Spin‐Crossover Nanocrystals with Magnetic, Optical, and Structural Bistability Near Room Temperature

Abstract

In Wasser‐in‐Öl‐Mikroemulsionen wurden Nanokristalle des porösen dreidimensionalen Koordinationsnetzwerks [Fe(pz)Pt(CN)4]⋅n H2O (pz=Pyrazin; n≤2.5) synthetisiert. Die tensidfreien Nanokristalle geben bereitwillig Wasser ab. So werden wasserfreie Verbindungen erhalten, deren elektronische Bistabilität sich in einem Farbwechsel (siehe Bild) nahe Raumtemperatur äußert.

Influence of Hydrogen Bonding on the Hysteresis Width in Iron(II) Spin‐Crossover Complexes

“…[8] Of the possible types of ST (gradual, abrupt, with hysteresis, stepwise, incomplete), much of the interest is focused on the bistability in highly cooperative systems (hysteresis or memory effect) as such compounds can exist in two different electronic states depending on the history of the system. In this regard, we recently characterised an iron(II) SCO complex with a 70 K wide thermal hysteresis loop around room temperature based on a 2D network of hydrogen bonds between the complex molecules {compound 1-[FeL1(HIm) 2 ]}.…”

Bidirectional Chemo‐Switching of Spin State in a Microporous Framework

“…[7] In particular, {Fe(pz) [Pt(CN) 4 ]} (1) displays a first-order spin transition with approximately 25 K wide hysteresis (critical temperatures: T c fl = 285 K and T c › = 309 K), and its SCO properties are retained in a thin film [7b,c] or nanocrystals. [8] Based on ab initio X-ray powder diffraction results of dihydrated 1 (1·2 H 2 O), we found that the framework provides two guestinteractive sites, one between the pz-bridges (site A) and another between the four-coordinate Pt centers (site B). Furthermore, the pz-bridges are provided with rotational freedom in the framework.…”

Modulare Synthese von funktionellen nanoskaligen Koordinationspolymeren

“…[15] [Co III (3,5-dbsq)(3,5-dbcat)]-Nanopartikel mit Low-Spin-Konfiguration konnten durch thermische Einwirkung in ein [Co II (3,5-dbsq) 2 ]-Material im HighSpin-Zustand überführt werden. Gaspar, Real et al beschrieben die Synthese von Dimetall-NMOFs aus [Fe(pz)Pt(CN) 4 ]·x H 2 O (pz = Pyrazin, x = 1 oder 2.5), die nahe der Raumtemperatur magnetische, optische und strukturelle Bistabilität zeigen [21] und somit interessante Kandidaten für aktive Komponenten in Multifunktionsmaterialien, insbesondere für Speicherbausteine sind.…”