264216-65-1Relevant articles and documents
Synthesis, crystal structure, and high-precision high-frequency and -field electron paramagnetic resonance investigation of a manganese(III) complex: [Mn(dbm)2(py)2](ClO4)
Aromi, Guillem,Telser, Joshua,Ozarowski, Andrew,Brunel, Louis-Claude,Stoeckli-Evans, Helen-Margaret,Krzystek
, p. 187 - 196 (2005)
The complex [Mn(dbm)2(py)2](ClO4) (dbm = anion of 1,3-diphenyl-1,3-propanedione (dibenzoylmethane), py = pyridine) was synthesized and characterized by X-ray crystallography. It has tetragonally distorted geometry with the axial positions occupied by the py ligands and the equatorial positions by the dbm ligands. This mononuclear complex of high-spin Mn(III) (3d4, S = 2) was studied by high-frequency and -field electron paramagnetic resonance (HFEPR) both as a solid powder and in frozen dichloromethane solution. Very high quality HFEPR spectra were recorded over a wide range of frequencies. The complete dataset of resonant magnetic fields versus transition energies was analyzed using automated fitting software. This analysis yielded the following spin Hamiltonian parameters (energies in cm -1): D = -4.504(2), E = -0.425(1), B40 = -1.8(4) × 10-4, B42 = 7(3) × 10-4, B44 = 48(4) × 10-4, gx = 1.993(1), gy = 1.994(1), and gz = 1.983(1), where the B4n values represent fourth-order zero-field splitting terms that are generally very difficult to extract, even from single-crystal measurements. The results here demonstrate the applicability of HFEPR at high-precision measurements, even for powder samples. The zero-field splitting parameters determined here for [Mn(dbm)2(py) 2]+ are placed into the context of those determined for other mononuclear complexes of Mn(III).
Slow magnetic relaxation in mononuclear octahedral manganese(III) complexes with dibenzoylmethanide ligands
Chen, Lei,Wang, Jing,Liu, Yuan-Zhong,Song, You,Chen, Xue-Tai,Zhang, Yi-Quan,Xue, Zi-Ling
, p. 271 - 278 (2015)
The structural characterization and magnetic studies of three mononuclear MnIII complexes based on the dibenzoylmethanido (dbm-) ligand, Mn(dbm)3 (1) and [Mn(dbm)2(L)2](ClO4) (L = dimethyl
Tetranuclear manganese carboxylate complexes with a trigonal pyramidal metal topology via controlled potential electrolysis
Wang, Sheyi,Wemple, Michael S.,Yoo, Jae,Folting, Kirsten,Huffman, John C.,Hagen, Karl S.,Hendrickson, David N.,Christou, George
, p. 1501 - 1513 (2000)
Controlled potential electrolysis (CPE) procedures are described that provide access to complexes with a [Mn4(μ3-O)3(μ3-O2CR)]6+ core (3Mn(III),Mn(IV)) and a trigonal pyramidal metal topology, starting from species containing the [Mn4(μ3-O)2]8+ core (4Mn(III)). [Mn4O2(O2CMe)6(py)2(dbm)2] (6): triclinic, P1, a = 10.868(3) A, b = 13.864(3) A, c = 10.625(3) A, α = 108.62(1)°, β = 118.98(1)°, γ = 89.34(2)°, V = 1307 A3, Z = 1, T = -131 °C, R (R(w)) = 3.24 (3.70)%. [Mn4O2(O2CPh)6(py)(dbm)2] (8): monoclinic, P21/c, a = 14.743(6) A, b = 15.536(8) A, c = 30.006(13) A, β = 102.79(1)°, V = 6702 A3, Z = 4, T = -155 °C, R (R(w)) = 4.32 (4.44)%. Both 6 and 8 contain a [Mn4O2]8+ core; 8 only has one py group, the fourth Mn(III) site being five-coordinate. (NBu(n)4)[Mn4O2(O2CPh)7(dbm)2] (10) is available from two related procedures. CPE of 10 at 0.65 V vs ferrocene in MeCN leads to precipitation of [Mn4O3(O2CPh)4(dbm)3] (11); similarly, CPE of 6 at 0.84 V in MeCN/CH2Cl2 (3:1 v/v) gives [Mn4O3(O2CMe)4(dbm)3] (12). Complex 11: monoclinic, P21/n, a = 15.161(3) A, b = 21.577(4) A, c = 22.683(5) A, β = 108.04(3)°, V = 7056 A3, Z = 4, T = -100 °C, R (wR2) = 8.63 (21.80)%. Complex 12: monoclinic, P21/n, a = 13.549(2) A, b = 22.338(4) A, c = 16.618(2) A, β = 103.74(1)°, V = 4885 A3, Z = 4, T = -171 °C, R (R(w)) = 4.63 (4.45)%. Both 11 and 12 contain a [Mn4(μ3-O)3(μ-O2CR)] core with a Mn4 trigonal pyramid (Mn(IV) at the apex) and the RCO2- bridging the Mn(III)3 base. However, in 11, the carboxylate is η2,μ3 with one O atom terminal to one Mn(III) and the other O atom bridging the other two Mn(III) ions, whereas in 12 the carboxylate is η1,μ3, a single O atom bridging three Mn(III) ions. Variable-temperature, solid-state magnetic susceptibility studies on 11 and 12 show that, for both complexes, there are antiferromagnetic exchange interactions between Mn(III)/Mn(IV) pairs, and ferromagnetic interactions between Mn(III)/Mn(III) pairs. In both cases, the resultant ground state of the complex is S = 9/2, confirmed by magnetization vs field studies in the 2.00-30.0 K and 0.50-50 kG temperature and field ranges, respectively.
