Two- and three-dimensional silver acetylide frameworks with high-nuclearity silver cluster building blocks assembled using a bifunctional (4-ethynylphenyl)diphenyl phosphine ligand

Article abstract of DOI:10.1016/j.ica.2017.01.030

A bifunctional ligand precursor (4-ethynylphenyl)diphenyl phosphine was synthesized and used for constructing silver acetylide frameworks. Its reaction with Ag(I) in the presence of triethylamine afforded silver acetylide [AgL]_n, in which L = Ph₂P-C₆H₄-4-C[tbnd]C^?could act as a bifunctional ligand bearing both phenylethynide and phosphine binding sites for Ag(I). Reactions of [AgL]_nand AgCF₃CO₂under different conditions gave four silver acetylides. They are [Ag₁₈L₈(CF₃COO)₆(HCO₃)₄(DMF)₄]_n(1, DMF = dimethylformamide), [Ag₂₀L₈(CF₃COO)₁₂(DMF)₆]_n(2), [Ag₁₇L₆(CF₃COO)₉(HCO₃)₂]_n(3), and [Ag₁₇L₆(CF₃COO)_9.58(HCO₃)_1.42]_n(4). Crystallographic studies revealed that complex 1 crystallized in the triclinic space group P1ˉ with a = 14.1252(9) ?, b = 18.6012(12) ?, c = 25.2137(17) ?, α = 108.340(2)°, β = 95.386(2)°, γ = 95.535(2)°, V = 6204.6(7) ?³, and Z = 1. Complex 2 crystallized in the monoclinic space group C2/c with a = 48.046(4) ?, b = 14.1860(10) ?, c = 34.943(2) ?, β = 98.315(3)°, V = 23,566(3) ?³, and Z = 4. Complex 3 crystallized in the triclinic space group P1ˉ with a = 15.5690(7) ?, b = 16.7707(8) ?, c = 34.0810(16) ?, α = 93.4040(10)°, β = 100.3690(10)°, γ = 94.8250(10)°, V = 8697.1(7) ?³, and Z = 2. Complex 4 crystallized in the triclinic space group P1ˉ with a = 15.5396(6) ?, b = 16.7595(7) ?, c = 34.0225(15) ?, α = 93.8140(10)°, β = 100.1000(10)°, γ = 94.9770(10)°, V = 8660.2(6) ?³, and Z = 2. The presence of Ag(I)–ethynide, Ag(I)–P and Ag(I)–Ag(I) bonding interactions makes all four silver acetylides to have two- and three-dimensional framework structures with unusual high-nuclearity silver cluster building blocks.

Full text of DOI:10.1016/j.ica.2017.01.030

Inorganica Chimica Acta 461 (2017) 57–63
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Research paper
Two- and three-dimensional silver acetylide frameworks with
high-nuclearity silver cluster building blocks assembled using
a bifunctional (4-ethynylphenyl)diphenyl phosphine ligand
Shaokang Zhang a,1, Zongyao Zhang b,1, Rui Cao a,b,
⇑
a School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710119, China
b Department of Chemistry, Renmin University of China, Beijing 100872, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A bifunctional ligand precursor (4-ethynylphenyl)diphenyl phosphine was synthesized and used for
constructing silver acetylide frameworks. Its reaction with Ag(I) in the presence of triethylamine afforded
silver acetylide [AgL]n, in which L = Ph2P-C6H4-4-C„CÀ could act as a bifunctional ligand bearing both
phenylethynide and phosphine binding sites for Ag(I). Reactions of [AgL]n and AgCF3CO2 under different
conditions gave four silver acetylides. They are [Ag18L8(CF3COO)6(HCO3)4(DMF)4]n (1,
DMF = dimethylformamide), [Ag20L8(CF3COO)12(DMF)6]n (2), [Ag17L6(CF3COO)9(HCO3)2]n (3), and
Received 7 October 2016
Received in revised form 15 December 2016
Accepted 10 January 2017
Keywords:
[Ag17L6(CF3COO)9.58(HCO3)1.42
] (4). Crystallographic studies revealed that complex 1 crystallized in
n
Bifunctional ligand
Silver acetylide
Coordination polymer
X-ray structure
Silver cluster
ꢀ
the triclinic space group P1 with a = 14.1252(9) Å, b = 18.6012(12) Å, c = 25.2137(17) Å,
a = 108.340(2)°,
b = 95.386(2)°,
c
= 95.535(2)°, V = 6204.6(7) Å3, and Z = 1. Complex 2 crystallized in the monoclinic space
group C2/c with a = 48.046(4) Å, b = 14.1860(10) Å, c = 34.943(2) Å, b = 98.315(3)°, V = 23,566(3) Å3, and
ꢀ
Z = 4. Complex 3 crystallized in the triclinic space group P1 with a = 15.5690(7) Å, b = 16.7707(8) Å,
c = 34.0810(16) Å,
Complex
c = 34.0225(15) Å,
a
= 93.4040(10)°, b = 100.3690(10)°,
c
= 94.8250(10)°, V = 8697.1(7) Å3, and Z = 2.
ꢀ
4
crystallized in the triclinic space group P1 with a = 15.5396(6) Å, b = 16.7595(7) Å,
a
= 93.8140(10)°, b = 100.1000(10)°, c
= 94.9770(10)°, V = 8660.2(6) Å3, and Z = 2. The
presence of Ag(I)–ethynide, Ag(I)–P and Ag(I)–Ag(I) bonding interactions makes all four silver acetylides
to have two- and three-dimensional framework structures with unusual high-nuclearity silver cluster
building blocks.
Ó 2017 Elsevier B.V. All rights reserved.
