Low-Nuclearity Alkynyl d10 Clusters Supported by Chelating Multidentate Phosphines

Article abstract of DOI:10.1021/acs.organomet.6b00701

The coordination chemistry of the tri- and tetradentate chelating phosphines (2-PPh₂C₆H₄)₂P(O)Ph (P³O) and (2-PPh₂C₆H₄)₃P (P⁴) with respect to d¹⁰ copper subgroup metal ions has been investigated. Depolymerization of (MC₂R)_n (M = Cu, Ag) with P⁴ affords the series of mono- and trinuclear complexes (P⁴)CuC₂Ph (1), (P⁴)Cu₃(C₂Ph)₃ (2), (P⁴)Ag₃(C₂Ph) (Hal)₂ (Hal = Cl (3), Br (4), I (5)). Reactions of the M⁺ (M = Cu, Ag) ions with (M′C₂R)_n (M′ = Cu, Ag, Au) acetylides in the presence of P⁴ yield the family of dinuclear species [(P⁴)MM′(C₂R)]⁺ (6-12), which comprise the Cu₂/Ag₂ (6, 7; R = Ph), AuCu (8-10; R = Ph, C(OH)Me₂, C(OH)Ph₂), and AuAg (11, 12; R = Ph, C(OH)Ph₂) metal cores. A related triphosphine, (2-PPh₂C₆H₄)₂PPh (P³), applied in a similar protocol undergoes partial oxidation and leads to the heterotrimetallic clusters [{(P³O)M}₂Au(C₂R)₂]⁺ (M = Cu, R = C(OH)Ph₂, 13; M = Ag, R = C(OH)Ph₂, 14; M = Ag, R = Ph, 15), which can be prepared more efficiently starting from the oxidized ligand P³O. The structures of the complexes 1-4 and 6-15 were established by single-crystal X-ray crystallography. According to the variable-temperature ¹H and ³¹P{¹H} NMR experiments, compounds 1-12 demonstrate fluxional behavior in solution. The title complexes do not show appreciable luminescence in solution at 298 K, and the photophysical properties of 1-15 were studied in the solid state. The observed phosphorescence (_em up to 0.46, λ_em from 440 to 635 nm) is assigned to cluster-centered transitions mixed with some MLCT d →π^?(alkynyl) character.

Full text of DOI:10.1021/acs.organomet.6b00701

Article
pubs.acs.org/Organometallics
Low-Nuclearity Alkynyl d10 Clusters Supported by Chelating
Multidentate Phosphines
Andrey Belyaev,† Thuy Minh Dau,† Janne Janis,† Elena V. Grachova,‡ Sergey P. Tunik,*,‡
̈
and Igor O. Koshevoy*,†
†Department of Chemistry, University of Eastern Finland, Joensuu, 80101, Finland
‡St. Petersburg State University, 7/9 Universitetskaya nab., 199034 St. Petersburg, Russia
S
* Supporting Information
ABSTRACT: The coordination chemistry of the tri- and
tetradentate chelating phosphines (2-PPh2C6H4)2P(O)Ph
(P3O) and (2-PPh2C6H4)3P (P4) with respect to d10 copper
subgroup metal ions has been investigated. Depolymerization
of (MC2R)n (M = Cu, Ag) with P4 affords the series of mono-
and trinuclear complexes (P4)CuC2Ph (1), (P4)Cu3(C2Ph)3
(2), (P4)Ag3(C2Ph) (Hal)2 (Hal = Cl (3), Br (4), I (5)).
Reactions of the M+ (M = Cu, Ag) ions with (M′C2R)n (M′ =
Cu, Ag, Au) acetylides in the presence of P4 yield the family of
dinuclear species [(P4)MM′(C2R)]+ (6−12), which comprise
the Cu2/Ag2 (6, 7; R = Ph), AuCu (8−10; R = Ph,
C(OH)Me2, C(OH)Ph2), and AuAg (11, 12; R = Ph,
C(OH)Ph2) metal cores. A related triphosphine, (2-
PPh2C6H4)2PPh (P3), applied in a similar protocol undergoes partial oxidation and leads to the heterotrimetallic clusters
[{(P3O)M}2Au(C2R)2]+ (M = Cu, R = C(OH)Ph2, 13; M = Ag, R = C(OH)Ph2, 14; M = Ag, R = Ph, 15), which can be
prepared more efficiently starting from the oxidized ligand P3O. The structures of the complexes 1−4 and 6−15 were established
1
by single-crystal X-ray crystallography. According to the variable-temperature H and 31P{1H} NMR experiments, compounds
1−12 demonstrate fluxional behavior in solution. The title complexes do not show appreciable luminescence in solution at 298
K, and the photophysical properties of 1−15 were studied in the solid state. The observed phosphorescence (Φem up to 0.46, λem
from 440 to 635 nm) is assigned to cluster-centered transitions mixed with some MLCT d → π*(alkynyl) character.
photofunctional compounds and materials comprising combi-
nations of d8 (PtII) and d10 metal (CuI, AgI, AuI) ions.8
INTRODUCTION
■
Metal−metal bonds represent unique types of interactions that
have been extensively used for the construction of numerous
multimetallic compounds. The availability of single-crystal
diffraction analysis as a routine method of structural character-
ization made possible careful analysis of the M−M noncovalent
bonding and, consequently, rational and predictable supra-
molecular design of sophisticated metal-containing architec-
tures.1 The presence of several metal ions or atoms in one
molecular entity often brings a distinct cooperative effect and
leads to the emergence of physical and chemical properties
which cannot be accessed by a simple combination of the
monometallic components.2 Such synergistic functionality has
significantly driven the experimental and theoretical efforts that
have impressively advanced the fundamental chemistry of
metal-rich aggregates (clusters and nanoparticles), which have
also been applied in catalysis,3 fabrication of photonic devices,4
visualization,5 and detection techniques.6 In this respect,
particular interest has been paid to closed-shell attractive
forces, for which the general term “metallophilicity” was
Due to the relative weakness of d10−d10 metallophilic bonds,
which are comparable in strength to hydrogen bonds (ca. 15−
40 kJ/mol),7,9 an additional stabilization of the polymetallic
assemblies is often required. This goal can be achieved (a) in a
spontaneous manner by forming an extended network of M−M
interactions leading to high-nuclearity clusters and polymers1f,10
and (b) by using appropriate (element)-organic bridging
ligands, which support effective contact between the metal
atoms and simultaneously provide a way to control the
geometry of the resulting frameworks on the molecular level.1f,g
The choice of ligand environment is largely dictated by the
affinity of the binding groups to the particular metal ions in
given oxidation states. The anionic alkynyl ligands serve as
popular building blocks for the preparation of d10 coinage-metal
clusters primarily due to a pronounced tendency of the −C
CR moiety to coordinate in a few σ,π-bridging modes and
therefore to support the metallophilic interactions.3c,10a,c,11
Tertiary phosphines as ancillary soft donors are also frequently
proposed by Pyykko.7 These metal−metal interactions
suggested remarkably rich opportunities for the design of
̈
Received: September 3, 2016
© XXXX American Chemical Society
A
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utilized as bridging ligands and have no less important influence
on the arrangement of the metal core and, consequently, on the
physical properties of the cluster complexes. Analysis of the
structurally characterized d10 polymetallic Mx (M = Cu, Ag, Au;
x ≥ 2) alkynyl phosphine compounds permits distinguishing
three main synthetic strategies depending on the denticity and
stereochemistry of the templating phosphine ligands (Chart 1).
prevent their dissociation in solution. However, chelating
phosphines have been predominantly used for the synthesis of
monometallic coordination d10 compounds but not for that of
alkynyl complexes with metallophilic bonding, as there are only
a few examples17 with very scarce photophysical data.18
In the present contribution, we demonstrate the so far poorly
explored possibility of utilizing oligodentate chelating phos-
phine ligands for the preparation of low-nuclearity luminescent
complexes of CuI, AgI, and AuI. We have systematically
synthesized a series of di- and trinuclear homo- and
heterometallic alkynyl compounds and carried out structural
and photophysical studies to correlate the luminescence
behavior with the molecular structures of the novel species.
