Hydrazido complexes structure

A general approach to rhenium hydrazido complexes is the reaction of oxo or chloro compounds with organohydrazines as has been demonstrated in an early report with the synthesis of [Re NNC(Ph)0 Cl2(PPh3)2] (310), " the molecular structure of which was solved in 1988. A detailed study on [Re(NNR)Cl2(PPh3)2] complexes with R = COPh or phthalazine shows that the course of subsequent reactions is governed both by the nature of the donor group R responsible for chelate closure and by the type of donor ligand introduced. No simple substitution chemistry has been observed for R = phthalazine. The benzoyl compound... 

The chemical and structural relationships between hydrazine and hydrazido complexes and between hydroxylamine and hydroxylamido complexes have been recently reviewed.510... 

Hydrazido(2 —) complexes are most prevalent within group VI although there are to date no reported hydrazido complexes of chromium. Representative examples of known structure are shown in Table 16. Sulfur coligands predominate reflecting the metal-sulfur coordination in nitrogenase and the participation of hydrazide ligands in dinitrogen chemistry. 

We have made several other V" complexes by displacing the hydrazine ligand in [V(N2H4)(NS3)] with Cl , N3 CN , MeCN or CNBu , and have prepared a series of imido-complexes [V(NAr)(NS3)] (Ar = various substituted phenyl groups), and of hydrazido-complexes [V(NNR R )(NS3)] (R R = methyl or phenyl) from reactions of [V(0)(NS3)] with aryl isocyanates or 1,1-disubstituted hydrazines, respectively. Structural studies on several of these compounds always reveal trigonal bipyramidal coordination about the V atom. The V-N distance in the V(NS3) system, as a result of the shape of the NS3, is sensitive to... 

Recrystallization of 40d in the presence of A TV-dimethylbydrazine affords the N,N-dimethylhydrazine-bridged dinuclear vanadinm(V) hydrazido complex 40d-DMH-40d. The single-crystal X-ray structure determination of 40d-DMH-40d confirms that two 40d units are bridged by 7V,A -dimethylhydrazine to form the 2 1 complex in anti-configuration, wherein each vanadium center is a hexacoordi-nate geometry (Fig. 3.30b) [114]. This hydrazido complex 40d-DMH-40d has the near-linear V(l)-N(2)-N(3) angles of 171.8(7) and 174.0(7)° with the V(l)-N(2) distances of 1.663(7) and 1.690(7) A, respectively. 

A very helpful attempt to classify organohydrazido and related complexes of Group 7 elements by analysis of their X-ray crystal structure data has been undertaken in a review which also covers the structural chemistry of this type of complexes up to the year 1996. The convention applied in this article will also be used here to classify hydrazido and related complexes. 

Their proton base strengths are less than that of the dinitrogen complex, but greater than that of the hydrazido(2 -) complexes.139 Their structures are likely to be similar to those of the alkyldiazenido complexes discussed below, that is trans octahedral with a linear MoNN system and NNH = 120°, but definite evidence is lacking. 

---