Preparation of Neutral trans - Cis [Ru(O2CR)2P2(NN)], Cationic [Ru(O2CR)P2(NN)](O2CR) and Pincer [Ru(O2CR)(CNN)P2] (P = PPh3, P2= diphosphine) Carboxylate Complexes and their Application in the Catalytic Carbonyl Compounds Reduction

Article abstract of DOI:10.1021/acs.organomet.1c00059

The diacetate complexes trans-[Ru(κ1-OAc)2(PPh3)2(NN)] (NN = ethylenediamine (en) (1), 2-(aminomethyl)pyridine (ampy) (2), 2-(aminomethyl)pyrimidine (ampyrim) (3)) have been isolated in 76-88% yield by reaction of [Ru(κ2-OAc)2(PPh3)2] with the corresponding nitrogen ligands. The ampy-type derivatives 2 and 3 undergo isomerization to the thermodynamically most stable cationic complexes [Ru(κ1-OAc)(PPh3)2(NN)]OAc (2a and 3a) and cis-[Ru(κ1-OAc)2(PPh3)2(NN)] (2b and 3b) in methanol at RT. The trans-[Ru(κ1-OAc)2(P2)2] (P2 = dppm (4), dppe (5)) compounds have been synthesized from [Ru(κ2-OAc)2(PPh3)2] by reaction with the suitable diphosphine in toluene at 95 °C. The complex cis-[Ru(κ1-OAc)2(dppm)(ampy)](6) has been obtained from [Ru(κ2-OAc)2(PPh3)2] and dppm in toluene at reflux and reaction with ampy. The derivatives trans-[Ru(κ1-OAc)2P2(NN)] (7-16; NN = en, ampy, ampyrim, 8-aminoquinoline; P2 = dppp, dppb, dppf, (R)-BINAP) can be easily synthesized from [Ru(κ2-OAc)2(PPh3)2] with a diphosphine and treatment with the NN ligands at RT. Alternatively these compounds have been prepared from trans-[Ru(OAc)2(PPh3)2(NN)] by reaction with the diphosphine in MEK at 50 °C. The use of (R)-BINAP affords trans-[Ru(κ1-OAc)2((R)-BINAP)(NN)] (NN = ampy (11), ampyrim (15)) isolated as single stereoisomers. Treatment of the ampy-type complexes 8-15 with methanol at RT leads to isomerization to the cationic derivatives [Ru(κ2-OAc)P2(NN)]OAc (8a-15a; NN = ampy, ampyrim; P2 = dppp, dppb, dppf, (R)-BINAP). Similarly to 2, the dipivalate trans-[Ru(κ1-OPiv)2(PPh3)2(ampy)] (18) is prepared from [Ru(κ2-OPiv)2(PPh3)2] (17) and ampy in CHCl3. The pincer acetate [Ru(κ1-OAc)(CNNOMe)(PPh3)2] (19) has been synthesized from [Ru(κ2-OAc)2(PPh3)2] and HCNNOMe ligand in 2-propanol with NEt3 at reflux. In addition, the dppb pincer complexes [Ru(κ1-OAc)(CNN)(dppb)] (CNN = AMTP (20), AMBQPh (21)) have been obtained from [Ru(κ2-OAc)2(PPh3)2], dppb, and HAMTP or HAMBQPh with NEt3, respectively. The acetate NN and pincer complexes are active in transfer hydrogenation with 2-propanol and hydrogenation with H2 of carbonyl compounds at S/C values of up to 10000 and with TOF values of up to 160000 h-1.

Full text of DOI:10.1021/acs.organomet.1c00059

pubs.acs.org/Organometallics
Article
Preparation of Neutral trans - cis [Ru(O2CR)2P2(NN)], Cationic
[Ru(O2CR)P2(NN)](O2CR) and Pincer [Ru(O2CR)(CNN)P2] (P = PPh3, P2
= diphosphine) Carboxylate Complexes and their Application in the
Catalytic Carbonyl Compounds Reduction
̈
Salvatore Baldino, Steven Giboulot, Denise Lovison, Hans Gunter Nedden, Alexander Pöthig,
Antonio Zanotti-Gerosa, Daniele Zuccaccia, Maurizio Ballico,* and Walter Baratta*
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ABSTRACT: The diacetate complexes trans-[Ru(κ1-OAc)2(PPh3)2(NN)] (NN =
ethylenediamine (en) (1), 2-(aminomethyl)pyridine (ampy) (2), 2-(aminomethyl)-
pyrimidine (ampyrim) (3)) have been isolated in 76−88% yield by reaction of [Ru(κ2-
OAc)2(PPh3)2] with the corresponding nitrogen ligands. The ampy-type derivatives 2
and 3 undergo isomerization to the thermodynamically most stable cationic complexes
[Ru(κ1-OAc)(PPh3)2(NN)]OAc (2a and 3a) and cis-[Ru(κ1-OAc)2(PPh3)2(NN)]
(2b and 3b) in methanol at RT. The trans-[Ru(κ1-OAc)2(P2)2] (P2 = dppm (4), dppe
(5)) compounds have been synthesized from [Ru(κ2-OAc)2(PPh3)2] by reaction with
the suitable diphosphine in toluene at 95 °C. The complex cis-[Ru(κ1-OAc)2(dppm)-
(ampy)](6) has been obtained from [Ru(κ2-OAc)2(PPh3)2] and dppm in toluene at
reflux and reaction with ampy. The derivatives trans-[Ru(κ1-OAc)2P2(NN)] (7−16;
NN = en, ampy, ampyrim, 8-aminoquinoline; P2 = dppp, dppb, dppf, (R)-BINAP) can
be easily synthesized from [Ru(κ2-OAc)2(PPh3)2] with a diphosphine and treatment
with the NN ligands at RT. Alternatively these compounds have been prepared from trans-[Ru(OAc)2(PPh3)2(NN)] by reaction
with the diphosphine in MEK at 50 °C. The use of (R)-BINAP affords trans-[Ru(κ1-OAc)2((R)-BINAP)(NN)] (NN = ampy (11),
ampyrim (15)) isolated as single stereoisomers. Treatment of the ampy-type complexes 8−15 with methanol at RT leads to
isomerization to the cationic derivatives [Ru(κ2-OAc)P2(NN)]OAc (8a−15a; NN = ampy, ampyrim; P2 = dppp, dppb, dppf, (R)-
BINAP). Similarly to 2, the dipivalate trans-[Ru(κ1-OPiv)2(PPh3)2(ampy)] (18) is prepared from [Ru(κ2-OPiv)2(PPh3)2] (17) and
ampy in CHCl3. The pincer acetate [Ru(κ1-OAc)(CNNOMe)(PPh3)2] (19) has been synthesized from [Ru(κ2-OAc)2(PPh3)2] and
HCNNOMe ligand in 2-propanol with NEt3 at reflux. In addition, the dppb pincer complexes [Ru(κ1-OAc)(CNN)(dppb)] (CNN =
AMTP (20), AMBQPh (21)) have been obtained from [Ru(κ2-OAc)2(PPh3)2], dppb, and HAMTP or HAMBQPh with NEt3,
respectively. The acetate NN and pincer complexes are active in transfer hydrogenation with 2-propanol and hydrogenation with H2
of carbonyl compounds at S/C values of up to 10000 and with TOF values of up to 160000 h−1.
labile ligands that can dissociate easily, allowing a free site for
substrate coordination and formation of the catalytically active
species. With regard to ruthenium, which has been widely
employed in homogeneous catalysis for its high performance
and versatility,2 it is worth mentioning that ruthenium
carboxylates have been shown to catalyze the hydrogenation
(HY) of olefins3 and carbonyl compounds.4 These types of
complexes can also promote alcohol dehydrogenation5 and the
cycloisomerization of alkynols to five- to seven-membered
INTRODUCTION
■
The ever-increasing need to produce valuable organic
compounds by industry requires the development of new
and more efficient homogeneous transition-metal catalysts.
Selective transformations can be achieved through an
appropriate choice of ligands at the metal, leading to well-
designed catalysts characterized by high productivity. Poly-
dentate nitrogen and phosphine ligands have been extensively
employed with the aim to obtain robust and catalytically active
species. More recently, the use of carboxylates as ancillary
ligands has been demonstrated to be particularly promising in
many catalytic processes, since carboxylate may play a non-
innocent role, acting as a proton acceptor for H−H and C−H
splitting reactions1 and stabilizing monomeric species on
account of the facile switching capability from a mono- to a
bidentate mode of coordination. Furthermore, carboxylates are
Received: February 1, 2021
Published: April 14, 2021
© 2021 The Authors. Published by
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Scheme 1. Synthesis of Diacetate Ruthenium Complexes with PPh3 and NN Ligands
endocyclic enol ethers.6 Ruthenium carboxylate catalysts have
been found to activate C−H bonds,7 promote functionaliza-
tion reactions,8 efficiently direct C−H/C−O bond arylations
with phenols in water,9 and react with aldehydes.10 Ruthenium
phosphine carboxylate complexes have been reported to
catalyze the hydrogenation of carboxylic acids and their
derivatives to alcohols,11 while the employment of BINAP-
Ru(II) dicarboxylates12 afforded the asymmetric hydrogena-
tion of unsaturated carboxylic acids to the corresponding
s a t u r a t e d p r o d u c t s . 1 3 F u r t h e r m o r e , [ R u -
(O2CR)2(CO)2(PPh3)2] (R = CH2OCH3, iPr, tBu, 2-
cC4H3O, Ph) were successfully applied as catalysts in the
addition of carboxylic acids to propargylic alcohols to give the
corresponding β-oxo esters used in the pharma industry.14
Among organic transformations entailing ruthenium catalysts,
the reduction of carbonyl compounds via HY15 and transfer
hydrogenation (TH)16 are environmentally benign methods
and core processes accepted by the industry for the synthesis of
alcohols. Several highly efficient ruthenium catalysts have been
developed for both TH and HY, namely [RuCl(η6-arene)-
(TsDPEN)]12,17 and trans-[RuCl2P2(diamine)] (P2 = diphos-
phine) complexes, which represent a milestone for these types
of catalytic processes.18 The employment of the ampy12 ligand
in place of diamines has resulted in the isolation of cis-
[RuCl2P2(ampy)] derivatives that show high catalytic activity
for enantioselective TH and HY.19 In addition, the related
pincer CNN complexes [RuCl(CNN)P2], containing function-
alized ampy ligands, have proved to be exceptionally
productive catalysts for TH and HY, including those of
biomass-derived carbonyl compounds.20 The replacement of
the chloride in trans-[RuCl2P2(diamine)] with sterically
hindered carboxylates as anionic ligands has resulted in the
highly efficient catalysts [Ru(OCOR)2P2(en)]12 (P2 = dppe,
OAc; NN = en, ampy: P2 = dppb, dppf),12 the trifluoroacetate
[Ru(OCOCF3)2(dppb)(XCH2CH2X)]23 (X = NH2, OH)
derivatives, and the mixed acetate acetylacetonate complex
[Ru(OAc)(acac)(dppb)(ampy)]24 have been proven to be
highly active catalysts in the TH and HY reductions. The
pincer CNN ruthenium acetate complex [Ru(OAc)(AMTP)-
(dppb)]12 has shown the highest activity in TH with a TOF
value ot up to 3.8 × 106 h−1, consistent with the easier
substitution of the carboxylate vs Cl in protic media.25 Acetate
ruthenium compounds in combination with carbene ligands,
namely [RuBr(OAc)(PPh3)(P-aNHC)] and [Ru(OAc)(P-
aNHC)2]Br (P-aNHC = phosphine-abnormal-NHC ligands),
have displayed high rates and productivities in TH and in fast
Oppenauer-type oxidation reactions (TOFs of up to 600000
h−1).26 With regard to other applications, ruthenium
carboxylate complexes have been described as efficient
photosensitizers for TiO2 semiconductor solar cells.27 New
anticancer agents have been prepared by employing ruthenium
carboxylate complexes with the aim of obtaining compounds
with good solubility in the culture medium.28 We have recently
reported the synthesis of a new class of cationic carboxylate
ruthenium complexes, [Ru(κ1-OCOR)(CO)(dppb)(phen)]-
(OCOR)12 (R = Me, Bu), that display high cytotoxic activity
t
against anaplastic thyroid cancer cell lines, with EC50 values
much lower than that of cisplatin, leading to an increment of
apoptosis and decrease in cancer cell aggressiveness.29
This paper discloses a convenient procedure for the
preparation of a series of neutral trans/cis and cationic
carboxylate ruthenium complexes containing bidentate nitro-
gen and phosphine ligands through straightforward syntheses
t
by starting from the [Ru(κ2-OCOR)2(PPh3)2] (R = Me, Bu)
xantphos;12 R = Bu, Ph, 1-adamantyl) for the selective HY of
t
precursors. Pincer CNN acetate complexes have also been
easily obtained through this synthetic route. The carboxylate
ruthenium complexes show activity in TH and HY reactions,
allowing the reduction of carbonyl compounds at S/C values
of up to 10000 and TOF values of up to 160000 h−1.
aldehydes under base-free or acidic conditions.21
During our studies aiming to expand the use of ruthenium
carboxylates in catalysis, we have found that the cationic
monocarbonyl derivatives [RuX(CO)P2(NN)]X22 (X = Cl,
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respectively. The diastereotopic methylene protons of the
ampy ligand appear as two doublets at δ 4.10 and 3.92 (d,
2J(H,H) = 16.1 Hz) for the cationic complex 2a, while the cis
derivative 2b displays these signals at δ 4.48 and 4.42. Control
1H NMR experiments show that adding sodium acetate (1.0
and 3.5 equiv) to the 2a,b mixture in CD3OD showed a
progressive increase in the signal at δ 1.93 attributed to the free
acetate of the cationic derivative 2a, confirming the proposed
structure (see Figure S10 in the Supporting Information), as
observed for [Ru(κ2-OAc)(PPh3)(NN)(CO)]OAc (NN = en,
ampy).22 Finally, in the 13C{1H} NMR spectrum the carbonyl
acetate carbon atoms of the cationic 2a are at δ 190.3 and
180.3, while the acetate resonances of the cis derivative 2b are
at δ 191.7 and 190.4.
RESULTS AND DISCUSSION
■
Synthesis of Diacetate Ruthenium Complexes with
PPh3 and NN Ligands. Treatment of [Ru(κ2-OAc)2(PPh3)2]
with 1 equiv of en in methyl ethyl ketone (MEK) at room
temperature for 45 min affords the complex trans,cis-[Ru(κ1-
OAc)2(PPh3)2(en)] (1), isolated in 84% yield (Scheme 1).
1
The H NMR spectrum of 1 in CDCl3 displays two broad
singlets at δ 5.31 and 2.67 for the amino and the methylene
groups of the en ligand, respectively, with a singlet at δ 1.67 for
the methyl acetate. In a fashion similar to that for 1, the
derivative trans,cis-[Ru(κ1-OAc)2(PPh3)2(ampy)] (2) is syn-
thesized in high yield (85%) by the reaction of [Ru(κ2-
OAc)2(PPh3)2] with ampy at room temperature in MEK or
dichloromethane (Scheme 1 and methods 1 and 2 in the
Experimental Section). Alternatively, 2 has been obtained in
76% yield through a one-pot reaction from [RuCl2(PPh3)3],
NaOAc and ampy in acetone via the intermediate [Ru(κ2-
OAc)2(PPh3)2] (method 3). The 31P{1H} NMR spectrum of 2
in CD2Cl2 exhibits two doublets at δ 44.6 and 39.4 with a
2J(P,P) value of 31.3 Hz, whereas the methylene protons of the
ampy appear in the 1H NMR spectrum as a broad multiplet at
δ 4.18 and the NH2 signal is at δ 6.70. This downfield chemical
shift is consistent with the presence of a NH···OC
hydrogen-bond interaction of the NH2 protons with the two
acetate ligands, in contrast with the related complexes trans-
[Ru(κ1-OAc)2P2(ampy)] (P2 = DiPPF, DCyPF)12 containing a
bulky diphosphine,30 in which only one NH interacts with an
acetate group.31
The reaction of [Ru(κ2-OAc)2(PPh3)2] with ampyrim12
leads to species similar to those observed with ampy. Thus, the
complex trans,cis-[Ru(κ1-OAc)2(PPh3)2(ampyrim)] (3) is
quickly obtained from [Ru(κ2-OAc)2(PPh3)2] and ampyrim
in MEK at room temperature and isolated in 88% yield
(Scheme 1). Complex 3 isomerizes in methanol at RT within
48 h, leading to a 2:1 mixture of the cationic complexes cis-
[Ru(κ2-OAc)(PPh3)2(ampyrim)]OAc (3a) and cis,cis-[Ru(κ1-
OAc)2(PPh3)2(ampyrim)] (3b), isolated in 78% yield
(Scheme 1). The 31P{1H} NMR spectroscopic data of 3a,b
resemble those of the analogue ampy derivatives 2a,b, with two
doublets at δ 58.8 and 47.7 with 2J(P,P) = 32.8 Hz for 3a and
2
at δ 64.3 and 49.0 with J(P,P) = 28.0 Hz for 3b.
Synthesis of Diacetate Ruthenium Complexes with
Diphosphines and NN Ligands. The synthesis of Ru acetate
complexes with the ligands dppm and dppe12 has been
R e c e n t l y , w e r e p o r t e d t h a t t r a n s - [ R u ( κ 1 -
OAc)2(DiPPF)2(NN)] derivatives, displaying the bulky
diphosphine DiPPF, are quickly obtained from [Ru(κ2-
OAc)2(DiPPF)] and NN (en, ampy) at low temperature.31
While the en complex is thermally stable, the ampy compound
undergoes rapid isomerization at room temperature to the
thermodynamically most stable cationic and cis complexes in
methanol. Accordingly, dissolution of 2 in methanol at RT for
24 h afforded a mixture of the cationic cis-[Ru(κ2-OAc)-
(PPh3 )2 (ampy)]OAc (2a) and cis,cis-[Ru(κ1 -
OAc)2(PPh3)2(ampy)] (2b) in a 3:2 molar ratio (method
1), isolated in 85% yield (Scheme 1). Alternatively, the same
mixture is formed from [Ru(κ1-OAc)2(PPh3)2] and ampy in
methanol at RT and was isolated in 83% yield (method 2).