1. Introduction
simple but strong Ag(I)–P coordination interactions, have been fre-
quently used as capping ligands to confine the silver cluster to a
Silver acetylides have attracted continuous attention because of
their intrinsic and fundamental importance in structural [1–6] and
photophysical chemistry [7–12], and also their potential applica-
tions in organic transformation [13–17], catalysis [18–22], and
material sciences [23–26]. Extensive efforts have resulted in the
synthesis and structural characterization of many silver acetylides,
from which diverse Ag(I)–ethynide coordination modes and
metallophilic [27] Ag(I)–Ag(I) interactions have been demon-
strated [1–5,28–39]. However, unmodified silver acetylides usually
aggregate to form organometallic polymers [6], which are not sol-
uble and precipitate immediately upon formation. As a result, in
the synthesis of these complexes, phosphine ligands, which have
certain size by preventing its uncontrolled and infinite growth
[8,9,12,40–45].
Ligand design therefore plays a critical role in the research of
silver acetylides. In addition to simple ligands containing one ethy-
nide or one phosphine binding site for Ag(I), alkynyl ligands that
have two or more ethynide groups [31,32,37–39,46–49] and also
di- and triphosphine ligands [9,12,40–42] have been explored for
the construction of silver acetylides with various complicated
structures largely due to the presence of additional coordination
and bridging modes. However, silver acetylides reported so far in
general present either discrete cluster structures [1–4,33,36] or
polymeric structures with small silver cluster building blocks
[6,31,34,35,37,46,48–50]. In order to make new silver acetylides
with more structural diversities, we are interested in combining
the benefits of both ethynide and phosphine binding sites in one
single ligand. The resulted bifunctional ligand can use the ethynide
⇑
Corresponding author at: School of Chemistry and Chemical Engineering,
Shaanxi Normal University, Xi’an 710119, China.
E-mail address: ruicao@ruc.edu.cn (R. Cao).
These authors contributed equally to this work.
1
http://dx.doi.org/10.1016/j.ica.2017.01.030
0020-1693/Ó 2017 Elsevier B.V. All rights reserved.

58
S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
part to create silver clusters and use the phosphine part to control
the silver cluster size. Importantly, unlike using individual alkynyl
and phosphine ligands, the assembly of both binding sites in one
single ligand is expected to form silver acetylide frameworks
through bridging Ag(I)–P-C6H4-4-C„C–Ag(I) linkages.
Herein we report the design of (4-ethynylphenyl)diphenyl
phosphine as a ligand precursor and its uses in the synthesis and
assembly of silver acetylides. Upon deprotonation of the acetylene
unit, the resulted bifunctional Ph2P-C6H4-4-C„CÀ (L) ligand can
interact with Ag(I) through both ethynide and phosphine coordina-
tion sites. Four silver acetylide complexes were isolated and struc-
turally characterized, including [Ag18L8(CF3COO)6(HCO3)4(DMF)4]n
(1, DMF = dimethylformamide), [Ag20L8(CF3COO)12(DMF)6]n (2),
2.4. Preparation of Ph2P-C6H4-4-C„CH
To a methanol (80 mL) and dichloromethane (10 mL) solution of
Ph2P-C6H4-4-C„C-SiMe3 (0.95 g, 2.66 mmol), was added K2CO3
(0.74 g, 5.33 mmol). The suspension was stirred at room tempera-
ture for 2 h, and was then filtered. The crude product was purified
by silica gel chromatography to give
a white solid (0.75 g,
2.61 mmol, 98% yield) 1H NMR (CDCl3): d 7.48–7.20 (m, 14H),
3.11 (s, 1H). 13C NMR (CDCl3): d 138.91, 136.72, 133.93, 133.46,
132.11, 129.08, 128.74, 122.42, 83.49, 78.38. 31P NMR (CDCl3): d
À4.8 (s).
2.5. Preparation of [AgL]n
[Ag17L6(CF3COO)9(HCO3)2]n
(3),
and
[Ag17L6(CF3COO)9.58
(HCO3)1.42]n (4). Crystallographic studies showed that all four com-
plexes represented very rare examples of silver acetylide frame-
works assembled using high-nuclearity silver cluster building
blocks. Complexes 1 and 2 have two-dimensional (2D) framework
structures, while complexes 3 and 4 have three-dimensional (3D)
framework structures.
Silver nitrate (67.95 mg, 0.4 mmol) was dissolved in acetonitrile
(8 mL). Triethylamine (40.48 mg, 0.4 mmol) and Ph2P-C6H4-4-
C„CH (0.11 g mg, 0.4 mmol) were added under stirring. The reac-
tion mixture was stirred for 2 d in the dark to give a white precip-
itate, which was collected by filtration. The product was then
washed by acetonitrile (3 Â 3 mL), dried in vacuo and was used
without further purification. Yield: 63.2% (99.43 mg).
2. Experimental section
2.6. Preparation of 1
2.1. Materials and methods
Complex [AgL]n (19.66 mg, 0.05 mmol) was dissolved in the
solution of AgCF3CO2 (44.18 mg, 0.2 mmol) in DMF (3 mL). The
reaction mixture was stirred overnight in the dark, and was filtered
to give a clear yellow solution. Slow vapor diffusion using diethyl
ether/petroleum ether (v/v = 1/1) afforded colorless crystalline
All reagents and solvents used were commercially available and
were used as received. Triethylamine and dichloromethane were
distilled with calcium hydride, tetrahydrofuran was distilled with
sodium strips. Manipulations of air- and moisture-sensitive
materials were performed under nitrogen gas using the standard
Schlenk line technique. 1H (400.0 MHz), 13C (100.0 MHz) and 31P
(121.4 MHz, with proton decoupling) NMR spectra were recorded
on a Brüker spectrometer operating at 400 MHz. Elemental analy-
ses were carried out with Vario EL III elemental analyzer. FT-IR
spectra were recorded with KBr pellets using a Bruker Tensor 27
spectrometer. Ligand precursor Ph2P-C6H4-4-C„CH was prepared
using a modified method reported previously [51].
plates of complex 1 in about 80% yield. Anal. Calcd. for C188H140
-
Ag18F18N4O28P8: C 41.55, H 2.60, N 1.03; found: C 41.72, H 2.76,
N 0.90.
