Supramolecular Self-assembly and Functionalization of Porphyrin-based Systems

Porphyrins are abundant in nature. They have been frequently employed as building blocks in the construction of nanoarchitectures and functional supramolecular systems. Recently, a series of novel porphyrin molecules including small molecules and polymers have been originally designed and synthesized with the aim of producing nanostructures with controllable-growth and materials with high-performance. Literature coverage is through 2004-2012. This review gives a full summary of related studies in our group.

Evolution of template-assisted two-dimensional porphyrin chiral grating structure by directed self-assembly using chiral second harmonic generation microscopy

Directed self-assembly has been used to create micro-nano scale patterns,including chiral periodic structures of organic molecules,for potential applications in optics,photonics,metamaterials,and medical and sensing technologies.This study presents a straightforward approach for fabricating large-scale chiral grating porphyrin assemblies through template-assisted techniques.The solution of tetrakis(4-sulfonatophenyl)porphyrin(TPPS)was induced by chiral amino acids(L/D-arginine and L/D-serine)to selfassemble into highly ordered chiral grating structures with the assistance of sodium dodecyl sulfate(SDS).The structures show precise line widths(5.5μm)and gaps(18μm).Using in situ optical microscopy and second harmonic generation(SHG)microscopy,the chiral characteristics and dynamic evolution of the template-assisted self-assembly are investigated.It is found that the chirality of amino acids induced TPPS self-assembled into chiral structures and the liquid contraction interface significantly enhanced the chirality of the assemblies.This study is significant for understanding the mechanism of chiral evolution and designing novel micro-nano materials with predetermined chiral properties.

Tunneling Electron Induced Fluorescence from Single Porphyrin Molecules Decoupled by Striped-Phase Octanethiol Self-assembled Monolayer

We investigate tunneling electron induced luminescence from isolated single porphyrin molecules that are decoupled by striped-phase self-assembled monolayer of octanethiol from the underneath Au（111） substrate. Intrinsic single-molecule electroluminescence has been realized by such decoupling at both bias polarities. The photon emission intensity acquired from the molecular lobe is found stronger than that from the molecular center. These re- sults provide useful information on the understanding of electroluminescent behavior and mechanism in molecular tunnel junctions.

Synthesis of a Benzenethiol-derivatized Porphyrin for Self-assembly

The synthesis of a benzenethiol-derivatized porphyrin for flat-lying self-assembly on gold substrates is described. Acetyl protected thiol is not stable enough in Pd-catalyzed reactions. While acrylate derivatives protected thiol group shows good tolerance in Pd-catalyzed borylations and Suzuki-Miyaura coupling reactions and no catalyst poisoning was observed.

Characterization of Formation Kinetics of Self-Assembled Thiol Monolayers on Gold by Electrochemical Impedance Spectroscopy

Self-assembled monolayers of octadecanethiol (ODT) on gold have been studied by electrochemical impedance spectroscopy (EIS). The fractional coverage has been examined as a function of immersion time of Au in ODT deposition solution. The fractional coverage exhibits two distinct adsorption steps: an initial rapid step followed by a slow one. The fractional coverage of ODT monolayer increases sharply from zero to more than 99% of its maximum within the first minute. However. it takes a day for the fractional coverage to approach its final value.

Self-assembly of porphyrins on perovskite film for blade-coating stable large-area methylammonium-free solar cells

Phase transition and phase separation of formamidinium-cesium(FA-Cs)perovskite during the fabrication and operation processes reduce the efficiency and stability of perovskite solar cells(PSCs).Here,we develop an in situ molecular self-assembly approach on perovskite surface using an amine nickel porphyrin(NiP).The NiP doped perovskite precursor solution was deposited on substrate by blade-coating under ambient condition.NiP molecules self-assemble into supramolecule bound on perovskite surface during the vacuum-assisted process.Such a modification controls the perovskite grain growth to generate the uniform perovskite film.The supramolecule can release the residual lattice strain to inhibit the phase transition of perovskite film,and promote the charge extraction and transport to suppress the phase separation of FA-Cs perovskite during long-term illumination condition.Consequently,the best efficiency of large-area NiP-based FA-Cs-PSCs with the active area of 1.0 cm2 is up to 20.3%(certified as 19.2%),which is close to the record efficiency(20.37%)by blade-coating.Unencapsulated NiP-doped device reveals the remarkably improved overall stabilities.This work affords a novel way to address the phase transition and phase separation in FA-Cs perovskite.

Lead and Iodide Fixation by Thiol Copper(Ⅱ)Porphyrin for Stable and Environmental-Friendly Perovskite Solar Cells

The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.

