Complexes of gold(I) with a chiral diphosphine ligand: A polymer with both Au···Ag and Ag···Ag metallophilic bonds

Article abstract of DOI:10.1515/znb-2009-11-1230

The chemistry of gold(I) with the ligand binap = 2,2′- bis(diphenylphosphino)-1,1′-binaphthyl is reported. Reaction of [Au ₂Cl₂(μ-binap)] with silver trifluoroacetate gave the corresponding complex [Au₂(O₂CCF₃) ₂(μ-binap)], and crystallization in the presence of excess silver trifluoroacetate gave the unusual syndiotactic polymeric complex [{Au ₂Ag₂(μ-O₂CCF₃) ₄(μ-binap)}_n], which contains both Au·· ·Ag and Ag···Ag metallophilic bonds. The trifluoroacetate ligands in [Au₂(O₂CCF₃) ₂(μ-binap)] can be replaced by nitrogen or phosphorus donor ligands to give complexes [Au₂(κ¹-4,4′- bipyridine)₂(μ-binap)](CF₃CO₂)₂ or meso-[Au₂(μ-binap)₂](CF₃CO ₂)₂.

Full text of DOI:10.1515/znb-2009-11-1230

Complexes of Gold(I) with a Chiral Diphosphine Ligand:
A Polymer with Both Au···Ag and Ag···Ag Metallophilic Bonds
Craig A. Wheaton, Michael C. Jennings, and Richard J. Puddephatt
Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7
Reprint requests to Dr. R. J. Puddephatt. E-mail: pudd@uwo.ca
Z. Naturforsch. 2009, 64b, 1469 – 1477; received August 14, 2009
Dedicated to Professor Hubert Schmidbaur, the grand master of gold chemistry, on the occasion of
his 75th birthday
The chemistry of gold(I) with the ligand binap = 2,2ꢀ-bis(diphenylphosphino)-1,1ꢀ-binaphthyl is
reported. Reaction of [Au2Cl2(µ-binap)] with silver trifluoroacetate gave the corresponding complex
[Au2(O2CCF3)2(µ-binap)], and crystallization in the presence of excess silver trifluoroacetate gave
the unusual syndiotactic polymeric complex [{Au Ag2(µ-O2CCF ) (µ-binap)}n], which contains
both Au···Ag and Ag···Ag metallophilic bonds. T2he trifluoroaceta3te4ligands in [Au2(O2CCF3)2(µ-
binap)] can be replaced by nitrogen or phosphorus donor ligands to give complexes [Au2(κ1-4,4ꢀ-
bipyridine)2(µ-binap)](CF3CO2)2 or meso-[Au2(µ-binap)2](CF3CO2)2.
Key words: Gold, Diphosphine, Chiral, Aurophilic, Polymer
Introduction
Results and Discussion
Synthesis of gold(I) complexes of binap
The synthesis and characterization of chiral com-
plexes of gold is a topical subject [1], based on appli-
Some of the synthetic procedures are illustrated in
cations in asymmetric catalysis [2, 3], chiral nanoparti- Scheme 1. The complex [Au2Cl2(µ-binap)], 1, was
cles and clusters [4],and stereoregular molecular ma- readily prepared by displacement of dimethylsulfide
terials [5]. In studying stereoselective self-assembly from [AuCl(SMe2)] by the phosphorus donors of the
of polymeric and oligomeric gold(I) complexes, sev- binap ligand, by analogy with the method established
eral complexes of gold(I) both with the ligand binap = with other diphosphine ligands [7, 8]. The complexes
2,2ꢀ-bis(diphenylphosphino)-1,1ꢀ-binaphthyl were pre- 1a and 1b were prepared by using either S-binap or
pared and structurally characterized. The ligand bi- rac-binap as ligand. It is noted that the correspond-
nap has been used extensively in catalysis but less ing complex 1c, with R-binap, has been prepared in-
often in materials chemistry [2 – 6]; it usually acts dependently by a different route [3]. Reaction of 1b
as a chelate [6] but, in its known complexes with with silver trifluoroacetate gave insoluble silver chlo-
gold(I), it acts as a bridging ligand [3, 5]. Thus it ride and the corresponding digold(I) trifluoroacetate
had promise for extending studies of coordination complex 2. The trifluoroacetate ligands in 2 are bound
macrocycles and polymers of gold(I) by forming chi- sufficiently strongly to give a stable complex, but suf-
ral derivatives [5, 7, 8]. One of the complexes described ficiently weakly that they can be displaced by 4,4ꢀ-
below is a mixed gold(I)-silver(I) complex which con- bipyridine to give the complex [Au2(κ1-4,4ꢀ-bipy)2(µ-
tains both Au···Ag and Ag···Ag metallophilic bonds binap)](CF3CO2)2, 3. Finally, reaction of 2 with rac-
