(2-Pyridyloxy)arsines as ligands in transition metal chemistry: a stepwise As(iii) → As(ii) → As(i) reduction

Article abstract of DOI:10.1039/d0dt01538e

Neutral inherently tri- and tetradentate ligands of the type Ph3-xAs(PyO)x (x = 2 (1), 3 (2)) have been synthesized and characterized. Reaction of 1 with [RuCl2(PPh3)3] affords complex [PhAs(μ-PyO)2RuCl2(PPh3)] (3), whereas 2 and [RuCl2(PPh3)3] react with formation of [As(μ-PyO)2RuCl(PPh3)2] (5) and [Ph3P(PyO)]Cl (6). Treatment of complex 5 with [AuCl(tht)] (tht = tetrahydrothiophene) results in liberation of tht and formation of [AuCl(As(PyO)2)RuCl(PPh3)2] (7), featuring an (Au-As-Ru) core. For compounds 3, 5, and 7 the As-Ru and As-Au bond situation has been investigated using NBO, AIM and ELF analysis, allowing the assignment of pronounced canonical forms of σ-(AsIII→RuII) to 3, σ-(AsII-RuI) to 5 and σ-(AuI←AsI→RuII) to 7. This journal is

Full text of DOI:10.1039/d0dt01538e

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DOI: 10.1039/D0DT01538E
ARTICLE
(2-Pyridyloxy)arsines as Ligands in Transition Metal
Chemistry: A Stepwise As(III)→As(II)→As(I) Reduction
Received 00th January 20xx,
Accepted 00th January 20xx
Robert Gericke*a and Jörg Wagler*a
DOI: 10.1039/x0xx00000x
Neutral inherently tri- and tetradentate ligands of the type Ph3-xAs(PyO)x (x = 2 (1), 3 (2)) have been synthesized and
characterized. Reaction of
1 with [RuCl2(PPh3)3] affords complex [PhAs(µ-PyO)2RuCl2(PPh3)] (3), whereas 2 and
[RuCl2(PPh3)3] react with formation of [As(µ-PyO)2RuCl(PPh3)2] (5) and [Ph3P(PyO)]Cl (6). Treatment of complex 5 with
[AuCl(tht)] (tht = tetrahydrothiophene) results in liberation of tht and formation of [AuCl(As(PyO)2)Ru(PPh3)2] (7), featuring
an (Au-As-Ru) core. For compounds 3, 5, and 7 the As-Ru and As-Au bond situation has been investigated using NBO, AIM
and ELF analysis, allowing the assignment of pronounced canonical forms of σ-(AsIII→RuII) to 3, σ-(AsII–RuI) to 5 and σ-
(AuI←AsI→RuII) to 7.
Interestingly, Thomas et al. performed NBO (Natural Bond
Orbital) analyses on the As-Co-complex C (Chart 1), which revealed
an almost equal contribution of both atoms to the -(AsCo) bond
Introduction
Exploration of synthesis routes toward hetero-bi/trimetallic
complexes featuring an ETM bond or TMETM motif (E: heavier
main group metal/metalloid; TM: transition metal) are of current
interest in coordination chemistry, with motivation arising from
applications of ETM complexes as anion sensors, their potential
general catalytic activity, starting material for chemical vapour
deposition or even their capability of small molecule activation.1
Oxidation states of transition metal bound group 15 elements often
range from +III to +V.2 N-Heterocyclic arsenium and stibenium
cations as ligands at Pt(0) (A, Chart 1)3 and Co(-1) (B)4 have been
investigated. In the resultant hetero-bimetallic complexes a non-
coordinating electron pair remains at the pnictogen element.
with a slight polarization towards arsenic (As: 54.8%, Co: 45.2%) and
a lone pair with high s-contribution at the As center.5 Ragogna et al.
extended their principle of triphosphenium cation6 towards arsenic
in order to stabilize an As(I) species with a bis(phosphine)borate
ligand. The resulting compound proved suitable as a -donor
towards group 6 carbonyls (e.g., compound D).1d Dostál et al.
demonstrated that NCN pincer ligands are capable of stabilizing
low-valent As(I) and Sb(I), which were also able to coordinate to
late transition metals (Au, Pt) with formation of compounds such as
E.7
To the best of our knowledge, mixed TM hetero-trinuclear
complexes featuring arsenic are scarce. Ebsworth et al. presented a
synthetic study to form a trimetallic Ir–As–Ru complex (F) by
oxidative addition of AsH3 to [Ir(CO)Cl(PEt3)2] followed by reaction
with [RuCl2(cymene)]2.8 Herein we present a route to stepwise
Pt(PPh3)2
OC CO
Ph2P Co PPh2
As
Co(CO)4
As
O
O
N
N
As
forming
a trinuclear complex which features a (hitherto
Mes
Mes
N
N
N
N
unprecedented) Au–As–Ru core. Interestingly, along the synthesis
route the As(I) ligand forms from a simple As(III) precursor without
the aid of N-heterocyclic or bis(phosphine)borate stabilization or
NCN-pincer ligands.
S
S
A
B
C
AuCl
As
Cr(CO)5
H
H
tBu
tBu
Et3P
N
N
As
As
Ph2P
Ph
PPh2
Cl
Ir
Ru
H
OC
Cl
Results and discussion
Cl
B
PEt3
Ph
Compounds of type Ph3-xAs(PyO)x
D
E
F
Inspired by the syntheses of the phosphorus compounds PhP(PyO)2
and P(PyO)3 (PyO = 2-pyridyloxy),9 we obtained the corresponding
tri- and tetradentate arsenic ligands from reactions of
dichlorophenylarsane or arsenic(III) chloride, respectively, with 2-
hydroxypyridine (PyOH) in the presence of triethylamine (Et3N) as
supporting base (Scheme 1).
Chart 1. Examples of As-TM-complexes.
a. Institut für Anorganische Chemie, Technische Universität Bergakademie Freiberg,
Leipziger Straße 29, D-09596 Freiberg, Germany.
† Footnotes relating to the title and/or authors should appear here.
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
+ x Et3N
- x Et3NHCl
1
2
x = 2:
x = 3:
Ph3-xAsClx
+ x
Ph3-xAs
O
N
N
O
x
H
Scheme 1. Synthesis of 2-pyridyloxyarsine ligands 1 and 2.
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compounds 1 and 2 with single-crystal X-ray diffraction (Figure 2)
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Both compounds were isolated as colorless and highly hygroscopic revealed the exclusive presence of the As-O bonding motifs (with
DOI: 10.1039/D0DT01538E
solids. Even though elemental analyses confirmed purity of the weak As···N coordination trans to the As-O bonds) for both 1 and 2
products, for compound 1 three sets of PyO related 1H NMR signals in the solid state. The coordination spheres about the arsenic atoms
were observed in an approximate 1:1:1 ratio (Figure 1). The are trigonal pyramidal, with O-As-O angles close to 90° and, in 1, O-
corresponding signals for two different phenyl groups appear in an As-C bond angles close to 100°. The molecules exhibit the same
approximate 1:2 ratio in the 1H NMR spectrum. Hence, there are conformations as their lighter phosphorus relatives. Compound 1
two different isomers in an approximate 1:2 ratio present in CDCl3 exhibits a larger deviation between the As1···N1 (2.691(1) Å) and
solution, a major isomer with two different As-PyO bonding motifs As1···N2 (2.738(2) Å) separation by approximately 0.05 Å, whereas
and a minor isomer with chemically equivalent PyO moieties.
in compound 2 the As···N separations are within a very narrow
range (2.68-2.69 Å).
