Biologically significant pyrimidine appended optical sensors: An inclusive anthology of literature from 2005 to 2020

Protonation of cyclen-based chelating agents containing fluorescent moieties

“…With this in mind, in this paper we report on a series of potential chemosensors containing a 1,4,8,11tetraazacyclododecane (cyclen) moiety, 7,[49][50][51][52] one of the most used binding unit, with appended one or two equal or different signalling moieties (L1-H 2 L5 in Scheme 1). In this respect, we have chosen two 'classic' signalling moieties, e.g., quinoline (Q), [53][54][55][56] which contains a weakly basic heteroaromatic nitrogen and 8-hydroxyquinoline (8-OH-Q), [57][58][59][60][61] featuring a weakly acid hydroxyl group close to a protonable nitrogen. We have also introduced in this study receptor H 2 L5 containing two carboxylate groups appended to the polyamine framework.…”

4,6-Bis((E)-2-(4′-N,N-diphenylamino-[1,1′-biphenyl]-4-yl)vinyl)-2-phenylpyrimidine

“…The pyrimidine heterocycle is a six-membered aromatic ring with two nitrogen atoms in positions 1 and 3. Due to its π-deficient character, this heterocycle can be used as the electron-withdrawing part in push-pull structures [2] and the electron-lone pairs of the two nitrogen atoms are available for protonation, complexation and formation of hydrogen bonds, enabling us to tune the electron-withdrawing strength of this core [2,3]. Pyrimidine chromophores have been extensively used as fluorescent sensors for acidity [4], polarity [5], metal cations [6] or nitro-aromatic explosives [7].…”