A highly fluorescent anthracene-containing hybrid material exhibiting tunable blue-green emission based on the formation of an unusual "T-shaped" excimer

Article abstract of DOI:10.1002/chem.200600514

A series of flexible bis(9-an-thryldiamine) ligands (L1-L3) linked with alkyl spacers of different chain length was synthesized and characterized, in order to investigate the coordination behavior of these diamine ligands with metal ions (Zn²⁺, etc.) based on fluorescence measurements. The results showed that, in the case of anthryldiamine ligands bearing two- or four-carbon links, the zinc ion induced a chelation-enhanced fluorescence (CHEF) effect in aqueous media, while a trace amount of water could selectively quench the blue emission of the Zn^II complex with a three-carbonlinked ligand (1). Meanwhile, the introduction of more water (concentration >11%) resulted in the formation of a new green luminescent species; the luminescence intensity was enhanced stepwise to a maximum with addition of approximately 30% water in THF solution. The peak position (centered at approximately 500 nm) and the lifetime measurement (τ = 19.59ns) indicated that the green luminescence was attributable to a novel edge-to-face dimeric conformation ("T-shaped" conformation) of anthracene, and not to the more common face-to-face dimeric conformation. Accordingly, ¹H NMR spectroscopic studies in nonaqueous or aqueous solution confirmed this T-shaped conformation, which is consistent with the results of single-crystal X-ray structure analysis and solid-state photoluminescence studies.

Full text of DOI:10.1002/chem.200600514

DOI: 10.1002/chem.200600514
A Highly Fluorescent Anthracene-Containing Hybrid Material Exhibiting
Tunable Blue–Green Emission Based on the Formation of an Unusual
“T-Shaped” Excimer
Guoqi Zhang,[a] Guoqiang Yang,*[a] Shuangqing Wang,[a] Qingqi Chen,[b] and
Jin Shi Ma*[a]
Abstract: A series of flexible bis(9-an-
thryldiamine) ligands (L1–L3) linked
with alkyl spacers of different chain
length was synthesized and character-
ized, in order to investigate the coordi-
nation behavior of these diamine li-
ZnII complex with
a
three-carbon-
time measurement (t=19.59 ns) indi-
cated that the green luminescence was
attributable to a novel edge-to-face di-
meric conformation (“T-shaped” con-
formation) of anthracene, and not to
the more common face-to-face dimeric
conformation. Accordingly, 1H NMR
spectroscopic studies in nonaqueous or
aqueous solution confirmed this T-
shaped conformation, which is consis-
tent with the results of single-crystal X-
ray structure analysis and solid-state
photoluminescence studies.
linked ligand (1). Meanwhile, the intro-
duction of more water (concentration
>11%) resulted in the formation of a
new green luminescent species; the lu-
minescence intensity was enhanced
stepwise to a maximum with addition
of approximately 30% water in THF
solution. The peak position (centered
at approximately 500 nm) and the life-
gands with metal ions (Zn2+
, etc.)
based on fluorescence measurements.
The results showed that, in the case of
anthryldiamine ligands bearing two- or
four-carbon links, the zinc ion induced
a
chelation-enhanced fluorescence
Keywords: anthracene · excimers ·
(CHEF) effect in aqueous media, while
a trace amount of water could selec-
tively quench the blue emission of the
fluorescence
chemistry
·
sensors
·
water
Introduction
tremendous number of anthracene-based organic materials
have been investigated with the aim of potential applica-
tions as photoluminescence (PL) and/or electroluminescence
(EL) devices in films and the solid state, the practical devel-
opment of PL and EL devices is in fact restricted, usually
owing to their poor stability. In contrast, strongly lumines-
cent anthracene-based inorganic–organic hybrid materials
with higher stability could be a class of promising candidates
for light-emitting as well as EL applications.[2]
Luminescent inorganic–organic hybrid compounds are an
important class of molecules that have extensive applica-
tions in biology, chemistry, and materials science. Anthra-
cene derivatives are key species in the design of luminescent
supramolecular materials, which have found wide utilization
in lasers, phosphors, and light-emitting devices.[1] Although a
On the other hand, anthrylpolyamine chemosensors have
been widely researched in pH switching, the detection of
alkali-metal, alkaline-earth, and heavy-metal cations, or
even the recognition of various anions.[2,3] In particular,
Czarnik and co-workers reported their pioneering work on
the investigation of anthrylpolyamine fluorescent chemosen-
sors for metal-ion recognition about two decades ago.[3a–c]
Originally, they reported the dramatic fluorescence enhance-
ment (up to 1000-fold) of 9,10-disubstituted anthrylpoly-
[a] Dr. G. Zhang, Prof. G. Yang, S. Wang, J. S. Ma
Beijing National Laboratory for Molecular Sciences
CAS Key Laboratory of Photochemistry
Institute of Chemistry, Chinese Academy of Sciences
Beijing 100080 (China)
Fax : (+86)10-8261-7315
E-mail: gqyang@iccas.ac.cn
jsma@iccas.ac.cn
[b] Dr. Q. Chen
Biomarin Pharmaceutical, Inc.