in a syndiotactic polymer. The field of metallophilic binap gave crystals of the complex meso-[Au2(µ-
bonding has been pioneered by the experimental re- binap)2](CF3CO2)2, 4a. Most of the complexes gave
search of Schmidbaur and by the theoretical work of singlet resonances in the 31P NMR spectra (δ(31P) =
Pyykko¨ [9], while Schmidbaur has also discovered in- 24.71, 18.41, and 18.45 in 1, 2 and 3, respectively), but
teresting examples of Au···Ag metallophilic bonds complex 4 gave two broader resonances at δ(31P) =
[10] and general interest in metalophilic bonding con- 41.2 and 43.1 in relative ratio 1.5 : 1. The product of
tinues to grow [1, 9 – 13].
the similar reaction using S-binap gave only the reso-
c
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C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
Fig. 1. The structure of complex 1a. Hydrogen atoms and a
dichloromethane molecule are excluded for clarity. Selected
˚
bond parameters (A, deg): Au(1)–Cl(1) 2.282(3), Au(1)–P(1)
2.227(3); P(1)–Au(1)–Cl(1) 175.2(1). Symmetry equivalent
half molecules: x, y, z; 1−x, y, 1−z.
Scheme 1. (P = PPh2).
nance at δ(31P) = 43.1, so this resonance is assigned
to the S,S isomer 4c. Statistically, the reaction using
rac-binap would give 4a : 4b : 4c = 2 : 1 : 1 and, be-
cause 4b and 4c will have identical NMR spectra,
this would lead to the presence of two equal-intensity
resonances. The observed intensity ratio of 1.5 : 1 for
4a : 4b + 4c indicates a modest selectivity for the
meso-4a over racemic-4b + 4c. Crystallization gave
only 4a.
Fig. 2. The supramolecular hexameric structure of complex
1b. Only the ipso carbon atoms of phenyl groups are shown,
and solvent molecules and hydrogen atoms are omitted for
Structures of binap complexes of gold(I)
˚
clarity. Selected bond lengths and angles (A, deg): Au(1)–
The structure of the chiral gold(I) complex 1a, pre-
pared from S-binap and [AuCl(SMe2)], is shown in
Fig. 1. The asymmetric unit contains only half of the
molecule, with the symmetrically equivalent half gen-
erated by a C2 rotation. Therefore the two AuCl vec-
tors are oriented away from each other in an anti
conformation. As expected, the gold(I) coordination
Cl(1) 2.299(2), Au(1)–P(1) 2.235(2), Au(2)–Cl(2) 2.277(3),
Au(2)–P(2) 2.232(2); P(1)–Au(1)–Cl(1) 176.64(9), P(2)–
Au(2)–Cl(2) 174.77(10).
ring of the neighboring molecule, at a distance of ap-
˚
proximately 2.6 A.
The structure of 1b is shown in Fig. 2. In this
geometry is approximately linear, with the bond an- case, the asymmetric unit contains one full molecule
gle P–Au–N = 175.2(1)◦. The binaphthyl torsion an- of the complex but otherwise the molecular struc-
gle C(2)C(1)C(1A)C(2A) = 98.4(3)◦, only slightly dis- ture is similar to that of 1a. The rhombohedral unit
torted from orthogonality. The molecule contains no cell contains eighteen symmetry-related molecules,
gold···gold interactions, with an intramolecular con- with nine molecules of each enantiomer. The coor-
˚
tact of 5.42 A and shortest intermolecular separation dination geometry at gold(I) is approximately linear,
of 8.63 A. The most significant intermolecular contact with bond angles P–Au–Cl = 174.8(1)◦ and 176.64(9)◦
˚
is a C–H···π interaction involving a C(4)–H(4) unit for Au(2) and Au(1), respectively. No aurophilic in-
of each naphthalene ring acting as a donor to a phenyl teraction is present, with the shortest Au···Au con-
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C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
tact being the intramolecular distance Au(1)···Au(2) =
1471
˚
5.48 A. Through significant C–H···π stacking interac-
tions, in which one naphthalene ring of each molecule
acts as a donor as well as an acceptor, the molecules
are organized in groups of six into large ring struc-
tures (Fig. 2). The main intermolecular interaction in-
volves the C(9)H(9)···π interaction between naphthyl
˚
groups, with a contact distance of approximately 2.9 A.
