Assembly of BF4-, PF6-, ClO4- and F- with trinuclear copper(i) acetylide complexes bearing amide groups: structural diversity, photophysics and anion binding properties

Article abstract of DOI:10.1039/c5ra18534c

Trinuclear copper(i) acetylide complexes 1·BF₄-4·BF₄, 1·PF₆, 1·ClO₄ and 4·F have been synthesized and characterized. Five kinds of discrete or polymeric structures could be found in their crystal structures. Among them, complexes 1·BF₄, 1·PF₆, and 1·ClO₄ form zigzag one-dimensional (1D) anion coordination polymers (ACPs) using anions as nodes and cations 1 as ligands. For complex 2·BF₄, hydrogen bonds between adjacent amide groups afford the zigzag 1D polymeric chains, which are supported by the interaction between dppms and anions. A 1D infinite meso-helical hydrogen bonding polymeric chain with a counter anion bound in each cation can be observed in complex 3·BF₄. Complex 4·BF₄ is unable to form polymeric chains, while complex 4·F that exhibits similar structure with 4·BF₄ could construct infinite 1D polymer via hydrogen bonds between amide groups. The photophysical properties of copper(i) acetylide complexes have been studied. They show luminescence both in the solid state and DMSO solution at 298 K. The anion binding abilities of complexes 1·BF₄-4·BF₄ in DMSO have also been studied by using ¹H NMR and UV-vis titration experiments. Their dramatic color change towards F^- in DMSO enables naked eye detection of F^-.

Full text of DOI:10.1039/c5ra18534c

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DOI: 10.1039/C5RA18534C
ARTICLE
Assembly of BF4 , PF6 , ClO4 and F with trinuclear
copper(I) acetylide complexes bearing amide groups:
Structural diversity, photophysics and anion binding
properties



Cite this: DOI: 10.1039/x0xx00000x
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
Hua-Yun Shi, Yong-Liang Huang, Jia-Kai Sun, Ji-Jun Jiang, Zhi-Xing Luo, Hui-
Tao Ling, Chi-Keung Lam and Hsiu-Yi Chao*
www.rsc.org/
Trinuclear copper(I) acetylide complexes 1∙BF4
synthesized and characterized. Five kinds of discrete or polymeric structures could be found in
their crystal structures. Among them, complexes 1∙BF4 1∙PF6, and 1∙ClO4 form zigzag one-
dimensional (1D) anion coordination polymers (ACPs) using anions as nodes and cations as
4∙BF4, 1∙PF6, 1∙ClO4 and 4∙F have been
,
1
ligands. For complex 2∙BF4, hydrogen bonds between adjacent amide groups afford the zigzag
1D polymeric chains, which are supported by the interaction between dppms and anions. A 1D
infinite meso-helical hydrogen bonding polymeric chain with a counter anion bound in each
cation can be observed in complex 3∙BF4. Complex 4∙BF4 is unable to form polymeric chains,
while complex 4∙F that exhibits similar structure with 4∙BF4 could construct infinite 1D
polymer via hydrogen bonds between amide groups. The photophysical properties of copper(I)
acetylide complexes have been studied. They show luminescence both in the solid state and
DMSO solution at 298 K. The anion binding abilities of complexes 1∙BF44∙BF4 in DMSO
1
have also been studied by using H NMR and UV-vis titration experiments. Their dramatic
color change towards F in DMSO enables the naked eye detection of F.
polymer (ACPs) and yet to be explored17, 18, 21, 27, 28, 37. In contrast to
the well-developed metal coordination polymers (CPs), in which
Introduction
metals with specific geometrical preference are employed as nodes,
the construction of ACPs is imposed with more difficulties due to the
weaker bonding strength of hydrogen bond and higher complexity of
Anion coordination chemistry has attracted growing interest and
developed rapidly in recent years, owing to the chemical, biological
and environmental importance of anions.18 In 1968, Park and
Simmons9 reported the first hydrogen bonding based halide sensor,
which was regarded as the herald of the anion coordination
chemistry. The concept of anion coordination was firstly proposed
by Lehn10 in 1978, which exhibited remarkable similarities and
differences with traditional metal coordination chemistry. Compared
with metal coordination, anion coordination is formed via the weak
interactions (mainly hydrogen bond) between anions and ligands,
rather than the covalent bond between ligands and metals. Owing to
the diverse range of sizes, geometries, basicities and hydrogen-
bonding modes of different anions, complexation of anions with the
receptor molecules is highly challenging and requires delicate
designs of host molecules.11 The groups of Beer,1215 Gale,1619
Steed,2023 Custelcean,2427 Wu2832 and others3336 have reported
novel anion-based architectures and studied their anion-binding
modes, anion separation properties and fluorescence properties.
Notably, supramolecular architectures with anions as the
coordination nodes and organic ligand or metal complexes as linkers,
bearing infinite polymeric nature, are defined as anion coordination
anions.11 ACPs not only have potential applications as sensors28, 37 or
37
optical materials,32,
but also exhibit structural and topological
novelty with diverse and interesting structural motifs. The simplest
type of ACPs, 1D-ACPs, which usually bear properties3839 such as
anion exchange, gelation, and nanocrystal synthetic template, exhibit
diverse polymeric architectures38 such as linear, zigzag, helical, and
ladder. The key factors that could affect the structures of ACPs are
the building blocks: metal, ligands, and counter anions.28, 40 Previous
works included sulfate directed double strand helical self-assembly
of chiral bicyclic guanidinium tetramers firstly reported by
Mendoza’s group,41 1D linear ACPs with acetate or terephthalate
carboxylate anions and a bis-bisurea ligand based on a biphenyl
backbone published by Gale’s group,17 chloride bridged
supramolecular polymeric network with BF2 complexes of acyclic
dipyrrolyldiketone constructed by Maeda’s group,37 and a series of
ACPs with a bis-bisurea ligand that bears a rigid naphthylene spacer
as a linker between two anions, including SO42, AcO, p-

[COOC6H4COO]2 , Cl, and Br, studied by Wu’s group.28
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DOI: 10.1039/C5RA18534C
Scheme 1 Synthetic route for trinuclear copper(I) acetylide complexes 1∙BF44∙BF4, 1∙PF6, and 1∙ClO4.
dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-NO2)2]X (X
=
PF6
To date, however, anion-templated polymeric assemblies are very
(1∙PF6) and ClO4 (1∙ClO4)), and [Cu3(-dppm)3(3-1-C≡CC6H4-4-
NHC(O)C6H4-4-OCH3)2]F (4∙F). The X-ray crystal structures of
anion complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F were
analyzed in detail to investigate the influence of anion as well as R
substitutents on polymeric architectural diversity. The photophysics
of acetylide ligands and complexes as well as anion binding
properties of complexes 1∙BF44∙BF4 in DMSO solution were also
studied.
rare, and most of well-studied structures employed organic receptors
as linkers.40
In the past decades, metal complexes have been frequently used
as anion sensors due to their properties like redox and luminescence,
which could provide various accesses of sensing.42 Trinuclear
copper(I) acetylide complexes have attracted considerable attention
because of their rich photophysical and photochemical
properties.4347 The first trinuclear copper(I) complex with two
capped µ3-ƞ1-acetylides with short Cu(I)∙∙∙Cu(I) distances, [Cu3(µ-
dppm)3(µ3-ƞ1-C≡CPh)2](BF4) (dppm
=
bis(diphenylphosphino)
Results and discussion
methane), was reported by Gimeno and co-workers48 in 1991.
Subsequently, a systematical investigation on the photophysical
properties of bicapped trinuclear copper(I) acetylide complexes was
performed by Yam’s group.4347 Our group49 also reported a series of
trinuclear copper(I) acetylide complexes bearing carbonyl moiety.
However, research on trinuclear copper(I) acetylide complexes as
anion sensors is still blank.
Syntheses and characterization
The synthetic route of trinuclear copper(I) acetylide complexes
1∙BF44∙BF4, 1∙PF6 and 1∙ClO4 is summarized in scheme 1.
Acetylide ligands L1L4 were obtained by using similar methods
reported in our previous paper.59 The reactions of dinuclear
Neutral NH or cationic (NH)+ hydrogen bond donor is a key
component of anion receptors, and amide-based ligands belong to
the neutral-type anion receptors.50 It is interesting to note that anion
binding by proteins is mostly achieved by way of neutral amide
functional groups.51 The highly accessible hydrogen-bond donor
with directional hydrogen-bonding being involved for the host–guest
interaction11 provides amide receptors with a differentiating power to
screen anions of different geometries or hydrogen bonding
requirements.52 These features, combined with their simple
structures and easy modification by organic synthesis, make amide
groups commonly be employed in the design of anion sensors. The
supporting interactions between appropriately placed backbone CH



