Hydroamination reactions catalyzed by [Au2(μ-Cl)(μ-bis(phosphino)ferrocene)][BArF24]

Article abstract of DOI:10.1016/j.jorganchem.2019.121049

1,1′-bis(phosphino)ferrocene ligands are commonly employed in a variety of catalytic systems. These ligands are of particular interest as the steric and electronic properties of the phosphorus donor atoms can be altered by changing the substituents of the

Full text of DOI:10.1016/j.jorganchem.2019.121049

Journal Pre-proof
Hydroamination reactions catalyzed by [Au (μ-Cl)(μ-bis(phosphino)ferrocene)]
2
[BArF
]
24
Sadie A. Wolfarth, Natasha E. Miner, Nicole E. Wamser, Reilly K. Gwinn, Benny C.
Chan, Chip Nataro
PII:
S0022-328X(19)30492-9
DOI:
https://doi.org/10.1016/j.jorganchem.2019.121049
JOM 121049
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 20 September 2019
Revised Date: 19 November 2019
Accepted Date: 25 November 2019
Please cite this article as: S.A. Wolfarth, N.E. Miner, N.E. Wamser, R.K. Gwinn, B.C. Chan, C. Nataro,
Hydroamination reactions catalyzed by [Au (μ-Cl)(μ-bis(phosphino)ferrocene)][BArF ], Journal of
2
24
Organometallic Chemistry (2019), doi: https://doi.org/10.1016/j.jorganchem.2019.121049.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition
of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of
record. This version will undergo additional copyediting, typesetting and review before it is published
in its final form, but we are providing this version to give early visibility of the article. Please note that,
during the production process, errors may be discovered which could affect the content, and all legal
disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.

Hydroamination reactions catalyzed by
[Au2(µ-Cl)(µ-
bis(phosphino)ferrocene)][BArF24]
Sadie A. Wolfarth,a,1 Natasha E. Miner,a,1 Nicole E. Wamser,a,2 Reilly K. Gwinn,a Benny C.
Chan,b and Chip Nataroa, *
aDepartment of Chemistry, Lafayette College, Easton, PA 18042 and bDepartment of Chemistry,
The College of New Jersey, Ewing, NJ 08628
* Corresponding author. Tel.: +1 610 330 5216; fax: +1 610 330 5714.
E-mail address: nataroc@lafayette.edu (C. Nataro).
1 These authors contributed equally to the work presented and the preparation of the manuscript.
2 Present address: Boehringer Ingelheim, Ridgefield, CT, 06879 .
Abstract
1,1'-bis(phosphino)ferrocene ligands are commonly employed in a variety of catalytic systems.
These ligands are of particular interest as the steric and electronic properties of the phosphorus
donor atoms can be altered by changing the substituents of the phosphines. In addition, the
ferrocene backbone of the ligands provides unique electronic and conformational flexibility to
these ligands. Previous investigations in this lab have examined catalytic ring closing reactions
using a series of gold compounds with bis(phosphino)ferrocene ligands, [Au2Cl2(µ-PP)]. These
gold compounds were shown to react with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate,
Na[BArF24], to generate a cationic species with the general formula [Au2(µ-Cl)(µ-PP)][BArF24]
that are much more efficient catalysts than the [Au2Cl2(µ-PP)] compounds. In this study, a series

of [Au
2
Cl (µ-PP)] (µ-PP = 1,1'-bis(diphenylphosphino)ferrocene (dppf), 1,1'-bis(diiso-
2
propylphosphino)ferrocene (dippf), 1,1'-bis(dicyclohexylphosphino)ferrocene (dcpf), 1,1'-
bis(ditert-butylphosphino)ferrocene (dtbpf), 1-diphenylphosphino-1'-ditert-
butylphosphinoferrocene (dppdtbpf) or 1,1ʹ-bis(5-methyl-2-furanylphosphino)ferrocene (dfurpf))
compounds were examined as catalysts for the intramolecular ring-closing hydroamination of 3-
(vinyloxy)propan-1-amine and the intermolecular hydroamination of phenylacetylene with a
variety of phenylamine reagents. The catalytic activity of the corresponding [Au2(µ-Cl)(µ-
PP)][BArF24] compounds that were generated in situ was also explored. Two new [Au
PP)] compounds with chiral bis(phosphino)ferrocene ligands (PP = 1,1'-bis(2R,5R-
2
Cl (µ-
2
dimethylphospholanyl)ferrocene (R-dMeplf) or 1,1'-bis(2S,5S-dimethylphospholanyl)ferrocene
(S-dMeplf)) were prepared, characterized spectroscopically and electrochemically, and evaluated
as catalysts in the ring-closing hydroamination reaction. In addition, the X-ray structures of
[Au
2
Cl
(µ-PP)] (PP = dppdtbpf, R-dMeplf and S-dMeplf) were determined.
2
Keywords: bis(phosphino)ferrocene; gold; hydroamination; catalysis; cyclic voltammetry; X-ray
crystal structure
1. Introduction
Bis(phosphino)ferrocene compounds with a variety of organic substituents, including
1,1ʹ-bis(diphenylphosphino)ferrocene (dppf), 1,1ʹ-bis(diiso-propylphosphino)ferrocene (dippf),
1,1ʹ- bis(dicyclohexylphosphino)ferrocene (dcpf), 1,1ʹ-bis(ditert- butylphosphino)ferrocene
(dtbpf), 1-(diphenylphosphino)-1ʹ-(ditert- butylphosphino)ferrocene (dppdtbpf) and 1,1′-
bis(bis(5-methyl-2-furanylphosphino))ferrocene (dfurpf) (Table 1), are commonly employed as
ligands [1–7]. These ligands typically coordinate to transition metals, most commonly group 10,

