The double-helicate terpyridine silver(I) compound [Ag2L2](SO3CF3)2 (L = 4′-phenyl-terpyridine) as a building block for di- and mononuclear complexes

Article abstract of DOI:10.1016/j.ica.2009.01.018

The double-helicate dinuclear silver(I) complex [Ag₂L₂](SO₃CF₃)₂ (1) was obtained by reaction of AgSO₃CF₃ with 4′-phenyl-terpyridine (L). Each Ag⁺ ion is coordinated by two N-atoms from one of the ligands and by one N-atom of the other ligand, forming an irregular Ag₂N₆ bi-triangle geometry, with a metallic bond between the two silver ions. Complex 1 reacts with potentially bidentate ligands (L¹), such as 9,10-bis(diphenylphosphino)anthracene (PAnP), 4,4′-dipyridyl or bis(diphenyl phosphino)methane (DPPM), to give the corresponding dinuclear complexes with bridging L¹, [Ag₂L₂(μ-L¹)](SO₃CF₃)₂ (L¹ = PAnP 2, 4,4′-dipyridyl 3 or DPPM 4), whereas on reaction with PPh₃ forms the mononuclear complex [AgL(PPh₃)](SO₃CF₃) 5. Reaction of 1 with the potentially tridentate ligand tris(2-diphenylphosphinoethyl)amine (NP₃) results in complete decomposition of the coordination spheres to form [Ag(NP₃)](SO₃CF₃) 6. Compound 1 shows a strong fluorescence in the solid state with its excitation band at 383.5 nm, the emission band at 535.5 nm and the lifetime of 4.20 ns, but the derived complexes do not show fluorescent properties. The photoluminescence of 1 in various solvents was also studied. The complexes were characterized by ¹H NMR, elemental analysis, IR, MS, UV and single crystal X-ray diffraction.

Full text of DOI:10.1016/j.ica.2009.01.018

Inorganica Chimica Acta 362 (2009) 2921–2926
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Inorganica Chimica Acta
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The double-helicate terpyridine silver(I) compound [Ag2L2](SO3CF3)2
(L = 40-phenyl-terpyridine) as a building block for di- and mononuclear complexes
a
a
a
a
c,d
Zhen Ma a,b, , Yanpeng Xing , Mei Yang , Miao Hu , Baoqing Liu , M. Fátima C. Guedes da Silva
,
*
Armando J.L. Pombeiro c,
*
a School of Chemistry and Chemical Engineering, Guangxi University, Guangxi 530004, China
b State Key Laboratory, Fujian Institute of Research on the Structure of Matter, Fuzhou, Fujian 350002, China
c Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1049-001, Lisbon, Portugal
d Universidade Lusófona de Humanidades e Tecnologias, ULHT Lisbon, Av. do Campo Grande, 376, 1749-024, Lisbon, Portugal
a r t i c l e i n f o
a b s t r a c t
Article history:
The double-helicate dinuclear silver(I) complex [Ag2L2](SO3CF3)2 (1) was obtained by reaction of
AgSO3CF3 with 40-phenyl-terpyridine (L). Each Ag+ ion is coordinated by two N-atoms from one of the
ligands and by one N-atom of the other ligand, forming an irregular Ag2N6 bi-triangle geometry, with
a metallic bond between the two silver ions. Complex 1 reacts with potentially bidentate ligands (L1),
such as 9,10-bis(diphenylphosphino)anthracene (PAnP), 4,40-dipyridyl or bis(diphenyl phosphino)meth-
Received 15 October 2008
Received in revised form 12 January 2009
Accepted 21 January 2009
Available online 31 January 2009
ane (DPPM), to give the corresponding dinuclear complexes with bridging L1, [Ag2L2( -L1)](SO3CF3)2
l
Keywords:
Silver(I) complexes
Coordination
Crystal structure
Luminescent properties
(L1 = PAnP 2, 4,40-dipyridyl 3 or DPPM 4), whereas on reaction with PPh3 forms the mononuclear complex
[AgL(PPh3)](SO3CF3) 5. Reaction of 1 with the potentially tridentate ligand tris(2-diphenylphosphino-
ethyl)amine (NP3) results in complete decomposition of the coordination spheres to form [Ag(NP3)]-
(SO3CF3) 6. Compound 1 shows a strong fluorescence in the solid state with its excitation band at
383.5 nm, the emission band at 535.5 nm and the lifetime of 4.20 ns, but the derived complexes do
not show fluorescent properties. The photoluminescence of 1 in various solvents was also studied. The
complexes were characterized by 1H NMR, elemental analysis, IR, MS, UV and single crystal X-ray
diffraction.
