Diporphyrin tweezer for multichannel spectroscopic analysis of enantiomeric excess

Chiral 1,1’-binaphthyl-linked diporphyrin ‘tweezers’ (R)-1/(S)-1 and the corresponding zinc(II) complexes (R)-2/(S)-2 were prepared as chiral host molecules, and their utility for chiral analyses (especially enantiomeric excess (ee) determinations) were evaluated. Tris(1-n-dodecyl)porphyrins were used for the first time as the interacting units. Host capabilities of the diporphyrin tweezers were investigated by titrations with (R,R)- and (S,S)-cyclohexane-1,2-diamine (CHDA). The host molecules could be used as multichannel probes of ee by using UV-vis, circular dichroism (CD), fluorescence emission and ¹H nuclear magnetic resonance (¹H-NMR) methods. Chiral configurations could also be differentiated using CD or ¹H-NMR spectroscopy. All three optical techniques give good resolution of ee with reasonable sensitivity considering the low concentrations used (ca. 10⁻⁶ mol·L⁻¹). The ee determination of CHDA enantiomers using NMR spectroscopy is also possible because of the reasonably well separated resonances in the case of (R,R)- and (S,S)-CHDA. Non-metallated (R)-1/(S)-1 hosts could not be used to detect chiral information in a strongly acidic chiral guest. This work demonstrates the utility of 1,1’-binapthyl-linked chiral hosts for chiral analysis of ditopically interacting enantiomers.     

Porphyrin polymers and organic frameworks

The versatility of porphyrins as optoelectronic or catalytic units makes them attractive elements for inclusion in functional materials. Polymers that include porphyrins have been created with a wide variety of structures and used in a wide range of applications. This review covers recent developments in the synthesis, characterization and applications of polymeric materials in which porphyrins are key components of the repeat units, including the rapidly growing area of metal–organic frameworks and related covalent organic frameworks. © 2015 Society of Chemical Industry     

Visible photocatalytic activity and photoelectrochemical behavior of TiO2 nanoparticles modified with metal porphyrins containing hydroxyl group

TiO₂ nanoparticles modified with 5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin (HTPP), 5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin zinc (ZnHTPP) and trans-dichloro-5-(p-hydroxylphenyl)-10,15,20-triphenylporphyrin tin (SnHTPP) were prepared in order to improve the visible photocatalytic activity of TiO₂ nanoparticles. The photocatalytic activity of the modified TiO₂ nanoparticles was investigated by carrying out the photodegradation of methyl orange in aqueous solution under visible light irradiation. The TiO₂ nanoparticles modified with SnHTPP show the highest visible photocatalytic activity with a degradation ratio of 86% of methyl orange after 180 min irradiation among three catalysts. This result indicates that the central metal ions in porphyrins can significantly influence the sensitization efficiency of porphyrins. In addition, the photoelectrochemical behavior of the modified TiO₂ nanoparticles was examined and related to their photocatalytic activity. Finally, the photocatalytic mechanism was discussed preliminarily.     

金属卟啉在新型材料领域的应用进展

作为新型材料其中一员,卟啉及金属卟啉在光电器件、医药和功能材料等领域具有重要的研究意义和广泛的应用前景。本文综述了近年来卟啉及金属卟啉化合物在新型材料方面的研究,重点介绍了金属卟啉化合物在电化学、分子自组装及催化等方面的应用新进展,并对其未来在新型材料领域的研究进行了展望。     

金属酞菁/卟啉分子电催化CO2还原的研究进展

大气中日益增加的CO₂浓度导致了气候变化等环境问题。将CO₂催化转化为有价值的化学品具有重要意义。利用太阳能、风能等可再生能源产生的电能,通过电化学方法将CO₂还原转化为有价值的碳基化合物是最具有应用前景的方式。分子催化剂具有明确的结构和清晰的活性位点,可实现基于机理的性能优化。综述了近年来金属酞菁/卟啉分子在电催化CO₂还原为CO的实验和理论方面的最新研究进展。首先,介绍了金属酞菁/卟啉分子电催化CO₂还原为CO的详细机理。然后,重点介绍了如何通过分子分散和配体修饰提升金属酞菁/卟啉分子电催化CO₂还原为CO的活性和选择性。最后,讨论了金属酞菁/卟啉分子电催化CO₂还原存在的挑战及其可能的解决方案。     