in a bidentate fashion [2,5,6,8]; however, other coordination modes are known. For example, late
transition metals, in particular gold, commonly exhibit monodentate coordination of these
ligands [9–12]. The coordination flexibility as well as the structural and electronic tunability of
bis(phosphino)ferrocene ligands make them particularly useful ligands in a variety of catalytic
applications.
Table 1
1,1′-bis(phosphino)ferrocene ligands.
R
Ph
iPr
Cy
tBu
Ph
Rʹ
Ph
Ligand
dppf
dippf
dcpf
dtbpf
iPr
Cy
tBu
tBu
dppdtbpf
dfurpf
5-methyl-2-furanyl 5-methyl-2-furanyl
Surprisingly, gold compounds with these bis(phosphino)ferrocene ligands have received
limited attention in catalysis. The ring closing reactions of (Z)-3-methylpent-2-en-4-yn-1-ol and
N-(prop-2-yn-1-yl)benzamide were catalyzed by [Au
2
(µ-Cl)(µ-PP)][BArF24] (PP = dppf, dippf,
Cl (µ-PP)]
dcpf, dtbpf, dppdtbpf or dfurpf) which was formed in situ by the reaction of the [Au
2
2
compounds with Na[BArF24] [12]. Although one of the poorer catalysts studied, [Au2Cl2(µ-
dppf)] was found to catalyze the reaction of phenylacetylene, pyridine hydrofluoride and 8-
methylquinoline N-oxide to yield fluoromethylphenyl ketone [13]. Finally, the Sonogashira
coupling reactions of terminal alkynes with aryl bromides and iodides was efficiently catalyzed
with gold(I) iodide and dppf [14]. Further examination of these compounds in catalytic
applications is clearly warranted.
One of the most common gold-catalyzed reactions is hydroamination, which has been
reviewed extensively in recent years [15–37]. Despite the fact that gold(III)-catalyzed
hydroamination of terminal alkynes had been known since 1987, it was not until 2003 that

Hayashi and Tanaka developed the first gold(I)-catalyzed intermolecular amination of alkynes
with anilines to form imines [38]. Gold(I) complexes selectively activate π-bonds of alkynes via
coordination of the alkyne forming a trans-alkenyl-gold complex intermediate, [LAu(η2-
ʹ)]+
RC≡CR , that withdraws electron density from the alkyne, making it susceptible to
nucleophilic attack [23]. Various types of ligands have been examined in these gold-catalyzed
reactions, but of greatest relevance to this work would be ligands containing a ferrocenyl group.
A gold(I) catalyst with a N-heterocyclic carbene (NHC) ligand containing a ferrocenyl group
was found to promote the intermolecular hydroamination of alkynes with anilines to form imines
[39]. While the yields of these reactions were generally good, a slight downward trend in product
yield was observed for more electron-rich aniline starting material. In a recent study, three
different ferrocenyl phosphonite ligands were examined in the gold catalyzed hydroamination of
terminal acetylenes [40]. The catalysts gave the desired imine products with a variety of
acetylene and amine starting materials.
This study aims to further examine gold compounds with bis(phosphino)ferrocene
ligands in catalysis. In particular, the goal was to determine the efficacy of the [Au
2Cl2
(µ-PP)]
and [Au
2
Cl(µ-Cl)(µ-PP)]+ complexes in both intra- and intermolecular hydroamination reactions.
In the course of this study, two new gold complexes with the chiral bis(phosphino)ferrocene
ligands 1,1ʹ-bis(2R,5R- dimethylphospholanyl)ferrocene (R-dMeplf) and 1,1ʹ-bis(2S,5S-
dimethylphospholanyl)ferrocene (S-dMeplf) were synthesized and characterized (Fig. 1). The X-
ray crystal structures of [Au2Cl2(dppdtbpf)], [Au2Cl2(R-dMeplf)] and [Au2Cl2(S-dMeplf)] were
determined.

Fig. 1. Structure of dMeplf ligands.
2. Results and discussion
The [Au2Cl2(µ-dMeplf)] compounds were synthesized using a procedure similar to those of
other [Au2Cl2(µ-bis(phosphino)ferrocene)] compounds. The compounds were characterized by
1H, 13C{1H} and 31P{1H} NMR spectroscopy. The stereocenters of the dMeplf ligands gave these
compounds complex 1H and 13C NMR patterns requiring the use of COSY, DEPT, HMBC and
HSQC experiments to assign all of the signals. The oxidative electrochemistry of the [Au2Cl2(µ-
dMeplf)] compounds was examined in CH2Cl2. Both compounds exhibit a single chemically and
electrochemically reversible wave (Fig. 2) whereas oxidation of the free dMeplf ligands under

3.50E-06
3.00E-06
2.50E-06
2.00E-06
1.50E-06
1.00E-06
5.00E-07
0.i0c0E+00
-5i.a00E-07
-1.00E-06
-1.50E-06
-2.00E-06
-2.50E-06
-3.00E-06
-3.50E-06
-4.00E-06
-4.50E-06
0.5 µA
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
Potential (V vs. FcH0/+)
Fig. 2. CV scan of 1.0 mM [Au2Cl2(µ-R-dMeplf)] in CH2Cl2 with 0.1 M [NBu4][PF6] as the
supporting electrolyte measured at 100 mV/s.
similar conditions gave a chemically reversible wave. With respect to the iron center in these
compounds, oxidation of the iron in both the free dMeplf ligands and the [Au2Cl2(µ- dMeplf)]
compounds occurs at potentials similar to dppdtbpf and dfurpf analogs (Table 2).
Table 2
CV data (E in V vs. FcH0/+) for ligands and [Au2Cl2(µ-PP)] compounds in CH2Cl2.
Free ligand [Au2Cl2(µ-PP)]
Reference
dppf
dippf
dcpf
dtbpf
dppdtbpf
dfurpf
R-dMeplf
S-dMeplf
0.23a
0.05a
0.02a
0.06
0.64
0.54
0.52
0.56
0.59
0.58
0.57
0.57
[41]
[42]
[43]
[44]
[41]
0.11a
0.15a
0.11a
0.11a
[12]
Free ligand [45]
Free ligand [45]
a Chemically reversible waves.

The X-ray crystal structures of [Au2Cl2(µ-dppdtbpf)] (Fig. 3), [Au2Cl2(µ-R-dMeplf)] and
Fig. 3. ORTEP drawing of [Au2Cl2(µ-dppdtbpf)]. Thermal ellipsoids are drawn at the 50%
probability level and the H atoms were omitted for clarity.
[Au2Cl2(µ-S-dMeplf)] (Fig. 4) were determined and were found to be similar to those of other
(a)
(b)
Fig. 4. ORTEP drawing of (a) [Au2Cl2(µ-R-dMeplf)] and (b) [Au2Cl2(µ-S-dMeplf)]. Thermal
ellipsoids are drawn at the 50% probability level and the H atoms were omitted for clarity.

