Synthesis and solid-state structures of gold(i) complexes of diphosphines

Article abstract of DOI:10.1039/c6nj00786d

A series of functionalized diphosphine bisgold(i) complexes have been prepared from the corresponding diphosphine ligands Ar₄P₂ (Ar = MeC₆H₄, MeOC₆H₄, Me₂NC₆H₄) and characterized by NMR spectroscopy and APCI mass spectrometry. Single-crystal X-ray diffraction analyses were performed to study the presence and importance of unsupported aurophilic interactions for the structure formation of these compounds. In general, the complexes featured monomeric structures with an antiperiplanar arrangement of the two AuCl units. The crystal packing greatly depended on the position of the substitution pattern (ortho vs. para). While for the ortho-substituted systems (OMe and NMe₂) no ordered 3-dimensional networks were observed, the para-functionalized compounds formed regular layer structures. Here, aurophilic Au?Au interactions only played a minor role compared to intermolecular π?π interactions and hydrogen bonds.

Full text of DOI:10.1039/c6nj00786d

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. Molitor, C.
Mahler and V. H. Gessner, New J. Chem., 2016, DOI: 10.1039/C6NJ00786D.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/njc

Please do not adjust margins
New Journal of Chemistry
Page 1 of 9
View Article Online
DOI: 10.1039/C6NJ00786D
New Journal of Chemistry
ARTICLE
Synthesis and Solid-State Structures of Gold(I) Complexes of
Diphosphines
Sebastian Molitor, Christoph Mahler and Viktoria H. Gessner*
Received 00th January 20xx,
Accepted 00th January 20xx
A series of functionalized diphosphine bisgold(I) complexes has been prepared from the
corresponding diphosphine ligands Ar4P2 (Ar = MeC6H4, MeOC6H4, Me2NC6H4) and characterized by
NMR spectroscopy and APCI mass spectrometry. Single-crystal X-ray diffraction analyses were
performed to study the presence and importance of unsupported aurophilic interactions for the
structure formation of these compounds. In general, the complexes featured monomeric structures
with an antiperiplanar arrangement of the two AuCl units. The crystal packing greatly depended on
the position of the substitution pattern (ortho vs. para). While for the ortho-substituted systems
(OMe and NMe2) no ordered 3-dimensional networks were observed, the para-functionalized
compounds formed regular layer structures. Here, aurophilic Au∙∙∙Au interactions only played a
DOI: 10.1039/x0xx00000x
www.rsc.org/
minor role compared to intermolecular ∙∙∙ interactions and hydrogen bonds.
Recently, our group has established a new route to aryl-
substituted diphosphines employing lithium carbenoids for the
dehydrocoupling of secondary phosphines.6 With a number of
functionalized systems in hand we were interested in their
utility as ligands. We particularly set focus on their coordina-
tion ability towards gold(I) species and their molecular
structures. Gold(I) phosphine complexes have found a variety
of applications in the past years. Besides being potent catalysts
in a number of transformations (e.g. cyclisation or hydro-
amination reactions),7 multimetallic gold complexes have also
been studied due to their photophysical properties. Thereby,
photoluminesence is strongly influenced by aurophilic inter-
actions between gold centres.8 Since these interactions are
often most pronounced in the ordered crystalline phase,
photoluminescence has often only been observed in the solid
state.9
Introduction
In a historic perspective, phosphine ligands have crucially
contributed to the development of organometallic chemistry
from an exotic to a well-established field in chemistry which is
nowadays of utmost importance in academia as well as
industry. Particularly, early advances in homogeneous catalysis
are closely connected with the design of phosphines as ligands
in transition metal complexes. Thereby, phosphines are espe-
cially attractive as they allow for a tuning of the electronic and
steric properties in a rather predictable fashion.1 Compared to
phosphines, diphosphines have only scarcely been explored in
coordination chemistry. Although various methods are
available for the preparation of diphosphines, these protocols
generally featured limitations, particularly regarding efficiency
or functional group tolerance.2,3 Thus, studies concerning the
coordination chemistry of diphosphines have greatly been
restricted and many reports on diphosphine complexes based
on the in situ P‒P coupling in phosphorus metal species (e.g.
phosphido or phosphinidene complexes).4 Nevertheless,
diphosphines have been shown to be potent bridging ligands,
which may link two metals in close proximity to each other and
thus can stabilize interesting bimetallic systems. Until today,
these studies have mainly focussed on the “parent”
tetraphenyldiphosphine, Ph2PPPh2, as diphosphine.5
Diphosphine gold complexes have so far only scarcely been
explored in gold chemistry. In theory, the distance of the two
gold centres may vary strongly depending on the torsion angle
of the M‒P‒P‒M linkage (Figure 1a). This has been studies by
Mizuta and co-workers employing phosphacycle
A with a rigid
naphthalene bridge. Depending on the use of the cis- or trans-
isomer anti- or syn-periplanar arrangements of the two Au
moieties could selectively been prepared (Figure 1b).10,11
Interestingly, Au‒Au interactions led to the formation of a
dimeric structure in the solid state of the cis-isomer.
Hence, we wondered, if the torsion angle may be influenced
by the variation of the aryl substituents of the diphosphine and
if also intra- or intermolecular aurophilic interactions may be
present depending on the substitution pattern. Here we
present our results.
a.Institut für Anorganische Chemie, Julius-Maximilians-Universität Wü
, Germany; Email: vgessner@uni-wuerzburg.de