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
silver complexes with a terpyridine ligand, 40-phenyl-terpyridine,
by testing the [Ag2(40-Ph-terpy)2]2+ site as a suitable starting mate-
Much current attention has been paid to multi-pyridyl com-
plexes [1–9] due to their properties in photoluminescence and
catalysis, and their interest as sensors and in molecular electronics.
Ligation of these multi-pyridyl ligands to transition metal ions,
especially platinum, forming square coordination geometries,
shows a rich range of spectroscopic and photo-luminescent prop-
erties, as well as the propensity to exhibit metal–metal interac-
tions. Ag+ can also form a diversity of structures including stable
planar complexes with tri- [10–13], penta- [14,15] and hexa-
[16] dentate multi-pyridyl ligands and in a few cases there is a me-
tal–metal bond between two central ions forming double-helicate
complexes [11a]. Although the crystal structures of these types of
complexes, namely of helical silver species, and their electrical and
catalytic properties were studied, their photo-luminescent proper-
ties have only seldom been reported [11b] and their reactivity has
still been little explored. Hence, the current work aims to prepare
rial, and to investigate their photo-luminescent behaviour.
In this paper, we report the preparation and characterization of
the dinuclear helicate compound [Ag2L2](SO3CF3)2 1 (L = 40-Ph-ter-
py). It was obtained by reaction of 40-phenyl-terpyridine with
AgSO3CF3 in mixed CH2Cl2 and CH3CN solvents and its solid state
structure (as shown by single crystal X-ray diffraction) displays
two twisted coordination triangles, with each Ag+ coordinated by
three N atoms (two from one of the ligands and the third N from
the other one). This configuration makes possible a metal–metal
bond between the two central metal ions. Its fluorescent properties
were also studied. By reaction with several N- or P-compounds, it
undergoes a structural rearrangement with Ag–Ag bond cleavage
to afford five new complexes which were isolated and character-
ized by 1H NMR, IR and electronic spectroscopies, elemental anal-
ysis, MS and single crystal X-ray diffraction.
2. Results and discussion
* Corresponding authors.
E-mail addresses: mzmz2009@sohu.com (Z. Ma), pombeiro@ist.utl.pt
The double-helicate silver(I) complex [Ag2L2](SO3CF3)2
(1, L = 4’-Ph-terpy) was synthesized by treatment of a CH2Cl2
(A.J.L. Pombeiro).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.01.018

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Z. Ma et al. / Inorganica Chimica Acta 362 (2009) 2921–2926
Table 1
Crystal data for the title compounds.
Compounds
Formula
1
2
3
4
5
6
C
C44H30Ag2-
F6N6O6S2
1132.60
monoclinic
C2/c
19.6347(8)
18.132(1)
14.6506(6)
90
124.567(1)
90
4295.0(3)
4
C83H58Ag2Cl2-
F6N6O6P2S2
1762.05
triclinic
C54H38Ag2-
F6N8O6S2
1288.78
monoclinic
P2(1)/n
8.5373(3)
15.8799(7)
18.5540(6)
90
93.398(1)
90
2516.8(2)
2
C75H67Ag2F6-
N6O7.50P2S2
1628.15
monoclinic
P2(1)/c
13.4086(8)
24.4640(19)
23.5042(12)
90
106.114(2)
90
7407.1(8)
4
C40H30AgF3-
N3O3PS
828.57
Triclinic
43H42AgF3-
NO3P3S
910.62
Trigonal
P32
17.740(3)
17.740(3)
11.446(2)
90
90
120
3119.5(9)
3
1.454
Formula Weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
ꢀ
ꢀ
P1
P1
9.5175(6)
15.241(1)
15.884(1)
117.807(2)
90.632(3)
98.294(4)
2008.6(3)
1
10.4936(8)
12.4263(9)
15.1431(9)
104.929(2)
92.541(4)
108.099(3)
1796.9(2)
2
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (Mg mꢁ3
)
1.752
1.092
1.457
0.716
1.701
0.945
1.460
0.701
1.531
0.723
l
(mmꢁ1
)
0.703
Independent reflection,
observed reflection
4930, 4332
8622, 7339
5450, 4498
12711, 9521
8036, 7305
4768, 3800
Goodness-of-fit (GOF)
1.012
1.052
1.072
1.042
1.057
1.033
R1 [I > 2
wR2
r
(I)]
0.0347
0.0995
0.0487
0.1373
0.0304
0.0920
0.0792
0.2452
0.0338
0.0956
0.0254
0.0675
solution of L with a CH3CN solution of AgSO3CF3. It was isolated as
a colourless crystalline solid which was characterized by 1H NMR,
IR, MS, elemental and X-ray diffraction analyses. Details of the
crystal parameters, data collections and refinements are summa-
rized in Table 1.
