Ruthenium and rhodium complexes of thioether-alkynylborates

Article abstract of DOI:10.1021/om300075r

The species ((C₆F₅)₂BCH ₂SPh)₂ reacts with PhC≡CLi to give the thioether-alkynylborate (C₆F₅)₂BCH ₂SPh(C≡CPh)Li(THF)₂ (1). Subsequent reaction with (Ph₃P)₃RuHCl, (Ph₃P)₃RhCl, and [(COD)Rh(ν-Cl)]₂ gives (C₆F₅) ₂BCH₂SPh(C≡CPh)RuH(PPh₃)₂ (2), (C₆F₅)₂BCH₂SPh(C≡CPh) Rh(PPh₃)₂ (4), and (C₆F₅) ₂BCH₂SPh(C≡CPh)Rh(COD) (5), respectively, demonstrating a bidentate binding mode via the alkynyl and thioether donors of the borate. Subsequent reactions of 2 and 4 with H₂ gave (C ₆F₅)₂BCH₂SPh(CH₂CH ₂Ph)RuH(PPh₃)₂ (3) and ((C₆F ₅)₂BCH₂SPh(CHCHPh))Rh(PPh₃) ₂ (6). In the former case, the borate remains bound to the metal via a π-interaction with the thioether-arene ring, while in the latter case, S and alkene binding is observed.

Full text of DOI:10.1021/om300075r

Article
pubs.acs.org/Organometallics
Ruthenium and Rhodium Complexes of Thioether-Alkynylborates
Fatme Dahcheh and Douglas W. Stephan*
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
S
* Supporting Information
ABSTRACT: The species ((C6F5)2BCH2SPh)2 reacts with
PhCCLi to give the thioether-alkynylborate
(C6F5)2BCH2SPh(CCPh)Li(THF)2 (1). Subsequent reac-
tion with (Ph3P)3RuHCl, (Ph3P)3RhCl, and [(COD)Rh(μ-
Cl)]2 gives (C6F5)2BCH2SPh(CCPh)RuH(PPh3)2 (2),
(C6 F5 )2 BCH2 SPh(CCPh)Rh(PPh3 )2 (4), and
(C6F5)2BCH2SPh(CCPh)Rh(COD) (5), respectively, dem-
onstrating a bidentate binding mode via the alkynyl and thioether donors of the borate. Subsequent reactions of 2 and 4 with H2
gave (C6F5)2BCH2SPh(CH2CH2Ph)RuH(PPh3)2 (3) and ((C6F5)2BCH2SPh(CHCHPh))Rh(PPh3)2 (6). In the former case,
the borate remains bound to the metal via a π-interaction with the thioether-arene ring, while in the latter case, S and alkene
binding is observed.
derived from the related class of ligands polythioether borates,
[RB(CH2SR′)3]−, [RB(CH2SR′)2(pz)]−, and [R2B(CH2SR′)2]−
(Scheme 1), have been explored. On the other hand, borate
ligands with alkyl, vinyl, or aryl borate ligands have been
derived from reactions of donor-borane species with suitable
metal precursors, resulting in abstraction of metal-bound
fragments and the formation of chelating donor-borate
systems.48−52
In our own work, we have recently prepared the thioether-
borane species ((C6F5)2BCH2SPh)2 and shown that it is
capable of reacting with alkyne to generate B/S-based
heterocycles via frustrated Lewis pair (FLP) addition
reactions.53 In this paper, we explore the utility of this species
as a precursor to a thioether alkynyl-borate ligand. Herein, we
demonstrate that this ligand forms dissymmetric chelating
thioether alkynyl-borate complexes of Ru and Rh. Moreover,
these products react with H2 to give alkenyl and alkyl borates
while remaining bound to the corresponding metal centers.