46 Galli Drive, Novato, CA 94949 (USA)
amine derivatives induced by zinc chloride in organic sol-
vent, and demonstrated a remarkable chelation-enhanced
fluorescence (CHEF) effect on these systems, indicating the
Supporting information for this article is available on the WWW
under http://www.chemeurj.org/ or from the author.
3630
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3630 – 3635

FULL PAPER
great potential of this type of organic compound as a techni-
cally facile fluorescent analytical probe.[3b]
ion remarkably results in the CHEF effect, similar to the ob-
served behavior of Czarnikꢁs anthrylpolyamine systems and
other reported polyamine donors.[3a,b,6] Indeed, both L1 and
L3 displayed strongly selective fluorescence enhancement
upon introduction of Zn2+ in hydrous media (see Support-
ing Information). But addition of Zn2+ to L2 resulted in no
obvious emission enhancement of anthracene monomer in
the presence of water, despite the increased emission in an-
hydrous organic solvent.
A strongly fluorescent complex 1 was obtained in high
yield by reacting L2 with zinc acetate in CH2Cl2/MeOH (1:1
v/v) at room temperature (Scheme 1). Complex 1 exhibits
the characteristic absorption of anthracene in the range of
320–380 nm, and shows strong blue luminescence both in
water-free solution and in the solid state on irradiation with
UV light. In common organic solvents, such as toluene, di-
chloromethane, THF, methanol, and ethanol, the quantum
efficiency of 1 is rather high (Ff =0.47 in THF, relative to
that of 9,10-diphenylanthracene,[7] and t=5.54 ns). However,
in solvents which contain a trace amount of water, the quan-
tum yield decreases dramatically. To elucidate the water-
In recent years, many luminescent inorganic–organic hy-
brids were found to efficiently detect neutral small mole-
cules, such as acetonitrile, ethanol, benzene, and toluene,[2]
which are of environmental importance. Despite the number
of reports on anthrylpolyamine systems as promising fluo-
rescent host compounds for guest recognition,[3,4] no water-
recognition anthrylpolyamine–metal hybrid was observed, as
almost all of them usually operate in hydrous media. Never-
theless, previous work has confirmed that water could to
some degree influence the complexation of metal ions to an
anthrylpolyamine host.[3b]
Herein, we present the first example of a highly fluores-
cent anthrylpolyamine–zinc(II) hybrid material which dis-
plays novel water-tunable blue–green light emission upon
UV irradiation both in solution and in the solid state. Inter-
estingly, we found that this complex was extremely sensitive
towards water in organic solution at a very low range of
concentration, but upon addition of a much larger amount
of water (over approximately 11%) a new green-light-emit-
ting species formed, which was clearly different from the be-
haviors of previously reported anthrylpolyamine derivatives.
Most excitingly, for the first time we observed directly the
formation of a “T-shaped” anthracene–anthracene dimer
both in solution and in the solid state, on the basis of de-
tailed spectroscopic, photophysical studies and X-ray struc-
ture analysis.
mediated fluorescence-quenching effect,
a fluorescence
spectrometric titration experiment was carried out sequen-
tially. Figure 1a shows clearly the expected quenching effect.
