Microwave assisted synthesis of 3-(2,2′-bipyridine-4-yl)-2-propenoic acid ethyl ester

Attaching Photochemically Active Ruthenium Polypyridyl Complex Units to Amorphous Hydrogenated Carbon (a‐C:H) Layers

“…Both pyridine units themselves of course are planar. Nevertheless, the torsional angle between the two pyridine rings amounts to 4.45(3)° in the monoclinic modification of 3 reported herein, whereas it was determined to be 29.98(5)° in case of the orthorhombic modification reported earlier . As a consequence the crystal packing of 3 , which is realized by weak CHO interactions, leads to the formation of infinite planar layers of molecules (Figure b) compared to the observation of infinite waved layers of molecules in the other modification.…”

“…The molecular structure of 3 is depicted in Figure a, for details of the structure analysis see the Experimental Section. Recently, some of us reported an orthorhombic modification of this compound . The molecular structures are almost identical showing the carbon nitrogen bonds in the oxidized pyridine ring to be elongated compared to the situation in the nonsubstituted pyridine entity.…”

“…In a first step 1 is oxidized by means of a mixture of hydrogen peroxide and trifluoro acetic acid to produce 2,2′‐bipyridine‐ N ‐oxide, 2 . The oxidation enhances electron density in the oxidized pyridine ring therefore facilitating the electrophilic substitution reaction using sulphuric acid and potassium nitrate leading to the formation of 4‐nitro‐2‐(pyridin‐2‐yl)pyridine 1‐oxide, 3 . The third reaction step is a reductive coupling of two molecules of 3 which is performed by the use of sodium borohydride catalyzed by palladium on charcoal .…”

“…Therefore, the synthesis of bipyridine ligands comprising acrylic acid ester derived substituents has been intensively studied. The resulting bipyridine compound can be applied as a co‐monomer in the preparation of polyacrylate suspensions, either freely or already in its complexed form . Based on these results, the present synthetic strategy was developed and optimized to produce 4,4′‐azobis‐(2,2′‐bipyridine) ligands.…”

2,2′-Bipyridin-1′-ium 1-oxide bromide monohydrate

“…They are especially well-known for their use in the development of complexes with specific photophysical (Thompson et al, 2013;Sun et al, 2015, Dongare et al, 2017 and/or photocatalytic (Wenger, 2013;Fukuzumi et al, 2016;Knoll et al, 2015;Duan et al, 2015;Pal & Hanan, 2014) properties or for the construction of dye-sensitized solar cells (Happ et al, 2012;Bomben et al, 2012;Robson et al, 2012;Adeloye & Ajibade, 2014;Lu et al, 2016;Omae, 2016). During our attempts to introduce substituents to 2,2 0 -bipyrdines that would allow us to use them as monomers in copolymerization reactions (Heintz et al, 2017), we treated 2,2 0 -bipyridine with a mixture of hydrobromic acid and hydrogen peroxide with the aim of getting direct access to 4-bromo-2,2 0 -bipyridine-1-oxide. After recrystallization, the title compound turned out to be the only isolable product.…”