coumarin - ACS Publications - American Chemical Society

Page 1 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

Photophysics of Derivatives of 3-Hydroxybenzo[c]coumarin Irena Deperasińska,a Artur Makarewicz,a Maciej Krzeszewski,b Daniel T. Gryko*b and Boleslaw Kozankiewicz*a a

Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland E-mail: [email protected]

b

Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44/52, 01-224 Warsaw, Poland E-mail: [email protected]

Keywords: coumarins, hydrogen bond, DFT-calculations, fluorescence, ESIPT

Abstract The photophysical studies of two phenols, derivatives of 3-hydroxybenzo[c]coumarin, were performed in n-nonane matrix at 5 K. Unstructured fluorescence spectrum of the derivative bearing a salicylaldehyde moiety, whose onset is shifted by ca. 3000 cm-1 to lower energy in respect to that of absorption, and short decay time of this emission (0.75 ns) suggested the occurrence of excited-state intramolecular proton transfer (ESIPT). The experimental results were interpreted with the aid of quantum chemistry calculations performed with the DFT and TDDFT/B3LYP/6-31++G(d,p) methods.

1. Introduction Coumarins are well-known heterocycles,1 which have been extensively explored for various photonic applications,2-6 including use as fluorescence probes,7,8 optical brighteners,9 and as emitter layers in organic light emitting diodes (OLEDs).10,11 They have also been successfully incorporated into energy- and electron-transfer arrays12,13 and have served as initiators in two-photon polymerization.14

Because of their importance, many synthetic

strategies have been developed for the preparation of coumarins.15-20 Although the first π1 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

expanded coumarins were synthesized by Pechmann in 1884,21 it was not until recently that this field started to burgeon. Numerous new types of π-expanded coumarins have been synthesized in the last decade.22-28 Ahn and co-workers recently revealed the superb optical properties of benzo[g]coumarins and employed them in fluorescence imaging.29,30 Although coumarins have attracted attention for 100 years,1,21 their optical properties are still puzzling the researchers.31 In particular, benzo[c]coumarins, have not been the subject of in-depth exploration. Motivated by the current interest in fluorescent probes, we have focused our studies on the derivatives of benzo[c]coumarins in order to gain in-depth understanding of their optical properties. In the present contribution, we have concentrated on 2-hexyl-3hydroxybenzo[c]coumarin (1)32 and analogous 4-formyl-2-hexyl-3-hydroxybenzo[c]coumarin (2)33 (Figure 1).

Figure 1. The structures of benzo[c]coumarins 1 and 2.

From a formal point of view, compound 1 can be considered as the π-expansion of 7hydroxycoumarins (umbelliferone),34-47 whereas compound 2 corresponds to the π-expansion of 8-formyl-7-hydroxycoumarin.48,49 Aldehyde 2 can also be considered as a derivative of 1, with the CHO group substituted in the 4 position (position numbering as in Fig. 1 of ref. [32]). The rationale behind the presence of hexyl groups is reaching a reasonable solubility in nonpolar solvents. Earlier investigations of the structure of the electronic spectra of umbelliferone are widely represented in the literature.35, 40-47 A detailed understanding of its photophysics is still a challenge.36 Issues that remain to be clarified are the consequences of the proximity of nπ* and ππ* states,50 and the recently postulated mechanism of the radiationless deactivation of the excitation energy by the opening of the umbelliferone ring.36 The only paper which deals with 8-formyl-7-hydroxycoumarin was dedicated to a cyanide-chemosensing mechanism, which was based on the transfer of protons in the electronic ground and excited states in the intermolecular hydrogen bonding.48,49 The spectroscopic studies of coumarins are difficult because of the possible coexistence of several ionic and tautomeric forms,35,40,41,42,47 the change of acidity during the 2 ACS Paragon Plus Environment

Page 2 of 23

Page 3 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


electronic excitation,45 or the formation and interaction of complexes with the solvent molecules.41-44,47

To avoid such difficulties, in the present work we performed the

spectroscopic (fluorescence and phosphorescence spectra) and kinetic (emission decays) studies in a nonpolar n-nonane matrix at 5 K. The experimental results were supported by the quantum chemistry calculations with the aid of DFT and TDDFT B3LYP/6-31++G(d,p) methods.51

