Unexpected formation of a fused double cycle trinuclear gold(i) complex supported by: Ortho -phenyl metallated aryl-diphosphine ligands and strong aurophilic interactions

Article abstract of DOI:10.1039/c6dt01528j

The first homoleptic trinuclear arylgold(i) complex, [Au₃(L′)₂](NO₃) (3), based on an ortho-phenyl metallated aryl-diphosphine ligand (L′ = o-C₆H₄PPh(C₁₅H₁₀O)PPh₂), has been obtained through a new thermolytic reaction of the corresponding diauracycle, [Au₂(L)₂](NO₃)₂ (L = xantphos). The formation of 3 involves activation of the ortho-phenyl C-H bond of the xantphos ligands. The presence of Au-C bonds in this new gold-diphosphine cluster is not its only remarkable feature, since it also displays two 12-membered rings fused together and a linear {Au₃} chain with aurophilic interactions. Complex 3 exhibits strong sky-blue luminescence that can be assigned to a triplet metal-metal (³MM) transition partially mixed with a ligand-to-metal-metal charge transfer (³LMMCT) transition related to the aurophilic bonding. This [Au₃(L′)₂]⁺ triauracycle also shows AIEE-activity, and is a selective luminescent chemosensor for metal ions.

Full text of DOI:10.1039/c6dt01528j

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Unexpected formation of a fused double cycle trinuclear gold(I)
complex supported by ortho-phenyl metallated aryl-diphosphine
ligands and strong aurophilic interactions
Received 00th January 20xx,
Accepted 00th January 20xx
Csaba Jobbágy,a Péter Baranyai,a Pál Szabó,b Tamás Holczbauer,c Barbara Rácz,a Liang Li,d Panče
Naumov*d and Andrea Deák*a
DOI: 10.1039/x0xx00000x
www.rsc.org/
The first homoleptic trinuclear arylgold(I) complex, [Au3(L’)2](NO3) (3), based on ortho-phenyl metallated aryl-diphosphine
ligand (L’ = o-C6H4PPh(C15H10O)PPh2), has been obtained through a new thermolytic reaction of the corresponding
diauracycle, [Au2(L)2](NO3)2 (L = xantphos). The formation of 3 involves the activation of the ortho-phenyl C–H bond of the
xantphos ligands. The presence of the Au−C bonds in this new gold-diphosphine cluster is not its only remarkable feature,
since it also displays two 12-membered rings fused together and a linear {Au3} chain with aurophilic interactions. Complex
3 exhibits strong sky-blue luminescence that can be assigned to triplet metal-metal (3MM) transition partially mixed with
ligand-to-metal-metal charge transfer (3LMMCT) transition related to the aurophilic bonding. This [Au3(L’)2]+ triauracycle
also shows AIEE-activity, and is a selective luminescent chemosensor for metal ions.
stimuli,3 adds a new and important direction to this research.
Recently, we reported that 16-membered diauracycles based
on diphosphine (diphos) ligands, [Au2(diphos)2](X)2, can alter
Introduction
In general, synthetic chemists aim to create new materials
through chemical transformations where chemical bonds
being made or broken. Some of the as-obtained new
compounds often have unusual structures and intriguing
properties. Among metal-based compounds, gold(I) derivatives
with polyphosphine ligands containing gold−phosphorous
bonds are endowed with unconventional structural features
and chemical functionalities.1–5 Gold(I) derivatives are also
attracting interest as functional new materials due to their
exciting potential applications in mechano- and chemosensors,
data recording, nanochemistry and catalysis.1 Yet, the main
inspiration to study these structures comes from their superb
emission properties related to aurophilic interactions.6 One of
the strategies to elicit luminescence by Au···Au contacts relies
upon the use of polyphosphines as connecting units to
generate homoleptic rings.2,3 This approach affords homoleptic
di-, tri- and tetranuclear gold(I) complexes containing only
bridging polyphosphine ligands and short Au···Au contacts.2,3
The possibility of external control of the luminescent
properties of some of these structures by multiple external
their luminescence in response to physical and chemical
stimuli.3 Combining diphosphines with other bridging ligands
such as diacetylides or diisocyanides results in a great diversity
of larger heteroleptic dialkynylgold(I) rings featuring
gold−carbon bonds.4 The presence of alkynylgold(I) units
enhances the photoluminescent properties of these
heteroleptic gold(I) macrocycles.4 Although examples of
homoleptic and heteroleptic rings containing gold(I) centers
are known, preparation of cyclic aryl- or alkylgold(I) complexes
based exclusively on bridging polyphosphine ligands remains a
challenge. The only known example, a pentanuclear gold
cluster that contains a methylene monoaurated diphosphine
ligand,5 was prepared by gold evaporation.7 Along this line of
pursuit, herein we present the first homoleptic trinuclear
arylgold(I) complex that features two ortho-phenyl metallated
diphosphine ligand and shows striking emission properties
both in solution and in solid state. Although some large 16-
and 21-membered macrocycles containing three gold(I)
centres and only diphosphine ligands have been reported,8 this
triauracycle complements these examples with a metallacycle
that consists of two 12-membered rings fused together having
a linear {Au3} chain with short Au···Au contacts and Au−C
bonds. In this communication, we also report the thermally-
induced mechanical effect of crystals of the precursor
diphosphine-based diauracycle that lead to the discovery of
this arylcyclometallated gold(I) complex. This is the first report
on aggregation-induced enhancement emission and metal ion
chemosensing luminescent properties from a diphosphine-
based arylgold(I) system.