INTRODUCTION
■
Polydentate B-based ligands have garnered much attention over
the past four decades. The quintessential example of such
ligands are tris(pyrazolyl)borates. Such ligands have been
popular for use in coordination chemistry, as a large range of
modifications altering the steric and electronic properties of
these ligands is conveniently achieved. Such chemistry has been
widely explored and extensively reviewed.1−21 Other borate-
based anionic ligands have garnered attention as well. For
example, Peters and co-workers have exploited monodentate,
bidentate, and tridentate borate-based ligands of the general
forms [R3BC6H4PR′2]−, [RB(CH2PR′2)3]−, and [R2B-
(CH2PR′2)2]− (Scheme 1) in a variety of creative develop-
Scheme 1. Examples of Homoleptic and Heteroleptic
Chelating Borate Ligands
RESULTS AND DISCUSSION
■
A solution of ((C6F5)2BCH2SPh)2 was reacted with lithium
phenylacetylide at −35 °C in THF. After the mixture was
stirred overnight with gradual warming to 25 °C, workup
afforded the white powder 1 in 85% yield (Scheme 2). The
11B{1H} NMR spectrum of 1 showed a sharp singlet at −18.32
ppm, while the 19F{1H} NMR spectrum showed multiplets at
−134.20, −161.63, and −165.95 ppm. These data are
ments.22−45 For example, these authors have developed unique
approaches to Fe hydrazine, CO2, and nitride chemistry,42,45,46
Cu aminyl radicals44 as well as novel routes to stabilize unusual
main-group species.23,32 Peters has also employed the
heteroleptic bis(phosphino)pyrazolylborate ligand [PhB-
(CH2PtBu2)2(pz)] to prepare terminal Fe(IV) imides.46
Related borate ligands with sulfur donors have been studied
and reviewed by Riodan and co-workers.47 In these cases, the
coordination chemistry and subsequent reactivity of complexes
1
consistent with the formation of a borate anion. H NMR
data were consistent with the presence of the thioether
fragment as well as an additional arene moiety, presumably
from the phenylacetylide. In addition, the NMR data support
the inclusion of 2 equivalents of THF in 1. These data were
consistent with the formulation of 1 as (C6F5)2BCH2SPh(C
Received: January 31, 2012
Published: March 23, 2012
© 2012 American Chemical Society
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some caution, as 1 sits on a crystallographic 2-fold symmetry
axis, resulting in crystallographic disorder of the methylene-
thioether and the alkyne fragments on the borate. Nonetheless,
these data affirm the nature of 1.
Scheme 2. Synthesis of 1−6
Reaction of 1 with (Ph3P)3RuHCl at room temperature gave
rise to a dark green solution on stirring overnight. Isolation of
the product 2 was achieved in 58% yield. The 11B{1H} and
19F{1H} NMR spectra of 2 gave resonances at −14.4 ppm and
−132.20, −162.18, and −165.87 ppm, respectively, consistent
with the presence of the borate anion. The 31P{1H} NMR
spectrum shows a sharp resonance at 64.6 ppm, consistent with
a single P environment. A 1H NMR resonance was observed at
−4.38 ppm, which is coupled to two P atoms with a coupling
constant of 28 Hz. These data confirm the formulation of 2 as
(C6F5)2BCH2SPh(CCPh)RuH(PPh3)2. The precise details
of the geometry of 2 were determined unambiguously via X-ray
diffraction (Figure 2). The Ru center of 2 adopts a pseudo-
CPh)Li(THF)2. This was subsequently confirmed crystallo-
graphically (Figure 1). The Li ion of 1 is coordinated to two
Figure 2. POV-ray depiction of 2: C, black; O, red; P, orange; S,
yellow; F, pink; B, yellow-green; Ru, light blue. Hydrogen atoms,
except for Ru−H, are omitted for clarity.
trigonal-bipyramidal geometry, with the hydride and thioether
linkage of the borate fragment occupying the axial positions.
The corresponding Ru−H and Ru−S distances were
determined to be 1.61(1) and 2.5013(9) Å, respectively. Two
phosphines complete the coordination sphere with Ru−P
distances of 2.248(1) and 2.294(1) Å. The alkynyl fragment of
the borate chelates to the metal in one of the equatorial plane
positions with Ru−C distances of 2.107(3) and 2.151(3) Å
with a CC bond length of 1.262(5) Å. The CC bond is
elongated compared to free alkynes (1.190 Å) and is similar to
that seen in the cation [Ru(acac)2(o-PhCC(C6H4)NMe2)]+
(1.224(6) Å) and [Ru(acac)2(o-PhCC(C6H4)NMe2)]+
(1.240(6) Å).54 The corresponding C−CC angle in 2 is
148.6(3)°, while the B−CC angle is 159.0(3)°. The former
“bend-back” angle of 31° is slightly larger than that seen for the
terminal phenyl ring on the alkyne of the Ru amine-alkyne
species cited above (25−26°).
Figure 1. POV-ray depiction of 1: C, black; O, red; S, yellow; F, pink;
B, yellow-green; Li, blue-green. Hydrogen atoms are omitted for
clarity. One conformation of the disordered thioether and alkynyl
fragments is shown.
The NMR data for 2 infer equivalent P atoms, while the
structural data affirm their inequivalence as a result of the
chirality at S. This suggests a fluxional process leads to
equilibration of the two P sites. This could occur via alkyne
dissociation or S inversion. Efforts to probe this fluxional
process by variable-temperature 31P NMR spectroscopy showed
broadening on cooling to −60 °C and the resolution of two
broad resonances at 76.4 and 56.6 ppm at −80 °C. As a limiting
THF molecules, the thioether sulfur, and (in a π fashion) to the
alkynyl unit on the borate. The Li−O distances were found to
be 1.878(7) Å, while the Li−S and Li−C distances were
2.530(6), 2.405(12), and 2.368(13) Å; the B−CC angle of
the alkynyl fragment was found to be 170.8(10)°. The
corresponding C−CC angle was determined to be
178.1(11)°. These metric parameters should be viewed with
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spectrum is not observed, the energetics of this fluxional
process could not be determined.
