Effect of Metal Dilution on the Thermal Spin Transition of [Fe_xZn_1–x(bapbpy)(NCS)₂]

Abstract

This study reports on the effects of zinc dilution on the structure and magnetic properties of the mononuclear two-step spin-crossover compound [Fe(bapbpy)(NCS) 2 ] (1; bapbpy = N6, N6Ј-di(pyridin-2-yl)-2,2Ј-bipyridine-6,6Ј-diamine). According to powder X-ray diffraction and infrared spectroscopy, the phase of compound 1 is retained in the zincdiluted samples when x Ͼ 0.53. At higher dilutions (i.e., when x Ͻ 0.53), the phase of compound 3 gradually takes

Highly Ordered, Self‐Assembled Monolayers of a Spin‐Crossover Complex with In‐Plane Interactions

“…Overall, the iron‐to‐iron intermolecular distances might be longer in 2 than in [Fe(bapbpy)(NCS) 2 ], which would explain the lack of cooperativity for this compound. This effect is similar to the metal dilution effect shown in [Fe x Zn 1− x (bapbpy)(NCS) 2 ], [52] where increasing concentrations of the magnetic inert Zn ions in the crystal lattice causes the iron centers to become further away from each other, resulting in a lowered cooperativity for SCO.…”

Variations to Spin Crossover in [FexZn(1−x)(Me1,3bpp)2(ClO4)2] molecular alloys examined by Magnetometry and Single Crystal X-Ray Diffraction

“…To put into perspective the linear decrease of TSCO observed in the series 3x, we have compared the relative decrease TSCO, defined as TSCO(x)/TSCO(x = 1), with four other molecular SCO systems for which doping into the Zn analogue has been studied. These include a similar bis-tris-imine coordination environment in [FexZn1-x(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) [53], a tris-amineimine chromophore in [FexZn1-x(2-pic)3]Cl2•EtOH (2-pic = 2-picolylamine) [35] and two systems with axial thiocyanate donors and either a twice bis-imine equatorial environment, in [FexZn1-x(phen)2(NCS)2] (phen = 1,10-phenantroline) [33], or a tetra-imine chelate, in [FexZn1-x(bapbpy)(NCS)2]•3DMF (bapbpy = N6,N6'-di(pyridin-2-yl)-2,2'-bipyridine-6,6'diamine) [63]. Remarkably, and despite different temperature ranges for the SCO as well as different types of SCO processes, the data of all five series of doped materials follow approximately a common master linear trend, best described by TSCO(x) = 62.3+37.1x.…”

Metal Substitution Effect on a Three-Dimensional Cyanido-Bridged Fe Spin-Crossover Network

“…In addition, with an increasing x value, spin crossovers become more gradual. According to the reported observations [16][17][18][19][20][21][22][23][24][25], these results are explained as follows. Since the ionic radii of Co(II) HS (0.75 Å) is closer to Fe(II) HS (0.78 Å) than Fe(II) LS (0.61 Å) [55], the spin-crossover from Fe(II) HS to Fe(II) LS becomes unfavorable, leading to a decrease of the spin transition temperature.…”

“…This phenomenon can be modulated by various physical and chemical stimulations (e.g., light, pressure, temperature, vapor molecule, and metal substitution), and it has potential for sensor and memory applications [14,15]. To control the spin-crossover behavior, the metal substitution effect on the spin-crossover behavior for some Fe II spin-crossover materials has been investigated [16][17][18][19][20][21][22][23][24][25].…”