TY - JOUR

T1 - Proton-induced fluorescence in modified quino[7,8-h]quinolines

T2 - dual sensing for protons and pi-donors

AU - Pozharskii, Alexander F.

AU - Ozeryanskii, Valery A.

AU - Mikshiev, Vladimir Y.

AU - Chernyshev, Anatoly V.

AU - Metelitsa, Anatoly V.

AU - Antonov, Alexander S.

N1 - Publisher Copyright: © 2019 The Royal Society of Chemistry.

PY - 2019/9/21

Y1 - 2019/9/21

N2 - The synthesis, as well as spectral, structural and photoluminescence properties of dipyrido[3,2-e:2',3'-h]acenaphthene 5 and quinazolino[7,8-h]quinazolines 6 as representatives of the bidentate -N[double bond, length as m-dash]/-N[double bond, length as m-dash] superbases, are reported. These nitrogen bases being more rigid (5) or π-extended (6) analogs of optically-mute quino[7,8-h]quinoline are both active in terms of fluorescence with quantum yields up to φ = 0.71-0.77. At the same time, their luminescence behavior is opposite to that of peri-NMe2/NMe2 naphthalene proton sponges and their hybrid NMe2/-N[double bond, length as m-dash] analogs. Although 5 and 6 exhibit visible region emission upon protonation, for the hybrid systems the fluorescence is manifested only for bases. The most remarkable observation is that the fluorescence of compound 5 can be switched on not only by means of organic or inorganic acids, but also through the formation of chelate complexes with such weak H-donors as water and primary alcohols. It was disclosed that water is present in the complex as a cluster comprising 8 interconnected H2O molecules. Overall, the studied compounds demonstrate a previously unobserved type of dual mode optical response, H-sensing (emission enhancement in 5 and 6 on protonation) and π-sensing (emission quenching in 5H+ and 6H+ on coordination with π-donors). This work seems to be an important contribution to areas such as chemosensorics, the creation of new ligands, hydrogen transfer and some other phenomena representing different types of supramolecular interactions.

AB - The synthesis, as well as spectral, structural and photoluminescence properties of dipyrido[3,2-e:2',3'-h]acenaphthene 5 and quinazolino[7,8-h]quinazolines 6 as representatives of the bidentate -N[double bond, length as m-dash]/-N[double bond, length as m-dash] superbases, are reported. These nitrogen bases being more rigid (5) or π-extended (6) analogs of optically-mute quino[7,8-h]quinoline are both active in terms of fluorescence with quantum yields up to φ = 0.71-0.77. At the same time, their luminescence behavior is opposite to that of peri-NMe2/NMe2 naphthalene proton sponges and their hybrid NMe2/-N[double bond, length as m-dash] analogs. Although 5 and 6 exhibit visible region emission upon protonation, for the hybrid systems the fluorescence is manifested only for bases. The most remarkable observation is that the fluorescence of compound 5 can be switched on not only by means of organic or inorganic acids, but also through the formation of chelate complexes with such weak H-donors as water and primary alcohols. It was disclosed that water is present in the complex as a cluster comprising 8 interconnected H2O molecules. Overall, the studied compounds demonstrate a previously unobserved type of dual mode optical response, H-sensing (emission enhancement in 5 and 6 on protonation) and π-sensing (emission quenching in 5H+ and 6H+ on coordination with π-donors). This work seems to be an important contribution to areas such as chemosensorics, the creation of new ligands, hydrogen transfer and some other phenomena representing different types of supramolecular interactions.

KW - HYDROGEN-BONDS

KW - H-BOND

KW - SPONGES

KW - COMPLEXES

KW - QUINOLINE

KW - GEOMETRY

KW - CRYSTAL

KW - ANALOGS

KW - CLUSTER

UR - http://www.scopus.com/inward/record.url?scp=85072057743&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/protoninduced-fluorescence-modified-quino78-h-quinolines-dual-sensing-protons-%CF%80donors

U2 - 10.1039/c9ob01391a

DO - 10.1039/c9ob01391a

M3 - Article

C2 - 31436774

AN - SCOPUS:85072057743

VL - 17

SP - 8221

EP - 8233

JO - Organic and Biomolecular Chemistry

JF - Organic and Biomolecular Chemistry

SN - 1477-0520

IS - 35

ER -