Shivaiah, Vaddypally ; Das, Samar K. (2005) Polyoxometalate-supported transition metal complexes and their charge complementarity: synthesis and characterization of [M(OH)6Mo6O18 {Cu(Phen)(H2O)2}2][M(OH)6Mo6O18{Cu(Phen)(H2O) Cl}2]·5H2O (M = Al3+, Cr3+) Inorganic Chemistry, 44 (24). pp. 8846-8854. ISSN 0020-1669
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Official URL: http://pubs.acs.org/doi/abs/10.1021/ic050830j
Related URL: http://dx.doi.org/10.1021/ic050830j
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 title compounds [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 2a makes the charge difference. In both compounds, the geometries around copper centers are distorted square pyramidal and those around aluminum/chromium centers are distorted octahedral. Three lattice waters, from the formation of intermolecular O-H·····O hydrogen bonds, have been shown to self-assemble into an "acyclic water trimer" in the crystals of both 1 and 2. The title compounds have been synthesized in a simple one pot aqueous wet-synthesis consisting of aluminum/chromium chloride, sodium molybdate, copper nitrate, phenanthroline, and hydrochloric 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 P↑ . Crystal data for 1: α = 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 broad d-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 the monophenanthroline copper complexes to form POM-supported copper complexes 1c, 1a, 2c, and 2a. The ESR spectrum of compound 1 shows a typical axial signal for a Cu2+ (d9) system, and that of compound 2, containing both chromium(III) and copper(II) ions, may reveal a zero-field-splitting of the central Cr3+ ion of the Anderson anion, [Cr(OH)6Mo6O18]3-, with an intense peak for the Cu2+ ion.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to American Chemical Society. |
| ID Code: | 63393 |
| Deposited On: | 29 Sep 2011 04:25 |
| Last Modified: | 29 Sep 2011 04:25 |
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