The hexamer in Fig. 2 contains 3 molecules of each
enantiomer with alternating chirality RSRSRS. These
rings stack directly on top of one another, creating a
small channel which is occupied by disordered sol-
vent molecules. This remarkable difference between
the crystal packing of 1a and 1b is an excellent exam-
ple of chirality-directed self-assembly, showing how
supramolecular structures can be significantly altered
by variation of only the chiral features of the compo-
nents [14].
The structure of complex 2c, prepared by reaction
of 1b with silver trifluoroacetate, is depicted in Fig. 3.
The asymmetric unit contains two similar but inde-
pendent molecules of the complex. Each molecule is
chiral, but a crystallographic center of inversion gen-
erates the molecules of opposite chirality, thus giv-
ing a racemic mixture within the crystal. The molecu-
lar structure is similar to the chloride analogs 1a and
1b (Figs. 1 and 2), with approximately linear coor-
dination geometry at gold(I), and with the ligand bi-
naphthyl torsion angle C(11)C(20)C(40)C(31) = 101◦.
Fig. 4. Structure of the cationic complex 3. Hydrogen atoms
have been omitted, and only the ipso carbon atoms of
phenyl groups are shown for clarity. Selected bond param-
˚
eters (A, deg): Au(1)–N(61) 1.95(3), Au(1)–P(1) 2.174(10),
Au(2)–N(50) 1.95(3), Au(2)–P(2) 2.199(9); N(61)–Au(1)–
P(1) 174.2(6), N(50)–Au(2)–P(2) 179.0(7).
The intramolecular Au···Au distance, Au(1)Au(3) =
˚
3.966(2) A, is shorter than analogous distances in 1a
and 1b, but still outside the range of significant au-
rophilic attractions.
The structure of complex 3 is shown in Fig. 4. The
molecule contains two gold atoms with a bridging bi-
nap ligand and with a monodentate 4,4ꢀ-bipyridine lig-
and bound to each gold atom. The coordination at
gold(I) is close to the expected linear geometry (P–
Au–N = 174.2(6)◦, 179.0(7)◦). The trifluoroacetate an-
ions are not bound to gold(I), with the closest ap-
˚
proaches being Au···O = 3.56 and 4.14 A, and there is
no intramolecular Au···Au contact (Au(1)···Au(2) =
˚
4.66 A). The primary supramolecular interaction is
weak face-to-face π-π stacking between the non-
coordinated pyridine rings of adjacent molecules with
˚
an interaction distance of approximately 3.5 A. These
interactions occur in a head-to-tail fashion between
complexes of the same stereochemical configuration,
giving loosely associated isotactic sequences. The op-
posite enantiomers are generated through crystallo-
graphic symmetry in the racemic product.
Fig. 3. Molecular structure of one of the two indepen-
dent molecules of complex 2. Hydrogen atoms and sol-
vent molecules are omitted and only the ipso carbon atoms
of the phenyl rings are shown for clarity. Selected bond
The structure of the complex [Au2(µ-R-binap)(µ-
S-binap)](CF3CO2)2, 4a, is shown in Fig. 5. The unit
cell contains two similar but independent heterochi-
ral macrocycles, each containing one R-binap and one
S-binap ligand. There is a strong intramolecular au-
rophilic interaction, with the distance Au(1)···Au(2) =
˚
parameters (A, deg): Molecule 1: Au(1)–O(101) 2.06(1),
Au(1)–P(1) 2.209(5), Au(3)–O(301) 2.09(1), Au(3)–P(3)
2.211(5); O(101)–Au(1)–P(1) 174.0(4), O(301)–Au(3)–P(3)
171.8(4). Molecule 2: Au(2)–O(201) 2.05(1), Au(2)–P(2)
2.220(5), Au(4)–O(401) 2.08(1), Au(4)–P(4) 2.216(5);
O(201)–Au(2)–P(2) 177.8(4), O(401)–Au(4)–P(4) 176.3(4).
