Solid state coordination chemistry of oxomolybdenum–organodiphosphonate materials: consequences of introducing xylyldiphosphonate components

Abstract

Hydrothermal syntheses were used to prepare compounds of the oxomolybdenum/xylyldiphosphonate and oxomolybdenum/M(II)–imine/xylyldiphosphonate families. Four compounds exhibited unadorned molybdophosphonate chains with the common {Mo₅O₁₅(O₃PR)₂}⁴⁻ building unit: (4,4′-H₂dpa)₂[Mo₅O₁₅(1,2-O₃PC₈H₈PO₃)]·H₂O (1·H₂O), (4,4′-H₂dpa)₂[Mo₅O₁₅(1,3-O₃PC₈H₈PO₃)] (2), [Cu(terpy)₂](H₃O)[Mo₅O₁₅(1,4-O₃PC₈H₈PO₃)]·H₂O (3·H₂O), and [Co(2,2′-bpy)₃](H₃O)[Mo₅(H₂O)O₁₄(1,4-O₃PC₈H₈PO₃)]·6H₂O (4·6H₂O). The pentanuclear building unit is preserved in the one-dimensional materials [{Cu(2,2′-bpy)₂}₂Mo₅O₁₅(1,4-O₃PC₈H₈PO₃)]·6H₂O (5·6H₂O), [{Cu(H₂O)₂(o-phen)}₂Mo₅O₁₅(1,4-HO₃PC₈H₈PO₃)]·4H₂O (6·4H₂O), and (4,4′-Hbpy)[Ni(H₂O)₄(4,4′-Hbpy)}Mo₅O₁₅(1,2-O₃PC₈H₈PO₃)]·4H₂O (8·4H₂O), while a modified, protonated pentanuclear core is observed for [{Cu(H₂O)(o-phen)}₂(1,4-HO₃PC₈H₈PO₃H)][{Cu(o-phen)(H₂O)}Mo₅O₁₄(OH)(1,4-O₃PC₈H₈PO₃)]₂ (7), a material that also exhibits two discrete one-dimensional substructures. In contrast, the one-dimensional [{Ni(H₂O)(tpypyz)}₂Mo₆O₁₈(H₂O)(1,4-O₃PC₈H₈PO₃)]·6H₂O (9·6H₂O) is constructed from hexanuclear molybdate clusters, and the two-dimensional [{Ni₂(H₂O)₄(tpypyz)}Mo₄O₁₀(1,4-O₃PC₈H₈PO₃)₂]·4H₂O (10·4H₂O) exhibits a unique tetranuclear core unit. The three-dimensional phase, [{Ni(H₂O)(2,2′-dpa)}₂Mo₅O₁₅(1,4-O₃PC₈H₈PO₃)]·2H₂O (11·2H₂O), reverts to the prototypical pentanuclear building unit. When the HF/Mo ratio of the reaction is increased from 4 : 1 to 8 : 1 or higher, three examples of oxyfluoromolybdate containing materials are observed: the one-dimensional [{Cu(o-phen)}₂Mo₂F₅O₄(OH)(H₂O)₄(1,3-O₃PC₈H₈PO₃)]·H₂O (12·H₂O); a structure displaying two discrete bimetallic oxyfluoride chains, [{Cu(terpy)₂(OH)(H₂O)}Mo₂F₄O₃(1,2-O₃PC₈H₈PO₃)][{Cu(terpy)(H₂O)}Mo₂F₃O₄(1,2-O₃PC₈H₈PO₃)]·H₂O (13·H₂O); and a three dimensional compound, [{Cu₃(bpy)₂}Mo₂F₂O₄(H₂O)₂(1,3-O₃PC₈H₈PO₃)₂] (14). The structures of these materials are compared to those of previously described phases of the oxomolybdate/M(II)–imine/organophosphonate and oxyfluoromolybdate/M(II)–imine/organophosphonate families.