Synthesis and characterization of the trihalophosphine compounds of ruthenium [RuX2(η6-cymene)(PY3)] (X = Cl, Br, Y = F, Cl, Br) and the related PF2(NMe2) and P(NMe2)3 compounds; multinuclear NMR spectroscopy and the X-ray single crystal structures of [RuBr2(η6-cymene) (PF3)]...

Article abstract of DOI:10.1021/ic800611h

Full title: Synthesis and characterization of the trihalophosphine compounds of ruthenium [RuX₂(η⁶-cymene)(PY₃)] (X = Cl, Br, Y = F, Cl, Br) and the related PF₂(NMe₂) and P(NMe₂)₃ compounds; multinuclear NMR spectroscopy and the X-ray single crystal structures of [RuBr₂(η⁶-cymene) (PF₃)], [RuBr₂(η⁶-cymene)(PF ₂{NMe₂})]. Treatment of the dimers [RuX₂(η⁶-cymene)] ₂ with PF₃ in hot heptane produces the compounds [RuX ₂(η⁶-cymene)(PF₃)] (X = Cl, Br, I) in good yield. Difluoro(dimethylamino)phosphine and tris(dimethylamino)phosphine react similarly to produce the compounds [RuX₂(η⁶-cymene) (PF₂{NMe₂})] and [RuX₂(η⁶- cymene)(P{NMe₂}₃)]. Reaction of the dimers [RuX ₂(η⁶-cymene)]₂ with PCl₃ and PBr₃ proceeded with the production of mononuclear products which had undergone halogen exchange at ruthenium in some cases. ¹H, ¹³C, ³¹P, and ¹⁹F NMR spectra have been obtained where appropriate together with (¹H-¹H) correlation spectroscopy (COSY) and (¹³C-¹H)-HETCORR spectra of selected compounds. The variation of ¹J( ³¹P-¹⁹F) with the nature of the auxiliary ligand (X) in the PF₃ and PF₂(NMe₂) complexes has been examined both experimentally and computationally using a natural localized molecular orbital-natural bond order approach. The single crystal X-ray structure of [RuBr₂(η⁶-cymene)(PF₃)] has been determined at 223 K and those of [RuBr₂(η⁶- cymene)(PF₂{NMe₂})] and [RuI₂(η ⁶-cymene)(P{NMe₂}₃)] at 294 K.

Full text of DOI:10.1021/ic800611h

Inorg. Chem. 2008, 47, 9279-9292
Synthesis and Characterization of the Trihalophosphine Compounds of
Ruthenium [RuX2(η6-cymene)(PY3)] (X ) Cl, Br, Y ) F, Cl, Br) and the
Related PF2(NMe2) and P(NMe2)3 Compounds; Multinuclear NMR
Spectroscopy and the X-ray Single Crystal Structures of
[RuBr2(η6-cymene)(PF3)], [RuBr2(η6-cymene)(PF2{NMe2})], and
[RuI2(η6-cymene)(P{NMe2}3)]
Ahmed M. A. Boshaala,† Stephen J. Simpson,*,†,‡ Jochen Autschbach,*,§ and Shaohui Zheng§
Institute of Materials Research, UniVersity of Salford, Salford M5 4WT, U.K., School of
Biosciences, UniVersity of Exeter, 216B Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD,
U.K., and Department of Chemistry, 312 Natural Sciences Complex, State UniVersity of New York
at Buffalo, Buffalo, New York 14260-3000
Received April 4, 2008
6
6
Treatment of the dimers [RuX2(η -cymene)]2 with PF3 in hot heptane produces the compounds [RuX2(η -cymene)(PF3)]
(X ) Cl, Br, I) in good yield. Difluoro(dimethylamino)phosphine and tris(dimethylamino)phosphine react similarly to
6
6
produce the compounds [RuX2(η -cymene)(PF2{NMe2})] and [RuX2(η -cymene)(P{NMe2}3)]. Reaction of the dimers
[RuX2(η -cymene)]2 with PCl3 and PBr3 proceeded with the production of mononuclear products which had undergone
halogen exchange at ruthenium in some cases. H, 13C, 31P, and 19F NMR spectra have been obtained where
6
1
1
1
appropriate together with (1H- H) correlation spectroscopy (COSY) and (13C- H)-HETCORR spectra of selected
1
19
compounds. The variation of J(31P- F) with the nature of the auxiliary ligand (X) in the PF3 and PF2(NMe2)
complexes has been examined both experimentally and computationally using a natural localized molecular orbital-
6
natural bond order approach. The single crystal X-ray structure of [RuBr2(η -cymene)(PF3)] has been determined
6
6
at 223 K and those of [RuBr2(η -cymene)(PF2{NMe2})] and [RuI2(η -cymene)(P{NMe2}3)] at 294 K.
Introduction
π-acceptor properties to carbon monoxide, the respective
Tolman electronic parameters are 2111 cm-1 and 2128 cm-1,
the latter value being obtained from the Raman spectrum of
Ni(CO)4.7 Trifluorophosphine compounds are comparatively
less common; this could be due to the coordinated ligand
being an insensitive infrared probe and the very high
commercial cost of the gas compared to carbon monoxide.
The free ligand has a reputation for being much more toxic
than carbon monoxide, both are colorless and odorless but
whereas the symptoms of carbon monoxide poisoning are
pinkness of complexion, drowsiness, and eventual loss of
consciousness, the phosphine causes sharp chest pains,
nausea, and weakness on inhalation of small quantities.8-10
The preparative transition metal chemistry of trifluoro-
phosphine (PF3) blossomed in the period 1960-1985 with
the work of Clark,1 Kruck,2 and Nixon.3,4 The volatility of
many homoleptic derivatives has been used in mass transfer
applications, for example, the use of [Fe(PF3)5] to determine
isotope ratios in iron samples5 and deposition of platinum
films from [Pt(PF3)4].6 The PF3 ligand has very similar
* To whom correspondence should be addressed. E-mail: s.j.simpson@
exeter.ac.uk. (S.J.S.), jochena@buffalo.edu (J.A.).
†
University of Salford.
University of Exeter.
State University of New York at Buffalo.
‡
§
(1) Clark, R. J.; Busch, M. A. Acc. Chem. Res. 1973, 6, 246–252.
(2) Kruck, T. Angew. Chem., Int. Ed. Engl. 1967, 53–67.
(3) Nixon, J. F. EndeaVour 1973, 32, 19–24.
(4) Nixon, J. F. AdV. Inorg. Chem. 1985, 29, 41–141.
(5) Taylor, P. D. P.; Lehto, S.; Valkiers, S.; De Bievre, P.; Selgrad, O.;
Flegel, U.; Kruck, T. Anal. Chem. 1998, 70, 1033–1035.
(6) Wang, S.; Sun, Y. M.; Wang, Q.; White, J. M. J. Vac. Sci. Technol.
B. 2004, 22, 1803–1806.
(7) Stammreich, H.; Kawai, K.; Sala, O.; Krumholz, P. J. Chem. Phys.
1961, 35, 2168–2174.
(8) Booth, H. S.; Frary, S. G. J. Am. Chem. Soc. 1939, 61, 2934–2937.
10.1021/ic800611h CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 20, 2008 9279
Published on Web 09/23/2008

Boshaala et al.
Scheme 1
Both gases cause a pronounced rise in body temperature in
small doses, but there are no comparative human toxicity
data for the pair. Trifluorophosphine is known to form a
complex with hemoglobin which is rapidly hydrolyzed under
physiological and alkaline conditions.11 Our aim was to
generate PF3 as required and to investigate the NMR
spectroscopic properties of the ligand attached to a ruthenium
center.
The coordination chemistry of the other phosphorus
trihalides is more limited due partially to the poorer ligating
properties and more commonly to the extreme moisture
sensitivity of both the ligands and the metal compounds
prepared. Phosphorus trifluoride is only hydrolyzed slowly
in mildly acidic and neutral solutions. Schutzenberger12
obtained a stable complex of PCl3 with PtCl2 in the
nineteenth century, and in the early period of development
of the Dewar-Chatt-Duncanson bonding model, stable
nickel compounds of PCl3 and PBr3 were reported.13-15 This
work was later extended with the advent of multinuclear
NMR spectrometry.16 A number of Group 6 metal com-
pounds [M(CO)5(PX3)] have been prepared, structurally
characterized, and investigated theoretically; these include
PF3, PCl3, and PBr3 compounds.17,18 Earlier we prepared the
carbonyl compound [RuCl2(η6-cymene)(CO)],19 and the
stability of this compound containing a poor σ- donor ligand
directed us to prepare series of related compounds containing
these three halophosphine ligands.
