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Inventing the double wheel: A mixed-valent [Mn32] cluster with a very rare "double-decker" wheel topology (see its metal-oxygen core: MnIII blue, MnII pink, O red) is reported. It is by far the highest-nuclearity example of its type, and it displays SMM behavior with the largest effective barrier to magnetization relaxation (Ueff≈ 44.5 K) for any molecular wheel. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 50 19 4441 4444 Cited By :74

The combined use of the anion of methyl 2-pyridyl ketone oxime (mpko -) and azides (N3-) in non-carboxylate Mn chemistry has afforded two new Mn6 clusters, [Mn6O 3(N3)3(mpko)6(H2O) 3](ClO4J2 (1) and [Mn6O3(N3) 5(mpko)6(H2O)] (2), which are mixed-valence (MnII, 5 MnIII). The 1:1:1:1 reaction of Mn(C1O 4)2·6H2O, mpkoH, NaN3 and NEt3 in MeOH gave the cationic complex 1, while a similar reaction using additional NaO2CMe led instead to the neutral complex 2. The structurally unprecedented cores of the two cages are very similar, and contain the six Mn ions in a topology comprising three vertex-sharing oxide-centered triangles bridged by two end-on azides. Variable-temperature, solidstate dc and ac magnetization studies were carried out for 1 and 2 in the 1.8-300 K range. The data reveal S = 5/2 ground states for both complexes, and fitting of magnetization vs. field (H) and temperature (T) data by matrix diagonalization for 1 gave S = 5/2, D = -1.4(3) cm-1, and g = 1.99(1), where D is the axial zero-field splitting (ZFS) parameter. The combined results demonstrate the versatility of 2-pyridyl ketone oxime anions in the presence of suitable ancillary ligands, such as azides, for the synthesis of new Mn clusters, without requiring the co-presence of carboxylate ligands. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. 15 2244 2253 Cited By :11

Palladium(II) acetate in non-deaerated chloroform splits Bunsen's cacodyl disulfide, Me2As(S)-S-AsMe2, giving the complex (Me 2AsS2J2Pd, slightly soluble in chloroform, and the arsonium ion Me2As:+. However, after a few minutes the complex reacted giving Me2As(S)-O-As(S)Me2 and other, so far unidentified compounds. Therefore, the complex (Me2AsS 2J2Pd was prepared from sodium dimethyldithioarsinate dihydrate, Me2AsS2Na-2H2O, and palladium(II) acetate. (Me2AsS2)2Pd reacts with Pd 11 and Ph3P in a different way compared to other (Me 2AsS2)xM (M = heavy metal cation) and (Me 2PS2J2Pd. The reaction of equimolar quantities of Me2AsS2Na-2H2O and Ph3P under argon involved four consecutive reactions with Me2As-O-AsMe 2 and Me2AsS2Na as the final products. The salt Me2AsS2Na-2H2O has been structurally characterized: triclinic, P1, a = 6.0285(2) A, b = 6.5552(2) Å, c = 12.1480(4) Å, a = 98.282(2)°, β = 93.994(3)°, y = 115.951(3)°, V= 422.38(3) Å3, Z = 2, R1= 0.0207, wR2 = 0.0414. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA. 635 13-14 2203 2209 Cited By :8

The initial use of 2-pyridyl-substituted oximes [(py)C(R)-NOH R = Me, Ph]/sulfate blend in nickel(II) chemistry has yielded a family of hexanuclear clusters. The syntheses, structures and magnetic properties are reported of [Ni6(SO4)4-(OH){(py)C(Me)NO} 3{(py)C(Me)NOH}3(MeOH)2(H2O)] (1), [Ni6(SO4)4(OH){(py)C(ph)NO}3{(py) C(ph)NOH}3(MeOH)3] (2) and [Ni6(SO 4)4(OH){(py)C(ph)NO}3{(py)C(ph)NOH} 3(H2O)3] (3), where (py)C(Me)NOH is methyl 2-pyridyl ketone oxime and (py)C(ph)NOH is phenyl 2-pyridyl ketone oxime. The hexanuclear molecules present in the three complexes have similar structures which contain the [Ni6(μ3-OH)(μ3-SO 4)3(μ3-ONR)3]2+ core. The core consists of six NiII ions arranged as two parallel equilateral triangular subunits, one small (Ni⋯Ni ca. 3.3 Å) and the other larger (Ni⋯Ni ca. 6.0 Å). Characteristic IR bands are discussed in terms of the known structures of 1-3. The magnetic properties of 1 and 2 have been studied by variable-temperature dc magnetic susceptibility techniques which indicate antiferromagnetic interactions. A simple 2-J model was found to be adequate to describe the similar thermal variation of the molar magnetic susceptibilities of 1 and 2. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007. 18 2761 2774 Cited By :50