Figure 1. Comparison of the 1H NMR spectra of compound
PhP(PyO)2 (top) and PhAs(PyO)2 (1, bottom) in CDCl3 solution. Three
sets of pyridyloxy related signals in 1 are indicated in black, purple
and orange.
Figure 2. Molecular structures of 1 (left) and 2 (right). Ellipsoids are
shown at 50% probability level. Hydrogen atoms have been omitted
for clarity. Selected interatomic separations (Å) and angles (deg): 1:
As1-O1 1.843(1), As1-O2 1.839(1), As1-C11 1.943(2), O1-C1
1.349(2), O2-C6 1.348(2), N1-C1 1.324(2), N2-C6 1.323(2), O1-As1-
O2 82.78(5), O1-As1-C11 97.26(6), O2-As1-C11 98.60(6), O1-C1-N1
116.24(15), O2-C6-N2 116.99(15); 2: As1-O1 1.810(3), As1-O2
1.828(3), As1-O3 1.827(3), O1-C1 1.352(6), O2-C6 1.353(6), O3-C11
1.391(8), N1-C1 1.305(6), N2-C6 1.322(5), N3-C11 1.314(5), O1-As1-
O2 92.6(1), O1-As1-O3 89.6(2), O2-As1-O3 89.5(2), O1-C1-N1
117.3(4), O2-C6-N2 115.7(4), O3-C11-N3 111.0(8).
According to quantum chemical calculations, out of the symmetric
isomers 1I is thermodynamically more stable than 1III by
approximately 3.31 kcal mol-1, while the isomer 1II with two
different PyO moieties (As-O and As-N bound) is marginally more
stable than 1I (-0.07 kcal mol-1, Chart 2). Therefore, we assign the
signals to the isomers 1I (minor) and 1II (major component).
O
N
N
In order to shed some light into the discrepancy between the
observation of As-N and As-O bonding motifs in solution and only
As-O bonding in solid state, relaxed energy surface scans at DFT
level of theory were performed. The relaxed energy scans were
started from the gas phase optimized structure of isomer 1I and 1II
(see supporting information for details, Figure S17-S20). The
transition state of an isomerization was calculated and compared
with its lighter phosphorus analogue where exclusive P-O bonding
was observed. The ΔG‡ (Gibbs free energy of the transition state,
Figure S21) of an isomerization of 1II into 1I was found to be
significantly smaller for compound 1 (23.4 kcal mol-1) in comparison
to its phosphorus analogues (33.8 kcal mol-1). This trend is in accord
with the observation by Garje and Jain, who, for related
pentavalent group 15 compounds, reported a tendency for chelate
formation at the heavier congener (Sb vs. As).10 Further analyses
(B3LYP cc-pVTZ/SDD(As)-D3(BJ): 16.4 (gas phase), 17.6 kcal mol-1
(COSMO(CHCl3)); Figure S22) confirmed that the activation barrier
could be well below 20 kcal mol-1, thus speaking for possible
dynamic isomerization at room temperature.
N
O
O
As
N
As
O
As
N
O
N
O
1I
1II
1III
O
O
N
N
N
N
N
O
O
O
O
O
As
As
As
O
As
N
O
N
N
O
N
O
N
N
N
O
2I
2II
2III
2IV
Chart 2. Isomers of compounds 1 and 2.
The assignment of signals of the minor isomer (set 1) to 1I is
furthermore supported by comparison with spectra of the
corresponding phosphorus compound PhP(PyO)2, the 1H and 13C
NMR signals of which show only small deviations (merely a slight
systematic high field shift of 1H signals of 1I). Set 2 exhibits the
second lowest deviation and can be assigned to the As-O bonded
PyO unit in isomer 1II. Set 3 exhibits the largest deviations and can
be assigned to the As-N bonded PyO unit in 1II.
For compound 2 only one set of broad signals was detected in
both the 1H and 13C NMR spectrum. Quantum chemical calculations
revealed that there are only small energy differences between the
four isomers 2I (0.44), 2II (0.00), 2III (3.56) and 2IV (3.27 kcal mol-1),
whereby isomer 2III and 2IV with two or three AsN bonds are the
least favored ones. Determination of the molecular structures of
Reactivity of Ph3-xAs(PyO)x toward [RuCl2(PPh3)3]
Reaction of 1 with [RuCl2(PPh3)3] in chloroform results in the
formation of the all-cis complex [PhAs(µ-PyO)2RuCl2(PPh3)] (3) with
liberation of two equivalents of triphenylphosphine, the release of
which was confirmed by 31P NMR spectroscopy (Scheme 2). Ligand
1 coordinates to ruthenium in a fac fashion, which leads to a cis-
coordination of the chlorine atoms. Formation of the related
phosphorus complex [PhP(µ-PyO)2RuCl2(PPh3)] under similar
reaction conditions has been reported.9 However, compound 1 was
2 | J. Name., 2012, 00, 1-3
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observed to appear in two isomers in an approximate ratio of 1:2 compounds 5 and 6 as final products (Scheme 2).ViPewroAortficloe fOntlhinee
for 1I:1II. In order to obtain compound 3 (exclusive As-O bonding formation of compound 6 was established by its deliberate
DOI: 10.1039/D0DT01538E
mode) in 53% isolated yield, an isomerization of 1II into 1I is synthesis in the reaction of PPh3 with PyOH and CCl4 in acetonitrile.
required (vide supra). Reaction of 1 with [RuCl2(PPh3)3] is therefore As already reported by Appel et al. for similar reactions, [Ph3P-
in accord with a dynamic interconversion of 1II and 1I.
CH2Cl]Cl could be identified as by-product,11 which could not be
separated via recrystallization in either CH2Cl2/Et2O or NCMe/Et2O
from 6. In the 31P and 13C NMR spectra, the chemical shifts for 6 in
CDCl3 were identical with those from the crude reaction mixture of
2 with [RuCl2(PPh3)3] after 7 h. We interpret the formation of the
Cl
Cl
PPh3
N
N
Ru
As
Cl
Ph3P
PPh3
PPh3
N
O
O
Ru
Cl
As
+
- 2 PPh3
O
O
N
neutral complex [As(µ-PyO)2RuCl(PPh3)2] (5) as
elimination of PyO+ supported by free PPh3. 5 could be separated
from by crystallization (Figure 3). The capability of
a reductive
6
1
3
organophosphanes of performing mild reduction of As(III)
compounds has also been reported by Dostál et al..7a
Cl
N
Ph3P
N
PPh3
N
Cl
Ru
Cl
Ph3P
PPh3
PPh3
O
O
Ru
As
As
O
+
+ Cl
- PPh3
N
N
O
O
N
O
2
4
+ PPh3
Cl
Cl
Ph3P
N
PPh3
Figure 3. Molecular structure of 6. Ellipsoids are shown at 50%
probability level. Hydrogen atoms have been omitted for clarity.
Selected interatomic separations (Å) and angles (deg): P1-C6
1.786(4), P1-C12 1.792(4), P1-C18 1.783(3), P1-O1 1.587(3), O1-C1
1.408(5), N1-C1 1.309(5), C6-P1-C12 110.8(2), C6-P1-C18 112.1(2),
C12-P1-C18 110.0(2), P1-O1-C1 122.2(2), O1-C1-N1 116.1(3).
Ph3P
N
PPh3
N
Ru
As
+ AuCl(tht)
Ru
As
N
O
O
Au
Cl
O
O
7
5
+
Table 1. Selected bond lengths (Å) and angles (°) of 3, 5 and 7. For
the second molecule in the asymmetric unit of 5·2CHCl3
corresponding bond lengths and angles are reported after the slash.