Attempts to isomerize 2 to 2a,b in toluene at 100 °C failed,
leading to decomposition with release of PPh3, as inferred from
31P{1H} NMR analysis. The 31P{1H} NMR spectrum of 2a,b
in CD3OD displays two doublets at δ 60.2 and 47.1 (2J(P,P) =
32.6 Hz) for the cationic complex 2a and two doublets at δ
65.0 and 49.0 (2J(P,P) = 29.3 Hz) for the cis isomer 2b. The
doublet at δH 7.98 (3J(H,H) = 5.7 Hz) and the multiplet a δH
8.20 are for the ortho pyridine signals of 2a and 2b,
reported by Wong et al. by starting from [Ru(κ2-
OAc)2(PPh3)2] and the diphosphines in toluene at reflux for
12 h. With dppm the cationic [Ru(κ2-OAc)(dppm)]OAc was
isolated, whereas with dppe a mixture of the three isomers cis-
and trans-[Ru(κ1-OAc)2(dppe)2] and the cationic [Ru(κ2-
OAc)(dppe)]OAc were formed and were separated by
fractional crystallization.32 A reexamination of this procedure
under milder reaction conditions show that the trans-[Ru(κ1-
OAc)2(P2)2] (P2 = dppm (4), dppe (5)) derivatives (δP −5.9
and 44.7, respectively) have been obtained as single products
in 68% and 71% yields, respectively, by treatment of [Ru(κ2-
Scheme 2. Synthesis of cis-[Ru(κ1-OAc)2(dppm)(ampy)] (6)
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Scheme 3. Synthesis of Neutral trans-[Ru(κ1-OAc)2P2(NN)]
(P2 = Diphosphine) Complexes
OAc)2(PPh3)2] with 2 equiv of dppm or dppe in toluene at 95
°C for 20 min (eq 1).
The reaction of [Ru(κ2-OAc)2(PPh3)2] with 1 equiv of
dppm in MEK at room temperature afforded a mixture of
trans-[Ru(κ1-OAc)2(dppm)2] (4) and the unreacted precursor.
Addition of an excess of ampy (1.2 equiv) at RT results in a
partial decoordination of dppm from 4, with the formation of
trans-[Ru(κ1-OAc)2(dppm)(ampy)] in the presence of 4 in a
2:1 molar ratio, as inferred from NMR analysis (see Figures
S23 and S24 in the Supporting Information). Interestingly, the
thermodynamically most stable isomer, cis-[Ru(κ1-
OAc)2(dppm)(ampy)] (6), has been isolated in 76% yield
from [Ru(κ2-OAc)2(PPh3)2] and dppm (1 equiv) in toluene at
reflux (4 h), followed by reaction with ampy at 95 °C for 12 h,
via the intermediate [Ru(κ1-OAc)2(dppm)(PPh3)] species32
(Scheme 2).
The 31P{1H} NMR spectrum of 6 in CDCl3 displays two
doublets at δ 23.4 and 7.9 with 2J(P,P) = 94.4 Hz, whereas the
methylene protons of the ampy ligand give a doublet of
3
doublets at δH 3.58 (2J(H,H) = 16.1 Hz and J(H,H) = 5.0
Hz) and a multiplet at δH 3.32. A 15N−1H HSQC 2D NMR
analysis reveals that the NH2 signals are at δ 9.74 and 1.13
ppm, consistent with the presence of one NH···O hydrogen
bond interaction with one acetate. The 1H NMR spectrum of 6
in CD3OD shows two resonances at δ 2.03 and 1.66 for the
methyl groups, indicating that the OAc ligands are
coordinated, as was also confirmed by addition of NaOAc
(1.0−3.5 equiv) to 6 (δH 1.92 for the free OAc) (see Figure
S27 in the Supporting Information). Attempts to isolate the
analogous dppe derivative by the reaction of [Ru(κ2-
OAc)2(PPh3)2] with dppe in toluene and treatment with
ampy failed, resulting in the formation of two [Ru-
(OAc)2(dppe)(ampy)] species in the presence of uncharac-
terized complexes (see Figures S31 and S32 in the Supporting
Information). The employment of diphosphines with a longer
backbone leads to the isolation of trans diphosphine/NN
derivatives at room temperature. The reaction of [Ru(κ2-
OAc)2(PPh3)2] with dppf in CH2Cl2 at RT for 1 h, followed by
reaction with en for 30 min, affords the complex trans-[Ru(κ1-
OAc)2(dppf)(en)] (7), isolated in 90% yield (Scheme 3).
An X-ray diffraction experiment carried out for 7 shows that
this complex crystallizes in a distorted-octahedral geometry
with two trans acetate groups (Figure 1).
Complex 7 displays Ru−O (2.109(3), 2.118(3) Å) distances
in line with the data reported for analogous monodentate
diacetate ruthenium complexes,32,33 with the Ru−N (2.164(4),
2.155(3) Å) distances being slightly shorter in comparison to
those of the related dichloride compound trans-[RuCl2(dppf)-
(en)] (Ru−N 2.167(3), 2.171(3) Å)) and consistent with the
strong trans influence exerted by the diphosphine.32,34 The
O1−Ru1−O3 angle is almost linear (174.90(10)°) and is
greater with respect to that of the analogous chloride
compound (Cl−Ru−Cl angle of 166.31(4)°). The solid-state
study of 7 also revealed the presence of intramolecular
hydrogen-bond interactions between the CO acetate oxygen
atoms with the axial N−H protons of the en ligand with O···H
distances of 1.913 and 2.019 Å.23,33 The 1H NMR spectrum of
7 in solution (CD2Cl2) displays one triplet at δ 2.64 for the
two CH2N groups and one broad signal for the four NH
hydrogens, shifted to low field at δ 4.92, consistent with a
hydrogen-bond interaction with the acetate. The ampy
derivative trans-[Ru(κ1-OAc)2(dppp)(ampy)] (8) (85%
yield) has been prepared from [Ru(κ2-OAc)2(PPh3)2] and
dppp12 in CH2Cl2, followed by treatment with ampy at RT
(Scheme 3, method 1). Alternatively, 8 (93% yield) has been
obtained in acetone (method 2) and also by reaction of 2 with
dppp in MEK (50 °C, 20 h), by PPh3 substitution (61% yield)
(method 3). The 31P{1H} NMR spectrum of 8 displays two
2
doublets at δ 47.8 and 33.1 with J(P,P) = 49.l Hz, while the
NH2 protons give a broad singlet at δH 6.27, indicating a NH···
O hydrogen bond. The diacetate derivatives trans-[Ru(κ1-
OAc)2(dppb)(ampy)] (9) and trans-[Ru(κ1-OAc)2(dppf)-
(ampy)] (10) have been synthesized in 61−88% yields by
the reaction of Ru(κ2-OAc)2(PPh3)2] with the corresponding
diphosphine (dppb, dppf) and ampy in CH2Cl2 or acetone,
following the procedure described for 8. Complexes 9 and 10
have also been prepared by starting from 2 and the
diphosphine dppb or dppf, respectively, and isolated in 70−
73% yield. Treatment of (R)-BINAP with [Ru(κ2-
OAc)2(PPh3)2] in toluene at reflux for 24 h, followed by
reaction with ampy (RT, 1 h), afforded trans-[Ru(κ1-
OAc)2((R)-BINAP)(ampy)] (11) in 59% yield as a single
stereoisomer (Scheme 3). The 31P{1H} NMR spectrum of 11
in CD2Cl2 exhibits two doublets at δ 54.9 and 40.9 with
2J(P,P) = 36.9 Hz, whereas the 1H NMR spectrum reveals two
broad signals for the NH2 protons interacting with the acetate
1
ligands at δ 6.91 and 5.06, as inferred from a H−15N HSQC
2D NMR analysis (see Figure S61 in the Supporting
Information). In analogy to the ampy complexes, the ampyrim
derivatives trans-[Ru(κ1-OAc)2P2(ampyrim)] (P2 = dppp (12),
dppb (13), dppf (14)) have been isolated in good yield (77−
85%) by reaction of [Ru(κ2-OAc)2(PPh3)2] with diphosphine
and ampyrim in CH2Cl2 at RT (method 1 for 12−14).
Alternatively, 12−14 have been prepared from 3 and a
diphosphine in MEK at 50 °C (57−80% yields) (Scheme 3).
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Scheme 4. Synthesis of Cationic [Ru(κ2-OAc)P2(NN)]OAc
(P2 = Diphosphine) Complexes
Figure 1. ORTEP style plot of compound 7 in the solid state (CCDC
2058063). Ellipsoids are drawn at the 50% probability level. The
phenyl groups are simplified as wireframes for clarity (as well as
disorder of one phenyl group is not shown). Selected bond lengths
(Å) and angles (deg): Ru1−O1 2.109(3), Ru1−O3 2.118(3), Ru1−
N1 2.164(4), Ru1−N2 2.155(3), Ru1−P1 2.2934(11), Ru1−P2
2.2816(11), O1−Ru1−O3 174.90(10), O1−Ru1−N2 87.73(13),
O3−Ru1−N2 92.89(13), O1−Ru1−N1 89.91(13), O3−Ru1−N1
85.28(13), N2−Ru1−N1 77.99(13), O1−Ru1−P2 92.37(8), O3−
Ru1−P2 92.69(8), N2−Ru1−P2 89.74(9), N1−Ru1−P2 167.42(10),
N2−Ru1−P2 89.74(9), N1−Ru1−P2 167.42(10), O1−Ru1−P1
95.44(8), O3−Ru1−P1 83.23(8), N2−Ru1−P1 171.04(10), N1−
Ru1−P1 93.61(10), P2−Ru1−P1 98.48(4). Hydrogen-bond dis-
tances measured for O2···H1A and O4···H2A are 1.913 and 2.019 Å,
respectively.
free acetates, respectively. The cationic complexes [Ru(κ2-
OAc)P2(ampy)]OAc(P2 = dppb (9a), dppf (10a)) have been
prepared from 9 and 10 in methanol at RT and isolated in 95−
98% yields (Scheme 4). The 31P{1H} NMR spectra show the
typical doublet patterns for the two complexes at δP 58.2 and
46.0 (2J(P,P) = 37.2 Hz) and at δP 59.9 and 49.5 (2J(P,P) =
35.4 Hz) for 9a and 10a, respectively. The 1H NMR spectra of
these complexes in CD3OD show diastereotopic CH2N
2
protons (δ 4.03 and 3.60, with J(H,H) = 16.4 Hz for 9a)
and a singlet at δ 1.92 for the methyl group of the free acetate,
as for 8a. The coordinated acetate ligands of 9a and 10a appear
as doublets at δC 189.7 and 190.8, while the free acetate
appears at δC 180.4. In a similar way the cationic ampyrim
derivatives [Ru(κ2-OAc)P2(ampyrim)]OAc (P2 = dppp (12a),
dppb (13a), dppf (14a)) have been quantitatively isolated
(87−98% yield) from the corresponding trans isomers in
CH3OH, the NMR data resembling those of the analogous
ampy complexes. The isomerization of the BINAP derivatives
11 and 15 in methanol at RT leads to the cationic [Ru(κ2-
OAc)((R)-BINAP)(NN)]OAc (NN = ampy (11a), ampyrim
(15a)) in 86−96% yields as a mixture of two isomers in about
a 2:1 molar ratio for 11a and 1:1 for 15a, respectively (Scheme
4), as inferred from NMR measurements in CD3OD. Complex
11a shows a two doublets at δP 61.1 and 52.4 (2J(P,P) = 38.8
Hz) for the major isomer and two doublets at δP 68.3 and 58.1
(2J(P,P) = 38.7 Hz) for the minor species. Finally, the two
singlets at δH 1.50 and 1.41 are assigned to the methyl acetate
ligands of the two isomers, whereas the signal at δH 1.92 is
assigned to the free acetate.
Complex 12 shows two doublets at δP 47.9 and 32.6 with
2J(P,P) = 50.1 Hz, whereas the multiplets at δH 8.52 and 8.41
are ascribed to NCH protons of the pyrimidine. The chiral
complex trans-[Ru(κ1-OAc)2((R)-BINAP)(ampyrim)] (15)
(63% yield) has been synthesized from [Ru(κ2-OAc)2(PPh3)2]
and (R)-BINAP in toluene at reflux and treatment with
ampyrim in acetone at RT. Through a one-pot reaction trans-
[Ru(κ1-OAc)2(dppb)(8-aminoquinoline)] (16) (90% yield) is
obtained from [Ru(κ2-OAc)2(PPh3)2], dppb, and 8-amino-
quinoline in CH2Cl2 at RT (Scheme 3). Complex 16 displays
two doublets at δP 50.5 and 37.2 (2J(P,P) = 36.7 Hz), whereas
the multiplet at δH 9.23 is attributed to the proton in position 2
of the 8-aminoquinoline, shifted to low field in comparison to
the free ligand (δ 8.77),35 while the broad singlet at δH 8.24 is
ascribed to the amino group.
The trans acetate derivatives trans-[Ru(κ1-OAc)2P2(NN)],
bearing ampy-type ligands, isomerize to the thermodynamically
most stable cationic complexes [Ru(κ2-OAc)P2(NN)]OAc in
methanol, without formation of the neutral cis derivative. Thus,
[Ru(κ2-OAc)(dppp)(ampy)]OAc (8a) is obtained in 90%
yield by dissolution of 8 in MeOH at room temperature
(Scheme 4).
Synthesis of Dipivalate Ruthenium Complexes with
PPh3 and ampy. The precursor [Ru(κ2-OPiv)2(PPh3)2] (17)
has been isolated in 75% yield by treatment of [RuCl2(PPh3)3]
with sodium pivalate in tert-butyl alcohol at 70 °C by a slight
modification of the synthesis reported by Wilkinson3d (Scheme
5).
Complex 8a shows in the 31P{1H} NMR spectrum in
Reaction of 17 with ampy in chloroform at RT affords the
pivalate ruthenium derivative trans,cis-[Ru(κ1 -
OPiv)2(PPh3)2(ampy)]12 (18), isolated in 85% yield (Scheme
5). Complex 18 shows two 31P{1H} NMR doublets at δ 45.8
2
CD3OD two doublets at δ 55.2 and 36.7 with J(P,P) = 48.4
Hz. The doublet at δH 8.09 (3J(H,H) = 5.7 Hz) is ascribed to
the ortho pyridine proton, while the two singlets at δH 1.52 and
1.92 are assigned to the methyl group of the coordinated and
2
and 38.5 with J(P,P) = 30.5 Hz. The ampy NCH2 protons
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Scheme 5. Synthesis of the Pivalate 17 and the ampy Derivative 18
Scheme 6. Synthesis of Pincer CNN Ruthenium Acetate Complexes
appear as a broad multiplet at δH 4.03, with the NH2 signal
superimposed on those of the aromatic protons, in agreement
with a NH···O interaction, whereas the pivalate CO groups
give a doublet at δC 188.2 (3J(C,P) = 1.3 Hz).
complex [Ru(κ1-OAc)(AMTP)(dppb)] (20) (85% yield) has
been obtained from [Ru(κ2-OAc)2(dppb)] with HAMTP12
and NEt3 in 2-propanol at reflux (Scheme 6). Alternatively, 20
can be prepared (46% yield) directly from [Ru(κ2-
OAc)2(PPh3)2], dppb, and HCNN, through a one-pot
reaction. Notably, this new route is more straightforward for
preparative scope, with respect to that described, involving the
protonation with HOAc of the air- and moisture-sensitive
isopropoxide [Ru(OiPr)(AMTP)(dppb)], which equilibrates
with the hydride complex [RuH(AMTP)(dppb)].25 Similarly
to 20, the benzo[h]quinoline CNN derivative [Ru(κ1-OAc)-
(AMBQPh)(dppb)] (21) (59% yield) was obtained from
[Ru(κ2-OAc)2(dppb)], HAMBQPh,12 and NEt3 in 2-propanol
at reflux (Scheme 6). Conversely, 21 (65% yield) can also be
synthesized by a one-pot reaction from [Ru(κ2-
OAc)2(PPh3)2], dppb, and HAMBQPh. In CD2Cl2 21 shows
two doublets at δP 59.8 and 44.9 with 2J(P,P) = 37.9 Hz, while
the NH2 resonances are at δH 8.61 and 0.98, consistent with a
N−H···O interaction as for 19 and 20.25 Finally, the broad
singlet at δC 180.4 is assigned to the carboxylate, a value close
Synthesis of Pincer CNN Ruthenium Acetate Com-
plexes. The pincer acetate complex [Ru(κ1-OAc)(CNNOMe)-
(PPh3)2] (19) has been easily prepared in 75% yield by
treatment of [Ru(κ2-OAc)2(PPh3)2] with the ligand
12
HCNNOMe in the presence of the weak base NEt3 (10
equiv) in 2-propanol at reflux, through the elimination of acetic
acid and cyclometalation (Scheme 6).
The 31P{1H} NMR spectrum of 19 in CD2Cl2 shows two
2
doublets at δ 57.2 and 52.9 with J(P,P) = 33.3 Hz, whereas
the signals of the NH2 group are at δH 8.86 and 1.92. The low-
field resonance is consistent with an intramolecular NH···O
hydrogen bond interaction with the acetate ligand (see Figure
117 in the Supporting Information). The singlet at δ 7.68 is
attributed to the CH proton close to the ortho-metalated
carbon atom, while the diastereotopic CH2N gives a doublet of
doublets at δ 4.09 (2J(H,H) = 17.3 Hz and 3J(H,H) = 6.0 Hz)
and a multiplet at δ 3.42. Finally, the cyclometalated carbon
2
to that of the doublet of doublets at δC 180.3 with J(C,P) =
2
appears at δC 185.5 (dd with J(C,P) = 14.3 and 8.4 Hz),
16.1 and 8.8 Hz for the Ru−C atom.