˚
2.8700(4) A in one macrocycle and Au(3)···Au(4) =
˚
2.9125(4) A in the other. The close Au···Au ap-
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1472
C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
Scheme 2. P = PPh2, R = CF3.
(a)
(b)
Fig. 5. One of two independent macrocycles in the struc-
ture of 4a. Hydrogen atoms, anions and solvent molecules
˚
are omitted for clarity. Selected bond parameters (A, deg):
Molecule 1: Au(1)–P(1) 2.332(2), Au(1)–P(3) 2.328(2),
Au(2)–P(2) 2.336(2), Au(2)–P(4) 2.323(2), Au(1)···Au(2),
2.8700(4); P(1)–Au(1)–P(3) 162.06(7), P(2)–Au(2)–P(4)
163.67(7). Molecule 2: Au(3)–P(5) 2.334(2), Au(3)–
P(6) 2.343(2), Au(4)–P(7) 2.319(2), Au(4)–P(8) 2.328(2),
Au(3)···Au(4) 2.9125(4); P(5)–Au(3)–P(6) 163.12(7), P(7)–
Au(4)–P(8) 164.52(7).
Fig. 6. Structure of the polymeric complex 5: (a) A view of
the asymmetric unit; (b) a section of the polymeric chain
with fluorine atoms and all but the ipso carbon atoms of
phenyl groups omitted for clarity. Selected bond parameters
˚
(A, deg): Au(1)–O(71) 2.058(5), Au(1)–P(1) 2.205(2),
Au(1)–Ag(3) 3.2989(9), Au(2)–O(81) 2.066(5), Au(2)–P(2)
2.209(2), Au(2)–Ag(4) 3.0373(8), Ag(3)–O(91) 2.201(6),
Ag(3)–O(92A) 2.207(6), Ag(3)–O(72) 2.380(6), Ag(3)–
Ag(3A) 2.938(1), Ag(4)–O(101) 2.179(6), Ag(4)–O(102B)
2.191(6), Ag(4)–O(82) 2.500(6), Ag(4)–Ag(4B) 2.973(1);
O(71)–Au(1)–P(1) 176.4(2), O(81)–Au(2)–P(2) 175.8(2),
proaches are accompanied by distortion of the gold(I)
centers from linearity, with angles P(1)–Au(1)–P(3) =
162.06(7)◦ and P(2)–Au(2)–P(4) = 163.67(7)◦. There
is no association between the anions and the gold
atoms, and there are no notable intermolecular inter-
actions.
O(91)–Ag(3)–O(92A)
161.1(2),
O(91)–Ag(3)–O(72)
101.5(2), O(92A)–Ag(3)–O(72) 96.7(2), Ag(3A)–Ag(3)–
Au(1) 141.23(4), O(101)–Ag(4)–O(102B) 156.9(2),
O(101)–Ag(4)–O(82) 109.5(2), O(102B)–Ag(4)–O(82)
93.4(2), Ag(4B)–Ag(4)–Au(2) 147.78(4).
A polymer with gold(I)-silver(I) metallophilic interac-
tions
[{Au2Ag2(O2CCF3)4(µ-binap)}n], 5 (Scheme 2). The
1H and 31P NMR spectra of 5 were very similar to
The reaction of complex 2 (Scheme 1) with ex-
cess silver trifluoroacetate gave the complex rac-
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C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
1473
ral ligands [5] and with metallophilic bonds [11, 13] as
part of the backbone. It should be noted that there are
several recent examples of complexes in which Ag2(µ-
O2CR)2 units form metallophilic bonds to gold(I), as
illustrated in Scheme 3 [12, 13]. Complex 5 forms
roughly linear Au···Ag···Ag···Au linkages, but com-
plex 6, in which C-N represents a pyridyl-carbene lig-
and, forms triangular AuAgAg units, while complex 7,
in which R = C6F5 and L = Ph3P=CH2, contains both
of the above structural units [13h, 13i].
