Pincer phosphine complexes of ruthenium: Formation of Ru(P-O-P)(PPh 3)HCl (P-O-P = xantphos, DPEphos, (Ph2PCH 2CH2)2O) and Ru(dppf)(PPh3)HCl and characterization of cationic dioxygen, dihydrogen, dinitrogen, and arene coordinated phosphine products

Article abstract of DOI:10.1021/ic100438d

Treatment of Ru(PPh₃)₃HCl with the pincer phosphines 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos), bis(2- diphenylphosphinophenyl)ether (DPEphos), or (Ph₂PCH ₂CH₂)₂O affords Ru(P-O-P)(PPh₃)HCl (xantphos, 1a; DPEphos, 1b; (Ph₂PCH₂CH₂) ₂O, 1c). The X-ray crystal structures of 1a-c show that all three P-O-P ligands coordinate in a tridentate manner through phosphorus and oxygen. Abstraction of the chloride ligand from 1a-c by NaBAr₄^F (BAr₄^F = B(3,5-C₆H₃(CF ₃)₂)₄) gives the cationic aqua complexes [Ru(P-O-P)(PPh₃)(H₂O)H]BAr₄^F (3a-c). Removal of chloride from 1a by AgOTf yields Ru(xantphos)(PPh₃)H(OTf) (2a), which reacts with water to form [Ru(xantphos)(PPh₃)(H ₂O)H](OTf). The aqua complexes 3a-b react with O₂ to generate [Ru(xantphos)(PPh₃)(η²-O₂)H] BAr₄^F (5a) and [Ru(DPEphos)(PPh₃) (η²-O₂)H]BAr₄^F (5b). Addition of H₂ or N₂ to 3a-c yields the thermally unstable dihydrogen and dinitrogen species [Ru(P-O-P)(PPh₃)(η²-H ₂)H]BAr₄^F (6a-c) and [Ru(P-O-P)(PPh ₃)(N₂)H]BAr₄^F (7a-c), which have been characterized by multinuclear NMR spectroscopy at low temperature. Ru(PPh₃)₃HCl reacts with 1,1′-bis(diphenylphosphino) ferrocene (dppf) to give the 16-electron complex Ru(dppf)(PPh₃)HCl (1d), which upon treatment with NaBAr₄^F, affords [Ru(dppf){(η⁶-C₆H₅)PPh₂}H] BAr₄^F (8), in which the PPh₃ ligand binds η⁶ through one of the PPh₃ phenyl rings. Reaction of 8 with CO or PMe₃ at elevated temperatures yields the 18-electron products [Ru(dppf)(PPh₃)(CO)₂H]BAr^F₄ (9) and [Ru(PMe₃)₅H]BAr₄^F (10).

Full text of DOI:10.1021/ic100438d

7244 Inorg. Chem. 2010, 49, 7244–7256
DOI: 10.1021/ic100438d
Pincer Phosphine Complexes of Ruthenium: Formation of Ru(P-O-P)(PPh3)HCl
(P-O-P = xantphos, DPEphos, (Ph2PCH2CH2)2O) and Ru(dppf)(PPh3)HCl and
Characterization of Cationic Dioxygen, Dihydrogen, Dinitrogen, and Arene
Coordinated Phosphine Products
Araminta E. W. Ledger,† Aitor Moreno,§ Charles E. Ellul,‡ Mary F. Mahon,‡ Paul S. Pregosin,§
Michael K. Whittlesey,*,† and Jonathan M. J. Williams†
†Department of Chemistry, and ‡X-ray Crystallographic Unit, University of Bath, Claverton Down, Bath BA2
§
€
7AY, U.K., and Laboratory of Inorganic Chemistry, ETHZ Honggerberg CH-8093 Zurich, Switzerland
Received March 5, 2010
Treatment of Ru(PPh3)3HCl with the pincer phosphines 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene
(xantphos), bis(2-diphenylphosphinophenyl)ether (DPEphos), or (Ph2PCH2CH2)2O affords Ru(P-O-P)(PPh3)HCl
(xantphos, 1a; DPEphos, 1b; (Ph2PCH2CH2)2O, 1c). The X-ray crystal structures of 1a-c show that all three
P-O-P ligands coordinate in a tridentate manner through phosphorus and oxygen. Abstraction of the chloride ligand
F
F
from 1a-c by NaBAr4 (BAr4 = B(3,5-C6H3(CF3)2)4) gives the cationic aqua complexes [Ru(P-O-P)-
(PPh3)(H2O)H]BAr4F (3a-c). Removal of chloride from 1a by AgOTf yields Ru(xantphos)(PPh3)H(OTf) (2a), which
reacts with water to form [Ru(xantphos)(PPh3)(H2O)H](OTf). The aqua complexes 3a-b react with O2 to generate
[Ru(xantphos)(PPh3)(η2-O2)H]BAr4F (5a) and [Ru(DPEphos)(PPh3)(η2-O2)H]BAr4F (5b). Addition of H2 or N2 to
3a-c yields the thermally unstable dihydrogen and dinitrogen species [Ru(P-O-P)(PPh3)(η2-H2)H]BAr4F (6a-c)
and [Ru(P-O-P)(PPh3)(N2)H]BAr4F (7a-c), which have been characterized by multinuclear NMR spectroscopy at
low temperature. Ru(PPh3)3HCl reacts with 1,10-bis(diphenylphosphino)ferrocene (dppf) to give the 16-electron
complex Ru(dppf)(PPh3)HCl (1d), which upon treatment with NaBAr4 , affords [Ru(dppf){(η6-C6H5)PPh2}H]BAr4
F
F
(8), in which the PPh3 ligand binds η6 through one of the PPh3 phenyl rings. Reaction of 8 with CO or PMe3 at elevated
temperatures yields the 18-electron products [Ru(dppf)(PPh3)(CO)2H]BArF4 (9) and [Ru(PMe3)5H]BAr4F (10).
Introduction
metal oxidation states,2 or afford metal complexes capable of
either activating inert bonds3 or bringing about novel cata-
lytic transformations.4 The most commonly encountered
linker groups consist of either a metalated aryl ring in the
anionic PCP or POCOP ligands (Chart 1) or a neutral donor
such as a pyridine, which affords the general class of
Tridentate phosphorus based pincer ligands containing
two phosphines and a central linker group have become
increasingly popular in recent years1 for their ability to help
stabilize unusual classes of ancillary ligands and less common
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r
pubs.acs.org/IC
Published on Web 06/24/2010
2010 American Chemical Society

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7245
Chart 1
activation of alcohols by reversible hydrogen transfer.10 Both
sets of compounds are coordinatively saturated, and conse-
quently exhibit bidentate (“O out”) coordination of the
xantphos ligands. In efforts to further investigate the coordi-
nation chemistry of ruthenium xantphos and related P-O-P
complexes,8,11 we now describe the reactivity of the tridentate
(“O in”) cationic aqua species[Ru(P-O-P)(PPh3)(H2O)H]þ
(P-O-P = xantphos, DPEphos, (Ph2PCH2CH2)2O) with
O2, H2, and N2. The role played by oxygen coordination is
highlighted by the different reactivity found with the bident-
ate ligand 1,10-bis(diphenylphosphino)ferrocene (dppf).
uncharged PNP ligands also shown in Chart 1. In the former
group, the linker usually remains firmly coordinated to the
metal center at all times, whereas in the latter case, temporary
dissociation of either the linker or, alternatively, one of the
phosphine arms can result in hemilabile behavior.
Experimental Section
Neutral ligands based on a P-O-P motif are less com-
mon, despite the fact that the weak OfM interaction ex-
pected with a soft transition metal should make such ligands
capable of both tridentate (“O in”) and bidentate (“O out”)
coordination modes. The most well-known of the P-O-P
systems are the xanthene based ligands, such as xantphos
(Chart 1),5 which in the vast majority of cases, coordinate in a
bidentate (“O out”) fashion. There are very few fully char-
acterized examples of tridentate xanthene type ligands,6-8
despite this binding mode being proposed to have relevance
in a number of catalytic processes utilizing xantphos or other
P-O-P type ligands.9
General Comments. All manipulations were carried out using
standard Schlenk, high vacuum, and glovebox techniques.
Solvents were purified using MBraun SPS and Innovative
Technologies solvent systems (dichloromethane, toluene, tetra-
hydrofuran (THF)) or by distillation under argon from sodium
benzophenone ketyl (benzene, hexane) or Mg/I2 (ethanol). Deu-
terated solvents (Aldrich) were vacuum transferred from potas-
sium (C6D6, THF-d8) or calcium hydride (CD2Cl2). Literature
methods (or slight variations of) were used for the preparation
of Ru(PPh3)3HCl12 and (Ph2PCH2CH2)O.7,13 Xantphos and
DPEphos were purchased from Sigma-Aldrich and used as
received. NMR spectra were recorded on Bruker Avance 400,
500, and 700 MHz spectrometers. 1H and 13C{1H} spectra were
referenced to the solvent as follows: δ 7.15 and δ 128.0 (C6D6); δ
5.32 and δ 53.7 (CD2Cl2); δ 3.58 and 25.4 (THF-d8). 31P{1H}
NMR chemical shifts were referenced externally to 85% H3PO4
(δ 0.0). 15N shifts are given relative to nitromethane at δ=0.
Coupling constants for the spectra marked 31P{1H}* for 6b and
7b were determined by simulations performed using g-NMR.14
IR spectra were recorded on a Nicolet Nexus FTIR spectro-
meter. Mass spectra were recorded using a microTOF electro-
spray time-of-flight (ESI-TOF) mass spectrometer (Bruker
Daltonik GmbH) coupled to an Agilent 1200 LC system
(Agilent Technologies). Elemental analyses were performed by
Elemental Microanalysis Ltd., Okehampton, Devon, U.K. or
the Elemental Analysis Service, London Metropolitan Univer-
sity, London, U.K.
We have reported the use of Ru(xantphos)(PPh3)(CO)H2
and Ru(xantphos)(NHC)(CO)H2 (NHC = N-heterocyclic
carbene) in the “borrowing hydrogen” methodology for the
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2005, 4450–4452. (e) Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. Angew.
Chem., Int. Ed. 2006, 45, 1113–1115. (f) Goldman, A. S.; Roy, A. H.; Huang, Z.;
Ahuja, R.; Schinski, W.; Brookhart, M. Science 2006, 312, 257–261.
(g) Gunanathan, C.; Shimon, L. J. W.; Milstein, D. J. Am. Chem. Soc. 2009,
131, 3146–3147.
(5) For reviews, see: (a) Dierkes, P.; van Leeuwen, P. W. N. M. J. Chem.
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904. (d) Freixa, Z.; van Leeuwen, P. W. N. M. Dalton Trans. 2003, 1890–1901.
Ru(xantphos)(PPh3)HCl (1a). Ru(PPh3)3HCl(0.092g, 0.1mmol)
and xantphos (0.069 g, 0.12 mmol) were refluxed together in dry
THF (10 mL) for 3 h to give a bright orange solution. After removal
of the solvent, the product was washed in hexane (3 ꢀ 10 mL) and
recrystallized from benzene/hexane to give orange needle-like crys-
tals (0.086 g, 88%). Selected 1H NMR (C6D6, 400 MHz, 298 K): δ
-16.22 (dt, 2JHP =27.2Hz, 2JHP = 23.9 Hz, 1H, RuH), 1.25 (s, 3H,
C(CH3)2), 1.30 (s, 3H, C(CH3)2). 31P{1H} (C6D6, 162 MHz, 298 K):
δ 75.2 (t, 2JPP = 33 Hz), 46.7 (d, 2JPP = 33 Hz). Anal. Calcd (%) for
ꢀ
(e) Birkholz (nee Gensow), M.-N.; Freixa, Z.; van Leeuwen, P. W. N. M. Chem.
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(6) (a) Alcock, N. W.; Brown, J. M.; Jeffery, J. C. J. Chem. Soc., Dalton
Trans. 1976, 583–588. (b) Steffey, B. D.; Miedaner, A.; Maciejewski-Farmer,
M. L.; Berantis, P. R.; Herring, A. M.; Allured, V. S.; Carperos, V.; DuBois, D. L.
Organometallics 1994, 13, 4844–4855. (c) Kataoka, Y.; Tsuji, Y.; Matsumoto, O.;
Ohashi, M.; Yamagata, T.; Tani, K. J. Chem. Soc., Chem. Commun. 1995, 2099–
2100. (d) Moxham, G. L.; Randell-Sly, H.; Brayshaw, S. K.; Weller, A. S.; Willis,
M. C. Chem.;Eur. J. 2008, 14, 8383–8397.
C57H48OP3ClRu 2C6H6 (1134.66): C 73.04, H 5.33; found: C 72.63,
H 5.41.
3
(7) Bolzati, C.; Boschi, A.; Uccelli, L.; Tisato, F.; Refosco, F.; Cagnolini,
A.; Duatti, A.; Prakash, S.; Bandolini, G.; Vittadini, A. J. Am. Chem. Soc.
2002, 124, 11468–11479.
Ru(DPEphos)(PPh3)HCl (1b). As for 1a by refluxing Ru-
(PPh3)3HCl (0.092 g, 0.1 mmol) and DPEphos (0.162 g, 0.3 mmol)
(8) Major, Q.; Lough, A. J.; Gusev, D. G. Organometallics 2005, 24,
2492–2501.
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R. L.; Weller, A. S.; Willis, M. C. Angew. Chem., Int. Ed. 2006, 45, 7618–
7622. (b) Ohshima, T.; Miyamoto, Y.; Ipposhi, J.; Nakahara, Y.; Utsunomiya, M.;
Mashima, K. J. Am. Chem. Soc. 2009, 131, 14317–14328.
(10) (a) Slatford, P. A.; Whittlesey, M. K.; Williams, J. M. J. Tetrahedron
Lett. 2006, 47, 6787–6789. (b) Pridmore, S. J.; Slatford, P. A.; Williams, J. M. J.
Tetrahedron Lett. 2007, 48, 5111–5114. (c) Anand, N.; Owston, N. A.; Parker,
A. J.; Slatford, P. A.; Williams, J. M. J. Tetrahedron Lett. 2007, 48, 7761–7763.
(d) Pridmore, S. J.; Slatford, P. A.; Taylor, J. E.; Whittlesey, M. K.; Williams,
J. M. J. Tetrahedron 2009, 65, 8981–8986. (e) Owston, N. A.; Nixon, T. D.;
Parker, A. J.; Whittlesey, M. K.; Williams, J. M. J. Synthesis 2009, 1578–1581.
(f) Ledger, A. E. W.; Slatford, P. A.; Lowe, J. P.; Mahon, M. F.; Whittlesey, M. K.;
Williams, J. M. J. Dalton Trans. 2009, 716–722. (g) Ledger, A. E. W.; Mahon,
M. F.; Whittlesey, M. K.; Williams, J. M. J. Dalton Trans. 2009, 6941–6947.
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Chaudret, B. Chem. Commun. 1997, 373–374. (b) Lenero, K. A.; Kranenburg,
M.; Guari, Y.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.; Sabo-Etienne, S.;
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12, 868–871.
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7246 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
in THF for 1.5 h. After washing with hexane, recrystallization
from CH2Cl2/hexane gave orange needle-like crystals of the pro-
duct in 65% yield (0.061 g). Selected 1H NMR (CD2Cl2, 400 MHz,
[Ru(xantphos)(PPh3)(MeCN)H]BArF (4a). A CD2Cl2 solu-
tion of 1a (0.010 g, 0.01 mmol) and NaBAr4 (0.009 g, 0.011
4
F
mmol) was left to stand in an NMR tube fitted with a resealable
J. Young’s PTFE valve at room temperature for 15 h. MeCN
(0.003 mL, 0.05 mmol) was then added to the solution via
2
2
298 K): δ -16.34 (dt, JHP = 27.6 Hz, JHP = 23.6 Hz, 1H,
2
RuH). 31P{1H} (CD2Cl2, 162 MHz, 298 K): δ 75.3 (t, JPP
=
30.9 Hz), 46.7 (br s). 31P{1H} (CD2Cl2, 162 MHz, 233 K): δ 75.0
(t, 2JPP = 31 Hz), 39.7 (dd, 2JPP = 285 Hz, 2JPP = 31 Hz), 30.8
(dd, 2JPP=285 Hz, 2JPP=31 Hz). Anal. Calcd (%) for C54H44-
syringe. The product, [Ru(xantphos)(PPh3)(MeCN)H]BArF
4
(4a), was spectroscopically characterized. Selected 1H NMR
2
(CD2Cl2, 500 MHz, 298 K): δ -13.39 (dt, JHP = 27.0 Hz,
2JHP = 19.1 Hz, 1H, RuH), 1.36 (s, 3H, NC-CH3). 31P{1H}
(CD2Cl2, 202 MHz, 298 K): δ 75.8 (br), 51.2 (d, 2JPP = 30 Hz).
Selected 13C{1H} NMR (CD2Cl2, 126 MHz, 298 K): δ 2.9 (s,
NC-CH3), 121.8 (s, NC-CH3). IR (nujol, cm-1): 2241 (νCN).
Comparable spectroscopic data was recorded for the corre-
sponding triflate salt, which was prepared by addition of MeCN
(0.003 mL, 0.05 mmol) to a CD2Cl2 solution of 2a (0.011 g, 0.01
mmol) in a J. Youngs NMR tube. Selected 1H NMR (CD2Cl2,
500 MHz, 298 K): δ -13.42 (dt, 2JHP = 27.0 Hz, 2JHP = 19.1
Hz, 1H, RuH), 1.42 (s, 3H, NC-CH3). 31P{1H} (CD2Cl2, 202
MHz, 298 K): δ 76.1 (br), 51.4 (d, 2JPP = 30 Hz).
OP3ClRu 0.5CH2Cl2 (885.79): C 66.74, H 4.62; found: C 66.77,
3
H 4.82.
Ru((Ph2PCH2CH2)2O)(PPh3)HCl (1c). As for 1a by reflux-
ing Ru(PPh3)3HCl (0.092 g, 0.1 mmol) and (Ph2PCH2CH2)2O
(0.049 g, 0.12 mmol) in THF for 0.5 h. After hexane washing, re-
crystallization from CH2Cl2/hexane gave orange crystals of the
1
product in 60% yield (0.051 g). Selected H NMR (CD2Cl2,
500 MHz, 298 K): δ -17.54 (dt, 2JHP = 28.5 Hz, 2JHP = 21.7 Hz,
1H, RuH), 2.48 (m, 2H, PCH2), 2.72 (m, 2H, PCH2), 3.37 (m,
2H, OCH2), 4.11 (m, 2H, OCH2). 31P{1H} (CD2Cl2, 202 MHz,
298 K): δ 71.0 (t, 2JPP = 32 Hz), 42.3 (d, 2JPP = 32 Hz). Anal.
[Ru(xantphos)(PPh3)(η2-O2)H]BAr4 (5a). A CH2Cl2 solu-
F
Calcd (%) for C46H44OP3ClRu 0.75CH2Cl2 (906.00): C 61.98,
H 5.06; found: C 61.98, H 5.24.
3
tion (10 mL) of 1a (0.120 g, 0.12 mmol) and NaBAr4F (0.110 g,
0.14 mmol) was stirred in an ampule fitted with a J. Young’s
PTFE tap at room temperature for 15 h and then filtered to
remove the white precipitate of NaCl. The filtrate was opened to
air and left stirring for 10 min, before the solvent was removed in
vacuo. The resulting solid was washed with hexane (10 mL) and
recrystallized from CH2Cl2/hexane to afford brown crystals of
5a (0.109 g, 49%). Selected 1H NMR (CD2Cl2, 400 MHz,
Ru(xantphos)(PPh3)H(OTf) (2a). A CH2Cl2 solution (10 mL)
of 1a (0.200 g, 0.20 mmol) and AgOTf (0.086 g, 0.22 mmol) was
stirred in an ampule fitted with a J. Young’s PTFE tap at room
temperature for 15 h and then filtered to remove a gray
precipitate of AgCl. The solvent was reduced by half and layered
with hexane to afford yellow crystals of 2a (0.132 g, 59%).
1
Selected H NMR (CD2Cl2, 400 MHz, 315 K): δ -22.27 (dt,
2JHP = 31.0 Hz, 2JHP = 22.6 Hz, 1H, RuH). 31P{1H} (CD2Cl2,
162 MHz, 315 K): δ 68.9 (t, 2JPP = 31 Hz), 44.9 (d, 2JPP = 31
Hz). 19F NMR (CD2Cl2, 376 MHz, 298 K): δ -78.8 (s, OTf).
Anal. Calcd (%) for C58H48O4P3SF3Ru (1092.07): C 63.79, H
4.43; found: C 63.66, H 4.30.
2
2
298 K): δ -1.48 (dt, JHP = 29.4 Hz, JHP = 27.2 Hz, 1H,
RuH), 1.45 (s, 3H, C(CH3)2), 1.87 (s, 3H, C(CH3)2). 31P{1H}
2
(CD2Cl2, 162 MHz, 298 K): δ 48.2 (t, JPP = 19 Hz), 44.4 (d,
2JPP = 19 Hz). Anal. Calcd (%) for C89H60BO3F24P3Ru
(1838.17): C 58.15, H 3.29; found: C 57.98, H 3.10. ESI-TOF
MS: [M]þ m/z = 975.1931 (theoretical 975.1870).
[Ru(xantphos)(PPh3)(H2O)H]BAr4F (3a). A CD2Cl2 solution
of 1a (0.010 g, 0.01 mmol) and NaBAr4F (0.009 g, 0.011 mmol)
was left to stand in an NMR tube fitted with a resealable
J. Young’s PTFE valve at room temperature for 15 h to afford
[Ru(DPEphos)(PPh3)(η2-O2)H]BAr4F (5b). As for 5a using 1b
(0.100 g, 0.11 mmol) and NaBAr4F (0.095 g, 0.12 mmol). After
exposure to air and removal of the solvent, the resulting solid
was washed twice with hexane (10 mL) and sonicated before
being dried overnight under vacuum to give 5b as a tan solid
(0.090 g, 48%). Larger scale recrystallization proved difficult
because of facile overoxidation of the complex in solution.
1
the product. Selected H NMR (CD2Cl2, 400 MHz, 298 K): δ
2
2
-19.67 (dt, JHP = 29.4 Hz, JHP = 18.6 Hz, 1H, RuH).
31P{1H} (CD2Cl2, 162 MHz, 298 K): δ 73.2 (t, 2JPP = 28 Hz),
46.9 (d, JPP = 28 Hz). ESI-TOF MS: [M-H2O]þ m/z =
943.1993 (theoretical 943.1972).
2
1
Selected H NMR (CD2Cl2, 400 MHz, 298 K): δ -2.01 (dt,
2JHP = 32.0 Hz, 2JHP = 30.4 Hz, 1H, RuH). 31P{1H} (CD2Cl2,
The corresponding triflate salt [Ru(xantphos)(PPh3)(H2O)-
H]OTf was prepared by stirring 1a (0.098 g, 0.10 mmol) with
AgOTf (0.043 g, 0.11 mmol) in CH2Cl2 (10 mL) for 15 h. After
filtration to remove AgCl, degassed H2O (0.027 mL, 0.001 mol)
was added and the suspension stirred for 30 min. The volume of
solvent was reduced by half and a layer of hexane added. This
afforded yellow crystals, at least some of which corresponded to
[Ru(xantphos)(PPh3)(H2O)H]OTf on the basis of X-ray diffrac-
tion.15 NMR analysis of the crystalline material as a whole
showed it to consist of both the aqua complex (0.045 g, 41%)
and [Ru(xantphos)(PPh3)(η2-O2)H]OTf (0.011 g, 10%). The
latter species was always formed as a side product in varying
amounts, and could not be separated. This excluded the possi-
bility of determining CHN analysis of the aqua complex.
[Ru(DPEphos)(PPh3)(H2O)H]BAr4FF (3b). As for 3a, but with
1b (0.009 g, 0.01 mmol) and NaBAr4 (0.009 g, 0.011 mmol).
2
2
162 MHz, 298 K): δ 41.4 (t, JPP = 19 Hz), 36.2 (d, JPP
=
19 Hz). ESI-TOF MS: [M]þ m/z = 935.1600 (theoretical
935.1556).
[Ru((Ph2PCH2CH2)2O)(PPh3)(η2-O2)H]BAr4F (5c). A CD2Cl2
solution of 1c (0.008 g, 0.01 mmol) and NaBAr4F (0.009 g, 0.011) in
a resealable J. Young’s NMR tube was prepared at room tem-
perature, and after being left for 15 h, exposed to air, which resulted
in an rapid color change from yellow to yellow-green. NMR
F
spectra of [Ru((Ph2PCH2CH2)2O)(PPh3)(η2-O2)H]BAr4 (5c)
were run immediately to minimize the degradation of the complex.
Selected 1H NMR (CD2Cl2, 400 MHz, 298 K): δ -2.88 (dt, 2JHP
=
29.6 Hz, 2JHP = 25.9 Hz, 1H, RuH), 2.42-2.61 (m, 4H, PCH2),
3.48 (m, 2H, OCH2), 3.74 (m, 2H, OCH2). 31P{1H} (CD2Cl2,
162 MHz, 298 K): δ 48.2 (t, 2JPP=19 Hz), 45.8 (d, 2JPP = 19 Hz).
F
[Ru(xantphos)(PPh3)(η2-H2)H]BAr4 (6a). A CD2Cl2 solu-
1
F
tion of 1a (0.010 g, 0.01 mmol) and NaBAr4 (0.009 g, 0.011
Selected H NMR (CD2Cl2, 400 MHz, 298 K): δ -18.67 (dt,
2JHP = 31.4 Hz, 2JHP = 20.2 Hz, 1H, RuH). 31P{1H} (CD2Cl2,
162 MHz, 298 K): δ 72.0 (br s), 45.1 (br s).
mmol) was left to stand in an NMR tube fitted with a resealable
J. Young’s PTFE valve at room temperature for 15 h. The
solution was freeze-pump-thaw degassed three times and
placed under 1 atm of H2 to give a mixture of [Ru(xantphos)-
(PPh3)(η2-H2)H]BAr4F (6a) and unreacted 3a in a ratio of 3.1:1
at 180 K. Selected 1H NMR (CD2Cl2, 400 MHz, 180 K): δ -8.79
(dt, 2JHP = 22.4 Hz, 2JHP = 19.1 Hz, 1H, RuH), -0.95 (broad s,
2H, η2-H2), 1.42 (s, 3H, C(CH3)2), 1.61 (s, 3H, C(CH3)2).
31P{1H} (CD2Cl2, 162 MHz, 180 K): δ 67.6 (t, 2JPP = 28 Hz),
51.9 (d, 2JPP = 28 Hz).
[Ru((Ph2PCH2CH2)2O)(PPh3)(H2O)H]BAr4F (3c). As for 3a,
but with 1c (0.008 g, 0.01 mmol) and NaBAr4 (0.009 g, 0.011).
=
F
Selected 1HNMR(CD2Cl2, 400MHz, 298K):δ-21.05 (dt, 2JHP
30.3 Hz, 2JHP = 18.1 Hz, 1H, RuH). 31P{1H} (CD2Cl2, 162 MHz,
298 K): δ 72.4.2 (t, 2JPP = 29 Hz), 47.8 (d, 2JPP = 29 Hz).
(15) The X-ray structure of this complex is provided in the Supporting
Information.

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7247
[Ru(DPEphos)(PPh3)(η2-H2)H]BAr4F (6b). As for 6a, butwith
1b (0.009 g, 0.01 mmol) and NaBAr4 (0.009 g, 0.011 mmol) to
suspension was filtered by cannula to remove NaCl, and the
filtrate reduced to dryness. The resulting orange solid was
washed with hexane (2 ꢀ 10 mL) and recrystallized from CH2Cl2/
hexane (Yield: 0.178 g, 52%). Selected 1H NMR (CD2Cl2,
400 MHz, 298 K): δ -9.32 (dt, 2JHP = 38.8 Hz, JHP = 7.0 Hz,
1H, RuH), 4.20 (m, 2H, C5H4), 4.32 (m, 2H, C5H4), 4.36 (m, 4H,
C5H4), 4.72 (m, 2H, η6-C6H5PPh2), 4.84 (m, 2H, η6-C6H5PPh2),
6.02 (m, 1H, (η6-C6H5)PPh2). 31P{1H} (CD2Cl2, 162 MHz, 298
K): δ 50.2 (s, Pdppf), -8.1 (s, (η6-C6H5)PPh2). Selected 13C{1H}
(CD2Cl2, 100 MHz, 298 K): δ 73.9 (m, Cdppf), 75.6 (m, Cdppf),
76.0 (m, Cdppf), 94.6 (dt, JCP = 15.7 Hz, JCP = 3.1 Hz, η6-
C6H5PPh2), 97.1 (m, η6-C6H5PPh2), 96.3 (s, η6-C6H5PPh2),
109.7 (dt, JCP = 27.4 Hz, JCP = 2.1 Hz, η6-C6H5PPh2). Anal.
F
F
afford a mixture of [Ru(DPEphos)(PPh3)(η2-H2)H]BAr4 (6b)
and 3b in a ratio of 6.1:1 at 195 K. Selected 1H NMR (CD2Cl2,
400 MHz, 195 K): δ -7.95 (dt, 2JHP = 22.8 Hz, 2JHP = 19.4 Hz,
1H, RuH), -0.25 (broad s, 2H, η2-H2). 31P{1H}* (CD2Cl2, 162
MHz, 195 K): δ 69.2 (t, 2JPP = 26 Hz), 47.1 (dd, 2JPP = 226 Hz,
2JPP = 26 Hz), 46.2 (dd, 2JPP = 226 Hz, 2JPP = 26 Hz).
F
[Ru((Ph2PCH2CH2)2O)(PPh3)(η2-H2)H]BAr4 (6c). As for
F
6a, but with 1c (0.008 g, 0.01 mmol) and NaBAr4 (0.009 g,
0.011 mmol) to afford a mixture of [Ru((Ph2PCH2CH2)2O)-
(PPh3)(η2-H2)H]BAr4F (6c) and unreacted 3c in a ratio of 4.4:1
at 195 K. Selected 1H NMR (CD2Cl2, 400 MHz, 195 K): δ -9.16
(dt, 2JHP = 23.6 Hz, 2JHP = 16.2 Hz, 1H, RuH), -1.91 (broad s,
2H, η2-H2), 2.35 (m, 2H, PCH2), 2.60 (m, 2H, PCH2), 3.17 (m,
2H, OCH2), 3.71 (m, 2H, OCH2). 31P{1H} (CD2Cl2, 162 MHz,
195 K): δ 66.9 (t, 2JPP = 27 Hz), 56.2 (d, 2JPP = 27 Hz).
[Ru(xantphos)(PPh3)(N2)H]BAr4F (7a). A CD2Cl2 solution of
1a (0.010 g, 0.01 mmol) and NaBAr4F (0.009 g, 0.011 mmol) was
left to stand in an NMR tube fitted with a resealable J. Young’s
PTFE valve at room temperature for 15 h. The solution was
freeze-pump-thaw degassed three times and placed under
1 atm of N2 to give a mixture of [Ru(xantphos)(PPh3)(N2)-
Calcd (%) for C84H44BF24P3FeRu CH2Cl2 (1781.98): C 54.69,
3
H 3.13; found: C 54.77, H 2.91.
[Ru(dppf)(PPh3)(CO)2H]BArF4 (9). A solution of 8 (0.100 g,
0.057 mmol) in CH2Cl2 (10 mL) in an ampule fitted with a
J. Young’s PTFE valve was freeze-pump-thaw degassed three
times, placed under 1 atm CO and heated at reflux for 15 h. After
cooling, the solvent was removed, and the resulting orange solid
washed with hexane (2 ꢀ 10 mL) to give 9 as a yellow solid,
which was spectroscopically characterized (Yield: 0.058 g,
56%). Selected 1H NMR (CD2Cl2, 400 MHz, 298 K): δ -8.56
2
2
2
F
(ddd, JHP = 62.2 Hz, JHP = 24.3 Hz, JHP = 19.3 Hz, 1H,
RuH: 1H{31P} NMR spectrum recorded with 13CO labeling: δ
-8.56 (t, 2JHC = 5.6 Hz)), 4.25 (s, 2H, C5H4), 4.49 (s, 2H, C5H4),
4.52 (s, 2H, C5H4), 4.62 (m, 2H, C5H4). 31P{1H} (CD2Cl2,
H]BAr4 (7a) and unreacted 3a in a ratio of 6.7:1 at 180 K.
1
Selected H NMR (CD2Cl2, 400 MHz, 180 K): δ -11.72 (dt,
2JHP = 26.0 Hz, 2JHP = 16.5 Hz, 1H, RuH: 1H{31P} NMR spec-
trum recorded with 15N labeling: δ -11.76 (d, 2JHN = 17.9 Hz)),
1.46 (s, 3H, C(CH3)2), 1.66 (s, 3H, C(CH3)2). 31P{1H} (CD2Cl2,
2
162 MHz, 298 K): δ 36.8 (dd, JPP = 178 Hz, 2JPP = 13 Hz),
32.3 (dd, 2JPP = 178 Hz, 2JPP = 17 Hz), 20.4 (dd, 2JPP = 17 Hz,
2JPP = 13 Hz). Selected 13C{1H} (CD2Cl2, 100 MHz, 298 K):
δ 200.2 (dt, 2JCP = 14.1 Hz, 2JCP = 11.1 Hz, CO). IR (CH2Cl2,
cm-1): 2001 (νCO). ESI-TOF MS: [M]þ m/z = 975.0980 (the-
oretical 975.0958).
2
2
162 MHz, 180 K): δ 68.2 (t, JPP = 27 Hz), 47.8 (d, JPP
=
27 Hz). 15N{1H} (CD2Cl2, 400 MHz, 180 K): δ -88.7 (s, R-N),
-57.6 (s, β-N).
[Ru(DPEphos)(PPh3)(N2)H]BAr4 (7b). As for 7a, but with
F
1b (0.009 g, 0.01 mmol) and NaBAr4F (0.009 g, 0.011 mmol) to
F
F
give a mixture of [Ru(DPEphos)(PPh3)(N2)H]BAr4 (7b) and
[Ru(PMe3)5H]BAr4 (10). PMe3 (0.077 mL, 0.75 mmol)
1
unreacted 3b in a ratio of 4.5:1 at 180 K. Selected H NMR
was added by syringe to a THF (10 mL) solution of 8 (0.267 g,
0.15 mmol) in an ampule fitted with a J. Young’s PTFE valve,
and the reaction mixture heated at reflux for 3 h. After cooling,
the solvent was removed, and the resulting pale yellow solid
washed with benzene (2 ꢀ 10 mL) and recrystallized from THF/
hexane to afford 10 as clear needle-like crystals (0.100 g, 50%).
2
(CD2Cl2, 400 MHz, 180 K): δ -11.04 (dt, JHP = 26.7 Hz,
2JHP = 20.0 Hz, 1H, RuH: H{31P} NMR spectrum recorded
1
with 15N labeling: δ -11.06 (d, JHN = 16.9 Hz)). 31P{1H}*
2
(CD2Cl2, 162 MHz, 180 K): δ 65.4 (t, 2JPP = 27 Hz), 43.1 (dd,
=
2JPP = 241 Hz, 2JPP = 25 Hz), 41.7 (dd, 2JPP = 241 Hz, 2JPP
1H NMR (THF-d8, 500 MHz, 298 K): δ -11.35 (dquin, 2JHP
=
28 Hz). 15N{1H} (CD2Cl2, 400 MHz, 180 K): δ -82.6 (s, R-N),
-51.8 (s, β-N).
74.4 Hz, 2JHP = 25.3 Hz, 1H, RuH), 1.38 (d, 9H, 2JHP = 5.9 Hz,
PMe3), 1.54 (br s, 36H, PMe3). 31P{1H} (THF-d8, 201 MHz, 298
K): δ -23.2 (quint, 2JPP = 26 Hz), -9.9 (d, 2JPP = 26 Hz). Anal.
Calcd (%) for C47H58BF24P5Ru (1345.69): C 41.95, H 4.34;
found: C 41.86, H 4.28.
F
[Ru((Ph2PCH2CH2)2O)(PPh3)(N2)H]BAr4 (7c). As for 7a,
but with 1c (0.008 g, 0.01 mmol) and NaBAr4F (0.009 g, 0.011
mmol) to afford a mixture of [Ru((Ph2PCH2CH2)2O)(PPh3)-
(N2)H]BAr4F (7c) and unreacted 3c in a ratio of 2.4:1 at 195 K.
1
X-ray Crystallography. Single crystals of compounds for
1a-d, 2a, 3a, 5a, 5b, 8, and 10 were analyzed at using Mo(KR)
radiation. Data collection for 10 was also effected at 100 K on an
Oxford Diffraction Gemini diffractometer, whereas all other
data sets were collected at 150 K on a Nonius Kappa CCD
machine. Details of the data collections, solutions, and refine-
ments are given in Table 1. The structures were solved using
SHELXS-9716 and refined using full-matrix least-squares in
SHELXL-97.16
Selected H NMR (CD2Cl2, 400 MHz, 195 K): δ -12.06 (dt,
2
1
2JHP = 25.3 Hz, JHP = 16.6 Hz, 1H, RuH: H{31P} NMR
spectrum recorded with 15N labeling: δ -12.08 (d, 2JHN = 18.1
Hz)), 2.11 (m, 2H, P-CHH), 2.70 (m, 2H, P-CHH), 3.28 (m, 2H,
O-CHH), 3.87 (m, 2H, O-CHH). 31P{1H} (CD2Cl2, 162 MHz,
195 K): δ 67.2 (t, 2JPP = 27 Hz), 51.1 (d, 2JPP = 27 Hz). 15N{1H}
(CD2Cl2, 400 MHz, 195 K): δ -86.2 (s, R-N), -59.1 (s, β-N).
Ru(dppf)(PPh3)HCl (1d). As for 1a by refluxing Ru-
(PPh3)3HCl (0.092 g, 0.1 mmol) and dppf (0.055 g, 0.12 mmol)
in THF (10 mL) for 0.5 h. After hexane washing, recrystalliza-
tion from THF/hexane gave orange crystals of the product in
48% yield (0.046 g). Selected 1H NMR (THF-d8, 500 MHz, 298
K): δ -19.99 (dt, 2JHP = 29.9 Hz, 2JHP = 19.9 Hz, 1H, RuH),
4.16 (s, 2H, C5H4), 4.27 (s, 2H, C5H4), 4.30 (s, 2H, C5H4), 4.51 (s,
2H, C5H4). 31P{1H} (THF-d8, 162 MHz, 298 K): δ 64.9 (br s),
41.4 (t, 2JPP = 134 Hz). 213 K: δ 83.1 (br s), 48.4 (dd, 2JPP = 299
Refinements were generally straightforward, and hydride
˚
ligands, where located, were refined at a distance of 1.6 A from
the central ruthenium atom. The following points merit noting.
The structure of 1a was seen to contain two benzene molecules in
addition to 1 molecule of the ruthenium complex in the asym-
metric unit, while in 1b, two molecules of CH2Cl2 were in
evidence in the motif. Optimal refinement was achieved after
accounting for disorder of one chlorine in each solvent moiety.
A solvent fragment of dichloromethane (75% occupancy) was
found in 1c. In 1d, the asymmetric unit was found to contain
2
2
2
Hz, JPP = 30 Hz), 41.5 (dd, JPP = 294 Hz, JPP = 25 Hz).
Anal. Calcd (%) for C52H44P3ClFeRu 3C4H8O (1170.54): C
3
65.67, H 5.86; found: C 65.56, H 6.11.
[Ru(dppf)({η6-C6H5}PPh2)H]BAr4F (8). Complex 1d (0.095 g,
0.10 mmol) and NaBArF4 (0.089 g, 0.11 mmol) were charged to
an ampule fitted with a J. Young’s PTFE tap, dissolved in
CH2Cl2 (10 mL) and stirred at room temperature for 15 h. The
(16) Sheldrick, G. M. Acta Crystallogr. 1990, 467-473, A46. Sheldrick,
G. M. SHELXL-97, a computer program for crystal structure refinement;
€
€
University of Gottingen: Gottingen, Germany, 1997.

7248 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
Table 1. Crystal Data for Complexes 1a, 1b, 1c, 2a, 3a, 5a, 5b, 1d, 8, and 10
1a
1b
1c
2a
3a
5a
empirical formula
C69H60
ClOP3Ru
1134.60
C56H48Cl5
OP3Ru
1108.17
monoclinic
P21/a
C46.75H45.5
Cl2.5OP3Ru
905.94
C60.70H53.40Cl5.40
F3O4P3RuS
1321.30
triclinic
P1
C92.6H62BF24
O2P3Ru
1867.41
monoclinic
P21/a
C89.5H61BClF24
O3P3Ru
1880.62
monoclinic
P21/a
formula weight
crystal system
space group
monoclinic
P21/n
monoclinic
P21/n
˚
a/A
13.3340(1)
30.1610(3)
14.0980(2)
90
12.0690(1)
36.7400(3)
12.1330(1)
90
9.8590(1)
26.7330(4)
16.7610(3)
90
12.9730(1)
14.8850(1)
15.5800(2)
86.635(1)
84.018(1)
80.954(1)
2952.21(5)
2
18.4540(2)
20.4010(3)
22.4910(3)
90
13.2770(1)
40.2040(4)
17.2050(2)
90
˚
b/A
˚
c/A
R/deg
β/deg
γ/deg
96.471(1)
90
109.006(1)
90
103.583(1)
90
94.387(1)
90
97.14
90
3
˚
U/A
5633.62(11)
4
1.338
5086.66(7)
4
1.447
4293.98(11)
4
1.401
8442.60(19)
4
1.469
9112.55(16)
4
1.371
Z
Dc/g cm-3
μ/mm-1
F(000)
1.486
0.683
1347
0.455
2352
0.705
2264
0.667
1862
0.345
3774
0.349
3796
crystal size/mm
θ min., max for data collection 3.52, 30.07
0.45 ꢀ 0.40 ꢀ 0.25 0.32 ꢀ 0.20 ꢀ 0.12 0.25 ꢀ 0.07 ꢀ 0.07 0.30 ꢀ 0.25 ꢀ 0.25 0.25 ꢀ 0.15 ꢀ 0.07 0.30 ꢀ 0.15 ꢀ 0.05
3.55, 27.48
-15 e h e 15;
-47 e k e 47;
-15 e l e 15
50533
3.72, 27.49
-12 e h e 12;
-34 e k e 34;
-21 e l e 21
67435
3.55, 30.00
-18 e h e 18;
-20 e k e 20;
-21 e l e 21
67721
3.52, 25.03
-21 e h e 21;
-24 e k e 24;
-26 e l e 26
119161
3.52, 25.00
-15 e h e 15;
-47 e k e 47;
-20 e l e 20
126839
index ranges
-18 e h e 18;
-42 e k e 42;
-19 e l e 19
70022
reflections collected
independent reflections, Rint
reflections observed (>2σ)
data completeness
16368, 0.1263
9135
0.990
11498, 0.0656
9373
0.986
9827, 0.0538
8020
0.996
17100, 0.0424
14227
0.995
14858, 0.1470
11104
0.997
15997, 0.1394
10693
0.996
absorption correction
max., min transmission
data/restraints/parameters
goodness-of-fit n F2
multiscan
0.90, 0.78
16368/4/682
1.004
multiscan
0.94, 0.88
multiscan
multiscan
multiscan
multiscan
0.894, 0.829
9827/1/501
1.099
0.900, 0.801
17100/6/730
1.028
0.987, 0.559
14858/131/1210
1.034
0.973, 0.868
15997/199/1172
1.110
11498/1/614
1.018
final R1, wR2 [I >2σ(I)]
final R1, wR2 (all data)
largest diff. peak, hole/e A
0.0564, 0.1048
0.1363, 0.1295
1.471, -0.540
0.0432, 0.1038
0.0588, 0.1126
1.624, -1.343
0.0442, 0.1039
0.0605, 0.1109
1.417, -0.474
0.0433, 0.1108
0.0560, 0.1195
0.684, -0.521
0.0502, 0.1184
0.0761, 0.1382
0.684, -0.521
0.0963, 0.2347
0.1470, 0.2625
0.854, -0.704
-3
˚
5b
1d
8
10
empirical formula
formula weight
crystal system
space group
C86H56BF24O3P3Ru
1798.10
triclinic
C64H68ClFeO3P3Ru
1170.46
triclinic
C84H56BF24FeP3Ru
1781.93
C62.75H80.50B1.25F30OP6.25Ru1.25
1754.18
monoclinic
P21/c
tetragonal
P42/n
P1 (No. 2)
12.9450(3)
15.8550(4)
19.7860(5)
101.010(2)
91.365(1)
90.110(1)
3984.97(17)
2
P1 (No. 2)
11.4620(1)
15.0460(2)
16.2070(2)
100.190(1)
93.125(1)
97.346(1)
2719.82(5)
2
˚
a/A
10.4940(1)
39.4160(5)
19.0500(2)
90
29.3244(2)
29.3244(2)
17.9383(2)
90
˚
b/A
˚
c/A
R/deg
β/deg
γ/deg
100.025(1)
90
90
90
3
˚
U/A
Z
7759.37(15)
4
1.525
15425.5(2)
8
1.511
Dc/g cm-3
μ/mm-1
F(000)
1.499
0.363
1812
1.429
0.729
1216
0.547
3584
0.491
7120
crystal size/mm
θ min., max for data collection
index ranges
0.20 ꢀ 0.20 ꢀ 0.12
3.55, 27.47
-16 e h e 16;
-18 e k e 19;
-22 e l e 25
22391
0.25 ꢀ 0.20 ꢀ 0.20
3.51, 27.52
-14 e h e 14;
-19 e k e 19;
-20 e l e 21
55440
0.15 ꢀ 0.15 ꢀ 0.12
3.61, 27.53
-13 e h e 13;
-51 e k e 51;
-24 e l e 24
98604
0.35 ꢀ 0.35 ꢀ 0.24
2.75 to 27.48
-38 e h e 38;
-38 e k e 38;
-23 e l e 23
253414
reflections collected
independent reflections, Rint
reflections observed (>2σ)
data completeness
15058, 0.0389
11363
0.824
12442, 0.0580
9843
0.995
17766, 0.0633
12706
0.994
17670, 0.0412
12713
0.999
absorption correction
max., min transmission
data/restraints/parameters
goodness-of-fit n F2
multiscan
0.927, 0.895
15058/151/1115
1.047
multiscan
0.870, 0.821
12442/1/662
1.053
multiscan
0.901, 0.829
17766/121/1099
1.027
multiscan
1.000 and 0.944
17670/139/898
1.094
three THF molecules in addition to one molecule of the com-
plex. The structure of 2a also fell prey to lattice solvent. Within
the asymmetric unit, two full molecules of dichloromethane
were in evidence, along with an additional region of electron
density that was modeled as 0.7 of a CH2Cl2 molecule. The latter
was split over two sites in a 50:20 ratio and, to assist conver-
gence, C-Cl and Cl Cl distances were restrained in the
disordered region.
Compound 3a proved challenging from a solid-state char-
acterization perspective, the sample in this case, a thin plate,
3 3 3

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7249
Scheme 1
being of less than ideal quality. The asymmetric unit was seen to
comprise one cation, one anion, and a hopeless region of dis-
ordered solvent. The hydrogen atoms in the ligated water were
located with reasonably convincing credibility, and refined at
symmetry), and one-quarter of a cation. The first three of these
components refined easily, but the cation quarter represented a
catastrophe in terms of modeling. The forced -4 symmetry
position close to the ruthenium at the center of this moiety
forced geometrical restraints which do not coincide with the
point group symmetry of a full cation. Hence, disorder was rife,
and could not be modeled sensibly. It became evident therefore,
that to effect a good convergence, this region would need to be
treated with the PLATON SQUEEZE function. However, before
taking this pathway, an optimal quality data set is necessary, and
hence, a second collection ensued. Refinement of the structure
using these new data revealed a very disordered molecule of
THF to also be present within the asymmetric unit. Rigorous
attempts were made to model the two disordered regions, but to
no avail. Lower symmetry space group possibilities plus twin-
ning were also considered, but these alternatives caused conver-
gence deterioration. Moreover, the electron density map region
pertaining to the second cation could not be resolved any better,
even at the very lowest of the symmetries interrogated. Thus,
SQUEEZE was employed, and because of the data quality, there
is good agreement between the calculated electron counts in the
voids and the chemical model evident before using this algo-
rithm. The unit cell contents presented herein take account of
the “squeezed” solvent and cation quarter. Some disorder of the
CF3 groups was also modeled successfully in this structure. In
particular, the fluorines attached to C39, C45, C54, and C55
were seen to be disordered in the following ratios, respectively:
˚
˚
0.89 A from O2, 1.6 A from each other, and equidistant from
Ru1. Disorder reigned in relation to the fluorines in the anion. In
particular, the halogens in the CF3 groups containing F10, F19,
and F22 exhibited 65:35 disorder, while the fluorines in the
group containing F16 were shown to have 50:50 disorder. C-F
and F-F distances in disordered regions were refined subject to
similarity restraints. Fractional fluorines with occupancy of less
than 50% were treated isotropically. The solvent region in this
structure is best described as “messy”. Ultimately this region
was modeled as partial carbon atoms (i.e., a fractional pentane
of recrystallization) with the hydrogens not included in this
region.
In 5a, the asymmetric unit was seen to be constituted by one
cation, one anion, and a solvent fragment that approximates to
half of a molecule of dichloromethane. Disorder was prevalent
in all three species. Specifically, the phenyl rings containing
carbons 16-21 and 22-26 were disordered over 2 sites in a 1:1
ratio. These partial rings were treated as rigid hexagons in the
refinement. Unsurprisingly, some of the CF3 groups in the anion
also exhibited disorder. Those fluorine atoms attached to C81
and C88 were found to be disordered in site-occupancy ratios of
55:45 and 50:50 respectively. C-F and F F distances were
3 3 3
restrained in these disordered functionalities during the final
least-squares cycles. Partial atoms with occupancies of 50% or
greater were refined anisotropically, subject to restraints. The
solvent was diffuse, and difficulties in modeling same were
overcome by employing the PLATON “SQUEEZE” function.17
On this basis, half of a CH2Cl2 molecule has been included in the
asymmetric unit for this structure.
75:25; 60:40; 65:35, and 55:45. C-F and F F distances in
3 3 3
disordered functionalities were refined subject to restraints and
only partial fluorines with greater than 50% occupancy were
refined anisotropically.
Crystallographic data for compounds 1a (766186), 1b (766187),
1c (766188), 2a (780097), 3a (766189), 5a (766190), 5b (766191),
1d (766192), 8 (766193), and 10 (766194) have been deposited
with the Cambridge Crystallographic Data Center as supple-
mentary publications. Copies of the data can be obtained free of
charge on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, U.K. [fax(þ44) 1223 336033, e-mail: deposit@ccdc.
cam.ac.uk].
The sample for 5b crystallized as flat plates, and this is
evidenced, in part, by the R(int) for the data which were
truncated at a θ value of 25°. There was no solvent present in
8, but the central ruthenium in the cation exhibited 75:25
disorder over two sites, both of which were treated anisotropi-
cally. A credible hydride position was evident in the difference
Fourier electron density map, and this was refined, as described
˚
above, at 1.6 A from the 75% occupancy metal, rather than split
Results and Discussion
over 2 sites. Some of the fluorines in the anion also exhibited
disorder. In particular, F1-3/F1A-3A, F7-9/F7A-9A, F10-12/
F10A-12A, and F13-15/F13A-15A refined with disorder ratios
Synthesis and Characterization of Ru(P-O-P)(PPh3)-
HCl (1a-c). The chelating phosphine precursors Ru(P-
O-P)(PPh3)HCl (xantphos, 1a; DPephos, 1b; (Ph2PCH2-
CH2)2O, 1c) were prepared by refluxing Ru(PPh3)3HCl
with 1-3 equiv of the appropriate phosphine ligands in
THF, and isolated as mildly air-sensitive orange solids in
good to excellent yields (60-90%). The 31P{1H} NMR
spectra of 1a and 1c displayed a triplet signal for the
triphenylphosphine ligand at δ 75.2 and δ 71.0 respec-
tively, along with a lower frequency doublet resonance at
δ 46.7 (1a) and δ 42.3 (1c) arising from the coordinated
of 65:35, 55:45, 65:35, and 80:20, respectively. C-F and F
F
3 3 3
distances in disordered CF3 groups were refined subject to
distance similarity restraints.
The structure of 10 was somewhat tricky to finalize. An initial
data collection revealed that the asymmetric unit contained one
full cation, one full anion, one-quarter of an anion (with the
central boron, B2, located on a special position bearing -4
(17) Spek, A. L. A Multipurpose Crystallographic Tool; Utrecht University:
Utrecht, The Netherlands, 2001.

7250 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
P-O-P ligands. The splitting patterns and coupling
constants (2JPP ca. 33 Hz) are consistent with 1a-c
adopting mer P-O-P geometries as shown in Scheme
1. In the case of 1b, the phosphorus resonances of the
DPEphos ligand appeared as a broad singlet at room
temperature, but resolved upon cooling to 230 K into an
2
ABX spin system with a trans JPP coupling of 285 Hz.
The non-equivalence of the two P-atoms within the
chelate arises from a conformation of the complexed
ligand in which the four P-phenyl groups adopt pseudo-
1
axial and pseudo-equatorial positions. The H NMR
spectra of the three complexes all exhibited a single
hydride resonance (1a: δ -16.22; 1b: δ -16.34; 1c: δ
-17.54) with a doublet of triplets multiplicity. The
magnitude of the JHP couplings indicate a cis disposition
of hydride with respect to both the chelating phosphines
and the PPh3 ligands.
The molecular structures of 1a-c were determined by
X-ray crystallography and are displayed in Figure 1, with
pertinent bond lengths and angles listed in Table 2. In all
of the structures, the chelating phosphines are coordi-
nated through all three POP atoms in a mer-configuration
with trans P-Ru-P angles between 156 and 158°. Co-
ordination of the oxygen atom is presumably desirable in
allowing the complexes to achieve 18-electron counts. It is
notable that in 1a and 1b there is substantial evidence for
intramolecular π stacking involving one phenyl ring from
the chelating phosphine and another from the triphenyl-
phosphine ligand. In particular, the shortest distances
between the mean planes of the rings based on C29 and
˚
C41 in 1a and C25 and C37 in 1b are 3.28 and 3.24 A,
˚
respectively. The Ru-Pchelate distances (2.29-2.34 A) are
considerably longer than the Ru-PPh3 distances (all ca.
˚
2.22 A), while the Ru-O distances lie within the range
˚
2.25-2.28 A.
Chloride Abstraction from 1a-c. Treatment of dichlo-
F
romethane solutions of 1a-c with 1.1 equiv of NaBAr4
(BAr4F = B(3,5-C6H3(CF3)2)4) resulted in abstraction of
the chloride ligands and the appearance of hydride signals
for the products 3a-c at lower frequencies (δ -19.67, δ
-18.67, and δ -21.05) than found in the neutral starting
materials. This is consistent with 3a-c having hydride
ligands either trans to a vacant coordination site (i.e., as
in the 16e species [Ru(P-O-P)(PPh3)H]þ) or trans to a
weakly bound solvent molecule (i.e., as the 18e species
[Ru(P-O-P)(PPh3)(solvent)H]þ).18 Although an X-ray
structure of a crystal of 3a isolated (serendipitously!) from
a reaction of 1a with NaBAr4F revealed a loosely bound
19
˚
water molecule (Ru-OH2 = 2.32(5) A) in the sixth
coordination site on the metal (Figure 3), we sought
conclusive evidence for solvent coordination in the bulk
material in solution.
(18) (a) Esteruelas, M. A.; Werner, H. J. Organomet. Chem. 1986, 303,
221–231. (b) Salem, H.; Shimon, L. J. W.; Diskin-Posner, Y.; Leitus, G.;
Ben-David, Y.; Milstein, D. Organometallics 2009, 28, 4791–4806.
(19) For comparisons, see for example: (a) Boniface, S. M.; Clark, G. R.;
Collins, T. J.; Roper, W. R. J. Organomet. Chem. 1981, 206, 109–117.
(b) Harding, P. A.; Robinson, S. D.; Henrick, K. J. Chem. Soc., Dalton Trans.
1988, 415–420. (c) Goicoechea, J. M.; Mahon, M. F.; Whittlesey, M. K.; Kumar,
P. G. A.; Pregosin, P. S. Dalton Trans. 2005, 588–597. (d) Zhang, J.; Gandelman,
M.; Shimon, L. J. W.; Milstein, D. Dalton Trans. 2007, 107–113. (e) Szymczak,
N. K.; Braden, D. A.; Crossland, J. L.; Turov, Y.; Zakharov, L. N.; Tyler, D. R.
Inorg. Chem. 2009, 48, 2976–2984.
Figure 1. Molecular structures of Ru(xantphos)(PPh3)HCl (1a), Ru-
(DPEphos)(PPh3)HCl (1b), and Ru((Ph2PCH2CH2)2O)(PPh3)HCl (1c).
Thermal ellipsoids are shown at 30% level. Solvent moieties and all
hydrogen atoms, except Ru-H, are omitted for clarity.
A series of NMR experiments proved beyond doubt
that 3a-c are the aqua complexes [Ru(P-O-P)(PPh3)-
(H2O)H]þ. Thus, a proton NMR spectrum of 3a recorded

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7251
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) for Ru(xantphos)-
(PPh3)HCl (1a), Ru(DPEphos)(PPh3)HCl (1b), and Ru((Ph2PCH2CH2)2O)-
(PPh3)HCl (1c)
1a
1b
1c
Ru(1)-P(1)
2.3037(8)
2.3060(8)
2.2277(8)
2.2509(19)
2.5200(8)
156.39(3)
98.66(3)
100.18(3)
176.46(6)
100.16(3)
2.3319(7)
2.2918(7)
2.2271(7)
2.2480(17)
2.5120(7)
156.52(3)
101.76(2)
98.52(3)
2.3085(9)
2.3364(8)
2.2292(8)
2.278(2)
2.5192(9)
158.31(3)
98.91(3)
99.48(3)
171.08(6)
101.63(3)
Ru(1)-P(2)
Ru(1)-P(3)
Ru(1)-O(1)
Ru(1)-Cl(1)
P(1)-Ru(1)-P(2)
P(1)-Ru(1)-P(3)
P(2)-Ru(1)-P(3)
O(1)-Ru(1)-P(3)
Cl(1)-Ru(1)-P(3)
177.05(6)
96.82(2)
Figure 3. Structure of the cation in [Ru(xantphos)(PPh3)(H2O)H]-
BAr4 (3a). Thermal ellipsoids are shown at 30% level. All hydrogen
F
atoms, exceptRu-H and Ru-OH2, are omitted for clarity. Selectedbond
˚
lengths (A) andangles(deg): Ru(1)-P(1) 2.306(13), Ru(1)-P(2) 2.298(13),
Ru(1)-P(3) 2.228(13), Ru(1)-O(1) 2.25(3), Ru(1)-O(2) 2.32(4), P(1)-
Ru(1)-P(2) 160.1(5), P(1)-Ru(1)-P(3) 99.4(5), P(2)-Ru(1)-P(3)
99.5(5), O(1)-Ru(1)-P(3) 173.1(10).
2a in CD2Cl2 produced a new hydride signal at even
higher frequency, δ -13.42, assigned to 4a; a comparable
chemical shift (δ -13.39) was observed when 5 equiv of
MeCN were added to a sample of 1a/ NaBAr4F. More
definitive evidence for acetonitrile coordination came
from the observed proton singlet at δ 1.36, together with
carbon resonances at δ 2.9 and 121.8, and finally, a band
corresponding to νCN at 2241 cm-1 in the IR spectrum.
Reaction of 3a-c with O2. Exposure of CH2Cl2 solu-
tions of 3a-c to air at room temperature led to the rapid
(and irreversible) formation of the cationic dioxygen
Figure 2. Molecular structure of Ru(xantphos)(PPh3)H(OTf) (2a).
Thermal ellipsoids are shown at 30% level. All hydrogen atoms, except
Ru-H, areomitted for clarity. Selectedbondlengths(A) andangles(deg):
Ru(1)-P(1) 2.3062(6), Ru(1)-P(2) 2.3118(5), Ru(1)-P(3) 2.2424(6),
Ru(1)-O(1) 2.2563(15), Ru(1)-O(2) 2.3139(17), P(1)-Ru(1)-P(2)
156.72(2), P(1)-Ru(1)-P(3) 96.72(2), P(2)-Ru(1)-P(3) 98.92(2), O(1)-
Ru(1)-P(3) 175.34(4), O(1)-Ru(1)-O(2) 81.50(6).
˚
F
hydride complexes [Ru(P-O-P)(PPh3)(η2-O2)H]BAr4
(5a-c), which were isolated and structurally character-
ized in the cases of xantphos (5a) and DPEphos (5b).
Yellow solutions of complex 5c rapidly reveal a green tint
suggesting oxidation to Ru(III). Similar green solutions
were also observed with the xantphos and DPEphos
derivatives if they were formed by reaction with O2 rather
than air.
immediately after reaction of 1awith NaBAr4F in degassed,
but undried, dichloromethane showed a single Ru-H
resonance with the same chemical shift value (δ -19.67)
reported above, although the signal was broad and devoid
of any resolvable couplings to phosphorus, suggestive of
exchange.20 Moreover, when 2 equiv of water were added
to a CD2Cl2 solution of the triflate complex Ru(xant-
phos)(PPh3)H(OTf) (2a, Figure 2), the initial Ru-H
signal of 2a at δ -22.2721 shifted to higher frequency (δ
-21.81) and broadened. With a total of 10 equiv of water
present, the hydride resonance appeared at even higher
frequency, δ -19.98. As expected, a more coordinating
solvent such as acetonitrile was also able to displace
the triflate ligand from 2a to give [Ru(xantphos)(PPh3)-
(MeCN)H]OTf (4a). Thus, addition of MeCN (5 equiv) to
The 1H NMR spectra of 5a-c all display hydride signals
at a relatively high frequency between δ -1.5 and δ -3 as a
2
doublet of triplets with JHP values in the range 26-32
Hz, consistent with structures shown in Scheme 2 in which
O2 is coordinated trans to hydride. All three chemical
shifts are intermediate between the value of δ -5.8 for
[Ru(iPr2PCH2CH2PiPr2)2(η2-O2)H]þ and the positive va-
lue of δ 4.8 reported recently for the N-heterocyclic
carbene species [Ru(IiPr2Me2)4(η2-O2)H]þ (IiPr2Me2 =
1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene).22-24 In
the 31P{1H} NMR spectra, the coordination of oxygen
leads to similar chemical shifts for both the chelating
ꢀ
(20) We were unable to identify resonances arising from the coordinated
water ligand.
(21) Upon warming to 315 K, we observed sharpening of the resonance to
(22) Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. J. Am. Chem. Soc.
1993, 115, 9794–9795.
ꢀ
(23) Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. Inorg. Chem. 1994,
the expected doublet of triplets multiplicity.
33, 3515–3520.

7252 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
Figure 4. Molecular structures of the cations in [Ru(xantphos)(PPh3)(η2-O2)H]BAr4 (5a) and [Ru(DPEphos)(PPh3)(η2-O2)H]BAr4 (5b). Thermal
F
F
˚
ellipsoids are shown 30% level. All hydrogen atoms, except Ru-H, are omitted for clarity. Selected bond lengths (A) and angles (deg) for 5a: Ru(1)-P(1)
2.339(2), Ru(1)-P(2) 2.3493(19), Ru(1)-P(3) 2.2883(19), O(2)-O(3) 1.453(7), Ru(1)-O(1) 2.257(4), Ru(1)-O(2) 2.006(5), Ru(1)-O(3) 2.026(5),
P(1)-Ru(1)-P(2) 125.58(7), P(1)-Ru(1)-P(3) 102.49(7), P(2)-Ru(1)-P(3) 101.78(7), O(1)-Ru(1)-P(3) 176.79(13). For 5b: Ru(1)-P(1) 2.3477(13),
Ru(1)-P(2) 2.3294(13), Ru(1)-P(3) 2.2867(13), O(2)-O(3) 1.436(5), Ru(1)-O(1) 2.298(3), Ru(1)-O(2) 2.024(3), Ru(1)-O(3) 2.005(3), P(1)-Ru(1)-
P(2) 119.48(4), P(1)-Ru(1)-P(3) 103.89(5), P(2)-Ru(1)-P(3) 102.20(5), O(1)-Ru(1)-P(3) 179.32(9).
Scheme 2
ligands and the PPh3 groups (5a: δ 48.2, 44.4; 5b: δ 41.4,
36.2; 5c δ 48.2, 45.8). IR spectroscopy was uninformative
as the ν(O-O) stretches for both the 16O2 and 18O2 iso-
topomers of 5a and 5b were obscured by other absorption
bands.
are significant distortions to the xantphos and DPEphos
ligands in 5a-b compared with 1a-b. Specifically, the
P-Ru-P angle narrows dramatically from about 156° in
the latter structures, to 125.58(7)° in 5a and 119.48(4)° in
5b. This change is concomitant with increased “hinging”
of the xanthene about the O1-C6 axis in 5a (angle
between the aromatic ring mean planes is 149.3°) and in
5b by the reduction in the P-O-P angle to 89.1° com-
pared to 101.7° in 1b.
The molecular structures of 5a-b are shown in Figure
˚
4. The O-O distances of 1.453(7) (5a) and 1.436(5) A (5b)
are significantly longer than those reported in either [Ru-
i
(dippe)2(η2-O2)H]þ (1.360(10) A; dippe = Pr2PCH2-
˚
CH2PiPr2)22,23 or [Ru(IiPr2Me2)4(η2-O2)H]þ (1.354(5)
Reaction of 3a-c with H2 and D2. Treatment of 1a-c
with NaBAr4F in dichloromethane followed by addition
of 1 atm H2 afforded the thermally unstable dihydrogen
A),24 but in the range for coordinated peroxide.25 There
˚
€
ꢀ
hydride complexes [Ru(P-O-P)(PPh3)(η2-H2)H]BAr4
(24) Haller, L. J. L.; Mas-Marza, E.; Moreno, A.; Lowe, J. P.; Macgregor,
S. A.; Mahon, M. F.; Pregosin, P. S.; Whittlesey, M. K. J. Am. Chem. Soc.
2009, 131, 9618–9619.
F
(6a-c), which were characterized by comparison of the
Ru-H and Ru(η2-H2) chemical shifts to analogous ruthe-
nium complexes in the literature.26 The low frequency region
of the 1H NMR spectrum of [Ru(xantphos)(PPh3)(η2-H2)-
(25) (a) Vaska, L. Acc. Chem. Res. 1976, 9, 175–183. (b) Mezzetti, A.;
Zangrando, E.; Del Zotto, A.; Rigo, P. J. Chem. Soc., Chem. Commun. 1994,
1597–1598. (c) Yu, X.-Y.; Patrick, B. O.; James, B. R. Organometallics 2006, 25,
4870–4877; For a critical analysis of M-O2 bonding, see: . Cramer, C. J.; Tolman,
W. B.; Theopold, K. H.; Rheingold, A. L. Proc. Natl. Acad. Sci. U.S.A. 2003,
100, 3635–3640.
F
H]BAr4 (6a) recorded in CD2Cl2 at 180 K displayed
a broad singlet at δ -0.95 arising from the η2-H2 ligand

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7253
Table 3. NMR Data for [Ru(P-O-P)(PPh3)(η2-H2)H]BAr4F (6a-c)
c
compound
δ Ru(η2-H2)
-0.95
δ/JHP Ru-H
δ 31
P
T1
6aa
-8.79 (22.4, 19.1 Hz)
67.6, 51.9
η2-H2: 9.0 ms (240 K)d
H: 381 ms (239 K)e
η2-H2: 9.6 ms (236 K)d
H: 324 ms (239 K)e
η2-H2: 7.7 ms (224 K)d
H: 273 ms (228 K)e
6bb
6cb
-0.25
-1.91
-7.95 (22.8, 19.4 Hz)
-9.16 (23.6, 16.2 Hz)
69.2, 47.1, 46.2
66.9, 56.2
a Recorded at 180 K. b Recorded at 195 K. c Measured at 400 MHz. d T1min values. e T1(obs) values at the closest recorded temperatures to the T1min values
of the dihydrogen ligands.
and a doublet of triplets at δ -8.79 (2JHP = 22 and 19 Hz)
for the terminal Ru-H. The similarity of JHP to the values
determined for 5a-c suggests that the H2 ligand lies trans
to the hydride (Scheme 2). All three H-Ru(η2-H2) com-
plexes were only stable under an atmosphere of hydro-
gen, and moreover, were present in equilibrium with the
aqua precursors 3a-c.27 In the case of the xantphos
species, the ratio of 6a/3a was 3.8:1 at 180 K and 2.1:1
at 239 K.
Further evidence for assignment of 6a-c as dihydrogen
hydride complexes was provided by measurement of their
spin-lattice relaxation times. A T1 min value of 9 ms was
determined for the η2-H2 ligand in the case of 6a (240 K,
400 MHz), corresponding to an H-H separation of 0.98
˚
or 0.78 A for either a slow or a fast-spinning dihydrogen
Figure 5. Hydride region of the 1H {31P} NMR spectrum (CD2Cl2, 400
ligand.28 As expected, the T1 value for the terminal Ru-H
MHz, 180 K) (a) immediately after addition of 1 atm D2 to [Ru(DPEphos)-
(PPh3)(H2O)H]BAr4F (3b), (b) after a further 24 h at room temperature,
(c) after then being freeze-pump-thaw degassed and 1 atm D2 reintro-
duced, and (d) a further 24 h later.
was much longer. Table 3 summarizes the pertinent NMR
data for the three dihydrogen hydride complexes.
Exposure of 3a-c to 1 atm D2 produced relatively
complicated low temperature 1H NMR spectra, with
isotopic scrambling leading to the formation of a mixture
of isotopomers. As shown in Figure 5 for the DPEphos
complex 3b, four resonances were seen in the hydride re-
gion of the 1H{31P} spectrum recorded at 180 K immedi-
ately after addition of D2. After one day, the relative
intensities of the four peaks had changed, with that at
highest frequency decreasing and that at lowest frequency
increasing. After degassing and addition of a fresh atmo-
sphere of D2, the intensities of the three lowest frequency
signals all reduced, only to increase after a further 24 h.
This variation of peak intensity as a function of time leads
us to assign the highest frequency peak to [Ru(DPEphos)-
(PPh3)(η2-D2)H]BAr4F, while that at the lowest fre-
quency is assigned to the dihydrogen hydride species
6b.29,30 The formation of 6b implies some form of H-D
exchange process, most likely involving ortho-metalation
Scheme 3
of the aryl group(s) on the phosphine ligand(s).31 In
support of this, deuterium incorporation into the aro-
matic region was apparent from the 2H NMR spectrum.
We propose that the two remaining signals arise from
two isomers of [Ru(DPEphos)(PPh3)(η2-HD)H]BAr4F in
which the η2-HD ligand sits on either side of the non-
planar DPEphos ligand, as shown in Scheme 3.32
The presence of the different HD isotopomers makes
the dihydrogen region around δ -0.25 broad and un-
resolved, even with 31P-decoupling. The experimental
spectrum could be fitted with a simulation involving four
η2-HD isotopomers (arising as above from the η2-HD
ligand being either side of the DPEphos ligand and trans
to either Ru-H or Ru-D) in which the 1:1:1 triplets
partially overlap.33 The simulated JHD values range from
29.7 to 31.7 Hz, corresponding to an H-H separation of
(26) (a) Bautista, M. T.; Cappellani, E. P.; Drouin, S. D.; Morris, R. H.;
Schweitzer, C. T.; Sella, A.; Zubkowski, J. J. Am. Chem. Soc. 1991, 113,
4876–4887. (b) Jia, G.; Drouin, S. D.; Jessop, P. G.; Lough, A. J.; Morris, R. H.
Organometallics 1993, 12, 906–916. (c) Field, L. D.; Hambley, T. W.; Yau,
B. C. K. Inorg. Chem. 1994, 33, 2009–2017. (d) Ogasawara, M.; Saburi, M.
J. Organomet. Chem. 1994, 482, 7–14. (e) Schlaf, M.; Lough, A. J.; Morris, R. H.
Organometallics 1997, 16, 1253–1259.
(27) For a discussion on the coordination of H2O versus H2, see: Kubas,
G. J.; Burns, C. J.; Khalsa, G. R. K.; Van Der Sluys, L. S.; Kiss, G.; Hoff,
C. D. Organometallics 1992, 11, 3390–3404.
˚
0.89-0.92 A. This is relatively close to the value for a
slow-spinning dihydrogen ligand calculated on the basis
of the T1 min determination, although it is worth noting that
in a recent summary of group 8 dihydrogen complexes,
(28) (a) Morris, R. H. Coord. Chem. Rev. 2008, 252, 2381–2394. (b) Morris,
R. H. Coord. Chem. Rev. 2009, 253, 1219–1219.
(29) This resonance overlays perfectly that of 6b.
(30) For a discussion of chemical shifts in partially deuterated hydride
species, see: Oldham, W. J., Jr.; Hinkle, A. S.; Heinekey, D. M. J. Am. Chem.
Soc. 1997, 119, 11028–11036.
(31) We assume that this involves metalation at the PPh3 groups rather
than the P-O-P ligands, but have not established this conclusively.
(32) Alternatively, there may be specific orientations of the η2-HD ligand
that cannot be interconverted. For example, the η2-HD ligand could lie along
the O-Ru-P vector with either the H or D over the Ru-O bond.
(33) See Supporting Information.

7254 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
Table 4. NMR Data for [Ru(P-O-P)(PPh3)(N2)H]BAr4F (7a-c)
compound
δ/JHP Ru-Ha
δ 31Pa
δ 15
-88.7, -57.6b
N
7a
7b
7c
-11.72 (26.0, 16.5 Hz) 68.2, 47.8
-11.04 (26.7, 20.0 Hz) 65.4, 43.1, 41.7 -82.6, -51.8b
-12.06 (25.3, 16.6 Hz)c -67.2, 51.1c -86.2, -59.1c
a Recorded at 180 K. b Recorded at 193 K. c Recorded at 195 K.
All three dinitrogen complexes were present in equilib-
rium with their aqua precursors. In the case of the
xantphos derivative, for example, the ratio of 7a/3a at
190 K was 6.7:1, but only 1.2:1 at 210 K. In the proton
NMR spectrum at 266 K, only a very broad signal in the
baseline corresponding to the hydride signal of 3a was
present.
In the reaction of 3a with air to give 5a, there was no
trace of the dinitrogen complex 7a found by NMR at low
temperature indicating preferential binding of O2 over
N2. Such a finding is consistent with previous experimen-
tal observations,35 and also more recent computational
studies on the coordination of the two molecules to
[Ru(NHC)4H]þ and [Ru(dippe)2H]þ.36
η6-PPh3 Coordination Upon Halide Abstraction from
Ru(dppf)(PPh3)HCl. In an attempt to establish the im-
portance of the tridentate P-O-P coordination mode in
allowing [Ru(P-O-P)(PPh3)(H2O)H]þ to coordinate
small molecules, we turned to the rigidly bidentate phos-
phine ligand dppf. The ruthenium complex Ru(dppf)-
(PPh3)HCl (1d) was formed as an orange, moderately
air-stable solid in 48% yield by simply refluxing Ru(PPh3)3-
HCl in the presence of 1 equiv of the ligand (Scheme 4).37
As reported for the corresponding tricyclohexylphosphine
analogue, Ru(dppf)(PCy3)HCl,38 1d is fluxional in solu-
tion. The ambient temperature 31P{1H} NMR spectrum
displayed a broad singlet at δ 65 and a triplet at δ 41
assigned to the dppf and PPh3 ligands, respectively. At
195 K, an ABX spin system was observed, with a large
trans-JPP coupling of 294 Hz associated with the PPh3
and one of the dppf phosphorus signals. The data are
consistent with a distorted trigonal bipyramidal arrange-
ment found in Ru(dppf)(PCy3)HCl. This was proven by
an X-ray crystal structure determination, which is illu-
strated in Figure 7. The PPh3 ligand and one arm of the
dppf are indeed trans, occupying the apical positions of the
tbp structure (P(1)-Ru-P(3), 159.45(3)°).39 These apical
Ru-P distances (Ru-P(1) 2.3587(7), Ru-P(3) 2.3086(7)
Figure 6. 1H-15N HMQC spectrum (700 MHz, CD2Cl2, 193 K) of
[Ru(xantphos)(PPh3)(N2)H]BAr4F (7a). Shown are the cross-peaks aris-
ing from the 2- and 3-bond correlations of the hydride ligand to NR and
Nβ, respectively.
Morris reported that most of the trans H-Ru(η2-H2)
complexes in the literature contain an η2-H2 ligand in the
fast-spinning regime.28
Reaction of 3a-c with N2. Treatment of 1a-c with
NaBAr4F followed by addition of 1 atm N2 generated the
trans-dinitrogen hydride complexes [Ru(P-O-P)(PPh3)-
F
(N2)H]BAr4 (7a-c). As in the cases of 6a-c discussed
above, these species were only stable at low temperature
under 1 atm N2, and could therefore only be characterized
spectroscopically by a combination of 1- and 2-D 1H and
15N NMR methods. The xantphos derivative 7a is used to
illustrate representative NMR data. It shows a hydride
signal at δ -11.72 (180 K) that exhibits a relatively large
trans JHN doublet splitting of 18 Hz in the 1H{31P} NMR
spectrum of a 15N labeled sample. The 193 K 15N{1H}
NMR spectrum of 7a displayed two resonances at δ -88.7
and δ -57.6 which were assigned to the R- and β-N atoms,
respectively, by comparison to the literature. Moreover,
these chemical shifts point to 7a-c being clear cases of
mononuclear ruthenium complexes with end-on bound
N2 ligands.34 Both signals displayed cross-peaks to the
hydride resonance at δ -11.72 in the corresponding
1H-15N HMQC spectrum (Figure 6). A 15N NMR satu-
ration transfer experiment performed at 193 K on 7a
and 7b revealed exchange between the complexed N2 and
free dinitrogen in solution. NMR data for the three
dinitrogen hydride complexes 7a-c are summarized in
Table 4.
˚
A) are significantly longer than the equatorial Ru-P
˚
bond length (Ru-P(2) 2.1850(7) A).
Treatment of 1d with NaBAr4F failed to give an analo-
gue of 3a-c, but instead afforded [Ru(dppf){(η6-C6H5)-
PPh2}H]BAr4 (8), in which the PPh3 ligand is now
coordinated through one of the aryl rings instead of the
F
(35) Jia, G.; Ng, W. S.; Chu, H. S.; Wong, W.-T.; Yu, N.-T.; Williams,
I. D. Organometallics 1999, 18, 3597–3602.
€
ꢀ
(36) Burling, S.; Haller, L. J. L.; Mas-Marza, E.; Moreno, A.; Macgregor,
S. A.; Mahon, M. F.; Pregosin, P. S.; Whittlesey, M. K. Chem.;Eur. J. 2009,
15, 10912–10923.
(37) An alternative route to this material has been described in a patent.
Rautenstrauch, V.; Challand, R.; Churlaud, R.; Morris, R. H.; Abdur-
Rashid, K.; Brazi, E.; Mimoun, H. World Patent WO 2002022526 A2
20020321, 2002.
(38) Jung, S.; Brandt, C. D.; Werner, H. Dalton Trans. 2004, 375–383.
(39) In [Ru(dppf)(PPh3)(CO)Cl]BF4, the bite angle of the dppf ligand
expands to adopt a trans-spanning geometry. Kawano, H.; Nishimura, Y.;
Onishi, M. Dalton Trans. 2003, 1808–1812.
(34) Donovan-Mtunzi, S.; Richards, R. L.; Mason, J. J. Chem. Soc.,
Dalton Trans. 1984, 469–474.

Article
Inorganic Chemistry, Vol. 49, No. 16, 2010 7255
Figure 7. Molecular structure of Ru(dppf)(PPh3)HCl (1d). Thermal
ellipsoids are shown at 30% level. Solvent and all hydrogen atoms, except
˚
Ru-H, areomitted for clarity. Selectedbondlengths(A) andangles(deg):
Ru(1)-P(1) 2.3587(7), Ru(1)-P(2) 2.1850(7), Ru(1)-P(3) 2.3086(7),
Ru(1)-Cl(1) 2.4400(7), P(1)-Ru(1)-P(2) 98.84(3), P(1)-Ru(1)-P(3)
159.45(3), P(2)-Ru(1)-P(3) 99.96(3), Cl(1)-Ru(1)-P(2) 126.18(3).
Figure 8. Structure of the cation in [Ru(dppf){(η6-C6H5)PPh2}H]BAr4
F
(8). Thermal ellipsoids are shown at 30% level. All hydrogen atoms,
˚
except Ru-H, are omitted for clarity. Selected bond lengths (A) and
Scheme 4
angles (deg): Ru(1)-P(2) 2.3001(8), Ru(1)-P(3) 2.3131(8), Ru(1)-C(1)
2.392(3), Ru(1)-C(2) 2.295(3), Ru(1)-C(3) 2.223(3), Ru(1)-C(4)
2.183(3), Ru(1)-C(5) 2.195(3), Ru(1)-C(6) 2.282(3), P(1)-C(1)
1.838(3), P(1)-C(7) 1.827(4), P(1)-C(13) 1.823(4), P(2)-Ru(1)-P(3)
96.03(3).
were observed in the phosphorus spectrum at δ 50.2
and -8.1, with the lower frequency signal assigned to
the η6-coordinated PPh3 ligand by comparison to the
literature.43 In the 13C{1H} NMR spectrum, four low
frequency aryl carbon resonances were observed between
94 and 110 ppm arising from the η6-coordinated ring. The
proton NMR spectrum at ambient temperature displayed
a single resonance at low frequency at δ -9.32 with a 39 Hz
triplet splitting due to the dppf ligand, and somewhat
surprisingly, a 7 Hz coupling to the uncoordinated phos-
phorus center.
Solution Reactivity of 8. The formation of [Ru(dppf)-
{(η6-C6H5)PPh2}H]BAr4F (8) following chloride abstrac-
tion from 1d presumably reflects the need of the initially
formed [Ru(dppf)(PPh3)H]þ cation to gain electron den-
sity. When 8 was treated with either H2 or N2, no reaction
was observed. Similarly, addition of CO gave very little
reaction at room temperature, but upon heating at 343 K
for 15 h, the PPh3 ligand reverted to being P-bound and
two molecules of CO were coordinated to give [Ru(dppf)-
(PPh3)(CO)2H]BArF4 (9). The appearance of a single νCO
band in the solution IR spectrum of the compound is
suggestive of a trans dicarbonyl geometry, as shown in
Scheme 5.44 This was confirmed by reacting 8 with 13CO,
phosphorus atom (Scheme 4).40-42 The X-ray crystal
structure of 8 (Figure 8) reveals a distorted piano-stool
arrangement of the η6-arene, dppf, and hydride ligands
around the ruthenium center. The coordinated arene is
asymmetrically bound to the ruthenium, as evidenced by
˚
the longer (2.392(3) A) Ru-C distance for the phos-
phorus bound carbon atom, compared with the average
˚
of the remaining Ru-C distances (2.23 A).
Multinuclear NMR spectroscopy indicated that the struc-
ture of 8 was retained in solution. Two singlet resonances
(40) For an early example of η6-coordinated PPh3 ligand see: McConway,
J. C.; Skapski, A. C.; Phillips, L.; Young, R. J.; Wilkinson, G. J. Chem. Soc.,
Chem. Commun. 1974, 327–328.
(41) For other η6-coordinated group 15 element ligands, see: (a) Becker,
€
E.; Slugovc, C.; Ruba, E.; Standfest-Hauser, C.; Mereiter, K.; Schmid, R.;
Kirchner, K. J. Organomet. Chem. 2002, 649, 55–63. (b) Hermatschweiler, R.;
Pregosin, P. S.; Albinati, A.; Rizzato, S. Inorg. Chim. Acta 2003, 354, 90–93.
(c) Caldwell, H.; Isseponi, S.; Pregosin, P. S.; Albinati, A.; Rizzato, S.
J. Organomet. Chem. 2007, 692, 4043–4051.
(42) There are examples of η6-arene Ru that derive from coordination of
BPh4 anions: (a) Hough, J. J.; Singleton, E. J. Chem. Soc., Chem. Commun.
1972, 371–372. (b) Winter, R. F.; Hornung, F. M. Inorg. Chem. 1997, 36,
6197–6204.
(43) Pregosin, P. S. Coord. Chem. Rev. 2008, 252, 2156–2170.
(44) The corresponding chloride complex [Ru(dppf)(PPh3)(CO)2Cl]BF4
contains cis-CO ligands. See reference 39.

7256 Inorganic Chemistry, Vol. 49, No. 16, 2010
Ledger et al.
Scheme 5
spectroscopic data for 10 has been reported on a number
of occasions,45 we were unable to find either structural or
elemental characterization. An X-ray structure determi-
nation of the cation in 10 is shown in Figure 9 and reveals
a distorted octahedral geometry at the ruthenium center.
In particular, of the phosphorus atoms in the equatorial
˚
belt of the cation, P2 lies 0.99 A below the mean plane
containing P1, P4, P3, and Ru1.46
Conclusions
Treatment of Ru(PPh3)3HCl with xantphos, DPEphos, or
(Ph2PCH2CH2)2O affords the corresponding Ru(P-O-P)-
(PPh3)HCl complexes, which have been shown by X-ray
crystallography to contain tridentate (i.e., “O in”) P-O-P
ligands. The cationic aqua complexes [Ru(P-O-P)(PPh3)-
(H2O)H]þ are formed upon chloride abstraction and readily
coordinate small gaseous ligands to yield [Ru(P-O-P)-
(PPh3)(L)H]þ (L = O2, H2, N2), in which the “O in” binding
mode is retained. Although the dihydrogen and dinitrogen
complexes can only be spectroscopically characterized at low
temperature and are far less stable than when L = O2, metal
fragments capable of binding both O2 and H2 are relatively
rare.47
Attempts to mirror this reactivity of the P-O-P com-
plexeswith the bidentatephosphine ligand dppf result instead
in the formation of the η6-aryl bound phosphine cation
[Ru(dppf){(η6-C6H5)PPh2}H]þ. This shows unexpected re-
activity, eliminating both dppf and PPh3 in favor of a
stronger donor ligand such as PMe3.
Figure 9. Structure of the cation in [Ru(PMe3)5H]BAr4F (10). Thermal
ellipsoids are shown at 30% level. All hydrogen atoms, except Ru-H, are
˚
omitted for clarity. Selected bond lengths (A) and angles (deg): Ru(1)-
P(1) 2.3619(12), Ru(1)-P(2) 2.3774(12), Ru(1)-P(3) 2.3653(11), Ru-
(1)-P(4) 2.3385(13), Ru(1)-P(5) 2.3962(11), P(1)-Ru(1)-P(3)
177.58(4), P(2)-Ru(1)-P(4) 154.02(4), P(1)-Ru(1)-P(5) 91.02(4),
P(2)-Ru(1)-P(5) 104.35(4).
which led to the appearance of a triplet hydride signal in
the 1H{31P} NMR spectrum of 9 at δ -8.56, with a small
cis JHC coupling of 5.6 Hz.
Acknowledgment. Financial support was provided by
the EPSRC (project studentship for AEWL), a Doctoral
Training Award (CEE), and the Swiss National Science
Foundation (AM, PSP). Johnson Matthey plc are ac-
knowledged for the kind loan of hydrated ruthenium
trichloride. We thank Dr John Lowe for assistance with
NMR measurements and simulations and Professor Bob
Morris for valuable discussions.
Addition of a 5-fold excess of PMe3 to a THF solution
of 8 again generated no new products at room tempera-
ture, but upon heating at reflux, afforded two new, highly
coupled hydride containing species, which appeared at
δ -9.25 and -11.35 in the proton NMR spectrum. After
3 h, the product with the lower frequency resonance
was the major product and was assigned as the cationic
penta-trimethylphosphine species [Ru(PMe3)5H]BArF4 (10,
Scheme 5) by comparison with the literature. Although
Supporting Information Available: Experimental and simu-
lated H spectra for reaction of 3b with D2. CIF files giving
1
X-ray crystallographic data for 1a-d, 2a, 3a, 5a-b, 8, and 10.
X-ray structure of [Ru(xantphos)(PPh3)(H2O)H]OTf (CCDC
780098). This material is available free of charge via the Internet
at http://pubs.acs.org.
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