Design and Synthesis of Perpendicularly Connected Metal Porphyrin–Imide Dyads for Two‐Terminal Wired Single Molecular Diodes

Meso bromination and derivatization of synthetic bacteriochlorins

Twelve bacteriochlorin building blocks featuring meso-substitution have been prepared including a set with finely tuned long-wavelength absorption (725–757 nm) for studies in photonics.

Regioselective C-H amination of free base porphyrins via electrogenerated pyridinium-porphyrins and stabilization of easily oxidized amino-porphyrins by protonation

Four free base aminoporphyrins were synthesized in two steps via regioselective anodic nucleophilic substitution with pyridine followed by ring opening of the electrogenerated pyridinium with piperidine. The X-ray crystallographic structure of the unstable 2-aminotetraphenylporphyrin was solved. Protonation of this latter compound leads to the stable diiminium porphyrin salt.

Three site molecular orbital controlled single-molecule rectifiers based on perpendicularly linked porphyrin-imide dyads

The original single-molecule rectifier proposed by Aviram and Ratner is based on a donor-σ-acceptor structure, in which σ functions as the insulator to disconnect the π electronic systems of the two parts. However, there have been no reports on experimentally demonstrated highly efficient single-molecule rectifiers based on this mechanism. In this paper, we demonstrate single-molecule rectifiers with perpendicularly connected metal porphyrin-imide dyads. Our proposed molecule rectifiers use hydroxyl groups at both ends as weak anchoring groups. Measurements of the single-molecule current-voltage characteristics of these molecules clearly show that the rectification ratio reached a high value of 14 on average. Moreover, the ratio could be tuned by changing the central metal in the porphyrin core. All of these features can be explained by the energy-level shift of the molecular orbital using a model with three electronic parts.

Observation of current rectification by the new bimetallic iron(iii) hydrophobe [Fe(LN4O6)] on Au|LB-molecule|Au devices

Targeting the development of stimulus-responsive molecular materials with electronic functionality, we have synthesized and studied the redox and electronic properties of a new bimetallic iron hydrophobe [FeIII2(LN4O6)] (1). The new H6LN4O6 ligand displays bicompartmental topology capable of accomodating two five-coordinate HSFeIII ions bridged by tetraaminobenzene at a close distance of ca. 8 Å. We show that the metal-based reduction processes in (1) proceed sequentially, as observed for electronically coupled metal centers. This species forms a well-defined Pockels-Langmuir film at the air-water interface, with collapse pressure of 32 mN m-1. Langmuir-Blodgett monolayers were deposited on gold substrates and used to investigate current-voltage (I-V) measurements. This unprecedented bimetallic hydrophobe [FeIII2(LN4O6)] (1) shows unquestionable molecular rectification and displays a rectification ratio RR between 2 and 15.

Synthesis and applications of rhodium porphyrin complexes

A review on rhodium porphyrin chemistry, ranging from synthesis and properties to reactivity and application.

Molecular rectifiers based on five-coordinate iron(iii)-containing surfactants

The state-of-the-art of metallorganic-based molecular rectification is reviewed with an emphasis on asymmetric five-coordinate Fe^III-containing surfactants in electrode|LB film|electrode assemblies.

A naphthalene benzimidazole-based chemosensor for the colorimetric and on-off fluorescent detection of fluoride ion

A novel naphthalene benzimidazole (NBI)-based chemosensor (D2) was developed for fluoride ion (F^-) detection. The absorption spectrum of D2 changed dramatically from yellow to blue in the visible region accompanied with a 225nm red shift of its absorption maximum upon the addition of F^- in DMSO. D2 also exhibited a fluorescence turn-off response towards the fluoride ion. The emission intensity of D2 decreased drastically along the increasing F^- concentration and the detection limit for F^- was as low as 3.2×10^-9mol/L. ¹H NMR and HRMS-ESI results indicated that the formation of NBI-O^- through the desilylation reaction of F^- with NBI-OSi was responsible for the spectral changes. Overall, this kind of NBI-type molecules represent a new type chemosensor for the spectral detection of fluoride ion in solution.

Synthesis of a series of Zinc(II)/freebase porphyrin dimers and trimers with programmable sequences from a common key molecule

We have developed a new methodology that enables the synthesis of any sequence of metal porphyrin arrays starting from a common key molecule. Using this method, we prepared porphyrin dimers and trimers with varying component unit sequences via consecutive Suzuki coupling reactions using the same key porphyrin compound under the same reaction conditions. The key porphyrin compound was synthesized on a gram scale in one batch, and the coupling reactions afforded the desired oligomers in good yields. Thus, the prepared porphyrin arrays showed unique physical properties depending on the sequence of the central metals. The reaction is potentially applicable for the automated synthesis of porphyrin arrays.