Treatment of the chloro(fulvalene)zirconium(III) compound [Zr(η5-C5H5)(μ-Cl)]2[μ-(η5,η5-C10H8)] with an equimolar amount of azobenzene in toluene, under extremely anhydrous conditions, gives the μ-[bis(imido)] derivative [Zr(η5-C5H5)(μ-NPh)]2[μ-(η5,η5-C10H8)] (1). However, when this reaction is carried out under insufficiently dry conditions a mixture of the previously reported μ-oxo complex [Zr(η5-C5H5)Cl]2(μ-O)[μ-(η5,η5-C10H8)] and 1,2-diphenylhydrazine is obtained. When the chloro(fulvalene)zirconium(III) compound reacts with benzo[c]cinnoline the μ-(η2,η2-N,N-hydrazido) complex [Zr(η5-C5H5)Cl]2[μ-(NC6H4C6H4N)][μ-(η5,η5-C10H8)] (2a) is obtained, which rearranges to the thermodynamically more stable 2b. Addition of an equimolar amount of RNC (R = nBu, C6H11) to a toluene solution of [Zr(η5-C5H5)(μ-Cl)]2[μ-(η5,η5-C10H8)] gives [Zr(η5-C5H5)Cl]2(μ-CNR)[μ-(η5,η5-C10H8)] [R = nBu (3), C6H11 (4)]. Reaction of [Zr(η5-C5H5)Cl]2(μ-CNtBu)[μ-(η5,η5-C10H8)] with 1 equiv. of PhCH2MgCl or (PhCH2)2Mg(THF)2 afforded the monobenzyl derivatives [Zr(η5-C5H5)]2(CH2Ph)(Cl)(μ-CNtBu)[μ-(η5,η5-C10H8)] (5 and 6). When this reaction was carried out with 2 equiv. or an excess of PhCH2MgCl, a mixture of the monobenzyl and dibenzyl compounds [Zr(η5-C5H5)]2(CH2Ph)(Cl)(μ-CNtBu)[μ-(η5,η5-C10H8)] (5) and [Zr(η5-C5H5)(CH2Ph)]2(μ-CNtBu)[μ-(η5,η5-C10H8)] (7) is obtained. Similar reactions with 1 or 2 equiv. of (CH3)3SiCH2Li afford a mixture of the monoalkyl and dialkyl compounds [Zr(η5-C5H5)]2[CH2Si(CH3)3](Cl)(μ-CNtBu)[μ-(η5,η5-C10H8)] (8) and {Zr(η5-C5H5)[CH2Si(CH3)3]}2(μ-CNtBu)[μ-(η5,η5-C10H8)] (9) compounds. Moreover, methylation of [Zr(η5-C5H5)Cl]2(μ-CNnBu)[μ-(η5,η5-C10H8)] gives the analytically pure tetramethyl derivative [Zr(η5-C5H5)(CH3)]2(μ-CNnBu)[μ-(η5,η5-C10H8)] (10), whereas [Zr(η5-C5H5)Cl]2(μ-CNC6H11)[μ-(η5,η5-C10H8)] reacts with MeLi to give a mixture of the monomethyl derivatives [Zr(η5-C5H5)]2(CH3)(Cl)(μ-CNC6H11)[μ-(η5,η5-C10H8)] (11 and 12), as well as the dimethyl compound [Zr(η5-C5H5)(CH3)]2(μ-CNC6H11)[μ-(η5,η5-C10H8)] (13). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)