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Results and discussion
Our previous studies have shown that the dinuclear gold(I)
complex of the ligand xantphos (L
bis(diphenylphosphino)-xanthene,
=
9,9-dimethyl-4,5-
Ph2P(C15H10O)PPh2),
[Au2(L)2](NO3)2·2.64 CH2Cl2
orange-red in response to mechanical stimuli.3a When heated
from room temperature to 220 °C, crystals of exhibit a
(1) changes its blue emission into
Scheme 1. Thermolysis of 1 followed by recrystallization based on the structure of the
products. Conditions: (i) heating at 180 °C, (ii) washing with toluene and (iii)
recrystallization from dichloromethane-toluene mixture.
1
visually impressive mechanical effect―they hop off the stage
(Movie S1), in a manner that resembles the thermosalient
effect.9 Intrigued by this observation, we investigated the
Single crystal X-ray diffraction analysis of the colourless
products of the thermal decomposition of the crystals of 1. As
crystals of
or the toluene solvates of the dinuclear complex Au2(L)Cl2 (
The structure of the dichloromethane solvate was previously
reported.6a In the toluene:dichloromethane (0.8:0.2) solvate
2
showed that these are either the dichloromethane
shown in Figure 1, bubbles evolve from a crystal which has
been immersed in silicone oil and heated up to 250 °C as a
result of the gas that emanates from the crystal (Movie S2).
Pyrolysis gas chromatography‒mass spectrometry (Py GC‒MS)
showed release of the solvent (CH2Cl2) and NO (Figure S4).
Thus, unlike the thermosalient effect which is due to a phase
2).
2,
the phosphorous atoms of the xantphos ligand bridge the
gold(I) centres, and the distance between them is 2.968(1) Å
(Figure 2). This intramolecular aurophilic interaction, as well as
the bond distances Au–P [2.235(2) Å] and Au−Cl [2.313(2) and
2.295(2) Å] are similar to those found in the dichloromethane
solvate. The gold centres approach a linear P–Au–Cl geometry,
and the corresponding bond angles are 169.9(1) and 173.7(1)°,
respectively. The torsion angles P–Au–Au–P and Cl–Au–Au–Cl
[80.6(1)° and 82.2(1)°] are smaller than those found in
dichloromethane solvate [87.1(1)° and 90.7(1)°]. The dinuclear
transition, the mechanical effect of the crystals of
1 is due to
release of gas, similar to what has been observed with crystals
of nitronyl nitroxide metal complexes.9b
molecules of
2 form C–H···Cl bonded dimers in the crystal of
the toluene solvate.
Figure 1. Optical microscopy image of crystal 1 in 250 °C silicone oil.
The brownish thermolysate of
1 was dissolved in CH2Cl2 and
analysed by electrospray mass spectrometry (ESI-MS). Normal
MS and tandem (MS/MS) spectra (Figures S6−S14) were
recorded in order to identify the structures of species formed.
A representative ESI-MS spectrum (Figure S6) shows the
dissociation of dinuclear [Au2(L)2]2+ cations into mononuclear
[Au(L)]+ species (m/z 775). Oxidation products such as
xantphos dioxide [LO2 + 1H]+ (m/z 611), as well as gold(I)
xantphos oxide (LO) species, [Au(LO)]+ (m/z 791) and
[Au(LO)2]+ (m/z 1385), were also observed. The other
characteristic peaks at m/z 1007, 1565 and 1745 belong to
gold(I) xantphos species (see the discussion below).