the mononuclear complex 6, with liberation of the L ligand which
was isolated, in accord with the stoichiometry of 6.
The stability in solution of the bridged compounds depends on
the non-terpyridine ligand and in air it tracks the following se-
quence: 1 > 3 > 4 > 2. Hence, in DMSO solution under air, at room
temperature, compound 2 decomposes within one day while the
others take several weeks. Additionally, the stability of complexes
5 and 6 are similar to those of 3 and 1, respectively. Moreover, even
under inert atmosphere, the formation of silver mirrors on the
walls of the containers occurs in several months, for all the
compounds.
Compound 1 crystallized in a centrosymmetric space group and
both left and right helicates are present in the solid state as shown
in Fig. 1a. Each silver ion is coordinated by three pyridyl groups
from two ligands and each terpyridyl ligand bridges two Ag(I)
atoms acting as a bidentate ligand to one of the metal atoms and
in a monodentate mode to the other one. Each silver ion displays
one shorter Ag1–N1 bond to one pyridine ring of one ligand
(2.273(2) Å) and two longer contacts (Ag1–N2 and Ag1–N3) to
two pyridyl rings (2.331(2) and 2.394(2) Å, respectively) of the
other ligand, forming an irregular triangle coordination geometry.
A disilver head-to-head double-helicate is present with a Ag–Ag
distance of 2.9452(4) Å in the dinuclear cation, considerably short-
er than the sum of the van der Waals radii (3.40 Å). This distance is
even shorter than that reported, 3.170(1) Å, for [Ag2(tpy)2
(MeCN)2][PF6]2 [11a], although longer than those (2.8955(6)–
2.8441(7) Å range) of [Ag2L2]2[PF6]4ꢀ(CH3COCH3)2 (L = 40-phenyl-
2,20:60,200-terpyridine) [11b]. However, while in this case the
tetranuclear cations are further aggregated through Agꢀ ꢀ ꢀAg
intermolecular contacts of 3.215 Å (also shorter than the sum of
van der Waals radii, see above), in compound 1 the shortest
intermolecular metal contact is 7.638 Å.
The obtained compound 1 in solid state is in its stable dinuclear
(2Ag:2L) form, which is the only one isolated whether the silver
salt solution was added to the 40-Ph-terpy solution or the reverse.
The corresponding mononuclear 1:1 (Ag:L) form of this complex
was not obtained under these conditions. Constable et al. reported
[11a] the two related silver compounds with multi-pyridyl
ligands [Ag2(tpy)2(MeCN)2][PF6]2 (tpy = 2,20:60,200-terpyridine) and
[Ag(dptpy)(MeCN)][BF4] (dptpy = 6,600-diphenyl-2,20:60,200-terpyri-
dine), while Hou et al. reported [11b] the tetranuclear compound
[Ag2L2]2[PF6]4ꢀ(CH3COCH3)2 with the same 40-phenyl-terpyridine
ligand of our study. The molecular structure of [Ag2(tpy)2-
(MeCN)2][PF6]2 [11a] displays a metal–metal bond between the
two metal ions whose coordination geometry is square-planar. In
the structure of [Ag2L2]2[PF6]4ꢀ(CH3COCH3)2 [11b], two double-
helicate dinuclear subunits are linked by a ligand-unsupported
Ag–Ag bond and each terpyridyl bridging two Ag(I) atoms acts as
a bi- and a monodentate ligand. One Ag(I) atom is four-coordinate
and the other is two-coordinate. By comparison of these with our
results, we can conclude that the observed differences are not only
caused by a variation of the ligands but also by the distinct syn-
thetic processes that were used. Depending on the experimental
conditions, terpyridine ligands and counterions, different struc-
tures of the terpyridine silver compounds can be obtained [13].