complexes [Cu2(µ-dppm)2(CH3CN)4](X)2 (X = BF4 , PF6 , or ClO4 )
with L1L4 in the molar ration of 3:4 in degassed acetonitrile in the
presence of triethylamine at 298 K gave trinuclear copper(I)
acetylide complexes 1∙BF44∙BF4, 1∙PF6 and 1∙ClO4, respectively.
All copper(I) acetylide complexes 1∙BF44∙BF4, 1∙PF6 and 1∙ClO4
are air-stable in the solid state at 298 K and can be well dissolved in
CH2Cl2, CH3CN, THF and DMSO. They gave satisfactory elemental
analysis and were all characterized by IR, ESI-MS and NMR.
The IR spectra of the trinuclear copper(I) acetylide complexes
1∙BF44∙BF4, 1∙PF6, and 1∙ClO4 contain three bands at ca.
33683399, 21702270 and ca. 16561677 cm1, which could be
ascribed to ν(NH), ν(C≡C) and ν(C=O) of acetylide ligands,
respectively. In the 1H NMR spectra, complexes 1∙BF44∙BF4, 1∙PF6
and 1∙ClO4 in CD3CN display a singlet at  8.909.30 ppm, which
are assigned as the resonances of the amide NH of the acetylide
ligand. The chemical shifts of these peaks are in the following order:
1∙BF4 > 2∙BF4 > 3∙BF4 > 4∙BF4, which is in line with the decreasing
of the electron-withdrawing ability of substituent R (R = NO2 (1),
CF3 (2), H (3), OCH3 (4)) on the acetylide ligand. In addition, the
chemical shifts at δ 6.648.54 ppm are attributed to the resonances
of the protons on the aromatic rings of the dppm and acetylide
ligands. A singlet at ca.  3.30 ppm is ascribed as the resonance of
the protons of CH2 moieties on dppm ligands. The 31P NMR spectra
of the complexes 1∙BF44∙BF4, 1∙PF6 and 1∙ClO4 in CD3CN show a
singlet at ca. δ 6.00 ppm. While complex 1∙PF6 in CD3CN shows
an additional quintet at ca. δ 144.65 ppm, which can be ascribed to
protons and anions are essential as well and enhance the anion-
5356
binding affinity.22,
In some cases, CH sites associate with
5356
anions without the supporting NH.
Theoretical studies also
support the interactions between CH units and anions.5758
Aromatic CHs involve in the interaction with anions most
frequently, while Maeda’s group37 reported the first example of
anion recognition assisted by nonaromatic CH∙∙∙anion interactions.
Transition metal complexes with amide NH hydrogen bond
donor as anion-binding sites are our group’s long-term interest.59
Complexes with different R substituents exhibit varied affinities
toward anions compared with their analogues,59 we therefore
envisaged that the acidity of amide groups could influence their
coordination patterns and selective crystallization to anions. In this
work, we have synthesized and characterized a series of trinuclear
copper(I) acetylide complexes, [Cu3(-dppm)3(3-1-C≡CC6H4-4-
NHC(O)C6H4-4-R)2]BF4 (R = NO2 (1∙BF4), H (3∙BF4) and OCH3

the counter anion PF6 . As for 19F NMR spectra in CD3CN,
(4∙BF4)),
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-
complexes 1∙BF44∙BF4 display two singlet at ca. δ 151.65 and
151.70 ppm with a proportion of 1:4 in peak area, which could be
CF3)(2-1-C≡CC6H4-4-NHC(O)C6H4-4-CF3)]BF4 (2∙BF4), [Cu3(-
2 | J. Name., 2012, 00, 1-3
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
ascribed to BF4 (the natural abundance of 10B to 11B is 1/4).
Complex 1∙PF6 shows a doublet at δ 73.53 ppm with a coupling
constant of 700 Hz, owing to 31P 19F coupling. Complex 4∙F was
obtained by addition of excess amount of F into 4∙BF4 in CH3CN.
The IR, ESI-MS, 1H NMR and 31P NMR spectra of 4∙F are similar to
those of 4∙BF4.
flap. One of them folds toward one of the faces of the Cu3 triangles,
while the other two fold away from it. The CuP distances are in the
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range of 2.2549(12)2.2948(11) Å, which resemble those in
DOI: 10.1039/C5RA18534C
analogous trinuclear copper(I) acetylide complexes.4349 Two C≡C
groups bridge the Cu3 planar through an asymmetric μ3-η1 bridging
mode with different CuC distances in the range of
2.077(4)2.411(4) Å (for 2 exclusively, one of the C≡C group
employs an asymmetric μ2-η1 bridging mode). It is noted that one of
the three CuC distances is relatively longer than the other two
CuC distances. The bond angles between the acetylide ligands and
copper atoms in cation 1 are in the range of 123.0(4)°159.1(4)°.
The C≡C bond distances are 1.197(6)and 1.203(6) Å, respectively,
characteristic of typical metal acetylide
σ
bonding.61 The
conformations of two acetylide motifs attached on Cu3 are not
exactly identical to each other, which could be deduced from their
different torsion angles. In the first acetylide motif, the torsion
angles of C(5)C(6)N(1)C(9) and C(15)C(10)C(9)N(1) are
4.00° and 24.41°, respectively. In the other motif, the torsion angles
of C(22)C(21)N(3)C(24) and C(26)C(25)C(24)N(3) are
16.37° and 30.22°, respectively. Dihedral angle between plane
O(1)C(9)N(1) and plane O(4)C(24)N(3) is 27.48°, suggesting
two amide moieties point to different direction. The C=O distances
for 1 are 1.202(6) and 1.214(7) Å, which resemble typical carbonyl
groups in analogues amide receptors.50, 59
Table 1 Selected bond lengths (Å) and angles (°) for 1∙PF6.
Cu(1)∙∙∙Cu(2)
Cu(1)∙∙∙Cu(3)
Cu(2)∙∙∙Cu(3)
Cu(1)C(1)
Cu(2)C(1)
Cu(3)C(1)
Cu(1)C(16)
Cu(2)C(16)
Cu(3)C(16)
Cu(1)P(4)
Cu(1)P(5)
Cu(2)P(2)
Cu(2)P(3)
Cu(3)P(1)
Cu(3)P(6)
C(1)C(2)
2.5653(8)
2.7672(8)
2.5374(8)
2.175(4)
2.077(4)
2.411(4)
2.310(4)
2.114(4)
2.135(4)
2.2914(12)
2.2616(13)
2.2824(11)
2.2832(11)
2.2948(11)
2.2549(12)
1.197(6)
1.203(6)
1.214(7)
1.202(6)
1.218(7)
1.210(7)
1.221(7)
1.223(7)
124.3(4)
159.1(4)
123.0(4)
123.5(3)
150.0(4)
132.8(4)
74.18(14)
74.02(13)
68.39(12)
70.71(12)
76.89(13)
73.33(14)
Fig. 1 The crystal structures of cations (a) 1, (b) 2, (c) 3, and (d) 4
with the atomic numbering scheme (phenyl rings on dppm and
hydrogen atoms are omitted for clarity). Thermal ellipsoids are
shown at 30 % probability level.
X-ray crystal structure
Structures of cations 14
The crystals of complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F were
obtained through the diffusion of ether into corresponding solution
C(16)C(17)
(1∙BF4 and 2∙BF4 in CH3CN, 1∙PF6 and 1∙ClO4 in CH2Cl2, 3∙BF4 C(9)O(1)
and 4∙F in CH3OH and 4∙BF4 in acetone and methanol mixed
solution). Their crystallographic data as well as selected bond
distances and angles are listed in Table S1S6 (ESI†) and Table 1.
The PXRD patterns (Fig. S1, ESI†) revealed the phase purity of
complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F and indicated that
the complexes were stable in air at room temperature. The
perspective drawings of cations 14 are shown in Figure 1. Since the
structures of cations 14 are similiar, 1∙PF6 is selected as an example
for discussion. It crystallizes in the orthorhombic space group Pccn.
The structure of the complex cation 1 is similar to those of previous
reported [Cu3(-dppm)3(3-1-C≡CR′)2]+ analogues,4349 which
consists of an approximately isosceles triangle of copper atoms with
a dppm ligand bridging each edge to form a roughly planar [Cu3P6]
core. The distances between two copper atoms are in the range of
2.5374(8)2.7672(8) Å, which are shorter than the sum of van der
Waals radii for copper atoms (2.8 Å).60 This observation suggests the
presence of weak Cu∙∙∙Cu interactions. Three Cu2P2C rings adopt
envelope conformations with the methylene carbon atoms on the
C(24)O(4)
N(2)O(2)
N(2)O(3)
N(4)O(5)
N(4)O(6)
Cu(1)C(1)C(2)
Cu(2)C(1)C(2)
Cu(3)C(1)C(2)
Cu(1)C(16)C(17)
Cu(2)C(16)C(17)
Cu(3)C(16)C(17)
Cu(1)C(1)Cu(2)
Cu(1)C(1)Cu(3)
Cu(2)C(1)Cu(3)
Cu(1)C(16)Cu(2)
Cu(1)C(16)Cu(3)
Cu(2)C(16)Cu(3)
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interactions (Fig. 3(b) and 4(b). However, their configurations are
Structures of anion complexes
(1) Complexes with NO2 group
affected by the counter anions with varied size, shape and basicity.



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In contrast to octahedral PF6 , BF4 and ClO4 with tetrahedral
geometry in this system are three-coordinaDteOdI.: 1O0.n10ly39o/Cn5eRAa1to8m534iCn
each anion is able to form hydrogen bond with two ligands in
In complex 1∙PF6, hydrogen bonds are formed between

hexafluorophosphate (PF6 ) and amide NHs as well as
hexafluorophosphate anion and aromatic CHs in acetylide ligands adjacent cations 1. The hydrogen bond distances (N∙∙∙F) and angles
(Fig. 2(b). Hexafluorophosphate anion in 1∙PF6 is five-coordinated. of NH∙∙∙F in 1∙BF4 are in the range of 2.97733.2826 Å and
Each hexafluorophosphate anion is surrounded by two amide clefts
of two trinuclear copper(I) complexes and coordinated mainly by
two hydrogen bonds from amide groups, which were supplemented
by three additional CH∙∙∙F interactions. The hydrogen bond
distances (N∙∙∙F) and angles of NH∙∙∙F in 1∙PF6 are in the range of
3.13363.2179 Å and 142°154°, respectively (Table 2). The
supporting interactions CH∙∙∙F are weaker than NH∙∙∙F with longer
bond distances (C∙∙∙F, 3.31523.3478 Å) and similar CH∙∙∙F angles
(146°155°). The dihedral angle of adjacent Cu3 plane (plane
Cu(1)Cu(2)Cu(3) and plane Cu(1′)Cu(2′)Cu(3′)) is 51.16°. Two
adjacent “Cu3 cluster ligands” around hexafluorophosphate anion are
in a bended arrangement, with an dihedral angle between plane
N(1)C(9)O(1) and plane N(3′)C(24′)O(4′) being 25.20°. As a
138°153°, respectively (Table 2). While the hydrogen bond
distances (N∙∙∙O) and angles of NH∙∙∙O in 1∙ClO4 are in the range
of 3.075(9)3.291(11) Å and 138°155°, respectively (Table 2). The
configuration of 1∙BF4 is supplemented by an additional CH∙∙∙F
bond (C∙∙∙F distance 3.3395 Å; CH∙∙∙F angle 152°), and 1∙ClO4 by
a CH∙∙∙O bond (C∙∙∙O distance 3.342(12) Å; CH∙∙∙O angle 152°).

The stronger basicity of BF4 results in the shorter hydrogen bond
distances in 1∙BF4 when compared with their counterparts in 1∙ClO4.
The dihedral angle of adjacent Cu3 plane (plane Cu(1)Cu(2)Cu(3)
and plane Cu(1′)Cu(2′)Cu(3′)) is 46.89° for 1∙BF4, and 47.59° for
1∙ClO4. Similar to the two unparalleled ligands in 1∙PF6, the dihedral
angle
of
plane
N(120)C(107)O(117)
and
plane
N(122′)C(91′)O(114′) is 26.02° in 1∙BF4, and that of plane
N(1)C(9)O(1) and plane N(3′)C(24′)O(4′) is 26.73° in 1∙ClO4.
Thus, ACPs 1∙BF4 and 1∙ClO4 adopt a 1D infinite zigzag structure

ditopic anion binding ligand, each cation 1 binds two PF6
simultaneously. Therefore, complex 1∙PF6 shows an infinite one-
dimensional structure, which can be viewed as anion coordination
polymers, or ACPs, in which the hexafluorophosphate anions
function as the coordination nodes like the metal ions in CPs. In this
polymeric structure, the anions are regularly arranged in an almost
linear array, and a 1D infinite zigzag hydrogen bonding polymeric


as that of 1∙PF6, with tetrahedral BF4 or ClO4 as node and bended
cations 1 as ligand (Fig. 3(a) and 4(a). The binding atoms F(1) in
ACP 1∙BF4 and O(7) in ACP 1∙ClO4 are almost aligned
(F(1)∙∙∙F(1)∙∙∙F(1) angle 175.32° and O(7)∙∙∙O(7)∙∙∙O(7) angle
176.03°), with the distances between two binding atoms are 18.79 Å
(1∙BF4) and 18.81 Å (1∙ClO4), respectively.

chain are formed by the bended cation 1 together with bridged PF6

(Fig. 2(a). The fluorine atoms F(3) in PF6 which is used to bind
with amide group are regularly arranged in an almost linear array,
wherein the distance between two adjacent F atoms and the
F(3)∙∙∙F(3)∙∙∙F(3) angle are 18.79 Å and 172.54°, respectively.
Fig. 3 The crystal structure of 1∙BF4. (a) 1D ACPs; (b) anion
coordination environment in ACPs.
(2) Complexes with CF3 group
Infinite arrangement can also be found in complex 2∙BF4, while in a
different way from complexes with nitro group, owing to the
differences in their shapes as well as electron-withdrawing properties.
In 2∙BF4, hydrogen bonds are formed between two adjacent amide
NHs as well as tetrafluoroborate anions and aromatic CHs in
dppm ligands (Fig. 5(b). The hydrogen bond distances and angles in
2∙BF4 are listed in Table 2. Two amide groups in adjacent complexes
Fig. 2 The crystal structure of 1∙PF6. (a) 1D ACPs; (b) anion
coordination environment in ACPs.
Complexes 1∙BF4 and 1∙ClO4 adopt a similar structure with that
of 1∙PF6 owing to the same substituent group NO2 they have. The
hydrogen bond distances and angles in 1∙BF4 and 1∙ClO4 are listed form the NH∙∙∙O hydrogen bond, which is the basic interaction in
in Table 2. Each tetrafluoroborate or perchlorate anion is surrounded this system to maintain the polymeric structure. The two amide
by two amide clefts of two trinuclear copper(I) complexes and groups are in almost right-angle bended arrangement, with the
coordinated mainly by two hydrogen bonds from amide groups,
which were supplemented by additional CH∙∙∙F or CH∙∙∙O
dihedral angle of plane N(1)C(18)O(1) and plane
N(2′)C(92′)O(2′) being 80.94°. The NH∙∙∙O hydrogen bonds with
4 | J. Name., 2012, 00, 1-3
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N∙∙∙O distance at 2.8566 Å and angle at 135°, respectively, are coordination environment in ACPs.
(3) Complexes without substituent group
Different from complexes with electron-withdrawing groups, the
cation 3 in complex 3∙BF4 could not bind two anions at the same
supplemented by two additional CH∙∙∙F interactions between dppm
ligands and tetrafluoroborate anion. Tetrafluoroborate anions in
2∙BF4 are two-coordinated. The hydrogen bond distances (C∙∙∙F) and
angles of CH∙∙∙F in 2∙BF4 are in the range of 3.300(4)3.459(5) Å
and 139°169°, respectively (Table 2). The dihedral angle of
adjacent Cu3 planes (plane Cu(1)Cu(2)Cu(3) and plane
Cu(1′)Cu(2′)Cu(3′)) is 71.35°, which is in accord with the right-
angle arrangement of amide groups. The dihedral angle between two
benzene rings used to bind anions is 72.32°. In addition, the
View Article Online
DOI: 10.1039/C5RA18534C
time, and thus ACPs could not be observed in this system. In

complex 3∙BF4, anions BF4 are two-coordinated (Fig. 6(b). A
NH∙∙∙F hydrogen bond (N∙∙∙F distance 2.870(6) Å; NH∙∙∙F angle
144°) and an additional CH∙∙∙F bond (C∙∙∙F distance 3.381(7) Å;
CH∙∙∙F angle 156°) are used to coordinate one of the amide groups
in cation 3 (Table 2). In addition, two adjacent cations are
interconnected via N(1)H(1)∙∙∙O(2) with N∙∙∙O distance at 2.957(6)
Å and angle at 154°, respectively, and two supporting interactions

