Structure–reactivity correlations in new W(IV) and Nb(IV) silicon-bridged ansa-metallocene hydrides

W(IV) and Nb(IV) derivatives: [W(L1)MeI] (1), [W(L1)MeH] (2) and [W(L1)O] (3), [W(L2)Cl2] (4), [W(L2)H2] (5), [W(L2)H3][BF4] (6), [Nb(L2)Cl2] (7) and [Nb(L2)(η2-BH4)] (8), where L1 = [(η-C5H4)2SiMe2]2− and L2 = [(η-C5H3TMS)2SiMe2]2−, have been prepared and characterised. The crystal structures of compounds 5 and 8 have been determined. Thermodynamic parameters for the elimination of methane from compound 2 have been evaluated based on 1H NMR studies in C6D6. Trimethylsilyl substituents on the cyclopentadienyl rings appear to moderate the structural and dynamic properties of the silicon-bridged ansa-tungstenocenes.

New W(IV) and Nb(IV) derivatives: [W(L1)MeI] (1), [W(L1)MeH] (2) and [W(L1)O] (3), [W(L2)Cl2] (4), [W(L2)H2] (5), [W(L2)H3][BF4] (6), [Nb(L2)Cl2] (7) and [Nb(L2)(η2-BH4)] (8) (where L1 = [(η-C5H4)2SiMe2]2− and L2 = [(η-C5H3TMS)2SiMe2]2−) have been prepared and their structural and dynamic properties have been investigated.Figure optionsDownload as PowerPoint slide