Chemical Properties of Expanded Porphyrins and their Application to Analytical Chemistry

通过三吡喃衍生物与联吡咯的缩合反应，合成了一种扩展的卟啉--2，23-二乙基-8，17-二(2-乙氧基乙氧基乙基)-3，7，12，13，18，22，22-六甲基卟啉(H3sap)，并建立了测定阴离子和金属离子的高选择性方法。在氟离子存在下，通过离子对络合物[H5sap F]^+的形成，在450 nm处与氟反应，发出680 nm的荧光增强。由于本方法是基于氟离子与苏必林的直接反应，因此铝(III)离子的200倍和铁(III)离子的2000倍不干扰氟的测定。将该方法应用于不同水样中氟离子的测定，并用停流法研究了详细的反应机理。生成和分解…的速率常数和活化能[H&lt；@D25@&gt；D2sap F]&lt；@d1+@&gt；d1；d2f@&gt；d2=(1.53 0.03)x10&lt；@d17@&gt；d1mol&lt；@d1-1@&gt；@d13@&gt；d1 S&lt；@d1-1@&gt；d1(25ﾟC)，DELTAH&lt；@d1*@&gt；D1=24.1(]sy.+-.[)0.3kJ摩尔；@d1-1@；d1，增量；@d1*@；d1=-26.6(]s.+-.[)1.0J摩尔；@d1-1@及k&lt；@D2d@&gt；D2=(4.08(]SY.+-.[)0.08)x10&lt；@D15@&gt；；d1-1@D1(25ﾟC)，d1-1@d1；d1，d1-1@d1；d1。其速率常数比氟离子的质子转化速率小10000倍。结果表明，存在一个变形的皂啉结构的预平衡，以接受氟离子。锌(II)络合物形成和解离的速率常数为：k&lt；@D2f@&gt；D2=(11.8(]SY.+-.[)0.2)x10&lt；@D14@&gt；D1(25ﾟC)mol&lt；@D1-1@&gt；D1 dm&lt；@D13@&gt；d1 S；@d1-1@&gt；d1；D1=82.0kJ摩尔；@d1-1@；d1，DELTAS&lt；@D1(]SY.Thermod.[)@&gt；D1=127(]SY.+-.[)3J摩尔；@d1-1@kt；d1；d1-1@&gt；d1，d2=7.66(]s.+-.[)0.71(25ﾟC)；@d1(]SY.Thermod.[)@&gt；d1=82.9(]sy.+-.[)6.5kJ mol&lt；@d1-1@&gt；d1，DELTAS&lt；@D1(]SY.Thermod.[)@&gt；D1=126(]SY.+-.[)22 J mol&lt；@d1-1@&gt；d1 K&lt；@d1-1@。锌(II)络合物的生成速率是锌(II)卟啉生成速率的1000倍，但仍比水中锌(II)离子的解离速率小100倍。氟离子对络合物被提取到氯仿中，化学物种为[H_4sap F^-]，也显示出荧光。较少

An Expanded Porphyrin, 2,23-diethyl-8,17-bis (2-ethoxycarbonylethyl) -3,7,12,13,18,22,22-hexamethylsapphyrin (H_3sap), was synthesized by condensation of tripyrrane derivative with bipyrrole and highly selective methods for the determination of anions and metal ions were developed.The sapphyrin reacts with fluoride to give out an enhanced fluorescence intensity at 680 nm on excitation at 450 nm in the presence of fluoride ion as small as parts per billion level via the ion-pair complex, [H_5sap F]^+ formation. Since the present method is based on a direct reaction of the fluoride ion with the sappyrin, a 200-fold amount of the aluminum (III) ion and 2000-fold amount of the iron (III) ion over the fluoride ion did not interfere with determination of the fluoride. The method was applied to determination of the fluoride ion in various water samples.The detailed reaction mechanism was studied by using stopped-flow method. The rate constants and activation energies for the formation and dis … More sociation reactions of[H<@D25@>D2sap F]<@D1+@>D1 were found to be k<@D2f@>D2=(1.53 0.03)x10<@D17@>D1 mol<@D1-1@>D1 dm<@D13@>D1 s<@D1-1@>D1(25ﾟC), DELTAH<@D1*@>D1=24.1(]SY.+-.[) 0.3 kJ mol<@D1-1@>D1, DELTAS<@D1*@>D1=-26.6(]SY.+-.[)1.0J mol<@D1-1@>D1 K<@D1-1@>D1, and k<@D2d@>D2=(4.08(]SY.+-.[)0.08)x10<@D15@>D1(25ﾟC), DELTAH<@D1(]SY.Thermod.[)@>D1=4.79(]SY.+-.[)0.10 kJ mol<@D1-1@>D1, DELTAS<@D1(]SY.Thermod.[)@>D1=4.79(]SY.+-.[)0.10 J mol<@D1-1@>D1 K<@D1-1@>D1. The rate constant is 10000 times smaller than that of the protanation of fluoride ion. The results suggest existence of a pre-equilibrium of a deformed sapphyrin structure to accept the fluoride ion. The rate constants for the formation and dissociation of zinc (II) complex were k<@D2f@>D2=(11.8(]SY.+-.[)0.2)x10<@D14@>D1(25ﾟC)mol<@D1-1@>D1 dm<@D13@>D1 s<@D1-1@>D1, DELTAH<@D1(]SY.Thermod.[)@>D1=82.0(]SY.+-.[)0.8 kJ mol<@D1-1@>D1, DELTAS<@D1(]SY.Thermod.[)@>D1=127(]SY.+-.[)3J mol<@D1-1@>D1 K<@D1-1@>D1, and k<@D2b@>D2=7.66(]SY.+-.[)0.71(25ﾟC), DELTAH<@D1(]SY.Thermod.[)@>D1=82.9(]SY.+-.[)6.5kJ mol<@D1-1@>D1, DELTAS<@D1(]SY.Thermod.[)@>D1=126(]SY.+-.[)22 J mol<@D1-1@>D1 K<@D1-1@>D1. The formation rate of zinc (II) complex is 1000 times as reactive as the zinc (II) porphyrin formation rate but is still smaller 100 times than the water dissociation from aqua zinc (II) ion.The fluoride ion-pair complex was extracted into chloroform and the chemical species is[H_4sap F^-]which also shows tfluoresence. Less