2 Experimental Compounds 1 and 2 were prepared as previously reported.32,33 N-nonane (SigmaAldrich ReagentPlus) was used as received. Samples, ∼10-5 M solution of 1 or 2 in n-nonane, were poured into a quartz cuvette and quickly frozen in liquid nitrogen just before being inserted into a cryostat. Absorption spectra (at 5 K) were recorded in a single-beam configuration using a homemade cuvette in which a solution was frozen between two quartz windows separated by a 1.5 mm Teflon ring. The light from a xenon lamp transmitted through the sample was dispersed with a McPherson 207 monochromator and detected with an EMI96659 photomultiplier operating in photon counting mode. Fluorescence and phosphorescence spectra in solid matrices at 5 K were measured in a right angle configuration. Samples were excited either by using 308 nm light emitted by a Lambda Physics LPX100 excimer laser (repetition rate 10 Hz, pulse duration 15 ns) or 355 nm light provided by the second harmonic of a mode-locked Coherent Mira-HP femtosecond laser pumped by a Verdi 18 laser (repetition rate 80 MHz, pulse width ∼200 fs). Fluorescence photons were dispersed with a McPherson 207 monochromator (300 G/mm) and detected by an Andor DU420A-BR-DD CCD camera, electronically cooled to -90 degree Celsius. The phosphorescence spectrum (λexc= 355 nm) was separated with the aid of two choppers, the first in the excitation and the second in the emission path.52 Phosphorescence decay was obtained with excitation light blocked by a third chopper and photons were detected by an EMI 9659 photomultiplier and cumulated with the aid of a Stanford SR430 Multi-Channel Scaler.52 Fluorescence decays were measured with the aid of "time correlated" single photon counting technique (in the inverted time mode). Excitation pulses were provided by the second harmonic of a mode-locked Coherent Mira-HP femtosecond laser pumped by a Verdi 18 laser. Original repetition rate of a Mira laser was reduced with the aid of an APE Pulse 3 ACS Paragon Plus Environment


selector to 2 MHz. Fluorescence photons, dispersed with a McPherson 207 monochromator, were detected with a HMP-100-50 hybrid detector and a SPC-150 module inserted into a PC, both from Becker&Hickl GmbH. Fluorescence decays (see Fig. S1 of ESI) were fitted to single exponential dependencies without using a deconvolution procedure.

Estimated

precision of the determination of the decay time was 10 ps. All calculations were performed with aid of the Gaussian 09 package.51 Optimization of the molecular geometry in the electronic ground (S0) and lowest excited (S1) states were obtained with the DFT and TD DFT B3LYP/6-31++G(d,p) methods. The transition energies for molecules in solutions were calculated with the use of a simple polarizable-continuum model (PCM) included in the Gaussian package. Vibrational structures of the electronic spectra was calculated with a procedure included in Gaussian 09, which used the FranckCondon factors and the Duchinsky matrix.53,54

3. Results and discussion 3.1 Absorption and fluorescence spectroscopic results Description of the synthesis and preliminary information about the absorption and fluorescence spectra (and quantum yields of the emission) of compounds 1 and 2 in liquid solutions at room temperature have been previously reported.32 Both compounds appeared to have broad, unstructured fluorescence bands with large Stokes shifts with respect to the absorption, and their fluorescence quantum yields were rather low. Absorption and emission spectra of compounds 1 and 2 in n-nonane matrixes at 5 K are presented in Fig. 2.

0.5 [a. u.] absorbance

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 23

2000

x10 0.0

0 30000

20000

4 ACS Paragon Plus Environment

-1

ν [cm ]

Page 5 of 23

[a. u.]

0.5

3000 absorbance

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


2000

1000

0.0 30000

20000

-1

ν [cm ]

Figure 2. Absorption (black) and fluorescence (λexc= 355 nm, blue) spectra of compounds 1 (upper panel) and 2 (lower panel) in n-nonane matrixes at 5 K. Phosphorescence spectrum of 1 (λexc= 355 nm, red) was obtained with the aid of excitation and emission choppers operating in "out-off-phase" position. Imperfect removal of phosphorescence resulted in some weak structure in the fluorescence spectrum of compound 1. The sharp line at 28170 cm-1 indicated the excitation frequency (λexc= 355 nm). The absorption spectrum of compound 1 in n-nonane at 5 K was composed of broad, unstructured bands. The lowest energy band had a maximum at ~29400 cm-1 and an onset at 26300 cm-1. The spectrum resembled the room temperature spectrum of 1 in acetonitrile, with the low energy band located at 30120 cm-1, as previously reported.32 The broad fluorescence band of 1 in n-nonane at 5 K has a maximum at about 22500 cm-1 (23040 cm-1 in acetonitrile at room temperature)32 with high energy onset at 26200 cm-1. Coincidence of the onsets of the absorption and fluorescence bands allow us to locate the (0, 0) transition at ∼26250 cm-1. Fluorescence decay curves were measured at three different observation wavelengths, see ESI, Fig. S1. Decays were well fitted to single exponential dependences but with the decay times slightly dependent on the observation wavelength. The decay time (τfl) obtained at the high energy side of the fluorescence band (25000 cm-1) was 2.50 ns. With the band maximum of 22200 cm-1, the decay time was 2.64 ns, while at the low energy side (20000 cm-1), the decay time was extended to 2.89 ns.