O
Cl
PPh3 + PyOH + CCl4
Ph3P
N
- CHCl3
6
3
5
7
As1-Ru1
As1-Au1
Ru1-N1
Ru1-N2
Ru1-P1
Ru1-P2
Ru1-Cl1
Ru1/Au1-Cl2
As1-O1
As1-O2
As1-C1/Au1
N1-Ru1-N2
N1-Ru1-
P2/Cl1
N2-Ru1-P1
P1-Ru1-
2.2386(4)
2.3124(3) / 2.3019(3) 2.2919(5)
2.3283(6)
Scheme 2. Syntheses of 2-pyridyloxy-bridged Ru-As complexes.
2.112(3)
2.182(3)
2.299(1)
2.139(2) / 2.174(2)
2.184(2) / 2.137(2)
2.339(1) / 2.359(1)
2.353(1) / 2.336(1)
2.547(1) / 2.539(1)
2.172(3)
2.168(3)
2.391(1)
2.385(1)
2.459(1)
2.288(1)
1.869(3)
1.852(3)
2.3284(4)
79.79(12)
Further, the reaction of 2 with [RuCl2(PPh3)3] was investigated.
In the 31P NMR spectrum of the crude reaction mixture of 2 with
[RuCl2(PPh3)3] in CDCl3 after few minutes, one main signal at 34.1
ppm was detected in addition to the signal from free PPh3 (-5.4
ppm) and signals of much lower intensity at 39.8, 41.8 and 61.6
ppm (Figure S23). We attribute the signal at 34.1 ppm to the arsenic
complex [(O-PyO)As(µ-PyO)2RuCl(PPh3)2]Cl (4). This is supported
by the structurally related phosphorus complex [(O-PyO)P(µ-
2.414(1)
2.421(1)
1.811(2)
1.821(2)
1.905(3)
86.10(10)
172.23(7)
1.906(2) / 1.914(2)
1.889(2) / 1.896(2)
9
PyO)2RuCl(PPh3)2]PF6 which exhibits a PPh3 31P NMR signal at 36.4
ppm (CD2Cl2) whereas neutral complexes of type [(R)E(µ-
PyO)2RuCl2(PPh3)] (E = P, R = Ph, O-PyO; E = As, R = Ph) exhibit 31P
NMR signals for the ruthenium bonded PPh3 ligand in the range
41.0-41.7 ppm in chloroform solution.9 Furthermore the 13C NMR
signal of the PPh3 ligands´ ipso-carbon atoms exhibits the
characteristic multiplet encountered with cis-Ph3P-Ru-PPh3
arrangements (at 132.6 ppm, Figure S24). Therefore, the smaller
signal at 39.8 ppm was assigned to the complex [(O-PyO)As(µ-
PyO)2RuCl2(PPh3)]. Over time, in the 31P NMR spectrum of the crude
reaction mixture the intensities of the signals of 4, uncoordinated
PPh3 and [(O-PyO)As(µ-PyO)2RuCl2(PPh3)] decreased, whereby the
two signals at 41.8 and 61.6 ppm (reflecting an approximate 2:1
ratio, albeit acquisition parameter settings did not allow for
quantitative interpretation) gained intensity. After 7 h, the latter
two signals remained in the 31P NMR spectrum, thus indicating
82.81(7) / 79.65(3)
173.15(5) / 167.74(5) 168.35(9)
179.06(8)
89.31(3)
167.15(5) / 169.15(5) 168.35(9)
103.97(3)
P2/Cl1
As1-Ru1-Cl1
As1-Ru1-Cl2
O1-As1-O2
Ru1-As1-
C11/Au1
As1-Au1-Cl2
93.17(2)
168.96(2) / 168.86(1) 170.70(3)
169.85(2)
99.37(12)
149.43(10)
92.64(8) / 91.34(7)
92.23(15)
144.98(2)
176.67(3)
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
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DOI: 10.1039/D0DT01538E
Figure 4. Molecular structures of 3·1.5CHCl3 (left), 5·2CHCl3 (middle) and 7·CHCl3 (right). Ellipsoids are shown at 50% probability level.
Hydrogen atoms and solvent molecules have been omitted for clarity. For compound 5 only one of the two independent (but
conformationally similar) molecules in the asymmetric unit is shown as a representative example.
For compounds 3 and 5 we succeeded in growing crystals motif remains intact. Upon vapour diffusion of n-pentane into a
suitable for single-crystal X-ray diffraction analyses (Figure 4, Table CHCl3 solution of 7, crystals suitable for single-crystal X-ray
1). In 3 the ruthenium atom is distorted octahedral coordinated in diffraction have formed. The molecular structure of the expected
an all-cis configuration, and its molecular structure in 3·1.5CHCl3 complex [AuCl(As(µ-PyO)2)RuCl(PPh3)2] (7), featuring a hitherto
reveals the expected analogies with the related phosphorus
complex [PhP(µ-PyO)2RuCl2(PPh3)] (for molecular overlay see Figure
S25). Notably, the Ru1As1 bond is significantly shorter than the
shortest RuAs bonds reported so far (2.31 Å) by Powell et al..12,13
Nonetheless, the Ru1As1 bond is significantly longer than the
unprecedented Au-As-Ru core, is shown in figure 4 (right). The RuP
bonds in 7 are elongated (on average) by approximately 0.04 Å with
respect to compound 5. The As→Au coordination results in a
shortening of the Ru1Cl1 bond by approximately 0.08 Å (relative
to 5). With the wide Au1-As1-Ru1 angle of 144.98(2)° the As1
coordination sphere can again be described as intermediate
between seesaw and tetrahedral (τ4’ = 0.66).14 This coordination
sphere is different from the one of another literature reported
complex with Au-Pn-Ru motif (Pn = pnictogen): Bedford et al.
reported a heterodinuclear phosphaalkenyl complex, which has an
Au-P-Ru angle of 120.1(1)° due to the trigonal-planar coordination
sphere around the phosphaalkenyl ligand.15
corresponding
RuP
bond
in
the
related
complex
[PhP(µ-PyO)2RuCl2(PPh3)] (by about 0.1 Å), as expected for a larger
donor atom. Also, its As lone pair donor capability seems to be
weaker with respect to the related phosphorus complex, which is
reflected by significant shortening of the trans-disposed Ru1Cl2
bond by about 0.04 Å. The rather wide Ru1-As1-C11 angle
(149.4(1)°) allows to interpret the As coordination sphere (τ4’ =
0.62)14 as intermediate between seesaw (τ4’ ≤ 0.36, with α ≥ 90°)
and tetrahedral (τ4’ = 1).
Natural Bond Orbital Analysis
In complex 5 the ruthenium coordination sphere is distorted
octahedral. The angles around As1 are smaller than 97°, whereby
the As coordination sphere is best described as trigonal pyramidal.
In spite of the lower As coordination number, the average Ru-As
bond length is approximately 0.07 Å longer than in complex 3. (Also,
the Ru-P bonds are in average elongated by approximately 0.05 Å).
Interestingly, with respect to complex 3 even the AsO bonds are
elongated by approximately 0.07-0.10 Å in spite of the lower
coordination number of As1 in 5. This feature can be attributed to a
higher electron density around As1 in 5 than in 3 (i.e., lower
oxidation state and larger covalent radius), which is in accord with
the lower natural charge at As (3: NCAs = 1.70 e, 5: NCAs = 0.99 e).
