The Ab Initio study of the structure of the [Fe2(Htrz)6(trz)3]BF4 and the [Fe4(Htrz)10(trz)5](BF4)3 complexes at the low spin and the high spin states Asep Wahyu Nugraha *1), Ani Sutiani 1), Djulia Onggo 2), and Muhamad A Martoprawiro 2)
Physical Chemistry Division Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan, Jalan Willem Iskandar V Medan Estate Medan 20222 Indonesia
Inorganic and Physical Chemistry Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10 Bandung 40132 Indonesia
Abstract
The aim of this study was to determine the structure of the [Fe2(Htrz)6(trz)3]BF4 and the [Fe4(Htrz)10(trz)5](BF4)3 complexes in the low spin state and high spin state. Determination of the complex structure using the visualization of the results of computational chemistry calculations. Computational chemistry calculations using the function basis set UHF 6-31G(d). The Fe(II) 1,2,4 H-triazole complex has a polymeric structure, so the computational calculations used molecular modeling with two and four Fe(II) ions. Models of the complex compounds with two Fe(II) ions was the [Fe2(Htrz)6(trz)3]BF4 complex and the models with four Fe(II) ions was the [Fe4(Htrz)10(trz)5](BF4)3 complex. The results of this study showed that the distance between Fe (II) ions in the [Fe2(Htrz)6(trz)3]BF4 complex at the low spin and the high spin states respectively, were 3.792 and 4.043, while in the [Fe4(Htrz)10(trz)5](BF4)3 complex at the low spin and the high spin states respectively, were 3.823 3.839 and 3.995 4.008. The distance between Fe (II) ions at high spin state is longer than the distance between Fe(II) ions at low spin state. The Fe-N bond lengths on the [Fe2(Htrz)6(trz)3]BF4 complex at the low spin was 2.047 2.123 and the high spin states was 2.173 2.372, whereas in the [Fe4(Htrz)10(trz)5](BF4)3 complex at the low spin states was 2.064 2.228 and the high spin states was 2.140 2.502. The length of the FeN bond at the high spin state is longer than the length of the Fe-N bond at the low spin state.
Keywords: complex structure, the 1,2,4 H-triazole Fe(II), computational chemistry, and visualization
