β-Tetrakis(2-thienyl)-meso-tetraphenylporphyrins: Synthesis, structural and electrochemical redox properties

Switching the Macrocycle Conformation from Nonplanar to Planar in Cobalt(II) and Copper(II) β‐Tetra‐2′‐thienyl‐meso‐tetraphenylporphyrin Cocrystallates with C60

“…It is worth mentioning that the porphyrin rings in the solvated MTPP(2Ј-thienyl) 4 ·C 60 cocrystallates (Table 1) are nearly planar, while the ring is nonplanar in the reported MTPP(2Ј-thienyl) 4 structures. [24] This is also reflected by the side-view and mean plane displacement of the core atoms of the macrocyclic ring (Supporting Information). The flattening of the MN 4 core in both of the cocrystallates is reflected by the value of the (N-M-N) opp angle [179.9(1)°]; these angles are 173.0(1)°and 174.9(1)°in the nonplanar CoTPP(2Ј-thienyl) 4 and CuTPP(2Ј-thienyl) 4 , respectively.…”

“…This is also reflected in the N···N and NЈ···NЈ distances, which are longer along the pyrroles bearing thienyl groups in both cocrystallates relative to those in their parent solvated MTPP(2Ј-thienyl) 4 structures. [24] Such longer M-N distances arise from the electron-withdrawing effect of the thienyl groups at the β-pyrrole carbon atoms. The elongation of M-N and M-NЈ bonds in the cocrystallates contradicts the trend reported for MTPP(Ph) 4 ·C 60 (M = Co II and Cu II ); [21] however, the (Co-N) av bond length is expected to be shorter than (Cu-N) av .…”

“…The observed close contact distances indicate the existence of weak intermolecular interactions. [29] Further, the redox potentials of the host and the ease of first-ring oxidation and reduction of MTPP(2Ј-thienyl) 4 compounds [24] (relative to MTPPs) perhaps induce greater attractive interaction between the porphyrin and C 60 .…”

“…Fullerene, C 60 , was purchased from Sigma-Aldrich (India) and used without further purification. The MTPP(2Ј-thienyl) 4 (M = Co II and Cu II ) complexes were prepared by a reported procedure, [24] and they were characterized by electronic absorption, 1 H NMR spectroscopy, and mass spectrometry.…”

Planar and Nonplanar Free‐Base Tetraarylporphyrins: β‐Pyrrole Substituents and Geometric Effects on Electrochemistry, Spectroelectrochemistry, and Protonation/Deprotonation Reactions in Nonaqueous Media

“…TFA and 5,10,15,20-tetraphenylporphyrin, H 2 TPP (1) purchased from Aldrich was used without further purification. The other free-base porphyrins, 2-10, were synthesized according to literature procedures [44,[59][60][61][62][63][64] and characterized by UV/Vis, 1 H NMR spectroscopy, and mass spectroscopic methods. Calculation of protonation constants: Changes in the UV/Vis spectra of 1-10 in CH 2 Cl 2 were monitored during a titration with TFA and the resulting spectral data then used to calculate formation constants for proton addition by using the Hill equation [65] (Equation 4) in which A i is the absorbance in solutions with a specific concentration of added protons [H + ], A 0 is the initial absorbance in which [H + ] = 0.0 and A f is the final absorbance of the fully protonated porphyrin.…”