Characterization of self-assembled monolayers of porphyrins bearing multiple-thiol and photoelectric response

Self-assembled monolayers（SAMs） of thiol-derivatized porphyrin molecules on Au substrate have attracted extensively interest for use in sensing,optoelectronic devices and molecular electronics.In this paper,tetra-[p-（3-mercaptopropyloxy）-phenyl]porphyrin was synthesized and self-assembled with thiol on Au substrate for porphyrin SAMs（PPS 4）.The electrochemical results demonstrated that PPS 4 could form excellent SAMs on gold surface.Self-assembled nanojunctions of PPS 4 were fabricated by using gold nanogap electrodes（gap width：ca.100 nm）.With the light on/off,the nanojunctions showed current high/low as nanometer scaled photo switch.

Highly ordered arrangement of meso-tetrakis(4-aminophenyl)porphyrin in self-assembled nanoaggregates via hydrogen bonding

meso-Tetrakis（4-aminophenyl）porphyrin（TAPP） can self-assemble into nanostructures with different morphologies by a phase-transfer method.The morphologies（nanospheres,nanorods and nanothorns）of porphyrin nanoaggregates could be easily tuned just by changing the concentration of porphyrin in a proper solvent at room temperature.HRTEM images revealed the formation of highly ordered supramolecular arrays of TAPP,i.e. superlattice of TAPP molecules in nanoaggregates,which agreed well with the size of one molecule of TAPP.UV–vis absorption spectra showed an obvious red shift of the Soret band of TAPP,indicating the formation of J-aggregates of TAPP in nanoaggregates.

Chiral porphyrin assemblies

Porphyrins are among the most important macrocycles because they perform many essential functions in living systems and serve as building blocks in many functional materials.Incorporating the chirality into porphyrins can aid biomimetic research and the exploration of new functional materials.In this review,recent developments in chiral porphyrin assemblies are highlighted.The review is mainly divided into two sections:the different strategies for constructing chiral porphyrin assemblies and the applications.The formation of chiral porphyrin assemblies can be from porphyrin molecules substituted with chiral groups;achiral porphyrins induced by chiral additives and spontaneous deracemizations of achiral porphyrins during the assemblies.We also provide an overview of the applications of chiral porphyrin assemblies in chiral sensing,asymmetry catalysis,circularly polarized luminescence,and so on.The further challenge in the field is discussed.

Morphology-controlled porphyrin nanocrystals with enhanced photocatalytic hydrogen production

Molecular self-assembly is a natured-inspired strategy to integrate individual functional molecules into supramolecular nanostructured materials through noncovalent bond interactions for solar to fuel conversion.However,the design and engineering of the morphology,size,and orderly stacking of supramolecular nanostructures remain a great challenge.In this study,regular porphyrin nanocrystals with different orderly stacked structures are synthesized through noncovalent self-assembly of Pt(II)meso-tetra(4-carboxyphenyl)porphine(PtTCPP),using surfactants with different electronegativity.The synergy of noncovalent bond interactions between porphyrin molecules,and between porphyrin molecules and surfactants resulted in different molecular packing patterns.Due to the spatial ordering of PtTCPP molecules,the different nanocrystals exhibit both collective optical properties and morphology-dependent activities in photocatalytic hydrogen production.The measurements of the photodeposition of dual cocatalysts showed that the photogenerated electrons and holes selectively aggregated at different active sites,revealing separation pathways and directional transfer of photogenerated electrons and holes in the assemblies.This study provides a new strategy to exert rational control over porphyrin self-assembly nanocrystals for highly efficient water splitting.

Hybrid supraparticles of carbon dots/porphyrin for multifunctional tongue-mimic sensors

Supraparticles(SPs),such as assembly of inorganic components with organic,have made tremendous attention in biochemical analysis,which represents a novel but challenging research orientation.Herein,a single-SPs multifunctional fluorescent sensor array has been developed for high-throughput detection of heavy metal ions in biofluids,which is based on an inorganic/organic hybrid SPs consisting of carbon dots(CDs)and an easily available porphyrin[5,10,15,20-tetra(4-carboxyphenyl)porphyrin(TCPP)].TCPP can aggregate with the CDs to form the assembly(CDs/TCPP SPs)through the electrostatic andπ-πstacking interaction.There are two independent and clearly separated fluorescence emission peaks at 470 and 668 nm in the resultant CDs/TCPP SPs under 380 nm excitation.As a proof-of concept design,F 470,F 668,F 668/F 470 of SPs are chosen as three sensor components to constitute our sensor array.With the addi-tion of metal ions,three sensor components can generate different fluorescence response patterns for discriminating 11 heavy metal ions via principal component analysis(PCA).Additionally,thiols can read-ily capture Cu^(2+)to switch the fluorescence of CDs/TCPP initially altered by Cu^(2+).Hence,CDs/TCPP-Cu^(2+)ensemble is further demonstrated to be a powerful sensor array for pattern recognition of 7 thiols and even chiral recognition of cysteine enantiomers.This novel strategy avoids the tanglesome synthesis of multiple sensing probes and dedicates an innovative method for the facile establishment of tongue-mimic sensors,which would prospectively sprout more homologous assumptions to broaden its application toward more biosensing fields.