Chart 1. Three Types of d10 Coinage-Metal Alkynyl-
Phosphine Clusters
RESULTS AND DISCUSSION
■
Homometallic Neutral Complexes. The tetradentate
phosphine (2-PPh2C6H4)3P (P4) readily reacts with polymeric
copper phenylacetylide, (CuC2Ph)n, in s 1:1 molar ratio to give
the yellow mononuclear complex (P4)CuC2Ph (1) in high yield
(Scheme 1). Using the same reagents in a 1:3 stoichiometry
affords the trinuclear cluster (P4)Cu3(C2Ph)3 (2) in a moderate
yield due to the formation of appreciable amounts of 1 as a side
product. Attempts to prepare analogous silver compounds were
unsuccessful, and only the trinuclear chloride-alkynyl cluster
(P4)Ag3(C2Ph)Cl2 (3) could be isolated from a reaction carried
out in dichloromethane. Complex 3 is obviously generated as a
result of halide subtraction from the solvent. Using a
nonchlorinated medium did not allow us to obtain the
alkynyl-only silver complexes with a P4 ligand, presumably
because of their intrinsic instability.
Optimization of the reaction conditions of the synthesis of 3
(Scheme 2) that involve utilization of a 1:2 molar mixture of
(AgC2Ph)n/AgCl as starting reagent improved the yield and
permitted the synthesis of bromide (4) and iodide (5)
homologues of 3. It has to be noted that the P4 ligand has
virtually not been used for the synthesis of copper subgroup
metal compounds, with only one example of [(P4)Cu]BF4
described to date.19
In the type A clusters a homoleptic alkynyl core is supported by
the external shell of di-/triphosphines with substantial spatial
separation of the PR2R′ coordinating functions.4c,12 For the B
species ligands with short spacers (bis(diphenylphosphino)-
methane and related bi- and tridentate phosphines with similar
geometry) providing intermetallic distances in the range 2.8−
3.4 Å are used on a periphery of metal−alkynyl frame-
works.4d,13
The A and B approaches often produce medium- to high-
nuclearity compounds, which exhibit intense luminescence. In
the case of monophosphine-stabilized clusters (C) a minimal
assembly of two metal centers occurs under favorable
conditions rendered by the ligand sphere,14 though formation
of larger species cannot be excluded.15 The former compounds
were shown to be useful in homogeneous catalysis because of
their lability and thus easy generation of active species.16
To increase the kinetic and photodynamic stability of low-
nuclearity complexes, it seemed feasible to employ chelating
oligophosphines, which are capable of saturating the coordina-
tion vacancies of the constituting metal ions and concurrently
Complexes 1−4 have been characterized crystallographically
(Figure 1 and Figure S1 in the Supporting Information;
selected bond lengths are given in Table S2 in the Supporting
Information). In the monometallic 1 the P4 phosphine is
Scheme 1. Synthesis of Complexes 1−5
B
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a
distances of 3.127−3.291 Å that significantly exceed the
conventional interval of P−Ag bonds.
Scheme 2. Synthesis of Complexes 6−12
The NMR spectroscopic data for compounds 1−5 are
generally consistent with the solid-state structures, which are
retained in solution, though they appear to be stereochemically
nonrigid in fluid medium (see the Experimental Section and
Table S5 in the Supporting Information for the 31P{1H} NMR
spectroscopic parameters). The 31P NMR spectrum of complex
1 at 298 K displays two resonances with a 3:1 ratio of relative
intensities (Figure S2 in the Supporting Information) that
points to the equivalence of the terminal PPh2 groups due to
their fast exchange. Cooling the sample to 193 K slows down
the dynamic process and causes the appearance of three signals
of 2:1:1 integral intensities, one of which is considerably shifted
to a high-field region (−24.5 ppm) and obviously corresponds
to the noncoordinated PPh2 arm. Copper cluster 2
demonstrates the expected 31P NMR pattern with two
multiplets at −10.8 (d, 3PPh2) and −14.6 ppm (q,
P(C6H4PPh2)3), broadened at 298 K. Lowering the temper-
ature to 193 K does not change the number of signals and their
multiplicity, which suggest a symmetrical coordination of the P4
phosphine on the Cu3 core.
The phosphorus NMR spectra of 3−5 are very much alike
(Figure S3 in the Supporting Information), each of which
displays a low-field doublet (−5.4 to −6.8 ppm) accompanied
by a high-field unresolved multiplet (−33.0 to −33.9 ppm),
assigned to PPh2 and P(C6H4PPh2)3 fragments, respectively, on
the basis of the relative intensities. The presence of only one
signal arising from terminal diphenylphosphine groups and the
absence of detectable 31P−107,109Ag couplings can be explained
in terms of fast intramolecular dynamics, tentatively ascribed to
a merry-go-round rotation of the tetraphosphine over the Ag3
coordinating framework. Attempts to freeze this motion were
not completely successful, as even at 183 K the 31P NMR
pattern remains complicated and hardly interpretable presum-
ably due to the presence of several forms.
a
Conditions: CH2Cl2/acetone, 2 h, 298 K.
coordinated to the metal center in a tridentate mode, thus
having one pendant −PPh2 group with a P(3)−Cu(1)
separation of 3.958 Å. Together with the σ-bound −CCPh
moiety the ligand sphere saturates four coordination vacancies
of the copper ion, which adopts a distorted-tetrahedral
geometry in a fashion similar to that of (P3)CuC2R compounds
(P3 = (PPh2C6H4)2PPh) reported recently.20
Nearly equilateral triangular cores are found in the M3
clusters 2−4; the metal−metal distances are comparable to
the corresponding values determined for other copper12a,15c,21
and silver21c,22 alkynyl compounds that are indicative of
effective metallophilic interactions. The metal−metal bonds
are additionally supported by the μ2,σ-bridging alkynyl (2−4)
and halide (3, 4) ligands, which are located on the edges of the
trimetallic triangles. The tetraphosphine ligand in 2−4 occupies
a capping position over the cluster framework. Each of the
terminal PPh2 groups is coordinated to the metal vertex, thus
bridging all metal−metal contacts; the M−PPh2 bond lengths
(2.132−2.225 Å for Cu−P and 2.378−2.418 Å for Ag−P) are
slightly shorter than those in 1 but are within the normal range
reported for the congener species.12a,15c,21,22,22d However, the
central phosphorus atom P(2) of the P4 ligand is only poorly
involved in binding to the metal ions, as the shortest
separations P(2)−M are 2.723 and 2.883 Å for 2 and 3,
respectively. Moreover, in cluster 4 the P(2) donor is placed
roughly over the center of the Ag3 skeleton with P(2)−Ag
The 1H NMR data are also compatible with the composition
and structure of the complexes 1−5 found in the solid state.
However, because of the fluxionality of these species and the
presence of similar aromatic protons, the signals of which
appear in a quite narrow region, these spectra are insufficiently
resolved and therefore are much less informative than the data
of 31P NMR measurements.
Homo- and Heterometallic Cationic Complexes. The
availability of a noncoordinated −PPh2 function in complex 1
Figure 1. Molecular views of complexes 1, 2, and 4. Thermal ellipsoids are shown at the 50% probability level. H atoms are omitted for clarity.
C
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Figure 2. Molecular views of complexes 6, 7, and 12. Thermal ellipsoids are shown at the 50% probability level. Counterions and H atoms are
omitted for clarity. Symmetry transformations used to generate equivalent atoms in 7: (′) 2 − x, 2 − y, 1 − z.
prompted us to investigate the possibility of its binding to
another metal center using different combinations of d10 ions.
For this purpose, the phosphine P4 was coupled with a
stoichiometric amount of the suitable polymeric phenyl-
acetylide (MC2R)n (M = Cu, Ag, Au), followed by the addition
of AgPF6 or Cu(NCMe)4PF6 salt to produce a series of
dinuclear cationic compounds 6−12 of the general formula
[(P4)MM′(C2R)]PF6 (Scheme 2).
