Metal porphyrin intercalated reduced graphene oxide nanocomposite utilized for electrocatalytic oxygen reduction

In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.

Synthesis of Polymer-Bonded Carbonyl Ruthenium (Ⅱ) and Osmium (Ⅱ) Porphyrins

The reactions of 5- (p-hydroxyphenyl)-10, 15, 20-tris (p-methoxyphenyl) porphyrin(H2Por) 1 respectively with triruthenium dodecacarbonyl [Ru3 (CO)12] and triosmiumdodecacarbonyl [Os3 (CO)12] under N2 gave complexes 2 and 3. Treatment of 2 (and 3) withMerrifield' peptide resin gave 4 (and 5) respectively.

A Convenient Synthetic Method of Metal Dendritic Porphyrins

A convenient synthetic method of metal dendritic porphyrins through the convergent synthetic strategy is described. The porphyrin core were linked with the synthetic fragments by forming ether or ester bonds to give five target compounds were prepared.

Synthesis of Novel Polymer-Bonded Water-Soluble Metal Porphyrins

The reaction of 5, 10, 15, 20-tetra-(4-pyridyl) porphyrin 1 with triruthenium dodecacarbonyl [Ru3(CO)12], zinc(II) acetate, copper(II) acetate, cobalt(II) acetate afforded complexes 2a?2d respectively. Treatment of 2a?2d with Merrifield’s peptide resin obtained 3a?3d. The compounds 3a?3d reacted with methyl iodide respectively gave 4a?4d. New complexes 4a?4d have been identified by IR, UV-visible spectra, and AES.

Synthesis of Polymer-Bonded Quaternary Ammonium Type Metal Porphyrins

The reaction of pyrrole with 4-hydroxybenzaldehyde and 4-pyridinecarboxaldehyde afforded new porphyrin ligand 1. Treatment of 1 with copper( II ) acetate, cobalt ( II ) acetate gave complexes 2-3 respectively. 2 and 3 reacted with Merrifield's peptide resin produced 4 and 5. Complexes 4 and 5 reacted with methyl iodide respectively gave 6-7. The new compounds 1-7 have been identified by H-1 NMR, IR, MS and UV-visible spectra, elemental analysis and AES.

Synthesis of β-Cyclodextrin Bonded Metal Porphyrins

6-Deoxy- 6-iodo-β-cyclodextrin (1) reacted with 5-(p-aminophenyl)-10, 15,20-triphenyl porphyrin(2), 5-(p-aminophenyl)-10,15,20-triphenyl nickel(Ⅱ) porphyrin [NiⅡTPPNH2P](3),5-(p-aminophenyl)-10,15,20-triphenyl manganese(Ⅲ) porphyrin [MnⅢTPPNH2P] (4) and 5-(p-aminophenyl)-10,l5,20-triphenyl carbonyl ruthenium porphyrin [RuⅡ (CO)TPPNH2P] (5) to generate the compounds 6-9, respectively. Those new compound 5-9 have been identified by 1H NMR, IR, MS and UV-visible spectra and elemental analysis.

Distortions and Deformations of Metaled Meso-Substituted and Unsubstituted Porphyrins and Derivatives in Crystal Structures

Experimental crystallographic structural parameters of a range of metaled meso-substituted and unsubstituted porphyrins were reviewed to show how far the meso-substitution by any functional group and the insertion of metal in the porphyrins core macrocycle may affect the geometry. The analysis of twists and angles has shown two kinds of distortions: external [T(Cβ-Cα-Cmeso-Xn) and T(Cβ-Cα-Cmeso-Cα)] and internal [T(Nm-Cα-Cmeso-Xn) and T(Nn-Cα-Cmeso-Cα)] with averages of [+6°and –6°] and [–5°and +5°], respectively. In the meso-substituted case, the external and internal twists Cβ-Cα-Cmeso-X and N-Cα-Cmeso-X, respectively are oppositely orientated. Similar effect is observed in meso-unsubstituted of Cβ-Cα- Cmeso-H and N-Cα-Cmeso-H. However, the external distortions are more significant than internal. Considering the same order, the limit of distortions is [97°and 132°(–48°)] for external and [91°(–89°) and 52°] for internal. In the two cases, the substituents have opposite directions of distortions. The meso-substituted porphyrins have a high limit of twisting than usubstituted one, depending of the weight of substituents. The average of the bond angular deformations is 168°, almost planar. However, the limit of angular deformation is 94°.

Comparing electrocatalytic hydrogen and oxygen evolution activities of first-row transition metal complexes with similar coordination environments

Developing cheap and efficient electrocatalysts for water splitting is required for energy conversion techniques.Many first-row transition metal complexes have been shown to be active for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Metal ions play crucial roles in these catalytic processes,but the activity dependence on the nature of metal ions has been rarely studied due to the difficulty to compare metal complexes with different coordination environments.We herein reported the synthesis of a series of metal complexes of azido-substituted porphyrin(1),in which metal ions have very similar coordination environments.By grafting 1-M(M=Mn,Fe,Co,Ni,and Cu)onto alkynefunctionalized carbon nanotubes(CNTs)through the same covalent connection,the resulted hybrids 1-M@CNT were all active and robust for both electrocatalytic HER and OER in alkaline aqueous solutions.Among these hybrids,1-Fe@CNT displayed the highest electrocatalytic activity for HER,while 1-Co@CNT was the most active one for OER.Moreover,a two-electrode water electrolysis cell assembled with 1-Fe@CNT as the cathode and 1-Co@CNT as the anode required smaller applied bias potential by210 mV to get 10 mA/cm^(2)current density as compared to that assembled with Pt/C and Ir/C with the same amount of metal loading.This work is significant to correlate HER and OER activity with the nature of first-row transition metal ions and to highlight promising potential applications of molecular electrocatalysis in water splitting.

Synthesis and Characterization of β-Cyclodextrin Bonded Metal Porphyrins

Reactions of 5-(p-aminophenyl)-10, 15, 20-triphenyl porphyrin (1) withRu_3(CO)_(12) or M(OCOCH_3)_2 (M= Ni, Mn) afforded metalloporphyrins (4―6), respectively.6-Deoxy-6-io-do-β-cyclodextrin (2) and mono (6-O-trifluoromethanesulfonyl) pennethylatedβ-cyclodextrin (3) reacted with complexes 4―6 to give β-cyclodextrin bonded metal porphyrins(7―9) and permethylated β-cyclodextrin bonded me-tal porphyrins (10―12) respectively. These newcomplexes were identified by MS, IR, UV-visible and ~1H NMR spectra, and elemental analysis.