Catalytic Reduction of Carbonyl Compounds via TH
and HY Reactions. The acetate complexes display good to
whereas the signal at δ 180.1 can be attributed to the
carboxylate CO group. Accordingly, the diphosphine pincer
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Scheme 7. TH and HY of Ketones and Aldehydes Catalyzed by Ruthenium Diacetate Complexes 7−11, 16, and 21
high catalytic activity in the reduction of the CO bond with
2-propanol in the presence of base and H2 under pressure (S/
C = 1000−10000) (Scheme 7).
The ethylenediamine dppf derivative 7 displays poor activity
in the TH of model substrate acetophenone a (0.1 M) in 2-
propanol at reflux with NaOiPr (2 mol %), affording 1-
phenylethanol (59% of conversion) in 20 h at S/C = 2000
(Table 1, entry 1). Conversely, the related ampy complex 10
trans 9 and the cationic 9a lead to the same catalytically active
species (Table 1, entries 3−6). Use of the (R)-BINAP complex
11 (S/C = 2000) affords 94% conversion in 5 h, but with poor
enantioselectivity (30% ee; entry 8), while the 8-aminoquino-
line derivative 16 gives incomplete reduction (29% conversion
in 5 h). Finally, the pincer complex 21 was proven to be highly
efficient in the TH of a, giving quantitative conversion in 20
min at S/C = 10000 and TOF = 160000 h−1 (entry 9), a value
comparable to that observed using the corresponding chloride-
containing complex.20b,c,25 Catalysts 8, 10, and the pincer 21
were tested in the reduction of (bulky) ketones. Thus, 8 and
10 (at S/C = 5000) catalyze the quantitative reduction of tert-
butyl phenyl ketone b to 2,2-dimethyl-1-phenyl-1-propanol in
18 and 20 h, respectively (Table 2, entries 1 and 2), whereas
the pincer CNN compound 21 leads to 90% conversion in 18
Table 1. Catalytic TH of Acetophenone a (0.1 M) with
Complexes 7−11 and 21 (S/C = 2000−10000) and NaOiPr
(2 mol %) in 2-Propanol at 82 °C
a
b
entry complex
S/C
time
20 h
4 h
20 h
10 min
20 h
20 min
3 h
5 h
conversion (%) TOF (h−1
)
1
2
3
4
5
6
7
8
9
7
8
9
9
9a
9a
10
11
21
2000
10000
10000
2000
10000
2000
10000
2000
10000
59
95
87
90
87
93
90
94
97
70
5200
1200
11000
1300
21000
28000
Table 2. Catalytic TH of Carbonyl Compounds (0.1 M) to
Alcohols with Complexes 8, 10, and 21 (S/C = 2000−
10000) and NaOiPr (2 mol %) in 2-Propanol at 82 °C
a
b
c
conversion
(%)
TOF
(h−1
6400
160000
entry substrate complex
S/C
time
20 h
18 h
18 h
20 h
18 h
2 h
1.5 h
10 min
5 min
20 h
18 h
)
20 min
1
2
3
4
b
b
b
c
8
5000
5000
5000
10000
10000
10000
5000
5000
5000
2000
2000
96
98
99
86
78
85
98
98
99
700
1800
2500
a
b
Conversions have been determined by GC analyses. Turnover
10
21
8
frequency (moles of ketone converted to alcohol per mole of catalyst
c
per hour) at 50% conversion. 30% ee.
1800
5
6
7
8
9
10
11
c
c
10
21
8
10
21
8
19000
59000
19000
30000
150000
1100
shows a significantly higher activity with S/C = 10000, leading
to 90% of the alcohol in 3 h (TOF = 28000 h−1; entry 7). The
ampy compounds 8 and 9, bearing the dppp and dppb ligands,
give 95% and 87% conversion of a in 3 and 20 h, respectively,
at S/C = 10000 (entries 2 and 3). The use of a higher amount
of 9 (S/C = 2000) leads to a dramatic increase in the activity
(90% conversion in 10 min, TOF = 11000 h−1; entry 4), thus
indicating that the dppb derivative undergoes easier
deactivation with respect to the ferrocenyl diphosphine
complex.
d
d
d
e
e
c
86
d
10
98
7000
a
b
Conversions have been determined by GC analyses. Turnover
frequency (moles of ketone converted to alcohol per mole of catalyst
c
per hour) at 50% conversion. Mixture of diastereoisomeric alcohols:
(+)-neomenthol (58%), (+)-isomenthol (11%), (−)-menthol (15%),
d
The cationic dppb derivative 9a shows an activity (87% and
93% conv. at S/C 10000 and 2000) comparable with that of 9,
suggesting that under these catalytic conditions the neutral
(+)-neoisomenthol (16%). Mixture of diastereoisomeric alcohols:
(+)-neomenthol (65%), (+)-isomenthol (11%), (−)-menthol (15%),
(+)-neoisomenthol (9%).
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Table 3. HY of Carbonyl Compounds (2 M) with Complexes 7, 9, 10, and 19 under H2 with KOtBu (2 mol %) after 16 h
a
a
a
entry
complex
substrate
S/C
solvent
T (°C)
p(H2) (atm)
conversion (%)
alcohol (%)
byproducts (%)
1
2
3
4
5
7
a
a
a
f
10000
10000
10000
1000
EtOH
EtOH
EtOH
MeOH
MeOH
40
40
70
50
50
30
30
30
20
20
99
99
40
56
>99
99
99
40
55
93
10
19
9
b
9
g
1000
6
a
b
The HY experiments were carried out in an eight-vessel Endeavor Biotage system, and the conversions were determined by GC analysis. 3-
phenylpropan-1-ol.
h, with rates lower than those observed for the TH of a (entry
3). Benzophenone c was converted to benzhydrol (86 and 78%
yields) at S/C = 10000 in 18−20 h with 8 and 10 (entries 4
and 5), whereas with the pincer 21 the reaction is faster with
85% conversion in 2 h (entry 6). Complex 8 catalyzes the TH
of d, leading to cyclohexanol (98% conversion) at S/C = 5000
in 1.5 h (TOF = 19000 h−1, entry 7), while with 10 and 21,
substrate d is quantitatively reduced in 10 and 5 min,
respectively, with TOF values of 30000 and 150000 h−1,
which much of the same values obtained for a (entries 8 and
9). Complexes 8 and 10 promote the reduction of
(−)-menthone e to (+)-neomenthol as the main isomer in
58 and 65% yields, in addition to (+)-isomenthol,
(−)-menthol, and (+)-neoisomenthol (entries 10 and 11).
A comparison of the activity of the acetate vs the analogous
chloride complexes show that the latter undergo a slightly
shorter induction period for the formation of the catalytically
active species with NaOiPr, whereas the productivity depends
on the stereoelectronic properties of the diphosphine, dppf
being strongly beneficial to achieving efficient TH.19a,d
Complexes 7, 9, 10, and 19 were also studied in the
hydrogenation (HY) of ketones and aldehydes (2 M) at 20−30
atm of H2 pressure and 40−70 °C in ethanol or methanol with
KOtBu at S/C values of up to 10000 (Scheme 7). The HY
reactions have been carried out in a catalyst screening system
(eight-vessels Endeavor Biotage system), which allows parallel
reactions to be followed.
The en and ampy derivatives 7 and 10 catalyze the
quantitative HY of a at 40 °C under 30 atm of H2 pressure
with S/C = 10000 in EtOH (Table 3, entries 1 and 2), whereas
the pincer 19 shows low activity (40% conversion) at 70 °C
(entry 3). Complex 9 catalyzes the HY of benzaldehyde f with
low conversion (55%) at 50 °C in MeOH (S/C = 1000)
(entry 4). Conversely, 9 promotes the complete HY of trans-
cinnamaldehyde g, affording cinnamyl alcohol (93%) as the
main product of the CO reduction and 3-phenylpropan-1-ol
(6%) as a byproduct of the additional CC HY (entry 5). In
addition, the cationic isomer 9a displays very poor activity in
the HY of f in MeOH with 12% conversion.
group, affording the corresponding hydride species, i.e.
[RuH(CNN)(dppb)], a reaction which is facilitated by the
cis NH2 function.38a,40 The low activity of the PPh3 pincer
derivatives in HY may be ascribed to the formation of trans-
[RuH(CNNOMe)(PPh3)2], in which the H is trans to N, with
respect to the more active [RuH(CNN)(dppb)], where H is
trans to P, affording a more hydridic hydride species (see
Figure S127 in the Supporting Information).19d,41
CONCLUDING REMARKS
■
In conclusion, we have described the preparation of a class of
carboxylate ruthenium complexes containing PPh3 and
diphosphines in combination with bidentate NN ligands.
Neutral trans and cis complexes of the formula [Ru-
(OCOR)2P2(NN)] and the cationic complexes [Ru(O2CR)-
P2(NN)](O2CR) have been isolated through straightforward
syntheses from [Ru(κ2-OCOR)2(PPh3)2], a diphosphine, and
NN ligands. While the trans diamine derivatives [Ru(κ1-
OAc)2P2(en)] are thermally stable, the related 2-
(aminomethyl)pyridine-type complexes trans-[Ru(κ1-
OAc)2P2(NN)] easily undergo isomerization at room temper-
ature to the more stable cis-[Ru(κ1-OAc)2P2(NN)] and/or the
cationic [Ru(κ1-OAc)P2(NN)]OAc complexes in methanol. In
addition, pincer complexes of the formula [Ru(κ1-OAc)-
(CNN)P2] have been obtained from [Ru(κ2-OAc)2(PPh3)2]
via facile cyclometalation of HCNN ligands, and with an
additional diphosphine, through a one-pot reaction. The
described complexes show good to high catalytic activity in
the transfer hydrogenation and hydrogenation of carbonyl
compounds. Studies to extend this protocol to the preparation
of ruthenium carboxylate complexes with NN and CNN pincer
ligands and their application in catalytic organic trans-
formations are currently in progress.
EXPERIMENTAL SECTION
■
All reactions were carried out under an argon atmosphere using
standard Schlenk techniques. The solvents were carefully dried by
standard methods and distilled under argon before use. The
ruthenium complexes [RuCl2(PPh3)3],42 [Ru(κ2-OAc)2(PPh3)2],3d
and [Ru(κ2-OAc)2(dppb)]32 and the ligands HAMTP,20h
With regard to the mechanism of the TH and HY
reductions, it is likely that the catalytically active mono- or
dihydride Ru species are obtained from the ruthenium
carboxylate precursors by reaction with alkoxides or H2.36
For the TH reactions in 2-propanol, the presence of an amino
group cis to the Ru carboxylate allows the easy formation of
Ru−H species via a Ru amide complex and alcohol37 or via a
Ru amine/alkoxide intermediate.37−40 In the HY reactions in
basic alcohol media, H2 splitting leads to the formation of the
ruthenium hydride active species from the carboxylate
precursor through a 16-electron Ru amide complex38b,c or
via a Ru amine/alkoxide derivative.39 The CNN pincer
derivatives undergo elimination of the labile carboxylate
20a
20b
HCNNOMe
,
and HAMBQPh
were prepared according to
literature procedures, whereas all other chemicals were purchased
from Aldrich and Strem and used without further purification. NMR
measurements were recorded on Bruker AC 200 and Avance III HD
NMR 400 spectrometers. Chemical shifts (ppm) are relative to TMS
1
for H and 13C{1H}, whereas H3PO4 was used for 31P{1H}. Infrared
measurements were obtained with a Bruker Vector 22 FTIR
spectrometer. Elemental analyses (C, H, N) were carried out with a
Carlo Erba 1106 analyzer, whereas GC analyses were performed with
a Varian CP-3380 gas chromatograph equipped with a 25 m length
MEGADEX-ETTBDMS-β chiral column with hydrogen (5 psi) as the
carrier gas and a flame ionization detector (FID).
Synthesis of trans,cis-[Ru(κ1-OAc)2(PPh3)2(en)] (1). [Ru(κ2-
OAc)2(PPh3)2] (100 mg, 0.134 mmol) and en (9.6 μL, 0.142 mmol,
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1.06 equiv) were stirred in MEK (2 mL) at room temperature for 45
min. Addition of n-pentane (2 mL) afforded a yellow precipitate that
was filtered, washed with n-pentane (2 mL), and dried under reduced
pressure. Yield: 90 mg (84%). Anal. Calcd for C42H44N2O4P2Ru
(803.84): C, 62.76; H, 5.52; N, 3.49. Found: C, 62.85; H, 5.60; N,
16.1 Hz, 1H; CH2N major isomer), 1.93 (s, 3H; OCOCH3 major
isomer), 1.70 (s, 3H; OCOCH3 minor isomer), 1.36 (s, 3H;
OCOCH3 minor isomer), 1.15 (s, 3H; OCOCH3 major isomer).
2
13C{1H} NMR (100.6 MHz, CD3OD, 25 °C): δ 191.7 (d, J(C,P) =
2.2 Hz; OCOCH3 minor isomer), 190.4 (br s; OCOCH3 minor
isomer), 190.3 (br s; OCOCH3 major isomer), 180.3 (br s; OCOCH3
1
3.51. H NMR (200.1 MHz, CDCl3, 20 °C): δ 7.34−6.97 (m, 30H;
3
aromatic protons), 5.31 (br s, 4H: NH2), 2.67 (br s, 4H; CH2N), 1.67
major isomer), 165.3 (d, J(C,P) = 1.6 Hz; NCCH2 minor isomer),
(s, 6H; OCOCH3). 31P{1H} NMR (81.0 MHz, CDCl3, 20 °C): δ
162.1 (d, 3J(C,P) = 1.4 Hz; NCCH2 major isomer), 160.7 (d, 3J(C,P)
= 2.3 Hz; NCH of C5H4N minor isomer), 151.4 (br s; NCH of
C5H4N major isomer), 138.9−121.7 (m; aromatic carbon atoms both
1
45.5 (s). H NMR (400.1 MHz, CD2Cl2, 25 °C): δ 7.42−7.23 (m,
3
18H; aromatic protons), 7.16 (t, J(H,H) = 7.4 Hz, 12H; aromatic
3
protons), 5.37 (br s, 4H; NH2), 2.70 (m, 4H; NCH2CH2N), 1.71 (s,
isomers), 53.6 (d, J(C,P) = 2.9 Hz; CH2N major isomer), 51.2 (d,
6H; OCOCH3). 13C{1H} NMR (100.6 MHz, CD2Cl2, 25 °C): δ
3J(C,P) = 2.3 Hz; CH2N minor isomer), 24.3 (br s; OCOCH3 major
1
4
182.7 (br s; OCOCH3), 136.0 (t, J(C,P) = 18.7 Hz; ipso-Ph), 135.6
isomer), 24.2 (m; OCOCH3 both isomers), 24.0 (d, J(C,P) = 1.5
(t, 1J(C,P) = 18.5 Hz; ipso-Ph), 134.2 (t, 2J(C,P) = 4.8 Hz; ortho-Ph),
128.8 (br s; para-Ph), 127.5 (t, 3J(C,P) = 4.4 Hz; meta-Ph), 43.9 (br
s; NCH2CH2N), 25.8 (br s; OCOCH3). 31P{1H} NMR (162.0 MHz,
CD2Cl2, 25 °C): δ 44.8 (s).
Hz; OCOCH3 minor isomer). 31P{1H} NMR (162.0 MHz, CD3OD,
25 °C): δ 65.3 (d, 2J(P,P) = 29.3 Hz; minor isomer), 60.6 (d, 2J(P,P)
= 32.6 Hz; major isomer), 49.4 (d, 2J(P,P) = 29.3 Hz; minor isomer),
2
47.4 (d, J(P,P) = 32.6 Hz; major isomer).
Synthesis of trans,cis-[Ru(κ1-OAc)2(PPh3)2(ampy)] (2). Meth-
od 1. Complex 2 was prepared by following the procedure used for
the synthesis of 1, with ampy (15.0 μL, 0.146 mmol, 1.09 equiv) in
place of en. Yield: 113 mg (99%). Anal. Calcd for C46H44N2O4P2Ru
(851.89): C, 64.86; H, 5.21; N, 3.29. Found: C, 64.90; H, 5.30; N,
Method 2. [Ru(κ1-OAc)2(PPh3)2](20 mg, 0.0269 mmol) and
ampy (3.0 μL, 0.0291 mmol, 1.08 equiv) were dissolved in CH3OH
(2 mL), and the mixture was stirred for 36 h at RT. The solvent was
evaporated under reduced pressure, and the residue was dissolved in
CH2Cl2 (0.5 mL). Addition of n-pentane (2 mL) afforded a yellow-
orange precipitate that was filtered, washed with n-pentane (3 × 2
mL), and dried under reduced pressure, leading to 2a,b in a 3:2 molar
ratio. Yield: 19 mg (83%).
1
3
3.31. H NMR (200.1 MHz, CD2Cl2, 20 °C): δ 8.45 (d, J(H,H) =
5.7 Hz, 1H; ortho-CH of C5H4N), 7.57−6.88 (m, 32H; aromatic
protons), 6.70 (br d, J(H,H) = 5.4 Hz, 2H; NH2), 6.53 (pseudo-t,
3
J(H,H) = 6.5 Hz, 1H; aromatic proton), 4.18 (m, 2H; CH2N), 1.67
Synthesis of trans,cis-[Ru(κ1-OAc)2(PPh3)2(ampyrim)] (3).
Complex 3 was prepared byfollowing the procedure used for the
synthesis of 1 (method 1), with ampyrim43 (16.1 μL, 0.168 mmol,
1.25 equiv) in place of en. Yield: 101 mg (88%). Anal. Calcd for
C45H43N3O4P2Ru (852.87): C, 63.37; H, 5.08; N, 4.93. Found: C,
63.45; H, 5.10; N, 4.91. 1H NMR (200.1 MHz, CDCl3, 20 °C): δ 8.49
(m, 1H; RuNCH of C4H3N2), 8.36 (m, 1H; NCH of C4H3N2), 7.48−
7.06 (m, 24H: aromatic protons), 7.05−6.88 (m, 6H: aromatic
protons), 6.48 (pseudo-t, J(H,H) = 5.1 Hz, 1H: aromatic proton),
6.22 (m, 2H; NH2), 4.31 (m, 2H; CH2N), 1.71 (s, 6H; OCOCH3).
