New Selenola to-Bridged Clusters of Iron and Nickel; the Structures of [Fe_(12)(SePh)_(24)] and [Na_2(POPh_3)_6][Ni_(20)Se_(12)(SeMe)_(10)]

摘要

The reactions of phosphane complexes of transition metal halides with E(SiMe_3), (E = S, Se, and Te) icud to a great number of multinuclear clusters, whose frameworks contain sections from the structures of binary chalcogenides. which arc surrounded by a protecting shell of PR_3 ligands (R = organic group). We have now investigated whether PhSeSiMe, and NaSeMc can also be used for the synthesis of these types of clusters. As an example, we found that the Fe_(12) cluster 1 is formed almost quantitatively in the reaction of Fed, with PPh, and PhSeSiMe_3 [Eq. (a)]. In THF and toluene at room temperature, only amorphous powder is obtained, some of which is pyrophoric. In contast, 1 enstaliizes in the form of shiny black needles within 12 h when a suspension nf FeCl_3 and PPh_3 in dichloroethane is carefully covered with a layer of PhSeSiMe. Compound 1 decomposes readily on warming in organic solvents releasing elemental selenium.