title: A family of [Mn6] complexes featuring tripodal ligands.
abstract: The synthesis and magnetic properties of four new Mn complexes containing tripodal alcohol ligands are reported: [Mn6(OAc)6(H2tea)2(tmp)2].2MeCN (1.2MeCN), [Mn6(acac)4(OAc)2(Htmp)2(H2N-ep)2] (2), [Mn6(OAc)8(tmp)2(py)4].2py (3.2py), and [Mn6(OAc)8(thme)2(py)4].2py (4.2py) [H3tea, triethanolamine; H3tmp, 1,1,1-tris(hydroxymethyl)propane; H2N-H2ep, 2-amino-2-ethyl-1,3-propanediol; H3thme, 1,1,1-tris(hydroxymethyl)ethane]. All complexes are mixed-valent with a [Mn(III)2Mn(II)4] oxidation assignment and are constructed from four edge-sharing triangles but differ slightly in that complexes 1 and 2 display a [Mn(III)2Mn(II)4(mu2-OR)6(mu3-OR)4]4+ core, while complexes 3 and 4 feature [Mn(III)2Mn(II)4(mu2-OR)2(mu3-OR)4]8+ and [Mn(III)2Mn(II)4(mu2-OR)4(mu3-OR)4]6+ cores, respectively. dc and ac magnetic susceptibility studies in the 2-300 K range for complexes 1-4 reveal the presence of dominant antiferromagnetic exchange interactions, leading to ground states of S = 0 for 1 and 2, while complexes 3 and 4 display S = 4 ground states with D = -0.44 and -0.58 cm(-1), respectively. Single-molecule magnetism behavior was confirmed for 3 and 4 by the presence of sweep-rate and temperature-dependent hysteresis loops in single-crystal M vs H studies at temperatures down to 40 mK. Theoretical density functional calculations were used to evaluate the individual pairwise exchange interactions present, confirming the diamagnetic ground states for 1 and 2 and the S = 4 ground states for 3 and 4.
authors.affiliation: School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K.
authors.forename: Constantinos J
authors.initials: CJ
authors.lastname: Milios
authors.forename: Maria
authors.initials: M
authors.lastname: Manoli
authors.forename: Gopalan
authors.initials: G
authors.lastname: Rajaraman
authors.forename: Abhudaya
authors.initials: A
authors.lastname: Mishra
authors.forename: Laura E
authors.initials: LE
authors.lastname: Budd
authors.forename: Fraser
authors.initials: F
authors.lastname: White
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wernsdorfer
authors.forename: George
authors.initials: G
authors.lastname: Christou
authors.forename: Euan K
authors.initials: EK
authors.lastname: Brechin