13C{1H} NMR (50.3 MHz, CDCl3, 20 °C): δ 180.9 (br s; OCOCH3),
(s, 6H; OCOCH3). 13C{1H} NMR (50.3 MHz, CD2Cl2, 20 °C): δ
3
180.9 (d, 3J(C,P) = l.6 Hz; OCOCH3), 166.5 (dd, J(C,P) = 2.5 Hz,
3
3J(C,P) = 1.4 Hz; NCCH2), 156.7 (d, J(C,P) = 4.0 Hz; NCH of
C5H4N), 137.2−119.3 (m; aromatic carbon atoms), 51.6 (dd, 3J(C,P)
3
= 3.5 Hz, J(C,P) = 2.4 Hz; CH2N), 26.1 (s; OCOCH3). 31P{1H}
2
NMR (81.0 MHz, CD2Cl2, 20 °C): δ 44.6 (d, J(P,P) = 31.3 Hz),
2
39.4 (d, J(P,P) = 31.3 Hz).
Method 2. [Ru(κ1-OAc)2(PPh3)2] (37 mg, 0.050 mmol) and ampy
(6.0 μL, 0.058 mmol, 1.17 equiv) were dissolved in CD2Cl2 (0.45
mL). After 5 min at room temperature quantitative formation of 2 was
observed by NMR analysis.
3
3
176.3 (dd, J(CP) = 3.5 Hz, J(CP) = 1.4 Hz; NCCH2), 162.6 (d,
Method 3. [RuCl2(PPh3)3] (450 mg, 0.469 mmol) and NaOAc
(385 mg, 4.69 mmol, 10 equiv) were suspended in degassed acetone
(5 mL), and the mixture was refluxed for 3 h, affording a bright
orange precipitate of [Ru(κ2-OAc)2(PPh3)2]. When the reaction
mixture was cooled to room temperature, ampy (52 μL, 0.504 mmol,
1.07 equiv) was added and the mixture was stirred for 30 min, leading
to a bright yellow precipitate. After the addition of n-heptane (8 mL),
the solid was filtered, washed with water (3 × 10 mL), 2-propanol (1
mL), and n-pentane (3 × 5 mL), and dried under reduced pressure.
Yield: 303 mg (76%).
3J(CP) = 3.3 Hz; RuNCH of C4H3N2), 155.1 (s; NCH of C4H3N2),
3
136.3−117.6 (m; aromatic carbon atoms), 51.5 (t, J(CP) = 2.4 Hz;
CH2N), 25.9 (s; OCOCH3). 31P{1H} NMR (81.0 MHz, CDCl3, 20
2
2
°C): δ 43.6 (d, J(P,P) = 32.3 Hz), 39.7 (d, J(P,P) = 32.3 Hz).
Synthesis of cis-[Ru(κ2-OAc)(PPh3)2(ampyrim)]OAc (3a) and
cis,cis-[Ru(κ1-OAc)2(PPh3)2(ampyrim)] (3b). Complex 3 (27 mg,
0.032 mmol) was dissolved in CH3OH (2 mL), and the orange
solution was stirred for 48 h at RT. The solvent was evaporated under
reduced pressure, and the residue was dissolved in CH2Cl2 (0.5 mL).
Addition of n-pentane (2 mL) afforded a yellow-orange precipitate
that was filtered, washed with n-pentane (3 × 2 mL), and dried under
reduced pressure. The product consists of 3a,b in a 2:1 molar ratio.
Yield: 21 mg (78%). Anal. Calcd for C45H43N3O4P2Ru (852.87): C,
63.37; H, 5.08; N, 4.93. Found: C, 63.35; H, 5.14; N, 4.97. 1H NMR
Synthesis of cis-[Ru(κ2-OAc)(PPh3)2(ampy)]OAc (2a) and
cis,cis-[Ru(κ1-OAc)2(PPh3)2(ampy)] (2b). Method 1. Complex 2
(20 mg, 0.023 mmol) was dissolved in CH3OH (2 mL), and the
orange solution was stirred for 24 h at RT. The solvent was
evaporated under reduced pressure, and the residue was dissolved in
CH2Cl2 (0.5 mL). Addition of n-pentane (2 mL) gave a yellow-orange
precipitate, which was filtered, washed with n-pentane (3 × 2 mL),
and dried under reduced pressure. The product consists of 2a,b in a
3:2 molar ratio. Yield: 17 mg (85%). Anal. Calcd for
C46H44N2O4P2Ru (851.89): C, 64.86; H, 5.21; N, 3.29. Found: C,
3
(400.1 MHz, CD3OD, 25 °C): δ 8.82 (d, J(H,H) = 5.0 Hz, 1H;
RuNCH of C4H3N2 minor isomer), 8.66 (dd, 1H, 3J(H,H) = 4.9 Hz,
4J(H,H) = 2.1 Hz; RuNCH of C4H3N2 major isomer), 8.25 (dt,
4
3J(H,H) = 5.1 Hz, J(H,H) = 2.4 Hz, 1H; NCH of C4H3N2 major
isomer), 8.21 (dd, 3J(H,H) = 4.8 Hz, 4J(H,H) = 2.0 Hz, 1H; NCH of
3
1
C4H3N2 minor isomer), 7.61 (t, J(H,H) = 8.6 Hz, 4H; aromatic
64.80; H, 5.17; N, 3.37. H NMR (400.1 MHz, CD3OD, 25 °C): δ
8.20 (m, 1H; ortho-CH of C5H4N minor isomer), 7.98 (d, 3J(H,H) =
protons major isomer), 7.43−7.33 (m, 6H; aromatic protons both
3
isomers), 7.33−7.09 (m, 20H; aromatic protons both isomers), 7.06
5.7 Hz, 1H; ortho-CH of C5H4N major isomer), 7.73 (td, J(H,H) =
3
4
(t, J(H,H) = 5.4 Hz, 1H; aromatic proton major isomer), 7.03 (m,
7.7 Hz, J(H,H) = 1.8 Hz, 1H; para-CH of C5H4N major isomer),
3
1H; aromatic proton minor isomer), 6.90 (d, J(H,H) = 6.3 Hz, 1H;
7.70−7.63 (m, 3H; aromatic protons both isomers), 7.62−7.49 (m,
aromatic proton minor isomer), 5.98 (t, 3J(H,H) = 5.4 Hz, 1H;
aromatic proton minor isomer), 4.54−4.41 (m, 2H; CH2N minor
isomer), 4.17 (d, 2J(H,H) = 17.1 Hz, 1H; CH2N major isomer), 3.96
(d, 2J(H,H) = 17.1 Hz, 1H; CH2N major isomer), 1.91 (s, 3H;
OCOCH3 major isomer), 1.75 (s, 3H; OCOCH3 minor isomer), 1.36
(s, 3H; OCOCH3 minor isomer), 1.18 (s, 3H; OCOCH3 major
isomer). 13C{1H} NMR (100.6 MHz, CD3OD, 25 °C): δ 192.2 (d,
2J(C,P) = 2.1 Hz; OCOCH3 minor isomer), 190.9 (br s; OCOCH3
4H; aromatic protons both isomers), 7.48−7.08 (m, 22H; aromatic
3
protons both isomers), 6.96 (t, J(H,H) = 6.4 Hz, 1H; meta-CH of
3
C5H4N major isomer), 6.73 (d, J(H,H) = 6.0 Hz, 1H; meta-CH of
3
3
C5H4N minor isomer), 5.84 (ddd, J(H,H) = 7.6 Hz, J(H,H) = 5.8
4
Hz, J(H,H) = 1.6 Hz, 1H; meta-CH of C5H4N minor isomer), 4.48
(d, 2J(H,H) = 15.5 Hz, 1H; CH2N minor isomer), 4.42 (dd, 2J(H,H)
4
= 15.5 Hz, J(H,P) = 4.6 Hz, 1H; CH2N minor isomer), 4.10 (d,
2J(H,H) = 16.1 Hz, 1H; CH2N major isomer), 3.92 (d, J(H,H) =
2
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minor isomer), 190.8 (br s; OCOCH3 major isomer), 180.0 (br s;
OCOCH3 major isomer), 174.2 (d, 3J(C,P) = 1.6 Hz; NCCH2 minor
(br s; OCOCH3), 178.4 (br s; OCOCH3), 162.5 (s; NCCH2), 154.5
(s; NCH of C5H4N), 138.5−120.1 (m; aromatic carbon atoms), 50.9
3
3
(t, J(C,P) = 5.6 Hz; CH2N), 27.0 (m; PCH2), 23.9 (s; OCOCH3),
isomer), 172.2 (d, J(C,P) = 1.5 Hz; NCCH2 major isomer), 167.0
22.6 (s; OCOCH3). 31P{1H} NMR (162.0 MHz, CD3OD, 20 °C): δ
3
(d, J(C,P) = 1.5 Hz; RuNCH of C4H3N2 minor isomer), 158.7 (s;
2
2
21.1 (d, J(P,P) = 84.1 Hz), 7.4 (d, J(P,P) = 84.1 Hz).
RuNCH of C4H3N2 major isomer), 158.5 (s; NCH of C4H3N2 major
isomer), 156.4 (s; NCH of C4H3N2 minor isomer), 136.4−129.4 (m;
aromatic carbon atoms both isomers), 122.4 (d, J(C,P) = 1.5 Hz;
aromatic carbon atom major isomer), 120.4 (br s; aromatic carbon
atom minor isomer), 53.9 (d, 3J(C,P) = 2.0 Hz; CH2N major isomer),
Synthesis of trans-[Ru(κ1-OAc)2(dppf)(en)] (7). [Ru(κ2-
OAc)2(PPh3)2] (100 mg, 0.134 mmol) and dppf (75 mg, 0.135
mmol, 1.0 equiv) were dissolved in CH2Cl2 (1.5 mL) and stirred at
room temperature for 1 h. After addition of ethylenediamine (en) (13
μL, 0.195 mmol, 1.46 equiv), the solution was stirred at room
temperature for 30 min until a yellow precipitate was formed. n-
Pentane (3 mL) was added to the mixture, which was stirred for 30
min and filtered, giving a yellow compound, which was washed with n-
pentane (3 × 5 mL) and dried under reduced pressure. Yield: 101 mg
(90%). Anal. Calcd for C40H42FeN2O4P2Ru (833.65): C, 57.63; H,
3
4
51.7 (d, J(C,P) = 2.2 Hz; CH2N minor isomer), 24.3 (d, J(C,P) =
1.4 Hz; OCOCH3 minor isomer), 24.1 (br s; OCOCH3 both
isomers), 23.9 (d, 4J(C,P) = 1.3 Hz; OCOCH3 major isomer).
31P{1H} NMR (162.0 MHz, CD3OD, 25 °C): δ 64.3 (d, J(P,P) =
2
2
28.0 Hz; minor isomer), 58.8 (d, J(P,P) = 32.8 Hz; major isomer),
2
2
49.0 (d, J(P,P) = 28.0 Hz; minor isomer), 47.7 (d, J(P,P) = 32.8
Hz; major isomer).
1
5.08; N, 3.36. Found: C, 57.65; H, 5.14; N, 3.40. H NMR (200.1
Synthesis of trans-[Ru(κ1-OAc)2(dppm)2] (4). Complex 4 was
prepared by following a slight modification of a procedure described
for the synthesis of the cationic isomer [Ru(κ2-OAc)(dppm)2]OAc.32
[Ru(κ2-OAc)2(PPh3)2] (50.0 mg, 0.067 mmol) and dppm (51.9 mg,
0.135 mmol, 2.0 equiv) were stirred in toluene (0.75 mL) at 95 °C for
20 min. The solvent was evaporated under reduced pressure, and the
residue was added to n-heptane (4 mL). The mixture was stirred for
10 min, giving a suspension, which was filtered; the solid was washed
with n-heptane (2 × 1 mL) and n-pentane (2 × 1 mL) and dried
under reduced pressure. Yield: 45 mg (68%). Anal. Calcd for
C54H50O4P4Ru (987.96): C, 65.65; H, 5.10. Found: C, 65.70; H, 5.15.
1H NMR (200.1 MHz, CDCl3, 20 °C): δ 7.41−7.03 (m, 40H;
aromatic protons), 5.84 (m, 4H; PCH2), 0.80 (s, 6H; OCOCH3).
31P{1H} NMR (81.0 MHz, CDCl3, 20 °C): δ - 5.9 (s).
MHz, CD2Cl2, 20 °C): δ 7.69−7.55 (m, 8H; aromatic protons),
7.45−7.20 (m, 12H; aromatic protons), 4.92 (br s, 4H; NH2), 4.46
(m, 4H; C5H4), 4.24 (pseudo-t, J(H,H) = 1.8 Hz, 4H; C5H4), 2.64 (br
t, J(H,H) = 4.6 Hz, 4H; NCH2CH2N), 1.69 (s, 6H; OCOCH3).
13C{1H} NMR (50.3 MHz, CD2Cl2, 20 °C): δ 182.0 (t, 3J(C,P) = 1.0
Hz; OCOCH3), 138.0 (pseudo-t, J(C,P) = 18.3 Hz; ipso-Ph), 134.5 (t,
J(C,P) = 5.1 Hz; ortho-Ph), 129.3 (t, J(C,P) = 1.0 Hz; para-Ph),
127.7 (t, J(C,P) = 4.3 Hz; meta-Ph), 83.2 (pseudo-t, J(C,P) = 23.8 Hz;
3
ipso-C5H4), 75.1 (t, J(C,P) = 4.0 Hz; C5H4), 71.6 (t, J(C,P) = 2.8
Hz; C5H4), 43.9 (m; CH2N), 26.0 (s; OCOCH3). 31P{1H} NMR
(81.0 MHz, CD2Cl2, 20 °C): δ 48.3 (s).
Synthesis of trans-[Ru(κ1-OAc)2(dppp)(ampy)] (8). Method 1.
[Ru(κ2-OAc)2(PPh3)2] (100 mg, 0.134 mmol) and dppp (56.1 mg,
0.136 mmol, 1.01 equiv) were dissolved in CH2Cl2 (2 mL) and stirred
at room temperature for 1 h. ampy (20 μL, 0.194 mmol, 1.45 equiv)
was added to the mixture, and the resulting light orange solution was
stirred for 1 h at room temperature. The solvent was removed under
reduced pressure, n-pentane (5 mL) was added, and the suspension
was stirred for 10 min. After filtration, the yellow product was washed
with n-pentane (4 × 3 mL) and dried under reduced pressure. Yield:
84 mg (85%). Anal. Calcd for C37H40N2O4P2Ru (739.75): C, 60.07;
H, 5.45; N, 3.79. Found: C, 60.12; H, 5.44; N, 3.83. 1H NMR (200.1
MHz, CD2Cl2, 20 °C): δ 8.42 (d, 3J(H,H) = 4.8 Hz, 1H; ortho-CH of
C5H4N), 7.78−6.96 (m, 22H; aromatic protons), 6.71 (pseudo-t,
J(H,H) = 6.5 Hz, 1H; aromatic proton), 6.28 (br s, 2H; NH2), 4.12
(br m, 2H; CH2N), 2.62−2.35 (m, 4H; PCH2), 2.30−1.80 (m, 2H;
CH2), 1.68 (s, 6H; OCOCH3). 13C{1H} NMR (50.3 MHz, CD2Cl2,
20 °C): δ 180.9 (d, 3J(C,P) = 1.7 Hz; OCOCH3), 166.3 (dd, 3J(C,P)
Synthesis of trans-[Ru(κ1-OAc)2(dppe)2] (5). Complex 5 was
prepared by following the procedure used for the synthesis of 4, with
dppe (53.8 mg, 0.135 mmol, 2.0 equiv) in place of dppm. This
method presents some slight modifications in comparison to that
already reported for the synthesis of 5.32 Yield: 49 mg (72%). Anal.
Calcd for C56H54O4P4Ru (1016.01): C, 66.20; H, 5.36. Found: C,
1
66.26; H, 5.43. H NMR (200.1 MHz, CDCl3, 20 °C): δ 7.56−6.88
(m, 40H; aromatic protons), 3.20 (br m, 8H; PCH2CH2P), 0.80 (s,
6H; OCOCH3). 31P{1H} NMR (81.0 MHz, CDCl3, 20 °C): δ 44.7
(s).
Synthesis of cis-[Ru(κ1-OAc)2(dppm)(ampy)] (6). [Ru(κ2-
OAc)2(PPh3)2] (200 mg, 0.269 mmol) and dppm (104 mg, 0.270
mmol, 1.01 equiv) were dissolved in toluene (1 mL), and the mixture
was refluxed for 4 h, until the precursor was fully converted to [Ru(κ1-
OAc)2(dppm)(PPh3)] as verified by NMR analysis. ampy (31 μL,
0.300 mmol, 1.11 equiv) was added, and the solution was stirred at 95
°C for 14 h. The solvent was evaporated under reduced pressure, and
the residue was added to n-heptane (6 mL). The suspension was
stirred for 10 min, and the solid was filtered, washed with n-heptane
(2 × 2 mL) and n-pentane (2 × 2 mL), and dried under reduced
pressure. Yield: 145 mg (76%). Anal. Calcd for C35H36N2O4P2Ru
(711.70): C, 59.07; H, 5.10; N, 3.94. Found C, 59.15; H, 5.18; N,
3
3
= 2.7 Hz, J(C,P) = 1.4 Hz; NCCH2), 154.7 (dd, J(C,P) = 3.9 Hz,
3J(C,P) = 0.5 Hz; NCH of C5H4N), 138.6−119.7 (m; aromatic
carbon atoms), 50.5 (dd, 3J(C,P) = 3.6 Hz, 3J(C,P) = 2.0 Hz; CH2N),
27.4 (m; PCH2), 26.8 (m; PCH2), 25.2 (s; OCOCH3), 19.5 (dd,
2J(C,P) = 2.4 Hz, 2J(C,P) = 0.5 Hz; PCH2CH2). 31P{1H} NMR (81.0
MHz, CD2Cl2, 20 °C): δ 47.8 (d, 2J(P,P) = 49.1 Hz), 33.1 (d, 2J(P,P)
= 49.l Hz).
