An acidity scale of phosphonium tetraphenylborate salts and ruthenium dihydrogen complexes in dichloromethane

Article abstract of DOI:10.1139/V05-236

Equilibrium constants (K^DM) for reactions between acids and bases of the title compounds in CD₂Cl₂ (DM) have been determined by ³¹P and ¹H NMR spectroscopy at room temperature. [HPCy₃]BPh₄ and [HPCy₃]BF ₄, with pK^DM assigned by literature convention to 9.7, have been used as the anchor compounds for the pK^DM determinations. A continuous scale of pK^DM values covering the range 9.7 to 5.7 is created with the acidic compounds [HPR₃]BPh₄. Those acids with pK^DM greater than 6 are stable, while those with more acidic cations HPR₃⁺ protonate BPh₄^- to produce R₃PBPh₃ and benzene. The literature pK ^THF values reported for [HPBu₂Ph]BPh₄, [HPMePh₂]BPh₄, and [HPEtPh₂]BPh₄ are questionable because of this protonation reaction. NOE and PGSE ¹H NMR techniques are used to show that [HPCy₂Ph]BPh₄ in DM exists as ion pairs and higher aggregates up to quadrupoles at the concentrations used in the acid-base studies. The new dihydrogen complexes [Ru(H₂)Cl(PPh₃)₂(dach)]BF₄ (dach = (1R,2R)-(-)-diaminocyclohexane) and [Ru(H₂)Cl{tmeP ₂(NH)₂}]BF₄ (tmeP₂(NH)₂ = PPh₂C₆H₄CH₂NHCMe ₂CMe₂NHCH₂C₆H₄PPh ₂) were prepared by reaction of RuHCl(PPh₃) ₂(dach) and RuHCl{tmeP₂(NH)₂} with HBF ₄. Their crystal structures are reported, and the pK^DM values of their BPh₄^- salts were determined to be 8.6 and 6.9, respectively.

Full text of DOI:10.1139/V05-236

164
An acidity scale of phosphonium
tetraphenylborate salts and ruthenium dihydrogen
complexes in dichloromethane1
Tianshu Li, Alan J. Lough, Cristiano Zuccaccia, Alceo Macchioni, and
Robert H. Morris
Abstract: Equilibrium constants (KDM) for reactions between acids and bases of the title compounds in CD2Cl2 (DM)
1
have been determined by 31P and H NMR spectroscopy at room temperature. [HPCy3]BPh4 and [HPCy3]BF4, with
pKDM assigned by literature convention to 9.7, have been used as the anchor compounds for the pKDM determinations.
A continuous scale of pKDM values covering the range 9.7 to 5.7 is created with the acidic compounds [HPR3]BPh4.
Those acids with pKDM greater than 6 are stable, while those with more acidic cations HPR3 protonate BPh4 to pro-
+
–
duce R3PBPh3 and benzene. The literature pKTHF values reported for [HPBu2Ph]BPh4, [HPMePh2]BPh4, and
[HPEtPh2]BPh4 are questionable because of this protonation reaction. NOE and PGSE H NMR techniques are used to
1
show that [HPCy2Ph]BPh4 in DM exists as ion pairs and higher aggregates up to quadrupoles at the concentrations
used in the acid–base studies. The new dihydrogen complexes [Ru(H2)Cl(PPh3)2(dach)]BF4 (dach = (1R,2R)-(–)-
diaminocyclohexane) and [Ru(H2)Cl{tmeP2(NH)2}]BF4 (tmeP2(NH)2 = PPh2C6H4CH2NHCMe2CMe2NHCH2C6H4PPh2)
were prepared by reaction of RuHCl(PPh3)2(dach) and RuHCl{tmeP2(NH)2} with HBF4. Their crystal structures are re-
ported, and the pKDM values of their BPh4 salts were determined to be 8.6 and 6.9, respectively.
–
Key words: acidity, dihydrogen complex, hydride, phosphonium, dichloromethane.
Résumé : Opérant à la température et dans le CD2Cl2 (DM) comme solvant et faisant appel à la spectroscopie RMN
1
du H et du 31P, on a déterminé les constantes d’équilibre, KDM, des réactions entres les acides et les bases des compo-
sés mentionnés dans le titre. La valeur de 9,7 attribuée par convention dans la littérature pour les composés
[HPCy3]BPh4 et [HPCy3]BF4 a été utilisé comme composés de référence pour les déterminations des pKDM. On a créé
une échelle continue de valeurs de pKDM s’étalant de 9,7, à 5,7 en faisant appel aux composés acides [HPR3]BPh4. Ces
acides dont les valeurs de pKDM sont supérieures à 6 sont stables alors que ceux des cations plus acides HPR3 se pro-
+
tonent au BPh4 pour conduire à la formation de R3PBPh3 et de benzène. Les valeurs de pKTHF rapportées dans la litté-
–
rature pour les [HPBu2Ph]BPh4, [HPMePh2]BPh4 et [HPEtPh2]BPh4 ne sont pas fiables en raison de cette réaction de
protonation. On a utilisé les techniques d’effet Overhauser nucléaire et d’écho de spin a champ pulsé PGSE en RMN
1
du H pour montrer que dans le DM, aux concentrations utilisées pour les études acide–base, le [HPCy2Ph]BPh4 existe
sous la forme de paire d’ions et d’agrégats plus importants allant jusqu’à des quadrupoles. La réaction du
RuHCl(PPh3)2(dach) et RuHCl{tmeP2(NH)2} avec du HBF4 a permid de préparer les deux nouveaux complexes de di-
hydrogène suivants [Ru(H2)Cl(PPh3)2(dach)]BF4 (dach = (1R,2R)-(–)-diaminocyclohexane) et [Ru(H2)Cl{tmeP2(NH)2}]BF4
(tmeP2(NH)2 = PPh2C6H4CH2NHCMe2CMe2NHCH2C6H4PPh2) dont on a déterminé les structures cristallines et les va-
leurs de pKDM de leurs sels BPh4 qui s’établissent respectivement à 8,6 et 6,9.
–
Mots clés : acidité, complexe de dihydrogène, hydrure, phosphonium, dichlorométhane.
[Traduit par la Rédaction] Li et al. 175
Introduction
derstanding of the reactions of these species in catalytic re-
actions, including those of hydrogenases. Our previous work
focused mainly on the use of tetrahydrofuran (THF) as a
useful solvent in the study of metal hydride and dihydrogen
The quantitative study of the acidity of transition metal
hydride and dihydrogen complexes serves to better the un-
Received 9 June 2005. Published on the NRC Research Press Web site at http:canjchem.nrc.ca on 1 March 2006.
Dedicated to Dr. Arthur Carty, National Science Advisor to the Prime Minister of Canada, for his exemplary contributions to and
support of science in Canada.
T. Li, A.J. Lough, and R.H. Morris.2 Department of Chemistry, University of Toronto, 80 St. George Street, Toronto,
ON M5S 3H6, Canada.
C. Zuccaccia and A. Macchioni. Dipartimento di Chimica, Università di Perugia, Via Elce di Sotto, 8-06123 – Perugia, Italy.
1This article is part of a Special Issue dedicated to Professor Arthur Carty.
2Corresponding author (e-mail: rmorris@chem.utoronto.ca).
Can. J. Chem. 84: 164–175 (2006)
doi:10.1139/V05-236
© 2006 NRC Canada