gold compounds with 1,1'-bis(phosphino)ferrocene ligands. Selected bond lengths and angles are
presented (Table 3). These structures allow for calculation of the percent buried volume (%Vbur)
Table 3
Selected bond lengths (Å) and angles (°) for the structures of [Au2Cl2(µ-dppdtbpf)], [Au2Cl2(µ-
R-dMeplf)] and [Au2Cl2(µ-S-dMeplf)].
[Au2Cl2(µ-dppdtbpf)] [Au2Cl2(µ-R-dMeplf)] [Au2Cl2(µ-S-dMeplf)]
P1-Au1
P2-Au2
Au1-Cl1
Au2-Cl2
θa
XA-Fe-XB
P1-Au1-Cl1
P2-Au2-Cl2
2.2400(13)
2.2563(12)
2.2906(14)
2.3182(13)
3.74(15)
178.06(8)
176.24(4)
169.72(4)
2.2505(19)
2.248(2)
2.3218(19)
2.3163(19)
6.1(3)
174.12(16)
171.23(6)
171.10(6)
2.254(4)
2.253(4)
2.319(4)
2.329(4)
3.1(4)
177.9(2)
174.51(9)
165.41(8)
b
a The dihedral angle between the two C5 rings.
b X represents the centroid of the C5 rings.
[46] for the ligands (Table 4). For these gold compounds the phosphine substituted with tert-
butyl groups of dppdtbpf had a %Vbur that was 0.2% less than the dtbpf ligand. The phenyl-
substituted phosphine of dppdtbpf gave a %Vbur that was 2.2% larger than that of dppf,
potentially due to the proximity of the tert-butyl groups of the other phosphine. Somewhat
surprisingly, the dMeplf ligands had %Vbur values that differed by 1.5%. In the [PdCl2(κ2-dMeplf)]
compounds, the %Vbur values for the dMeplf ligands only differed by 0.1% [45]. A possible
explanation for the difference in the gold compounds with dMeplf ligands comes from the
aurophilic interactions [47,48] between the gold centers.
Table 4
The percent buried volume (%Vbur) and select measurement for [Au2Cl2(µ-PP)] (PP = 1,1ʹ-
bis(phosphino)ferrocene) compounds.
Compound
[Au2Cl2(µ-dppf)]
[Au2Cl2(µ-dtbpf)]
%Vbur
34.0
Au…Au (Å)
6.4589(2)b
8.1373(2)b
3.6073(14)b This work
7.2460(5)b
[10]
Ref.
[9]
[11]
τ(°)a
180.0(2)
-138.28(16)
41.6
41.4c
36.2d
38.8
153.9(2)
-142.4(2)
[Au2Cl2(µ-dppdtbpf)]
[Au2Cl2(µ-dippf)]

37.7
38.4f
36.9f
-68.7(3)
61.7(5)
-139.2(7)
3.60240(19)e
3.2441(4)e This work
3.064(3)b
This work
[12]
[Au2Cl2(µ-dfurpf)]
[Au2Cl2(µ-R-dMeplf)]
[Au2Cl2(µ-S-dMeplf)]
a Torsion angle CA-XA-XB-CB, with C being the carbon bound to phosphorus and X the centroid
of the C5 ring.
b Nearest intermolecular Au…Au distance.
c For -PtBu2 group.
d for -PPh2 group.
e Nearest intramolecular Au…Au distance.
f Average of two values.
In the R-dMeplf compound, there is a short intramolecular Au-Au interaction, similar to
that observed in the dfurpf analog [12]. The S-dMeplf compound displays an even shorter Au-Au
interaction, but in that case the interaction is intermolecular. This interaction creates a one-
dimensional polymer chain in the b-direction. The dMeplf ligands display helical chirality based
on the relative positions of the two phosphorous atoms as defined by the τ angles [49]. In these
gold compounds the R-dMeplf ligand adopts the P-1,2ʹ configuration whereas the S-dMeplf adopts
the M-1,4ʹ configuration. The P-1,2ʹ and M-1,4ʹ configurations are not helical enantiomers. From
the limited data available, this appears to be unusual for dMeplf ligands. The [PdCl2(dMeplf)]
compounds are enantiomers as the R-dMeplf compound adopts the P-1,2ʹ configuration having a τ
of 44.3° [45] while the S-dMeplf compound adopts the M-1,5ʹ configuration with a τ of -44.1°
[50]. Enantiomers were also observed in the [PtCl2(dMeplf)] compounds where R-dMeplf adopts
the P-1,2ʹ configuration (τ = 43.1°) and S-dMeplf adopts the M-1,5ʹ configuration (τ = -44.8°)
[45]. The reasons for the differences between the dMeplf ligands in the gold compounds in this
report are unclear.
A previous study examined the activity of [Au2Cl2(µ-PP)] compounds with
bis(phosphino)ferrocene ligands as catalysts in two different (Eq. (1 and 2)) ring-closing

(1)
(2)
reactions [12]. The addition of Na[BArF24] to these reactions leads to removal of a chloride
ligands from the gold compounds [11], which greatly enhanced their catalytic activity [12].
However some differences based on the steric and electronic properties of the
bis(phosphino)ferrocene ligands were noted. To further examine the catalytic properties of these
compounds, the intramolecular hydroamination of 3-(vinyloxy)propan-1-amine was carried out
using a series of [Au2Cl2(PP)] catalyst precursors (Eq. (3)). Previous studies have examined this
(3)
ring-closing using rhodium [51–53], palladium [51–54], platinum [51,53], copper [52], zinc
[52,55,56] and mercury [57] catalysts. The [Au2Cl2(µ-PP)] compounds in this study were all
determined to be poor catalysts in this ring-closing hydroamination. However, when one
equivalent of Na[BArF24] was added along with the gold precatalyst, the ring-closing was
determined to be quantitative (Table 5). Without the addition of the Na[BArF24] the reaction
mixtures maintained a yellow color during the course of the reaction, however with the addition
of the Na[BArF24] the solutions slowly turned orange-red over the course of the reaction.

Table 5
Yields for the catalytic ring-closing of 3-(vinyloxy)propan-1-amine using [Au2Cl2(µ-PP)]
catalysts in toluene-d8 at 115 °C for 4 h.
dppf dippf
<5% <5%
1 equiv. Na[BArF24] Quant. Quant. Quant. Quant.
dcpf dtbpf dppdtbpf R-dMeplf S-dMeplf
No Na[BArF24]
<5%
<5%
<5%
<5%
<5%
Quant.
Quant.
Quant.
The product of this ring-closing reaction, tetrahydro-2-methyl-1,3-oxazine, possesses a
chiral center, although due to the anomeric effect, there is a strong preference for the methyl
group to occupy an equatorial position while the N-H occupies an axial position [58]. The gold
complexes containing the chiral ligands R-dMeplf and S-dMeplf were effective catalysts for the
ring-closing hydroamination. Addition of 0.01 mol equivalents of the NMR shift reagent
tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)europium(III) hydrate to the
samples following the reaction resulted in identical downfield shifts for the proton signals of the
product regardless of which catalyst was used. Addition of an additional 0.01 equivalents of the
europium complex shifted the product signals further downfield. This suggests that the product
formed by both catalysts adopted the same regiochemistry.
To further investigate the catalytic activity of these compounds, the intermolecular
hydroamination reactions of phenylacetylene with a variety of aniline derivatives were examined
(Eq. (4)). Initial investigations were made using the conditions developed for the related gold
(4)
complex with a ferrocene-based ligand [39], however this gave limited formation of the desired
imine. Imine formation between aniline and phenylacetylene was maximized in toluene-d8 at 120
°C. Low (<5%) product formation was observed when the [Au
2
Cl (µ-PP)] compounds were used
2