Upon increasing the water content from 1to 9 mL in a solu-
tion of 1 in dry THF (3 mL, concentration c=5 mm), the
emission gradually decreased, and the quantum efficiency
fell to 0.08 when 5 mL of water was added. This was proba-
bly because a small amount of water would interact partially
with zinc centers to release zinc ions from the amino group
of the ligands.[3b] Consequently, this resulted in the PET pro-
cess in the excited state and quenched the emission of the
anthracene monomer. This remarkable fluorescence quench-
ing property induced by a trace amount of water was very
interesting, and extremely rare examples exhibiting water-
recognition ability by fluorescence changes have been re-
ported.[8] Thus, compound 1 might have a potential applica-
tion as a fluorescent sensor for detecting trace amounts of
water.
Results and Discussion
The anthryldiamine ligands L1–L3 were efficiently synthe-
sized by condensation of 9-anthracylaldehyde and appropri-
ate diamines, followed by in situ reduction with excess
NaBH4 (Scheme 1). Ligands L1–L3 were found to be very
weakly emissive due to the well-known photoinduced elec-
tron transfer (PET) fluorescence quenching process.[5] To in-
vestigate the coordination properties of these diamine li-
gands with metal ions, we attempted to detect their fluores-
cent response to various metal ions. Accordingly, the zinc
It was further noted that when the water concentration in
THF was below 11%, the quenched emission of 1 was not
significantly changed. However,
when the water concentration
was higher than 11%, the emis-
sion changed dramatically and
a new emission band appeared
at approximately 500 nm (Fig-
ure 1b). The water-tuning emis-
sion of 1 was illustrated clearly
by the evolution of the fluores-
cence spectra with changing
water concentration, and the
corresponding photograph was
taken under
a
UV lamp
(Figure 2). It can be clearly
seen that the color of the emis-
sion in solution evolves from
Scheme 1.
Chem. Eur. J. 2007, 13, 3630 – 3635
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3631

G. Yang, J. S. Ma et al.
likely that molecules of 1 would tend to slightly aggregate in
the H2O/THF mixture when the water concentration was in-
creased, as most of the organic molecules did.[9] In order to
reveal the quantitative relationship between the new green
luminescence intensity and the water concentration in THF
solution, we plotted the changes in peak area of the green
luminescence around 500 nm with the increase of water con-
centration (see Supporting Information). The plot clearly
showed a sequential increase of the peak area of the green
luminescence with increasing water concentration in the
range of 11–30%, indicative of the quantitative formation of
a new emissive species. Compared to the most common an-
thracene-related compounds, which formed a face-to-face
dimeric conformation in solution and usually displayed an
emission band at 530–550 nm,[10] the emission band of 1 was
blue-shifted by approximately 30 nm. This finding suggested
that in solution, 1 did not adopt a face-to-face p-stacked di-
meric conformation but an edge-to-face dimeric conforma-
tion (T-shaped conformation), which was further indicated
by measurement of the lifetime of this species (t=19.59 ns),
remarkably different from the p-stacked dimer with a
longer lifetime (>200 ns).[11] Furthermore, this was also con-
1
firmed by the H NMR spectra in solution.
1H NMR spectroscopic studies are helpful for the investi-
gation of the aggregation interactions of 1 with the T-shaped
conformation in solution. Figure 3 displays the results of
Figure 1. a) Water-driven fluorescence quenching of 1 (c=5”10À6 m) in
THF (3 mL); water was added in amounts of 0, 1, 2, 3, 4, 5, 6, 7, 8, and
9 mL, respectively. Inset: Plot of emission intensity versus quantity of
added water in THF at 415 nm; lex =368 nm. b) Water-induced emission
changes of 1 (c=5 mm) in THF/H2O (from 9:1to 3:1v/v); lex =368 nm.
Inset: Fluorescence differential spectrum of 1 from those in THF and
H2O/THF (1:3 v/v).
Figure 3. Partial 1H NMR spectra of 1 in A) [D8]THF and B) [D8]THF/
D2O (70:30 v/v).
Figure 2. Photographs of fluorescence emission from the solution of 1 in
THF/H2O with changing water concentration (a–g: 0, 0.05, 0.1, 0.2, 5, 15,
and 30%, respectively) under a UV lamp. The concentration of the solu-
tions was kept at 5”10À6 m.
