Iron ansa half sandwich complexes bearing a bridging distannadiyl moiety

Insertion of Chalcogens and Bis(tert-butylisonitrile)palladium(0) into a Strained Ruthenium Half-sandwich Complex

“…and characterized in solution by multinuclear NMR spectroscopy. All NMR data meet our expectations and are comparable to those of previously reported related iron complexes [39].…”

“…Such complexes play an important role in catalytic transformations, for example in palladium-catalyzed cross-coupling [42] or distannylation reactions [43]. Similar reactivity patterns have already been disclosed by us in the case of other tinbridged ansa half-sandwich complexes of group 6 and [40] and an analogous iron ansa half-sandwich complex bearing a sulfur atom in the bridging moiety [39]. In conclusion, we have shown that the insertion of chalcogens (O, S, Se) into a highly reactive distanna bridge of an ansa ruthenium half sandwich leads to expansion of the bridging moiety with a significant decrease of ring strain.…”

“…1). As reported for analogous compounds with iron as the central metal [39], the insertion leads to an almost complete relief of ring strain, as evidenced by the tetrahedral Ru-Sn1-S1 angle of 109.6(1) ( Table 1). Furthermore, the loss of rigidity causes a shortening of the Ru-Sn1 and C1-Sn2 bond lengths in comparison with those of the precursor complex 1, a finding that is consistent with that already made for the corresponding iron compound [39].…”

“…The second route disclosed by our group is based on a one-step synthesis starting from bimetallated halfsandwich complexes and salt metathesis with suitable bridging units [35,38]. The resulting ansa halfsandwich complexes show high ring strain, which facilitates insertion reactions [35,39] as well as ringopening polymerization reactions, as shown by Pannell and coworkers [29,30] …”

StrainedansaHalf-Sandwich Complexes of Ruthenium and Osmium and a Non-Iron Metallopolymer by Ring-Opening Polymerization

“…In contrast to these precursors, ansa half-sandwich complexes, which have likewise been found to form organometallic polymers by ring-opening reactions, are far less developed. While initial studies of ansa half-sandwich complexes were limited to carbon-bridged species, more recent work established a series of complexes featuring metals from groups 6, 8, and 10 bridged by silicon and tin moieties. − Given the potential of these heavier carbon congeners to facilitate the ROP of ansa sandwich complexes, it is surprising that the only known examples of organometallic polymers composed of half-sandwich repeating units feature iron as the central transition metal. The iron-containing precursors to these materials, reported by Pannell et al, featured both carbon–silicon and silicon–silicon bridges that readily underwent ROP at ambient temperature, yielding polymers with molecular weights up to 175000. ,, Herein we report the synthesis of the first non-iron ansa half-sandwich complex that provides a metallopolymer upon thermally-induced ROP.…”