Synthesis, crystal structure and two-photon excited fluorescence properties of three aurone derivatives

Article abstract of DOI:10.1016/j.saa.2012.11.018

Three aurone derivatives, Z-2-[(4-N,N-dimethylaminophenyl)methylene] benzofuran-3-one (1), Z-2-[(N-ethylcarbazol-3-yl)methylene]benzofuran-3-one (2) and Z-2-[(pyren-1-yl)methylene]benzofuran-3-one (3) have been synthesized by the cyclization of 2′-hydroxy

Full text of DOI:10.1016/j.saa.2012.11.018

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 103 (2013) 120–124
Contents lists available at SciVerse ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, crystal structure and two-photon excited fluorescence properties
of three aurone derivatives
a
a
a,b,
⇑
, Huihui Chen , Zhiqiang Liu , Qi Fang b
⇑
a
b,
Lin Ma , Yunhui Sun , Duxia Cao
a
School of Material Science and Engineering, Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022,
Shandong, China
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
b
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
"
Three aurone derivatives were
synthesized.
"
The compounds exhibit strong
yellow–green two-photon excited
fluorescence.
"
The compounds exhibit large two-
photon absorption cross-section.
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 August 2012
Received in revised form 29 October 2012
Accepted 5 November 2012
Available online 16 November 2012
Three aurone derivatives, Z-2-[(4-N,N-dimethylaminophenyl)methylene] benzofuran-3-one (1), Z-2-[(N-
ethylcarbazol-3-yl)methylene]benzofuran-3-one (2) and Z-2-[(pyren-1-yl)methylene]benzofuran-3-one
0
(
3) have been synthesized by the cyclization of 2 -hydroxychalcones. Their crystal structure, single-
and two-photon related absorption and fluorescence properties have been examined. Pumped by
60 nm laser pulses in femtosecond regime, the compounds exhibit strong yellow–green two-photon
excited fluorescence at 539 nm (1), 505 nm (2) and 524 nm (3) in THF with two-photon absorption
TPA) cross-section being 1536GM (1), 608GM (2) and 236GM (3).
Ó 2012 Elsevier B.V. All rights reserved.
8
Keywords:
(
Aurone derivatives
Two-photon absorption
Two-photon excited fluorescence
Crystal structure
Introduction
tional materials, which have been applied in many biologic fields
such as used as pigment and phytoalexins [1], alleviating allergic
manifestation [2] and also they found to exhibit antiviral [3], anti-
parasitic [4], antifungal [5], anticancer [6,7], antifeedant [8] activ-
ities, AChE [9] and tyrosinase inhibitory [10] and so on.
Nakayama group reported some aurone derivatives as single pho-
ton emission computed tomography probes for imaging b-amyloid
plaques in vivo [11,12]. To our best knowledge, up to now, there
are few reports about the nonlinear optical properties of aurones.
The backbone of aurone molecule has excellent planarity and from
the viewpoint of molecular engineering, molecular planarity plays
an important role in tuning nonlinear optical properties of
Aurones, [2-benzylidenebenzofuran-3(2H)-ones], the naturally
occurring yellow pigments of the plants that are structurally iso-
mers of flavones and can be obtained by oxidative cyclization of
0
2
-hydroxychalcones [1]. Aurones are a type of important func-
⇑
Corresponding authors. Address: School of Material Science and Engineering,
Shandong Provincial Key Laboratory of Preparation and Measurement of Building
Materials, University of Jinan, Jinan 250022, Shandong, China. Tel./fax: +86 531
8
973 6751.
E-mail addresses: duxiacao@ujn.edu.cn (D. Cao), zqliu@sdu.edu.cn (Z. Liu).
1
386-1425/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.saa.2012.11.018

L. Ma et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 103 (2013) 120–124
121
materials [13,14]. Then it is possible that this type of molecules
(d, J = 7.6 Hz, 1H), 8.64 (s, 1H). 13C NMR (CDCl
3
, 100 MHz): 13.98,
exhibit good nonlinear optical properties upon appropriate design.