as catalyst precursors. However, when a molar equivalent of Na[BArF24] was added to generate
the [Au (µ-Cl)(µ-PP)][BArF24] compounds in situ, the reaction mixture changed color from
2
yellow to dark orange over the course of the reactions and the desired imines were formed in
good to excellent yields (Table 6). Percent conversion to the imine products was quantified by
comparing the signal for the methyl group of the imine and the signal for the methoxy group
from anisole. For further verification of product formation, select reaction mixtures were
analyzed by GC-MS.
Table 6
Yields for the catalytic hydroamination of phenylacetylene with various aniline compounds
using in situ generated [Au2(µ-Cl)(µ-PP)][BArF24] catalysts in toluene-d8 at 120 °C for 6 h.
aniline
aniline without Na[BArF24]
Aniline
2,6-dimethylaniline
3,5-dimethylaniline
3,5-dimethylanilinea
2,4,6-trimethylaniline
2,6-diiso-propylaniline
4-fluoroaniline
dppf
<5%
35%
Quant.
20%
36%
90%
93%
53%
34%
43%
54%
32%
dippf
<5%
75%
93%
59%
53%
Quant.
79%
81%
12%
30%
76%
47%
dcpf
<5%
89%
Quant.
78%
58%
87%
59%
69%
25%
27%
55%
27%
dtbpf
<5%
91%
Quant.
81%
60%
92%
61%
73%
10%
16%
86%
37%
dppdtbpf dfurpf
<5%
62%
Quant.
55%
53%
Quant.
68%
74%
29%
56%
58%
46%
<5%
36%
Quant.
30%
24%
Quant.
92%
45%
46%
49%
38%
24%
2,6-difluoroaniline
3,5-difluoroaniline
4-trifluoromethylaniline
4-phenylaniline
a Reactions performed using microwave
There appears to be a combination of steric and electronic effects of the
bis(phosphino)ferrocene ligands that alters the catalytic efficiency of the [Au (µ-Cl)(µ-
2
PP)][BArF24] compounds. In general, higher yields seem to occur with more electron donating
bis(phosphino)ferrocene ligands and more electron rich aniline reagents. This differs from the
Au-NHC system in which the highest yield for hydroamination of phenylacetylene was observed
with aniline, with slightly lower yields found for p-tolylamine and mesitylamine [39]. With
electron donating substituents on the aniline starting materials, higher yields were observed with
disubstitution in the 2,6- positions as opposed to the 3,5- positions. However, bulkier groups in

the 2,6- positions did seem to slightly disfavor product formation. With electron withdrawing
substituents on the aniline starting materials, the opposite trend was noted; disubstitution in the
3,5- positions favored product formation over the 2,6- analog. Presumably, this reaction follows
a similar pathway to the previously proposed catalytic mechanism which includes a step in which
the coordinated alkyne undergoes nucleophilic attack by the aniline [59]. Thus, the more electron
rich anilines should be stronger nucleophiles and [Au
(µ-Cl)(µ-dppf)]+ should be the most
2
effective catalyst as dppf is both the least electron donating and least bulky ligand employed in
this study. Competitive formation of an inactive digold-σ,π-acetylide species has been observed
in a related catalytic system [60]. It is possible that a similar equilibrium occurs with [Au
2
(µ-
Cl)(µ-dppf)]+ reducing the conversion to product. Other [Au (µ-Cl)(µ-PP)]+ catalysts may not
2
form this additional species due to additional steric bulk preventing a second gold interaction
with the alkyne.
To further study the catalytic activity of these compounds the reaction of phenylacetylene
with 3,5-dimethylaniline was examined using a microwave reactor. The 3,5-dimethylaniline was
chosen as it gave modest yields using thermal conditions. The yields for the microwave heated
catalytic reactions were quite similar to those of the thermal reactions for all catalysts employed
in this study. The significantly shorter reaction times, 15 min as opposed to 6 hr, suggest that
further exploration of this method is warranted.
In summary, a series of [Au2Cl2(µ-PP)] compounds with bis(phosphino)ferrocene ligands
was explored as catalysts in an intramolecular hydroamination reaction and several closely
related intermolecular hydroamination reactions. The [Au2Cl2(µ-PP)] compounds were poor
catalysts in these reactions. However, removing a chloride ligand by adding one equivalent of
Na[BArF24] resulted in the formation of [Au2(µ-Cl)(µ-PP)][BArF24] and these compounds were

generally excellent catalysts in these reactions. For the intramolecular ring-closing
hydroamination reaction, varying the bis(phosphino)ferrocene ligand in the gold compounds had
no impact on the catalyst efficiency; all of the catalysts examined gave quantitative ring-closing.
For the intermolecular hydroamination reactions, both the bis(phosphino)ferrocene ligands and
the steric and electronic properties of the aniline nucleophile played a role in the catalysis.
3.
Experimental
3.1. General experimental methods
All reactions were performed under an argon atmosphere using standard Schlenk
techniques at 21 (± 1) ˚C unless otherwise noted. Toluene-d8, deuterochloroform, methanol and
chloroform were purchased from Fisher Scientific and used without further purification.
Purification of CH2Cl2 and Et2O which had been purchased from Fisher Scientific was carried
out using a method similar to one previously described [61]. Phenylacetylene, anisole, 2,2ʹ-
thiodiethanol and all aniline derivatives were purchased from Aldrich and used without further
purification. Tetrabutylammonium hexafluorophosphate ([NBu4][PF6]) was purchased from
Aldrich and prior to use was dried under vacuum at 100 ˚C. All bis(phosphino)ferrocene ligands,
ferrocene, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)europium(III) hydrate
and HAuCl4·H2O were purchased from Strem Chemicals and used without further purification.
The 3-(vinyloxy)propan-1-amine was purchased from Combi-Blocks and used without additional
purification. The gold compounds with bis(phosphino)ferrocene ligands (dppf [62], dippf [42],
dcpf [43], dtbpf [44], dppdtbpf [41] and dfurpf [12]), and Na[BArF24] (BArF24 = tetrakis-3,5-
bis(trifluoromethyl)phenylborate) [63] were prepared according to literature methods. In the
course of preparing the catalysts, single crystals of [Au2Cl2(dppdtbpf)] were prepared by vapor
diffusion of Et2O into a solution of the compound in CH2Cl2 at room temperature. NMR spectra