1H NMR spectral change in the low-field region before (A)
and after (B) water (D2O) was added to the [D8]THF solu-
tion. The most remarkable change came from the strong up-
field shift of one edge-ring proton (Hd) of the anthryl group,
which indicated that this proton was located in the shielding
area of the aromatic ring and was strongly shielded by the
“ring current” in hydrous solution. This result supports the
formation of a T-shaped anthracene–anthracene dimer in
the new aggregate structure upon addition of water.
blue to green with increasing water content. Such a blue–
green emission change could also be observed when the
THF or THF/H2O solutions of 1 were deposited on glass
surfaces as a thin film by the spin-coating method (see Sup-
porting Information). The dramatic spectral changes in-
duced by water could be attributed to the formation of ag-
gregates in solution. As 1 was insoluble in water, it was very
Single crystals of 1 were obtained by slow evaporation of
toluene/ether solution. Careful diffusion of ether to CH2Cl2,
3632
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3630 – 3635

Fluorescent T-Shaped Excimer
FULL PAPER
THF, or THF/H2O (5:1v/v) solutions of 1 gave blocklike
crystals 1a–c, respectively. Interestingly, although they con-
tained the same molecular composition, the emission prop-
erties of the crystals were different. Crystals of 1a and 1b
emit blue light, whereas those of 1c emit green light upon
UV irradiation (Figure 4 and Supporting Information). Crys-
Figure 4. Solid-state photoluminescence spectra for ground crystals of
1a–c at ambient temperature. (A: 1a, B: 1b, C: 1c; lex =368 nm).
tals 1a and 1b display nearly the same emission spectra with
a structureless monomer emission at 448 nm. Crystals of 1c,
however, show an intense fluorescence emission at lmax
=
500 nm. This remarkable red-shifted emission band is appa-
rently not from a monomer excited state, in contrast to
common anthracene derivatives.[4] Furthermore, the lumi-
nescence of the ground and vacuum-dried powdered crystals
of 1c retained the green-emitting feature, and crystals of 1a
and 1b did not change their emission color on exposure to
air for a long time (>10 days). Thus, the possibility of a sol-
vent-incorporated luminescence change was excluded, in
contrast to other reported solvent-sensitivity luminescent
complexes,[4] but a T-shaped excited-state dimer (excimer)
induced by water during crystallization should be responsi-
ble for the green photoluminescence of 1c, which was also
reminiscent of the emission and the 1H NMR spectral
changes of 1 in H2O/THF solution depicted in Figure 3.
As crystals of 1a and 1b displayed the same characteris-
tic, only good-quality single crystals of 1a were collected for
X-ray structure analysis. The results of the X-ray structure
analysis of L2, 1a, and 1c are shown in Figure 5. The free
ligand L2 crystallizes in an orthorhombic system and adopts
À
a rather interesting dimeric structure with N H···N hydro-
gen bonds (H···N=2.616 Š, N···N=3.182 Š, and N-H-N=
121.78).
Figure 5. X-ray crystal structures of L2, 1a, and 1c. The packing diagram
of 1a is depicted as 1a’, in which x=345.2 pm, y=374.0 pm. Green
sphere: zinc; green ring: hydrogen; gray: carbon; blue: nitrogen; red:
À
À
À
oxygen. Selected data for 1a: Zn1 O11.930(3), Zn1 O3 1.948(3), Zn1
Crystals 1a and 1c adopted different crystallization pat-
terns though both were from the same material. While 1a
crystallized in the triclinic space group P1, 1c crystallized in
the monoclinic space group Cc. In the crystal lattice of 1a,
very weak face-to-face p···p and edge-to-face C H···p-ring
center interactions were observed. The closest centroid–
centroid distance and H···p-ring center distance between an-
thracene rings are 374.0 and 345.2 pm, respectively
À
N12.034(4), Zn1 N2 2.071(3) Š; O1-Zn1-O3 103.99(15), O1-Zn1-N1
123.65(14), O3-Zn1-N1 114.31(14), O1-Zn1-N2 110.47(14), O3-Zn1-N2
¯
À
À
102.37(14), N1-Zn1-N2 100.14(12)8; for 1c: Zn1 O3 1.851(10), Zn1 N2
À
À
À
2.046(9), Zn1 N1 2.114(10), Zn1 O1 2.159(10), Zn1 O2 2.324(13) Š;
O3-Zn1-N2 121.0(5), O3-Zn1-N1 109.8(4), N2-Zn1-N1 95.9(4), O3-Zn1-
O1 103.9(4), N2-Zn1-O1 92.4(4), N1-Zn1-O1 134.2(4), O3-Zn1-O2
117.9(6), N2-Zn1-O2 117.7(5), N1-Zn1-O2 81.9(4), O1-Zn1-O2 54.8(4)8.