Method 2. [Ru(κ2-OAc)2(PPh3)2] (200 mg, 0.269 mmol) and
dppp (112 mg, 0.272 mmol) were suspended in acetone (2 mL) and
stirred for 3 h at room temperature. ampy (40 μL, 0.388 mmol, 1.44
equiv) was added, and the suspension was stirred for 1 h at room
temperature. The solid was filtered, washed with n-hexane (3 × 2
mL), and dried under reduced pressure. Yield: 185 mg (93%).
Method 3. trans,cis-[Ru(OAc)2(PPh3)2(ampy)] (2) (100 mg,
0.117 mmol) and dppp (49.5 mg, 0.120 mmol, 1.03 equiv) were
stirred in MEK (1 mL) at 50 °C for 20 h. The solution was
evaporated under reduced pressure, and the residue was added to n-
heptane (5 mL). The suspension was stirred for 10 min at room
temperature, and the solid was filtered, washed with n-heptane (2 × 3
mL) and n-pentane (2 × 2 mL), and dried under reduced pressure.
Yield: 53 mg (61%).
1
3.97. H NMR (200.1 MHz, CDCl3, 20 °C): δ 9.74 (m, 1H; NH2),
9.59 (m, 1H; ortho-CH of C5H4N), 8.01 (br t, 3J(H,H) = 8.1 Hz, 2H;
aromatic protons), 7.92−6.86 (m, 19H; aromatic protons), 6.70 (t,
3J(H,H) = 7.5 Hz, 2H; aromatic protons), 5.84 (pseudo-q, J(H,H) =
13.1 Hz, 1H; PCH2), 5.11 (m, 1H; PCH2), 3.58 (dd, 2J(H,H) = 16.1
3
Hz, J(H,H) = 5.0 Hz, 1H; CH2N), 3.32 (m, 1H; CH2N), 2.01 (s,
3H; OCOCH3), 1.58 (s, 3H; OCOCH3), 1.13 (m, 1H; NH2).
31P{1H} NMR (81.0 MHz, CDCl3, 20 °C): δ 23.4 (d, 2J(P,P) = 94.4
2
1
Hz), 7.9 (d, J(P,P) = 94.4 Hz). H NMR (400.1 MHz, CD3OD, 20
3
°C): δ 9.19 (m, 1H; ortho-CH of C5H4N), 7.81 (t, J(H,H) = 15.3
Hz, 2H; aromatic protons), 7.64 (br t, 3J(H,H) = 16.2 Hz, 1H;
aromatic proton), 7.51 (br t, 3J(H,H) = 13.6 Hz, 1H; aromatic
3
Synthesis of [Ru(κ2-OAc)(dppp)(ampy)]OAc (8a). Complex 8
(20 mg, 0.027 mmol) was dissolved in CH3OH (2 mL), and the
solution was stirred at room temperature for 56 h. The solvent was
evaporated under reduced pressure, and the residue was dissolved in
CH2Cl2 (0.5 mL). Addition of n-pentane (2 mL) afforded a yellow-
proton), 7.44−6.90 (m, 17H; aromatic protons), 6.68 (t, J(H,H) =
14.9 Hz, 2H; aromatic protons), 5.92 (m, 1H; PCH2), 5.33 (m, 1H;
PCH2), 3.61 (dd, 2J(H,H) = 16.2 Hz, 3J(H,H) = 5.6 Hz, 1H; CH2N),
2.35 (m, 1H; CH2N), 2.03 (s, 3H; OCOCH3), 1.66 (s, 3H;
OCOCH3). 13C{1H} NMR (100.6 MHz, CD3OD, 20 °C): δ 181.5
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4
orange precipitate, which was filtered, washed with n-pentane (3 × 2
mL), and dried under reduced pressure. Yield: 18 mg (90%). Anal.
Calcd for C37H40N2O4P2Ru (739.75): C, 60.07; H, 5.45; N, 3.79.
26.4 (br s; CH2), 24.7 (d; J(C,P) = 1.4 Hz; OCOCH3), 24.4 (s;
OCOCH3), 23.6 (br s; CH2). 31P{1H} NMR (162.0 MHz, CD3OD,
2
2
20 °C): δ 58.2 (d, J(P,P) = 37.2 Hz), 46.0 (d, J(P,P) = 37.2 Hz).
Synthesis of trans-[Ru(κ1-OAc)2(dppf)(ampy)] (10). Method
1. Complex 10 was prepared by following the procedure used for the
synthesis of 8 (method 1), with dppf (75 mg, 0.135 mmol, 1.01
equiv) in place of dppp. Yield: 87 mg (74%). Anal. Calcd for
C44H42FeN2O4P2Ru (881.69): C, 59.94; H, 4.80; N, 3.18. Found: C,
1
Found: C, 60.10; H, 5.47; N, 3.81. H NMR (400.1 MHz, CD3OD,
20 °C): δ 8.09 (d, 3J(H,H) = 5.7 Hz, 1H; ortho-CH of C5H4N), 7.82
3
(t, J(H,H) = 8.8 Hz, 2H; aromatic protons), 7.76−6.94 (m, 18H;
aromatic protons), 6.87 (t, 3J(H,H) = 6.8 Hz, 2H; aromatic protons),
6.80 (t, 3J(H,H) = 8.6 Hz, 1H; aromatic protons), 3.92 (d, 2J(H,H) =
16.9 Hz, 1H; CH2N), 3.29 (d, 2J(H,H) = 16.9 Hz, 1H; CH2N),
3.16−2.77 (m, 4H, PCH2), 2.74−2.35 (m, 2H, CH2), 1.92 (s, 3H;
CH3CO2), 1.52 (s, 3H; CH3CO2). 13C{1H} NMR (100.6 MHz,
CD3OD, 20 °C): δ 189.6 (d, 2J(C,P) = 2.8 Hz; OCOCH3), 180.4 (br
1
60.00; H, 4.85; N, 3.20. H NMR (200.1 MHz, CD2Cl2, 20 °C): δ
8.62 (d, 3J(H,H) = 3.1 Hz, 1H; ortho-CH of C5H4N), 7.81 (t,
3J(H,H) = 7.9 Hz, 3H; aromatic protons), 7.56 (t, 3J(H,H) = 8.8 Hz,
4H; aromatic protons), 7.49−6.92 (m, 15H; aromatic protons), 6.68
(pseudo-t, J(H,H) = 6.3 Hz, 1H; aromatic proton), 6.34 (pseudo-q,
J(H,H) = 5.7 Hz, 2H; NH2), 4.68 (br s, 2H; C5H4), 4.32 (br s, 2H;
C5H4), 4.15−3.88 (m, 6H; C5H4 and CH2N), 1.55 (s, 6H;
OCOCH3). 13C{1H} NMR (50.3 MHz, CD2Cl2, 20 °C): δ 181.2
(d, 3J(C,P) = 1.4 Hz, OCOCH3), 167.7 (dd, 3J(C,P) = 2.9 Hz,
3
s; OCOCH3), 162.9 (d, J(C,P) = 1.4 Hz; NCCH2), 149.9 (br s;
NCH of C5H4N), 139.0−122.2 (m; aromatic carbon atoms), 53.5 (d,
3J(C,P) = 3.0 Hz; CH2N), 29.8 (dd, 1J(C,P) = 31.7 Hz, 3J(C,P) = 2.7
1
3
Hz; PCH2), 29.6 (dd, J(C,P) = 30.3 Hz, J(C,P) = 2.7 Hz; PCH2),
24.8 (br s; OCOCH3), 24.4 (s; OCOCH3), 21.9 (t, J(C,P) = 1.9 Hz;
3J(C,P) = 1.6 Hz; NCCH2), 154.6 (d, J(C,P) = 3.2 Hz; NCH of
3
2
CH2). 31P{1H} NMR (162.0 MHz, CD3OD): δ 55.2 (d, J(P,P) =
2
48.4 Hz), 36.7 (d, J(P,P) = 48.4 Hz).
C5H4N), 136.6−120.1 (m; aromatic carbon atoms), 82.7 (dd, 1J(C,P)
= 43.7 Hz, 3J(C,P) = 4.0 Hz; ipso-C5H4), 81.4 (dd, 1J(C,P) = 47.3 Hz,
3J(C,P) = 2.2 Hz; ipso-C5H4), 75.5 (pseudo-t, J(C,P) = 8.0 Hz; C5H4),
72.9 (d, J(C,P) = 5.6 Hz; C5H4), 70.8 (d, J(C,P) = 4.5 Hz; C5H4),
50.7 (m; CH2N), 25.5 (s; OCOCH3). 31P{1H} NMR (81.0 MHz,
Synthesis of trans-[Ru(κ1-OAc)2(dppb)(ampy)] (9). Method 1.
Complex 9 was prepared by following the procedure used for the
synthesis of 8 (method 1), with dppb (57.8 mg, 0.136 mmol, 1.01
equiv) in place of dppp. Yield: 62 mg (61%). Anal. Calcd for
C38H42N2O4P2Ru (753.78): C, 60.55; H, 5.62; N, 3.72. Found: C,
2
2
CD2Cl2, 20 °C): δ 56.2 (d, J(P,P) = 37.8 Hz), 35.0 (d, J(P,P) =
1
60.50; H, 5.65; N, 3.70. H NMR (200.1 MHz, CD2Cl2, 20 °C): δ
37.8 Hz).
8.95 (m, 1H; ortho-CH of C5H4N), 7.83−7.08 (m, 22H; aromatic
Method 2. Complex 10 was prepared by following the procedure
used for the synthesis of 8 (method 2), with dppf (149 mg, 0.269
mmol, 1.0 equiv) in place of dppp. Yield: 209 mg (88%).
Method 3. Complex 10 was prepared by following the procedure
used for the synthesis of 8 (method 3), with dppf (66.5 mg, 0.120
mmol, 1.03 equiv) in place of dppp. Yield: 75 mg (73%).
3
protons), 6.81 (pseudo-t, J(H,H) = 6.6 Hz, 1H; aromatic proton),
6.03 (m, 2H; NH2), 4.06 (m, 2H; CH2N), 2.78 (m, 2H; PCH2), 2.25
(m, 2H; PCH2), 1.94−1.64 (m, 4H; PCH2CH2CH2), 1.53 (s, 6H;
OCOCH3). 13C{1H} NMR (50.3 MHz, CD2Cl2, 20 °C): δ 181.0 (d,
3J(C,P) = 1.5 Hz; OCOCH3), 167.5 (dd, 3J(C,P) = 2.9 Hz, 3J(C,P) =
1.4 Hz; NCCH2), 154.9 (d, J(C,P) = 3.7 Hz; NCH of C5H4N),
Synthesis of [Ru(κ2-OAc)(dppf)(ampy)]OAc (10a). Complex
10a was prepared by following the procedure used for the synthesis of
8a, employing trans-[Ru(κ1-OAc)2(dppf)(ampy)] (10) (20 mg,
0.0227 mmol) in place of 8. The solution of 10 in CH3OH was
stirred for 4 h at room temperature. Yield: 19 mg (95%). Anal. Calcd
for C44H42FeN2O4P2Ru (881.69): C, 59.94; H, 4.80; N, 3.18. Found:
C, 60.01; H, 4.84; N, 3.16. 1H NMR (400.1 MHz, CD3OD, 20 °C): δ
7.94 (d, 3J(H,H) = 5.7 Hz, 1H; ortho-CH of C5H4N), 7.82 (t,
3J(H,H) = 7.5 Hz, 1H; aromatic proton), 7.70−7.33 (m, 14H,
aromatic protons), 7.32−7.23 (m, 4H; aromatic protons), 7.15 (t,
3J(H,H) = 8.8 Hz, 2H; aromatic protons), 7.08 (t, 3J(H,H) = 6.7 Hz,
1H; aromatic proton), 4.55 (s, 1H; C5H4), 4.52 (s, 2H; C5H4), 4.43
(s, 1H; C5H4), 4.41 (s, 2H; C5H4), 4.38 (s, 1H; C5H4), 4.24 (s, 1H;
3
139.4−119.9 (m; aromatic carbon atoms), 50.6 (dd, J(C,P) = 3.8
Hz, 3J(C,P) = 2.0 Hz; CH2N), 33.9 (dd, 1J(C,P) = 27.1 Hz, 3J(C,P) =
3.0 Hz; PCH2), 27.7 (d, 1J(C,P) = 25.3 Hz; PCH2), 26.5 (m;
PCH2CH2), 25.1 (m; OCOCH3), 19.9 (m; PCH2CH2). 31P{1H}
2
NMR (81.0 MHz, CD2Cl2, 20 °C): δ 51.1 (d, J(P,P) = 36.6 Hz),
2
36.5 (d. J(P,P) = 36.6 Hz).
Method 2. Complex 9 was prepared by following the procedure
used for the synthesis of 8 (method 2), with dppb (115.6 mg, 0.271
mmol, 1.01 equiv) in place of dppp. Yield: 156 mg (77%).
Method 3. Complex 9 was prepared by following the procedure
used for the synthesis of 8 (method 3), with dppb (51.2 mg, 0.120
mmol, 1.03 equiv) in place of dppp. Yield: 62 mg (70%).
Synthesis of [Ru(κ2-OAc)(dppb)(ampy)]OAc (9a). Complex 9a
was prepared by following the procedure used for the synthesis of 8a,
employing trans-[Ru(κ1-OAc)2(dppb)(ampy)] (9) (20 mg, 0.0265
mmol) in place of 8. The solution of 9 in CH3OH was stirred for 48 h
at room temperature. Yield: 19.6 mg (98%). Anal. Calcd for
C38H42N2O4P2Ru (753.78): C, 60.55; H, 5.62; N, 3.72. Found: C,
C5H4), 3.91 (d, 2J(H,H) = 16.3 Hz, 1H; CH2N), 3.60 (d, J(H,H) =
2
16.3 Hz, 1H; CH2N), 1.92 (s, 3H; OCOCH3), 1.26 (s, 3H;
OCOCH3). 13C{1H} NMR (100.6 MHz, CD3OD, 20 °C): δ 190.8 (t,
2J(C,P) = 2.9 Hz; OCOCH3), 180.4 (s; OCOCH3), 162.4 (d, 3J(C,P)
= 1.5 Hz; NCCH2), 151.2 (br s; NCH of C5H4N), 139.2−122.3 (m;
1
3
aromatic carbon atoms), 80.6 (dd, J(C,P) = 55.0 Hz, J(C,P) = 3.6
1
Hz; ipso-C5H4), 78.5 (d, J(C,P) = 11.7 Hz; C5H4), 77.3 (dd, 2J(C,P)
60.60; H, 5.64; N, 3.76. H NMR (400.1 MHz, CD3OD, 20 °C): δ
3
3
1
8.26 (d, J(H,H) = 5.6 Hz, 1H; ortho-CH of C5H4N), 7.90 (ddd,
= 11.7 Hz, J(C,P) = 0.7 Hz; C5H4), 76.3 (dd, J(C,P) = 54.5 Hz,
3J(C,P) = 1.3 Hz; ipso-C5H4), 76.0 (d, J(C,P) = 15.3 Hz; C5H4), 75.9
(d, J(C,P) = 15.4 Hz; C5H4), 74.5 (pseudo-t, J(C,P) = 7.3 Hz; C5H4),
74.3 (d, J(C,P) = 7.3 Hz; C5H4), 74.0 (d, J(C,P) = 5.9 Hz; C5H4),
3J(H,H) = 9.6 Hz, 3J(H,H) = 7.9 Hz, 4J(H,H) = 1.6 Hz, 2H; aromatic
3
protons), 7.77 (m, 2H; aromatic protons), 7.67 (td, J(H,H) = 7.7
4
Hz, J(H,H) = 1.6 Hz, 1H; aromatic proton), 7.63−7.49 (m, 6H,
3
aromatic protons), 7.44−7.25 (m, 5H; aromatic protons), 7.22 (d,
53.1 (d, J(C,P) = 2.3 Hz; CH2N), 24.4 (s; OCOCH3), 24.3 (br s;
3
3J(H,H) = 8.0 Hz, 1H; aromatic proton), 7.15 (t, J(H,H) = 6.2 Hz,
OCOCH3). 31P{1H} NMR (162.0 MHz, CD3OD, 20 °C): δ 59.9 (d,
2J(P,P) = 35.3 Hz), 49.6 (d, J(P,P) = 35.3 Hz).
2
1H; aromatic proton), 7.06 (m, 1H; aromatic proton), 6.98 (td,
3J(H,H) = 7.9 Hz, 4J(H,H) = 1.6 Hz, 2H; aromatic protons), 6.87 (t,
Synthesis of trans-[Ru(κ1-OAc)2((R)-BINAP)(ampy)] (11).
[Ru(κ2-OAc)2(PPh3)2] (100 mg, 0.134 mmol) and (R)-BINAP (85
mg, 0.136 mmol, 1.01 equiv) were suspended in toluene (1.5 mL) and
refluxed for 24 h. The resulting orange solution was cooled to room
temperature, and ampy (20 μL, 0.194 mmol, 1.45 equiv) was added.
The light orange solution obtained was stirred for 1 h at room
temperature and the solvent removed under reduced pressure.