Electronic Supplementary Information (ESI) available: Experimental procedures,
characterization data, crystallographic and computational details. See
DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 2015
New J. Chem., 2015, 01, 1-4 | 1
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 2 of 9
ARTICLE
New Journal of Chemistry
complexes mass spectra could be obtained by this method.
View Article Online
Hence, atmospheric pressure chemical DioOnI:i1z0a.t1i0o3n9/C(A6NPJC0I)07w86aDs
used, which was shown to evoke fewer electrochemical
degradation processes compared to ESI.14 The APCI mass
spectra (positive mode) of all compound showed peaks for the
corresponding molecular ions [M]+ and the [M–Cl]+ or [M+H]+
ions, respectively, arising from a combination of charge- and
proton-transfer ionization processes. In the negative mode,
however, no molecular ion peak could be detected. Instead
the mayor peak corresponded to the mass of half of the
complex, which is formed by P–P bond cleavage, a typical
reactivity of diphosphines.15
Figure 1. (a) Anti- and syn-periplanar conformers of diphosphine bis(gold) complexes;
(b) cis and trans isomer of ligand A by Mizuta.
Results and discussion
Synthesis and Characterization. The diphosphine ligands were
prepared from the corresponding secondary phosphines
according to a procedure previously established in our
laboratories.6 Diphosphines 1a-g were chosen with methyl,
methoxy and dimethylamino substituents in ortho or para-
position of the phenyl moiety to address steric as well as
electronic effects on the complexation behaviour. The
synthesis of the diphosphine bis(gold) complexes 2a-g was
accomplished using the common ligand-exchange protocol
with (tht)AuCl (tht = tetrahydrothiophene) as precursor
(Scheme 1). Stirring of the corresponding diphosphines with
the gold(I) species for 1 h at room temperature resulted in the
clean formation of a new species as was evidenced by 31P{1H}
NMR spectroscopy. The complexes were isolated as colourless
solids in 60 to 96 % yield (see the experimental section for
details) and characterized by multi-nuclear NMR spectroscopy,
mass spectrometry and X-ray diffraction analysis (except for 2f
and 2g; vide infra).12 The 31P{1H} NMR spectra of all complexes
showed the expected down-field shift compared to the free
diphosphine ligands, e.g. from –19.0 ppm in 1a to 29.5 ppm in
2a. The 1H and 13C{1H} NMR spectra exhibited all signals
expected for the aryl substituents (see ESI for NMR spectra).
Single-crystals of the diphosphines
1 and the complexes 2a-2e
were obtained by either cooling or slowly evaporating of
saturated DCM solutions.6 Due to the low solubility of 2f and
2g in all commonly used organic solvent neither NMR
spectroscopic studies were possible, nor suitable crystals for X-
ray diffraction analysis could be obtained. Crystallographic
details for all structure determinations including structural
details for the diphosphines 1d-1f are given in the Supporting
Information. Figure 2 exemplarily depicts the molecular
structures of the para-substituted complex 2b as well as the
ortho-functionalized systems 2d and 2e. Selected bond lengths
and angles of the complexes are given in Table 1. In the crystal,
all gold complexes exhibit monomeric structures, i.e. no
dimerization via Au---Au interactions is observed, as has been
found in case of complexes with the rigid phosphacycles
(Figure 1). Interestingly, the coordination to the Au(I)Cl unit
has no effect on the P–P distance. As such, the P‒P bond in 1a
A
:
[2.239(2) Å] and in 2a [2.238(1) Å] are essentially the same. All
complexes show a nearly linear P‒Au‒Cl unit with similar P‒Au
and Au‒Cl distances of around 2.23 Å and 2.28 Å. In general,
the structures exhibit an antiperiplanar arrangement of the
two Au(I)Cl units with an almost ideal Au‒P‒P‒Au torsion
angles of 180°. Sole exception is the ortho methoxy
functionalized system 2d. Here, the two phosphine units are
twisted to each other with an Au‒P‒P‒Au torsion angle of only
139.1(2)°. This deviation is probably due to packing effects in
the crystal. Yet, also weak interactions of the methoxy groups
with the gold centers may play a role. The shortest O–Au
distance of 3.141(6) Å, however, is considerably longer than a
typical Au–O single bond (1.87 Å) and only slightly shorter than
the sum of the Van-der-Waals radii (3.18 Å).16 It is interesting
to note, that also for the o-NMe2 functionalized system 2e
such an orientation of the amino groups towards the gold
centre is observed in the crystal. However, these interactions
are somewhat different than those found in 2d. While in 2d
the closest Au–O interactions are found between the Au
center and the methoxy group bound to the two different
phosphorus atoms (e.g. Au2 and O2, Figure 2), the closest Au–
N contacts in 2e are found within one phosphine fragment.
The shortest Au–N distances in 2e amount to 2.929(9) Å and
are thus slightly shorter than the sum of the Van-der-Waals
radii (3.21 Å). Overall, the Au∙∙∙O and Au∙∙∙N contacts in 2d and
2e are only weak and have no impact on the P–Au–Cl angle.
Thereby, the 13C{1H} NMR spectra of
1 and 2 featured coupling
patterns of AA'X-systems. Hence, all signals, except that for the
para carbon atom, appear as pseudo-triplets due to the
different coupling constants to the two isochronic phosphorus
nuclei.
Scheme 1. Preparation of diphosphine bis(gold) complexes: i) Li/Cl carbenoid, rt, thf,
see ref. [6]; ii) (tht)AuCl, DCM, rt, 1h; quantitative conversion to 2.
Recording of high-resolution mass spectra of the complexes
2a-g were first attempted by electrospray ionization mass
spectrometry (ESIMS), which had most often been applied for
transition metal complexes.13 However, for none of the
2 | New J. Chem., 2015, 01, 1-4
This journal is © The Royal Society of Chemistry 2015
Please do not adjust margins

