Air-stable ruthenium(II) and osmium(II) fluoride complexes. Crystal structures of [OC-6-13][MF2(CO)2(PR3)2] [M = Ru, PR3 = PEtPh2; M = Os, PR3 = PPh3 or P(C6H11)3]

Article abstract of DOI:10.1039/a702142i

The reaction of Lewis bases L with [{MF₂(CO)₃}₄] (M = Ru or Os) in organic solvents provided a clean, high-yield, route to a series of air- and moisture-stable ruthenium(II) and osmium(II) fluoride co-ordination compounds of general formulae [MF₂(CO)₂L₂]. Characterisation by elemental analysis, FAB mass spectrometry, NMR and IR spectroscopy indicated a cis,cis,trans ligand arrangement. The crystal structures of [OC-6-13]-[MF₂(CO)₂(PR₃)₂] [M = Ru, PR₃ = PEtPh₂; M = Os, PR₃ = PPh₃ or P(C₆H₁₁)₃] have been determined by X-ray crystallography. The geometry about the central metal atoms for all three structures is distorted pseudooctahedral with ligand environments consistent with the spectroscopic data. In all the structures the phosphine ligands are bent towards the fluoride ligands and show intramolecular H ... F interactions.

Full text of DOI:10.1039/a702142i

View Article Online / Journal Homepage / Table of Contents for this issue
Air-stable ruthenium(II) and osmium(II) fluoride complexes. Crystal
structures of [OC-6-13][MF2(CO)2(PR3)2] [M ؍ Ru, PR3 ؍ PEtPh2;
M ؍ Os, PR3 ؍ PPh3 or P(C6H11)3]
Karl S. Coleman, John Fawcett, John H. Holloway, Eric G. Hope* and David R. Russell
Department of Chemistry, University of Leicester, Leicester, UK LE1 7RH
The reaction of Lewis bases L with [{MF2(CO)3}4] (M = Ru or Os) in organic solvents provided a clean,
high-yield, route to a series of air- and moisture-stable ruthenium() and osmium() fluoride co-ordination
compounds of general formulae [MF2(CO)2L2]. Characterisation by elemental analysis, FAB mass spectrometry,
NMR and IR spectroscopy indicated a cis,cis,trans ligand arrangement. The crystal structures of [OC-6-13]-
[MF2(CO)2(PR3)2] [M = Ru, PR3 = PEtPh2; M = Os, PR3 = PPh3 or P(C6H11)3] have been determined by X-ray
crystallography. The geometry about the central metal atoms for all three structures is distorted pseudo-
octahedral with ligand environments consistent with the spectroscopic data. In all the structures the phosphine
ligands are bent towards the fluoride ligands and show intramolecular H ؒ ؒ ؒ F interactions.
Recently, there has been renewed interest in fluoride as a
ligand in low-oxidation-state transition-metal co-ordination
chemistry.1–3 There have been only three previous reports of
osmium() fluoride co-ordination compounds. In 1975,
Heymore and Ibers4 reported the first derivative in this class,
thetic procedure. A weighed amount of [{MF2(CO)3}4] (M =
Ru or Os) (ca. 0.10 g) was loaded into a Schlenk flask in a dry-
box along with, for the solid reagents, a slight excess of the
ligand (8 molar equivalents). After connecting the reaction
vessel to a vacuum line, freshly distilled dichloromethane
(M = Os) or acetone (M = Ru) (ca. 20 cm3) was transferred on-
to the reagents. Reaction ensued immediately with vigorous gas
evolution. The reaction mixture was then degassed and stirred
under dinitrogen for 3 h, to ensure complete reaction, affording
a yellow solution. The solvent was removed in vacuo and the
pale yellow/white solid recrystallised from dichloromethane
(Os) or benzene (Ru) and light petroleum (b.p. 40–60 ЊC) to give
the products in ca. 90% yields.
[OsF(CO) (N᎐NPh)(PPh ) ], during a broad investigation of
᎐
2
3 2
osmium aryldiazo complexes. More recently, we have described
the application of xenon difluoride, as an oxidative source of
fluorine, in the synthesis of [{OsF2(CO)3}4]5 and [OsF(CO)-
(COF )(PPh3)2] and [OsF2(CO)2(PPh3)2].6 There have been
more claims for ruthenium() fluoride co-ordination com-
pounds.7 However, for a number of these the reported charac-
terisation data are limited. In addition to our reports of
[{RuF2(CO)3}4]8–10 and [RuF(CO)(COF )(PPh3)2] and [RuF2-
(CO)2(PPh3)2],6 substantiated ruthenium() fluoride complexes
include [RuFCl2(NO)(bipy)] (bipy = 2,2Ј-bipyridine),2 the five-
co-ordinate hydridofluoride complex trans-[RuF(H)(CO)-
(PBut2Me)2] (and the products of the reaction of this complex
with a variety of ligands),11 and the cationic species [RuF(CO)-
(dppe)2]ϩ (dppe = Ph2PCH2CH2PPh2)12 and [RuF(CO)2(OH2)-
(PPh3)2]ϩ.13 These complexes have been prepared by diverse syn-
thetic routes, several of which were not designed to produce
low-oxidation-state fluorides. Here, we outline a general route
to this class of co-ordination compound by the reaction of
[{MF2(CO)3}4] (M = Ru or Os) with a range of Lewis bases.
