The synthesis of an anionic, tetraphenylborate-functionalized, [P,N]-hybrid phosphinobenzimidazole ligand and its hemilabile behaviour in ruthenium zwitterion chemistry

Article abstract of DOI:10.1016/j.jorganchem.2014.03.003

A new anionic [P,N]-hybrid ligand based on a phosphinobenzimidazole scaffold and functionalized with a tetraphenylborate substituent is reported. This new anionic ligand readily chelates to a variety of ruthenium- cyclopentadienyl and -pentamethylcyclopentadienyl precursors to form a series of zwitterionic ruthenium piano-stool complexes (η⁵-C ₅R₅)Ru(L)(κ²-P,N) (R = H or Me; L = CO or PPh₃). In the presence of excess CO or 1-alkynes, the chelate complexes undergo ring-opening of the κ²-P,N ligand at the ruthenium-nitrogen bond (in some cases reversibly) under relatively mild conditions. In particular, the reactions with 1-alkynes proceed via vinylidene intermediates which subsequently insert into the ruthenium-nitrogen bond of the κ²-P,N ligand.

Full text of DOI:10.1016/j.jorganchem.2014.03.003

Accepted Manuscript
The Synthesis of an Anionic, Tetraphenylborate-Functionalized, [P,N]-Hybrid
Phosphinobenzimidazole Ligand and its Hemilabile Behaviour in Ruthenium
Zwitterion Chemistry
Jesse M. Walker, Joseph P. Tassone, Hilary A. Jenkins, Gregory J. Spivak
PII:
S0022-328X(14)00115-6
10.1016/j.jorganchem.2014.03.003
JOM 18506
DOI:
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 1 February 2014
Revised Date: 25 February 2014
Accepted Date: 1 March 2014
Please cite this article as: J.M. Walker, J.P. Tassone, H.A. Jenkins, G.J. Spivak, The Synthesis of
an Anionic, Tetraphenylborate-Functionalized, [P,N]-Hybrid Phosphinobenzimidazole Ligand and its
Hemilabile Behaviour in Ruthenium Zwitterion Chemistry, Journal of Organometallic Chemistry (2014),
doi: 10.1016/j.jorganchem.2014.03.003.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Table of contents entry and synopsis:
The Synthesis of an Anionic, Tetraphenylborate-Functionalized, [P,N]-Hybrid
Phosphinobenzimidazole Ligand and its Hemilabile Behaviour
in Ruthenium Zwitterion Chemistry
Jesse M. Walker,a Joseph P. Tassone,a Hilary A. Jenkinsb and Gregory J. Spivak*,a
aDepartment of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1;
email: greg.spivak@lakeheadu.ca
bMcMaster Analytical X-ray Diffraction Facility, McMaster University,
Hamilton, Ontario, Canada L8S 4M1
The synthesis of a new anionic [P,N]-hybrid ligand based on a phosphinobenzimidazole scaffold
and functionalized with a tetraphenylborate substituent is described. The coordination chemistry
and hemilability of this ligand when incorporated as an auxiliary ligand in zwitterionic
ruthenium piano-stool complexes are examined and discussed.

ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
The Synthesis of an Anionic, Tetraphenylborate-Functionalized, [P,N]-Hybrid
Phosphinobenzimidazole Ligand and its Hemilabile Behaviour
in Ruthenium Zwitterion Chemistry
Jesse M. Walker,a Joseph P. Tassone,a Hilary A. Jenkinsb and Gregory J. Spivak*,a
aDepartment of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1;
email: greg.spivak@lakeheadu.ca
bMcMaster Analytical X-ray Diffraction Facility, McMaster University,
Hamilton, Ontario, Canada L8S 4M1
Abstract
A new anionic [P,N]-hybrid ligand based on a phosphinobenzimidazole scaffold and
functionalized with a tetraphenylborate substituent is reported. This new anionic ligand readily
chelates to a variety of ruthenium-cyclopentadienyl and -pentamethylcyclopentadienyl precursors
to form a series of zwitterionic ruthenium piano-stool complexes (η5-C5R5)Ru(L)(κ2-P,N) (R = H
or Me; L = CO or PPh3). In the presence of excess CO or 1-alkynes, the chelate complexes undergo
ring-opening of the κ2-P,N ligand at the ruthenium-nitrogen bond (in some cases reversibly) under
relatively mild conditions. In particular, the reactions with 1-alkynes proceed via vinylidene
intermediates which subsequently insert into the ruthenium-nitrogen bond of the κ2-P,N ligand.
Keywords: ruthenium; zwitterionic; anionic phosphines; hybrid ligands; hemilabile; vinylidenes

ACCEPTED MANUSCRIPT
Introduction
The continued expansion of anionic organophosphorus ligands in transition metal
chemistry is linked, in part, to an increasing interest in investigating the impact of these phosphine
ligands in applications which customarily employ conventional neutral phosphines. Several
classes of anionic phosphine ligands employ a covalently bound borate group (either as a structural
unit or as a pendant group) as a way of rendering the phosphine ligand anionic.1-9 Interestingly,
some of the anionic phosphine ligands modified in this way reportedly display enhanced donor
powers over their neutral counterparts.1-3,5e,7i,10 The anionic nature of these phosphines also allows
access to the synthesis of zwitterionic complexes, and some zwitterionic catalysts have proven to
be differently (sometimes more) reactive or selective than their cationic counterparts in a number
of instances.8,11 We recently reported on the synthesis of anionic and zwitterionic complexes of
ruthenium containing the tetraphenylborate-modified monodentate phosphine ligands
[E][PR2(p-Ph3BC6H4)] (E = Bu4N+ or PNP+) which contain, at least conceptually, a
non-coordinating tetraphenylborate anion covalently tethered to a –PR2 unit.12 We have since
wondered if this strategy could be expanded to include bidentate ligands,8 especially
heterobidentate hybrid ligands possessing hemilabile13 properties. Thus, the key design features of
these ligands should include a substitutionally inert anchor donor group, a substitutionally labile
group, and a covalently tethered tetraphenylborate group, the latter of which would render the
ligand negatively charged.
We report here on the synthesis of the tetraphenylborate-functionalized, heterobidentate
phosphinobenzimidazole ligand 1 (Structure I). Ligand 1 readily chelates to ruthenium, but will
ring-open at the ruthenium nitrogen-bond in the presence of various substrates. The contrasting
pairing of the harder imidazole nitrogen with a comparatively softer ruthenium centre likely

ACCEPTED MANUSCRIPT
promotes hemilability. Furthermore, as a bidentate ligand, the relative positions of the phosphino
group and the imidazole nitrogen produce a strained bite angle, a feature that undoubtedly also
favours ring-opening of the metallacycle.
Results and Discussion
Synthesis and Characterization of Ligand 1. The anionic P,N-hybrid ligand 1
(abbreviated as [Li(THF)2][PPhNBPh4]) was prepared as illustrated in Scheme 1.14 During the
early stages of development, we initially attempted to use imidazole as a simpler building block;
however, the subsequent phosphination step of the 1-(4-bromobenzyl)imidazole15 precursor was
complicated by reactions also occurring at the 4- and 5-positions of the imidazole backbone at the
expense of the desired 2-position.16 Alternatively, employing benzimidazole allowed us to
circumvent these issues. Strict attention to reaction temperature, time and base was required for the
synthesis of the precursor 1-(4-bromobenzyl)-2-(diphenylphosphino)benzimidazole from
1-(4-bromobenzyl)benzimidazole15 and chlorodiphenylphosphine, otherwise
tetraphenyldiphosphine monoxide17 was observed to form as a by-product after work-up.
Similarly, the final step in the synthesis of 1 from
1-(4-bromobenzyl)-2-(diphenylphosphino)benzimidazole also required special consideration. The