Here, three aurone derivatives with dimethylamine, carbazolyl and
pyrene as terminal group were synthesized and their crystal struc-
tures, single-photon as well as two-photon related absorption and
fluorescence properties were investigated.
37.88, 109.03, 113.04, 115.53, 119.89, 120.86, 122.31, 123.05,
123.25, 123.33, 123.75, 124.60, 124.73, 126.46, 129.89, 136.37,
140.56, 140.96, 145.79, 165.82, 184.50.
Z-2-[(pyren-1-yl)methylene]benzofuran-3-one (3). Compound
3 was synthesized similarly to compound 1 to give orange powder
1
(
85%). H NMR (CDCl
3
400 MHz): d 7.23 (t, J = 8.3 Hz, 1H), 7.37 (d,
J = 8.3 Hz, 1H), 7.65 (t, J = 7.1 Hz, 1H), 7.86 (d, J = 7.6 Hz, 1H), 7.95
s, 1H), 7.99 (d, J = 7.6 Hz, 1H), 8.04 (d, J = 9.8 Hz, 1H), 8.10 (d,
J = 8.9 Hz, 1H), 8.17–8.22 (m, 4H), 8.55 (d, J = 9.3 Hz, 1H), 8.92 (d,
Experimental section
(
Synthesis and characterization
1
3
J = 8.2 Hz, 1H).
122.10, 122.93, 123.70, 124.77, 124.97, 125.14, 125.30, 125.88,
26.20, 126.33, 126.49, 127.58, 129.01, 129.08, 129.15, 130.89,
131.24, 131.47, 132.69, 136.93, 147.79, 166.39, 184.76. MS for
3
C NMR (CDCl , 100 MHz): 109.37, 113.21,
0
Three aurone derivatives 1–3 were synthesized from 2 -
hydroxychalcone according to Ref. [1]. The synthetic routes are
shown in Scheme 1. Chalcone derivatives 1 –3 were synthesized
according to Ref. [15]. Compounds 1 [1] and 2 [16] have been re-
ported previously, while 3 is a new aurone derivative. Mercuric
1
0
0
+
(
M + H) , Calcd exact mass: 347.1072, found 347.1079. Anal. Calcd
for C25 : C, 86.69; H, 4.07. Found C, 86.58; H, 4.09.
14 2
H O
2
acetate (Hg(OAc) ) and pyridine were purchased from Aladdin Re-
Photophysical properties measurement
agents. NMR spectra of the compounds were recorded on a Bruker
Avance III 400 MHz spectrometer at ambient temperature. High-
resolution mass spectra were recorded on an Agilent Q-TOF6510
spectrometer. Elemental analyses were carried out on a PE 2400
autoanalyzer.
UV–vis absorption and single-photon excited fluorescence
(
SPEF) spectra of the compounds in THF were recorded at room
temperature on a Shimadzu UV2550 spectrophotometer and an
Edinburgh FLS 920 spectrometer, respectively. The SPEF quantum
Synthesis
of
Z-2-[(4-N,N-dimethylaminophenyl)methy-
0
yields
U were measured by using a standard method [17] with
lene]benzofuran-3-one (1) [1]. 0.10 g (0.38 mmol) Compound 1
and 0.12 g (0.38 mmol) mercuric acetate were dissolved in 20 mL
pyridine. The resulting mixture was heated with stirring at reflux
for 3 h. After the mixture had cooled to room temperature, it was
poured into ice water (50 mL) and acidified with dil. HCl. The pre-
cipitated solid was filtered, washed twice with cold water and
dried in vacuum. The separated precipitate was repeatedly re-crys-
coumarin 307 [18] as the standard. Two-photon excited fluores-
ꢁ3
ꢁ1
cence spectra of the compounds in THF with C = 1.0 ꢀ 10 mol L
were performed with a femtosecond Ti:sapphire laser (80 MHz,
0 fs pulse width, Spectra- Physics Inc., Tsunami 3941-M1 BB) over
8
the range 730–880 nm as pump source. The input laser powder
was 150 mW for all measurements.
