We report the results of density functional theory (DFT) calculations of the 57Fe Mössbauer quadrupole splittings ΔEQ and isomer shifts δFe of both the high-spin (HS) and low-spin (LS) states of two typical spin crossover complexes: the six-coordinate species cis-bis(thiocyanato)bis(1,10-phenanthroline)iron(II), (Fe(phen)2(NCS)2; S = 2 or 0) and the five-coordinate system, [N,N′-ethylenebis(salicylideniminato)]nitrosyl iron(II), (Fe(salen)-(NO); S = 3/2 or 1/2). There is excellent agreement between the experimental data and the theoretical calculations. The wave functions derived are used to clarify some aspects of the differences between the HS and LS electronic states of these materials, and they put on a firm theoretical foundation the use of Mössbauer spectroscopy to investigate spin-crossover complexes.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry