title: Oxo-vanadium(IV) dihydrogen phosphate: preparation, magnetic study, and heterogeneous catalytic epoxidation.
abstract: A layered oxo-vanadium(IV) dihydrogen phosphate, {VO(H2PO 4)2} n has been synthesized hydrothermally and characterized by several physicochemical methods. Single-crystal X-ray analysis (crystal system, tetragonal; space group, P4/ ncc; unit cell dimensions, a = b = 8.9632(4), c = 7.9768(32) A) of {VO(H2PO4) 2} n reveals that the compound has an extended two-dimensional structure. The VO2+ moieties are connected through bridging H 2PO4 (-) ions, and this type of connection propagates parallel to the crystallographic ab plane which gives rise to a layered structure. The layers are staked parallel to the crystallographic c axis with a separation between the layers of ca. 4.0 A. Magnetic susceptibility of {VO(H2PO4)2} n has been measured in the temperature range 2-300 K on a SQUID magnetometer. The magnetic property of {VO(H2PO4)2} n is explicable in the light of a two-dimensional quantum Heisenberg antiferromagnet model. Magnetic pathways are available through the dihydrogen-phosphato bridges within the layer and provide for weak antiferromagnetic interactions. Notably {VO(H2PO4)2} n catalyzes the epoxidation reaction of alkenes with tert-BuOOH in acetonitrile medium under heterogeneous condition.
authors.affiliation: Department of Chemistry, Jadavpur University, Kolkata 700 032, India.
authors.forename: Rupam
authors.initials: R
authors.lastname: Sen
authors.forename: Rajesh
authors.initials: R
authors.lastname: Bera
authors.forename: Ashis
authors.initials: A
authors.lastname: Bhattacharjee
authors.forename: Philipp
authors.initials: P
authors.lastname: Gütlich
authors.forename: Soumen
authors.initials: S
authors.lastname: Ghosh
authors.forename: Alok K
authors.initials: AK
authors.lastname: Mukherjee
authors.forename: Subratanath
authors.initials: S
authors.lastname: Koner