ACCEPTED MANUSCRIPT
metalating agents n-BuLi, i-PrMgCl and i-PrMgClΧLiCl18 proved to be less effective than t-BuLi
for the borane addition reaction. Furthermore, careful control of the reaction temperature, time and
rate of addition of the BPh3 to the metalated intermediate was required, since otherwise
Li(t-BuBPh3)19 or the N-addition product20 would contaminate the desired product. Typically,
ligand 1 was isolated in 70-80% yields in this final step, and was sufficiently pure for further use.
The 31P{1H} NMR spectrum of 1 displays a sharp singlet at δ -24.1 ppm, while the 1H NMR
spectrum reveals that two equivalents of THF are retained in the product. The 11B NMR chemical
shift for ligand 1 appears at δ -6.7 ppm, which is similar to that observed for NaBPh4 (δ -6.2
ppm).21 The Ph4P+ salt of ligand 1 can easily be prepared via cation metathesis using Ph4PX (X =
Cl or Br) in CH2Cl2. The 31P chemical shift of the anion of [Ph4P][PPhNBPh4] appears further
upfield (δ -28.1 ppm) of that observed for 1, suggesting that in the latter case the anion
[PPhNBPh4]- chelates to the [Li(THF)2]+ cation in solution. Indeed, the 7Li NMR spectrum of 1 in
CDCl3 shows a sharp singlet at δ -0.35 ppm, and appears in a region observed for other similar
systems;22 at lower temperatures, however, this signal only broadens, and unfortunately no distinct
coupling to phosphorus is observed. For synthetic applications involving transition metal
precursors, the lithium salt is preferred as it assists in avoiding any issues which may arise
involving the removal of a Ph4P+ salt that might be produced as a reaction by-product.
Reactions of Ligand 1 with Ruthenium Piano-Stool Precursors. With a reliable ligand
synthesis in hand, we next turned our attention towards exploring its coordination chemistry with
ruthenium. Our initial efforts focussed on installing ligand 1 on ruthenium-cyclopentadienyl
precursors (Scheme 2). For example, stirring a 1:1 mixture of CpRuCl(PPh3)2 and ligand 1 in
refluxing 1,2-dichloroethane leads to the substitution of the chloride ligand and one PPh3 ligand,
and yields the yellow, air-stable, chelated zwitterionic complex 2 in 88% yield. The corresponding

ACCEPTED MANUSCRIPT
reaction with Cp*RuCl(PPh3)2 occurs under milder conditions (i.e., at room temperature), and
produces yellow-orange complex 3 in very similar yields. These results contrast most other
reactions between (η5-C5R5)RuCl(PPh3)2 (R = H or Me) and neutral bidentate phosphine ligands,
where often both PPh3 ligands are displaced, and the chloride is retained as a ligand in the
product.23 The 31P{1H} NMR spectra of 2 and 3 each reveal two doublets of an AX pattern
corresponding to the PPh3 ligand (δA 49.7 ppm for 2, δA 50.1 ppm for 3) and the -PPh2 group (δX
17.6 ppm for 2, δX 20.1 ppm for 3) of the chelated ligand 1, with cis 2JPP coupling constants of 36
Hz and 33 Hz, respectively. The chiral ruthenium centres of 2 and 3 cause the protons of the
ligand’s bridging methylene group to be diastereotopic, with each group appearing as two doublets
of an AB spin pattern (δA 5.09 ppm and δB 4.71 ppm for 2, δA 5.00 ppm and δB 4.57 ppm for 3, both
with 2JHH = 16 Hz) in their respective 1H NMR spectra. In situ monitoring of each reaction by
31P{1H} NMR spectroscopy at regular intervals showed only a steady increase in the
concentrations of 2, 3 and free PPh3, and a decrease in concentrations of CpRuCl(PPh3)2 or
Cp*RuCl(PPh3)2. No monodentate intermediates were observed, suggesting chelation rapidly
occurs following initial ligand displacement in the formation of 2 and 3. For comparison, reactions
between CpRuCl(PPh3)2 and either 2-(diphenylphosphino)pyridine24 or
4-(diphenylphosphino)-2-isopropylimidazole25 result in the displacement of only one ligand – the
PPh3 ligand – to yield the monodentate products; ring-closing only occurs once a halide abstractor
has been added. In these cases, formation of the strained four-membered chelate ring only occurs
on irreversible removal of a ligand, in this case the chloride. This also seems to be the case for 2
and 3 since both PPh3 and LiCl are formed as by-products. Interestingly, when either
CpRuCl(PPh3)2 or Cp*RuCl(PPh3)2 is mixed with the Ph4P+ salt of ligand 1 in 1,2-dichloroethane,
no reaction is observed, even under reflux conditions. Indeed, LiCl is much less soluble in

ACCEPTED MANUSCRIPT
1,2-dichloroethane than Ph4PCl, and these results suggest halide displacement is likely the first
step in the reaction towards the formation of 2, and not phosphine displacement.
Crystals of 2•2CH2Cl2•(CH3CH2)2O suitable for a crystallographic study were obtained
from a CH2Cl2/diethyl ether mixture. The solid-state structure reveals several interesting features.
As expected, complex 2 adopts a three-legged piano-stool structure typically observed for η5-Cp
and -Cp* complexes of ruthenium, with the remaining octahedral sites occupied by a PPh3 ligand,
and the κ2-PPhNBPh4 ligand (Figure 1). Several structural features of the κ2-P,N ligand clearly
show the strain of the chelate. The angles around the C(6) carbon atom of the benzimidazole
moiety bearing the -PPh2 group reveal a substantial amount of bending in order to accommodate
the chelate (i.e., P(1)-C(6)-N(1) = 104.4(4)° vs. P(1)-C(6)-N(2) = 142.0(4)°). Moreover, the -PPh2
group is pulled out of the plane of the planar benzimidazole group by about 13°. The
N(1)-Ru(1)-P(1) chelate bite angle of 67.6(1)° is small, but not unusual.26 The distance between
the ruthenium and the -PPh2 group (Ru(1)-P(1) = 2.342(2) Å) is slightly longer than that observed
between the ruthenium and the PPh3 ligand (Ru(1)-P(2) = 2.316(2) Å), and this is undoubtedly
attributed to the strained chelate. The different ruthenium-phosphorus distances seem to impact the
distances between the ruthenium and the carbon atoms of the cyclopentadienyl ligand. For
example, the PPh3 ligand adopts a position that is roughly trans to the C(1)-C(2) bond of the
cyclopentadienyl ligand, with the plane containing the ruthenium-PPh3 vector Ru(1)-P(2)
approximately bisecting C(1)-C(2). The ruthenium-carbon distances here are the longest
(Ru(1)-C(1) = 2.233(7) Å and Ru(1)-C(2) = 2.217(7) Å). In contrast, the position of the -PPh2
moiety is roughly trans to the C(3)-C(4) bond of the cyclopentadienyl ligand, with the Ru(1)-P(1)
plane approximately bisecting C(3)-C(4). Here, the ruthenium-carbon distances are the shortest
(Ru(1)-C(3) = 2.178(8) Å and Ru(1)-C(4) = 2.167(8) Å). The remaining Ru(1)-C(5) distance

ACCEPTED MANUSCRIPT
(2.193(6) Å) is intermediate between the two sets. Perhaps these differences in
Ru-C(cyclopentadienyl) distances may be linked to the inability of the -PPh2 group to exert its
trans influence to the same extent as the PPh3 ligand as a result of the strained metallacycle.
One of the original intentions of this work was to establish whether or not ligand 1 would
display hemilabile character when coordinated to ruthenium. To test for this, the chelated
complexes 2 and 3 were treated with CO under various conditions.27 Unfortunately, in all cases,
the NMR spectra revealed a number of compounds had formed, including free PPh3. Considering
the complexity of the NMR spectra, and the production of PPh3, the formation of ring-opened,
including bridged-species,25,26a cannot be ruled out in these reactions. We therefore considered
other precursors to test for hemilability. Since the synthesis of 2 and 3 likely proceeds via initial
halide displacement, we reasoned that the complex Cp*RuCl(CO)228 would be a good candidate to
examine in reactions with ligand 1. When equimolar amounts of Cp*RuCl(CO)2 and ligand 1 are
refluxed together in 1,2-dichloroethane over 24 hours (Scheme 3), a mixture of the monodentate
(4) and ring-closed (5) zwitterionic complexes are formed in an approximately 3:2 ratio. In situ
monitoring of the reaction progress at regular intervals by 31P{1H} NMR spectroscopy revealed
complex 4 forms first, and it is slowly converted to the chelated complex 5 before ligand 1 is
completely consumed. Unfortunately, complex 5 slowly decomposes with prolonged heating (i.e.,
to ensure complete conversion from complex 4), and this prevented its isolation in pure form.
Complex 4 exhibits a singlet at δ 36.1 ppm in the 31P{1H} NMR spectrum, while the singlet for 5
appears at δ 19.4 ppm. These results are consistent with the large chemical shift differences
invariably observed between chelated phosphine ligands forming four-membered rings with a
metal, and their corresponding ring-opened structures.29 As was observed for complexes 2 and 3,
the 1H NMR spectrum of 5 provides strong evidence for chelation. Consistent with the chirality of