The wavelength

dependence of the decay times suggested a distribution of matrix sites occupied by different guest molecules. 5 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 23

Assuming that the fluorescence quantum yield (Φfl) at 5 K is the same as that at room temperature (i.e. 0.18),32 we calculated that the radiative rate constant (kr= Φfl/τfl) would be 0.68·108 [s-1], whereas the nonradiative value would be knr = 3.11·108 [s-1]. In contrast to the room temperature observation,32 in addition to fluorescence emission, at 5 K we also detected phosphorescence. This emission has slightly resolved vibronic structure, with the highest energy (0,0) band at 22520 cm-1 and the vibronic frequencies of 730, 1550 and 2880 cm-1. The high energy onset of phosphorescence was located at ∼22820 cm-1. The decay time of this phosphorescence emission was very long, 1.66 sec.

Observation of phosphorescence of coumarins at low temperatures is a

characteristic feature for this group of dyes. For example, phosphorescence with the (0, 0) peak at 21410 cm-1, and a lifetime of 1.1 sec, has been previously reported for 7hydroxycoumarin in an ethanol matrix at 77 K.46 The absorption spectrum of compound 2 in n-nonane at 5 K was composed of two broad bands. The lowest energy band had its maximum at 25900 cm-1, with the onset at 23200 cm-1. This band in acetonitrile at room temperature had a maximum at 24940 cm-1.32 The broad, unstructured fluorescence of aldehyde 2 in n-nonane was shifted to the low energy region and it did not have a common onset point with the absorption.

The

-1

fluorescence emission maximum was located at 17500 cm , while the high energy onset was located at 20450 cm-1. Such a broad absorption-fluorescence separation clearly indicated a large difference between the absorbing and emitting species of the molecule, a characteristic feature of excited state intramolecular proton transfer (ESIPT).48,49,55-58 This phenomenon is attributed to the presence of intramolecular hydrogen bond between OH group and CHO substituent located at the neighboring position. The fluorescence emission decayed much more rapidly than that for compound 1 (see ESI). The decay times were 0.8, 0.75, and 0.71 ns, for the fluorescence emission observations at 18180, 16670 and 15380 cm-1, respectively. The wavelength dependence indicated, as in the case of compound 1, a distribution of matrix sites with slightly different lifetimes. Assuming that Φfl at 5 K for compound 2 was the same as that at room temperature (i.e. 0.05),32 we calculated the value of the radiative rate constant as 0.67·108 [s-1] (very much similar to that of compound 1), whereas the nonradiative knr = 12.6·108 [s-1].

Thus,

depopulation of the S1 state in compound 2 proceeded mainly by a nonradiative channel, and the absence of phosphorescence suggested domination of relaxation by an internal conversion process.


Page 7 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


3.2 Quantum chemistry calculations and discussion The aim of the quantum chemistry calculations was to obtain complementary information about the character of experimentally observed electronic transitions and possible paths of relaxation of the excitation energy in the investigated compounds. Due to the time-consuming optimization of the molecular structures in the excited state S1 majority of calculations were performed for isolated molecules lacking the hexyl chain. In order to estimate the error connected with such the simplification we first performed calculations of the transition energies and oscillator strengths for the molecular structures optimized in the ground S0 state. The calculated data and the experimental (exp.) maxima of absorption bands are presented in Table 1. It is seen that the removal of the hexyl chain leads to overestimation of the transition energies by ca. 1000 - 2000 cm-1, and slight decrease of the oscillator strength.

Table 1. Comparison of the calculated energies and oscillator strengths (f) of the S0 → S1 transitions for molecules 1 and 2 with and without a hexyl group, isolated and in nnonane environment.

1

isolated

30959 cm-1, f = 0.1687

31453 cm-1, f = 0.1417

in n-nonane

30331 cm-1, f = 0.2376

30827 cm-1, f = 0.2136

exp. in n-nonane

2

29400 cm-1

isolated

27206 cm-1, f = 0.0829

27948 cm-1, f = 0.0602

in n-nonane

26880 cm-1, f = 0.1113

27554 cm-1, f = 0.0883

exp. in n-nonane

25900 cm-1



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

We distinguished two isomers, A and B, which had different orientations of the hydroxyl group −OH with respect to the molecule’s core - see Table 2. As seen from this Table both isomers of compound 1, whose structures were optimized in the electronic ground state S0, have similar energy in this state and thus, both may exist at room temperature. Even more, less stable isomer B has higher dipole moment than the isomer A and thus it should be better stabilized in polar solvents, by the same decreasing the ground state energy difference between both isomers. Situation is different in the case of compound 2, where more stable isomer A should strongly predominate (its ground state energy is by 4685 cm-1 lower than the energy of conformer B). Low ground state energy of the isomer A of compound 2 is connected with formation of intermolecular hydrogen bond between the hydroxy and aldehyde groups. The calculated parameters of the hydrogen bond are: R(O,O) = 2.5826 Å, 72^1;10^2>

