Toward luminescence vapochromism of tetranuclear AuI-Cu I clusters

Article abstract of DOI:10.1021/om301100v

A family of triphosphine gold-copper clusters bearing aliphatic and hydroxyaliphatic alkynyl ligands of general formula [HC(PPh₂) ₃Au₃Cu(C₂R)₃]⁺ (R = cyclohexyl (1), cyclopentyl (2), Bu^t (3), cyclohexanolyl (4), cyclopentanolyl (5), 2,6-dimethylheptanolyl (6), 2-methylbutanolyl (7), diphenylmethanolyl (8)) was synthesized via a self-assembly protocol, which involves treatment of the (AuC₂R)_n acetylides with the (PPh₂)₃CH ligand in the presence of Cu⁺ ions and NEt₃. Addition of Cl^- or Br^- anions to complex 8 results in coordination of the halides to the copper atoms to give neutral HC(PPh₂)₃Au₃CuHal(C ₂COHPh₂)₃ derivatives (Hal = Cl (9), Br (10)). The title compounds were characterized by NMR and ESI-MS spectroscopy, and the structures of 1, 4, 7, and 8 were determined by single-crystal X-ray diffraction analysis. The photophysical behavior of all of the complexes has been studied to reveal moderate to weak phosphorescence in solution and intense emission in the solid state with a maximum quantum yield of 80%. Exposure of the solvent-free X-ray amorphous samples 8-10 (R = diphenylmethanolyl) to vapors of the polar solvents (methanol, THF, acetone) switches luminescence with a visible hypsochromic shift of emission of 50-70 nm. The vapochromism observed is tentatively ascribed to the formation of a structurally ordered phase upon absorption of organic molecules by the amorphous solids.

Full text of DOI:10.1021/om301100v

Article
pubs.acs.org/Organometallics
Toward Luminescence Vapochromism of Tetranuclear AuI−CuI
Clusters
Julia R. Shakirova,† Elena V. Grachova,*,† Alexei S. Melnikov,‡, § Vladislav V. Gurzhiy,† Sergey P. Tunik,*,†
Matti Haukka,∥,⊥ Tapani A. Pakkanen,∥ and Igor O. Koshevoy*,∥
†Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia
‡Department of Physics, St. Petersburg State University, Ulyanovskaya Str., 1, 198504, St. Petersburg, Russia
§St. Petersburg State Polytechnical University, Polytechnicheskaya Str. 29, 195251 St. Petersburg, Russia
∥Department of Chemistry, University of Eastern Finland, Joensuu, 80101, Finland
⊥Department of Chemistry, University of Jyvaskyla, 40014 Jyvaskyla, Finland
̈
̈
̈
̈
S
* Supporting Information
ABSTRACT: A family of triphosphine gold−copper clusters
bearing aliphatic and hydroxyaliphatic alkynyl ligands of general
formula [HC(PPh2)3Au3Cu(C2R)3]+ (R = cyclohexyl (1),
cyclopentyl (2), But (3), cyclohexanolyl (4), cyclopentanolyl
(5), 2,6-dimethylheptanolyl (6), 2-methylbutanolyl (7),
diphenylmethanolyl (8)) was synthesized via a self-assembly
protocol, which involves treatment of the (AuC2R)n acetylides
with the (PPh2)3CH ligand in the presence of Cu+ ions and
NEt3. Addition of Cl− or Br− anions to complex 8 results in
coordination of the halides to the copper atoms to give neutral
HC(PPh2)3Au3CuHal(C2COHPh2)3 derivatives (Hal = Cl (9),
Br (10)). The title compounds were characterized by NMR and
ESI-MS spectroscopy, and the structures of 1, 4, 7, and 8 were
determined by single-crystal X-ray diffraction analysis. The photophysical behavior of all of the complexes has been studied to
reveal moderate to weak phosphorescence in solution and intense emission in the solid state with a maximum quantum yield of
80%. Exposure of the solvent-free X-ray amorphous samples 8−10 (R = diphenylmethanolyl) to vapors of the polar solvents
(methanol, THF, acetone) switches luminescence with a visible hypsochromic shift of emission of 50−70 nm. The
vapochromism observed is tentatively ascribed to the formation of a structurally ordered phase upon absorption of organic
molecules by the amorphous solids.
coordination provides additional opportunities for fine tuning
of the photophysical characteristics of these types of complexes.
For example, modification of the electronic properties of the
−CCR moiety affects the energy of molecular orbitals
involved in the emissive electronic transitions.1g,5 In addition to
the electronic effects, the coordinatively inactive R alkynyl
substituents were shown to participate in weak noncovalent
interactions (e.g., hydrogen bonding), which can influence both
the structural topology and photophysical characteristics of the
polynuclear aggregates.6 In particular, hydroxyaliphatic alkynyl
ligands bearing OH groups were found to form effective O−
H...O intramolecular interactions, dramatically changing the
processes of formation of multimetallic assemblies. This O−
H...O bonding was shown to lead to molecular entities which
could not be accessed using e.g. aromatic −CCR ligands.6b−e
The subtle effects of the ligand environment on the metal−
metal interactions are of particular interest, as they can provide
INTRODUCTION
■
The photophysical properties of coinage-metal compounds
have been intensely studied in recent years due to their
fascinating versatility as well as the promising potential for
technological applications in such areas as e.g. optoelectronics
and sensors.1 The luminescence characteristics of these
compounds often depend dramatically on the presence of
metal−metal interactions (metallophilicity).2 This phenomen-
on that is usually considered to be an origin of intense
photoemission is also responsible for the formation of the
families of multimetallic aggregates, which demonstrate excep-
tional diversity of composition, stereochemistry, and, con-
sequently, physical properties.1i,3
The ligand environment of the polymetallic d10 complexes
usually contains bridging organic groups, which stabilize the
cluster core and determine the architecture of the resulting
assembly.4 The ability of the alkynes to bind late-transition-
metal ions in a bidentate mode through a combination of σ and
π bonding has been extensively utilized in the synthetic
chemistry of Cu, Ag, and Au. This mode of alkynyl ligand
Received: November 15, 2012
Published: July 23, 2013
© 2013 American Chemical Society
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(m, CH2, 6H), 2.70 (m, CH, 3H). Anal. Calcd for Au3C61CuH64F6P4:
C, 43.37; H, 3.82. Found: C, 43.27; H, 3.88.
access to molecules/materials which exhibit effective lumines-
cence or absorption response to various external stimuli,
including the vapors of volatile organic compounds (VOCs).6d,7
Coinage-metal complexes showing vapochromic luminescence
in the solid state are of great interest due to their potential for
highly sensitive and easy to detect sensing of the corresponding
analytes.7,8
[HC(PPh2)3Au3Cu(C2Cyp)3]PF6 (2). This complex was recrystallized
by slow evaporation of an acetone/heptane/diethyl ether solution to
give yellow-orange platelike crystals (130 mg, 79%). ES MS (m/z):
[M]+ 1501.20 (calcd 1501.20). 31P NMR (CDCl3, 298 K; δ): 39.7 (s,
−
3P, tppm), −144.1 (sept, PF6 ). 1H NMR (CDCl3, 298 K; δ):
phosphine, 6.12 (q, H−CP3, 1H, JPH = 9.7 Hz), 7.10 (dd, H-meta,
12H, JHH = 7.4 Hz), 7.17 (t, H-para, 6H, JHH = 7.4 Hz), 7.85
(unresolved multiplet, H-ortho, 12H); alkynyl ligands, 1.72 (m, CH2,
6H), 1.94 (m, CH2, 6H), 1.99 (m, CH2, 6H), 2.17 (m, CH2, 6H), 2.95
(m, CH, 3H). Anal. Calcd for Au3C58CuH58F6P4: C, 42.29; H, 3.55.
Found: C, 42.34; H, 3.58.