Treatment of the residue with n-pentane (10 mL) led to a suspension,
which was stirred for 10 min, and the yellow precipitate obtained was
filtered, washed with n-pentane (3 × 5 mL), and dried under reduced
pressure. Yield: 75.1 mg (59%). Anal. Calcd for C54H46N2O4P2Ru
2
3J(H,H) = 8.6 Hz, 2H; aromatic protons), 4.03 (d, J(H,H) = 16.4
Hz, 1H; CH2N), 3.60 (d, 2J(H,H) = 16.4 Hz, 1H; CH2N), 3.17−2.93
(m, 2H, PCH2), 2.46 (m, 1H; PCH2), 2.30 (m, 1H; PCH2), 2.20−
1.99 (m, 2H, CH2), 1.92 (s, 3H; CH3CO2), 1.80 (pseudo-q, J(H,H) =
13.6 Hz, 1H; CH2), 1.73−1.54 (m, 1H; CH2), 1.45 (s, 3H;
CH3CO2). 13C{1H} NMR (100.6 MHz, CD3OD, 20 °C): δ 189.7 (t,
2J(C,P) = 2.0 Hz; OCOCH3), 180.5 (s; OCOCH3), 162.0 (d, 3J(C,P)
= 1.5 Hz; NCCH2), 150.9 (s; NCH of C5H4N), 140.4−121.5 (m;
3
aromatic carbon atoms), 53.6 (d, J(C,P) = 2.9 Hz; CH2N), 31.3 (d,
1J(C,P) = 29.3 Hz; PCH2), 29.4 (pseudo-t, J(C,P) = 27.9 Hz; PCH2),
1096
https://doi.org/10.1021/acs.organomet.1c00059
Organometallics 2021, 40, 1086−1103

Organometallics
pubs.acs.org/Organometallics
Article
(949.99): C, 68.27; H, 4.88; N, 2.95. Found: C, 68.35; H, 4.85; N,
2H; CH2N), 2.59−2.44 (m, 4H; PCH2), 2.02−1.85 (m, 2H; CH2),
1
3.01. H NMR (400.1 MHz, CD2Cl2, 25 °C): δ 8.48 (m, 1H; ortho-
1.75 (s, 6H; OCOCH3). 13C{1H} NMR (100.6 MHz, CD2Cl2, 25
3
3
3
CH of C5H4N), 8.18 (t, J(H,H) = 8.1 Hz, 1H; aromatic proton),
°C): δ 182.3 (d, J(CP) = 2.2 Hz; OCOCH3), 177.8 (dd, J(CP) =
2.5 Hz, 3J(CP) = 1.3 Hz; NCCH2), 162.1 (d, 3J(CP) = 3.1 Hz;
RuNCH of C4H3N2), 157.4 (s; NCH of C4H3N2), 138.4 (d, 1J(CP) =
41.1 Hz; ipso aromatic carbon atoms), 134.9−128.7 (m; aromatic
carbon atoms), 119.8 (t, J(CP) = 1.5 Hz; aromatic carbon atom), 52.0
7.75−7.69 (m, 2H; aromatic protons), 7.65−7.26 (m, 16H; aromatic
protons), 7.25−7.18 (m, 4H; aromatic protons), 7.03−6.91 (m, 2H;
3
aromatic proton and NH2), 6.88 (t, J(H,H) = 8.0 Hz, 1H; aromatic
proton), 6.84−6.76 (m, 2H; aromatic protons), 6.72 (t, 3J(H,H) = 7.1
3
3
1
3
Hz, 2H; aromatic protons), 6.62 (t, J(H,H) = 6.5 Hz, 1H; aromatic
(t, J(CP) = 2.2 Hz; CH2N), 28.1 (dd, J(CP) = 30.1 Hz, J(CP) =
3
5.1 Hz; PCH2), 28.0 (d, 1J(CP) = 30.2 Hz; PCH2), 26.4 (s;
proton), 6.56 (d, J(H,H) = 8.6 Hz, 1H; aromatic proton), 6.43 (m,
3
OCOCH3), 20.7 (d, J(CP) = 2.2 Hz; CH2). 31P{1H} NMR (162.0
2
3H; aromatic protons), 6.26 (d, J(H,H) = 8.7 Hz, 1H; aromatic
proton), 5.06 (br q, 3J(H,H) = 6.6 Hz, 1H; NH2), 4.07 (dt, 2J(H,H) =
MHz, CD2Cl2, 25 °C): δ 47.9 (d, 2J(P,P) = 50.1 Hz), 32.6 (d, 2J(P,P)
= 50.1 Hz).
3
16.0 Hz, J(H,H) = 5.6 Hz, 1H; CH2N), 3.97 (m, 1H; CH2N), 1.83
(s, 3H; OCOCH3), 1.61 (s, 3H; OCOCH3). 13C{1H} NMR (100.6
Synthesis of [Ru(κ2-OAc)(dppp)(ampyrim)]OAc (12a). Com-
plex 12a was prepared by following the procedure used for the
synthesis of 8a, employing trans-[Ru(κ1-OAc)2(dppp)(ampyrim)]
(12) (23 mg, 0.0310 mmol) in place of 8. The solution of 12 in
CH3OH was stirred for 64 h at room temperature. Yield: 20 mg
(87%). Anal. Calcd for C36H39N3O4P2Ru (740.74): C, 58.37; H, 5.31;
3
MHz, CD2Cl2, 25 °C): δ 181.8 (d, J(C,P) = 1.5 Hz; OCOCH3),
181.3 (d, 3J(C,P) = 1.4 Hz; OCOCH3), 166.9 (dd, 3J(C,P) = 2.7 Hz,
3
3J(C,P) = 1.1 Hz; NCCH2), 155.5 (d, J(C,P) = 3.7 Hz; NCH of
C5H4N), 139.0−119.9 (m; aromatic carbon atoms), 50.6 (t, 3J(C,P) =
2.1 Hz; CH2N), 25.8 (br s; OCOCH3), 25.2 (br s; OCOCH3).
2
31P{1H} NMR (162.0 MHz, CD2Cl2, 25 °C): δ 54.9 (d, J(P,P) =
1
N, 5.67. Found: C, 58.32; H, 5.37; N, 5.63. H NMR (400.1 MHz,
2
3
4
36.9 Hz), 40.9 (d, J(P,P) = 36.9 Hz).
CD3OD, 25 °C): δ 8.93 (dd, J(H,H) = 4.8 Hz, J(H,H) = 2.9 Hz,
1H; RuNCH of C4H3N2), 8.47 (dd, 3J(H,H) = 4.8 Hz, 4J(H,H) = 1.9
Hz, 1H; NCH of C4H3N2), 7.88 (tt, 3J(H,H) = 8.5 Hz, 4J(H,H) = 1.3
Hz, 3H; aromatic protons), 7.74−7.63 (m, 5H; aromatic protons),
7.56−7.46 (m, 5H; aromatic protons), 7.43−6.97 (m, 7H; aromatic
protons), 6.81 (td, 3J(H,H) = 8.2 Hz, 4J(H,H) = 3.9 Hz, 1H; aromatic
proton), 4.30 (d, 2J(H,H) = 17.5 Hz, 1H; CH2N), 4.07 (d, 2J(H,H) =
17.5 Hz, 1H; CH2N), 3.12−2.99 (m, 4H; PCH2), 2.61−2.45 (m, 1H;
CH2), 2.40−2.22 (m, 1H; CH2), 1.92 (s, 3H; OCOCH3), 1.49 (s,
3H; OCOCH3). 13C{1H} NMR (100.6 MHz, CD3OD, 25 °C): δ
Synthesis of [Ru(κ2-OAc)((R)-BINAP)(ampy)]OAc (11a). Com-
plex 11a was prepared by following the procedure used for the
synthesis of 8a, employing trans-[Ru(κ1-OAc)2((R)-BINAP)(ampy)]
(11) (22 mg, 0.0232 mmol) in place of 8. The solution of 11 in
CH3OH was stirred for 18 h at room temperature. The product
consists of a 2:1 molar mixture of two stereoisomers. Yield: 21.1 mg
(96%). Anal. Calcd for C54H46N2O4P2Ru (949.99): C, 68.27; H, 4.88;
1
N, 2.95. Found: C, 68.32; H, 4.83; N, 2.99. H NMR (400.1 MHz,
3
CD3OD, 25 °C): δ 8.38 (d, J(H,H) = 2.9 Hz, 1H; ortho-CH of
3
2
C5H4N major isomer), 8.21 (d, J(H,H) = 3.9 Hz, 1H; ortho-CH of
190.3 (d, J(C,P) = 2.2 Hz; OCOCH3), 179.8 (br s; OCOCH3),
172.3 (d, 3J(C,P) = 1.4 Hz; NCCH2), 159.5 (s; RuNCH of C4H3N2),
158.0 (br s; NCH of C4H3N2), 137.7−128.8 (m; aromatic carbon
atoms), 121.1 (br s; aromatic carbon atom), 53.9 (t, 3J(C,P) = 1.4 Hz;
CH2N), 29.4 (dd, 1J(C,P) = 31.3 Hz, 3J(C,P) = 3.1 Hz; PCH2), 28.7
(d, 1J(C,P) = 34.5 Hz; PCH2), 24.5 (d, 4J(C,P) = 1.4 Hz; OCOCH3),
24.0 (br s; OCOCH3), 21.0 (br s; CH2). 31P{1H} NMR (162.0 MHz,
C5H4N minor isomer), 8.09−5.94 (m, 22H; aromatic protons both
isomers), 4.39 (d, 2J(H,H) = 16.2 Hz, 1H; CH2N major isomer), 4.16
(d, 2J(H,H) = 16.2 Hz, 1H; CH2N major isomer), 4.08 (d, 2J(H,H) =
16.4 Hz, 1H; CH2N minor isomer), 3.94 (d, 2J(H,H) = 16.4 Hz, 1H;
CH2N minor isomer), 1.92 (s, 3H; OCOCH3 minor and major
isomers), 1.50 (s, 3H; OCOCH3 major isomer), 1.41 (s, 3H;
OCOCH3 minor isomer). 13C{1H} NMR (100.6 MHz, CD3OD, 25
2
2
CD3OD, 25 °C): δ 56.1 (d, J(P,P) = 49.2 Hz), 37.7 (d, J(P,P) =
2
°C): δ 189.3 (d, J(C,P) = 2.4 Hz; OCOCH3 major isomer), 189.0
49.2 Hz).
2
(d, J(C,P) = 2.3 Hz; OCOCH3 minor isomer), 180.4 (s; OCOCH3
Synthesis of trans-[Ru(κ1-OAc)2(dppb)(ampyrim)] (13).
Method 1. Complex 13 was prepared by following the procedure
used for the synthesis of 12 (method 1), with dppb (58.5 mg, 0.137
mmol, 1.02 equiv) in place of dppp. Yield: 78.2 mg (77%).
Method 2. Complex 13 was prepared by following the procedure
used for the synthesis of 12 (method 2), with dppb (51.2 mg, 0.120
mmol, 1.03 equiv) in place of dppp. Yield: 66 mg (75%). Anal. Calcd
for C37H41N3O4P2Ru (754.77): C, 58.88; H, 5.48; N, 5.57. Found: C,
both isomers), 162.4 (br s; NCCH2 minor isomer), 162.1 (br s;
NCCH2 major isomer), 151.7 (br s; NCH of C5H4N minor isomer),
151.2 (br s; NCH of C5H4N major isomer), 143.0−122.2 (m;
3
aromatic carbon atoms both isomers), 53.1 (d, J(C,P) = 2.2 Hz;
CH2N major isomer), 52.4 (d, 3J(C,P) = 2.4 Hz; CH2N minor
isomer), 24.4 (br s; OCOCH3 major isomer), 24.2 (br s; OCOCH3
4
minor isomer), 23.9 (d; J(C,P) = 3.4 Hz; OCOCH3 minor isomer),
23.8 (br s; OCOCH3 major isomer). 31P{1H} NMR (162.0 MHz,
1
58.92; H, 5.41; N, 5.51. H NMR (400.1 MHz, CD2Cl2, 25 °C): δ
2
CD3OD, 25 °C): δ 68.3 (d, J(P,P) = 38.7 Hz; minor isomer), 61.1
9.00 (dt, 3J(H,H) = 5.8 Hz, 4J(H,H) = 2.9 Hz, 1H; RuNCH of
2
2
(d, J(P,P) = 38.8 Hz; major isomer), 58.1 (d, J(P,P) = 38.7 Hz;
3
4
C4H3N2), 8.56 (dd, J(H,H) = 4.8 Hz, J(H,H) = 2.2 Hz, 1H; NCH
of C4H3N2), 7.74−7.66 (m, 4H; aromatic protons), 7.48−7.31 (m,
12H; aromatic protons), 7.23 (ddd, 3J(H,H) = 9.1 Hz, 3J(H,H) = 7.1
Hz, 4J(H,H) = 2.0 Hz, 4H; aromatic protons), 6.84 (t, 3J(H,H) = 5.2
Hz, 1H; aromatic proton), 5.79 (pseudo-q, J(H,H) = 5.4 Hz, 2H;
2
minor isomer), 52.4 (d, J(P,P) = 38.8 Hz; major isomer).
Synthesis of trans-[Ru(κ1-OAc)2(dppp)(ampyrim)] (12).
Method 1. Complex 12 was prepared by following the procedure
used for the synthesis of 8 (method 1), with ampyrim (18.7 μL, 0.195
mmol, 1.45 equiv) in place of ampy. Yield: 82 mg (82%).
3
4
Method 2. trans,cis-[Ru(κ1-OAc)2(PPh3)2(ampyrim)] (3) (100
mg, 0.117 mmol) and dppp (49.5 mg, 0.120 mmol, 1.03 equiv) were
stirred in MEK (1 mL) at 50 °C for 18 h. The resulting solution was
evaporated under reduced pressure and the residue added to n-
heptane (5 mL). The suspension was stirred for 10 min and the solid
filtered, washed with n-heptane (2 × 3 mL) and n-pentane (2 × 2
mL), and dried under reduced pressure. Yield: 49 mg (57%). Anal.
Calcd for C36H39N3O4P2Ru (740.74): C, 58.37; H, 5.31; N, 5.67.
Found: C, 58.35; H, 5.35; N, 5.71. 1H NMR (400.1 MHz, CD2Cl2, 25
°C): δ 8.52 (dd, 3J(H,H) = 4.5 Hz, 4J(H,H) = 1.9 Hz, 1H; RuNCH of
C4H3N2), 8.41 (m, 1H; NCH of C4H3N2), 7.66 (t, 3J(H,H) = 8.0 Hz,
4H; aromatic protons), 7.47 (t, 3J(H,H) = 6.8 Hz, 2H; aromatic
NH2), 4.21 (td, J(H,H) = 6.3 Hz, J(H,H) = 2.8 Hz, 2H; CH2N),
3
3
2.83 (dt, J(H,H) = 10.0 Hz, J(H,H) = 6.3 Hz, 2H; PCH2), 2.30
3
3
4
(ddd, J(H,H) = 11.6 Hz, J(H,H) = 6.3 Hz, J(H,H) = 3.2 Hz, 2H;
PCH2), 1.90−1.78 (m, 2H; CH2), 1.76−1.63 (m, 2H, CH2), 1.61 (s,
6H; OCOCH3). 13C{1H} NMR (100.6 MHz, CD2Cl2, 25 °C): δ
3
3
182.3 (d, J(CP) = 1.5 Hz; OCOCH3), 178.6 (dd, J(CP) = 3.3 Hz,
3J(CP) = 1.4 Hz; NCCH2), 162.5 (d, J(CP) = 3.5 Hz; RuNCH of
3
1
C4H3N2), 157.5 (s; NCH of C4H3N2), 139.4 (d, J(CP) = 38.3 Hz;
ipso aromatic carbon atoms), 139.0 (d, 1J(CP) = 31.9 Hz; ipso
aromatic carbon atoms), 135.3−129.1 (m; aromatic carbon atoms),
3
119.9 (t, J(CP) = 1.4 Hz; aromatic carbon atom), 52.2 (t, J(CP) =
2.2 Hz; CH2N), 34.8 (dd, 1J(CP) = 27.3 Hz, 3J(CP) = 2.6 Hz;
1
3
PCH2), 28.5 (d, J(CP) = 25.0 Hz; PCH2), 27.7 (s; CH2), 26.4 (s;
protons), 7.43−7.30 (m, 8H; aromatic protons), 7.27 (t, J(H,H) =
OCOCH3), 21.0 (pseudo-t, J(CP) = 2.8 Hz; CH2). 31P{1H} NMR
(162.0 MHz, CD2Cl2, 25 °C): δ 50.0 (d, 2J(P,P) = 37.7 Hz), 36.6 (d,
2J(P,P) = 37.7 Hz).
7.1 Hz, 2H; aromatic protons), 7.12 (t, 3J(H,H) = 6.6 Hz, 4H;
3
aromatic protons), 6.74 (t, J(H,H) = 5.1 Hz, 1H; aromatic proton),
6,07 (br s, 2H; NH2), 4.28 (td, 3J(H,H) = 6.7 Hz, 4J(H,H) = 2.6 Hz,
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Article
Synthesis of [Ru(κ2-OAc)(dppb)(ampyrim)]OAc (13a). Com-
plex 13a was prepared by following the procedure used for the
synthesis of 8a, employing trans-[Ru(κ1-OAc)2(dppb)(ampyrim)]
(13) (25 mg, 0.0331 mmol) in place of 8. The solution of 13 in
CH3OH was stirred for 54 h at room temperature. Yield: 22 mg
(88%). Anal. Calcd for C37H41N3O4P2Ru (754.77): C, 58.88; H, 5.48;
CH2N), 1.91 (s, 3H; OCOCH3), 1.31 (s, 3H; OCOCH3). 13C{1H}
2
NMR (100.6 MHz, CD3OD, 25 °C): δ 191.4 (d, J(C,P) = 2.1 Hz;
OCOCH3), 180.4 (s; OCOCH3), 172.4 (d, 3J(C,P) = 1.5 Hz;
NCCH2), 158.9 (s; RuNCH of C4H3N2), 158.0 (s; NCH of C4H3N2),
138.5−129.0 (m; aromatic carbon atoms), 122.4 (d, J(C,P) = 2.2 Hz;
1
3
aromatic carbon atom), 80.0 (dd, J(C,P) = 55.7 Hz, J(C,P) = 2.9
Hz; ipso-C5H4), 78.7 (d, J(C,P) = 12.5 Hz; C5H4), 77.3 (d, 2J(C,P) =
9.5 Hz; C5H4), 76.1 (m; C5H4), 75.9 (dd, 1J(C,P) = 52.8 Hz, 3J(C,P)
= 2.7 Hz; ipso-C5H4), 75.1 (d, J(C,P) = 7.3 Hz; C5H4), 75.0 (d,
J(C,P) = 5.9 Hz; C5H4), 74.0 (d, J(C,P) = 6.6 Hz; C5H4), 73.9 (d,
J(C,P) = 5.9 Hz; C5H4), 53.7 (d, 3J(C,P) = 1.5 Hz; CH2N), 24.6 (d,
4J(C,P) = 1.4 Hz; OCOCH3), 24.4 (br s; OCOCH3). 31P{1H} NMR
(162.0 MHz, CD3OD, 25 °C): δ 59.8 (d, 2J(P,P) = 35.3 Hz), 47.6 (d,
2J(P,P) = 35.3 Hz).