|10^1> 10^2>

6500 5500 4500 3500 2500 1500

500

|72^2>

|72^1>

-500 -1500 -2500 -3500 -4500 -5500 -6500

|10> 329 cm -1

-1

wavenumber [cm ]

Figure 5. Experimental absorption and fluorescence spectra of compound 2 in n-nonane at 5 K and the calculated Franck-Condon factors, presented in form of vertical lines. Right: two vibrations, active in the S1→S0 transition, which contribute mainly to the spectra.

Interesting observation, which was noticed during previous studies of 7hydroxycoumarin36,42, and also present for its "perylene-like" analog,27 was considerable increase of the bond length {1} (see structure inserted in Table 5) when the compounds were excited from S0 to S1 state. Changes of the lengths of two other C−O bonds, indicated as {2} and {3}, were not so big. The bond lengths of the studied coumarins, obtained by other authors and in the present work, are collected in Table 5. The bond lengthening which follows electronic excitation, by as much as 0.1 Å, is clearly visible for compound 1 (isomer A). However, creation of hydrogen bonding in the aldehyde relative 2 cancels the effect, and 14 ACS Paragon Plus Environment

Page 15 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


the length of the bond {1} is practically not altered in the both states (calculated values were 1.391 Å and 1.395 Å in the S0 and S1 states, respectively).

Table 5. Calculated lengths of selected bonds (given in Å) in the S0 and S1 states of 7hydroxycoumarin and some of its π-expanded relatives. Calculated transition energies of absorption (νabs) and fluorescence (νfl), and oscillator strengths of the S0 → S1 transition (f) are also given for comparison. calculation method compound

state

νabs = 35587 νfl = 34246

νabs = 24503 νfl = 21649 f = 0.248

νabs = 31453 νfl = 26882 f = 0123

S0 S1

{1} 1.358 1.402

{2} 1.185 1.191

{3} 1.344 1.336

S0 S1

1.383 1.489

1.207 1.216

1.354 1.354

S0 S1

1.383 2.300

1.203 1.172

S0 S1

1.394 1.425

1.210 1.213

1.361 1.358

(4)

S0 S1

1.382 1.483

1.211 1.217

1.365 1.347

(5)

1391

1.208

1.335

(5)

1.395

1.207

1.277

S0 νabs = 27948 isomer A νfl = 19362 S 1 f = 0.0364 isomer C (1) (2) (3) (4) (5)

HF and CIS/6-31+G(d), ref. [42]. PBE0 and TD PBE0/6-31+G(d), ref. [42]. MP2 and ADC(2)/aug-cc-pVTZ, ref [36]. B3LYP and TD B4LYP/6-31G(d,p), ref. [27]. B3LYP and TD B3LYP/6-31++G(d,p), [this work].

4. Conclusions 15 ACS Paragon Plus Environment

(1)

(2)

(3)


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The results of the present work indicate that the replacement of olefinic C-C double bond with benzene ring in a coumarin skeleton, lowers the energy of electronic transition (S0−S1) without an increase in the radiative rate, but with an increase in relaxation by the nonradiative channels. Considered in this work two derivatives of 3-hydroxybenzo[c]coumarin, named as compounds 1 and 2, have high dipole moment already in the electronic ground state S0. Their dipole moments even increase when molecules undergo transition to the excited S1 state. Such the situation should result in prominent solvent effect on their photophysical properties, especially in polar solvents. Unstructured shape of the absorption and fluorescence bands of compound 1 is associated with coexistence of two isomers, A and B, whose ground state energies differ by ∼150 cm-1, and furthermore, molecules of this compound occupy a number of different sites in the frozen n-hexane matrix (what was manifested by the wavelength dependence of the fluorescence decay time). Broad and Stokes shifted fluorescence spectrum of compound 2 has nature in the excited state intramolecular proton transfer mechanism. Ground state stable isomer A after being transferred to the S1 state (as the result of absorption of excitation light) relaxes without barrier to the S1 state of isomer C. Return (radiatively or non-radiatively) of isomer C to its S0 state is followed by structural relaxation to the S0 state of isomer A. Fast proton transfer to the S1 state of isomer C, and short lifetime of this state, does not allow for efficient intersystem crossing to a manifold of triplet states of isomer A, and phosphorescence emission (which we observed for compound 1) is lacking for compound 2. According to our calculations, in the considered compounds energies of the optimized nπ* states are located above the lowest energy excited ππ* states, and thus should not contribute to the nonradiative relaxation of the excitation energy. This conclusion is valid for compounds 1 and 2 as long as we use low energy excitations.