Furthermore, in combination with the longer AsO bonds the
average OC bond lengths are significantly shorter in 5 than in 3 (by
approximately 0.021(7) Å), thus indicating a transition from the
In order to assign formal oxidation states and to investigate the
bond characteristics of compounds 3, 5 and 7, we performed
quantum chemical calculations. The natural localized molecular
orbital (NLMO) representative of the AsRu -bond exhibits
predominant As contribution in 3 (Table 2, Figure S26). The high
AsOC=N mode in 3 to the As←O=CN mode in 5.
Reactivity of 5 toward [AuCl(tht)]
As the arsenic atom in 5 exhibits a lone-pair, we were interested in
its ligand qualities. In spite of the bulky PPh3 ligands, a soft linear
coordinating metal (like gold(I)) should be able to utilize this Lewis
basic site. Treating a chloroform solution of 5 with [AuCl(tht)] (tht =
tetrahydrothiophene) leads to a high field shift of the 31P NMR
signal by about 4 ppm and retention of the characteristic multiplet
in the 13C NMR spectrum for the ipso-carbon, which is shifted from
135.9 (5) to 133.9 ppm (7), thus indicating that the cis-Ru(PPh3)2
Figure 5. NLMO representations of σ-(As→Au) bond (left) and σ-
(As→Ru) bond (right) in 7 are shown at an isosurface value of 0.06.
Only the ipso-carbon atoms of the PPh3 ligands are depicted, and H-
atoms are omitted for clarity.
4 | J. Name., 2012, 00, 1-3
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Cl
Cl
Cl
Ph3P
N
Ph3P
N
Ph3P
PPh3
N
PPh3
N
ViewPArPtihcl3e Online
DOI: 10.1039/D0DT01538E
RuII
AsI
RuI
AsII
Ru0
N
N
AsIII
Cl
O
O
O
O
O
O
Cl
N
PPh3
N
RuII
AsIII
5-L
5-X
5-Z
O
O
Cl
Cl
Cl
Ph3P
N
Ph3P
N
Ph3P
N
PPh3
N
PPh3
N
PPh3
N
RuII
AsI
RuI
AsII
RuII
AsII
3
O
O
O
O
O
O
AuI
Cl
AuI
Cl
Au0
Cl
7-L,L
7-X,L
7-L,X
Chart 3
4s-population from the As atom in that bond, and the high natural
charge (NC) of the As atom, speak for an AsIII→RuII canonical form,
the formal oxidation states of an (AuI←AsI→RuII) core. The lower NC
at RuII in comparison to AuI can be attributed to the better charge
where the electron pair at arsenic acts as donor towards ruthenium compensation by six ligands at ruthenium versus two ligands at
(Chart 3). In comparison to 3, the NCs of As and Ru in 5 dropped by
gold. For complexes 3, 5 and 7, π-(As←Ru) backbonding was found
0.71 and 0.17 e, respectively. At the arsenic atom a lone pair with
from the ruthenium 4dxz and 4dyz orbitals into the two vacant As 4p
predominant 4s character (78.1%, Figure S27) was found by NLMO
orbitals. Additionally, π-(As←Au) backbonding from the gold atom´s
5dxz and 5dyz was observed in complex 7 (Figure 6).
analysis. The σ-(AsRu) bond exhibits almost equal arsenic (51%)
and ruthenium (44%) contributions. To assign formal oxidation
states to the (As/Ru)III core in 5, the L/X/Z-formalism from Green
was considered.16 The reduction of the natural charges for both
atoms and their similar NLMO contributions are in support of the X-
type description with (AsII–RuI) core (5-X) as the formal AsRu-bond
situation in 5. The slight polarization towards As and the uneven
reduction of the natural charges, however, speak for a slight L-type
Table 2. Natural charges (NC in e) and NLMO characteristics of 3, 5
and 7.
3
5
7
NC(Ru)
NC(Au)
NC(As)
0.02
0.19
0.13
0.33
1.06
contribution in terms of an (AsI→RuII) core (5-L). The latter
1.70
0.99
contribution to the AsRu -bond clearly increases in 7, reflected
by the higher NC at Ru and less Ru contribution in the -AsRu
NLMO (Figure 5).
NLMO:
σ-(As-Ru)
29.1% Ru
68.0% As
As (64.2% 4s,
35.7% 4p)
44.8% Ru
51.2% As
As (14.3% 4s,
85.3% 4p)
33.6% Ru
5.7% Au
56.3% As
As (10.1% 4s,
89.7% 4p)
86.3%
Percentage of
parent NBO
NLMO:
94.1%
93.1%
2.2% Ru
10.2% Au
83.4% As
As (82.3% 4s,
17.5% 4p)
82.3%
σ-(As-Au)
Percentage of
parent NBO
NBO analysis aims at finding the optimal Lewis structure even
though multiple resonance forms are feasible. If deviation from this
localized form is present (e.g., in phenyl rings), an indication of
delocalization is given by a drop in NBO occupancy (percentage of
parent NBO in NLMO, the latter of which is set to accommodate
two electrons). In aromatic systems like phenyl rings this depletion
is approximately from ≈98% to ≈83%. A related loss of two-atomic
NBO contributions in the NLMOs is observed along the trimetallic
Au-As-Ru core. In this particular case, another indication of
Figure 6. NBO representations of π-(Au→As←Ru) backbonding in 7
are shown at an isosurface value of 0.06. Only the ipso-carbon
atoms of the PPh3 ligands are depicted, and H-atoms are omitted
for clarity.
The -(AsAu) bond clearly can be described as a donor-
acceptor interaction of the 4s-lone pair of As donating into the 6s-
orbital of Au. These results of NLMO analysis support assignment of
This journal is © The Royal Society of Chemistry 20xx
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delocalization is reflected by the noticeable Au contribution (5.7%) to pronounced metallic shared type rather than dVoienworA-raticclceeOpntlioner
in the σ-(As-Ru) NLMO.
interaction. This observation stands in cDoOntI:ra10s.t10t3o9/Dth0DeT0st1r5o3n8Eg
polarization of the σ-(As→Au) bond found by NBO analysis.
However, delocalization of Au contributions across the Au-As-Ru
core (into the -AsRu NLMO) is in agreement with the properties
at the AuAs BCP.
Quantum Theory of Atoms in Molecules
The topological analysis (atoms in molecules, AIM17) of complexes
3, 5 and 7 were conducted to shed light into the delocalization
effects observed in NLMO analysis. As the latter did not allow for a
direct comparison of highly localized two-center bonds, we
inspected the features of the individual bond critical points (BCPs,
Table 3). BCPs along the AsRu bond paths confirmed the presence
of AsRu bonds in 3, 5 and 7. The electron density (ρ(rb)) varies
within a narrow range (0.749-0.780 e·Å-3). Some topological
parameters at the BCP can be used to classify bond types. The ratio
V(rb) / G(rb) (with V(rb) = potential energy density, G(rb) =
Lagrangian kinetic energy) at the BCPs lays in the range 1 < V(rb) /
G(rb) < 218 and is thus indicative for an intermediate bond
characteristic (covalent bond with additional ionic contribution; 1 >
V(rb) / G(rb): pronounced ionic character; V(rb) / G(rb) > 2:
covalent interaction). The NCs (As: 1.06−1.70; Ru: −0.02 to −0.13 e)
are in support of attractive noncovalent bond contributions. The
Table 3. Selected features of the bond critical points (BCPs) of the
AsTM bonds in compounds 3, 5, and 7 derived from the
topological analyses (AIM).
