An Unprecedented Mixed-Charged State in a Supramolecular Assembly of Ligand-Based Mixed-Valence Redox Isomers (ET.+)3[CrIII(Cl4SQ)2(Cl4Cat)]−[CrIII(Cl4SQ)(Cl4Cat)2]2−

Abstract

Coexistence of two kinds of ligand‐based mixed‐valence (LBMV) isomers is observed for the first time in the title compound (see scheme). Together with its mixed‐charged state, the compound shows semiconducting behavior with an intermolecular ferromagnetic interaction, which is attributable to the association of five paramagnetic components in the crystal phase.

Synthesis and Ligand-Based Mixed Valency ofcis-andtrans-CrIII(X4SQ)(X4Cat)(L)n(X = Cl and Br,n= 1 or 2) Complexes: Effects of Solvent Media on Intramolecular Charge Distribution and Ligand Dissociation of CrIII(X4SQ)3

“…Each spectrum is depicted by two characteristic absorption bands observed near 1450 cm -1 and a broad, strong band near 1100 cm -1 . Similar spectra have been observed for [Cr III (X 4 SQ) 3 - n (X 4 Cat) n ] n - ( n = 1−2) redox isomers with three o -quinonate ligands in the LBMV state. 6a,b By comparing the spectra, the bands at 1450 and 1100 cm -1 are assigned to the vibration modes characteristic for SQ •- and Cat 2- , respectively. The data clearly demonstrates the LBMV state of 1 − 6 , although complexes 1 and 5 possess crystallographic ambiguity for distinction of the SQ and Cat ligands due to their crystallographic symmetry.…”

“…The acetonitrile ligands in 1 coordinate to the chromium ion in a trans fashion, allowing two o -quinone ligands to sit coplanarly. The Cr−O bond distances are found to be 1.929(3) and 1.935(3) Å for Cr(1)−O(1) and Cr(1)−O(2) bonds, respectively, and the average distance, 1.932(3) Å, is similar to those of the series of [Cr III (X 4 SQ) 3 - n (X 4 Cat) n ] n - isomers, 6a,b indicating the trivalent nature of the chromium atom. As a complex of Cr(III), a formal combination of a X 4 SQ and X 4 Cat can be suggested for charge distribution on the quinone ligands.…”

“…All chemicals were reagent grade. 3,4,7,8-Tetramethyl-1,10-phenanthroline was purchased from Aldrich and 2,2‘-bipyridine from Tokyo Kasei Co., Ltd. Complexes Cr III (X 4 SQ) 3 ·4C 6 H 6 were synthesized by the procedure described in the literature 6a. All of the reagents and solvents were used without special purification.…”

“…Chromium(III) complexes, Cr III (X 4 SQ) 3 (X = Cl and Br), demonstrate good examples of the stepwise chemical oxidation/reduction processes occurring on the ligand moieties as shown in eq 3. Among these seven-membered redox isomers, ligand-based mixed-valence (LBMV) redox isomers, [Cr III (X 4 SQ) 3 - n (X 4 Cat) n ] n - ( n = 1−2), have been isolated by stepwise one- and two-electron reduction …”

Ligand-Induced Tuning of the Oxidase Activity of μ-Hydroxidodimanganese(III) Complexes Using 3,5-Di-tert-butylcatechol as the Substrate: Isolation and Characterization of Products Involving an Oxidized Dioxolene Moiety

“…The observed C–O distances are usually short (ca. 1.28 Å) , when the ligand is in the quinone or semiquinone state compared to a fully reduced catecholate ligand (ca. 1.34 Å) .…”