| Abstract
| - Two Anderson-type heteropolyanion-supported copper phenanthroline complexes, [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2]1+ (1c) and [Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]1- (1a) complement their charges in one of the titlecompounds [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2][Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]·5H2O ≡ [1c][1a]·5 H2O ≡ 1.Similar charge complementarity exists in the chromium analogue, [Cr(OH)6Mo6O18{Cu(phen)(H2O)2}2][Cr(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]·5 H2O ≡ [2c][2a]·5 H2O ≡ 2. The chloride coordination to copper centers of 1a and 2amakes the charge difference. In both compounds, the geometries around copper centers are distorted squarepyramidal and those around aluminum/chromium centers are distorted octahedral. Three lattice waters, from theformation of intermolecular O−H·····O hydrogen bonds, have been shown to self-assemble into an “acyclic watertrimer” in the crystals of both 1 and 2. The title compounds have been synthesized in a simple one pot aqueouswet-synthesis consisting of aluminum/chromium chloride, sodium molybdate, copper nitrate, phenanthroline, andhydrochloric acid, and characterized by elemental analyses, EDAX, IR, diffuse reflectance, EPR, TGA, and single-crystal X-ray diffraction. Both compounds crystallize in the triclinic space group P1̄. Crystal data for 1: a = 10.7618(6),b = 15.0238(8), c = 15.6648(8) Å, α = 65.4570(10), β = 83.4420(10), γ = 71.3230(10)°, V = 2182.1(2) Å3.Crystal data for 2: a = 10.8867(5), b = 15.2504(7), c = 15.7022(7) Å, α = 64.9850(10), β = 83.0430(10), γ= 71.1570(10)°, V = 2235.47(18) Å3. In the electronic reflectance spectra, compounds 1 and 2 exhibit a broadd−d band at ∼700 nm, which is a considerable shift with respect to the value of 650−660 nm for a square-pyramidal [Cu(phen)2L] complex, indicating the coordination of [M(OH)6Mo6O18]3- POM anions (as a ligand) to themonophenanthroline copper complexes to form POM-supported copper complexes 1c, 1a, 2c, and 2a. The ESRspectrum of compound 1 shows a typical axial signal for a Cu2+ (d9) system, and that of compound 2, containingboth chromium(III) and copper(II) ions, may reveal a zero-field-splitting of the central Cr3+ ion of the Andersonanion, [Cr(OH)6Mo6O18]3-, with an intense peak for the Cu2+ ion.
- A simple one pot aqueous wet-synthesis, consisting of aluminum/chromium chloride, sodium molybdate, copper nitrate, phenanthroline, and hydrochloric acid results in the formation of polyoxometalate-based ion-pair compounds. Two polyoxometalate-supported copper phenanthroline complexes complement their charges in the title compounds. An acyclic water trimer is identified, which is stabilized via supramolecular hydrogen bonding interactions with terminal and bridging oxygen atoms of Anderson heteropoly anions and copper-coordinated water molecules.
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