
TY  - JOUR
A1  - Best, WM 
A1  - Harrowfield, JM 
A1  - Shand, TM 
A1  - Stick, RV 
T1  - Aluminum(III) Coordination to Hydroxy Carboxylates: the Influence of Hydroxy Substituents Enabling Tridentate Binding
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1994
VL  - 47
IS  - 11
SP  - 2023
EP  - 2031
KW  - 
UR  - https://doi.org/10.1071/CH9942023 
N2  - Potentiometric evalution of the interaction between aluminium(III) and the hydroxy  carboxylates 3-deoxy-D-ribo-hexonate (L1H) and 2,5-dihydroxypentanoate (L2H) provided evidence for the formation of 1:1 complexes only, though with the ligand being present in singly, doubly and quadruply deprotonated forms in the hexonate complexes, and in singly, doubly and triply deprotonated forms in those of the pentanoate. At 298 K in aqueous media, I = 0.1 ( NaCl ), equilibrium quotient values obtained through use of the programs PKAS and BEST were: -log([(L1)-][H+]/[L1H])(or pKa(L1H))= 3.58±0.03 log([(AlL1)2+]/[Al3+][(L1)-])=1.97±0.03 log([(AlH-1L1)+][H+]/[(AlL1)2+])= -2.83±0.05 log([(AlH-3L1)-][H+]2/[(AlH-1L1)+])= -9.17±0.08 -log([(L2)-][H+]/[L2H])(or pKa(L2H))= 3.92±0.03 log([(AlL2)2+]/[Al3+][(L2)-])= 2.04±0.03 log([(AlH-1L2)+][H+]/[AlL2)2+])= -3.14±0.06 log([AlH-2L2][H+]/[(AlH-1L2)+])= -2.25±0.09 The very close similarity of the results for 3-deoxy-D-ribo-hexonate (3-deoxygluconate) and those known for D(+)-gluconate has led to the suggestion that the complexes of the quadruply  deprotonated ligands may involve trialkoxo coordination through the C1, C5 and C6 substituents. 
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