BF4 anions are regularly arranged in an almost right-angle array,
wherein the distance between two boron atoms and the
B(1)∙∙∙B(1)∙∙∙B(1) angle are 16.03 Å and 88.17°, respectively. Thus, C(5)H(5)∙∙∙O(2) and C(11)H(11)∙∙∙O(2) (the C∙∙∙O distances and
complex 2∙BF4 can be regarded as a zigzag 1D ACP formed between
cations 2 and bridged BF4 (Fig. 5(a).
angles range from 3.256(6)3.333(9)
Å
and 144°155°,

respectively), which results in an infinite construction (Table 2). The
dihedral angle of plane N(1)C(9)O(1) and plane
N(2′)C(24′)O(2′) is 74.12° and the dihedral angle of adjacent Cu3
planes (plane Cu(1)Cu(2)Cu(3) and plane Cu(1′)Cu(2′)Cu(3′))
is 86.63°, which is in accord with the right-angle arrangement of
amide planes. As a ditopic ligand, cations 3 form a 1D infinite meso-
helical hydrogen bonding polymeric chain with a counter anion

bound in each cation (Fig. 6(a). The BF4 anions are regularly
arranged in an almost right-angle array, wherein the distance
between two boron atoms and the B(4)∙∙∙B(4)∙∙∙B(4) angle are 20.84
Å and 72.17°, respectively. The meso-helical chain in complex
3∙BF4 has a pitch length of 24.55 Å.
Fig. 4 The crystal structure of 1∙ClO4. (a) 1D ACPs; (b) anion
coordination environment in ACPs.
Fig. 6 The crystal structure of 3∙BF4, (a) 1D polymeric chain; (b)
anion coordination environment in ACPs.
(4) Complexes with OCH3 group
In complex 4∙BF4, one of the amide group in cation 4 coordinates the

