N-porphyrinylamino and -amido compounds by addition of an amino or amido nitrogen to a porphyrin meso position

BODIPY-amino acid conjugates – tuning the optical response with a meso-heteroatom

The presence of a heteroatom at the meso-position of BODIPY significantly influences the π-cloud of the main chromophore, modifying the final optical properties.

A controlled blue-shift in meso-nitrogen aryl fused DIPY and BODIPY skeletons

An aryl-amine attached to the meso-position of the BODIPY skeleton quenches the fluorescence. The observed edge fusion creates a new heterocyclic subunit simultaneously increasing the efficiency of emission. The quantitative deprotonation of meso NH functionality leads to absorbance blue shift and increased emission quantum yield showing potential for formation of BODIPY based changeable chromophores.

Diarylamine-Fused Subporphyrins: Proof of Twisted Intramolecular Charge Transfer (TICT) Mechanism

Diarylamine-fused subporphyrins 1 a and 1 b were synthesized from β,β-diiodo-meso-chloro subporphyrin 2 through a one-pot procedure involving nucleophilic aromatic substitution and S_RN 1-type intramolecular fusion reaction as the first example of meso-nitrogen-embedded subporphyrin. While non-fused counterparts 3 b and 4 b display effective fluorescence quenching due to twisted intramolecular charge transfer (TICT) in CH₂ Cl₂ at room temperature, 1 b emits fluorescence with Φ_F =0.18 under the same conditions, because conformational twisting is not allowed due to the fused structure. In addition, the oxidative titration with tris(4-bromophenyl)ammoniumyl hexachloroantimonate gave cation radical 7 for 1 a and cation radical and dication for 1 b. Actually, cation radical 7 was isolated through separation over silica gel column but was found to slowly decompose in concentrated solutions.

Direct and Regioselective Amination of β-Unsubstituted 5,15-Diazaporphyrins with Amines: A Convenient Route to Near-Infrared-Responsive Diazaporphyrin Sensitizers

We have established a convenient method for the base-promoted direct amination of β-unsubstituted 5,15-diazaporphyrins (DAPs) with secondary and primary amines to produce 3,7,13,17-tetraamino- and 3-amino-DAPs, respectively, regioselectively. The amino groups attached at the periphery cause significant red shifts of the absorption bands as a result of their perturbation of the HOMO and/or LUMO in the DAP π-system. The palladium complex of a 3,7,13,17-tetrakis(diphenylamino)-DAP generated singlet oxygen in high yield under irradiation with near-infrared light.

Embedding heteroatoms: an effective approach to create porphyrin-based functional materials

Incorporation of planarized heteroatom(s) onto the porphyrin periphery is an effective approach to create porphyrin-based functional materials. In the last three decades, such an "embedding heteroatom" strategy has been actively explored in order to realize attractive electronic, optical, and electrochemical properties. This review aims to cover a variety of synthetic methodologies that have been developed for the construction of heteroatom-embedded porphyrins. Moreover, we also summarize their structure-property relationships as well as possible applications in various research fields including artificial photosynthesis, molecular engineering, organic electronics, and bioimaging.

meso-N-Pyrrole as a Versatile Substituent Influencing the Optical Properties of Porphyrin

A meso-N-pyrrole porphyrin converts into a π-extended porphyrin forming an indolizine-3-one motif. The indolizine-3-one frame opens a lactam subunit preserving a six-membered, heterocyclic structure fused with the main macrocycle. The optical properties of formed derivatives follow the structural modifications giving the absorbance and emission eventually modulated by the NH-centered modifications of the fused unit.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

Meso-N-arylamino- and N, N-diarylaminoporphyrinoids: Syntheses, properties and applications

This review is devoted to porphyrinoids with N-arylamino groups tethered directly to their meso positions, the study of which has significantly progressed in the past two decades. After a brief introductory description, various synthetic procedures for these compounds are described. The third section focuses on their photochemical and electrochemical properties, and reviews the synergetic effects that arise between the porphyrinoids and the N-arylamino groups. Potential applications are then discussed, focusing on dye-sensitized solar cells (DSSCs).

A fused meso-aminoporphyrin: a switchable near-IR chromophore

meso-Nitrogen acts as a switch controlling the absorption and emission properties of the fused meso-aminoporphyrin.

Synthesis of extended porphyrins by connection of meso-aryl groups with β-pyrrolic positions

This review focuses on synthetic strategies leading to extended porphyrins, but is limited to examples in which at least one β-pyrrolic carbon is linked to a meso-aryl substituent. Friedel–Crafts reactions are covered first because historically they were the first reactions employed to link β-pyrrolic carbons with meso-aryl groups, thus creating new six-membered fused rings. Other reactions inserting heteroatoms follow. Direct cyclizations between an ortho-carbon and a β-pyrrolic position are presented next. Finally, new highly extended chromophores are described. These compounds are generally obtained in two consecutive reactions. First a Suzuki coupling is used to introduce an aryl group in one or two meso positions. Then the new fused rings are generated by oxidative cyclizations.

General Synthesis of meso-Amidoporphyrins via Palladium-Catalyzed Amidation

A series of meso-amidoporphyrins were facilely synthesized by direct reactions of meso-brominated porphyrins with amides via palladium-catalyzed amidation reaction. Using a combination of palladium precursor Pd(OAc)(2) or Pd(2)(dba)(3) and phosphine ligand Xantphos, both 5-bromo-10,20-diphenylporphyrin and 5,15-dibromo-10,20-diphenylporphyrin, as well as their zinc complexes, can be effectively coupled with a wide variety of amides to give the corresponding mono- and bis-substituted meso-amidoporphyrins in high yields under mild conditions. [reaction: see text]