Niobium #eta#-cyclopentadienyl compounds with imido and amido ligands derived fromtert-butylamine

摘要

The niobium #eta#-cyclopentadienyl compounds with imido and amido ligands [Nb(#eta#-C_5H_5)(NH~tBu)(NH~tBu)Cl] 1, ~*[Nb(#eta#-C_5H_5)(NH~tBu)(NH~tBu)~nBu] 2, [Nb(#eta#-C_5H_5)(NH~tBu)(NH~tBu)_2] 3, Nb(#eta#-C_5H_5)(NH~tBu)(NH~tBu)Me] 4. [Nb(#eta#-C_5H_5)(#eta#~1-C_5H_5)(NH~tBu)] 5, [Nb{(#eta#-C_5H_5)CMe_2(#eta#~1-C_5H_4)}(N~tBu)(NH~tBu)] 6, [Nb(#eta#-C_5H_5){N(C_6H_3~iPr_2-2, 6)}(NH~tBu)Cl] 7, ~* [Nb(#eta#-C_5H_5){N(C_6H_3~iPr_2-2, 6)}(NH~tBu)Me] 8, [Nb(#eta-C_5H_5)(N~tBu)(NEt_2)Cl] 9 and [Nb(#eta#-C_5H_5)(N~tBu)(NH~tBu)(NEt_2)] 10 have been prepared (~* indicates the crystal structure has been determined). A corrrelation between the chemical shift of the NH proton and the value of #DELTA##delta# measured between the #alpha# and #beta# carbons of the tert-butyl groups of the amido ligands is discussed in relation to the degree of electron donation from the amido ligand to the miobium centre.