ACCEPTED MANUSCRIPT
5, two distinct doublets of an AB spin pattern (δA 5.15 ppm and δB 4.99 ppm, 2JHH = 16 Hz) are
observed, which correspond to the diastereotopic protons of the methylene group bridging the
tetraphenyborate group to the phosphinobenzimidazole moiety. In contrast, C2v-symmetric 4
displays a singlet at δ 4.75 ppm for the bridging methylene group of the κ1-ligand. Importantly,
Scheme 3 also illustrates the hemilabile nature of ligand 1 as part of complexes 4 and 5. Thus, pure
complex 4 in CH2Cl2 slowly evolves CO when heated, and undergoes ring-closing to produce
complex 5. When complex 5 is dissolved in CH2Cl2 and allowed to stir under CO, it undergoes
ring-opening and adds a second CO ligand to yield the monodentate complex 4.
Reactions of Complexes 2 and 3 with Alkynes. We have had a long-standing interest in
the synthesis and chemistry of ruthenium vinylidene and higher cumulene complexes, mainly
because they may be employed as precursors to ruthenium carbyne complexes.30 Encouraged by
our observations from the reactions of 2 and 3 with CO, and the hemilabile properties displayed by
4 and 5, we wondered if the chelated complexes 2 and 3 might serve as suitable precursors to
vinylidene complexes if they, too, could undergo ring-opening in the presence of alkyne
substrates.31,32 As illustrated in Scheme 4, when complex 2 is stirred with a 10-fold excess of
phenylacetylene in CH2Cl2 over 24 hours, a dark red-orange solution is produced from which a
microcrystalline red-orange solid is obtained upon work-up. NMR spectroscopic analysis of the
solid reveals the clean formation of a mixture of the E- and Z-isomers of the vinylidene insertion
product 6 in approximately a 4:1 ratio. The 31P{1H} and 1H NMR spectra clearly show that 6
contains inequivalent phosphine ligands and a chiral metal. The 13C{1H} NMR spectrum of 6
perhaps offers the most compelling evidence for insertion, and shows two sets of overlapping
doublets at δ 159.6 ppm (major) and δ 155.0 ppm (minor) corresponding to Cα of the alkenyl
ligands coupling with the PPh3 ligand and -PPh2 portion of coordinated ligand 1.31b Interestingly,

ACCEPTED MANUSCRIPT
when we repeated this reaction but instead using excess 1-hexyne, only one isomer (7) is produced.
Moreover, the reactions between complex 3 and either excess phenylacetylene or 1-hexyne also
preferentially produced only one isomer (complexes 8 and 9, respectively).33
Scheme 5 illustrates a plausible mechanism by which the vinylidene insertion complexes
6-9 may form.31 The precursors 2 or 3 first undergo ring-opening to yield unsaturated κ1-PPhNBPh4
intermediates that rapidly coordinate and isomerize the alkyne to an intermediate vinylidene
complex. The vinylidene intermediate then undergoes attack at strongly electrophilic Cα by the
pendant, nucleophilic benzimidazole nitrogen of the κ1-PPhNBPh4 ligand to yield the ring-closed
product. The ring-closing process is especially facile since the nucleophilic attack occurs in an
intramolecular, chelate-assisted fashion. Certainly, the relief in ring-strain upon switching from
the 4-membered to the 5-membered metallacycle assists this process. We attempted to detect the
vinylidene intermediates via in situ monitoring of the reactions by NMR spectroscopy, but saw no
evidence of their formation. To establish the likelihood of this intermediate, the complex
Cp*RuCl(CCHPh)(PPh3)34 – which contains a preformed vinylidene ligand – was reacted
sequentially with AgOTf and ligand 1 in THF. NMR spectroscopic analysis of the red solid
isolated from the reaction showed it to be complex 8, thus suggesting the vinylidene intermediate
in Scheme 5 is plausible.
Summary
With careful control of the reaction conditions, the tetraphenyborate-functionalized,
heterobidentate phosphinobenzimidazole ligand 1 can be prepared in good yield. Ligand 1 readily
reacts with the ruthenium piano-stool precursors (η5-C5R5)RuCl(PPh3)2 (R = H or Me) via a
mechanism that appears to include initial chloride – and not phosphine – displacement. The
hard/soft mismatch between the benzimidazole moiety and the ruthenium centre, and the strained

ACCEPTED MANUSCRIPT
bite angle of the chelated complexes, undoubtedly encourage the hemilabile character of ligand 1.
Indeed, the metallacycle readily ring-opens at the ruthenium-nitrogen bond in the presence of
π-acids such as CO and vinylidene ligands (in the latter case, via terminal alkynes).
Experimental
All experiments and manipulations were conducted under an inert atmosphere of
prepurified nitrogen using standard Schlenk techniques. Hexanes, CH2Cl2 and 1,2-dichloroethane
were pre-dried over activated 4Å molecular sieves, passed through a column of alumina, purged
with N2 and stored over 4Å molecular sieves in bulbs with Teflon taps.35 Diethyl ether and THF
were freshly distilled from sodium metal under nitrogen. CDCl3 (dried over anhydrous CaCl2) and
CD2Cl2 (dried over CaH2) were vacuum distilled, freeze-pump-thaw degassed three times, and
stored in bulbs with Teflon taps. NMR spectra (1H, 13C{1H}, 31P{1H}, 11B{1H} and 7Li) were
obtained using a Varian Unity INOVA 500 MHz spectrometer, with chemical shifts (in ppm)
referenced to residual solvent peaks (1H and 13C), external 85% H3PO4 (31P), external BF3•OEt2
solution (11B), or external LiCl in D2O. Infrared spectra were acquired using a Nicolet 380 FT-IR
spectrometer. Elemental analyses were obtained from the Lakehead University Instrumentation
Laboratory. CpRuCl(PPh3)2,36 Cp*RuCl(PPh3)2,37 Cp*RuCl(CO)2,28 Cp*RuCl(CCHPh)(PPh3),34
and 1-(4-bromobenzyl)benzimidazole15 were synthesized using previously reported procedures.

ACCEPTED MANUSCRIPT
Synthesis of 1-(4-bromobenzyl)-2-(diphenylphosphino)benzimidazole. Lithium
diisopropylamide (LDA) was first synthesized by adding n-BuLi (6.97 mmol, 4.40 mL of a 1.6 M
solution in hexanes) to diisopropylamine (6.97 mmol, 976 ꢀL) in THF (5 mL) at -78ΕC. After 1
hour at -78ΕC, the LDA solution was then added via cannula to a THF (30 mL) solution of
1-(4-bromobenzyl)benzimidazole (2.00 g, 6.97 mmol) pre-cooled to -78ΕC. The bright orange
solution was stirred at -78ΕC for 1 hour. Next, ClPPh2 (6.97 mmol, 1.25 mL) was added to the
cooled orange solution via syringe. The mixture was left in the cooling bath and allowed to warm
slowly to room temperature over 2 hours. After this time, the volatiles were removed under
reduced pressure to yield a tacky orange solid. The solid was extracted into CH2Cl2 (5 Η 10 mL)
and filtered through Celite. Removal of the volatiles under reduced pressure yielded a pale yellow
solid. Yield: 3.16 g (96%). 1H NMR (500 MHz, 22ΕC, CDCl3): 7.85 (d, 1 H, 2JHH = 8.5 Hz, C8H),
7.50-7.19 (overlapping m, 15 H, Ph of -PPh2, C5H-C7H, C3ʹH and C5ʹH), 6.80 (d, 2 H, 2JHH = 8.5
Hz, C2ʹH, C6ʹH), 5.55 (d, 2 H, 4JPH = 3 Hz, -CH2-). 13C{1H} NMR (125 MHz, 22ΕC, CDCl3): 154.4
(d, 1JPC = 9 Hz, C2), 144.6-128.4 (Ph, C1ʹ-C6ʹ and C4, C9), 123.5, 122.4 (both s, C6 and C7), 120.8 (s,
C5), 110.0 (s, C8), 47.8 (d, 3JPC = 15 Hz, -CH2-). 31P{1H} NMR (202 MHz, 22ΕC, CDCl3): -28.3 (s,
-PPh2).
Synthesis of [Li(THF)2][PPhNBPh4], 1. The compound
1-(4-bromobenzyl)-2-(diphenylphosphino)benzimidazole (1.00 g, 2.13 mmol) was dissolved in
THF (30 mL) and the solution was cooled to -80ΕC (isopropanol/LN2). Next, t-BuLi (2.13 mmol,
1.25 mL of 1.7 M solution in pentane) was added dropwise via syringe to the cooled solution over
about 2 minutes yielding a dark orange solution. The solution was stirred and kept between -80ΕC
and -90ΕC for 1 hour. The solution was maintained at -90ΕC, and then BPh3 (0.516 g, 2.13 mmol)
in THF (8 mL) was added very slowly dropwise via syringe over 30 minutes. The orange solution

