Organometallic coordination polymers generated from bent bis(acetylenylphenyl)oxadiazole ligands and Ag(I) salts

Article abstract of DOI:10.1021/ic0508223

Two new bent oxadiazole bridging benzoacetylene ligands 2,5-bis(4-ethynylphenyl)-1,3,4-oxadiazole (L9) and 2,5-bis(3-ethynylphenyl)-1,3, 4-oxadiazole (L10) were synthesized. The coordination chemistry of them with various inorganic Ag(I) salts has been investigated. Seven new coordination polymers were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. [Ag₂(L9)]-(SO₃CF₃)₂ (1) (triclinic, P1; a = 10.292(4), b = 10.794(4), c = 11.399(5) A; α = 98.894(5), β = 102.360(6), γ = 90.319(5)°; Z = 2), [Ag(L9)]SbF₆ (2) (orthorhombic, Cmca; a = 19.059(9), b = 12.922(6), c = 15.609(7) A; Z = 8), [Ag(L9)]BF₄ (3) (orthorhombic, Cmca; a = 19.128(3), b = 12.6042(18), c = 28.003(4) A; Z = 16), [Ag(L9)]ClO₄ (4) (monoclinic, P2₁/c; a = 8.5153(16), b = 19.722(4), c = 10.320(2) A; β = 105.307(3)°; Z = 4), [Ag(L10)]-SO₃CF ₃ (5) (triclinic, P1; a = 9.0605(13), b = 10.4956(15), c = 10.8085(16) A; α = 101.666(2), β = 109.269(2), γ = 100.944(2)°; Z = 2), [Ag(L10)(H₂O)_0.5]BF ₄·0.5H₂O (6) (monoclinic, C2/m; a = 32.180(6), b = 17.027(3), c = 8.1453(15) A; β = 102.541(3)°; Z = 8), and {[Ag₂(L10)₂(H₂O)](ClO₄) ₂}·o-xylene (7) (monoclinic, P2₁/c; a = 8.1460(10), b = 17.326(2), c = 30.345(4) A; β = 97.71°; Z = 4) were obtained by the combination of L9 and L10 with various Ag(I) salts in a benzene/methylene chloride mixed solvent system. In addition, the luminescent and electrical conductive properties of these new compounds were investigated.

Full text of DOI:10.1021/ic0508223

Inorg. Chem. 2005, 44, 6591−6608
Organometallic Coordination Polymers Generated from Bent
Bis(acetylenylphenyl)oxadiazole Ligands and Ag(I) Salts
Yu-Bin Dong,* Qiang Zhang, Le Wang, Jian-Ping Ma, Ru-Qi Huang, Da-Zhong Shen, and
De-Zhan Chen
College of Chemistry, Chemical Engineering and Materials Science, and Shandong Key Lab of
Chemical Functional Materials, Shandong Normal UniVersity, Jinan 250014, P. R. China
Received May 21, 2005
Two new bent oxadiazole bridging benzoacetylene ligands 2,5-bis(4-ethynylphenyl)-1,3,4-oxadiazole (L9) and 2,5-
bis(3-ethynylphenyl)-1,3,4-oxadiazole (L10) were synthesized. The coordination chemistry of them with various
inorganic Ag(I) salts has been investigated. Seven new coordination polymers were prepared by solution reactions
and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. [Ag2(L9)]-
(SO3CF3)2 (1) (triclinic, P1
90.319(5) ; Z 2), [Ag(L9)]SbF6 (2) (orthorhombic, Cmca; a
8), [Ag(L9)]BF4 (3) (orthorhombic, Cmca; a
(4) (monoclinic, P21/c; a 8.5153(16), b
SO3CF3 (5) (triclinic, P1; a 9.0605(13), b
γ ) 100.944(2) ; Z 2), [Ag(L10)(H2O)0.5]BF4
8.1453(15) Å; â ) 102.541(3) ; Z 8), and
8.1460(10), b 17.326(2), c 30.345(4) Å; â ) 97.71
h; a )10.292(4), b ) 10.794(4), c ) 11.399(5) Å; R ) 98.894(5), â ) 102.360(6), γ )
°
)
)
19.059(9), b
12.6042(18), c
10.320(2) Å; â ) 105.307(3)
)
12.922(6), c
)
)
; Z )
15.609(7) Å; Z
16), [Ag(L9)]ClO4
4), [Ag(L10)]-
)
)
)
19.128(3), b
19.722(4), c
)
)
) 28.003(4) Å; Z
)
°
h
)
)
)
10.4956(15), c
0.5H2O (6) (monoclinic, C2/m; a
[Ag2(L10)2(H2O)](ClO4)2}‚o-xylene (7) (monoclinic, P21/c; a
; Z
) 10.8085(16) Å; R ) 101.666(2), â ) 109.269(2),
°
‚
)
32.180(6), b
)
17.027(3), c
)
)
°
)
)
{
)
°
)
4) were obtained by the combination of L9 and
L10 with various Ag(I) salts in a benzene/methylene chloride mixed solvent system. In addition, the luminescent
and electrical conductive properties of these new compounds were investigated.
Introduction
as N atoms) and metal-carbon or metal-π interactions could
be considered as the two most important interactions in the
The use of soluble inorganic transition metal salts or
unsaturated transition metal coordination complexes in
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as precursors to organic-inorganic coordination polymers
or supramolecular complexes is a rapidly growing area of
interest.1 These materials not only exhibit encouraging
potential applications2,3 but also generate new insights into
structural diversity. In this context, metal-heteroatoms (such
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* To whom correspondence should be addressed. E-mail: yubindong@
sdnu.edu.cn.
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10.1021/ic0508223 CCC: $30.25
Published on Web 08/20/2005
© 2005 American Chemical Society
Inorganic Chemistry, Vol. 44, No. 19, 2005 6591

Dong et al.
Chart 1. New and Known Five-Membered Heterocyclic Bridged Ligands Used by Us in Construction of Coordination Polymers
construction of polymeric architectures. Rigid and flexible
organic bidentate and multidentate ligands with terminal
N-donors as coordination sites separated by various spacers
have been used in recent years and have resulted in a number
of inorganic coordination polymers exhibiting a rich variety
of structural motifs.1 At the same time, smaller aromatic and
polycyclic aromatic hydrocarbons (PAHs), acting as electron-
donor species, were shown to be capable of incorporating
metal ions into organometallic polymeric systems through
cation-π interactions, as was previously demonstrated well
by many previous studies.4 In contrast, the chemistry of
polymeric compounds generated from multidenate organic
ligands that can afford both heteroatoms and carbon atoms
as coordination sites has received considerably less atten-
tion.5,6
bridging bent organic ligands with pyridyl-, cyano-, and
aminophenyl groups as the terminal coordination sites (Chart
1). As a result of the specific geometry of these five-
membered heterocyclic bridging ligands and of the coordina-
tion preferences of transition metals, various new coordina-
tion polymers have been obtained, some with open channels
and interesting luminescent properties.7 As we know, bent
rigid ligands do not propagate the metal coordination code
legibly into metal-organic architectures, which will make
it somewhat more difficult to forecast the coordination
network topologies.
(6) Recently we designed and synthesized a series of symmetric and
unsymmetric fulvene ligands which can coordinate metal ions with
both heteroatoms and π-donors as coordination sites; see the follow-
ing: (a) Dong, Y.-B.; Jin, G.-X.; Smith, M. D.; Huang, R.-Q.; Tong,
B.; zur Loye, H.-C. Inorg. Chem. 2002, 41, 4909. (b) Dong, Y.-B.;
Ma, J.-P.; Jin, G.-X.; Huang, R.-Q.; Smith, M. D. Dalton Trans. 2003,
22, 4324. (c) Dong, Y.-B.; Zhao, X.; Jin, G.-X.; Huang, R.-Q.; Smith,
M. D. Eur. J. Inorg. Chem. 2003, 22, 4017. (d) Dong, Y.-B.; Jin,
G.-X.; Zhao, X.; Huang, R.-Q.; Smith, M. D.; Stitzer, K. E.; zur Loye,
H.-C. Organometallics 2004, 23, 1604. (e) Dong, Y.-B.; Wang, P.;
Huang, R.-Q.; Smith, M. D. Inorg. Chem. 2004, 43, 4727. (f) Wang,
P.; Dong, Y.-B.; Huang, R.-Q.; Smith, M. D. Cryst. Growth Des. 2005,
5, 701. (g) Dong, Y.-B.; Geng, Y.; Ma, J.-P.; Huang, R.-Q. Inorg.
Chem. 2005, 44, 1693.
Recently, we have design and synthesized a series of five-
membered oxadiazole and triazole heteroatom cyclic rings
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6592 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
The carbon-carbon triple bond is classical organometallic
coordinating group with a rich diversity of modes of metal-
carbon bonding.8 So far, a number of novel binuclear,
multinuclear, polymeric, and catenane-like Au(I) and Cu(I)
complexes based on substituted ethynyl anion ligands have
been reported.9 In contrast, silver(I) acetylide compounds
based on silver-ethynyl (HCtC-) and silver-ethynediyl
(-CtC-) binding are less studied.9a,b This is probably due
to their instabilities with regard to light-induced decomposi-
tion reactions. To our knowledge, the coordination chemistry
based on bridged organic ligands with a neutral π-ethynyl
terminal group is still an undeveloped field. The idea herein
is to combine a five-membered oxadiazole ring with sub-
stituted -CtCH as a terminal coordination moiety to
generate new types of bent ligands by a Pd-catalyzed
coupling reaction (Scheme 1).10 It is expected that the
polymeric complexes based on such kinds of ligands could
be driven by both metal-heteroatom and metal-carbon or
metal-π coordination interactions. On the other hand, the
coordination orientation of π-donors on this type of ligands
is distinctly different from the known five-membered bridged
organic spacers (Chart 1), which would bring on the
coordination polymeric complexes with new patterns.