were obtained in toluene-d
using a Bruker Avance III HD 400 FT-NMR. The 1H and 13C{1H}
8
NMR spectra were referenced using internal TMS while the 31P{1H} NMR spectra were
referenced to external 85% H3PO4. GC-MS were performed using a VG/FISONS Model MD800
Gas Chromatograph/Mass Spectrometer. Microwave reactions were performed with a CEM 300
W Discover Explorer Hybrid. Elemental analysis was performed by Midwest Microlab.
3.2. Synthesis of [Au2Cl2(µ
-dMeplf)] compounds
A solution of HAuCl4·H2O (0.1812 g, 0.482 mmol) in a mixture of deionized water (1
mL) and methanol (5 mL) was prepared and stirred for 15 minutes at 0 °C. A solution of 2,2’-
thiodiethanol (0.0217 mL) in methanol (1 mL) was added dropwise to the HAuCl4·H2O solution,
and the mixture was stirred for 15 minutes at 0 °C. A solution of the desired dMeplf ligand (0.100
g, 0.241 mmol) was prepared in a mixture of chloroform (7.5 mL) and methanol (3 mL), and was
added to the HAuCl4·H2O solution. The reaction mixture was stirred for 18 hours, during which
time the solution was allowed to warm to room temperature and a yellow precipitate formed. It
was then washed with methanol (3x3 mL) and filtered. The remaining precipitate was dried in
vacuo, giving the product as a yellow solid (0.1066 g (50% yield) [Au2Cl2(µ-S-dMeplf)]; 0.1562 g
(74% yield) [Au2Cl2(µ-R-dMeplf)]). Single crystals of the [Au2Cl2(µ-dMeplf)] compounds were
grown by vapor diffusion of Et2O into a solution of the respective compound in CH2Cl2 at room
temperature.
3.2.1. Characterization of [Au2Cl2(µ
-S-dMeplf)]. 1H NMR δ (ppm): 0.87 (dd, 3H, J = 16
& 8 Hz, -CH3), 1.35 (m, 1H, CH2), 1.47 (m, 1H, CH2), 1.52 (dd, 3H, J = 20 & 8 Hz, -CH3), 2.11
(m, 1H, CH2), 2.41 (m, 2H, CH & CH2), 2.62 (m, 1H, CH), 4.24 (AA’XX’, 1H, -C5H4-Hα), 4.72
(AA’XX’, 1H, -C5H4-Hα), 4.82 (AA’XX’, 1H, -C5H4-Hβ), 4.86 (AA’XX’, 1H, C5H4-Hβ).
13C{1H} NMR δ (ppm): 13.5 (s, DEPT +, -CH3), 21.4 (d, J = 8.0 Hz, DEPT +, -CH3), 34.0 (d, J

= 1.0 Hz, DEPT -, -CH2), 34.2 (d, J = 4.0 Hz, DEPT -, -CH2), 34.2 (d, J = 40.0 Hz, DEPT +, -
CH), 36.7 (d, J = 36 Hz, DEPT +, -CH), 69.3 (d, J = 55.3 Hz, ipso-C5 ring, DEPT 0), 71.4 (d, J =
5.0 Hz, DEPT +, β-C5 ring), 74.1 (d, J = 7.0 Hz, DEPT +, β-C5 ring), 74.5 (d, J = 10.0 Hz, DEPT
+, α-C5), 77.1 (d, J = 18.1 Hz, DEPT +, α-C5). 31P{1H} NMR δ (ppm): 48.8 (s). Anal. Calcd. for
C22H32Au2Cl2FeP2: C, 30.06; H, 3.67. Found: C, 30.37; H, 3.83.
3.2.2. Characterization of [Au2Cl2(µ
-R-dMeplf)]. 1H NMR (CDCl3) δ (ppm): 0.87 (dd, 3H, J =
16 & 8 Hz, -CH3), 1.36 (m, 1H, CH2), 1.47 (m, 1H, CH2), 1.52 (dd, 3H, J = 20 & 8 Hz, -CH3),
2.10 (m, 1H, CH2), 2.39 (m, 2H, CH & CH2), 2.62 (m, 1H, CH), 4.24 (AA’XX’, 1H, -C5H4-Hα),
4.71 (AA’XX’, 1H, -C5H4-Hα), 4.81 (AA’XX’, 1H, -C5H4-Hβ), 4.85 (AA’XX’, 1H, -C5H4-Hβ).
13C{1H} NMR δ (ppm): 13.5 (s, DEPT +, -CH3), 21.4 (d, J = 5.0 Hz, DEPT +, -CH3), 34.0 (d, J
= 1.0 Hz, DEPT -, -CH2), 34.2 (d, J = 4.0 Hz, DEPT -, -CH2), 34.2 (d, J = 40.0 Hz, DEPT +, -
CH), 36.7 (d, J = 36 Hz, DEPT +, -CH), 69.3 (d, J = 62.4 Hz, ipso-C5 ring, DEPT 0), 71.4 (d, J =
4.0 Hz, DEPT +, β-C5 ring), 74.1 (d, J = 7.0 Hz, DEPT +, β-C5 ring), 74.5 (d, J = 10.0 Hz, DEPT
+, α-C5 ring), 77.1 (d, J = 15.1 Hz, DEPT +, α-C5 ring). 31P{1H} NMR δ (ppm): 48.8 (s). Anal.
Calcd. for C22H32Au2Cl2FeP2: C, 30.06; H, 3.67. Found: C, 30.33; H, 3.57.
3.3. Electrochemistry procedure. Cyclic voltammetry experiments were conducted using a
CH Instruments Model CHI260D potentiostat at room temperature (21 ± 1 °C) under an argon
atmosphere. Analyte concentrations of 1.0 mM in CH2Cl2 (10.0 mL) using 0.1 M [NBu4][PF6] as
the supporting electrolyte were used in all experiments. The working electrode was a glassy
carbon disk (1.0 mm diameter) that had been polished with 1.0 µm then 0.25 µm diamond paste
and rinsed with methylene chloride prior to use. A platinum wire counter electrode and a
nonaqueous Ag/AgCl pseudo-reference electrode that was separated from the solution by a frit
were employed in all experiments. Ferrocene was added at the end of the experiments for use as