ACCEPTED MANUSCRIPT
was stirred at -90ΕC for 2 hours, and then it was allowed to warm slowly to room temperature
overnight while in the cooling bath. The next day, excess hexanes (~100 mL) were added to the
light orange solution producing an orange oil. The mixture was allowed to stand for about 3 hours,
and then the supernatant was decanted. The remaining orange oil was washed with hexanes (2 Η
20 mL) and then dried under reduced pressure to yield a powdery pale yellow solid. Yield: 1.20 g
(73%). 1H NMR (500 MHz, 22ΕC, CDCl3): 7.62 (d, 1 H, 2JHH = 8 Hz, C8H), 7.47-6.89
(overlapping m, 30 H, Ph of -PPh2 and BPh3, C5H-C7H and C3ʹH, C5ʹH), 6.79 (d, 2 H, 2JHH = 8 Hz,
C2ʹH, C6ʹH), 5.31 (s, 2 H, -CH2-), 3.60 (m, 8 H, THF), 1.79 (m, 8 H, THF). 13C{1H} NMR (125
MHz, 22ΕC, CDCl3): 165.0 (q, 1JBC = 48 Hz, C4ʹ), 163.9 (q, 1JBC = 50 Hz, ipso C of B-Ph), 155.7
(d, 1JPC = 16 Hz, C2), 142.7-123.3 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4 and C9), 121.9 (s, C6, C7), 117.9 (s, C5),
112.5 (s, C8), 88.7 (s, C5Me5), 68.6 (s, THF), 50.0 (s, -CH2-), 25.5 (s, THF). 31P{1H} NMR (202
MHz, 22ΕC, CDCl3): -24.1 (s, -PPh2). 11B{1H} NMR (160 MHz, 22ΕC, CDCl3): -6.7 ppm (s). 7Li
NMR (195 MHz, 22ΕC, CDCl3): -0.35 ppm (s).
Synthesis of [CpRu(PPh3)(κ2P,N-PPhNBPh4)], 2. CpRuCl(PPh3)2 (0.139 g, 0.191 mmol)
and ligand 1 (0.150 g, 0.191 mmol) were combined and dissolved in 1,2-dichloroethane (10 mL).
The orange mixture was refluxed for 24 hours. The next day, the cloudy orange-yellow mixture
was allowed to cool to room temperature and then it was filtered through Celite. The volatiles were
removed from the filtrate and the orange-yellow solid that remained was washed with diethyl ether
(4 Η 20 mL) to remove the PPh3. The yellow-orange product was dried under reduced pressure.
Yield: 0.178 g (88%). Recrystallization from CH2Cl2/diethyl ether yielded analytically pure
samples. Anal. Calcd. for C67H55BN2P2Ru•0.5CH2Cl2: C, 73.4; H, 5.11; N, 2.54. Found: C, 73.8;
H, 5.11; N, 2.62. 1H NMR (500 MHz, 22ΕC, CD2Cl2): 7.41-6.78 (overlapping m, 46 H, Ph of
-PPh2, PPh3 and BPh3, C5H-C8H, and C3ʹH, C5ʹH), 6.42 (d, 2 H, 2JHH = 8 Hz, C2ʹH, C6ʹH), 5.09 (d, 2

ACCEPTED MANUSCRIPT
H, 2JHH = 16 Hz, -CHAHB- ), 4.70 (d, 1 H, 2JHH = 16 Hz, -CHAHB-), 4.43 (s, 5 H, Cp). 13C{1H}
NMR (125 MHz, 22ΕC, CD2Cl2): 165.9 (q, 1JBC = 49 Hz, C4ʹ), 164.0 (q, 1JBC = 49 Hz, ipso C of
B-Ph), 156.6 (d, 1JPC = 31 Hz, C2), 143.4-124.3 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4 and C9), 122.5 (s, C6, C7),
117.6 (s, C5), 113.6 (s, C8), 78.7 (s, C5H5), 50.2 (s, -CH2-). 31P{1H} NMR (202 MHz, 22ΕC,
CD2Cl2): 49.8 (d, 2JPP = 36 Hz, PPh3), 17.9 (d, 2JPP = 36 Hz, -PPh2). 11B{1H} NMR (160 MHz,
22ΕC, CD2Cl2): -6.6 ppm (s).
Synthesis of [Cp*Ru(PPh3)(κ2P,N-PPhNBPh4)], 3. Cp*RuCl(PPh3)2 (0.100 g, 0.125
mmol) and ligand 1 (0.099 g, 0.125 mmol) were combined and dissolved in CH2Cl2 (10 mL). The
orange solution was allowed to stir for 24 hours. The next day, the hazy, light orange mixture was
filtered through Celite, and then the volatiles were removed from the filtrate under reduced
pressure. The light orange solid was then washed with diethyl ether (4 Η 20 mL) to remove the
PPh3. The yellow-orange product was dried under reduced pressure. Yield: 0.126 g (89%).
Recrystallization from CH2Cl2/diethyl ether yielded analytically pure samples. Anal. Calcd. for
C75H65BN2P2Ru•CH2Cl2: C, 74.1; H, 5.66; N, 2.38. Found: C, 74.4; H, 5.69; N, 2.54. 1H NMR
(500 MHz, 22ΕC, CDCl3): 7.72 (d, 1 H, 2JHH = 8 Hz, C8H), 7.51-6.73 (overlapping m, 45 H, Ph of
-PPh2, PPh3 and BPh3, C5H-C7H, and C3ʹH, C5ʹH), 6.49 (d, 2 H, 2JHH = 8 Hz, C2ʹH, C6ʹH), 4.99 (d, 1
H, 2JHH = 16 Hz, -CHAHB- ), 4.58 (d, 1 H, 2JHH = 16 Hz, -CHAHB-), 1.33 (s, 15 H, Cp*). 13C{1H}
NMR (125 MHz, 22ΕC, CDCl3): 166.2 (q, 1JBC = 49 Hz, C4ʹ), 163.6 (q, 1JBC = 50 Hz, ipso C of
B-Ph), 156.4 (d, 1JPC = 33 Hz, C2), 142.2-124.1 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4 and C9), 121.8 (s, C6, C7),
116.8 (s, C5), 114.2 (s, C8), 88.7 (s, C5Me5), 51.0 (s, -CH2-), 10.8 (s, -CH3 of Cp*). 31P{1H} NMR
(202 MHz, 22ΕC, CDCl3): 50.1 (d, 2JPP = 33 Hz, PPh3), 20.1 (d, 2JPP = 33 Hz, -PPh2). 11B{1H}
NMR (160 MHz, 22ΕC, CDCl3): -6.6 ppm (s).
Synthesis of [Cp*Ru(CO)2(κ1P-PPhNBPh4)], 4, and [Cp*Ru(CO)(κ2P,N-PPhNBPh4)],