À
Chem. Eur. J. 2007, 13, 3630 – 3635
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3633

G. Yang, J. S. Ma et al.
yellow solution was cooled to 508C. An excess of NaBH4 (5.2 g) dis-
solved in CH3OH (15 mL) was added in small portions over 2 h. The
mixture turned increasingly to a clear yellowish color and the resulting
solution was reacted at room temperature overnight. The solvent was re-
moved under reduced pressure, and the residue was treated with excess
water. The undissolved solid was collected by filtration, then recrystal-
lized twice from toluene/ether to give light yellow blocks. Yield: 3.5 g,
65%; m.p. 109–1118C; 1H NMR (300 MHz, CDCl3, 258C, TMS): d=1.62
(brs, 2H; NH), 1.86 (m, 2H; CH2), 2.96 (t, J=6.75 Hz, 4H; CH2), 4.69 (s,
4H; CH2), 7.44 (m, 8H; anthryl-H), 7.96 (d, J=8.0 Hz, 4H; anthryl-H),
8.28 (d, J=9.0 Hz, 4H; anthryl-H), 8.37 ppm (s, 2H; anthryl-H); EIMS:
m/z: 454 [M]+; elemental analysis calcd (%) for C33H31N2·1/2H2O: C
85.49, H 6.74, N 6.04; found: C 85.05, H 7.19, N 6.18.
(Figure 5). Apparently, these weak packing interactions sta-
bilized the crystalline material but the distance was not
short enough to result in the “excimer” emission. Signifi-
cantly, in the crystal lattice of 1c, two isostructural mole-
cules are mutually close, and therein the shortest intermo-
lecular distances of 269.6 and 276.9 pm were observed be-
tween one anthracene center and one edge-ring hydrogen
atom from another molecule. Two adjacent anthracene-ring
planes are of an almost orthogonal arrangement (77.0 and
71.38), thus forming a well-defined T-shaped geometry,
which was apparently responsible for the green light emis-
sion under UV irradiation. The crystallographic analysis
data are also well consistent with the results of 1H NMR
spectroscopic studies in solution. Furthermore, this provides
N,N’-Bis(anthracen-9-ylmethyl)butane-1,4-diamine (L3): 9-Anthracylal-
dehyde (4.7 g, 24 mmol) was dissolved in CH2Cl2/MeOH (60 mL; 1:2 v/v)
and then heated at reflux under N2. A solution of 1,4-diaminobutane
(0.8 mL, 12 mmol) dissolved in CH3OH (10 mL) was subsequently added
dropwise with rigorous stirring. The mixture was refluxed for 4 h and the
yellow solution was cooled to 508C. An excess of NaBH4 (5.0 g) dis-
solved in CH3OH (18 mL) was added in small portions over 2 h. The
mixture turned increasingly to a clear yellowish color and the resulting
solution was reacted at room temperature overnight. The solvent was re-
moved under reduced pressure, and the residue was treated with excess
water. The undissolved solid was collected by filtration, then recrystal-
lized twice from toluene/ether to give pale-yellow blocks. Yield: 3.9 g,
70%; m.p. 116–1178C; 1H NMR (300 MHz, CDCl3, 258C, TMS): d=1.52
(brs, 2H; NH), 1.68 (brs, 4H; CH2), 2.88 (brs, 4H; CH2), 4.69 (s, 4H;
CH2), 7.47 (m, 8H; anthryl-H), 7.99 (d, J=8.1Hz, 4H; anthryl-H), 8.30
(d, J=8.6 Hz, 4H; anthryl-H), 8.39 ppm (s, 2H; anthryl-H); EIMS: m/z:
468 [M]+; elemental analysis calcd (%) for C34H32N2: C 87.14, H 6.88, N
5.98; found: C 87.29, H 6.95, N 5.96.
the first observation of an anthracene–anthracene T-shaped
[12]
À
C H···p interaction which led to an excimer emission.