Recently we have described a family of tetranuclear AuI−CuI
aryl−alkynyl clusters stabilized by the triphosphine ligand
tris(diphenylphosphino)methane (Chart 1).9
Chart 1. Schematic Representation of Triphosphine AuI−
[HC(PPh2)3Au3Cu(C2But)3]PF6 (3). This complex was prepared using
an alternative method. [HC(PPh2)3Au3Cl3]11 (107 mg, 0.084 mmol)
was suspended in dichloromethane (10 mL). HC2But (21 mg, 0.253
mmol) was added to the suspension followed by mixing with a
solution of [Cu(NCMe)4]PF6 (31 mg, 0.084 mmol) in the same
solvent (5 mL). This mixture was treated with neat Et3N (0.1 mL) to
give a yellow solution, which was stirred for 1 h, and then the solvent
was evaporated. The yellow-green solid was washed with water (3 × 5
mL), methanol (3 × 5 mL), and diethyl ether (2 × 10 mL) and dried
under vacuum. Recrystallization by slow evaporation of an acetone/
heptane solution gave pale yellow-green platelike crystals (105 mg,
78%). ES MS (m/z): [M]+ 1465.20 (calcd 1465.20). 31P{1H} NMR
CuI Alkynyl Clusters
Inspired by the reported difference in photophysical
properties between the compounds bearing aromatic and
aliphatic alkynyl ligands,6b,c we intended to prepare and
systematically investigate the luminescence of structurally
similar AuI−CuI complexes functionalized with aliphatic and
hydroxyaliphatic alkynes having different streric and electronic
parameters. In the present paper we report the synthesis,
structural characterization, and photophysical studies of a series
of heterometallic AuI−CuI complexes, some of which display
distinct switching of luminescence upon exposure to the vapors
of common organic solvents such as acetone, methanol, and
tetrahydrofuran.
1
(CDCl3, 298 K; δ): 40.1 (s, 3P, tppm), −144.1 (sept, 1P, PF6). H
NMR (CDCl3, 298 K; δ): phosphine, 6.21 (unresolved multiplet, H−
CP3, 1H), 7.07 (dd, H-meta, 12H, JHH = 7.4 Hz), 7.17 (t, H-para, 6H,
JHH = 7.4 Hz), 7.85 (unresolved multiplet, H-ortho, 12H); alkynyl
ligands, 1.55 (s, CH3, 18H), 1.57 (s, CH3, 9H). Anal. Calcd for
Au3C55CuH58F6P4: C, 41.00; H, 3.63. Found: C, 41.12; H, 3.69.
[HC(PPh2)3Au3Cu(C2C6H10OH)3]PF6 (4). Single crystals suitable for
X-ray analysis were obtained by slow evaporation of an acetone/
heptane solution of 4 to give yellow platelike crystals (128 mg, 74%).
ES MS (m/z): [M]+ 1591.24 (calcd 1591.23). 31P NMR (CDCl3, 298
−
K; δ): 40.1 (s, 3P), −144.1 (sept, PF6 ). 1H NMR (acetone-d6, 298 K;
δ): phosphine, 6.19 (q, H−CP3, 1H, JPH = 9.7 Hz), 7.12 (dd, H-meta,
12H, JHH = 7.1 Hz), 7.20 (t, H-para, 6H, JHH = 7.1 Hz), 7.86
(unresolved multiplet, H-ortho, 12H); alkynyl ligands, 4.83 (s, OH,
3H), 1.38 (m, CH2, 3H), 1.68−1.96 (m, CH2, 21H), 2.29 (m, CH2,
6H). Anal. Calcd for Au3C61CuH64F6O3P4: C, 42.17; H, 3.71. Found:
C, 42.69; H, 3.86.
EXPERIMENTAL SECTION
■
General Comments. The (AuC2R)n complexes (R = But,
C6H10OH, C5H8OH, C9H18OH, C(CH3)(C3H7)OH, C13H10OH)
were prepared according to the published procedures.6c,e,10 (AuC2Cy)n
and (AuC2Cyp)n acetylides (Cy = cyclohexyl, Cyp = cyclopentyl) were
obtained analogously to (AuC2But)n.10 Tris(diphenylphosphino)-
methane (tppm; Strem Chemicals) and all solvents were used as
received. The solution 1D 1H and 31P NMR and 1H−1H COSY
spectra were recorded on Bruker Avance 400 and Bruker DPX 300
spectrometers. Mass spectra were measured on a Bruker micrOTOF
10223 instrument in the ESI+ mode. Microanalyses were carried out in
the analytical laboratories of St. Petersburg State University and the
University of Eastern Finland.
[HC(PPh2)3Au3Cu(C2C5H8OH)3]CF3SO3 (5). [Cu(CF3SO3)]2·C6H6
was used instead of [Cu(NCMe)4]PF6. The solid obtained was
recrystallized by slow evaporation of an acetone/heptane solution to
give yellow needlelike crystals (110 mg, 65%). ES MS (m/z): [M]+
1
1549.17 (calcd 1549.19). 31P NMR (CDCl3, 298 K; δ): 40.0 (s). H
NMR (CDCl3, 298 K; δ): phosphine, 6.18 (q, H−CP3, 1H, JPH = 9.8
Hz), 7.11 (dd, H-meta, 12H, JHH = 7.3 Hz), 7.18 (t, H-para, 6H, JHH
=
7.3 Hz), 7.85 (unresolved multiplet, H-ortho, 12H); alkynyl ligands,
1.93 (m, CH2, 12H), 2.21 (m, CH2, 6H), 2.32 (m, CH2, 12H), 4.46 (s,
OH, 3H). Anal. Calcd for Au3C59CuH58F3O6P3S: C, 41.70; H, 3.44.
Found: C, 41.77; H, 3.45.
Synthesis of Complexes 1−8. (AuC2R)n (0.3 mmol) was
suspended or dissolved in dichloromethane (15 mL), and a mixture
of tris(diphenylphosphino)methane (tppm, 0.1 mmol) and [Cu-
(NCMe)4]PF6 (0.1 mmol) in the same solvent (5 mL) was added
dropwise. The resulting reaction mixture was stirred for 1 h to give a
transparent solution, which was then filtered and evaporated. The solid
samples obtained were recrystallized as described below.
[HC(PPh2)3Au3Cu(C2C9H18OH)3]PF6 (6). This complex was recrystal-
lized by slow evaporation of a CH2Cl2/hexanes solution to give fine
yellow-green needlelike crystals (134 mg, 72%). ES MS (m/z): [M]+
1723.42 (calcd 1723.42). 31P NMR (acetone-d6, 298 K; δ): 40.2 (s, 3P,
−
tppm), −144.8 (sept, PF6 ). 1H NMR (acetone-d6, 298 K; δ):
phosphine, 6.57 (q, H−CP3, 1H, JPH = 10.0 Hz), 7.18 (dd, H-meta,
12H, JHH = 7.4 Hz), 7.36 (t, H-para, 6H, JHH = 7.4 Hz), 7.93
(unresolved multiplet, H-ortho, 12H); alkynyl ligands, 1.18 (d, CH3,
18H, JHH = 6.7 Hz), 1.24 (d, CH3, 18H, JHH = 6.7 Hz), 1.94 (m, CH/
CH2, 6H), 2.00 (m, CH/CH2, 6H), 2.26 (m, CH/CH2, 6H), 5.24 (s,
OH, 3H). Anal. Calcd for Au3C70CuH88F6O3P4: C, 44.97; H, 4.74.
Found: C, 44.99; H, 4.80.
[HC(PPh2)3Au3Cu(C2Cy)3]PF6 (1). This complex was recrystallized
by slow evaporation of an acetone/heptane/diethyl ether solution to
give pale yellow needlelike crystals (154 mg, 91%). Single crystals
suitable for X-ray analysis were obtained by slow evaporation of a
dichloromethane/hexane solution of 1 at +5 °C. ES MS (m/z): [M]+
1543.25 (calcd 1543.25). 31P NMR (CDCl3, 298 K; δ): 39.7 (s, 3P,
−
tppm), −144.1 (sept, PF6 ). 1H NMR (CDCl3, 298 K; δ): phosphine,
[HC(PPh2)3Au3Cu(C2C(CH3)(C3H7)OH)3]PF6 (7). This complex was
recrystallized by slow evaporation of an acetone/heptane solution to
give yellow-green platelike crystals (112 mg, 66%). Single crystals
suitable for X-ray analysis were obtained by slow evaporation of a
chloroform solution of 7 at +5 °C. ES MS (m/z): [M]+ 1555.24 (calcd
6.13 (q, H−CP3, 1H, JPH = 10.0 Hz), AB2 system 7.10 (dd, H-meta,
12H, JHH = ca. 7 Hz), 7.17 (t, H-para, 6H, JHH = ca. 7 Hz); 7.85
(unresolved multiplet, H-ortho, 12H); alkynyl ligands, 1.43 (m, CH2,
9H), 1.67 (m, CH2, 3H), 1.76 (m, CH2, 6H), 1.92 (m, CH2, 6H), 2.12
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1555.24). 31P NMR (CDCl3, 298 K; δ): 40.0 (s, 3P, tppm), −144.1
data. Structural refinements were carried out using SHELXL-97.13 One
of the cyclohexyl rings (C(20)−C(25)) in 1 and the dichloromethane
crystallization molecule were disordered. However, no suitable
disorder model was found and both geometric and displacement
constraints and restraints were applied to these moieties. Also, carbon
atoms C(20)−C(25), C(1S), and C(7) were restrained so that their
Uij components approximated isotropic behavior.