2.7. Preparation of 2
Complex [AgL]n (19.66 mg, 0.05 mmol) was dissolved in the
solution of AgCF3CO2 (16.57 mg, 0.075 mmol) in DMF (3 mL). The
reaction mixture was stirred overnight in the dark, and was filtered
to give a clear yellow solution. Slow vapor diffusion using diethyl
ether afforded colorless crystalline plates of complex 2 in about
78% yield. Anal. Calcd. for C202H154Ag20F36N6O30P8: C 38.92, H
2.49, N 1.35; found: C 40.17, H 2.68, N 1.21.
2.2. Preparation of 4-bromo-(trimethylsilylethynyl)benzene
To an anhydrous triethylamine solution (30 mL), 4-iodo-bro-
mobenzene (2.0 g, 7.07 mmol) was dissolved at room temperature.
This solution was cooled in an ice bath, and Pd(PPh3)4 (0.20 g,
0.18 mmol) and CuI (34.28 mg, 0.18 mmol) were added. Cold
trimethylsilylacetylene solution (1.1 mL, 0.76 g, 7.78 mmol) was
then added in a dropwise manner. The mixture was stirred in an
ice bath for 1.5 h, and then saturated NH4Cl aqueous solution
(30 mL) was added. The product was extracted with CH2Cl2
(3 Â 50 mL), and the organic phases were combined and dried over
Na2SO4. Purification by chromatography on silica gel gave a white
solid (1.73 g, 6.82 mmol, 96% yield). 1H NMR (CDCl3): d 7.45–7.41
(m, 2H), 7.33–7.30 (m, 2H), 0.25 (s, 9H).
2.8. Preparation of 3
Complex [AgL]n (19.66 mg, 0.05 mmol) was dissolved in the
solution of AgCF3CO2 (49.70 mg, 0.225 mmol) in THF (3 mL). The
reaction mixture was stirred overnight in the dark, and was filtered
to give a clear yellow solution. Slow vapor diffusion using diethyl
ether/n-hexane (v/v = 1/1) afforded yellow crystalline prisms of
complex 3 in about 85% yield. Anal. Calcd. for C140H84Ag17F27O28P6:
C 35.42, H 1.78; found: C 35.69, H 1.91.
2.3. Preparation of Ph2P-C6H4-4-C„C-SiMe3
2.9. Preparation of 4
To an anhydrous THF solution (50 mL), 4-bromo-(trimethylsi-
lylethynyl)benzene (2.0 g, 7.9 mmol) was dissolved, and n-BuLi
(2.5 M, 3.16 mL, 7.9 mmol) was added under nitrogen at À78 °C.
The solution was stirred for 2 h before chlorodiphenylphosphine
(1.82 g, 8.23 mmol) was added. The reaction mixture was stirred
for an additional 2 h, and then the solvent was removed by rotary
evaporator under a reduced pressure. The residue was purified by
silica gel chromatography to afford a white powder (1.91 g,
5.33 mmol, 67% yield) 1H NMR (CDCl3): d 7.42–7.16 (m, 14H),
0.22 (s, 9H). 31P NMR (CDCl3): d À4.6 (s).
Complex [AgL]n (19.66 mg, 0.05 mmol) was dissolved in the solu-
tion of AgCF3CO2 (33.13 mg, 0.15 mmol) in THF (3 mL). The reaction
mixture was stirred overnight in the dark, and was filtered to give a
clear yellow solution. Slow vapor diffusion using diethyl ether/n-
hexane (v/v = 1/1) afforded yellow crystalline prisms of complex 4
in about 75% yield. Anal. Calcd. for C140.58H84Ag17F28.74O26.42P6:
C 35.46, H 1.78; found: C 35.63, H 1.89.
CAUTION! Silver acetylide complexes are potentially explosive and
should be handled with care and in small amounts.

S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
59
2.10. X-ray diffraction studies
reacted with n-BuLi at À78 °C, and then Ph2PCl was added drop-
wisely to give the coupling product Ph2P-C6H4-4-C„C-SiMe3. Sub-
sequent deprotection of the trimethylsilyl group using K2CO3 gave
the desired bifunctional ligand precursor bearing both acetylene
and phosphine moieties. The reaction of Ph2P-C6H4-4-C„CH and
AgNO3 in the presence of triethylamine afforded silver acetylide
[AgL]n polymers, which were not soluble in acetonitrile and precip-
itated immediately as white powders upon formation. This product
was collected by filtration, washed carefully by acetonitrile and
was dried in vacuo before the use in subsequent synthesis.
The reaction of [AgL]n and 4 equivalents of AgCF3CO2 in DMF
resulted in a clear yellow solution. Slow vapor diffusion of diethyl
ether/petroleum ether (v/v = 1/1) into the resulted DMF solution
afforded colorless crystalline plates of complex 1 in 5 d. The use
of a mixture of diethyl ether/petroleum ether was aimed to slow
down the vapor diffusion rate of diethyl ether, because the use of
pure diethyl ether caused the rapid precipitation. Similarly, the
reaction of [AgL]n and 1.5 equivalents of AgCF3CO2 in DMF gave
complex 2. If the same reaction between [AgL]n and AgCF3CO2
was conducted in tetrahydrofuran instead of DMF, the products
were 3 and 4 with the starting molar ratio of [AgL]n: AgCF3CO2 = 1:
4.5 and 1:3, respectively. All four complexes were isolated in mod-
erate yields (75–85%), and were structurally characterized by the
single crystal X-ray diffraction method.