In this paper we wish to report on the synthesis of new
ligands L9 and L10 and a series of new Ag(I)-containing
organometallic polymeric complexes [Ag2(L9)](SO3CF3)2
(1), [Ag(L9)]ClO4 (2), [Ag(L9)]SbF6 (3), [Ag(L9)]BF4 (4),
[Ag(L10)]SO3CF3 (5), [Ag(L10)(H2O)0.5]BF4‚0.5H2O (6),
and {[Ag2(L10)2(H2O)](ClO4)2}‚o-xylene (7) based on both
metal-π and metal-nitrogen coordination interactions.
Experimental Section
Materials and Methods. AgSO3CF3, AgClO4, AgBF4, and
AgSbF6 (Acros) were used as obtained without further purification.
Infrared (IR) samples were prepared as KBr pellets, and spectra
were obtained in the 400-4000 cm-1 range using a Perkin-Elmer
1600 FTIR spectrometer. Elemental analyses were performed on a
1
Perkin-Elmer model 2400 analyzer. H NMR data were collected
using an AM-300 spectrometer. Chemical shifts are reported in δ
relative to TMS. All fluorescence measurements were carried out
on a Cary Eclipse spectrofluorometer (Varian, Australia) equipped
with a xenon lamp and quartz carrier at room temperature.
Thermogravimetric analyses were carried out using a TA Instrument
SDT 2960 simultaneous DTA-TGA under flowing nitrogen at a
heating rate of 10 °C/min. Electrical conductivity was performed
on Agilent Technologies (4294A-ATO-20150). XRD pattern were
obtained on a D8 ADVANCE X-ray powder diffraction (XRD) with
Cu KR radiation (λ ) 1.5405 Å).
Caution! Two of the crystallization procedures involve AgClO4,
which is a strong oxidizer.
(7) (a) Dong, Y.-B.; Ma, J.-P.; Smith, M. D.; Huang, R.-Q.; Tang, B.;
Chen, D.; zur Loye, H.-C. Solid State Sci. 2002, 4, 1313. (b) Dong,
Y.-B.; Ma, J.-P.; Huang, R.-Q.; Smith, M. D.; zur Loye, H.-C. Inorg.
Chem. 2003, 42, 294. (c) Dong, Y.-B.; Ma, J.-P.; Smith, M. D.; Huang,
R.-Q.; Tang, B.; Guo, D.-S.; Wang, J.-S.; zur Loye, H.-C. Solid State
Sci. 2003, 5, 601. (d) Dong, Y.-B.; Ma, J.-P.; Smith, M. D.; Huang,
R.-Q.; Wang, J.-S.; zur Loye, H.-C. Solid State Sci. 2003, 5, 1177.
(e) Dong, Y.-B.; Cheng, J.-Y.; Wang, H.-Y.; Huang, R.-Q.; Tang, B.;
Smith, M. D.; zur Loye, H.-C. Chem. Mater. 2003, 15, 2593. (f) Dong,
Y.-B.; Ma, J.-P.; Huang, R.-Q.; Liang, F.-Z.; Smith, M. D. Dalton
Trans. 2003, 9, 1472. (g) Dong, Y.-B.; Cheng, J.-Y.; Huang, R.-Q.;
Tang, B.; Smith, M. D.; zur Loye, H.-C. Inorg. Chem. 2003, 42, 5699.
(h) Cheng, J.-Y.; Dong, Y.-B.; Ma, J.-P.; Huang, R.-Q.; Smith, M. D.
Inorg. Chem. Commun. 2005, 8, 6. (i) Dong, Y.-B.; Cheng, J.-Y.;
Huang, R.-Q.; Smith, M. D. Inorg. Chim. Acta 2005, 358, 891. (j)
Dong, Y.-B.; Cheng, J.-Y.; Ma, J.-P.; Huang R.-Q.; Smith, M. D. Cryst.
Growth Des. 2005, 5, 585. (k) Dong, Y.-B.; Wang, H.-Y.; Ma, J.-P.;
Huang, R.-Q.; Smith, M. D. Cryst. Growth Des. 2005, 5, 789. (l) Wang,
P.; Dong, Y.-B.; Ma, J.-P.; Huang, R.-Q.; Smith, M. D. Inorg. Chem.
Commun. 2005, 8, 596. (m) Dong, Y.-B.; Wang, H.-Y.; Ma, J.-P.;
Shen, D.-Z.; Huang, R.-Q. Inorg. Chem. 2005, 44, 4679. (n) Ma, J.
P.; Dong, Y.-B.; Huang, R.-Q.; Smith, M. D.; Cheng, Y. S. Inorg
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Preparation of L9. To a solution of S1 (2.50 g, 5.27 mmol)
and HCtCSiMe3 (1.65 mL, 12 mmol) in triethylamine (100 mL)
were added Pd(PPh3)Cl2 (89.5 mg, 0.58 mmol) and CuI (72.7 mg,
0.26 mmol). The mixture was stirred overnight at room temperature.
After removal the solvent under vacuum, the residue was purified
on silica gel by column using CH2Cl2 as the eluent to give 2,5-
bis(4-((trimethylsilyl)ethynyl)phenyl)-1,3,4-oxadiazole as a white
solid (yield 97%). The white solid obtained was added to a methanol
solution of potassium hydroxide. The mixture was stirred for 24 h
at room temperature. After the hydrolysis was complete (monitored
by TLC), the solvent was removed under vacuum and the residue
was purified by chromatograpy on silica gel using methylene
chloride as the eluent to afford a light yellow solid. Yield: 1.29 g,
1
90%. Mp: 210-211 °C. H NMR (300 MHz, DMSO-d6, 25 °C,
TMS, ppm): 8.10 (d, 4H, -C6H4), 7.68 (d, 4H, -C6H4), 4.46 (s,
2H, -CtCH). IR (KBr, cm-1): 3286 (s), 2170 (w), 1933 (s), 1609
(w), 1572 (m), 1483 (s), 1263 (m), 1099 (s), 1076 (m), 848 (s),
747 (s), 708 (s), 679 (s), 620 (s), 537 (m). Anal. Calcd for
C18H10N2O (L9): C, 80.00; H, 3.70; N, 10.37. Found: C, 79.79;
H, 3.80; N, 10.34. UV-vis spectrum (in CH3CN at room temper-
ature): λmax ) 308 nm.
Preparation of L10. To a solution of S2 (1.42 g, 3.0 mmol)
and HCtCC(Me)2OH (0.64 mL, 6.6 mmol) in triethylamine (30
mL) were added THF (8 mL), Pd(PPh3)Cl2 (46.0 mg, 0.066 mmol),
and CuI (38.0 mg, 0.20 mmol). The mixture was stirred overnight
at room temperature. After removal of the solvent under vacuum,
the residue was purified on silica gel by column using CH2Cl2/
CH3CO2Et (2:1, v/v) as the eluent to give 2,5-bis[4-(2′-methyl-3′-
butyn-2′-olphenyl)]-1,3,4-oxadiazole as a white solid (yield 95%).
The white solid obtained was added to a benzene solution of sodium
hydroxide. The mixture was refluxed for 2 h. After the hydrolysis
was complete (monitored by TLC), the solvent was removed under
vacuum and the residue was purified by chromatograpy on silica
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Inorganic Chemistry, Vol. 44, No. 19, 2005 6593

Dong et al.
Scheme 1. Synthesis of New Ligands L9 and L10 and Compounds 1-7
gel using methylene chloride as the eluent to afford a light yellow
solid. Yield: 0.66 g, 85%. Mp: 180-182 °C. 1H NMR (300 MHz,
DMSO-d6, 25 °C, TMS, ppm): 8.25 (s, 2H, -C6H4), 8.20 (d, 2H,
-C6H4), 7.75 (d, 2H, -C6H4), 7.65 (t, 2H, -C6H4), 4.41 (s, 2H,
-CtCH). IR (KBr, cm-1): 3277 (s), 2169 (w), 1638 (s), 1618
(s), 1541 (m), 1401 (s), 902 (w), 840 (w), 807 (w), 734 (w), 670
(w), 620 (m), 478 (m). Anal. Calcd for C18H10N2O (L10): C, 80.00;
H, 3.70; N, 10.37. Found: C, 79.87; H, 3.39; N, 10.16. UV-vis
spectrum (in CH3CN at room temperature): λmax ) 278 nm.
Preparation of [Ag2(L9)](SO3CF3)2 (1). A solution of AgSO3CF3
(25.6 mg, 0.10 mmol) in benzene (8 mL) was layered onto a
solution of L9 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL). The
sloutions were left for about 2 days at room temperature, and
colorless crystals were obtained. Yield: 87%. IR (KBr, cm-1): 3288
(s), 2170 (w), 2111 (w), 1608 (s), 1574 (s), 1548 (s), 1490 (s),
1403 (s), 1281 (vs), 1244 (s), 1179 (s), 1022 (s), 846 (s), 746 (s),
30.61; H, 1.28; N, 3.57. Found: C, 30.52; H, 1.21; N, 3.23. UV-
vis spectrum (in CH3CN at room temperature): λmax ) 308 nm.
Preparation of [Ag(L9)]ClO4 (2). A solution of AgClO4 (20.7
mg, 0.10 mmol) in benzene (8 mL) was layered onto a solution of
L9 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL). The sloutions were
left for about 2 days at room temperature, and colorless crystals
were obtained. Yield: 86%. IR (KBr, cm-1): 3287 (s), 2170 (w),
2105(w), 1608 (s), 1546 (s), 1488 (s), 1404 (s), 1264 (vs), 1022
(s), 846 (s), 746 (s), 625 (s), 577 (m), 517 (s). 1H NMR (300 MHz,
DMSO-d6, 25 °C, TMS, ppm): 8.13 (d, 4H, -C6H4), 7.72 (d, 4H,
-C6H4), 4.48 (s, 2H, -CtCH). Anal. Calcd for C18H10AgClN2O5:
C, 45.28; H, 2.10; N, 5.87. Found: C, 45.22; H, 2.00; N, 5.61.