Upon reaction of 1 with an aromatic phosphine or 4,40-dipyri-
dyl, the Ag–Ag bond is broken and the dinuclear 2:2 (Ag+:4’-Ph-ter-
py) structure rearranges to the mononuclear 1:1 form. In fact, as
illustrated in Scheme 1, compound 1 reacts with P- or N-species,
such as PAnP, 4,40-dipyridyl, DPPM, PPh3 or NP3, yielding products
with coordination spheres (AgN3P or AgN4) that are different from
the initial one (Ag2N6). Reactions with potentially bidentate li-
As shown by the X-ray crystal structural analysis, complex 2 is
dinuclear with each silver ion coordinated by three N atoms from
40-Ph-terpy and one P atom of PAnP, forming an irregular tetrahe-
dral AgN3P coordination structure as shown in Fig. 1b. The two
AgL+ groups are bridged by the PAnP ligand, while the two 40-Ph-
terpy (L) units are parallel to each other, accounting for the sym-
metry of this complex. The lengths of the Ag1–N1, Ag1–N2 and
Ag1–N3 bonds [2.460(3), 2.396(3) and 2.443(3) Å, respectively]
are not much different, being slightly shorter than that of Ag1–
P1, 2.4799(8) Å, suggesting a stronger coordination of the tripodal
40-Ph-terpy ligand than that of PAnP. The distances between the
gands (L1) give the corresponding dinuclear complexes [Ag2L2(
L1)](SO3CF3)2 (L1 = PAnP 2, l0-dipyridyl 3 or DPPM 4), while the
l,
l-
reaction with a monophosphine (L2), such as PPh3, affords the
mononuclear compound [AgL(L2)](SO3CF3) 5. However, upon reac-
tion of 1 with the potentially tridentate ligand NP3, displacement
of the coordinated 40-Ph-terpy occurs to form the mononuclear
NP3 complex [AgL3](SO3CF3) 6. When a 1:NP3 ratio of 3:2 is used
(corresponding to 3Ag:1NP3), only one third of 1 reacts to form

Z. Ma et al. / Inorganica Chimica Acta 362 (2009) 2921–2926
2923
Ph
N
PPh2
PPh2
Ph2P
PPh2
N
N
N
PPh2
L = 4'-Ph-terpy
PAnP
NP3
Ligands
(SO3CF3)2
(SO3CF3)2
N
N
N
N
L1
L1
Ag
N
Ag
N
Ag
Ag
N
N
N
N
N
N
(L1 = PAnP 2, 4,4'-dipyridyl 3, DPPM 4)
1
(SO3CF3)
L2
N
(L2 = PPh3, 5)
L2
Ag
N
N
L3
-L
(L3 = NP3)
[AgL3]( SO3CF3) (6)
Scheme 1. Reactions of [Ag2L2](SO3CF3)2 1 to form complexes with P- or N-ligands.
two central metal ions and the two P atoms are 10.2874(7) and
6.576(2) Å, respectively, the former being longer than those of
Au–Au in complex [{AuX}2(l-PAnP)] (X = Cl, Br) [9.154(2),
The metal ion is coordinated by three N and one P atoms (AgN3P
coordination form as in complex 2). The average distance of
Ag–N in complex 5 (2.449 Å) is identical to that in complex 4
(2.455 Å), so does the Ag–P bond length [2.3849(5) Å for 5;
2.399(2) and 2.402(2) Å for 4]. For 2, the Ag–P distance
(2.4799(8) Å) is longer than that in complexes 4 and 5, while the
average Ag–N bond length (2.433 Å) is shorter than in the latter
complexes, what conceivably reflects the high steric hindrance of
the anthracenyl group of the PAnP ligand.