an internal reference. Background scans were subtracted from all data. Experiments were
conducted at scan rates of 100–1000 mV s−1 in 100 mV s−1 increments. All data are reported at a
scan rate of 100 mV s−1.
3.4. X-ray diffraction studies
Single crystals of [Au2Cl2(µ-dppdtbpf)], [Au2Cl2(µ-R-dMeplf)] and [Au2Cl2(µ-S-dMeplf)]
were selected for analysis on a Bruker-AXS SMART Apex II X-ray diffractometer using Mo Kα
radiation with a graphite monochromater [64]. All samples were mounted using a MiTeGen
MicroMount and NVH oil. Data were collected and are reported in Table 7. Unit cells were
determined by taking 12 data frames, 0.5° ϕ, in three sections of the Ewald sphere. Full
hemispheres were collected on each crystal and integrated using SAINT Plus [65]. Data were
corrected for absorption correction using SADABS [66]. Structures were solved by the use of
intrinsic phasing [67]. Least squares refinement on F2 was used for all reflections [68].
Straightforward structure solution, refinement, and the calculations of measurements were
accomplished with the APEX3 package [69]. Non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were placed in idealized, theoretical positions. The structure of [Au2Cl2(µ-
dppdtbpf)] was solved in a centrosymmetric space group. The structures of [Au2Cl2(µ-R-dMeplf)]
and [Au2Cl2(µ-S-dMeplf)] were solved in the non-centrosymmetric space group, P212121, and
refined as an inversion twin using the TWIN and BASF commands; the Flack parameter
indicated the crystals were a single enantiomer. The residual electron density for [Au2Cl2(µ-S-
dMeplf)] was higher than expected at 2.52 eÅ-3. The elemental analysis concluded that Au was
properly assigned and the residual was attributed to a heavy atom absorption correction problem
with Au that could not be corrected with additional face indexing. Reported measurements were
made using OLEX2 [70]. The %Vbur calculations were performed using SambVca 2.1 [71].

Table 7
Crystal data and structure analysis results.
[Au2Cl2(µ-dppdtbpf)] [Au2Cl2(µ-R-dMeplf)] [Au2Cl2(µ-S-dMeplf)]
formula
fw
C30H36Au2Cl2FeP2
979.22
C22H32Au2Cl2FeP2
879.10
C22H32Au2Cl2FeP2
879.10
crystal system
space group
a, Å
b, Å
c, Å
monoclinic
P21/n
9.620(5)
17.309(8)
18.369(9)
90
98.749(16)
90
3023(3)
4
Orthorhombic
P212121
10.583(6)
14.809(8)
16.287(9)
90
90
90
2553(2)
4
orthorhombic
P212121
11.396(18)
14.19(2)
16.08(3)
90
90
90
2600(7)
4
α
β
, deg
, deg
γ
, deg
V, Å3
Z
cryst. size, mm
cryst. color
radiation
temp, K
0.317 x 0.177 x 0.164 0.341 x 0.202 x 0.195 0.300 x 0.135 x 0.052
orange
Orange
0.71073
100(2)
orange
0.71073
100(2)
0.71073
100(2)
3.24-57.66
3.72-57.6
3.82-57.6
2θ range, deg
data collected
h
k
l
-12 to 12
-23 to 22
-23 to 23
-13 to 14
-19 to 19
-22 to 21
30548
-15 to 15
-19 to 18
-21 to 21
31179
no. of data collected 35893
no. of unique data
abs. corr
7446
SADABS
6259
SADABS
6368
SADABS
final R indices
R1
wR2
0.0318
0.0486
1.046
0.0273
0.0419
0.879
0.0392
0.0579
0.966
goodness of fit
3.5. Catalytic Studies
3.5.1. Ring-closing hydroamination. In an argon filled glovebox, either the desired
PP)] [Au2Cl2(µ-PP)] compound (0.005 mmol) and
[Au2Cl2(µ-
compound (0.005 mmol) or the desired
Na[BArF ] (0.005 mmol)
were added to a J Young NMR tube. Toluene-d8 (0.75 mL) and 3-
24
vinyloxy-1-propamine (0.100 mol) were added to the J Young NMR tube. The tube was sealed,
removed from the glove box, placed in an aluminum block and heated to 115 °C for 4 hours.
After heating the tube was removed from the heating block and allowed to cool to room

temperature before 1H and 13C{1H} NMR spectra were obtained. Representative 1H and 13C{1H}
NMR spectra of the starting material and the reaction mixture are available in the supporting
information.
3.5.2. Hydroamination of phenylacetylene.
3.5.1.1. Thermal conditions. The hydroamination reactions using were carried out in J Young
an atmosphere of argon. In an argon filled glovebox, either [Au2Cl2(µ-PP)]
NMR tubes under
(0.010 mmol) or [Au2Cl2(µ-PP)] (0.010 mmol) and Na[BArF24] (0.010 mmol) were dissolved in
1 mL toluene-d8. Anisole (50 µL) was added as an internal standard. The organic reagents,
phenylacetylene (0.110 mL, 1 mmol) and the desired aniline (~0.100 mL, 1.1 mmol) were then
added. The tube was closed and the reactants thoroughly mixed before being inserted into an
aluminum heating block and heated at 120 °C for 6 h. Upon cooling to room temperature, 1H and
13C{1H} NMR spectra of the reaction mixtures were obtained. Representative 1H and 13C{1H}
NMR spectra of the starting materials, internal standard and the reaction mixtures along with a
GC-MS trace of a reaction mixture are available in the supporting information.
3.5.1.1. Microwave conditions. A microwave tube was prepared with [Au2Cl2(µ-PP)] (0.02
mmol) and Na[BArF24] (0.0176 g, 0.02 mmol) along with a stir bar. In a glove box, under an
atmosphere of argon, the solids were dissolved in 2 mL toluene-d8. Anisole (100 µL) was added
as an internal standard. Phenylacetylene (0.220 mL, 2 mmol) and 3,5-dimethylaniline (~0.27 mL,
2.2 mmol) were then added. The tube was then sealed and placed in the microwave reactor at
160 °C for 15 minutes. Upon cooling to room temperature, the reaction vessel was brought into
the glovebox and a sample of the solution was transferred to an NMR tube. The 1H and 13C{1H}
NMR spectra of the reaction mixture was obtained.
Acknowledgements