Discussion
The conformation of the binap ligand can change by
rotation about either the central binaphthyl C–C bond
or about the phosphorus-carbon bonds, as illustrated
in Scheme 4. The binaphthyl torsion angle remains
fairly constant at approximately 90◦ in the complexes
studied, as discussed above, so the rotation about the
phosphorus-carbon bonds is the most important single
factor in determining the conformation. A useful pa-
rameter to define the binap conformation in the com-
plexes is the Au–P···P–Au torsion angle, which can
vary from 180◦ to 0◦, as illustrated in Scheme 4.
The Au–P···P–Au torsion angles for the complexes
1 – 5 range from 37 – 176◦, from which it is clear that
there is no very large barrier to rotation about the
Ph2P–C bonds. The complexes 1a, 1b, and 5 have the
most linear conformations, with Au–P···P–Au = 157,
176 and 172◦respectively. Complex 4 has the approx-
imately eclipsed conformation, with Au–P···P–Au
ranging from 37 – 57◦, as required for formation of
the macrocyclic structure. Complexes 2 and 3 have
intermediate values with torsion angles Au–P···P–
Au = 110 and 126◦, respectively. There are no obvious
constraints for the conformations of complexes 1 – 3
and 5, from which it can be concluded that there is
Scheme 3. Some complexes with Au···Ag metallophilic
bonds.
those of complex 2, indicating that the complex is
largely dissociated in solution. The structure of com-
plex 5 was determined and is shown in Fig. 6.
In the structure of complex 5, there are two
non-equivalent Ag2(µ-O2CCF3)2 units which bridge
between molecules of [Au2(O2CCF3)2(µ-binap)] by
forming, in each case, a weak Ag–O bond to a
carbonyl oxygen atom (Ag(3)–O(72) = 2.380(6),
(a)
(b)
˚
Ag(4)–O(82) = 2.500(6) A) and a metallophilic
Au···Ag bond (Au(1)–Ag(3) 3.2989(9), Au(2)–Ag(4)
˚
3.0373(8) A). The gold(I) centers (ignoring the metal-
metal interactions) are roughly linear (O(71)–Au(1)–
P(1) = 176.4(2), O(81)–Au(2)–P(2) 175.8(2)◦), while
the silver(I) centers have highly distorted trigonal or
T-shaped coordination (angles O–Ag–O range from
93.4– 156.9◦).
Fig. 6(b) shows that the complex 5 forms a syndio-
tactic coordination polymer with alternating RSRS···
chirality of the binap ligands. It is an unusual com-
pound, in the sense that it is a polymer with both chi-
Scheme 4. Conformations of the binap ligand.
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1474
C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
little steric hindrance within the torsion angle range (t, 2H, 7-H, binap), 6.66 (d, 2H, 8-H binap). – 31P NMR: δ =
Au–P···P–Au = 110 – 176◦. Within this range, the
24.71 (s).
Complex 1a was prepared by the same procedure from
gold atoms are well separated and do not form an
intramolecular aurophilic interaction, while steric
effects of the bulky binap ligands prevent formation
of intermolecular Au···Au bonds. In complex 5,
the smaller [Ag2(O2CCF3)2] units are able to form
metallophilic bonds of the form Au···Ag···Ag···Au.
For complex 4, the increase in steric strain in forming
the more eclipsed structure must be small enough
that it can be balanced by the bond energy gained in
forming the aurophilic attraction in the macrocyclic
complex. This relative freedom of rotation within
the binap ligand may be problematic in the use of
complexes such as 2 in chiral catalysis, because the
greatest selectivity tends to be observed when the
catalyst structure is relatively rigid [2, 3]. However,
the preference for the roughly linear conformation is
useful in forming polymeric gold(I) complexes from
the precursor complex 2 [5].
S-binap, giving similar yield and identical 1H NMR spectra.
[Au2(µ-binap)(CF3CO2)2], 2
Silver trifluoroacetate (40.6 mg, 0.184 mmol) was
added to a suspension of 1b (100 mg, 0.092 mmol) in
dichloromethane (10 mL). The mixture was stirred for
30 min and filtered through celite to remove silver chloride.
The solvent was removed, and the compound was purified
by reprecipitation from a concentrated dichloromethane so-
lution by addition of pentane. The precipitate was filtered,
washed with pentane, and dried under vacuum. Yield 0.102 g,
89 %. – Anal. for C48H32Au2F6O4P2: calcd. C 46.40;
H 2.60; found C 46.08, H 2.45. – 1H NMR (CD2Cl2):
δ(1H) = 8.10 (d, 2H, 4-H binap), 7.97 (d, 2H, 5-H binap),
7.63 (d, 2H, o-H Ph), 7.61 (d, 2H, o-H Ph), 7.57 – 7.35 (m,
12H, 3-H binap + 6-H binap + m-H Ph), 7.29 (t, 4H, p-H Ph),
7.19 (d, 2H, o-H Ph), 7.17 (d, 2H, o-H Ph), 7.00 (t, 2H, 7-H,
binap), 6.72 (d, 2H, 8-H binap). – 31P NMR: δ = 18.41(s).
Complex 5 was prepared similarly, but using silver triflu-
oroacetate (81.2 mg, 0.368 mmol). Yield: 95 mg, 61 %. –
Anal. for C52H32Ag2Au2F12O8P2: calcd. C 37.08, H 1.91;
found C 36.75, H 2.14. – NMR data are the same as for 2.
Experimental Section
NMR spectra were recorded using either a Varian Inova
400 NMR spectrometer or a Varian Mercury 400 NMR spec-
trometer. 1H and 13C chemical shifts are reported relative to
tetramethylsilane (TMS), while 31P chemical shifts are re-
ported relative to 85 % H3PO4 as an external standard. ESI
mass spectra were recorded using a Micromass LCT spec-
trometer and dichloromethane solutions of the compounds.
The 1H NMR labeling system is shown below for the binap
ligand.
[Au2(κ1-4,4ꢀ-bipy)2(µ-binap)](CF3CO2)2, 3
To a solution of 4,4ꢀ-bipy (28.7 mg, 0.184 mmol)
in CH2Cl2 (10 mL) was added
a filtered solution
of [Au2(µ-R,S-binap)(CF3CO2)2] (0.092 mmol), prepared
from [Au2(µ-R,S-binap)Cl2] (0.100 g, 0.092 mmol) and
AgO2CCF3 (0.041 g, 0.184 mmol) in CH2Cl2 (10 mL).
The solution was stirred for 2 h. The solvent was then re-
moved and the crude product dissolved in a minimum of
dichloromethane. The product was precipitated from solu-
tion as a white powder by addition of pentane, collected
by filtration, washed with diethyl ether and pentane, and
dried under vacuum. Yield: 0.0612 g, 42 %. – Anal. for
C68H48Au2P2N4O4F6: calcd. C 52.52, H 3.11, N 3.60;
[Au2(µ-R,S-binap)Cl2], 1b
found C 52.11, H 2.85, N 3.53. – 1H NMR (CD2Cl2
+
CD3OD): δ(1H) = 8.69 (s, 8H, o-H py), 8.08 (d, 2H, 4-H bi-
nap), 7.93 (d, 2H, 5-H binap), 7.63 (d, 2H, o-H Ph), 7.62 (d,
2H, o-H Ph), 7.57 (d, 8H, m-H py), 7.52 – 7.42 (m, 6H, 3-H
binap + 6-H binap + m-H Ph), 7.38 (t, 6H, m-H Ph), 7.22 (m,
4H, p-H Ph), 7.16 (d, 2H, o-H Ph), 7.14 (d, 2H, o-H Ph), 6.96
(t, 2H, 7-H, binap), 6.68 (d, 2H, 8-H binap). – 31P NMR: δ =
18.45 (s).
A solution of R,S-binap (0.304 g, 0.488 mmol) in ace-
tone (30 mL) was added to a suspension of [AuCl(SMe2)]
(0.283 g, 0.961 mmol) in acetone (60 mL). The mixture was
stirred for two hours to give a white precipitate, which was
collected by filtration, washed with acetone, diethyl ether,
and pentane, and dried under vacuum. Yield 0.381 g, 73 %. –
Anal. for C44H32Au2Cl2P2: calcd. C 48.60, H 2.97; found
C 48.29, H 2.73. – 1H NMR (CD2Cl2): δ(1H) = 8.20 (d, 2H,
4-H binap), 7.98 (d, 2H, 5-H binap), 7.65 (d, 2H, o-H Ph),
7.63 (d, 2H, o-H Ph), 7.56 – 7.45 (m, 6H, 3-H binap + 6-H
binap + m-H Ph), 7.45 – 7.35 (m, 6H, m-H Ph), 7.26 (d of t,
[Au2(µ-binap)2](CF3CO2)2, 4
To a solution of [Au2(µ-R,S-binap)(CF3CO2)2] (0.092
4H, p-H Ph), 7.19 (d, 2H, o-H Ph), 7.17(d, 2H, o-H Ph), 6.90 mmol) in tetrahydrofuran was added 58.5 mg (0.092 mmol)
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C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
1475
Table 1. Crystallographic data for the complexes.