Acknowledgements The work was financially supported by the Polish National Science Centre, grants no. 2012/4/A/ST2/00100 and 2012/06/A/ST5/00216. Theoretical calculations were performed at the interdisciplinary Center of Mathematical and Computer Modeling (ICM) of the Warsaw University under the computational grant No. G-32-10. 16 ACS Paragon Plus Environment

Page 16 of 23

Page 17 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Supporting Information. Fluorescence decays of both studied compounds in n-nonane at 5 K, calculated electronic transition energies for structures optimized in the ground and excited states, phosphorescence decay and electronic charge distribution of compound 1. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION Corresponding Authors [email protected], [email protected]

References (1) Kennedy, R. O.; Thornes, R. D. Coumarins: Biology, Applications and Mode of Action. Wiley and Sons: Chichester, 1997. (2) Liu, X.; Cole, J. M.; Waddell, P. G.; Lin, T.-C.; Radia, J.; Zeidler, A. Molecular Origins of Optoelectronic Properties in Coumarin Dyes: Toward Designer Solar Cell and Laser Applications. J. Phys. Chem. A 2012, 116, 727−737. (3) Mishra, A.; Fischer, M. K. R.; Bäuerle, P. Metal-Free Organic Dyes for Dye-Sensitized Solar Cells: From Structure: Property Relationships to Design Rules. Angew. Chem., Int. Ed. 2009, 48, 2474−2499. (4) Narayanaswamy, N.; Kumar, M.; Das, S.; Sharma, R.; Samanta, P. K.; Pati, S. K.; Dhar, S. K.; Kundu, T. K.; Govindaraju, T. A Thiazole Coumarin (TC) Turn-On Fluorescence Probe for AT-Base Pair Detection and Multipurpose Applications in Different Biological Systems. Scientific Reports 2014, 4, 6476-6485. (5) Messaoudi, S.; Brion, J.-D.; Alami, M. Palladium-Catalyzed Decarboxylative Coupling of Quinolinone-3-Carboxylic Acids and Related Heterocyclic Carboxylic Acids with (Hetero)aryl Halides. Org. Lett. 2012, 14, 1496−1499. (6) Min, M.; Hong, S. Regioselective Palladium-catalyzed Direct Cross-coupling of Coumarins with Simple Arenes. Chem. Commun. 2012, 48, 9613−9615. (7) Tsukamoto, K.; Shinohara, Y.; Iwasaki, S.; Maeda, H. A Coumarin-based Fluorescent Probe for Hg2+ and Ag+ with an N0-acetylthioureido Group as a Fluorescence Switch. Chem. Commun. 2011, 47, 5073−5075. 17 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(8) Reddie, K. G.; Humphries, W. H.; Bain, C. P.; Payne, C. K.; Kemp, M. L.; Murthy, N. Fluorescent Coumarin Thiols Measure Biological Redox Couples. Org. Lett. 2012, 14, 680−683. (9) Siegrist, C. A. E.; Hefti, H.; Mayer, H. R.; Schmidt, E. Fluorescent Whitening Agents 1973-1985 Rev. Prog. Coloration 1987, 17, 39-55. (10) Koefod, A. R. S.; Mann, K. R. Preparation, Photochemistry, and Electronic Structures of Coumarin Laser Dye Complexes of Cyclopentadienylruthenium(II). Inorg. Chem. 1989, 28, 2285–2290. (11) Tasch, B. S.; Brandstatter, C.; Meghdadi, F.; Leising, G.; Froyer, G.; Athouel, L. RedGreen-Blue Light Emission from a Thin Film Electroluminescence Device Based on Parahexaphenyl. Adv. Mater. 1997, 9, 33–36. (12) Adronov, A.; Gilat, S. L.; Fréchet, J. M. J.; Ohta, K.; Neuwahl, F. V. R.; Fleming, G. R. Light Harvesting and Energy Transfer in Laser−Dye-Labeled Poly(aryl ether) Dendrimers. J. Am. Chem. Soc. 2000, 122, 1175−1185. (13) Tasior, M.; Gryko, D. T.; Pielacińska, D.; Zanelli, A.; Flamigni, L. Trans-A2B-corroles Bearing a Coumarin Moiety - From Synthesis to Photophysics. Chem. Asian J. 2010, 5, 130– 140. (14) Nazir, R.; Danilevicius, P.; Ciuciu, A. I.; Chatzinikolaidou, M.; Gray, D.; Flamigni, L.; Farsari, M.; Gryko, D. T. π-Expanded Ketocoumarins as Efficient, Biocompatible Initiators for Two-Photon-Induced Polymerization. Chem. Mat. 2014, 26, 3175-3184. (15) Min, M.; Kim, B.; Hong, S. Direct C–H Cross-coupling Approach to Heteroaryl Coumarins. Org. Biomol. Chem. 2012, 10, 2692–2698. (16) Wolfbeis, O. S. Synthese und Eigenschaften Einiger Neuer Hydroxylsubstituierter Laserfarbstoffe auf Cumarinbasis Lumineszierende Heterocyclen, 8. Mitt. Monatsh. Chem. 1978, 109, 1413–1421. (17) Koch, R.; Berstermann, H. M.; Wentrup, C. Formation of Allenyl Ketones, 3Ethynylcoumarins, and Arylfurans, Furylfurans, and Furylthiophenes by Flash Vacuum Thermolysis of 3-Methylidenefuran-2(3H)-ones. J. Org. Chem. 2014, 79, 65−71. (18) Shao, Z.; Xu, L.; Wang, L.; Wei, H.; ad Xiao, J. Catalyst-free Tandem Michael Addition/decarboxylation of (Thio)coumarin-3-carboxylic Acids with Indoles: Facile Synthesis of Indole-3-substituted 3,4-dihydro(thio)coumarins. Org. Biomol. Chem. 2014, 12, 2185-2188.