The solid-state structures of all complexes 6−12 have been
determined by XRD analysis; see Figure 2 and Figure S4 in the
Supporting Information. These species adopt a similar
structural motif (except 7), in which a bimetallic unit MM′ is
supported by the P4 phosphine and the σ,π-bridging
coordination of the CCR fragment. One metal center having
a σ-bonded alkynyl ligand is connected to the P(1) donor of a
PPh2 arm and therefore is found in a formally two-coordinate
environment. The second d10 ion is chelated by the remaining
three phosphorus atoms of the P4 ligand and is additionally
linked to the π system of the CC triple bond to attain a
pseudotetrahedral geometry. The metal−metal distances found
in 6−12 (Table S3 in the Supporting Information) are normal
for the Cu−Cu,12a,15c,21 Ag−Ag,21c,22 Au−Cu,12b,13e,23 and Au−
Ag4c,12c,g interactions observed for the corresponding alkynyl
compounds, indicating the presence of effective metallophilic
bonding in the title species. The coordination of alkynes in 6−
12 is also not exceptional, and the related structural parameters
correlate well with previous reports.4c,12b,c,g,13e,23
ligands in 7 have μ3-η1,η1,η2-bridging positions, which have
been observed in high-nuclearity silver clusters and polymers.24
Electrospray ionization mass spectrometry (ESI-MS) meas-
urements, however, did not detect the presence of the
dicationic [{(P4)Ag2(C2Ph)}2]2+ molecular form of 7 (Figure
S5 in the Supporting Information) and show only the signal at
m/z 1129.08 of the monocation, pointing to a possible
dissociation of 7 into the bimetallic [(P4)Ag2(C2Ph)]+ units,
which are analogous to other dinuclear complexes of types 6−
12. For the rest of these clusters the results of ESI-MS studies
are completely compatible with compositions found in the solid
state and display the dominant signals at m/z 1041.14 (6),
1175.18 (8), 1157.19 (9), 1281.22 (10), 1219.15 (11), and
1325.20 (12); the isotopic distributions match well the
calculated patterns (Figure S5).
The room-temperature 31P NMR spectra of 6 and 7 indicate
that these homometallic complexes demonstrate intramolecular
fluxionality in solution. At 298 K the copper compound 6
shows a low-field multiplet centered at −9.5 ppm and a very
broad unresolved bump in the range from 5 to −4 ppm (Figure
S6 in the Supporting Information). The spectroscopic pattern
becomes clearly interpretable at 193 K, with all PPh2 groups of
the P4 being inequivalent (Figure 3). This observation is in
accordance with the solid-state structure of 6, where all
coordinated phosphorus atoms occupy stereochemically differ-
ent positions (see Figure 2 and the inset in Figure 3). The silver
congener 7 displays a similar behavior, with the scrambling rate
being considerably higher in comparison with the dynamics
observed in 6. The 31P room-temperature spectrum (Figure S7
in the Supporting Information) displays a pattern which
corresponds to the high-temperature limit of the PPh2 group
movement about the skeleton to give two signals of 1:3 relative
intensity that fit an idealized symmetry of the tetraphosphine
coordinated to the {Ag2(C2Ph)} moiety. The high-field quartet
(δ −29.1 ppm, 3JPP = 144 Hz) is due to the central phosphorus
atom coupled to three equivalent lateral PPh2 groups, whereas
the low-field multiplet (δ −1.3 ppm, broadened dt) with poorly
resolved couplings to P(2) and two silver nuclei corresponds to
the scrambled diphenylphosphino groups (3JPP = 144 Hz and
The binding fashion of the P4 tetraphosphine in 6−12
somewhat resembles that in trinuclear clusters 2−4. While the
−PPh2 moieties are located at normal distances from the metal
ions, the central P(2) atoms show clearly larger P−M
separations, which exceed 2.7 Å for P(2)−Ag contacts in 11
and 12 and thus become weakly bonding.
The silver cluster 7 differs from other congeners of this
series. In the solid state it possesses a tetranuclear Z-shaped flat
Ag4 skeleton as a result of dimerization of two [(P4)-
Ag2(C2Ph)]+ cations via the formation of supplementary Ag−
Ag and Ag−CC bonds. Because of this fusion the alkynyl
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Figure 3. 31P−31P COSY NMR spectrum of complex 6 (199 K, 162
MHz, CD2Cl2). The inset shows the assignment scheme and spin−
spin coupling network. The top 1D projection (brown) shows a
3
simulated spectrum (2J(P(3)−P(4)) = 57 Hz, J(P(3/4)−P(2)) = 82
3
Hz, J(P(1)−P(2)) = 113 Hz).
1
dynamically averaged JAgP = ca. 200 Hz). In contrast to the
case for 6, fast motion of the ligands could not be completely
frozen even at 193 K and produced three broadened doublets
1
(δ 0.6, −2.4, and −7.7 ppm, JPAg in the range 300−500 Hz)
assigned to diphenylphosphino fragments, along with a high-
field distorted quartet (δ −31.4 ppm, 3JPP = ca. 150 Hz) arising
from the central P(2) nucleus (Figure S7). Independently of
the temperature, the resonance of the P(2) atom in 7 exhibits
nearly no characteristic P−Ag magnetic coupling, evidencing an
extremely weak interaction between this phosphorus atom and
the silver ion or even indicating breakage of the corresponding
bond in solution. Crystallographic data obtained (vide supra)
also point to a poor P(2)−Ag bonding, in accord with which
the P(2)−M bond lengths in complexes 6−12 are systemati-
cally longer than the related distances PPh2−M.
The gold−copper compounds 8−10 adopt essentially the
same structural arrangement (Figure S4 in the Supporting
Information) and exhibit nearly identical 31P{1H} NMR spectra
(see the Experimental Section). In contrast to the case for 6
and 7, these heterometallic species retain their rigid structures
in solution at room temperature, which is indicated by the
presence of four well-resolved multiplets (Figure S8 in the
Supporting Information). Analysis of the JPP = values and
comparison of the chemical shifts with those of other Au−Cu
phosphine complexes described earlier14b,25 allows for an easy
assignment of the low-field doublets (35.2−35.7 ppm) to Au-
coordinated PPh2 groups, while three higher field resonances (δ
8.7 to −6.8 ppm) in each of the spectra correspond to Cu-
bound phosphorus atoms.
Figure 4. (A) 31P−31P COSY NMR spectrum of complex 12 (193 K,
162 MHz, CD2Cl2). The inset shows the assignment scheme and
spin−spin coupling network. The top 1D projection (green) shows a
simulated spectrum (2J(P(3)−P(4)) = 75 Hz, 3J(P(3/4)−P(2)) = 148
and 166 Hz, 3J(P(1)−P(2)) = 68 Hz). (B) VT 31P{1H} NMR spectra
of complex 12 (162 MHz, CD2Cl2).
suggest that both compounds exist in one low-symmetry form,
which corresponds to the motif found in the solid state (Figure
2 and Figure S4 in the Supporting Information). The
spectroscopic patterns for 11 and 12 feature AQQ′X spin
systems, additionally complicated by 107/109Ag−31P couplings of
two lateral phosphorus atoms (Figure 4 and Figure S9).
Analogously to the assignment in 8−10, a low-field doublet
for 11 and 12 (δ 31.6 and 31.8 ppm) is ascribed to the P(1)
atom bound to the gold ion and coupled to the P(2) nucleus.
Two remaining PPh2 groups (δ 1.1−1.3 and 5.5 ppm) are
evidently bound to the Ag(I) center, as the corresponding
multiplets from P(3) and P(4) atoms demonstrate typical
coupling constants JAgP for the 107/109Ag-containing iso-
topomers. The high-field resonance (P(2), δ −7.7 and −9.8
ppm for 11 and 12, respectively) displays only the
phosphorus−phosphorus splitting, pointing to a negligible
P(2)−Ag interaction that is in line with long P(2)−Ag(1)
separations determined in the solid state (see Table S3 in the
Supporting Information).
The solution behavior of Ag−Au complexes 11 and 12
resembles that of 6 and 7, revealing fast intramolecular
dynamics at room temperature on the NMR time scale (Figure
4 and Figure S9 in the Supporting Information). At the low-
temperature limit (193 K) the 31P NMR spectra of 11 and 12
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Heterotrimetallic Cationic Complexes. In order to
extend the synthetic strategy, we employed a related
triphosphine, bis(2-diphenylphosphinophenyl)-
phenylphosphine (P3),20 in an attempt to prepare trinuclear
complexescongeners of the bimetallic compounds 6−12
(Scheme 3). The hypothesized approach involved reacting the
a
Scheme 3. Synthesis of Complexes 13−15
a
Conditions: CH2Cl2/acetone, 3 h, 298 K.
