The coordination chemistry of periodate and tellurate ligands
The coordination chemistry of periodate and tellurate ligands
Complexes of general formula M'MIO6 have been synthesised for M = Ni, Mn, Ge, Sn and Pb all in the +4 oxidation state, and M' = Na, K, NH4, Rb and Cs. X-ray powder diffraction (XPD) determined that a layered structure is adopted by these complexes, with space group P312 for M = Ni, Ge and P6322 for M = Sn, Pb. Multi-edge EXAFS was used to help assign lattice positions for the M and I atoms that could not be unambiguously determined by XPD, and to deduce the layered structure for the manganese complexes. The paramagnetism of the nickel complexes has been attributed to the presence of octahedral Ni(II) centres, with Ni(III) being observed in the Na and K salts. Temperature independent paramagnetism may also contribute.
Several periodate and tellurate complexes adopting discrete molecular structures have also been synthesised and their structures determined by the use of IR, UV/Visible 125Te NMR and multi-edge EXAFS spectroscopy. The crystal structure of Rb2Na4[OsO2(H2TeO6)2].16H2O has been determined. EXAFS studies have shown that the Ru(VI) bis-tellurate and the Os(VI) bis-periodate and tellurate complexes are all similar in structure, with two bidentately bound ligands and a trans-oxo group on the metal centre. The silver(III) and gold(III) bis-tellurates contain a square planar metal centre with two bidentate tellurate ligands. The manganese(IV) tris-tellurate complex, Na7K[Mn(H2TeO6)3].3H2O, also contains bidentate ligands and is similar in structure to the analogous manganese(IV) tris-periodate. Several other complexes previously reported in the literature have also been examined by these techniques with attempts to synthesise new examples.
The co-ordination chemistry of telluracyclopentane (tcp), Te(CH2)4, has been investigated. Pd(II) and Pt(II) halide complexes of general formula MX2(tcp)2 (X = halide) were synthesised and characterised by 125Te NMR, IR and UV/Visible spectroscopy. All complexes exist as trans isomers in the solid state and solution, with the exception of [Pt(tcp)2Cl2] which is cis in the solid state and a mixture of isomers in solution.(DX183,773)
University of Southampton
1994
Oldroyd, Richard Duncan
(1994)
The coordination chemistry of periodate and tellurate ligands.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Complexes of general formula M'MIO6 have been synthesised for M = Ni, Mn, Ge, Sn and Pb all in the +4 oxidation state, and M' = Na, K, NH4, Rb and Cs. X-ray powder diffraction (XPD) determined that a layered structure is adopted by these complexes, with space group P312 for M = Ni, Ge and P6322 for M = Sn, Pb. Multi-edge EXAFS was used to help assign lattice positions for the M and I atoms that could not be unambiguously determined by XPD, and to deduce the layered structure for the manganese complexes. The paramagnetism of the nickel complexes has been attributed to the presence of octahedral Ni(II) centres, with Ni(III) being observed in the Na and K salts. Temperature independent paramagnetism may also contribute.
Several periodate and tellurate complexes adopting discrete molecular structures have also been synthesised and their structures determined by the use of IR, UV/Visible 125Te NMR and multi-edge EXAFS spectroscopy. The crystal structure of Rb2Na4[OsO2(H2TeO6)2].16H2O has been determined. EXAFS studies have shown that the Ru(VI) bis-tellurate and the Os(VI) bis-periodate and tellurate complexes are all similar in structure, with two bidentately bound ligands and a trans-oxo group on the metal centre. The silver(III) and gold(III) bis-tellurates contain a square planar metal centre with two bidentate tellurate ligands. The manganese(IV) tris-tellurate complex, Na7K[Mn(H2TeO6)3].3H2O, also contains bidentate ligands and is similar in structure to the analogous manganese(IV) tris-periodate. Several other complexes previously reported in the literature have also been examined by these techniques with attempts to synthesise new examples.
The co-ordination chemistry of telluracyclopentane (tcp), Te(CH2)4, has been investigated. Pd(II) and Pt(II) halide complexes of general formula MX2(tcp)2 (X = halide) were synthesised and characterised by 125Te NMR, IR and UV/Visible spectroscopy. All complexes exist as trans isomers in the solid state and solution, with the exception of [Pt(tcp)2Cl2] which is cis in the solid state and a mixture of isomers in solution.(DX183,773)
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Published date: 1994
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Local EPrints ID: 458465
URI: http://eprints.soton.ac.uk/id/eprint/458465
PURE UUID: 10c9ae7e-08b1-4f62-b403-50bf9079c692
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Date deposited: 04 Jul 2022 16:49
Last modified: 04 Jul 2022 16:49
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Author:
Richard Duncan Oldroyd
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