Feature a
ρ(rb)
3 As-Ru
0.767
3.960
0.658
−1.039
1.579
0.859
−0.381
−0.497
0.238
5 As-Ru
0.780
1.310
0.482
−0.873
1.810
0.619
−0.390
−0.501
0.063
7 As-Ru
0.749
2.753
0.550
−0.908
1.650
0.735
−0.357
−0.478
0.094
7 As-Au
0.760
1.864
0.513
−0.895
1.745
0.674
−0.382
−0.503
0.007
∇2ρ(rb)
G(rb)
V(rb)
|V(rb)|/G(rb)
G(rb)/ρ(rb)
H(rb)
H(rb)/ρ(rb)
Ellipticity
magnitude of the ratio V(rb)
/ G(rb) (increase of covalent
Electron density (ρ(rb) in e·Å-3), Laplacian of electron density
a
characteristics) follows the order 3 < 7 < 5. According to Macchi et
al., the Laplacian of electron density (∇2ρ(rb)) is a good indicator for
the bond properties. For complex [Co2(CO)6(AsPh3)2], the authors
reported ∇2ρ(rb) of 1.344(8) e·Å-5 for the Co–Co bond as well as
(∇2ρ(rb) in e·Å-5), Lagrangian kinetic energy density (G(rb) in
Hartree·Å-3), potential energy density (V(rb) in Hartree·Å-3), ratio
|V(rb)|/G(rb), ratio G(rb)/ρ(rb) in Hartree·e-1, electron energy
density (H(rb) in Hartree·Å-3), ratio H(rb)/ρ(rb) in Hartree·e-1.
4.25(2) e·Å-5 and 4.21(2) e·Å-5 for the As→Co bonds.19 Whereas this
characteristic of the AsRu bond in 5 is similar to the former (thus
being closer to a nonpolar bond), the Laplacian of the AsRu bond
in 3 is closer to the latter, while the characteristics (also for the
AsAu bond) in 7 are intermediate. Also, the ratio G(rb)/ρ(rb)
provides information about the difference between shared
interactions (<1) and donor-acceptor interactions (≈1).19 The ratio
G(rb)/ρ(rb) is in general <1 and its magnitude decreases in the order
3 < 7 < 5. The conclusion from the trend of the Laplacian of the As-
TM bonds are in agreement with the trends found in the G(rb)/ρ(rb)
ratio. According to the group of topological parameters of the
Conclusions
Herein, the 2-pyridyloxy functionalized arsine ligands
PhAs(PyO)2 (1) and As(PyO)3 (2) have been synthesized and
characterized. In solution they exhibit dynamic isomerization
through exchange between AsO and AsN bonding modes.
Starting from As(PyO)3, we demonstrated a new synthesis method
to access low valent arsenic complexes via reductive elimination of
the auxiliary PyO ligand supported by PPh3 with formation of
[(PyO)PPh3]+Cl (6). The complex [As(µ-PyO)2RuCl(PPh3)2] (5) is the
product of this two electron reduction and exhibits a σ-(AsII–RuI)
core as dominant canonical form in addition to contributions of
As→Ru bonds described above, the bond characteristics are ranging
between closed shell donor-acceptor interaction (ρ(rb) = small;
G(rb)/ρ(rb) ≈ 1; H(rb) < 0; ∇2ρ(rb) > 0; 1 < V(rb) / G(rb) < 2) for
compounds 3 and 7 and metallic shared interaction (ρ(rb) = small;
G(rb)/ρ(rb) < 1; H(rb) < 0; ∇2ρ(rb) ≈ 0; 1 < V(rb) / G(rb) < 2) for
compound 5. The depletion of ELF (electron localization function)20
σ-(AsI→RuII) donor-acceptor characteristics. This is in contrast to the
formation of metallaboratranes, where reductive elimination (of a
hydrocarbon R-H) from a H-BIIIRuII-R core results in predominant
reduction of Ru with formation of a BIII←Ru0 dative bond.21 Addition
of an AuCl source leads to the formation of complex
[AuCl(As(µ-PyO)2)RuCl(PPh3)2] (7), featuring an Au-As-Ru core.
According to NBO and AIM calculations contributions of both
canonical forms σ-(AuI←AsI→RuII) and σ-(Au0–AsII→RuII) should be
taken into consideration for this trinuclear bonding situation. Due
between the As and Ru atoms in 3 and 7 supports the pronounced
donor-acceptor interaction in those complexes in comparison to
the As–Ru bond in 5 (Figure 7).
Noteworthy, the AIM properties at the BCP of the AsAu bond
in 7 are intermediate between those found for the AsRu bonds in
5 and 7. Also the ELF map exhibits a rather weak depletion between
gold and arsenic, which would hint at AsAu bond properties closer
to the coordination of the AuCl moiety to 5 an electron density shift
Figure 7. Electron Localization Function (ELF) of 3 (left), 5 (middle) and 7 (right).
6 | J. Name., 2012, 00, 1-3
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were carried out with ORCA 4.1.226 using DFT-PBEPVBieEwfAurtniccletiOonnlianle,
def2-TZVPP30 basis set for all atoms and effeDctOivI:e1c0o.1r0e39p/oDt0eDnTti0a1l5s3f8oEr
Ru [SD(28,MWB)] and Au [SD(60,MWB)].28 Starting from those
structures, NBO (Natural Bond Orbital) and NLMO (Natural
Localized Bond Orbital) calculations have been performed using
ORCA 4.1.226 with the NBO 6.0 package31 using DFT-B3LYP
functional (VWN-3) and for M = As, Ru: old-DKH-TZVPP, M = Au:
SARC-DKH-TZVPP and C, H, N, O, P, Cl: DKH-def2-TZVPP basis set
including Douglas-Kroll-Hess 2nd order scalar relativistic. NBO
in the AsRu bond results, which leads to a change of the formal X-
type AsIIRuI bond to an L-type AsI→RuII bonding mode and
therefore formal reduction of the arsenic atom caused by
coordination of an additional metal atom.
Experimental
General considerations
All preparations were carried out under an atmosphere of dry argon graphics were generated using ChemCraft.32 Topological analyses
using standard Schlenk techniques. [RuCl2(PPh3)3] was synthesized were performed with MultiWFN.33
following a literature protocol starting from elemental ruthenium.22
Synthesis of PhAs(PyO)2 (1)
[AuCl(tht)] was synthesized along a literature method starting from
elemental gold.23 PhP(PyO)2 was synthesized following the literature
method.9 Tetrahydrofuran (THF) and triethylamine (Et3N) were
distilled from sodium/benzophenone and stored under dry argon.
Dichloromethane (DCM) was distilled from calcium hydride and
stored under argon. Chloroform (stabilized with amylenes), n-
pentane and acetonitrile were stored over molecular sieves 3 Å. All
other chemicals used were commercially available and were used
without further purification.
PhAsCl2 used as starting material was synthesized along a slightly
modified method according to Michaelis et al.34 starting from
PhAsO. PhAsO (2.00 g, 11.9 mmol) and conc. HCl (60 mL) were
stirred at 60 °C for 20 min. The aqueous phase was extracted with
CH2Cl2 (3  5 mL). The combined organic phases were evaporated to
dryness (condensation of volatiles into a cold trap under reduced
pressure) and the residue was distilled at 120 °C/10 Torr (Yield: 1.70
g, 7.63 mmol, 64%).
In a Schlenk flask, 2-hydroxypyridine (500 mg, 5.26 mmol) and
triethylamine (638 mg, 6.30 mmol) were dissolved in THF (10 mL).