1
N, 5.57. Found: C, 58.95; H, 5.44; N, 5.60. H NMR (400.1 MHz,
3
4
CD3OD, 25 °C): δ 8.57 (dd, J(H,H) = 3.4 Hz, J(H,H) = 1.4 Hz,
3
1H; RuNCH of C4H3N2), 8.49 (d, J(H,H) = 3.7 Hz, 1H; NCH of
3
C4H3N2), 8.00−7.84 (m, 3H; aromatic protons), 7.74 (t, J(H,H) =
8.6 Hz, 2H; aromatic protons), 7.67−7.48 (m, 5H; aromatic protons),
7.45−7.26 (m, 4H; aromatic protons), 7.21 (m, 2H; aromatic
3
protons), 7.13−7.00 (m, 2H; aromatic protons), 6.91 (t, J(H,H) =
8.2 Hz, 2H; aromatic protons), 6,67 (t, 3J(H,H) = 8.0 Hz, 1H;
2
Synthesis of trans-[Ru(κ1-OAc)2((R)-BINAP)(ampyrim)] (15).
[Ru(κ2-OAc)2(PPh3)2] (100 mg, 0.134 mmol) and (R)-BINAP (85
mg, 0.136 mmol, 1.01 equiv) were suspended in toluene (1.5 mL) and
refluxed for 24 h. The resulting orange solution was cooled to room
temperature and evaporated to dryness. The residue was dissolved in
acetone (2 mL), and ampyrim (18.7 μL, 0.195 mmol, 1.45 equiv) was
added. The dark orange solution obtained was stirred for 18 h at room
temperature and the solvent removed under reduced pressure.
Treatment of the residue with a n-pentane/diethyl ether mixture
(3/1; 5 mL) led to a suspension, which was stirred for 10 min. The
resulting yellow precipitate was filtered, washed with an n-pentane/
diethyl ether mixture (3/1; 4 × 5 mL) and then with n-pentane (2 ×
5 mL), and finally dried under reduced pressure. Yield: 80.3 mg
(63%). Anal. Calcd for C53H45N3O4P2Ru (950.98): C, 66.94; H, 4.77;
aromatic proton), 4.09 (d, J(H,H) = 16.8 Hz, 1H; CH2N), 3.65 (d,
2J(H,H) = 16.8 Hz, 1H; CH2N), 3.19−3.03 (m, 2H; PCH2), 2.60−
2.41 (m, 1H; PCH2), 2.33−2.23 (m, 1H; PCH2), 2.32−2.05 (m, 2H;
CH2), 1.95−1.78 (m, 1H, CH2), 1.91 (s, 3H; OCOCH3), 1.64 (m,
1H, CH2), 1.49 (s, 3H; OCOCH3). 13C{1H} NMR (100.6 MHz,
CD3OD, 25 °C): δ 190.2 (d, 2J(C,P) = 1.3 Hz; OCOCH3), 180.3 (s;
OCOCH3), 172.2 (dd, 3J(C,P) = 3.5 Hz, 3J(C,P) = 1.4 Hz; NCCH2),
158.7 (s; RuNCH of C4H3N2), 158.3 (s; NCH of C4H3N2), 139.9−
128.2 (m; aromatic carbon atoms), 122.0 (br s; aromatic carbon
atom), 53.9 (d, 3J(C,P) = 1.5 Hz; CH2N), 29.3 (d, 1J(C,P) = 26.3 Hz;
PCH2), 29.2 (d, 1J(C,P) = 30.3 Hz; PCH2), 26.6 (t, 3J(C,P) = 1.7 Hz;
CH2), 24.8 (d, 4J(C,P) = 1.4 Hz; OCOCH3), 24.3 (br s; OCOCH3),
23.4 (br s; CH2). 31P{1H} NMR (162.0 MHz, CD3OD, 25 °C): δ
2
2
57.5 (d, J(P,P) = 37.2 Hz), 46.0 (d, J(P,P) = 37.2 Hz).
Synthesis of trans-[Ru(κ1-OAc)2(dppf)(ampyrim)] (14). Meth-
od 1. Complex 14 was prepared by following the procedure used for
the synthesis of 12 (method 1), with dppf (76.0 mg, 0.137 mmol, 1.02
equiv) in place of dppp. Yield: 101 mg (85%).
1
N, 4.42. Found: C, 66.98; H, 4.82; N, 4.46. H NMR (400.1 MHz,
CD2Cl2, 25 °C): δ 8.72 (m, 1H; RuNCH of C4H3N2), 8.46 (m, 1H;
3
NCH of C4H3N2), 8.22 (t, J(H,H) = 8.1 Hz, 1H; aromatic proton),
7.70−7.55 (m, 6H; aromatic protons), 7.53−7.44 (m, 4H; aromatic
protons), 7.44−7.17 (m, 11H; aromatic protons), 7.06−6.88 (m, 4H;
aromatic protons), 6.79 (m, 1H; aromatic proton), 6.71 (t, 3J(H,H) =
6.8 Hz, 1H; aromatic proton), 6.61 (d, 3J(H,H) = 7.2 Hz, 2H;
aromatic protons), 6.43 (m, 2H; aromatic protons), 6.24 (d, 3J(H,H)
= 8.5 Hz, 1H; aromatic proton), 5.89 (br s, 1H; NH2), 5.34 (br s, 1H;
NH2 (overlapped with the solvent signal)), 4.21−4.04 (m, 2H;
CH2N), 1.84 (s, 3H; OCOCH3), 1.68 (s, 3H; OCOCH3). 13C{1H}
NMR (100.6 MHz, CD2Cl2, 25 °C): δ 182.7 (br s; OCOCH3), 182.6
(s; OCOCH3), 177.9 (d, 3J(C,P) = 3.8 Hz; NCCH2), 163.1 (d,
3J(C,P) = 2.9 Hz; RuNCH of C4H3N2), 157.2 (s; NCH of C4H3N2),
139.7−126.1 (m; aromatic carbon atoms), 119.5 (s; aromatic carbon
Method 2. Complex 14 was prepared by following the procedure
used for the synthesis of 12 (method 2), with dppf (66.5 mg, 0.120
mmol, 1.03 equiv) in place of dppp. The solution was heated at 50 °C
for 36 h instead of the usual 18 h. Yield: 83 mg (80%). Anal. Calcd for
C43H41FeN3O4P2Ru (882.68): C, 58.51; H, 4.68; N, 4.76. Found: C,
1
58.52; H, 4.71; N, 4.80. H NMR (400.1 MHz, CD2Cl2, 25 °C): δ
8.68 (d, 3J(H,H) = 5.8 Hz, 1H; RuNCH of C4H3N2), 8.55 (d,
3J(H,H) = 4.8 Hz, 1H; NCH of C4H3N2), 7.82−7.76 (m, 4H;
aromatic protons), 7.62 (t, 3J(H,H) = 8.8 Hz, 4H; aromatic protons),
3
7.53−7.24 (m, 12H; aromatic protons), 6.74 (t, J(H,H) = 5.4 Hz,
1H; aromatic proton), 6.05 (br s, 2H; NH2), 4.80 (br s, 2H; C5H4),
4.38 (s, 2H; C5H4), 4.23−4.09 (m, 4H; C5H4 and CH2N), 4.03 (s,
2H; C5H4), 1.63 (s, 6H; OCOCH3). 13C{1H} NMR (100.6 MHz,
CD2Cl2, 25 °C): δ 182.3 (d, 3J(CP) = 1.4 Hz; OCOCH3), 178.9 (dd,
3J(C,P) = 3.8 Hz, 3J(C,P) = 1.4 Hz; NCCH2), 162.2 (d, 3J(CP) = 2.2
Hz; RuNCH of C4H3N2), 157.7 (s; NCH of C4H3N2), 137.2−128.7
(m; aromatic carbon atoms), 119.8 (t, J(C,P) = 1.4 Hz; aromatic
3
atom), 52.1 (d, J(C,P) = 1.8 Hz; CH2N), 26.9 (s; OCOCH3), 26.5
(s; OCOCH3). 31P{1H} NMR (162.0 MHz, CD2Cl2, 25 °C): δ 53.7
2
2
(d, J(P,P) = 37.2 Hz), 41.9 (d, J(P,P) = 37.2 Hz).
Synthesis of [Ru(κ2-OAc)((R)-BINAP)(ampyrim)]OAc (15a).
Complex 15a was prepared by following the procedure used for the
synthesis of 8a, employing trans-[Ru(κ1-OAc)2((R)-BINAP)-
(ampyrim)] (15) (21 mg, 0.022 mmol) in place of 8. The solution
of 15 in CH3OH was stirred for 18 h at room temperature. The
product consists of a mixture of two stereoisomers in about a 1:1
ratio. Yield: 18 mg (86%). Anal. Calcd for C53H45N3O4P2Ru
(950.98): C, 66.94; H, 4.77; N, 4.42. Found: C, 66.90; H, 4.72; N,
4.37. 1H NMR (400.1 MHz, CD3OD, 25 °C): δ 8.94 (m, 1H;
RuNCH of C4H3N2 first isomer), 8.75 (m, 1H; RuNCH of C4H3N2
second isomer), 8.61 (m, 1H; NCH of C4H3N2 first isomer), 8.49
1
3
carbon atom), 83.4 (dd, J(C,P) = 44.4 Hz, J(C,P) = 4.0 Hz; ipso-
1
3
C5H4), 82.3 (dd, J(C,P) = 48.4 Hz, J(C,P) = 2.2 Hz; ipso-C5H4),
76.8 (d, J(C,P) = 8.1 Hz; C5H4), 76.7 (d, J(C,P) = 8.8 Hz; C5H4),
74.2 (d, J(C,P) = 5.9 Hz; C5H4), 72.2 (d, J(C,P) = 5.1 Hz), 52.3 (t,
3J(CP) = 1.5 Hz; CH2N), 26.8 (s; OCOCH3). 31P{1H} NMR (162.0
MHz, CD2Cl2, 25 °C): δ 55.3 (d, 2J(P,P) = 38.2 Hz), 35.2 (d, 2J(P,P)
= 38.2 Hz).
Synthesis of [Ru(κ2-OAc)(dppf)(ampyrim)]OAc (14a). Com-
plex 14a was prepared by following the procedure used for the
synthesis of 8a, employing trans-[Ru(κ1-OAc)2(dppf)(ampyrim)]
(14) (23 mg, 0.0261 mmol) in place of 8. The solution of 14 in
CH3OH was stirred for 4 h at room temperature. Yield: 22.5 mg
(98%). Anal. Calcd for C43H41FeN3O4P2Ru (882.68): C, 58.51; H,
3
4
(dd, J(H,H) = 4.3 Hz, J(H,H) = 1.3 Hz, 1H; NCH of C4H3N2
second isomer), 8.13−5.66 (m, 33H; aromatic protons both isomers),
4.63 (d, 2J(H,H) = 17.0 Hz, 1H; CH2N first isomer), 4.52 (dd,
4
2J(H,H) = 17.0 Hz, J(H,H) = 3.0 Hz, 1H; CH2N first isomer), 4.40
(d, 2J(H,H) = 17.7 Hz, 1H; CH2N second isomer), 4.07 (d, 2J(H,H)
= 17.7 Hz, 1H; CH2N second isomer), 1.92 (s, 3H; OCOCH3 both
isomers), 1.64 (s, 3H; OCOCH3 second isomer), 1.58 (s, 3H;
OCOCH3 first isomer). 13C{1H} NMR (100.6 MHz, CD3OD, 25
°C): δ 190.2 (d, 2J(C,P) = 2.9 Hz; OCOCH3 first isomer), 189.9 (d,
2J(C,P) = 2.3 Hz; OCOCH3 second isomer), 179.8 (br s; OCOCH3
both isomers), 172.8 (br s,; NCCH2 second isomer), 172.4 (br s,;
NCCH2 first isomer), 159.3 (s; RuNCH of C4H3N2 second isomer),
1
4.68; N, 4.76. Found: C, 58.56; H, 4.73; N, 4.74. H NMR (400.1
MHz, CD3OD, 25 °C): δ 8.71 (d, 3J(H,H) = 5.9 Hz, 1H; RuNCH of
3
C4H3N2), 8.09 (d, J(H,H) = 4.3 Hz, 1H; NCH of C4H3N2), 7.70−
7.57 (m, 6H, aromatic protons), 7.55−7.34 (m, 12H; aromatic
protons), 7.32−7.11 (m, 7H; aromatic protons), 4.66 (s, 1H; C5H4),
4.58−4.39 (m, 5H; C5H4), 4.37−4.26 (m, 2H; C5H4), 3.96 (d,
2
2J(H,H) = 17.2 Hz, 1H; CH2N), 3.51 (d, J(H,H) = 17.2 Hz, 1H;
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3
159.2 (s; RuNCH of C4H3N2 first isomer), 158.0 (s; NCH of C4H3N2
second isomer), 157.9 (s; NCH of C4H3N2 first isomer), 137.8−126.9
(m; aromatic carbon atoms both isomers), 122.2 (d, J(C,P) = 1.5 Hz;
aromatic carbon atom first isomer), 120.2 (s; aromatic carbon atom
3J(C,P) = 1.5 Hz; NCCH2), 156.5 (d, J(C,P) = 3.8 Hz; NCH of
C5H4N), 137.3−118.9 (m; aromatic carbon atoms), 50.9 (t, 3J(C,P) =
2.2 Hz; CH2N), 40.1 (s; C(CH3)3), 28.4 (s; C(CH3)3). 31P{1H}
NMR (81.0 MHz, CDCl3, 20 °C): δ 45.8 (d, 2J(P,P) = 31.5 Hz), 38.5
3
2
second isomer), 54.0 (d, J(C,P) = 1.5 Hz; CH2N second isomer),
(d, J(P,P) = 31.5 Hz).
51.4 (d, 3J(C,P) = 2.4 Hz; CH2N first isomer), 24.2 (d; 4J(C,P) = 2.0
Hz; OCOCH3 second isomer), 24.0 (br s; OCOCH3 both isomers),
23.9 (br s; OCOCH3 first isomer). 31P{1H} NMR (162.0 MHz,
CD3OD, 25 °C): δ 67.5 (d, 2J(P,P) = 37.2 Hz; first isomer), 59.9 (d,
Synthesis of [Ru(κ1-OAc)(CNNOMe)(PPh3)2] (19). The ligand
HCNNOMe (69.2 mg, 0.323 mmol, 1.2 equiv) and NEt3 (375 μL,
2.690 mmol, 10.0 equiv) were added to [Ru(κ2-OAc)2(PPh3)2] (200
mg, 0.269 mmol) in 2-propanol (2.5 mL), and the mixture was stirred
at reflux for 12 h. The dark yellow precipitate was filtered, washed
with n-pentane (5 × 3 mL), and dried under reduced pressure. Yield:
181 mg (75%). Anal. Calcd for C51H46N2O3P2Ru (897.96): C, 68.22;
H, 5.16; N, 3.12. Found: C, 68.18; H, 5.20; N, 3.10. 1H NMR (400.1
MHz, CD2Cl2, 25 °C): δ 8.86 (m, 1H; NH2), 7.68 (s, 1H; aromatic
proton), 7.64−7.04 (m, 24H; aromatic protons), 7.06−6.75 (m, 10H;
aromatic protons), 6.59 (d, 3J(H,H) = 6.7 Hz, 1H; aromatic proton),
2
2J(P,P) = 39.1 Hz; second isomer), 50.8 (d, J(P,P) = 37.2 Hz; first
2
isomer), 50.3 (d, J(P,P) = 39.1 Hz; second isomer).
Synthesis of trans-[Ru(κ1-OAc)2(dppb)(8-aminoquinoline)]
(16). [Ru(κ2-OAc)2(PPh3)2] (100 mg, 0.134 mmol) and dppb (58
mg, 0.136 mmol, 1.01 equiv) were dissolved in dichloromethane (1.5
mL) and stirred for 1 h at room temperature. 8-Aminoquinoline (28
mg, 0.194 mmol, 1.45 equiv) was added, and the resulting light
orange solution was stirred for 1 h at room temperature. The solvent
was removed under reduced pressure, and n-pentane (5 mL) was
added to the residue, leading to a suspension, which was stirred for 10
min at room temperature. The resulting yellow precipitate was
filtered, washed with n-pentane (3 × 5 mL), and dried under reduced
pressure. Yield: 95 mg (90%). Anal. Calcd for C41H42N2O4P2Ru
(789.81): C, 62.35; H, 5.36; N, 3.55. Found: C, 62.32; H, 5.40; N,
3.53. 1H NMR (400.1 MHz, CD2Cl2, 20 °C): δ 9.23 (t, 3J(H,H) = 4.1
3
2
6.47 (d, J(H,H) = 6.0 Hz, 1H; aromatic proton), 4.09 (dd, J(H,H)
= 17.3 Hz, 3J(H,H) = 6.0 Hz, 1H; CH2N), 3.53 (s, 3H; OCH3), 3.42
(m, 1H; CH2N), 1.92 (m, 1H; NH2), 1.09 (s, 3H; OCOCH3).