Page 3 of 9
New Journal of Chemistry
Please do not adjust margins
New Journal of Chemistry
ARTICLE
Table 1. Selected bond lengths and angles of the complexes 2.
View Article Online
DOI: 10.1039/C6NJ00786D
2a
2b
2c
Au–P [Å]
Au–Cl [Å]
P–P [Å]
Au–P–P–Au [°]
P–Au–Cl [°]
2.226(3)
2.280(3)
2.238(2)
178.4(2)
174.7(1)
2d
2.232(1)
2.286(1)
2.249(2)
180.0
174.4(1)
2e
2.229(1)
2.289(1)
2.240(3)
180.0
177.4(1)
2h
Au–P [Å]
Au–Cl [Å]
P–P [Å]
Au–P–P–Au [°]
P–Au–Cl [°]
P–Au–C15 [°]
2.242(2)
2.283(2)
2.268(3)
139.1(2)
177.3(1)
-
2.233(3)
2.297(3)
2.242(4)
179.0(1)
175.8(1)
-
2.276(1)
-
2.241(2)
180.0
-
171.1(1)
Crystal packing of diphosphine Au complexes. While all
complexes clearly showed no intramolecular aurophilic
interactions, intermolecular Au∙∙∙Au contacts still might be
important for the structure formation in the crystalline solid.17
While the lighter congeners, R3PCuX and R3PAgCl, usually form
oligomeric clusters through intermolecular M∙∙∙X bonding,
aggregation of the gold complexes has been found to occur
through a variety of intermolecular interactions including
Au∙∙∙X interactions, aurophilic Au∙∙∙Au and Au∙∙∙
 interactions
as well as C–H∙∙∙X, X∙∙∙ and ∙∙∙

 
interactions.18 Calculations
have shown that Au∙∙∙Au aurophilic interactions arise from
correlation and relativistic effects and can be comparable in
strength to hydrogen bonds.19 While Au∙∙∙Au interactions
supported by bridging ligands have often been observed,
unsupported interactions – particularly in phosphine Au(I)
halide or aryl complexes – have still only scarcely been
observed.8,20 In case of the ortho-functionalized systems 2d
and 2e the coordination sphere of gold is already fully
completed due to the weak additional coordination of the
anilinyl and anisolyl groups (vide supra). Thus, no distinct
intermolecular interactions are apparent in the crystal
structures. A different picture is observed for the structures of
the complexes 2a and 2b with the para-functionalized aryl
groups, which both exhibit layer structures in the solid state. In
the crystal packing of the p-tolyl substituted complex 2a
(Figure 3) the layers are formed through C–H∙∙∙Cl interactions
between the halide and the meta protons [2.959(2) Å] and the
methyl group [2.991(2) Å] of the tolyl groups. The interaction
between the layers are dominated by slipped face to face -
interactions between the tolyl substituents. The shortest C–C
distances between the phenyl groups in neighbouring layers
amount to 3.406 Å.21 The closest Au
–Au contacts amount to
4.648 Å and are thus too long to be regarded as attractive
aurophilic interactions. The contrary is true for the anisolyl
complex 2b (Figure 4). While, the layers are formed by slipped
face to face ∙∙∙ interactions (shortest C–C: 3.744 Å) as well as
Figure 2. Molecular structures of 2b, 2d and 2e. Displacement ellipsoids are drawn at
the 50% probability level. Hydrogen atoms and non-coordinating solvent molecules
(THF in 2d) are omitted for clarity. Selected bond lengths and angles are listed in Table
1. Crystallographic details for all structures are given in the ESI and the Experimental
Section.
C–H∙∙∙O hydrogen bonds, short Au–Au distances of 3.412 Å are
found between the layers. This indicates weak aurophilic
interactions.22 The spatial demand of the aryl substituents
probably prohibits a more dense packing of 2b and therefore
shorter Au
–Au distances. It has been shown that in general
This journal is © The Royal Society of Chemistry 2015
New J. Chem., 2015, 01, 1-4 | 3
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 4 of 9
ARTICLE
New Journal of Chemistry
Au∙∙∙Au contacts have highly specific angular geometries with
L–Au∙∙∙Au–L angles of 0/ 180° or
90°.[23] The Cl–Au∙∙∙Au'–Cl'
View Article Online
DOI: 10.1039/C6NJ00786D



angle of 96.6(1)° in 2b is well in this range for a staggered
conformation seen in many other Au(I) compounds. The crystal
packing of the anilinyl compounds 2c shows no regular layer
structure. This is due to the presence of dichloromethane
molecules in the crystal.
Figure 3. View of the crystal packing of 2a along the a-axis (hydrogens omitted for
clarity; π∙∙∙ π interactions between layers are highlighted in red).
So far, only the p-OMe functionalized system exhibited Au∙∙∙Au
interactions in the solid state. However, the relatively long Au-
Au distances indicated an only weak interaction. Hence,
structure formation in the diphosphine bis(gold) complexes
seemed to be dominated by C–H∙∙∙X and
∙∙∙ interactions.
This suggested that also the weak Au∙∙∙Au interaction in 2b
should easily be compensated by other intermolecular
interactions such as
hypothesis substitution of the chloro substituent at gold by a
pentafluorophenyl group to enhance possible ∙∙∙
∙∙∙ or X∙∙∙ interactions. To test this


interactions was attempted. For this purpose, a solution of 1b
in dichloromethane was treated with 2 equivalents of
(tht)AuArF (ArF = pentafluorophenyl) freshly prepared from
(tht)AuCl and LiC6F5. After stirring for 1 h at room temperature
and washing with pentane the diphosphine bisgold(I) complex
2h was obtained as colorless solid in 88% yield (Scheme 2). The
31P{1H} NMR spectrum of 2h showed again the expected high-
field shift to 36.8 ppm compared to the free diphosphine
Figure 4. (Top) View of the crystal packing of 2b along the b-axis (hydrogens omitted for
clarity; Au∙∙∙Au interactions are highlighted in red). (bottom) Representation of on layer
in 2b (Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms
and p-OMe groups are omitted for clarity. Au‒Au contacts are marked with dashed
lines).
Single-crystals suitable for X-ray diffraction analysis were
grown by slow concentration of a saturated dichloromethane
solution of 2h. The compound crystallizes as monomeric
complex in the triclinic space group P-1. All important bond
lengths and angles are shown in Table 1. As in case of the AuCl
compounds 2a-g complex 2h features an almost linear
coordination geometry of the gold atom and an antiperiplanar
arrangement of the two Au(I)Cl units. In the crystal, again a
1
ligand. The H and 19F{1H} NMR spectra featured all signals
expected for the compound. The 13C{1H} NMR spectrum
showed only broadened signals due to the coupling of the
carbon atoms with the phosphorus and fluorine nuclei. Yet,
fluorine decoupling allowed the assignment of all signals in the
13C{19F} NMR spectrum.
layer structure is formed via intermolecular C–H∙∙∙F hydrogen
bonds.24 However, in contrast to 2b no aurophilic Au∙∙∙Au
interactions (Au‒Au distance > 7.0 Å) are observed between
the layers, but slipped ∙∙∙ and F∙∙∙ interactions between the
stacked pentafluorophenyl groups.25 Hence, all penta-
fluorophenyl moieties are orientated parallel to each other
(distance: 3.556(2) Å) with a face-to-face/center-to-edge
Scheme 2. Preparation of bis(gold) complex 2h.
4 | New J. Chem., 2015, 01, 1-4
This journal is © The Royal Society of Chemistry 2015
Please do not adjust margins