Page 18 of 23

Page 19 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(19) Pottie, I. R.; Nandaluru, P. R.; Benoit, W. L.; Miller, D. O.; Dawe L. N.; Bodwell, G. J. Synthesis of 6H-Dibenzo[b,d]pyran-6-ones Using the Inverse Electron Demand Diels– Alder Reaction. J. Org. Chem. 2011, 76, 9015-9030. (20) Kim, Y.; Moon, Y.; Kang, D.; Hong, S. Synthesis of Heterocyclic-fused Benzopyrans via the Pd(II)-catalyzed C–H alkenylation/C–O Cyclization of Flavones and Coumarins. Org. Biomol. Chem. 2014, 12, 3413-3422. (21) Von Pechmann, H.; Welsh, W. Ueber Einige Neue Cumarine. Ber. Dtsch. Chem. Ges. 1884, 17, 1646-1652. (22) Högberg, T.; Vora, M.; Drake, S. D.; Mitscher, L. A.; Chu, D. T. W. Structure-Activity Relationships among DNA-Gyrase Inhibitors. Synthesis and Antimicrobial Evaluation of Chromones and Coumarinss Related to Oxolinic Acid. Acta Chem. Scand. Ser. B 1984, 38, 359–366. (23) Poronik, Y. M.; Shandura, M. P.; Kovtun, Y. P. Synthesis of 6H,7H-[1]benzopyrano[3,4-c][1]benzopyran-6,7-diones. Chem. Heterocycl. Compd. 2006, 42, 410–411. (24) Tasior, M.; Poronik, Y.; Vakuliuk, O.; Sadowski, B.; Karczewski M.; Gryko, D. T. V-Shaped Bis-Coumarins: Synthesis and Optical Properties. J. Org. Chem. 2014, 79, 87238732. (25) Węcławski, M. K.; Tasior, M.; Hammann, T.; Cywiński, P. J.; Gryko, D. T. From πexpanded Coumarins to π-expanded Pentacenes. Chem. Commun. 2014, 50, 9105–9108. (26) Nandaluru P. L.; Bodwell, G. J. Multicomponent Synthesis of 6H-Dibenzo[b,d]pyran-6ones and a Total Synthesis of Cannabinol. Org. Lett. 2012, 14, 310-313. (27) Tasior, M.; Deperasińska, I.; Morawska, K.; Banasiewicz, M.; Vakuliuk, O.; Kozankiewicz B.; Gryko, D. T. Vertically π-expanded Coumarin – Synthesis via the Scholl Reaction and Photophysical Properties. Phys. Chem. Chem. Phys. 2014, 16, 18268-18275. (28) Tasior, M.; Kim, D.; Singha, S.; Krzeszewski, M.; Ahn, K. H.; Gryko, D. T. π-Expanded Coumarins: Synthesis, Optical Properties and Applications. J. Mater. Chem. C 2015, 3, 14211446. (29) Kim, I.; Xuan, Q. P.; Moon, H.; Jun, Y. W.; Ahn, K. H. Synthesis of Benzocoumarins and Characterization of Their Photophysical Properties. Asian J. Org. Chem. 2014, 3, 1089−1096. (30) Kim, D.; Singha, S.; Wang, T.; Seo, E.; Lee, J. H.; Lee, S.-J.; Kim, K. H.; Ahn, K. H. In Vivo Two-photonFluorescent Imaging of Fluoride with a Desilylation-based Reactive Probe. Chem. Commun. 2012, 48, 10243−10245. 19 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(31) Liu, X.; Xu, Z.; Cole, J. M. Molecular Design of UV−vis Absorption and Emission Properties in Organic Fluorophores: Toward Larger Bathochromic Shifts, Enhanced Molar Extinction Coefficients, and Greater Stokes Shifts. J. Phys. Chem. C 2013, 117, 16584−16595. (32) Krzeszewski, M.; Vakuliuk, O.; Gryko, D. T. Color-Tunable Fluorescent Dyes Based on Benzo[c]coumarin. Eur. J. Org. Chem. 2013, 5631-5644 . (33) Skonieczny, K.; Charalambidis, G.; Tasior, M.; Krzeszewski, M.; Kalkan-Burat, A.; Coutsolelos, A. G.; Gryko, D. T. General and Efficient Protocol for Formylation of Aromatic and Heterocyclic Phenols. Synthesis 2012, 44, 3683-3687. (34) Fink, D. W.; Koehler, W. R. pH Effects on Fluorescence of Umbelliferone. Anal. Chem. 1970, 42, 990-993. (35) Nizomov, N.; Kholov, A. U.; Ishchenko, A. A.; Ishchenko, V. V.; Khilya, V. P. Electronic Structure and Spectral Fluorescence Properties of Umbelliferone and Herniarin, J. Appl. Spectr. 2007, 74, 626-634. (36) Krauter, C. M.; Mӧhring, J.; Buckup, T.; Pernpointner, M.; Motzkus, M. Ultrafast Branching in the Excited State of Coumarin and Umbelliferone. Phys. Chem. Chem. Phys. 2013, 15, 17846-17861. (37) Gök, E. Investigation of Binding Properties of Umbelliferone (7-Hydroxycoumarin) to Lysozyme. J. Fluoresc. 2013, 23, 333–338. (38)

