title: 1,1,1-Tris(hydroxymethyl)propane in manganese carboxylate chemistry: synthesis, structure and magnetic properties of a mixed-valence [MnIII4MnII4] cluster featuring the novel [MnIII4MnII4(mu3-OR)6(mu2-OR)8]6+ core.
abstract: The reaction between MnBr(2).4H(2)O with H(3)tmp (1,1,1-tris(hydroxymethyl)propane) in MeCN in the presence of Na(O(2)CCMe(3)) and NBu(4)Br produces the complex [Mn(8)(O(2)CCMe(3))(2)(tmp)(2)(Htmp)(4)Br(4)(H(2)O)(2)].2MeCN (1.2MeCN) in good yield. The centrosymmetric octanuclear molecule consists of four Mn(III) and four Mn(II) ions assembled together by fourteen alkoxo bridges to give a [Mn(III)(4)Mn(II)(4)(mu(3)-OR)(6)(mu(2)-OR)(8)](6+) rod-like core in which the metal centres are arranged in a planar zigzag fashion. Peripheral ligation is provided by a combination of bridging pivalate ions, terminal bromides and water molecules. Dc magnetic susceptibility measurements reveal the presence of dominant antiferromagnetic interactions leading to a spin ground state of S = 0. A rationalization of this result is attempted by structural comparison with previously reported tetranuclear manganese complexes containing the [Mn(III)(2)Mn(II)(2)(mu(3)-OR)(2)(mu(2)-OR)(4)] core in which the magnetic interactions are ferromagnetic.
authors.affiliation: School of Chemistry, The University of Edinburgh, UK.
authors.forename: Constantinos J
authors.initials: CJ
authors.lastname: Milios
authors.forename: Francesca P A
authors.initials: FP
authors.lastname: Fabbiani
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Muralee
authors.initials: M
authors.lastname: Murugesu
authors.forename: George
authors.initials: G
authors.lastname: Christou
authors.forename: Euan K
authors.initials: EK
authors.lastname: Brechin
mesh_terms: D001965:Bromides / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D004574:Electromagnetic Fields; D007501:Iron / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D017895:Manganese Compounds / Q000138:chemical synthesis*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010421:Pentanoic Acids / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D001965:Bromides; D002264:Carboxylic Acids; D017895:Manganese Compounds; D009942:Organometallic Compounds; D010421:Pentanoic Acids; D011409:Propylene Glycols; D014867:Water; C018163:trimethylolpropane; C005566:pivalic acid; D007501:Iron