tallized from dichloromethane–ethanol to give red plates (0.083 g,
1
yield 82%). H NMR (CDCl
3
, 400 MHz): d 3.10 (s, 6H), 6.82 (d,
Structure determination
J = 8.7 Hz, 2H), 6.94 (s, 1H), 7.21 (t, J = 7.6 Hz, 1H), 7.34 (d,
J = 8.3 Hz, 1H), 7.63 (t, J = 8.0 Hz, 1H), 7.83 (d, J = 7.0 Hz, 1H), 7.88
0
0
Crystal structures of 1 and 2 have been reported by our group
0
(
d, J = 8.9 Hz, 2H).
[19,20]. Here, a set of new crystal structure data of compound 1
has been obtained. Single crystals of compounds 1 , 1 and 2 were
0
Z-2-[(N-ethylcarbazol-3-yl)methylene]benzofuran-3-one
(2).
Compound 2 was synthesized similarly to compound 1 to give yel-
obtained by slow evaporation of the solutions of the compounds
in dichloromethane–ethanol. X-ray diffraction data of the com-
pounds were collected on a Bruker Smart APEX-II CCD X-ray single
1
low needles (82%). H NMR (CDCl
H), 4.36 (q, J = 7.2 Hz, 2H), 7.14 (s, 1H), 7.21 (t, J = 7.4 Hz, 1H), 7.31
t, J = 7.4 Hz, 1H), 7.38–7.44 (m, 3H), 7.51 (t, J = 7.2 Hz, 1H), 7.65 (t,
J = 7.8 Hz, 1H), 7.83 (d, J = 7.2 Hz, 1H), 8.05 (d, J = 8.8 Hz, 1H), 8.18
3
, 400 MHz): d 1.46 (t, J = 7.2 Hz,
3
(
crystal diffractometer with a graphite-monochromated Mo K
a
radiation (k = 0.71069 Å) at 296(2)K. The CIF files of compounds 1
Scheme 1. Synthetic routes to compounds 1–3.

1
22
L. Ma et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 103 (2013) 120–124
and 2 have been deposited with the Cambridge structure database
and assigned the following numbers: CCDC 895294 and 895295.
Crystal data, data collections and structure refinements of com-
Table 1
Selected geometric parameters (Å, °) of the crystal structures.
0
0
1
1
2
2
0
pounds 1 , 1 and 2 are shown in Table S1.
C1–O2 (Å)
C1–C6 (Å)
C6–C7 (Å)
C7–C8 (Å)
C8–C9 (Å)
C9–C10 (Å)
C7–O1 (Å)
Dihedral angle
1.3452(16)
1.4105(18)
1.4758(18)
1.4545(18)
1.344(2)
1.4413(18)
1.2514(15)
10.30(7)
1.382(3)
1.376(4)
1.457(4)
1.467(4)
1.334(4)
1.445(4)
1.235(3)
5.80(13)
1.347(3)
1.397(3)
1.471(3)
1.457(3)
1.328(3)
1.454(3)
1.250(3)
1.3805(17)
1.383(2)
1.459(2)
1.4781(18)
1.332(2)
1.4476(17)
1.2240(16)
5.77(6)
Results and discussion
Synthesis and crystal structure
a
a
(°)
11.58(12)
All the aurone compounds were synthesized by the cyclization
of chalcone using mercury(II) acetate in pyridine with good yield.
The products obtained were Z-isomers, which was proved by crys-
tal structure.
a
0
The dihedral angles between two benzene groups (1 and 1) or between car-
0
bazole and benzene groups (2 and 2).
0
The molecular structures of compound 1 , 1 and 2 are shown in
0
Fig. 1 (2) and Fig. S1 (1 and 1). Selected geometric parameters of
the crystal structures are shown in Table 1. Compound 1 is the
0
0
cyclization product of 1 . Compared to 1 , 1 exhibits better planar-
ity. The dihedral angle between two benzene groups are 5.80(13)°
(
Table 2
Photophysical properties of compounds 1–3 in THF.
