A Flexible Porphyrin–Annulene Hybrid: A Nonporphyrin Conformation formeso‐Tetraaryldivacataporphyrin

Abstract

An annulene-porphyrin hybrid, the diaaza-deficient porphyrin 5,10,15,20-tetraaryl-21,23-divacataporphyrin, has been synthesized by an extrusion of tellurium atom(s) from 5,10,15,20-tetraaryl-21,23-ditelluraporphyrin under treatment with HCl. In addition, a monoaza-deficient 5,10,15,20-tetraaryl-21-tellura-23-vacataporphyrin was formed in the same reaction. The two new members of the vacataporphyrin family were characterized by X-ray crystallography, as well as UV/Vis and NMR spectroscopy. These aromatic molecules preserve the fundamental structural and spectroscopic features of the parent tetraarylporphyrin. The X-ray crystal structures of 21,23-divacataporphyrin and 21-tellura-23-vacataporphyrin show typical porphyrin patterns. The molecules are not strictly planar and show distortion of the annulene moieties. The N22⋅⋅⋅N24 distances (5.23 and 5.09 Å) are considerably longer than in regular porphyrins. For 21,23-divacataporphyrin, variable-temperature (1)H NMR spectroscopy data allowed the identification of divacataporphyrin stereoisomers differentiated by the geometry of the butadiene bridges. The forms remain in thermodynamic equilibrium.

Incorporation of a Phenanthrene Subunit into a Sapphyrin Framework: Synthesis of Expanded Aceneporphyrinoids

“…2,5‐Bis(phenylhydroxymethyl)tellurophene ( 2 ‐Te) : Compound 2 ‐Te was synthesized according to a literature procedure …”

“…[6] 2,5-Bis(phenylhydroxymethyl)tellurophene (2-Te):C ompound 2-Te was synthesized according to aliterature procedure. [47] 11,26-Diphenyl-16,21-ditolyl-5,6-dimethoxy-32-thiaphenanthrisapphyrin (3-S):3 ,6-Bis(phenyl-(2-pyrolyl)hydroxymethyl)-9,10-dimethoxyphenanthrene (1)( 548 mg, 1.0 mmol) and 2,5-bis(tolylhydroxymethyl)thiophene (2-S) (324 mg, 1.0 mmol) were added to dry dichloromethane (900 mL) under argon. The solution was deoxygenated for 15 min by purging with argon.…”

Shaping a Porphyrinoid Frame by Heteroatoms Extrusion: Formation of an Expanded [22]Triphyrin(6.6.0)

“…Moreover, the crystal structure allowed for identification of the complex nature of the counter‐ions, that is, hexabromotellurate (TeBr 6 2− ; major form) and pentabromotellurate (TeBr 5 − ; minor form) anions disordered mixture (details in the Supporting Information). Thus, for the first time, the tellurium atom extruded from a tellura‐porphyrinoid has been captured in complex anions, which are routinely disintegrated and lost during any chromatographic workup that followed similar vacatization reactions …”

“…The employed tellurium‐extrusion method for introduction of a core‐modification in an aromatic porphyrinoid, previously applied in our laboratory for 21‐telluraporphyrin and 21,23‐ditelluraporphyrin to yield various vacataporphyrins, proved that the so called vacatization reaction is a versatile and efficient synthetic protocol for the construction of new porphyrinoid‐annulene crossbreeds …”

Vacata- and divacataporphyrin: New photosensitizers for application in photodynamic therapy-an in vitro study

“…The structural formula of VP (21‐vacata‐5,20‐diphenyl‐10,15‐bis(4‐methoxyphenylporphyrin) and 21,23‐divacata‐5,10,15,20‐tetra(4‐methoxyphenylporphyrin), DVP, are shown in Figure 1. These porphyrins were originally synthesized by extrusion of tellurium atom from 21‐telluraporphyrin under a treatment of HCl 16–18. The absorption spectra of VP and DVP are shown in Figure 2.…”