Inhaltszusammenfassung

The square-pyramidal clusters Fe3(CO)9(mu3-PR)(mu3-X) (1) (R = (i)Pr, (t)Bu; X = Se, Te) react on photochemical activation with alkynes to give the compounds Fe3(CO)9[(R)P-C(R')=C(R'')-X] (2). The clusters 2 contain the alkyne in a position bridging the main group centres of 1. With terminal alkynes 1 reacts selectively in such a way that in the products 2 the CH group of the alkyne is bonded to the PR fragment. Treatment of Fe3(CO)9(mu-P(i)Pr)(mu3-Se) (1a) with phenylacetylene as the termina...The square-pyramidal clusters Fe3(CO)9(mu3-PR)(mu3-X) (1) (R = (i)Pr, (t)Bu; X = Se, Te) react on photochemical activation with alkynes to give the compounds Fe3(CO)9[(R)P-C(R')=C(R'')-X] (2). The clusters 2 contain the alkyne in a position bridging the main group centres of 1. With terminal alkynes 1 reacts selectively in such a way that in the products 2 the CH group of the alkyne is bonded to the PR fragment. Treatment of Fe3(CO)9(mu-P(i)Pr)(mu3-Se) (1a) with phenylacetylene as the terminal alkyne yields Fe2(CO)6[((i)Pr)P-C(H)=C(Ph)-Se] (3) as an additional product. 3 has one Fe(CO)3 group less than 2a. The analogous reaction of the cluster Fe3(CO)9(mu3-P(t)Bu)(mu3-Se) (1b) with the phosphaalkyne (t)BuC=P does not lead to a product which, in the place of the alkyne in 2, would contain its heteroanalogon (t)BuC=P. The cluster Fe3(CO)7Se(P(t)Bu)((t)BuC=P)3 (4) is formed instead, in which the constituents of lb incorporate an unconventional trimer of (t)BuC=P. Reaction of Fe3(CO)9Se(P(t)Bu)((t)BuC=CH) (2c) with (t)BuC=P leads to the cluster Fe3(CO)7Se(P(t)Bu)((t)BuC=CH)(mu3-P-C(=C=O)((t)Bu)] (5), in which a (t)BuC=P entity is transformed into a bridging mu3-P-C(=C=O)((t)Bu) group. These conclusions are supported by spectroscopic, analytical and electrochemical data as well as by X-ray analyses. » weiterlesen» einklappen

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