counter anion BF4 via a NH∙∙∙F hydrogen bond, which is
supplemented by two additional CH∙∙∙F bonds (Fig. 7.
Tetrafluoroborate anions in 4∙BF4 are three-coordinated. The
Fig. 5 The crystal structure of 2∙BF4. (a) 1D ACPs; (b) anion
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group 2∙BF4 are unable to bind anions by their amide groups, due to
the less acidity of amide NHs here. In 2∙BF4, zigzag polymeric
hydrogen bond distance and angle of NH∙∙∙F in 4∙BF4 are 3.077(6)
Å
and 162°, and those of CH∙∙∙F are in the range of
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chains are formed via hydrogen bonds between two amide groups in
3.326(7)3.343(8) and 144°166°, respectively (Table 2).
Å
DOI: 10.1039/C5RA18534C
adjacent complexes and supported by interactions between dppm
However, different from complexes with electron-withdrawing
group, 4∙BF4 is unable to bind two anions simultaneously, therefore
cannot construct stable polymeric chain using anions as nodes.
Complex 4∙F was obtained upon addition of excess fluoride
anions into the solution of 4∙BF4. Its structure is similar to complex
4∙BF4, consisting of a bended cation 4 and a fluoride anion bound at
one side by amide group (Fig. 8(b). Hydrogen bonds involve
fluoride anions in this system include N(1)H(1A)∙∙∙F(1) (N∙∙∙F
distance 2.805(3) Å; NH∙∙∙F angle 165°) and two additional
CH∙∙∙F bonds (C∙∙∙F distance 3.141(4) Å; NH∙∙∙F angle
126°°) (Table 2). Due to the stronger basicity and smaller size
of fluoride anion, the average hydrogen bond distance in 4∙F is
shorter than 4∙BF4 considerably. Furthermore, resemble complex
3∙BF4, two cations in 4∙F are held together by N(2)H(2A)∙∙∙O(1)
(N∙∙∙O distance 3.241(3) Å; NH∙∙∙O angle 146°), and supported by
C(27)H(27A)∙∙∙O(1) (C∙∙∙O distance 3.522(3) Å; CH∙∙∙O angle
168°). The dihedral angle of plane N(1)C(9)O(1) and plane
N(2′)C(25′)O(3′) is 54.87°. Two adjacent Cu3 planes (plane
Cu(1)Cu(2)Cu(3) and plane Cu(1′)Cu(2′)Cu(3′)) are nearly
parallel, with a dihedral angle being 0° and the identity distance
being 15.94 Å. In the meanwhile, the anions are regularly arranged
in an almost linear array, wherein the distance between two fluoride
anions and the F(1)∙∙∙F(1)∙∙∙F(1) angle are 17.91 Å and 180.00°,
respectively. Therefore, cations 4 together with F form the 1D
infinite linear hydrogen bonding polymeric chains (Fig. 8(a).
ligands and tetrafluoroborate anion. While in complex without
substituent group 3∙BF4, 1D ACP could not be observed owing to the
absence of the electron-withdrawing group. However, adjacent
cations are interconnected to construct a 1D infinite meso-helical
hydrogen bonding polymeric chain with a counter anion bound in
each cation. As for complexes with electron-donating group, 4∙BF4
and 4∙F, structures varied dramatically with different anions. Owing
to the weak hydrogen bond donor in 4∙BF4, polymeric structure
could not be found. However, with stronger base F, infinite linear
chains are formed by amide groups’ hydrogen bonds and anions are
bound to one of the amide groups. As what we can see, assembly of
various anions and cations with different substituent groups results
in the diversity of trinuclear copper(I) acetylide complexes.
Fig. 8 The crystal structure of 4∙F, (a) 1D polymeric chain; (b) anion
coordination environment in polymeric chain.
Electronic absorption and emission spectra of complexes
1∙BF44∙BF4
The photophysical data for complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4
and 4∙F are summarized in Table 3. For comparison, the photopysics
of acetylide ligands L1L4 are studied and listed in Table S7 (ESI†),
as well. The electronic absorption spectrum of 1∙BF4 in DMSO at
298 K (Fig. S2, ESI†) shows a high-energy band at ca. 266 and a
shoulder at ca. 302 nm, which are assigned to ligand-centred π
π*(dppm) and π π*(acetylide) transitions, respectively, owing
to the similar absorption energies with those of the free dppm ligand
and acetylenes. The lower energy absorption shoulder at ca. 336 nm
is probably the charge transfer transition from the amide to the NO2
group in the acetylide ligand. The electronic absorption spectra of
complexes 1∙PF6 and 1∙ClO4 are similar to that of 1∙BF4 (Fig. S2,
ESI†), indicating that counter anions exert slight effect on absorption
intensity and wavelength. The electronic absorption spectra of non-
nitro derivatives 2∙BF44∙BF4 in DMSO at 298 K (Fig. S3, ESI†)
exhibit two absorption bands at ca. 268 and 345350 nm. The band
Fig. 7 (a) The crystal structure of 4∙BF4; (b) anion coordination
environment in 4∙BF4.
(5) Structural diversity of complexes
Seven complexes reported in this work bear five kinds of
architectures (Fig. 9). In complexes with nitro group 1∙BF4, 1∙PF6,
and 1∙ClO4, each anion is bound to two ligands from adjacent
complexes at amide sites. In other words, 1D zigzag polymeric
chains are formed using anions as node and complexes as cations. In
this case, difference in anions results merely in different angles,
rather than diverse architectures. When compared with nitro-
substituted complexes, complexes with less electron-withdrawing
6 | J. Name., 2012, 00, 1-3
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View Article Online
DOI: 10.1039/C5RA18534C
Fig. 9 Polymeric structural diversity of complexes reported in this paper (for complexes with nitro group, 1∙BF4 is shown as an example).
Table 2 Selected hydrogen bonding parameters for 1∙BF4, 1∙PF6, 1∙ClO4, 2∙BF4, 3∙BF4, 4∙BF4 and 4∙F.
Complexes
1∙BF4
d(H∙∙∙A)
2.28
2.49
2.49
2.42
2.41
2.48
2.50
2.50
2.36
2.47
2.47
2.18
2.54
2.54
2.16
2.48
2.47
2.13
2.51
2.23
2.51
2.41
2.48
2.59
1.95
2.40
2.48
d(D∙∙∙A)
2.9773
3.2826
3.3395
3.2179
3.1336
3.3478
3.3259
3.3152
3.075(9)
3.291(11)
3.342(12)
2.852(3)
3.459(5)
3.300(4)
2.957(6)
3.256(6)
3.333(9)
2.870(6)
3.381(7)
3.077(6)
3.326(7)
3.343(8)
3.244(4)
3.527(4)
2.811(5)
3.189(5)
3.140(5)
Symmetry Code
DH∙∙∙A
d(DH)
0.86
0.86
0.93
0.86
0.86
0.93
0.93
0.93
0.88
0.88
0.95
0.86
0.93
0.93
0.86
0.93
0.93
0.86
0.93
0.88
0.95
0.95
0.88
0.95
0.88
0.95
0.95
∠(DHA)
138
153
152
154
142
155
147
146
138
155
152
135
169
139
154
142
155
144
156
162
144
166
146
168
165
140
126
N(120)H(12B)∙∙∙F(1)
N(122)H(12A)∙∙∙F(1)
C(89)H(89A)∙∙∙F(1)
N(1)H(1)∙∙∙F(3)
N(3)H(3)∙∙∙F(3)
C(7)H(7)∙∙∙F(2)
1x, 1/2+y, 1/2-z
1∙PF6
x, 1/2+y, 1/2-z
1/2-x, 1/2-y, z
x, 1/2+y, 1/2z
x, 1/2+y, 1/2z
1/2-x, 1/2-y, z
3/2-x, 1/2-y, z
2x, 1/2+y, 1/2z
2x, 1/2+y, 1/2z
1/2x, -1/2+y, 1/2z
x, 1+y, z
C(7)H(7)∙∙∙F(3)
C(20)H(20)∙∙∙F(5)
N(1)H(1)∙∙∙O(7)
N(3)H(3)∙∙∙O(7)
C(20)H(20)∙∙∙O(7)
N(1)H(1)∙∙∙O(2)
C(56)H(56)∙∙∙F(1)
C(65)H(65)∙∙∙F(2)
N(1)H(1)∙∙∙O(2)
C(5)H(5)∙∙∙O(2)
C(11)H(11)∙∙∙O(2)
N(2)H(2)∙∙∙F(13)
C(20)H(20)∙∙∙F(14)
N(2)H(2)∙∙∙F(2)
C(21)H(21)∙∙∙F(2)
C(27)H(27)∙∙∙F(2)
N(2)H(2A)∙∙∙O(1)
C(27)H(27A)∙∙∙O(1)
N(1)H(1A)∙∙∙F(1)
C(7)H(7A)∙∙∙F(1)
C(15)H(15A)∙∙∙F(1)
1∙ClO4
2∙BF4
3∙BF4
1/2-x, 1/2+y, 1/2z
x,-y,1/2+z
x,-y,1/2+z
x,-y,1/2+z
4∙BF4
4∙F
x, 1/2y, 1/2+z
x, 1/2y, 1/2+z
x, 1/2y, 1/2+z
1+x, y, z
1+x, y, z
1/2+x, 3/2y, 1/2+z
1/2+x, 3/2y, 1/2+z
1/2+x, 3/2y, 1/2+z
DMSO solutions. Fig. 10 displays the emission spectrum of 3∙BF4 in
the solid state at 298 K, in which a broad band at ca. 514 nm and a
shoulder at ca. 557 nm are observed. The spacing of the adjacent
band 3∙BF4 is ca. 1500 cm1, which is typical of ground-state
aromatic ν (C∙∙∙C) stretching frequency.45 The solid state emission
spectra of 1∙BF4, 2∙BF4, 4∙BF4, 1∙PF6, 1∙ClO4 and 4∙F (Figs. S510,
ESI†) are similar to that of 3∙BF4 with lifetimes in microsecond
range, which is suggestive of the involvement of a spin-forbidden
transition. In general, the complexes with electron-rich acetylides
emit at a lower energy. The electron-donating substituent R would
at ca. 268 nm is ascribed to ligand-centred ππ* (dppm) transition,
while low-energy bands at 345350 nm are assigned as the
admixture of metal-perturbed ligand-centered π-π* (acetylide) and
LMCT (acetylide → Cu3) transition.4445 4∙F shows similar
electronic absorption spectrum with 4∙BF4, expect for the slight
decrease in the molar absorption coefficient (Fig. S4, ESI†).
Excitation at λ > 370 nm of complexes 1∙BF44∙BF4, 1∙PF6,
1∙ClO4 and 4∙F in the solid state and in DMSO solution results in
long-lived and intense luminescence in the visible light regime at
298 K, with emission quantum yields of 1.4 × 1028.6 × 102 in
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increase the energy of the π orbital of the acetylides and thus concentration of the added anions, owing to the small changes in the
decrease the energy of the LMCT excited state. Therefore, the origin
amide NH (Ha) chemical shifts. As a result, we could only compare
of the emission is proposed to involve substantial 3LMCT [acetylide
the signal changes upon addition of different anionVsieiwnArtthicele Osanmlinee
→ Cu3] character.4445 In DMSO solution, trinuclear copper(I) amount. In general, the signal changes of dDifOfeIr:e1n0t.10co39m/Cp5leRxAe1s85w34itCh
the same anion are in the following order: R = NO2 (1∙BF4) > CF3
(2∙BF4) > H (3∙BF4) > OCH3 (4∙BF4), which is in line with the
decreasing of the electron-withdrawing ability of substituent R on
the acetylide ligands (Fig. S22, ESI†). This could be rationalized by
the fact that the stronger electron-withdrawing substituent R on the
acetylide ligand could induce higher acidity of amide group, which
strengthen the hydrogen bond interactions between complexes and
anions. The signal changes of the same complex with the various
anions are in the following order: OAc > Cl > Br > I, which is in
line with the decreasing of the basicity of anions (Fig. 11).
acetylide complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F exhibit
blue-green to yellow-green emission at 298 K (Fig. S1117, ESI†).
A broad band at ca. 475500 nm is observed, which follows the
same trend with that in solid state. Thus, the emission in DMSO
solution is ascribed to LMCT as well.4445 For the trinuclear
copper(I) acetylide complexes studied in this paper, the emission
energies depend mainly on the substituent R on the acetylide ligand,
while the type of counter anions have little effect on the electronic
absorption as well as emission spectra both in solid state and DMSO
solution.
The interactions of 1∙BF44∙BF4 with Fwere investigated and
exhibited different spectral changes from other anions. Fig. S23
1
(ESI†) shows the H NMR spectral changes of 1∙BF4 in DMSOd6
514
upon addition of F. The significant downfield shift of the signal of
amide NH (Ha) is observed upon addition of F from 0 to 1 equiv,
while this peak disappear rapidly when the amount of Fadded was
larger than 1 equiv, and the aromatic proton signals Hb and Hd
showed a slight upfield shift, which could be ascribed to the
deshielding effect resulting from the increased electron density of
the phenyl ring,65 induced by the deprotonation of the amide NH
unit. During the addition of F, the color of the solution of 1∙BF4 in
DMSOd6 changes from orange to dark red. After the addition of 3
equiv of F, a distinct triplet centered at 16.08 ppm (J = 120 Hz)
appears, which is assigned as the formation of HF26667In addition,
its 19F NMR spectrum also displays a distinct doublet centered at
557
500 550 600 650 700 750
Wavelength / nm
Fig. 10 Emission spectrum of 3∙BF4 in the solid state at 298 K (λex
143.13 ppm (J = 117 Hz) (Fig. S24, ESI†), suggesting the
=
 6667
formation of HF2 .
These results indicate the deprotonation of
428 nm).
the amide NH of 1∙BF4 upon addition of Fin DMSOd6.
Complexes 1∙PF6, 1∙ClO4 and 2∙BF44∙BF4 show similar color and
spectral changes upon addition of F, which could be ascribed to
deprotonation as well (Fig. S25S34, ESI†).
Anion binding properties of complexes 1∙BF44∙BF4
The anion-binding properties of complexes 1∙BF44∙BF4 have been
investigated by 1H NMR spectroscopy. The results of 1H NMR
titration studies with a variety of anions show that even in a
competitive solvent (DMSOd6) interactions and selectivity could
still be observed. All of the anions used were in the form of tetra-n-
butylammonium salts. Unfortunately, due to the decomposition of
the trinuclear complexes upon addition of NBu4H2PO4 and
We have also examined the color change of complexes 1∙BF4
with different anions in DMSO (Fig. S35 and S36, ESI†). No color
change of 1∙BF4 in DMSO could be observed upon addition of
anions, except F. Thus, 1∙BF4 shows selective color change towards
F− in DMSO. Complexes 2∙BF44∙BF4 exhibited similar selectivity
through dramatic color change, which allows F− detection with
naked eyes. Even though addition of the anions studied in this paper
into the solutions of 1∙BF44∙BF4 did cause their UV-Vis spectral
changes, the changes were too small to compare the binding abilities
of complexes 1∙BF44∙BF4 towards anions.


NBu4HSO4, the investigations toward H2PO4 and HSO4 were not
carried out.
1
Fig. S18 (ESI†) shows the H NMR spectral changes of 1∙BF4
upon addition of Cl in DMSOd6. Upon the addition of chloride
anion, the signals of the NH protons (Ha) show a relatively
considerable downfield shift, while the other proton signals are
found to undergo essentially negligible changes, which suggests the
formation of a hydrogen bonding interaction between the amide
groups in 1∙BF4 and Cl. The slight downfield shift of protons Hc
and Hd on the phenyl ring is ascribed to the polarization effect of the
CH bond that is introduced by the through-space effect.6264
Analogous investigations have also been carried out with Yshape
anion OAc and larger halides Br and I(Fig. S1921, ESI†). The
magnitude of the complexation-induced 1H NMR shift upon addition
of OAcis larger when compared with that of Cl, while the signal of
the NH protons (Ha) shows slight change with Br, and none when
Iwas added. For other complexes, 2∙BF44∙BF4, the anion binding
properties were also studied (Fig. 11 and S22, ESI†), which show
similar binding trend with 1∙BF4, but weaker binding ability.
Conclusions
In summary, a series of discrete or polymeric amide based trinuclear
copper(I) complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F have been
synthesized and characterized, with their crystal structures
determined. Among them, 1 D hydrogen bonding polymeric chain
with zigzag, meso-helical or linear structures are observed. The
architectures of these complexes could be perturbed by anions and
the R group on “Cu3 cluster ligands”. Complexes 1∙BF44∙BF4,
1∙PF6, 1∙ClO4 and 4∙F exhibit luminescence both in the solid state
and in the DMSO solution at 298 K. The anion binding abilities of
complexes 1∙BF44∙BF4 toward different anions have also been
studied by NMR and UV-vis. Their selective color change upon
addition of F enables the naked eye detection of F.
Unfortunately, we were unable to obtain the anion-binding
constants of complexes 1∙BF44∙BF4 by nonlinear least-square fits
of the shifts of the signals of amide NH (Ha) versus the
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Table 3 Photophysical data of complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F at 298 K.
View Article Online
λabs / nm (ε / dm3mol1cm1)
complexes
medium
DMSO
solid
λem / nm (εem / τs)
Φem
DOI: 10.1039/C5RA18534C
1∙BF4
266 (83540), 302 (sh, 60910), 336 (sh, 45460)
474 (0.1)
0.014
505 (7.3)
1∙PF6
1∙ClO4
2∙BF4
3∙BF4
4∙BF4
4∙F
DMSO
solid
DMSO
solid
DMSO
solid
DMSO
solid
DMSO
solid
DMSO
solid
266 (85860), 302 (sh, 63030), 336 (sh, 46570)
266 (90910), 302 (sh, 63430), 336 (sh, 44440)
268 (58990), 350 (44950)
474 (0.1)
504 (max, 6.7), 544 (sh)
474 (0.1)
506 (11.1)
475 (0.1)
507 (14.7)
502 (0.3)
514 (max, 75.3), 557 (sh)
500 (0.3)
514 (max, 21.9), 557 (sh)
499 (0.3)
0.016
0.015
0.051
0.078
0.086
0.078
268 (60810), 346 (45760)
268 (58180), 345 (47880)
268 (55660), 345 (46970)
513 (25.1)
OAc-
(b)
Cl-
OAc-
Cl-
Br-
I-
(a)
Br-
I-
0.8
0.6
0.4
0.2
0.0
0.6
0.4
0.2
0.0
0.00
0.01
0.02
0.03
0.04
0.05
0.00
0.01
0.02
0.03
0.04
0.05
dm3
[Anion
]
/ mol
dm3
[Anion
]
/ mol

OAc-
Cl-
Br-
I-
OAc-
Cl-
Br-
I-
(c)
(d)
0.4
0.3
0.2
0.1
0.0
0.3
0.2
0.1
0.0
0.00
0.01
0.02
0.03
0.04
0.05
0.00
0.01
0.02
0.03
0.04
dm-3
0.05
[Anion
]
/ mol

dm-3
[Anion
]
/ mol

Fig. 11 The shifts of the signals of amide NH (Ha) of complexes (a) 1·BF4, (b) 2·BF4, (c) 3·BF4, and (d) 4·BF4 upon addition of different
anions with different concentrations in DMSOd6 at 298 K.
purchased from AlfaAesar. 4Ethylnylaniline and tetra-n-
butylammonium iodide were purchased from Acros. 4Nitrobenzoyl
chloride was purchased from TCI. 4Methoxybenzoyl,
4trifluoromethylbenzoyl chloride and tetranbutylammonium
bromide hydrate were obtained from J&K. Tetranbutylammonium
fluoride hydrate and tetranbutylammonium acetate was obtained
from SigmaAldrich. All reactions were carried out under anhydrous
and anaerobic conditions using standard Schlenk techniques under
Experimental section
Materials and reagents
Dinuclear complexes [Cu2(µ-dppm)2(CH3CN)4](BF4)2, [Cu2(µ-
dppm)2(CH3CN)4](PF6)2, and [Cu2(µ-dppm)2(CH3CN)4](ClO4)2 were
synthesized
according
to
literature
procedures.68
Bis(diphenylphosphino)methane (dppm) and benzoyl chloride were
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 9