P3 ligand with [Cu(NCMe)4]+ or Ag+ triflates to produce the
coordinatively unsaturated species [M(P3)]+, followed by a
reaction with the anionic dialkynyl complexes [Au-
(C2R)2]−PPN+. The latter were generated in situ according
to the “acac method” developed by Vicente.26 However, no
target complexes, depicted in Scheme 3 (top), could be
isolated. Instead, for the gold−silver mixture a very small
amount of the trinuclear complex [{(P3O)Ag}2Au(C2C(OH)-
Ph2)2]CF3SO3 containing partially oxidized phosphine (P3O =
bis(2-(diphenylphosphino)phenyl)phenylphosphine oxide) was
obtained upon recrystallization. Following the same protocol
with the P3O ligand27 allowed for the preparation of the
[{(P3O)M}2Au(C2R)2]CF3SO3 compounds 13−15 in consid-
erably improved yields (Scheme 3, bottom).
Crystallographic studies revealed that these compounds
possess a gold(I) dialkynyl anion decorated with two cationic
[M(P3O)]+ (M = Cu, Ag) units, which are held together by
means of gold−metal and π-CC−metal bonding (Figure 5
and Figure S10 in the Supporting Information). The metal ions
in 13−15 form an ideal linear arrangement, as well as the
central [Au(C2R)2]− rod (the M−Au−M and C(1)−Au−C(1′)
angles are 180.0°). The intermetallic and metal−ligand
distances are in the normal range determined for the congener
coinage-metal complexes4c,12b,c,g,13e,23 and are comparable to
the corresponding parameters found for compounds 6−12
(Table S4 in the Supporting Information). The relatively long
PO···M contacts in 13−15 are close to those observed in the
mononuclear halide species M(P3O)Hal (M = Cu, Ag),27
pointing to rather loose O−M interactions. It should be noted
that clusters 13 and 14 with hydroxyl-alkynyl ligands are
Figure 5. Molecular views of complexes 13 and 15. Thermal ellipsoids
are shown at the 50% probability level. Counterions and H atoms
(except the O−H atoms) are omitted for clarity. Symmetry
transformations used to generate equivalent atoms (′): in 13, −x,
−y, − z; in 15, 1 − x, −y, 1 − z.
furthermore stabilized by effective −O−H···OP hydrogen
bonding between the alkynyl and phosphine oxide moieties,
which is indicated by short O(1)···O(2) separations (2.806 and
2.787 Å for 13 and 14, respectively).
An ESI-MS investigation of 13−15 shows the presence of
molecular ions with m/z 2029.36 (13), 2117.36 (14), and
1905.26 (15) (Figure S11 in the Supporting Information).
However, in the case of 15 a significant fragmentation can be
observed which presumably results from a lower stability of this
complex in comparison with that of 13 and 14 due to the
absence of efficient intramolecular hydrogen bonding.
The NMR data obtained at room temperature confirm that
the structures of 13−15 found in the solid state are retained.
Their 31P spectra exhibit a pattern which consists of two signals
with a 1:2 ratio of relative intensities. The low-field resonance
(δ 42.3, 38.5, and 37.6 ppm for 13−15, respectively)
corresponds to the phosphine oxide function, while a high-
field multiplet of double intensity (δ −12.5, −2.4 and −2.2
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Table 1. Solid-State Photophysical Properties of 1−15
298 K
77 K
a
b
c
d
λex, nm
415
λem, nm
Φ
τav, μs
kr, s−1
knr, s−1
λex, nm
λem, nm
1
635
583
0.03
0.05
0.08
0.1
1.1
1.3
3.7
1.2
1.7
8.3
1.5
5.5
3.3
2.8
0.6
11.4
2.5
1.7
5.2
2.5 × 104
3.5 × 104
2.2 × 104
8.4 × 104
9.8 × 104
4.4 × 104
8.1 × 104
2.9 × 104
6.2 × 104
9.2 × 104
7.9 × 104
2.7 × 104
1.2 × 105
∼5.0 × 103
8.8 × 104
9.0 × 105
7.1 × 105
2.5 × 105
7.3 × 105
4.7 × 105
7.7 × 104
5.7 × 105
1.5 × 105
2.4 × 105
2.6 × 105
1.7 × 105
6.1 × 104
2.8 × 105
∼5.8 × 105
1.0 × 105
331
325
325
340
633
490, 535, 588
2
329
3
298, 374
325, 365
325, 376
305, 373
327, 382
340, 370
340, 366
337, 371
335, 385
330, 375
372
533
431, 453, 463, 474, 500
4
510
515
5
555
0.17
0.36
0.13
0.16
0.21
0.26
0.04
0.31
0.30
∼0.01
0.46
310, 370
294, 370
330, 385
366
542
6
480
475
7
480
511
8
520
547
9
495
344
490
10
11
12
13
14
15
485
321, 385
335
485
465
477
450
330
451
532
365
523
330 sh, 365
354, 400, 428
485
325
488
440, 481
332, 400, 415, 432
437, 458, 469, 482
a
b
The uncertainty of the quantum yield measurement is in the range of 5% (an average of three replica). Average emission lifetime for all of the
c
complexes except 13 for the two-exponential decay determined by the equation τav = (A1τ12 + A2τ2 )/(A1τ1 + A2τ2); Ai = weight of the i exponent. kr
values were estimated by Φ/τobs
2
d
.
knr values were estimated by kr(1 − Φ)/τobs
.
ppm) is generated by the equivalent metal-bound PPh2 groups
with typical 107/109Ag−31P splitting observed for silver-
containing compounds 14 and 15.
The OH resonances in the 1H NMR spectra of 13 and 14 are
found at δ 6.22 and 6.40 ppm and therefore show a large low-
field shift with respect to those of complexes 10 and 12 having
the same −CCC(OH)Ph2 alkyne, for which the OH signals
were found at δ 2.40 and 2.84 ppm. This dramatic difference
supports the presence of a strong O−H···O attraction in 13 and
14 in solution. The aromatic region of the proton spectra is
compatible as well with the solid-state structures of 13−15,
though the signals are visibly broadened for 15 evidently
because of a lower rigidity of its framework.
Solid-State Photophysical Properties. The title com-
plexes exhibit room-temperature luminescence in the solid state
but virtually are not emissive in solution under ambient
conditions. The fluxional behavior of complexes 1−12 may
introduce effective nonradiative deactivation of the excited
states, resulting in severe quenching of luminescence in the
fluid medium. The trinuclear clusters 13−15 possess intrinsi-
cally flexible frameworks based on the P3O ligand, which was
recently shown to induce emission-free relaxation.27 The
photophysical data are summarized in Table 1; the correspond-
ing spectra are presented in Figures 6−8 (298 K) and Figures
S12−S14 in the Supporting Information (77 K). The excited-
state lifetimes for all of the compounds lie in the range from 0.6
to 11.4 μs, which implies a triplet parentage of photoemission;
this assignment is also supported by significant Stokes shifts
exceeding 100 nm.
Figure 6. Normalized solid-state excitation (dotted lines) and
emission (solid lines) spectra of 1−6 at 298 K.
The mononuclear complex 1 displays a broad emission band
of low intensity (Φ = 0.03) in the orange-red region (λ 635
nm), which is comparable to the characteristics of the
triphosphine-based alkynyl Cu(P3)C2Ph congener (Φ = 0.06,
λ 602 nm).20
The tricopper compound 2 produces a somewhat stronger
luminescence (Φ = 0.05), which is blue-shifted in relation to 1
(λ 583 nm). A comparison to other copper alkynyl clusters12a
allows for a tentative assignment of the emission to Cu3-
centered electronic transitions mixed with MLCT d(Cu) →
π*(CCPh) character. Cooling these samples to 77 K leads to
Figure 7. Normalized solid-state excitation (dotted lines) and
emission (solid lines) spectra of 7−12 at 298 K.