Figure 2. Molecular structure of 2. Colour scheme: gold, yellow; phosphorous, orange;
carbon, grey; oxygen, red; chlorine, purple; hydrogen, dark brown. The phenyl groups
are shown as a wireframe model. The solvate molecules are omitted for clarity.
This formation of 2 must involve C–Cl bond activation of CH2Cl2
molecules. Dinuclear [Au2(L)(Cl)]+ species derived upon C–Cl
bond cleavage of dichloromethane were observed in the ESI
MS spectrum at m/z 1007 (Figure S6). While a variety of
dinuclear gold(II) and mononuclear gold(III) compounds were
prepared by gold(I)-mediated oxidative addition of
dichloromethane,10,11 this is a rare observation of formation of
a gold(I) halide complex by activation of the C–Cl bond in
CH2Cl2. Schmidbaur and Fackler studied extensively the
oxidative addition of dihalomethanes CH2X2, halogens X2 (X =
Cl, Br and I) and alkyl halides to eight-membered dinuclear
gold(I) ylide complexes, [Au2(CH2PR2CH2)]2.11 These reactions
occur with one-electron oxidation at each gold centre and
shortening of the Au(II)···Au(II) distance.11 However, it was also
shown that the [Au2(diphos)2]2+ complexes can not oxidatively
add small molecules or easily oxidize.11e,12a Thus, no oxidative
addition of halogens occurred for eight-membered
It appears that the thermolysis of
1 proceeds through a redox
reaction that results in nitrate reduction to NO, oxidation of
the xantphos and formation of complex mixture of products
including several gold(I) species of xantphos and xantphos
oxide. Some more insight into the process of thermolysis was
obtained during the attempts to recrystallize the brownish
thermolysate of
1. Efforts to obtain single crystals were only
successful when the thermolysate of
1
was washed with
toluene, and the remaining brownish solid was dissolved in a
mixture of dichloromethane and toluene. Slow evaporation of
this mixture at 50 °C produced colourless crystals of
2 and
yellow crystals of 3 (Figure S1). The thermolysis of 1 followed
by washing with toluene and recrystallization from
dichloromethane–toluene mixture has been summarized in
Scheme 1.
2 | J. Name., 2012, 00, 1-3
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[Au2(dppm)2]2+ (dppm = Ph2PCH2PPh2) complex.12a In the bonded to phosphorous atoms of the L’ ligands. The Au–P
resulting products, such as [Au2(dppm)2(Br)2], the bromide ions bond lengths are comparable to those found in gold(I)
are coordinated to gold centres, whereas in [Au2(dppm)2(
ꢀ
-
complexes with xantphos.3 The Au–C σ-bond lengths [2.18(1)
I)](I), one iodide bridges the gold centres and the other one is and 2.21(2) Å] are similar to those reported in arylgold(I)
non-coordinated.12a Moreover, it was also reported that the complexes.13 The P–Au–C angles are 164.0(5) and 174.7(3)°,
eight-membered dinuclear [Au2(dcpm)2]2+ complex based on whereas the P–Au–P angle is 161.2(2)°. The P–Au–Au–P
bis(dicyclohexylphosphine)methane (dcpm) is an effective torsion angles, which are 67.2(2) and 71.0(2)° respectively,
photocatalyst for UV-induced C–Cl bond cleavage of CH2Cl2. suggest that the ortho-phenyl aurated xantphos ligands of
The photolysis (irradiation with λ > 260 nm) results in are more folded than the xantphos ligand in . To our
formation of Au2(dcpm)(Cl)2 however the mechanism of knowledge, represents the first structurally characterized
photoconversion is complex and requires further studies.12b In arylcyclometallated gold(I) complex with bridging anionic
our case, as suggested by the Py GC‒MS and ESI-MS data, the diphosphine ligand. Based on structure of , it is also worth
3
2
3
3
nitrate reduction to NO is accompanied by the oxidation of mentioning that only a few instances of gold(I)-mediated C–H
xantphos (L) to xantphos dioxide (LO2). The formation of LO2 activation of arenes has been reported yet.14 Direct C−H
must lead to Au−P bond cleavage and ring opening of 1, which auration with Au(I) compounds specific for electron-poor
would leave the Au(I) centres coordinatively unsaturated. We arenes is believed to proceed via concerted metalation-
propose that the as-formed [Au2L]2+ cationic intermediate deprotonation or deprotonation-metalation mechanisms.14
abstracts Cl– anion from CH2Cl2 to form neutral Au2(L)Cl2
(
2
). Larossa reported that the strong π-coordination ability of
However, the mechanism regarding the activation of C–Cl tBu3PAuCl to arenes lead to direct C–H activation via
-bond
is far from understood and further metathesis and HCl elimination.14a In our case, it should be
σ
bond and formation of
studies are needed.
2
expected that an interconversion between Au2(L)(Cl)2 and
[Au(L)]+ species, both present in the thermolysate, could lead
to the formation of a trinuclear [Au3(L)2(Cl)2]+ intermediate, as
observed in the ESI-MS/MS spectrum (Figure S14). While
detailed mechanistic data are thus far not at hand, we
hypothesize that concerted intramolecular ortho-metalation of
the pendant aryl ring of L of the [Au3(L)2(Cl)2]+ cation followed
by HCl elimination leading to Au−C bond formaꢀon could be a
viable route to the formation of cyclic [Au3(L’)2]+ cation. It is
not yet clear how [Au3(L’)2]+ was formed, since the mixture
was not protected from light a radical mechanism cannot be
ruled out. Moreover, it cannot be ruled out the presence of
catalytic amounts of Au(III) species formed upon oxidative
addition of CH2Cl2, which would also facilitate the C−H bond
activation of pendant aryl ring of the L ligand.
Figure 3. Molecular structure of [Au3(L’)2]+ cation in 3. Colour scheme: gold, yellow;
phosphorous, orange; carbon, grey; oxygen, red; hydrogen, dark brown. The phenyl
groups are shown as a wireframe model. Only the major disorder component is shown.
As shown in Figure S2, the yellow crystals of
3 show intense
bright blue emission when irradiated at 365 nm with UV lamp.
Despite weak X-ray scattering due to a combination of weak
crystallinity, solvation and disorder (see details in SI), the
crystal structure of the yellow crystal of
3 revealed that it
consists of cycloaurated [Au3(L’)2]+ and [Au2(L’)(LO)]+ cations (L’
= o-C6H4PPh(C15H10O)PPh2), in an approximate 60:40 ratio,
NO3– anions and toluene solvent molecules. It should be noted
Figure 4. Two 12-membered Au2P3C6O1 rings fused together, having a {Au3} chain in 3.
Colour scheme: gold, yellow; phosphorous, orange; carbon, grey; oxygen, red.
As shown in Figure 4, the [Au3(L’)2]+ cation consists of two 12-
membered Au2P3C6O1 rings fused together (Figure 4). These
topologically interesting 12-membered rings assume a twisted
conformation, whereas the gold atoms form an almost linear
{Au3} chain (Au···Au···Au angle is 166.9(1)°), with
intramolecular Au···Au contacts of 2.783(2) and 2.850(1) Å,
respectively. Linear {Au3} chains have been found in 12-
membered trigold(I) complexes of bridging triphosphine
ligands.2b Previously, a 16-membered macrocycle containing a
{Au3} triangle has been prepared by employing pyridyl-2,6-
diphenyl2– and bridging diphosphine ligand.15 Laguna reported
some polynuclear gold complexes with linear {Aun} chains (n =
that the ESI-MS spectrum of brownish termolysate of
1 (Figure
S6) showed a peak at m/z 1565 and 1745, characteristic to
monovalent [Au2(L’)(LO)]+ and [Au3(L’)2]+ cation. The trinuclear
cycloaurated [Au3(L’)2]+ cation depicted in Figure 3, with the
disorder omitted for clarity. This [Au3(L’)2]+ cation features two
ortho-phenyl aurated xantphos (L’) ligands, each of which is
P,P,C-coordinated to three gold(I) atoms. This cation displays
an unprecedented coordination mode of the xantphos ligand,
and the ortho-phenyl auration of a diphosphine ligand has
never been observed before. There are two different gold(I)
centres in this biaryl gold(I) cation: Au(1) and Au(3) are bonded
to the phosphorous and carbon atoms, whereas Au(2) is
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3, 5 and 6), wherein the gold atoms are in different oxidation 5b) which exhibits single-exponentional behaviour with a
states.16 For example, the backbone of the tetranuclear lifetime of 180 ns. The emission intensifies when water, an
[Au4(C6F5)2{(Ph2P)2CH}2(Ph3P)2] complex is a linear {Au3} chain anti-solvent of 3, is added (Figure 6a). The emission of 3 in
of four-coordinated gold atoms, which feature either methanol is strongly enhanced between 60 and 80 vol% water
AuII···AuI···AuII or AuI···AuIII···AuI oxidation states.16a Within this (Figure 6b) and in a methanol-water mixture with 80% of
linear {Au3} chain the intramolecular Au···Au contacts are water the luminescence intensity is 20 times that in pure
2.731(2) and 2.909(2) Å, respectively. Among large methanol (Figure 6c). Moreover, we observed that the
macrocycles containing three gold(I) centres and only emission intensity in a methanol-water mixture with 99%
diphosphine ligands,8 our macrocycle represents the first water is lower than that with 90% water. These results indicate
trigold(I) macrocycle that features a linear {Au3} chain with that the intramolecular dynamics of the molecules is restricted
short Au···Au contacts. Further examination of the crystal and the emission of
3
is enhanced by formation of aggregates.
structure of
between the [Au3(L’)2]+ cations and NO3– anions.
The absorption spectrum of in CH2Cl2 shows two intense
3 revealed that there are C–H···O interactions Thus, 3 shows aggregation-induced emission enhancement
(AIEE) activity.17
3
bands in the UV region (Figure 5a). On the basis of DFT
calculations (see details in SI) on the optimized singlet ground
state structure of [Au3(L’)2]+ cation and TDDFT analysis, the
lowest energy absorption band (λ = 356 nm) is assigned to the
transition between the highest occupied molecular orbital and
the lowest unoccupied molecular orbital (HOMO → LUMO, λcalc
= 326 nm, f (oscillator strength) = 0.193; Figure S24, Table S4).
The HOMO is predominantly metal sdσ* character and LUMO
has its major contribution coming from the gold pσ orbitals
and phosphine ligands. Therefore the HOMO
→ LUMO
transition tentatively attributed to the metal-metal-to-ligand-
charge-transfer (MMLCT) transition (Table S5). The absorption
band at 292 nm is assigned to the HOMO – 2 → LUMO + 2
transition (λcalc = 272 nm, f = 0.154; Figure S24, Table S4),
which can be described as π → π* transiꢀon within the
xanthphos ligand (Table S5).
Figure 6. a) Photographs of 3 in methanol-water mixtures (0–99 vol. %) with different
water fractions taken under 365 nm illumination; b) Emission spectra of 3 in methanol-
water mixtures with different water fractions and c) Luminescence intensity of 3 at 480
nm versus the composition methanol-water mixtures (0–99 vol. %).
3
is strongly emissive and emits light with bright blue colour in
the solid state at room temperature with maximum at 480 nm,
which is red shifted by 4 nm at 77 K. The very small difference
between the emission maxima measured in different phases
and the small temperature effect might reflect the structural
rigidity of [Au3(L’)2]+ cations. The decay of luminescence in the
solid state can be described with a monoexponentional
function with lifetimes of 0.9 and 1.8 μs at 298 and 77 K,
respectively. The large Stokes shift and the microsecond
lifetimes indicate that the emission originates from a triplet
state.6a
Figure 5. a) UV/VIS absorption spectra of 3 in CH2Cl2 (10 μM) and b) its emission spectra
in CH2Cl2 solution (solid blue line) and in solid state at room temperature (solid red line)
and at 77 K (dashed red line) upon excitation with 365 nm.
Complex
1 is not luminescent in solution due to the
conformational flexibility of the [Au2(L)2]2+ cation that opens
nonradiative deexcitation channels.3 To attain luminescence in
solution it is necessary to avoid these pathways by sterically
hindering the conformational changes. The linear Au3 chain of
aurophilic interactions and the tridentate μ-bridging of the
xantphos ligands confer enhanced structural rigidity to
cycloaurated
[Au3(L’)2]+
cations
relative
to
the
Figure 7. Contour plots of the HOMO and LUMO superimposed on the excited triplet
(T1) state geometry of [Au3(L’)2]+.
conformationally flexible dinuclear species [Au2(L)2]2+. The
HRMS-ESI spectrum (Figure S3) shows a prominent cluster
peak at m/z 1745 and confirm the existence of trinuclear
To elucidate the luminescence properties of 3, we performed
[Au3(L’)2]+ cations in dichloromethane solution.
3 becomes
quantum chemical calculations on the lowest excited triplet
state (T1) of [Au3(L’)2]+ cation by DFT and TD DFT methods (see
SI for details). The structure for the lowest excited triplet state
weakly emissive at room temperature in deoxygenated CH2Cl2
or MeOH solution with a maximum emission at 480 nm (Figure
4 | J. Name., 2012, 00, 1-3
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(T1) was optimized with the hybrid UPBE018 functional using A methanol solution of
ARTICLE
3
(1 × 10–5 M) is weakly emissive in the
the LANL2DZ effective core potential for the Au centres and absence of metal ions. The luminescence spectrum of
3 in the
the standard 6-31G* basis set for the remaining atoms. In the presence of different metal cations, including Cu2+, Ag+, Hg2+,
optimized geometry of T1 excited state the Au···Au distances Co2+, Ni2+ and Zn2+ at a concentration of 10–3 M, is shown in
are reduced by more than 0.3 Å with increase of the Figure 8b. Ni2+, Zn2+ and Co2+ had little influence on the
Au···Au···Au angle to 177.7°, showing
a
light induced emission intensity (Figure 8b) contrarily Cu2+ cation showed
contraction and linearization of the {Au3} chain (Table S3). strong quenching effect. In case of Hg2+ cation the quenching
According to TD DFT calculation the phosphorescence from T1 of the blue luminescence was delayed, namely the emission
state could be described almost exclusively (orbital completely disappeared after 15 minutes. The addition of Ag+
contribution: 98%, Table S4) as transition between LUMO and to
3 in methanol caused the appearance of a new emission
HOMO (Figure 7). The calculated T1 → S0 emission wavelength band at 577 nm in parallel with an intensity decreasing at 480
(583 nm) for [Au3(L’)2]+ cation predicted by TD DFT method nm, whereas at higher concentration of metal ion both
was greatly overestimated, however the energy difference emission bands were gradually quenched (Figure 8c).
between the highest singly occupied molecular orbital (H-
SOMO) and lowest singly occupied molecular orbital (L-SOMO)
Conclusions
at the optimized T1 geometry provides an emission maximum
at 459 nm,18c which is in good agreement with the
In summary, a homoleptic trinuclear arylgold(I) complex (3)
experimental value measured for blue luminescence of 3. The
featuring two ortho-phenyl aurated diphosphine ligands is
TD DFT and molecular orbital analysis show that the HOMO
and LUMO concentrate mainly on gold atoms and the
contribution of phosphine ligands to the electron density is
smaller in case of HOMO (Figure 7, Table S5). Thus, according
to theoretical calculations the emission can be assigned as
arising from triplet metal centred (3MM) transition mixed with
ligand-to-metal-metal charge transfer (3LMMCT) transition
related to the presence of aurophilic bonding.
reported here that was obtained through a new thermolytic
reaction of a diphosphine-based diauracycle (1), followed by
recrystallization. The as-obtained triauracycle features two 12-
membered rings fused together, which contains a linear {Au3}
chain that shows strong room-temperature luminescence. To
our knowledge, arylcyclometallated Au(I) complexes with
bridging anionic diphosphine ligands have not been reported
yet. The formation of
2 and 3 involves activation of the C–Cl
We tested the luminescence response of
as Cu2+, Ag+, Hg2+, Co2+, Ni2+ and Zn2+. Air-dried filter paper
strips impregnated with a solution of in dichloromethane
3 to metal ions, such
bond of dichloromethane and activation of the aryl C–H bond
of the diphosphine ligands. These C–H and C–Cl bond
activations could be applicable to other relevant gold(I)-
catalyzed chemical processes. Thorough studies on the
mechanism and the exact role of Au(I) in these
transformations are now underway in our laboratory.
3
were treated with few drops of solutions of metal ions. As
shown in Figure 8a, the emission was almost unaffected by
Ni2+ and Zn2+. On the other hand, metal ions such as Co2+ and
Cu2+ significantly quenched the emission, and with Hg2+ the
luminescence was completely quenched. The colour change in
presence of Ag+ ions is particularly striking―upon addiꢀon of
metal ions the sky-blue luminescence changes into strong
greenish-yellow emission (Figure 8a). This visually
Acknowledgments
The authors gratefully acknowledge the support by MTA
(Hungarian Academy of Sciences) through the Lendület
Programme (LP2012-21/2012), part of this research was
carried out using Core Technology Platform resources at New
York University Abu Dhabi (NYUAD).
distinguishable luminescent behaviour of 3 in the presence of
Ag+ ions favours this compound as a sensitive and selective
luminescence sensor for Ag+ ions.
References
1
2
(a) S. L. James, Chem. Soc. Rev., 2009, 38, 1744–1758; (b) M.
J. Irwin, L. M. Rendina, J. J. Vittal and R. J. Puddephatt, Chem.
Commun., 1996, 1281–1282; (c) R. J. Puddephatt, Coord.
Chem. Rev. 2001, 216–217, 313–332; (d) Cs. Jobbágy, A.
