Exploring the metallochromic behavior of pentacyanidoferrates in visual, electronic and Raman spot tests

JORGE S. SHINOHARA, DANIEL GRASSESCHI, SABRINA N. ALMEIDA, HENRIQUE E. TOMA
2019 Anais da Academia Brasileira de Ciências  
How to cite: ShINOhARA JS, GRASSeSChI D, AlmeIDA SN AND TOmA he. 2019. exploring the metallochromic behavior of pentacyanidoferrates in visual, electronic and Raman spot tests. An Acad Bras Cienc 91: e20180315. Abstract: Pentacyanidoferrate(II) complexes of aromatic N-heterocycles, such as 4-cyanopyridine, exhibit characteristic colors and strong metallochromism associated with the donor-acceptor interactions of the metal ions with the cyanide ligands. In the presence of transition metal ions
more » ... sition metal ions insoluble polymeric complexes are formed, displaying bright yellow, red, brown and green colors with zinc(II), nickel(II), copper(II) and iron(III) ions, respectively. Such metallochromic response is better observed on filter paper, allowing applications in analytical spot tests. The effects can be explored visually and probed by means of modern instrumental facilities, including spectrophotometric and resonance Raman techniques. In this way, by using the cyanopyridinepentacyanidoferrates, the Prussian Blue test for ferric ions can be extended to the entire row of transition metal elements, providing a new and modern insight of such classical Feigl's spot tests.
doi:10.1590/0001-3765201920180315 fatcat:2rscdjbokrfvlbg73taud4e65i