In cases where the ligands are liquid the same procedures
were followed except that the ligands were introduced directly
into the reaction vessel after addition of the solvent.
Satisfactory elemental analyses were obtained for represen-
tative products: [RuF2(CO)2(PPh3)2] (Found: C, 63.09; H, 4.07.
C38H30F2O2P2Ru requires C, 63.42; H, 4.20); [RuF2(CO)2-
(PEtPh2)2] (Found: C, 57.90; H, 4.76. C30H30F2O2P2Ru requires
C, 57.78; H, 4.85%); [RuF2(CO)2{P(p-FC6H4)3}2] (Found: C,
54.84; H, 2.81. C38H24F8O2P2Ru requires C, 55.15; H, 2.92);
[RuF2(CO)2(AsPh3)2] (Found: C, 55.92; H, 3.72. C38H30As2-
F2O2Ru requires C, 56.52; H, 3.74); [OsF2(CO)2(PPh3)2]
(Found: C, 56.36; H, 3.69. C38H30F2O2OsP2 requires C, 56.43;
H, 3.74); [OsF2(CO)2(PMe3)2] (Found: C, 22.07; H, 4.19.
C8H18F2O2OsP2 requires C, 22.02; H, 4.16); [OsF2(CO)2-
{P(C6H11)3}2] (Found: C, 54.14; H, 7.93. C38H66F2O2OsP2
requires C, 54.01; H, 7.87%).
Experimental
Proton, 19F and 31P NMR spectra were recorded in CD2Cl2 (Os)
and [2H6]acetone (Ru) on a Bruker AM 300 spectrometer at
300.14, 282.36 and 121.50 MHz, referenced externally to SiMe4,
CFCl3 and 85% H3PO4, respectively. Infrared spectra were
recorded on Nujol mulls between KBr plates on a Digilab
FTS40 spectrometer. Elemental analyses were performed by
Butterworth Laboratories Ltd. and FAB mass spectra were
recorded on a Kratos Concept 1H mass spectrometer.
Crystallography
Crystals of [OsF2(CO)2(PPh3)2], [OsF2(CO)2{P(C6H11)3}2] and
[RuF2(CO)2(PEtPh2)2] suitable for diffraction were grown from
dichloromethane (M = Os) or acetone (M = Ru) by slow evap-
oration of the solvent. The crystal data and experimental
parameters are given in Table 4. Crystal stability was moni-
tored by the observation of the intensities of three standard
reflections and for none of the structures was there any signifi-
cant loss of intensity. For each data set a semiempirical
absorption correction was applied (based on ψ scans) and the
data were corrected for Lorentz and polarisation effects. All
structures were solved by Patterson methods using SHELXTL
PC 14 and refined by full-matrix least squares on F 2 using the
program package SHELXL 93.15 All non-hydrogen atoms were
The complexes [{MF2(CO)3}4] (M = Ru 9 or Os5) were
prepared as described previously and stored in a dry-box.
The ligands were commercial samples and used as supplied.
Dichloromethane was dried by refluxing over calcium hydride,
and acetone was dried over calcium sulfate.
Preparations
All of the complexes were prepared by the same general syn-
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562
3557

View Article Online
Table 1 Mass spectral, IR and NMR spectral data for [OC-6-13][OsF2(CO)2L2]
L
m/za
ν (CO)b/cmϪ1
NMR c
PPh3
791 [M Ϫ F]ϩ
2017, 1937
1H: 7.5 (m)
763 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ303.3 [t, 2J(PF ) 30]
31P: 1.0 (t)
PEtPh2
PMe3
695 [M Ϫ F]ϩ
2031, 1950
2024, 1939
2005, 1925
2029, 1959
1H: 1.1 (3 H, m), 2.0 (2 H, m), 7.3 (10 H, m)
19F: Ϫ310.3 [t, 2J(PF ) 33]
31P: 4.4 (t)
667 [M Ϫ F Ϫ CO]ϩ
419 [M Ϫ F]ϩ
1H: 1.6 [vt, nJ(PH) 8]
19F: Ϫ315.2 [t, 2J(PF ) 38]
31P: Ϫ14.8 (t)
391 [M Ϫ F Ϫ CO]ϩ
P(C6H11
)
827 [M Ϫ F]ϩ
1H: 2.1 (m)
3
799 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ309.6 [t, 2J(PF ) 29]
31P: 15.5 (t)
PPh2(C6F5)
971 [M Ϫ F]ϩ
1H: 7.6 (m)
943 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ300.5 [2 F, t, 2J(PF ) 33, FOs], Ϫ160.2 [4 F, Fm, m], Ϫ147.5
(2 F, Fp, m), Ϫ123.9 (4 F, Fo, m)
31P: 2.8 (t)
