Novel building units in the construction of materials of the oxomolybdate–organodiphosphonate/copper(II)–dipodal-organonitrogen ligand system: Structural influences of dipodal ligand tether length and flexibility
作者:Mark Bartholomä、Hoi Chueng、Steven Pellizzeri、Kenneth Ellis-Guardiola、Stephanie Jones、Jon Zubieta
DOI:10.1016/j.ica.2012.01.011
日期:2012.7
The hydrothermal reactions of copper(II) acetate, MoO3, 1,4-butylenediphosphonic acid and a ligand of the N,N,N',N'-tetrakis(pyridine-2-ylmethyl)alkyl-alpha,omega-diamine (Ln, where n is the number of methylene groups) in the presence of HF provided crystals of [Cu-2(L7)(H2O)(2)}Mo5O15O3P(CH2)(4)PO3}]center dot 2H(2)O (1 center dot 2H(2)O) and [Cu-2(L5)}Mo6O18(H2O)O3P(CH2)(4)PO3}]center dot 14H(2)O (2 center dot 14H(2)O). Compound 1 contains the common pentanuclear cluster building block Mo5O15(O3PR)(2)}(4-), extending into one-dimensional chains through the alkyl tethers of the diphosphonate ligand. Each pentanuclear subunit bonds to four copper(II) sites of the Cu-2(L7)(H2O2)}(4+) subunits that serve to link each chain to five adjacent chains to propagate the structure in three dimensions. The Cu/Mo/P/O inorganic substructure which arises from this juxtaposition of building motifs is a one-dimensional Cu2Mo5O15(O3P-)(2)} unit consisting of clusters linked through Cu(II) sites. The alkyl arms of the diphosphonate and nitrogen ligands radiate outward to link to adjacent chains and propagate the structure in three-dimensions. In contrast, compound 2 exhibits a hexanuclear building unit Mo6O18(H2O)(O3P-)(2)}(4-), which again extends into a chain through the tethering diphosphonate ligands. Each cluster bonds to four Cu(II) centers to generate one-dimensional inorganic substructures of the type Cu2Mo6O18(H2O)(O3P-)(2)}(n). In contrast to 1, the Cu-2(L5)}(4+) subunits of 2 associate with a single chain, rather than radiating outward to link to adjacent chains. Consequently, the three-dimensional expansion is effected through the diphosphonate tethers. (C) 2012 Elsevier B.V. All rights reserved.