Core modified oxybenziporphyrins: new aromatic ligands for metalcarbon bond activation

Successful syntheses of two new aromatic core modified oxybenziporphyrins by a simple 3 + 1 methodology and the first aromatic core modified oxybenziporphyrin palladium complex are reported

Figure-eight aromatic core-modified octaphyrins with six meso links: syntheses and structural characterization

The synthesis and structural characterization of the first examples of aromatic core-modified figure-eight octaphyrins with six meso links and their formation with and without acid catalysts are highlighted

Novel Azepino-perylenebisimides: Synthesis, Structure, and Properties

info:eu-repo/semantics/publishe

Bay- and <em>ortho</em>- ring annulated perylenediimides: Synthesis and their panchromatic absorption

308-313Herein, we report the synthesis of semi-coronenediimide (sCDI) and N-caprolactam pyrrolo-perylenediimide (pPDI) using 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU). The reaction involves in situ removal of trimethylsilyl (TMS) group followed by a ring formation at the ortho and bay positions of perylenediimide (PDI). Both the molecules exhibit diverse photophysical properties. pPDI demonstrates panchromatic absorption with quenched fluorescence while sCDI displays blue-shifted absorption with high fluorescence quantum yield. The obtained sCDI has been structurally characterized

Novel Azepino-perylenebisimides: Synthesis, Structure, and Properties

The first example of an azepine ring formation by counterintuitive nucleophilic participation of DBU was observed at the sterically crowded bay area of electron-deficient perylenebisimide (PBI). This is also a rare example of the formation of a seven-membered ring via two consecutive C–N bond formations in a single step. Azepino-PBIs reveal panchromatic absorption covering the whole visible region. Further novelty of these PBIs lies within the fact that their photophysical characteristics can easily be modulated by suitable substituents

Smaragdyrinazobenzene conjugates: syntheses, structure, and spectral and electrochemical properties

The syntheses, characterization, and spectral properties of smaragdyrinazobenzene conjugates are reported. Our synthetic strategy involves linking the azobenzene group in one of the precursors to a dipyrromethane subunit, which was achieved by reaction of azobenzenecarbaldehyde with pyrrole under TFA catalysis. A [3+2] acid-catalyzed oxidative coupling of this precursor with the tripyrrane moiety gave the expected smaragdyrinazobenzene conjugates. The azobenzene is in the (E) conformation both in the precursor and in the smaragdyrin conjugates, as revealed by its single-crystal X-ray structure. Electronic absorption and emission spectral studies reveal the presence of a moderate electronic interaction between the azobenzene and smaragdyrin &#960;-systems. Irradiation experiments at 360 nm reveal the presence of a reversible (E)/(Z) transformation of the azobenzene moiety in the precursors 3b and 4b. However, in the smaragdyrin conjugates the formation of the (Z) conformer leads to the decomposition of the macrocycle upon prolonged irradiation. Excitation at the azobenzene absorption results in the appearance of the emission band of smaragdyrin, thereby suggesting an energy transfer. The electrochemical data reveal that ring oxidations of the smaragdyrin macrocycle become harder upon azobenzene introduction, which suggests the electron-withdrawing nature of the azobenzene in these conjugates. A significant shortening of the NN bond (0.067 &#197;) and elongation of the CN bonds (0.055 and 0.069 &#197;) in 7a relative to the azobenzenedipyrromethane precursor 4a clearly reveal a rearrangement of the electronic &#960; -delocalization pathway in the smaragdyrinazobenzene conjugates. Rh<SUP>I</SUP> binds to one amino and one imino nitrogen atom in the smaragdyrin cavity to form a 1:1 complex

Modified corroles with one meso-free carbon: synthesis and characterization

Synthesis of mono meso-free modified corroles by a [3+1] methodology is reported

Metal-free Annulation at the <i>Ortho</i>- and <i>Bay</i>-Positions of Perylene Bisimide Leading to Lateral π‑Extension with Strong NIR Absorption

A novel <i>ortho</i>/<i>bay</i> annulation reaction of perylene bisimide (PBI) has been explored in a single step synthetic procedure using perylene bisimide <b>1</b> and 1,8-Diazabicyclo[5.4.0]­undec-7-ene (DBU) in the absence of any metal catalyst. The single crystal solid-state X-ray diffraction structure showed a distorted framework of DBU-fused PBI <b>2</b>. Compound <b>2</b> exhibited intense near-infrared absorption up to 950 nm. Reversible protonation and deprotonation accompany drastic changes in the photophysical characteristics. Further, the reaction of perylene biscarboxyanhydride with DBU offered a caprolactam ring-substituted perylene bisimide <b>3</b>

Metal-free Annulation at the <i>Ortho</i>- and <i>Bay</i>-Positions of Perylene Bisimide Leading to Lateral π‑Extension with Strong NIR Absorption

A novel <i>ortho</i>/<i>bay</i> annulation reaction of perylene bisimide (PBI) has been explored in a single step synthetic procedure using perylene bisimide <b>1</b> and 1,8-Diazabicyclo[5.4.0]­undec-7-ene (DBU) in the absence of any metal catalyst. The single crystal solid-state X-ray diffraction structure showed a distorted framework of DBU-fused PBI <b>2</b>. Compound <b>2</b> exhibited intense near-infrared absorption up to 950 nm. Reversible protonation and deprotonation accompany drastic changes in the photophysical characteristics. Further, the reaction of perylene biscarboxyanhydride with DBU offered a caprolactam ring-substituted perylene bisimide <b>3</b>

Core-modified expanded porphyrins with large third-order nonlinear optical response

The third-order nonlinear optical response through measurement of two-photon absorption cross-sections (TPACS) for aromatic core-modified expanded porphyrin analogues by a femtosecond open aperture Z-scan method is reported. The values reported here are among the largest known so far in the literature for any organic molecules