9.091(4), 7.737(2) and 7.768(1) Å] [17] with a more open coordina-
tion sphere. The AgN3P tetrahedron is distorted with P–Ag–N an-
ꢁ
gles of 103.50(7), 130.88(6) and 112.59(8)°. The SO3CF3 ions
have weak contacts, 2.734(6) Å, with the central Ag+ ions, via an
oxygen donor atom. The anthracenyl rings do not curve from cen-
tral ions in contrast to what was reported [17] for the above Au
complexes.
Complex 6 crystallizes in the trigonal system in the chiral space
group P32. The Flack parameter is 0.56(3) here, and 0.44(3) for the
inverted structure therefore showing that racemic twinning is
present. The compound is mononuclear as shown in Fig 1f, with
the silver ion coordinated to the three phosphorus atoms of the
In complex 3 (Fig. 1c), each Ag+ ion is coordinated by three N
atoms from 40-Ph-terpy and one N atom from 4,40-dipyridyl, in a
distorted tetrahedral geometry, as for complex 2. The coordination
bond length 2.233(2) Å of 4,40-dipyridyl, Ag1–N4, is shorter than
those of phenyl-terpyridine [i.e. 2.533(2), 2.376(2) and
2.318(2) Å, for Ag1–N1, Ag1–N2 and Ag1–N3, respectively], indi-
cating a slightly stronger coordination of the former chelating li-
gand. The three N4–Ag1–N angles of 133.58(7), 153.82(7) and
90.88(7)° are also indicative of the distortion of the AgN4 coordina-
tion tetrahedron, as in the structure of 2.
ꢁ
NP3 ligand and presenting an Ag1–O1 (of the SO3CF3 counter-
ion) contact distance of 2.756(4) Å, thus completing a distorted tet-
rahedron around the silver atom. The P–Ag1–P angles (average
114.25°) deviate by a maximum of 9° from the ideal value of
109° as a consequence of the lack of ligand requirements in the
fourth coordination position of silver. The Ag–P bond lengths
(average 2.4764 Å) are within the overall range of values encoun-
tered in the aforementioned Ag complexes. The oxygens and the
Complex 4 is also a dinuclear species as shown in Fig. 1d. Two
(AgL)+ building blocks are coordinated by the P atoms of the bridg-
ing DPPM molecule, in a distorted tetrahedral geometry, as for
complex 3. Unlike the structures of 2 and 3, the two (AgL)+ struc-
tures are in the cis conformation and nearly parallel, by the effect
of the bridging ligand. There is a Ag–Ag contact of 3.1575(7) Å be-
tween the two central metal ions. The distance between the two P
atoms is 3.043(2) Å, being longer than that [2.970 or 2.988 Å] of the
free ligand [18].
ꢁ
fluorines in the SO3CF3 counter-ion participate in the formation
of four long (non-classic) hydrogen bonds (with phenyl-H atoms,
Dꢀ ꢀ ꢀA bond distances between 3.150 and 3.371 Å), which help to
stabilize the structure.
As illustrated in Fig. 2, compound 1 in the solid state shows
strong fluorescent properties, with an excitation band at
383.5 nm, an emission band at 535.5 nm and
a
lifetime of
r transitions
*
Complex 5 is mononuclear with a distorted square geometry as
4.20 ns. The fluorescence may be assigned to d
r
ꢁ p
shown in Fig. 1e, bearing a PPh3 coordinated to the (AgL)+ centre.
as reported [19,20] for similar discrete d10 gold–gold dimers. The

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Z. Ma et al. / Inorganica Chimica Acta 362 (2009) 2921–2926
Fig. 1. A view of the complex cations of [Ag2L2](SO3CF3)2 (1) (a), [Ag2L2(PAnP)](SO3CF3)2 (2) (b), [Ag2L2(4,40-dipyridyl)](SO3CF3)2 (3) (c), [Ag2L2(DPPM)](SO3CF3)2 (4) (d) and
[AgL(PPh3)](SO3CF3) (5) (e), as well as of [Ag(NP3)](SO3CF3) (6) (f), showing the atom labelling schemes. The ellipsoids are drawn at the 50% probability level and the H atoms
have been omitted for clarity. Ag-ligand bonds are indicated by solid lines.