À
There are only a few examples of T-shaped C H···p interac-
tions observed in excited complexes, such as toluene–ben-
zene[13] and toluene–anthracene.[4,14]
Conclusion
A chain-length-selective approach to water-induced emis-
sion change based on a highly fluorescent inorganic–organic
hybrid material has been studied and established. The re-
markable change of emission characteristic tuned by differ-
ent amounts of water may be regarded as a special type of
chemosensing. Significantly, such dramatic water-induced
on–off switching of emission, and sensitive change in the
emission color of crystals by aggregation of polyaromatic
hydrocarbon and formation of a T-shaped excimer, has not
been previously reported. The complex would perform as a
versatile candidate for chemosensors and probes of environ-
mental changes, and has promising applications in photo-
functional materials as well.
Complex 1: A solution of L2 (454 mg, 1mmol) in CH 2Cl2 (5 mL) was
added to a solution of Zn(OAc)2·2H2O (219 mg, 1 mmol) in CH3OH
G
(5 mL) at ambient temperature. The solution was stirred for 30 min and a
gray precipitate appeared; stirring was continued overnight and the gray
powder was collected by suction filtration. The crude product was recrys-
tallized from THF to give 1 as yellowish blocks. Yield: 522 mg, 82%;
m.p. 220–2218C; 1H NMR (300 MHz, CDCl3, 258C, TMS): d=1.70 (brs,
2H; NH), 2.16 (s, 6H; CH3COO), 2.66 (m, 2H; CH2), 3.27 (m, 2H;
CH2), 3.61(m, 2H; CH ), 4.97 (m, 2H; CH2), 5.16 (m, 2H; CH2), 7.49 (t,
2
J=8.0 Hz, 4H; anthryl-H), 7.59 (t, J=8.3 Hz, 4H; anthryl-H), 8.03 (d,
J=8.4 Hz, 4H; anthryl-H), 8.28 (d, J=8.8 Hz, 4H; anthryl-H), 8.48 ppm
(s, 2H; anthryl-H); EIMS: m/z: 577.3 [1ÀAcO]+; elemental analysis
calcd (%) for C37H36N2O4Zn·1/2H2O·1/2THF: C 68.57, H 6.05, N 4.10;
found: C 68.43, H 5.94, N 4.18.
X-ray crystallography: Accurate unit-cell parameters were determined by
a least-squares fit of 2q values, measured for 200 strong reflections, and
intensity data sets were measured on a Rigarku Raxis Rapid IP diffrac-
tometer with MoKa radiation (l=0.71073 Š) at room temperature. The
intensities were corrected for Lorentz and polarization effects, but no
corrections for extinction were made. All structures were solved by direct
methods. The non-hydrogen atoms were located in successive difference
Fourier synthesis. The final refinement was performed by full-matrix
least-squares methods with anisotropic thermal parameters for non-hy-
drogen atoms on F2. The hydrogen atoms were added theoretically and
riding on the concerned atoms. The crystallographic data and experimen-
tal details of the structure analyses are summarized in Table 1. CCDC-
239341–239343 contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge from the Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Experimental Section
General: Ligand L1 was synthesized by a previously described method.[3c]
All other reagents were commercially available and used without further
purification. Solvents for syntheses were purified according to standard
methods, while for spectra measurement they were purchased as spectro-
photometric grade. Samples for C, H, and N analyses were dried under
vacuum and the analyses were performed with a Carlo Erba 1106 instru-
ment. 1H NMR and 13C NMR spectra were measured with a Bruker dmx
300 or 400 MHz NMR spectrometer at room temperature. The ESI and
MALDI-TOF mass spectrometry (MS) measurements were carried out
with a Bruker APEX II instrument. UV/visible absorption spectra were
obtained on a Hitachi UV-3010 absorption spectrophotometer. Steady-
state excitation and emission spectra were recorded on a Hitachi F-2500
fluorescence spectrophotometer. The fluorescence lifetime was obtained
from a Lifespec-ps fluorescence lifetime analytical spectrometer (Edin-
burgh Instruments).