Complete data for complexes 1–4 were collected. Single crystals
suitable for X-ray analysis were each coated with Paratone-N oil,
suspended in a small fiber loop, and placed in a cooled gas stream
on a Bruker D8 QUEST X-ray diffractometer. Diffraction intensities
were measured using graphite monochromated Mo K
(k = 0.71073 Å) at 153(2) K and a combination of u and
a
radiation
scans.
x
Data collection, indexing, data reduction, final unit cell refinements
and absorption corrections were carried out using APEX2 [52].
Absorption corrections were applied using the program SADABS
[53]. All structures were solved with direct methods using SHELXS
[54] and refined against F2 on all data by full-matrix least-squares
with SHELXL [55], following established refinement strategies.
In the structures of 1–4, all non-hydrogen atoms were
anisotropically refined. All hydrogen atoms binding to carbon were
included into the model at geometrically calculated positions and
refined using a riding model. The isotropic displacement parame-
ters of all hydrogen atoms were fixed to 1.2 times the U value of
the atoms they are linked to (1.5 times for methyl groups). Details
of the data quality and a summary of the residual values of the
refinements are listed in Table 1. Automatic structure evaluation
performed with PLATON as implemented in the CheckCIF routine
resulted in one level A alert concerning solvent accessible voids
for all four structures. Because of the framework structures of 1–
4, there are large spaces in their crystal structures. Therefore, it
is reasonable to have large solvent accessible voids in their crystal
X-ray structures.
3.2. Crystallographic studies of complex 1
ꢀ
Complex 1 crystallized in the triclinic space group P1 with
a = 14.1252(9) Å, b = 18.6012(12) Å, c = 25.2137(17) Å,
a = 108.340
3. Results and discussion
(2)°, b = 95.386(2)°,
c
= 95.535(2)°, V = 6204.6(7) Å3, and Z = 1
(Table 1). As shown in Fig. 1, complex 1 contains a Ag14 cluster,
which is located at the special position with a crystallographically
required inversion center. The Ag(I)–Ag(I) bond distances are in the
range of 2.8713(10) to 3.3329(11) Å, indicating the interactions
between these d10 Ag(I) ions [6,56]. The Ag14 cluster can be viewed
3.1. Synthesis of complexes 1–4
Ligand precursor Ph2P-C6H4-4-C„CH was made according to
the synthetic route shown in Scheme S1. Br-C6H4-4-C„C-SiMe3
Table 1
Crystal data and structure refinement parameters for complexes 1–4.
Complex
1
2
3
4
Molecular formula
Formula wt. (g molÀ1
Temperature (K)
Radiation (k, Å)
Crystal system
Space group
a (Å)
C
188H140Ag18F18N4O28P8
C202H154Ag20F36N6O30P8
6234.46
153(2)
0.71073
Monoclinic
C2/c
48.046(4)
14.1860(10)
34.943(2)
90
98.315(3)
90
23,566(3)
4
1.757
C140H84Ag17F27O28P6
4746.68
153(2)
0.71073
Triclinic
C140.58H84Ag17F28.74O26.42P6
4761.33
153(2)
0.71073
Triclinic
)
5434.46
153(2)
0.71073
Triclinic
ꢀ
ꢀ
ꢀ
P1
P1
P1
14.1252(9)
18.6012(12)
25.2137(17)
108.340(2)
95.386(2)
95.535(2)
6204.6(7)
1
15.5690(7)
16.7707(8)
34.0810(16)
93.4040(10)
100.3690(10)
94.8250(10)
8697.1(7)
15.5396(6)
16.7595(7)
34.0225(15)
93.8140(10)
100.1000(10)
94.9770(10)
8660.2(6)
b (Å)
c (Å)
a
(°)
b (°)
(°)
c
Volume (Å3)
Z
2
2
qcalcd (g cmÀ3
)
1.454
1.501
1.813
2.009
1.826
2.018
l
(mmÀ1
)
1.763
F(000)
2648
12,128
4560
4573
Crystal size (mm3)
Theta range
0.15 Â 0.10 Â 0.05
1.99 to 26.54°
140,641
0.15 Â 0.05 Â 0.05
2.068 to 26.556°
97,580
0.20 Â 0.20 Â 0.10
2.093 to 26.462°
181,843
0.20 Â 0.20 Â 0.10
2.10 to 26.45°
158,809
Reflections collected
Independent reflections
Completeness
Goof
25,598 [R(int) = 0.1134]
99.1%
24,429 [R(int) = 0.0690]
99.9%
35,809 [R(int) = 0.0328]
99.9%
0.875
35,611 [R(int) = 0.0353]
99.7%
0.840
0.721
0.846
Final R indices
R1a = 0.0741
R1a = 0.0529
R1a = 0.0573
wR2b = 0.1561
R1a = 0.0759
wR2b = 0.1702
3.596 and À2.950
R1a = 0.0537
wR2b = 0.1481
R1a = 0.0740
wR2b = 0.1602
3.352 and À2.876
b
b
[R > 2r
(I)]
wR2 = 0.1927
wR2 = 0.1242
R indices (all data)
R1a = 0.1243
R1a = 0.0946
wR2b = 0.2250
4.295 and À3.073
wR2b = 0.1461
1.369 and À1.443
Largest diff. peak and hole (e ÅÀ3
)
a
R1
wR2 = (
=
R
||Fo| À |Fc||/|Fo|.
b
R
[w(F2o À F2c)2]/
R
[w(F2o)2])0.5
.

60
S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
Fig. 1. (a) The Ag14 cluster core of complex 1. (b) Ball-and-stick representation of
the repeating unit of 1. All hydrogen atoms are omitted for clarity. Color code: pink,
silver; gray, carbon; orange, phosphorus; green, fluorine; red, oxygen; blue,
nitrogen. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Fig. 3. The 2D plane network viewed along c axis in the X-ray structure of 1,
showing the Ag14 cluster building blocks. All hydrogen atoms, CF3COOÀ and HCO3À
anions and DMF groups are omitted for clarity.
as the stacking of four Ag3 triangles with two additional Ag(I)
atoms each located at one end of the core structure (Fig. 1a). The
Ag14 cluster is bound and stabilized by eight ethynide ligands
(two C1„C2, two C21„C22, two C41„C42, and two C61„C62),
six CF3COOÀ and two HCOÀ3 anions, and four coordinating DMF sol-
vent molecules. The two Ag7 atoms at the end of the core each are
further bound to the P2 atom of a phosphine ligand, whose ethy-
nide moiety binds to another Ag14 cluster. This P2 atom is expected
to act as the capping ligand to prevent the uncontrolled and infi-
nite growth of the silver cluster. The Ag7–P2 bond length is found
to be 2.393(3) Å. It is worth noting that the carbonate groups found
in the X-ray structure of 1 are likely due to the fixation of carbon
dioxide from air, which is similar to previous results of synthesiz-
ing silver acetylides [1].
In addition to this Ag14 cluster, two symmetry equivalent Ag8
atoms are found to be each coordinated by two phosphine ligands
through Ag8–P3 (2.442(6) Å) and Ag8–P4 (2.455(5) Å) interactions
(Fig. 1b). Each Ag8 atom is coordinated by an additional HCO3À
anion through Ag8–O9 and Ag8–O10 interactions. Interestingly,
two symmetry equivalent Ag9 atoms each are connected to the
Ag14 cluster through the coordination with the C1„C2 ethynide
(Fig. 2b, along b axis) bonds extend the molecular structure to a
2D polymeric structure with high-nuclearity Ag14 clusters acting
as the building blocks (Fig. 3). Based on these results, the formula
of complex 1 can be determined to be [Ag18L8(CF3COO)6(HCO3)4
(DMF)4]n (the thermal ellipsoid plot of the X-ray structure of 1 is
depicted in Fig. S1).
3.3. Crystallographic studies of complex 2
Complex 2 crystallized in the monoclinic space group C2/c with
a = 48.046(4) Å, b = 14.1860(10) Å, c = 34.943(2) Å, b = 98.315(3)°,
V = 23,566(3) Å3, and Z = 4 (Table 1). Complex 2 contains a Ag16
cluster, which is located at the special position with a crystallo-
graphically required inversion center (Fig. 4). This Ag16 cluster is
similar to the Ag14 cluster represented in the structure of 1. It
can be viewed as the stacking of four Ag3 triangles with two Ag
(I) atoms each located at one end of the core and with two addi-
tional Ag(I) atoms each located at the flank of the core (Fig. 4a).
The Ag(I)–Ag(I) bond distances are in the range of 2.8867(7) to
3.2139(7) Å. This Ag16 cluster is bound and stabilized by eight
ethynide ligands (two C1@C2, two C21@C22, two C41@C42, and
two C61@C62), eight CF3COOÀ anions and four coordinating DMF
solvent molecules. The two Ag6 atoms at the end of the core each
are bound to the P1 atom of a phosphine ligand, whose ethynide
moiety binds to another Ag16 cluster, with a Ag6–P1 bond length
of 2.3923(19) Å. The two Ag8 atoms at the flank of the core each
are bound to the P2 atom of a phosphine ligand, whose ethynide
group through
p bond interactions (Ag9–C1 2.307(9) Å and Ag9–
C2 2.566(11) Å) and the oxygen atoms from one CF3COOÀ group
(O3) and one HCOÀ3 group (O12). The relatively long Ag9–Ag1
(3.3201(10) Å) and Ag9–Ag3 (3.2929(10) Å) bonds indicate the
presence of weak interactions between the Ag9 atom and the
Ag14 cluster. The Ag9 atom is further bound to the P1 atom of a
phosphine ligand, whose ethynide moiety binds to another Ag14
cluster, with an Ag9–P1 bond length of 2.383(3) Å. Importantly,
the interactions of Ag9–P1 (Fig. 2a, along a axis) and Ag7–P2
Fig. 2. (a) The 1D chain along a axis in the X-ray structure of 1. (b) The 1D chain along b axis in the X-ray structure of 1. All hydrogen atoms, CF3COOÀ and HCO3À anions and
DMF groups are omitted for clarity.

S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
61
Fig. 4. (a) The Ag16 cluster core of complex 2. (b) Ball-and-stick representation of
the repeating unit of 2. All hydrogen atoms are omitted for clarity. Color code: pink,
silver; gray, carbon; orange, phosphorus; green, fluorine; red, oxygen; blue,
nitrogen. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Fig. 6. The 2D plane network viewed along a axis in the X-ray structure of 2,
showing the Ag16 cluster building blocks. All hydrogen atoms, CF3COOÀ anions and
DMF groups are omitted for clarity.
moiety also binds to another Ag16 cluster, with a Ag8–P2 bond
length of 2.4186(17) Å. As a consequence, these phosphine ligands
are found to act as capping ligands to confine the silver cluster to a
certain size.
cluster is bound and stabilized by six ethynide ligands (C1„C2,
C21„C22, C41„C42, C61„C62, C81„C82 and C101„C102), nine
CF3COOÀ and two HCOÀ3 anions. The four Ag(I) atoms located at the
end of the Ag15 cluster core each are bound to a phosphine ligand
with Ag12–P3 bond length at 2.3869(19) Å, Ag13–P4 bond length
at 2.3958(19) Å, Ag14–P1 bond length at 2.3888(17) Å, and
Ag15–P2 bond length at 2.3972(18) Å. All these phosphine ligands
have their ethynide moieties bound to other Ag15 clusters. Similar
to complex 1, the carbonate groups found in the X-ray structure of
3 are likely due to the fixation of carbon dioxide from air during the
synthesis. For the two carbonate groups, one bridges three Ag(I)
atoms, while the other bridges two Ag(I) atoms.
In addition to the Ag15 cluster, two Ag(I) atoms, Ag16 and Ag17,
are found in the X-ray structure of 3 and play significant roles in
constructing the polymeric structure (Fig. 7b). For Ag16, it is con-
nected to the Ag15 cluster through the binding with three CF3COOÀ
anions (O4, O6 and O7), and is further bound to the P5 atom of a
phosphine ligand with a Ag16–P5 bond length at 2.3488(18) Å.
For Ag17, it is connected to the Ag15 cluster through the binding
with two CF3COOÀ anions (O14 and O18), and is further bound
to the P6 atom of a phosphine ligand with a Ag17–P6 bond length
at 2.342(2) Å. The formula of complex 3 can be then determined to
be [Ag17L6(CF3COO)9(HCO3)2]n (the thermal ellipsoid plot of the X-
ray structure of 3 is depicted in Fig. S3).
In addition to the Ag16 cluster, two symmetry equivalent Ag2
units were found to be flanked by two phosphine ligands of P3
and P4 in the X-ray structure of 2 (Fig. 4b). The Ag9–P3 bond length
is 2.354(2) Å, while the Ag10–P4 bond length is 2.358(2) Å. These
two Ag(I) atoms are linked together by two CF3COOÀ anions. One
CF3COOÀ anion bridges Ag9 and Ag10 through two O atoms, while
the other CF3COOÀ anion bridges the two Ag(I) atoms through one
O atom. Ag9 is coordinated by an additional DMF solvent molecule.
These results give complex 2 the formula of [Ag20L8(CF3COO)12(-
DMF)6]n (the thermal ellipsoid plot of the X-ray structure of 2 is
depicted in Fig. S2). Similar to complex 1, in the structure of 2,
the interactions of Ag8–P2 (Fig. 5a, along b axis) and Ag6–P1
(Fig. 5b, along c axis) bonds extend the molecular structure to a
2D polymeric structure with high-nuclearity Ag16 clusters acting
as the building blocks (Fig. 6).
3.4. Crystallographic studies of complexes 3 and 4
ꢀ
Complex 3 crystallized in the triclinic space group P1 with
a = 15.5690(7) Å, b = 16.7707(8) Å, c = 34.0810(16) Å,
a = 93.4040
= 94.8250(10)°, V = 8697.1(7) Å3, and
Significantly, the many bridging interactions of Ag(I)–P-C6H4-4-
C„C–Ag(I) in the structure of 3 extend the molecular structure to a
3D polymeric structure with 1D chains (Fig. 8), 2D planes (Fig. 9)
and 3D structures (Fig. 10) presented. The use of a Ag15 cluster as
the building block for the assembly of such a 3D organometallic
polymer is unprecedented.
(10)°, b = 100.3690(10)°,
c
Z = 2 (Table 1). Complex 3 contains a Ag15 cluster, which is located
at the general position without any crystallographically required
symmetry elements. The Ag(I)–Ag(I) bond distances are in the
range of 2.8598(8) to 3.3436(7) Å. The Ag15 cluster can be viewed
as two Ag7 caps linked by a central Ag6 atom (Fig. 7a). The Ag15
Fig. 5. (a) The 1D chain along b axis in the X-ray structure of 2. (b) The 1D chain along c axis in the X-ray structure of 2. All hydrogen atoms, CF3COOÀ anions and DMF groups
are omitted for clarity.

62
S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
Fig. 9. The 2D plane network viewed along a axis in the X-ray structure of 3,
showing the Ag15 cluster building blocks. All hydrogen atoms are omitted for
clarity.
Fig. 7. (a) The Ag15 cluster core of complex 3. (b) Ball-and-stick representation of
the repeating unit of 3. All hydrogen atoms are omitted for clarity. Color code: pink,
silver; gray, carbon; orange, phosphorus; green, fluorine; red, oxygen. (For
interpretation of the references to colour in this figure legend, the reader is
referred to the web version of this article.)
The structure of complex 4 is almost identical to that of 3. Com-
ꢀ
plex 4 crystallized in the triclinic space group P1 with a = 15.5396
(6) Å, b = 16.7595(7) Å, c = 34.0225(15) Å,
a = 93.8140(10)°,
b = 100.1000(10)°,
c
= 94.9770(10)°, V = 8660.2(6) Å3, and Z = 2
(Table 1). In the structure of 4, the carbonate group that bridges
three Ag(I) atoms is partially replaced by a CF3COOÀ anion. Free
structural refinement gave a ratio of 58% CF3COOÀ and 42% HCO3À
anions at this position. Except this difference, the structures of
complexes 3 and 4 are the same. The formula of complex 4 is
[Ag17L6(CF3COO)9.58(HCO3)1.42]n (the thermal ellipsoid plot of the
X-ray structure of 4 is depicted in Fig. S4). It is necessary to note
that due to their structural similarities, it is possible that the bulk
sample we isolated may be a mixture of 3 and 4.