Deák, Eur. J. Inorg. Chem. 2014, 4434–4449.
(a) V. W.-W. Yam, T.-F. Lai and C.-M. Che, Dalton Trans.,
1990, 3747–3752; (b) W. Schuh, H. Kopacka, K. Wurst and
P. Peringer, Chem. Commun., 2001, 2186–2187; (c) M.-C.
Brandys and R. J. Puddephatt, Chem. Commun., 2001,
1280–1281; (d) W.-F. Fu, K.-C. Chan, V. M. Miskowski and
C.-M. Che, Angew. Chem. Int. Ed., 1999, 38, 2783–2785; (e)
W.-F. Fu, K.-C. Chan, K.-K. Cheung and C.-M. Che, Chem.
Figure 8. a) Photographs taken under 365 nm UV illumination showing the effect of
different metal ions on the luminescence of 3; b) Emission spectra of 3 in methanol (10
μM) with different metal cations at concentration of 10–3 M and c) Emission spectra of
3 in the presence of increasing concentration of Ag+.
Eur. J., 2001,
V. M. Orera and M. D. Villacampa, Inorg. Chem., 1998, 37
5125–5130; (i) G. S. M. Tong, S. C. F. Kui, H.-Y. Chao, N. Zhu
and C.-M. Che, Chem. Eur. J., 2009, 15, 10777–10789; (j) Y.
7, 4656–4664; (f) (g) (h) M. Bardají, A. Laguna,
,
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Page 6 of 7
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ARTICLE
Journal Name
Takemura, H. Takenaka, T. Nakajima and T. Tanase, Angew. 15 S. C. F. Kui, J.-S. Huang, R. W.-Y. Sun, N. Zhu and C.-M. Che,
Chem. Int. Ed., 2009, 48, 2157–2161. Angew. Chem. Int. Ed., 2006, 45, 4663–4666.
(a) A. Deák, T. Megyes, G. Tárkányi, P. Király, L. Biczók, G. 16 (a) M. C. Gimeno, J. Jiménez, P. G. Jones, A. Laguna and M.
3
Pálinkás and P. J. Stang, J. Am. Chem. Soc., 2006, 128, 12668–
12670; (b) T. Tunyogi, A. Deák, G. Tárkányi, P. Király and G.
Pálinkás, Inorg. Chem., 2008, 47, 2049–2055; (c) A. Deák, T.
Tunyogi, Z. Károly, Sz. Klébert and G. Pálinkás, J. Am. Chem.
Laguna, Organomet., 1994, 13, 2508–2511; (b) A. Laguna, M.
Laguna, J. Jiménez, F. J. Lahoz, E. Olmos, Organomet., 1994,
13, 253–257; (c) R. Usón, A. Laguna, M. Laguna, J. Jiménez, P.
G. Jones, Angew. Chem. Int. Ed., 1991, 30, 198–199.
Soc., 2010, 132, 13627–13629; (d) Cs. Jobbágy, M. Molnár, P. 17 J. Mei, N. L. C. Leung, R. T. K. Kwok, J. W. Y. Lam and B. Z.
Baranyai, A. Hamza, G. Pálinkás and A. Deák, CrystEngComm, Tang, Chem. Rev., 2015, 115, 11718–11940.
2014, 16, 3192–3202; (e) Cs. Jobbágy, M. Molnár, P. Baranyai 18 (a) W. Lu, K. T. Chan, S.-X. Wu, Y. Chen and C.-M. Che, Chem.
and A. Deák, Dalton Trans., 2014, 43, 11807–11810; (f) A.
Deák, Cs. Jobbágy, G. Marsi, M. Molnár, Z. Szakács and P.
Baranyai, Chem. Eur. J., 2015, 21, 11495–11508; (g) P.
Baranyai, G. Marsi, Cs. Jobbágy, A. Domján, L. Oláh and A.
Deák, Dalton Trans., 2015, 44, 13455–13459;
Sci., 2012, 3, 752-755; (b) G. S. M. Tong, K. T. Chan, X. Chang
and C.-M. Che, Chem. Sci., 2015, 6, 3026-3037; (c) G.
Chakkaradhari, Y.-T. Chen, A. J. Karttunen, M. T. Dau, J. Jänis,
S. P. Tunik, P.-T. Chou, M.-L. Ho and I. O. Koshevoy, Inorg.
Chem., 2016, 55, 2174–2184.
4
(a) C. P. McArdle, M. J. Irwin, M. C. Jennings, J. J. Vittal and R.