0
0
1) and 10.30(7)° (1 ), respectively. From 2 to 2, similar phenome-
non was observed. The dihedral angle between the planes of the
carbazole and benzene groups are 5.77(6)° (2) and 11.58(12)° (2 )
20], respectively. From 1 to 1 and from 2 to 2, some band lengths
change because of the cyclization reaction. C1–C6 and C6–C7 are
shortened because of the formation of furan ring. Especially, C1–
C6 is shortened smartly from 1.4105 (18) Å (1 ) to 1.376 (4) Å (1).
kabs
kSPEF
kTPEF
Compounds
e
(10
U
r
e
r
4
ꢁ1
ꢁ1
(nm)
M
cm
)
(nm)
(nm)
GM GM
0
1
2
3
451
428
451
3.86
4.16
2.67
535
490
509
0.11 539
0.12 505
0.14 524
169 1536
0
0
[
73
33
608
236
0
Linear absorption and single-photon excited fluorescence properties
Linear absorption and single-photon excited fluorescence
(
SPEF) properties of the compounds in THF are shown in Table 2
and the spectra are shown in Fig. 2.
All the compounds exhibit linear absorption in blue wavelength
region at 451 nm (1), 428 nm (2) and 451 nm (3). Compounds 1
and 2 exhibit much stronger linear absorption than compound 3,
which indicates that the stronger electron donating ability of ter-
minate group is beneficial to charge transfer and linear absorption.
1
and 3 possess similar absorption peak and have a 23 nm red shift
relative to 2. Compounds 1 and 3 show strong yellow–green SPEF
fluorescence at 535 nm and 509 nm, respectively, but compound
2
exhibits strong blue fluorescence at 490 nm. The red shift of
absorption and fluorescence peak of 1 relative to that of 2 may
be is derived from the stronger electron donating ability of dimeth-
ylamine group than carbazolyl group, which make the molecule
polarity increase and energy gaps decrease. Although pyrene group
in 3 possesses weaker electron donating ability than carbazolyl
group, the absorption and fluorescence peaks are also red-shifted
relative to that of 2, which maybe is because pyrene group pos-
sesses perfect conjugation and rigidity and then make the electron
delocalization increase. Compound 3 possesses the highest fluores-
cence quantum yield and the strongest SPEF fluorescence emission,
Fig. 2. Linear absorption and SPEF spectra of compounds 1–3 in THF.
which also maybe derived from the perfect conjugation and rigid-
ity of pyrene group.
In order to furtherly investigate the relation between the
molecular structure and fluorescence properties. The SPEF fluores-
0
cence properties of three compounds 4 -N, N-dimethylamine chal-
0
0
cone (0), 2-hydroxyl-4 -N, N-dimethylamine chalcone (1 ) and 1
are investigated and the spectra are shown in Fig. 3.
0
From Fig. 3, one can see that compound 1 and 0 have almost
same peak position in their emission spectra, but the fluorescent
intensity of 0 is nearly 100 times higher than that of compound
0
0
1
. The weak fluorescence emission of 1 is maybe due to the ultra-
fast intramolecular hydrogen atom transfer and/or ultrafast deacti-
vation processes such as intersystem crossing and internal
conversion through the hydrogen bonding [21,22]. Aurone com-
pound 1 possesses the strongest fluorescence emission and the
fluorescence peak has ꢂ30 nm red shift relative the other com-
pounds, which maybe is derived from its stronger rigidity and pla-
narity and the disappear of hydroxyl group during the cyclization
reaction.
Fig. 1. The molecular structure of compound 2.

L. Ma et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 103 (2013) 120–124
123
0
Fig. 3. Fluorescence spectra of compounds 0, 1 and 1 in THF.
Fig. 5. Two-photon excited fluorescence spectra of compounds 1–3 in THF with
C = 1.0 ꢀ 10ꢁ mol L
3
ꢁ1
.
