Stepwise magnetic behavior of the liquid crystal iron(III) complex |
| |
Authors: | N E Domracheva V E Vorob’eva A V Pyataev R A Manapov E M Zueva M S Gruzdev U V Chervonova |
| |
Institution: | 1.Kazan Physical-Technical Institute, Kazan Scientific Center,Russian Academy of Sciences,Kazan,Russia;2.Kazan (Volga region) Federal University,Kazan,Russia;3.Kazan National Research Technological University,Kazan,Russia;4.G. A. Krestov Institute of Solution Chemistry,Russian Academy of Sciences,Ivanovo,Russia |
| |
Abstract: | EPR and Mössbauer spectroscopy is used to study a new liquid crystal complex of iron(III) with a Schiff base: 4,4′-dodecyloxybenzoyloxybenzoyl-4-oxysalicylidene-2-aminopyridine with a PF 6 ? counterion. It is shown that Fe(III) ions exist only in the high-spin (HS, S = 5/2) state. It is found that under the influence of temperature the system demonstrates the stepwise behavior of the product of the integrated intensity of EPR lines (I) and temperature (proportional to χ T, where χ is the magnetic susceptibility) with an inflection point at ~80 K. Above 80 K a new EPR spectrum is detected due to the excited S = 2 state and the formation of dimeric molecules (through oxygen bridges) with a strong intramolecular antiferromagnetic exchange interaction J 1 = 162.1 cm?1. Below 80 K iron(III) complexes are organized in 1D chains where the exchange value J 2 = 2.1 cm?1. At 80 K there is a structural phase transition in the system: the transition from a 1D chain organization of HS Fe(III) centers to dimeric molecules. Based on quantum chemical calculations a model of the binuclear iron(III) complex is proposed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|