Mixed Valence Mn(II)/Mn(III) [3 × 3] Grid Complexes: Structural, Electrochemical, Spectroscopic, and Magnetic Properties
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- 作者：Laurence K. Thompson ; Timothy L. Kelly ; Louise N. Dawe ; Hilde Grove ; Martin T. Lemaire ; Judith A. K. Howard ; Elinor C. Spencer ; Craig J. Matthews ; Stuart T. Onions ; Simon J. Coles ; Peter N. Horton ; Mi
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：November 29, 2004
- 年：2004
- 卷：43
- 期：24
- 页码：7605 - 7616
- 全文大小：309K
- 年卷期：v.43,no.24(November 29, 2004)
- ISSN：1520-510X
文摘
Mn(II)9 grid complexes with a [Mn9(
-O)12] core, obtained by self-assembly of a series of tritopic picolinic dihydrazoneligands with Mn(II) salts, have been oxidized by both chemical and electrochemical methods to produce mixedoxidation state systems. Examples involving [Mn(III)3Mn(II)6] and [Mn(III)4Mn(II)5] combinations have been produced.Structures are reported for [Mn9(2poap-2H)6](NO3)6·14H2O (1), [Mn9(2poap-2H)6](ClO4)10·10H2O (3), and [Mn9(Cl2poap-2H)6](ClO4)9·14H2O·3CH3CN (10). Structural studies show distinct contraction of the corner grid sites onoxidation, with overall magnetic properties consistent with the resulting changes in electron distribution.Antiferromagnetic exchange in the outer ring of eight metal centers creates a ferrimagnetic subunit, which undergoesantiferromagnetic coupling to the central metal, leading to S = 1/2 (3) and S = 2/2 (10) ground states. Two moderatelyintense absorptions are observed on oxidation of the Mn(II) grids in the visible and near-infrared (1000 nm, 700nm), associated with charge transfer transitions (LMCT, IVCT respectively). Compound 1 crystallized in the monoclinicsystem, space group P21/n, with a = 21.308(2) Å, b = 23.611(2) Å, c = 32.178(3) Å, 
= 93.820(2)
. Compound3 crystallized in the tetragonal system, space group I
, with a = b = 18.44410(10) Å, c = 24.9935(3) Å. Compound10 crystallized in the triclinic system, space group P
, with a = 19.1150(10) Å, b = 19.7221(10) Å, c = 26.8334(14) Å, 
= 74.7190(10), = 77.6970(10), 
= 64.7770(10). The facile oxidation of the Mn(II)9 grids ishighlighted in terms of their potential use as molecular based platforms for switching and data storage.
-O)12] core, obtained by self-assembly of a series of tritopic picolinic dihydrazoneligands with Mn(II) salts, have been oxidized by both chemical and electrochemical methods to produce mixedoxidation state systems. Examples involving [Mn(III)3Mn(II)6] and [Mn(III)4Mn(II)5] combinations have been produced.Structures are reported for [Mn9(2poap-2H)6](NO3)6·14H2O (1), [Mn9(2poap-2H)6](ClO4)10·10H2O (3), and [Mn9(Cl2poap-2H)6](ClO4)9·14H2O·3CH3CN (10). Structural studies show distinct contraction of the corner grid sites onoxidation, with overall magnetic properties consistent with the resulting changes in electron distribution.Antiferromagnetic exchange in the outer ring of eight metal centers creates a ferrimagnetic subunit, which undergoesantiferromagnetic coupling to the central metal, leading to S = 1/2 (3) and S = 2/2 (10) ground states. Two moderatelyintense absorptions are observed on oxidation of the Mn(II) grids in the visible and near-infrared (1000 nm, 700nm), associated with charge transfer transitions (LMCT, IVCT respectively). Compound 1 crystallized in the monoclinicsystem, space group P21/n, with a = 21.308(2) Å, b = 23.611(2) Å, c = 32.178(3) Å, = 93.820(2). Compound3 crystallized in the tetragonal system, space group I, with a = b = 18.44410(10) Å, c = 24.9935(3) Å. Compound10 crystallized in the triclinic system, space group P, with a = 19.1150(10) Å, b = 19.7221(10) Å, c = 26.8334(14) Å, = 74.7190(10), = 77.6970(10), = 64.7770(10). The facile oxidation of the Mn(II)9 grids ishighlighted in terms of their potential use as molecular based platforms for switching and data storage.