Exposure of 2 to 4 atm of H2 was performed at 25 °C and the
mixture stirred overnight. The solution changed color from
dark green to pale yellow, allowing the subsequent isolation of
pale yellow crystals of 3 in 96% yield. The presence of the
borate anion was consistent with the 11B{1H} resonance at
−11.5 ppm and the 19F{1H} multiplets at −131.86, −163.00,
1
and −165.68 ppm. H NMR data reveal the presence of new
methylene resonances at 3.05 and 2.28 ppm, while the
corresponding 13C{1H} resonances were observed at 34.7 and
29.4 ppm. In addition, the triplet resonance at 9.33 ppm in the
1H NMR spectrum as well as the 31P{1H} signal at 52.6 ppm
were consistent with the presence of RuH and two phosphine
ligands. These data suggest the formulation of 3 as a
combination of the saturated borate ligand and a RuH(PPh3)2
fragment. The observation of resonances at 5.08, 4.59, and 4.19
ppm are consistent with the presence of a η6-C6H5 fragment. X-
ray crystallography was used to confirm the formulation of 3 as
(C6F5)2BCH2SPh(CH2CH2Ph)RuH(PPh3)2 (Figure 3). These
Figure 4. Variable-temperature 31P{1H} NMR spectra of 4.
crystallographically (Figure 5). The pseudo-square-planar Rh
center is coordinated to S and P at distances of 2.3918(7),
Figure 3. POV-ray depiction of 3: C, black; O, red; P, orange; S,
yellow; F, pink; B, yellow-green; Ru, light blue. Hydrogen atoms are
omitted for clarity.
Figure 5. POV-ray depiction of 4: C, black; O, red; P, orange; S,
yellow; F, pink; B, yellow-green; Rh, maroon. Hydrogen atoms are
omitted for clarity.
data confirm the reduction of the alkyne fragment to the
corresponding alkyl group. The Ru adopts a “piano-stool” type
geometry with an η6 interaction with the S-bound arene ring of
the thioether-alkyl borate ligand. The Ru−C distances range
from 2.264(4) to 2.323(4) Å. Two phosphines are bound to Ru
at a distance of 2.308(1) and 2.313(1) Å. The third leg of the
piano stool is presumably the hydride; however, this was not
located in the electron density map. The geometry about B is,
as expected, pseudo-tetrahedral and the B center is positioned
5.723 Å from Ru.
2.2701(7), and 2.3133(7) Å. The alkynyl fragment is oriented
approximately perpendicular to the coordination plane of Rh
with Rh−C distances of 2.227(3) and 2.284(3) Å and a C−C
distance of 1.226(4) Å. The C−CC angle for the PhCC
fragment is 160.4(3)°, while the B−CC angle was found to
be 161.6(3)°. The corresponding bend-back angles are less
than those seen in 2, consistent with a more electron-rich Rh
center. A variable-temperature NMR study showed the
coalescence temperature to be 44 °C, and analysis of the
spectra revealed the activation energy for this fluxional process
to be 13.3(1) kcal/mol. These data suggest that facile exchange
of the phosphines occurs via dissociation of the alkyne,
followed by rotation and recoordination of the alkyne. An
alternative explanation could involve inversion at S. However,
this notion is deemed less likely, as the analogous alkene-borate
complex (C6F5)2BCH2SPh(CHCHPh))Rh(PPh3)2 (6) (vide
infra) is not fluxional.
The thioether-alkynylborate 1 also reacts with (Ph3P)3RhCl
in THF at room temperature, resulting in a dark orange
solution which on workup affords the yellow solid 4 in 94%
yield. The borate anion in the complex 4 is evident from the
11B{1H} resonance at −15.27 ppm and the corresponding
19F{1H} signals at −131.67, −161.80, and −165.46 ppm. At
room temperature the 31P{1H} NMR spectrum shows a broad
resonance at 35.3 ppm with Rh−P coupling of 153 Hz. On
cooling to −25 °C, the 31P{1H} NMR spectrum broadens and
splits into two doublets of doublets located at 42.4 and 29.2
ppm with P−P and Rh−P coupling constants of 41, 167, and
In a similar fashion, reaction of 1 with [(COD)Rh(μ-Cl)]2
affords the species (C6F5)2BCH2SPh(CCPh)Rh(COD) (5)
in 85% yield. The presence of the borate anion was consistent
with the11B{1H} resonance at −16.41 ppm and the 19F{1H}
1
162 Hz (Figure 4). These data together with the H NMR
1
resonances at −132.27, −159.68, and −164.25 ppm. The H
spectrum are consistent with the formulation of 4 as
(C6F5)2BCH2SPh(CCPh)Rh(PPh3)2. This was confirmed
NMR spectrum at room temperature shows a broad singlet at
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4.11 ppm corresponding to the olefinic COD protons, a broad
singlet at 1.57 ppm and a multiplet at 1.26 ppm arising from the
methylene COD protons. Upon cooling to −15 °C, each of the
two broad singlets split into two singlets at 4.19, 3.92, 1.64, and
1.45 ppm. These data suggest a fluxional process similar to that
in 4. The structure of 5 was confirmed crystallographically
(Figure 6). The pseudo-square-planar coordination geometry
Figure 7. POV-ray depiction of 6: C, black; O, red; P, orange; S,
yellow; F, pink; B, yellow-green; Rh, maroon. Hydrogen atoms are
omitted for clarity.