Page 5 of 9
New Journal of Chemistry
Please do not adjust margins
New Journal of Chemistry
conformation (Figure 5). This suggests that these
ARTICLE

-inter- functional groups and the gold centres determined the
View Article Online
DOI: 10.1039/C6NJ00786D
actions are stronger than alternative aurophilic interactions as structure formation. No ordered 3-dimensional networks are
found in 2b
.
observed. In contrast, the para-functionalized compounds
exhibit regular layer structures, predominately formed via
intermolecular ∙∙∙ interactions and hydrogen bonds. In case
of the p-OMe substituted AuCl complex additionally un-
supported aurophilic Au∙∙∙Au interactions are observed. These
weak interactions however, were compensated by
∙∙∙
interactions upon replacement of the chloro ligand by a
pentafluorophenyl group. This study shows that structure
formation in aryl substituted diphosphine bisgold(I) complexes
aurophilic Au∙∙∙Au interactions only play a minor role
compared to ∙∙∙ interactions and hydrogen bonds.
Experimental section
General Methods. All experiments were carried out under a
dry, oxygen-free argon atmosphere using standard Schlenk
techniques. Involved solvents were dried over sodium or
1
potassium and distilled prior to use. H, 13C{1H}, 19F{1H} and
31P{1H} NMR spectra were recorded on Avance-500
spectrometers at 22 °C if not stated otherwise. All values of
the chemical shift are in ppm regarding the δ-scale. All spin-
spin coupling constants (J) are printed in Hertz (Hz). To display
multiplicities and signal forms correctly the following
abbreviations were used: s = singlet, pt = pseudotriplet, m =
multiplet, br = broad signal. Signal assignment was supported
by DEPT and HMQC experiments. APCI-MS spectra were
collected on an ExactiveTM Plus Orbitrap Mass Spectrometer
from Thermo Scientific. APCI-MS conditions involve a flow rate
of 0.02-0.1 mL min-1, a temperature of 400° C, and a corona
discharge current of 4μA (positive mode) and 5μA (negative
mode). Dichloromethane was used as the analyte solvent and
to generate the reagent ions. ESI-MS experiments were run
with 3.80 kV (positive mode) and 3.00 kV (negative mode). All
reagents were purchased from Sigma-Aldrich, ABCR,
Rockwood Lithium or Acros Organics and used without further
27
purification. (tht)AuCl,26 (tht)AuArF
as well as the
diphosphines6 were prepared according to literature
procedures.
Syntheses
Figure 5. (top) Molecular structure of 2h. Displacement ellipsoids are drawn at the 50%
probability level. Hydrogen atoms are omitted for clarity. Selected bond lengths and
angles are given in Table 1. (bottom) View of the crystal packing of 2h; π∙∙∙π
interactions are highlighted in red.
General procedure for the gold complexes 2a-g. The corres-
ponding diphosphine and 2 equiv. (tht)AuCl were dissolved in
dichloromethane and stirred for 1h at room temperature.
After removal of the solvent in vacuo pentane (10 mL) was
added to the yellowish solid and the suspension stirred for
several minutes. The solution was removed with a syringe and
the washing process was repeated two times. After drying in
vacuo the diphosphine gold complex could be isolated as
colourless or light grey solid.
Conclusions
In summary, we have reported the preparation of a series of
ortho and para functionalized diphosphine bisgold(I) com-
plexes from the corresponding diphosphine ligands and AuCl
precursors. The molecular structures of all complexes were
determined by single-crystal X-ray diffraction analysis to study
the importance of unsupported aurophilic interactions for the
structure formation of these compounds. In the solid state, no
dimerization of the complexes via Au∙∙∙Au contacts was
observed, as has been reported for ligands geometrically en-
forcing aurophilic interactions. In the ortho-substituted sys-
tems (OMe and NMe2) weak interactions between the
This journal is © The Royal Society of Chemistry 2015
New J. Chem., 2015, 01, 1-4 | 5
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 6 of 9
ARTICLE
New Journal of Chemistry
Figure 6. General numbering scheme of the diphosphine complexes 2.
MHz, CD2Cl2):
 = 55.9 (C-1),
View Article Online
DOI: 10.1039/C6NJ00786D
115.4 (m; C-4), 118.0 (br m; C-
2), 137.4 (m; C-3), 137.7 (C-8),
139.6 (C-9), 149.0 (C-7), 163.2
(C-5), C-6 not detectable.
19F{1H} NMR: (470.5 MHz,
Complex 2a. The complex was prepared according to general
1
procedure. Yield: 94%. H NMR: (500.1 MHz, CD2Cl2):
 = 2.40
(s, 12H; CH3), 7.27-7.30 (m, 8H; CH-4), 7.68-7.73 (m, 8H; CH-3).
13C{1H} NMR: (125.8 MHz, CD2Cl2):
= 21.8 (C-1), 121.4 (pt; C-
2), 130.7 (pt; C-4), 135.4 (pt; C-3), 144.9 (pt; C-5). 31P{1H} NMR:
(202.5 MHz, CD2Cl2): = 29.5. Anal. Calcd. for HRMS (APCI):