This work was partially funded by the National Science Foundation (CHE 1565648). C. N., N. E.
M., S. A. W. and R. K. G. thank the Academic Research Committee at Lafayette College for
their support through the EXCEL Scholars program. The X-ray facility at the College of New
Jersey was funded by the National Science Foundation (MRI 0922931).
Appendix A. Supplementary data
Electronic Supplementary Information (ESI) available: NMR spectra for [Au2Cl2(µ-R-
dMeplf)], [Au2Cl2(µ-S-dMeplf)] and representatives of all catalytic reactions, representative
GC-MS trace for intermolecular hydroamination reaction and results of %Vbur calculations
from SambVca 2.1. CCDC 1953994 for [Au2Cl2(µ-S-dMeplf)], 1953995 for [Au2Cl2(µ-R-
dMeplf)] and 1953996 for [Au2Cl2(
found online at https://doi.org/.
References
µ-dppdtbpf)]. Supplementary data to this article can be
[1]
T. Hayashi, Asymmetric catalysis with chiral ferrocenylphosphine ligands, in: A. Togni,
T.S.A. Hor (Eds.), Ferrocenes: Homogeneous Catalysis, Organic Synthesis, Materials
Science, VCH, Weinheim, Germany, 1995: pp. 105–142.
[2]
[3]
T.J. Colacot, S. Parisel, Synthesis, Coordination chemistry and catalytic use of dppf
Analogs, in: Ferrocenes: Ligands, Materials and Biomolecules, 2008: pp 117-140.
P. Štěpnička, 1ʹ-Functionalised ferrocene phosphines: Synthesis, coordination chemistry
and catalytic applicaitons, in: P. Štěpnička (Ed.), Ferrocenes: Ligands, Materials and
Biomolecules, John Wiley & Sons, Inc., West Sussex, England, 2008: pp. 177–204.
H.-U. Blaser, W. Chen, F. Camponovo, A. Togni, Chiral 1,2-disubstituted ferrocene
diphosphines for asymmetric catalysis, in: P. Štěpnička (Ed.), Ferrocenes: Ligands,
Materials and Biomolecules, John Wiley & Sons, Inc., West Sussex, England, 2008: pp.
205–236.
K.-S. Gan, T.S.A. Hor, 1,1ʹ-Bis(diphenylphosphino)ferrocene - Coordination chemistry,
organic synthesis and catalysis, in: A. Togni, T. Hayashi (Eds.), Ferrocenes:
Homogeneous Catalysis, Organic Synthesis, Materials Science, VCH, Weinheim,
Germany, 1995: pp. 3–104.
S.W. Chien, T.S.A. Hor, The coordination and homogeneous catalytic chemistry of 1,1ʹ-
bis(diphenylphosphino)ferrocene and its chalcogenide derivatives, in: P. Štěpnička (Ed.),
Ferrocenes: Ligands, Materials and Biomolecules, John Wiley & Sons, Inc., West Sussex,
England, 2008: pp. 33-116.
P. Štěpnička, M. Lamač, Synthesis and catalytic use of planar chiral and polydentate
ferrocene donors, in: P. Štěpnička (Ed.), in: P. Štěpnička (Ed.), Ferrocenes: Ligands,
[4]
[5]
[6]
[7]

Materials and Biomolecules, John Wiley & Sons, Inc., West Sussex, England, 2008: pp.
237–378.
[8]
[9]
K.M. Gramigna, J. V. Oria, C.L. Mandell, M.A. Tiedemann, W.G. Dougherty, N.A. Piro,
W.S. Kassel, B.C. Chan, P.L. Diaconescu, C. Nataro, Organometallics. 32 (2013) 5966–
5979.
E.C. Constable, C.E. Housecroft, M. Neuburger, S. Schaffner, E. Shardlow, Acta
Crystallogr., Sect. E Struct. Rep. Online. E63 (2007) m1697.
[10] T. V. Segapelo, I.A. Guzei, J. Darkwa, J. Organomet. Chem. 693 (2008) 701–708.
[11] S.F. Hartlaub, N.K. Lauricella, C.N. Ryczek, A.G. Furneaux, J.D. Melton, N.A. Piro, W.S.
Kassel, C. Nataro, Eur. J. Inorg. Chem. 2017 (2017) 424–432.
[12] T.A. Michaels, O.F. Pritchard, J.S. Dell, M.W. Bezpalko, W.S. Kassel, C. Nataro, J.
Organomet. Chem. 889 (2019) 1–8.
[13] X. Zeng, S. Liu, Z. Shi, G. Liu, B. Xu, Angew. Chem., Int. Ed. 55 (2016) 10032–10036.
[14] P. Li, L. Wang, M. Wang, F. You, Eur. J. Org. Chem. (2008) 5946–5951.
[15] R.A. Widenhoefer, X. Han, Eur. J. Org. Chem. (2006) 4555–4563.
[16] R.A. Widenhoefer, Chem. Eur. J. 14 (2008) 5382–5391.
[17] E. Genin, V. Michelet, PATAI’S Chem. Funct. Groups. (2014) 1–60.
[18] R.J. Lungren, E-ROS. (2014) 1–2.
[19] H. Ohno, H. Chiba, S. Inuki, S. Oishi, N. Fujii, Synlett. 25 (2014) 179–192.
[20] Y.-M. Wang, A.D. Lackner, F.D. Toste, Acc. Chem. Res. 47 (2014) 889–901.
[21] W. Yang, A.S.K. Hashmi, Chem. Soc. Rev. 43 (2014) 2941–2955.
[22] M.J. Coghlan, E-ROS. (2015) 1–24.
[23] R. Dorel, A.M. Echavarren, Chem. Rev. 115 (2015) 9028–9072.
[24] V. Michelet, Top Curr. Chem. 357 (2015) 95–132.
[25] A. Arcadi, Top. Heterocycl. Chem. 46 (2016) 53–85.
[26] D.H. Miles, F.D. Toste, Top. Heterocycl. Chem. 46 (2016) 227–248.
[27] A.S.K. Hashmi, A critical comparison: Copper, silver and gold, in: M. Harmata (Ed.),
Silver in Organic Chemistry, John Wiley & Sons, Inc., New York, NY, 2010: pp. 357–
379.
[28] R.S. Ramon, S.P. Nolan, E-ROS. (2016) 1–7.
[29] C. Michon, M.-A. Abadie, F. Medina, F. Agbossou-Niedercorn, J. Organomet. Chem. 847
(2017) 13–27.
[30] S.A. Shahzada, M.A. Sajid, Z.A. Khan, D. Canseco-Gonzalezb, Synth. Commun. 47
(2017) 735–755.
[31] A.S.K. Hashmi, M. Buehrle, Aldrichimica Acta. 43 (2010) 27–33.
[32] A.S.K. Hashmi, C. Hubbert, Angew. Chem., Int. Ed. 49 (2010) 1010–1012.
[33] J.G. De Vries, N. Mršić, Catal. Sci. Technol. 1 (2011) 727–735.
[34] K. Hemming, Annu. Rep. Prog. Chem., Sect. B. 107 (2011) 118–137.
[35] I. Krossing, Angew. Chem., Int. Ed. 50 (2011) 11576–11578.
[36] Z. Li, D.A. Capretto, C. He, Gold-catalyzed additions to alkenes: N-nucleophiles, in: S.K.
Hashmi, F.D. Toste (Eds.), Modern Gold Catalyzed Synthesis, 1st ed., Wiley-VCH,
Verlag, 2012: pp. 297–302.
[37] M. Chiarucci, M. Bandini, Beilstein J. Org. Chem. 9 (2013) 2586–2614.
[38] E. Mizushima, T. Hayashi, M. Tanaka, Org. Lett. 5 (2003) 3349–3352.
[39] S. Ibáñez, M. Poyatos, L.N. Dawe, D. Gusev, E. Peris, Organometallics. 35 (2016) 2747–
2758.