UV-vis spectrum (in CH3CN at room temperature): λmax ) 302
nm.
Preparation of [Ag(L9)]SbF6 (3). A solution of AgSbF6 (34.4
mg, 0.10 mmol) in benzene (8 mL) was layered onto a solution of
L9 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL). The sloutions were
left for about 2 days at room temperature, and colorless crystals
were obtained. Yield: 86%. IR (KBr, cm-1): 3286 (m), 2078 (w),
1
706 (m), 628 (s), 536 (m), 515 (m). HNMR (300 MHz, DMSO-
d6, 25 °C, TMS, ppm): 8.13 (d, 4H, -C6H4), 7.70 (d, 4H, -C6H4),
4.47 (s, 2H, -CtCH). Anal. Calcd for C24H10Ag2F6N2O7S2: C,
6594 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Table 1. Crystallographic Data for L10 and 1-3a
param
L10
1
2
3
empirical formula
fw
C18H10N2O
270.28
C20H10Ag2F6N2O7S2
784.16
C18H10AgF6N2OSb
613.90
C18H10AgBF4N2O
464.96
cryst syst
a (Å)
b (Å)
c (Å)
a (deg)
b (deg)
g (deg)
V (Å3)
monoclinic
31.405(7)
6.2903(14)
15.406(3)
90
118.656(3)
90
2670.6(10)
C2/c
triclinic
orthorhombic
19.059(9)
12.922(6)
15.609(7)
90
90
90
3844(3)
Cmca
8
orthorhombic
19.128(3)
12.6042(18)
28.003(4)
90
10.292(4)
10.794(4)
11.399(5)
98.894(5)
102.360(6)
90.319(5)
1221.2(8)
P1h
90
90
6751.5(16)
Cmca
16
1.830
1.246
space group
Z value
8
2
F
calcd (g/cm3)
1.344
0.085
293(2)
2.133
1.866
293(2)
2.121
2.492
293(2)
µ(Mo KR) (mm-1
)
temp (K)
293(2)
no. of observns (I > 3σ(Ι))
final R indices [I > 2σ(I)]: R; Rw
2482
0.0457; 0.1133
4424
0.0559; 0.1513
1847
0.0738; 0.1736
3238
0.0683; 0.1764
a R1 ) Σ||Fo| - |Fc||/Σ|Fo|. wR2 ) {Σ[w(Fo - Fc )2]/Σ[w(Fo )2]}1/2
.
2
2
2
1609 (m), 1545 (m), 1488 (s), 1402 (s), 1261 (vs), 1026 (s), 846
(s), 746 (s), 648 (s), 624 (s), 578 (w), 517 (m). 1H NMR (300 MHz,
DMSO-d6, 25 °C, TMS, ppm): 8.12 (d, 4H, -C6H4), 7.69 (d, 4H,
-C6H4), 4.47 (s, 2H, -CtCH). Anal. Calcd for C18H10AgF6N2-
OSb: C, 35.20; H, 1.63; N, 4.56. Found: C, 35.52; H, 1.41; N,
AgBF4N2O2: C, 44.72; H, 2.48; N, 5.80. Found: C, 44.24; H, 2.59;
N, 5.55. UV-vis spectrum (in CH3CN at room temperature): λmax
) 284 nm.
Preparation of {[Ag2(L10)2(H2O)](ClO4)2}‚o-xylene (7). A
solution of AgClO4 (20.7 mg, 0.10 mmol) in benzene (8 mL) was
layered onto a solution of L10 (27.0 mg, 0.10 mmol) in CH2Cl2 (8
mL). The sloutions were left for 3 days at room temperature, and
colorless crystals were obtained. Yield: 85%. IR (KBr, cm-1): 3257
(s), 2169 (w), 2109 (w), 1639 (s), 1617 (s), 1549 (m), 1401 (s),
1111 (s), 890 (w), 841(w), 806 (w), 738 (m), 679 (w), 620 (s), 473
(w). 1H NMR (300 MHz, DMSO-d6, 25 °C, TMS, ppm): 8.24 (s,
2H, -C6H4), 8.19 (d, 2H, -C6H4), 7.74 (d, 2H, -C6H4), 7.64 (t,
2H, -C6H4), 7.02-7.18 (m, 4H, -C6H4), 4.41 (s, 2H, -CtCH),
2.19 (s, 6H, -CH3). Anal. Calcd for C26H22Ag2Cl2N2O10: C, 26.70;
H, 1.48; N, 3.46. Found: C, 27.15; H, 1.23; N, 3.26. UV-vis
spectrum (in CH3CN at room temperature): λmax ) 282 nm.
Single-Crystal Structure Determination. Suitable single crys-
tals of 1-7 were selected and mounted in air onto thin glass fibers.
X-ray intensity data were measured at 150 K on a Bruker SMART
APEX CCD-based diffractometer (Mo KR radiation, λ ) 0.710 73
Å). The raw frame data for 1-7 were integrated into SHELX-format
reflection files and corrected for Lorentz and polarization effects
using SAINT.11 Corrections for incident and diffracted beam
absorption effects were applied using SADABS.11 None of the
crystals showed evidence of crystal decay during data collection.
All structures were solved by a combination of direct methods and
difference Fourier syntheses and refined against F2 by the full-
matrix least-squares technique. Crystal data, data collection pa-
rameters, and refinement statistics for 1-7 are listed in Tables 1
and 2. Relevant interatomic bond distances and bond angles for
1-7 are given in Tables 3-9.
4.43. UV-vis spectrum (in CH3CN at room temperature): λmax
)
304 nm.
Preparation of [Ag(L9)]BF4 (4). A solution of AgBF4 (19.5
mg, 0.10 mmol) in benzene (8 mL) was layered onto a solution of
L9 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL). The sloutions were
left for about 2 days at room temperature, and colorless crystals
were obtained. Yield: 87%. IR (KBr, cm-1): 3288 (vs), 2072 (w),
1638 (w), 1619 (w), 1573 (w), 1545 (s), 1486(m), 1400 (s), 1265
(m), 1100 (s), 847(s), 747 (s), 707 (m), 677 (m), 654 (s), 621 (s),
536 (s). 1H NMR (300 MHz, DMSO-d6, 25 °C, TMS, ppm): 8.13
(d, 4H, -C6H4), 7.72 (d, 4H, -C6H4), 4.48 (s, 2H, -CtCH). Anal.
Calcd for C18H10AgBF4N2O: C, 46.45; H, 2.15; N, 6.02. Found:
C, 46.75; H, 2.45; N, 6.33. UV-vis spectrum (in CH3CN at room
temperature): λmax ) 308 nm.
Preparation of [Ag(L10)]SO3CF3 (5). A solution of AgSO3-
CF3(25.6 mg, 0.10 mmol) in benzene (8 mL) was layered onto a
solution of L10 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL). The
sloutions were left for about 3 days at room temperature, and
colorless crystals were obtained. Yield: 86%. IR (KBr, cm-1): 3253
(s), 2170 (w), 2098 (w), 1638 (s), 1620 (s), 1542 (s), 1402 (s),
1264 (s), 1158 (s), 1086 (m), 1029 (s), 902 (m), 822 (m), 802 (m),
1
737 (m), 682 (m), 626 (s), 513 (m). H NMR (300 MHz, DMSO-
d6, 25 °C, TMS, ppm): 8.24 (s, 2H, -C6H4), 8.18 (d, 2H, -C6H4),
7.74 (d, 2H, -C6H4), 7.64 (t, 2H, -C6H4), 4.40 (s, 2H, -CtCH).
Anal. Calcd for C19H10Ag F3N2O4S: C, 40.99; H, 1.90; N, 5.31.
Found: C, 41.34; H, 1.59; N, 5.12. UV-vis spectrum (in CH3CN
at room temperature): λmax ) 280 nm.
Results and Discussion
Preparation of [Ag(L10)(H2O)0.5]BF4‚0.5H2O (6). A solution
of AgBF4 (19.5 mg, 0.10 mmol) in benzene (8 mL) was layered
onto a solution of L10 (27.0 mg, 0.10 mmol) in CH2Cl2 (8 mL).
The sloutions were left for 1 day at room temperature, and colorless
crystals were obtained. Yield: 85%. IR (KBr, cm-1): 3276 (s),
2169 (w), 2107(w), 1638 (s), 1618 (s), 1544 (m), 1401 (s), 1084
(s), 913 (w), 842 (w), 805 (w), 737 (w), 682 (m), 624 (m), 478
(w). 1H NMR (300 MHz, DMSO-d6, 25 °C, TMS, ppm): 8.25 (s,
2H, -C6H4), 8.20 (d, 2H, -C6H4), 7.76 (d, 2H, -C6H4), 7.65 (t,
2H, -C6H4), 4.41 (s, 2H, -CtCH). Anal. Calcd for C18H12-
Synthesis and Structural Analysis of Ligands L9 and
L10. L9 and L10 were synthesized by a Pd-catalyzed
reaction. They can be considered as new members of the
bent five-membered heterocyclic ring-bridging organic ligands.
Their structures have been fully characterized by infrared
1
spectroscopy, elemental analysis, and H NMR. To further
confirm the structure of the new ligands, the solid molecular
(11) Bruker Analytical X-ray Systems, Inc., Madison, WI, 1998.
Inorganic Chemistry, Vol. 44, No. 19, 2005 6595

Dong et al.