CD2Cl2):
 = –162.8 (m; CF-8),

–158.8 (m, CF-9), –116.6 (m,
+
·
CF-7). 31P{1H} NMR: (202.5
Calcd for C28H28Au2Cl2P2 ([M] ): 890.0369; found: 890.0358.
Complex 2b. The complex was prepared according to general
MHz, CD2Cl2):
(APCI):

= 36.8. HRMS
1
procedure. Yield: 76%. H NMR: (500.1 MHz, CD2Cl2):
 = 3.85
Calcd for
+
·
(s, 12H; OCH3), 6.97-6.99 (m, 8H; CH-4), 7.75-7.79 (m, 8H; CH-
3). 13C{1H} NMR: (125.8 MHz, CD2Cl2):
= 56.1 (C-1), 115.4 (pt;
C-2), 115.6 (pt; C-4), 137.3 (pt; C-3), 164.0 (pt; C-5). 31P{1H}
NMR: (202.5 MHz, CD2Cl2): = 28.6. Anal. Calcd. for
C28H28Au2Cl2O4P2: Calc: C, 35.20; H, 2.95. Found: C, 33.06; H,
C40H28Au2F10O4P2 ([M] ): 1218.0629; found: 1218.0622.

Single crystal X-ray structure determination. Single crystals
were selected from a Schlenk flask or a vial under an argon
atmosphere and covered with an inert oil (perfluoropolyalkyl-
ether, ABCR chemicals). Data were collected on a Bruker APEX-
CCD (D8 three-circle goniometer) (Bruker AXS). Integration was
conducted with SAINT and an empirical absorption correction
(SADABS) was applied. The structures were solved by direct
methods and refined by full-matrix least-squares methods
against F2 (SHELXL-08).28 All non-hydrogen atoms were refined
with anisotropic displacement parameters. Hydrogen atoms
were placed in calculated positions and refined using the riding
model. Details about the structure refinements are given Table
S1 and S2 (Supporting Information). Crystallographic data
(including structure factors) have been deposited with the
Cambridge Crystallographic Data Centre as supplementary

+
·
3.54. HRMS (APCI): Calcd for C28H28Au2ClO4P2 ([M–Cl] ):
919.0477; found: 919.0469.
Complex 2c. The complex was prepared according to general
1
procedure. Yield: 96%. H NMR: (500.1 MHz, CD2Cl2):
 = 3.01
(s, 24H; N(CH3)2), 6.67-6.69 (m, 8H; CH-4), 7.63-7.67 (m, 8H;
CH-3). 13C{1H} NMR: (125.8 MHz, CD2Cl2):
= 40.2 (C-1), 109.1
(pt; C-2), 112.3 (pt; C-4), 136.7 (pt; C-3), 153.2 (pt; C-5). 31P{1H}
NMR: (202.5 MHz, CD2Cl2): = 26.7. HRMS (APCI): Calcd for


+
·
C32H41Au2Cl2N4P2 ([M+H] ): 1007.1509; found: 1007.1495.
Complex 2d. The complex was prepared according to general
1
procedure. Yield: 94%. H NMR: (500.1 MHz, CD2Cl2):
 = 3.57
(s, 12H; OCH3), 6.70-6.72 (m, 4H; CH-7), 6.98-7.02 (m, 4H; CH-
publication no. CCDC-1463741-1463748. Copies of the data
can be obtained free of charge on application to Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
5), 7.40-7.43 (m, 4H; CH-6), 8.04-8.09 (m, 4H; CH-4). 13C{1H}
NMR: (125.8 MHz, CD2Cl2):  = 55.4 (C-1), 111.5 (pt; C-7), 115.9
(pt; C-3), 120.9 (pt; C-5), 134.4 (C-6), 136.4 (pt; C-4), 160.6 (pt;
CB2 1EZ,
UK;
[fax:
(+44) 1223-336-033;
email:
C-2). 31P{1H} NMR: (202.5 MHz, CD2Cl2):
Calcd for C28H28Au2ClO4P2 ([M–Cl] ): 919.0477; found:
 = 30.5. HRMS (APCI):
deposit@ccdc.cam.ac.uk].
+
·
Crystal data for compound 1d: C28H28O4P2; Mr = 490.44;
colourless plate; 0.26 x 0.16 x 0.04 mm3; monoclinic; space
919.0461.
Complex 2e. The complex was prepared according to general
group C2/c; a=14.3337(13), b=8.0972(7), c=21.2171(19)
Å;
1
β=91.838(3)°; V=2461.2(4) Å =0.210
3; Z=4; ρcalcd=1.324 gcm– ;
3
procedure. Yield: 60%. H NMR: (500.1 MHz, CD2Cl2):
 = 2.13
1
mm– ; F(000)=1032; T=100(2) K; R1=0.0545 and wR2=0.1157;
2523 unique reflections (θ < 26.42) and 156 parameters.
Crystal data for compound 1f: C28H28P2; Mr = 426.44;
colourless block; 0.26 x 0.21 x 0.13 mm3; monoclinic; space
(s, 24H; N(CH3)2), 7.25-7.29 (m, 4H; CH-5), 7.32-7.35 (m, 4H;
CH-7), 7.49-7.53 (m, 4H; CH-6), 8.19-8.23 (m, 4H; CH-4). 13C{1H}
NMR: (125.8 MHz, CD2Cl2):
(pt; C-5), 127.1 (pt; C-3), 133.6 (pt; C-6), 136.4 (pt; C-4), 158.8
(pt; C-2). 31P{1H} NMR: (202.5 MHz, CD2Cl2):
= 3.6. HRMS
 = 46.1 (C-1), 125.6 (pt; C-7), 127.0

group P21/c; a=7.5386(3), b=16.2636(7), c=18.9268(8)
Å;
+
·
3
(APCI): Calcd for C32H41Au2Cl2O4P2 ([M+H] ): 1007.1509: found:
1007.1509;
β=100.154(1)°; V=2284.17(17)
Å
3; Z=4; ρcalcd=1.240 gcm– ;
1

