One-Pot Synthesis of Squaraine Fluoroionophores

Oguz, Umut; Akkaya, Engin U.

doi:10.1021/jo9805145

Cited by 22 publications

(10 citation statements)

References 14 publications

(15 reference statements)

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“…Briefly, SQ 1 was prepared from the condensation of electron‐rich D with squaric acid using a Dean–Stark apparatus, where the water that formed was removed continuously. [7b], Intermediate B was synthesized from A and triethylene glycol monomethyl ether based on the Steglich esterification reaction . Then C was obtained using trifluoroacetic acid (TFA) to remove the tert ‐butyloxycarbonyl protecting group in B , followed by the general reaction of phloroglucinol with the resultant secondary amine through its keto tautomer in 1‐butanol/toluene mixture under reflux.…”

Section: Methodsmentioning

confidence: 99%

Far‐Red‐Emitting TEG‐Substituted Squaraine Dye: Synthesis, Optical Properties, and Selective Detection of Cyanide in Aqueous Solution

Liu

Valencia

et al. 2017

Eur J Org Chem

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A comprehensive study of the photophysical properties of triethylene glycol monomethyl ether (TEG)‐substituted squaraine dye SQ1 is presented. SQ1 exhibits strong absorption and intense fluorescence emission in the far‐red spectral region and high photostability. Interestingly, bis‐tegylated SQ1 was characterized to exhibit properties different from its tetrahydroxy analog (SQ2), to which we ascribe attenuation of intermolecular interactions as a result of steric hindrance through introduction of two TEG chains adjacent to the squaraine core. The photophysical properties of SQ1 were also investigated as a function of temperature and pH. In cetyltrimethylammonium bromide (CTAB) micellar media (1.0 mm), the fluorescence quantum yield of SQ1 increased dramatically to 0.22, compared with 0.02 in water. Based on this discovery, SQ1 was found to display excellent sensitivity and selectivity to the presence of cyanide ions (CN–), with a limit of detection of 1.7 µm. The hypothesized CN– sensing mechanism was probed, and visual test strips were developed. This work broadens the family of squaraine dyes and demonstrates SQ1 for use as a fluorescent or visual sensing probe.

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Section: Methodsmentioning

confidence: 99%

Far‐Red‐Emitting TEG‐Substituted Squaraine Dye: Synthesis, Optical Properties, and Selective Detection of Cyanide in Aqueous Solution

Liu

Valencia

et al. 2017

Eur J Org Chem

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“…Similar spectral changes were noted when the Mg 2+ -SQS4 complex was allowed to equilibrate overnight. As a follow-up, a more detailed procedure for SQS4, as well as a 1-aza-15-crown-5-containing squaraine, SQS5, which should, in principle, have high affinity towards smaller-sized ions, such as Li+, for example, was also reported (albeit no binding studies were disclosed) [60]. Scheme 4.…”

Section: Crown Ether-containing Squaraine Sensorsmentioning

confidence: 99%

Squaraine-Based Optical Sensors: Designer Toolbox for Exploring Ionic and Molecular Recognitions

Dzyuba

2021

Chemosensors

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Small molecule-based chromogenic and fluorogenic probes play an indispensable role in many sensing applications. Ideal optical chemosensors should provide selectivity and sensitivity towards a variety of analytes. Synthetic accessibility and attractive photophysical properties have made squaraine dyes an enticing platform for the development of chemosensors. This review highlights the versatility of modular assemblies of squaraine-based chemosensors and chemodosimeters that take advantage of the availability of various structurally and functionally diverse recognition motifs, as well as utilizing additional recognition capabilities due to the unique structural features of the squaraine ring.

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“…5b 2g (HOMO-1!LUMO) single-excitations, which however, Table 5. Description of states in terms of dominant electronic configurations/amplitudes (only the part differing from the GS or reference state is reported) is given for CAM-B3LYP, CC2, EOM-CCSD, ADC(2) and ADC (3). For all methods, assignments refer to HF MOs depicted in Figure 3 according to CASPT2, ADC(3) and CI-MRPT2 are strongly mixed with the, 6b 2 3u !5b 2 2g (HOMO 2 !LUMO 2 ) double excitation.…”

Section: Assignment Of the Relevant Statesmentioning

confidence: 99%

“…Squaraine dyes are obtained from the condensation of squaric acid with aromatic or heterocyclic components, [1,2] and are usually considered as donor-acceptor-donor (DÀ A-D) systems where the oxocyclobutenolate acts as the acceptor core. In the last decades, they have attracted large interest for different applications as solar cell dyes, [3][4][5][6][7] fluorescent probes, [8,9] photosensitizers for photodynamic therapy, [10][11][12] and nonlinear optical chromophores. [13][14][15][16][17][18][19][20] Figure 1 reports the structure of the simple squaraine dye that will be studied in this contribution, since now on referred to as SQ0.…”

Section: Introductionmentioning

confidence: 99%

The Intriguing Case of the One‐Photon and Two‐Photon Absorption of a Prototypical Symmetric Squaraine: Comparison of TDDFT and Wave‐Function Methods

et al. 2019

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We face the challenging description of the excited states responsible for one photon (OPA) and two photon (TPA) absorption in squaraine dyes, adopting both time-dependent density functional theory and a large variety of post Hartree Fock methods, including coupled cluster and adiabatic diagrammatic construction methods (ADC, to the second and third order), symmetry adapted cluster configuration interaction (CI), CASSCF including second-order perturbative corrections (PT2) with standard CASPT2 recipe and according to n-electron valence PT2 (NEVPT2) approach, and an additional multireference CI with PT2 corrections (CI-MRPT2). We selected a small prototypical symmetric squaraine dye for which these accurate computations are feasible and experimental data are available.We show that while all methods reasonably reproduce the OPA spectrum, an acceptable description and assignment of the states responsible for TPA is only possible through ADC(3) and multireference calculations, due to the strong involvement of double-excitations. The nature of ground state and OPA and TPA states is investigated with a rigorous reading of the CASSCF wavefunctions in terms of localized molecular orbitals on the donor and acceptor fragments, showing that these states arise from a balance of many different contributions including biradical configurations, local excitations and charge-transfer states where both side aromatic rings and the carbonyls of the squarylium moiety act as donors.[a] Dr.

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One-Pot Synthesis of Squaraine Fluoroionophores

Cited by 22 publications

References 14 publications

Far‐Red‐Emitting TEG‐Substituted Squaraine Dye: Synthesis, Optical Properties, and Selective Detection of Cyanide in Aqueous Solution

Far‐Red‐Emitting TEG‐Substituted Squaraine Dye: Synthesis, Optical Properties, and Selective Detection of Cyanide in Aqueous Solution

Squaraine-Based Optical Sensors: Designer Toolbox for Exploring Ionic and Molecular Recognitions

The Intriguing Case of the One‐Photon and Two‐Photon Absorption of a Prototypical Symmetric Squaraine: Comparison of TDDFT and Wave‐Function Methods

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