Table 2. Crystallographic Data for 4-7a
param
4
5
6
7
empirical formula
fw
cryst syst
a (Å)
b (Å)
c (Å)
C18H10AgClN2O5
477.60
C19H10AgF3N2O4S
527.22
triclinic
C18H12AgBF4N2O2
482.98
C44H32Ag2Cl2N4O11
1079.38
monoclinic
8.1460(10)
17.326(2)
30.345(4)
90
97.71
90
4244.0(9)
P21/c
2
1.689
1.116
293(2)
8288
0.0393; 0.1078
monoclinic
8.5153(16)
19.722(4)
10.320(2)
90
105.307(3)
90
999.97(19)
P1h
4
monoclinic
32.180(6)
17.027(3)
8.1453(15)
90
102.541(3)
90
4356.7(14)
C2/m
9.0605(13)
10.4956(15)
10.8085(16)
101.666(2)
109.269(2)
100.944(2)
912.9(2)
P1h
a (deg)
b (deg)
g (deg)
V (Å3)
space group
Z value
2
4
F
calcd (g/cm3)
1.898
1.401
293(2)
2939
1.918
1.280
293(2)
3221
1.473
0.972
293(2)
4141
µ(Mo KR) (mm-1
)
temp (K)
no. of observns (I > 3σ(Ι))
final R indices [I > 2σ(I)]: R; Rw
0.0728; 0.1458
0.0284; 0.0755
0.0720; 0.1718
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) {∑[w(Fo - Fc )2]/∑[w(Fo )2]}1/2
.
2
2
2
Table 3. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 1a
Table 6. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 4a
Ag(1)-N(2)
Ag(1)-O(2)
Ag(1)-C(5)#2
Ag(2)-O(4)#3
Ag(2)-O(7)
2.369(5)
2.464(6)
2.532(8)
2.303(6)
2.640(5)
Ag(1)-O(6)#1
Ag(1)-O(7)
Ag(2)-N(1)
Ag(2)-O(4)
2.375(6)
2.525(5)
2.200(5)
2.509(6)
Ag(1)-N(1)#1
Ag(1)-C(5)#2
2.257(5)
2.473(8)
Ag(1)-N(2)
Ag(1)-O(2)
2.295(5)
2.597(6)
N(1)#1-Ag(1) -N(2) 125.54(18) N(1)#1-Ag(1)-C(5)#2 123.5(3)
N(2)-Ag(1)-C(5)#2
N(2)-Ag(1)-O(2)
89.4(3)
104.9(2)
N(1)#1-Ag(1)-O(2)
C(5)#2-Ag(1)-O(2)
108.4(2)
101.3(3)
N(2)-Ag(1)-O(6)#1 127.5(2)
O(6)#1-Ag(1) -O(2) 86.9(2)
O(6)#1-Ag(1)-O(7) 126.6(2)
N(2)-Ag(1)-C(5)#2 104.9(2)
O(2)-Ag(1)-C(5)#2 157.6(3)
N(1)-Ag(2)-O(4)#3 157.8(2)
N(2)-Ag(1)-O(2)
N(2)-Ag(1)-O(7)
O(2)-Ag(1)-O(7)
96.5(2)
105.32(18)
79.3(2)
a Symmetry transformations used to generate equivalent atoms: (#1) -x
+ 1, -y + 1, -z + 1; (#2) x - 1, y, z - 1; (#3) x + 1, y, z + 1.
O(6)#1-Ag(1)-C(5)#2 85.4(3)
Table 7. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 5a
O(7)-Ag(1)-C(5)#2
N(1)-Ag(2)-O(4)
89.37(18) N(1)-Ag(2)-O(7)
81.46(19) O(4)-Ag(2)-O(7)
88.5(2)
112.68(19)
104.00(18)
80.69(18)
O(4)#3-Ag(2)-O(4)
O(4)#3-Ag(2)-O(7)
Ag(1)-N(1)#1
Ag(1)-O(3)#2
N(1)-C(9)
2.3123(19)
2.502(2)
1.291(3)
Ag(1)-N(2)
Ag(1)-O(2)
N(1)-Ag(1)#1
2.334(2)
2.705(3)
2.3123(19)
a Symmetry transformations used to generate equivalent atoms: (#1) -x
+ 1,-y + 1,-z; (#2) -x, -y + 2, -z; (#3) -x, -y + 1, -z.
N(1)#1-Ag(1)-N(2) 128.95(7) N(1)#1-Ag(1)-O(3)#2 115.05(7)
N(2)-Ag(1)-O(3)#2 115.67(7) N(1)#1-Ag(1)-O(2)
N(2)-Ag(1)-O(2) 113.58(7) O(3)#2-Ag(1)-O(2)
81.35(7)
79.09(7)
Table 4. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 2a
a Symmetry transformations used to generate equivalent atoms: (#1) -x
+ 1, -y + 1, -z; (#2) -x + 2, -y + 1, -z.
Ag(1)-N(1)
2.281(7)
Ag(1)-C(7)#2
2.555(14)
N(1)-Ag(1)-N(1)#1
120.6(3) N(1)-Ag(1)-C(7)#2
89.5(3) N(1)-Ag(1)-C(7)#3
101.6(3)
89.5(3)
Table 8. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 6a
N(1)#1-Ag(1)-C(7)#2
N(1)#1-Ag(1)-C(7)#3 101.6(3) C(7)#2-Ag(1)-C(7)#3 157.6(5)
C(1)-N(1)-N(1)#4
106.3(5) C(1)-N(1)-Ag(1)
132.8(6)
Ag(1)-C(6)#1
Ag(1)-N(2)
Ag(1)-O(3)
2.287(8)
2.303(5)
2.515(5)
Ag(1)-N(1)
Ag(1)-C(5)#1
2.301(5)
2.411(7)
a Symmetry transformations used to generate equivalent atoms: (#1) x,
-y, -z; (#2) -x + 3/2, -y + 1/2, -z; (#3) -x + 3/2, y - 1/2, z; (#4) -x
+ 2, y, z; (#5) -x, y, z.
C(6)#1-Ag(1)-N(1) 145.9(3)
C(6)#1-Ag(1)-N(2)
113.3(3)
N(1)-Ag(1)-N(2)
95.62(18) C(6)#1-Ag(1)-C(5)#1
29.6(2)
141.3(2)
84.0(2)
Table 5. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 3a
N(1)-Ag(1)-C(5)#1 117.3(2)
C(6)#1-Ag(1)-O(3) 113.1(3)
N(2)-Ag(1)-C(5)#1
N(1)-Ag(1)-O(3)
N(2)-Ag(1)-O(3)
88.49(19) C(5)#1-Ag(1)-O(3)
113.4(2)
Ag(1)-N(1)
Ag(1)-C(7)#1
Ag(1)-C(6)#1
2.316(5)
2.434(8)
2.671(6)
Ag(1)-N(2)
Ag(1)-C(16)#2
2.329(5)
2.442(7)
a Symmetry transformations used to generate equivalent atoms: (#1) -x
+ 1/2, -y + 3/2, -z; (#2) x, -y + 1, z; (#3) -x, y, -z.
N(1)-Ag(1)-N(2)
121.69(17) N(1)-Ag(1)-C(7)#1
91.9(2)
100.3(2)
C(7)#1-Ag(1)-C(16)#2 157.2(3)
N(2)-Ag(1)-C(6)#1 101.4(2)
C(16)#2-Ag(1)-C(6)#1 132.1(2)
N(2)-Ag(1)-C(7)#1
N(2)-Ag(1)-C(16)#2
N(1)-Ag(1)-C(6)#1
101.0(3)
88.9(2)
112.6(2)
N(1)-Ag(1)-C(16)#2
oxadiazole moiety basically lie in the same plane and are
linked together at the meta position by the five-membered
oxadiazole ring. L9 and L10 are soluble in common organic
solvents such as CH2Cl2, CHCl3, THF, CH3OH, and C2H5OH,
which facilitates the solution reaction between the ligands
and inorganic metal salts. It is worthy pointing out that the
coordination orientations of the terminal π-donors in L9 and
L10 are different from that of heteratom donors in L1-L8
(Scheme 1), which will results in the patterns of the
coordination polymers based on L9 and L10 not easy
C(7)#1-Ag(1)-C(6)#1 26.0(2)
a Symmetry transformations used to generate equivalent atoms: (#1) -x
+ 1/2, y + 1/2, z; (#2) -x + 1/2, y - 1/2, z. #3 -x+1,y,z #4 -x+2,y,z
structure of L10 was determined using single-crystal X-ray
diffraction. As shown in Figure 1, the shape of the ligand is
bent, which is similar to the known organic ligands of L1-
L8. Two terminal benzoacetylene groups and a bridging
6596 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Table 9. Interatomic Distances (Å) and Bond Angles (deg) with Esd’s
in Parentheses for 7a
Ag(1)-C(33)#1
Ag(1)-N(1)
Ag(1)-O(3)
Ag(2)-C(26)#2
Ag(2)-C(25)#2
2.324(3)
2.335(3)
2.519(3)
2.288(4)
2.451(3)
Ag(1)-N(3)
Ag(1)-C(32)#1
Ag(2)-N(4)
Ag(2)-N(2)
Ag(2)-O(3)
2.328(3)
2.443(3)
2.277(3)
2.327(3)
2.523(3)
C(33)#1-Ag(1)-N(3)
N(3)-Ag(1)-N(1)
N(3)-Ag(1)-C(32)#1
C(33)#1-Ag(1)-O(3)
N(1)-Ag(1)-O(3)
N(4)-Ag(2)-C(26)#2
C(26)#2-Ag( 2)-N(2)
C(26)#2-Ag(2)-C(25)#2 29.11(12) N(2)-Ag(2)-C(25)#2
141.54(11) C(33)#1-Ag(1)-N(1)
92.25(9) C(33)#1-Ag(1)-C(32)#1 28.71(12)
114.40(10) N(1)-Ag(1)-C(32)#1
118.09(12) N(3)-Ag(1)-O(3)
86.25(9) C(32)#1-Ag(1)-O(3)
149.79(12) N(4)-Ag(2)-N(2)
113.23(12) N(4)-Ag(2)-C(25)#2
117.64(11)
143.94(11)
85.42(9)
118.20(10)
93.01(9)
120.84(10)
138.92(11)
109.15(13)
116.11(11)
N(4)-Ag(2)-O(3)
N(2)-Ag(2)-O(3)
86.34(9) C(26)#2-Ag( 2)-O(3)
86.25(9) C(25)#2-Ag(2)-O(3)
a Symmetry transformations used to generate equivalent atoms: (#1) -x,
y + 1/2, -z + 1/2; (#2) -x, y - 1/2, -z + 1/2.
