TY - JOUR
T1 - Complexation of Silicic Acid with Tiron in Aqueous Solution under near Natural Condition
AU - Bai, Shuqin
AU - Tsuji, Yutaka
AU - Okaue, Yoshihiro
AU - Yokoyama, Takushi
N1 - Funding Information:
Acknowledgements The present work is supported by National Natural Science Foundation of China (21066006) and Inner Mongolia Natural Science Foundation (2010MS0617). This study also supported by Grant-in-Aid for the Global COE Program, “Science for Future Molecular Systems” from the Ministry of Education, Culture, Science, Sports and Technology of Japan and Kyushu University Interdisciplinary Programs in Education and Projects in Research Development.
PY - 2011/2
Y1 - 2011/2
N2 - The formation of a silicic acid-tiron (a derivative of catechol) complex was investigated in aqueous solution with various molar ratios of tiron to silicic acid (tiron/Si) or with various ρH using 29Si NMR. Only the 1:3 silicic acid-tiron complex was detected in despite of the range of tiron/Si molar ratios. This complex is stable in the pH range from 6 to 10. This indicates that the formation of a hydrogen bond (SiOH. . .O- in tiron), due to dissociation of H+ from hydroxy groups of tiron, may be a trigger for the formation of the complex. Around ρH=6, the formation of the complex occurs when the tiron/Si molar ratio is larger than 3 and most of silicic acid is converted to the complex when the ratio is larger than 25. Based on the temperature dependence of the 29Si NMR spectra for the complex, the existence of two possible meridional and facial isomers was confirmed. The conditional formation constant for the 1:3 silicic acid-tiron complex was defined as Eq. 8 and estimated to be 2.0 mol-1 .dm3 for the facial complex and 4.1 mol-1 dm3 for the meridional complex, respectively.
AB - The formation of a silicic acid-tiron (a derivative of catechol) complex was investigated in aqueous solution with various molar ratios of tiron to silicic acid (tiron/Si) or with various ρH using 29Si NMR. Only the 1:3 silicic acid-tiron complex was detected in despite of the range of tiron/Si molar ratios. This complex is stable in the pH range from 6 to 10. This indicates that the formation of a hydrogen bond (SiOH. . .O- in tiron), due to dissociation of H+ from hydroxy groups of tiron, may be a trigger for the formation of the complex. Around ρH=6, the formation of the complex occurs when the tiron/Si molar ratio is larger than 3 and most of silicic acid is converted to the complex when the ratio is larger than 25. Based on the temperature dependence of the 29Si NMR spectra for the complex, the existence of two possible meridional and facial isomers was confirmed. The conditional formation constant for the 1:3 silicic acid-tiron complex was defined as Eq. 8 and estimated to be 2.0 mol-1 .dm3 for the facial complex and 4.1 mol-1 dm3 for the meridional complex, respectively.
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U2 - 10.1007/s10953-011-9648-8
DO - 10.1007/s10953-011-9648-8
M3 - Article
AN - SCOPUS:79551642321
SN - 0095-9782
VL - 40
SP - 348
EP - 356
JO - Journal of Solution Chemistry
JF - Journal of Solution Chemistry
IS - 2
ER -