Some of the solvent molecules in the crystals of 4 and 7 were
omitted, as they were disordered and could not be resolved
unambiguously. The missing solvent was taken into account by
using a SQUEEZE routine of PLATON.16 The contribution of the
solvent to the cell content was not taken into account.
In 9 and 10 both geometric and displacement restraints were
applied to the atoms of disordered acetone crystallization molecules.
The carbon atom C(4) in 9 was restrained so that its Uij components
approximated isotropic behavior. Also, displacement constraints were
applied to the atoms C(4) and C(5) in 9. The OH hydrogen atoms in
7 and 10 were positioned according to the electron density map and
refined with fixed O−H and H···Br distances; Uiso = 1.5Ueq (parent
oxygen atom). All other hydrogen atoms in 1, 4, and 7−10 were
positioned geometrically and were constrained to ride on their parent
atoms, with O−H = 0.84 Å, C−H = 0.95−1.00 Å, and Uiso = (1.2−1.5)
Ueq (parent atom). The crystallographic details are summarized in
Table S1 (Supporting Information).
X-ray powder diffraction analysis was carried out using a Rigaku
Miniflex II (Cu Kα) diffractometer, equipped with a high-speed solid-
state Dtex type detector within the 2θ angle range of 5−50° in the
Bragg−Brentano geometry. The measurements were done with a scan
step 0.02° of 2θ and speed of 2°/min.
Photophysical Measurements. The absolute emission quantum
yields of powders were determined according to the Morse
procedure17 using LED pumping and a diffuse reflectance standard.
The absorption of powders was estimated by measuring diffusion
reflectance and using the Kubelka−Munk theory of light absorption
and scattering of powder layers.18 The vapor-sensitive samples were
exposed to saturated solvent vapor in a sealed vessel for 30 min at
room temperature prior to the corresponding measurements. All
photophysical measurements in solution were carried out in CH2Cl2
that was distilled immediately prior to use. All solutions were carefully
degassed before lifetime and quantum yield measurements. The
absolute emission quantum yield of solution was determined by a
comparative method using LED pumping and rhodamine III in
−
1
(sept, PF6 ). H NMR (CDCl3, 298 K; δ): phosphine, 6.20 (q, H−
CP3, 1H, JPH = 9.8 Hz), AB2 system of H-meta and H-para 7.06−7.25
(unresolved multiplet, 18H), 7.85 (unresolved multiplet, H-ortho,
12H); alkynyl ligands, 1.17−1.39 (unresolved multiplet, CH3, 27H),
2.20 (m, CH, 3H), 4.49 (unresolved multiplet, OH, 3H). Anal. Calcd
for Au3C58CuH64F6O3P4: C, 40.94; H, 3.79. Found: C, 40.99; H, 3.80.
[HC(PPh2)3Au3Cu(C2C13H10OH)3]PF6 (8). A yellow-orange amor-
phous powder was obtained by slow addition of excess pentane to a
dichloromethane solution of 8 (157 mg, 79%). Single crystals suitable
for X-ray analysis were obtained by slow evaporation of a
dichloromethane/methanol solution of 8 at +5 °C. ES MS (m/z):
[M]+ 1843.23 (calcd 1843.24). 31P NMR (acetone-d6, 298 K; δ): 40.1
−
(s, 3P), −144.8 (sept, PF6 ). 1H NMR (acetone-d6, 298 K; δ):
phosphine, 6.62 (q, H−CP3, 1H, JPH = 9.9 Hz), 7.21 (dd, H-meta,
12H, JHH = 7.5 Hz), 7.39 (t, H-para, 6H, JHH = 7.5 Hz), 7.97
(multiplet, H-ortho, 12H, JHH = 7.1 Hz, JPH = 8.2 Hz); alkynyl ligands,
6.18 (s, OH, 3H), 7.25−7.33 (unresolved multiplet, H-meta + H-para,
18H), 7.65 (d, H-ortho, 12H, JHH = 7.7 Hz). Anal. Calcd for
Au3C82CuH64F6O3P4: C, 49.45; H, 3.24. Found: C, 49.35; H, 3.35.
[HC(PPh2)3Au3Cu(C2C13H10OH)3Cl] (9). Method A. CuCl (10 mg,
0.104 mmol) and tris(diphenylphosphino)methane (59 mg, 0.104
mmol) were dissolved in an acetonitrile/dichloromethane mixture (1/
1 v/v, 10 mL), and a solution of AuC2C12H10OH (126 mg, 0.312
mmol) in dichloromethane (5 mL) was added to the mixture. The
nearly colorless reaction mixture was stirred for ca. 1.5 h. The resulting
solution was concentrated to a volume of ca. 5 mL, and slow addition
of acetone caused the formation of a white microcrystalline precipitate
(138 mg, 71%). The amorphous phase of 9 was obtained in the same
way, but the crystallization was provoked by addition of hexane instead
of acetone. Single crystals suitable for X-ray analysis were obtained by
gas-phase diffusion of acetone into a solution of 9 in chloroform at +5
°C.
Method B. 8 (30 mg, 0.015 mmol) was dissolved in acetone (5
mL), and a solution of NBu4Cl (4.5 mg, 0.162 mmol) in the same
solvent (3 mL) was added. The reaction mixture decolorized
immediately, and some white microcrystalline precipitate gradually
formed. The reaction mixture was evaporated and washed with
acetone (3 × 3 mL), and the white crystalline residue was air-dried (25
mg, 87%). ES MS (m/z): [M − Cl−]+ 1843.24 (calcd 1843.24). 31P
1
NMR (CDCl3, 298 K; δ): 43.1 (s, br). H NMR (CDCl3, 298 K; δ):
phosphine, 7.08 (dd, H-meta, 12H, JHH = 7.4 Hz), 7.16 (t, H-para, 6H,
JHH = 7.4 Hz), 8.29 (unresolved multiplet, H-ortho, 12H); alkynyl
ligands, 4.91 (s, OH, 3H), AB2 system centered at 7.24 (H-meta, 12H,
JHH = ca. 7 Hz) and 7.18 (H-para, 12H, JHH = ca. 7 Hz), 7.62 (d, H-
ortho, 12H, JHH = 7.8 Hz). Anal. Calcd for Au3C82H64ClCuO3P3: C,
52.38; H, 3.43. Found: C, 52.29; H, 3.38.
ethanol (Φem = 0.95
0.03) as standard with the refraction
coefficients of dichloromethane and ethanol equal to 1.42 and 1.36,
respectively. An LED (385 nm) was used in the continuous and pulse
modes (pulse width, 1−20 μs; duty of edge, ∼90 ns; repetition rate,
100 Hz to 10 kHz). The absolute luminescence quantum yields for
solid-state samples were determined as described in the Supporting
Information. A Tektronix TDS3014B digital oscilloscope (Tektronix,
band width 100 MHz), MUM monochromator (LOMO, interval of
wavelengths 10 nm) and Hamamatsu photomultiplier tube were used
for lifetime measurements. Emission spectra were recorded using an
HR2000 spectrometer (Ocean Optics). A halogen lamp, LS-1-CAL
(Ocean Optics), and deuterium lamp, DH2000 (Ocean Optics), were
used to calibrate the absolute spectral response of the spectral system
in the 200−1100 nm range. Excitation spectra were measured on a
Varian Cary Eclipse spectrofluorimeter.