[40] E. Deck, H.E. Wagner, J. Paradies, F. Breher, Chem. Commun. 55 (2019) 5323–5326.
[41] S.L. Kahn, M.K. Breheney, S.L. Martinak, S.M. Fosbenner, A.R. Seibert, W.S. Kassel,
W.G. Dougherty, C. Nataro, Organometallics. 28 (2009) 2119–2126.
[42] J.H.L. Ong, C. Nataro, J.A. Golen, A.L. Rheingold, Organometallics. 22 (2003) 5027–
5032.
[43] L.E. Hagopian, A.N. Campbell, J.A. Golen, A.L. Rheingold, C. Nataro, J. Organomet.
Chem. 691 (2006) 4890–4900.
[44] F.N. Blanco, L.E. Hagopian, W.R. McNamara, J.A. Golen, A.L. Rheingold, C. Nataro,
Organometallics. 25 (2006) 4292–4300.
[45] C.L. Mandell, S.S. Kleinbach, W.G. Dougherty, W.S. Kassel, C. Nataro, Inorg. Chem. 49
(2010) 9718–9727.
[46] H. Clavier, S.P. Nolan, Chem. Commun. 46 (2010) 841–861.
[47] H. Schmidbaur, A. Schier, Chem. Soc. Rev. 41 (2012) 370–412.
[48] D. Weber, M.R. Gagne, Top. Curr. Chem. 357 (2015) 167–212.
[49] S.I. Kirin, H.B. Kraatz, N. Metzler-Nolte, Chem. Soc. Rev. 35 (2006) 348–354.
[50] T.J. Brunker, N.F. Blank, J.R. Moncarz, C. Scriban, B.J. Anderson, D.S. Glueck, L.N.
Zakharov, J.A. Golen, R.D. Sommer, C.D. Incarvito, A.L. Rheingold, Organometallics. 24
(2005) 2730–2746.
[51] P.G. Hayes, S.A.M. Stringer, C.M. Vogels, S.A. Westcott, Transit. Met. Chem. 26 (2001)
261–266.
[52] R.Q. Su, T.E. Müller, Tetrahedron. 57 (2001) 6027–6033.
[53] C.M. Vogels, P.G. Hayes, M.P. Shaver, S.A. Westcott, Chem. Commun. (2000) 51–52.
[54] M. Tada, M. Shimamoto, T. Sasaki, Y. Iwasawa, Chem. Commun. 10 (2004) 2562–2563.
[55] V. Neff, T.E. Müller, J.A. Lercher, Chem. Commun. 2 (2002) 906–907.
[56] J. Penzien, C. Haeßner, A. Jentys, K. Köhler, T.E. Müller, J.A. Lercher, J. Catal. 221
(2004) 302–312.
[57] B.F. Kukharev, V.K. Stankevich, G.R. Klimenko, V.A. Kukhareva, Russ. J. Org. Chem.
43 (2007) 966–969.
[58] H. Booth, R.U. Lemieux, Can. J. Chem. 49 (1971) 777–788.
[59] A. Zhdanko, M.E. Maier, Angew. Chem., Int. Ed. 53 (2014) 7760–7764.
[60] N. Huguet, D. Lebœuf, A.M. Echavarren, Chem. Eur. J. 19 (2013) 6581–6585.
[61] A.B. Pangborn, M.A. Giardello, R.H. Grubbs, R.K. Rosen, F.J. Timmers,
Organometallics. 15 (1996) 1518–1520.
[62] D.T. Hill, G.R. Girard, F.L. McCabe, R.K. Johnson, P.D. Stupik, J.H. Zhang, W.M. Reiff,
D.S. Eggleston, Inorg. Chem. 28 (1989) 3529–3533.
[63] N.A. Yakelis, R.G. Bergman, Organometallics. 24 (2005) 3579.
[64] Bruker Instrument Service version 2015.5.1.3. Bruker AXS Inc., Madison, Wisconsin,
USA, 2015.
[65] SAINT Plus, Data Reduction Software, Version 8.35A. Bruker AXS Inc., Madison,
Wisconsin, USA, 2015.
[66] SADABS, version 2014/5, Bruker AXS Inc. Madison, Wisconsin, USA, 2015.
[67] G.M. Sheldrick, Acta Crystallogr., Sect. A Found. Adv. 71 (2015) 3–8.
[68] G.M. Sheldrick, Acta Crystallogr., Sect. C Cryst. Struct. Commun. 71 (2015) 3–8.
[69] APEX3, Data Refinement Software, version 2015.9-0, Bruker AXS Inc., Madison,
Wisconsin, USA, 2015.
[70] O. V. Dolomanov, L.J. Bourhis, R.J. Gildea, J.A.K. Howard, H. Puschmann, J. Appl.

Cryst. 42 (2009) 339–341.
[71] L. Falivene, Z. Cao, A. Petta, L. Serra, A. Poater, R. Oliva, V. Scarano, L. Cavallo, Nature
Chem. 11 (2019) 872-879.

Highlights
•
•
•
Activation of [Au2Cl2(PP)] (PP = bis(phosphino)ferrocene) by Na[B(3,5-C6H3(CF3)2)4]-
[Au2(µ-Cl)(PP)][B(3,5-C6H3(CF3)2)4] catalysis of several hydroamination reactions
[Au2Cl2(dppdtbpf)] and [Au2Cl2(dMeplf)] (Mepl = R or S-2,5-dimethylphosphalano)
structures
•
Electrochemistry of [Au2Cl2(PP)] compounds

Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships
that could have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered
as potential competing interests: