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J Marrot

Publications and source records attributed to J Marrot.

5 recordsLinked to original sources
PubMed2001

Structural characterization and magnetic properties of sandwich-type tungstoarsenate complexes. Study of a mixed-valent VIV2/VV heteropolyanion.

Complexes K11Na1[As2W18(Mn(H2O))3O66]x27H2O (1) and Na12[As2W18(Co(H2O))3O66]x34H2O (2) have been characterized. 1 crystallizes in the orthorhombic space group Pnma, with a = 30.6484(4) A, b = 14.9946(2) A, and c = 19.17080(10) A (Z = 4), while 2 crystallizes in the monoclinic space group C2/c, with a = 14.124(2) A, b = 23.294(3) A, c = 32.247(3) A, and beta = 98.935(10) degrees (Z = 4). Structures of the anions of 1 and 2 are similar, the divalent metals adopting a square pyramidal environment. K11[As2W18(VO)3O66]x23H2O (3) crystallizes in the orthorhombic space group Pnma, with a = 30.6240(5) A, b = 14.9861(2) A, and c = 19.2651(3) A (Z = 4). The structure has revealed a disorder on two of the three metals linking the [alpha-AsW9O33]9- parts. For these two vanadium atoms, the V=O bonds are directed alternatively toward the inside or the outside of the [alpha-AsW9O33]9- cavity. The remaining vanadium shows a V=O bond always directed toward the outside of the cavity. Titration of VIV by CeIV revealed that 3 is the mixed-valent VIV2VV species. Magnetic measurements are in agreement with this formulation. The high-temperature molar magnetic susceptibility of a powdered sample of 3 clearly confirms the presence of two d1 centers. The two VIV are antiferromagnetically coupled, with J = -2.9 cm-1 and g = 1.93. Crystallographic data do not permit the location of the two VIV to be distinguished from the location of the VV. As expected, the Mn(II) are very weakly antiferromagnetically coupled in compound 1. The complex Na8[Ni(H2O)6]2[As2W18(Ni(H2O))3O66]x20H2O (4) has been synthesized. The anion crystallized with two octahedral [Ni(H2O)6]2+ as counterions. Magnetic data have been fitted assuming that the only exchange-coupled centers are the nickels of the polyanion. 4 exhibits an antiferromagnetic coupling with J = -1.7 cm-1, g = 2.27, and theta = -1.5 K.

Journal Article↗
PubMed2000

[H3N]

The structure of the title compound, pentane-1,5-diammonium aluminium(III) hydrogen bis(phosphate), (C(5)H(16)N(2))[AlP(2)O(8)H], obtained solvothermally at 473 K, has been determined by single-crystal X-ray diffraction. It consists of one-dimensional [AlP(2)O(8)H](2-) macroanions, connected to each other by pentanediammonium cations. Contrary to similar compounds with P/Al = 2, the three-dimensional structure is mainly obtained via a network of hydrogen bonds.

Journal Article↗
PubMed2000

Tetraaquabis(3,5-dicarboxybenzoato-O)cobalt(II)

The hydrothermal reaction of cobalt(II) chloride with trimesate (3, 5-dicarboxybenzoate) ions in aqueous solution gives the novel title complex, [Co(C(9)H(5)O(6))(2)(H(2)O)(4)]. The Co(II) ion lies on an inversion centre and is octahedrally coordinated to two trimesate anions and four water molecules. Hydrogen bonds ensure the three-dimensional architecture of the structure.

Journal Article↗