Figure 2. ORTEP figure of 1 (50% probability ellipsoids). Only
coordinated oxygen atoms of triflate anions are shown.
Ag-O bond lengths range from 2.303 to 2.640 Å. Two Ag(I)
atoms (Ag(1) and Ag(2)) are bridged by two Noxadiazole atoms
and one triflate O-donor into a five-membered {Ag2N2O}
dinuclear core with a short Ag‚‚‚Ag contact of 3.45 Å. The
five-membered {Ag2N2O} dinuclear core is different from
the six-membered {Ag2N4} moiety commonly found in many
previous Ag(I)-coordination polymers based on L1-L8.8
In the solid state, Ag(I) atoms are bound to each other by
coordinated triflate counterions into inorganic Ag(I)-
-
Figure 1. Molecular structure of L10.
SO3CF3 chains along the crystallographic a axis. The
shortest intrachain Ag‚‚‚Ag distance is 3.42 Å, which is
achievable by the known bent organic spacers L1-L8. In
addition, new ligands L9 and L10 give us a chance to modify
them to new longer organic spacers with different coordina-
tion functional groups by some functional transform reactions
related to -CtCH, such as the well-known Heck-Cassar-
Sonogashira-Hagihara reaction.12
Structural Analysis. Structural Analysis of [Ag2(L9)]-
(SO3CF3)2 (1). Crystallization of L9 with AgSO3CF3 in a
CH2Cl2/C6H6 mixed solvent system at room temperature
afforded the infinite two-dimensional chain structure in 87%
yield. Single-crystal analysis revealed that there are two kinds
of crystallographic Ag(I) centers in 1. Compound 1 is air
stable. As shown in Figure 2, the first Ag(I) center lies in a
{AgNO3π} coordination sphere, being made of one Noxadiazole
donor (N(2), dAg(1)-N(2) ) 2.369(5) Å) and three O donors
slightly shorter than the sum of the van der Waals radii of
-
two silver atoms, 3.44 Å (Figure 3).13 These Ag(I)-SO3CF3
inorganic chains are separated by organic layers consisting
of the L9 ligands and, moreover, bound to the Ag(I)-
SO3CF3- inorganic chains by Ag-N and Ag-π interactions
into a two-dimensional network. As shown in Figure 4, the
organic and inorganic layers are arranged alternatively along
the crystallographic b axis in this two-dimensional net.
Structural Analysis of [Ag(L9)]ClO4 (2). The L9 ligand
reacted with AgClO4 in CH2Cl2/C6H6 at room temperature
to produce the polymeric compound 2 as colorless crystals
with novel one-dimensional network in 86% yield. Com-
pound 2 is air stable. The structure of complex 2, emphasiz-
ing the environment around the silver, is shown in Figure 5.
Each Ag(I) center lies in a distorted tetrahedral coordination
environment {AgN2Oπ} consisting of two oxadiazole N
donors from two L9 ligands (Ag(1)-N(1) ) 2.257(5) and
(O(2), O(6), and O(7), dAg(1)-O(2) ) 2.464(6), dAg(1)-O(6)
)
2.375(6), and dAg(1)-O(7) ) 2.525(5) Å) from one L9 ligand
and two coordinated SO3CF3- counterions and one π-donor
(Ag(1)-C bond distances range from 2.532(5) to 2.753(5)
Å) from the coordinated η2-CtCH group on the other L9
ligand, respectively. It is worthwhile to point out that only
one terminal -CtCH group on L9 involves the Ag(I)
coordination sphere. Thus, the ligand L9 herein acts as a
tridentate ligand toward the Ag(I) ion. The second Ag(I)
center adopts a {AgNO4} coordination sphere, consisting of
one Noxadiazole donor (N(1), dAg(2)-N(1) ) 2.200(5) Å) and four
-
Ag(1)-N(2) ) 2.295(5) Å), one coordinated ClO4 anion
(Ag(1)-O(2) ) 2.597(6) Å), and one terminal η2-CtCH
group (Ag(1)-C(5) ) 2.473(8) and Ag(1)-C(4) ) 2.768(8)
Å). It is similar to compound 1; only one -CtCH group in
2 is coordinated to the silver center, and the Ag-π bonds
serve as the interaction to link {Ag2(L9)2} building blocks
to form a one-dimensional polymeric chain along the
crystallographic [101] direction (Figure 6).
As noted above, in complexes 1 and 2, only one of two
acetylene moieties of L9 involves in the silver coordination
Otriflate donors from two coordinated triflate counterions. The
(12) (a) Dieck, H. A.; Heck, R. F. J. Org. Chem. 1975, 40, 259. (b) Cassar,
I. J. Org. Chem. 1975, 40, 253. (c) Sonogashira, K.; Tohda, Y.;
Hagihara, N. Tetrahedron Lett. 1975, 16, 4467.
(13) (a) Slater, J. C. J. Chem. Phys. 1964, 41, 3199. (b) Emsley, J. The
Elements; Clarendon: Oxford, U.K., 1989; p 192.
Inorganic Chemistry, Vol. 44, No. 19, 2005 6597

Dong et al.
-
Figure 3. Ag(I)-SO3CF3 chain extended along the crystallographic a axis. The Ag‚‚‚Ag interactions are shown as dotted lines.
Figure 4. Crystal packing of 1.
two η2-CtCH groups all involve the Ag(I) coordination
sphere. The corresponding Ag(I)-Noxadiazole and
Ag(I)-C bonding distances are 2.281(7) and 2.555(14)
Å, respectively. The Ag(I) and L9 connectivity has the
{Ag2N4} groupings, which is different from the {Ag2N2O}
dinuclear core as observed in compound 1. The Ag‚‚‚Ag
distance in the {Ag2N4} moiety is 3.66 Å, which is slightly
longer than the sum of the van der Waals radii of two silver
atoms. It is different from 2; the {Ag2(L9)2} unit is
introduced into a two-dimensional net by the Ag-π inter-
actions (Figure 8) instead of a one-dimensional chain
observed in 2. This two-dimensional net is flat and contains
the rhombuslike binuclear metallacycles. The crystallographic
dimensions are 15 × 6 Å. In addition, these layers stack
together exactly along the crystallographic c axis, and the
uncoordinated SbF6- counterions are located between these
layers (Figure 9).
Figure 5. ORTEP figure of compound 2 (50% probability ellipsoids).
sphere and the other is free. However, it is worthy pointing
out that, in these specific reactions, the final products do
not depend on of the metal-to-ligand ratio. The different
metal-to-ligand ratios including 1:2 and even 1:3 were tried
in performing the reactions, and compounds 1 and 2 were
isolated as the only products. The probably reason is that
Combination of AgBF4 with L9 in a CH2Cl2/benzene
mixed-solvent system generates complex 4 at 87% yield.
Compound 4 and 3 are isostructural. 4 crystallizes in the
orthorhombic space group Cmca, which is the same as 3. In
4, the Ag(I) center lies in a distorted tetrahedral {AgN2π2}
coordination sphere which is analogous to that of 3 (Figure
10). In the solid state, compound 4 exhibits the same
noninterpenetrating two-dimensional network (Figure 11) as
-
-
the O donor on the coordinated SO3CF3 or ClO4 prefer-
entially involves the Ag(I) coordination sphere due to its
stronger coordination tendency toward a “soft” Ag(I) atom
than the weaker -CtC- π donor.
Structural Analysis of [Ag(L9)]SbF6 (3) and [Ag(L9)]-
BF4 (4). To investigate the effect of the counterion on the
long-range order of the Ag(I)-L9 coordination polymer, the
weaker coordinated SbF6- and BF4- anions were used instead
-
found in compound 3. Rhombuslike channels contain BF4
-
-
of the stronger coordination SO3CF3 and ClO4 anions.
counterions. The corresponding channel dimensions are
almost identical with those of 3.
Crystallization of L9 with AgSbF6 in a CH2Cl2/C6H6
mixed-solvent system at room temperature afforded the
infinite noninterpenetrating two-dimensional polymeric com-
pound 3 in 86% yield. Compound 3 is air stable. As shown
in Figure 7, there is only one type of crystallographic Ag(I)
center in 3. It adopts a distorted tetrahedral {AgN2π2}
coordination sphere that consists of two Noxadiazole and two
η2-CtCH groups from four L9 ligands, respectively. In 3,
L9 acts as a tetradentate ligand, in which two Noxadiazole and
The common feature of compounds 3 and 4 lies that both
terminal -CtCH groups on the L9 ligand coordinate to
Ag(I) centers through a Ag-π interaction, which is distinctly
different from the coordination behavior of L9 in 1 and 2.
The only possible explanation for this change might be the
coordination behaviors resulting from the different counter-
-
-
ions (from coordinated anions SO3CF3 and ClO4 to
-
-
uncoordinated SbF6 and BF4 ) due to all three reactions
6598 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
-
Figure 6. View of the one-dimensional chain architecture of 2. The coordinated ClO4 anions are omitted for clarity.