fluorescence is quenched upon Ag–Ag bond cleavage, and thus is
not observed in any of the derived mononuclear complexes in their
solid state or solution in several solvents, such as methanol, aceto-
nitrile or DMF, at ambient or even at low temperature (77 K). In
addition, although there is also a Ag–Ag contact in complex 4, no
emission of fluorescence is detected in the conditions mentioned
above. This phenomenon may be accounted for by the longer dis-
tance between the two central ions in complex 4 (3.1575(7) Å)
than in complex 1 (2.9452(4) Å), or may result from the coordina-
tion differences in the two complexes (AgN3 in 1 and AgN3P in 4).
The photo-luminescent properties of compound 1 in methanol,
acetonitrile (CH3CN), dimethylformamide (DMF), dimethylsulph-
oxide (DMSO) and ethanol solutions were also studied and the re-
sults are listed in Table 2. It is noteworthy to mention that the
Stoke’s shifts and the fluorescent intensities increase with the in-
crease of the solvent polarity. The sequence of the Stoke’s shifts
is as follows: methanol (233 and 295 nm for peak one and two,
respectively) ꢂ CH3CN (231 and 294 nm for peak one and
two, respectively) > DMF (127 nm) ꢂ DMSO (125 nm) > ethanol
(20 nm). The increase of the polarity of the solvent leads to a red
shift of the excitation and emission peaks. There are two peaks of
emission in the spectra in methanol and acetonitrile due to the
strong polarity of these solvents.
3. Experimental
3.1. Instruments
3.1.1. Physical measurements
Collections of single crystal X-ray data were performed at 293 K
on a Rigaku R-AXIS RAPID Weissenberg IP Diffractometer with
graphite-monochromated MoK
a
radiation (k = 0.71073 Å). 1H
NMR spectra were run on a Varian Unity 500 spectrometer. Ele-
mental analyses were determined with an Elementar Vario EL III
Elemental Analyser. IR spectra were measured with a Perkin–Elmer
Spectrum 2000 or a Magna750 FT-IR spectrophotometer, in KBr

Z. Ma et al. / Inorganica Chimica Acta 362 (2009) 2921–2926
2925
undertaken under argon. Anal. Calc. for [Ag2C42H30N6](SO3CF3)2:
C, 46.66; H, 2.67; N, 7.42. Found: C, 46.76; H, 2.27; N, 7.41%. 1H
NMR d (DMSO-d6): 7.60 (d, 4H), 7.61 (d, 4H), 7.65 (d, 2H), 8.12
(d, 4H), 8.15 (d, 4H), 8.59 (d, 4H), 8.68 (d, 4H), 8.76 (s, 4H). IR
(KBr disk) (cmꢁ1): 3063 (m), 1607 (s), 1595 (s), 1568 (m), 1548
(m), 1477 (s), 1409 (s), 1246 (vs, br), 1163 (s, br), 1028 (s), 1009
(s), 893 (m), 794 (s), 766 (s), 698 (s), 636 (s), 517 (s). UV (CH3OH):
535.5
kmax = 279.5 nm,
e
max = 5.2 ꢃ 104 L cmꢁ1 molꢁ1. ESI-MS: [Ag2L2]2+
(419.1, 96%), [Ag2L2(SO3CF3)]+ (983.2, 100%).
