Synthesis and Redox Properties of PNP Pincer Complexes Based on N‐Methyl‐4,4′‐bipyridinium

Abstract

Keywords: Photocatalysis / Electron transfer / Dihydrogen / Ligand design / MetalloviologensWe have designed and prepared a series of novel PNP pincer ligands based on N-methyl-4,4Ј-bipyridinium for the construction of stable complexes toward two steps of single electron transfer reactions, where p-quinoid-type complexes play a key role. Electrochemical studies reveal that two reduction waves of these complexes are similar to those of methylviol-

Stable Nickel(I) Complexes with Electron-Rich, Sterically-Hindered, Innocent PNP Pincer Ligands

“…The bulky PNP ligands were synthesized by modification of the synthetic procedure for the previously reported unsubstituted PNP R BH 3 ligands (R = i Pr, t Bu), 97 which also differs from a procedure for similar previously reported methylated ligands. 98 They were then reacted subsequently with n-butyl lithium and methyl iodide multiple times (Scheme 1) to afford the fully methylated Me 4 PNP R BH 3 ligands in 83−85% yields.…”

Fe-doped phosphorene for the nitrogen reduction reaction

“…[10][11][12][13][14] In contrast, the biological N2-fixation, under ambient conditions, through the nitrogen-binding enzymes called nitrogenases to activate the N-N bond of N2. 4,11,[15][16][17][18][19][20] It is essential that the nitrogen fixations through the catalysts of nitrogenases undergo six sequential process of protonation and electron transfers. In addition, the N-N triple bond of N2 have been not cleavaged to adatoms at the first step of the reduction process.…”

Design and Synthesis of Tunable Ligands with 4,4′-Bipyridyl as an Electron-Accepting Unit and Their Rhenium Complexes

“…Interactions between metallic centers and π-conjugated 4,4′-bipyridyl systems have been expected to enable intriguing optical and magnetic properties and to promote unique reactions. − Recently, we have prepared novel PNP pincer complexes based on N -methyl-4,4′-bipyridinium to obtain stable complexes toward two-step single-electron-transfer reactions (Scheme b). We have applied them to photocatalytic dihydrogen production . As an extension of our study, we have synthesized a series of rhenium complexes 2 bearing a 4,4′-bipyridyl skeleton as novel “metalloviologens” (Scheme c).…”

“…We have applied them to photocatalytic dihydrogen production. 11 As an extension of our study, we have synthesized a series of rhenium complexes 2 bearing a 4,4′bipyridyl skeleton as novel "metalloviologens" (Scheme 1c). In order to enhance the tunability of the complexes, we have designed 2 to separately assign the role as an electron acceptor to the 4,4′-bipyridyl core and the role as a coordination site to D, which modifies the electronic nature of the rhenium center.…”