[HC(PPh2)3Au3Cu(C2C13H10OH)3Br] (10). This complex was
obtained analogously to 9 (method B) as a white microcrystalline
solid (26 mg, 90%). The amorphous phase of 10 was obtained by
addition of hexane to a concentrated dichloromethane solution of the
complex. Single crystals suitable for X-ray analysis were obtained by
gas-phase diffusion of acetone into a solution of 10 in chloroform at +5
°C. 31P NMR (CDCl3, 298 K; δ): 42.7 (s, br). 1H NMR (CDCl3, 298
K; δ): phosphine, 7.10 (dd, H-meta, 12H, JHH = 7.4 Hz), 7.18 (t, H-
para, 6H, JHH = 6.9 Hz), 8.29 (unresolved multiplet, H-ortho, 12H);
alkynyl ligands, 4.90 (s, OH, 3H), AB2 system centered at: 7.24 (H-
meta, 12H, JHH = ca. 7 Hz) and 7.18 (H-para, 12H, JHH = ca. 7 Hz),
7.62 (d, H-ortho, 12H, JHH = 7.8 Hz). Anal. Calcd for
Au3C82H64BrCuO3P3: C, 51.17; H, 3.35. Found: C, 50.84; H, 3.61.
X-ray Structure Determinations. Crystals of 1, 4, and 7−10
were immersed in cryo-oil, mounted in a nylon loop, and measured at
a temperature of 100 K except for 10, which was measured at 210 K.
The X-ray diffraction data were collected on Bruker Kappa Apex II,
Bruker SMART APEX II, and Bruker Kappa APEX II DUO
diffractometers using Mo Kα radiation (λ = 0.71073 Å). The
APEX212 program package was used for cell refinements and data
reductions. The structures were solved by direct methods using the
SHELXS-9713 programs with the WinGX14 graphical user interface. A
semiempirical absorption correction (SADABS)15 was applied to all
RESULTS AND DISCUSSION
■
Synthesis and Characterization. The synthesis of the
[HC(PPh2)3Au3Cu(C2R)3]+ complexes 1−9 is based on
depolymerization of the homoleptic gold acetylides (AuC2R)n
with the triphosphine ligand HC(PPh2)3 and subsequent
treatment of the reaction mixture with Cu+ ions (Scheme 1,
protocol a). In the case of 3 and 9 an alternative method
reported earlier for the arylacetylene derivatives9a was found to
be more effective (Scheme 1, protocol b).
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a
trend is particularly visible in the clusters with hydroxyaliphatic
alkynes, in each of which the elongated Au(1)−Cu(1)
separations (3.0850(16) and 3.0606(6) Å in 4 and 8,
respectively) point to a considerable weakening of the
metal−metal bond network in this direction. The correspond-
ing Cu(1)−C(2) bond lengths are also noticeably affected by
this structural feature and were found to be 2.215 and 2.200 Å
in 4 and 8, while the Cu(1)−C(4) and Cu(1)−C(6) contacts
do not exceed 2.145 Å. The distortions observed in the
complexes 4 and 8 are very probably caused by intramolecular
O···H−O hydrogen bonding that is clearly evidenced by the
short contacts of the O(1)−O(2) and O(1)−O(3) oxygen
atoms, which lie in the range 2.760−2.893 Å (for details see
Tables S2 and S3 in the Supporting Information).
Scheme 1. Synthesis of the Clusters 1−8
a
Conditions: CH2Cl2, 298 K. Yields: 65−91%.
The ESI-MS of 1−8 display the signals of a singly charged
[HC(PPh2)3Au3Cu(C2R)3]+ cation, the m/z values and
isotopic patterns of which exactly fit the proposed stoichiom-
etry (Figure S2, Supporting Information). The solution NMR
data obtained for 1−8 show that these clusters retain the
structure found in the solid state, which corresponds to the
absence of structural distortions induced by the crystal cell
packing and hydrogen bonding. The latter effect may be
“neutralized” by fast intramolecular scrambling of the alkynyl
ligands involved in the hydrogen-bond network. The 31P{1H}
NMR spectra of 1−8 display singlet resonances of equivalent
phosphorus atoms of the triphosphine ligands in a narrow
range from 39.7 to 41.2 ppm that matches the idealized C3
Clusters 1−6 were characterized using H and 31P NMR
spectroscopy and ESI-MS. The solid-state structures of 1, 4, 7,
and 8 were determined by an X-ray diffraction study (Figure 1
and Figure S1, Supporting Information). However, the poor
diffraction of the crystals of 7 did not allow for high-quality
refinement and the corresponding data are given only in the
Supporting Information. Nevertheless, the structural arrange-
ment of 7 completely fits that revealed for the congeners 1, 4,
and 8. The general motif of these compounds is essentially
similar to that found for closely related clusters bearing alkynyl
ligands with aromatic substituents.9 The complexes 1, 4, and 8
contain a tetranuclear {Au3Cu} metal core stabilized by a
tridentate phosphine. The copper ions in these compounds are
coordinated to three alkynyl CC bonds and additionally
bound to the gold atoms, thus forming a trigonal-pyramidal
metal framework.
1
1
symmetry group of the complexes under study. The H NMR
spectra of 1−8 fit well the structural pattern shown in Scheme 1
and the solid-state structures of 1, 4, 7, and 8. In the low-field
area (6.1−8.0 ppm) these spectra display a typical set of signals
corresponding to the protons of the triphosphine ligandsthe
quartet around 6.1−6.6 ppm is assigned to the CH group of
tppm and the multiplets in the region 7.1−8 ppm are generated
by the protons of the phosphine phenyl rings (see the
Experimental Section and Figures S3−S10 (Supporting
Information)). The high-field group of resonances represents
the aliphatic hydrocarbon substituents of the equivalent
{PAu(C2R)} moieties (except for complex 8, which contains
only aromatic alkynyl substituents). It is has to be noted that in
The Au−Au and Au−Cu distances in the pyramidal fragment
(see the caption to Figure 1) are generally shorter than the sum
of the corresponding of van der Waals radii (3.32 Å for Au−Au
and 3.06 Å for Au−Cu), indicating the presence of effective
metallophilic interactions. The listed bond lengths are not
exceptional and fall in the range found for analogous contacts in
the related bimetallic compounds.6b,c,9a,19 The copper atoms
are bound to the AuC2R moieties in an asymmetric manner
that results in discrimination of the Au−Cu distances. This
Figure 1. Molecular views of the cations of 1, 4, and 8. Counterions and hydrogen atoms are omitted for clarity. Selected interatomic distances
(Å)are as follows. For 1: Au(1)−Au(2) = 3.2657(5), Au(1)−Au(3) = 3.1102(6), Au(2)−Au(3) = 3.2413(6), Au(1)−Cu(1) = 2.8557(14), Au(2)−
Cu(1) = 2.9697(16), Au(3)−Cu(1) = 2.9818(19), C(2)−Cu(1) = 2.170(10), C(4)−Cu(1) = 2.093(16), C(6)−Cu(1) = 2.153(17). For 4: Au(1)−
Au(2) = 3.1319(6), Au(1)−Au(3) = 3.1940(6), Au(2)−Au(3) = 3.2309(6), Au(1)−Cu(1) = 3.0850(16), Au(2)−Cu(1) = 2.9184(15), Au(3)−
Cu(1) = 3.0133(17), Cu(1)−C(2) = 2.215(13), Cu(1)−C(4) = 2.122(12), Cu(1)−C(6) = 2.104(12). For 8: Au(1)−Au(2) = 3.2291(3), Au(1)−
Au(3) = 3.1973(3), Au(2)−Au(3) = 3.1700(3), Au(1)−Cu(1) = 3.0606(6), Au(2)−Cu(1) = 2.9196(9), Au(3)−Cu(1) = 2.8931(8), Cu(1)−C(2) =
2.200(5), Cu(1)−C(4) = 2.145(6), Cu(1)−C(6) = 2.114(6).
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the case of 3 the methyl protons of the −C(CH3)3 fragments
appear as two signals with a 2:1 intensity ratio. This is very
probably caused by the restricted rotation of bulky −C(CH3)3
groups around the C2−C(CH3)3 bond, which however does
not result in loss of the complex total symmetry.
