New Molecular Assemblies of Redox Isomers, [CrIII(X4SQ)3-n(X4Cat)n]-<
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- 作者：Ho-Chol Chang ; Hitoshi Miyasaka ; and Susumu Kitagawa
- 刊名：Inorganic Chemistry
- 出版年：2001
- 出版时间：January 1, 2001
- 年：2001
- 卷：40
- 期：1
- 页码：146 - 156
- 全文大小：219K
- 年卷期：v.40,no.1(January 1, 2001)
- ISSN：1520-510X
文摘
A series of redox isomers of [CrIII(X4SQ)(X4Cat)2]2-, [CrIII(X4SQ)2(X4Cat)]-, and [CrIII(X4SQ)3]0 (X = Cl andBr, SQ = semiquinonate, and Cat = catecholate) have been synthesized and characterized as charge-transfer(CT) compounds with metallocenium cations: (CoIIICp2)2[CrIII(Cl4SQ)(Cl4Cat)2] (1), (CoIIICp2)2[CrIII(Br4SQ)(Br4Cat)2] (2), (FeIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)]·C6H6 (4), (FeIIICp2)[CrIII(Br4SQ)2(Br4Cat)]·CS2 (5), and(FeIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)][CrIII(Cl4SQ)3] (6). First, the oxidation states of the chromium complexes arestrongly dependent on the redox potentials of the metallocenes used. The CoIICp2, exhibiting stronger reductionpower than FeIICp2, is useful for two-electron reduction of the [CrIII(X4SQ)3]0, affording [CrIII(X4SQ)(X4Cat)2]2-(1 and 2), which are first isolated and crystallographically characterized in the solid state. In contrast the reactionwith FeIICp2 affords only [CrIII(X4SQ)2(X4Cat)]- (4 and 5). Second, solvents influence crystal structures of thesecompounds. The solvent set of C6H6/CS2 gives 1:1:C6H6 compound 4 with unique charged anions,[CrIII(Cl4SQ)2(Cl4Cat)]-, while the other set, n-C6H12/CS2, affords 1:2 compound 6 including the two redox isomers,[CrIII(Cl4SQ)2(Cl4Cat)]- and [CrIII(Cl4SQ)3]0. The [CrIII(X4SQ)(X4Cat)2]2- anions in 1 and 2 show no significantinterconnection between them (discrete type), while the [CrIII(X4SQ)2(X4Cat)]- anions in 4-6 show one-dimensionalcolumn-type structures with the aid of intermolecular stacking interactions of the ligand moieties. The anions in4 show additional stacking interaction with the [FeIIICp2]+ to form one-dimensional ···[D][A][S][D][A]··· (D =[FeIIICp2]+, A = [CrIII(Cl4SQ)2(Cl4Cat)]-, and S = C6H6) type mixed-stack arrangements similar to that ofpreviously reported (CoIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)]·C6H6 (3). Compound 6 forms a two-dimensional sheet structurewhere the two redox isomers, [CrIII(Cl4SQ)2(Cl4Cat)]- and [CrIII(Cl4SQ)3]0, are included. The sheet is regardedas a mixed-valence molecular assembly. Two types of the anions, [CrIII(X4SQ)(X4Cat)2]2- (1 and 2) and[CrIII(X4SQ)2(X4Cat)]- (4-6), exhibiting an intramolecular mixed-valence state, show intramolecular intervalenceCT transition (IVCT) from the Cat to the SQ at near 5800 and 4300 cm-1, respectively, both in the solution andin the solid states. The intermolecular mixed-valence state of 6 was characterized by absorption spectroscopy,electric conductivity, and SQUID magnetometry. Interestingly, this mixed-valence state of the chromium moduleis dependent on the redox active nature of the coordinated ligands.