ACCEPTED MANUSCRIPT
5. Cp*RuCl(CO)2 (0.0500 g, 0.153 mmol) and ligand 1 (0.120 g, 0.153 mmol) were combined,
dissolved in 1,2-dichloroethane (5 mL), and refluxed for 24 hours. The next day, the cloudy yellow
mixture was allowed to cool to room temperature, and then it was filtered through Celite. The
volatiles were removed from the filtrate and the yellow solid was washed with diethyl ether (10
mL) before drying under reduced pressure. NMR spectroscopic analysis of the product revealed it
to be a mixture of complexes 4 and 5 in an approximately 3:2 ratio. Complete NMR data of
complex 4 is given below; selected NMR data for complex 5 follows: 1H NMR (500 MHz, 22ΕC,
CDCl3): 6.56 (d, 2 H, 2JHH = 7.5 Hz, C2ʹH, C6ʹH), 5.15 (d, 1 H, 2JHH = 15 Hz, -CHAHB- ), 4.99 (d, 1
H, 2JHH = 16 Hz, -CHAHB-), 1.72 (s, 15 H, Cp*). 31P{1H} NMR (202 MHz, 22ΕC, CDCl3): 19.4 (s,
-PPh2). 11B{1H} NMR (160 MHz, 22ΕC, CDCl3): -6.6 ppm (s).
Synthesis of [Cp*Ru(CO)2(κ1P-PPhNBPh4)], 4. Cp*RuCl(CO)2 (0.0500 g, 0.153 mmol)
and ligand 1 (0.120 g, 0.153 mmol) were combined, dissolved in 1,2-dichloroethane (5 mL), and
refluxed for 24 hours. After cooling to room temperature, the cloudy yellow mixture was then
filtered through Celite. The volatiles were removed from the filtrate under reduced pressure
yielding a yellow solid. The flask was then backfilled with CO, and then CH2Cl2 (5 mL) was
added. The dark yellow solution was allowed to stir under CO for 24 hours. After this time, the
volatiles were removed under reduced pressure yielding a pale yellow solid. The solid was washed
with diethyl ether (20 mL) before drying under reduced pressure. Yield: 0.120 g (85%).
Recrystallization from CH2Cl2/diethyl ether yielded analytically pure samples. Anal. Calcd. for
C59H61BN2O2PRu: C, 72.8; H, 6.32; N, 2.88. Found: C, 72.3; H, 5.90; N, 3.21. IR (Nujol): 2044
(s), 1994 (s). 1H NMR (500 MHz, 22ΕC, CDCl3): 7.83 (d, 1 H, 2JHH = 8 Hz, C8H), 7.37-6.81
(overlapping m, 30 H, Ph of -PPh2 and BPh3, C5H-C7H and C3ʹH, C5ʹH), 6.11 (d, 2 H, 2JHH = 8 Hz,
C2ʹH, C6ʹH), 4.76 (s, 2 H, -CH2-), 1.68 (s, 15 H, Cp*). 13C{1H} NMR (125 MHz, 22ΕC, CDCl3):

ACCEPTED MANUSCRIPT
198.1 (d, 2JPC = 15 Hz, CO), 164.5 (q, 1JBC = 49 Hz, C4ʹ), 163.8 (q, 1JBC = 49 Hz, ipso C of B-Ph),
143.2 (d, 1JPC = 21 Hz, C2), 138.6-123.0 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4 and C9), 121.8 (s, C6,C7), 120.5 (s,
C5), 113.1 (s, C8), 103.1 (s, C5Me5), 50.2 (s, -CH2-), 9.75 (s, -CH3 of Cp*). 31P{1H} NMR (202
MHz, 22ΕC, CDCl3): 36.1 (s, -PPh2). 11B{1H} NMR (160 MHz, 22ΕC, CDCl3): -6.7 ppm (s).
Synthesis of [CpRu(PPh3)(κ2C,P-(CCHPh)-PPhNBPh4)], 6. Complex 2 (0.0500 g,
0.0471 mmol) was dissolved in CH2Cl2 (2 mL). Next, phenylacetylene (52 ꢀL, 0.471 mmol) was
added to the suspension via syringe, and the mixture was allowed to stir for 24 hours. The resulting
clear red-orange solution was evaporated to dryness under reduced pressure, and the red solid that
remained was washed with diethyl ether (2 Η 15 mL). The product was recrystallized from
THF/hexanes yielding a microcrystalline red-orange solid which was washed with diethyl ether
and dried under reduced pressure. Yield: 0.0410 g (75%). Anal. Calcd. for C75H61BN2P2Ru: C,
77.4; H, 5.28; N, 2.41. Found: C, 76.7; H, 5.54; N, 2.61. NMR spectroscopy revealed two isomers
of 6 had formed in approximately a 4:1 ratio. Selected NMR spectroscopic data for each isomer
follows. Major isomer: 1H NMR (500 MHz, 22ΕC, CDCl3): 5.78 (d, 2 H, 2JHH = 8 Hz, C2ʹH,
C6ʹH), 4.89 (d, 1 H, 2JHH = 16 Hz, -CHAHB- ), 4.71 (d, 1 H, 2JHH = 16 Hz, -CHAHB-), 4.38 (s, 5 H,
Cp). 13C{1H} NMR (125 MHz, 22ΕC, CDCl3): 166.2 (q, 1JBC = 48 Hz, C4ʹ), 163.5 (q, 1JBC = 50 Hz,
ipso C of B-Ph), 159.6 (dd, 2JPC = 18 Hz, 2JPC = 17 Hz, Cα), 152.2 (d, 1JPC = 22 Hz, C2), 121.9 (s,
C6, C7), 117.7 (s, C5), 116.1 (s, C8), 86.2 (s, C5H5), 52.7 (s, -CH2-). 31P{1H} NMR (202 MHz,
22ΕC, CDCl3): 69.0 (d, 2JPP = 35 Hz, PPh3), 49.1 (d, 2JPP = 35 Hz, -PPh2). Minor isomer: 1H
NMR (500 MHz, 22ΕC, CDCl3): 6.00 (d, 2 H, 2JHH = 8 Hz, C2ʹH, C6ʹH), 5.15 (d, 1 H, 2JHH = 16 Hz,
-CHAHB- ), 4.98 (d, 1 H, 2JHH = 16 Hz, -CHAHB-), 4.62 (s, 5 H, Cp). 13C{1H} NMR (125 MHz,
22ΕC, CDCl3): 166.4 (q, 1JBC = 49 Hz, C4ʹ), 163.5 (q, 1JBC = 50 Hz, ipso C of B-Ph), 155.0 (dd, 2JPC
= 22 Hz, 2JPC = 12 Hz, Cα), 153.0 (d, 1JPC = 19 Hz, C2), 121.9 (s, C6, C7), 118.4 (s, C5), 114.2 (s,

ACCEPTED MANUSCRIPT
C8), 87.3 (s, C5H5), 53.5 (s, -CH2-). 31P{1H} NMR (202 MHz, 22ΕC, CDCl3): 69.6 (d, 2JPP = 35
Hz, PPh3), 50.8 (d, 2JPP = 35 Hz, -PPh2).
Synthesis of [CpRu(PPh3)(κ2C,P-(CCHBu)-PPhNBPh4)], 7. Complex 2 (0.0600 g,
0.0565 mmol) was dissolved in CH2Cl2 (3 mL). Next, 1-hexyne (65 ꢀL, 0.565 mmol) was added to
the suspension via syringe, and the mixture was allowed to stir for 24 hours. The now clear orange
solution was evaporated to dryness under reduced pressure, and the orange solid that remained was
washed with diethyl ether (2 Η 10 mL). The product was dried under reduced pressure. Yield:
0.0640 g (84%). Recrystallization from CH2Cl2/hexanes yielded analytically pure samples. Anal.
Calcd. for C73H65BN2P2Ru•0.5CH2Cl2: C, 74.4; H, 5.61; N, 2.36. Found: C, 74.6; H, 5.79; N, 2.65.
1H NMR (500 MHz, 22ΕC, CDCl3): 7.87 (d, 1 H, 2JHH = 8 Hz, C8H), 7.53-6.80 (overlapping m, 46
H, Ph of -PPh2, PPh3 and BPh3, C5H-C7H, C3ʹH, C5ʹH and CβH), 5.89 (d, 2 H, 2JHH = 8 Hz, C2ʹH,
C6ʹH), 5.02 (d, 1 H, 2JHH = 15 Hz, -CHAHB- ), 4.88 (d, 1 H, 2JHH = 16 Hz, -CHAHB-), 4.68 (s, 5 H,
Cp), 2.45 (br m, 2 H, n-Bu), 1.67 (br m, 2 H, n-Bu), 1.55 (br m, 2 H, n-Bu), 1.10 (t, 3 H, 3JHH = 7
Hz, n-Bu). 13C{1H} NMR (125 MHz, 22ΕC, CDCl3): 166.3 (q, 1JBC = 48 Hz, C4ʹ), 163.4 (q, 1JBC
49 Hz, ipso C of B-Ph), 154.7 (dd, 2JPC = 16 Hz, 2JPC = 21 Hz, Cα), 150.8 (d, 1JPC = 23 Hz, C2),
=
137.9-123.2 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4, C9 and Cβ), 121.9 (s, C6, C7), 117.9 (s, C5), 115.5 (s, C8), 84.8
(s, C5H5), 52.8 (s, -CH2-), 33.8 (s, n -Bu), 33.2 (s, n-Bu), 23.3 (s, n-Bu), 14.4 (s, n-Bu). 31P{1H}
NMR (202 MHz, 22ΕC, CDCl3): 69.0 (d, 2JPP = 34 Hz, PPh3), 52.2 (d, 2JPP = 34 Hz, -PPh2).
11B{1H} NMR (160 MHz, 22ΕC, CDCl3): -6.7 ppm (s).
Synthesis of [Cp*Ru(PPh3)(κ2C,P-(CCHPh)-PPhNBPh4)], 8. (a) Method A. Complex 3
(0.0500 g, 0.0442 mmol) was dissolved in CH2Cl2 (4 mL). Next, phenylacetylene (49 ꢀL, 0.442
mmol) was added to the solution via syringe, and the mixture was allowed to stir for 24 hours. The
resulting clear dark red solution was evaporated to dryness under reduced pressure, and the red