G
DOI: 10.1021/acs.organomet.6b00701
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
LUMO gap in the Au−Cu species and thus red-shifted
emission, which has been noticed earlier for other Au−Cu/
Ag heterometallic assemblies.30 The electronic characteristics of
the −CCR groups affect the optical properties of the title
materials as well. The alkynyl ligands functionalized with
hydroxyl groups tend to cause a hypsochromic shift of
emission, which ultimately gives a deep blue color for 12 (λ
450 nm) at a decent quantum efficiency (Φ = 0.31). This effect
can be presumably attributed to the difference in electronic
properties of aromatic and hydroxyaliphatic alkynyls, as well as
weak noncovalent interactions in the solid state, facilitated by
the presence of polar OH groups. The trinuclear species 13 and
15 are intensely luminescent with quantum yields of 0.30 and
0.46, respectively. Similarly to the dinuclear compounds, the
Au−Cu cluster 13 shows a lower emission energy (λ 532 nm,
Figure 8). The Au−Ag complex 15 displays the highest energy
emission within the entire series 1−15 (λ 440 nm), indicative
of a low-lying ground-state level. The poorly resolved vibronic
structure of the emission band of 15 at 298 K, which is
significantly enhanced at 77 K (Figure S14 in the Supporting
Information), proves a substantial contribution of the intra-
ligand transitions to the emissive excited states.
Figure 8. Normalized solid-state excitation (dotted lines) and
emission (solid lines) spectra of 13−15 at 298 K.
a visible increase in emission energy for 2 and the appearance of
a vibronic structure, the progression of which (ν ca. 1730 cm−1)
indicates substantial contribution of the CCPh fragments
into the frontier orbitals.
CONCLUSIONS
■
The trisilver complexes 3−5 expectedly display a substantial
blue shift of emission bands in comparison to the isostructural
copper analogue 2 in both room- and low-temperature
experiments. The emission profiles of silver alkynyl halide
clusters 3−5 (Figure 6) under ambient conditions constitute
featureless bands, the intensity of which follows the order I
(0.17, 5) > Br (0.1, 4) > Cl (0.08, 3). At 77 K fine vibrational
structure can be seen for the chloride derivative 3, the
maximum of the emission band being blue-shifted from 533 to
431 nm. In contrast, the temperature influence on the
spectroscopic patterns of 4 and 5 is quite minor. Alterations
of emission energies within the series 3−5 may be associated
with a contribution of halide ligands to the excited states, which
originate from a mixture of XLCT/XMCT and MLCT
transitions.28 This assumption is supported by the clearly
visible effect of halides on emission energies at 77 K: λmax (Cl)
< λmax (Br) < λmax (I). However, at room temperature there is
no obvious dependence of λmax as a function of Hal, which is
generally in line with other reports on silver phosphine-halide
luminophores.27,28
The homometallic alkynyl-phosphine copper and silver
complexes 6 and 7, which are shown separately in Figures 6
and 7 to avoid congestion, display closely analogous excitation
and identical emission spectra at 298 K (λ 480 nm) with
moderately good quantum yields (Φ = 0.36 and 0.13) and
relatively long lifetimes (τ = 8.3 and 1.5 μs).
At 77 K the dicopper complex 6 shows a typical small blue
shift of excitation and emission bands, whereas the silver
complex 7, which exists in a tetranuclear form in the solid state,
exhibits a considerable red shift of the emission maximum (λ
511 nm) conceivably due to a contraction of the metal−metal
distances in the cluster core.29 The luminescence of structurally
similar Au−M bimetallic species 8−12 is clearly dependent on
the nature of the heterometal M (Figure 7).
We investigated the preparation of a series of low-nuclearity
alkynyl clusters of d10 coinage metals, stabilized by the
tetradentate chelating phosphine P4 ligand. Application of the
polymeric phenylacetylides of copper and silver as starting
materials affords neutral mononuclear (P4)MC2Ph (1, M = Cu)
or trinuclear (P4)M3(C2Ph)3−xHalx (2−5) complexes. The
combination of (M′C2R)n (M′ = Cu, Ag, Au) acetylides with
M+ (M = Cu, Ag) ions results in the assembly of a range of
dinuclear cationic compounds [(P4)MM′(C2R)]+ (6−12).
Crystallographic analysis of these species indicates that in the
di- and trinuclear clusters the tetraphosphine coordinates
predominantly in a tridentate mode, where the central
phosphorus donor is poorly involved in binding to the metal
centers. Complexes 1−12 were found to be stereochemically
nonrigid in solution and were characterized by variable-
temperature NMR spectroscopic measurements to confirm
that their structures were retained in the fluid medium.
Attempts to synthesize heterotrimetallic compounds employing
a congener phosphine of a lower denticity, P3, and dialkynyl
anionic precursors [Au(C2R)2]− led to the formation of target
metal frameworks only via partial oxidation of the triphosphine,
giving the clusters [{(P3O)M}2Au(C2R)2]+ (13−15). Com-
plexes 1−15 are virtually nonluminescent in solution, and their
photoemissive properties were studied in the solid state at 298
and 77 K to reveal weak to moderately intense phosphor-
escence (Φem up to 0.46), which covers the range from 440 to
635 nm under ambient conditions. The optical behavior of the
title compounds expectedly depends on both the composition
and structure of the metal core and the characteristics of the
ligand environment. In particular, the copper-containing
complexes display a systematic red shift of the emission
maxima in comparison to the silver congeners, while the
electronic properties of the alkynyl −CCR groups, utilized in
this study, have a less pronounced effect, which is reflected by a
hypsochromic shift upon changing the R substituent from
aromatic to hydroxyaliphatic. For most of the compounds the
radiative excited states are tentatively assigned to cluster-
centered transitions mixed with some MLCT d → π*(alkyne)
character, while the spectroscopic profile of complex 15
The gold−copper compounds 8−10 display systematically
lower emission energies with respect to their silver counterparts
11 and 12 that can be explained by stabilization of the ground-
state HOMO levels in the case of Ag-containing complexes.
This effect of copper vs silver leads to a reduced HOMO−
H
DOI: 10.1021/acs.organomet.6b00701
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
indicates that the 3IL transitions are substantially engaged in the
observed luminescence.
4 at 278 K to give a colorless crystalline material (87 mg, 84%).
31P{1H} NMR (CD2Cl2, 298 K, δ): −6.6 (d, 3JPP = 161 Hz, 3P, PPh2),
−33.9 (br, 1P, P(C6H4PPh2)3). 1H NMR (CD2Cl2, 298 K, δ): 7.48 (m
br, 14H), 7.39 (m br, 9H), 7.25−7.16 (m, 6H), 7.15−7.03 (m, 12H),
EXPERIMENTAL SECTION
3
■
6.80 (t br, JHH = ca. 7.0 Hz, 3H), 6.49 (br, 3H). Anal. Calcd for
General Information. (2-Bromophenyl)diphenylphosphine,31 bis-
(2-(diphenylphosphino)phenyl)phenylphosphine oxide (P3O),27 and
the complexes (CuC2Ph)n,32 (AgC2Ph)n,33 AuC2R (R = Ph, −C(OH)
(CH3)2, −C(OH)Ph2),34 and [Au(acac)2]PPN (acac = acetylaceto-
nate)35 were synthesized according to the published procedures.
Tetrahydrofuran (THF) was distilled over Na-benzophenone ketyl
under a nitrogen atmosphere prior to use. Other reagents and solvents
C62H47Br2P4Ag3: C, 53.22; H, 3.39. Found: C, 53.10; H, 3.21.
(P4)Ag3(C2Ph)I2 (5). Recrystallized by gas-phase diffusion of diethyl
ether into an acetone/dichloromethane (2/1 v/v mixture) solution at
278 K to give a colorless crystalline material (74 mg, 67%). 31P{1H}
3
NMR (CD2Cl2, 298 K, δ): −6.8 (d, JPP = 153 Hz, 3P, PPh2), −32.4
(br, 1P, P(C6H4PPh2)3). 1H NMR (CD2Cl2, 298 K, δ): 7.35−7.55 (m,
23H), 7.25−7.05 (m, 18H), 6.77 (m br, 3H), 6.41 (m br, 3H). Anal.
Calcd for C62H47I2P4Ag3: C, 49.87; H, 3.17. Found: C, 50.03; H, 3.14.