PhAsCl2 (586 mg, 2.63 mmol) was added dropwise, and the
resultant white suspension was stirred at ambient temperature for
3 h, whereupon the white precipitate of Et3NHCl was filtered and
washed with THF (3 mL). The combined filtrate and washings were
evaporated to dryness (condensation of volatiles into a cold trap
under reduced pressure), and the residue was recrystallized from
THF (1.5 mL). The white crystalline solid obtained after storing at
4 °C for one week was suitable for single-crystal X-ray diffraction.
The supernatant was decanted, the white solid was washed with
Et2O (3 mL) and dried in vacuo. The compound is highly
hygroscopic. Yield: 346 mg (1.01 mmol, 38%), in solution this
compound co-exists in two isomers;
Caution: Arsenic compounds such as AsCl3, PhAsCl2 and derivatives
thereof are highly toxic and, in case of AsCl3 and PhAsCl2, volatile.
Safety precautions need to be obeyed!
Materials and Equipment
Elemental analyses (C, H, N) were performed on a ‘Vario Micro
Cube’ analyzer (Elementar, Hanau, Germany).
Solution NMR spectra were recorded on an “Avance III 500” or
“Ascend NanoBay 400” spectrometer (Bruker Biospin, Rheinstetten,
Germany) and internally referenced to tetramethylsilane for 1H and
13C and externally referenced to 85% H3PO4 for 31P. The 31P{1H}
NMR spectra at “Avance III 500” were recorded as 1D sequence
with inverse gated decoupling using 30° flip angle and D1 = 5 s; at
“Ascend NanoBay 400” they were recorded as 1D sequence with
pulsed gated decoupling using 30° flip angle and D1 = 2 s. 90° 1H BB-
1H NMR (500.1 MHz, CDCl3): 6.40 (m, PyO-1II, 2H), 6.45 (m, PyO-1II,
2H), 6.77 (m, PyO-1II, 2H), 6.78-6.88 (m, PyO-1I/1II, 6H), 7.31-7.39
(m, meta/para-Ph-1II/1I, 9H), 7.43 (m, PyO-1II, 2H), 7.54 (m, PyO-1II,
2H), 7.59 (m, PyO-1I, 2H), 7.75 (m, ortho-Ph-1II, 6H), 7.86 (m, PyO-
1II, 2H), 7.89-8.01 (br. m, ortho-Ph-1I, PyO-1II/1I, 6H); 13C{1H} NMR
(125.8 MHz, CDCl3): 108.3 (PyO-1II), 111.2 (PyO-1I), 116.2 (PyO-1II),
116.8 (PyO-1I), 117.8 (PyO-1II), 128.3 (Ph), 128.5 (Ph), 130.3 (2xPh),
130.4 (2x PyO-1II, 2xPh), 137.3 (PyO-1II), 139.2 (PyO-1II), 139.4 (PyO-
1I), 141.2 (PyO-1II), 144.5 (ipso-Ph), 146.1 (ipso-Ph), 146.7 (PyO-1I),
163.9 (PyO-1II), 164.4 (PyO-1II), 166.9 (PyO-1I); elemental analysis
calcd. (%) for C16H13N2O2As·0.2H2O (343.81ꢀgꢁmol−1): C: 55.89, H:
3.93, N: 8.15; found: C: 55.98, H: 4.07, N: 8.27.
1
decoupling was used. Signals were assigned by using H,1H-COSY,
1H,13C-HSQC, 1H,13C-HMBC and 1H,1H-NOESY techniques.
Single-crystal X-ray diffraction data sets were collected with ω-
scans on an ‘IPDS-2(T)’ diffractometer (STOE, Darmstadt, Germany)
using Mo-Kα-radiation. Absorption correction was performed with
XShape using integration correction type. Structures were solved by
direct methods with ShelXS24 and all non-hydrogen atoms were
anisotropically refined in full-matrix least-squares cycles against
|F2| (ShelXL).25 Hydrogen atoms were placed in idealized positions
and refined isotropically (riding model). Selected parameters of
data collection are listed in tables S1 and S2. CIF files have been
deposited with the Cambridge Crystallographic Data Center (CCDC)
and can be obtained free of charge (for inquiry contact: CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK, fax: +44−1223−336033, e-
mail: deposit@ccdc.cam.ac.uk) quoting the following reference
numbers: CCDC-1994837 (6), 1994838 (2), 1994839 (3·1.5CHCl3),
1994840 (1), 1994841 (7·CHCl3), 1994842 (5·2CHCl3).
Computational analyses of 1, 2 and PhP(PyO)2 were carried out with
ORCA 4.1.225 using DFT-PBEPBE functional using cc-pVTZ27 basis set
for all atoms and effective core potential for As [SD(28,MWB)]28 and
D3BJ29 dispersion correction during geometry optimization (atomic
coordinates are given in the supporting information). Further
information of the optimization of the transition state of the
isomerization of 1II into 1I is given in the supporting information.
Optimization of the H-atom positions for complexes 3, 5, and 7
Synthesis of As(PyO)3 (2)
In a Schlenk flask, 2-hydroxypyridine (962 mg, 10.12 mmol) and
triethylamine (1.228 g, 12.14 mmol) were dissolved in THF (20 mL).
To the clear solution arsenic(III) chloride (611 mg, 3.37 mmol) was
added dropwise, and the resultant white suspension was stirred at
ambient temperature for 2 h. Thereafter, the white solid (Et3NHCl)
was filtered off and washed with THF (5 mL). From the combined
filtrate and washings all volatiles were evaporated in vacuo. The
residue was recrystallized in THF (2 mL). After one day storage at
room temperature, colorless crystals, suitable for single-crystal X-
ray diffraction, were obtained. The supernatant was decanted, the
solid was washed with diethyl ether (3 mL) and dried in vacuo.
Yield: 451 mg (1.26 mmol, 37%); 1H NMR (400.1 MHz, CDCl3): 6.57-
This journal is © The Royal Society of Chemistry 20xx
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7.02 (br. m, aryl, 6H), 7.60 (br. m, aryl, 3H), 8.01 (br. m, aryl, 3H); Synthesis of [Ph3P(PyO)]Cl (6)
View Article Online
13C{1H} NMR (100.6 MHz, CDCl3): 111.2 (br. s), 117.2 (br. s), 139.8 Triphenylphosphine (283 mg, 1.09 mmol) DaOnId: 102.-1h0y3d9r/Dox0yDpTy0r1i5d3in8Ee
(br. s), 146.3 (br. s), 164.2 (br. s); elemental analysis calcd. (%) for (100 mg, 1.05 mmol) were dissolved in acetonitrile (1 mL) and
C15H12N3O3As (MW = 357.20ꢀgꢁmol−1): C: 50.44, H: 3.39, N: 11.76; stirred for 1.5 h at 60 °C. The clear solution was evaporated to
found: C: 50.11, H: 3.69, N: 11.51.
dryness, and the residue was dissolved in dichloromethane (2 mL).