TPEF spectrum of compound 1 is similar to its SPEF spectrum
with an only 4 nm red shift. But TPEF spectra of both compounds
Two-photon excited fluorescence properties
2
and 3 have 15 nm red shift relative to their SPEF. The red shifts
Two-photon excited fluorescence (TPEF) was collected at a
direction perpendicular to the pump beam. From linear absorption
spectra (Fig. 2), one can see that the compounds are linear optical
penetrable in the range from 550 to 1000 nm. Therefore, any emis-
sion induced by excitation at this wavelength range should be de-
rived from multiphoton absorption process. As shown in Fig. 4,
TPEF intensity of compound 3 is almost proportional to the square
of the input laser power from 80 mW to 200 mW, which suggests
the two-photon excitation mechanism.
Two-photon excitation spectra (TPE) of the compounds 1–3 in
THF were obtained with the excitation wavelength from 730 nm
to 880 nm. From Fig. 4, one can see the optimal excitation wave-
lengths are 860 nm for all the compounds, which are smaller than
twice of their linear absorption.
are derived from the re-absorption of the fluorescence within the
concentrated solution. The smaller red shift of compound 1 is de-
rived from its large Stokes Shifts and lower re-absorption.
TPA and TPEF cross-sections of the compounds (
e
r and r ,
respectively) were obtained using two-photon excited fluores-
cence method with coumarin 307 as reference [23]. As shown in
Table 2, TPA cross-section of the compounds are 1536GM (1),
6
08GM (2) and 236GM (3). The TPA cross-section values are com-
parable to the values reported by Refs. [24–27] and these com-
pounds show promising applications in nonlinear optical area.
Conclusion
The compounds exhibit strong yellow–green two-photon ex-
cited fluorescence (Fig. 5) at 539 nm (1), 505 nm (2) and 524 nm
Three aurone derivatives are synthesized and their linear
absorption, single-photon and two-photon excited fluorescence
properties in THF are investigated. The compounds exhibit strong
yellow–green two-photon excited fluorescence emission and com-
pound 1 with dimethylamine as terminate donor group possesses
the largest TPA cross-section 1536GM.
(3). Compound 1 exhibits the strongest TPEF emission compared
to other two compounds and the fluorescence intensity is about
2
.6 and 6.3 times that of 2 and 3, respectively, although compound
3
possesses the strongest SPEF emission and the highest fluores-
cence quantum yield. This phenomenon indicates that both strong
SPEF intensity and charge transfer are beneficial to TPEF.
Acknowledgements
This work was supported by the National Natural Science Foun-
dation of China (20802026, 50803033), Natural Science Foundation
of Shandong Province (Q2008F02) and Science and Technology Star
Funds of Jinan (20110314).
Appendix A. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.saa.2012.11.018.
References
[
1] S. Venkateswarlu, G.K. Panchagnula, A.L. Gottumukkala, G.V. Subbaraju,
Tetrahedron 63 (2007) 6909–6914.
[
[
2] N.N. Agrawal, P.A. Soni, Indian J. Chem. 45B (2006) 1301–1303.
3] R. Haudecoeur, A. Ahmed-Belkacem, W. Yi, A. Fortuné, R. Brillet, C. Belle, E.
Nicolle, C. Pallier, J.M. Pawlotsky, A. Boumendjel, J. Med. Chem. 54 (2011)
5395–5402.
[
[
4] A. Boumendjel, Curr. Med. Chem. 10 (2003) 2621–2630.
5] B.P. Bandgar, S.A. Patil, B.L. Korbad, S.C. Biradar, S.N. Nile, C.N. Khobragade, Eur.
J. Med. Chem. 45 (2010) 3223–3227.
Fig. 4. Two-photon excitation spectra of compounds 1–3 in THF with
ꢁ
3
ꢁ1
C = 1.0 ꢀ 10 mol L . Inset: The output fluorescence intensity vs. the input power
[6] N.J. Lawrence, D. Rennison, A.T. McGown, J.A. Hadfield, Bioorg. Med. Chem.