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Page 10 of 12
Journal Name
ARTICLE
nitrogen. All solvents were purified and distilled using standard and the residue was washed with water and n-hexane to yield pale
procedures before use. All other reagents were of analytical grade yellow solid.
1
View Article Online
and were used as received.
L1. Yield: 123.5 mg, 56 %． H NMR (DMSOd6, 298K):  = 10.71
(s, 1H, NH), 8.36 (d, 2H, J = 9 Hz, aromaticDrOinI:g1)0，.1083.196/C(5dR,A21H85,3J4C=
9 Hz, aromatic ring), 7.80 (d, 2H, J = 9 Hz, aromatic ring), 7.48 (d,
2H, J = 9 Hz, aromatic ring), 4.15 (s, 1H, HC≡C). IR (KBr, cm1): 
= 3255 (NH), 2098 (C≡C), 1654 (C=O). ESI-MS: m/z = 265 [M 
H]. Anal. Calcd for C15H10N2O3 (%): C, 67.67; H, 3.79; N, 10.52.
Found: C, 67.41; H, 3.80; N, 10.48.
L2. Yield: 139.8 mg, 60 %．1H NMR (DMSOd6, 298K):  = 10.60
(s, 1H, NH), 8.12 (d, 2H, J = 9 Hz, aromatic ring)，7.91 (d, 2H, J =
8 Hz, aromatic ring), 7.80 (d, 2H, J = 9 Hz, aromatic ring), 7.47 (d,
2H, J = 9 Hz, aromatic ring), 4.14 (s, 1H, HC≡C). IR (KBr, cm1): 
= 3302 (NH), 2116 (C≡C), 1657 (C=O). ESI-MS: m/z = 288 [M 
H]. Anal. Calcd for C16H10F3NO (%): C, 66.44; H, 3.48; N, 4.84.
Found: C, 66.40; H, 3.47; N, 4.83.
L3. Yield: 115.2 mg, 56 %．1H NMR (DMSOd6, 298K):  = 10.40
(s, 1H, NH), 7.92 (d, 2H, J = 8 Hz, aromatic ring), 7.80 (d, 2H, J = 9
Hz, aromatic ring), 7.617.44 (m, 5H, aromatic ring), 4.12 (s, 1H,
HC≡C). IR (KBr, cm1):  = 3299 (NH), 2106 (C≡C), 1659 (C=O).
ESI-MS: m/z = 256 [M  H] Anal. Calcd for C15H11NO (%): C,
81.43; H, 5.01; N, 6.33. Found: C, 80.41; H, 5.01; N, 6.35.
L4. Yield: 174.2 mg, 59 %．1H NMR (DMSOd6, 298K):  = 10.22
(s, 1H, NH), 7.93 (d, 2H, J = 9 Hz, aromatic ring)，7.79 (d, 2H, J =
8 Hz, aromatic ring), 7.43 (d, 2H, J = 9 Hz, aromatic ring), 7.05 (d,
2H, J = 9 Hz, aromatic ring), 4.10 (s, 1H, HC≡C), 3.83 (s, 3H,
OCH3). IR (KBr, cm1):  = 3283 (NH), 2106 (C≡C), 1658 (C=O).
ESI-MS: m/z = 250 [M  H]. Anal. Calcd for C16H13NO2 (%): C,
76.48; H, 5.21; N, 5.57. Found: C, 76.50; H, 5.22; N, 5.55.
Physical measurements and instrumentation
Chemical shifts (δ, ppm) were reported relative to tetramethylsilane
1
for H NMR, and NaF for 19F NMR on a Varian MercuryPlus 300
spectrometer, 85% H3PO4 for 31P NMR on a Bruker Avance III 400
MHz spectrometer. Emission spectra were obtained on a FLS980
fluorescence spectrophotometer. The solution emission quantum
yields were measured using quinine sulfate in 1.0 N sulfuric acid as
standard69 (Φr = 0.546, excitation wavelength at 365 nm) and
calculated by Φem = Φr (Br/Bs)(ns/nr)2(Ds/Dr), where the subscripts s
and r refer to sample and reference standard solution respectively, n
is the refractive index of the solvents, D is the integrated intensity,
and Φ is the luminescence quantum yield. The quantity B is
calculated by B = 110AL, where A is the absorbance at the
excitation wavelength and L is the optical path length. Infrared
spectra were recorded from KBr pellets in the range of 4004000
cm1 on a BrukerEQUINOX 55 FTIR spectrometer. Electrospray
ionization (ESI) mass spectra were recorded on a LCQ DECA XP
quadrupole ion trap mass spectrometer and mass spectra of ligands
L1L4 and complexes 1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F are
listed in Fig. S37 and S38 (ESI†), respectively. Elemental analysis
was performed on an Elemental Vario EL elemental analyzer.
Crystal structure determination
Crystals were grown by diffusion of diethyl ether into concentrated
solution of the corresponding complexes. Single crystals of
1∙BF44∙BF4, 1∙PF6, 1∙ClO4 and 4∙F were carefully picked and
coated in paratone oil, attached to a glass silk inserted in a stainless
steel stick, then quickly transferred to the Agilent Gemini S Ultra
CCD Diffractometer with the Enhance X-ray Source of Cu radiation
(λ = 1.54178 Å) using the ω-ϕ scan technique. Structural solution
and refinement against F2 were carried out using the SHELXL
programs.70 Hydrogen atoms were placed in geometrically calculated
positions and included in the refinement process using riding model
with isotropic thermal parameters: Uiso(H) = 1.2Ueq(-CH). For
structures of 1∙BF44∙BF4, 1∙ClO4 and 4∙F, the contribution of
heavily disordered solvent molecules was treated by the Squeeze
procedure implemented in Platon.7172 Crystallographic data for the
structures reported in this paper have been deposited in the
Cambridge Crystallographic Data Centre as supplementary
publication, CCDC 14215921421598 for 1∙BF4, 1∙ClO4, 1∙PF6,
2∙BF44∙BF4 and 4∙F.
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-NO2)2BF4]∞
(1·BF4). To a solution of [Cu2(µ-dppm)2(CH3CN)4](BF4)2 (100.8
mg, 0.082 mmol) and L1 (29.0 mg, 0.11 mmol) in degassed CH3CN
(50 mL), NEt3 (1 mL) was added. The mixture was stirred overnight
under nitrogen. After evaporation to dryness, the solid residue was
collected and washed with water and diethyl ether. Subsequent
diffusion of diethyl ether into the concentrated CH3CN solution gave
orange crystals. Yield: 90.6 mg, 85 %.1H NMR (CD3CN, 298K):  =
9.19 (s, 2H, NH), 8.40 (d, 4H, J = 9 Hz, aromatic ring), 8.21 (d, 4H,
J = 9 Hz, aromatic ring), 7.90 (d, 4H, J = 9 Hz, aromatic ring), 7.47
(d, 4H, J = 9 Hz, aromatic ring), 7.186.83 (m, 60H, aromatic ring),
3.37 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  = 5.96 (s). 19F
NMR (CD3CN, 298K):  = 151.65 (s, 10BF4 ), 151.70 (s, 11BF4 ).
IR (KBr, cm1):  = 3373 (NH), 2138 (C≡C), 1672 (C=O). ESI-MS:
m/z = 1874 [M]+. Anal. Calcd for C105H84Cu3BF4N4O6P6 (%): C,
64.31; H, 4.32; N, 2.86. Found: C, 64.34; H, 4.30; N, 2.87.


[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-NO2)2PF6]∞
(1·PF6). To a solution of [Cu2(µ-dppm)2(CH3CN)4](PF6)2 (159.0 mg,
0.11 mmol) and L1 (41.9 mg, 0.16 mmol) in degassed CH3CN (50
mL), NEt3 (1.5 mL) was added. The mixture was stirred overnight
under nitrogen. After evaporation to dryness, the solid residue was
collected and washed with water and diethyl ether. Subsequent
diffusion of diethyl ether into the concentrated CH2Cl2 solution gave
orange crystals. Yield: 147.6 mg, 93 %. 1H NMR (CD3CN, 298K): 
= 9.30 (s, 2H, NH), 8.54 (d, 4H, J = 9 Hz, aromatic ring), 8.34 (d,
4H, J = 9 Hz, aromatic ring), 8.04 (d, 4H, J = 9 Hz, aromatic ring),
7.61 (d, 4H, J = 9 Hz, aromatic ring), 7.326.97 (m, 60H, aromatic
ring), 3.37 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  = 5.95,
Titrations
1
For a typical H NMR titration experiment, 1 μL aliquots of a tetra-
n-butylammonium salt (5.00×101 moldm3 in DMSOd6) were
added into the 0.5 mL solution of the copper(I) acetylide complex in
DMSOd6 (5.00×103 moldm3) by a syringe, and the H NMR
spectral changes were recorded by a Varian MercuryPlus 300
spectrometer at 298 K.
1
Synthesis

144.65 (quint, PF6 ). 19F NMR (CD3CN, 298K):  = 73.53 (d, J =
General procedure for the synthesis of H-C≡CC6H4-4-NHC(O)-
C6H4-R (R = NO2 (L1), CF3 (L2), H (L3), OCH3 (L4)). To a
solution of 4-ethylnylaniline and 1 equiv of the corresponding acyl
chloride in CHCl3 was added triethylamine. The mixture was heated
700 Hz). IR (KBr, cm1):  = 3399 (NH), 2321 (C≡C), 1677 (C=O).
ESI-MS: m/z = 1874 [M]+. Anal. Calcd for C105H84Cu3F6N4O6P7 (%):
C, 62.46; H, 4.19; N, 2.77. Found: C, 62.44; H, 4.15; N, 2.72.
to reflux for 18 h. The solvent was removed under reduced pressure, [Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-NO2)2ClO4]∞
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

