Preparation and Characterization of Nonclassical Tetraazaporphyrin, Bis(4‐methylpyridine)[1,3,5,7,9,11,13,15‐octaphenyltetra(3,4‐thieno)tetraazaporphyrinato]ruthenium(II)

Abstract

The tetramerization reaction of 2,5‐diphenyl‐3,4‐dicyanothiophene (2) proceeded on treatment with ruthenium(III) trichloride, DBU, and 4‐methylpyridine in 2‐ethoxyethanol at 135 °C to give bis(4‐methylpyridine)[1,3,5,7,9,11,13,15‐octaphenyltetra(3,4‐thieno)tetraazaporphyrinato]ruthenium(II)(3). Because the structure of this product cannot be represented by a usual bonding system, this molecule has to contain an unusual tetravalent sulfur atom in one of the four thiophene rings. In the 1H NMR spectrum of the product, signals from 4‐methylpyridine coordinated to the central ruthenium atom showed an upfield shift. The structure of 3 was determined by X‐ray crystallography, which revealed that 3 has four thiophene units linked at their 3,4‐positions to the tetraazaporphyrin scaffold. Four pairs of phenyl groups are in close proximity and are sterically congested, which causes the four thiophene rings to deviate from the mean plane of the central four pyrrole nitrogen atoms. The UV/Vis spectrum of 3 shows a Q‐band absorption at λmax = 758 nm. In the MCD spectrum of 3, dispersion‐type absorptions (Faraday A term) are observed at 746 and 776 nm. The MCD spectra suggest that the two LUMOs of 3 could be degenerate even though its structure deviates from D4h symmetry. The electrochemical properties of 3 were examined by cyclic voltammetry with Ag/AgNO3 as the reference electrode. The optimized structure and the NMR shielding constants of a simplified model molecule were calculated by using density functional theory.

Core‐Modified Rubyrins Containing Dithienylethene Moieties

“…Although alternating single and double bonds cannot be drawn for the "open-form" structure of 2 (Scheme 1), when viewed in the context of molecular orbital theory, the spectroscopic properties can still be analyzed using theoretical frameworks that have been derived for conjugated macrocycles. [20] First, it is noteworthy that the nodal patterns of the HOMO and HOMOÀ1 and also the LUMO and LUMO + 1 of 1 are consistent with what would be anticipated for a heteroaromatic 26 pelectron porphyrinoid (Support-Scheme 3. Synthesis of core-modified rubyrin 2.…”

Preparation and optical properties of polyimide films linked with porphyrinato Pd (II) and Pt (II) complexes through a triazine ring and application toward oxygen sensors

“…In the course of our study of phthalocyanine and tetraazaporphyrin derivatives, we have thought that PI films have potential applications in sensors, optoelectronic devices, and photovoltaic cells if porphyrin derivatives could be conjugated to the PI backbone. Therefore, we designed PI directly bonded to metalloporphyrin derivatives as functional groups and, in this case, the triazine ring served as a linker between the polymer main‐chains and porphyrin moieties.…”

Preparation of 1,3‐Diphenylselenophenotetraazaporphyrinato Ruthenium(II) Bis(4‐methylpyridine) by the Reaction of 3,4‐Dicyano‐2,5‐diphenylselenophene and Phthalonitrile: Its Optical and Electrochemical Properties

“…In this compound, four thiophene units are linked at the 3,4‐positions [3,4‐TTTAP]; therefore, it is required that one of the thiophene rings contains an unusual tetravalent sulfur atom (Fig. ) . We recently reported the first structure determination of a ruthenium(II) complex of 3,4‐TTTAP having eight phenyl groups on the thiophene rings and two 4‐methylpyridines as axial ligands [3,4‐TTTAP‐Ph8] .…”

“…) . We recently reported the first structure determination of a ruthenium(II) complex of 3,4‐TTTAP having eight phenyl groups on the thiophene rings and two 4‐methylpyridines as axial ligands [3,4‐TTTAP‐Ph8] . Phthalocyaninato ruthenium(II) complexes can link two axial coordinating groups and are stable.…”

“…In contrast, to our knowledge, tetra(3,4‐selenopheno)tetraazaporphyrin [3,4‐TSTAP] has never been reported yet. To prepare 3,4‐TSTAP, 3,4‐dicyano‐2,5‐diphenylselenophene ( 4 ) was prepared from selenophene via four step reactions and tetramerization of 4 was attempted by a method reported previously . On the other hand, if 4 and phthalonitrile are combined and cyclized, unsymmetrically substituted TAPs can be obtained in a statistical manner.…”