3,3′-bipyridine and 3,3′-biphenylamine ligands could bind
metal ions by cis or trans conformation and result in a
framework topology that is versatile, sometimes even in
affecting the formation of polymer vs molecule. The im-
mediate coordination arrangement around the silver center
in 5 is shown in Figure 12. Each silver center in 5 lies in a
distorted tetrahedral {AgN2Oπ} coordination sphere, with
two oxadiazole N donors from two L10 ligands, one O donor
-
from the one coordinated SO3CF3 counterion, and a pair
of π-electrons from the coordinated η1-CtCH group from
the third L10 ligand. The Ag-C(6) bond distance is
2.855(16) Å, while the Ag‚‚‚C(5) contact is 3.149(15) Å,
which is much longer than the normal Ag-C bond length
of 2.80 Å. The Ag-N bond distances are 2.3123(19) and
2.334(2) Å, respectively, which are comparable to the
corresponding bond lengths of 1-4. The Ag-O bond length
is 2.502(2) Å, which lies in the normal range of Ag-O bond
distance. Herein, only one of two terminal -CtCH groups
of L10 coordinates to the Ag(I) center, which is the same as
observed in compounds 1 and 2. Two Ag(I) atoms are
connected by two L10 ligands through the four oxadiazole
N donors to form an “X-shaped” building block, in which
two L10 ligands are exactly in the same plane. The Ag‚‚‚
Ag distance is 3.41 Å, which is slightly shorter than the than
the sum of the van der Waals radii of two silver atoms, 3.44
Å.
Figure 7. ORTEP figure of 3 (50% probability ellipsoids).
carried out under exactly the same conditions including
solvent system, metal-to-ligand ratio, and temperature.
Structural Analysis of [Ag(L10)]SO3CF3 (5). The idea
behind the use of ligand L10 is to control supramolecular
motifs through 3,3′-bibenzoacetylene-type lignds. It is well-
known that the relative orientations of the coordination
donors and also the different bridging spacing might result
in unusual building blocks, which can lead to the construction
of supramolecular motifs that have not been achieved using
normal rigid linear organic ligands. Our previous studies
demonstrated that five-membered 1,3,4-oxadiazole-bridged
Figure 8. Ag2(L9)2 building blocks bound together by Ag-π interactions into a two-dimensional net in 3.
Figure 9. Side view of two layers in 3.
Inorganic Chemistry, Vol. 44, No. 19, 2005 6599

Dong et al.
Figure 10. ORTEP figure of 4 (50% probability ellipsoids).
Figure 12. ORTEP figure of 5 (50% probability ellipsoids).
dimensional network, namely ZnF(3-amino-1,2,4-triazole),
was reported very recently.15e Similar regular honeycomblike
channels have been found. The channels have a 12 × 12 Å
dimension that is larger than that of in 5. To our knowledge,
compound 5 reported herein is the first example of a non-
interpenetrating three-dimensional honeycomblike channel-
containing network formed by one-dimensional chains
through interchain π-π interactions. Compared to 1, the
polymeric pattern changes from a two-dimensional net in 1
to a π-π interaction driven three-dimensional framework
in 5, indicating of the remarkable influence of the different
orientations of the -CtCH donors on the phenyl rings.
Structural Analysis of [Ag(L10)(H2O)0.5]BF4‚0.5H2O
(6). To explore the effect of the counterion on the long-range
order of the Ag(I)-L10 coordination polymer, the weakly
-
Figure 11. Two-dimensional net in 4. Uncoordinated BF4 counterions
are located in the channels.
The architectural pattern of 5 demonstrates a one-
dimensional chain motif composed of the {Ag2(L10)2} “X-
shaped” moieties linked via the two crystallographic equiva-
lent Ag-π bonds (Figure 13). These chains extend along
the crystallographic c axis and, moreover, stack together in
a face-to-face fashion through a weak interchain π-π
interaction (3.5 Å) along the crystallographic b axis (Figure
14) to generate a three-dimensional network containing
almost regular honeycomblike channels being filled with
coordinated SO3CF3- counterions (Figure 15). The effective
cavity size of the channel is ca. 6 × 8 Å. The shortest
interchain Ag‚‚‚Ag separation is 5.9 Å.
The assembly of a honeycomblike is challenging since the
hexagon represents the one of the most common motifs in
nature.14 However, synthetic noninterpenetrating three-
dimensional networks with honeycomblike cross sections are
still unusual, although some two-dimensional honeycomblike
nets, such as [Ni(BTC)]3[BTC]2‚14H2O‚2C5H5N (BTC ) 1,
3, 5-benzenetricarboxylate) and [Ag(TCB)(CF3SO3)] (TCB
) 1, 3, 5-tricyanobenzene),16 have been previously obtained.
In the solid state, these two-dimensional nets stack in parallel
and generate honeycomblike channels. An interesting three-
-
coordinating BF4 anion was used instead of the more
strongly coordinating SO3CF3- anion. Crystallization of L10
with AgBF4 in the same mixed solvent system at room
temperature afforded polymeric compound 6 in 85% yield.
Compound 6 is air stable. Single-crystal X-ray analysis of
compound 6 showed that the silver atom resides in a distorted
{AgN2Oπ} tetrahedral coordination environment, consisting
of two oxadiazole N donors (Ag(1)-N(1) ) 2.301(5) and
Ag(1)-N(2) ) 2.303(5) Å), one O donor (Ag(1)-O(3) )
2.515(5) Å) from a coordinated water molecule, and one pair
of π electrons from one η2-CtCH group (Ag(1)-C(6) )
2.287(8) and Ag(1)-C(5) ) 2.411(7) Å). It is worth pointing
(15) (a) Choi, H. J.; Suh, M. P. J. Am. Chem. Soc. 1998, 120, 10622. (b)
Gardner, G. B.; Venkataraman, D.; Moore, J. S.; Lee, S. Nature 1995,
374, 792. (c) Abrahams, B. F.; Hoskins, B. F.; Liu, J.; Robson, R. J.
Am. Chem. Soc. 1991, 113, 3045. (d) Abrahams, B. F.; Hoskins, B.
F.; Robson, R. J. Chem. Soc., Chem. Commun. 1990, 60. (e) Su, C.-
Y.; Goforth, A. M.; Smith, M. D.; Pellechia, P. J.; zur Loye, H.-C. J.
Am. Chem. Soc. 2004, 126, 3576.
(16) The pore dimensions described here are crystallographic scalar
quantities and do not account for the van der Waals radii of the atoms
defining the pore.
(14) Ozin, G. A. Acc. Chem. Res. 1997, 30, 17.
6600 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Figure 13. “X-shaped” building block for a one-dimensional chain in 5. The Ag‚‚‚Ag distances are shown as dotted lines.
Figure 14. Two sets of one-dimensional chains stacking together through interchain π-π interactions.
-
Figure 15. View of the honeycomblike channel-containing three-dimensional structure in 5. SO3CF3 anions are located in channels.
out that there are two independent L10 ligands in 6. The
first type of L10 ligand acts as a tetradentate coordination
spacer, whereas the second one displays a bidentate ligand
(Figure 16). Two silver atoms are connected to each other
by four oxadiazole N donors from the first and second types
of L10 ligand, respectively, giving rise to a {Ag2(L10)2}
moiety, in which these two silver atoms are bridged together
by a coordinated water molecule.
F‚‚‚H-C hydrogen bonds. Every two sets of H-bonds extend
along the crystallographic a and c axes (Figure 18),
respectively. The F(5)‚‚‚H(6) and F(6)‚‚‚H(17) distances are
2.394(5) and 2.632(6) Å, respectively. The corresponding
F(5)‚‚‚C(6) and F(6)‚‚‚C(17) distances are 3.14(5) and
3.21(4) Å, respectively, and the corresponding F(5)‚‚‚H(6)-
C(6) and F(6)‚‚‚H(17)-C(17) angles are 132.58(5) and
123.98(4)°, respectively. As shown in Figure 19, one-
dimensional zigzag chains are linked together by these four
sets of F‚‚‚H-C bonds to generate a novel noninterpenetrat-
ing three-dimensional H-bonded framework (Figure 19). The
three-dimensional framework consists of two different kinds
of channels, i.e., big ellipse-like and rectangle-like channels,
extending along the crystallographic c axis. The crystal-
In the solid state, two sets of {Ag2(L10)2O} building
blocks rightabout orientate and are linked by two sets of
terminal Ag-π bonds to form a one-dimensional zigzag
chain running along the crystallographic b axis (Figure 17).
-
The uncoordinated BF4 anions are located between these
zigzag chains and bound to them by four sets of interchain
Inorganic Chemistry, Vol. 44, No. 19, 2005 6601

Dong et al.
and counterion on the long-range order of the Ag(I)-L10
-
coordination polymer, xylene and ClO4 were used instead
-
of benzene and BF4 to perform the reaction. When a
solution of L10 in methylene chloride was treated with
AgClO4 in xylene, using a metal-to-ligand ratio of 1:1,
compound 7 was obtained as colorless crystals in 85% yield.
Single-crystal X-ray analysis revealed that there are two
crystallographic independent Ag(I) atoms in 7, and they are
all located in a distorted {AgN2Oπ} coordination sphere. As
shown in Figure 21, the coordination environment of each
silver atom is defined by two Noxadiazole donors from two L10
ligands, one O donor from a coordinated water molecule,
and a π-donor from a -CtCH moiety. For Ag(1) and Ag(2)
centers, the Ag-N and Ag-O bond lengths lie in a range
of 2.277(3)-2.335(3) and 2.519(3)-2.523(3) Å, respectively.
The Ag-C bond distances are in the range of 2.288(4)-
2.451(3) Å. All the bond distances herein are similar to those
corresponding bond lengths of 6. Compared to 6, the same
one-dimensional zigzag chain consisting of the same
{Ag2(L10)2O} building blocks has been found (Figure 22).