Complex
Formula
1a·CH2Cl2
1b·0.93 (CH3)2SO 2·0.5 CH2Cl2
3·3 CH2Cl2
C71H54Au2-
Cl6F6N4O4P2
1809.80
150
0.71073
monoclinic
P21/n
16.853(8)
22.64(1)
18.407(7)
90
114.03(3)
90
4·0.74 CH2Cl2
C92.74H66.2Au2-
Cl1.48F6O4P4
1928.91
150
0.71073
5·1.5 CH2Cl2
C55H42Au2Cl4P2 C45.86H37.58Au2- C48.5H33Au2-
C53.5H35Ag2Au2-
Cl3F12O8P2
1811.78
Cl2O0.93P2S0.93
1160.18
150
ClF6O4P2
1285.07
150
Mr
1170.38
150
0.71073
monoclinic
C2
19.5457(8)
8.6328(3)
14.0179(5)
90
122.112(2)
90
T, K
150
0.71073
˚
λ, A
0.71073
rhombohedral
¯
R3
0.71073
triclinic
P1
Crystal system
Space group
triclinic
triclinic
¯
¯
¯
P1
P1
˚
a, A
30.199(1)
30.199(1)
28.2091(9)
90
90
120
11.9800(4)
15.5702(6)
24.4784(9)
74.579(2)
89.400(2)
74.197(2)
4225.8(3)
4
14.7650(3)
22.7024(5)
23.3878(5)
88.9490(8)
89.6320(8)
79.0320(9)
7695.1(3)
4
13.5887(5)
14.1199(5)
15.7540(6)
85.894(2)
86.299(2)
66.574(2)
2764.3(2)
2
˚
b, A
˚
c, A
α, deg
β, deg
γ, deg
3
˚
V, A
2003.4(1)
2
1.94
22279(1)
18
6414(2)
4
1.83
Z
Dcalc, Mg m−3
1.46
2.02
1.65
4.0
2.18
6.3
µ, mm−1
7.7
6.1
7.1
4.9
Data / restr. / param. 3328 / 1 / 241
x (Flack) 0.14(2)
8631 / 0 / 403
–
14616 / 1045 / 1043 5766 / 1353 / 801 26578 / 3384 / 1786 9724 / 677 / 710
–
–
–
–
R1 / wR2 [I ≥ 2σ(I)] 0.0408 / 0.1085
0.0542 / 0.1284
0.0804 / 0.1388
0.76 / −1.83
0.0781 / 0.1988
0.1143 / 0.2164
3.42 / −2.61
0.0938 / 0.2617 0.0500 / 0.1247
0.1895 / 0.3129 0.0633 / 0.1308
0.0440 / 0.0950
0.0748 / 0.1054
1.86 / −1.44
R1 / wR2 (all data)
∆ρfin (max−/ m3 in),
0.0421 / 0.1099
3.56 / −2.33
1.25 / −1.44
1.77 / −2.52
˚
e A
of R,S-binap. The solution was stirred for 2 h. The solvent [Au2(µ-S-binap)Cl2], 1a
was removed and the crude product dissolved in a mini-
Crystals of 1a were grown by slow diffusion of pentane
into a dichloromethane solution of the compound. The asym-
metric unit contains only one half of a structural unit of the
compound, the other being related by symmetry.
mum of dichloromethane. The product was precipitated from
solution as a white powder by addition of pentane, col-
lected by filtration, washed with diethyl ether and pentane,
and dried under vacuum. Yield: 0.172 g, 96 %. – Anal. for
C92H64Au2F6O4P4: calcd. C 59.24, H 3.46; found C 58.98,
H 3.54. – 31P NMR (CD2Cl2): δ = 41.16 (s); 43.07 (s, broad).