Fig. 10. The 3D framework in the X-ray structure of 3, which is composed by the
stacking of 2D planes. All hydrogen atoms are omitted for clarity.
Fig. 8. (a) The 1D chain along a axis in the X-ray structure of 3. (b) The 1D chain along b axis in the X-ray structure of 3. All hydrogen atoms are omitted for clarity.

S. Zhang et al. / Inorganica Chimica Acta 461 (2017) 57–63
63
[11] T.L. Zhang, Y.J. Hu, J.X. Kong, X.G. Meng, X.M. Dai, H.B. Song, CrystEngComm 12
(2010) 3027–3032.
4. Conclusion
[12] Y. Jiang, Y.T. Wang, Z.G. Ma, Z.H. Li, Q.H. Wei, G.N. Chen, Organometallics 32
(2013) 4919–4926.
[13] U. Halbes-Letinois, J.M. Weibel, P. Pale, Chem. Soc. Rev. 36 (2007) 759–769.
[14] J.M. Weibel, A. Blanc, P. Pale, Chem. Rev. 108 (2008) 3149–3173.
[15] D. Tejedor, S. López-Tosco, F. Cruz-Acosta, G. Méndez-Abt, F. García-Tellado,
Angew. Chem. Int. Ed. 48 (2009) 2090–2098.
In conclusion, we designed and synthesized (4-ethynylphenyl)
diphenyl phosphine. Its deprotonation gives the desired bifunc-
tional ligand L = Ph2P-C6H4-4-C„CÀ bearing both phenylethynide
and phosphine binding sites for Ag(I). With the use of this ligand,
we were able to synthesize and structurally characterize four silver
acetylides 1–4. Complexes 1 and 2 have 2D polymeric structures,
while complexes 3 and 4 have 3D structures. Ligand L plays signif-
icant roles in constructing these polymeric silver acetylides: (1)
[16] Y. Unoh, K. Hirano, T. Satoh, M. Miura, Angew. Chem. Int. Ed. 52 (2013) 12975–
12979.
[17] J. Ke, C. He, H.Y. Liu, M.J. Li, A.W. Lei, Chem. Commun. 49 (2013) 7549–7551.
[18] Y. Yamamoto, Chem. Rev. 108 (2008) 3199–3222.
[19] G.C. Fang, X.H. Bi, Chem. Soc. Rev. 44 (2015) 8124–8173.
[20] J.Q. Liu, Z.X. Fang, Q. Zhang, Q. Liu, X.H. Bi, Angew. Chem. Int. Ed. 52 (2013)
6953–6957.
[21] M. Gao, C. He, H.Y. Chen, R.P. Bai, B. Cheng, A.W. Lei, Angew. Chem. Int. Ed. 52
(2013) 6958–6961.
[22] J.Q. Liu, Z.H. Liu, N.N. Wu, P.Q. Liao, X.H. Bi, Chem. Eur. J. 20 (2014) 2154–2158.
[23] J. Nishijo, O. Oishi, K. Judai, N. Nishi, Chem. Mater. 19 (2007) 4627–4629.
[24] B.K. Teo, Y.H. Xu, B.Y. Zhong, Y.K. He, H.Y. Chen, W. Qian, Y.J. Deng, Y.H. Zou,
Inorg. Chem. 40 (2001) 6794–6801.
[25] H.S. Lo, E.C.C. Cheng, H.L. Xu, W.H. Lam, N.Y. Zhu, V.K.M. Au, V.W.W. Yam, J.
Organomet. Chem. 812 (2016) 43–50.
[26] Z.Y. Zhang, Y. Yang, H.Y. Sun, R. Cao, Inorg. Chim. Acta 434 (2015) 158–171.
[27] R. Zhang, Z.N. Liang, A.L. Han, H.T. Wu, P.W. Du, W.Z. Lai, R. Cao,
CrystEngComm 16 (2014) 5531–5542.
The ethynide moiety binds with Ag(I) atoms through both
r and
p
bonding interactions and is crucial for the formation of high-
nuclearity silver clusters. (2) The phosphine ligand acts as capping
ligands to confine the silver cluster to a certain size by preventing
its uncontrolled and infinite growth. (3) The bridging Ag(I)–P-
C6H4-4-C„C–Ag(I) linkage extends molecular structures to poly-
meric structures. Complexes 1–4 represent unprecedented silver
acetylide frameworks with high-nuclearity silver cluster building
blocks.
[28] T.C.W. Mak, X.L. Zhao, Q.M. Wang, G.C. Guo, Coord. Chem. Rev. 251 (2007)
2311–2333.
Notes
[29] Q.M. Wang, Y.M. Lin, K.G. Liu, Acc. Chem. Res. 48 (2015) 1570–1579.
[30] L. Zhao, W.Y. Wong, T.C.W. Mak, Chem. Eur. J. 12 (2006) 4865–4872.
[31] L. Zhao, T.C.W. Mak, J. Am. Chem. Soc. 127 (2005) 14966–14967.
[32] L. Zhao, T.C.W. Mak, J. Am. Chem. Soc. 126 (2004) 6852–6853.
[33] Y.P. Xie, T.C.W. Mak, J. Am. Chem. Soc. 133 (2011) 3760–3763.
[34] L. Zhao, X.L. Zhao, T.C.W. Mak, Chem. Eur. J. 13 (2007) 5927–5936.
[35] L. Zhao, C.Q. Wan, J. Han, X.D. Chen, T.C.W. Mak, Chem. Eur. J. 14 (2008)
10437–10444.
[36] R. Zhang, X. Hao, X.M. Li, Z.Y. Zhou, J.L. Sun, R. Cao, Cryst. Growth Des. 15
(2015) 2505–2513.
