Construction of metal-organic oxides from molybdophosphonate clusters and copper-bipyrimidine building blocks

N. Gabriel Armatas, Wayne Ouellette, Kelly Whitenack, Joshua Pelcher, Hongxue Liu, Erin Romaine, Charles J. O'Connor, Jon Zubieta

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

A series of organic-inorganic hybrid materials of the copper(II)- molybdophosphonate family have been prepared using conventional hydrothermal conditions. The reactions of MoO3, copper(II) acetate, bipyrimidine (bpyr), a phosphonic acid, and water at temperatures below 160 °C and in the presence of a mineralizer such as acetic acid or HF provided crystalline samples of materials of the general class {Cu2(bpyr)} 4+/MoxOy-phosphonate. The recurrent themes of the structures are the presence of the binuclear {Cu2(bpyr)} 4+ and pentanuclear (Mo5O15(O 3PR)2)4- building blocks. For the alkylphosphonate-containing materials, [{Cu2(bpyr) 2}Mo5O15(O3PCH3) 2]-2.5H2O (1 -2.5H2O) is two-dimensional and exhibits {Cu(bpyr)}.,217 chains, while [{Cu2(bpyr)(H 2O)}Mo5O15(O3PCH2CH 3)2] (2) is three-dimensional. The diphosphonate series of materials {{Cu2(bpyr)}4+[Mo5O 15{O3P(CH2)nPO3}] 4- with n = 2-6 (4,5,7-9) in all cases contain the characteristic [Mo5O15{O3P(CH2),PO 3}]n2n+ chains, linked through {Cu 2(bpyr)}4+ rods into three-dimensional frameworks. When n = 1, the threedimensional phase [{Cu2(bpyr)}MoO2(HO 3PCH2PO3)2] • 2H2O (3- 2H2O) is obtained, the exclusive example of a structure constructed from isolated {MoO8} polyhedra rather than pentamolybdate clusters. The Ni(II)-containing phase [{Ni2(bpyr)(H 2O)4}Mo5O15{O3P(CH 2)3PO3}]-9H2O (6-9H2O) was also prepared and compared to the structure of the Cu(II) analogue, [{Cu2(bpyr)(H2O)4}Mo5O 15{O3P(CH2)3PO3}]-3H 2O (5-3H2O). Magnetic susceptibility studies of the compounds revealed that the magnetic behavior was consistent in all cases with antiferromagnetically coupled dimers. However, the magnitude of the exchange coupling was clearly dependent on the orientation of the M(II) mean equatorial or basal planes relative to the bipyrimidine plane. Thus, when the metal and bipyrimidine planes are nearly coplanar, the Jvalues are in the -77 to -87 cm1 range, while J values of -2 to -5 cm1 are observed for the compounds with out-of-plane orientations.

Original languageEnglish (US)
Pages (from-to)8897-8910
Number of pages14
JournalInorganic Chemistry
Volume48
Issue number18
DOIs
StatePublished - Sep 21 2009

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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