Nonlinear Optical Properties of Porphyrin Derivatives with Electron-donating or Electron-withdrawing Substituents

To investigate photoelectric properties of meso-extended porphyrin derivatives with electron-donating or elec- tron-withdrawing substituents, a series of functionalized porphyrin materials have been designed and synthesized by Suzuki coupling reaction. The meso-extended structures were fully characterized by IH NMR, IR spectroscopy and mass spectrometry. The photophysical properties of porphyrin derivatives were carefully examined by UV-Visible and fluorescence spectra, and the solvatochromic effect was observed and discussed. In particular, Z-scan technique was employed to characterize the third-order nonlinear optical （NLO） properties of the products such as nonlinear absorption and refraction, the third-order nonlinear refractive indexes （x（3）-value） of these porphyrin derivatives achieved 3.9 × 10-12 esu. In addition, the compounds could be self-assembled into highly organized morphologies through phase-exchange method. All the results indicated that the discotic materials have the potential for optoelec- tronic applications.

系列卟啉化合物的合成及其光谱和电化学性质研究

合成了系列羟基苯基和系列巯基苯基卟啉,并应用紫外光谱、荧光光谱及其电化学方法定性研究了其性质与结构间的关系。

巯基卟啉自组装膜的制备及应用研究进展

详细介绍了巯基卟啉自组装膜的几种制备方法,评述了不同制备方法的优缺点;对卟啉自组装膜在电荷转移、分子氧电催化、分子光电器件等领域的研究进展进行了评述,引用文献54篇。

一类巯基衍生卟啉的合成及其电化学性质研究

以香草醛、苯甲醛和吡咯为起始原料合成了3种新型尾式巯基卟啉和相应的钴卟啉,用IR、UV-Vis和1HNMR进行了表征.将巯基衍生卟啉自组装在金电极表面,用电化学方法研究了自由碱卟啉和金属卟啉自组膜性质的差异.

不同类型卟啉自组装膜的制备及表征

制备了不同类型的巯基卟啉自组装膜,借助多种表征技术(紫外可见光谱、电化学和X射线光电子能谱)研究了不同类型卟啉自组装膜的结构特点;研究结果表明,卟啉分子中巯基取代基数目的不同(—[SH]n—,n=1,4),导致了卟啉环在自组装膜表面的构型不同,从而表现出不同巯基卟啉自组装膜性能的差异。在此基础上,提出了不同巯基卟啉自组装膜的结构模型。

系列巯基苯基卟啉自组装膜的光谱和电化学性质

考察了系列巯基苯基卟啉自组装膜的光谱及电化学特征。结果表明,与溶液中巯基苯基卟啉的光谱相比,自组装膜中卟啉分子的吸收和荧光光谱均发生了明显变化,随着卟啉分子中巯基数目的增加,其荧光峰依次发生红移;不同巯基苯基卟啉自组装膜修饰电极对电解液中电对的电子转移阻碍能力不同,由5,10-二[4-(3-巯基丙氧基)-苯基]-15,20二苯基卟啉形成的卟啉自组装膜的阻碍作用最强,膜表面覆盖度最致密。

巯基苯基卟啉自组装膜的制备及其光电性质

合成了四巯基苯基卟啉并用紫外光谱、红外光谱及核磁共振进行了表征.用紫外光谱、电化学方法和光电子能谱对形成的卟啉自组装膜进行了研究.结果表明,将四巯基苯基卟啉修饰在纳米间隙电极上后,形成的卟啉纳米结具有较好的光伏特性,在可见光照射下,纳米结表现出良好的开关效应.

Spiral fractal patterns via hierarchical assembly

Chirality is ubiquitous in nature and manifested at various scale from subatom to galaxy.Fractal geometry is also very popular and active in the world.However,there are few reports on the concept of combining fractal patterns and chiral structures in self-assembled systems.It was found that tree-shaped fractal patterns could be self-assembled from the N-[(9H-fluoren-9-ylmethoxy)carbonyl]protected glutamic acid(Fmoc-Glu)and zinc-porphyrin(ZnTPyP).The fractal pattern was composed of nanorod aggregate arranged in a spiral fractal way,in which the nanorods were stacked one-by-one in a single direction.The patterns started with the formation of initial nucleon and growing,during which the diffusion limited aggregation(DLA)mechanism led to the fractal patterns.Interestingly,the spiral packing and their branches were closely related to the absolute configuration of Fmoc-Glu that anticlockwise and clockwise arrangement for L-Fmoc-Glu/ZnTPyP and D-Fmoc-Glu/ZnTPyP,respectively.Our work provides a new finding on the spiral fractal pattern via hierarchical self-assembly.