Charles Hugo Devillers

s -Aryltetrazines are assembled into macrocyclic tri- and tetramers by direct C–C bond formation via Ullmann homocoupling of bromophenyltetrazines. Short aryltetrazine linkages afford compact redox-active macrocycles with small internal cavities.

Interface engineering in organic heterostructures is an important approach to tuning the characteristics of organic electronic devices and improving their performances in applications, such as gas sensing. Herein, organic heterostructures containing, a polyporphine (pZnP‐1), perfluorinated copper phthalocyanine (Cu(F₁₆Pc)), and lutetium bis‐phthalocyanine (LuPc₂) are synthesized by a combination of electrochemical and PVD methods for investigation of charge transport and ammonia (NH₃) sensing application. pZnP‐1 is synthesized by controlled oxidative electropolymerization and reveals a rough surface, which influences the electrical nature of its interface with the phthalocyanine. The electrical properties of the heterojunction devices reveal distinct interfacial and bulk charge transport properties, which are modulated by the thickness of pZnP‐1 and the external electric field. Indeed, the heterojunction device containing a thin film of pZnP‐1 displays n‐type behavior at low bias and p‐type nature at higher bias; i.e., an ambipolar behavior, in which ambipolarity is triggered by the external electric field. On the other hand, the heterojunction device having a thick film of pZnP‐1 exhibits p‐type behavior at all the studied biases. Investigation of NH₃ sensing properties of the heterojunction devices highlights the advantages of introducing pZnP‐1 in the heterostructures, which enhances the sensitivity, stability, repeatability, and humidity tolerance of the sensors.

Here we report the optimized synthesis of pentapyrroles. We succeeded in increasing the yield for pentapyrrole PPy 1a by heating at 100 [ ]C for 4.5 h. These conditions also allowed a greater increase in the yield for PPy 1c. In contrast, with PPy 1d and 1e possessing EDGs the formation of pentapyrroles was not observed. These pentapyrroles then allowed us to access sapphyrins (e.g. cyclic analogs of pentapyrroles) by electrosynthesis. The optimized conditions for obtaining the fluorinated sapphyrins 2a and 2b involve the addition of 10 mol% TBAI (tetra-n-butylammoniom iodide), 2 eq. of TFA in CHCl₃. In comparison with classical organic synthesis, the amount of TFA was considerably reduced from 100 to 2 eq. and the oxidizing agent, [ ].[ ]. iodine, was continuously electrogenerated from the catalytic amount of TBAI used as a redox mediator.

A new route for the synthesis of meso -(pyridin-2-ylmethyl)porphyrins was developed, based on the nucleophilic attack of (pyridin-2-ylmethyl)lithium reagent on a porphyrin bearing one free meso position. The latter is then metalated with Zn(II) and Ni(II). These products were characterized by NMR spectroscopy, UV–visible absorption spectroscopy, mass spectrometry and electrochemistry. Attempts to generate the C–N-fused compound by oxidation (new bond between the nitrogen of the pyridinyl substituent and the β-pyrrolic position of the porphyrin) are also described.

Electrochemical oxidation of Zn(II) 2,7,12,17‐tetra‐tert‐butylporphyrin in the presence of a series of azole derivatives (1‐methylimidazole, 1‐vinyl‐1H‐imidazole, 2‐(1H‐imidazol‐1‐yl)pyridine, 1‐methylbenzimidazole, 1‐methyl‐1H‐1,2,4‐triazole, and benzothiazole) affords the corresponding meso‐substituted azolium‐porphyrins in very mild conditions and good yields. It was found that these nucleophiles were strongly ligated to the zinc(II) azolium‐porphyrin complexes. Thus a demetalation/remetalation procedure was performed to recover the non‐azole‐coordinated zinc(II) complexes. X‐ray crystallographic structures of three azolium‐porphyrins were solved. Cyclic voltammetry analyses provided insight into the electron‐withdrawing effect of the azolium substituents.

5,15-Bis(pyrimidin-2-ylthio)porphyrins have been synthesized. Their electrochemical oxidation leads to the formation of mono- and bis-C-N-fused thiopyrimidinium intermediates depending on the applied charge and potential. These latter undergo nucleophilic attack with water during workup that drives the ring opening of the pyrimidinium moiety. When piperidine is added before or after workup, the neutral fused porphyrinthiazin-2-amines are generated, and they exhibit a significant bathochromic shift of their Soret and Q bands.

NHC-Rh(i) complexes with porphyrin wingtips are capable of cation-tunable reactivity suggesting the existence of a cooperative effect between Rh and M.