13C{1H} NMR (100.6 MHz, CD2Cl2, 25 °C): δ 185.5 (dd, 2J(C,P) =
2
14.3 Hz, J(C,P) = 8.4 Hz; CRu), 180.1 (br s; OCOCH3), 163.4 (s;
NCC), 160.1 (s; CCOCH3), 157.3 (s; NCCH2), 142.8−108.6 (m;
aromatic carbon atoms), 54.9 (s; CH3O), 51.0 ppm (d, 2J(C,P) = 2.2
Hz; CH2N), 25.1 (d; J(C,P) = 2.9 Hz; OCOCH3). 31P{1H} NMR
4
3
(162.0 MHz, CD2Cl2, 25 °C): δ 57.2 (d, 2J(P,P) = 33.3 Hz), 52.9 (d,
2J(P,P) = 33.3 Hz).
Hz, 1H; NCH of C9H6N), 8.24 (m, 2H; NH2), 8.14 (dd, J(H,H) =
8.3 Hz, 4J(H,H) = 1.4 Hz, 1H; aromatic proton), 7.74 (td, 3J(H,H) =
8.5 Hz, 4J(H,H) = 1.5 Hz, 3H; aromatic protons), 7.64 (d, 3J(H,H) =
8.3 Hz, 1H; aromatic proton), 7.52−7.14 (m, 20H; aromatic
protons), 7.02 (dd, 3J(H,H) = 8.3 Hz, 3J(H,H) = 5.0 Hz, 1H;
aromatic proton), 2.84 (m, 2H; PCH2), 2.26 (pseudo-t, J(H,H) = 7.1
Hz, 2H; PCH2), 2.04−1.52 (m, 4H; CH2), 1.37 (s, 6H; OCOCH3).
13C{1H} NMR (50.3 MHz, CD2Cl2, 20 °C): δ 181.3 (br s;
Synthesis of [Ru(κ1-OAc)(AMTP)(dppb)] (20). Method 1. The
ligand HAMTP (22 mg, 0.111 mmol, 1.06 equiv) and NEt3 (150 μL,
1.076 mmol, 10.2 equiv) were added to [Ru(κ2-OAc)2(dppb)] (68
mg, 0.105 mmol) in 2-propanol (1 mL), and the mixture was stirred
at reflux for 2 h. The solvent was removed under reduced pressure,
and the solid residue was washed with water (1 mL) and dried under
reduced pressure for 2−3 days. Yield: 70 mg (85%). Anal. Calcd for
C43H44N2O2P2Ru (783.85): C, 65.89; H, 5.66; N, 3.57. Found: C,
65.91; H, 5.60; N, 3.60. 1H NMR (200.1 MHz, toluene-d8, 20 °C): δ
8.65 (br s, 1H; NH2), 8.51 (t, 3J(H,H) = 9.1 Hz, 2H; aromatic
3
OCOCH3), 156.2 (d, J(C,P) = 3.9 Hz; NCH of C9H6N), 150.6−
1
121.3 (m; aromatic carbon atoms), 34.1 (dd, J(C,P) = 27.3 Hz,
3J(C,P) = 2.6 Hz; PCH2), 27.8 (d, 1J(C,P) = 24.7 Hz; PCH2), 26.9 (s;
PCH2CH2), 25.0 (s; OCOCH3), 19.3 (br s; PCH2CH2). 31P{1H}
2
3
NMR (81.0 MHz, CD2Cl2, 20 °C): δ 50.5 (d, J(P,P) = 36.7 Hz),
protons), 8.06 (s, 1H; aromatic proton), 7.96 (t, J(H,H) = 7.6 Hz,
2H; aromatic protons), 7.73−7.05 (m, 12H; aromatic protons), 6.96
(m, 4H; aromatic protons), 6.72 (t, J(H,H) = 7.1 Hz, 2H; aromatic
2
37.2 (d, J(P,P) = 36.7 Hz).
Synthesis of [Ru(κ2-OPiv)2(PPh3)2] (17). Compound 17 was
prepared by following a procedure different from that previously
described.44 [RuCl2(PPh3)3] (1.00 g, 1.043 mmol) and sodium
pivalate monohydrate (1.482 g, 10.43 mmol) were suspended in
degassed tert-butyl alcohol (20 mL), and the mixture was heated at 70
°C for 2 h until a yellow precipitate was formed. The reaction mixture
was cooled to room temperature, and diethyl ether (10 mL) was
added. The suspension was stirred at room temperature for 10 min.
The precipitate was filtered, washed with water (3 × 10 mL),
methanol (2 × 4 mL), and diethyl ether (3 × 5 mL), and finally dried
under reduced pressure, giving 17 as a pale orange powder. Yield: 650
mg (75%). Anal. Calcd for C46H48O4P2Ru (827.90): C, 66.74; H,
3
protons), 6.44 (d, J(H,H) = 6.0 Hz, 1H; aromatic protons), 6.32 (t,
2
J(H,H) = 7.6 Hz, 2H; aromatic protons), 4.12 (dd, J(H,H) = 15.0
Hz, 3J(H,H) = 4.0 Hz, 1H; CH2N), 3.49 (m, 1H; CH2N), 3.40−3.04
(m, 2H; PCH2), 2.35 (s, 3H; CH3), 2.20−1.40 (m, 5H; CH2), 1.92
(s, 3H; CH3CO), 1.22 (m, 1H; NH2), 1.14 (m, 1H; CH2). 31P{1H}
2
NMR (81.0 MHz, CD2Cl2, 20 °C): δ 60.8 (d, J(P,P) = 38.3 Hz),
44.6 (d, 2J(P,P) = 38.3 Hz). 31P{1H} NMR (81.0 MHz, toluene-d8, 20
2
2
°C): δ 60.7 (d, J(P,P) = 38.5 Hz), 44.5 (d, J(P,P) = 38.5 Hz).
Method 2. [Ru(κ2-OAc)2(PPh3)2] (100 mg, 0.134 mmol) and
dppb (58 mg, 0.136 mmol, 1.01 equiv) were suspended in 2-propanol
and refluxed for 1 h. The mixture was cooled to room temperature,
and the ligand HAMTP (28 mg, 0.141 mmol, 1.05 equiv) and NEt3
(187 μL, 1.341 mmol, 10 equiv) were added. The mixture was then
refluxed for a further 2 h. The solvent was removed under reduced
pressure, and the solid residue was washed with water (1.5 mL) and
dried under reduced pressure for 2−3 days. Yield: 48 mg (46%).
Synthesis of [Ru(κ1-OAc)(AMBQPh)(dppb)] (21). Method 1.
The ligand HAMBQPh (45.5 mg, 0.160 mmol, 1.03 equiv) and NEt3
(220 μL, 1.578 mmol, 10.2 equiv) were added to [Ru(κ2-
OAc)2(dppb)] (100 mg, 0.155 mmol) in 2-propanol (1 mL), and
the mixture was stirred at reflux for 3.5 h. The solvent was removed
under reduced pressure and the residue added to n-pentane (5 mL).
The suspension was stirred for 5 min, and the solid was filtered,
washed with n-pentane (2 × 3 mL), and dried under reduced
pressure. Yield: 80 mg (59%).
1
5.84. Found: C, 66.81; H, 5.86. H NMR (200.1 MHz, CDCl3, 20
°C): δ 7.33−7.19 (m, 6H; aromatic protons), 7.18−6.96 (m, 24H;
aromatic protons), 0.78 (s, 18H; C(CH3)3). 13C{1H} NMR (50.3
MHz, CDCl3, 20 °C): δ 195.2 (br s; OCOC(CH3)3), 135.6−127.2
(m; aromatic carbon atoms), 39.4 (s; C(CH3)3), 26.6 (br s;
C(CH3)3). 31P{1H} NMR (81.0 MHz, CDCl3, 20 °C): δ 64.0 (s).
Synthesis of trans,cis-[Ru(κ1-OPiv)2(PPh3)2(ampy)] (18). [Ru-
(κ2-OPiv)2(PPh3)2] (17) (50 mg, 0.0604 mmol) was dissolved in
chloroform (1 mL), and ampy (6.5 μL, 0.0631 mmol, 1.04 equiv) was
added. The solution was stirred for 10 min at room temperature.
Addition of n-pentane (5 mL) afforded an orange precipitate, which
was filtered, washed with n-pentane (3 × 2 mL), and dried under
reduced pressure. Yield: 48 mg (85%). Anal. Calcd for
C52H56N2O4P2Ru (936.05): C, 66.72; H, 6.03; N, 2.99. Found: C,
66.71; H, 6.06; N, 3.03. 1H NMR (200.1 MHz, CDCl3, 20 °C): δ 8.51
Method 2. [Ru(κ2-OAc)2(PPh3)2] (200 mg, 0.269 mmol) and
dppb (115.8 mg, 0.272 mmol, 1.01 equiv) were suspended in 2-
propanol (2.5 mL) and refluxed for 4 h. The mixture was cooled to
room temperature, and the ligand HAMBQPh (91.8 mg, 0.323 mmol,
1.20 equiv) and NEt3 (375 μL, 2.690 mmol, 10 equiv) were added.
The mixture was then refluxed for further 12 h. The obtained
3
(br d, J(H,H) = 4.4 Hz, 1H; ortho-CH of C5H4N), 7.60−6.80 (m,
34H; aromatic protons and NH2), 6.55 (pseudo-t, J(H,H) = 6.4 Hz,
1H; aromatic proton), 4.03 (br m, 2H; CH2N), 0.85 (s, 18H;
C(CH3)3). 13C{1H} NMR (50.3 MHz, CDCl3, 20 °C): δ 188.2 (d,
3J(C,P) = 1.4 Hz; OCOC(CH3)3), 166.5 (dd, 3J(C,P) = 2.7 Hz,
1099
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Article
suspension was cooled to room temperature and the orange solid was
filtered, washed with 2-propanol (2 mL), n-pentane (4 × 5 mL) and
dried under reduced pressure. Yield: 152 mg (65%). Anal. Calcd for
C50H46N2O2P2Ru (869.95): C, 69.03; H, 5.33; N, 3.22. Found: C,
NMR data of the isolated complexes and X-ray
crystallographic details of compound 7 (PDF)
Accession Codes
1
69.01; H, 5.36; N, 3.23. H NMR (200.1 MHz, CD2Cl2, 20 °C): δ
CCDC 2058063 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
data_request@ccdc.cam.ac.uk, or by contacting The Cam-
bridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
8.61 (m, 1H; NH2), 8.22 (pseudo-t, J(H,H) = 7.6 Hz, 2H; aromatic
3
protons), 7.91 (d, J(H,H) = 7.1 Hz, 1H; aromatic proton), 7.80−
7.15 (m, 21H; aromatic protons), 7.60 (d, 3J(H,H) = 8.5 Hz, 1H; H-5
benzo[h]quinoline), 6.96 (s, 1H; H-3 benzo[h]quinoline), 6.54 (t,
3
3J(H,H) = 7.4 Hz, 1H; aromatic proton), 6.22 (t, J(H,H) = 6.8 Hz,
2H; aromatic protons), 5.55 (t, 3J(H,H) = 8.4 Hz, 2H; aromatic
protons), 4.45 (dd, 2J(H,H) = 16.5 Hz, 3J(H,H) = 5.2 Hz, 1H;
CH2N), 3.97 (m, 1H; CH2N), 3.18 (m, 1H; PCH2), 2.86 (m, 1H;
PCH2), 2.50 (m, 2H; PCH2), 2.20−1.57 (m, 4H; CH2), 1.33 (s, 3H;
OCOCH3), 0.98 (m, 1H; NH2). 13C{1H} NMR (100.6 MHz,
CD2Cl2, 25 °C): δ 180.4 (br s; OCOCH3), 180.3 (dd, 2J(C,P) = 16.1
Hz, 2J(C,P) = 8.8 Hz; CRu), 157.5 (s; NCC), 152.7 (br s; NCCH2),
146.6−116.2 (m; aromatic carbon atoms), 52.5 (br s; CH2N), 31.1
AUTHOR INFORMATION
Corresponding Authors
■
̀
Maurizio Ballico − Dipartimento DI4A, Universita di Udine,
I-33100 Udine, Italy; orcid.org/0000-0001-6588-8037;
Email: maurizio.ballico@uniud.it
Walter Baratta − Dipartimento DI4A, Universita di Udine, I-
33100 Udine, Italy; orcid.org/0000-0002-2648-1848;
̀
1
3
1
(dd, J(C,P)= 24.9 Hz, J(C,P) = 1.5 Hz; CH2P), 30.7 (d, J(C,P) =
2
32.3 Hz; CH2P), 26.0 (d, J(C,P) = 1.5 Hz; CH2CH2P), 25.7 (d;
Email: walter.baratta@uniud.it
4J(C,P) = 3.8 Hz; OCOCH3), 22.0 (t, 2J(C,P) = 2.2 Hz; CH2CH2P).
31P{1H} NMR (162.0 MHz, CD2Cl2, 20 °C): δ 59.8 (d, J(P,P) =
2
Authors
2
37.9 Hz), 44.9 (d, J(P,P) = 37.9 Hz).
̀
Salvatore Baldino − Dipartimento DI4A, Universita di Udine,
Typical Procedure for TH of Ketones. The ruthenium catalyst
solution used for TH was prepared by dissolving the complexes 7−11,
16, and 21 (0.02 mmol) in 2-propanol (5 mL). The catalyst solution
(125 μL, 0.5 μmol) and a 0.1 M solution of NaOiPr (200 μL, 20
μmol) in 2-propanol were added subsequently to the carbonyl
compound solution (1.0 mmol) in 2-propanol (final volume 10 mL),
and the resulting mixture was heated under reflux. The reaction
mixture was sampled by removing an aliquot, which was quenched by
addition of diethyl ether (1/1 v/v), filtered over a short silica pad, and
submitted to GC analysis. The base addition was considered as the
start time of the reaction. The S/C molar ratio was 2000:1, whereas
the base concentration was 2 mol % with respect to the substrate (0.1
M). The same procedure was followed for TH reactions with other S/
C ratios (in the range 2000−10000), using the appropriate amount of
catalysts and 2-propanol.
̀
I-33100 Udine, Italy; Dipartimento di Chimica, Universita di
Torino, I-10125 Torino, Italy
̀
Steven Giboulot − Dipartimento DI4A, Universita di Udine,
I-33100 Udine, Italy; Johnson Matthey, Cambridge CB4
0FP, United Kingdom
̀
Denise Lovison − Dipartimento DI4A, Universita di Udine, I-
33100 Udine, Italy; orcid.org/0000-0002-1037-7384
Hans Gunter Nedden − Johnson Matthey, Cambridge CB4
̈
0FP, United Kingdom
Alexander Pöthig − Department of Chemistry & Catalysis
Research Center, TUM, 85747 Garching b. Munchen,
̈
Germany; orcid.org/0000-0003-4663-3949
Antonio Zanotti-Gerosa − Johnson Matthey, Cambridge CB4
0FP, United Kingdom
Typical Procedure for HY of Ketones and Aldehydes. The
HY reactions were performed in an eight-vessel Endeavor Biotage
apparatus. The vessels were charged with the catalysts 7, 9, 10, and 19
(5.0 μmol), loaded with 5 bar of N2, and slowly vented (five times).
The carbonyl compounds (5 mmol) and a KOtBu solution (1 mL, 0.1
mmol, 0.1 M) in methanol or ethanol were added. Further addition of
the solvent (methanol or ethanol) led to a 2 M carbonyl compound
solution. The vessels were purged with N2 and H2 (three times each),
and then the system was charged with H2 (20 or 30 bar) and heated
to 40 or 50 °C for the required time (16 h). The S/C molar ratio was
1000:1, whereas the base concentration was 2 mol %. A similar
method was applied for the reactions with other S/C ratios (in the
range 1000−10000), using the appropriate amount of catalysts and
solvent. The reaction vessels were then cooled to room temperature,
vented, and purged three times with N2. A drop of the reaction
mixture was diluted with 1 mL of methanol and analyzed by GC.
Single-Crystal X-ray Crystallographic Structure Determina-
tion of Compound 7. Single crystals of complex 7 were obtained by
slow cooling of a concentrated solution of the species in CH2Cl2. X-
ray diffraction data were collected with a Bruker kappa APEX-II CCD
diffractometer equipped with a rotating anode (Bruker AXS, FR591)
by using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å).
For additional details of the collection and refinement of data, see the
Supporting Information.
̀
Daniele Zuccaccia − Dipartimento DI4A, Universita di
Udine, I-33100 Udine, Italy; orcid.org/0000-0001-7765-
1715
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.organomet.1c00059
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
Dedicated to Prof. Christian Bruneau for his outstanding
contribution to catalysis. This work was supported by the
Ministero dell’Universita e della Ricerca (MIUR), PRIN 2015
program no. 20154 × 9ATP_005, the Fellowship Program
“Talents for an International House (TALENTS UP)”
(seventh R&D FP: PEOPLE-Marie Curie Actions-COFUND),
and the AREA Consortium of Trieste for a fellowship for S.G.
We thank Mr. Pierluigi Polese for the elemental analyses and
Dr. Paolo Martinuzzi for NMR assistance.
̀
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sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.organomet.1c00059.
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Article
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δ 62.2 (s). Relevant NMR data for cis-
[RuH(PPh3)2(CNNOMe)] are as follows. 1H NMR (400.1 MHz,
2
2
iPrOH/toluene-d8, 25 °C): δ −7.30 (dd, J(H,P) = 92.4 Hz, J(H,P)
1102
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Organometallics 2021, 40, 1086−1103

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Article
= 35.5 Hz). 31P{1H} NMR (162.0 MHz, iPrOH/toluene-d8, 25 °C): δ
2
2
68.8 (d, J(P,P) = 16.5 Hz), 33.9 (d, J(P,P) = 16.5 Hz).
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(43) ampyrim free base was obtained upon treatment of ampyrim·
HCl with aqueous KOH until the pH turned basic (litmus paper test)
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over Celite, drying with MgSO4, and further filtration. Dichloro-
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1103
https://doi.org/10.1021/acs.organomet.1c00059
Organometallics 2021, 40, 1086−1103