Synthesis, structure and tautomerism of two benzothiazolyl azo derivatives of 2-naphthol: A crystallographic, NMR and computational study

Racané, Livio; Mihalić, Zlatko; Cerić, Helena; Popović, Jasminka; Tralić‐Kulenović, Vesna

doi:10.1016/j.dyepig.2012.10.009

Cited by 32 publications

(22 citation statements)

References 25 publications

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“…Compound 4 was also studied by NMR concluding that both tautomers a and c were present . The same conclusion was reported for derivative 5 …”

Section: Discussionsupporting

confidence: 69%

“…[54] The same conclusion was reported for derivative 5. [55] A series of papers deal with naphthalene derivatives 6 (a Schiff base) and 7 (an azo compound); by using NMR, the proportion of both tautomers was established [51,56] (in the solid state only, tautomer a was present) [57] ; electronic spectra were used to determine the thermodynamic parameters. In the case of 5, they were ΔH T = À2.5 kJ mol À1 , ΔH T = À9.1 J mol À1 K À1 (ethanol) and ΔH T = À0.8 kJ mol À1 , ΔH T = À22.7 J mol À1 K À1 (methylcyclohexane/toluene).…”

Section: Discussionmentioning

confidence: 99%

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The structures of two aldazines: [1,1′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)dinaphthalen‐2‐ol] (Lumogen) and 2,2′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)diphenol (salicylaldazine) in the solid state and in solution

Silva

Claramunt

et al. 2013

Magnetic Reson in Chemistry

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A combination of NMR spectroscopy and theoretical methods Density functional theory including dispersion corrections (DFT‐D) was used to study the structures of Lumogen and salicylaldazine. In the solid state, Lumogen exists as the dihydroxy tautomer 1a (an azine, CN–NC) as was already known from an X‐ray determination. In a deuterated dimethyl sulfoxide solution, another tautomer is observed besides 1a; its structure corresponds to the hydroxy‐oxo tautomer 1b (a hydrazone, CN–NH–Csp2). In what concerns salicylaldazine, we have observed only the dihydroxy tautomer 2a. Copyright © 2013 John Wiley & Sons, Ltd.

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“…Compound 4 was also studied by NMR concluding that both tautomers a and c were present . The same conclusion was reported for derivative 5 …”

Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

The structures of two aldazines: [1,1′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)dinaphthalen‐2‐ol] (Lumogen) and 2,2′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)diphenol (salicylaldazine) in the solid state and in solution

Silva

Claramunt

et al. 2013

Magnetic Reson in Chemistry

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“…For example, salicylideneaniline ( 1 , Scheme 1 ) derivatives are effective against Mycobacterium tuberculosis H37Rv [ 36 ]. The excited-state intramolecular proton transfer (ESIPT) reaction [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ] of salicylideneaniline derivatives, which incorporates transfer of a hydroxyl proton to the imine nitrogen through a pre-existing intramolecular hydrogen bonding configuration, has also been extensively investigated in the literature [ 55 , 56 ]. As shown in Figure 1 , the resulting proton-transfer tautomer (keto-form) exhibits significant differences in structure and electronic configuration from its corresponding ground state, i.e.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, X-ray Structure, Spectroscopic Properties and DFT Studies of a Novel Schiff Base

Chen

Tsai

2014

IJMS

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A series of Schiff bases, salicylideneaniline derivatives 1–4, was synthesized under mild conditions and characterized by 1H NMR, HRMS, UV-Vis and fluorescence spectra, and single-crystal X-ray diffraction. In solid and aprotic solvents 1–4 exist mainly as E conformers that possess an intramolecular six-membered-ring hydrogen bond. A weak intramolecular C–H···F hydrogen bond is also observed in fluoro-functionalized Schiff base 4, which generates another S(6) ring motif. The C–H···F hydrogen bond further stabilizes its structure and leads it to form a planar configuration. Compounds 1–3 exhibit solely a long-wavelength proton-transfer tautomer emission, while dipole-functionalized Schiff base 4 shows remarkable dual emission originated from the excited-state intramolecular charge transfer (ESICT) and excited-state intramolecular proton transfer (ESIPT) states. Furthermore, the geometric structures, frontier molecular orbitals (MOs) and the potential energy curves for 1–4 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations.

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“…The underlying principle is to monitor the exchange of a proton 16 between two or more forms when the solute molecule undergoes such change. The underlying principle is to monitor the exchange of a proton 16 between two or more forms when the solute molecule undergoes such change.…”

Section: Analyzing Tautomeric Forms Of Azo Dyes Using Selective Technmentioning

confidence: 99%

Spectroscopic studies of keto–enol tautomeric equilibrium of azo dyes

2015

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Synthesis, structure and tautomerism of two benzothiazolyl azo derivatives of 2-naphthol: A crystallographic, NMR and computational study

Cited by 32 publications

References 25 publications

The structures of two aldazines: [1,1′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)dinaphthalen‐2‐ol] (Lumogen) and 2,2′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)diphenol (salicylaldazine) in the solid state and in solution

The structures of two aldazines: [1,1′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)dinaphthalen‐2‐ol] (Lumogen) and 2,2′‐(1E,1′E)‐hydrazine‐1,2‐diylidenebis(methan‐1‐yl‐1‐ylidene)diphenol (salicylaldazine) in the solid state and in solution

Synthesis, X-ray Structure, Spectroscopic Properties and DFT Studies of a Novel Schiff Base

Spectroscopic studies of keto–enol tautomeric equilibrium of azo dyes

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