Is it possible to switch ESIPT-channel of hydroxyanthraquinones with the strategy of modifying electronic groups?

Dual emission of ESIPT-capable 2-(2-hydroxyphenyl)-4-(1H-pyrazol-1-yl)pyrimidines: interplay of fluorescence and phosphorescence

“…Electronic properties of ESIPT-capable molecules and therefore the ESIPT and GSIPT abilities of such molecules can be tuned through introducing various substituents or heteroatoms, 16–36 expanding the π-system, 37–40 binding metal ions, 41–54 protonation/deprotonation, 55–64 solvent effects, 65–69 etc. The synthetic flexibility of such molecules is based on established synthetic methods of organic chemistry and provides researchers with almost unlimited options for the rational design and modification of various ESIPT-capable scaffolds.…”

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

“…105,106,119 It is well known that the proton transfer abilities and emission properties of ESIPT-capable molecules can be tuned by substitution on the proton-donating and protonaccepting cores, as well as by the degree of π-conjugation. [120][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136] As far as the degree of π-conjugation is concerned, extending the π-conjugated system on the protondonating part of the molecule can frustrate the ESIPT process, since the excited state is located predominantly on the ESIPT-incapable part of the molecule and involves the ESIPT site only to a small extent. 135,136 Instead, the extension of the π-conjugated system on the proton-accepting moiety could facilitate the ESIPT process due to better delocalization of a positive charge.…”

ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence

“…The ESIPT photoreaction ( Scheme 1 ) is highly sensitive to substituents [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] and coordinated metal ions [ 28 , 29 , 30 , 31 , 32 , 33 ], protonation/deprotonation [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ], the state of aggregation [ 42 , 43 ], the polarity of solvent [ 44 , 45 , 46 , 47 , 48 ] and the presence of various analytes [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. If the excited state tautomerization (normal-to-tautomeric) is barrierless, the only form to emit is the tautomeric one, which typically luminesces with rather large Stokes shift [ 57 , 58 ].…”