It is worthy to point out that the hydrogen-bonding system
in 7 is different from that of 6. As shown in Figure 23, one-
dimensional zigzag chains are linked together by two sets
of equivalent O-H‚‚‚O hydrogen bonds along the crystal-
lographic c axis into a two-dimensional net. The correspond-
ing O‚‚‚H, O‚‚‚O, and -O‚‚‚H-O data are 2.62(3) and
3.02(3) Å and 111.98(5)°, respectively. In addition, O‚‚‚H-C
hydrogen-bonding interactions are present in 3, too. As
shown in Figure 24, the O‚‚‚H-C hydrogen-bonding system
along the crystallographic c axis involves O(11) and O(10)
of the ClO4- anions and H(3) and H(33) on the phenyl and
acetylene groups of L10 ligand of the neighboring chains
(O(10)‚‚‚H(3), C(3)‚‚‚O(10), and -O(10)‚‚‚H(3)-C(3) are
2.49(3) and 3.30(3) Å and 147.23(5)°, respectively; O(11)‚‚‚
H(33), C(33)‚‚‚O(11), and -O(11)‚‚‚H(33)-C(33) are 2.53(3)
and 3.19(3) Å and 128.26(5)°, respectively). The O‚‚‚H-C
hydrogen-bonding system along the crystallographic a axis
Figure 16. ORTEP figure of 6 (50% probability ellipsoids).
lographic dimensions16 are 15.17 × 9.31 and 5.91 × 4.26
Å, respectively. The large ellipse-like channels are guest free,
while the small rectangle-like channels are filled with water
guest molecules and hydrogen bonded to the framework
through the weak F‚‚‚H-O hydrogen bonds (Figure 20). The
corresponding F‚‚‚H, F‚‚‚O, and -F‚‚‚H-O data are 2.62(3)
and 3.02(3) Å and 111.98(5)°, respectively. The existence
and structural importance of weak C-H‚‚‚X hydrogen-
bonding interactions are now well established17 and are
observed in many compounds, such as the N‚‚‚H-C inter-
action in 1,3,5-tricyanobenzene-hexamethylbenzene,18a the
O‚‚‚H-C interaction in (C14H12N2)[Cu(opba)]‚3H2O and
Na2(C12H12N2)[Cu(opba)]2‚4H2O (opba ) o-phenylenebis-
(oxamate)),18a and the F‚‚‚H-C interaction in 11-(trifluoro-
methyl)-15,16-dihydrocyclopenta[R]phenanthren-17-one.19
These hydrogen bonds, although weak, contribute signifi-
cantly to the structural organization of 6 in the crystalline
state.
Structural Analysis of {[Ag2(L10)2(H2O)]ClO4}‚(o-
xylene) (7). To investigate the templating effect of the solvent
Figure 17. Two sets of conversely orientated {Ag2(L10)2O} building blocks being linked by Ag-π bonds into a one-dimensional zigzag chain.
Figure 18. Interchain F‚‚‚H-C hydrogen-bonding systems. The view is shown down the crystallographic b axis.
6602 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Figure 19. H-bonded three-dimensional framework of 6.
Figure 21. ORTEP structure of 7 (50% probability ellipsoids).
o-xylene molecules. As shown herein, only o-xylene mol-
ecules other than m- and p-xylol molecules have been
1
clathrated during the crystallization in xylene of 7. The H
Figure 20. Guest water molecules located in the small rectangle-like
channels and fixed by F‚‚‚H-O hydrogen bonds.
NMR (DMSO-d6) of 7 showed a single peak at 2.19 ppm
and the multiple peaks in the range of 7.02-7.18 ppm, which
was attributed to the proton on the clathrated o-xylene
molecules. This could be an additional evidence for this novel
crystallized process. Such crystallization of 7 in xylene could
be considered as shape-selective process,20 and compound
7 might find potential applications such as xylene isomers
purification. Further studies are needed to elucidate the
mechanism why compound 7 can selectively clathrate
o-xylene but not m- and p-xylol. A systematic investigation
is underway on the inclusion properties and guest exchange
-
consists of O(4) and O(6) of the ClO4 anions and H(21)
and H(23) on the phenyl groups of L10 ligand of the adjacent
chains (O(4)‚‚‚H(21), C(21)‚‚‚O(4), and -O(4)‚‚‚H(21)-
C(21) are 2.57(3) and 3.23(3) Å and 128.65(5)°, respectively;
O(6)‚‚‚H(23), C(23)‚‚‚O(6), and -O(6)‚‚‚H(23)-C(23) are
2.59(3) and 3.50(3) Å and 168.37(5)°, respectively). Thus,
the strong O-H‚‚‚O and weak O-H‚‚‚C hydrogen bonds
serve as the glue to link one-dimensional chains into a three-
dimensional hydrogen-bonded infinite structure. As shown
in Figure 25, the noninterpenetrating three-dimensional
network with rhombic channels (effective cross-section of
ca. 14 × 13 Å) extends along the crystallographic a axis, in
which the o-xylene molecules are located as the guest. It is
interesting that compound 7 exhibits a significant affinity to
(18) (a) Reddy, D. S.; Goud, B. S.; Panneerselvam, K.; Desiraju, G. R. J.
Chem. Soc. Commun. 1993, 663. (b) Unamuno, I.; Gutie´rrez-Zorrilla,
J. M.; Luque, A.; Roma´n, P.; Lezama, L.; Calvo, R.; Rojo, T. Inorg.
Chem. 1998, 37, 6452.
(19) Sano, Y.; Tanaka, M.; Koga, N.; Matsuda, K.; Iwamura, H.; Rabu,
P.; Drillon, M. J. Am. Chem. Soc. 1997, 119, 8246.
(20) (a) Kosal, M. E.; Chou, J.-H.; Wilson, S. R.; Suslick, K. Nature 2002,
1, 121. (b) Fujita, M.; Kwon, Y. J.; Washizu, S.; Ogura, K. J. Am.
Chem. Soc. 1994, 116, 1151.
(17) Desiraju, G. R. Acc. Chem. Res. 1996, 29, 441.
Inorganic Chemistry, Vol. 44, No. 19, 2005 6603

Dong et al.
Figure 22. One-dimensional zigzag chain composed of {Ag2(L10)2O} building block in 7.
Figure 23. One-dimensional chains of 7 connected to each other by two sets of equivalent O-H‚‚‚O hydrogen bonds.
°C (Figure 27), which is consistent with the results of TGA.
The X-ray powder diffraction (XRD) pattern of thermally
desolvated sample of 7 is compared with that of as-
synthesized, solvent-containing 7 in Figure 28. The XRD
pattern after heating show that the shapes and intensities of
some reflections are slightly changed relative to that of the
original sample. This indicates that the porous framework
of 7 is maintained after the guest removal.
1
IR, H NMR, and UV/Vis Spectra. The IR spectra of
all complexes display the characteristic strong νCtC-H band
around 3280 cm-1, corroborating the -CtCH being the
terminal functional group in L9 and L10. IR spectra of
complexes 3 and 4 reveal weak νCtC vibrations of the
coordinated -CtCH groups at 2072-2109 cm-1, which is
shifted by ∼98 cm-1 to lower energy compared to the free
alkynes (2169-2170 cm-1). The IR of 1 and 2 and 5-7
show two bands in the CtC stretching region at 2169-2170
and 2072-2109 cm-1, respectively. The bands in the region
of 2169-2170 cm-1 correspond to the uncoordinated -Ct
CH groups, while the bands in the region of 2072-2109
cm-1 correspond to the coordinated -CtCH groups. Such
a shift of νCtC upon η2-coordination in complexes 1-7 is
similar to what is generally observed for alkynes being two-
electron π-donors to the Ag(I) center.21
Figure 24. O‚‚‚H-C hydrogen-bonding systems cross-linking the one-
dimensional chains extending along the crystallographic a and c axes.
of 7. Thermogravimetric analyses traces of 7 (Figure 26)
show a weight loss of 1.66% from 50 to 90 °C corresponding
to the loss of the water molecules (calcd 1.67%). A second
weight loss of 9.6% from 140 to 229 °C corresponds to
removal of the guest o-xylene molecules (calculated 9.8%).
The third weight loss, observed from 250 to 392 °C,
corresponds to the release of the one of the two ligands of
L10 (obsd 24.5%, calcd 25.0%). The forth weight loss (obsd
24.1%, calcd 25.0%) above 400 °C corresponds to the release
Compounds 1-7 are insoluble in common organic solvents
due to their polymeric nature. They are soluble in CH3CN
and slightly soluble in DMSO and DMF. The 1H NMR and
UV/vis spectra of complexes 1-7 in solution are identical
with those of the free ligands, which indicates all complexes
(21) (a) Lin, Y.-Y.; Lai, S.-W.; Che, C.-M.; Cheung, K.-K.; Zhou, Z.-Y.
Organometallics 2002, 21, 2275. (b) Chui, S. S. Y.; Ng, M. F. Y.;
Che, C.-M. Chem.sEur. J. 2005, 11, 1739.
1
of the remaining L10 ligand. H NMR spectra of 7 show
that all o-xylene guest molecules could be removed at ∼200
6604 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Figure 25. H-bonded three-dimensional network of 7. o-Xylene guest molecules (shown as space-filling) are located in the rhombic channels.
Figure 26. TGA trace of 7.
were dissolved to dissociate into oligomers or the starting
materials in solution.
Theoretical Calculations. To gain a deeper insight into
the coordination behavior of this type of ligands, we
performed ab initio Mulliken population analysis on ligands
L9 and L10.22 For this study, DFT calculations with the
B3LYP functional and the 6-31G(d) basis set were used. Full
geometry optimizations without any symmetry constraints
were carried out. Harmonic frequencies were also calculated
Figure 27. 1H NMR spectra of 7 in DMSO-d6. (a) 1H NMR spectrum of
at the optimized structure at the same level of accuracy, and
original sample of 7 recorded at room temperature is shown. (b) The solid
no imaginary frequency was found to confirm the resulting
structure is a minimum. The calculations were performed
with the Gaussian 98 software on a Pentium computer. The
calculated results of L9 show that the values of total atomic
charges for two terminal carbon atoms are negative (-0.5971),
which indicates the strong coordination tendency toward to
soft silver atom. As expected, the total atomic charges of
two nitrogen (-0.3497) and one oxygen (-0.4913) atoms
on central oxadiazole ring are negative too, which is usual
for electronegative heteroatoms.
sample of 7 was heated to 90 °C and then dissolved in DMSO-d6, and the
spectrum was recorded at ambient temperature. (c) The solid sample of 7
was heated to 200 °C and then dissolved in DMSO-d6, and the spectrum
was recorded at ambient temperature.
