Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina and C.I.R.C.M.S.B. V.le F. Stagno D'Alcontres, 31-98166 Messina, Italy.
CNR-ISMN Istituto per lo Studio dei Materiali Nanostrutturati c/o Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina, V.le F. Stagno D'Alcontres, 31-98166 Messina, Italy.
Molecules. 2020 Dec 5;25(23):5742. doi: 10.3390/molecules25235742.
Under mild acidic conditions, various metal derivatives of tetrakis(4--methylpyridinium)porphyrin (gold(III), AuT; cobalt(III), CoT; manganese(III), MnT and zinc(II), ZnT) catalytically promote the supramolecular assembling process of the diacid 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (HTPPS) into J-aggregates. The aggregation kinetics have been treated according to a well-established model that involves the initial formation of a critical nucleus containing porphyrin units, followed by autocatalytic growth, in which the rate evolves as a power of time. An analysis of the extinction time traces allows to obtain the rate constants for the auto-catalyzed pathway, , and the number of porphyrins involved in the initial seeding. The aggregation kinetics have been investigated at fixed HTPPS concentration as a function of the added metal derivatives MT. The derived rate constants, , obey a rate law that is first order in [MT] and depend on the specific nature of the catalyst in the order AuT > CoT > MnT > ZnT. Both resonance light scattering (RLS) intensity and extinction in the aggregated samples increase on increasing [MT]. With the exception of AuT, the final aggregated samples obtained at the highest catalyst concentration exhibit a negative Cotton effect in the J-band region, evidencing the occurrence of spontaneous symmetry breaking. The role of the nature of the metal derivative in terms of overall charge and presence of axial groups will be discussed.
在弱酸条件下，四（4--甲基吡啶基）卟啉的各种金属衍生物（金（III），AuT；钴（III），CoT；锰（III），MnT 和锌（II），ZnT）催化促进二酸 5,10,15,20-四（4-磺酸钠基苯基）卟啉（HTPPS）的超分子组装过程形成 J-聚集体。聚合动力学根据一个成熟的模型进行处理，该模型涉及包含卟啉单元的临界核的初始形成，然后是自动催化生长，其中速率随时间的幂次变化。对消光时间迹线的分析可以获得自动催化途径的速率常数，和参与初始播种的卟啉数量。聚合动力学在固定 HTPPS 浓度下作为添加的金属衍生物 MT 的函数进行研究。得到的速率常数，服从[MT]的一级速率定律，并取决于催化剂的特定性质，其顺序为 AuT > CoT > MnT > ZnT。随着[MT]的增加，聚集样品的共振光散射（RLS）强度和消光都会增加。除了 AuT 之外，在最高催化剂浓度下获得的最终聚集样品在 J-带区域表现出负的 Cotton 效应，证明自发对称破缺的发生。将讨论金属衍生物的性质在总电荷和轴向基团存在方面的作用。