After one week of vapor diffusion of diethyl ether at room
temperature, colorless crystals suitable for single-crystal X-ray
diffraction were obtained. The supernatant was decanted, the
crystalline solid was washed with diethyl ether (2 mL) and dried in
vacuo. Yield: 302 mg (purity: ~89%, 3% impurity of Ph3P=O and 8%
impurity of [Ph3PCH2Cl]Cl; attempts of purification via additional
recrystallization from CH2Cl2/Et2O or NCMe/Et2O were not
successful);
Synthesis of [PhAs(µ-PyO)2)RuCl2(PPh3)] (3)
PhAs(PyO)2 (93 mg, 273 µmol) and [RuCl2(PPh3)3] (262 mg, 273
µmol) were dissolved in chloroform (1 mL). The dark red solution
was stirred at ambient temperature for 10 min, whereupon stirring
was stopped. After one day of vapor diffusion of diethyl ether into
the chloroform solution at room temperature, orange crystals
suitable for single-crystal X-ray diffraction were obtained. The
supernatant was decanted, the solid was washed with diethyl ether
1H NMR (500.1 MHz, CDCl3): 7.25 (m, PyO, 1H), 7.62 (m, PyO, 1H),
7.75 (br. m, 6H), 7.82-7.96 (br. m, 9H), 7.99-8.07 (br. m, 2H); 13C{1H}
(3 mL) and dried in vacuo. Yield: 138 mg (144 µmol, 53%).
Cl
3
NMR (125.8 MHz, CDCl3): 112.5 (d, JC,P = 8.5 Hz, C3, PyO), 118.0 (d,
Cl
N
1JC,P = 107.6 Hz, ipso-Ph), 121.7 (s, C5, PyO), 139.2 (d, 3JC,P = 14.0 Hz,
PPh3
4
N
Ru
As
2
meta-Ph), 132.8 (d, JC,P = 12.2 Hz, ortho-Ph), 135.2 (m, para-Ph),
5
6
3
N
2
141.4 (s, C4, PyO), 145.7 (s, C6, PyO), 155.2 (d, 2JC,P = 9.2 Hz, C2, PyO);
1
1
31P{1H} NMR (202.5 MHz, CDCl3): 61.6 (s, 13C satellites: JC,P = 107.6
2
O
O
O
Hz).
Synthesis of [AuCl(As(µ-PyO)2)RuCl(PPh3)2] (7)
4
3
1H NMR (500.1 MHz, CDCl3): 6.19 (ddd, JH,H = 1.39 Hz, JH,H = 6.71
[RuCl(PPh3)2(As(PyO)2)] (5) (40 mg, 38 µmol) and [AuCl(tht)] (14 mg,
44 µmol) were dissolved in chloroform (1 mL) and stirred at
ambient temperature for 5 min. The clear solution obtained was
layered with n-pentane (10 mL) and stored undisturbed at room
temperature for crystallization. The supernatant was decanted, the
solid was washed with n-pentane (1 mL) and dried in vacuo.
Thereafter, the solid was dissolved in CHCl3 and exposed to vapour
diffusion of n-pentane to afford crystals suitable for single-crystal X-
Hz, JH,H = 7.65 Hz, H5 (PyO-2), 1H), 6.80 (dd, JH,H = 1.39 Hz, JH,H
=
3
4
3
8.20 Hz, H3 (PyO-2), 1H), 6.96-7.10 (br. m, meta-PPh3, H3 (PyO-1), H5
4
3
(PyO-1), para-PPh3, 11H), 7.23 (ddd, JH,H = 1.85 Hz, JH,H = 7.65 Hz,
3JH,H = 8.20 Hz, H4 (PyO-2), 1H), 7.43 (m, ortho-AsPh, 2H), 7.57-7.63
(br. m, meta-AsPh, para-AsPh, H4 (PyO-1), 4H), 7.73 (m, ortho-PPh3,
6H), 8.71 (dd, JH,H = 1.85 Hz, JH,H = 6.71 Hz, H6 (PyO-2), 1H), 9.74
(br. m, H6 (PyO-1), 1H); 13C{1H} NMR (125.8 MHz, CDCl3): 109.8 (s, C3
(PyO-2)), 110.6 (s, C3 (PyO-1)), 117.5 (s, C5 (PyO-2)), 118.3 (s, C5
4
3
1
ray diffraction. Yield: 32 mg (27 µmol, 71%); H NMR (400.1 MHz,
3
4
3
CDCl3): 6.37 (m, H5, 2H), 6.56 (d, JH,H = 8.28 Hz, H3, 2H), 7.11 (m,
(PyO-1)), 127.6 (d, JC,P = 9.61 Hz, meta-PPh3), 129.1 (d, JC,P = 1.80
Hz, para-PPh3), 124.9 (s, meta-AsPh), 130.2 (s, ortho-AsPh), 132.8 (s,
para-AsPh), 133.6 (d, JC,P = 9.59 Hz, ortho-PPh3), 134.7 (d, JC,P
3
3
4
meta-PPh3, 12H), 7.19 (ddd, JH,H = 8.28 Hz, JH,H = 7.02 Hz, JH,H
=
2
3
1.86 Hz, H4, 2H), 7.26 (t, JH,H = 7.36 Hz, para-PPh3, 6H), 7.38 (m,
3
=
2.37 Hz, ipso-AsPh), 135.0 (d, 1JC,P = 45.5 Hz, ipso-PPh3), 137.7 (s, C4
(PyO-2)), 139.8 (s, C4 (PyO-1)), 149.5 (s, C6 (PyO-1)), 152.3 (s, C6
(PyO-2)), 162.8 (s, C2 (PyO-1)), 163.4 (s, C2 (PyO-2)); 31P{1H} NMR
(202.5 MHz, CDCl3): 40.7 (s); elemental analysis calcd. (%) for
C34H28AsCl2N2O2PRu·1.4CHCl3·0.2Et2O (MW = 956.42ꢀgꢁmol−1): C:
45.46, H: 3.31, N: 2.93; found: C: 45.44, H: 3.38, N: 2.84.
ortho-PPh3, 12H), 8.93 (d, JH,H = 6.14 Hz, H6, 2H); 13C{1H} NMR
3
(100.6 MHz, CDCl3): 111.2 (s), 116.5 (br. s), 127.8 (dd, J = 4.62 Hz, J =
4.69 Hz), 129.6 (s), 133.9 (br. m, ipso-PPh3), 134.5 (dd, J = 3.89 Hz, J
= 4.81 Hz), 138.7 (s), 148.4 (s), 165.1 (s, C2); 31P{1H} NMR (162.0
MHz, CDCl3): 38.0 (s); elemental analysis calcd. (%) for
C46H38AsAuCl2N2O2P2Ru·0.25CHCl3 (MW
=
1186.46ꢀgꢁmol−1): C:
46.82, H: 3.25, N: 2.36; found: C: 46.81, H: 3.25, N: 2.31.
Synthesis of [As(µ-PyO)2)RuCl(PPh3)2] (5)
As(PyO)3 (105 mg, 294 µmol) and [RuCl2(PPh3)3] (282 mg, 294
µmol) were dissolved in chloroform (10 mL) and stirred at ambient
temperature for 3 days. The solution was filtered through Celite,
and diethyl ether (20 mL) was added to the filtrate. The mixture was
stored at -24 °C for one week to afford a crystalline product. The
supernatant was decanted, the yellow solid was washed with
diethyl ether (8 mL) and dried in vacuo. Crystals suitable for single-
crystal X-ray diffraction were obtained by recrystallization from
chloroform. Yield: 174 mg (165 µmol, 56%);
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
The authors thank Ute Groß for performing the elemental
analyses.
1H NMR (400.1 MHz, CDCl3): 6.26 (dd, 3JH,H = 6.54 Hz, 3JH,H = 6.33 Hz,
3
H5, 2H), 6.35 (d, JH,H = 8.20 Hz, H3, 2H), 7.01 (m, meta-PPh3, H4,
3
14H), 7.15 (t, JH,H = 7.34 Hz, para-PPh3, 6H), 7.37 (m, ortho-PPh3,
Notes and references
3
12H), 9.08 (d, JH,H = 6.33 Hz, H6, 2H); 13C{1H} NMR (100.6 MHz,
1
a) J. S. Jones, F. P. Gabbaï, Acc. Chem. Res., 2016, 49, 857-
867. b) D. You, F. P. Gabbaï, J. Am. Chem. Soc., 2017, 139,
6843−6846. c) C. R. Wade, I.-S. Ke, F. P. Gabbaï, Angew.
