Bis(η-cyclopentadienyl)imido compounds of niobium

Abstract

The compound [Nb(q-C,H5),(NBut)CI] has been synthesised and its crystal structure determined. It is the precursor for the new compounds [Nb(q-C,H5),(NBut)Me],[Nb(q-C5H5),(NBut)Br], [Nb(q-C5H5),(NBut) (C,H,CH,)]and [Nb(q-C5H5),(NBut)(o-C,H5)], and the hydrido derivative [Nb(q-C5H5)2(NBUt) HI.We have been interested in studying compounds containing both the q-cyclopentadienyl ligand and organoimido ligands :NR since we anticipate that this ligand combination will give rise to interesting reactivities. We and others have reported compounds with this ligand combination for compounds of the early transition metals, including molybdenum, tungsten, niobium3 and t a n t a l ~m . ~ Recently we described the first example of a bis(q-cyclopentadieny1)imido derivative of niobi ~m . ~Here we describe further chemistry of bis(q-cyclo-pentadieny1)imido derivatives of niobium.

Sandwich and Half‐Sandwich (Imido)niobium Complexes

“…[24,25,30] We have expanded this field by the preparation of the following new [53] The synthetic pathway to these complexes is determined by the reaction of the appropriate magnesium reagent MgRCl with the corresponding metallocene complex [Equation (8)]. (8) In the 1 H NMR spectra of the ethyl complexes 16 and 19 ( Figure 6) the ethyl group displays an A 3 BC pattern with typical values of J AB ϭ 7.0, J AC ϭ 7.5, J BC ϭ 14.0 Hz, similar to those reported previously in two ethyl complexes of niobium.…”

Alkyl–η2-alkene niobocene and tantalocene complexes with the allyldimethylsilyl–η5-cyclopentadienyl ligand: synthesis, NMR studies and DFT calculations

“…15 it was reported that this is also the region where the hydride signal of terminal Nb-H 16 and Ta-H 17 bonds are observed for this type of dicyclopentadienyl imido complexes. The difference between the 13 C quaternary and methyl carbon resonances of the tertbutylimido group is 30.8 ppm suggesting a linear disposition of the Nb-N-tBu ligand in complex 15.…”

Non‐Innocent Behaviour of Imido Ligands in the Reactions of Silanes with Half‐Sandwich Imido Complexes of Nb and V: A Silane/Imido Coupling Route to Compounds with Nonclassical SiH Interactions

“…[24] In the 1 H NMR spectra of silyl hydride complexes 3 the hydride resonates in the range 1.65-3.00 ppm, down-field shifted as a result of the anisotropy of the Nb=N bond. [25] The hydride bands in the IR spectra are observed in the range 1616-1681 cm…”