Thermally Induced Valence Tautomeric Transition in a Two‐Dimensional Fe‐Tetraoxolene Honeycomb Network

Abstract

A novel tetraoxolene‐bridged Fe two‐dimensional honeycomb layered compound, (NPr4)2[Fe2(Cl2An)3] ⋅2 (acetone)⋅H2O (1), where Cl2Ann−=2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinonate and NPr4+=tetrapropylammonium cation, has been synthesized. 1 revealed a thermally induced valence tautomeric transition at T1/2=236 K (cooling)/237 K (heating) between Fem+ (m=2 or 3) and Cl2Ann− (n=2 or 3) that induced valence modulations between [FeIIHSFeIIIHS(Cl2An2−)2(Cl2An.3−)]2− at T>T1/2 and [FeIIIHSFeIIIHS(Cl2An2−)(Cl2An.3−)2]2− at T<T1/2. Even in a two‐dimensional network structure, the low‐temperature phase [FeIIIHSFeIIIHS(Cl2An2−)(Cl2An.3−)2]2− valence set can be regarded as a magnetic chain‐knit network, where ferrimagnetic Δ and Λ chains of [FeIIIHS(Cl2An.3−)]∞ are alternately linked by the diamagnetic Cl2An2−. This results in a slow magnetization behavior attributed to the structure acting as a single‐chain magnet at lower temperatures.

Coupling Dielectric Functionality with Magnetic Properties in Coordination Metal Complexes

“…External‐stimuli‐responsive inter‐ or intramolecular electron transfer can trigger electronic state configuration and magnetic state changes [55–64] . One electron is exchanged between a donor (D) and acceptor (A), resulting in two valence isomers, namely, neutral DA and ionic D + A − , which can be controlled by modulating the difference in the redox potential of the D/A units [65–67] …”

Heteroleptic LaIII Anilate/Dicarboxylate Based Neutral 3D-Coordination Polymers

“…Metal−organic frameworks (MOFs) and coordination polymers (CPs) are an emerging class of microporous solids, which have been intensively studied during the last two decades due to their structural and functional diversity. They have potential applications as gas adsorbents [ 1 , 2 , 3 ]; luminescent [ 4 , 5 , 6 , 7 ]; electrochemical or photophysical sensors [ 8 , 9 ]; and catalytic [ 10 , 11 , 12 ], optical [ 13 ], electrically conductive [ 14 ], and magnetic materials [ 15 , 16 , 17 , 18 ]. The physical and chemical properties, crystalline structure and topologies of coordination polymers depend on the properties of the organic ligands and/or the metal ions.…”

“…The introduction of different substituents in the 3 and 6 positions of the quinoid ring allows for a wide range of variations in their electronic and steric properties. Most commonly, researchers use chlorine [ 16 , 19 , 20 ], bromine [ 17 , 21 , 22 ], fluorine [ 23 , 24 ], nitro [ 25 , 26 ] and cyano-substituted [ 22 , 27 , 28 ] anilate ligands. The first paper on the use of 3,6-di-tert-butyl-2,5-dihydroxy-para-benzoquinone in the construction of 2D layered lanthanum MOFs was published [ 29 ].…”

A supramolecular helicate with two independent Fe(ii) switchable centres and a [Fe(anilate)3]3− guest

“…In this respect, complexes of the type [M(ani) 3 ] nÀ (M = various metals; ani = anilate derivatives) are an appealing choice as guest, since they are part of a prolific source of unique properties linked to electron transfer phenomena. [22][23][24][25] The presence of [Fe(anilate) 3 ] 3À in a solution of Fe(BF 4 ) 2 and L2 (Fig. 1) in dry methanol under inert atmosphere, generates crystals after two weeks, of the host-guest supramolecular assembly [Fe(anilate) 3 ]@[Fe 2 (L2) 3 ](BF 4 ) (1).…”

“…In this respect, complexes of the type [M(ani) 3 ] n− (M = various metals; ani = anilate derivatives) are an appealing choice as guest, since they are part of a prolific source of unique properties linked to electron transfer phenomena. 22–25…”