1761-62-2Relevant articles and documents
Driving the Emission Towards Blue by Controlling the HOMO-LUMO Energy Gap in BF2-Functionalized 2-(Imidazo[1,5-a]pyridin-3-yl)phenols
Colombo, Gioele,Attilio Ardizzoia,Furrer, Julien,Therrien, Bruno,Brenna, Stefano
, p. 12380 - 12387 (2021)
Several boron compounds with 2-(imidazo[1,5-a]pyridin-3-yl)phenols, differentiated by the nature of the substituent (R) in the para position of the hydroxy group, have been synthesized and thoroughly characterized both in solution (1H, 13C, 11B, 19F NMR) and in the solid state (X-ray). All derivatives displayed attractive photophysical properties like very high Stokes shift, high fluorescence quantum yields and a good photostability in solution. Time-Dependent Density Functional Theory (TD-DFT) calculations allowed to define the main electronic transitions as intra ligand transitions (1ILT), which was corroborated by the Natural Transition Orbitals (NTOs) shapes. The HOMO-LUMO energy gap was correlated to the electronic properties of the substituent R on the phenolic ring, as quantified by its σp Hammett constant.
Schiff bases from TRIS and ortho-hydroxyarenecarbaldehydes: Structures and tautomeric equilibria in the solid state and in solution
Martinez, R. Fernando,Uvalos, Martin,Babiano, Reyes,Cintas, Pedro,Jimenez, Jose L.,Light, Mark E.,Palacios, Juan C.
, p. 3137 - 3145 (2011)
Three Schiff bases generated by conventional condensation of a simple aminopolyol (TRIS) and 5-bromo- and 5-iodosalicylaldehyde, and 2-hydroxy-1-naphthaldehyde, have been fully characterized, both in solution and in the solid state. This study provides a
Two-photon fluorescent probes for biological Mg2+ detection based on 7-substituted coumarin
Yin, Haijing,Zhang, Buchang,Yu, Haizhu,Zhu, Lin,Feng, Yan,Zhu, Manzhou,Guo, Qingxiang,Meng, Xiangming
, p. 4306 - 4312 (2015)
Two novel water-soluble coumarin-based compounds (OC7, NC7) were designed and synthesized as two-photon fluorescent probes for biological Mg2+ detection. The compounds feature a β-keto acid as a high selective binding site for Mg2+ a
Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines
Cintas, Pedro,Martínez, R. Fernando,Matamoros, Esther,Palacios, Juan C.
, p. 5838 - 5862 (2020/05/20)
Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of linear free energy relationships (LFER), we disclose how the formation of either imines or enamines can be controlled and provide a comprehensive framework that captures the structural underpinning of this prediction. This work highlights the potentiality of tailor-made designs en route to compounds with desirable functionality.
Nitrostyrene-Modified 2-(2-Hydroxyphenyl)benzothiazole: Enol-Emission Solvatochromism by ESICT-ESIPT and Aggregation-Induced Emission Enhancement
Niu, Yahui,Wang, Rong,Shao, Panlin,Wang, Yuxiu,Zhang, Yanrong
supporting information, p. 16670 - 16676 (2018/10/25)
Excited-state intramolecular charge transfer (ESICT) and excited-state intramolecular proton transfer (ESIPT) are two competitive reactions that occur in the excited states of organic dyes that contain intramolecular hydrogen-bonds and electron acceptors and donors. Determining the mechanisms of these processes is key to understanding their multiple emission features, as the manner in which these processes interact can be modulated by modifying the dye structure. In addition, donor–π–acceptor (D–π–A) molecules often suffer from aggregation-induced quenching. Herein, we report the synthesis of three nitrophenyl-modified 2-(2-hydroxyphenyl)benzothiazole (HBT) derivatives, HBT-s-NO2, HBT-d-NO2, and HBT-t-NO2, which have C?C, C=C, and C≡C bonds between their HBT and nitrophenyl moieties, respectively. Compared with the enol emissions from HBT-s-NO2 and HBT-t-NO2, that from HBT-d-NO2 exhibits outstanding solvatochromism owing to consecutive ESICT-ESIPT. In addition, X-ray diffraction reveals that despite the highly planar and polar nature of HBT-d-NO2, which is strongly H-aggregated, it exhibits highly efficient fluorescence. Hence, this study provides new insight into the design of ESICT/ESIPT-coupled systems and for engendering planar dipolar molecules with excellent emission properties in the solid state.
