Differences in nature and stability of cadmium complexes with Group 15/Group 16 donor ligands as determined by multinuclear (phosphorus-31, selenium-77, cadmium-113) magnetic resonance and electrochemical techniques
| Autor: | Ray Colton, Jennifer Ebner, S. Richard Ellis, Alan M. Bond |
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| Rok vydání: | 1989 |
| Předmět: |
Ligand
Coordination number Inorganic chemistry Nuclear magnetic resonance spectroscopy Coupling (probability) Inorganic Chemistry NMR spectra database Perchlorate chemistry.chemical_compound Crystallography chemistry Isotopes of cadmium Phosphorus-31 NMR spectroscopy Physical and Theoretical Chemistry |
| Zdroj: | Inorganic Chemistry. 28:4509-4516 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic00324a017 |
| Popis: | Multinuclear ({sup 31}P, {sup 77}Se, {sup 113}Cd) magnetic resonance and electrochemical studies have been carried out to investigate the nature and stability of cadmium complexes with Ph{sub 2}PCH{sub 2}P(E)Ph{sub 2} (E = S (dpmS), Se (dpmSe)) and Ph{sub 2}P(E)CH{sub 2}P(E)Ph{sub 2} (E = S (dpmS{sub 2}), Se (dpmSe{sub 2})) in dichloromethane solution. The NMR studies indicate a cadmium preference for selenium or sulfur rather than phosphorus coordination in the dpmE complexes but are limited in scope with the NMR technique to examination rather than phosphorus coordination in the dpmE complexes but are limited in scope with the NMR technique to examination of the 1:2 cadmium to ligand stoichiometry due to the labile nature of the systems in the presence of excess ligand. Cadmium-selenium coupling is observed in some cases. The electrochemical reductions of both (Cd(dpmE){sub 2}){sup 2+} and (Cd(dpmE{sub 2}){sub 2}){sup 2+} at a mercury electrode are reversible two-electron processes. Ligand coordination numbers of 4 and 6 are attained with the dpmE complexes, but the dpmE{sub 2} complexes have a maximum ligand coordination number of 4 even at very high ligand to metal concentration ratios. The magnitudes of the calculated stability constants suggest that all of the dpmE and dpmE{submore » 2} complexes of cadmium(II) are essentially nondissociated in solution. The use of a Cd(Hg) amalgam electrode allows examination of the voltammetry of these cadmium systems in the presence of substoichiometric ligand concentrations and reemphasizes the high stability of the dpmE and dpmE{sub 2} complexes. The preference of cadmium for the group 16 donor atoms rather than phosphorus in the dpmE complexes is confirmed by an investigation of the interactions of cadmium perchlorate with PPh{sub 3} and PPh{sub 3}Se and by suitable mixing experiments. 25 refs., 4 figs., 5 tabs.« less |
| Databáze: | OpenAIRE |
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