Dinitrogen complexes alkylation

Acids, acyl, and aroyl halides all react with [ReCl(N2)(PMe2Ph)4]. However, protonation occurs at the metal to give the hydride [ReClH(N2)-(PMe2Ph)4], whereas slow acylation and aroylation occur at the end nitrogen atom. Interestingly, this latter reaction is the reverse of the preparation of the rhenium dinitrogen complexes. Alkyl halides do not react with rhenium complexes of dinitrogen. 

Niobium, tris(diethyldilhiocarbamato)oxy-stereochemistry, 1,82 structure, 1, 83 Niobium, tris(oxa ato)oxy-stereochcmistry, 1, 82 Niobium, tris(phcnylcncdirhio)-structure, 1, 63 Niobium alanate, 3, 685 Niobium complexes alkyl alkoxy reactions, 2, 358 amides, 2,164 properties, 2, 168 synthesis, 2, 165 applications, 6,1014 carbamicacid, 2, 450 clusters, 3, 672,673,675 hexamethylbenzene ligands, 3, 669 cyanides synthesis, 2, 9 p-dinitrogen, 3, 418 fluoro... 

Simple alkyl chlorides react with these dinitrogen complexes to give only frans- MCl2(dppe)2]. Activated alkyl chlorides such as ethyl chloroacetates react to give the corresponding diazenido complexes (58, 59). 

SCHEME 4. Mechanism of the alkylation of electron-rich dinitrogen complexes (phosphine ligands omitted for clarity). 

The increased basicity of a ligand when coordinated to the heavier metals in a transition metal triad has been appreciated for some time (311). This is manifest in (1) the rate of alkylation of alkyldiazenido complexes (kw/kMo = 5.4) (93), and (2) the rate of formation of hydra-zido(2-) complexes by the reaction of dinitrogen complexes with acid, in methanol ( w// Mo = 9.2 x 102) (186), and in tetrahydrofuran (kw/ kMo = 29-85, dependent upon the acid and substrate employed) (187). Clearly the electron-releasing capability of the metal has conflicting influences on the rate, but as in Section VI,El the basicity influence dominates. 

A bis(i7-cyclopentadienyl)titanium(III) alkyl dinitrogen complex was prepared by reaction of [(i7-C5H5)2TiCl]2 with isopropylmagnesium chlo-... 

This compound is a precursor to a wide variety of three- and four-coordinate iron (II) complexes, including alkyl, aryl, hydride, oxo, hydroxo, amido, and fluoride complexes.3,4 Reduction to an iron(I) dinitrogen complex provides a pathway to iron(I) complexes.4... 

We conclude this survey of the types of reaction that were discovered by mentioning the variety of products obtained from reaction of a,cu-dibromides, Br(CH2) Br, with truns-[M(N2)2(dppe)2], which depended on the value of n. As we have already noted, for n = 1, a diazoalkane complex was formed for M = Mo. However, for M = W the complex [(WBr(dppe)2 2(jU-N2CH2N2)] was also isolated. In general, more than one type of complex was always formed, the long-chain diazenido-complexes evidently acting as alkyl bromides and attacking further dinitrogen complexes. ... 

In the next section, we will discuss several alkyldiazenido complexes which were obtained by alkylation of dinitrogen complexes with strongly nucleophilic alkylation reagents. At least one such case is also known for aryldiazenido complexes. Sellmann and Weiss (1978) showed that a (dinitrogen)manganese complex reacts with phenyllithium (see Sect. 3.3). 

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