The efficiencies of many rigidly held cis-aquahydroxotetraazacobalt(III) complexes in promoting the hydrolysis of phosphate esters (BDNPP, BNPP, NPP) have been compared. The phosphate diester bond in ((trpn)Co(OH)(BNPP)) $ sp{+}$ is hydrolyzed at about the same rate as BNPP bound to a real enzyme from Enterobacter aerogenes and about 10$ sp{10}$ times more rapidly than free BNPP. The dramatic increase in the activity of the Co(III) complex with change in the tetraamine ligand structure can be explained in terms of a detailed mechanism of the reaction. / Co(III) complexes, ((tren)Co(OH$ sb2)$(OH)) $ sp{2+}$ and ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ have been shown to be highly efficient in promoting the hydrolysis of phosphate di- and monoesters with poor leaving groups. ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ promoted hydrolysis of phosphate monoesters leads to a novel binuclear phosphato complex which is a model for the active site of Purple Acid Phosphatases. / For the first time it has been shown that hydrolysis of carboxylic esters catalyzed by ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ is truly catalytic. The hydrolytic activity of ((trpn)Co(OH$ sb2)$(OH)) $ sp{2+}$ has been linked to the fact that this complex chelates carboxylic acids as shown by $ sp{13}$C NMR spectroscopy and the crystal structure of ((trpn)Co($ eta sp2$-OCC(CH$ sb3) sb3) rbrack sp{2+}$. This complex is the first example of a cobalt(III) complex in which carboxylic acid is chelated.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74289 |
| Date | January 1989 |
| Creators | Banaszczyk, Mariusz G. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001066239, proquestno: AAINN63519, Theses scanned by UMI/ProQuest. |
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