Lett. 13 (2003) 3759–3763.
square for 1 in THF.

1
24
L. Ma et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 103 (2013) 120–124
[
7] W. Huang, M.Z. Liu, Y. Li, Y. Tan, G.F. Yang, Bioorg Med. Chem. 15 (2007) 5191–
197.
[15] Y.H. Sun, H.H. Chen, D.X. Cao, Z.Q. Liu, H.Y. Chen, Y.L. Deng, Q. Fang, J.
Photochem. Photobiol. A 244 (2012) 65–70.
5
[
[
8] M. Morimoto, H. Fukumoto, T. Nozoe, A. Hagiwara, K. Komai, J. Agric. Food
Chem. 55 (2007) 700–705.
9] R. Sheng, Y. Xu, C.Q. Hu, J. Zhang, X. Lin, J.Y. Li, B. Yang, Q.J. He, Y.Z. Hu, Eur. J.
Med. Chem. 44 (2009) 7–17.
[16] A. Shibuya, Eur. Pat. Appl. (2006). 49–49.
[17] J.N. Demas, G.A. Crosby, J. Phys. Chem. 75 (1971) 991–1024.
[18] G.A. Reynolds, K.H. Drexhage, Opt. Commun. 13 (1975) 222–225.
[19] Z.Q. Liu, Q. Fang, W.T. Yu, G. Xue, D.X. Cao, M.H. Jiang, Acta Cryst. C58 (2002)
o445–o446.
[20] D.X. Cao, G.Z. Li, G. Xue, W.T. Yu, Z.Q. Liu, Acta Cryst. E61 (2005) o977–o979.
[21] T. Teshima, M. Takeishi, T. Arai, New J. Chem. 33 (2009) 1393–1401.
[22] Y. Norikane, H. Itoh, T. Arai, J. Phys. Chem. A 106 (2002) 2766–2776.
[23] C. Xu, W.W. Webb, J. Opt. Soc. Am. B 13 (1996) 481–491.
[24] Z.Q. Liu, Q. Fang, D.X. Cao, D. Wang, G.B. Xu, Org. Lett. 6 (2004) 2933–2936.
[25] C.D. Andrade, C.O. Yanez, L. Rodriguez, K.D. Belfield, J. Org. Chem. 75 (2010)
3975–3982.
[
[
[
[
10] S. Okombi, D. Rival, S. Bonnet, A.M. Mariotte, E. Perrier, A. Boumendjel, J. Med.
Chem. 49 (2006) 329–333.
11] M. Ono, R. Ikeoka, H. Watanabe, H. Kimura, T. Fuchigami, M. Haratake, H. Saji,
M. Nakayama, Bioorg. Med. Chem. Lett. 20 (2010) 5743–5748.
12] Y. Maya, M. Ono, H. Watanabe, M. Haratake, Hideo Saji, M. Nakayama,
Bioconjugate Chem. 20 (2009) 95–101.
13] M. Albota, D. Beljonne, J.L. Brédas, J.E. Ehrlich, J.Y. Fu, A.A. Heikal, S.E. Hess, T.
Kogej, M.D. Levin, S.R. Marder, D. McCord-Maughon, J.W. Perry, H. Röckel, M.
Rumi, G. Subramaniam, W.W. Webb, X.-L. Wu, C. Xu, Science 281 (1998) 1653–
656.
14] D.X. Cao, Z.Q. Liu, G.H. Zhang, F.X. Cao, H.Y. Chen, G.Z. Li, Dyes Pigments 76
2008) 118–124.
[26] L. Echevarria, I. Moreno, J. Camacho, M.C. Salazar, A. Hernández, Spectrochim.
Acta Part A 97 (2012) 274–276.
[27] D.X. Cao, Z.Q. Liu, G.Z. Li, Sens. Actuators B 133 (2008) 489–492.
1
[
(