Bioinspired porphyrin-peptide supramolecular assemblies and their applications

Inspired by the hierarchical chiral assembly of porphyrin-proteins in photosynthetic systems, the hierarchical self-assembly of porphyrin-amino acids/peptides provides a novel strategy for constructing functional materials. How to artificially simulate the assembly of porphyrins, proteins, and other cofactors in the photosynthesis system to obtain persistent strong light capture, charge separation and catalytic reactions has become an important concern in the construction of biomimetic photosynthesis systems. This paper summarizes the different assembly strategies adopted in recent years, the effects of driving forces on self-assembly, and the application of porphyrin-peptides in catalysis and biomedicine, and briefly discusses the challenges and prospects for future research.

Synthesis, Structure, and Properties of Palladium(II) Complex of α-Formyl Pyrrolyl Dipyrromethene

A simple α-formyl pyrrolyl dipyrromethene ligand was synthesized by deboronation of BF2-complex of α-formyl pyrrolyl dipyrrin under Lewis acid-catalyzed conditions. The α-formyl pyrrolyl dipyrrin ligand was treated with PdCl2 in...

Chirogenesis in Zinc Porphyrins: Theoretical Evaluation of Electronic Transitions, Controlling Structural Factors and Axial Ligation

In the present work, sixteen different zinc porphyrins (possessing different meso substituents) with and without a chiral guest were modelled using DFT and TD-DFT approaches in order to understand the influence of various controlling factors on electronic circular dichroism (ECD) spectra. Two major aspects are influenced by these factors: excitation energy of the electronic transitions and their intensity. In the case of excitation energy, the influence increases in the following order: orientation of the peripheral substituents Collapse

Key Words

• circular dichroism
• density functional calculations
• porphyrins
• supramolecular chemistry
• transition metals

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MESH Headings Collapse

Grants

• PUTJD749 Estonian Research Council
• PRG399 Estonian Research Council
• 828779 European Union's H2020-FETOPEN
• Estonian Research Council

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Affiliation(s)

Irina Osadchuk Department of Chemistry and BiotechnologySchool of ScienceTallinn University of Technology AddressAkadeemia tee 1512618TallinnEstonia ICGMUniv MontpellierCNRS, ENSCMMontpellierFrance
Riina Aav Department of Chemistry and BiotechnologySchool of ScienceTallinn University of Technology AddressAkadeemia tee 1512618TallinnEstonia
Victor Borovkov Department of Chemistry and BiotechnologySchool of ScienceTallinn University of Technology AddressAkadeemia tee 1512618TallinnEstonia
Eric Clot ICGMUniv MontpellierCNRS, ENSCMMontpellierFrance

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Nanoscale integration of porphyrin in GroEL protein cage: Photophysical and photochemical investigation

In this paper, we introduce a new type of functional, supramolecular porphyrin conjugate created using the bacterial GroEL protein cage based on non-specific hydrophobic interaction. The synthesis, structure and property of the porphyrin conjugate were characterized by dynamic light scattering, UV-vis spectroscopy and fluorescence spectroscopy. We observed that the model zinc-tetraphenylporphyrin (Zn-TPP) with high hydrophobicity can be well-dispersed in aqueous solutions with the aid of GroEL open chamber, which is known to be a favorable nanocompartment for aggregation-prone molecules. The maximal encapsulation efficiency of Zn-TPP in GroEL was determined to be ~98%. It is further seen that the constructed double Zn-TPP-GroEL complex exhibited good photocatalytic activity in the model reactions of the production of singlet oxygen and the reduction of methyl viologen under illumination with visible light. Moreover, we found that GroEL can significantly improve the photostability of Zn-TPP molecules as a result of nanoscale assembly within its hydrophobic chamber. Hence enhanced water solubility and photostability of Zn-TPP, which are considered as the first two hurdles for the wide usage of porphyrins, were achieved simultaneously by the development of GroEL cage as a building block. Supramolecular nanostructures formed from porphyrins (or related molecules) and GroEL for photocatalysis would greatly simplify applications of such structures.

Recent Progress with Pincer Transition Metal Catalysts for Sustainability

Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has the potential to play a fundamental role in this process, providing novel, efficient, and at the same time eco-friendly routes for both chemicals and energy production. In particular, pincer-type ligation shows promising properties in terms of long-term stability and selectivity, as well as allowing for mild reaction conditions and low catalyst loading. Indeed, pincer complexes have been applied to a plethora of sustainable chemical processes, such as hydrogen release, CO2 capture and conversion, N2 fixation, and biomass valorization for the synthesis of high-value chemicals and fuels. In this work, we show the main advances of the last five years in the use of pincer transition metal complexes in key catalytic processes aiming for a more sustainable chemical and energy production.

Emergence and Applications of Base Metals (Fe, Co, and Ni) in Hydroboration and Hydrosilylation

Base metal catalysis offers an alternative to reactions, which were once dominated by precious metals in hydrofunctionalization reactions. This review article details the development of some base metals (Fe, Co, and Ni) in the hydroboration and hydrosilylation reactions concomitant with a brief overview of recent advances in the field. Applications of both commercially available metal salts and well-defined metal complexes in catalysis and opportunities to further advance the field is discussed as well.

Telluraporphyrinoids: an interesting class of core-modified porphyrinoids

Core-modified porphyrinoids or heteroporphyrinoids are a class of porphyrinoids in which one or more core pyrrole nitrogen atom(s) of the macrocycles are replaced predominantly by group-16 atoms such as O, S, Se, and Te. Telluraporphyrinoids are distinct and interesting from the rest of the chalcogenide atom(s) containing porphyrinoids owing to the larger size of Te and the consequent properties arising from it. The telluraporphyrinoid chemistry is only sporadically investigated and the developments are rather slow compared to the other lighter group-16 atom containing porphyrinoids. This perspective presents a concise overview of the developments that have taken place in the field of telluraporphyrinoid chemistry since its inception and includes various aspects such as the synthesis, structure, reactivity, and properties of tellurium-containing porphyrins and other related porphyrinoids such as vacataporphyrins, carbaporphyrins, calixphyrins, and expanded porphyrins.

Peripherally Metalated Porphyrins with Applications in Catalysis, Molecular Electronics and Biomedicine

Porphyrins are conjugated, stable chromophores with a central core that binds a variety of metal ions and an easily functionalized peripheral framework. By combining the catalytic, electronic or cytotoxic properties of selected transition metal complexes with the binding and electronic properties of porphyrins, enhanced characteristics of the ensemble are generated. This review article focuses on porphyrins bearing one or more peripheral transition metal complexes and discusses their potential applications in catalysis or biomedicine. Modulation of the electronic properties and intramolecular communication through coordination bond linkages in bis-porphyrin scaffolds is also presented.