chelated olefin-thioether complex [(C5H7)2SRh-
(Ph2PCH2)2CH2]+ (Rh−S = 2.385(1) Å, Rh−C = 2.215(4),
2.230(4) Å) recently reported by Weller et al.55 In addition, the
Rh−S and Rh−C distances are somewhat shorter in 6 than in 4,
suggesting stronger binding of the thioether-alkenylborate
ligand.
CONCLUSIONS
Figure 6. POV-ray depiction of 5: C, black; O, red; S, yellow; F, pink;
B, yellow-green; Rh, maroon. Hydrogen atoms are omitted for clarity.
■
In this paper, we have demonstrated that the thioether alkynyl
borate 1 serves as a facile precursor to mixed donor borate
complexes of Ru and Rh. Moreover, these species are easily
reduced to convert the alkynyl fragment to either the
corresponding alkene or alkane moieties. Despite such
reductions of the alkynylborates, these anions remain bound
to the transition-metal center. We are continuing to study
transition-metal chemistry involving main-group-based ligand
systems.
about the Rh cation is comprised of the two olefinic bonds of
COD and the alkyne and S of 1. The Rh−C distances to the
COD ligand range from 2.148(2) to 2.183(2) Å, while the Rh−
C distances to the alkyne fragment are 2.269(2) and 2.306(2)
Å. The corresponding C−C bond distance is 1.226(3) Å, while
the CC−C and CC−B bend-back angles are 164.8(2) and
168.9(2)°, respectively. The Rh−S distance is 2.3833(6) Å,
slightly shorter than that seen in 4, consistent with the cationic
nature of 5.
EXPERIMENTAL SECTION
■
While reactions of 4 and 5 with H2 initially gave a complex
mixture of uncharacterized products ultimately leading to the
deposition of Rh black, reaction of 4 and Me2NH·BH3
proceeds at room temperature over 24 h to give dark orange
crystals of 6 in 69% yield. The 11B{1H} signal at −13.5 ppm
and the five 19F{1H} NMR signals at −131.45, −131.72,
−163.63, −163.73, and −166.98 ppm are indicative of the
presence of a borate anion with inequivalent C6F5 rings. The
31P{1H} NMR spectrum of 6 shows two resonances at 48.1 and
24.9 ppm which exhibit Rh−P couplings of 161 and 152 Hz,
respectively, and a P−P coupling of 36 Hz. This is consistent
General Remarks. All manipulations were carried out under an
atmosphere of dry, O2-free N2 employing an Innovative Technology
glovebox and a Schlenk vacuum line. Solvents were purified with a
Grubbs-type column system manufactured by Innovative Technology
and dispensed into thick-walled Schlenk glass flasks equipped with
Teflon-valve stopcocks (pentane, hexanes, toluene, THF, CH2Cl2) and
stored over molecular sieves. Deuterated solvents were dried over the
appropriate agents, vacuum-transferred into storage flasks with Teflon
stopcocks, and degassed accordingly (CD2Cl2, C6D6, Tol-d8). 1H, 13C,
11B, 19F, and 31P NMR spectra were recorded at 25 °C on Varian 300
and 400 MHz and Bruker 400 MHz spectrometers. Chemical shifts are
given relative to SiMe4 and referenced to the residual solvent signal
(1H, 13C) or relative to an external standard (31P, 85% H3PO4;11B,
(Et2O)BF3; 19F, CFCl3). In some instances, signal and/or coupling
assignment was derived from two-dimensional NMR experiments
(HSQC). In the case of the 19F NMR data for the fluoroarylboron
derivatives, the coupling constants given are only the apparent values
as these spectra exhibit second-order effects. Chemical shifts are
reported in ppm, and coupling constants as scalar values in Hz.
Combustion analyses were performed in-house, employing a Perkin-
Elmer CHN Analyzer.
1
with inequivalent P environments. H NMR data for 6 showed
the expected resonances in addition to resonances at 6.15 and
4.83 ppm. These signals in addition to the 13C{1H} signals at
108.4 and 91.4 ppm were consistent with the presence of an
olefinic fragment. These data lead to the formulation of 6 as
(C6F5)2BCH2SPh(CHCHPh))Rh(PPh3)2.
