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SYNTHESIS CHARACTERIZATION AND STUDY OF HYDROGEN BONDING IN TRANSITION METAL FLUORIDE COMPLEXES

Hafeez, Samia (2001) SYNTHESIS CHARACTERIZATION AND STUDY OF HYDROGEN BONDING IN TRANSITION METAL FLUORIDE COMPLEXES. PhD thesis, Bahauddin Zakariya University, Multan.

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Abstract

Transition metal complexes such as those of copper, nickel, iron and cobalt in which there is a fluoride either attached to the metal ion or uncoordinated as a counter anion are still relatively rare and there are only few examples in the literature. In the present studies work has been carried out on the "synthesis, characterization and study of hydrogen bonding in transition metal fluoride complexes". A series of metal fluoride complexes have been prepared with various nitrogen donor ligands. The ligands used for complexation were imidazole, nicotinamide, 1,10-phenanthroline and 1,3diaminopropane. These nitrogen donor ligands have been found to cause d- block metal fluorides to dissolve in methanol/ethanol. From some of these solutions metal fluoride hydrate complexes were isolated. Metal fluorides used for the purpose were mainly copper (II) fluoride, nickel (II) fluoride, cobalt (II) fluoride, manganese (II) fluoride, iron (II) fluoride and chromium (III) fluoride. The metal complexes were subjected to metal analysis and spectral studies. From these studies it has been found that the complexes have 1:2(Metal: Ligand) ratios. On the basis of spectroscopic studies it was suggested that ligands, 1,10-phenanthroline and 1,3-diaminopropane in these complexes acted as bidentate and coordinated to the metals through pyridine nitrogen and -NH2 groups respectively. In case of imidazole and nicotinamide, these ligands acted as monodentate and coordinated to the metals through pyrrole nitrogen and pyridine nitrogen respectively. These complexes were formulated as: [M(LL)2F2].xH2O where M= Cu(II), Ni(II), Co(II), Fe(II), Mn(II), [M(LL)2F2]F .xH2O where M=Cr(III) and LL= bidentate ligands [ML2F2(H2O)2].xH2O where M= Cu(II), Ni(II), Co(II), Fe(II), Mn(II) and [ML2F2(H2O)2]F.xH2O where M= Cr(III) and L= monodentate ligands. In all these complexes fluoride was directly coordinated to metal. Conductance data supported the non-ionic form of these complexes except that of chromium complex which was 1:1 electrolyte. Electronic spectra and magnetic moment measurements indicated octahedral geometry around M(II) and M(III) ions. Infrared studies also suggested that extensive hydrogen bonding was present in these complexes. Broad continua with range of 3500-3100 cm-1, 1750-1040 cm-1 and 960-300 cm-1 in these complexes were indicative of a hydrogen bonding network.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Hydrogen Bonding, Metal Fluoride, Imidazole, Nicotinamide, 1-10-Phenanthroline, 1-3diaminopropane
Subjects:Physical Sciences (f) > Chemistry(f2)
ID Code:310
Deposited By:Mr Ghulam Murtaza
Deposited On:17 Jun 2006
Last Modified:04 Oct 2007 21:00

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