As an extension of the synthetic studies, we modified the
reaction shown in Scheme 1 and used the CuI halides instead of
[Cu(NCMe)4]+ for the preparation of related bimetallic
compounds, as the CuHal salts demonstrate a well-known
affinity toward metal-σ-coordinated alkynyl fragments.20 In-
deed, in the case of an alkynyl ligand with a diphenylmethanolyl
group the halide derivatives of the complex 8 were successfully
isolated as white crystalline materials (Scheme 2). The
considerable distortion of its architecture in comparison to
the cationic congeners 1−8. In these structures only two
alkynyl units are involved in Cu−π-CC bonding with the
values of Cu−C distances falling in the same range as those for
1, 4, and 8. However, in 9 and 10 the shortest distance between
the third Au−CC− moiety and the copper atom (Cu(1)−
C(6)) exceeds 3.45 Å, indicating the absence of an appreciable
interaction. In line with this observation no Au−Cu metal-
lophilic bonds were found in both 9 and 10, as the
corresponding distances are longer than 3.45 Å. The aurophilic
interactions are still retained within the Au3 triangles, as the
Au−Au bond lengths range from 3.0266(4) to 3.2603(7) Å.
These significant structural changes evidently arise from
insertion of the halide ion into the cavity formed by the
alkynyl ligands that also results in substitution of the O···H−O
hydrogen-bonding network for a Hal···H−O network. This is
clearly demonstrated by the values of the Hal···H distances,
which fall in the range 2.4−2.5 Å (for details see Tables S4 and
S5 in the Supporting Information).
a
Scheme 2. Synthesis of the Clusters 9 and 10
The ESI-MS of 9 and 10 are identical with that of 8 and
show the dominating signal of a singly charged [HC-
(PPh2)3Au3Cu(C2C13H10OH)3]+ molecular cation formed
under the conditions of the ESI experiment. The room-
temperature 31P{1H} NMR spectra of 9 and 10 demonstrate a
broadened singlet resonance that is indicative of the
equivalence of all phosphorus atoms. The symmetrization of
the structures found for 10 and 11 in solid state is probably a
result of the fast dynamic process, which involves coordina-
tion−decoordination of the CuHal fragment and its inramo-
lecular “merry-go-round” movement inside the tris-
a
Conditions: (a) CH2Cl2/acetonitrile, 298 K; (b) acetone; 298 K.
Yields: 71−90%.
chloride- and bromide-containing compounds [HC-
(PPh2 )3 Au3 Cu(C2 C1 3 H1 0 OH)3 Cl] (9) and [HC-
(PPh2)3Au3Cu(C2C13H10OH)3Br] (10) were prepared either
through a direct self-assembly in the presence of the CuI salts or
upon treatment of the parent cluster 8 with a stoichiometric
amount of the corresponding tetrabutylammonium halide.
The X-ray crystal structures of the neutral complexes 9 and
10 (Figure 2 and Figure S1 (Supporting Information) for
ORTEP views) were found to keep unchanged the general
structural motif of these tetranuclear clusters. However, it was
revealed that the intact CuHal (Hal = Cl, Br) molecules are
bound to the π systems of the alkynyl ligands, which results in
insertion of the halide ions into the cluster core and
1
(alkynylgold) cluster core. The H NMR spectra also match
well this hypothesis and consist of two groups of signals
corresponding to the aromatic and OH protons of the
equivalent alkynyl ligands and those of the triphosphine phenyl
rings (Figures S11 and S12 in the Supporting Information). In
general the NMR spectral patterns observed for 9 and 10
resemble closely that of the parent cluster 8, which also
indicates higher symmetry of the halide derivatives in solution
in comparison to the solid state.
Photophysical Properties. Solution. All complexes
studied display weak to moderate emission in solution at
room temperature. The spectroscopic and luminescence
characteristics of 1−10 in solution are given in Table 1 and
Figure S13 (Supporting Information). These properties of 1−
10 are similar to those demonstrated by their relatives
containing alkynyl ligands with aromatic substituents.9a The
absorption spectra are determined by the low-energy electronic
transitions (350−450 nm) centered in the cluster core and the
high-energy IL transitions (λ < 350 nm) localized at the alkynyl
and phosphine ligands.9a The complexes show yellow-orange
emission (λem 580−671 nm) with quantum yields in the
0.003−0.046 range. In comparison to 1−10 their Au−Cu close
congeners bearing aromatic alkynes demonstrate systematically
a blue shift of luminescence maxima (560−580 nm) but very
similar quantum efficiencies (0.007−0.034) and lifetimes as
well (1.0−2.8 μs).9b Moreover, the trinuclear Au(I) complexes
[Au3(tppm)Hal3] exhibit similar photophysical characteristic-
s.19a The excited-state lifetimes in the microsecond domain
together with substantial Stokes shifts point to the phosphor-
escent nature of the emission.
Figure 2. Molecular views of complexes 9 and 10. Hydrogen atoms are
omitted for clarity. Selected interatomic distances (Å)are as follows.
For 9: Au(1)−Au(2) = 3.0266(4), Au(1)−Au(3) = 3.2250(4),
Au(2)−Au(3) = 3.1717(4), Cu(1)−Cl(1) = 2.314(2), C(2)−Cu(1)
= 2.101(8), C(3)−Cu(1) = 2.075(8), C(4)−Cu(1) = 2.162(8),
C(5)−Cu(1) = 2.216(7). For 11: Au(1)−Au(2) = 3.0396(7), Au(1)−
Au(3) = 3.2603(7), Au(2)−Au(3) = 3.1950(7), Cu(1)−Br(1) =
2.424(2), C(2)−Cu(1) = 2.151(10), C(3)−Cu(1) = 2.166(12),
C(4)−Cu(1) = 2.187(10), C(5)−Cu(1) = 2.307(11).
Solid State. Much more interesting behavior is observed in
the solid phase, where the luminescence quantum yield is
substantially higher (approaching 60%) and the complexes
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a
Table 1. Photophysical Properties of 1−10 in Solution
λabs, nm (10−3ε,
λem
nm
,
τobs
μs
,
τobs,
c
b
b
c
cm−1 M−1
)
λex, nm
μs
Φ, %
Φ, %
1
2
3
4
296 (21) sh;
319 (14); 388 (1)
332; 397
656
2.3
8.2
1.9
4.0
0.9
0.9
1.1
2.5
2.1
0.6
0.7
0.8
2.0
295 (16) sh;
320 (10); 389 (1)
333; 398
655
2.7
1.6
3.5
314 sh (23); 372 (2) 302; 339; 631
389
297 (22.1) sh;
318 (16.8) sh;
377 (0.8)
305; 335; 579
393
5
296 (31.5) sh;
318 (23) sh;
380 (2)
307; 335
sh; 394
618
4.1
2.5
0.3
0.2
Figure 3. (left) Solid-state absorption and emission spectra of 8 (λex
385 nm; 298 and 77 K). (right) Appearance of 8 under UV excitation
(λex 254 nm).
6
7
8
9
297 (174) sh;
318 (12); 385 (1)
300; 330
sh; 394
580
587
644
644
644
3.5
2.4
5.9
1.9
1.8
2.5
1.5
2.9
1.7
1.5
3.7
1.9
4.6
1.1
1.0
1.8
0.9
2.1
0.9
0.7
296 (15)sh; 317 (12) 302; 333
; 378 (1)
sh; 387
334 sh;
389
296 (19) sh;
317 (14); 382 (1)
296sh (19); 317 (14) 334 sh;
; 382 (1)
10 296 sh (19);
317 (14); 382 (1)
389
334 sh;
389
a
b
Conditions: CH2Cl2, 298 K, λex 385 nm. Degassed solution (average
c
error ca. 5%). Aerated solution (average error ca. 5%).
bearing the alkyne ligand with R = diphenylmethanolyl (8−10)
show distinct vapochromic behavior upon exposure to polar
solvent vapors. The photophysical data for compounds 1−10 in
the solid state are given in Table 2, and the absorption and
emission spectra of complexes 8−10 are given in Figures 3 and
4 and Figure S14 (Supporting Information). The samples of 1−
7 give strong absorption bands at ca. 300 nm and relatively
weak bands in the 350−450 nm range, which may be assigned
Figure 4. (left) Solid-state absorption and emission spectra of 9 (λex
385 nm). (right) Appearance of 9 under UV excitation (λex 254 nm).