=0.203 mm– ; F(000)=904; T=100(2) K; R1=0.0431 and
wR2=0.0871; 4701 unique reflections (θ < 26.44) and 257
parameters.
Complex 2f. The complex was prepared according to general
procedure. Yield: 86%. Due to the low solubility no
characterization via NMR spectroscopy was possible. HRMS
(APCI): elemental analysis calcd for C28H28Au2Cl2P2 ([M] ):
890.0369; found: 890.0351.
Crystal data for compound 2a: C28H28Au2Cl2P2; Mr = 891.28;
+
·
colourless block; 0.34 x 0.22 x 0.17 mm3; orthorhombic; space
group Pca21; a=11.5426(8), b=16.0408(11), c=14.5815(11)
Å;
V=2699.8(3)
Å 
3; Z=4; ρcalcd=2.193 gcm– ; =11.188 mm– ;
3
1
Complex 2g. The complex was prepared according to general
F(000)=1672; T=100(2) K; R1=0.0232 and wR2=0.0482; 4745
unique reflections (θ < 24.99) and 264 parameters.
procedure. Yield: 94%.
Due to the low solubility no
characterization via NMR spectroscopy was possible. HRMS
(APCI): elemental analysis calcd for C24H20Au2ClP2 ([M–Cl] ):
799.0054; found: 799.0031.
Complex 2h. The complex was prepared according to general
procedure using (tht)AuArF instead of (tht)AuCl. Yield: 88%. H
+
·
Crystal data for compound 2b: C28H28Au2Cl2O4P2; Mr = 955.28;
colourless needle; 0.16 x 0.12 x 0.08 mm3; monoclinic; space
group C2/c; a=15.401(2), b=12.9857(19), c=14.468(3)
Å;
1
β=100.885(6)°; V=2841.4(8) Å3
;
Z=4; ρcalcd=2.233 gcm– ;
3

=10.649 mm– ; F(000)=1800; T=100(2) K; R1=0.0285 and
1
NMR: (500.1 MHz, CD2Cl2):  =  = 3.82 (s, 12H; CH3), 6.94-6.96
(m, 8H; CH-4), 7.86-7.89 (m, 8H; CH-3). 13C{19F} NMR: (125.8
6 | New J. Chem., 2015, 01, 1-4
This journal is © The Royal Society of Chemistry 2015
Please do not adjust margins

Page 7 of 9
New Journal of Chemistry
Please do not adjust margins
New Journal of Chemistry
ARTICLE
wR2=0.0412; 2502 unique reflections (θ < 25.00) and 174
parameters.
View Article Online
DOI: 10.1039/C6NJ00786D
Int. Ed. 2001, 40, 4694. (i) H. Schneider, D. Schmidt, U.
Radius, Chem. Commun. 2015, 51, 10138.
Crystal data for compound 2c: C34H44Au2Cl6N4P2; Mr
1177.31; colourless needle; 0.19 x 0.15 x 0.03 mm3; triclinic;
space group ; a=10.3579(7), b=10.4563(7), c=11.1637(7)
α=62.997(2)°, β=68.316(2)°, γ=78.142(2)°; V=1000.00(11) Å3
=
3
4
For reviews, see: (a) S. Greenberg and D. W. Stephan, Chem.
Soc. Rev. 2008, 37, 1482–1489. (b) R. J. Less, R. L. Melen, V.
Naseri and D. S. Wright, Chem. Commun. 2009, 4929. (c) D.
W. Stephan, Angew. Chem. Int. Ed. 2000, 39, 314. (d) R.
Waterman, Dalton Trans. 2009, 18.
P
Å;
;
3
1
Z=1; ρcalcd=1.955 gcm– ; =7.838 mm– ; F(000)=566; T=100(2)

K; R1=0.0351 and wR2=0.0548; 3508 unique reflections (θ <
(a) R. Tian, Y. Mei, Z. Duan and F. Mathey, Organometallics,
2013, 32, 5615. (b) M. W. Bezpalko, B. M. Foxman and C. M.
Thomas, Inorg. Chem. 2013, 52, 12329. (c) M. P. Duffy, L. Y.
Ting, L. Nicholls, Y. Li, R. Ganguly and F. Mathey,
Organometallics 2012, 31, 2936. (d) A. I. Arkhypchuck, M.-P.
Santoni and S. Ott, Organometallics, 2012, 31, 1118. (e) J.
Forniés, C. Fortuño, S. Ibáñez, A. Martín, A. C. Tsipis and C. A.
Tsipis, Angew. Chem. Int. Ed. 2005, 44, 2407. (f) J. J.
Weigand, N. Burford and A. Decken, Eur. J. Inorg. Chem.
2008, 4343. (g) B. Wang, K. A. Nguyen, G. N. Srinivas, C. L.
Watkins, S. Menzer, A. L. Spek and K. Lammertsma,
Organometallics 1999, 18, 796. (h) M. Scheer, S. Gremler and
E. Herrmann, J. Organomet. Chem. 1991, 414, 337. (i) Y.-F.
Yu, C.-N. Chau, A. Wojcicki, M. Calligaris, G. Nardin and G.
Balducci, J. Am. Chem. Soc. 1984, 106, 3705.
25.00) and 221 parameters.
Crystal data for compound 2d: C32H36Au2Cl2O5P2; Mr
1027.38; colourless needle; 0.26 x 0.09 x 0.06 mm3; triclinic;
space group ; a=10.9838(5), b=12.5329(6), c=13.3045(6)
α=77.741(2)°, β=80.078(2)°, γ=75.775(2)°; V=1720.84(14) Å3
=
P
Å;
;
3
1
Z=2; ρcalcd=1.983 gcm– ; =8.801 mm– ; F(000)=980; T=100(2)