Li et al.
165
Fig. 1. The acidity ladder of pKDM values of the cationic ruthe-
nium complexes with [HPCy3]BPh4 as a standard.
complexes with a wide range of pK TαHF values (1). The use
of α in this acidity symbol indicates that the effects of ion
pairing on the acid–base equilibria are approximately ac-
counted for by use of the Fuoss equation. This approach has
since been used by Leito and co-workers (2). Tetrahydro-
furan cannot be used as a solvent for very acidic compounds
because it can be protonated and undergo ring-opening reac-
tions. Dichloromethane is a good solvent for this purpose
because it is relatively noncoordinating and it dissolves
many neutral and cationic metal complexes without reaction,
as long as they are not too reducing or nucleophilic. Several
pKDM values of metal hydride and dihydrogen complexes in
CH2Cl2 have been reported by the groups of Jia, Morris, and
co-workers (3–7). Only a short continuous ladder of acids in
the range of 9.7 to 7.0 was built on the basis of equilibria
referenced to [HPCy3]BPh4/PCy3 as a standard with pK =
9.7 (Fig. 1) (4). This is the same reference value used for the
pK TαHF scale (and pseudo pK aaq scale) (4, 8), but it will have
to be redefined when an absolute value is determined rela-
tive to the solvated proton in CH2Cl2. There is no continu-
ous ladder based on cationic acids with exclusively one type
+
-
HPCy3 BPh4
9.7
trans-CpRuH2(dape)+BF4
-
8.5
trans-CpRuH2(dppp)+BPh4
-
8.4
8.3
+
-
trans-CpRuH2(PPh3)2 BPh4
trans-CpRuH2(dppe)+BF4
-
7.3
CpRu(H2)(dppm)+BF4
-
7.1
7.0
CpRu(H2)(dppe)+BF4
-
–
of anion (e.g., BPh4 ) in CD2Cl2. In this study, we make a
–
limited scale of acidic compounds with BPh4 anions. In a
second paper we will describe a more extensive ladder in-
–
volving BF4 salts. Although phosphonium salts are of util-
ity as air-stable sources of air-sensitive trialkylphosphines
(9), we show here that the tetraphenylborate salts of the
more acidic aryl phosphonium compounds are unstable.
We also report the pKDM of two new ruthenium dihy-
drogen trans-to-chloride complexes. These were prepared
while exploring the application of such ruthenium hydrides
for the catalytic hydrogenation of compounds with polar
bonds (10, 11). Cationic ruthenium dihydrogen complexes
have attracted interest with the recent report of Noyori and
co-workers (12) that trans-[Ru(H2)(H)((R)-binap)((R,R)-
dpen)]+ is an intermediate in the asymmetric catalytic H2-
hydrogenation of prochiral ketones catalyzed by
RuH(BH4)((R)-binap)((R,R)-dpen) in isopropanol. Bergens
and co-workers (13) spectroscopically identified this unsta-
ble dihydrogen complex in deuterated isopropanol and re-
ported that at least 1 equiv. of base is necessary to convert
this complex to a catalytically active species.
[3]
[HPR3]BPh4 → C6H6 + PR3·BPh3
There have been scattered reports of the protonation of the
tetraphenylborate anion. Our group encountered it in the pre-
parations of cationic hydrogen isocyanide complexes that
were sometimes produced instead of the complexes
Fe(TIM)(CNBPh3)2 (14) and RuH(CNBPh3)(dppe)2 (15), for
example. This has also been reported by Pombeiro and
co-workers (16) in the preparation of trans-[FeH(CNB-
Ph3)(dppe)2]. The acidic dihydrogen complex [Ir(H2)H-
(triphos)]BPh4 decomposes to IrH3(triphos), BPh3, and ben-
zene (17). However, several cationic dihydrogen and hydride
complexes with tetraphenylborate counterions have been re-
ported (for example, refs. 18–28), and so these are likely to
be less acidic than HPCy2Ph+.
NOE and PGSE NMR measurements of
[HPCy2Ph]BPh4
Results and discussions
Ion pairing in low dielectric constant solvents like CH2Cl2
can lead to changes in reactivity and catalytic activity and
selectivity (29). Table 1 shows the results of the study of
NOE between ions (31) of the compound [HPCy2Ph]BPh4.
Only the meta-aryl hydrogens of the anion (mHa) can be
used as a “reporter”, since the resonances of oHc and oHa
are superimposed. These meta protons are at about the same
distance from both the hydrogen on the phosphorus and the
hydrogen (H1) on each of the two ipso carbons of the
cyclohexyl groups (Fig. 2, Table 1), thus demonstrating the
interpenetration of the cation and anion. It is not surprising
that more acidic salts can readily undergo transfer of the
The preparation of [HPR3]BPh4
The tetrafluoroborate salts [HPR3]BF4 can be readily pre-
pared by protonation of PR3 (PR3 = PCy3, P-n-Bu3, PCy2Ph,
P-t-Bu2Ph) with H(Et2O)BF4 in diethyl ether (eq. [1]). As re-
ported previously (1), these salts react with NaBPh4 in etha-
nol to form the corresponding salts [HPR3]BPh4 (eq. [2]).
However, we found that there is a limitation to this prepara-
+
tion. When the phosphonium salts HPR3 (PR3 = PBu2Ph,
PMe2Ph, PEtPh2, P(p-toly)3, PPh3) are more acidic than
HPCy2Ph+, the borane adducts PR3·BPh3 are isolated instead
of the tetraphenylborate salts [HPR3]BPh4. A phenyl group
–
–
of the BPh4 is protonated to form benzene (eq. [3]). The
phosphorus proton to a phenyl ring carbon of the BPh4 an-
ion, resulting in B—C bond cleavage.
PR3·BPh3 compounds were identified by 31P and H NMR.
1
The pulsed field gradient spin-echo (PGSE) NMR diffu-
sion method (32, 33) is a powerful technique in determining
the solution properties of ion pairs (34–36). From the mea-
[1]
[2]
PR3 + H(Et2O)BF4 → [HPR3]BF4
[HPR3]BF4 + NaBPh4 → [HPR3]BPh4 + NaBF4
© 2006 NRC Canada

166
Fig. 2. H NOESY spectrum of [HPCy2Ph]BPh4 (27 mmol L–1, CD2Cl2, 400 MHz, 299 K).
Can. J. Chem. Vol. 84, 2006
1
Table 1. Experimental NOE (au) and average interionic distances
(<r>exp (Å)) determined using a 27 mmol L–1 solution of
[HPCy2Ph]BPh4 in CD2Cl2 (the distance between pHa and oHa
has been used as reference distance).
tain accurate rH and VH values has been described elsewhere
+
(38). The average hydrodynamic volumes for cation (VH
)
–
and anion (VH ) determined from 1H PGSE experiments
were contrasted with the van der Waals volume of the ion
pair (VIP). The cationic and anionic aggregation numbers (N+
a
Pairs
NOEexp
NOEcorr
<r>exp
–
and N–) were calculated as the ratios VH+/VIP and VH /VIP
pHa/oHa
oHc/P-H
mHa/P-H
oHa/P-H
P-H/H1
2.66
4.02
0.63
1.76
3.48
0.45
0.98
1
4.04b
2.99
4.27
3.60
3.06
5.43
4.47
(Table 2).
6.03
0.71
1.98
5.2
0.17
0.54
The salt [HPCy2Ph]BPh4 in CH2Cl2 forms aggregates
higher than ion pairs even at the lowest concentration inves-
tigated (entry 1, Table 2). The aggregation number for the
cations, N+, is 1.2 and that of the anions, N–, is 1.6, indicat-
ing a dynamic equilibration of ion pairs, triples (e.g.,
mHa/mHc
mHa/H1
–
(HPCy2Ph+)(BPh4 )2), and quadrupoles. The tendency to ag-
aReference 30.
gregate increases as the concentration increases, resulting in
N+ and N– values of 1.8 and 2.0, respectively, at 0.03 mol L–1
(entries 1–3 in Table 2). This is the range of concentrations
used in our acid equilibrium studies, and so, such aggrega-
tion is a potential complication in interpreting our results.
bReference distance.
sured self-diffusion coefficients (Dt), the average hydrody-
namic radius (rH) and volume (VH) of the diffusing particles
were derived, taking advantage of the Stokes–Einstein equa-
tion that relates Dt with 1/rH. TMSS [tetrakis(trimethyl-
silyl)silane], whose rH and VH are known from the literature
(37), was used as internal standard. The methodology to ob-
pKDM determination
The acid (BH+) and base (B) reaction equilibria are built
based on eq. [4]. The equilibrium constants Keq for reactions
© 2006 NRC Canada

Li et al.
167
Fig. 3. An acidity scale ladder of phosphonium tetraphenylborate salts in CD2Cl2 showing pKDM values.
[HPCy3]BPh4
9.7
1.1
8.6 (1)
8.0 (1)
[HPBu3]BPh4
0.6
[HPtBu2Ph]BPh4
1.4
[HPCy2Ph]BPh4
[HPBu2Ph]BPh4
6.6 (3)
5.7 (3)
0.9
Table 2. Diffusion coefficients (D (10–10 m2 s–1)), hydrodynamic radii (rH (Å)), hydrodynamic volumes (VH (Å3)), and aggregation
number values (N) for [HPCy2Ph]BPh4 in CD2Cl2.
Concn. (mmol L–1)
D+
D–
rH
rH
VH
VH
N+
N–
+
–
+
–
Entry
1.5
9
27
850
892
1072
1
2
3
11.1
10.3
9.42
9.90
9.72
9.04
5.37
5.68
6.13
5.88
5.97
6.35
648
767
967
1.19
1.40
1.77
1.56
1.63
1.97
Note: N is the ratio between the experimentally determined hydrodynamic volume and the van der Waals volume of the ion pair; + and – refer to the
cation and anion of [HPCy2Ph]BPh4, respectively.
in CD2Cl2 were measured by use of quantitative 31P{1H} and
1H NMR at room temperature. In view of the PGSE experi-
ments, eq. [4] is a simplification of the actual ion-pairing
equilibria that are present. However the 31P NMR experi-
ment measures the total phosphorus concentration, and these
species are all in rapid equilibrium. If the extent and nature
of ion pairing is the same for B1H+X– and B2H+X–, then
eq. [4] represents a practical, first-order description of the
chemistry. Keq in the range 103 to 10–3 can be measured with
a 10%–30% error. The difference in pKDM between the two
chosen as the anchor for the scale in CD2Cl2, as in the THF
scale (1). Overlapping equilibria were examined with more
acidic compounds to create a continuous ladder of values
(e.g., eqs. [7] and [8]).
[7]
PCy3 + [HBu3]BPh4
[HPCy3]BPh4 + PBu3
pKeq = −1.1
9.7
DM
+
[8]
pK
(HPBu3 ) = 9.7 + pKeq = 8.6
fi
A
short acidity scale ladder of phosphonium
–
–
acids B1H+BPh4 and B2H+BPh4 is calculated from the
tetraphenylborate salts in CD2Cl2 was built by this method
(shown in Fig. 3). The estimated errors for the equilibrium
constants are listed in Tables 3 and 4. The cumulative error
in pKDM value is calculated by eq. [9]. The errors in the last
digit are shown in parentheses in Fig. 3. They represent the
combination of the cumulative errors relative to the refer-
ence value of 9.7 and the estimated errors for Keq.
equilibrium constants (Keq) by use of eq. [5].
Keq
[4]
[5]
B1 + B2H+X–
B1H+X– + B2
∆pKDM = ∆pKeq = pKDM (B1H+X–)
– pKDM (B2H+X–)
(B1H+)
– pK
∆pKDM = ∆pK
= pK
DM
DM
[9]
Cumulative error in pKDM
=
0.08 |pKDM –9.7|
[6]
fi
fi
(B2H+)
DM
The equilibrium constant Keq in the reaction between
HPCy2Ph+ and PBu2Ph has to be obtained by the immediate
measurement of the NMR spectrum after mixing. Right after
mixing, a signal due to HPBu2Ph+ can be observed. Longer
standing (1 h) of the mixture causes a decay of HPBu2Ph+ to
produce the PBu2Ph·BPh3 species (Scheme 1). This suggests
that HPCy2Ph+ with the pKDM value of 6.6 is the most acidic
fi
Ideally, we want the pK
values for the free ions BH+,
DM
fi
independent of the counterion X–, and not the ion-paired
species BH+X– and its aggregates. If the extent of ion pair-
ing is the same for B1H+X– and B2H+X–, then pKDM and
DM
pK
values will be approximately the same (eq. [6]).
[HPCy3]BPh4, with a free ion pK
fi
DM
+
–
(HPCy3 ) = 9.7, was
fi
BPh4 salt that can be obtained.
© 2006 NRC Canada

168
Can. J. Chem. Vol. 84, 2006
Table 3. Equilibrium constants for acid–base reaction of phosphonium salts in CD2Cl2.
Concn.
Concn.
Time to reach
equilibrium (h)
Errora
(%)
(mmol L–1)
Base
(mmol L–1)
Keq
pKeq
Acid
5
5
[HPBu3]BPh4
35
38
43
43
PCy3
33
35
46
43
<4
<4
<1
<1
11.8
4.0
–1.1
–0.6
1.4
[HP-t-Bu2Ph]BPh4
[HP-t-Bu2Ph]BPh4
[HPCy2Ph]BPh4
PBu3
PCy2Ph
10
0.037
PBu2Ph
5
0.12
0.9
aThe error in the equilibrium constant determination is estimated from the magnitude of the constant and the S/N of each species in the spectrum of the
equilibrium mixture.
Table 4. Equilibrium constants for reactions of ruthenium hydride complexes in CD2Cl2.
Concn.
Concn.
Time to reach
equilibrium (h)
Entry Acid (pKDM
)
(mmol L–1)
Base
(mmol L–1)
pKDM
Keq
pKeq
1
2
3
4
5
6
7
8
9
[HP-t-Bu2Ph]BPh4 (8.0)
21
18
RuHCl(PPh3)2(dach)
RuHCl(PPh3)2(dach)
19
16
<1
<1
<1
<1
<1
<1
<1
<1
<1
6
–0.8
8.8
[HPBu3]BPh4 (8.6)
0.65
0.50
153
2.6
0.19 8.4
[Ru(H2)Cl(PPh3)2(dach)]BF4 14
PBu3([HPBu3]BF4 8.2) 18
–0.3
–2.2
–0.4
1.7
8.5
8.8
7.0
6.8
6.9
6.6
6.7
[HPCy2Ph]BPh4 (6.6)
[HPCy2Ph]BPh4 (6.6)
[HPBu3]BPh4 (8.6)
20
16
21
17
21
22
RuHCl(PPh3)2(dach)
RuHCl{tmeP2(NH)2}
RuHCl{tmeP2(NH)2}
RuHCl{tmeP2(NH)2}
RuHCl{tmeP2(NH)2}
RuHCl{tmeP2(NH)2}
18
20
20
20
20
20
0.019
0.08
5.9
[HP-t-Bu2Ph]BPh4 (8.0)
[HPBu2Ph]BF4 (5.8)
[HPCy2Ph]BF4 (6.7)
1.1
–0.8
0
1.0
Scheme 1.
ligand is situated trans to the chloride. The Ru—H distances
to the dihydrogen ligand are both 1.63(5) Å. The H—H dis-
tance is 0.78 (6) Å. Hydrogen-bonding interactions of
F3BF···HN (F···H 2.0 and 2.2 Å) and C4H8O···HN (O···H
2.1 Å) are observed in the X-ray crystal structure.3 The trans
geometry of the complex appears to be maintained in solu-
tion on the basis of the observation of a singlet in the
31P{1H} NMR spectrum. The dihydrogen resonance for this
complex is a singlet at –10.8 ppm, and it is broad because of
PBu2Ph + [HPCy2Ph]BPh4
[HPBu2Ph]BPh4 + PCy2Ph
-C6H6
(10 min)
K = 0.12
Bu2PhP BPh3
(1 h)
The pKDM values of Fig. 3 show the expected substituent
effect of an increase in acidity of the phosphonium with a
change from alkyl to phenyl group. Replacing Cy or Bu by
Ph causes a decrease of approx 3 units of pKDM. The pKDM
values for phosphonium salts with pKDM value greater than
6.5 are in reasonable agreement with the corresponding
pK TαHF values (Fig. 4). However, the reported values (1) of
pK αTHF for [HPBu2Ph]BPh4 (6.7), [HPMePh2]BPh4 (6.3),
and [HPEtPh2]BPh4 (5.3) are questionable, and these equi-
libria may in fact involve the protonation of tetraphenyl-
borate.
2
the rapid dipolar relaxation of the nuclei in the η -
dihydrogen ligand.
The dihydrogen complex [Ru(H2)Cl(PPh3)2(dach)]BF4 in
C6D6 reacts with D2 gas to give isotopomers, including
[Ru(HD)Cl(PPh3)2(dach)]BF4. This probably proceeds via
H–D exchange with the dach N—H bonds. The observation
1
of JHD = 28.5 Hz in the Ru(HD) isotopomer provides more
evidence of the side-on-bonded H2-coordination. This corre-
sponds to an H—H distance of 0.94 Å on the basis of
eq. [10] (39). The X-ray derived value of 0.78(6) Å is proba-
bly underestimated because of the problem of locating hy-
drogen atoms by this method and the rotation of the H2
ligand.
Synthesis and structure of ruthenium dihydrogen
complexes
The complex RuHCl(dach)(PPh3)2 is a precursor to an ac-
tive ketone hydrogen catalyst, RuH2(dach)(PPh3)2 (11). The
protonation of RuHCl(dach)(PPh3)2 by HBF4·Et2O in THF
[10] d(H—H) = –0.0167 (1JHD) + 1.42
2
gives the new dihydrogen complex [Ru(η -H2)Cl(dach)-
Synthesis and structure of [Ru(␩2-H2)Cl{tmeP2(NH)2}]BF4
(PPh3)2]BF4 (Scheme 2). The molecular structure of this
dihydrogen complex is shown in Fig. 5.
2
[Ru(η -H2)Cl{tmeP2(NH)2}]BF4 is observed in the reac-
The overall geometry is octahedral. The ␩2-dihydrogen
tion of RuHCl{tmeP2(NH)2} with HBF4 in CD2Cl2 by NMR
3 Supplementary data for this article are available on the journal Web site (http://canjchem.nrc.ca) or may be purchased from the Depository
of Unpublished Data, Document Delivery, CISTI, National Research Council Canada, Ottawa, ON K1A 0R6, Canada. DUD 4082. For more
information on obtaining material refer to http://cisti-icist.nrc-cnrc.gc.ca/irm/unpub_e.shtml. CCDC 274511 and 274512 contain the crystal-
lographic data for this manuscript. These data can be obtained, free of charge, via www.ccdc.cam.ac.uk/conts/retrieving.html (Or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax +44 1223 336033; or deposit@ccdc.cam.ac.uk).
© 2006 NRC Canada

Li et al.
169
Fig. 4. A comparison of the acidity ladders for [HPR3]BPh4 salts in CD2Cl2 and THF.
DM
THF
pKfi
pKfi
[HPCy3]BPh4
9.7
[HPCy3]BPh4
9.7
8.9
8.1
[HPBu3]BPh4
8.6 (1)
8.0 (1)
[HPBu3]BPh4
[HPtBu2Ph]BPh4
[HPtBu2Ph]BPh4
6.7
6.5
[HPBu2Ph]BPh4
[HPCy2Ph]BPh4
?
[HPCy2Ph]BPh4
[HPBu2Ph]BPh4
6.6 (3)
5.7 (3)
2
Fig. 5. Structure of [Ru(η -H2)Cl(dach)(PPh3)2]BF4·THF as deter-
Scheme 2.
mined by single crystal X-ray diffraction.
+
H
H
H
H2
N
H2
N
H(Et2O)BF4
THF
Ph3P
Ru
Ph3P
Ph3P
-
BF4
Ru
Cl
Ph3P
Cl
N
N
H2
H2
spectroscopy. There are two isomers, A and B, of the RuHCl
complex in the ratio of 3:2 (40). Isomer A is believed to
have two NH hydrogen atoms that are syn to the hydride.
Isomer B has one NH hydrogen atom syn to the hydride and
the other NH hydrogen atom syn to the chloride. Therefore,
two isomers of the Ru dihydrogen complex are formed by
protonation of isomers A and B (shown in Scheme 3).
A crystal of one isomer of the dihydrogen complexes was
obtained from the reaction. The molecular structure of the
dihydrogen complex (Fig. 6) is derived from isomer B with
one NH hydrogen atom syn to the chloride. The distances
Ru—H1 and Ru—H2 are 1.79(2) and 1.79(3) Å, respec-
tively. These long Ru—H distances might signal a weak
Ru—H2 interaction, and this interaction might explain why
the dihydrogen ligand is usually lost during isolation. There
is an intramolecular electrostatic NH···Cl interaction ob-
served in the structure with an H···Cl distance of 2.5 Å.
2
[Ru(η -H2)Cl(dach)(PPh3)2]BF4 has an NH···Cl distance of
2.8 Å. The other NH hydrogen atom is syn to the dihydro-
gen ligand and hydrogen bonds with the BF4 anion (NH···F
distance of 2.0 Å). The 31P NMR spectrum suggests that two
isomers are formed in the ratio of 1:2 (A:B). Isomer A
exhibits a singlet at 36.4 ppm. Isomer B exhibits two dou-
blets at 40.6 and 30.5 ppm. The dihydrogen resonance for this
complex is similar to that of [Ru(␩2-H2)Cl(dach)(PPh3)2]+ and
exhibits a broad singlet at –10.9 ppm. [Ru(HD)Cl{tmeP2-
(NH)2}]BF4 was prepared by the reaction of
RuHCl{tmeP2(NH)2} and HBF4–D2O in CD2Cl2. The obser-
vation of JHD = 28 Hz in the Ru(HD) isotopomer suggests
an H—H distance of 0.95 Å on the basis of eq. [10]. When
1
© 2006 NRC Canada

170
Can. J. Chem. Vol. 84, 2006
Scheme 3.
Fig. 6. Structure of [Ru(H2)Cl{tmeP2(NH)2}] BF4 as determined
by single crystal X-ray diffraction.
+
H
H
H
H
H H
Ru
H(Et2O)BF4
CD2Cl2
H
N
N
N
N
-
BF4
Ru
Cl
A
P
P
P
P
Cl
Ph2
Ph2
Ph2
Ph2
H
+
H
H
N
N
H(Et2O)BF4
CD2Cl2
H
H
N
N
H
H
Ru
Cl
B
-
BF4
Ru
Cl
P
P
Ph2
Ph2
P
P
Ph2
Ph2
[Ru(␩2-H2)Cl{tmeP2(NH)2}]BF4 reacts with D2, there is no
1
hydride signal in the H NMR spectrum, consistent with the
2
formation of [Ru(η -D2)Cl{tmeP2(NH)2}]BF4. Apparently
there is no D–H exchange between D2 and the NH groups.
The pKDM measurements for the dihydrogen complexes
The equilibria between the hydrido complexes
RuHCl(dach)(PPh3)2 or RuHCl{tmeP2(NH)2} and the phos-
phonium salts were established within 1 h at 20 °C (Figs. 7
and 8 ). The equilibria involving the BPh4– salts [HPBu3]BPh4,
[HP-t-Bu2Ph]BPh4, and [HPCy2Ph]BPh4 produced an
pyridine donor is more like a phosphine than an amine on
ruthenium.
average pKDM value of 8.6 0.2 for the dihydrogen complex
2
[Ru(η -H2)Cl(dach)(PPh3)2]BPh4.
A corresponding reaction
with [HPBu3]BF4 gave a pKDM value of 8.5 0.2 for the
corresponding BF4 salt of the dihydrogen complex. The
Conclusions
–
A
continuous acidity ladder of five phosphonium
variation in the values obtained could be a result of ion-
tetraphenylborate salts in CD2Cl2 at room temperature has
now been established by use of 31P NMR spectroscopy. The
pKDM values are generally consistent with values previously
measured in THF. NOE and PGSE measurements show that
ion pairs and higher aggregates are present in solution, com-
plicating the interpretation of the results. When the pKDM is
pairing effects and NH···FBF3– hydrogen bonding in the case
–
of equilibria involving the BF4 anion.
Three equilibria were established between RuHCl-
{tmeP2(NH)2} and phosphonium tetraphenylborate salts
[HPBu3]BPh4, [HP-t-Bu2Ph]BPh4, and [HPCy2Ph]BPh4, to
2
give a consistent pKDM value of 6.9 for [Ru(η -H2)Cl-
–
lower than 6.6, the BPh4 salts tend to decompose. The acid-
{tmeP2(NH)2}]BPh4. Two equilibria between RuHCl-
{tmeP2(NH)2} and [HPBu2Ph]BF4 and [HPCy2Ph]BF4 sug-
ities of the new dihydrogen complexes, [Ru(H2)Cl(PPh3)2-
(dach)]BPh4 and [Ru(H2)Cl{tmeP2(NH)2}]BPh4, are
determined to be pKDM 8.6 and 6.9, respectively, through the
use of several consistent equilibria with phosphonium salts.
2
gest an average pKDM value of 6.7 for [Ru(η -H2)Cl-
{tmeP2(NH)2}]BF4.
–
The pKDM values for the BF4 salts are similar. The crystal
Comparison of the acidity of ruthenium dihydrogen
complexes
structures of [Ru(H2)Cl(PPh3)2(dach)]BF4 and [Ru(H2)Cl-
{tmeP2(NH)2}]BF4 are determined. We will describe else-
where the use of tetrafluoroborate salts to extend the ladder
to lower pKDM values, below the limit set by the decomposi-
The pKDM values of some related dihydrogen complexes
are listed in Table 5. The complexes [Ru(H2)Cl(dppe)2]PF6
and [Ru(H2)Cl(dppp)2]PF6 are dihydrogen complexes with
four phosphorus (phosphine) donors and have pKDM values
of approximately 4.7 and 3.3, respectively (entries 1 and 2,
Table 5) (41, 42).4 [Ru(H2)Cl{tmeP2(NH)2}]BPh4 and
–
tion of BPh4 salts.
Experimental
[Ru(H2)Cl(dach)(PPh3)2]BPh4 are
a different class of
General methods
dihydrogen complex with two phosphorus (phosphine) and
two nitrogen (amine) ligands, and they have pKDM 6.9 and
8.6, respectively (entries 4 and 5, Table 5). The replacement
of phosphine ligands with more electron-donating amine lig-
ands decreases the acidity of the complexes. However,
[Ru(H2)Cl(PPh3)(PMP)]BF4 with three phosphorus (phos-
phine) ligands and one nitrogen (pyridyl) ligand (6) does not
follow this trend (entry 3, Table 5), suggesting that the
All preparations and manipulations were carried out under
hydrogen, nitrogen, or argon atmospheres with the use of
standard Schlenk, vacuum line, and glovebox techniques in
dry, oxygen-free solvents. Tetrahydrofuran (THF), diethyl
ether (Et2O), and hexanes were dried and distilled from so-
dium benzophenone ketyl. Dichloromethane was dried and
distilled from calcium hydride. Deuterated solvents were de-
gassed and dried over activated molecular sieves. NMR
4 T. Li, A.J. Lough, and R.H. Morris. In preparation.
© 2006 NRC Canada

Li et al.
171
Fig. 7. The equilibria established between RuHCl(dach)(PPh3)2 and phosphonium salts in 1 h at 20 °C.
9.7
[HPCy3]BPh4
[HPBu3]BPh4
+
-
8.6(1)
PBu3
+
RuHCl(dach)(PPh3)2
RuH2Cl(dach)(PPh3)2 BPh4
+
pKDM = 8.4(1)
Keq = 0.65 pKeq = 0.2
8.2(2)
[HPBu3]BF4
+
-
PBu3
RuH2Cl(dach)(PPh3)2 BF4
[HPBu3]BF4
+
+
RuHCl(dach)(PPh3)2
pKDM = 8.5(2)
Keq = 0.50 pKeq = 0.2
[HPtBu2Ph]BPh4
[HPCy2Ph]BPh4
+
-
PtBu2Ph
8.0(2)
6.6(3)
+ RuHCl(dach)(PPh3)2
RuH2Cl(dach)(PPh3)2 BPh4
+
pKDM = 8.8(2)
Keq = 6 pKeq = -0.8
+
-
+
RuHCl(dach)(PPh3)2
Keq = 153 pKeq = -2.2(2)
RuH Cl(dach)(PPh ) BPh
+
PCy2Ph
2
3 2
4
pKDM = 8.6(5)
Table 5. Comparison of the acidity of ruthenium dihydrogen complexes.
Entry
Type
Complex
pKDM
Ref.
a
b
1
2
3
4
5
[RuP4(H2)Cl]X
[Ru(H2)Cl(dppe)2]PF6
4.7
3.3
4.0 d
6.9
8.6
42
41
6
[Ru(H2)Cl(dppp)2]PF6
c
[RuP3N(H2)Cl]X
[RuP2N2(H2)Cl]X
[Ru(H2)Cl(PPh3)(PMP)]BF4
[Ru(H2)Cl{tmeP2(NH)2}]BPh4
This work
This work
–
[Ru(H2)Cl(dach)(PPh3)2]BPh4
adppe = 1,2-bis(diphenylphosphine)ethane.
bdppp = 1,3-bis(diphenylphosphine)propane.
cPMP = 2,6-(Ph2PCH2)2C5H3N.
dThe literature value of 5.1 has been adjusted (42).
spectra were recorded on a Varian Unity-500 (500 MHz for
been found to have the correct elemental analyses by the
Analyst Laboratory of the University of Toronto.
1
1H), a Varian Unity-400 (400 MHz for H), or on a Varian
Gemini 300 MHz spectrometer (300 MHz for 1H and
121.5 MHz for 31P). All 31P chemical shifts were measured
relative to 10% P(OMe)3 in C6D6. This reference solution
was placed in a 2 mm capillary tube inside the 5 mm sample
[HPR3]BPh4
All phosphonium salts [HPR3]BPh4 (PR3 = PCy3, P-n-
Bu3, P-t-Bu2Ph, PCy2Ph) were isolated by use of the re-
ported preparation (4), with typical yields of 80%–90%. The
attempted preparations of [HPR3]BPh4 (PR3 = PBu2Ph,
PMe2Ph, PEtPh2, PPh3) were unsuccessful as these decom-
pose. PR3·BPh3 (PR3 = PBu2Ph, PMe2Ph, PEtPh2, PPh3)
compounds were obtained instead. The 31P NMR chemical
shifts are reported in Table 6. NMR data for [HPCy2Ph]BPh4
(CD2Cl2, 299 K, J values in Hz, refer to Fig. 2 for the label-
ling) follow.
1
NMR tube. H chemical shifts were measured relative to
partially deuterated solvent peaks but are reported relative to
tetramethylsilane. The phosphine compounds were received
from commercial suppliers (Aldrich Chemical Co., Stem
Co.) and used without further purification. NaBPh4 was sup-
plied by Aldrich Chemical Co. RuCl3 hydrate was obtained
from Johnson Matthey. The compounds RuHCl(PPh3)2-
(dach) (10) and trans-RuHCl{tmeP2(NH)2} (40) were pre-
pared according to literature procedures. Protonated salts
that have not already been reported in the literature have
3
3
1H NMR δ: 7.83 (t, JHH = 7.7, pHc), 7.64 (td, JHH = 7.8,
4JHP = 3.3, mHc), 7.39 (m, oHa), 7.36 (dd, JPH = 19.4,
3
© 2006 NRC Canada

172
Can. J. Chem. Vol. 84, 2006
Fig. 8. The equilibria established between RuHCl{tmeP2(NH)2} and the phosphonium salt in 1 h at 20 °C.
9.7
[HPCy3]BPh4
[HPBu3]BPh4
RuH2Cl{tmeP2(NH)2}+
8.6(1)
PBu3
+
RuHCl{tmeP2(NH)2}
+
Keq = 0.019 pKeq = 1.7(1)
pKDM = 6.9(2)
[HPtBu2Ph]BPh4
PtBu2Ph
+
RuH2Cl{tmeP2(NH)2}+
8.0(1)
+ RuHCl{tmeP2(NH)2}
Keq = 0.08 pKeq = 1.1
pKDM = 6.9(1)
RuH Cl{tmeP (NH) }+
6.7(2)
6.6(3)
5.8(3)
[HPCy2Ph]BF4
+ RuHCl{tmeP2(NH)2}
Keq = 1 pKeq = 0
pKDM = 6.7(2)
PCy2Ph +
2
2
2
RuH2Cl{tmeP2(NH)2}+
[HPCy2Ph]BPh4 + RuHCl{tmeP2(NH)2}
Keq = 2.6 pKeq = -0.4
pKDM = 7.0(3)
+
+
PCy2Ph
RuH Cl{tmeP (NH) }+
[HPBu2Ph]BF4
+ RuHCl{tmeP2(NH)2}
Keq = 5.9 pKeq = -0.8
pKDM = 6.6(3)
PCy2Ph
2
2
2
Table 6. 31P NMR chemical shifts of phosphines and
phosphonium salts in CD2Cl2.
3
3
3JHH = 7.8, oHc), 7.09 (t, JHH = 7.5, mHa), 6.95 (tt, JHH
=
4
1
3
7.3, JHH = 1.3 pHa), 5.08 (dt, JPH = 471.0, JHH = 6.3, P-
H), 2.30 (m, H1), 1.81, 1.66, 1.35, 1.15 (m, cyclohexyl reso-
nances).
Bases
PCy3
δ
31P
9.8
Acids
δ
31P
[HPCy3]BPh4
[HPCy3]BF4
29.5
29.5
10.7
52.3
27.1
27.0
14.9
–4.4
2.0
[Ru(H2)Cl(PPh3)2(dach)]BF4
PBu3
–31.1
39.4
2.9
[HPBu3]BPh4
[HP-t-Bu2Ph]BPh4
[HPCy2Ph]BPh4
[HPCy2Ph]BF4
[HPBu2Ph]BF4
PBu2Ph·BPh3
[HPMePh2]BF4
PMePh2·BPh3
[HPEtPh2]BF4
PEtPh2·BPh3
RuHCl(PPh3)2(dach) (203 mg, 0.26 mmol) was dissolved
in THF (2 mL). HBF4 (54 wt% in Et2O, 90 mg, 0.30 mmol)
was added to the solution under Ar and stirred for 0.5 h.
Et2O (6 mL) was added to give a yellow-green precipitate.
The solid was filtered and washed with diethyl ether (2 ×
3 mL). The solid product was obtained by filtration and
dried under vacuum. Crystals of [Ru(H2)Cl(PPh3)2(dach)-
]BF4 were prepared by slow diffusion of diethyl ether into a
saturated solution of the complex in THF. Yield: 190 mg,
P-t-Bu2Ph
PCy2Ph
PBu2Ph
PMePh2
PEtPh2
–24.6
–27.1
–11.8
–9.5
12.5
–4.0
1
87%. H NMR (C6D6) δ: 7.4–7.0 (m, 30H, Ph), 3.3 (br, 2H,
NH2), 2.8–2.6 (m, 8H, CH2), 2.2 (br, 2H, NH2), 1.2 (m, 2H,
CH), –10.75 (br, 2H, RuH2). 31P NMR δ: 46.1 (s). Anal.
© 2006 NRC Canada

Li et al.
173
calcd. for C42H46N2P2BClF4Ru: C 58.08, H 5.46, N 3.33;
found: C 58.40, H 5.33, N 3.24.
NOE measurements
1
The H NOESY NMR experiment was acquired by the
standard three-pulse sequence (43). Each transient (direct di-
mension) was acquired using 2K points; the number of tran-
sients (indirect dimension) was 1K, and the number of scans
was set at 16. A relaxation delay of 2 s and a mixing time of
0.5 s were used. The average interionic distances were ob-
tained taking into account that the volumes of the NOE cross
peaks are proportional to (nInS/nI+nS), where nI and nS are
the number of equivalent I and S nuclei, respectively (30).
The reaction of RuHCl{tmeP2(NH)2} with HBF4
A
mixture of two isomers (see Discussion) of
RuHCl{tmeP2(NH)2} (10 mg, 0.012 mmol) was dissolved in
CD2Cl2 (1 mL) in an NMR tube under Ar. HBF4 (54 wt% in
1
Et2O, 10 mg, 0.06 mmol) was added to the solution. H
NMR δ: 7.6–6.8 (m, 28H, Ph), 4.8 (m, CH2), 4.6 (m, CH2),
4.4 (m, NH), 3.9 (m, NH), 1.8–1.2 (m, 12H, CH3), –10.9
(brs, 2H, RuH2); T1 = 19 ms at 400 MHz NMR spectrometer
PGSE measurements
2
at 293 K. 31P NMR δ: 41.0 (d, JPP = 25 Hz, 40%, isomer
1H PGSE NMR measurements were performed using the
standard stimulated echo pulse sequence (32) on a Bruker
AVANCE DRX 400 spectrometer equipped with a GREAT
1/10 gradient unit and a QNP probe with a Z-gradient coil,
at 299 K without spinning. The shape of the gradients was
rectangular, their duration was 5 ms, and their strength (G)
was varied during the experiments. All the spectra were ac-
quired using 32K points, a spectral width of 5000 Hz, and
processed with a line broadening of 1.0 Hz. The semilo-
garithmic plots of ln(I/I0) vs. G2 (where I and I0 are the in-
tensities of the observed spin echo in the presence or in the
absence of the field gradient, respectively) (34, 35) were fit-
ted using a standard linear regression algorithm; the R factor
was always higher than 0.99. rH, VH, and N values were de-
rived from experimentally determined Dt data as described
in ref. 31.
B), 30.5 (d, 37%, isomer B), 37.0 (s, 23%, isomer A). Crys-
tals of [Ru(H2)Cl{tmeP2(NH)2}]BF4 were prepared by slow
diffusion of diethyl ether into the NMR solution of the com-
plex in CD2Cl2 under Ar.
The reaction of [Ru(H2)Cl(PPh3)2(dach)]BF4 with D2
[Ru(H2)Cl(PPh3)2(dach)]BF4 (10 mg, 0.011 mmol) was
dissolved in C6D6 (1 mL) in a 5 mm NMR tube under Ar.
The solution was frozen in liquid N2 and degassed – refilled
with D2 gas for three cycles. The NMR tube was sealed with
a flame under D2 and warmed up to room temperature. An
1H NMR spectrum was collected immediately and after
15 h. A 1:1:1 triplet of 1:2:1 triplets at –10.74 ppm (1JHD
28.5 Hz, JHP = 8.7 Hz) was observed over time due to
=
2
Ru(HD).
X-ray diffraction structure determination of [Ru(H2)Cl-
(PPh3)2(dach)]BF4 and [Ru(H2)Cl{tmeP2(NH)2}]BF4
Crystals suitable for X-ray diffraction were obtained by
vapor diffusion. Data were collected on a Nonius Kappa-
CCD diffractometer using monochromated Mo Kα radiation
and were measured using a combination of φ scans and ω
scans with κ offsets, to fill the Ewald sphere. The data were
processed using the Denzo-SMN package (44). For the sec-
ond structure (the tmeP2(NH)2 complex), absorption correc-
tions were carried out using SORTAV (45). The structures
were solved and refined using SHELXTL V6.1 (46) for full-
matrix least-squares refinements that are based on F2. The H
atoms of the dihydrogen were refined independently with
isotropic displacement parameters, but in the first structure
these parameters were tied to the Ueq values of the Ru at-
oms. All other H atoms were included in calculated posi-
tions and allowed to refine in riding-motion approximation
with Uiso tied to the carrier atom. Crystallographic data for
the compounds are given in Tables 7 and 8, and selected
bond distances and angles in Tables 9 and 10.
The reaction of [Ru(H2)Cl{tmeP2(NH)2}]BF4 with D2
The procedure used for the dach complex was followed.
No H–D coupling was observed. The hydride signal at
–10.9 ppm disappeared after 15 h.
The reaction of RuHCl{tmeP2(NH)2} with HBF4(Et2O)–D2
RuHCl{tmeP2(NH)2} (isomer A, 10 mg, 0.012 mmol) was
dissolved in CD2Cl2 (1 mL) in an NMR tube. DBF4 (1 drop,
prepared by mixing HBF4, 54 wt% in Et2O, 0.40 g,
0.025 mol and degassed D2O, 1.1 g, in a Schlenk flask) was
added to the solution. A 1:1:1 triplet of triplets was observed
1
over time due to Ru(HD). H NMR δ: –10.9 (tt, RuHD,
2
2
1JHD = 28.5 Hz, JHP = 8.4 Hz). 31P NMR δ: 40.6 (d, JPP
=
25 Hz, isomer B), 30.5 (d, isomer B).
Determination of equilibrium constants in CD2Cl2
Solutions of samples were mixed under N2 as described in
Tables 3 and 4. In general, equilibrium constants were deter-
1
mined by H and 31P{1H} NMR. Usually, signals for all of
the species in equilibrium could be located and integrated in
the 31P{1H} NMR and, in the case of hydride complexes, in
the H NMR spectra as well. The chemical shifts for the
Acknowledgment
1
pure phosphines and phosphonium salts (Table 6) were de-
termined and referenced to the P(OMe)3 standard at
141.5 ppm. In some cases, when the chemical shifts of two
species are very similar, mass-balance arguments can be
used to estimate the equilibrium concentration of the species
from their starting concentrations. Thermodynamic data for
the equilibria in CD2Cl2 are shown in Tables 3 and 4.
This work was supported by a discovery grant to RHM
from the Natural Sciences and Engineering Research Coun-
cil of Canada (NSERC) and by a grant to AM from the
Ministero dell’Istruzione, dell’Università e della Ricerca
(MUIR) (PRIN 2004-2005). We thank J. Matthey for a loan
of ruthenium salts and Dr. K. Abdur-Rashid for assistance
with some experiments.
© 2006 NRC Canada

174
Can. J. Chem. Vol. 84, 2006
2
Table 7. Crystallographic data for [Ru(η H2)Cl(dach)-
Table 8. Crystallographic data for [Ru(H2)Cl{tmeP2(NH)2}]BF4.
(PPh3)2]BF4·THF.
a (Å)
14.7990(3)
Formula
C44H48BClF4N2P2Ru
a (Å)
12.0771(5)
Formula
C46H54N2P2BClF4ORu
b (Å)
c (Å)
α (°)
12.6530(3)
21.7310(4)
90
92.670(1)
90
Formula weight 890.11
b (Å)
c (Å)
α (°)
β (°)
γ (°)
12.2479(4)
16.5468(5)
70.917(2)
89.536(2)
69.588(2)
Formula weight 936.18
Space group
T (K)
Space group
P21/c
P1
T (K)
150(1)
0.710 73
1.455
100(1)
0.710 73
1.445
β
γ
(°)
(°)
λ
(Å)
λ (Å)
(mg/m3)
ρcalc
ρcalc (mg/m3)
V (Å3)
4064.8(2)
4
R1 (all data)
0.074
0.109
V (Å3) 2152.28(13)
R1 (all data)
0.071
0.123
Z
wR2
Z
2
wR2
2
Table 9. Selected bond distances and angles for [Ru(η -H2)Cl(dach)(PPh3)2]BF4.
Distances (Å)
Ru(1)—H(1Ru)
H(1Ru)—H(2Ru)
Ru(1)—P(2A)
1.63(5)
0.78(6)
2.3537(8)
2.19(1)
Ru(1)—H(2Ru)
Ru(1)—P(1A)
Ru(1)—N(1A)
Ru(1)—Cl(1)
1.63(5)
2.3242(8)
2.17(1)
Ru(1)—N(2A)
2.4143(8)
Angles (°)
H(1Ru)-Ru(1)-H(2Ru)
H(2Ru)-Ru(1)-N(1)
H(2Ru)-Ru(1)-N(2)
P(1)-Ru(1)-P(2)
N(2)-Ru(1)-P(1)
N(2)-Ru(1)-P(2)
H(2Ru)-Ru(1)-Cl(1)
P(2)-Ru(1)-Cl(1)
N(2)-Ru(1)-Cl(1)
27(2)
103(2)
70(2)
98.14(3)
167.1(2)
93.9(2)
164(2)
91.43(3)
87.2(4)
H(1Ru)-Ru(1)-N(1)
H(1Ru)-Ru(1)-N(2)
N(1)-Ru(1)-N(2)
N(1)-Ru(1)-P(1)
N(1)-Ru(1)-P(2)
H(1Ru)-Ru(1)-Cl(1)
P(1)-Ru(1)-Cl(1)
N(1)-Ru(1)-Cl(1)
81(2)
90(2)
78.1(3)
90.4(2)
169.7(4)
163(2)
96.94(3)
81.9(5)
Table 10. Selected bond distances and angles for [Ru(H2)Cl{tmeP2(NH)2}]BF4.
Distances (Å)
Ru(1)—H(1Ru)
Ru(1)—H(2Ru)
Ru(1)—N(2)
1.79(2)
1.79(3)
2.150(2)
2.175(2)
Ru(1)—P(2)
Ru(1)—P(1)
Ru(1)—Cl(1)
2.3205(8)
2.3412(7)
2.4210(8)
Ru(1)—N(1)
Angles (°)
H(1Ru)-Ru(1)-H(2Ru)
H(1Ru)-Ru(1)-N(2)
H(2Ru)-Ru(1)-N(2)
H(1Ru)-Ru(1)-N(1)
H(2Ru)-Ru(1)-N(1)
N(2)-Ru(1)-N(1)
H(1Ru)-Ru(1)-P(2)
H(2Ru)-Ru(1)-P(2)
N(2)-Ru(1)-P(2)
N(1)-Ru(1)-P(2)
H(1Ru)-Ru(1)-P(1)
19(2)
85(2)
100(2)
90(2)
82(2)
78.05(9)
86(2)
H(2Ru)-Ru(1)-P(1)
N(2)-Ru(1)-P(1)
N(1)-Ru(1)-P(1)
P(2)-Ru(1)-P(1)
H(1Ru)-Ru(1)-Cl(1)
H(2Ru)-Ru(1)-Cl(1)
N(2)-Ru(1)-Cl(1)
N(1)-Ru(1)-Cl(1)
P(2)-Ru(1)-Cl(1)
P(1)-Ru(1)-Cl(1)
81(2)
170.38(7)
92.48(6)
97.81(3)
165(2)
174(2)
81.39(7)
91.86(7)
89.52(3)
97.41(3)
97(2)
91.73(7)
169.35(6)
97(2)
References
4. G. Jia and R.H. Morris. J. Am. Chem. Soc. 113, 875 (1991).
5. G. Jia and R.H. Morris. Inorg. Chem. 29, 581 (1990).
6. G. Jia, H.M. Lee, I.D. Williams, C.-P. Lau, and Y. Chen.
Organometallics, 16, 3941 (1997).
1. K. Abdur-Rashid, T.P. Fong, B. Greaves, D.G. Gusev, J.G.
Hinman, S.E. Landau, A.J. Lough, and R.H. Morris. J. Am.
Chem. Soc. 122, 9155 (2000).
7. G. Jia and C.-P. Lau. Coord. Chem. Rev. 190–192, 83 (1999).
8. S.S. Kristjansdottir, A.J. Loendorf, and J.R. Norton. Inorg.
Chem. 30, 4470 (1991).
2. I. Kaljurand, T. Rodima, A. Pihl, V. Mämets, I. Leito, I.A.
Koppel, and M. Mishima. J. Org. Chem. 68, 9988 (2003).
3. G. Jia, R.H. Morris, and C.T. Schweitzer. Inorg. Chem. 30,
593 (1991).
9. M. Netherton and G. Fu. Org. Lett. 3, 4295 (2001).
© 2006 NRC Canada

Li et al.
175
10. K. Abdur-Rashid, A.J. Lough, and R.H. Morris. Organo-
metallics, 19, 2655 (2000).
D.A. Hoyos, R. Llusar, S. Uriel, and C. Vicent. J. Chem. Soc.
Dalton Trans. 530 (2004).
11. R. Abbel, K. Abdur-Rashid, M. Faatz, A. Hadzovic, A.J.
Lough, and R.H. Morris. J. Am. Chem. Soc. 127, 1870 (2005).
12. C.A. Sandoval, T. Ohkuma, K. Muñiz, and R. Noyori. J. Am.
Chem. Soc. 125, 13490 (2003).
13. R.J. Hamilton, C.G. Leong, G. Bigam, M. Miskolzie, and S.H.
Bergens. J. Am. Chem. Soc. 127, 4152 (2005).
14. P.I. Amrhein, A.J. Lough, and R.H. Morris. Inorg. Chem. 35,
4523 (1996).
28. T. Takao, S. Yoshida, and H. Suzuki. Chem. Lett. 138, 1100
(2001).
29. A. Macchioni. Chem. Rev. 105, 2039 (2005).
30. S. Macura and R.R. Ernst. Mol. Phys. 41, 95 (1980).
31. A. Macchioni. Eur. J. Inorg. Chem. 195 (2003).
32. P. Stilbs. Prog. Nucl. Magn. Reson. Spectrosc. 19, 1 (1987).
33. C.S. Johnson, Jr. Prog. Nucl. Magn. Res. Spectrosc. 34, 203
(1999).
15. E. Rocchini, P. Rigo, A. Mezzetti, T. Stephan, R.H. Morris,
A.J. Lough, C.E. Forde, T.P. Fong, and S.D. Drouin. J. Chem.
Soc. Dalton Trans. 3591 (2000).
34. M. Valentini, H. Rüegger, and P.S. Pregosin. Helv. Chim. Acta,
84, 2833 (2001).
35. B. Binotti, A. Macchioni, C. Zuccaccia, and D. Zuccaccia.
16. S.S.P.R. Almeida, M.F.C. Guedes da Silva, J.J.R. Fraùsto da
Silva, and A.J.L. Pombeiro. J. Chem. Soc. Dalton Trans. 467
(1999).
Comments Inorg. Chem. 23, 417 (2002).
36. E. Martinez-Viviente, P.S. Pregosin, L. Vial, C. Herse, and J.
Lacour. Chem. Eur. J. 10, 2912 (2004).
17. C. Bianchini, S. Moneti, M. Peruzzini, and F. Vizza. Inorg.
37. R.E. Dinnebier, W.A. Dollase, X. Helluy, J. Kümmerlen, A.
Sebald, M.U. Schmidt, S. Pagola, P.W. Stephens, and S. van
Smaalen. Acta Crystallogr. Sect. B, B55, 1014 (1999).
38. D. Zuccaccia and A. Macchioni. Organometallics, 24, 3476
(2005).
Chem. 36, 5818 (1997).
18. A. Albinati, W. Klooster, T.F. Koetzle, J.B. Fortin, J.S. Ricci,
J. Eckert, T.P. Fong, A.J. Lough, R.H. Morris, and A.
Golombek. Inorg. Chim. Acta, 259, 351 (1997).
19. J.S. Ricci, T.F. Koetzle, M.T. Bautista, T.M. Hofstede, R.H.
Morris, and J.F. Sawyer. J. Am. Chem. Soc. 111, 8823 (1989).
20. M.G. Basallote, M. Besora, J. Durán, M.J. Fernández-Trujillo,
A. Lledós, M.A. Máñez, and F. Maseras. J. Am. Chem. Soc.
126, 2320 (2004).
21. C. Bianchini, D. Masi, M. Peruzzini, M. Casarin, C. Maccato,
and G.A. Rizzi. Inorg. Chem. 36, 1061 (1997).
22. D.L. Hughes, G.J. Leigh, and C.N. McMahon. J. Chem. Soc.
Dalton Trans. 909 (1999).
39. K.A. Earl, G. Jia, P.A. Maltby, and R.H. Morris. J. Am. Chem.
Soc. 113, 3027 (1991).
40. T. Li, R. Churlaud, A. Lough, K. Abdur-Rashid, and R.H.
Morris. Organometallics, 23, 6239 (2004).
41. E. Rocchini, A. Del Zotto, P. Martinuzzi, P. Rigo, A. Mezzetti,
H. Rüegger, U. Burckhardt, and V. Gramlich. Inorg. Chem. 36,
711 (1997).
42. B. Chin, A.J. Lough, R.H. Morris, C.T. Schweitzer, and C.
D’Agostino. Inorg. Chem. 33, 6278 (1994).
23. M. Jimenez-Tenorio, M.C. Puerta, and P. Valerga. J. Chem.
Soc. Chem. Commun. 1750 (1993).
43. J. Jeener, B.H. Meier, P. Bachmann, and R.R. Ernst. J. Chem.
Phys. 71, 4546 (1979).
24. R.M. Henry, R.K. Shoemaker, R.H. Newell, G.M. Jacobsen,
D.L. DuBois, and M. Rakowski DuBois. Organometallics, 24,
2481 (2005).
44. Z.M. Otwinowski and W. Minor. In Methods in enzymology.
Edited by C.W. Carter and R.M. Sweet. Academic Press, Lon-
don. 1997. pp. 307.
25. J.A. Ayllon, S.F. Sayers, B. Donnadieu, B. Chaudret, and E.
45. R.H. Blessing. Acta Cryst. A51, 33 (1995).
46. G.M. Sheldrick. SHELXTL/PC. Version 6.1 [computer pro-
gram] Windows NT Version. Bruker AXS Inc., Madison, Wis-
consin. 2001.
Clot. Organometallics, 18, 3981 (1999).
26. F. Estevan, M. Feliz, R. Llusar, J.A. Mata, and S. Uriel. Poly-
hedron, 20, 527 (2001).
27. M.G. Basallote, F. Estevan, M. Feliz, M.J. Fernández-Trujillo,
© 2006 NRC Canada