used as a solvent; Booth and Frary8 explored this reaction
in detail, and the byproducts PFBr2 (bp 78 °C) and PF2Br
(bp -16 °C) are much easier to remove. Furthermore, PF2Br
is not very stable under the reaction conditions and dispro-
portionates to PBr3 and PF3. In our hands the reverse addition
of the PBr3 to solid SbF3 and simple passage of the product
through two dry ice traps reproducibly gave pure PF3. The
31P{1H} NMR spectrum of a sample in CDCl3 contained only
PF3 (δ 103.9); PBr3 resonates at δ 229 while PFBr2 and
PF2Br resonate at δ255 and δ195 respectively.23 The gas
phase infrared spectrum of the product was free of impurities.24
Reaction of heptane suspensions of the dimeric compounds
[RuX2(η6-cymene)]2 (1)-(3) with PF3 gas in Rotaflo am-
poules at 70 °C for 4 to 6 h gave high yields of the products
[RuX2(η6-cymene)(PF3)] (4)-(6) (Scheme 1). The microc-
rystalline solids are bright red, red-purple, and purple,
respectively, the color deepening as the halogen atomic
number increases. All of the compounds (1)-(6) show the
expected resonances for the cymene ligand in both their 1H
and 13C{1H} NMR spectra, consistent with rapid ring rotation
about the metal center. The 31P{1H} NMR spectra of (4)-(6)
contained a binomial quartet arising from coupling to the
three fluorine ligands while the 19F{1H} NMR spectra
consisted of a doublet in each case (see Table 1.). The
corresponding spectra were run for PF3 gas dissolved in
CDCl3; the values obtained were δ(31P) 103.9 and δ(19F)
-33.49 with J(31P-19F) -1402.7 Hz. The earliest literature
values were determined many years ago with a permanent
magnet system using a fixed frequency and field sweep
modulation with output to an oscilloscope; the resonance
frequencies corresponded to 10.97 MHz (31P) and 25.49 MHz
(19F). Gutowsky, McCall, and Slichter obtained values of
δ(31P) 97.0 and δ(19F) -33.6 with J(31P-19F) -1416 Hz for
liquid PF3 with this equipment.25 The general sign of
1J(31P-19F) has been shown to be negative from analysis of
second order spectra,26 spin tickling,27,28 and from the
Results and Discussion
Complexes of PF3 and PF2(NMe2). The laboratory scale
generation of trifluorophosphine (bp -101 °C) usually
involves the reaction of phosphorus trichloride (bp 76 °C)
with either hydrogen fluoride gas,10 antimony trifluoride,20
arsenic trifluoride,21 or zinc fluoride.22 These reactions are
stepwise replacements, and the residence time in the reaction
zone is critical in controlling the extent of replacement.
Contamination with the mixed products PFCl2 (bp 14 °C)
and PF2Cl (bp -47 °C) is a potential problem in each case
because of the inconvenient boiling points and necessitates
careful control of reaction conditions and product distillation.
We decided to modify this Swarts reaction approach by
reacting phosphorus tribromide (bp 175 °C) with antimony
trifluoride in the absence of acetonitrile which is normally
(9) Clark, R. J.; Belefant, H.; Williamson, S. M. Inorg. Synth. 1989, 26,
12–17.
(10) Brauer, G. Handbook of PreparatiVe Inorganic Chemistry, 2nd ed.;
Academic Press: New York, 1963; Vol. 1, pp 189-190.
(11) Wilkinson, G. Nature 1951, 168, 514–514.
(12) Schutzenberger, P.; Fontaine, R. Bull. Soc. Chim. 1872, 17, 482–496.
(13) Chatt, J. Nature 1950, 165, 637–638.
(14) Irvine, J. W.; Wilkinson, G. Science 1951, 113, 742–743.
(15) Wilkinson, G. J. Am. Chem. Soc. 1951, 73, 5501–5502.
(16) Rycroft, D. S.; Sharp, D. W. A.; Wright, J. G. Inorg. Nucl. Chem.
Letters 1978, 14, 451–455.
(23) Muller, A.; Niecke, E.; Glemser, O. Z. Anorg. Allg. Chem. 1967, 350,
256.
(17) Davies, M. S.; Aroney, M. J.; Buys, I. E.; Hambley, T. W.; Calvert,
J. L. Inorg. Chem. 1995, 34, 330–336.
(24) Wilson, M. K.; Polo, S. R. J. Chem. Phys. 1952, 20, 1716–1719.
(25) Gutowsky, H. S.; McCall, D. W.; Slichter, C. P. J. Chem. Phys. 1953,
21, 279–292.
(26) Crocker, C.; Goodfellow, R. J. J. Chem. Res. (M) 1981, 742–775.
(27) Cowley, A. H.; White, W. D.; Manatt, S. L. J. Am. Chem. Soc. 1967,
89, 6433–6437.
(18) Frenking, G.; Wichmann, K.; Frohlich, N.; Grobe, J.; Golla, W.; Le
Van, D.; Krebs, B.; Lage, M. Organometallics 2002, 21, 2921–2930.
(19) Hodson, E.; Simpson, S. J. Polyhedron 2004, 23, 2695–2707.
(20) Booth, H. S.; Bozarth, A. R. J. Am. Chem. Soc. 1939, 61, 2927–2934.
(21) Hoffman, C. J. Inorg. Synth. 1953, 4, 149–150.
(22) Williams, A. A. Inorg. Synth. 1957, 5, 95–97.
(28) Manatt, S. L.; Elleman, D. D.; Cowley, A. H.; Burg, A. B. J. Am.
Chem. Soc. 1967, 89, 4544–4545.
9280 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
Table 1. 19F and 31P Chemical Shifts in CDCl3 Solution at 296 K
δ(19F) δ(31P) 1J(PF) Hz
Scheme 2
Scheme 3
Scheme 4
PF3
-33.5 103.9
-25.4 107.6
-21.0 107.8
-11.9 113.3
-1403
-1370
-1346
-1309
[RuCl2(η6-cymene)(PF3)]
[RuBr2(η6-cymene)(PF3)]
[RuI2(η6-cymene)(PF3)]
(4)
(5)
(6)
PF2(NMe2)
-65.9 141.9
-44.6 137.2
-43.3 136.7
-36.1 141.4
-1196
-1177
-1167
-1146
[RuCl2(η6-cymene)(PF2(NMe2))] (7)
[RuBr2(η6-cymene)(PF2(NMe2))] (8)
[RuI2(η6-cymene)(PF2(NMe2))]
(9)
PCl3
219.0
141.8
126.4
107.0
[RuCl2(η6-cymene)(PCl3)]
[RuBr2(η6-cymene)(PCl3)]
[RuI2(η6-cymene)(PCl3)]
(10)
(11)
(12)
PBr3
229.0
69.9
[RuBr2(η6-cymene)(PBr3)]
(13)
P(NMe2)3
118.6
108.7
108.4
109.5
[RuCl2(η6-cymene)(P(NMe2)3)]
[RuBr2(η6-cymene)(P(NMe2)3)]
[RuI2(η6-cymene)(P(NMe2)3)]
(14)
(15)
(16)
analysis of differential line broadening in solution spectra
of the PFO3 ion.29
2-
Treatment of the dimers (1)-(3) with difluoro(dimethy-
lamino)phosphine, PF2(NMe2), in hot heptane produced the
products [RuX2(η6-cymene)(PF2(NMe2))] (7)-(9) by a bridge
1
splitting reaction (Scheme 2). The H and 13C{1H} NMR
spectra are again consistent with free rotation about the
ruthenium-ring axis and ruthenium-phosphorus bond for
each compound. In common with the trifluorophosphine
compounds (4)-(6) there was no observable coupling
between the fluorine atoms and the cymene ring in either
1
the H or 13C{1H} NMR spectra of (7)-(9). All of the
cymene ring carbon atoms were coupled to phosphorus in
the 13C{1H} NMR spectra of (5)-(9); this is unusual in that
normally only the methine carbon atoms show a measurable
coupling and this was indeed the case for (4). The 31P{1H}
and 19F{1H} NMR spectra of (7)-(9) each consist of a
binomial triplet and a doublet respectively and are listed in
Table 1.
1
The lowering of the value of J(31P-19F) on progression
from the free ligand through (4) to (6) and through (7) to
(9) is interesting. A possible explanation is that it is a
consequence of the reduction of the phosphorus-fluorine
bond order. The π- bonding component in the PF3 ligand
has antibonding (σ*) P-F character and is predominantly
P(3p) in nature;30 the ligand is an exceptionally good
π-acceptor,31 and as the halide ligand on ruthenium becomes
less electronegative the π-donation toward the metal center
and the phosphine increases. There are unfortunately no other
complete series of related compounds available for com-
parison, but we note that for cis-[PtCl2(PF3)2] and cis-
These small incremental differences and reversal of our
observed trend coupled with the knowledge that the absolute
sign of 1J(31P-19F) is negative26-29 means that subtle
electronic factors may be operating, and we examine these
in more detail in the computational section (vide infra).
Complexes of PCl3 and PBr3. The reaction of the dimers
(1)-(3) with phosphorus trichloride in hot heptane was
investigated and in each case led to impure products
[RuX2(η6-cymene)(PCl3)] contaminated with starting material
and other organometallic materials. Stirring the reactants
overnight in dichloromethane permitted the isolation of
reasonably pure products which could be further purified by
careful recrystallization (Scheme 3). The red materials
(10)-(12) could be handled in dry air for short periods with
stability increasing with increasing molecular weight. The
compound [RuBr2(η6-cymene)(PBr3)] (13) was prepared
similarly from (2) and phosphorus tribromide (Scheme 4).
1
[PtBr2(PF3)2] the values of J(31P-19F) are 1326 and 1331
Hz, respectively, and for cis-[RhCl(PF3)2]2 and cis-
[RhBr(PF3)2]2 they are 1329 and 1333 Hz, respectively.26
(29) Farrar, T. C.; Quintero-Arcaya, R. A. J. Phys. Chem. 1987, 91, 3224–
3228.
(30) Xiao, S. X.; Trogler, W. C.; Ellis, D. E.; Berkovitch-Yellin, Z. J. Am.
Chem. Soc. 1983, 105, 7033–7037.
(31) Jaw, H. R.; Zink, J. I. Inorg. Chem. 1988, 27, 3421–3424.
Inorganic Chemistry, Vol. 47, No. 20, 2008 9281

Boshaala et al.
