24389-79-5

Upstream product

• 110-86-1 pyridine 
• 14074-80-7 zinc tetraphenylporphyrin 
• 14074-80-7 (5,10,15,20-tetraphenylporphyrinato)zinc(II) 

Downstream Products

• 119391-04-7 pyridine zinc tetraphenylporphyrin cation radical 
• 3225-29-4 p-benzosemiquinone radical anion 

Relevant academic research and scientific papers

Versatile chiroptics of peptide-induced assemblies of metalloporphyrins

Zinc porphyrin functionalized with double long-chain alkylated l-glutamide (GTPP-Zn) was synthesized for the first time, and its self-assembling behaviour was investigated in nonpolar organic solvents. The uniqueness of this functionalized porphyrin is characterized by its drastic colour change from dark green to purple via the formation of chirally stacked structures through selective axial coordination on zinc with pyridine derivatives. In this paper, we report the versatility of the GTPP-Zn assembly process as a stimuli-responsive chiroptical switching system and describe the remarkable ligand-specific induction of secondary chirality accompanied by aggregation morphological change.

Exploring the self-assembly and energy transfer of dynamic supramolecular iridium-porphyrin systems

We present the first examples of dynamic supramolecular systems composed of cyclometalated Ir(iii) complexes of the form of [Ir(C^N)2(N^N)]PF6 (where C^N is mesppy = 2-phenyl-4-mesitylpyridinato and dFmesppy = 2-(4,6-difluorophenyl)-

Synthesis of new porphyrin/fullerene supramolecular assemblies: A spectroscopic and electrochemical investigation of their coordination equilibrium in solution

Two new fullerene ligands have been designed to provide relatively simple frameworks to build supramolecular systems containing both fullerene and Zn-porphyrin moieties. The coordination of the fullerene ligands to the Zn-porphyrin was supported by UV-vis

Study of extra coordination of bromo-substituted porphyrins to organic bases

Extra coordination of zinc complexes of bromo-substituted tetraphenylporphyrins was studied by spectrophotometry. It was found that the stability of complexes thus formed markedly increases upon β- bromosubstitution in tetraphenylporphine. The effects of

Meso-tetrathienylporphyrins: Electrochemical and axial ligation properties

5,10,15,20-Tetrakis(2′- and 3′-thienyl)porphyrins [H2T(2′-Thio)P and H2T(3′-Thio)P] and their metal [Zn(II) and Cu(II)] complexes were examined by electrochemical redox and axial ligation properties. A large anodic shift (100-150 mV) in reduction potentials was observed for MT(2′-Thio)Ps relative to MTPPs or MT(3′-Thio)Ps. MT(2′-Thio)Ps exhibited unusual redox behaviour and follows the trend in oxidation; CuT(2′-Thio)P>H2T(2 ′-Thio)P≥ZnT(2′-Thio)P in contrast to their corresponding MTPPs, H2TPP>CuTPP>ZnTPP. It is reflected in the enhanced equilibrium constants (60%) for the ligation of nitrogenous bases with ZnT(2′-Thio)P when compared to ZnTPP. This is interpreted in terms of increased electron deficient nature of the ZnT(2′-Thio)P in contrast to Zn(3′-Thio)P or ZnTPP.

Ligand-Assisted Electron Transfer from the Triplet State of Zinc Tetraphenylporphyrin to 1,4-Benzoquinone

Effects of axial ligands on the electron transfer from excited triplet state of zinc tetraphenylporphyrin (ZnTPP) to benzoquinone (BQ) have been studied by usung a laser flash technique.For the reaction of pyridinate complex of ZnTPP (Py-ZnTPP) as well as ZnTPP, quantum yield of the porphyrrin cation radicals resulting from the electron transfer, Φion, were determined in various solvents of different dielectric constant (ε).Remarkable enhancement in Φion due to axial ligation of pyridine has been found in the solvents having relatively moderate dielectric constant (9A comparison of the ε dependence of Φion for the reaction of the triplet ZnTPP to that for the triplet Py-ZnTPP has demonstrated that the axial pyridine causes partial neutralization of the effective charge of Py-ZnTPP cation radical.When the axial pyridine is replaced by several kinds of the substituted pyridines having different pKa, chloride ion, or ethanol, a significant change in Φion is revealed in dichloroethane.The change in Φion was found to depend on the ability of the ligand to transfer negative charge toward the porphyrin ring via the zinc ion.The ligand ability should cause reduction of effective charge on the porphyrin ring moiety of the ligand-bound ZnTPP cation radical which interacts with the BQ anion radical.Cosequently it has been concluded that the enhancement in Φion due to axial ligation is ascribed to the reduction of the effective charge of the cation radical which results in easier separation of the cation radical from its complex paired with BQ anion radical.

