Interactions of Aluminum(III) with Phosphates

Károly Atkári, Tamás Kiss, Roberta Bertani, R. Bruce Martin

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In order to obtain information about aluminum(III)-phosphate interactions, potentiometric measurements were carried out to characterize the complex forming properties of Al(III) with organic phosphates, phosphonates, and nucleoside-5′-monophosphates. The aluminum(III)-orthophosphate system is difficult to study due to AlPO4 precipitation. To overcome this problem, the stability constant logarithms of the 1:1 Al(III) complexes of ligands with the same donor groups (log K1:1) were plotted against the basicities of the ligands (log KPO3H). The resulting linear free energy relation (LFER) indicates that organic phosphates, phosphonates, and uridine-, thymidine-, and guanosine 5′-monophosphates similarly bind Al(III). Adenosine and cytidine 5′-monophosphate fall above the LFER owing to the presence of a second microform with the nucleic base protonated and a hydroxide bound to the Al(III). From the LFER the log stability constant for Al(III) binding to HPO42- is estimated as 6.13 ± 0.05. From the weakness of any soluble orthophosphate complexes of Al(III) we confirm the importance of citrate as the main small molecule Al3+ binder in the blood serum. The study includes investigation of Al(III) binding to di- and triphosphates, which bind metal ion differently than monophosphates. Structures of the complexes were supported by 31P NMR measurements.

Original languageEnglish
Pages (from-to)7089-7094
Number of pages6
JournalInorganic Chemistry
Issue number24
Publication statusPublished - Dec 1 1996

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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    Atkári, K., Kiss, T., Bertani, R., & Bruce Martin, R. (1996). Interactions of Aluminum(III) with Phosphates. Inorganic Chemistry, 35(24), 7089-7094.