ACCEPTED MANUSCRIPT
solid that remained was washed with diethyl ether (2 Η 15 mL).Yield: 0.031 g (60%).
Recrystallization from CH2Cl2/hexanes yielded analytically pure samples. Anal. Calcd. for
C80H71BN2P2Ru•0.5CH2Cl2: C, 75.7; H, 5.68; N, 2.19. Found: C, 75.3; H, 6.33; N, 2.04. 1H NMR
(500 MHz, 22ΕC, CDCl3): 7.69-6.78 (overlapping m, 44 H, Ph of -PPh2, PPh3 and BPh3, C5H,
C8H, C3ʹH and C5ʹH), 6.76 (s, 1 H, CβH), 6.64-6.37 (m, 5 H, Ph), 6.18 (br, 2 H, C6H, C7H), 5.83 (d,
2 H, 2JHH = 8 Hz, C2ʹH, C6ʹH), 5.05 (d, 1 H, 2JHH = 15 Hz, -CHAHB-), 4.74 (d, 1 H, 2JHH = 15 Hz,
-CHAHB-), 1.30 (s, 15 H, Cp*). 13C{1H} NMR (125 MHz, 22ΕC, CDCl3): 166.0 (q, 1JBC = 48 Hz,
C4ʹ), 163.4 (q, 1JBC = 50 Hz, ipso C of B-Ph), 162.2 (dd, 2JPC = 18 Hz, 2JPC = 22 Hz, Cα), 155.2 (d,
1JPC = 21 Hz, C2), 139.4-123.1 (Ph, C1ʹ-C3ʹ, C5ʹ, C6ʹ, C4, C9 and Cβ), 121.9 (s, C6, C7), 119.1 (s, C5),
114.4 (s, C8), 95.6 (s, C5Me5), 53.2 (s, -CH2-), 9.91 (s, -CH3 of Cp*). 31P{1H} NMR (202 MHz,
22ΕC, CDCl3): 67.1 (d, 2JPP = 32 Hz, PPh3), 51.9 (d, 2JPP = 32 Hz, -PPh2). 11B{1H} NMR (160
MHz, 22ΕC, CDCl3): -6.7 ppm (s).
(b) Method B. Cp*RuCl(CCHPh)(PPh3) (0.100 g, 0.157 mmol) and AgOTf (0.040 g, 0.157
mmol) were combined, dissolved in THF (10 mL) and allowed to stir for 30 minutes. Ligand 1
(0.124 g, 0.157 mmol) in THF was added via cannula to the deep, dark purple solution turning it
cloudy, dark orange-red. The mixture was allowed to stir for 1 hour, and then the volatiles were
removed under reduced pressure. The product was extracted into CH2Cl2 (20 mL) and filtered
through Celite. The volatiles were removed from the deep, dark red filtrate yielding a red solid.
The solid was washed with diethyl ether (15 mL) before drying under reduced pressure. Yield:
0.131 g (68%). The NMR spectroscopic data of the red solid were identical to that observed for the
product isolated using Method A.
Synthesis of [Cp*Ru(PPh3)(κ2C,P-(CCHBu)-PPhNBPh4)], 9. Complex 3 (0.0700 g,
0.0618 mmol) was dissolved in CH2Cl2 (4 mL). Next, 1-hexyne (71 ꢀL, 0.618 mmol) was added to

ACCEPTED MANUSCRIPT
the solution via syringe, and the mixture was allowed to stir for 24 hours. The resulting clear
orange solution was evaporated to dryness under reduced pressure, and the orange-red solid that
remained was washed with diethyl ether (2 Η 15 mL).Yield: 0.0420 g (56%). Recrystallization
from CH2Cl2/hexanes and washing with diethyl ether yielded analytically pure samples. Anal.
Calcd. for C78H75BN2P2Ru•0.5CH2Cl2: C, 75.0; H, 6.10; N, 2.23. Found: C, 75.5; H, 5.97; N, 2.56.
1H NMR (500 MHz, 22ΕC, CDCl3): 7.64-6.19 (overlapping m, 46 H, Ph of -PPh2, PPh3 and BPh3,
C5H-C8H, C3ʹH, C5ʹH), 5.82 (d, 1JHH = 8 Hz, C2ʹH, C6ʹH), 5.57 (m, 1 H, CβH), 5.05 (d, 1 H, 2JHH
=
15 Hz, -CHAHB- ), 4.68 (d, 1 H, 2JHH = 15 Hz, -CHAHB-), 2.34 (br m, 1 H, n-Bu), 2.04 (br m, 1 H,
n-Bu), 1.58 (br m, 4 H, n-Bu), 1.27 (s, 15 H, Cp*), 0.96 (t, 3 H, 3JHH = 7 Hz, n-Bu). 13C{1H} NMR
(125 MHz, 22ΕC, CDCl3): 166.2 (q, 1JBC = 48 Hz, C4ʹ), 163.4 (q, 1JBC = 49 Hz, ipso C of B-Ph),
154.2 (d, 1JPC = 19 Hz, C2), 153.3 (dd, 2JPC = 22 Hz, 2JPC = 19 Hz, Cα), 136.6-123.5 (Ph, C1ʹ-C3ʹ,
C5ʹ, C6ʹ, C4 and C9), 121.9 (s, C6, C7), 121.6 (s, Cβ), 118.4 (s, C5), 114.9 (s, C8), 94.8 (s, C5Me5),
53.1 (s, -CH2-), 34.9 (s, n -Bu), 33.9 (s, n-Bu), 22.7 (s, n-Bu), 14.3 (s, n-Bu), 9.84 (s, -CH3 of Cp*).
31P{1H} NMR (202 MHz, 22ΕC, CDCl3): 66.5 (d, 2JPP = 33 Hz, PPh3), 52.5 (d, 2JPP = 33 Hz,
-PPh2). 11B{1H} NMR (160 MHz, 22ΕC, CDCl3): -6.8 ppm (s).
X-ray Crystallography. A clear, yellow rod-like specimen of 2•2CH2Cl2•(CH3CH2)2O,
with approximate dimensions 0.06 mm x 0.13 mm x 0.19 mm, was used for the X-ray
crystallographic analysis. The X-ray intensity data were measured on a Bruker Apex2
diffractometer using MoKα radiation. Data were collected on a Bruker Apex2 SMART CCD
system with MoKα radiation at -100°C. Consecutive 0.5 degree omega scans were used to ensure
complete coverage, and the total exposure time was 2.96 hours. The frames were integrated with
the Bruker SAINT software package (Apex2 2013.10.1) using a narrow-frame algorithm. The
integration of the data using an orthorhombic unit cell yielded a total of 59803 reflections to a

ACCEPTED MANUSCRIPT
maximum θ angle of 28.33° (0.75 Å resolution), of which 16002 were independent (average
redundancy 3.737, completeness = 99.6%, R(int) = 5.98%, Rσ = 8.90%) and 12036 (75.22%) were
greater than 2σ(F2). The final cell constants of a = 16.9751(8) Å, b = 18.6007(8) Å, c = 20.4062(9)
Å, and volume = 6443.2(5) Å3, are based upon the refinement of the XYZ-centroids of 7046
reflections above 20 σ(I) with 4.553° < 2θ < 39.05°. Data were corrected for absorption effects
using the numerical method (SADABS). The ratio of minimum to maximum apparent
transmission was 0.914. The calculated minimum and maximum transmission coefficients (based
on crystal size) are 0.9093 and 0.9864. The structure was solved and refined using the Bruker
SHELXTL 2013 Software Package, using the space group P212121, with Z = 4 for the formula unit
C73H69BCl4N2OP2Ru. The final anisotropic full-matrix least-squares refinement on F2 with 743
variables converged at R1 = 5.81% for the observed data, and wR2 = 15.64% for all data. The
goodness-of-fit was 1.037. The largest peak in the final difference electron density synthesis was
1.084 e-/Å3 and the largest hole was -0.803 e-/Å3, with an RMS deviation of 0.100 e-/Å3. On the
basis of the final model, the calculated density was 1.346 g/cm3 and F(000), 2704 e-. The main
molecule showed no disorder, but three disordered solvent molecules were refined: two molecules
of CH2Cl2 (0.61(1) and 0.510(6)) and one molecule of diethyl ether (0.763(7)).
Acknowledgements
We are very grateful for the financial support provided by the Natural Sciences and
Engineering Research Council (NSERC) of Canada in the form of a Discovery Grant to G.J.S., a
PGS-D to J.M.W., and an USRA to J.P.T.
Appendix. Supplementary material
CCDC 979032 contains the supplementary crystallographic data for
2•2CH2Cl2•(CH3CH2)2O. This data can be obtained free of charge from The Cambridge

ACCEPTED MANUSCRIPT
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
References
1.
2.
3.
4.
J.C. Thomas and J.C. Peters, Inorg. Chem., 2003, 42, 5055.
C.M. Thomas and J.C. Peters, Inorg. Chem., 2004, 43, 8.
D.A. Hoic, W.M. Davis and G.C. Fu, J. Am. Chem. Soc., 1996, 118, 8176.
(a) A.L. Gott, W.E. Piers, J.L. Dutton, R. McDonald and M. Parvez, Organometallics,
2011, 30, 4236; (b) Y. Kim and R.F. Jordan, Organometallics, 2011, 30, 4250.
(a) A.-C. Gaumont, M.B. Hursthouse, S.J. Coles and J.M. Brown, Chem. Commun., 1999,
63; (b) H. Dorn, C.A. Jaska, R.A. Singh, A.J. Lough and I. Manners, Chem. Commun.,
2000, 1041; (c) G. Müller and J. Brand, Organometallics, 2003, 22, 1463; (d) F. Dornhaus,
M. Bolte, H.-W. Lerner and M. Wagner, Eur. J. Inorg. Chem., 2006, 1777; (e) F.
Dornhaus, M. Bolte, H.-W. Lerner and M. Wagner, Eur. J. Inorg. Chem., 2006, 5138; (f)
K. Izod, J.M. Watson, W. Clegg and R.W. Harrington, Eur. J. Inorg. Chem., 2012, 1696.
S.L. Granville, G.C. Welch and D.W. Stephan, Inorg. Chem., 2012, 51, 4711.
(a) A.A. Barney, A.F. Heyduk and D.G. Nocera, Chem. Commun., 1999, 2379; (b) J.C.
Peters, J.D. Feldman and T.D. Tilley, J. Am. Chem. Soc., 1999, 121, 9871; (d) I.R. Shapiro,
D.M. Jenkins, J.C. Thomas, M.W. Day and J.C. Peters, Chem. Commun., 2001, 2152; (e)
J.D. Feldman, J.C. Peters and T.D. Tilley, Organometallics, 2002, 21, 4050; (f) J.D.
Feldman, J.C. Peters and T.D. Tilley, Organometallics, 2002, 21, 4065; (g) D.M. Jenkins,
T.A. Betley and J.C. Peters, J. Am. Chem. Soc., 2002, 124, 11238; (h) D.M. Jenkins, A.J.
Di Bilio, M.J. Allen, T.A. Betley and J.C. Peters, J. Am. Chem. Soc., 2002, 124, 15336; (i)
T.A. Betley and J.C. Peters, Inorg. Chem., 2003, 42, 5074; (j) L. Turculet, J.D. Feldman
and T.D. Tilley, Organometallics, 2003, 22, 4627; (k) S.D. Brown, T.A. Betley and J.C.
5.
6.
7.

ACCEPTED MANUSCRIPT
Peters, J. Am. Chem. Soc., 2003, 125, 322; (l) T.A. Betley and J.C. Peters, J. Am. Chem.
Soc., 2003, 125, 10782; (m) S.D. Brown, T.A. Betley and J.C. Peters, J. Am. Chem. Soc.,
2003, 125, 322; (n) T.A. Betley and J.C. Peters, J. Am. Chem. Soc., 2003, 125, 10782; (o)
J.C. Thomas and J.C. Peters, Polyhedron, 2004, 23, 489; (p) S. Jiménez, J.A. López, M.A.
Ciriano, C. Tejel, A. Martínez and R.A. Sánchez-Delgado, Organometallics, 2009, 28,
3193; (q) M.C. Lipke and T.D. Tilley, J. Am. Chem. Soc., 2011, 133, 16374; (r) S.D.
Brown, T.A. Betley and J.C. Peters, J. Am. Chem. Soc., 2003, 125, 322; (s) T.A. Betley and
J.C. Peters, J. Am. Chem. Soc., 2003, 125, 10782; (t) M.A. Fuentes, E. Álvarez, A.
Caballero and P.J. Pérez, Organometallics, 2012, 31, 959; (u) C. Tejel, A.M. Geer, S.
Jiménez, J.A. López and M.A. Ciriano, Organometallics, 2012, 31, 2895.
8.
9.
A. Franzke and A. Pfaltz, Chem. Eur. J., 2011, 17, 4131.
(a) F.-G. Fontaine, J. Boudreau and M.-H. Thibault, Eur. J. Inorg. Chem., 2008, 5439; (b)
G. Bouhadir, A. Amgoune and D. Bourissou, Adv. Organomet. Chem., 2010, 58, 1.
(a) J.C. Thomas and J.C. Peters, J. Am. Chem. Soc., 2003, 125, 8870; (b) H. Hou, A.L.
Rheingold and C.P. Kubiak, Organometallics, 2005, 24, 231.
10.
11.
(a) J.-Q. Zhou and H. Alper, J. Chem. Soc., Chem. Commun., 1991, 233; (b) H. Alper and
J.-Q. Zhou, J. Chem. Soc., Chem. Commun., 1993, 316; (c) J.-Q. Zhou and H. Alper,
Organometallics, 1994, 13, 1586; (d) C.W. Lee and H. Alper, J. Org. Chem., 1995, 60,
499; (e) T.A. Betley and J.C. Peters, Angew. Chem. Int. Ed., 2003, 42, 2385; (f) M.
Stradiotto, K.D. Hesp and R.J. Lundgren, Angew. Chem. Int. Ed., 2010, 49, 494.
M.T. Beach, J.M. Walker, T.G. Larocque, J.L. Deagle, R. Wang and G.J. Spivak, J.
Organomet. Chem., 2008, 693, 2921.
12.
13.
(a) J.C. Jeffrey and T.B. Rauchfuss, Inorg. Chem., 1979, 18, 2658; (b) C.S. Slone, D.A.

