meso‐Dibenzoporphycene has a Large Bathochromic Shift and a Porphycene Framework with an UnusualcisTautomeric Form

Abstract

meso-Monobenzoporphycene (mMBPc) and meso-dibenzoporphycene (mDBPc), in which one or two benzene moieties are fused at ethylene-bridged positions (meso-positions) of porphycene, were prepared in an effort to further delocalize the π-electrons within the porphycene molecule. mMBPc and mDBPc were fully characterized by mass spectrometry, (1)H and (13)C NMR spectroscopy, and X-ray crystallography. The longest-wavelength Q-bands of mMBPc and mDBPc are red-shifted by 92 nm and 418 nm, respectively, compared to that of the unsubstituted porphycene (Pc). Electrochemical measurements indicate that the HOMO is destabilized and the LUMO is stabilized by the fused benzene moieties at the meso positions. Furthermore, both XPS and theoretical studies support the presence of a cis tautomeric form in the ground state of mDBPc, despite the fact that essentially all known porphycene derivatives adopt the trans tautomeric form.

An Expanded Porphycene with High NIR Absorptivity That Stabilizes Two Different Kinds of Metal Complexes

“…Both 2 and 3 display red‐shifted absorption features compared to 1 , reflecting an increase in the electronic pathway from 18 to 26 π‐electrons. The annulated meso ‐dibenzoporphycene derivative 4 also displays a red‐shifted infrared absorption maximum (in the NIR) . However, neither 2 nor 3 (nor 4 or any other porphycene derivatives that we are aware of) has been reported as being effective in stabilizing a bis(metal) complex.…”

An Expanded Porphycene with High NIR Absorptivity That Stabilizes Two Different Kinds of Metal Complexes

“…Thea nnulated meso-dibenzoporphycene derivative 4 also displays ar ed-shifted infrared absorption maximum (in the NIR). [17] However,n either 2 nor 3 (nor 4 or any other porphycene derivatives that we are aware of) has been reported as being effective in stabilizing abis(metal) complex. We thus sought to prepare an expanded porphycene derivative that would both display strong NIR absorption features and permit the coordination of more than one metal center.…”

Acid- and hydrogen-bonding-induced switching between 22-π and 18-π electron conjugations in 2-aminothiazolo[4,5-c]porphycenes

“…The expanded porphycenes result from the insertion of sp-or sp 2 -hybridized carbons or heterocyclic rings into the bridge connecting the pyrroles. 20,21 On the other side, fusedporphycenes result from the fusion of cycles containing sp-or sp 2 -carbons or heteroatoms in the b,b 022 or meso-positions 11,23,24 of the macrocycle. Both porphycene families have red-shifted absorption and fluorescence spectra with respect to their parent 18-p as a result of the larger aromatic system.…”

“…Both porphycene families have red-shifted absorption and fluorescence spectra with respect to their parent 18-p as a result of the larger aromatic system. 11,[23][24][25] Of specific interest are meso-fused porphycene derivatives since this position is highly sensitive to the substituent nature. 18 However, their study has been challenging owing to difficult synthetic preparation 26 and extremely low emission quantum yields.…”