Scheme 5
The reaction of the chloro dimer (1) with a small excess
of phosphorus tribromide in heptane was carried out. The
impure product which was insoluble in heptane as was the
dimer (1) was investigated by 1H and 31P{1H} NMR
spectroscopy. The presence of four products was indicated;
signals at δ69.9, 89.4, 108.2, and 126.4 were found in the
31P{1H} NMR spectrum. The first of these signals corre-
sponds to (13) and the last corresponds to (11).
It is clear that halogen exchange has taken place at both
the ruthenium and phosphorus centers. The two other signals
could in principle belong to [RuBr(Cl)(η6-cymene)(PBr3)]
and [RuBr(Cl)(η6-cymene)(PCl3)] but the resonance for the
latter should lie between δ127 and δ140, the values for (10)
and (11). We tentatively assign the resonance at δ89.4 to
[RuBr2(η6-cymene)(PBr2Cl)] and the resonance at δ108.2 to
[RuBr2(η6-cymene)(PBrCl2)] because the incremental shift
difference fits best for the mixed halophosphine series of
dibromoruthenium compounds. The dispersion of the 400
MHz 1H NMR spectrum of the mixed product did not permit
us to confirm that the mixed halide at ruthenium products
were not produced; these should contain diastereotopic
methyl signals in the ring isopropyl substituent and four
chemical shifts for the ring protons of the cymene ligand.
Preliminary experiments with phosphorus triiodide indicate
that (1), (2), and (3) are converted to [RuI2(η6-cymene)(PI3)]
as the sole product, the insolubility of this material both
explaining the drive to a single product and hampering a
full characterization. We have a displacement series where
a heavy PX3 ligand can displace a lighter halogen from a
ruthenium center. The free ligands PCl3 and PBr3 conpro-
portionate rapidly on mixing, and a mixture of the dimers
(1) and (2) also rapidly scrambles halogen ligands in
chloroform or dichloromethane solution. The mean bond
energies for PF3, PCl3, and PBr3 are 499.6, 318.8, and 258.2
kJ mol-1, respectively. Determination of the relative bond
energies in ruthenium-chloride and ruthenium-bromide
systems suggests approximate values of 338 and 256 kJ
mol-1. These values were determined in cyclopentadienyl-
ruthenium systems32,33 but are likely to be reasonable
estimates for the cymeneruthenium case. Redistribution molar
enthalpies for conproportionation should be zero if bond
enthalpies were constant and transferable; generally substi-
tuted phosphines are favored over symmetrical phosphines
reflecting that these bond enthalpies do not behave in that
fashion.34 The use of excess trihalophosphines in these
reactions for synthetic purposes drives the exchanges toward
completion and does not allow speculation on the thermo-
dynamic driving forces behind the exchange reactions.
Scheme 5 illustrates a possible mechanism involving
dissociation of the dimer into two 16 electron fragments (A).
The PBr3 ligand can bind via phosphorus as normal (B) or
could ligate via bromine (D) and exchange halogens via
bridged intermediates (D, E). The metallophosphorane (C)
which is the formal insertion product of PBr3 into the Ru-Cl
bond is also a possible intermediate which could scramble
the halogens by a turnstile process followed by de-insertion.
Bending modes in (C) could also lead to intermediates
resembling (D) and (E). We slightly favor the direct (A),
(D), and (E) route on the grounds that it most closely
resembles the situation that pertains for the fast halide
scrambling between (1) and (2).
Various mechanisms for halogen exchange in free chlo-
rophosphines have been analyzed and the concept of the
phosphorus atom in such compounds having both nucleo-
philic and electrophilic character (biphilicity) was proposed.35
The facile halide exchange reaction between {[Ru(η6-
C6H6)]2(µ-Br)3}BF4 and {[Ru(η6-C6H6)]2(µ-Cl)3}BF4 has
been reported and a tetranuclear intermediate was postu-
lated.36 It is clear that in this cationic case, in neutral
dimer-dimer halide mixing, and the ruthenium-phosphorus
halide mixing above, there are likely to be common
mechanistic elements.
When the reaction of (1) with excess PBr3 was repeated
in dichloromethane solvent the only isolated product was
(13) corresponding to full halogen exchange at ruthenium
and reflecting that all reactants and products were soluble
throughout the reaction. All of the reactions of the dimers
(1)-(3) with PCl3 or PBr3 could be followed in situ by
31P{1H} NMR spectroscopy in deuterochloroform; in par-
ticular the addition of PCl3 to (1) followed by subsequent
addition of PBr3 to the sample supported the dynamic
situation suggested in Scheme 5.
Reaction of dichloromethane or chloroform solutions of
(10)-(13) with ethanol or methanol rapidly and cleanly
produced the phosphite complexes [RuX2(η6-cymene)-
(P{OEt}3)] and [RuX2(η6-cymene)(P(OMe)3)] in isolated
yields of about 60%.19 The trifluorophosphine compounds
(4)-(6) were unreactive under similar conditions. We
tentatively suggest that these reactions probably proceed by
nucleophilic attack on the bound trihalophosphine ligand
rather than ligand dissociation followed by alcoholysis of
the free PX3 ligand and recoordination.
(32) Freeman, S. T. N.; Lemke, F. R.; Haar, C. M.; Nolan, S. P.; Petersen,
J. L. Organometallics 2000, 19, 4828–4833.
(33) Luo, L.; Li, C. B.; Cucullu, M. E.; Nolan, S. P. Organometallics 1995,
14, 1333–1338.
(34) Al-Maydama, H. M. A.; Finch, A.; Gardner, P. J.; Head, A. J. J. Chem.
Thermodyn. 1995, 27, 273–279.
(35) Humbel, S.; Bertrand, C.; Darcel, C.; Bauduin, C.; Juge, S. Inorg.
Chem. 2003, 42, 420–427.
(36) Arthur, T.; Stephenson, T. A. J. Organomet. Chem. 1981, 208, 369–
387.
9282 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
Scheme 6
Preparation and Reactivity of P(NMe2)3 Complexes.
Tris(dimethylamino)phosphine was reacted with the dimers
(1)-(3) overnight in dichloromethane solution. Careful
crystallization lead to the isolation of the dark red products
[RuX2(η6-cymene)(P{NMe2}3)] (14)-(16). Our initial inter-
est in these compounds was to investigate whether one or
more of the nitrogen atoms could be induced to bind to a
second metal center. The X-ray single crystal structure of
tris(dimethylamino)phosphine shows that two nitrogen cen-
ters are planar and sp2 hybridized and the third is pyramidal
sp3 hybridized.37 There is considerable rationalization that
the nitrogen lone pairs are not usually stereochemically
active, and structural studies often show that the geometry
at nitrogen is planar in low valent metal compounds of this
ligand. We began by trying to protonate (14) with aqueous
hexafluorophosphoric acid in dichloromethane-diethylether
to ascertain if one or more of the nitrogen centers was basic.
The sole isolated metal product was [RuCl2(η6-cymene)(PF3)]
(4) in 60% yield (Scheme 6). Reaction of tris(dimethylamino)-
phosphine with aqueous hexafluorophosphoric acid also
produces gaseous phosphorus trifluoride, and it is likely that
the reaction of (14) to yield (4) does not involve the
ruthenium center but is a nucleophilic attack assisted by
protonation at nitrogen to provide a good leaving group.38
While the cleavage of P-N single bonds by haloacids is
well documented the generation of a P-F bond in this
manner has not been reported.39,40 The reaction of
[Cr(CO)5(P{NEt2}3)] with trimethyloxonium tetrafluoroborate
produces [Cr(CO)5(PF{NEt2}2)] and only monofluorination
is observed.41 A related conversion of [Fe(CO)4(PF2NEt2)]
to [Fe(CO)4(PF2Cl)] using hydrogen chloride gas and of
PF2NMe2 to PF2X using anhydrous HX (X ) Cl, Br, I) has
been reported.42,43 Kemmitt et al. have also investigated the
protonolysis of a number of metal complexes of dialkylami-
nophosphine ligands.44 It appears that the nitrogen center in
such ligands is sufficiently basic toward strong acids despite
the delocalization of the lone pair and resultant planarity at
nitrogen.
Computational Analysis of the 1J(P-F) Trends in
1
Complexes (4)-(6). The observed trends for J(31P-19F)
upon substitution of the halide ligands might be caused by
a number of effects. Examples are direct electronic effects
from the halide ligands on the P-F bonds which we might
further subdivide into “chemical” influences (different elec-
tronegativities, electron donor/acceptor strengths, etc.) and
relativistic effects caused by spin-orbit coupling. Because
the changes in the coupling constants are small compared
to their magnitude, we cannot a priori rule out that the trend
is caused by the increasingly strong spin-orbit coupling from
Cl to Br to I and its effect on the magnetic properties of the
complexes.45 Further, the halide ligands might cause changes
in the P-F coupling constants indirectly via small differences
in the geometries. The most complicated scenario would be
if all these effects contribute to the trend with approximately
equal magnitude.
To investigate the magnitude of some of the aforemen-
1
tioned possible influences on J(P-F) we have performed
calculations for the [RuX2(η6-cymene)(PF 3)], X ) Cl, Br, I
(41) Hofler, M.; Stubenrauch, M.; Richarz, E. Organometallics 1987, 6,
198–199.
(37) Mitzel, N. W.; Smart, B. A.; Dreihaupl, K. H.; Ranin, D. W. H.;
Schmidbaur, H. J. Am. Chem. Soc. 1996, 118, 12673–12682.
(38) Febvay, J.; Casabianca, F.; Riess, J. G. J. Am. Chem. Soc. 1984, 106,
7985–7986.
(39) Montemayor, R. G.; Parry, R. W. Inorg. Chem. 1973, 12, 2482–2484.