Acknowledgements
N,N’-Bis(anthracen-9-ylmethyl)propane-1,3-diamine (L2): 9-Anthracylal-
dehyde (4.7 g, 24 mmol) was dissolved in CH2Cl2/MeOH (60 mL; 1:2 v/v)
and then heated at reflux under N2. A solution of 1,3-diaminopropane
(0.8 mL, 12 mmol) dissolved in CH3OH (10 mL) was subsequently added
dropwise with rigorous stirring. The mixture was refluxed for 4 h and the
This work was financially supported by the National Natural Science
Foundation (Nos. 20573122, 20333080, 20372065) and the National Basic
Research Program (2007CB808004).
3634
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3630 – 3635

Fluorescent T-Shaped Excimer
FULL PAPER
Table 1. Crystal and structure refinement data for compounds L2, 1a, and 1c.
[4] For a recent excellent review see:
R. Martínez-MµÇez, F. Sancenón,
Chem. Rev. 2003, 103, 4419, and
references therein.
L2
1a [Zn(L2)
A
1c [Zn2(L2)2(OAc)4·THF·2H2O]
E
empirical formula
Fw
C33H30N2
454.59
C38H38N2O4Cl2Zn
722.97
C78H79N4O11Zn2
1379.2
0.80”0.30”0.13
light yellow
monoclinic
Cc
[5] a) L. Fabbrizzi, M. Licchelli, P.
Pallavicini, L. Parodi, A. Tagliet-
ti, Transition Metals in Supra-
molecular Chemistry, Wiley, New
York, 1999, p. 93; b) P. de Silva,
H. Q. N. Gunaratne, T. Gunn-
laugsson, A. J. M. Huxley, C. P.
McCoy, J. T. Rademacher, T. E.
Rice, Chem. Rev. 1997, 97, 1 51 5;
c) A. P. De Silva, R. A. D. D. Ru-
pasinghe, J. Chem. Soc. Chem.
Commun. 1985, 1669.
[6] a) E. Kimura, S. Aoki, BioMetals
2001, 14, 191; b) S. C. Burdette,
S. J. Lippard, Coord. Chem. Rev.
2001, 216, 333; c) J. A. Sclafani,
M. T. Maranto, T. M. Sisk, S. A.
Van Arman, Tetrahedron Lett.
1996, 37, 2193.
crystal size [mm]
crystal color
crystal system
space group
T [K]
l [Š]
a [Š]
b [Š]
c [Š]
0.56”0.38”0.38
pale yellow
orthorhombic
Pccn
0.20”0.18”0.14
light yellow
triclinic
¯
P1
293(2)
293(2)
0.71073
10.634(10)
11.913(12)
14.390(14)
85.391(16)
69.895(15)
86.052(16)
1705(3)
2
293(2)
0.71073
23.126(5)
25.447(5)
8.3713(17)
90.00
90.00
90.00
4926.4(17)
8
0.71073
11.679(2)
23.864(5)
26.163(5)
90.00
97.57(3)
90.00
7229(2)
4
a [8]
b [8]
g [8]
V [Š3]
Z
F
A
1936
752
2892
1.267
]
1.226
1.408
]
0.0710.921
55015987
2883
317
4.94, 14.54
1.058
0.725
44
4090
426
5.55, 14.64
1.065
reflections collected
unique reflections
variables
81
3598
829
7.95, 21.71
0.946
[7] a) S. Hama, F. Hirayama, J. Phys.
Chem. 1983, 87, 83; b) S. R.
Meech, D. Phillips, J. Photochem.
1983, 23, 193.
R1,[a] wR2[b] [%]
Gof
[a] R=
(FoÀFC)/(Fo). [b] Rw =[w(Fo2ÀF2c)2/w(Fo2)2]1/2
.
[8] a) I. Nordin-Andersson, A. Ce-
dergren, Anal. Chem. 1985, 57,
2571; b) D. Citterio, K. Minami-
hashi, Y. Kuniyoshi, H. Hisamoto,
[1] a) H. B. Rosenstock, J. Chim. Phys. Phys.-Chim. Biol. 1968, 48, 532;
b) A. Matsui, K. Mizuno, M. Kobayashi, J. Phys. Colloq. 1985, 7, 1 9;
S. Sasaki, K. Suzuki, Anal. Chem. 2001, 73, 5339; c) M. Li, G. E.
Pacey, Talanta 1997, 44, 1949; d) A. L. MaÅanita, F. P. Costa, S. M. B.
Costa, E. C. Melo, H. Santos, J. Phys. Chem. 1989, 93, 336.
