Hydrazine ligands

Hydrazine and substituted-hydrazine complexes of the type ZrOX2(NH2NHR)4 (R = H, Me or Ph X = Cl, Br, I, NCS or N03) have been synthesized by addition of six equivalents of the hydrazine to an ethanol solution of the appropriate zirconyl salt. An IR band at —970 cm-1 assigned to v(N—N) indicates the presence of bidentate chelating or bridging hydrazine ligands these complexes may be polymeric since they are insoluble in common organic solvents.56... 

Addition of alcoholic N2H4-H20 to an aqueous solution of Cr(C104)3 affords a violet crystalline compound of composition Cr(N2H4)2(C104)3.61Q The IR spectrum of the product shows split absorption bands at 1100 and 630 cm-1 characteristic of chelating C104 and a band at 950 cm-1 characteristic of a monodentate hydrazine ligand. On this basis structure (141) is proposed for this complex. 

This hydrogen transfer is essentially an intramolecular acid-base reaction. The hydrogen of the coordinated alcohol function is acidified by coordination to the copper center whilst the hydrazine ligand possesses basic properties. The elimination of the hydrazine substituent is irreversible under these neutral conditions. Indeed, in the absence of excess base, DBADH2 is unable to displace the alkoxide ligand from the copper complex G. 

The p-fluorophenylhydrazine complex is stable to air and moisture, but the hydrazine ligand is easily displaced by nucleophiles such as chloride ion. The N-bonded protons readily exchange with D20 and with D2 but are much less acidic than that of the p-fluorophenyldiimide complex.4 Prolonged hydrogenation cleaves the N—Pt bond to give the arylhydrazine and [PtHCl P (CsHs) 2]. 

Figure 2. Perspective view of the structure of 1. Both positions of the disordered bridging hydrazine ligand are shown. The ethyl groups of the dedtc ligands and the H atoms on the N2Hk groups have been omitted...

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... 

Hydrazine ligands are well established and behave similarly to ammonia. In addition to being unidentate they can act as bridges between two metals. There are no authenticated cases of sideways or J -bound N2H4, but two cases of ff -organohydrazine ligands have been reported, e.g. [Mo( =-C5 H5 )(N0)I(NH2 NHPh)] +... 

The same colors and shapes have been published by Lao [17] for products containing two hydrazine ligands. 

Fe(C6Hs NHNH2)2Cl2 room 6.36 Farad bridging hydrazine ligand octahedral coordination suggested 74N20... 

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