meso‐Cumulenic 2H‐Corroles from meso‐Ethynyl‐3H‐corroles

Abstract

Alkynyl-substituted 3H-corrole 9 a was converted to [3]cumulenic 2H-corrole 10 a by treatment with trimethylsilyl chloride (TMSCl), and 1,3-butadiyne-bridged 3H-corrole dimer 11 b was transformed into [5]cumulene-bridged 2H-corrole dimer 12 b by oxidation with PbO . Both 10 a and 12 b were metalated to form Zn complexes 10 a-Zn and 12 b-Zn. The structures of 10 a-Zn and 12 b-Zn show planar conformations with bond-length alternations that are analogous to those of tetraaryl [n]cumulenes. The cumulenic corrole dimers 12 b and 12 b-Zn display large NIR absorption bands in the range of 700-1400 nm (maximum ϵ≈1.0×10 m cm ) owing to the effective π-conjugation between the two corrole units through the [5]cumulene bridge.

Synthesis and characterization of meso-substituted A2B corroles with extended π-electronic structure

“…In contrast to the results of Gryko et al [ 19 ] and Osuka et al [ 20 ] the deprotection of 2 occurred within few minutes with 1.5 eq. of TBAF (Scheme 4 ) and was determined via mass spectroscopy and UV–Vis measurements (see electronic supporting information).…”

“…Alkynyl groups as linker between the corrole core and the aromatic systems could prevent this behavior and would enlarge the π-electron conjugation. Recently, Osuka et al presented a new methodology to synthesize meso -cumulenic 2 H -corroles from a meso -ethynyl-3 H -corrole as precursor [ 20 ].…”

Singly, Doubly, and Triply Linked Corrole Oligomers: Synthesis, Structures, and Linking Position Dependent Properties

“…UV‐Vis absorption spectra of 20 showed a deep absorption bands in NIR region, indicating effective conjugation between the corrole segments via [5]cumulene bridge. Reduction of 20 to 19 was performed by the treatment of hydrazine in 67 % yield, thus representing the first example of reversible interconversion between 1,3‐butadiyne and [5]cumulene . The 2NH ‐cavity of cumulenic corrole 20 can accommodate zinc(II) ions to give zinc(II) complex 20Zn in moderate yields.…”

“…Reduction of 20 to 19 was performed by the treatment of hydrazine in 67 % yield, thus representing the first example of reversible interconversion between 1,3-butadiyne and [5]cumulene. [29] The 2NH-cavity of cumulenic corrole 20 can accommodate zinc(II) ions to give zinc (II) complex 20Zn in moderate yields. The precise bond lengths were analyzed by the X-ray diffraction analysis of the metal complexes 19 Ag and 20Zn ( Figure 5).…”

meso‐Cumulenic 2H‐Corroles from meso‐Ethynyl‐3H‐corroles

“…Further exploration of novel corrole-based functional molecules are ongoing in our laboratory. [19] Bond lengths are displayed in .Thermal ellipsoidsw ere scaled to 50 %probability level. meso-Aryl substituents, solvent molecules, and hydrogen atoms were omitted for clarity.One of two independent molecules in the asymmetric unit of 10 a-Zn is shown, and the bond lengths are averaged.…”