GOUTERMAN'S FOUR-ORBITAL MODEL AND THE MCD SPECTRA OF HIGH-SYMMETRY METALLOPORPHYRINS

This paper offers a description of the magnetooptical properties of highly symmetric metalloporphyrins within the framework of the Gouterman four-orbital model.Expressions are derived for the Faraday parameters of the Q and B (Soret) transitions of the porphyrin system as a function of the energy and intensity parameters and of the angular momenta of the relevant excited states.A discussion of these results highlights the distinct roles of two competing mechanism, which procure the Q band intensity.On the one hand this transition may steal intensity from the Soret band as a result of interstate interactions.On the other hand the zeroth order Q0 state may also carry a non-zero transition dipole moment as a consequence of the tetragonal symmetry of the porphyrin skeleton.The latter feature is a typical characteristic of the Gouterman model and does not occur in the algebraic solution of the perimeter model for cyclic ?-electron systems.In a final section MCD spectra are reported for meso- and exo-substituted zinc porphyrins and the corresponding cyanide and pyridine complexes.From these data Faraday parameters were extracted by using a Gausian fitting procedure.Parameter shifts caused by a change of the axial ligand are shown to follow the theoretical prediction.

Extraplanar ligand-exchange dynamics in (tetraphenylporphinato)zinc(II) and the conformation of zinc(II) porphyrins in solution

The extraplanar ligand-exchange dynamics of (tetraphenylporphinato)zinc(II) with pyridine and N-methylimidazole have been studied at 21°C in CDCl3. For the ZnTPP-py system we find kon = 4.90 × 108 M-1 s-1, koff = 1.98 × 105 s-1, and K = 2300 ± 400 M-1. For the ZnTPP-N-MeIm system we find kon = 1.67 × 108 M-1 s-1, koff = 4.78 × 104 s-1, and K = 10 200 ± 600 M-1. An analysis of the steric limitations of ZnTPP and the ligands (pyridine and N-methylimidazole) suggests that kon is close to, if not at, the diffusion-controlled rate limit. Since the ZnTPP-L complexes are known to have the Zn(II) displaced some 0.3 A? out of the mean plane of the porphyrin ring, a diffusion-controlled kon requires that the unligated ZnTPP also be nonplanar.

KINETICS OF COMPLEX FORMATION BETWEEN ZINC MESO-TETRAPHENYLPORPHYRIN AND SOME NITROGEN BASES IN APROTIC SOLVENTS, STUDIED BY AN IMPROVED MICROWAVE TEMPERATURE-JUMP METHOD

Rate and equilibrium constants have been determined over a range temperature for the reactions of zinc meso-tetraphenylporphyrin with pyridine (in chlorobenzene, 1-chlorobutane and toluene), with 2-methylpyridine (in 1-chlorobutane), and with imidazole (in 1-chlorobutane).Rates were measured by means of an improved microwave temperature-jump apparatus incorporating signal-averaging, and at low temperatures by the stopped-flow method, with spectrophotometric detection.The forward rate constants are lower by about an order of magnitude than the values calculated for diffusion control from the simple Smoluchowsky model.A two-step mechanis appears likely.Solvent and steric effects on the rate are discussed.

Reactions of metalloporphyrin π radicals. 1. Complexation of zinc tetraphenylporphyrin cation and anion radicals with nitrogenous bases

Stability constants for TPPZn with 20 nitrogenous bases were obtained by the method of proportional absorbances. These results were combined with electrochemical data to obtain stability constants for the reaction of TPPZn radical cations and radical anions with ligands. Values of log β1 ranged from 1.64 to 4.59 for ligand addition to [TPPZn]+ and from 1.47 to 3.50 for addition to [TPPZn]-. Only five-coordinate complexes were observed. These measurements represented the first values of stability constants obtained for nitrogeneous base addition to porphyrin π radicals. The changes in stability constants observed as a function of ligand pKa allowed the tuning of the zinc radical cation half-wave potential between 0.83 and 0.74 (vs. SCE) and the radical anion potential between -1.38 and -1.49 V. The ligand additions proceeded in a chemically reversible fashion over the experimental time frame. Thin-layer spectra for oxidations showed slight spectral differences between [TPPZn]+ and [TPPZn(L)]+ but were almost totally insensitive to a specific L. The possibility of an alternate oxidative pathway to the β-substituted pyrrole product was examined and found not to be operative for this time frame and solvent system.