An X-ray structure of 6 confirmed a geometry similar to that
seen in 4, with the alkyne fragment reduced to the
corresponding alkene (Figure 7). It is noted that this reduction
led to a cis substitution of the alkene. The Rh−S, Rh−P, and
Rh−C distances in 6 were found to be 2.3648(5), 2.2737(6),
2.3700(6), 2.205(2), and 2.261(2) Å, respectively. The Rh−S
and Rh−C distances are similar to those reported seen in the
Synthesis of (C6F5)2BCH2SPh(CCPh)Li(THF)2 (1). A solution
of lithium phenylacetylide (0.032 g, 0.296 mmol) in 3 mL of THF was
added to a solution of (PhSCH2B(C6F5)2)2 (0.137 g, 0.146 mmol) in 3
mL of THF at −35 °C, and the solution was left stirring overnight
before the solvent was removed in vacuo and the white solid was
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1
washed with pentane, yielding a white powder (0.178 g, 85%). H
suspension of (PPh3)3RhCl (0.095 g, 0.103 mmol) in 5 mL of THF at
room temperature, and the mixture was stirred overnight. A dark
orange solution was obtained. The solvent was then removed in vacuo,
and the product was extracted into 10 mL of C6H6 and filtered over
Celite, resulting in an orange solution. The filtrate was concentrated to
1 mL, and pentane was added, resulting in a yellow solid which was
then collected on a frit and dried under vacuum (0.116 g, 94%). X-ray-
quality crystals were grown from benzene/pentane at 25 °C. 1H NMR
NMR (400 MHz, C64D6): δ 7.29 (m, 2H, C6H5), 7.23 (t, 4JH−H = 2 Hz,
3
1H, C6H5), 7.21 (t, JH−H = 1 Hz, 1H, C6H5), 6.99 (t, JH−H = 8 Hz,
4
2H, C6H5), 6.91 (m, 3H, C6H5), 6.88 (t, JH−H = 2 Hz, 1H, C6H5),
3.33 (s, 2H, BCH2S), 3.21 (m, 8H, THF-CH2(2,5)), 1.13 (m, 8H,
THF-CH2(3,4)) . 19F{1H} NMR (178 MHz, C6D6): δ −134.20 (dd,
3
3
4JF−F = 7 Hz, JF−F = 18 Hz, 4F, o-C6F5), −161.63 (t, JF−F = 21 Hz,
4
3
2F, p-C6F5), −165.95 (dt, JF−F = 7 Hz, JF−F = 22 Hz, 4F, m-C6F5).
13C{1H} NMR (101 MHz, C6D6, partial): δ 131.6 (C6H5), 128.9
(C6H5), 128.3 (C6H5), 127.3 (C6H5), 127.0 (C6H5), 126.1 (C6H5),
125.1 (C6H5), 68.3 (THF-CH2(2,5)), 27.8 (BCH2S), 25.05 (THF-
CH2(3,4)). 11B{1H} NMR (96 MHz, C6D6): δ −18.32 (sharp s). IR
(KBr) ν: 2155 cm−1 (CC). Anal. Calcd for C35H28BF10LiO2S: C,
58.35; H, 3.92. Found: C, 58.08; H, 4.02.
3
(400 MHz, C6D6): δ 7.62 (d, JH−H = 7 Hz, 2H, C6H5), 7.52 (br t,
3JH−H = 7 Hz, 1H, C6H5), 7.29 (t, 3JH−H = 8 Hz, 12H, PPh3), 6.98 (m,
4H, C6H5), 6.86−6.78 (overlapping t, 3JH−H = 7 Hz, 18H, PPh3), 6.69
3
3
(t, JH−H = 7 Hz, 1H, C6H5), 6.54 (t, JH−H = 7 Hz, 2H, C6H5), 3.37
(br s, 2H, BCH2S). 19F{1H} NMR (178 MHz, C6D6): δ −131.67 (d,
3JF−F = 23 Hz, 4F, o-C6F5), −161.80 (t, JF−F = 21 Hz, 2F, p-C6F5),
3
−165.46 (dt, 4JF−F = 9 Hz, 3JF−F = 21 Hz, 4F, m-C6F5). 31P{1H} NMR
Synthesis of (C6F5)2BCH2SPh(CCPh)RuH(PPh3)2 (2). A
solution of 1 (0.050 g, 0.069 mmol) in 3 mL of THF was added to
a suspension of (PPh3)3RuHCl (0.064 g, 0.069 mmol) in 5 mL of
THF at room temperature, and the mixture was stirred overnight. The
solvent was then removed in vacuo and the product extracted into 10
mL of CH2Cl2 and filtered over Celite, resulting in a dark green
solution. The filtrate was concentrated to 1 mL, and pentane was
added, resulting in a green-brown solid that was then collected on a frit
and dried under vacuum. The pentane layer was put in the freezer to
collect more of the product (0.048 g, 58%). X-ray-quality crystals were
grown from benzene/pentane at 25 °C. 1H NMR (400 MHz,
(161 MHz, C6D6): δ 35.3 (broad d, JP−Rh = 153 Hz). 31P{1H} NMR
1
1
2
(161 MHz, Tol-d8, −25 °C): δ 42.4 (dd, JP−Rh = 167 Hz, JP−P = 41
Hz, PPh3), 29.2 (dd, JP−Rh = 162 Hz, JP−P = 41 Hz, PPh3). 31P{1H}
1
2
1
NMR (161 MHz, Tol-d8, +50 °C): δ 35.1 (d, JP−Rh = 164 Hz,
PPh3).13C{1H} NMR partial (101 MHz, C6D6): δ 149.4 (m, Ar-F),
3
147.0 (m, Ar-F), 138.6, 137.9 (m, Ar-F), 134.7 (d, JC−P = 11 Hz,
PPh3), 133.7 (C6H5), 133.3 (C6H5), 133.08 (C6H5), 131.9 (d, JC−P
3
=
9 Hz, PPh3), 131.1 (PPh3), 129.4 (PPh3), 128.2 (C6H5), 127.0 (C6H5),
34.1 (BCH2S). 11B{1H} NMR (96 MHz, C6D6): δ −15.27 (sharp s).