K; R1=0.0536 and wR2=0.0909; 6032 unique reflections (θ <
24.99) and 368 parameters.
Crystal data for compound 2e: C32H40Au2Cl2N4P2; Mr
=
1007.45; colourless plate; 0.26 x 0.14 x 0.03 mm3; triclinic;
space group
P
; a=11.4972(5), b=15.3421(7), c=21.1914(10)
Å
;
;
α=94.108(2)°, β=90.027(2)°, γ=92.970(2)°; V=3700.0(3) Å3
5
(a) S. J. Geier and D. W. Stephan, Chem. Commun. 2008, 99
(b) D. Rehder and H. C. Bechthold, Z. Naturforsch. 1984, 38b
.
,
Z=4; ρcalcd=1.797 gcm– ;

=8.127 mm– ; F(000)=1928; T=100(2)
3
1
K; R1=0.0488 and wR2=0.0911; 13083 unique reflections (θ <
323. (c) J. D. Korp, I. Bernal, J. L. Atwood, W. E. Hunter, F.
Calderazzo, D. Vitali, J. Chem. Soc., Chem. Commun. 1979,
576. (d) J. L. Atwood, J. K. Newell, W. E. Hunter, I. Bernal, F.
Calderazzo, I. P. Mavani and D. Vitali, J. Chem. Soc., Dalton
Trans. 1978, 1189. (e) I. Bernal, J. D. Korp, F. Calderazzo, R.
Poli and D. Vitali, J. Chem. Soc., Dalton Trans. 1984, 1945. (f)
H. Baumgartner, H. Johannson and D. Rehder, Chem. Ber.
1979, 112, 2650. (g) A. J. M. Caffyn, M. J. Mays, G. A. Solan,
D. Braga, P. Sabatino, G. Conole, M. McPartlin and H. R.
Powell, J. Chem. Soc., Dalton Trans. 1991, 3103. (h) A. J. M.
Caffyn and M. J. Mays, J. Organomet. Chem. 2005, 690, 2209.
(i) Y. Miyake, Y. Nomaguchi, M. Yuki, Y. Nishibayashi,
Organometallics 2007, 26, 3611.
(a) S. Molitor, J. Becker and V. H. Gessner, J. Am. Chem. Soc.
2014, 136, 15517. (b) S. Molitor and V. H. Gessner, Synlett
2015, 26, 861.
Reviews on gold chemistry: (a) S. M. A. Sohel and R.-S. Liu,
Chem. Soc. Rev. 2009, 38, 2269. (b) E. Jiménez-Núñez, A. M.
Echavarren, Chem. Rev. 2008, 108, 3326. (c) A. S. K. Hashmi,
Angew. Chem. Int. Ed. 2010, 49, 5232. (d) A. S. K. Hashmi,
Acc. Chem. Res. 2014, 47, 864.
25.00) and 767 parameters.
Crystal data for compound 2h: C40H28Au2F10O4P2; Mr
=
1218.50; colourless needle; 0.15 x 0.11 x 0.02 mm3; triclinic;
space group
P
; a=7.3242(5), b=11.2949(8), c=13.0454(9)
Å
;
;
α=110.027(2)°, β=105.628(2)°, γ=93.035(2)°; V=963.80(12) Å3
Z=1; ρcalcd=2.099 gcm– ;

