Selective Formation of Conductive Network by Radical-Induced Oxidation

Abstract

Cd-based coordination networks having channels were formed selectively by using a redox-active aromatic ligand 2,5,8-tri(4-pyridyl)1,3-diazaphenalene (TPDAP, H(+)1(-)). An electron-conductive network having a π-π stacking columnar structure of TPDAP formed in the presence of a trace amount of TPDAP radical (1(•)). In contrast, a nonconductive network having a dimer unit of H(+)1(-) formed in the absence of 1(•). These results suggest the presence of a unique oxidation mechanism of TPDAP induced by formation of H(+)1(-)-1(•) dimer, which was initiated by a trace amount of 1(•). The dimerization increased HOMO level of H(+)1(-) moiety within the dimer to generate further radicals that could not form when H(+)1(-) was well isolated in CH3OH.

An Organic Mixed‐Valence Ligand for Multistate Redox‐Active Coordination Networks

“…Herein, we report the synthesis and properties of a multi‐interacting ligand capable of generating MV states and forming a three‐dimensional (3D) redox‐active coordination network. We designed the interactive ligand 5,5′,8,8′‐tetra(4‐pyridyl)‐2,2′‐(1,4‐phenylene)bis‐1 H ‐perimidine (H 2 TPP) based on the redox‐active diazaphenalenyl (DAP) group, as we have already successfully prepared TPDAP (Figure ), which shows two redox couples in the solid state and forms a conductive Cd‐TPDAP coordination network …”

Redox Active Metal– and Covalent Organic Frameworks for Energy Storage: Balancing Porosity and Electrical Conductivity

“…The increase of conductivity is contributed by the loosely bound Fe 2+ β‐spin electron. Kawano's group reported a Cd‐TPDAP (TPDAP=2,5,8‐tri(4‐pyridyl)‐1,3‐diazaphenalene) framework and the introduction of trace amounts of TPDAP radical resulted in an increase of conductivity from negligible to 10 −6 S cm −1 . Both methods discussed are based on MOFs of low porosities and although the improvements in conductivity were significant, it still does not meet the minimum requirements for energy storage applications.…”

“…Kawano's group reported a Cd-TPDAP (TPDAP = 2,5,8-tri(4-pyridyl)-1,3-diazaphenalene) framework andt he introductiono ft race amountso fT PDAP radicalr esulted in ani ncreaseo fc onductivity from negligible to 10 À6 Scm À1 . [32] Both methods discussed are based on MOFs of low porosities and although the improvements in conductivity were significant, it still does not meet the minimumr equirements for energy storagea pplications. Af acile doping processc ould be appliedt oc urrent materials to achieve abalance between optimal porosity and elec-trical conductivity of MOFs because both factors are important for the potential electrode material.…”

Control of anisotropy of a redox-active molecule-based film leads to non-volatile resistive switching memory

“…1a). 7,8 This molecule is comprised of a redox active DAP skeleton 9,10 and three pyridyl moieties so that it can be used to form redox active coordination networks. Indeed, self-assembly of this molecule with Cd 2+ produces a p-p columnar structure of DAP to create an electron transfer path only when the molecule is partially oxidized.…”

“…Indeed, self-assembly of this molecule with Cd 2+ produces a p-p columnar structure of DAP to create an electron transfer path only when the molecule is partially oxidized. 8 This fact encouraged us to utilize the DAP derivative for further applications. Because the oxidation of the Cd coordination network increases electron conductivity, it indicates that the conductive and nonconductive (insulating) properties in the solid state can be switched by redox state change (applying voltage) using an anisotropic p-p columnar electron transfer path of DAP.…”