Metal isothiocyanate hydrazines

In another method, metal powders free from an oxide film are added directly to a solution of N2H5SCN in hydrazine hydrate. Owing to the high acidic nature of hydrazinium thiocyanate formed in situ, the metal powders dissolve instantaneously with the liberation of hydrogen gas, forming metal isothiocyanate hydrazines ... 

Interestingly, in all these synthesis methods, although one starts with the thiocyanate salt, with hydrazine as one of the ligands, the metal chelates to the N atom of the anion to form complexes of the rearranged isothiocyanate type. This formation of metal isothiocyanate hydrazines is confirmed by chemical analysis and infrared spectra (Table 3.1). 

Figure 3.2 Polymeric structure of metal isothiocyanate hydrazine. Adapted from Ref. [8] with permission from the Indian Academy of Sciences 1983.

Table 3.2 Color of metal isothiocyanate hydrazine complexes and magnetic moment data.

All the complexes initially lose hydrazine, forming the metal isothiocyanates ... 

The synthesis of metal hydrazine complexes with thiocyanate or isothiocyanate as anions can be carried out by the following methods [8]. In the first case, stoichiometric quantities of metal(II) salts like chlorides or sulfates of Mn, Fe, Co, Ni, Zn, and Cd in an alcohol-water mixture (1 1 by volume) are added to hydrazinium thiocyanate. The latter is metathet-ically formed by the reaction of NH4SCN -I- N2H4 H2O (1 1 mole ratio) (Chapter 2) ... 

The metal-nitrogen frequencies z m-n of hydrazine and z m-n of isothiocyanate are observed at around 400 and 350 cm, respectively. Since two different frequencies are observed, the two metal-nitrogen... 

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