P(p-MeC6H4)3
P(p-FC6H4)3
PEt3
827 [M Ϫ 2F Ϫ CO]ϩ
2021, 1942
2035, 1962
2034, 1963
2026, 1941
2043, 1945
2023, 1943
1H: 2.4 (3 H, s), 7.4 (4 H, m)
19F: Ϫ302.7 [t, 2J(PF ) 32]
31P: Ϫ3.0 (t)
899 [M Ϫ F]ϩ
1H: 7.1 (m), 7.2 (m), 7.8 (m)
19F: Ϫ308.8 [2 F, t, 2J(PF ) 32, FOs], Ϫ108.8 (6 F, s, Fp)d
31P: Ϫ4.0 (t)
871 [M Ϫ F Ϫ CO]ϩ
503 [M Ϫ F]ϩ
1H: 1.3 (3 H, m), 2.0 (2 H, m)
19F: Ϫ317.4 [t, 2J(PF ) 33]
31P: 11.1 (t)
475 [M Ϫ F Ϫ CO]ϩ
PMePh2
667 [M Ϫ F]ϩ
1H: 2.0 (3 H, m), 7.3 (10 H, m)
19F: Ϫ310.6 [t, 2J(PF ) 35]
31P: Ϫ1.8 (t)
639 [M Ϫ F Ϫ CO]ϩ
PMe2Ph
543 [M Ϫ F]ϩ
1H: 1.7 (6 H, m), 7.3 (5 H, m)
19F: Ϫ312.6 [t, 2J(PF ) 37]
31P: Ϫ7.6 (t)
515 [M Ϫ F Ϫ CO]ϩ
PEt2Ph
599 [M Ϫ F]ϩ
1H: 1.0 (6 H, m), 2.1 (4 H, m), 7.3 (5 H, m)
19F: Ϫ313.8 [t, 2J(PF ) 34]
31P: 9.4 (t)
571 [M Ϫ F Ϫ CO]ϩ
C5H5N
AsPh3
425 [M Ϫ F]ϩ
2010, 1943
2050, 2007
1H: 7.7 (m)
19F: Ϫ286.8 (s)
851 [M Ϫ F Ϫ CO]ϩ
1H: 7.5 (m)
19F: Ϫ340.6 (s)
a
Fast-atom bombardment with m-nitrobenzyl alcohol matrix. b Recorded as Nujol mulls; ±2 cmϪ1 c Recorded in CD2Cl2. Data given as: chemical
.
shift (δ) (relative intensity, multiplicity, J in Hz, assignment); s = singlet, d = doublet, t = triplet, vt = virtual triplet, m = multiplet. d Only observed
on broad-band proton decoupling.
refined as anisotropic with the exception of the solvent atoms
in the [OsF2(CO)2(PPh3)2] structure. Hydrogen atoms were
included in calculated positions (C᎐H 0.96 Å) with positional
parameters riding on the attached atom and with a fixed iso-
tropic thermal parameter (Uiso = 0.08 Å2). The final Fourier-
difference map of [OsF2(CO)2{P(C6H11)3}2] had ϩ1.91 and
Ϫ2.09 e ÅϪ3 peaks approximately 1 Å from the osmium atom;
in all other respects the final Fourier-difference maps were
satisfactory.
resonances in excellent agreement with those of our previously
characterised [OC-6-13][MF2(CO)2(PPh3)2] (M = Ru or Os).6
For the other phosphine-containing products the NMR spectra
exhibit similar mutually-coupled triplet resonances with
2
comparable JPF coupling constants and 19F NMR chemical
shifts, indicative of F trans to CO, which confirm that this
reaction offers a general route to [OC-6-13][MF2(CO)2L2]
(M = Ru or Os; L = two-electron donor ligand) co-ordination
compounds.
CCDC reference number 186/579.
For the range of phosphine ligands, δ(19F ) is virtually con-
stant while δ(FRu) occurs to lower frequency than δ(FOs) as
observed throughout all of our studies of ruthenium and
osmium carbonyl fluorides. When the 19F NMR data for cis-
[MF2(CO)4] (M = Ru, δ Ϫ349.0; M = Os, δ Ϫ342.5) are
included, a general shift to higher frequency for δ(Ftrans᎐CO)
with increasing σ-donor strength of the axial ligand pyrid-
ine (py) > phosphine > CO > AsPh3 is identified. Further work
is underway to investigate whether this trend holds for all types
of donor ligand. However, this observation is opposite to that
previously reported for the co-ordination of CO or pyridine to
five-co-ordinate [RuH(F )(CO)(PBut2Me)2], namely [RuH(F )-
(CO)2(PBut2Me)2] δ(F ) Ϫ202 and [RuH(F )(CO)(py)(PBut2-
Me)2] δ(F ) Ϫ491.11 We note that the chemical shift reported for
this pyridine adduct is extremely low and, on the basis of our
work, is not typical for δ(F ) for fluoride trans to carbonyl, but is
more typical of a bridging fluoride ligand or of fluoride trans
to halide. This discrepancy between the observations from our
work and that previously reported 11 indicates that more
detailed study is necessary in this area.
