping with transient butadienediyl C4H4 diradical and more feasible 1,3-H shift rather than β-cleavage (via cyclobutadiene) in this species.