3.2.2. [Ag2L2(PAnP)](SO3CF3)2 (2)
[Ag2L2](SO3CF3)2 (0.150 g, 0.132 mmol) and PAnP (0.072 g,
0.132 mmol) were dissolved in 20 mL of CH2Cl2 and the solution
was stirred for 48 h under argon. After concentration and separa-
tion by column chromatography (silica gel; CH2Cl2:MeOH 10:1),
a yellow powder of 2 was obtained (0.168 g, yield 66%) upon con-
centration of the elute. It was recrystallized from acetonitrile by
diffusion of diethyl ether, leading to yellow crystals, which were
suitable for X-ray characterization. Elemental Anal. Calc. for
[Ag2C80H58N6P2](SO3CF3)2: C, 58.65; H, 3.48; N, 5.00. Found: C,
58.49; H, 3.17; N, 4.50%. 1H NMR d (DMSO-d6): 6.86 (s, 4H), 7.42
(t, 20H), 7.54 (s, 2H), 7.62 (d, 8H), 7.97 (s, 4H), 8.01 (d, 4H), 8.10
(d, 4H), 8.33 (s, 4H), 8.66 (d, 4H), 8.74 (s, 4H). IR (KBr disk)
(cmꢁ1): 3059 (m), 1605 (s), 1571 (m), 1548 (m), 1548 (m), 1473
(m), 1437 (m), 1406(m), 1276 (vs,br), 1262 (vs,br), 1224(m),
1157(s), 1098 (m), 1031 (s), 794 (m), 764 (s), 753 (s), 696 (s),
638 (s), 554(m), 517 (s). UV (CH2Cl2): kmax = 267.3 nm,
450
500
550
600
650
700
λ/nm
Fig. 2. The fluorescent emission band of compound 1 (excited at 383.5 nm).
Table 2
Photo-luminescent data of compound 1 in solutionsa.
Solvent
CH3OH
CH3CN
DMF
DMSO
CH3CH2OH
Ex (nm)
Em (nm)
415
648, 710
415
646, 709
377
504
380
505
345
365
e
max = 1.0 ꢃ 105 L cmꢁ1 molꢁ1
.
ESI-MS:
[Ag2L2(PAnP)]2+
a
Ex = excitation band; Em = emission band.
(688.0, 28%).
pellets. Electrospray mass spectra (ESI-MS) were recorded on a
Finnigan LCQ Mass Spectrometer using dimethylformamide–meth-
anol, methanol, dichloromethane–methanol or acetonitrile–meth-
anol as the mobile phase. Emission and excitation spectra were
recorded on a Perkin–Elmer LS 55 luminescence spectrometer with
a red-sensitive photomultiplier type R928. Emission lifetimes were
determined on an Edinburgh Analytical Instruments F900 fluores-
cence spectrometer using an LED laser at 397 nm excitation, and
the resulting emission was detected by a thermoelectrically cooled
Hamamatsu R3809 photomultiplier tube. The instrument response
function at the excitation wavelength was deconvolved from the
luminescence decay. UV–Vis absorption spectra in acetonitrile
and dichloromethane solutions were measured on a Perkin–Elmer
Lambda 25 UV–Vis spectrometer. All reagents used in the experi-
ments were of analytical grade or purified by standard methods.
4,40-dipyridyl and PPh3 were purchased from Acros and used as
received.
3.2.3. [Ag2L2(4,40-dipyridyl)](SO3CF3)2 (3)
[Ag2L2](SO3CF3)2 (0.183 g, 0.162 mmol) and 4,40-dipyridyl
(0.025 g, 0.162 mmol) were dissolved in 20 mL of CH2Cl2 and
20 mL of CH3CN and the solution was stirred for 48 h under argon.
Upon column chromatography separation (silica gel; first CH2Cl2,
then CH2Cl2:MeOH 5:1), the obtained solution was diffused with
diethyl ether and the obtained colourless crystals (0.113 g, 54%
yield) were suitable for X-ray characterization. Anal. Calc.
[Ag2C52H38N8](SO3CF3)2: C, 50.33; H, 2.97; N, 8.69. Found: C,
50.68; H, 3.22; N, 8.87%. 1H NMR d (DMSO-d6): 7.59 (m, 4H),
7.62 (s, 2H), 7.65 (d, 4H), 7.86 (m, 4H), 8.12 (t, 4H), 8.16 (d, 4H),
8.57 (d, 4H), 8.68 (d, 4H), 8.74 (m, 4H), 8.75 (s, 4H). IR (KBr disk)
(cmꢁ1): 3073 (m), 1597 (s), 1585 (m), 1575(m), 1547 (m), 1475
(s), 1410 (m), 1393 (m), 1264 (vs, br), 1221 (m), 1154 (s, br),
1027 (s), 1003 (m), 812 (m), 771 (s), 728 (m), 699 (m), 636 (s),
517 (m). UV (CH2Cl2): kmax = 287.5 nm,
e
= 6.9 ꢃ 104 L cmꢁ1 molꢁ1
.
