NLOphoric mono-azo dyes with negative solvatochromism and in-built ESIPT unit from ethyl 1,3-dihydroxy-2-naphthoate: Estimation of excited state dipole moment and pH study

Warde, Umesh; Sekar, Nagaiyan

doi:10.1016/j.dyepig.2016.10.032

Cited by 36 publications

(10 citation statements)

References 43 publications

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“…The intramolecular hydrogen-bond interactions in the half-salen moieties cause the excited-state intramolecular proton-transfer (ESIPT) [60,61] known to lead to emission in solution [46,59,[61][62][63][64][65][66]. The same effect is known to occur in the solid state [12,67] if the intramolecular H-bond produce hindrance to the torsion of sterically encumbered parts of the molecule [57,68,69].…”

Section: Resultsmentioning

confidence: 99%

A Novel DR/NIR T-Shaped AIEgen: Synthesis and X-Ray Crystal Structure Study

et al. 2020

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We developed a new benzodifuran derivative as the condensation product between 2,6-diamino -4-(4-nitrophenyl)benzo [1,2-b:4,5-b']difuran-3,7-dicarboxylate and 3-hydroxy-2-naphthaldehyde. The intramolecular hydrogen-bond interactions in the terminal half-salen moieties produce a sterically encumbered highly conjugated main plane and a D-A-D (donor-acceptor-donor) T-shaped structure. The novel AIEgen (aggregation-induced enhanced emission generator) fulfils the requirement of RIR (restriction of intramolecular rotation) molecules. DR/NIR (deep red/near infrared) emission was recorded in solution and in the solid state, with a noteworthy photoluminescence quantum yield recorded on the neat crystals which undergo some mechanochromism. The crystal structure study of the probe from data collected at a synchrotron X-ray source shows a main aromatic plane π-stacked in a columnar arrangement.Crystals 2020, 10, 269 2 of 15 law [20][21][22] the intrinsic low band-gap of such DR/NIR emitters makes them especially vulnerable to the ACQ effect [23] due to higher vibrionic coupling between the ground and excited states. Therefore, most of the AIEgens reported emit blue and green lights. Although they are highly sought after for red OLEDs (Organic Light Emitting Diodes), night-vision devices, secured displays, optical waveguides and in the wide field of bio and chemo-sensing [24][25][26][27][28], there are fewer efficient DR/NIR (deep red/near infrared) materials. Of particular interest are AIE fluorophores with intense emission at DR/NIR region owing to their deep tissue penetration, photo-stability and minimum interference in living systems [25,29,30]. Their applications are closely related to cell imaging and DNA and protein sensing [31][32][33].Novel molecular construction of DR/NIR AIEgens can be achieved with electron donor (D) and electron acceptor (A) blocks connected through π-conjugated frameworks. The most fundamental phenomenon governing the spectroscopic properties is the intramolecular charge transfer (ICT) process from the donor to the acceptor in the excited state [34][35][36]. Intercrossed excited state between the low-lying local exciton (LE) and charge transfer (CT) exciton results from the D-A interaction. Obviously, the molecular geometry is crucial for the process.Benzodifuran derivatives have drawn attention for a wide range of biological and pharmacological applications, including antimicrobial, antiviral, analgesic and antitumor [37][38][39][40] activity. This class of heterocyclic compounds are also employed in dyes industry as pigments and in different fields of optoelectronics and photonics. Due to the excellent semiconducting properties [41,42], benzodifuran scaffolds are used as nonlinear optical materials [43], for dye sensitized solar cells [44] and in organic solar cell and transistors. Finally, as electron-rich building blocks they have a potential in the constructing of photoluminescent materials [45][46][47] Herein, we developed a new benzodifuran derivative from 2,6-diamino-4-(4-nitrophenyl) ...

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Section: Resultsmentioning

confidence: 99%

A Novel DR/NIR T-Shaped AIEgen: Synthesis and X-Ray Crystal Structure Study

et al. 2020

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“…The combination of “Self‐Consistent Reaction Field” with the “Polarizable Continuum Model” organized with Gaussian 09 program is used to determine the solvent effect on dyes . Furthermore, we have evaluated linear and NLO properties for dyes 4a–4d such as the static first hyperpolarizability ( β ) and their associated parameters ( μ , α , and γ ) by DFT using GH and RSH functionals with the “6‐311 + G (d)” set . The GH functionals used are B3LYP, PBE0, BHHLYP, MO6, MO6‐L, MO6‐2X, and MO6‐2X.…”

Section: Computational Detailsmentioning

confidence: 99%

Experimental and theoretical investigation of linear and nonlinear optical properties of ethyl‐3‐hydroxy‐2‐napthoate azo dyes by solvatochromic, computational aspects, and Z‐scan technique

Yadav

Taware

Sreenath³

et al. 2020

J of Physical Organic Chem

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To investigate the effect of substituents in azo dyes on their nonlinear optical properties, four azo dyes were synthesized using ethyl‐3‐hydroxy‐2‐naphthoate as a coupler and characterized. The polarizability (α) and hyperpolarizability (β and γ) constants were determined by using solvatochromic and computational method. A group of global hybrid and range seperated hybrid functionals having different Hartree‐Fock exchange percentage were used to evaluate the NLO properties. The functional ωB97 and ωB97XD performed better in the determination of polarizability (α) and hyperpolarizability (β and γ), respectively. The observed results for polarizability and hyperpolarizability parameters were supported by highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) energy gap, Hammett‐coefficient (σ), excited‐state coefficients (σex), and hyper‐hardness (Γ) values. Third‐order NLO properties were analyzed by using Z‐scan technique. The –OCH3 substituted dye 4d shows higher value of molecular susceptibility (χ(3)), polarizability (α), and hyperpolarizability (β and γ) parameters among the studied azo dyes. They are likely to have the potential applications in optoelectronics and photonics.

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“…Recently, effect of viscosity on fluctuating emission properties of some of the organic dyes were provided and studied in the literature [39,40], however, only few reports were based on viscosity effects on the properties of azo dyes [20,41,42]. Intramolecular rotation in azo dyes are restricted due to either chemical interaction or adhesion of dyes on fabrics during dyeing [43,44].…”

Section: Introductionmentioning

confidence: 99%

“…To meet the requirements of fluorescent disperse dyes with excellent fastness properties, we used the key ingredient benzophenone which acts as a UV stabilizer and it has its own emission, which facilitate to prepare photostable fluorescent dyes. As azo (-N=N-) moiety in azo dyes reduce the fluorescent properties because of photoisomerisation [46,47] and other dynamics such as excimer or exciplex formation may be contribute to reduce fluorescence [39,48]. So, to avoid these process and increase fluorescence one can use micro-viscosity as a strategy to make molecule more rigid and restrict its rotations.…”

Section: Introductionmentioning

confidence: 99%