Michal Kryjewski

Ruthenium-Catalyzed C-H Arylation of Benzoic Acids and Indole Carboxylic Acids with Aryl Halides

Abstract Herein we report the first Ru‐catalyzed C−H arylation of benzoic acids with readily available aryl (pseudo)halides. The reaction, which does not require the use of silver salt additives, allows the arylation of previously challenging hindered benzoic acids and the use of generally unreactive ortho‐substituted halorarenes. Furthermore, our new protocol can efficiently be applied to indole carboxylic acids, thus allowing access to C7‐, C6‐, C5‐ and C4‐arylated indole compounds, a departure from the classical enhanced reactivity of the C2 and C3 positions of indole.

Synthesis and singlet oxygen generation of pyrazinoporphyrazines containing dendrimeric aryl substituents

Pyrazinoporphyrazines and tribenzopyrazinoporphyrazines were synthesized and studied towards their potential applications in photodynamic therapy. The macrocycles were obtained via Linstead macrocyclization with good yields. The expansion of the porphyrazine periphery with hyperbranched aryl substituents was beneficial in terms of purification and isolation of compounds, effectively hampering their aggregation tendency in different concentrations. The obtained macrocycles were assessed for their singlet oxygen generation quantum yields and revealed far better efficacies for tribenzopyrazinoporphyrazines than pyrazinoporphyrazines. A comparison of the crystal packing of two 2,3-dicyanopyrazine derivatives revealed that the recurring motif of the supramolecular architecture is a dimer formed by π–π stacking interactions between aromatic pyrazine and phenyl rings of the inversion center related molecules.

Experimental and computational study on the reactivity of 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile, a key intermediate for the synthesis of tribenzoporphyrazine bearing peripheral methyl(3-pyridylmethyl)amino substituents.

An earlier developed alkylating path leading to tetraalkylated diaminomaleonitrile derivatives was explored. Attempts to explain the reactivity of the representative dialkylated diaminomaleonitrile 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile during the alkylation reaction were performed using X-ray and density functional theory (DFT) studies. The condensed Fukui functions accompanied by softness indices were found to be useful in explaining its reactivity observed during the reaction. The values of the Fukui functions and condensed softness for electrophilic attack calculated from Mulliken, Löwdin, and natural population analyses closely corresponded to the experimental observations. When 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile disodium salt was treated with dimethyl sulfate at lower temperatures the alkylation reaction prevailed, whereas at higher temperatures the alkylating agent acted as a hydride anion acceptor, which favored the elimination reaction. The tetraalkylated dinitrile 2,3-bis[methyl(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile was used in the synthesis of tribenzoporphyrazine bearing methyl(3-pyridylmethyl)amino groups, which was subsequently subjected to solvatochromic and metallation studies. The changes observed during metallation seem to result from the coordination of the 3-pyridyl group by a palladium ion. This could influence the configuration of the methyl(3-pyridylmethyl)amino moiety, causing more effective donation of a lone pair of electrons from peripheral nitrogen to the macrocyclic ring.Graphical abstract.

Magnesium(II) 1-(1-adamantylsulfanyl)phthalocyanine – synthesis, photochemical and electrochemical properties

A mixed macrocyclization reaction of 3-(1-adamantylsulfanyl)-1,2-dicyanobenzene and 1,2-dicyanobenzene led to unsymmetrical magnesium(II) 1-(1-adamantylsulfanyl)phthalocyanine. The novel macrocycle was characterized using UV-Vis, MS MALDI and NMR spectroscopy. The spectroscopic study of solvatochromic effects indicated that the changes observed in the electronic absorption spectra are mainly a result of solvation, and that the coordinating strength of the solvent had little influence on the red shift. The novel magnesium(II) phthalocyanine derivative revealed in DMF and DMSO the fluorescence quantum yield (Φf) values of 0.30 and 0.35, and singlet oxygen quantum yield (ΦΔ) values of 0.32 and 0.25, respectively. The magnesium(II) phthalocyanine derivative displayed in the voltammetric study four sets of redox peaks, two one-electron oxidations, and two one-electron reductions, which were assigned to ring based one electron processes.