Synthesis and Characterization of the 4,4′-Bipyridyl Dianion and Radical Monoanion. A Structural Study

Abstract

The reaction of ethylenediamine solutions of 4,4'-bipyridine with varying stoichiometric amounts of sodium resulted in the isolation of the 4,4'-bipyridyl radical anion (44bipy(*-)) and the unprecedented 4,4'-bipyridyl dianion (44bipy(2-)). The radical was characterized by single-crystal X-ray diffraction in Na(44bipy)(en) (1) and Na2(44bipy)2(en)2 (2) and the dianion in Na 2(44bipy)(en)2 (3), allowing for interesting correlations to be drawn between electronic structure and metric structural data. Further characterization of the solids by means of powder X-ray diffraction, electron paramagnetic resonance, and/or elemental analysis is also reported.

Octaboraneyl Complexes of Nickel: Monomers for Redox‐Active Coordination Polymers

“…Treatmento f6 with excessD MAP showcases the lability of these BÀNl inkages, providing ad eepp urple solutiont hat quickly fades to yellow (Scheme 4). Freeze-quenched EPR studies (20 sa fter DMAP addition) evidencest he formation of fragmentsb earing unpairede lectrons, namely free 4,4'-bpy radical anion (which is anecdotally purple) [22] (Figure3D, top);a nnealing this mixture results in rapid radicalq uenching and the formationo f5 and four equivalents of free bipyridine,a sj udged by NMR spectroscopy.Inthis instance,the P 2 B Cy 4 fragment provides au nique opportunity for Lewis base activation,e nabling the facile construction of monomers for incorporation into redox-active coordination polymers-a reversible process.…”

Silicon Containing Nine Atom Clusters from Liquid Ammonia Solution: Crystal Structures of the First Protonated Clusters [HSi9]3– and [H2{Si/Ge}9]2–

“…This assumption is supported by similar observations made in solutions in pyridine, which have been prepared via dissolution in ammonia followed by addition of pyridine and slow evaporation of the ammonia. In such solutions at ambient temperatures decomposition reactions take place indicated by the color change resulting from the well‐known formation of the bipyridinyl radical . This reaction can be avoided by keeping the temperature permanently below –20 °C, and with this condition compounds including undecomposed Si 9 cluster are accessible, e.g.…”

Reduction of 2,2′-Bipyridine by Quasi-Linear 3d-Metal(I) Silylamides—A Structural and Spectroscopic Study

“…Further, it can act as a π-acceptor that can take up one or two electrons to form either the 2,2′-bipyridine radical monoanion [bipy]· − or the diamagnetic dianion [bipy] 2− when subjected to highly reducing agents such as alkaline metals. This has been shown for the alkali metal salts of 2,2′-as well as 4,4′-bipyridine [23,24] and more importantly for 2,2′-bipyridine containing metal complexes [25][26][27][28][29][30][31]. Within these complexes the exact determination of the electronic structure of the [M(bipy)] unit is usually not trivial leading to the generally accepted classification of 2,2′bipyridine as a redox non-innocent ligand [32,33].…”