Iron (II) isothiocyanate complexes with substituted pyrazines: Experimental and theoretical views on their electronic structure

Synthesis, structural, magnetic. Mossbauer and thermal studies of isothiocyanate iron (II) complexes with substituted pyrazines (iodo-, bromo- and amino-derivatives) are discussed here. Complexes with iodo- and bromo-derivatives were found to have the composition [Fe(Ipz)(2)(SCN)(2)(H2O)(2)]center dot 2Ipz (1) and [Fe(Brpz)(2)(SCN)(2)(H2O)(2)]center dot 2Brpz (2), whereas in the case of amino-functionalized pyrazine the formation of [Fe(NH(2)pz)(4)(SCN)(2)] (3) was observed. 3D organization of the molecular complexes is stabilized within different hydrogen, halogen and lone pair-it interactions. Spin state of iron (II) ions in 1-3 was determined as high spin by Mossbauer and magnetic measurements. DFT calculations for the obtained iron (II) complexes were carried out to analyze the electronic structure and to support experimentally measured Mossbauer parameters with theoretical predictions. (C) 2014 Elsevier Ltd. All rights reserved.