The asymmetry of the emission band of THF-treated complex 9 is a
result of incomplete solvation.
to IL and intracore electron transitions analogously to
interpretation of the UV−vis spectra in solution. Similar to
the properties of solution the solid-state samples display a
Stokes shift of ca. 200 nm and excited-state lifetimes in the
microsecond domain. However, the solid-state emission shows
double-exponential decay with substantially higher values of the
lifetimes, which are up to 41 μs in the case of 7. The quantum
yields for unsolvated solids display substantial variations for
different compounds ranging from 0.0265 (complex 3) to 0.48
(complex 6). It is interesting that the complexes bearing alkynyl
ligands without hydroxyl groups as substituents show the
lowest values of quantum yields. A substantial increase in the
emission efficiency for the complexes containing hydroxyal-
kynyl ligands is very probably related to intra- and
intermolecular hydrogen bonding interactions in the solid
state that blocks vibrational nonradiative relaxation of the
excited states.
The emission spectra for complexes 1−11 were also
measured at 77 K (see Table 2 and Figure S14 (Supporting
Information)). All compounds studied display narrowing of the
emission band at 77 K and a relatively small shift of the
emission maxima, which does not exceed 11 nm for the most
complexes, except for 3 and 8c. It is worth noting that in all
cases the low-temperature emission bands are well under the
contour of the room-temperature spectra. This type of behavior
is compatible with the changes in population of vibrational
levels of the ground state and relaxed excited states upon
cooling the systems without variations in the nature of emitting
chromophoric centers.
Table 2. Photophysical Properties of 1−10 in the Solid
a
State
λem, nm
b
λabs, nm
298 K 77 K
τobs(298 K), μs
Φ(298 K), %
1
2
3
4
5
6
7
8
8
8
9
9
9
9
323, 383
335, 430 sh
313, 373 sh
314, 379
316, 390 sh
320, 384
315, 384
317, 374 sh
290, 378
290, 378
320
560
590
597
543
583
546
567
557
501
501
550
480
478
490
550
480
480
491
560
580
546
548
588
540
569
566
476
3.0 (1); 8.4 (0.6)
3.0 (1); 8.4 (0.9)
2.7 (1); 10.2 (0.56)
9 (0.6); 23 (1.0)
20
2.8
2.6
2.5
44
13
48
22
20
60
80
13
5
20 (0.83); 9 (1.0)
41 (1); 21 (0.63)
22.3 (1); 9.6 (0.55)
21
c
d
e
c
f
22
561
24 (1); 9 (0.45)
1.4 (1); 8.5 (0.15)
1.4 (1); 8.5 (0.05)
1.9 (1); 12 (0.2)
20 (1); 6 (0.45)
1.7 (1); 10 (0.1)
1.6 (1); 10 (0.07)
1.8 (1); 12 (0.25)
300
g
h
300
18
12
300
c
10
10
10
10
561
479
e
g
h
293
22
a
Conditions: 25 °C, λex 385 nm. Relative intensities of exponents for
b
the double-exponential decays are given in parentheses. Average error
ca. 10%. Amorphous powder, solvent free. Amorphous powder,
exposed to MeOH. Crystalline solvates with MeOH. Amorphous
c
d
e
f
g
Compounds 8−10 display substantial variation of their
photophysical characteristics upon absorption of polar organic
powder, exposed to acetone. Crystalline solvates with acetone.
h
Amorphous powder, exposed to THF.
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Organometallics
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solvents. For example, treatment of 8 with methanol vapors for
30 min results in a ca. 50 nm hypsochromic shift of absorption
and emission bands and is accompanied by a 3-fold increase of
the luminescence intensity, reaching a value of 60%. The effect
is clearly visible by the naked eye upon irradiation of the
samples with UV light (see Figure 3). It is worth noting that the
short exponent of the emission (τ = 9.6 μs) observed in the
starting sample disappear to leave only a long-lived exponent (τ
= 21 μs). In turn, interaction of the solvent-free samples of 9
and 10 with acetone and THF vapors also gives a
hypsochromic shift of the corresponding emission bands for
60−80 nm (see Figure 4 and Figure S15 (Supporting
Information)) and leads to a substantial drop in the values of
the both short and long exponents of emission decay. It has to
be also noted that crystalline samples obtained from the solvent
mixtures containing methanol, acetone, and THF, respectively,
display nearly identical photophysical characteristics in
comparison to the samples obtained by saturation of the
solvent-free solids with the solvent vapor (see Table 2 and
Figure S14 (Supporting Information)). Unfortunately, the very
high solubility of 8 in acetone and THF prevents observation of
solid-state vapochromism in these particular cases.
Vapochromic behavior was observed for a range of transition-
metal complexes and has been recently reviewed.21 Changes in
the nature and energy of the orbitals responsible for the
emission of the solid-state samples exposed to solvent vapors
(or volatile organic compounds, VOC) stem from very different
reasons, among which the most typical are metal−VOC
bonding,8c,h,22 breaking/formation of metallophilic bonds,7,8f,23
π−π stacking and donor−acceptor bonding24 between VOC
and emitter molecules, hydrogen bonding,25 and, rarely,
reversible isomerization6d,8a,26 induced by the insertion of a
VOC in the crystal lattice. The vapochromic d10 complexes of
the copper subgroup as well as d8 platinum complexes are VOC
responsive mostly due to the variations in intra- or
intermolecular metal−metal distances upon VOC absorption.
In 8 the chromophore center {Cu(AuC2R)3} cluster core seems
to be rather stable and does not demonstrate appreciable
variations in metallophilic bonding in comparison to its
congeners (4−7), which do not display vapochromism and
do not contain polar solvent molecules in the crystal lattices.
However, a clearly visible hydrogen-bonding interaction
between methanol and hydroxyl groups of the alkynyl
substituents was found in the solid state structure (see Figure
S16 in the Supporting Information). This hydrogen bonding is
evidently an electron-withdrawing interaction relative to the
chromophoric center, which lowers the energy of the
corresponding ground-state orbitals and eventually results in
a blue shift of emission in these types of compounds.9a,27
Another particular feature of the vapochromic phases is also
worth noting. The solid phases formed from the solution in the
absence of methanol are X-ray amorphous in contrast to the
crystalline phase obtained from the methanol-containing
solutions. The crystallographic properties of 8 in the solid
state were monitored upon treating the powder with methanol
vapor. Figure 5 shows variations in the X-ray powder diffraction
patterns of cluster 8 before and after exposure to methanol
vapors. The powder obtained from dichloromethane solution
and thoroughly dried in vacuo is X-ray amorphous and displays
weak luminescence with the spectroscopic parameters given in
Table 2 and the spectra shown in Figure 3. This sample was
then subjected to vapors of methanol for 1 h at room
temperature, which results in a slight change of the sample
Figure 5. Powder X-ray diffraction patterns of cluster 8: the solvent-
free powder, the powder treated with MeOH vapors for 1 h, and the
pattern calculated from the single-crystal data.
color and drastic variation in the sample luminescence
parameters (see above). An X-ray powder diffraction study of
the solvated sample shows that reorganization of the solid
occurred to give the crystalline phase, which displays a
diffraction pattern closely analogous to that calculated for the
single-crystal analysis of 8 (Figure 5). The data obtained clearly
indicate that the observed effect of the solvent absorption on
the emission characteristics of the solid phases may be dictated
not only by the intermolecular interaction between isolated
solvent and emitter molecules but also by the far-order
cooperative effects, which distinguish the crystalline and
amorphous solids. This can be of particular importance for
the vapochromism of 9, where an X-ray crystallographic study
did not reveal any significant interaction of the solvent
molecule (acetone) with the chromophoric center (see Figure
S16 in the Supporting Information), which could change the
energy of molecular orbitals responsible for the phosphor-
escence observed. It is also worth noting that an X-ray powder
diffraction study of the acetone absorption by the amorphous
samples of 9 and 10, respectively, display essentially similar
structural transformations (amorphous to crystalline), as
indicated by the diffraction patterns shown in Figure S17
(Supporting Information). Interestingly, complex 8 demon-
strates selectivity to methanol, as ethanol vapors have no effect
on the solid-state emission of the solvent-free sample, pointing
to the inability of ethanol to promote formation of the solvated
crystalline phase due to its different molecular size. This
discrimination between two close homologues is an additional
indication of the solid-state phase transformation, responsible
for the changes in luminescence.