Results and Discussion
The complexes [{MF2(CO)3}4] (M = Ru or Os) are highly mois-
ture- and oxygen-sensitive and are insoluble in the common
organic solvents. However, after addition of any one of a series
of Lewis bases in dichloromethane (M = Os) or acetone
(M = Ru) in an inert atmosphere, carbon monoxide gas is
evolved and the metal complexes dissolve completely to give
yellow solutions. Halogenated solvents are incompatible with
the products when M = Ru since they appear to undergo
halogen-exchange reactions; similar reactions have been
observed for iridium() fluoride complexes in dichloro-
methane.16 Removal of the solvent in vacuum yields the prod-
ucts as air-stable off-white or pale yellow solids. The NMR
spectroscopic studies in solution (Tables 1 and 2), particularly
for the products containing phosphine ligands, give a clear
indication of the chemical composition. When L = PPh3 the
19F and 31P NMR spectra show mutually-coupled triplet
3558
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562

View Article Online
Table 2 Mass spectral, IR and NMR spectral data for [OC-6-13][RuF2(CO)2L2]
L
m/za
ν(CO)b/cmϪ1
NMR c
PPh3
701 [M Ϫ F]ϩ
2045, 1973
1H: 7.6 (m)
673 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ324.3 [t, 2J(PF ) 20]
31P: 21.6 (t)
PEtPh2
PMe3
577 [M Ϫ F Ϫ CO]ϩ
301 [M Ϫ F Ϫ CO]ϩ
737 [M Ϫ F]ϩ
2046, 1961
2047, 1974
2017, 1936
2055, 1986
1H: 1.1 (3 H, m), 2.3 (2 H, m), 7.4 (10 H, m)
19F: Ϫ327.1 [t, 2J(PF ) 22]
31P: 24.8 (t)
1H: 1.6 [vt, nJ(PH) 7]
19F: Ϫ328.7 [t, 2J(PF ) 28]
31P: 3.3 (t)
P(C6H11
)
1H: 1.8 (m)
3
19F: Ϫ324.3 [t, 2J(PF ) 20]
31P: 36.6 (t)
PPh2(C6F5)
881 [M Ϫ F]ϩ
1H: 7.5 (m)
853 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ321.2 [2 F, t, 2J(PF ) 25, FRu], Ϫ162.0 (4 F, Fm, m),
Ϫ149.7 (2 F, Fp, m), Ϫ123.9 (4 F, Fo, m)
31P: 21.7 (t)
P(p-MeC6H4)3
P(p-FC6H4)3
PEt3
757 [M Ϫ F Ϫ CO]ϩ
2045, 1975
2047, 1974
2036, 1963
2046, 1977
2043, 1964
2047, 1978
1H: 2.1 (3 H, s), 7.2 (4 H, m)
19F: Ϫ327.5 [t, 2J(PF ) 22]
31P: 15.7 (t)
809 [M Ϫ F]ϩ
1H: 7.5 (m), 8.2 (m)
781 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ333.1 [2 F, t, 2J(PF ) 23, FRu], Ϫ108.9 (6 F, s, Fp)d
31P: 14.9 (t)
413 [M Ϫ F]ϩ
1H: 1.2 (3 H, m), 2.1 (2 H, m)
19F: Ϫ330.2 [t, 2J(PF ) 23]
31P: 28.8 (t)
385 [M Ϫ F Ϫ CO]ϩ
PMePh2
549 [M Ϫ F Ϫ CO]ϩ
1H: 1.9 (3 H, m), 7.5 (10 H, m)
19F: Ϫ324.5 [t, 2J(PF ) 25]
31P: 16.9 (t)
PMe2Ph
453 [M Ϫ F]ϩ
1H: 1.8 (6 H, m), 7.5 (5 H, m)
19F: Ϫ325.1 [t, 2J(PF ) 25]
31P: 7.8 (t)
425 [M Ϫ F Ϫ CO]ϩ
PEt2Ph
481 [M Ϫ F Ϫ CO]ϩ
1H: 1.1 (6 H, m), 2.0 (4 H, m), 7.6 (5 H, m)
19F: Ϫ327.0 [t, 2J(PF ) 21]
31P: 24.3 (t)
C5H5N
AsPh3
335 [M Ϫ F]ϩ
2042, 1959
2031, 1958
1H: 7.8 (m)
19F: Ϫ269.7
789 [M Ϫ F]ϩ
1H: 7.5 (m)
761 [M Ϫ F Ϫ CO]ϩ
19F: Ϫ349.0
a
Fast-atom bombardment with m-nitrobenzyl alcohol matrix. b Recorded as Nujol mulls; ±2 cmϪ1 c Recorded in [2H6]acetone. d Only observed on
.
broad-band proton decoupling.
