A switchable iron-based coordination polymer toward reversible acetonitrile electro-optical readout

Abstract

A novel non-porous molecular-based acetonitrile sensor is reported. This material shows a reversible magneto-structural transition under desorption/absorption of acetonitrile involving a drastic switch in its optical and electronic properties.

Biased Spin-State Energetics of Fe(II) Molecular Complexes within Density-Functional Theory and the Linear-Response HubbardUCorrection

“…[1][2][3][4][5][6][7][8] Achieving such a description with chemical accuracy appears today as a significant challenge for ab initio methods with strong implications in future assistance and guidance of experimental efforts devoted to the (i) development and optimization of catalytic reactivity and the (ii) design of novel spin crossover (SCO) complexes. The vast majority of SCO materials, which are of great interest for applications such as molecular spintronics, molecular electronics, sensors and actuators, [9][10][11][12] are octahedrallycoordinated Fe(II)-based molecular complexes. For these complexes, the thermodynamics of the spin transition (i.e.…”

Tunable Proton Conductivity and Color in a Nonporous Coordination Polymer via Lattice Accommodation to Small Molecules

“…An offset DC bias voltage is set to V = 1 V. A sharp peak centered at T c (aceto) = 310 K appears in G by increasing the temperature, as previously observed in DC conductance measurements after the release of acetonitrile molecules, see schematics in Figure 1a . [ 47 ] The conductance at the peak, normalized to the dimensions of the crystals is ≈10 μ S cm ‐1 . These values are similar to those typically found in the literature [ 42 , 46 ] The initial increment in G can be fitted to an Arrhenius law for thermally activated transport (see Figure 1d and additional examples in Section S2, Supporting Information).…”

“…(CH 3 CN) 2 complex, hereafter 1 ·2CH 3 CN). [ 47 ] The Fe core is hexacoordinated with two water, two acetonitrile, and two pyrazine molecules forming closely packed 1D coordination chains. Besides, 1 ·2CH 3 CN contains two uncoordinated acetonitrile molecules coupled to the polymer chains through hydrogen bonds formed with the coordinated water molecules.…”

“…No weakly bonded water molecules are found in the lattice structure (see Section 1 in the Supporting Information for the structure). The 1 ·2CH 3 CN crystals were able to reversibly modify their electro‐optical properties by desorption of the uncoordinated acetonitrile molecules from the crystal lattice [ 47 ] (see schematics in Figure 1 a ). A sharp peak in the DC electrical current was reported to coincide in temperature with a crystal phase transition and subsequent breaking of van der Waals bonds of interstitial acetonitrile molecules.…”

“…A sharp peak in the DC electrical current was reported to coincide in temperature with a crystal phase transition and subsequent breaking of van der Waals bonds of interstitial acetonitrile molecules. [ 47 ] The conductance peak was accompanied by a color change of the crystal from light yellow to orange. The mechanism able to translate the phase transition to a sharp change in the current was however not understood.…”