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(1·ClO4). To a solution of [Cu2(µ-dppm)2(CH3CN)4](ClO4)2 (106.7 66.52; H, 4.71; N, 1.46.
mg, 0.085 mmol) and L1 (30.3 mg, 0.11 mmol) in degassed CH3CN
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-OCH3)2F]∞
View Article Online
(50 mL), NEt3 (1 mL) was added. The mixture was stirred overnight
under nitrogen. After evaporation to dryness, the solid residue was
collected and washed with water and diethyl ether. Subsequent
diffusion of diethyl ether into the concentrated CH2Cl2 solution gave
(4·F). To a solution of 4·BF4 (76.8 mg, 0.062 mmol) in CH3CN,
NBu4F (102.3 mg, 0.39 mmol) in CH3CN wDasOIa:d1d0e.1d03d9r/oCp5wRAis1e8.5T34hCe
mixture was stirred overnight. The yellow precipitate was collected
and washed by acetonitrile. Subsequent diffusion of diethyl ether
orange crystals. Yield: 98.0 mg , 88 %.1H NMR (CD3CN, 298K):  = into the concentrated CH3OH solution gave pale yellow crystals.
Yield: 9.0 mg, 12 %. 1H NMR (DMSOd6, 298K):  = 8.12 (d, 4H, J
8.98 (s, 2H, NH), 8.21 (d, 4H, J = 9 Hz, aromatic ring), 8.02 (d, 4H,
J = 9 Hz, aromatic ring), 7.71 (d, 4H, J = 8 Hz, aromatic ring), 7.28
(d, 4H, J = 9 Hz, aromatic ring), 6.976.64 (m, 60H, aromatic ring),
3.04 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  = 5.95 (s). IR (KBr,
cm1):  = 3387 (NH), 2238 (C≡C), 1674 (C=O). ESI-MS: m/z =
1874 [M]+. Anal. Calcd for C105H84Cu3ClN4O10P6 (%): C, 63.90; H,
4.29; N, 2.84. Found: C, 63.86; H, 4.27; N, 2.86.
= 9 Hz, aromatic ring), 7.92 (d, 4H, J = 9 Hz, aromatic ring), 7.26 (d,
4H, J = 9 Hz, aromatic ring), 7.206.83 (m, 64H, aromatic ring),
3.87 (s, 6H, CH3), 3.15 (s, 6H, CH2). 31P NMR (DMSOd6, 298K): 
= 6.04 (s). IR (KBr, cm1):  = 3429 (NH), 2291 (C≡C), 1654
(C=O). ESI-MS: m/z
=
1844 [M]+. Anal. Calcd for
C107H90Cu3FN2O4P6 (%): C, 68.97; H, 4.87; N, 1.50. Found: C,
68.90; H, 4.85; N, 1.51.
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-CF3)(3-1-
C≡CC6H4-4-NHC(O)C6H4-4-CF3)BF4]∞ (2·BF4). To a solution of
[Cu2(µ-dppm)2(CH3CN)4](BF4)2 (215.1 mg, 0.17 mmol) and L2
(67.3 mg, 0.23 mmol) in degassed CH3CN (50 mL), NEt3 (1 mL)
was added. The mixture was stirred overnight under nitrogen. After
evaporation to dryness, the solid residue was collected and washed
with water and diethyl ether. Subsequent diffusion of diethyl ether
into the concentrated CH3CN solution gave colorless crystals. Yield:
Acknowledgements
We acknowledge financial support from the National Natural
Science Foundation of China (20971131 and J1103305), the
Natural Science Foundation of Guangdong Province
(S2012010010566), and the Undergraduate Innovative
1
148.4 mg, 64 %. H NMR (CD3CN, 298K):  = 9.09 (s, 2H, NH),
8.19 (d, 4H, J = 9 Hz, aromatic ring), 7.91 (d, 4H, J = 9 Hz, aromatic
ring), 7.48 (d, 4H, J = 9 Hz, aromatic ring), 7.196.84 (m, 64H,
aromatic ring), 3.23 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  =
5.94 (s). 19F NMR (CD3CN, 298K):  = 64.06 (s, CF3), 151.71
Experiment
Program
of
Sun
Yat-sen
University
(201504020055). We thank Dr. Xiao-Long Feng for
crystallographic data collection.


(s, 10BF4 ), 151.77 (s, 11BF4 ). IR (KBr, cm1):  = 3368 (NH),
2262 (C≡C), 1674 (C=O). ESI-MS: m/z = 1920 [M]+. Anal. Calcd
for C107H84Cu3BF6N2O2P6 (%): C, 66.92; H, 4.41; N, 1.46. Found: C,
66.82; H, 4.45; N, 1.46.
Notes and references
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of
Chemistry and Chemical Engineering, Sun Yat-sen University,
Guangzhou 510275, P. R. China. E-mail: zhaoxy@mail.sysu.edu.cn;
Fax: +86-20-84112245; Tel: +86-20-84110062.
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H5)2BF4]∞ (3·BF4).
To a solution of [Cu2(µ-dppm)2(CH3CN)4](BF4)2 (72.4mg, 0.059
mmol) and L3 (17.3 mg, 0.078 mmol) in degassed CH3CN (50 mL),
NEt3 (1 mL) was added. The mixture was stirred overnight under
nitrogen. After evaporation to dryness, the solid residue was
collected and washed with water and diethyl ether. Subsequent
diffusion of diethyl ether into the concentrated CH3OH solution gave
colorless crystals. Yield: 50.9 mg, 70 %. 1H NMR (CD3CN, 298K): 
= 8.98 (s, 2H, NH), 8.04 (d, 4H, J = 9 Hz, aromatic ring), 7.92 (d,
4H, J = 9 Hz, aromatic ring), 7.667.57 (m, 6H, aromatic ring), 7.48
(d, 4H, J = 9 Hz, aromatic ring), 7.196.86 (m, 60H, aromatic ring),
3.25 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  = 5.98 (s). 19F
Electronic Supplementary Information (ESI) available: X-ray
crystallographic files in CIF format for complexes 1∙BF44∙BF4, 1∙PF6,
1∙ClO4
and
4∙F
.
Additional
figures
and
tables.
See
DOI: 10.1039/b000000x/.
1. N. Busschaert, C. Caltagirone, W. V. Rossom and P. A. Gale, Chem.
Rev., 2015, 115, 8038 8155.
2. F. Wang, L. Wang, X. Chen and J. Yoon, J. Chem. Soc. Rev., 2014, 43,
43124324
3. P. A. Gale, N. Busschaert, C. J. E. Haynes, L. E. Karagiannidis and I. L.


NMR (CD3CN, 298K):  = 151.67 (s, 10BF4 ), 151.72 (s, 11BF4 ).
IR (KBr, cm1):  = 3369 (NH), 2238 (C≡C), 1656 (C=O). ESI-MS:
m/z = 1784 [M]+. Anal. Calcd for C107H84Cu3BF6N2O2P6 (%): C,
66.92; H, 4.41; N, 1.46. Found: C, 66.93; H, 4.43; N, 1.43.
Kirby, Chem. Soc. Rev., 2014, 43, 205241.
4. L. Fabbrizzi and A. Poggi, Chem. Soc. Rev., 2013, 42, 16811699.
5. K. Bowman-James, A. Bianchi and E. García-Espana, Anion
Coordination Chemistry, Wiley, New York, 2012.
[Cu3(-dppm)3(3-1-C≡CC6H4-4-NHC(O)C6H4-4-OCH3)2]BF4
(4·BF4). To a solution of [Cu2(µ-dppm)2(CH3CN)4](BF4)2 (114.8
mg, 0.093 mmol) and L4 (31.6 mg, 0.13 mmol) in degassed CH3CN
(50 mL), NEt3 (1.5 mL) was added. The mixture was stirred
overnight under nitrogen. After evaporation to dryness, the solid
residue was collected and washed with water and diethyl ether.
Subsequent diffusion of diethyl ether into the concentrated acetone
and methanol mixed solution gave yellow crystals. Yield: 73.9 mg,
62 %.1H NMR (CD3CN, 298K):  = 8.90 (s, 2H, NH), 8.04 (d, 4H, J
= 9 Hz, aromatic ring), 7.92 (d, 4H, J = 9 Hz, aromatic ring), 7.48 (d,
4H, J = 9 Hz, aromatic ring), 7.186.85 (m, 64H, aromatic ring),
3.94 (s, 6H, CH3), 3.24 (s, 6H, CH2). 31P NMR (CD3CN, 298K):  =
6. P. A. Gale, Acc. Chem. Res., 2011, 44, 216226.
7. V. Amendola, D. Esteban-Gόmez, L. Fabbrizzi and M. Licchelli, Acc.
Chem. Res., 2006, 39, 343353.
8. K. Bowman-James, Acc. Chem. Res., 2005, 38, 671678.
9. C. H. Park and H. E. Simmons, J. Am. Chem. Soc., 1968, 90,
24312432.
10. J. M. Lehn, Acc. Chem. Res., 1978, 11, 4957.
11. P. D. Beer and P. A. Gale, Angew. Chem. Int. Ed., 2001, 40, 486516.
12. M. R. Sambrook, P. D. Beer, J. A. Wisner, R. L. Paul, A. R. Cowley, F.
Szemes and M. G. B. Drew, J. Am. Chem. Soc., 2005, 127, 22922302.
13. M. R. Sambrook, P. D. Beer, J. A. Wisner, R. L. Paul and A. R. Cowley,
J. Am. Chem. Soc., 2004, 126, 1536415365.
14. James A. Wisner, Paul D. Beer, Neil G. Berry and B. Tomapatanaget,
Proc. Natl. Acad. Sci., 2002, 99, 49834986.
15. J. A. Wisner, P. D. Beer, M. G. B. Drew and M. R. Sambrook, J. Am.
Chem. Soc., 2002, 124, 1246912476.
16. G. W. Bates, P. A. Gale and M. E. Light, Chem. Commun., 2007, 21,

6.04 (s). 19F NMR (CD3CN, 298K):  = 151.65 (s, 10BF4 ),

151.70(s, 11BF4 ). IR (KBr, cm1):  = 3371 (NH), 2246 (C≡C),
1662 (C=O). ESI-MS: m/z = 1844 [M]+. Anal. Calcd for
C107H90Cu3BF4N2O4P6 (%): C, 66.55; H, 4.70; N, 1.45. Found: C,
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 11

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Page 12 of 12
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