Formation and Mechanism of Alkali Metal Porphyrins and their Application to Analytical Chemistry

水溶性卟啉(2,3.7,8,12,13,17,18-八溴-5,10,15,20-四基（4-磺酰基）卟啉；H < @D22@ > D2obtpps < @D14 @ > D1;合成了H2P<@D14-@>D1)，用于水溶液中锂离子的测定和分离。八溴基通过其吸电子作用降低了卟啉的碱度，使卟啉在碱性水溶液中与锂离子反应形成锂配合物，并伴有吸收最大值的移位；lmax （log epsilon/mol<@D1-1@>D1 dm<@D13@>D1 cm<@D1-1@>D1）分别为490.5 nm（5.31）和734 nm（4.36）。钠离子和钾离子不与卟啉反应。在pH l3下，Li<@D1+@>D1+HP<@ d15 -@>D1 [LiP]<@ d15 -@>D1+H<@D1+@>D1的平衡常数为10-8.81,[LiP]<@ d15 -@>D1的条件生成常数为10<@ d14.21 @>D1。[LiP]<@ d15 -@>D1可与四uthylammonium离子（X<@D1+@>D1）形成离子对配合物，提取得到的X<@ d25 @>D2LiP解离为X<@ d24 @>D2LiP<@D1-@>D1和X<@D1+@>D1。[LiP<@ d15 @>D1-]<@ d2a @>D2+5[X<@D1+@>D1]<@ d20 @>D2(]SY.dblharw. dblharw。[)[X<@D24@>D2LiP<@D1-@>D1]<@D20@>D2+[X<@D1-@>D1]<@D20@>D2 = (8.4(]SY.+- . [)0.7) × 10<@D112@>D1 mol<@D1-4@>D1 dm<@D112@>D1，其中下标a和o分别表示水相和有机相中的化学物质。上述结果适用于血清、海水和温泉水样品中锂的测定，范围为0.07 ~ 0.7 mg dm<@D1-3@>D1 （1 × 10<@D1-5@>D1-1 × 10<@D1-4@>D1 mol dm<@D1-3@>D1）。如果样品中含有镁（II）离子，则以N，N'-1,2-乙二基双-[N（羧甲基）-甘氨酸]镁（II） ([Mg (edta)]<@D12-@>D1或H<@D24@>D2 edta干扰重金属离子。

A water-soluble porphyrin (2,3.7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin ; H<@D22@>D2obtpps<@D14-@>D1 ; H2P<@D14-@>D1) was synthesized and develped for the determination and separation of lithium ion in aqueous solution. Tne octabromo groups lower the basicity of the porphyrin by their eletron-withdrawing effect and enable the porphyrin to react with lithium ion in alkaline aqueous solution to form the lithium complex along with a shft of absorption maxima ; lmax (log epsilon/mol<@D1-1@>D1 dm<@D13@>D1 cm<@D1-1@>D1) of thg lithium porphyrin are 490.5 nm (5.31) and 734 nm (4.36). Sodium and potassium ions did not react with the porphyrin. The equilibrium constant for the reaction Li<@D1+@>D1+HP<@D15-@>D1 [LiP]<@D15-@>D1+H<@D1+@>D1 was found to be 10-8.81 and the condtional formation constant ofthe [LiP]<@D15-@>D1 at pH l3 is10<@D14.21@>D1.The [LiP]<@D15-@>D1 can be extracted into chloroform as an ion-pair complex with tetracuthylammonium ion (X<@D1+@>D1) and the extracted X<@D25@>D2LiP dissociates to X<@D24@>D2LiP<@D1-@>D1 and X<@D1+@>D1 in chlomform. The exttraction constant for the reaction of [LiP<@D15@>D1-]<@D2a@>D2+5[X<@D1+@>D1]<@D20@>D2(]SY.dblharw.[)[X<@D24@>D2LiP<@D1-@>D1]<@D20@>D2+[X<@D1-@>D1]<@D20@>D2 was found to be (8.4(]SY.+-。[)0.7) x 10<@D112@>D1 mol<@D1-4@>D1 dm<@D112@>D1, where subscripts of a and o denote chemical species in aqueous and organic phases, respectively. The above results were developed for the determination of lithium in serum, sea water and hot-spring water samples at a range of 0.07-0.7 mg dm<@D1-3@>D1 (1 x 10<@D1-5@>D1-1 x 10<@D1-4@>D1 mol dm<@D1-3@>D1). The interference of hevy metal ions was by N,N'-1,2-ethanediylbis-[N (carboxylmethyl)-glycinato] magnesium (II) ([Mg (edta)]<@D12-@>D1 or H<@D24@>D2 edta if sample contain magnesium (II) ion.