17
The co-ordination chemical shift ∆31P(δcomplex Ϫ δfree
)
Table 3 Comparison of the CO stretching frequencies for the
complexes cis,cis,trans-[MX2(CO)2(PPh3)2] as a function of X
ligand
2
and the JPF coupling constants show a decrease and increase,
respectively, with increasing cone angle of the phosphine lig-
and. Similar trends have been identified for [OC-6-33]-
[RuCl2(CO)2L2]18 and [OC-6-13][IrF(COF )(CO)2L2][BF4],19
although the origin of this influence is not clear. A better indi-
cation of ligand effects arises from the observed variation in
δ(31P) in a series of complexes [MX2(CO)2L2] where only the
anionic ligand X is varied for constant L. The first derivatives in
this class were reported in the early 1960s and so 31P NMR data
are not available for all ligand combinations. From the limited
data available it appears that the 31P chemical shifts decrease in
the order F > SCN > Cl > Br > I in line with the nephelauxetic
effect [i.e. L = PPh3, M = Ru; X = SCN δ(P) = 20.9, X = Cl
δ(P) = 17.1, X = Br δ(P) = 13.3, X = I δ(P) = 7.8].20
As expected, these derivatives show two carbonyl stretching
vibrations in their IR spectra, which are insensitive to the
nature of L (Tables 1 and 2). Comparison of these data with
those for the analogous chloride, bromide and iodide complexes
(Table 3), indicates that ν(CO) is lower for fluoride than chlor-
ide ≈ bromide ≈ iodide. This trend is contrary to that expected
from electronegativity arguments. However, theoretical studies
on the 18-electron [RuF(H)(CO)(PBut2Me)2L] (L = py or CO)11
indicate that the CO π* orbitals can interact to stabilise Ru᎐X
π* orbitals, thus allowing some degree of net Ru᎐X π bonding.
Hence, these data offer further experimental evidence to sup-
port the view that fluoride can behave as a significant π-electron
donor to low-valent transition-metal derivatives when π-acidic
ligands are present. Similar trends in CO and NO stretching
frequencies have been described for trans-[MX(CO)(PPh3)2]
X
M = Os
M = Ru
H
F
Cl
Br
I
2020, 1990a
2017, 1937b
2041, 1970c
2042, 1970c
2040, 1975c
2011, 1974a
2045, 1973b
2061, 1998d
2058, 1994d
2050, 1990d
Recorded in heptane.21 b Recorded in Nujol, this work. c Recorded in
a
C2Cl4.22 d Recorded in Nujol.19
(M = Rh or Ir),23 [ReX(NO)(PR3)(η5-C5H5)],24 [ReCl2F(NO)-
(bipy)],3 [RuX(H)(CO)(py)(PBut2Me)2] and [RuX(H)(CO)-
(PBut2Me)2]11 (X = halide).
There are five possible isomers for [MX2(CO)2L2] complexes.
For the heavier halides (X = Cl, Br or I), four isomers (M = Os)
and all five isomers (M = Ru) have been prepared, although the
cis,cis,trans and trans,cis,cis isomers have been shown to be
more stable than the other isomers and have been described
more frequently.25 The cis,cis,trans isomer is usually formed at
high temperatures and is recognised as the thermodynamic
product; the trans,cis,cis isomer, the kinetic product, is usually
found at lower temperatures. When X = F, we have only
observed the cis,cis,trans isomer, even when the reaction mix-
ture is held at low temperatures, indicating the strong thermo-
dynamic driving force for this configuration and the strong
preference for the fluoride trans to carbonyl arrangement. We
have noted a similar thermodynamic preference for a fluoride
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562
3559

View Article Online
Table 4 X-Ray crystal data collection, solution and refinement details for [OC-6-13][RuF2(CO)2(PEtPh2)2], [OC-6-13][OsF2(CO)2{P(C6H11)3}2]ؒ
CH2Cl2 and [OC-6-13][OsF2(CO)2(PPh3)2]ؒCH2Cl2*
[OsF2(CO)2(PPh3)2]
[OsF2(CO)2{P(C6H11)3}2]
[RuF2(CO)2(PEtPh2)2]
Formula
M
C39H32Cl2F2O2OsP2
893.69
C39H36Cl2F2O2OsP2
929.97
C30H30F2O2P2Ru
623.55
T/K
293
190
193
Crystal system
Space group
Monoclinic
C2/c
Triclinic
P1
Monoclinic
P21/n
¯
a/Å
b/Å
c/Å
α/Њ
17.197(2)
10.791(2)
20.034(3)
10.732(2)
12.519(2)
17.228(4)
81.14(1)
9.751(1)
13.022(1)
22.415(2)
β/Њ
102.94(1)
76.12(2)
100.93(1)
γ/Њ
71.13(2)
2118.9(7)
22, 5.2–12.5
U/Å3
3623.4(10)
53, 4.2–12.5
2794.6(4)
29, 3.8–12.5
Cell measurement reflections used,
θ range/Њ
Z
4
2
4
Dc/Mg mϪ3
1.638
3.799
1.458
3.250
1.482
0.714
µ/mmϪ1
Maximum, minimum transmission
F(000)
0.94, 0.78
1760
0.86, 0.67
952
0.80, 0.78
1272
Crystal size/mm
Index ranges
0.38 × 0.18 × 0.11
Ϫ1 р h р 20, Ϫ1 р k р 12,
Ϫ23 р l р 23
2.5–25
0.60 × 0.56 × 0.55
Ϫ1 р h р 12, Ϫ14 р k р 14,
Ϫ20 р l р 20
2.5–25
0.70 × 0.40 × 0.28
Ϫ1 р h р 12, Ϫ1 р k р 16,
Ϫ28 р l р 28
2.5–27
θ Range/Њ
Reflections collected
4071
8688
7820
Independent reflections (Rint
Data, restraints, parameters
Goodness of fit on F 2
Final R1, wR2 indices
(all data)
)
3184 (0.0294)
3184, 0, 210
0.963
0.0485, 0.1170
0.0682, 0.1236
0.924, Ϫ1.03
7406 (0.0301)
7405, 0, 442
1.045
0.0447, 0.1083
0.0576, 0.1165
1.910, Ϫ2.093
(ca. 1 Å from Os)
6100 (0.0245)
6100, 0, 334
1.041
0.0359, 0.0840
0.0513, 0.0921
0.536, 0.391
Largest difference peak and hole/e ÅϪ3
¹
2
* Details in common: Siemens P4 diffractometer, λ(Mo-Kα) = 0.7107 Å, ω-scan type; R1 = Σ Fo| Ϫ |Fc /Σ|Fo|; wR2 = [Σw(Fo2 Ϫ Fc )2/Σw(Fo2)2]².
¹
2
Goodness of fit, S = [Σw(Fo2 Ϫ Fc )2/(n Ϫ p)]², where n = number of reflections and p is the total number of parameters refined.
Fig. 1 Molecular structure of [OC-6-13][OsF2(CO)2(PPh3)2]ؒCH2Cl2;
displacement ellipsoids are shown at the 30% level
trans to carbonyl arrangement in the isomerisation of mer- and
fac-[IrF3(CO)3] even at very low temperatures.1
The complexes [OC-6-13][MF2(CO)2L2] [M = Os, L = PPh3
or P(C6H11)3; M = Ru, L = PPh2Et] have been further character-
ised by X-ray crystallography; these structure determinations
Fig. 2 Molecular structure of [OC-6-13][OsF2(CO)2{P(C6H11)3}2]ؒ
include the first examples of crystallographic analyses of
osmium() fluoride complexes. The structures are shown in
Figs. 1–3 and selected bond lengths and angles, together with
data for the isostructural [OC-6-13][RuF2(CO)2(PPh3)2],6 are
given in Table 5. The complexes are pseudo-octahedral with the
two phosphine ligands trans to each other and the fluoride
ligands trans to the carbonyl groups, as indicated by NMR
spectroscopy, for these same complexes in solution. The metal–
CH2Cl2; displacement ellipsoids are shown at the 30% level. The
hydrogen atoms other than those involved in hydrogen bonding are
omitted for clarity
fluorine bond lengths are very similar to each other and to
those of the only other crystallographically characterised car-
bonyl fluoride complexes of d6-transition metals: [ReF(CO)3-
(Me2NCH2CH2NMe2)], Re᎐F 2.039(4) Å,26 [{RuF2(CO)3}4],
3560
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562

View Article Online
Table 5 Selected bond lengths (Å) and angles (Њ) with estimated standard deviations in parentheses for [OC-6-13][RuF2(CO)2(PPh3)2]ؒCD2Cl2,6
[OC-6-13][RuF2(CO)2(PEtPh2)2], [OC-6-13][OsF2(CO)2{P(C6H11)3}2]ؒCH2Cl2 and [OC-6-13][OsF2(CO)2(PPh3)2]ؒCH2Cl2
[RuF2(CO)2(PPh3)2]ؒCD2Cl2
[RuF2(CO)2(PEtPh2)2]
[OsF2(CO)2{P(C6H11)3}2]ؒCH2Cl2
[OsF2(CO)2(PPh3)2]ؒCH2Cl2
M᎐F
M᎐P
M᎐C
C᎐O
2.011(4)
2.017(2)
2.028(2)
2.3921(7)
2.3872(7)
1.855(3)
1.853(3)
1.146(4)
1.132(4)
2.023(4)
2.022(4)
2.438(2)
2.423(2)
1.841(8)
1.854(7)
1.158(9)
1.154(8)
2.023(5)
2.406(1)
1.841(7)
1.135(9)
2.418(2)
1.832(9)
1.178(9)
P᎐M᎐P
F᎐M᎐F
C᎐M᎐C
M᎐C᎐O
178.2(1)
84.4(2)
92.2(4)
178.7(8)
171.82(2)
86.40(7)
91.9(2)
166.41(5)
83.5(2)
86.6(3)
177.59(10)
81.3(3)
90.5(5)
179.3(3)
177.5(6)
178.8(7)
Fig. 4 Extended structure of [OC-6-13][RuF2(CO)2(PEtPh2)2] show-
ing intermolecular interactions; displacement ellipsoids are shown at
the 30% level
number of short H ؒ ؒ ؒ F distances are observed [H(26B) ؒ ؒ ؒ
F(1) 2.253, H(32B) ؒ ؒ ؒ F(1) 2.238, H(26A) ؒ ؒ ؒ F(1A) 2.252 and
H(32A) ؒ ؒ ؒ F(1A) 2.238 Å], all of which are shorter than the
sum of the van der Waals radii of hydrogen and fluorine
[rvdw(H) = 1.20, rvdw(F ) = 1.47 Å].30 In the absence of stronger
interactions, it is now recognised that weak F ؒ ؒ ؒ H᎐C inter-
actions, like these, are important in aligning molecules.31
Indeed, an early example of intramolecular C᎐F bond acti-
vation was believed to occur via HF elimination arising from
incipient H ؒ ؒ ؒ F hydrogen bonding,32 but the number of
examples of F ؒ ؒ ؒ H᎐C interactions involving metal-bound
fluoride ligands is limited.33 In [OC-6-13][OsF2(CO)2-
{P(C6H11)3}2], the P(C6H11)3 ligands are bent towards the fluor-
ide ligands [P᎐Os᎐P 166.41(5)Њ] resulting in more non-bonding,
short intramolecular H ؒ ؒ ؒ F distances [H(21A) ؒ ؒ ؒ F(1) 2.470,
H(26B) ؒ ؒ ؒ F(1) 2.373, H(42A) ؒ ؒ ؒ F(1) 2.279, H(46B) ؒ ؒ ؒ F(1)
2.304, H(26B) ؒ ؒ ؒ F(2) 2.454 and H(32B) ؒ ؒ ؒ F(2) 2.356 Å].