J. Puddephatt, Chem. Eur. J., 2002, 8, 723–734; (b) W. J.
Hunks, J. Lapierre, H. A. Jenkins and R. J. Puddephatt, Dalton
Trans., 2002, 2885–2889; (c) W. J. Hunks, M.-A. MacDonald,
M. C. Jennings and R. J. Puddephatt, Organomet., 2000, 19
,
5063–5070; (d) V. W.-W. Yam, S. W.-K. Choi and K.-K.
Cheung, Organomet., 1996, 15, 1734–1739.
5
6
J. W. A. van der Velden, J. J. Bour, F. A. Vollenbroek, P. T.
Beurkens and J. M. M. Smits, Chem. Commun., 1979, 1162–
1163.
(a) A. Pintado-Alba, H. de la Riva, M. Nieuwhuyzen, D.
Bautista, P. R. Raithby, H. A. Sparkes, S. J. Teat, J. M. López-
de-Luzuriaga and M. C. Lagunas, Dalton Trans., 2004, 3459–
3467; (b) M. A. Rawashdeh-Omary, J. M. López-de-Luziriaga,
M. D. Rashdan, O. Elbjeirami, M. Monge, M. Rodríguez-
Castillo and A. Laguna, J. Am. Chem. Soc., 2009, 131, 3824–
3825; (c) H. Ito, M. Muromoto, S. Kurenuma, S. Ishizaka, N.
Kitamara, H. Sato and T. Seki, Nat. Commun., 2013, 4, 2009;
(d) T. Seki, K. Sukurada and H. Ito, Angew. Chem. Int. Ed.,
2013, 52, 12828–12832.
F. A. Vollenbroek, P. C. P. Bouten, J. M. Trooster, J. P. van
7
8
den Berg and J. J. Bour, Inorg. Chem., 1978, 5, 1345–1347.
(a) S. Bhargava, K. Kitadai, T. Masashi, D. W. Drumm, S. P.
Russo, V. W.-W. Yam, T. K.-M. Lee, J. Wagler and N.
Mirzadeh, Dalton Trans., 2012, 41, 4789–4798; (b) J. H. K. Yip
and J. Prabhavathy, Angew. Chem. Int. Ed., 2001, 40, 2159–
2162.
9
(a) P. Naumov, S. Chizhik, M. K. Panda, N. K. Nath and E.
Boldyreva, Chem. Rev., 2015, 115, 12440−12490; (b) V. I.
Ovcharenko, S. V. Fokin, E. Y. Fursova, O. V. Kuznetsova, E. V.
Tretyakov, G. V. Romanenko and A. S. Bogomyakov, Inorg.
Chem., 2011, 50, 4307–4312.
10 D. Aguilar, M. Contel and E. P. Urriolabeitia, Chem. Eur. J.,
2010, 16, 9287–9296.
11 (a) P. Jandik, U. Schubert and H. Schmidbaur, Angew. Chem.
Int. Ed., 1982, 21, 73; (b) H. Schmidbaur and P. Jandik, Inorg.
Chim. Acta, 1983, 74, 97–99; (c) J. P. Fackler and J. D. Basil,
Organomet., 1982,
and A. M. Mazany, Organomet., 1984,
Fackler, Polyhedron, 1997, 16, 1–17; (f) A. Laguna and M.
Laguna, Coord. Chem. Rev., 1999, 193 195, 837–856.
12 (a) J. Shain and J. P. Fackler, Inorg. Chim. Acta, 1987, 131
1
, 871–873; (d) H. H. Murray, J. P. Fackler
3, 1310–1311; (e) J. P.
–
,
157–158; (b) C. Ma, C. T.-L. Chan, W.-P. To, W.-M. Kwok and
C.-M. Che, Chem. Eur. J., 2015, 21, 13888–13893.
13 (a) D. V. Partyka, J. B. Updegraff III, M. Zeller, A. D. Hunter
and T. G. Gray, Organomet., 2009, 28, 1666–1674; (b) C.
Croix, A. Balland-Longeau, H. Allouchi, M. Giorgi, A. Duchêne
and J. Thibonnet, J. Organomet. Chem., 2005, 690, 4835–
4843.
14 (a) P. Lu, T. C. Boorman, A. M. Z. Slawin and I. Larrosa, J. Am.
Chem. Soc., 2010, 132, 5580–5581; (b) X. C. Cambeiro, N.
Ahlsten and I. Larrosa, J. Am. Chem. Soc., 2015, 137, 15636–
15639.
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