[(P4)Cu2(C2Ph)]PF6 (6). Freshly prepared (CuC2Ph)n (12.3 mg,
0.074 mmol) was suspended in acetone (5 cm3), and a solution of P4
(60.0 mg, 0.074 mmol) in dichloromethane (5 cm3) was added. The
reaction mixture was stirred for 30 min in the absence of light, and a
solution of Cu(NCMe)4PF6 (27.6 mg, 0.074 mmol) in acetone (5
cm3) was added. The resulting light greenish reaction mixture was
stirred for 30 min and evaporated, and the residue was recrystallized by
gas-phase diffusion of pentane into a dichloromethane solution of 6 at
278 K to give yellow greenish crystalline material (49 mg, 56%). ESI-
MS (m/z): [M]+ 1041.14 (calcd 1041.12). 31P{1H} NMR (CD2Cl2,
1
1
were used as received. The solution H, 31P{1H}, and H−1H COSY
NMR spectra were recorded on a Bruker Avance 400 spectrometer.
Mass spectra were determined on a Bruker micrOTOF 10223
instrument in the ESI+ mode. Microanalyses were carried out in the
analytical laboratory of the University of Eastern Finland.
Tris(2-diphenylphosphino)phenylphosphine (P4). The ligand
was obtained via a modified protocol.36 The synthesis was carried out
under a nitrogen atmosphere. A solution of 2-(bromophenyl)-
diphenylphosphine (1.5 g, 4.4 mmol) in THF (20 mL) was cooled
to −78 °C, and a 1.6 M solution of n-BuLi (3.0 mL, 4.8 mmol) was
added within 10 min to give a light yellow solution. It was stirred for 1
h at −78 °C and then treated dropwise with neat PCl3 (0.20 g, 1.45
mmol). The pale reaction mixture was stirred below −70 °C for 2 h
and overnight at room temperature, quenched with methanol (2 mL),
and evaporated. The yellow residue was washed with methanol (3 ×
15 mL), dried, dissolved in dichloromethane, and passed through a
pad of silica gel (150 mesh, 2 × 5 cm). The resulting solution was
diluted with ethanol and slowly evaporated at +5 °C to afford a
colorless crystalline material (0.73 g, 61%). The spectroscopic data are
identical with those reported earlier.37 31P{1H} NMR (CDCl3, 298 K,
δ): AB3 spin system −22.5 (3JPP = 145 Hz, 1P), −14.1 (3JPP = 145 Hz,
3P). 1H NMR (CDCl3, 298 K, δ): 7.72 (m, 1H), 7.19 (m, 13H), 7.07
(m, 10H), 6.8 (m, 2H).
199 K, δ): 5.4 (dd, 2JPP = 57 and 3JPP = 82 Hz, 1P, PPh2), 3.6 (d, 3JPP
=
2
3
113 Hz, 1P, PPh2), −2.4 (dd, JPP = 57 and JPP = 82 Hz, 1P, PPh2),
−6.9 (dt, 3JPP = 82 and 113 Hz, 1P, P(C6H4PPh2)3), −144.6 (sept, 1P,
PF6). 1H NMR (CD2Cl2, 199 K, δ): 7.70 (dd, 3JHP 10.9 Hz, 3JHH = 7.7
Hz, 2H), 7.58−7.39 (m, 14H), 7.39−7.25 (m, 4H), 7.24−7.01 (m, 20
H), 6.98 (t, 3JHH = 7.1 Hz, 2H), 6.78 (m, 1H), 6.62 (dd, 3JHP 10.6 Hz,
3JHH = 7.8 Hz, 2H), 6.45 (m, 1H), 6.19 (m, 1H). Anal. Calcd for
C62H47F6P5Cu2: C, 62.68; H, 3.99. Found: C, 62.41; H, 4.11.
[(P4)2Ag4(C2Ph)2](PF6)2 (7). A solution of AgPF6 (18.7 mg; 0.074
mmol) in acetone (5 cm3) was added to a mixture of AgC2Ph (15.4
mg; 0.074 mmol) and P4 (60.0 mg, 0.074 mmol) in dichloromethane
(5 cm3). The resulting solution was stirred for 2 h in the absence of
light and then evaporated, and the residue was recrystallized by gas-
phase diffusion of pentane into an acetone solution of 7 at 278 K to
give a colorless crystalline material (66 mg, 70%). ESI-MS (m/z):
[0.5M]+ 1129.08 (calcd 1129.07). 31P{1H} NMR (acetone-d6, 298 K,
δ): −1.3 (br, dt, 3JPP = 144 Hz, av. 1JPAg ca. 200 Hz, 3P, PPh2), −29.1
(P4)CuC2Ph (1). A mixture of (CuC2Ph)n (12.2 mg, 0.074 mmol)
and P4 (60 mg, 0.074 mmol) in dichloromethane (10 cm3) was stirred
for 2 h in the absence of light. The resulting bright yellow solution was
filtered through Celite and evaporated. The solid residue was
recrystallized by gas-phase diffusion of diethyl ether into a dichloro-
methane solution of 1 at 278 K to afford yellow crystalline material (66
mg, 92%). 31P{1H} NMR (CD2Cl2,193 K, δ): −24.5 (m, 1P,
noncoordinated PPh2), 0.4 (m, 1P, P(C6H4PPh2)3, 6.2 (m, 2P,
PPh2). 1H NMR (CD2Cl2, 298 K, δ): 7.59 (br m, 5H), 7.42 (dm, 3JHH
= 7.1 Hz, 2H), 7.08−7.39 (m, 37H), 7.04 (t, 3JHH = 7.5 Hz, 3H). Anal.
Calcd for C62H47P4Cu: C, 76.03; H, 4.84. Found: C, 75.85; H, 4.89.
(P4)Cu3(C2Ph)3 (2). This complex was prepared similarly to 1 from
(CuC2Ph)n (37.0 mg, 0.224 mmol) and P4 (60 mg, 0.074 mmol).
Yellow crystalline material (51 mg, 53%). 31P{1H} NMR (CD2Cl2, 298
K, δ): −10.8 (d br, 3JPP = ca. 73 Hz, 3P, PPh2), −14.6 (q br, 3JPP = ca.
3
(q, JPP = 144 Hz, 1P, P(C6H4PPh2)3), −144.8 (sept, 1P, PF6).
3
31P{1H} NMR (acetone-d6, 193 K, δ): 0.6 (dd br, JPP = ca. 148 Hz,
1
1JPAg ca. 510 Hz, 1P, PPh2), −2.4 (d br, JPAg ca. 300 Hz, 1P, PPh2),
1
3
−7.7 (d br, JPAg ca. 390 Hz, 1P, PPh2), −31.4 (q, JPP = 148 Hz, 1P,
P(C6H4PPh2)3), −144.8 (sept, 1P, PF6). 1H NMR (acetone-d6, 298 K,
δ): 7.60 (m, 9H), 7.47 (m, 6H), 7.43−7.28 (m, 14H), 7.27−7.20 (m,
9H), 7.15−7.08 (m, 6H), 6.81 (m, 3H). Anal. Calcd for
C62H47F6P5Ag2: C, 58.33; H, 3.71. Found: C, 57.96; H, 3.83.
[(P4)AuM(C2R)]PF6 Complexes (M = Cu, Ag; R = Ph,
−C(OH)(CH3)2, −C(OH)Ph2). Au(C2R) (0.074 mmol) was suspended
(dissolved for R = −C(OH)Ph2) in dichloromethane (5 cm3), and P4
(60.0 mg, 0.074 mmol) was added, followed by a solution of AgPF6 or
Cu(NCMe)4PF6 (0.074 mmol) in acetone (5 cm3). The reaction
mixture was stirred for 2 h in the absence of light. The resulting
transparent solution was evaporated, and the crude solid was
recrystallized by a gas-phase diffusion of diethyl ether into a
dichloromethane (5, 7−9) or acetone (6) solution of the
corresponding complex at 278 K.
1
73 Hz, 1P P(C6H4PPh2)3). H NMR (CD2Cl2, 298 K, δ): 7.83 (br,
6H), 7.60 (t, 3JHH = 7.9 Hz, 6H), 7.37−7.24 (m, 12H), 7.21 (t, 3JHH
=
3
7.4 Hz, 3H), 7.19−7−12 (m, 15H), 7.08 (t, JHH = 7.4 Hz, 6H), 7.03
3
(t, JHH = 7.9 Hz, 3H), 6.35 (br, 3H), 5.63 (br, 3H). Anal. Calcd for
C76H57P4Cu3: C, 71.58; H, 4.39. Found: C, 71.39; H, 4.48.
