Spin-Crossover in a Pseudo-tetrahedral Bis(formazanate) Iron Complex Raquel Travieso-Puente J. O. P. Broekman Mu-Chieh Chang Serhiy Demeshko Franc Meyer Edwin Otten 10.1021/jacs.6b01552.s004 https://acs.figshare.com/articles/dataset/Spin_Crossover_in_a_Pseudo_tetrahedral_Bis_formazanate_Iron_Complex/3188563 Spin-crossover in a pseudo-tetrahedral bis­(formazanate) iron­(II) complex (<b>1</b>) is described. Structural, magnetic, and spectroscopic analyses indicate that this compound undergoes thermal switching between an <i>S</i>=0 and an <i>S</i>=2 state, which is very rare in four-coordinate complexes. The transition to the high-spin state is accompanied by an increase in Fe–N bond lengths and a concomitant contraction of intraligand N–N bonds. The latter suggests that stabilization of the low-spin state is due to the π-acceptor properties of the ligand. One-electron reduction of <b>1</b> leads to the formation of the corresponding anion, which contains a low-spin (<i>S</i>=1/2) Fe­(I) center. The findings are rationalized by electronic structure calculations using density functional theory. 2016-04-14 00:00:00 Fe spectroscopic analyses structure calculations bond