ESI-MS: [Ag2L2(4,40-dipyridyl)]2+ (495.8, 32%).
3.2. Synthesis
3.2.4. [Ag2L2(DPPM)](SO3CF3)2 (4)
[Ag2L2](SO3CF3)2 (0.182 g, 0.161 mmol) and DPPM (0.062 g,
0.16 mmol) were dissolved in CH2Cl2 (40 mL) and the solution stir-
red for 48 h under argon. It was filtered and purified by column
chromatography (silica gel; CHCl3:MeOH 20:1) and a white pow-
der of 4 was obtained (0.140 g, 57% yield) upon concentration.
The solid was recrystallized from acetonitrile by diffusion of
diethyl ether, yielding colourless crystals which were suitable for
X-ray characterization. Anal. Calc. for [Ag2C67H52N6P2]-
(SO3CF3)2 ꢀ 0.5CHCl3: C, 52.94; H, 3.36; N, 5.33. Found: C, 52.92;
H, 3.56; N, 4.81%. 1H NMR d (DMSO-d6): 3.89 (s, 2H), 7.27 (s,
10H), 7.37 (s, 4H), 7.45 (s, 4H), 7.60 (s, 14H), 8.01 (s, 8H), 8.45 (t,
4H), 8.61 (t, 8H). ESI-MS: [Ag2L2(DPPM)](SO3CF3)+ (1367.3, 100%),
[Ag2L2(DPPM)]2+ (611.5, 2%).
Ligands: 40-Ph-terpy [21], 9,10-bis(diphenylphosphino)anthra-
cene (PAnP) [22], bis(diphenylphosphino)methane (DPPM) [23],
and tris(2-diphenylphosphinoethyl)amine (NP3) [23] were pre-
pared by the reported procedures.
3.2.1. [Ag2L2](SO3CF3)2 (1)
Dissolution of 40-Ph-terpy (0.816 g, 2.64 mmol) in CH2Cl2
(25 mL) was followed by the slow addition (half an hour) of an
CH3CN solution (25 mL) of AgSO3CF3 (0.677 g, 2.64 mmol), under
argon. The resulting solution was stirred for 8 h and then refluxed
for 5 h. After being concentrated, diethyl ether was added until a
large amount of a white solid formed, which was filtered off and
washed twice with diethyl ether. This white powder of the product
1 (1.22 g, yield 82%) was recrystallized from acetonitrile by diffu-
sion of diethyl ether to yield colourless crystals, which were suit-
able for X-ray characterization. All the synthetic processes were
3.2.5. [AgL(PPh3)](SO3CF3) (5)
[Ag2L2](SO3CF3)2 (0.140 g, 0.124 mmol) and PPh3 (0.065 g,
0.248 mmol) were dissolved in CH2Cl2 (30 mL) and the solution

2926
Z. Ma et al. / Inorganica Chimica Acta 362 (2009) 2921–2926
stirred for 48 h under argon. It was then diffused with diethyl ether
and colourless crystals were obtained (0.098 g). Evaporating the
left-over solution gave more product (0.077 g) (85% total yield).
The solid was recrystallized from acetonitrile by diffusion of
diethyl ether, forming colourless crystals which were suitable for
X-ray characterization. Anal. Calc. for [AgC39H30N3P](SO3CF3): C,
57.98; H, 3.65; N, 5.07. Found: C, 57.86; H, 3.22; N, 5.07%. 1H
NMR d (DMSO-d6): 7.31 (t, 6H), 7.46 (d, 6H), 7.52 (s, 3H), 7.53 (s,
2H), 7.60–7.65 (m, 3H), 8.08 (t, 2H), 8.15 (d, 2H), 8.47 (d, 2H),
8.73 (d, 2H), 8.80 (s, 2H). ESI-MS: [AgL(PPh3)]+ (679.8, 94%).
Acknowledgements
The authors are grateful for financial support from the Founda-
tion for Science and Technology (FCT) of Portugal and its POCI pro-
gramme (FEDER funded) (Grant No. SFRH/BPD/24691/2005), the
innovation fund of Fujian Province (2003J044) and the Scientific
Fund of Guangxi University (X061144).
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4. Supplementary material
CCDC 705121, 705122, 705123, 705124, 705125 and 705126
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.
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