[37] Z.F. Zhang, B. Li, X.G. Meng, X.B. Yin, T.L. Zhang, Dalton Trans. 42 (2013) 4306–
4312.
[38] S.C.K. Hau, T.C.W. Mak, Cryst. Growth Des. 14 (2014) 3567–3575.
[39] S.C.K. Hau, T.C.W. Mak, Chem. Eur. J. 19 (2013) 5387–5400.
[40] I.O. Koshevoy, A.J. Karttunen, J.R. Shakirova, A.S. Melnikov, M. Haukka, S.P.
Tunik, T.A. Pakkanen, Angew. Chem. Int. Ed. 49 (2010) 8864–8866.
[41] L.J. Xu, J.Y. Wang, L.Y. Zhang, L.X. Shi, Z.N. Chen, Organometallics 32 (2013)
5402–5408.
The authors declare no competing financial interest.
Acknowledgments
We are grateful for support from the ‘‘Thousand Talents
Program” of China, the National Natural Science Foundation of
China (Grant No. 21101170 and 21573139), the Fundamental
Research Funds for the Central Universities, and the Research
Funds of Shaanxi Normal University.
Appendix A. Supplementary data
[42] I.O. Koshevoy, Y.C. Lin, A.J. Karttunen, M. Haukka, P.T. Chou, S.P. Tunik, T.A.
Pakkanen, Chem. Commun. (2009) 2860–2862.
[43] I.O. Koshevoy, C.L. Lin, A.J. Karttunen, J. Jänis, M. Haukka, S.P. Tunik, P.T. Chou,
T.A. Pakkanen, Inorg. Chem. 50 (2011) 2395–2403.
[44] I.O. Koshevoy, A.J. Karttunen, S.P. Tunik, M. Haukka, S.I. Selivanov, A.S.
Melnikov, P.Y. Serdobintsev, T.A. Pakkanen, Organometallics 28 (2009)
1369–1376.
[45] I.S. Krytchankou, D.V. Krupenya, A.J. Karttunen, S.P. Tunik, T.A. Pakkanen, P.T.
Chou, I.O. Koshevoy, Dalton Trans. 43 (2014) 3383–3394.
[46] T.C.W. Mak, L. Zhao, Chem. Asian J. 2 (2007) 456–467.
[47] T. Hu, L. Zhao, T.C.W. Mak, Organometallics 31 (2012) 7539–7547.
[48] T.L. Zhang, J.X. Kong, Y.J. Hu, X.G. Meng, H.B. Yin, D.S. Hu, C.P. Ji, Inorg. Chem.
47 (2008) 3144–3149.
[49] L. Zhao, T.C.W. Mak, Inorg. Chem. 48 (2009) 6480–6489.
[50] Y. Zhao, P. Zhang, B. Li, X.G. Meng, T.L. Zhang, Inorg. Chem. 50 (2011) 9097–
9105.
[51] N.T. Lucas, M.P. Cifuentes, L.T. Nguyen, M.G. Humphrey, J. Cluster Sci. 12
(2001) 201–221.
[52] A.X.S. Brüker, APEX2 v2009, Madison, WI, 2009.
[53] G.M. Sheldrick, SADABS, 2008/1, University of Göttingen, Göttingen, Germany,
2008.
Scheme S1; Figures S1–S5; Crystallographic data as CIF for com-
plexes 1–4. Supplementary data associated with this article can be
found, in the online version, at http://dx.doi.org/10.1016/j.ica.
2017.01.030.
References
[1] S.D. Bian, J.H. Jia, Q.M. Wang, J. Am. Chem. Soc. 131 (2009) 3422–3423.
[2] J. Qiao, K. Shi, Q.M. Wang, Angew. Chem. Int. Ed. 49 (2010) 1765–1767.
[3] Y.P. Xie, T.C.W. Mak, Angew. Chem. Int. Ed. 51 (2012) 8783–8786.
[4] S.C.K. Hau, P.S. Cheng, T.C.W. Mak, J. Am. Chem. Soc. 134 (2012) 2922–2925.
[5] F. Gruber, M. Jansen, Angew. Chem. Int. Ed. 49 (2010) 4924–4926.
[6] X. Liu, Q.L. Yi, Y.Z. Han, Z.N. Liang, C.H. Shen, Z.Y. Zhou, J.L. Sun, Y.Z. Li, W.B. Du,
R. Cao, Angew. Chem. Int. Ed. 54 (2015) 1846–1850.
[7] V.W.W. Yam, K.K.W. Lo, K.M.C. Wong, J. Organomet. Chem. 578 (1999) 3–30.
[8] M.C. Blanco, J. Cámara, M.C. Gimeno, A. Laguna, S.L. James, M.C. Lagunas, M.D.
Villacampa, Angew. Chem. Int. Ed. 51 (2012) 9777–9779.
[9] I.O. Koshevoy, A.J. Karttunen, I.S. Kritchenkou, D.V. Krupenya, S.I. Selivanov, A.
S. Melnikov, S.P. Tunik, M. Haukka, T.A. Pakkanen, Inorg. Chem. 52 (2013)
3663–3673.
[10] R. Zhang, C.Y. Zhao, X.M. Li, Z.Y. Zhang, X.C. Ai, H. Chen, R. Cao, Dalton Trans. 45
(2016) 12772–12778.
[54] G.M. Sheldrick, Acta Cryst. A46 (1990) 467–473.
[55] G.M. Sheldrick, Acta Cryst. A64 (2008) 112–122.
[56] H. Schmidbaur, A. Schier, Angew. Chem. Int. Ed. 54 (2015) 746–784.