(40) Kraihanzel, C. S. J. Organomet. Chem. 1974, 73, 137–185.
(42) Douglas, W. M.; Ruff, J. K. J. Chem. Soc. A. 1971, 3558–3561.
(43) Bauer, D. P.; Douglas, W. M.; Ruff, J. K. Inorg. Synth. 1976, 16,
63–68.
(44) Dyer, P. W.; Fawcett, J.; Hanton, M. J.; Kemmitt, R. D. W.; Padda,
R.; Singh, N. J. Chem. Soc., Dalton Trans. 2003, 10, 4–113.
(45) Autschbach, J.; Ziegler, T. J. Chem. Phys. 2000, 113, 9410–9418.
Inorganic Chemistry, Vol. 47, No. 20, 2008 9283

Boshaala et al.
Table 2. Experimental and Calculated P-F Spin-Spin Coupling
from experimental data is 11% in each case and within the
expected error bars of the theoretical method.48
1
Constants J(31P-19F) for [RuX2(η6-cymene)(PF3)], X ) Cl, Br, and I
(in hertz)
Using the much larger QZ4P basis for the Ru, P, and F
atoms yields similar results although the agreement with
experiment is slightly worse. We have observed this also in
other calculations of the NMR parameters of Ru complexes49
as well as Pt and Hg complexes.50,51 and found recently that
the use of the TZP basis seems to compensate to some extent
for neglecting unspecific solvent effects.50 (i.e., this basis
provides a somewhat more balanced cancelation of errors).
For PF3, the calculated coupling constant is smaller in
magnitude than for the complexes when using a non-hybrid
functional (ZSC, ZSO), and similar to the coupling in the
Cl complex when using a hybrid functional (B3LYP).
Experimentally, the P-F coupling in PF3 is larger in
magnitude than for the complexes. However, the experi-
mental PF3 value is obtained from a solution in CDCl3
whereas the calculation is for the gas phase. We have also
performed calculations using a continuum solvent model
which, however, did not change the results significantly. For
complexes
ZSO/BPe ZSC/BPf ECP/B3LYPg expt.
[RuCl2(η6-cymene)(PF3)] (a) -1540 -1552
(b) -1556 -1567
-1608
-1625
-1604
-1578
-1593
-1578
-1521
-1541
-1554
-1546
-1593
-1628
-1370
(c) -1536 -1548
[RuBr2(η6-cymene)(PF3)] (a) -1507 -1520
(b) -1522 -1534
-1346
(c) -1507 -1520
(d) -1450 -1460
[RuI2(η6-cymene)(PF3)] (a) -1466 -1482
(b) -1480 -1493
-1309
-1403
(c) -1470 -1485
(a) -1419 -1419
(b) -1496 -1502
PF3
a Optimized geometries, i.e. ZSO/BP/TZP//ZSC/BP/TZP, ZSC/BP/TZP//
ZSC/BP/TZP, and ECP/B3LYP//ZSC/BP/TZP, respectively. b Same as (a)
but geometries obtained with the QZ4P basis for Ru, P, and F; TZP for the
other atoms. J-couplings calculated at the ZORA level (ZSO, ZSC) also
based on this basis set. c Same as (a) but with fixed P-F bond length taken
from optimized structure of Br complex. d Same as (c) but based on
experimental structure of Br complex. e Relativistic ZORA spin-orbit
calculation, BP functional, Slater-type basis. f Spin-free (scalar) ZORA
calculation, BP functional, Slater-type basis. g B3LYP hybrid functional,
scalar relativistic ECP for Ru, Gaussian-type basis.
1
the complexes, a uniform increase of J(P-F) of 7 Hz was
obtained. The excellent agreement between theory and
experiment for some of the calculations on PF3 is therefore
partially due to error compensation. A modeling of PF3 in
solution, as well as the dynamic solvation of the complexes,
is beyond the scope of this work. It should be pointed out
that while it is challenging to obtain significantly smaller
error bars for the computation of J-couplings in metal
complexes, the trends for 1J(P-F) among these very similar
complexes are correctly reproduced. Since the results are well
within the deviations between density-functional theory
(DFT) and experiment typically found for computations of
J-coupling in metal complexes,48 meaningful answers can
be obtained from an analysis of the data in Table 2.
series. Details of the computational procedure are provided
in the Computational Details section. Geometry optimizations
with the “BP” generalized gradient approximation (GGA)
functional (at the scalar ZORA (ZSC) level) yielded average
P-F bond lengths of 1.612, 1.592, 1.594, and 1.596 Å for
PF3, [RuCl2(η6-cymene)(PF3)], [RuBr2(η6-cymene)(PF3)], and
[RuI2(η6-cymene)(PF3)], respectively. The P-F bond length
is very slightly increasing from chloride to the iodide
complex and shorter than the P-F equilibrium bond distance
calculated for PF3 in the gas phase. Compared to experi-
mental bond lengths of 1.569 and 1.509 Å for PF3 and the
Br complex the computations overestimate the bond distances
somewhat which is an expected outcome with this type of
density functional.46 Using the Vosko-Wilk-Nusair local
density approximation (LDA) functional,47 the bond lengths
are 1.590, 1.569, 1.571, and 1.573 Å, respectively, which
agree better with experiment but are still somewhat too large.
We have confirmed that the trend for the calculated
spin-spin coupling constants does not change when geom-
etries optimized with the LDA functional are employed
instead. Results reported below are therefore based on
geometries obtained with the BP functional in consistency
with most of the NMR computations. The computed values
The first question that we seek to answer is whether
spin-orbit coupling, a relativistic effect that increases with
the nuclear charge of the halide ligand,52,53 might be
responsible for the observed trend for 1J(P-F). A comparison
of the scalar (ZSC) and the spin-orbit (ZSO) relativistic data
in Table 2 shows that this is not the case. Although the trend
1
for J(P-F) due to spin-orbit effects has the right sign, it
is roughly an order of magnitude smaller than what is
observed experimentally. The overall magnitude of the
spin-orbit contributions to the P-F coupling constants is
only about 1% and for the most part originating from the
Ru atom.
Regarding the mechanisms of J-coupling other than
spin-orbit terms, it was found that contributions from the
1
of J(P-F) are listed in Table 2. The trend obtained for the
calculated coupling constants for the Ru complexes has the same
sign and roughly the same magnitude as seen experimentally.
Overall, the agreement with experiment is reasonable. The
hybrid functional (B3LYP) calculations yield larger magnitudes
for 1J(P-F) than the ZSC and ZSO calculations with the non-
hybrid BP functional. The couplings calculated with the TZP
basis at the ZORA spin-orbit (ZSO) level are closest to the
experiment, with remaining differences of 170, 161, and 157
Hz for the Cl, Br, and I complex, respectively. The deviation
(48) Autschbach, J. The calculation of NMR parameters in transition metal
complexes. In Principles and Applications of Density Functional
Theory in Inorganic Chemistry I; Kaltsoyannis, N., McGrady, J. E.,
Eds.; Springer: Heidelberg, 2004; Vol. 112, pp 1-48.
(49) Autschbach, J.; Zheng, S. Magn. Reson. Chem. 2006, 44, 989–1007.
(50) Sterzel, M.; Autschbach, J. Inorg. Chem. 2006, 45, 3316–3324.
(51) Jokisaari, J.; Jarvinen, S.; Autschbach, J.; Ziegler, T. J. Phys. Chem.
A. 2002, 106, 9313–9318.
(52) Pyykko, P. Chem. ReV. 1988, 88, 563–594.
(46) Koch, W.; Holthausen, M. C. A Chemist’s Guide to Density Functional
Theory;Wiley-VCH: Weinheim, 2001.
(47) Vosko, S. H.; Wilk, L.; Nusair, M. Can. J. Phys. 1980, 58, 1200–
1211.
(53) Autschbach, J.; Ziegler, T., Relativistic Computation of NMR shield-
ings and Spin-spin Coupling Constants. In Encyclopedia of Nuclear
Magnetic Resonance; Grant, D. M., Harris, R. K., Eds.; John Wiley
& Sons: Chichester, 2002; Vol. 9, pp 306-323.
9284 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
relativistic analog53,54 of the Fermi contact term (FC) differed
by 25 Hz between the Cl and the Br, and by 30 Hz between
the Br and the I complex, respectively, at the ZSC level.
These differences are of similar magnitude as the experi-
mental differences of 24 and 37 Hz. A more detailed analysis
can therefore focus on the isotropic FC term only.
Next we investigate indirect structural effects. To this end,
we have performed calculations of 1J(P-F) for model
systems where the P-F distances in the Cl and I complexes
have been set to the same values as those of the optimized
Br complex. The difference in the calculated 1J(P-F)
between the Cl and Br complex was 29 Hz, and between
the Br and I complex it was 37 Hz (ZSO level). With the
fully optimized structures for the chloride and iodide complex
we obtained 33 and 41 Hz instead (Table 2). The differences
in 1J(P-F) (29/37 Hz for the fixed geometries versus 33/41
Hz for the fully optimized systems) are similar. This shows
that indirect structural factors are not the main reason for
the trend in 1J(P-F) since their contributions are of the same
magnitude as the spin-orbit effects and therefore signifi-
cantly smaller than the total changes in 1J(P-F). Therefore,
we conclude that direct electronic effects other than spin-orbit
coupling are the main reason for the observed trend. For such
effects to be strong even when the moieties are separated
by several chemical bonds, one might suspect that the
complexes have a somewhat delocalized electronic structure.
This expectation has been confirmed by our calculations, as
will be discussed below in the context of the natural localized
molecular orbital-natural bond order (NLMO/NBO) analysis
of the P-F coupling (see Computational Details).
Spin-spin coupling constants can be analyzed using
molecular orbital (MO) theory.55 For instance, according to
eq 2 from the Computational Details section, we can identify
contributions to 1J(P-F) from individual occupied MOs. The
fact that Kohn-Sham DFT is based on molecular orbitals
is particularly useful in this context since it allows to perform
such analyses on first-principles theoretical results that are
in good agreement with experiment.
For reasons stated above, the analysis focused on the
isotropic FC term only. According to our calculations the
main contributing orbitals are numbers 58, 76, and 92 for
the Cl, Br, and I complexes, respectively, shown in Figure
1. (The different orbital numbering in the three complexes
is due to the different number of core shells at the halides.)
The contributions to 1J(P-F) from these orbitals are -1572,
-1558, and -1512 Hz, respectively. As is typical for MO
decompositions of spin-spin coupling constants55 there is
an accompanying large contribution of opposite sign. Here,
the P-F centered orbitals numbers 57, 65, and 83 contribute
+573, +564, and +559 Hz in the Cl, Br, and I complexes,
respectively. The two sets of orbitals which were identified
here as the biggest contributors to 1J(P-F) are qualitatively
the same as those calculated for free PF3. The sign of the
trend for the sum, as well as for the largest individual MO
contributions, is the same as in the experiment, but the trend
is strongly overestimated and there are a large number of
Figure 1. P-F bonding occupied molecular orbitals with large phosphorus
σ-bond character in [RuX2(η6-cymene)(PF3)], X ) Cl, Br, and I. Shown
here are orbitals # 65 (left) and 76 (right) for the Br complex. The equivalent
orbitals for the Cl (# 47, 58) and I (# 83, 92) complex are visually
indistinguishable from this orbital and therefore not shown.
additional MOs contributing to 1J(P-F) with varying signs.
These contributions add up to several hundred hertz. It was
not possible to identify a single or a few MOs that would
yield most of the observed trend. From the MO analysis it
1
appears that the trend J(P-F) in the complexes is in part
caused by a small perturbation of the PF3 orbitals and by a
large number of small but significant contributions from other
MOs which are mainly centered on the metal and the other
ligands but have small amplitudes on the PF3 moiety. These
findings are in line with the statement made above about
“subtle electronic effects”. We interpret this situation as the
complexes possessing a somewhat delocalized electronic
structure in which the halide ligands can have electronic
influence on the P-F bonds and therefore affect the P-F
coupling constant. The subtlety of these effects is highlighted
by the fact that a “fragment orbital” analysis56 performed
by us did not find any significant direct contributions from
1
the halide atomic orbitals to J(P-F).
To support the conclusions from the MO analysis we have
developed a program for the analysis of spin-spin coupling
constants obtained from relativistic DFT computations using
“natural” localized molecular orbitals (NLMOs) and natural
bond orbitals (NBOs) as described in the Computational
Details section. The analysis closely follows the “natural”
shielding and spin-spin coupling analyses proposed by
Bohmann et al.57 and decomposes the J-coupling into terms
from perfectly localized Lewis-type (L) bond and lone-pair
orbitals (“natural bond orbitals” or NBOs) and additional
delocalized non-Lewis (NL) terms for each parent NBO. The
analysis can be applied to couplings involving light, as well
as heavy, nuclei. The $CHOOSE keyword was applied in
the NBO computations to obtain P-F bonding and Ru-P
bonding parent NBOs for the set of NLMOs used for the
analysis. As with the other analyses (MO and fragment
orbitals) discussed here, a considerable number of NLMOs
contribute to the final result, and it was not possible to
determine a single orbital or a sum of a few orbitals that
would yield the exact magnitude for the trend. Some of the
contributions are listed in Table 3.
1
The biggest contributors to J(P-F) are fluorine valence
lone pair orbitals with large F 2s character, the Ru-P bond,
(56) Autschbach, J.; Igna, C. D.; Ziegler, T. J. Am. Chem. Soc. 2003, 125,
1028–1032.
(54) Autschbach, J.; Ziegler, T. J. Am. Chem. Soc. 2001, 123, 3341–3349.
(55) Autschbach, J.; Le Guennic, B. Chem.sEur. J. 2004, 10, 2581–2589.
(57) Bohmann, J. A.; Weinhold, F.; Farrar, T. C. J. Chem. Phys. 1997,
107, 1173–1184.
Inorganic Chemistry, Vol. 47, No. 20, 2008 9285

Boshaala et al.
Table 3. Averaged Fluorine Core Orbital (C), Valence Lone Pair (LP),
charge when going from the free ligand to the complexes,
along with a slight increase in the populations of the
antibonding P-F σ* NBOs. These results highlight the
considerable metal ligand back bonding capability of PF3
which has recently been analyzed in detail (along with other
ligands of the type YX3) by Leyssens et al.59 The participa-
tion of the P-F antibonding orbitals in the back-donation
helps to rationalize the results from the NLMO analysis of
1J(P-F).
1
Ru-P, Ru-X and P-F bonding (B) NLMO Contributions to J(P-F)
in [RuX2(η6-cymene)(PF3)], X ) Cl, Br, and I (in hertz)a
complex/NLMO
B(Ru-X) F(LP) F(C) B(P-F) B(Ru-P)
[RuCl2(η6-cymene)(PF3)]
[RuBr2(η6-cymene)(PF3)]
[RuI2(η6-cymene)(PF3)]
-2
4
-1
-613 -316
-613 -314
-603 -313
235
234
233
-447
-434
-415
a The summations of these five main contributions yield -1143, -1123,
and -1099 Hz for the Cl, Br, and I complexes, respectively. These five
main contributions represent the correct trend, and the summations yields
approximately 70% of the total computed J(P-F).
Among the analysis tools employed here the NLMO
analysis provides the clearest evidence for a direct involve-
ment of the halide orbitals in the P-F spin-spin coupling
via participation in a somewhat delocalized Ru-P bond. We
1
attribute the small decrease in the magnitude of J(P-F)
along the series Cl, Br, and I to an increased delocalization
of charge away from the PF3 moiety. These effects are indeed
rather subtle and highlight some of the general difficulties
of analyzing trends for NMR parameters in transition metal
complexes because of a complicated interplay of metal and
ligand orbitals where some amount of delocalization is not
uncommon.54,56,60-62 It appears, however, that a NLMO
analysis is helpful in such cases to address such questions
of delocalization and to pick out the main contributing
orbitals to the NMR spin-spin coupling.62
Crystal Structural Determinations. The single crystal
X-ray structures of (5), (8), and (16) were determined to
provide a series of related compounds containing the PF3,
PF2(NMe2), and P(NMe2)3 ligands in a relatively sterically
unhindered environment. The collection and refinement
parameters are shown in Table 4, and selected bond lengths
and bond angles are given in Table 5.
Figure 2. One of three Ru-P sigma-bonding NLMO in [RuX2(η6-
cymene)(PF3)]: 3D isosurface (0.03 au) and 2D contour plots in planes
through Ru-P-F and X-Ru-P. Contour line values: 0.01 to 3.00. Shown
here are the orbitals for the X ) Br complex. The corresponding orbitals
for the Cl and I complex are very similar and therefore not shown.
the fluorine 1s orbitals, and P-F bond. The first two
contributions are intuitive and similar to the outcome of a
fragment orbital analysis.58,61,62 The 1s contributions are
large but mostly transferable between the complexes and
therefore do not need to be considered for the trend in
1J(P-F). Ru-X bond contributions are not significant for
the trend but listed for completeness.
The most interesting contributions originate from the
Ru-P bond NLMOs as listed in Table 3 (NLMO #3 in each
case). Visualizations of one of these orbitals are shown in
Figure 2. The contributions from this NLMO yield the correct
trend for 1J(P-F) although its magnitude does not completely
The interligand angle at phosphorus in gaseous PF3 is
97.7(2)° with the P-F bond length being 1.569(1) Å;63 the
average P-F bond length in (5) (Figure 3) is 1.509(8) Å
which is an appreciable shortening. This parameter covers
the range from 1.51-1.57 Å in the reported structures in
the literature with most determinations finding about 1.55Å;
we repeateded our determination using a second crystal and
obtained an average value of 1.508(9) Å and conclude that
the bond shortening is significant. The Ru-P bond length
of 2.184 Å in (5) compares well with 2.178 Å and 2.206(2)
1
account for the differences in J(P-F) between the Cl, Br,
and I complexes. According to the NLMO analysis of the
J-coupling, the non-Lewis (NL, delocalization) terms from
these orbitals amount to about 15% of their total contribution
to 1J(P-F). In each case the parent Ru-P bond NBO has a
small (∼ 0.4%), but obviously significant, involvement of
each halide ligand which increases along the series Cl, Br,
and I along with contributions from the fluorine atoms. The
latter contributions are clearly visible in the contour line
diagrams in Figure 2, while the halide contributions only
become visible if contour lines with values below 0.01 are
included. Additional information about the influence of the
metal and the other ligands on the PF3 moiety is obtained
from the composition of the atomic hybrid orbitals to the
NLMOs, as determined by the NBO computation. For the
P-F bonding NLMOs, we find that the contributing phos-
phorus AO has roughly 10% s character in the computation
for free PF3 but approximately 20% s character in the
complexes. There is also an increase in the phosphorus
Å
in [RuCl2{η2:η3-CH2dC(Me)CH(PCy3)(CH2)2CHC-
(Me)CH2}(PF3)] and trans-[Ru(H)(PF3)(dppm)2]BF4, respec-
tively.64,65
The free ligand difluoro(dimethylamino)phosphine has
been structurally characterized in the solid state, and the P-F
and P-N bond lengths are 1.610(4) Å and 1.626(5) Å,
respectively, with angles of 91.5(3)° and 101.6(2)° for
F-P-F and F-P-N, respectively.66 There is a small
shortening of the P-F bond in (8) relative to the free ligand
(59) Leyssens, T.; Peters, D.; Orpen, A. G.; Harvey, J. N. Organometallics
2007, 26, 2637–2645.
