Bifunctional coordinating polymers: Auxiliary groups as a means of tuning the ionic affinity of immobilized phosphate ligands
Bifunctional coordinating polymers: Auxiliary groups as a means of tuning the ionic affinity of immobilized phosphate ligands
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DOI：
10.1021/ma050057b
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发表时间：
2005-07-12
期刊：
影响因子：
5.5
通讯作者：
Zhu, XP
中科院分区：
文献类型：
--
作者：
Alexandratos, SD;Zhu, XP
将多元醇(乙二醇、甘油、1，1，1-三羟甲基乙烷、季戊四醇和季戊四醇三乙氧基酸酯)固定在交联的聚氯乙烯上，然后用磷酸二乙酯进行单取代，合成了一系列配位聚合物。用一系列二价过渡金属离子：Pb2+、Cd2+、Cu2+、Ni2+和Zn2+测定离子亲和力。对于每个聚合物，控制亲和力的变量由分配系数D测量，是过渡金属离子的极化率，由Misono软度参数a测量。对于D2：0，相关性为D=S sigma+sigma(Min)，其中S是选择性，sigma(Min)是二价过渡金属离子的最小软度，必须超过它才能发生配位。S的值为3810(季戊四醇)、1480(季戊四醇三乙氧基)、1340(甘油)、474(三羟甲基)乙烷和21(乙二醇)；S增加表示更大的选择性。有人认为，虽然通过磷酸配体发生配位，但选择性随着多元醇的变化而变化：-OH基团作为辅助基团通过氢键改变磷酸配体(初级配体)的极化率，从而影响初级配体的选择性。在聚合物的FTIR光谱中，在874-895 cm(-1)的吸收范围内有明显的-OH和磷酸部分之间的相互作用。
A series of coordinating polymers are synthesized by immobilizing polyols (ethylene glycol, glycerol, 1, 1, 1-tris(hydroxymethyl)ethane, pentaerythritol, and pentaerythritol triethoxylate) onto crosslinked poly(vinylbenzyl chloride) and then monosubstituting with diethyl phosphate ligands. Ionic affinities are determined with a series of divalent transition metal ions: Pb2+, Cd2+, CU2+, Ni2+, and Zn2+. For each polymer, the variable controlling the affinity, as measured by the distribution coefficient, D, is the polarizability of the transition metal ion, as measured by the Misono softness parameter, a. For D 2: 0, the correlation is D = S sigma + sigma(min), where S is the selectivity and sigma(min) is the minimum softness of a divalent transition metal ion which must be exceeded for coordination to occur. The values of S are 3810 (pentaerythritol), 1480 (pentaerythritol triethoxylate), 1340 (glycerol), 474 (tris(hydroxymethyl)ethane), and 21 (glycol); increasing S indicates greater selectivity. It is proposed that, though coordination occurs through the phosphate ligand, selectivity varies as a function of the polyol: the -OH groups act as auxiliary groups in modifying the polarizability of the phosphate ligands (the primary ligand) through hydrogen bonding and, as a result, affecting the selectivity of the primary ligand. Interaction between the -OH and phosphate moieties is evident in FTIR spectra of the polymers with the absorbance of a band within the range 874-895 cm(-1).