Solvation of the complex 8 is virtually irreversible, as a
prolonged vacuum does not have any appreciable effect on the
properties of the sample treated with MeOH vapors. The
clusters 9 and 10 tend to lose slowly absorbed solvent
molecules. However, complete reversibility could not be
achieved even upon exposure of these compounds to high
vacuum and pure solvent-free systems were not observed.
CONCLUSION
■
A series of heterometallic gold−copper complexes based on
tridentate phosphine and alkynyl ligands with aliphatic and
hydroxyaliphatic substituents was synthesized and structurally
characterized. It was shown that weak interactionsintra-
molecular hydrogen bonding of the hydroxyaliphatic sub-
stituents as well as insertion of halide anionsmay result in
considerable structural distortions of the central heterometallic
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molecular Gold Chemistry; Laguna, A., Ed.; Wiley-VCH: Weinheim,
Germany, 2008; pp 347−402.
cluster core. The compounds obtained display moderate to
weak phosphorescence in solution and considerably higher
triplet emission in the solid state. It was found that the
complexes 8−10 containing an alkyne ligand with R =
diphenylmethanolyl display vapochromic behavior upon
exposure of the solvent-free X-ray amorphous solid samples
to polar VOCs (methanol, THF, acetone). The VOC
absorption results in a visible hypsochromic shift of emission
of 50−70 nm that opens the possibility for the use of these
compounds in VOC sensing devices. The vapochromism
observed may be tentatively ascribed to the formation of a
structurally ordered phase upon absorption of acetone and
THF by an X-ray amorphous solid.
(3) (a) Wei, Q.-H.; Zhang, L.-Y.; Yin, G.-Q.; Shi, L.-X.; Chen, Z.-N. J.
Am. Chem. Soc. 2004, 126, 9940−9941. (b) Crespo, O.; Gimeno, M.
C.; Laguna, A.; Larraz, C.; Villacampa, M. D. Chem. Eur. J. 2007, 13,
235−246. (c) Yu, S.-Y.; Sun, Q.-F.; Lee, T. K.-M.; Cheng, E. C.-C.; Li,
Y.-Z.; Yam, V. W.-W. Angew. Chem., Int. Ed. 2008, 47, 4551−4554.
(d) Qiao, J.; Shi, K.; Wang, Q.-M. Angew. Chem., Int. Ed. 2010, 49,
1765−1767.
(4) Silvestru, C. Gold−Heterometal Interactions and Bonds. In
Modern Supramolecular Gold Chemistry; Laguna, A., Ed.; Wiley-VCH:
Weinheim, Germany, 2008; pp 181−295.
(5) (a) Yip, S.-K.; Chan, C.-L.; Lam, W. H.; Cheung, K.-K.; Yam, V.
W.-W. Photochem. Photobiol. Sci. 2007, 6, 365−371. (b) Koshevoy, I.
O.; Karttunen, A. J.; Tunik, S. P.; Janis, J.; Haukka, M.; Melnikov, A.
̈
S.; Serdobintsev, P. Y.; Pakkanen, T. A. Dalton Trans. 2010, 39, 2676−
ASSOCIATED CONTENT
* Supporting Information
■
2683.
S
(6) (a) Xie, Z.-L.; Wei, Q.-H.; Zhang, L.-Y.; Chen, Z.-N. Inorg. Chem.
Commun. 2007, 10, 1206−1209. (b) Manbeck, G. F.; Brennessel, W.
W.; Stockland, J.; Robert, A.; Eisenberg, R. J. Am. Chem. Soc. 2010,
132, 12307−12318. (c) Koshevoy, I. O.; Lin, C.-L.; Karttunen, A. J.;
Tables, text, figures, and CIF files giving X-ray crystallographic
for 1, 4, and 7−10, ESI-MS spectra of 1−9, and additional
NMR, absorption and emission spectroscopic data. This
material is available free of charge via the Internet at http://
pubs.acs.org.
Janis, J.; Haukka, M.; Tunik, S. P.; Chou, P.-T.; Pakkanen, T. A. Chem.
̈
Eur. J. 2011, 17, 11456−11466. (d) Koshevoy, I. O.; Chang, Y.-C.;
Karttunen, A. J.; Haukka, M.; Pakkanen, T.; Chou, P.-T. J. Am. Chem.
Soc. 2012, 134, 6564−6567. (e) Koshevoy, I. O.; Chang, Y.-C.;
AUTHOR INFORMATION
Corresponding Author
*E-mail: bird231102@mail.ru (E.V.G.), stunik@inbox.ru
(S.P.T.), igor.koshevoy@uef.fi (I.O.K.).
■
Karttunen, A. J.; Selivanov, S. I.; Janis, J.; Haukka, M.; Pakkanen, T. A.;
̈
Tunik, S. P.; Chou, P.-T. Inorg. Chem. 2012, 51, 7392−7403.
(7) Lasanta, T.; Olmos, M. E.; Laguna, A.; Lopez-de-Luzuriaga, J. M.;
Naumov, P. J. Am. Chem. Soc. 2011, 133, 16358−16361.
(8) (a) Cariati, E.; Bu, X.; Ford, P. C. Chem. Mater. 2000, 12, 3385−
3391. (b) Fernandez, E. J.; Lopez-de-Luzuriaga, J. M.; Monge, M.;
Montiel, M.; Olmos, M. E.; Perez, J.; Laguna, A.; Mendizabal, F.;
Mohamed, A. A.; Fackler, J. P. J. Inorg. Chem. 2004, 43, 3573−3581.
(c) Katz, M. J.; Ramnial, T.; Yu, H.-Z.; Leznoff, Daniel B. J. Am. Chem.
Soc. 2008, 130, 10662−10673. (d) Strasser, C. E.; Catalano, V. J. J. Am.
Chem. Soc. 2010, 132, 10009−10011. (e) Laguna, A.; Lasanta, T.;
Lopez-de-Luzuriaga, J. M.; Monge, M.; Naumov, P.; Olmos, M. E. J.
Am. Chem. Soc. 2010, 132, 456−457. (f) Lim, S. H.; Olmstead, M. M.;
Balch, A. L. J. Am. Chem. Soc. 2011, 133, 10229−10238.
(g) Rawashdeh-Omary, M. A.; Rashdan, M. D.; Dharanipathi, S.;
Elbjeirami, O.; Ramesh, P.; Dias, H. V. R. Chem. Commun. 2011, 47,
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We greatly appreciate the financial support of St. Petersburg
State University research grant 12.37.132.2011, the University
of Eastern Finland (strategic funding Russian-Finnish collabo-
rative project and Spearhead project), and the Russian
Foundation for Basic Research grants 11-03-00974, 11-03-
00541. The photophysical experiments were carried out using
scientific equipment of the Center of Shared Usage “The
analytical center of nano- and biotechnologies of SPbSPU” with
the financial support of the Ministry of Education and Science
of the Russian Federation. XRD and NMR studies were
performed at the X-ray Diffraction Centre and the Centre for
Magnetic Resonance of St. Petersburg State University,
respectively.
1160−1162. (h) Lefebvre, J.; Korco
̌
k, J. L.; Katz, M. J.; Leznoff, D. B.
Sensors 2012, 12, 3669−3692.
(9) (a) Shakirova, J. R.; Grachova, E. V.; Gurzhiy, V. V.; Koshevoy, I.
O.; Melnikov, A. S.; Sizova, O. V.; Tunik, S. P.; Laguna, A. Dalton
Trans. 2012, 41, 2941−2949. (b) Shakirova, J. R.; Grachova, E. V.;
Melekhova, A. A.; Krupenya, D. V.; Gurzhiy, V. V.; Karttunen, A. J.;
Koshevoy, I. O.; Melnikov, A. S.; Tunik, S. P. Eur. J. Inorg. Chem. 2012,
4048−4056.