A Blue Photosensitizer Realizing Efficient and Stable Green Solar Cells via Color Tuning by the Electrolyte

Semitransparent dye-sensitized solar cells (DSCs) are appealing as aesthetically pleasing and colorful see-through photovoltaics. Green semitransparent DSCs have been presented, but the best ones rely on green zinc porphyrin photosensitizers and high volatile electrolytes. For potential outdoor applications, the zinc porphyrin DSCs employing ionic liquid electrolytes merely reached a power conversion efficiency (PCE) of 6.3% even with opaque mesoporous TiO₂ films. Herein, the new green DSC is realized by using a blue organic photosensitizer in conjunction with an orange ionic-liquid-based electrolyte, presenting a simple and an effective path for color tuning of photovoltaics. The new approach allows for broadly modulating the color from spring green to cyan by tuning the contributions of the light absorption by the dye-sensitized TiO₂ film and the electrolyte layer. The new semitransparent DSCs with spring green to cyan colors have PCEs ranging from 6.7% to 8.1% and show stability for 1000 h under accelerated ageing test at 80 °C, superior to the zinc porphyrin DSCs. The findings pave a new way to achieve efficient and stable colorful solar cells.     

Efficient Electron Transfer Processes and Enhanced Electrocatalytic Activity of Cobalt(II) Porphyrin Anchored on Graphene Oxide

We investigated the electronic perturbation between graphene oxide and cobalt porphyrin to reveal the origin of the enhanced electrocatalytic activity of a hybrid complex using time-resolved spectroscopic measurements and theoretical calculations. The impulsively generated charge-separated state, GO⁻-(Co^IIAPFP)⁺, undergoes fast charge recombination (<10 ps) between GO⁻ and (Co^IIAPFP)⁺ moieties. This fast charge recombination is directly related to the quick neutralization of (Co^IIAPFP)⁺, which shortens the dead time of inactive Co^IIIAPFP after the electrocatalytic reduction reaction. The fast transformation of inactive Co^IIIAPFP to active Co^IIAPFP is an important factor in the enhanced electrocatalytic activity of the hybrid complex.     

A novel self-assembly with two acetohydrazide zinc porphyrins coordination polymer for supramolecular solar cells

Two new acetohydrazide zinc porphyrin with different donor units based Mn (Ⅱ) ion coordination polymers (CPsx, x=1,2) have been designed, synthesized, and well-characterized. Two coordination polymers and anchor porphyrin (ZnPA) self-assembly by metal-ligand axial coordination to modify the nano-structured TiO₂ electrode surface has been investigated in photoelectrochemical device. Our results reveal that the self-assemblies devices show significantly improved photocurrent conversion efficiency. Particularly, CPs1 based solar cell showed higher short circuit current density and conversion efficiency. Their optical performance, electrochemical impedance spectroscopy and transient photovoltage decay were also investigated to further understand the photoelectrochemical results. In addition, the assembled modes of the assemblies immobilized on TiO₂ electrode surfaces were also verified by transmission electron microscopy (TEM), theory calculations and energy dispersive X-ray spectroscopy (EDX).     

基于卟啉传感器的三聚氰胺检测研究

针对传统三聚氰胺检测方法成本高、分析时间长等不足之处,根据卟啉阵列与液体中分子或离子结合产生光谱变化的基本原理,设计了一种基于卟啉化学传感器的三聚氰胺检测系统.针对系统的软硬件设计,研究了光谱信号、模式识别、通过图像处理获得目标物质的特征信息,经过匹配识别,从而实现目标物质的检测.结合实例,运用该装置对牛奶中三聚氰胺进...     

Meso-取代卟啉及其金属配合物的合成进展

为了筛选仿生催化氧化环己烷的催化剂,通过查阅相关文献,重点概述了Meso-取代卟啉及其金属配合物的合成方法。合成卟啉的方法有Rothemund法、Adler法及其改进法、Lindsey法等,合成金属卟啉的方法有＂一步法＂和：＂两步法＂,目前,＂两步法＂被普遍使用。