Ion-Pair Formation of 3m-Crown-m Ether (m = 5, 6) and Its Monobenzo Derivative Complex Ions with Several Pairing Anions in Water

Ion-pair formation constants (K MLX in mol-1·dm3) for M(B18C6)+, M(15C5)+, or M(B15C5)+ with pairing anions (X-) in water were determined by potentiometry with ion-selective electrodes at 25 °C over wide ranges of the ionic strength (I). The symbols B18C6, 15C5, and B15C5 denote benzo-18-crown-6 eth...

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Bibliographic Details
Published in:Journal of chemical and engineering data 2006-03, Vol.51 (2), p.604-608
Main Authors: Kudo, Yoshihiro, Fujihara, Ryo, Ohtake, Toshiaki, Wakasa, Masaomi, Katsuta, Shoichi, Takeda, Yasuyuki
Format: Article
Language:English
Subjects:
Chemistry
Exact sciences and technology
General and physical chemistry
Solution properties
Solutions
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Summary:Ion-pair formation constants (K MLX in mol-1·dm3) for M(B18C6)+, M(15C5)+, or M(B15C5)+ with pairing anions (X-) in water were determined by potentiometry with ion-selective electrodes at 25 °C over wide ranges of the ionic strength (I). The symbols B18C6, 15C5, and B15C5 denote benzo-18-crown-6 ether, 15-crown-5 ether, and benzo-15C5, respectively; metal salts, MX, used are sodium picrate (NaPic), KPic, NaBPh4, NaMnO4, and KMnO4. The K MLX values at I = 0 mol dm-3 (K MLX°) were evaluated from analyzing the I dependence of the log K MLX values determined. Then, effects of shapes of X-, the benzo group of the ethers, their ring sizes, and the shielding of the metal ions, M+, by the ethers on these K MLX° values were discussed in comparison with the values previously reported on M(18C6)X, M(15C5)Pic, and M(B15C5)Pic. Also, center-to-center distances in the M(18C6 derivatives)+-X- or M(15C5 ones)+-X- pairs were estimated from Bjerrum's equation.
ISSN:0021-9568
1520-5134
DOI:10.1021/je050423m