[9] a) D. Horn, J. Rieger, Angew. Chem. 2001, 113, 4460; Angew. Chem.
Int. Ed. 2001, 40, 4330; b) B.-K. An, S.-K. Kwon, S.-D. Jung, S. Y.
Park, J. Am. Chem. Soc. 2002, 124, 14410; c) S. Li, L. He, F. Xiong,
Y. Li, G. Yang, J. Phys. Chem. B 2004, 108, 10887; d) B. K. An, D. S.
Lee, J. S. Lee, Y. S. Park, H. S. Song, S. Y. Park, J. Am. Chem. Soc.
2004, 126, 10232.
[10] a) T. Hayashi, N. Mataga, Y. Sakata, S. Misumi, N. Morita, J.
Tanaka, J. Am. Chem. Soc. 1976, 98, 5910; b) J. K. McVey, D. M.
Shold, N. C. Yang, J. Chem. Phys. 1976, 65, 3375.
[11] L. S. Kaanumalle, C. L. D. Gibb, B. C. Gibb, V. Ramamurthy, J. Am.
Chem. Soc. 2005, 127, 3674, and references therein.
[12] T. Steiner, Angew. Chem. 2002, 114, 50; Angew. Chem. Int. Ed. 2002,
41, 48.
[13] H. Saigusa, M. Morohoshi, S. Tsuchiya, J. Phys. Chem. A 2001, 105,
7334.
[14] a) H. Saigusa, E. C. Lim, J. Phys. Chem. 1995, 99, 15738; b) T. Chak-
raborty, E. C. Lim, J. Phys. Chem. 1993, 97, 11151.
c) R. C. Ropp, N. J. Warren, Luminescence andthe SolidState
Elsevier, Amsterdam, 1991.
,
[2] a) J. Pang, E. J.-P. Marcotte, C. Seward, R. S. Brown, S. Wang,
Angew. Chem. 2001, 113, 4166; Angew. Chem. Int. Ed. 2001, 40,
4042; b) M. Kato, A. Omura, A. Toshikawa, S. Kishi, Y. Sugumoto,
Angew. Chem. 2002, 114, 3315; Angew. Chem. Int. Ed. 2002, 41,
3183; c) Z. Fei, N. Kocher, C. J. Mohrschladt, H. Ihmels, D. Stalke,
Angew. Chem. 2003, 115, 807; Angew. Chem. Int. Ed. 2003, 42, 783;
d) J. Seo, S. Kim, S. Y. Park, J. Am. Chem. Soc. 2004, 126, 11154.
[3] a) P. Nanjappan, A. W. Czarnik, J. Am. Chem. Soc. 1987, 109, 1826;
b) M. E. Huston, K. W. Haider, A. W. Czarnik, J. Am. Chem. Soc.
1988, 110, 4460; c) S. A. Van Arman, A. W. Czarnik, J. Am. Chem.
Soc. 1990, 112, 5376; d) S.-Y. Hong, A. W. Czarnik, J. Am. Chem.
Soc. 1993, 115, 3330; e) G. De Santis, L. Fabbrizzi, M. Licchelli, A.
Poggi, A. Taglietti, Angew. Chem. 1996, 108, 224; Angew. Chem. Int.
Ed. Engl. 1996, 35, 202; f) L. Fabbrizzi, I. Faravelli, G. Francese, M.
Licchelli, A. Perotti, A. Taglietti, Chem. Commun. 1998, 971; g) L.
Fabbrizzi, M. Licchelli, A. Perrotti, A. Poggi, G. Rabaioli, A. Ta-
glietti, J. Chem. Soc. Perkin Trans. 2 2001, 2108; h) L. Fabbrizzi, M.
Licchelli, F. Mancin, M. Pizzeghello, G. Rabaioli, A. Taglietti, P. Te-
cilla, U. Tonellato, Chem. Eur. J. 2002, 8, 94; i) F. Sancenón, A.
Benito, J. M. Lloris, R. Martínez-MµÇez, T. Pardo, J. Soto, Helv.
Chim. Acta 2002, 85, 1505.
Received: April 11, 2006
Revised: November 17, 2006
Published online: January 22, 2007
Chem. Eur. J. 2007, 13, 3630 – 3635
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3635