(P4)Ag3(C2Ph)X2 (X = Cl, Br, I). A mixture of P4 (60.0 mg, 0.074
mmol), AgC2Ph (30.8 mg; 0.074 mmol), and AgX (0.147 mmol) in
dichloromethane (15 cm3) was stirred for 5 h in the absence of light.
The solution was filtered through Celite and evaporated, and the solid
residue was purified by recrystallization.
[(P4)AuCu(C2Ph)]PF6 (8). Yellow crystalline material (66 mg, 68%).
(P4)Ag3(C2Ph)Cl2 (3). Recrystallized by gas-phase diffusion of diethyl
ether into a dichloromethane solution of 3 at 278 K to give a colorless
crystalline material (73 mg, 75%). 31P{1H} NMR (CD2Cl2, 298 K, δ):
−5.4 (d, 3JPP = 155 Hz, 3P, PPh2), −33.0 (br, 1P, P(C6H4PPh2)3). 1H
NMR (CD2Cl2, 298 K, δ): 7.50 (m br, 14H), 7.35 (m br, 9H), 7.22−
7.06 (m, 15H), 7.03 (m br, 3H), 6.86 (t, 3JHH = 7.5 Hz, 3H), 6.60 (m
br, 3H). Anal. Calcd for C62H47Cl2P4Ag3: C, 56.83; H, 3.62. Found: C,
56.59; H, 3.77.
ESI-MS (m/z): [M]+ 1175.18 (calcd 1175.16). 31P{1H} NMR
3
(CD2Cl2, 298 K, δ): 35.5 (d, JPP = 48 Hz, 1P, Au-PPh2), 7.6 (ddd,
3JPP = 138, 125, 48 Hz, 1P, P(C6H4PPh2)3), 1.6 (dd br, 3JPP = 138 and
2JPP = 54 Hz, 1P, PPh2), −5.8 (dd br, 3JPP = 125 and 2JPP = 54 Hz, 1P,
PPh2), −144.6 (sept, 1P, PF6). 1H NMR (CD2Cl2, 298 K, δ): 7.67 (m,
2H), 7.61−7.18 (m, 28H), 7.15−7.09 (m, 5H), 7.09−6.97 (m, 7H),
3
3
6.93 (dd, JHP 11.7 Hz, JHH = 6.5 Hz, 1H), 6.62 (m, 3H), 6.37 (dd,
3JHP 11.0 Hz, 3JHH = 6.7 Hz, 1H). Anal. Calcd for C62H47F6P5AuCu: C,
56.35; H, 3.59. Found: C, 56.44; H, 3.70.
(P4)Ag3(C2Ph)Br2 (4). Recrystallized by gas-phase diffusion of diethyl
ether into an acetone/dichloromethane (1/1 v/v mixture) solution of
I
DOI: 10.1021/acs.organomet.6b00701
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Article
[(P4)AuCu(C2C(OH) (CH3)2)]PF6 (9). Yellow crystalline material (80
mg, 83%). ESI-MS (m/z): [M]+ 1157.19 (calcd 1157.17). 31P{1H}
NMR (CDCl3, 298 K, δ): 7.64 (d, 3JHH = 6.9 Hz, 8H), 7.53 (t, 3JHH
=
7.3, 2H), 7.35 (m, 12H), 7.28−7.04 (m, 48H), 7.00 (dt, 3JHH = 7.5 Hz,
3
3
NMR (CD2Cl2, 298 K, δ): 35.7 (d, JPP = 47 Hz, 1P, Au-PPh2), 8.7
4H), 6.88 (m, 4H), 6.79 (dd, JHH = 7.5, 7.1 Hz, 8H), 6.40 (s, OH,
(ddd, 3JPP = 135, 127, 47 Hz, 1P, PPh2), 1.4 (dd br, 3JPP = 135 and 2JPP
1H). Anal. Calcd for C115H88F3O7P6SAuAg2: C, 60.86; H, 3.91.
Found: C, 60.84; H, 3.96.
= 65 Hz, 1P, PPh2), −6.7 (dd, 3JPP = 127 and 2JPP = 65 Hz, 1P, PPh2),
1
[(P3O)2AuAg2(C2Ph)2]CF3SO3 (15). Recrystallization by gas-phase
diffusion of diethyl ether into a dichloromethane/methanol (1/1 v/v
mixture) solution of 15 at 278 K gave colorless crystalline material (63
−144.6 (sept, 1P, PF6). H NMR (CD2Cl2, 298 K, δ): 7.65 (m, 2H),
7.60−7.42 (m, 13H), 7.37 (m, 4H), 7.32−7.16 (m, 12H), 7.15−7.02
(m, 6H), 6.93 (dd, 3JHP 11.6 Hz, 3JHH = 6.7 Hz, 1H), 6.82 (dd, 3JHH
=
3
8.2, 8.6 Hz,, 2H), 6.59 (t, JHH = 6.6 Hz, 1H), 6.37 (dd, 3JHP 10.1 Hz,
3JHH = 6.6 Hz, 1H), 1.47 (s br, OH, 1H), 1.33 (s, CH3, 3H), 1.30 (s,
CH3, 3H). Anal. Calcd for C59H49OF6P5AuCu: C, 54.37; H, 3.79.
Found: C, 54.46; H, 4.42.
mg, 61%). ESI-MS (m/z): [M]+ 1905.26 (calcd 1905.20). 31P{1H}
1
109AgP
NMR (CD2Cl2, 298 K, δ): 37.6 (s, 2P, P(O)Ph), −2.2 (d, J
=
1
1
107AgP
400 Hz, J
= 349 Hz, 4P, PPh2). H NMR (CD2Cl2, 298 K, δ):
7.63−7.36 (m, 20H), 7.34−7.12 (m, 40H), 7.01 (m, 12H), 6.93 (br,
4H). Anal. Calcd for C101H76F3O5P6SAuAg2: C, 58.97; H, 3.72.
Found: C, 58.96; H, 3.76.
[(P4)AuCu(C2C(OH)Ph2)]PF6 (10). Yellow crystalline material (75
mg, 71%). ESI-MS (m/z): [M]+ 1281.22 (calcd 1281.20). 31P{1H}
NMR (CD2Cl2, 298 K, δ): 35.2 (d, 3JPP = 49 Hz, 1P, PPh2), 7.0 (ddd,
X-ray Structure Determination. The crystals of 1−4 and 6−15
were immersed in cryo-oil, mounted in a Nylon loop, and measured at
a temperature of 120 or 150 K. The X-ray diffraction data were
collected on Bruker SMART APEX II, Bruker Kappa Apex II, and
Bruker Kappa Apex II Duo diffractometers using Mo Kα radiation (λ =
0.71073 Å). The APEX2 (2009 #15764) program package was used
for cell refinements and data reductions. The structures were solved by
direct methods using the SHELXS-201338 programs with the
WinGX39 graphical user interface. A semiempirical absorption
correction (SADABS)40 was applied to all data. Structural refinements
were carried out using SHELXL-2014.38
3
3JPP = 137, 132, 49 Hz, 1P, P(C6H4PPh2)3), 2.1 (dd, JPP = 137 and
3
2
2JPP = 61 Hz 1P, PPh2), −6.8 (dd, JPP = 132 and JPP = 61 Hz, 1P,
PPh2), −144.6 (sept, 1P, PF6). 1H NMR (CD2Cl2, 298 K, δ): 7.67 (dd,
3JHH = 7.8, 8.5 Hz, 2H), 7.62−7.48 (m, 10H), 7.47−7.32 (m, 8H),
3
7.29 (t, JHH = 7.6 Hz, 1H), 7.25−7.14 (m, 14H), 7.11−6.91 (m,
10H), 6.80 (dd, 3JHP 11.7 Hz, 3JHH = 6.6 Hz, 1H), 6.58 (dd, 3JHH = 7.6,
7.0 Hz, 1H), 6.42−6.32 (m, 3H), 2.40 (s, OH, 1H). Anal. Calcd for
C69H53OF6P5AuCu: C, 58.05; H, 3.74. Found: C, 57.59; H, 3.71.