(Figure Presented) Singles networks: The use of 1,3-propanediol and of 2-methyl-1,3-propanediol in manganese carboxylate chemistry leads to two new 3D coordination polymers with an unprecedented Mn19 repeating unit. The polymers have open framework structures with nanometer-sized cavities (see picture Na not visible, Mn blue, O red, C gray). The Mn19 units have a ground spin state of S = 23/2 and behave as single-molecule magnets. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA. 45 46 7722 7725 Cited By :114

Axes of power: Jahn-Teller isomerism (that is, Jahn-Teller distortion along different axes) accounts for the presence of both faster and slower relaxing magnetization dynamics of the title compound (see core structure blue Mn, red O, gray C), which is a single-molecule magnet (SMM). The new compound is a structural variant of the [Mn12] family of SMMs and is prepared by a reductive aggregation of [MnO4]- in a mixture of MeOH/PhCO2H. (Figure presented). 43 46 6338 6342 Cited By :52

The syntheses of the first mixed-metal CeIVMnIV complexes are reported. [CeMn2O3(O2CMe)(NO3)4(H2O)2(bpy)2](NO3) (1; bpy = 2,2‘-bipyridine) was obtained from the reaction of Mn(NO3)2·xH2O and bpy with (NH4)2Ce(NO3)6 in a 1:1:2 molar ratio in 25% aqueous acetic acid. The complexes [CeMn6O9(O2CR)9(X)(H2O)2]y+ (R = Me, X = NO3-, y = 0 (2); R = Me, X = MeOH, y = +1 (3); R = Et, X = NO3-, y = 0 (7)) were obtained from reactions involving a [Mn(O2CR)2]·4H2O/CeIV ratio of ∼1:1.5 in concentrated aqueous carboxylic acid. A related reaction in less-concentrated aqueous acetic acid and in the presence of L (where L = 2-hydroxy-6-methylpyridine (mhpH), 2-pyrrolidinone (pyroH), or pyridine (py)) gave [Ce3Mn2O6(O2CMe)6(NO3)2(L)a(H2O)b] (L = mhpH, a = 4, b = 0 (4); L = pyroH, a = 2, b = 3 (5)) and {{(pyH)3[Ce3Mn2O6(O2CMe)7.5(NO3)3]·(HO2CMe)0.5·(H2O)2}2(NO3)}n (6), respectively. Solid-state magnetic susceptibility (χM) data for compounds 1, 4, and 5 were fit to the theoretical χMT versus T expression for a MnIV2 complex d...

Reaction of [V(VI)OCl(2)(thf)(2)] with a bidentate nitrogen-donor ligand (L: phen=1,10-phenanthroline, 5-mephen=5-methyl-1,10-phenanthroline, bipy=2,2'-bipyridine, 5,5'-me(2)bipy=5,5'-dimethyl-2,2'-bipy) in methyl alcohol, in the presence of triethylamine, leads to the formation of hexameric [V(2) (IV)V(4) (V)] oxo-alkoxo-vanadates of the general formula [V(6)O(12)(mu(2)-OCH(3))(4)(L)(4)].x H(2)O [L=phen (1.4 H(2)O), 5-mephen (2.6 H(2)O), bipy (3.4 H(2)O), 5,5'-me(2)bipy (4.H(2)O)]. X-ray structure analysis of 1.2 H(2)O and 4.8 CH(3)OH revealed a pair of V(3)O(13)N(4) trimeric units sharing two corners, with a centrosymmetric planar V(6)-core. In addition, a fully oxidized V(V) species [V(V) (4)O(8)(OCH(3))(2)(mu(3)-OCH(3))(2)(5,5'-me(2)bipy)(2)].3 CH(3)OH (5.3 CH(3)OH) was isolated from the reaction mixture used for the synthesis of 4.H(2)O. The crystal structure of 5.3 CH(3)OH revealed a dicubane-like framework with two missing vertices. Electron paramagnetic resonance (EPR) and variable temperature magnetic susceptibility studies for the hexamers 1.4 H(2)O and 3.4 H(2)O showed the complete localization of the single 3d electrons on the V(IV) ions and unusual ferromagnetic interaction between the two paramagnetic vanadium(IV) ions separated by a distance of about 5.1 A. Furthermore, intermolecular antiferromagnetic interactions through pi-contacts of phenyl rings were observed for these species below 8 K. The ferromagnetic exchange coupling observed in the hexanuclear compounds 1.4 H(2)O and 3.4 H(2)O is also discussed using ab initio UHF calculations on a model compound. The value of the exchange coupling constant (3.7 cm(-1)) for this model compound, calculated using the broken symmetry approach, is in good agreement, both in sign and magnitude, with the experimental J values (6.00 cm(-1) for 1.4 H(2)O and 8.54 cm(-1) for 3.4 H(2)O).