Variation of formal hydrogen-bonding networks within electronically delocalized π-conjugated oligopeptide nanostructures.
Variation of formal hydrogen-bonding networks within electronically delocalized π-conjugated oligopeptide nanostructures.
复制标题
电子离域π-共轭寡肽纳米结构内正式氢键网络的变化。
作者：
Brian D. Wall;Yuecheng Zhou;Shao Mei;H. A. Ardoña;Andrew L. Ferguson;J. Tovar
这一光物理研究表征了纳米材料中分子间电子相互作用的普遍性，这些纳米材料是由嵌入π共轭低聚苯乙烯（OPV）亚基（二苯乙烯和二苯基苯）的自组装寡肽衍生的，原则上呈现两种不同的β-片基序。两种不同的合成方法导致寡肽在自组装后被期望自组装成由β-片状二级结构稳定的多聚体聚集体。目标分子表达两个连接到中心OPV核心的c端（对称肽）或更常见的天然寡肽（非对称肽）的n端到c端极性。两种肽二级结构均形成扩展的一维肽聚集体，分子间π-电子相互作用密切。π共轭OPV段长度的不同导致了分子间相互作用程度的不同以及由此产生的光物理现象。含有较短的二苯乙烯（OPV2）基的多肽基态相互作用较小，产生准分子发射；而含有较长的二苯基苯（OPV3）基的多肽基态相互作用不同，导致激子耦合或准分子激发态引起电子性质的扰动。新生聚集体形成的分子动力学模拟预测肽二聚化是一个自发过程，对所考虑的四种分子具有2-6 kcal/mol的热力学驱动势。在热力学上，含有OPV3亚基的肽的反平行排列比平行排列更有利，而对于含有OPV2亚基的肽，这两种排列同样有利。本研究验证了肽-π-肽自组装的通用性，提供了电子离域的超分子结构，并提出了肽序列设计的灵活性，作为调整π共轭超分子聚合物材料性质的一种方法。
This photophysical study characterizes the generality of intermolecular electronic interactions present within nanomaterials derived from self-assembling oligopeptides with embedded π-conjugated oligophenylenevinylene (OPV) subunits stilbene and distyrylbenzene that in principle present two distinct β-sheet motifs. Two different synthetic approaches led to oligopeptides that upon self-assembly are expected to self-assemble into multimeric aggregates stabilized by β-sheet-like secondary structures. The target molecules express either two C-termini linked to the central OPV core (symmetric peptides) or the more common N-termini to C-termini polarity typical of natural oligopeptides (nonsymmetric peptides). Both peptide secondary structures were shown to form extended 1-D peptide aggregates with intimate intermolecular π-electron interactions. Differences in length of the π-conjugated OPV segments resulted in differing extents of intermolecular interactions and the resulting photophysics. The peptides containing the shorter stilbene (OPV2) units showed little ground state interactions and resulted in excimeric emission, while the longer distyrylbenzene (OPV3) peptides had different ground state interactions between adjacent π-conjugated subunits resulting in either perturbed electronic properties arising from exciton coupling or excimer-like excited states. Molecular dynamics simulations of nascent aggregate formation predict peptide dimerization to be a spontaneous process, possessing thermodynamic driving potentials in the range 2-6 kcal/mol for the four molecules considered. Antiparallel stacking of the peptides containing an OPV3 subunit is thermodynamically favored over the parallel orientation, whereas both arrangements are equally favored for the peptides containing an OPV2 subunit. This study validates the generality of peptide-π-peptide self-assembly to provide electronically delocalized supramolecular structures and suggests flexibility in peptide sequence design as a way to tune the material properties of π-conjugated supramolecular polymers.
影响因子：
32.4
作者：
Ferguson AL;Mann JK;Omarjee S;Ndung'u T;Walker BD;Chakraborty AK
通讯作者：
Chakraborty AK
影响因子：
56.9
作者：
Schmitz, JE;Kuroda, MJ;Reimann, KA
通讯作者：
Reimann, KA
影响因子：
32.4
作者：
McElrath MJ;Haynes BF
通讯作者：
Haynes BF