Sebastian, S.; Sylvestre, S.; Jayarajan, D.; Amalanathan, M.; Oudayakumar, K.;

Gnanapoongothai, T.; Jayavarthanan, T. Molecular structure, Normal Coordinate Analysis, Harmonic Vibrational Frequencies, Natural Bond Orbital, TD-DFT Calculations and Biological Activity Analysis of Antioxidant Drug 7-hydroxycoumarin. Spectrochim. Acta, Part A 2013, 101, 370–381. (39) Brett, T. J.; Alexander, J. M.; Stezowski, J. J. Chemical Insight from Crystallographic Disorder - Structural Studies of Supramolecular Photochemical Systems. Part 2. The bcyclodextrin/ 4,7-dimethylcoumarin Inclusion Complex: A New b-cyclodextrin Dimer Packing Type, Unanticipated Photoproduct Formation, and an Examination of Guest Influence on b-CD Dimer Packing. J. Chem. Soc., Perkin Trans. 2 2000, 2, 1095–1103. (40) Heldt, J. R.; Heldt, J.; Stoń, M.; Diehl, H. A. Photophysical Properties of 4-alkyl- and 7alkoxycoumarin Derivatives. Absorption and Emission Spectra, Fluorescence Quantum Yield and Decay Time. Spectrochimica Acta Part A 1995, 51, 1549-1563. (41) Jacquemin, D.; Perpète, E.A.; Scalmani, G.; Frisch, M. J.; Assfeld, X.; Ciofini, I.; Adamo, C. Time-dependent Density Functional Theory Investigation of the Absorption, 20 ACS Paragon Plus Environment

