State Key Laboratory of Hollow Fiber Membrane Materials and Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, People's Republic of China.
Langmuir. 2013 Jul 16;29(28):8936-43. doi: 10.1021/la401805x. Epub 2013 Jul 1.
Aggregation of Fe(III)-tetra-(4-sulfonatophenyl)-porphyrin (Fe(III)TPPS) was studied in the presence of block copolymers, poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP), poly(ethylene glycol)-block-poly(2-(dimethylamino)ethyl methylacrylate) (PEG-b-PDMAEMA), and poly(ethylene glycol)-block-poly(β-cyclodextrin) (PEG-b-PCD). The interaction between the iron porphyrin and the blocks, P4VP, PDMAEMA, and PCD, led to the formation of copolymers/Fe(III)TPPS complex micelles with a PEG shell and determined the species of Fe(III)TPPS. The electrostatic interaction of protonated P4VP and PDMAEMA with Fe(III)TPPS remarkably decreased the apparent pKd of Fe(III)TPPS and led to a micellar μ-oxo dimer of the iron porphyrin. At pH above the pKa of P4VP, Fe(III)TPPS was kept inside the hydrophobic P4VP core and formed an encapsulated μ-oxo dimer. However, when above the pKa of PDMAEMA, Fe(III)TPPS escaped from the hydrophobic PDMAEMA core, existing as a free μ-oxo dimer. PCD caused the monomer of the porphyrin because of the inclusion complexation between the β-cyclodextrin residues and Fe(III)TPPS. The two micellar monomer species Fe(III)TPPS(H2O)2 and Fe(III)TPPS(OH) were obtained with an equilibrium pKa ~ 6.4.
在嵌段共聚物存在的情况下研究了 Fe(III)-四-(4-磺酸钠基苯基)卟啉（Fe(III)TPPS）的聚集，嵌段共聚物为聚乙二醇-聚(4-乙烯基吡啶)（PEG-b-P4VP）、聚乙二醇-聚(2-(二甲氨基)乙基甲基丙烯酸酯)（PEG-b-PDMAEMA）和聚乙二醇-聚(β-环糊精)（PEG-b-PCD）。铁卟啉与嵌段 P4VP、PDMAEMA 和 PCD 之间的相互作用导致形成具有 PEG 壳的共聚物/Fe(III)TPPS 复合胶束，并确定了 Fe(III)TPPS 的物种。质子化的 P4VP 和 PDMAEMA 与 Fe(III)TPPS 的静电相互作用显著降低了 Fe(III)TPPS 的表观 pKd，并导致铁卟啉的胶束 μ-氧合二聚体。在 pH 高于 P4VP 的 pKa 时，Fe(III)TPPS 被保留在疏水性 P4VP 核内并形成包封的 μ-氧合二聚体。然而，当 pH 高于 PDMAEMA 的 pKa 时，Fe(III)TPPS 从疏水性 PDMAEMA 核中逸出，以游离的 μ-氧合二聚体形式存在。PCD 引起卟啉单体，因为β-环糊精残基与 Fe(III)TPPS 之间存在包合络合。两种胶束单体物种 Fe(III)TPPS(H2O)2 和 Fe(III)TPPS(OH)通过平衡 pKa~6.4 获得。