(60) Autschbach, J.; Ziegler, T. J. Am. Chem. Soc. 2001, 123, 5320–5324.
(61) Le Guennic, B.; Matsumoto, K.; Autschbach, J. J. Magn. Reson. Chem.
2004, 42,, S99-S116.
(62) Autschbach, J.; Le Guennic, B. J. Chem. Educ. 2007, 84, 156–171.
(63) Williams, Q.; Sheridan, J.; Gordy, W. J. Chem. Phys. 1952, 20, 164–
167.
(58) Chen, W.; Liu, F; Matsumoto, K.; Autschbach, J.; Le Guennic, B.;
Ziegler, T.; Maliarik, M.; Glaser, J. Inorg. Chem. 2006, 45, 4526–
4536.
(64) Nanishankar, H. V.; Nethaji, M.; Jagirdar, B. R. Eur. J. Inorg. Chem.
2004, 3048–3056.
9286 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
Table 4. Data Collection and Refinement Parameters for (5), (8), and (16)
Identification code
empirical formula
formula weight
temperature
(5)
(8)
(16)
C16H32I2N3PRu
652.29
C10H14Br2F3PRu
483.07
223(2) K
C12H20Br2F2NPRu
508.15
294(2) K
294(2) K
wavelength
0.71073 Å
0.71073 Å
0.71073 Å
crystal system
space group
orthorhombic
Fdd2
monoclinic
P21/n
monoclinic
P21/c
unit cell dimensions
a ) 25.809(3) Å, R ) 90°
b ) 26.015(4) Å, ꢀ ) 90°
c ) 9.0051(11) Å, γ ) 90°
6046.3(13) Å3
16
a ) 9.5131(5) Å, R ) 90°
b ) 11.3369(12) Å, ꢀ ) 103.033(6)°
c ) 15.6280(12) Å, γ ) 90°
1642.0(2) Å3
a ) 9.6415(7) Å, R ) 90°
b ) 15.1527(11) Å, ꢀ ) 103.664(7)°
c ) 15.666(2) Å, γ ) 90°
2223.9(3) Å3
volume
Z
density (calculated)
absorption coefficient
F(000)
crystal size
theta range for data collection
index ranges
4
4
2.123 Mg/m3
2.055 Mg/m3
1.948 Mg/m3
6.438 mm-1
3680
5.925 mm-1
3.556 mm-1
984
1256
0.35 × 0.25 × 0.25 mm3
2.22 to 27.50°.
-33 e h e 1
0.30 × 0.25 × 0.25 mm3
2.24 to 27.50°.
-12 e h e 1
0.30 × 0.25 × 0.25 mm3
1.90 to 28.50°.
-12 e h e 1
-1e k e 33
-14 e k e 1
-1 e k e 20
-1 e l e-11
2242
-20 e l e 20
4856
-20 e l e 21
7056
reflections collected
independent reflections
refinement method
data/restraints/parameters
goodness-of-fit on F2
final R indices [I > 2sigma(I)]
R indices (all data)
2046 [R(int) ) 0.0272]
full-matrix least-squares on F2
2046/1/154
3752 [R(int) ) 0.0232]
full-matrix least-squares on F2
3752/0/173
5619 [R(int) ) 0.0326]
full-matrix least-squares on F2
5617/0/208
1.034
1.048
1.080
R1 ) 0.0332, wR2 ) 0.0705
R1 ) 0.0430, wR2 ) 0.0747
0.542 and -0.562 e Å-3
R1 ) 0.0315, wR2 ) 0.0714
R1 ) 0.0420, wR2 ) 0.0756
0.559 and -0.649 e Å-3
R1 ) 0.0366, wR2 ) 0.0796
R1 ) 0.0525, wR2 ) 0.0859
0.562 and -1.284 e Å-3
largest diff. peak and hole
Table 5. Selected Bond Lengths (Å) and Bond Angles (deg) for (5), (8), and (16)
(5)
(8)
(16)
(5)
(8)
(16)
Ru(1)-P(1)
Ru(1)-Br(1)
Ru(1)-Br(2)
Ru(1)-I(1)
Ru(1)-I(2)
P(1)-F(1)
P(1)-F(2)
P(1)-F(3)
P(1)-N(1)
P(1)-N(2)
P(1)-N(3)
2.184(2)
2.5267(11)
2.5253(9)
2.2446(9)
2.5127(5)
2.5351(5)
2.3657(11)
Br(1)-Ru(1)-Br(2)
I(1)-Ru(1)-I(2)
Br(1)-Ru(1)-P(1)
Br(2)-Ru(1)-P(1)
I(1)-Ru(1)-P(1)
I(2)-Ru(1)-P(1)
F(1)-P(1)-F(2)
F(2)-P(1)-F(3)
F(1)-P(1)-F(3)
F(1)-P(1)-N(1)
F(2)-P(1)-N(1)
N(1)-P(1)-N(2)
N(2)-P(1)-N(3)
N(1)-P(1)-N(3)
89.30(4)
88.16(2)
90.303(14)
83.85(9)
85.86(7)
86.96(3)
87.08(3)
2.7416(5)
2.7359(4)
91.83(3)
88.79(3)
1.510(10)
1.516(6)
1.502(8)
1.563(2)
1.571(2)
97.4(5)
97.6(5)
97.2(6)
94.64(15)
1.612(4)
1.673(3)
1.671(4)
1.667(4)
101.02(18)
103.86(17)
104.2(2)
100.3(2)
105.9(2)
which is not so pronounced as that observed in (5) with other
ligand parameters being essentially unchanged on coordina-
tion to the ruthenium center; this determination is the first
report of a platinum group metal complex of this ligand
(Figure 4). The angle sum around N(1) is 358.9° reflecting
the rehybridization of the nitrogen lone pair also observed
in the free ligand.
The three angle sums at nitrogen in (16) are 357.3°, 359.4°,
and 360.0° indicating trigonal planar geometry at all three
nitrogen centers (Figure 5) in contrast to the free ligand.37
This geometry is commonly found on coordination to a metal
center67,68 but in the iron complex [Fe(CO)3(P{NMe2}3)2]
one of the aminophosphine ligands has a geometry compa-
rable to the free ligand. It has been suggested that the barrier
to inversion at nitrogen is low for this ligand.
The Ru-P bond lengths of (5), (8), and (16) show a
progressive lengthening associated with increasing σ-donor
strength and decreasing π-donor strength of the phosphine
ligands.69
(65) Werner, H.; Stuer, W.; Jung, S. F.; Weberndorfer, B.; Wolf, J. Eur.
J. Inorg. Chem. 2002, 1076–1080.
(66) Morris, E. D.; Nordman, C. E. Inorg. Chem. 1969, 8, 1673–1676.
(67) Brunet, J. J.; Diallo, O.; Donnadieu, B.; Roblou, E. Organometallics
2002, 21, 3388–3394.
(68) Wang, K.; Emge, T. J.; Goldman, A. S. Organometallics 1994, 13,
2135–2137.
Figure 3. X-ray single crystal structure of (5). Thermal ellipsoids are drawn
at the 50% probability level.
Inorganic Chemistry, Vol. 47, No. 20, 2008 9287

Boshaala et al.
ruthenium bound halide ligands with heavier halide ligands
initially bound to phosphorus. This uncommon process
in non-polar media has been explained by suggesting that
the PX3 molecule can bind to a metal center either by a
conventional metal-phosphorus bond or by a halide to
metal donor bond producing a four center intermediate
which undergoes asymmetric bridge cleavage. The simi-
larity of this process to the rapid halide ligand scrambling
observed when, for example, (1) and (2) are mixed inclines
us to slightly disfavor an alternative metallophosphorane
pathway at present. Since the fluoro dimer [RuF2(η6-
cymene)]2 is unknown and has resisted our synthetic
efforts, we are unable to settle this mechanistic question
by well established NMR techniques, the remaining
halogens being quadrupolar and therefore ruling out
exchange studies and identification of intermediates using
31P NMR observation. Similarly the alcoholysis and
protonation reactions could involve five coordinate met-
allophosphorane intermediates but in these cases as in the
halide scrambling reactions we favor simple pathways that
most closely resemble well established organic reaction
pathways. It is to be hoped that others will perform
appropriate calculations to settle this point.
Figure 4. X-ray single crystal structure of (8). Thermal ellipsoids are drawn
at the 50% probability level.
Study of two series of complexes [RuX2(η6-cyme-
ne)(PF3)] and [RuX2(η6-cymene)(PF2(NMe2))] reveals a
1
decrease in J(P-F) as the halide ligand is changed from
chloride through to iodide; calculation studies suggest that
the electronic and orbital effects are subtle. From a
computational analysis in terms of localized orbitals, the
trend has been shown to originate from an involvement
of the halide orbitals in a somewhat delocalized ruthenium-
phosphorus bond while several other possible factors such
as geometry differences among the complexes or spin-orbit
coupling at the halide centers were ruled out as sources
for the trends.
Figure 5. X-ray single crystal structure of (16). Thermal ellipsoids are
drawn at the 50% probability level.