Page 20 of 23

Page 21 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Fluorescence, and Phosphorescence Spectra of Solvated Coumarins. J. Chem. Phys. 2006, 125, 164324. (42) Jacquemin, D.; Perpète, E.A.; Assfeld, X.; Scalmani, G.; Frisch, M. J.; Adamo, C. The Geometries, Absorption and Fluorescence Wavelengths of Solvated Fluorescent Coumarins: A CIS and TD-DFT Comparative Study. Chem. Phys. Lett. 2007, 438, 208–212. (43) Cerón-Carrasco, J. P.; Fanuel, M.; Charaf-Eddin, A.; Jacquemin, D. Interplay Between Solvent Models and Predicted Optical Spectra: A TD-DFT Study of 7-OH-coumarin. Chem. Phys. Lett. 2013, 556, 122–126. (44) S. Kumar, V.C. Rao, R.C. Rastogi, Excited-state Dipole Moments of Some Hydroxycoumarin Dyes Using an Efficient Solvatochromic Method Based on the Solvent Polarity Parameter, ETN. Spectrochimica Acta Part A 2001, 57, 41–47. (45) de Melo, J. S.; Fernandes, P. F. Spectroscopy and Photophysics of 4- and 7hydroxycoumarins and their Thione Analogs. J. Mol. Structure 2001, 565/566, 69-78. (46) Graber, D. R.; Grimes, M. W.; Haug, A. Electron Paramagnetic Resonance Studies of the Triplet State of Coumarin and Related Compounds. J. Chem. Phys. 1969, 50, 1623-1626. (47) Georgieva, I.; Trendafilova, N.; Aquino, A.; Lischka, H. Excited State Properties of 7Hydroxy-4-methylcoumarin in the Gas Phase and in Solution. A Theoretical Study. J. Phys. Chem. A 2005, 109, 11860-11869. (48) Lee, K. -S.; Kim, H. -J.; Kim, G. -H.; Shin, I.; Hong, J.-I. Fluorescent Chemodosimeter for Selective Detection of Cyanide in Water. Org. Lett. 2008, 10, 49-51. (49) Li, G. -Y.; Zhao, G. -J.; Han, K. -L.; He, G.-Z. A TD-DFT Study on the Cyanidechemosensing Mechanism of 8-formyl-7-hydroxycoumarin J. Comput. Chem. 2011, 32, 668– 674. (50) Lim, E. C. Proximity Effect in Molecular Photophysics: Dynamical Consequences of Pseudo-Jahn-Teller Interaction. J. Phys. Chem. 1986, 90, 6770–6777. (51) Frisch, M.J.; Trucks, G.W.; Schlegel, H.B.; Scuseria, G.E.; Robb, M.A.; Cheeseman, J.R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G.A.; et al. Gaussian 09, Revision B.01, Gaussian Inc., Wallingford CT, 2010. (52) Kozankiewicz, B. Electronic Energy Transfer in the Charge-transfer Crystal of 2,3Dimethylnaphthalene-Tetracyanobenzene. J. Lumin. 1997, 71, 37-46. (53) Barone, V.; Bloino, J.; Biczysko, M.; Santoro, F. Fully Integrated Approach to Compute Vibrationally Resolved Optical Spectra: From Small Molecules to Macrosystems. J. Chem. Theor. Comput. 2009, 5, 540–554.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(54) Bloino, J.; Biczysko, M.; Santoro, F.; Barone, V. General Approach to Compute Vibrationally Resolved One-Photon Electronic Spectra. J. Chem. Theor. Comput. 2010, 6, 1256–1274. (55) Sobolewski, A. L.; Domcke, W. Ab Initio Potential-Energy Functions for Excited State Intramolecular Proton Transfer: a Comparative Study of o-Hydroxybenzaldehyde, Salicylic Acid and 7-hydroxy-1-indanone. Phys. Chem. Chem. Phys. 1999, 1, 3065-3072. (56) Stock, K.; Bizjak, T.; Lochbrunner, S. Proton Transfer and Internal Conversion of oHydroxybenzaldehyde: Coherent versus Statistical Excited-State Ddynamics. Chem. Phys. Lett. 2002, 354, 409-416. (57) Douhal, A.; Lahmani, F.; Zewail, A. H. Proton-Transfer Reaction Dynamics. Chem. Physics 1996, 207, 477-498. (58) Jang, S.; Jin, S. I.; Park, C. R. TDDFT Potential Energy Functions for Excited State Intramolecular Proton Transfer of Salicylic Acid, 3-Aminosalicylic Acid, 5-Aminosalicylic Acid, and 5-Methoxysalicylic Acid. Bull. Kor. Chem. Soc. 2007, 28, 2343-2353. (59) Klessinger, M.; Michl, J. Excited States and Photochemistry of Organic Molecules, VCH Publisher Inc.: New York 1995, p. 246. (60) Felker, P. M.; Lambert, Wm. R.; Zewail, A. H. Picosecond Excitation of Jet-Cooled Hydrogen-Bonded Systems: Dispersed Fluorescence and Time-Resolved Studies of Methyl salicylate. J. Chem. Phys. 1982, 77, 1603-1605.


Page 22 of 23

Page 23 of 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Graphics:


coumarin - ACS Publications - American Chemical Society

Recommend Documents