TRIS(PHENANTHROLINE)IRON(II) BIS(CITRATO)STANNATE(IV): SYNTHESIS, MOLECULAR AND CRYSTALLINE STRUCTURE

Abstract

A synthesis technique was developed and a new complex [Fe(рhen)3][Sn(HCit)2]∙2H2O (I) (phen is 1,10-phenanthroline and Н4Сit is citric acid) was obtained. Based on the data of elemental analysis, the molar ratio Sn: citrate: Fe: phen = 1:2:1:3 is realized in complex I. The presence of a vacant carboxyl group –COOH in molecule I is confirmed with the band in the IR-spectra ν(С=О) = 1708 сm–1. Unlike the IR-spectrum of citric acid, νas(СОО–), νs(СОО–), ν(С–О) bands of the alcoholate type in the region of 1083 сm–1 and stretching vibrations of the Sn – O bond appear in the IR-spectrum of I. The presence of the stretching vibrations in the range of 1300–1600 сm–1, 1000–1500 сm–1 and 700–1200 сm–1, which is specific for an aromatic molecules, confirms the presence of 1,10-phenanthroline in I. X-Ray analysis showed that I is a coordination compound of the cation-anionic type with the [Fe(phen)3]2+ as cation and the [Sn(HCit)2]2- as anion. The coordination polyhedron of Sn(IV) in the complex anion is a distorted octahedron formed by three pairs of oxygen atoms of two tridentate chelating ligands НCit3-. In cations, Fe atoms are coordinated by three phen molecules. In one of the cations, one phen molecule is disordered in two positions with the same occupation. This leads to the formation of two types of cation: A (without disordering of phen molecules) and B (with disordering of phen molecules). The coordination polyhedron of Fe(II) in both types is a distorted octahedron. Anions, cations, and also water molecules form alternating layers parallel to the crystallographic plane bc. Layers can be divided into three types: layers, which contain only anions and water molecules connected with intermolecular hydrogen bonds; and ones which contain only type A cations or only type B cations.

Keywords

• станум
• ферум(ii) сульфат
• лимонна кислота
• 1,10-фенантролін
• координаційні сполуки
• кристалічна структура