Synthesis, Spectra, and Thermal Analysis

Hydrazinium metal sulfate hydrazines of the formula (N2H5)2M(S04)2-3N2H4 are prepared by reaction of the corresponding ammonium metal sulfate hexahydrates with stoichiometric amounts of hydrazine hydrate  

The reaction is instantaneous with the evolution of ammonia and color change. After complete removal of ammonia, the products are washed with ethanol and diethyl ether, and dried over P2O5. However, the above reaction with Mn gives only the hydrazinium metal sulfate (N2H5)2Mn(S04)2 and not the hydrazinium metal sulfate hydrazine as expected. The corresponding hydrazinium metal sulfate hydrazine of copper is also not obtained because of its instant reduction to copper metal on addition of hydrazine hydrate. 

Hydrazinium zinc and cadmium sulfates can also be prepared by dehydrazination of the corresponding hydrazine complexes  

Hydrazinium metal sulfate complexes show IR (infrared) absorption at around 990-1005 cm, characteristic of j n-n of the coordinated N2H5 cation and splitting of 1 3 (1100cm ) and 1 4 (600cm ) bands of S04 indicating the presence of bidentate sulfate groups (Table 5.1) 

575s 610 Asymmetric bending and N—H deformation 

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The synthesis of the complex is followed by the most important step of characterization of the complex. The composition and the structural features of both the ligand and complex have to be established before embarking on further studies. There exist many methods by which the composition and structural features of the complexes are studied. Some of the methods are (i) elemental analysis, (ii) X-ray crystallography, (iii) UV-Vis absorption spectra, (iv) infrared spectroscopy, (v) Raman spectroscopy, (vi) thermal methods of analysis such as thermogravimetry, differential thermal analysis, (vii) nuclear magnetic resonance spectroscopy (proton, multinuclear), (viii) electrospray mass spectrometry. Depending upon the complexity of the system, some or all the methods are used in the studies of complexes. 

Budukuley, J.S. and Patil, K.C. (1990) Synthesis, infrared spectra and thermoanalytical properties of transition metal sulphite hydrazine hydrates. Journal of Thermal Analysis, 36, 2583-2592. 

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