Potentiometric SCN− Selectivity of Polymer Membranes with Fixed Organotin Compounds

Moriuchi‐Kawakami, Takayo; Aoto, Hiroshi; Fujimori, Kunihide; Shibutani, Yasuhiko

doi:10.1246/cl.2001.1298

Cited by 1 publication

(1 citation statement)

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“…Interestingly, the zinc(II) center provides for a somewhat unusual selectivity pattern as compared to ISEs based on other metalloorganic ionophores. For [36,37]) and a zinc(II) tetraphenylporphyrin (log K pot SCN;NO3 (SSM) À 2.4, as calculated from reported log K pot I;j [8]). Since the above selectivity data suggested the possibility of one thiocyanate interacting with both zinc(II) centers of the dinuclear ionophore complex, we were interested in seeing the selectivity of this electrode for organic cations with two distinct coordinating groups.…”

Section: Resultsmentioning

confidence: 99%

Ion‐Selective Electrodes for Thiocyanate Based on the Dinuclear Zinc(II) Complex of a Bis‐N,O‐bidentate Schiff Base

2004

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An ion selective electrode based on the dinuclear complex formed by two zinc(II) ions and two molecules of the bis-N,O-bidentate Schiff base 2,2'-[methylenebis(4,1-phenylenenitrilomethylidyne)]bisphenol exhibits thiocyanate selectivity with a good discrimination of nitrite, nitrate, and azide. The selectivities of electrode membranes with various compositions indicate that this potentiometric selectivity is based on the formation of a 1 : 1 complex between the thiocyanate anion and the dinuclear ionophore. The 2 : 1 ratio of thiocyanate ions and the dinuclear ionophore that results from higher ratios of cationic sites and ionophore worsens the selectivity, suggesting that binding of a thiocyanate to both zinc(II) centers of the dinuclear ionophore is not favorable. Interestingly, the selectivity patterns of these electrodes differ radically from that of a highly sulfate selective electrode based on a compound reported previously to be the analogous mononuclear 1 : 1 complex of zinc(II) and the same Schiff base. It is suggested that the previously reported 1 : 1 complex with zinc(II) may indeed have been a polymer of the same elemental composition.

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Section: Resultsmentioning

confidence: 99%