IR (KBr) ν: 1961 cm−1 (CC). Anal. Calcd for C63H42BF10P2RhS: C,
63.23; H, 3.54. Found: C, 63.17; H, 3.73.
3
CD2Cl2): δ 7.72 (d, JH−H = 7 Hz, 2H, C63H5), 7.40 (m, 3H, C6H5),
3
Synthesis of (C6F5)2BCH2SPh(CCPh)Rh(COD) (5). A solution
of 1 (0.050 g, 0.070 mmol) in 3 mL of THF was added to a solution of
[RhCl(COD)]2 (0.017 g, 0.035 mmol) in 5 mL of THF at room
temperature and the mixture was stirred overnight. A pale orange
solution was obtained. The solvent was then removed in vacuo and the
product extracted into 6 mL of C6H6 and filtered over Celite, resulting
in a pale orange solution. The filtrate was concentrated to 1 mL, and
pentane was added, resulting in a yellow solid ,which was then
collected on a frit and dried under vacuum (0.046 g, 85%). X-ray-
quality crystals were grown from benzene/pentane at 25 °C. 1H NMR
(400 MHz, C6D6): δ 7.56 (m, 2H, C6H5), 7.49 (m, 2H, C6H5), 7.00
(m, 3H, C6H5), 6.95 (m, 3H, C6H5), 4.11 (br s, 4H, COD-CH), 3.11
(s, 2H, BCH2S), 1.57 (br s, 4H, COD-CH2), 1.26 (m, 4H, COD-
CH2). 1H NMR partial (400 MHz, Tol-d8, −15 °C): δ 4.19 (br s, 2H,
COD-CH), 3.92 (br s, 2H, COD-CH), 3.10 (s, 2H, BCH2S), 1.64 (br
s, 2H, COD-CH2), 1.45 (br s, 2H, COD-CH2), 1.22 (br s, 4H, COD-
CH2). 19F{1H} NMR (178 MHz, C6D6): δ −132.27 (d, 3JF−F = 22 Hz,
4F, o-C6F5), −159.68 (t, 3JF−F = 21 Hz, 2F, p-C6F5), −164.25 (dt, 4JF−F
= 9 Hz, 3JF−F = 21 Hz, 4F, m-C6F5). 13C{1H} NMR partial (101 MHz,
C6D6): δ 150.1 (m, Ar-F), 147.8 (m, Ar-F), 139.3, 137.7 (m, Ar-F),
133.3 (C6H5), 131.9 (C6H5), 129.9 (C6H5), 129.7 (C6H5), 129.3
(C6H5), 126.7 (C6H5), 93.6 (br s, COD-CH), 88.4 (br s, COD-CH),
34.8 (BCH2S), 31.2 (br s, COD-CH2), 29.9 (br s, COD-CH2).
11B{1H} NMR (96 MHz, C6D6): δ −16.41 (sharp s). Anal. Calcd. for
C35H24BF10RhS·Et2O: C, 54.82; H, 4.01. Found: C, 54.51; H, 3.69.
Synthesis of (C6F5)2BCH2SPh(CHCHPh)Rh(PPh3)2 (6). To a
solution of 4 (0.045 g, 0.038 mmol) in 3 mL of THF was added
Me2NH·BH3 (0.0023 g, 0.038 mmol), and the mixture was stirred at
room temperature for 24 h before the solvent was removed in vacuo;
the resulting residue was dissolved in 3 mL of Et2O and was left
overnight at 25 °C, upon which dark orange crystals formed. The
solvent was decanted, and the crystals were dried under vacuum (0.031
g, 69%). 1H NMR (400 MHz, CD2Cl2): δ 7.85 (d, 3JH−H = 6 Hz, 2H,
C6H5), 7.44 (m, 9H, PPh3), 7.35 (t, 3JH−H = 7 Hz, 3H, C6H5), 7.16 (m,
7.28 (t, JH−H = 7 Hz, 6H, PPh3), 7.16 (t, JH−H = 7 Hz, 1H, C6H5),
7.01 (t, 3JH−H = 7 Hz, 12H, PPh3), 6.82 (m, 14H, C6H5 + PPh3), 6.12
3
2
(d, JH−H = 8 Hz, 2H, C6H5), 3.34 (s, 2H, BCH2S), −4.38 (t, JH−P
=
28 Hz, 1H, Ru−H). 19F{1H} NMR (178 MHz, CD2Cl2): δ −132.20
(dd, JF−F = 9 Hz, JF−F = 24 Hz, 4F, o-C6F5), −162.18 (t, JF−F = 21
4
3
3
4
3
Hz, 2F, p-C6F5), −165.87 (dt, JF−F = 8 Hz, JF−F = 21 Hz, 4F, m-
C6F5). 31P{1H} NMR (161 MHz, CD2Cl2): δ 64.6 (s, PPh3). 31P{1H}
NMR (161 MHz, CD2Cl2, −80 °C): δ 76.4 (br s), 56.6 (br s).
