Structural consequences of the steric effects of the organoimine ligand in the oxovanadium–organophosphonate/copper–mephenterpy family of hybrid oxides (mephenterpy = 4′-(4-methyphenyl)-2,2′∶6′,2″-terpyridine)

Abstract

Hydrothermal reactions of CuSO₄·5H₂O, Na₃VO₄, 4′-(4-methylphenyl)-2,2′∶6′,2″-terpyridine (mephenterpy) and the appropriate diphosphonic acid provided a series of materials of the Cu(II)–mephenterpy/oxovanadium organophosphonate family. Four one-dimensional compounds were isolated: [{Cu(mephenterpy)}(VO₂)(HO₃PCH₂PO₃)] (1), [{Cu(mephenterpy)}₂(V₃O₆)(O₃PCH₂CH₂PO₃)(HO₃PCH₂CH₂PO₃)] (2), [{Cu(mephenterpy)}(VO₂)(HO₃PCH₂CH₂CH₂PO₃)] (3) and [{Cu(mephenterpy)}₂(V₂O₅)₂(O₃PCH₂CH₂CH₂PO₃)] (4). Although all share a common dimensionality, the detailed connectivities within the chains result in four distinct vanadophosphonate substructures: {(VO₂)(HO₃PCH₂CH₂PO₃)}²ⁿ⁻_n chains in 1, {(V₃O₆)(O₃PCH₂CH₂PO₃)(HO₃PCH₂CH₂PO₃)}⁴ⁿ⁻_n chains in 2, [(VO₂)₂{HO₃P(CH₂)₃PO₃}₂]⁴⁻ rings in 3 and [(V₂O₅)₂{O₃P(CH₂)₃PO₃}]⁴ⁿ⁻_n chains in 4. When the diphosphonate tether is a butylene group, the copper phase [Cu(mephenterpy){HO₃P(CH₂)₄PO₃H}]·H₂O (5) is isolated.