Single crystals of 4a were grown by slow diffusion of n-
hexane into a dichloromethane solution of the compound.
[Au2(µ-binap)Cl2], 1b
Crystals of 1b crystallized from a dimethylsulfoxide
(DMSO) solution of the compound. Voids in the lattice were
filled with disordered molecules of DMSO. The SQEEZE
procedure of the PLATON suite of programs [18] was used
X-Ray structure determinations
to account for this solvent electron density. A total of 701.7
Data were collected at low temperature (−123 ◦C) with a
3
˚
electrons were removed in a volume of 7299.9 A (32.8 % of
Nonius Kappa-CCD area detector diffractometer using COL-
the unit cell). These electrons are assigned to 16.7 molecules
of dimethylsulfoxide (This equates to 0.93 DMSO molecules
per asymmetric unit). The SQUEEZE-processed data were
used for all subsequent refinement cycles.
˚
LECT [15] software, with MoKα radiation (λ = 0.71073 A).
The unit cell parameters were calculated and refined from
the full data set. Crystal cell refinement and data reduc-
tion were carried out using HKL2000 DENZO-SMN [16].
The absorption correction was applied using HKL2000
DENZO-SMN (SCALEPACK) [16]. The SHELXTL [17] soft-
ware package was used to solve the structures by Direct
Methods, with subsequent refinement carried out using suc-
cessive difference Fouriers. All hydrogen atoms were cal-
culated geometrically as riding on their respective carbon
atoms. Crystal data are summarized in Table 1, and further
details of the structures can be found in the CIF files CCDC
743981–743986 deposited with The Cambridge Crystallo-
graphic Data Centre. These data can be obtained free of
charge via www.ccdc.cam.ac.uk/data request/cif.
[Au2(µ-binap)(CF3CO2)2], 2
Crystals of 2 were grown by slow diffusion of pentane
into a dichloromethane solution of the compound. There are
two distinct molecules in the asymmetric unit, and a solvent
CH2Cl2 molecule, which was restrained to have equal C–Cl
distances.
[Au2(κ1-4,4ꢀ-bipy)2(µ-binap)](CF3CO2)2, 3
Crystals of 3 were grown by slow diffusion of pentane
into a dichloromethane solution. The CH2Cl2 molecules of
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1476
C. A. Wheaton et al. · Complexes of Gold(I) with a Chiral Diphosphine Ligand
˚
solvation were restrained to have C–Cl = 1.65 A, and phenyl grams [18]. A total of 40.4 electrons were removed from
3
˚
groups were restrained to be ideal hexagons.
a volume of 159.7 A (2.1 % of the unit cell). These elec-
trons are assigned to 0.96 molecules of dichloromethane. The
SQUEEZE-processed date were used for all subsequent re-
finement cycles.
meso-[Au2(µ-R-binap)(µ-S-binap)](CF3CO2)2, 4a
Crystals of 4a were grown by slow diffusion of n-hexane
into a concentrated dichloromethane solution of the com-
pound 4. The asymmetric unit contains two similar but in-
dependent macrocyclic structures. Two of the four trifluo-
roacetate anions were disordered in which the -CO2 group
was modeled over two sites, one at 50 : 50 and the other at
60 : 40 occupancy. All atoms of the macrocycles were mod-
eled anisotropically with the exception of C144. Several an-
ion and solvent atoms were also not modeled anisotropi-
cally, including O304, O401, C404, F405, and C700. A sin-
gle small void in the lattice was assumed to be filled with
disordered dichloromethane solvent, and was accounted for
using the SQUEEZE procedure of the PLATON suite of pro-
[Au2Ag2(µ-O2CCF3)4(µ-R,S-binap)], 5
Crystals of [Au2Ag2(µ-O2CCF3)4(µ-R,S-binap)]·1.5-
CH2Cl2 were grown from a concentrated dichloromethane
chloride solution of 2 containing excess silver trifluoroac-
etate by slow diffusion of pentane. The C–Cl and Cl–Cl dis-
tances of the CH2Cl2 molecules were fixed.
Acknowledgement
We thank the NSERC (Canada) for financial support and
for a scholarship to C. A. W.
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