Yongge Wei

Polyoxometalate chain-like polymer: the synthesis and crystal structure of a 1D compound, [Mo36O108(NO)4(MoO)2La2(H2O)28]n·56nH2O

Abstract Reaction of {Mo 36 (NO) 4 } with LaCl 3 in the presence of NH 2 OH·HCl results in the formation of a novel chain-like polymer, [Mo 36 O 108 (NO) 4 (MoO) 2 La 2 (H 2 O) 28 ] n ·56 n H 2 O, in which the {Mo 36 (NO) 4 } units are linked to each other by two parallel La atoms.

Synthesis and crystal structure of the heteropolyvanadate anion [AsV12P40(VO)2]9−

The structure of (Et 4 N) 3 H 6 [AsV 12 O 40 (VO) 2 ]·20H 2 O has been determined by single-crystal X-ray diffraction analysis. In the anion the central AsO 4 tetrahedron and 12VO 6 octahedra form the usual Keggin structure (α-isomer) and the remaining two VO 3+ groups occupy the cavities in the Keggin structure, where a two-fold axis passes to form trans -located tetragonal pyramidal caps.

SYNTHESIS, STRUCTURE AND MAGNETIC PROPERTIES OF A POLYMERIC TRINUCLEAR MIXED-VALENCE MANGANESE MALONATE COMPLEX

Abstract A mixed-valence Mn III , Mn II , Mn III malonate polymeric cluster having a trimeric repeat unit, {[Mn II (H 2 O) 4 ] [Mn(malonate) 2 (H 2 O)] 2 } n , which is the first example of mixed-valence manganese carboxylate polymeric complex, has been prepared and characterized structurally. This complex behaves as an antiferromagnet and has a Neel temperature of ca 10 K.

Crystal structure and metamagnetic property of a 2-D layered complex, [FeII(N3)2(pyz)]n (pyz = pyrazine)

In crystals of n[FeII(N3)2(pyz)]n n (pyz = pyrazine), two adjacent Fe2+ ions nare bridged via two μ-1,1-N3− nligands along the c axis to afford ferromagnetically coupled nlinear chains, which are bridged via nμ-pyrazine ligands along nthe b axis to afford 2-D antiferromagnetically coupled layers; nthese competitive magnetic couplings lead to the occurrence of metamagnetic nbehavior.

Synthesis, crystal structure and magnetic property of a binuclear iron(III) citrate complex

The compound (Hql)2[Fe2(cit)2(H2O)2]·4H2O (1) [ql = quinoline, cit4− = C(O−)(CO−2)(CH2CO−2)2], prepared by reacting ferric nitrate, sodium citrate and quinoline in a molar ratio of 1:1:1 in aqueous solution, was characterized by density measurements, elementary analysis, i.r., X-ray crystallography and magnetic measurements. The X-ray crystallography results reveal that the molecule (1) consists of a binuclear iron(III) citrate anionic complex [Fe2(cit)2(H2O)2]2− and two protonated quinolines [Hql]+. The anionic complex has a centro-symmetric structure, in which two Fe3+ ions are bridged by two μ2-alkoxo groups of the two deprotonated citrate ligands. The other coordination sites of the two slightly distorted octahedra are completed by all the carboxylate groups of the two cit4− ligands in a monodentate mode, and two coordinated water molecules. Magnetic measurements indicate that the two Fe3+ ions are antiferromagnetically coupled below 200 K. A least-squares fit of variable-temperature (1.5–291 K) molar susceptibility data to a dimer model gave the coupling constant J/k = −6.35(7) K and Landé factor g = 2.052(9), where the spin-only Heisenberg–Dirac–van Vleck Hamiltonian is expressed as H = −2JS1S2.

Synthesis, spectrum and single crystal structure of a peroxovanadium complex of nitrilotriacetate ligand without water of crystallization, K2[VO(O2)NTA]

Abstract Crystals of the formula K2[VO(O2)NTA] with NTA = nitrilotriacetate have been prepared and characterized by IR and single-crystal X-ray diffraction methods. The structure of the anion of the complex shows that the vanadium atom has a distorted pentagonal bipyramidal environment surrounded by one oxo group, one peroxo group, three oxygen atoms and one nitrogen atom from the NTA ligand.

A mesoscopic molecular superparamagnet: preparation, crystal structure and magnetic properties of [Mn12O12(O2CMe)4 (O2CEt)12(H2O)4] · 2H2O · 4EtCO2H with an S = 9 ground state

Abstract The first dodecanuclear manganese aggregate containing heterocarboxylate ligands [Mn12O12(O2CMe)4(O2CEt)12(H2O)4] (1) has been prepared and structurally characterized. The single crystal X-ray diffraction of 1 shows that it is similar to [Mn12O12(O2CR)16(H2O)4] ( 2a , R = Me or 2b , R = Ph ) in its skeletal structure but it has a different crystal structure. Primary magnetism studies imply that 1 has an S = 9 spin ground state. A clear hysteresis loop was also observed for a polycrystalline sample of 1 · 2H2O · 4EtCOOH, but there was no anomaly in susceptibility down to 1.5 K. The cluster 1 represents another example of nanometre-sized molecular superparamagnets without particle size distribution.

A water-soluble μ2-oxo bridged diiron complex with terminally ligated iminodiacetate chelating ligands

Abstract The novel oxo-centered dinuclear iron complex K4[Fe2O(IDA)4] (1) (IDA = iminodiacetate) was synthesized by the air-oxidation of ferrous iron in an aqueous solution in the presence of iminodiacetate and characterized by IR, magnetic susceptibility, and X-ray crystallography methods. The structure contains dimeric units where the two crystallographically equivalent iron centers are linked by a μ2-oxo bridge at a symmetric center of crystallography, forming a stick-like core, [Fe2O]4+, and have distorted octahedral environments each with one tridentate and one “bidentate-like” IDA ligands completing the coordination sphere. The iron centers are antiferromagnetically coupled in the cluster since they are bridged by the μ2-oxo oxygen atom in the center of symmetry and this was confirmed by the magnetic susceptibility study.

μ-Glycine-O:O′-di-μ-oxo-bis[(gly­cinato-N,O)­oxomolybdenum(V)]

In the title compound, [Mo2O4(C2H4NO2)2(C2H5NO2)], two Mo atoms sit in the same distorted pentagonal bipyramid coordination environment. There are four ligand types: oxo-O, μ2-O, μ2-glycine and chelate glycine. There is an Mo—Mo bond between the two Mo atoms [2.552u2005(1)u2005A]. All amino groups participate in hydrogen bonding with O atoms of other molxadecules, thus connecting the molxadecules into a three-dimensional structure.

Hydrothermal synthesis and structure determination of a novel hexagonal ammonium molybdenum bronze, NH4Mo6O18

Abstract A new ammonium molybdenum bronze NH4Mo6O18 was synthesized by a hydrothermal method. Interesting features include the different location of the ammonium ions and the existence of lower-valence molybdenum atoms.