Alkynylselenolatoalklidynes and related unsaturated organoselenium ligands

In contrast to the organometallic chemistry of carbon monoxide, that of carbon monosulfide is somewhat limited, whilst there are very few examples (all mononuclear) of complexes involving carbon monoselenide. Continuing our studies on the chemistry of alkynylselenoethers (RSe–C≡CR’) and alkynylselenolates (LnM–Se–C≡CR’), we have now turned our attention to the study of the previously unknown alkynylselenolatoalkylidyne class of compounds, LnM≡C–Se–C≡CR. In addition to simple cluster building reactions of these unusual unsaturated species that ultimately leave the LnM≡C–Se–C≡CR spine intact, we have also encountered remarkably facile reactions that result in regioselective cleavage of one C–Se bond to provide the first examples of ‘isoselenocarbonyls’, i.e., bimetallic species in which a CSe diatomic unit bridges two distinct metals. The inner coordination geometry of one such complex, [MoPt(μ-CSe)(C≡CtBu)(CO)2(PPh3)2{HB(pzMe2)3}], is shown.