REFERENCES
(10) Coates, G. E.; Parkin, C. J. Chem. Soc. 1962, 3220−3226.
■
(11) Stutzer, A.; Bissinger, P.; Schmidbaur, H. Chem. Ber. 1992, 125,
̈
(1) (a) Zhang, Q.; Zhou, Q.; Cheng, Y.; Wang, L.; Ma, D.; Jing, X.;
Wang, F. Adv. Mater. 2004, 16, 432−436. (b) Che, C.-M.; Lai, S.-W.
Luminescence and Photophysics of Gold Complexes. In Gold
Chemistry; Mohr, F., Ed. Wiley-VCH: Weinheim, Germany, 2009;
pp 249−282. (c) Czerwieniec, R.; Hofbeck, T.; Crespo, O.; Laguna,
A.; Gimeno, M. C.; Yersin, H. Inorg. Chem. 2010, 49, 3764−3767.
(d) Au, V. K.-M.; Wong, K. M.-C.; Tsang, D. P.-K.; Chan, M.-Y.; Zhu,
N.; Yam, V. W.-W. J. Am. Chem. Soc. 2010, 132, 14273−14278.
(e) Czerwieniec, R.; Yu, J.; Yersin, H. Inorg. Chem. 2011, 50, 8293−
8301. (f) Hashimoto, M.; Igawa, S.; Yashima, M.; Kawata, I.; Hoshino,
M.; Osawa, M. J. Am. Chem. Soc. 2011, 133, 10348−10351. (g) He, X.;
Yam, V. W.-W. Coord. Chem. Rev. 2011, 255, 2111−2123. (h) Lu, W.;
Kwok, W.-M.; Ma, C.; Chan, C. T.-L.; Zhu, M.-X.; Che, C.-M. J. Am.
Chem. Soc. 2011, 133, 14120−14135. (i) Hsu, C.-W.; Lin, C.-C.;
Chung, M.-W.; Chi, Y.; Lee, G.-H.; Chou, P.-T.; Chang, C.-H.; Chen,
P.-Y. J. Am. Chem. Soc. 2011, 133, 12085−12099.
367−372.
(12) APEX2 - Software Suite for Crystallographic Programs; Bruker
AXS, Madison, WI, 2009.
(13) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, A64, 112−122.
(14) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837−838.
(15) Sheldrick, G. M. SADABS-2008/1 - Bruker AXS area detector
scaling and absorption correction; Bruker AXS, Madison, WI, 2008.
(16) Spek, A. L. PLATON, A Multipurpose Crystallographic Tool;
Utrecht University, Utrecht, The Netherlands, 2005.
(17) Wrighton, M. S.; Ginley, D. S.; Morse, D. L. J. Phys. Chem. 1974,
78, 2229−2233.
(18) Kubelka, P.; Munk, F. Z. Tech. Phys. 1931, 12, 593−601.
(19) (a) Xiao, H.; Weng, Y.-X.; Wong, W.-T.; Mak, T. C. W.; Che,
C.-M. J. Chem. Soc., Dalton Trans. 1997, 221−226. (b) Bardaji, M.;
Laguna, A.; Jones, P. G.; Fischer, A. K. Inorg. Chem. 2000, 39, 3560−
3566. (c) He, X.; Cheng, E. C.-C.; Zhu, N.; Yam, V. W.-W. Chem.
Commun. 2009, 4016−4018. (d) Tong, G. S. M.; Kui, S. C. F.; Chao,
H.-Y.; Zhu, N.; Che, C.-M. Chem. Eur. J. 2009, 15, 10777−10789.
(2) (a) Fernandez, E. J.; Laguna, A.; Lopez-de-Luzuriaga, J. M. Dalton
Trans. 2007, 1969−1981. (b) Lop
́
ez-de-Luzuriaga, J. M. Luminescence
of Supramolecular Gold-Containing Materials. In Modern Supra-
4068
dx.doi.org/10.1021/om301100v | Organometallics 2013, 32, 4061−4069

Organometallics
Article
(e) Lee, T. K.-M.; Zhu, N.; Yam, V. W.-W. J. Am. Chem. Soc. 2010,
132, 17646−17648.
(20) (a) Abu-Salah, O. M.; Al-Ohaly, A. R. A. J. Chem. Soc., Dalton
Trans. 1988, 2297−2300. (b) Lang, H.; del Villar, A.; Rheinwald, G. J.
Organomet. Chem. 1999, 587, 284−289. (c) Lang, H.; Kocher, S.; Back,
S.; Rheinwald, G.; van Koten, G. Organometallics 2001, 20, 1968−
1972. (d) Fornies, J.; Gomez, J.; Lalinde, E.; Moreno, M. T. Inorg.
Chim. Acta 2008, 347, 145−154. (e) Dietrich, S.; Mansilla, N.;
Hildebrandt, A.; Wetzold, N.; Rheinwald, G.; Ruffer, T.; Lang, H. J.
̈
Organomet. Chem. 2011, 696, 2491−2498.
(21) Zhang, X.; Li, B.; Chen, Z.-H.; Chen, Z.-N. J. Mater. Chem.
2012, 22, 11427−11441.
(22) (a) Albrecht, M.; Lutz, M.; Spek, A. L.; Koten, G. v. Nature
2000, 406, 970−974. (b) Ley, A. N.; Dunaway, L. E.; Brewster, T. P.;
Dembo, M. D.; Harris, T. D.; Baril-Robert, F.; Li, X.; Patterson, H. H.;
Pike, R. D. Chem. Commun. 2010, 4565−4567.
(23) (a) Mansour, M. A.; Connick, W. B.; Lachicotte, R. J.; Gysling,
H. J.; Eisenberg, R. J. Am. Chem. Soc. 1998, 120, 1329−1330. (b) Buss,
C. E.; Mann, K. R. J. Am. Chem. Soc. 2002, 124, 1031−1039. (c) Kato,
M.; Omura, A.; Toshikawa, A.; Kishi, S.; Sugimoto, Y. Angew. Chem.,
Int. Ed. 2002, 41, 3183−3185. (d) Drew, S. M.; Smith, L. I.; McGee, K.
A.; Mann, K. R. Chem. Mater. 2009, 21, 3117−3124. (e) Mo, L.-Q.; Jia,
J.-H.; Sun, L.-j.; Wang, Q.-M. Chem. Commun. 2012, 48, 8691−8693.
(24) (a) Abe, T.; Shinozaki, K. Inorg. Chem. 2005, 44, 849−851.
(b) Abe, T.; Suzuki, T.; Shinozaki, K. Inorg. Chem. 2010, 49, 1794−
1800. (c) Lee, C.-S.; Sabiah, S.; Wang, J.-C.; Hwang, W.-S.; Lin, I. J. B.
Organometallics 2010, 29, 286−289. (d) Lee, C.-S.; Zhuang, R. R.;
Sabiah, S.; Wang, J.-C.; Hwang, W.-S.; Lin, I. J. B. Organometallics
2011, 30, 3897−3900.
(25) (a) Liu, Z.; Bian, Z.; Bian, J.; Li, Z.; Nie, D.; Huang, C. Inorg.
Chem. 2008, 47, 8025−8030. (b) Lu, W.; Chan, M. C. W.; Zhu, N.;
Che, C.-M.; He, Z.; Wong, K.-Y. Chem. Eur. J. 2003, 9, 6155−6166.
(c) Pattacini, R.; Giansante, C.; Ceroni, P.; Maestri, M.; Braunstein, P.
Chem. Eur. J. 2007, 13, 10117−10128.
(26) Li, Y.-J.; Deng, Z.-Y.; Xu, X.-F.; Wu, H.-B.; Cao, Z.-X.; Wang,
Q.-M. Chem. Commun. 2011, 47, 9179−9181.
(27) Koshevoy, I. O.; Lin, Y.-C.; Karttunen, A. J.; Chou, P.-T.;
Vainiotalo, P.; Tunik, S. P.; Haukka, M.; Pakkanen, T. A. Inorg. Chem.
2009, 48, 2094−2102.
4069
dx.doi.org/10.1021/om301100v | Organometallics 2013, 32, 4061−4069