Heterometallic Aluminum–Chromium Phenazine and Thiophenazine Complexes. Formation of a Tetranuclear Chromium(I) Sandwich Complex

Abstract

Treatment of a suspension of phenazine and CrCl2(THF)2 in toluene with 4 equiv of triethylaluminum (Scheme ) affords the pentanuclear, heterobimetallic, and divalent [AlEt2(THF)(μ3-η1:η1-C12H8N2)(μ-κ1-AlEt2Cl)]2(μ-Cr) (1). In this species the two nitrogen atoms of each phenazine ligand are connected to three metals. A similar reaction with thiophenazine afforded trimetallic [(η1:η1-C12H8NS)(μ-κ1-AlEt2Cl)]2(μ-Cr) (2), where the sulfur atoms remained uncoordinated. When the preparation of 1 was carried out in the presence of excess Et3Al, the reaction took a different pathway, affording [AlEt2]2(μ-η1:η1-η6:η6-C12H8N2Cr)2 (3). The aluminate residues hold two parallel and eclipsed phenazine molecules, forming a rigid cage where the two chromium atoms are encapsulated. The ambiguity about the metal oxidation state has been solved by DFT calculations, revealing the formal oxidation state of chromium as being better described as monovalent.

Rechargeable Aqueous Aluminum Organic Batteries

“…[26] The most possible and stable structure of reduced product is shown in Figure S20, the complex features two PZ rings that are parallel to each other, and Al(OTF) 2+ residues each bridge a pair of nitrogen atoms from the two ligands in an overall cage structure. [27] These results consistent with the aforementioned analyses of optical and photoelectron spectra. Based on the…”

Rechargeable Aqueous Aluminum Organic Batteries

“…According to the results of molecular electrostatic potential (MESP) mapping of PZ, the blue regions around the PZ nitrogen atoms have more negative MESP values, representing highly nucleophilic reactive reaction sites which are attractive for the uptake of carrier ions [26] . The most possible and stable structure of reduced product is shown in Figure S20, the complex features two PZ rings that are parallel to each other, and Al(OTF) 2+ residues each bridge a pair of nitrogen atoms from the two ligands in an overall cage structure [27] . These results consistent with the aforementioned analyses of optical and photoelectron spectra.…”