NMR and DFT studies of the complexation of W(VI) and Mo(VI) with 3-phospho-D-glyceric and 2-phospho-D-glyceric acids.
Multinuclear ((1)H, (13)C, (17)O, (31)P, (95)Mo, (183)W) magnetic resonance spectroscopy (1D and 2D) has been used to study the complexation of molybdate(VI) and tungstate(VI) with 3-phospho-D-glyceric and 2-phospho-D-glyceric acids. 3-Phospho-D-glyceric acid forms four and five complexes, respectively, with molybdate and tungstate. These have MO(2)(2+) centres, and involve the carboxylate and the adjacent OH groups. Two isomeric 1:2 (metal-ligand) complexes are detected, in addition to one mononuclear species having MO(3) centres and involving the ligand in a tridentate chelation and a dominant 12:4 species with both tungstate(VI) and molybdate(VI). The dominant 12:4 species can be seen as two 1:2 complexes bound together in a ring through two diphosphometalate moieties, derived from heptamolybdate or heptatungstate, respectively, by inclusion of two phosphate groups from the ligands. Tungstate is also able to form an additional 2:1 tridentate species. 2-Phospho-D-glyceric acid does not interact with tungstate but is able to form one phosphomolybdate species with molybdate, which can be regarded as a heptamolybdate derivative. Density functional theory (DFT) calculations were performed for 1:2 complexes, including calculations on the relative energies of the 1:2 complexes detected in related systems, to validate previously proposed structures. The results are compared with those obtained from multinuclear NMR spectroscopy.
Ramos
M Luísa
ML
Departmento de Química, Universidade de Coimbra, 3004-535, Coimbra, Portugal. mlramos@ci.uc.pt
Justino
Licínia L G
LL
Gil
Victor M S
VM
Burrows
Hugh D
HD
D005988:Glyceric Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D014414:Tungsten / Q000737:chemistry*
D005988:Glyceric Acids; D009942:Organometallic Compounds; D008982:Molybdenum; D014414:Tungsten