FERRIC ION SEQUESTERING AGENTS .13. SYNTHESIS, STRUCTURES, AND THERMODYNAMICS OF COMPLEXATION OF COBALT(III) AND IRON(III) TRIS COMPLEXES OF SEVERAL CHELATING HYDROXYPYRIDINONES
FERRIC ION SEQUESTERING AGENTS .13. SYNTHESIS, STRUCTURES, AND THERMODYNAMICS OF COMPLEXATION OF COBALT(III) AND IRON(III) TRIS COMPLEXES OF SEVERAL CHELATING HYDROXYPYRIDINONES
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DOI：
10.1021/ic00200a030
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发表时间：
1985-01-01
影响因子：
4.6
通讯作者：
RAYMOND, KN
中科院分区：
文献类型：
--
作者：
SCARROW, RC;RILEY, PE;RAYMOND, KN
本文报道了双齿羟基吡啶酮金属配合物的制备和表征。用X射线单晶衍射法对1-羟基-2（1/f）-吡啶酮（1，2-opo）的Co（Ⅲ）、Fe（Ⅲ）三配合物和3-羟基-2（1/f）-吡啶酮（3，2-opo）的Fe（Ⅲ）三配合物进行了表征。变温NMR表明，钴配合物是构象不稳定的CDC13。通过分光光度滴定法测定了几种螯合羟基吡啶酮单阴离子的Fe（III）络合物的形成常数，表明这些配体具有介于单阴离子异羟肟酸盐和双阴离子儿茶酚盐之间的螯合亲合力forFe（III）。羟基吡啶酮的相对强的酸性（pKa = 5 - 9）使它们在中性或酸性溶液中比邻苯二酚或异羟肟酸盐更有效地螯合铁离子。所有金属配合物的晶体结构相对于双齿OPO配体中的氮的位置是无序的。两种结构相似的深绿色Co观察到（1，2-OPO）3晶体;一种是P2 xjn，a = 9.702（2）A，B = 9.516（2）A，c = 17.146（3）A，ε = 103.41（1），Z = 4;另一种是C2/c，a = 15.142（2）A，B = 9.507（1）A，c = 10.845（1）A，λ = 96.00（1），Z = 4。全矩阵最小二乘细化（启用|F|在F02> 30（F02）的情况下，使用2589和882次反射，分别以R = 0.063和0.024以及Rw = 0.071和0.031收敛。Fe（III）与1，2-opo和3，2-opo异构体的三络合物的晶体在空间群R3c中形成。Fe（1，2-opo）3配合物结晶为黄橙色的parellelepipeds，其中a = B = 9.634（1）A，c = 31.290（5）A（六方晶系），Z = 6。使用FJ> 3a（F2）的556个反射的精细化收敛到R = 0.021和J？w = 0.035。Fe（3，2-opo）3配合物为橙子片状，a = B = 9.782（1）A，c = 29.615（3）A，Z = 6.使用F2> 3a（F2）的629个观测值的精化收敛到R = 0.024和J？w = 0.035。未配位的7 V，A-二甲基-1-羟基-2-（1/f）-吡啶酮-6-甲酰胺为黄白色针状物，空间群P2/n，a = 18.803（2）A，B = 9.274（1）A，c = 4.969（1）A，c = 96.10（1），Z = 4。使用F2> 3a（F2）的1183次反射进行细化，收敛到R = 0.041和Rw = 0.061。
Metal complexes of bidentate hydroxypyridinone ligands havebeen prepared and characterized. The pseudooctahedral Co (III) and Fe (III) tris complexes of 1-hydroxy-2 (l/f)-pyridinonate (1, 2-opo) and the Fe (III) tris complex of 3-hydroxy-2 (l//)-pyridinonate (3, 2-opo) have been characterized by single-crystal X-ray diffraction. Variable-temperature NMR shows the cobalt complex is conformationally labile in CDC13. Determination of the formation constants of the Fe (III) complexes of several chelating hydroxypyridinone monoanions by spectrophotometric titration demonstrates that these ligands have chelation affinities forFe (III) that are intermediate between those of monoanionic hydroxamate and dianionic catecholate species. The relatively strong acidities of the hydroxypyridinones (pKa’s= 5-9) enable them to chelate ferric ion more effectively than catechol or hydroxamates in neutral or acidic solutions. The crystal structures of all the metal complexes are disordered with respect to the location of the nitrogen in the bidentate opo ligands. Two structurally similar forms of dark green Co (l, 2-opo) 3 crystals were observed; one is P2xjn with a= 9.702 (2) A, b= 9.516 (2) A, c= 17.146 (3) A, ß= 103.41 (1), and Z= 4, and the other is C2/c with a= 15.142 (2) A, b= 9.507 (1) A, c= 10.845 (1) A, ß= 96.00 (1), and Z= 4. Full-matrix least-squares refinement (on| F|) using 2589 and 882 reflections with F02> 3o (F02) has converged with R= 0.063 and 0.024 and Rw= 0.071 and 0.031, respectively. Crystals of the tris complexes of Fe (III) with the 1, 2-opo and 3, 2-opo isomers form in space group R3c. The Fe (l, 2-opo) 3 complex crystallizes as yellow-orange parellelepipeds with a= b= 9.634 (1) A, c= 31.290 (5) A (hexagonal setting), and Z= 6. Refinement using556 reflections with FJ> 3a (F2) converged to R= 0.021 and J? w= 0.035. The Fe (3, 2-opo) 3 complex forms as orange plates with a= b= 9.782 (1) A, c= 29.615 (3) A, and Z= 6. Refinement using 629 observations with F2> 3a {F2) converged to R= 0.024 and J? w= 0.035. Yellow-white needles of the uncomplexed molecule 7V, A-dimethyl-1-hydroxy-2-(l/f)-pyridinone-6-carboxamide are of space group P2¡/n with a= 18.803 (2) A, b= 9.274 (1) A, c= 4.969 (1) A,¡ 3= 96.10 (1), and Z= 4. Refinement using 1183 reflections withF2> 3a (F2) converged to R= 0.041 and Rw= 0.061.