Conclusions
Experimental Section
The half-sandwich cymeneruthenium moiety [RuX2(η6-
cymene)] has been shown to provide a stable platform for
the coordination of trihalophosphine ligands PF3, PCl3, and
PBr3. Tris(dimethylamino)phosphine complexes have also
been prepared, and a small number of reactions have been
carried out to investigate the reactivity of the four bound
ligands. Alcoholysis of the PCl3 and PBr3 but not the PF3
complexes proceeds in good yield resulting in the corre-
sponding trialkylphosphite complexes. The conversion of the
coordinated tris(dimethylamino)phosphine ligand in [RuX2(η6-
cymene)(P{NMe2}3)] (14)-(16) by reaction with aqueous
hexafluorophosphoric acid to a coordinated trifluorophos-
phine ligand resulting in the isolation of [RuX2(η6-cyme-
ne)(PF3)] (4)-(6) has been observed. Both of these reactions
may well proceed as an example of nucleophilic attack at
ligand chemistry rather than involving dissociation-association
chemistry.
All reactions and preparations were carried out on a vacuum/
nitrogen line using standard Schlenk-tube techniques. Diethylether,
hexane, heptane, and petroleum ether (40-60 °C) were dried over
sodium wire and distilled under nitrogen. Dichloromethane was
dried over barium oxide and distilled under nitrogen. All solvents
were degassed prior to use. All products isolated were dried under
reduced pressure, in a hot water bath for at least 1 h. Infrared spectra
were recorded on a Bruker Vector 22 FTIR instrument; only
significant absorption bands are reported. NMR spectra were
1
recorded on Bruker Avance 300 (300.13 MHz, H; 75.47 MHz,
13C; 121.49 MHz 31P) and Bruker Avance 400 (400.13 MHz, H;
1
376.50 MHz 19F; 100.62 MHz, 13C; 161.98 MHz 31P) spectrometers.
All 1H and 13C NMR chemical shifts are expressed in ppm relative
to residual protonated solvent. The high-frequency positive conven-
tion was followed for 19F chemical shifts (1% C6F6 in CDCl3
-162.60 ppm) and 31P NMR chemical shifts (1% P(OPh)3 in CDCl3
+126.5 ppm). All NMR and infrared spectra were measured at room
temperature. Standard Bruker microprograms were used for the
acquisition of HETCORR, NOESY, and COSY-45 spectra. El-
emental analyses were obtained at Manchester University Analytical
laboratories. Fast Atom Bombardment (FAB) mass spectra were
Reaction of the dimers [RuX2(η6-cymene)]2 (1)-(3)
with trihalophosphines led in some cases to exchange of
(69) Yarbrough, L. W.; Hall, M. B. Inorg. Chem. 1978, 17, 2269–2275.
9288 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
obtained on a Kratos Concept S1 spectrometer. The dimers
[RuX2(η6-cymene)]2 (X ) Cl19, Br, I70) were prepared by literature
methods.
(s, CH(CH3)2), 19.51 (s, CH3-ring); 19F{1H} NMR (CDCl3): δ
-21.0 (d, J(P-F) 1346 Hz).
[RuI2(η6-cymene)PF3] (6). (Found: C, 20.34; H, 2.42%;
1
Phosphorus trichloride, phosphorus tribromide, and tris(dim-
ethylamino)phosphine were obtained from Aldrich and transferred
to Rotaflo ampoules for storage under nitrogen. Dichloro(dimethy-
lamino)phosphine was prepared by a literature method71 and
converted to difluoro(dimethylamino)phosphine by treatment with
antimony trifluoride in the absence of solvent.72,73 Trifluorophos-
phine (0.01-0.02 mol) was prepared by dropwise addition of PBr3
to excess powdered SbF3; the use of a nitrogen gas sweep,
entrainment through two traps (-78 °C), and collection at -196
°C produced a pure product (31P and 19F NMR analysis).
Caution! Trifluorophosphine is a Very toxic gas and should be
handled in a well Ventilated area by experienced personnel. The
scale used in the experimental section presents a minimal but finite
hazard.
C10H14F3P1I2Ru calcd: C, 20.81; H, 2.45%); H NMR (CDCl3): δ
1.29 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.59 (s, 3H, CH3-ring),
3.15 (sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.74 (d, J(HH) 7.0 Hz,
2H, CH-ring), 5.89 (d, J(HH) 7.0 Hz, 2H, CH-ring); 31P{1H} NMR
(CDCl3): δ 113.3 (q, J(P-F) 1309 Hz); 13C {1H} NMR (CDCl3):
δ 116.56 (s, C1-ring), 109.32 (s, C4-ring), 91.55 (d, J(P-C) 8.0
Hz, C2,6-ring), 91.96 (d, J(P-C) 6.0 Hz C3,5-ring), 32.11 (s,
CH(CH3)2), 22.61 (s, CH(CH3)2), 20.65 (s, CH3-ring); 19F{1H}
NMR (CDCl3): δ -11.9 (d, J(P-F) 1309 Hz).
Preparation of [RuX2(η6-cymene)(PF2(NMe2)], X ) Cl (7),
Br (8), I (9). The appropriate dimer compound [RuX2(η6-cymene)]2
(0.5-0.8 g) was suspended in heptane (30 mL) in a Rotaflo ampule
(125 mL) equipped with a magnetic flea. Difluoro(dimethylami-
no)phosphine (0.3 mL, excess) was added, and the reactants were
degassed and saturated with nitrogen gas. Stirring at 70 °C for 6-12
h produced visible color changes. The cooled suspensions were
filtered, washed with pentane (2 × 20 mL), and dried under reduced
pressure. Isolated yields were essentially quantitative of bright red,
red-purple, and purple solids respectively.
[RuCl2(η6-cymene)(PF2(NMe2)] (7). (Found: C, 34.18; H, 4.83;
N, 3.27%; C12H20F2Cl2N1P1Ru calcd: C, 34.38; H, 4.81; N, 3.34%);
1H NMR (CDCl3): δ 1.22 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.19
(s, 3H, CH3-ring), 2.86 (dt, J(P-H) 11 Hz, J(F-H) 3 Hz, 6H,
PF2(NMe2), 2.88 (sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.55 (d,
J(HH) 6.1 Hz, 2H, CH-ring), 5.68 (d, J(HH) 6.1 Hz, 2H, CH-ring);
31P{1H} NMR (CDCl3): δ 137.2 (t, J(P-F) 1177 Hz); 13C {1H}
NMR (CDCl3): δ 110.89 (d, J(P-C) 2 Hz, C1-ring), 104.56 (d,
J(P-C) 2 Hz, C4-ring), 90.68 (d, J(P-C) 6.5 Hz, C2,6-ring), 89.68
(d, J(P-C) 5.5 Hz, C3,5-ring), 36.72 (d, J(P-C) 6.5 Hz,
PF2(NMe2), 30.64 (s, CH(CH3)2), 21.88 (s, CH(CH3)2), 18.37 (s,
CH3-ring). 19F NMR (CDCl3): δ -44.55 (d sept, J(P-F) 1177 Hz,
J(F-H) 3 Hz).
Preparation of [RuX2(η6-cymene)(PF3)], X ) Cl (4), Br
(5), I (6). The appropriate dimer compound [RuX2(η6-cymene)]2
(0.5-0.8 g) was suspended in heptane (30 mL) in a Rotaflo ampule
(175 mL) equipped with a magnetic flea. The reactants were
degassed, and the ampule was filled with nitrogen gas. The ampule
was placed in a liquid nitrogen bath, and freshly prepared
trifluorophosphine (0.01-0.02 mol) was swept into the ampule
through a lead through adaptor where it was observed to freeze
onto the walls of the ampule as a white film. The nitrogen carrier
gas was removed via the sidearm of the ampule. Adjustment of
the nitrogen flow rate allowed the process to be monitored by
occasional pressure release at a manostat. Finally, the gas generator
was rapidly detached from the ampule which was sealed with the
Rotaflo barrel, degassed, and refilled with nitrogen while still at
-196 °C. Cautious warming to room temperature behind a safety
screen (calculated pressure is ca. 35 psi at room temperature), and
stirring at 70 °C for 6-12 h produced visible color changes. The
cooled suspensions were filtered, washed with pentane (2 × 20
mL), and dried under reduced pressure. Isolated yields were
essentially quantitative of bright red, red-purple, and purple solids,
respectively.
[RuBr2(η6-cymene)(PF2(NMe2)] (8). (Found: C, 28.05; H, 4.13;
N, 2.67%; C12H20F2Br2N1P1Ru calcd: C, 28.36; H, 3.97; N, 2.76%);
1H NMR (CDCl3): δ 1.24 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.32
(s, 3H, CH3-ring), 2.88 (dt, J(P-H) 11.2 Hz, J(F-H) 2.8 Hz, 6H,
PF2(NMe2), 2.98 (sept, J(HH) 7 Hz, 1H, CH(CH3)2), 5.53 (d, J(HH)
6.0 Hz, 2H, CH-ring), 5.69 (d, J(HH) 6.0 Hz, 2H, CH-ring); 31P{1H}
NMR (CDCl3): δ 136.7 (t, J(P-F) 1167 Hz; 13C {1H} NMR
(CDCl3): δ 112.35 (d, J(P-C) 3.5 Hz, C1-ring), 105.58 (d, J(P-C)
3.0 Hz, C4-ring), 90.02(d, J(P-C) 6.0 Hz, C2,6-ring), 89.63 (d,
J(P-C) 5.5 Hz, C3,5-ring), 37.34 (d, J(P-C) 6.5 Hz, PF2(NMe2),
[RuCl2(η6-cymene)PF3] (4). (Found: C, 30.34; H, 3.45%;
1
C10H14F3Cl2P1Ru calcd: C, 30.47; H, 3.58%); H NMR (CDCl3):
δ 1.27 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2,), 2.29 (s, 3H, CH3-ring),
2.88 (sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.72 (d, J(HH) 7.0 Hz,
2H, CH-ring), 5.85 (d, J(HH) 7.0 Hz, 2H, CH-ring); 31P{1H} NMR
(CDCl3): δ 107.4 (q, J(P-F) 1370 Hz); 13C {1H} NMR (CDCl3):
δ 112.81 (s, C1-ring), 108.78 (s, C4-ring), 91.34 (d, J(P-C) 8.0
Hz, C2,6-ring), 90.98 (d, J(P-C) 6.0 Hz, C3,5-ring), 31.17 (s,
CH(CH3)2), 22.03 (s, CH(CH3)2), 18.89 (s, CH3-ring); 19F{1H}
NMR (CDCl3): δ -25.4 (d, J(P-F) 1370 Hz).
