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.
Murugavel
Ramaswamy
R
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India), Fax: (+22) 2572-3480 http://www.chem.iitb.ac.in/∼rmv/.
Gogoi
Nayanmoni
N
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India), Fax: (+22) 2572-3480 http://www.chem.iitb.ac.in/∼rmv/.
Suresh
K G
KG
(Magnetic studies), Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India).
Layek
S
S
(Mössbauer studies), Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208 016 (India).
Verma
H C
HC
(Mössbauer studies), Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208 016 (India).