ACCEPTED MANUSCRIPT
Weinberger and C.A. Mirkin, Prog. Inorg. Chem., 1999, 48, 233; (c) P. Braunstein and F.
Naud, Angew. Chem., Int. Ed., 2001, 40, 680.
14.
For related, neutral systems, see: (a) S. Harkal, F. Rataboul, A. Zapf, C. Fuhrmann, T.
Riermeier, A. Monsees and M. Bellera, Adv. Synth. Catal., 2004, 346, 1742; (b) S.M.
Wong, C.M. So, K.H. Chung, C.H. Luk, C.P. Lau and F.Y. Kwong, Tet. Lett., 2012, 53,
3754; (c) K.H. Chung, C.M. So, S.M. Wong, C.H. Luk, Z. Zhou, C.P. Lau and F.Y.
Kwong, Chem. Commun., 2012, 48, 1967; (d) B. Milde, D. Schaarschmidt, T. Rüffer and
H. Lang, Dalton Trans., 2012, 41, 5377.
15.
Y. Wan, C. Wallinder, B. Plouffe, H. Beaudry, A. K. Mahalingam, X. Wu, B. Johansson,
M. Holm, M. Botoros, A. Karlén, A. Pettersson, F. Nyberg, L. Fändriks, N. Gallo-Payet, A.
Hallberg and M. Alterman, J. Med. Chem., 2004, 47, 5995.
16.
17.
J. Ruiz and A.F. Mesa, Chem. Eur. J., 2012, 18, 4485.
(a) D.J. Irvine, C. Glidewell, D.J. Cole-Hamilton, J.C. Barnes and A. Howie, J. Chem.
Soc., Dalton Trans., 1991, 1765; (b) S. Kawaguchi, S. Nagata, T. Shirai, K. Tsuchii, A.
Nomoto and A. Ogawa, Tet. Lett., 2006, 47, 3919.
18.
19.
A. Krasovskiy and P. Knochel, Angew. Chem. Int. Ed., 2004, 43, 3333.
(a) R. Damico, J. Org. Chem., 1964, 29, 1971; (b) T. Lund, P. Christensen and R.
Wilbrandt, Org. Biomol. Chem., 2003, 1, 1020.
20.
(a) A. Wacker, H. Pritzkow and W. Siebert, Eur. J. Inorg. Chem., 1998, 843; (b) A.
Wacker, H. Pritzkow and W. Siebert, Eur. J. Inorg. Chem., 1999, 789; (c) D.P. Curran, A.
Solovyev, M.M. Brahmi, L. Fensterbank, M. Malacria and E. Lacôte, Angew. Chem. Int.
Ed., 2011, 50, 10294.
21.
H. Nöth and H. Vahrenkamp, Chem. Ber., 1966, 99, 1049.

ACCEPTED MANUSCRIPT
22.
(a) W. Clegg, K. Izod, W. McFarlane and P. O’Shaughnessy, Organometallics, 1999, 18,
3950; (b) A.G. Avent, D. Bonafoux, C. Eaborn, M.S. Hill, P.B. Hitchcock and J.D. Smith,
J. Chem. Soc., Dalton Trans., 2000, 2183; (c) L.-C. Liang, W.-Y. Lee and C.-C. Yin,
Inorg. Chem., 2003, 42, 5471; (d) L.-C. Liang, W.-Y. Lee and C.-C. Yin, Organometallics,
2004, 23, 3538; (e) E.A. MacLachlan and M.D. Fryzuk, Organometallics, 2005, 24, 1112.
(a) G.S. Ashby, M.I. Bruce, I.B. Tomkins and R.C. Wallis, Aust. J. Chem., 1979, 32, 1003;
(b) G. Consiglio, F. Morandini and F. Bangerter, Inorg. Chem., 1982, 21, 455; (c) M. I.
Bruce, M. G. Humphrey, J. M. Patrick and A. H. White, Aust. J. Chem., 1983, 36, 2065; (d)
F. Morandini, G. Consiglio, B. Straub, G. Ciani and A. Sironi, J. Chem. Soc., Dalton
Trans., 1983, 2293; (e) F.L. Joslin, J.T. Mague and D.M. Roundhill, Polyhedron, 1991, 10,
1713; (f) F. L. Joslin, M. P. Johnson, J. T. Mague and D. M. Roundhill, Organometallics,
1991, 10, 2781; (g) I. de los Ríos, M. Jiménez-Tenorio, J. Padilla, M.C. Puerta and P.
Valerga, J. Chem. Soc., Dalton Trans., 1996, 377.
23.
24.
25.
26.
P. Kumar, A. Kumar Singh, S. Sharma and D.S. Pandey, J. Organomet. Chem., 2009, 694,
3643.
P.C. Kunz, I. Thiel, A.L. Noffke, G.J. Reiß, F. Mohr and B. Spingler, J. Organomet.
Chem., 2012, 697, 33.
(a) G. Espino, F.A. Jalón, M. Maestro, B.R. Manzano, M. Pérez-Manrique and A.C.
Bacigalupe, Eur. J. Inorg. Chem., 2004, 2542; (b) G. Espino, F.A. Jalón, B.R. Manzano,
M. Pérez-Manrique, K. Mereiter and D. Quiñonero, Supramol. Chem., 2012, 1.
K. Mauthner, C. Slugovc, K. Mereiter, R. Schmid and K. Kirchner, Organometallics,
1997, 16, 1956.
27.
28.
P.J. Fagan, W.S. Mahoney, J.C. Calabrese and I.D. Williams, Organometallics, 1990, 9,

ACCEPTED MANUSCRIPT
1843.
29.
30.
Olaf Kühl, “Phosphorus-31 NMR Spectroscopy: A Concise Introduction for the Synthetic
Organic and Organometallic Chemist”. Springer: Berlin (2008).
(a) N.J. Beach, H.A. Jenkins and G.J. Spivak, Organometallics, 2003, 22, 5179; (b) N.J.
Beach and G.J. Spivak, Inorg. Chim. Acta, 2003, 343, 244; (c) N.J. Beach, A.E.
Williamson and GJ. Spivak, J. Organomet. Chem., 2005, 690, 4640; (d) N.J. Beach, J.M.
Walker, H.A. Jenkins and GJ. Spivak, J. Organomet. Chem., 2006, 691, 4147.
(a) D.B. Grotjahn, Chem. Eur. J., 2005, 11, 7146; (b) D.B. Grotjahn, V. Miranda-Soto, E.J.
Kragulj, D.A. Lev, G. Erdogan, X. Zeng and A.L. Cooksy, J. Am. Chem. Soc., 2008, 130,
20; (c) D.B. Grotjahn, Dalton Trans., 2008, 6497.
31.
32.
For other examples of intramolecular attack occurring on vinylidene ligands, see: (a) R.D.
Adams, A. Davison and J.P. Selegue, J. Am. Chem. Soc., 1979, 101, 7232; (b) M.P.
Gamasa, J. Gimeno, E. Lastra and B.M. Martín, J. Organomet. Chem., 1992, 429, C19; (c)
Y.-S. Yen, Y.-C. Lin, Y.-H. Liu and Y. Wang, Organometallics, 2007, 26, 1250.
Although we did not pursue the full assignment of complexes 6-9 as either E or Z using
solution methods, a partial X-ray structure determination of complex 8 not only confirmed
that ring-opening had occurred to form the five-membered ring vinylidene insertion
product, but also that the connectivity about the double bond was E. Unfortunately,
extensive solvent disorder prevented the complete solution of the structure.
M.I. Bruce, B.C. Hall, N.N. Zaitseva, B.W. Skelton and A.H. White, J. Chem. Soc., Dalton
Trans., 1998, 1793.
33.
34.
35.
A.B. Pangborn, M.A. Giardello, R.H. Grubbs, R.K. Rosen and F.J. Timmers,
Organometallics, 1996, 15, 1518.

ACCEPTED MANUSCRIPT
36.
37.
F.L. Joslin, J.T. Mague and D.M. Roundhill, Organometallics, 1991, 10, 521.
M.S. Chinn and D.M. Heinekey, J. Am. Chem. Soc., 1990, 112, 5166.

ACCEPTED MANUSCRIPT
Caption for Figure 1:
Figure 1. Molecular structure of complex 2 (hydrogen atoms omitted for clarity). Selected bond
lengths (Å) and angles (°): Ru(1)-P(1), 2.342(2); Ru(1)-P(2), 2.316(2); Ru(1)-N(1), 2.164(4);
Ru(1)-C(1), 2.233(7); Ru(1)-C(2), 2.217(7); Ru(1)-C(3), 2.178(8); Ru(1)-C(4), 2.167(8); Ru(1)-
C(5), 2.193(6); P(1)-C(6), 1.824(6); P(1)-C(6)-N(1), 104.4(4); P(1)-C(6)-N(2), 142.0(4); N(1)-
Ru(1)-P(1), 67.6(1); P(2)-Ru(1)-N(1), 90.9(1); P(2)-Ru(1)-P(1), 97.89(5).

ACCEPTED MANUSCRIPT
Captions for Schemes 1-6:
Scheme 1. Synthesis of ligand 1.
Scheme 2. Synthesis of complexes 2 and 3.
Scheme 3. Hemilabile behaviour of ligand 1.
Scheme 4. Synthesis of the E- and Z-isomers of complex 6.
Scheme 5. Possible mechanism for the synthesis of complexes 6-9.
Scheme 6. Alternate synthetic route to complex 8.