Similarly, in [OC-6-13][RuF2(CO)2(PEtPh2)2], the phosphines
are bent towards the fluorine atoms [P᎐Ru᎐P 171.82(2)Њ] with
short non-bonding, intramolecular H ؒ ؒ ؒ F interactions
[H(6C) ؒ ؒ ؒ F(1) 2.476, H(32A) ؒ ؒ ؒ F(2) 2.298 and H(16A) ؒ ؒ ؒ
F(2) 2.421 Å]. The eclipsed ligand orientation results in the
ethyl groups lying coplanar with the Ru᎐F(1) axis which may
account for the variation in the Ru᎐F bond lengths in this
complex. For all three complexes the intramolecular H ؒ ؒ ؒ F
interactions do not significantly influence the angles at phos-
phorus. The ruthenium complex is unique among these struc-
tures since, in addition to these short intramolecular inter-
actions, an extended view of the structure indicates short
intermolecular interactions between the fluoride ligands and
hydrogen atoms on the phenyl rings of two adjacent molecules
in the unit cell [H(22AЈ) ؒ ؒ ؒ F(1) 2.235 and H(43AЉ) ؒ ؒ ؒ F(2)
Fig. 3 Molecular structure of [OC-6-13][RuF2(CO)2(PEtPh2)2]; dis-
placement ellipsoids are shown at the 30% level
Ru᎐Fterminal 1.99(7), Ru᎐Fbridging 2.04(7) Å,8 [IrF(COF )(CO)2-
(PEt3)2][BF4], Ir᎐F 1.998(3) Å,27 [IrF(Cl)(NSF2)(CO)(PPh3)2],
Ir᎐F 2.089(4) Å.28 In [OC-6-13][RuF2(CO)2(PEtPh2)2] only
there is a discernible difference between the two M᎐F bond
lengths. The metal–phosphorus bond lengths are slightly longer
than those in other neutral d6-transition-metal complexes,29 but
are not unreasonable when compared to those in the other d6
metal fluoride complexes.26,28 The phosphine ligands with the
smaller cone angle have the shorter M᎐P distance [2.3896(7) Å
(mean) for PEtPh2, 2.413(2) Å (mean) for PPh3 and 2.430(2) Å
(mean) for P(C6H11)3] which may be linked to the variation
in ∆(31P). The metal–carbon distances are very similar to,
although slightly shorter than, those observed for other
osmium() and ruthenium() compounds (1.873–1.880 Å).29
There is a similar variation in the C᎐O bond length which
correlates with the variation in ν(CO).
It is noteworthy that there is a considerable difference in the
P᎐M᎐P angles [177.59(10)–166.41(5)Њ] as the phosphine ligand
is changed. The orientation of the substituents on these ligands
also varies; for [OC-6-13][MF2(CO)2(PPh3)2] (M = Ru or Os)
the aryl rings are staggered whilst for [OC-6-13][OsF2-
(CO)2{P(C6H11)3}2] and [OC-6-13][RuF2(CO)2(PEtPh2)2] the
alkyl groups are eclipsed. All of the complexes contain short
intramolecular interactions between hydrogen atoms on the
ligands and the fluorides. For [OC-6-13][OsF2(CO)2(PPh3)2] a
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562
3561

View Article Online
9 K. S. Coleman, J. H. Holloway and E. G. Hope, J. Chem. Soc.,
Dalton Trans., 1997, 1713.
2.378 Å]. These hydrogen-bonding interactions also appear to
influence the C᎐O bond lengths. For [OC-6-13][RuF2(CO)2-
(PEtPh2)2], in particular, C(1)᎐O(1) [i.e. trans to F(1)] is shorter
than C(2)᎐O(2) which may be rationalised by a reduction of the
F→Ru π bonding which offers further support to the conclu-
sion that fluoride can act as a significant π-electron donor in
these systems.
One molecule of dichloromethane cocrystallises with one
molecule of the metal complexes in the crystal structures of
[OC-6-13][OsF2(CO)2(PPh3)2] and [OC-6-13][OsF2(CO)2{P(C6-
H11)3}2]. In both cases the solvent molecule is very close to the
equatorial plane containing the metal, carbonyl and fluoride
ligands and is held by further, short intramolecular H ؒ ؒ ؒ F
interactions.
10 A. J. Hewitt, J. H. Holloway, R. D. Peacock, J. B. Raynor and
I. L. Wilson, J. Chem. Soc., Dalton Trans., 1976, 579.
11 K. G. Caulton, O. Eisenstein, J. T. Poulton, M. P. Sigalas and
W. E. Streib, Inorg. Chem., 1994, 33, 1476.
12 D. J. Cole-Hamilton, N. G. Gooden, A. C. Gregory and G. Smith,
Polyhedron, 1982, 1, 97.
13 W. Beck, R. Krömer, E. Lippmann, U. Nagel, K. Noistering and
M. Steimann, Chem. Ber., 1993, 126, 927.
14 G. M. Sheldrick, SHELXTL PC, Release 4.2, Siemens Analytical
X-Ray Instruments, Madison, WI, 1991.
15 G. M. Sheldrick, SHELXL 93, Program for Crystal Structure
Refinement, University of Göttingen, 1993.
16 R. W. Cockman, E. A. V. Ebsworth, J. H. Holloway, H. Murdoch,
N. Robertson and P. G. Watson, ACS Symp. Ser., 1994, 555, 326.
17 B. E. Mann, J. Chem. Soc., Perkin Trans. 2, 1972, 30.
18 D. F. Gill, B. E. Mann and B. L. Shaw, J. Chem. Soc., Dalton Trans.,
1973, 311.
19 E. A. V. Ebsworth, N. Robertson and L. Y. Yellowlees, J. Chem. Soc.,
Dalton Trans., 1993, 1031.
20 H. B. Kuhnhen, J. Organomet. Chem., 1976, 105, 357.
21 F. L’Eplatteneir and F. Calderazzo, Inorg. Chem., 1968, 7, 1920.
22 L. A. W. Hales and R. J. Irving, Spectrochim. Acta, Part A, 1967, 23,
2981.
23 L. Vaska and J. Peone, Chem. Commun., 1971, 418.
24 W. E. Buhro, J. Fernandes, J. A. Gladysz and J. H. Merrifield, Inorg.
Chem., 1984, 23, 4022.
25 N. C. Thomas, Coord. Chem. Rev., 1986, 70, 121; 1989, 93, 225;
B. R. James and L. D. Markham, Inorg. Nucl. Chem. Lett., 1971, 7,
373.
26 E. Horn and M. R. Snow, Aust. J. Chem., 1984, 37, 35.
27 A. J. Blake, R. W. Cockman, E. A. V. Ebsworth and J. H. Holloway,
J. Chem. Soc., Chem. Commun., 1988, 529.
Conclusion
The reaction of [{MF2(CO)3}4] (M = Ru or Os) with Lewis
bases represents a convenient route to some air- and moisture-
stable ruthenium() and osmium() fluoride co-ordination
complexes of general formulae [MF2(CO)2L2], which preferen-
tially adopt cis,cis,trans ligand arrangements.
Acknowledgements
We would like to thank the Royal Society (E. G. H.) and the
EPSRC (K. S. C., E. G. H.) for financial support, a referee for
useful comments and Dr. S. A. Brewer for preliminary work.
28 P. G. Watson, E. Lork and R. Mews, J. Chem. Soc., Chem.
Commun., 1994, 1069.
References
1 S. A. Brewer, A. K. Brisdon, J. H. Holloway, E. G. Hope, L. A. Peck
and P. G. Watson, J. Chem. Soc., Dalton Trans., 1995, 2945.
2 R. G. Bergman, P. Burger and J. E. Veltheer, J. Am. Chem. Soc.,
1995, 117, 12 478.
3 M. Ahlgrén, M. Haukka and T. A. Pakkanen, J. Chem. Soc., Dalton
Trans., 1996, 1972.
29 F. H. Allen, L. Brammer, O. Kennard, A. G. Orpen, R. Taylor and
D. G. Watson, J. Chem. Soc., Dalton Trans., 1989, S1.
30 A. Bondi, J. Phys. Chem., 1964, 68, 441.
31 L. Shimoni and J. P. Glusker, Struct. Chem., 1994, 5, 383; L.
Shimoni, H. L. Carrell, J. P. Glusker and M. M. Coombs. J. Am.
Chem. Soc., 1994, 116, 8162.
4 B. L. Heymore and J. A. Ibers, Inorg. Chem., 1975, 14, 2784.
5 S. A. Brewer, J. H. Holloway and E. G. Hope, J. Chem. Soc., Dalton
Trans., 1994, 1067.
6 S. A. Brewer, K. S. Coleman, J. Fawcett, J. H. Holloway, E. G. Hope,
D. R. Russell and P. G. Watson, J. Chem. Soc., Dalton Trans., 1995,
1073.
32 J. A. K. Howard, S. A. R. Knox, N. J. Terrill and M. I. Yates,
J. Chem. Soc., Chem. Commun., 1989, 640.
33 See, for example, C. E. Osterberg, M. A. King, A. M. Arif and
T. G. Richmond, Angew. Chem., Int. Ed. Engl., 1990, 29, 888.
7 N. M. Doherty and N. W. Hoffman, Chem. Rev., 1991, 91, 553.
8 C. J. Marshall, R. D. Peacock, D. R. Russell and I. L. Wilson, Chem.
Commun., 1970, 1643.
Received 27th March 1997; Paper 7/02142I
3562
J. Chem. Soc., Dalton Trans., 1997, Pages 3557–3562