Nuclearity control in molecular iron phosphates through choice of iron precursors and ancillary ligands.
The potential of a mono-organophosphate ester in assembling low to medium nuclearity iron complexes with novel topological architectures has been investigated. Reaction of 2,6-diisopropylphenyl dihydrogen phosphate (dipp-H(2)) with ferrous acetate under an inert atmosphere resulted in the formation of mononuclear, [Fe(II)(dipp-H)(2)(py)(4)] (1) (py = pyridine), dinuclear [Fe(III) (2)O(dipp-H)(4)(3,5-dmpz)(3)(thf)](3,5-dmpz)(thf)(3) (2) (3,5-dmpz = 3,5-dimethylpyrazole, thf = tetrahydrofuran), and trinuclear [Fe(III) (2)Fe(II)O(dipp-H)(6)(thf)(3)](collidine) (3) complexes by changing the ancillary amine used in the reaction. Use of a preformed mu(3)-oxo bridged trinuclear complex, [Fe(III) (3)O(O(2)CR)(6)(H(2)O)(3)]X (X = Cl and NO(3)), as the precursor yielded two tetranuclear iron phosphates, [Fe(III) (4)O(dipp)(3)(py)(4)(PhCOO)(4)](toluene)(3) (4) and [Fe(III) (4)O(dipp)(3)(OAc)(4)(py)(4)](py)(2) (5), having a core structure similar to those found in tetranuclear iron phosphonates. When FeCl(3)6H(2)O was used as the iron precursor, an unprecedented pentanuclear iron phosphate complex, [Fe(III) (5)O(dipp)(6)(py)(4)Cl(2)][pyH] (6) with a novel structure was isolated. Another pentanuclear complex having a similar core structure, [Fe(5)O(dipp)(6)(HO(2)CPh)(3)(CH(3)CN)(3)Cl] (7) was isolated on treatment of dipp-H(2) with the triangular complex, [Fe(III) (3)O(O(2)CPh)(6)(H(2)O)(3)]Cl in the absence of any added amine co-ligand. Compounds 1-7 have been characterized by analytical techniques, spectroscopic studies, single crystal X-ray diffraction studies, and magnetic measurements. The Mössbauer studies carried out at room temperature support the formulation of all the compounds.
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India), Fax: (+22) 2572-3480 http://www.chem.iitb.ac.in/∼rmv/.
Ramaswamy
R
Murugavel
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India), Fax: (+22) 2572-3480 http://www.chem.iitb.ac.in/∼rmv/.
Nayanmoni
N
Gogoi
(Magnetic studies), Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India).
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KG
Suresh
(Mössbauer studies), Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208 016 (India).
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S
Layek
(Mössbauer studies), Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208 016 (India).
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Verma