Chem. Int. Ed., 2012, 51, 478-481. d) D. Gallego, A. Brück, E.
Irran, F. Meier, M. Kaupp, M. Driess, J. F. Hartwig, J. Am.
Chem. Soc., 2013, 135, 15617-15626. e) C. Jones, S. J. Black,
J. W. Steed, Organometallics, 1998, 17, 5924-5926. f) S.
CDCl3): 111.0 (s), 114.9 (br. s), 127.3 (dd, J = 4.50 Hz, J = 5.06 Hz),
128.7 (s), 134.2 (dd, J = 4.40 Hz, J = 5.14 Hz), 135.9 (br. m, ipso-
PPh3), 137.3 (s), 149.2 (s), 167.8 (s, C2); 31P{1H} NMR (162.0 MHz,
CDCl3): 41.8 (s); elemental analysis calcd. (%) for
C46H38AsClN2O2P2Ru·1.1CHCl3 (MW = 1055.51ꢀgꢁmol−1): C: 53.60, H:
3.73, N: 2.65; found: C: 53.65, H: 3.95, N: 2.66.
8 | J. Name., 2012, 00, 1-3
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Journal Name
Bestgen, N. H. Rees, J. M. Goicoechea, Organometallics, 32 Chemcraft
ARTICLE
ver.
1.8
(build
164),
2016;
View Article Online
2018, 37, 4147-4155.
http://www.chemcraftprog.com/.
2
a) E. Wächtler, L. A. Oro, M. Iglesias, B. Gerke, R. Pöttgen, R. 33 T. Lu, F. Chen, J. Comput. Chem., 2012,D3O3I,: 5108.100–3599/D20. DT01538E
Gericke, J. Wagler, Chem. Eur. J., 2017, 23, 3447–3454. b) J. 34 A. Michaelis, W. LaCoste, A. Michaelis, Liebigs Ann. Chem.,
S. Jones, C. R. Wade, M. Yanga, F. P. Gabbaï, Dalton Trans.,
2017, 46, 5598–5604. c) K. Toyota, Y. Wakisaka, Y.
Yamamoto, K. Akiba, Organometallics, 2000, 19(24), 5122-
5133.
1880, 201, 184-261.
3
4
5
6
7
J. T. Price, M. Lui, N. D. Jones, P. J. Ragogna, Inorg. Chem.,
2011, 50, 12810−12817.
S. Burck, J. Daniels, T. Gans-Eichler, D. Gudat, K. Nättinen, M.
Nieger, Z. Anorg. Allg. Chem., 2005, 631, 1403-1412.
C. M. Thomas, G. P. Hatzis, M. J. Pepi, Polyhedron, 2018, 143,
215–222.
J. W. Dube, P. J. Ragogna, Chem. Eur. J., 2013, 19, 11768–
11775.
a) V. Kremláček, J. Hyvl, W. Y. Yoshida, A. Růžička, A. L.
Rheingold, J. Turek, R. P. Hughes, L. Dostál, M. F. Cain,
Organometallics, 2018, 37, 2481−2490. b) M. Kořenková, V.
Kremláček, M. Erben, R. Jirásko, F. De Proft, J. Turek, R.
Jambor, A. Růžička, I. Císařovád, L. Dostál, Dalton Trans.,
2018, 47, 14503–14514. c) M. Kořenková, M. Hejda, R.
Jirásko, T. Block, F. Uhlik, R. Jambor, A. Ržika, R. Pöttgen, L.
Dostál, Dalton Trans., 2019, 48, 11912-11920.
E. A. V. Ebsworth, R. O. Gould, R. A. Mayo, M. Walkinshaw,
Dalton Trans., 1987, 11, 2831-2838.
8
9
R. Gericke, J. Wagler, Polyhedron, 2017, 125, 57–67.
10 S. S. Garje, V. K. Jain, Main Group Met. Chem. 1997, 20, 755-
760.
11 R. Appel, K. Warning, K.-D. Ziehn, Liebigs Ann. Chem., 1975,
406-409.
12 Cambridge Structure Database, CSD v.5.40, 2019.
13 R. H. B. Mais, H. M. Powell, J. Chem. Soc., 1965, 7471-7481.
14 τ4’ was calculated as reported: A. Okuniewski, D. Rosiak, J.
Chojnacki, B. Becker, Polyhedron, 2015, 90, 47-57
15 R. B. Bedford, A. F. Hill, C. Jones, A. J. P. White, D. J. Williams,
J. D. E. T. Wilton-Ely, Chem. Commun., 1997, 2, 179-180.
16 M. H. L. Green, J. Organomet. Chem., 1995, 500, 127-148.
17 R. F. W. Bader, Atoms in Molecules, Clarendon Press, Oxford,
1994.
18 E. Espinosa, I. Alkorta, J. Elguero, E. Molins, J. Chem. Phys.,
2002, 117, 5529-5542.
19 P. Macchi, D. M. Proserpio, A. Sironi, J. Am. Chem. Soc., 1998,
120, 13429-13435.
20 A. D. Becke, K. E. Edgecombe, J. Chem. Phys., 1990, 92, 5397-
5403.
21 A. F. Hill, G. R. Owen, A. J. P. White, D. J. Williams, Angew.
Chem., Int. Ed., 1999, 38, 2759-2761.
22 R. Gericke, J. Wagler, Polyhedron 2016, 120, 134-141.
23 R. Uson, A. Laguna, M. Laguna, D. A. Briggs, H. H. Murray, J.
P. Fackler, Inorg. Synth., 1989, 26, 85-91.
24 G. M. Sheldrick, Acta Crystallogr., 2008, A64, 112-122.
25 G. M. Sheldrick, Acta Crystallogr., 2015, C71, 3-8.
26 a) F. Neese, WIREs Comput. Mol. Sci., 2012, 2, 73-78. b) F.
Neese, WIREs Comput. Mol. Sci., 2018, 8, e1327.
27 a) T. H. Dunning, Jr., J. Chem. Phys., 1989, 90, 1007. b) A. K.
Wilson, D. E. Woon, K. A. Peterson, T. H. Dunning, Jr., J.
Chem. Phys., 1999, 110, 7667.
28 D. Andrae, U. Häußermann, M. Dolg, H. Stoll, H. Preuss,
Theor. Chim. Acta., 1990, 77, 123-141.
29 S. Grimme, J. Antony, S. Ehrlich, H. Krieg, J. Chem. Phys.,
2010, 132, 154104.
30 F. Weigend, R. Ahlrichs, Phys. Chem. Chem. Phys., 2005, 7,
3297-3305.
31 E. D. Glendening, J. K. Badenhoop, A. E. Reed, J. E. Carpenter,
J. A. Bohmann, C. M. Morales, C. R. Landis, F. Weinhold, NBO
6.0 (Theoretical Chemistry Institute, University of Wisconsin,
Madison, WI, 2013); http://nbo6.chem.wisc.edu/.
This journal is © The Royal Society of Chemistry 20xx
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DOI: 10.1039/D0DT01538E
2-Pyridyloxy bridged RuII-AsIII-complexes were shown capable of reductively eliminating an As-bound
substituent with formation of RuI-AsII and, upon coordinating AuCl at the vacant As lone pair, RuII-AsI
complexes.