[(P4)AuAg(C2Ph)]PF6 (11). Yellow crystalline material (73 mg,
73%). ESI-MS (m/z): [M]+ 1219.15 (calcd 1219.13). 31P{1H} NMR
(CD2Cl2, 192 K, δ): AQQ′X spin system 3JAX = 67 Hz, 3JQX = 158 Hz,
−
−
3JQ′X = 139 Hz, 2JQ′Q = 78 Hz; 31.8 (d, 1P, Au−PPh2), 1.1 (m, 1J
Some phenyl rings in 1, 11, and 12 and PF6 and CF3SO3
109AgP
1
1
counterions in 11 and 13−15 were modeled to be disordered between
two sites each. A series of displacement and geometry constraints and
restraints were applied to these moieties. The CC carbon atoms in
1, 3, and 4 were constrained so that their Uij components were
approximately equal, while in 1 and 3 these atoms were also restrained
so that their Uij values approximated isotropic behavior.
The crystallization solvent was lost from the crystals of 2, 4, 7, 8, 12,
14, and 15 and could not be reliably determined. The contribution of
missing solvent to the calculated structure factors was taken into
account by using a SQUEEZE routine of PLATON41 and was not
included in the unit cell content. In addition, some of the partially lost
solvent molecules (CH2Cl2 in 3, 8, and 12, acetone in 4, diethyl ether
in 11) were refined with 0.5 occupancy.
All H atoms in 1−4 and 6−15 were positioned geometrically and
constrained to ride on their parent atoms, with O−H = 0.84 Å, C−H =
0.95−0.99 Å, and Uiso = 1.2−1.5Ueq (parent atom). The crystallo-
graphic details are summarized in Table S1 in the Supporting
Information.
Photophysical Measurements. The steady-state emission and
excitation spectra of complexes 1−15 in the solid state at 298 and 77 K
was carried out on FluoroMax 4 and FluoroLog 3 Horiba
spectrofluorometers. The emission was excited using xenon lamps
(300 and 450 W). Two LEDs (maximum of emission at 340 and 390
nm) were used in pulse mode to pump luminescence for the lifetime
measurements at room temperature (pulse width 1.2 nm, repetition
rate 100 Hz to 10 kHz). The absolute emission quantum yields of
powder samples were determined using a FluoroLog 3 Horiba
spectrofluorometer and a Quanta-phi integration sphere.
107AgP
109AgP
= 422 Hz, J
= 370 Hz, 1P, PPh2), −5.5 (m, J
= 417 Hz,
1J
= 360 Hz, 1P, PPh2), −7.7 (m, 1P, P(C6H4PPh2)3), −144.6
107AgP
1
(sept, 1P, PF6). H NMR (CD2Cl2, 298 K, δ): 7.61−7.50 (m, 9H),
7.40 (m, 9H), 7.45−7.13 (m, 29H), 7.11 (br, 3H), 7.01 (br, 3H), 6.76
(br, 3H). Anal. Calcd for C62H47F6P5AuAg: C, 54.53; H, 3.47. Found:
C, 54.84; H, 3.80.
[AuAg(P4)(C2C(OH)Ph2)]PF6 (12). Colorless crystalline material (85
mg, 78%). ESI-MS (m/z): [M]+ 1325.20 (calcd 1325.18). 31P{1H}
3
3
NMR (CD2Cl2, 192 K, δ): AQQ′X spin system JAX = 68 Hz, JQX
=
166 Hz, 3JQ′X = 148 Hz, 2JQ′Q = 75 Hz; 31.6 (d, 1P, Au−PPh2), 1.3 (m,
1
1
1
109
107
AgP
109
AgP
J
= 430 Hz, J
= 374 Hz, 1P, PPh2), −5.5 (m, J
= 417
AgP
1
107
Hz, J AgP = 360 Hz, 1P, PPh2), −9.8 (m, 1P, P(C6H4PPh2)3), −144.6
(sept, 1P, PF6). H NMR (CD2Cl2, 298 K, δ): 7.60 (m, 6H), 7.54 (t,
1
3JHH = 7.3 Hz, 6H), 7.48 (dd, 3JHH = 8.3, 1.1 Hz, 2H), 7.3−6.9 (m br,
35H), 6.70 (br, 3H), 2.84 (s, OH, 1H). Anal. Calcd for
C69H53OF6P5AuAg: C, 56.31; H, 3.63. Found: C, 56.26; H, 3.94.
[(P3O)2AuM2(C2R)2]CF3SO3 Complexes (M = Cu, Ag; R =
−C(OH)Ph2, Ph). A degassed solution of [Au(acac)2]PPN (47 mg,
0.05 mmol) and HC2R (0.11 mmol) in dichloromethane (5 cm3) was
stirred under a nitrogen atmosphere for 3 h in the absence of light.
Then a separately prepared mixture of Cu(NCMe)4CF3SO3 (38 mg;
0.1 mmol) or AgCF3SO3 (26 mg; 0.1 mmol) and P3O (65 mg, 0.1
mmol) in acetone (5 cm3) was added, and the reaction solution was
stirred for an additional 3 h. The solvents were evaporated, and the
residue was washed with methanol (2 × 2 cm3) and recrystallized.
[(P3O)2AuCu2(C2C(OH)Ph2)2]CF3SO3 (13). Recrystallization by gas-
phase diffusion of diethyl ether into an acetone solution of 13 at 278 K
gave yellow crystalline material (73 mg, 67%). ESI-MS (m/z): [M]+
2029.36 (calcd 2029.34). 31P{1H} NMR (CD2Cl2, 298 K, δ): 42.3 (s,
2P, P(O)Ph), −12.5 (s, 4P, PPh2). 1H NMR (CD2Cl2, 298 K, δ): 7.66
(t, 3JHH = 7.3 Hz, 2H), 7.60 (dm, 3JHH = 8.2 Hz, 8H), 7.50 (ddd, 3JHH
ASSOCIATED CONTENT
4
3
3
■
= 7.8, 7.3, JHP 3.3 Hz, 4H), 7.37 (dd, JHP 11.8 Hz, JHH = 7.8 Hz,
4H), 7.34−7.15 (m, 24H), 7.13 (t, 3JHH = 7.5 Hz, 4H), 7.04 (t, 3JHH
=
S
* Supporting Information
7.5 Hz, 4H), 6.95 (dt, 3JHH = 7.5, 7.6 Hz, 8H), 6.74 (dd, 3JHH = 7.5, 7.2
Hz, 8H), 6.72 (m, 4H), 6.22 (s, OH, 1H). Anal. Calcd for
C115H88F3O7P6SAuCu2: C, 63.33; H, 4.07. Found: C, 63.25; H, 4.15.
[(P3O)2AuAg2(C2C(OH)Ph2)2]CF3SO3 (14). Recrystallization by gas-
phase diffusion of diethyl ether into a dichloromethane/methanol (1/1
v/v mixture) solution of 14 at 278 K gave colorless crystalline material
(63 mg, 56%). ESI-MS (m/z): [M]+ 2117.36 (calcd 2117.29). 31P{1H}
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.6b00701.
Crystal data for 1−4 and 6−15, molecular views of
selected complexes, additional NMR and ESI-MS
spectra, and excitation and emission spectra (PDF)
Crystal data for 1−4 and 6−15 (CIF)
3
NMR (CDCl3, 298 K, δ): 38.5 (t, JPP = 6.6 Hz, 2P, P(O)Ph), −2.4
1
1
3
1
109
AgP
107
(dd, J
= 410 Hz, J
= 356 Hz, JPP = 6.6 Hz, 4P, PPh2). H
AgP
J
DOI: 10.1021/acs.organomet.6b00701
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
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AUTHOR INFORMATION
■
Corresponding Authors
*E-mail for S.P.T.: stunik@inbox.ru.
*E-mail for I.O.K.: igor.koshevoy@uef.fi.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
́
Financial support from the Academy of Finland (grant 268993,
I.O.K., synthesis and XRD study) and the Russian Science
Foundation (grant 16-13-10064, E.V.G., spectroscopic charac-
terization in solution and photophysical measurements) is
gratefully acknowledged. The photophysical and NMR
measurements were performed using core facilities of St.
Petersburg State University Research Park: Centers for
Magnetic Resonance and for Optical and Laser Materials
Research.
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DOI: 10.1021/acs.organomet.6b00701
Organometallics XXXX, XXX, XXX−XXX