Gradual Thermal Spin-Crossover Mediated by a Reentrant Z′ = 1 → Z′ = 6 → Z′ = 1 Phase Transition

Abstract

/0000-0002-5249-9523 and Halcrow, MA orcid.org/0000-0001-7491-9034 (2017) Gradual thermal spin-crossover mediated by a reentrant Z' = 1 → Z' = 6 → Z' = 1 phase transition. Inorganic Chemistry, 56 (6).

Spin-State Patterning in an Iron(II) Tripodal Spin-Crossover Complex

“…These results are consistent with those of Halcrow et al 19 The two-step character arises from a change in slope over the region of ca. 190–170 K, representative of an intermediate plateau (IP) (however with declining rather than stable χ M T values).…”

“…Illustrating the immense interest in the field, we had been simultaneously and independently investigating the same material. Our results are largely consistent with those of Halcrow et al 19 Here, we present complementary results, including the high-resolution crystal structure of the intermediate phase (190 K), that clarify the symmetry-breaking nature of the phase transition: variable-temperature magnetic susceptibility measurements with slow scan rates, and variable-temperature X-ray photoelectron spectroscopy (VT-XPS).…”

“…Whereas the HS and LS structures are consistent with Halcrow’s results, the previous report on the structure of the symmetry-broken intermediate phase ( Z ′ = 6, compared to Z ′ = 1 at room and low temperature) determined at 175 K “has relatively low precision, reflecting the size of the model and significant cation and anion disorder, which was only partly resolvable”. 19 With careful attention to obtaining a suitable crystal, we were able to obtain data of high quality and without substantial disorder.…”

The number and shape of lattice solvent molecules controls spin-crossover in an isomorphous series of crystalline solvate salts

“…S22, ESI ‡). 19,20 The intermediate phase (triclinic, P% 1, Z = 4) retains the same space group as the initial phase, but with a doubled unit cell volume containing 1 : 1 mixture of high-and low-spin molecules. These are segregated into alternating layers within the crystallographic (010) plane (Fig.…”

“…However, that does not rule out a symmetry breaking near 190 K in that crystal, which could occur locally but without long-range order in the lattice. 20 ) materials from magnetic susceptibility data (Fig. 2 and 3 and ESI; scan rate 5 K min À1 ) geometries, as above.…”