L10 is different from L9. The calculation results of L10
show that the energies of three possible conformations of
L10 in either gas or benzene solution are almost identical
(Table 10). Thus, these three conformations I-III could be
concomitant in gas or benzene solution (Chart 2). As shown
above, L10 adopts conformation I to bind the Ag(I) atom in
5, while it adopts both conformations I and III to bind Ag(I)
atoms in compounds 6 and 7. However, no conformation II
was found in compounds 5-7. L10 is similar to L9 in that
the atomic charges of the terminal carbon atoms and two
(22) (a) Bianco, A,; Bertarelli, C.; Rabolt, J. F.; Zerbi, G. Chem. Mater.
2005, 17, 869. (b)Nandina, G.; Sathyanarayana, D. N. J. Mol. Struct.
(THEOCHEM) 2002, 579, 1.
Inorganic Chemistry, Vol. 44, No. 19, 2005 6605

Dong et al.
and thin gold wire (0.2 mm in diameter which is smaller
than those of single crystals) on the piece of organic glass
using gold paste. Two gold wires extended from these two
electrodes were connected to an Agilent Technologies
4294A-ATO-20150. The scan range of 5 ( 0.1 MHz was
chosen during the measurement. The conductance (G) and
susceptance (B) values were obtained totally on the basis of
401 scanning dots. The resistivity (F) of the complexes was
obtained depending on the formula of S/(LG) (S ) πr2, L )
length of the single crystals). The dielectric constant (ꢀr) of
complexes was obtained depending on the formula of BL/
(2πfs). The primary result indicates that metal-organic
complexes 2, 5, and 7 behave as typical semiconductors with
a resistivity (F) value lying in the range of 0.302 × 102-
2.926 × 102 Ω‚m (Table 11). The corresponding dielectric
constants (ꢀr) of 2, 5, and 7 were obtained in the range of
12.4 × 102-148.3 × 102.
Figure 28. X-ray powder diffraction patterns of 7: (a) original crystals
of 7; (b) 7 heated to 200 °C.
nitrogen and one oxygen atoms on central oxadiazole ring
of L10 are negative (Table 10), which provide a supportive
trend for the current results and discussion.
Electrical Conductivity. Synthesis of single-component
molecular coordination complexes by the judicious choice
of organic spacers and metal centers can be an efficient
method for obtaining new types of conductive materials,23
for example, [M(dimt)2]2-type molecular complexes (M )
Ni(II), Pd(II), Pt(II), Cu(II), and so on; dimt ) 4,5-
dimercapto-1,3-dithiole-2-thione).24 Some of them have been
confirmed to be semiconductors or superconductors. Up to
date, a number of molecular-based transition metal com-
plexes with interesting electrical conductivity have been
reported. However, the study of conductive properties on
polymeric coordination complexes has received considerably
less attention. To explore the electrical conductive properties
of these new polymeric complexes, the electrical conductive
experiment were performed on compounds 2, 5, and 7 in
the solid state. The conductivity measurements of 2, 5, and
7 were performed on single crystals at a direction on the ac
plane for 2 and ab plane for 5 and 7, respectively. The single
crystal was fixed between a gold plate (10 × 4 × 1 mm)
Luminescent Properties of L9, L10, and 1-7. Inorganic-
organic hybrid coordination polymers have been investigated
for fluorescence properties and for potential applications as
luminescent materials, such as light-emitting diodes (LEDs).25
Owing to the higher thermal stability of inorganic-organic
coordination polymers and the ability of affecting the
emission wavelength of organic materials, syntheses of
inorganic-organic coordination polymers by the judicious
choice of conjugated organic spacers and transition metal
centers can be an efficient method for obtaining new types
of electroluminescent materials, especially for d10 or d10-
d10 systems26 and oxadiazole-containing complexes.27 We
have been exploring the luminescent properties of L1-L8
and organic-inorganic coordination polymers and supra-
molecular complexes based on them in the solid state. The
results indicate that emission colors of organic spacers L1-
L8 were affected by their incorporation into metal-containing
coordination compounds. The luminescent properties of L9
Table 10. Calculation Results for L10a
isomer I state
isomer II state
isomer III state
param
gas
C6H6
gas
C6H6
gas
C6H6
energy (au)
dipole moment
charges
-876.2715
3.9620
-876.2721
4.4311
-876.2718
3.3885
-876.2723
3.8667
-876.2721
2.7998
-876.2725
3.2558
atom N1
atom N2
atom O3
atom C4
-0.2808
-0.2808
-0.5117
0.0613
-0.2843
-0.2843
-0.5102
0.0635
-0.2839
-0.2811
-0.5100
0.0577
-0.2870
-0.2842
-0.5087
0.0546
-0.2841
-0.2841
-0.5079
0.0578
-0.2870
-0.2870
-0.5069
0.0552
atom C5
atom C6
-0.5066
0.0613
-0.5102
0.0635
-0.5097
0.0614
-0.5040
0.0634
-0.5089
0.0578
-0.5044
0.0552
atom C7
-0.5066
-0.5102
-0.5070
-0.5105
-0.5089
-0.5044
a Dielectric constant of benzene solution: 2.247. Solute radii: (I) 5.19 Å; (II) 5.23 Å; (III) 5.15 Å
Chart 2. Possible Conformations I-III of L10
6606 Inorganic Chemistry, Vol. 44, No. 19, 2005

Organometallic Coordination Polymers
Figure 29. Photoinduced emission spectra of L9 (red) and L10 (purple) in CH3CN.
Table 11. λex/λem (nm) Luminescent Properties of L9, L10, and 1-7
slight enhancement of the fluorescence intensity is realized.
In CH3CN, almost no difference has been found between
the ligands’ and complexes’ emission colors. This implies
that the polymeric complexes disaggregate into oligomers
or starting materials in acetonitrile.
in the Solid State and CH3CN
compd
solid state
CH3CN
compd
solid state
CH3CN
L9
L10
1
2
3
203/387
204/386
202/424
202/422
202/423
205/361
202/350
207/358
207/357
206/356
4
5
6
7
202/425
202/395
204/397
202/397
211/360
203/348
211/347
202/357
Conclusions
Table 12. Electrical Conductivity of Compounds 2, 5, and 7a
This study demonstrates that the bent oxadiazole bridging
benzoacetylene organic ligands 2,5-bis(4-ethynylphenyl)-
1,3,4-oxadiazole (L9) and 2,5-bis(3-ethynylphenyl)-1,3,4-
oxadiazole (L10) are capable of coordinating metal centers
with both Noxadiazole and terminal -CtCH π-donors and
generate novel organometallic coordination polymers. Seven
new polymeric compounds 1-7 were synthesized from
solution reactions of L9 and L10 with various Ag(I) salts.
The relative orientation of the π-donors on the phenyl groups
and the five-membered oxadiazole spacing in L9 and L10
resulted in the unusual building blocks, leading to the
construction of polymeric motifs which have not been
obtained using normal linear rigid bidentate organic ligands
and known bent spacers L1-L8. The results reported herein
demonstrate that the use of organic spacers containing both
the -CtCH moiety and coordinating heterocyclic group as
precursors to bind transition metal ions is in fact a new
approach for the formation of novel organometallic molecular
and supramolecular networks with interesting physical
L
G
(ns)
B
(µs)
r
10-2
F
compd (µm)
(10-5 Ω-1‚cm-1
)
(Ω‚m) 10-2ꢀr
2
5
7
133 40.3248 5.49724
460 45.2800 7.86032
330 49.9280 7.92367
3.4176
33.151
26.223
2.926 148.3
0.302
0.381
17.1
12.4
a The resistivities (F) of 2, 5, and 7 were obtained depending on the
formula of S/(LG) (S ) πr2, L ) length of the single crystals); dielectric
constants (ꢀr) of 2, 5, and 7 were obtained depending on the formula of
BL/(2πfs).
and L10 and polymeric compounds 1-7 were investigated
in CH3CN and the solid state. In the solid-state case, single
crystalline samples were used for the measurements. The
ground microcrystalline samples were housed in the solid
sample quartz carrier. The excitation and emission slit widths
are 5 nm. The fluorescence spectra of L9, L10, and 1-7
are summarized in Table 11. As indicated in Figure 29, in
CH3CN, L9 and L10 present one maximum at 361 nm for
L9 and 350 nm for L10. In the solid state, L9 and L10
exhibit one emission maximum at 387 and 386 nm, respec-
tively. In the solid state, as shown in Table 12, the emission
colors of the free ligands were significantly affected by their
incorporation into the Ag-containing polymeric compounds
1-7, as evidenced by the large shift in the emission. Only
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Inorganic Chemistry, Vol. 44, No. 19, 2005 6607

Dong et al.
properties. We are currently expanding this result by prepar-
ing new longer symmetric and unsymmetric oxadiazole-
containing ligands based on L9 and L10 by Pd-catalyzed
reactions containing different terminal coordination groups
and having different orientations of the terminal coordination
sites. New coordination polymers with novel polymeric
patterns and interesting chemical and physical properties
based on these ligands will be reported soon.
Acknowledgment. We are grateful for financial support
from the National Natural Science Foundation of China
(Grant No. 20371030) and Shangdong Natural Science
Foundation (Grant No. Z2004B01).
Supporting Information Available: Crystallographic data in
cif format. This material is available free of charge via the Internet
at http://pubs.acs.org.
IC0508223
6608 Inorganic Chemistry, Vol. 44, No. 19, 2005