13C{1H} NMR partial (101 MHz, CD2Cl2): δ 149.1 (m, Ar-F), 146.8
(m, Ar-F), 137.4 (m, Ar-F), 135.4 (C6H5), 134.9 (C6H5), 135.3 (d,
1JC−P = 43 Hz, Cipso, PPh3), 133.2 (t, JC−P = 5 Hz, o-C, PPh3), 131.9
2
(C6H5), 131.3 (C6H5), 129.7 (p-C, PPh3), 128.2 (C6H5), 127.9 (t,
2JC−P = 5 Hz, m-C, PPh3), 127.6 (C6H5), 34.07 (BCH2S). 11B{1H}
NMR (96 MHz, CD2Cl2): δ −14.4 (sharp s). IR (KBr) ν: 2088 cm−1
(CC). Anal. Calcd for C63H43BF10P2RuS: C, 63.27; H, 3.62. Found:
C, 63.34; H, 4.08.
Synthesis of (C6F5)2BCH2SPh(CH2CH2Ph)RuH(PPh3)2 (3). A
flask containing a solution of 2 (0.050 g, 0.042 mmol) in 5 mL of C6H6
was cooled to 77 K, evacuated, and filled with 1 atm of H2 and sealed.
Upon warming to 298 K, a pressure of ca. 4 atm was generated. The
reaction mixture was stirred at 25 °C overnight. A color change from
dark green to pale yellow was observed as pale yellow crystals
precipitated on standing overnight. The crystals were collected by
filtration, washed with pentane, and dried under vacuum (0.048 g,
96%). X-ray-quality crystals were grown from CH2Cl2/pentane at 25
°C. 1H NMR (400 MHz, C6D6): δ 7.57 (d, 3JH−H = 7 Hz, 2H, C6H5),
7.20 (t, 3JH−H = 7 Hz, 2H, C6H5), 7.13−7.18 (m, 15H, PPh3), 7.09 (m,
1H, C6H5), 6.88 (m, 15H, PPh3), 5.08 (t, 3JH−H = 6 Hz, 1H, η6-C6H5),
3
3
4.59 (d, JH−H = 6 Hz, 2H, η6-C6H5), 4.19 (t, JH−H = 6 Hz, 2H, η6-
C6H5), 3.35 (s, 2H, BCH2S), 3.05 (m, 2H, CH2CH2), 2.28 (m, 2H,
2
CH2CH2), −9.33 (t, JH−P = 28 Hz, 1H, Ru-H). 19F{1H} NMR (178
MHz, C6D6): δ −131.86 (dd, 4JF−F = 9 Hz, 3JF−F = 23 Hz, 4F, o-C6F5),
3
4
−163.00 (t, JF−F = 21 Hz, 2F, p-C6F5), −165.68 (dt, JF−F = 7 Hz,
3JF−F = 18 Hz, 4F, m-C6F5). 31P{1H} NMR (161 MHz, C6D6): δ 52.6
(s, PPh3). 13C{1H} NMR partial (101 MHz, CD2Cl2): δ149.2 (m, Ar-
F), 147.8 (m, Ar-F), 133.9 (PPh3), 132.4 (C6H5), 132.3 (C6H5), 130.5
(PPh3), 128.6 (C6H5), 128.4 (PPh3), 128.2 (C6H5), 98.9 (η6-C6H5),
90.8 (η6- C6H5), 87.8 (η6-C6H5), 34.7 (CH2CH2), 29.4 (BCH2S),
(CH2CH2). 11B{1H} NMR (96 MHz, C6D6): δ −11.5 (sharp s). Anal.
Calcd for C63H47BF10P2RuS: C, 63.06; H, 3.95. Found: C,62.62;
H,4.08.
