Chugaev discovered that
dimethylglyoxime forms a scarlet solid upon reaction with nickel(II) ions. This reaction was one of the first "spot tests" for a metal ion. An adherent to the theories of
Alfred Werner, Chugaev made several contributions to the chemistry of platinum. The salt [Pt(NH3)5Cl]Cl3 containing the chloropentammineplatinum(IV) ion, is called "Chugaev's salt". Other complexes prepared in his laboratory include [Pt(
SEt2)4][PtCl4], [Pt(NH3)5OH]Cl3, [Os(
SC(NH2)2)6]Cl3.H2O. Chugaev also studied complexes of
hydrazine. One of his complexes, since also called Chugaev's salt, was the product of the reaction of platinum(II) salts with
methyl isocyanide and hydrazine. After many decades, this compound was shown to be a carbene complex, probably the first metal carbene complex ever reported. ==Contributions to organic chemistry==