=7.776 mm– ; F(000)=578; T=100(2)
3
1
K; R1=0.0247 and wR2=0.0530; 3400 unique reflections (θ <
24.99) and 246 parameters.
Acknowledgements
6
7
This work was supported by the Deutsche Forschungs-
gemeinschaft (Emmy-Noether Grant DA1402/1-1) and the
Fonds der Chemischen Industrie. We are also grateful to the
Institut für Anorganische Chemie and the service teams for
scientific support.
8
9
(a) H. Schmidbaur and A. Schier, Chem. Rev. 2012, 41, 370.
(b) H. Schmidbaur, S. Cronje, B. Djordjevic and O. Schuster,
Chem. Phys. 2005, 311, 151.
(a) R. Gavara, J. Llorca, J. C. Lima and L. A. Rodriguez, Chem.
Commun. 2013, 49, 72. (b) M. Baron, C. Tubaro, A. Biffis, M.
Basato, C. Graiff, A. Poater, L. Cavallo, N. Armaroli and G.
Accorsi, Inorg. Chem. 2012, 51, 1778. (c) M. A. Rawashdeh-
Notes and references
1
2
C. A. Tolman, Chem. Rev. 1977, 77, 313–48.
(a) F. García, R. J. Less, V. Naseri, M. McPartlin, J. M. Rawson,
M. S. Tomas and D. S. Wright, Chem. Commun. 2008, 859–
861. (b) M. A. Beswick, N. Choi, A. D. Hopkins, M. McPartlin,
M. E. G. Mosquera, P. R. Raithby, A. Rothenberger, D. Stalke,
A. J. Wheatley and D. S. Wright, Chem. Commun. 1998,
2485–2486. (c) A. D. Bond, A. Rothenberger, A. D. Woods, D.
S. Wright, Chem. Commun. 2001, 525–526. (d) V. Naseri, R. J.
Less, R. E. Mulvey, M. McPartlin and D. S. Wright, Chem.
Commun. 2010, 46, 5000. (e) M. C. Fermin and D. W.
Stephan, J. Am. Chem. Soc. 1995, 117, 12645. (f) J. D.
Masuda, A. J. Hoskin, T. W. Graham, C. Beddie, M. C. Fermin,
N. Etkin and D. W. Stephan, Chem. Eur. J. 2006, 12, 8696. (g)
R. Waterman and T. D. Tilley, Angew. Chem. Int. Ed. 2006,
45, 2926. (h) V. P. W. Bohm and M. Brookhart, Angew. Chem.
Omary,
J. M. López-de-Luzuriaga, M. D. Rashdan, O.
Elbjeirami, M. Monge,M. Rodríguez-Castillo, and A. Laguna, J.
Am. Chem. Soc. 2009, 131, 3824.
10 (a) Y. Teramoto, K. Kubo and T. Mizuta, J. Organomet. Chem.
2011, 696, 3402. (b) M. Baba and T. Mizuta, Polyhedron
2015, 92, 30. (c) Y. Teramoto, K. Kubo, S. Kume and T.
Mizuta, Organometallics 2013, 32, 7014. (d) Y. Tanimoto, Y.
Ishizu, K. Kubo, K. Miyoshi and T. Mizuta, J. Organomet.
Chem. 2012, 713, 80.
11 For a similar cis-arrangement, see: D. Tofan and C. C.
Cummins, Chem. Sci. 2012, 3, 2474.
12 Elemental analyses consistently showed strongly varying
results in repeating measurements of the same sample.
This journal is © The Royal Society of Chemistry 2015
New J. Chem., 2015, 01, 1-4 | 7
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 8 of 9
ARTICLE
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ00786D
Often low values for C were measured although all other
spectroscopic studies indicated no further impurities.
13 R. Jirásko and M. Holčapek, Mass Spec. Rev. 2011, 30, 1013.
14 APCI-MS used for metal complexes: (a) S. Ogo, N. Makihara
and Y. Watanabe, Organometallics 1999, 18, 5470. (b) W. J.
Evans, K. A. Miller, J. W. Ziller and J. Greaves, Inorg. Chem.
2007, 46, 8008. (c) M. Shahid, M. Mazhar, M. Hamid, M.
Zeller, P. O'Brien, M. A. Malik, J. Raftery and A. D. Hunter,
New. J. Chem. 2009, 33, 2241.
15 (a) A. Kreienbrink, P. Lönnecke, M. Findeisen and E. Hey-
Hawkins, Chem. Commun. 2012, 48, 9385. (b) C. Charriere, F.
Mathey, F. Robert and Y. Jeannin, J. Chem. Soc., Chem.
Commun., 1984, 1707; (c) N. Meigrot, L. Ricard, C. Charrier
and F. Mathey, Angew. Chem., Int. Ed. Engl. 1990, 29, 534;
(d) G. Sillett, L. Ricard, C. Patois and F. Mathey, J. Am. Chem.
Soc., 1992, 114, 9453. (e) B. Hoge, C. Thösen and I.
Pantenburg, Chem. Eur. J. 2006, 12, 9019.
16 P. Pyykkö and M. Atsumi, Chem. Eur. J. 2009, 15, 186.
17 K. M. Anderson, A. E. Goeta and J. W. Steed, Inorg. Chem.
2007, 46, 6444-6451.
18 (a) N. A. Barnes, K. R. Flower, S. M. Godfrey, P.A. Hurst, R. Z.
Khan and R. G. Pritchard, Cryst. Eng. Comm. 2010, 12, 4240;
(b) I. Dance and M. Scudder, Cryst. Eng. Comm. 2009, 11
,
2233. (c) Q. L. Ni, X.-F. Jiang, T.-H. Huang, Y.-J. Wang, L.-C.
Gui and K.-G. Yang, Organometallics 2012, 31, 2343.
19 (a) P. G. Jones, Gold Bull. 1981, 14, 102–118; (b) P. G. Jones,
Gold Bull., 1986, 19, 46–57; (c) F. Scherbaum, A. Grohmann,
B. Huber, C. Kruger and H. Schmidbaur, Angew. Chem., Int.
Ed. Engl., 1988, 27, 1544; (d) H. Schmidbaur, Gold Bull.,
1990, 23, 11–16; (e) Schmidbaur, Chem. Soc. Rev., 1995, 24
391.
,
20 For examples, see: (a) K. R. Flower, A. T. McGown, P. J. Miles, R.
G. Pritchard and J. E. Warren, Dalton Trans. 2010, 39. 3509. (b)
U. Monkowius and M. Zabel, Acta Crystallogr., Sect. E: Struct.
Rep. Online, 2008, 64, m196.
21 C. Janiak, Dalton Trans. 2000, 3885–3896.
22 M. Streitberger, A. Schmied and E. Hay-Hawkins, Inorg.
Chem. 2014, 53, 6794.
23 S. S. Pathaneni, G. R. Desiraju, J. Chem. Soc., Dalton Trans.
1993, 319-322.
24 Examples for C
–H∙∙∙F hydrogen bonds: (a) S. Mohri, S. Ohisa,
K. Isozaki, N. Yonezawa, A. Okamoto, Acta Cryst., 2015, C71
,
344-350; (b) H. D. Choi, P. J. Seo, U. Lee, Acta Cryst., 2012,
E68, o339.
25 F. Ponzini, R. Zagha, K. Hardcastle, J. S. Siegel, Angew. Chem.
Int. Ed. 2000, 39, 2323-2325.
26 A. S. K. Hashmi, I. Braun, M. Rudolph, F. Rominger,
Organometallics, 2012, 31, 644–661.
27 T. Lauterbach, M. Livendahl, A. Rosellón, P. Espinet, A. M.
Echavarren, Org. Lett., 2010, 13, 3006–3009.
28 (a) SAINT v7.68A in Bruker APEX v2011.9, Bruker AXS Inst. Inc.:
Madison, WI, USA, 2008; (b) Sheldrick, G. M. SADABS 2008/2;
Universität Göttingen: Germany, 2008; (c) Sheldrick, G. M. Acta
Crystallogr., Sect. A 1990, 46, 467–473; (d) Sheldrick, G. M. Acta
Crystallogr., Sect. A 2008, 64, 112–122.
8 | New J. Chem., 2015, 01, 1-4
This journal is © The Royal Society of Chemistry 2015
Please do not adjust margins

Page 9 of 9
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ00786D
A series of diphosphine bis(gold) complexes were synthesised and the importance of
aurophilic interactions for their structure formation was studied.