3
9H, PPh3), 6.94 (m, 12H, PPh3), 6.77 (t, JH−H = 7 Hz, 1H, C6H5),
6.52 (t, 3JH−H = 8 Hz, 2H, C6H5), 6.15 (d, 2JH−Rh = 11 Hz, 1H, CH
CH), 5.21 (d, 3JH−H = 7 Hz, 2H, C6H5), 4.83 (d, 2JH−Rh = 11 Hz, 1H,
2
CHCH), 3.21 (br s, 1H, BCH2S), 2.75 (d, JH−H = 11 Hz, 1H,
3
BCH2S). 19F{1H} NMR (178 MHz, CD2Cl2): δ −131.45 (d, JF−F
=
22 Hz, 2F, o-C6F5), −131.72 (br s, 2F, o-C6F5), −163.63 (t, 3JF−F = 21
Hz, 1F, p-C6F5), −163.73 (t, 3JF−F = 21 Hz, 1F, p-C6F5), −166.98 (m,
1F, m-C62F5). 31P{1H} NMR (161 MHz, CD2Cl2): δ 48.1 (dd, 1JP−Rh
=
1
2
Synthesis of (C6F5)2BCH2SPh(CCPh)Rh(PPh3)2 (4). A solution
161 Hz, JP−P = 36 Hz, PPh3), 24.9 (dd, JP−Rh = 152 Hz, JP−P = 36
of 1 (0.075 g, 0.103 mmol) in 3 mL of THF was added to a stirred
Hz, PPh3). 13C{1H} NMR partial (101 MHz, CD2Cl2): δ 135.6 (d,
3226
dx.doi.org/10.1021/om300075r | Organometallics 2012, 31, 3222−3227

Organometallics
Article
3JC−P = 12 Hz, PPh3), 134.7 (d, 3JC−P = 12 Hz, PPh3), 133.2 (d, 2JC−P
=
(21) Guzman, E. C. Rev. R. Acad. Cienc. Exactas, Fis. Nat. Madrid
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(22) Peters, J. C.; Feldman, J. D.; Tilley, T. D. J. Am. Chem. Soc.
2
42 Hz, PPh3), 132.0 (PPh3), 131.9 (d, JC−P = 38 Hz, PPh3), 131.0
(PPh3), 130.6 (C6H5), 129.9 (C6H5), 128.4 (PPh3), 128.3 (PPh3),
128.1 (PPh3), 128.0 (PPh3), 127.7 (C6H5), 127.6 (C6H5), 127.2
(C6H5), 108.4 (CHCH), 91.4 (CHCH), 34.7 (BCH2S). 11B{1H}
NMR (96 MHz, CD2Cl2): δ −13.5 (sharp s). Anal. Calcd for
C63H44BF10P2RhS·C5H12: C, 64.26; H, 4.44. Found: C, 63.84; H, 4.58.
X-ray Data Collection, Reduction, Solution, and Refinement.
Single crystals were coated in Paratone-N oil in the glove-box,
mounted on a MiTegen Micromount and placed under an N2 stream.
The data were collected on a Bruker Apex II diffractometer. The data
were collected at 150( 2) K for all crystals. Data reduction was
performed using the SAINT software package, and an absorption
correction was applied using SADABS. The structures were solved by
direct methods using XS and refined by full-matrix least squares on F2
using XL as implemented in the SHELXTL suite of programs.56−58 All
non-hydrogen atoms were refined anisotropically. Carbon-bound
hydrogen atoms were placed in calculated positions using an
appropriate riding model and coupled isotropic temperature factors.
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(39) Li, J.; Djurovich, P. I.; Alleyne, B. D.; Yousufuddin, M.; Ho, N.
N.; Thomas, J. C.; Peters, J. C.; Bau, R.; Thompson, M. E. Inorg. Chem.
2005, 44, 1713.
(40) Lu, C. C.; Peters, J. C. Inorg. Chem. 2006, 45, 8597.
(41) Mehn, M. P.; Brown, S. D.; Paine, T. K.; Brennessel, W. W.;
Cramer, C. J.; Peters, J. C.; Que, L. Jr. Dalton Trans. 2006, 1347.
(42) Lu, C. C.; Saouma, C. T.; Day, M. W.; Peters, J. C. J. Am. Chem.
Soc. 2007, 129, 4.
(43) Mankad, N. P.; Peters, J. C. Chem. Commun. 2008, 1061.
(44) Mankad, N. P.; Antholine, W. E.; Szilagyi, R. K.; Peters, J. C. J.
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ASSOCIATED CONTENT
* Supporting Information
■
S
CIF files and a table giving crystallographic data for the
structures given in this paper. This material is available free of
charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: dstephan@chem.utoronto.ca.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
(45) Saouma, C. T.; Muller, P.; Peters, J. C. J. Am. Chem. Soc. 2009,
131, 10358.
(46) Thomas, C. M.; Mankad, N. P.; Peters, J. C. J. Am. Chem. Soc.
2006, 128, 4956.
The financial support of the NSERC of Canada is gratefully
acknowledged. D.W.S. is grateful for the award of a Canada
Research Chair.
(47) Riordan, C. G. Coord. Chem. Rev. 2010, 254, 1815.
(48) Fischbach, A.; Bazinet, P. R.; Waterman, R.; Tilley, T. D.
Organometallics 2008, 27, 1135.
(49) Kolpin, K. B.; Emslie, D. J. H. Angew. Chem., Int. Ed. 2010, 49,
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