31.09 (s, CH(CH3)2), 22.14 (s, CH(CH3)2), 19.04 (s, CH3-ring). 19
F
NMR (CDCl3): δ -43.26 (d sept, J(P-F) 1167 Hz, J(F-H) 3 Hz).
[RuI2(η6-cymene)(PF2(NMe2)] (9). (Found: C, 23.58; H, 3.03;
N, 2.27%; C12H20F2I2N1P1Ru calcd: C, 23.94; H, 3.35; N, 2.33%);
1H NMR (CDCl3): δ 1.26 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.49
(d, J(P-H) 0.9 Hz, 3H, CH3-ring), 2.89 (dt, J(P-H) 11.0 Hz, 6H,
J(F-H) 2.8 Hz, PF2(NMe2), 3.15 (sept, J(HH) 7 Hz, 1H,
CH(CH3)2), 5.53 (d, J(HH) 6.0 Hz, 2H, CH-ring), 5.71 (d, J(HH)
6.0 Hz, 2H, CH-ring); 31P{1H} NMR (CDCl3): δ 141.53 (t, J(P-F)
1146 Hz); 13C {1H} NMR (CDCl3): δ 114.53 (d, J(P-C) 5.0 Hz,
C1-ring), 106.87 (d, J(P-C) 4.5 Hz, C4-ring), 90.28(d, J(P-C)
5.0 Hz, C2,6-ring), 90.09 (d, J(P-C) 4.5 Hz, C3,5-ring), 38.25 (d,
J(P-C) 6.5 Hz, PF2(NMe2), 31.79 (s, CH(CH3)2), 22.60 (s,
CH(CH3)2), 20.08 (s, CH3-ring);. 19F NMR (CDCl3): δ -36.14 (d
sept, J(P-F) 1146 Hz, J(F-H) 2.8 Hz).
[RuBr2(η6-cymene)PF3] (5). (Found: C, 24.10; H, 2.89%;
1
C10H14F3Br2P1Ru calcd: C, 24.86; H, 2.92%); H NMR (CDCl3):
δ 1.26 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.38 (d, J(PH) 1.05 Hz,
3H, CH3-ring), 2.95 (sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.73 (d,
J(HH) 6.5 Hz, 2H, CH-ring), 5.85 (d, J(HH) 6.5 Hz, 2H, CH-ring);
31P{1H} NMR (CDCl3): δ 107.67 (q, J(P-F) 1346 Hz); 13C {1H}
NMR (CDCl3): δ 114.10 (d, J(P-C) 3.8 Hz, C1-ring), 108.97 (d,
J(P-C) 3.8 Hz, C4-ring), 91.44 (d, J(P-C) 7.7 Hz, C2,6-ring),
90.93 (d, J(P-C) 5.5 Hz, C3,5-ring), 31.46 (s, CH(CH3)2), 22.16
(70) Neels, A.; Stoeckli-Evans, H.; Plasseraud, L.; Fidalgo, E. G.; Suss-
Fink, G. Acta Crystallogr. C. 1999, 55, 2030–2032.
(71) Ngono, C. J.; Constantieux, T.; Buono, G. J. Organomet. Chem. 2002,
643, 237–246.
(72) Morse, J. G.; Cohn, K.; Rudolph, R. W.; Parry, R. W. Inorg. Synth.
1967, 10, 147–156.
(73) Reddy, G. S.; Schmutzler, R. Z. Naturforsch. B. 1965, 20, 104–109.
Preparation of [RuX2(η6-cymene)(PCl3)], X ) Cl (10), Br
(11), I (12). The appropriate dimer compound [RuX2(η6-cymene)]2
(0.3-0.4 g) was dissolved in dichloromethane (30 mL) and stirred
Inorganic Chemistry, Vol. 47, No. 20, 2008 9289

Boshaala et al.
with trichlorophosphine (3 mL, excess) for 24 h. The bright red
solution was concentrated (10 mL) and petroleum ether (40-60
°C) was added to produce a red precipitate. Crystallization was
completed at -30 °C overnight. Filtration and several washings
with light petroleum ether (2 × 20 mL) gave a microcrystalline
mass which was dried under reduced pressure. The isolated yields
of red (10), dark red (11), and purple (12) were 85, 75, and 70%,
respectively.
6.0 Hz, 2H, CH-ring); 31P{1H} NMR (CDCl3): δ 108.74 (s,
P(NMe2)3); 13C {1H} NMR (CDCl3): δ 112.28 (d, J(P-C) 10.0
Hz, C1-ring), 97.96 (s, C4-ring), 88.86 (d, J(P-C) 8.0 Hz, C2,6-
ring), 85.43 (s, C3,5-ring), 39.51 (d, J(P-C) 5 Hz, P(NMe2)3), 30.44
(s, CH(CH3)2), 27.30 (s, CH(CH3)2), 18.04 (s, CH3-ring). 13C{1H}-
1H correlations: (1.30, 27.30); (2.15, 18.04); (3.00, 30.44); (5.11,
88.86); (5.50, 85.43).
Preparation of [RuBr2(η6-cymene)(P(NMe2)3] (15). [RuBr2(η6-
cymene)]2 (0.3 g, 0.38 mmol) was dissolved in dichloromethane
(30 mL) and stirred with tris(dimethylamino)phosphine (3 mL, 16.5
mmol) for 24 h. The bright red solution was concentrated (10 mL)
and petroleum ether (40-60 °C) was added to produce a red
precipitate. Crystallization was completed at -30 °C overnight.
Filtration and several washings with light petroleum ether (2 × 20
mL) gave a dark red mass identified as [RuBr2(η6-cymene)(P-
(NMe2)3)], (0.29 g, 69%). (Found: C, 34.04; H, 5.64; N, 7.33%;
[RuCl2(η6-cymene)PCl3] (10). (Found: C, 27.58; H, 3.45%;
1
C10H14Cl5P1Ru calcd: C, 27.08; H, 3.18%); H NMR (CDCl3): δ
1.27 (d, J(HH) 7.0 Hz. 6H, CH(CH3)2), 2.24 (s, 3H, CH3-ring), 3.0
(sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.75 (s, 4H, CH-ring); 31P{1H}
NMR (CDCl3): δ 141.8 (s, PCl3); 13C {1H} NMR (CDCl3): δ 113.61
(s, C1-ring), 102.41 (s, C4-ring), 93.12 (d, J(P-C) 7.5 Hz, C2,6-
ring), 89.95 (d, J(P-C) 9.0 Hz, C3,5-ring), 30.84 (s, CH(CH3)2),
21.88 (s, CH(CH3)2), 18.28(s, CH3-ring).
1
[RuBr2(η6-cymene)PCl3] (11). (Found: C, 22.95; H, 2.45%;
C10H14Br2Cl3P1Ru calcd: C, 22.56; H, 2.65%); 1H NMR (CDCl3):
δ 1.28 (d, J(HH) 7.0 Hz. 6H, CH(CH3)2), 2.34 (s, 3H, CH3-ring),
3.14 (sept, J(HH) 7.0 Hz, 1H, CH(CH3)2), 5.71 (s, 4H, CH-ring);
31P{1H} NMR (CDCl3): δ 126.37 (s, PCl3); 13C {1H} NMR
(CDCl3): δ 115.31 (s, C1-ring), 102.88 (s, C4-ring), 93.46 (d,
J(P-C) 7.5 Hz, C2,6-ring), 89.98 (d, J(P-C) 9.5 Hz, C3,5-ring),
31.38 (s, CH(CH3)2), 22.04 (s, CH(CH3)2), 19.09(s, CH3-ring).
[RuI2(η6-cymene)PCl3] (12). (Found: C, 18.75; H, 2.05%;
C10H14Cl3P1I2Ru calcd: C, 19.17; H, 2.25%); 1H NMR (CDCl3): δ
1.29 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.14 (s, 3H, CH3-ring),
3.38 (sept, J(HH) 7.0 Hz 1H, CH(CH3)2), 5.71 (d, J(HH) 6.5 Hz,
2H, CH-ring), 5.74 (d, J(HH) 6.5 Hz, 2H, CH-ring); 31P{1H} NMR
(CDCl3): δ 107.0 (s, PCl3); 13C {1H} NMR (CDCl3): δ 117.74 (s,
C1-ring), 104.60 (s, C4-ring), 94.20 (d, J(P-C) 7.0 Hz, C2,6-ring),
90.79 (d, J(P-C) 9.5 Hz, C3,5-ring), 30.92 (s, CH(CH3)2), 22.48
(s, CH(CH3)2), 20.18(s, CH3-ring).
Preparation of [RuBr2(η6-cymene)PBr3] (13). [RuBr2(η6-
cymene)]2 (0.3 g, 0.38 mmol) was dissolved in dichloromethane
(30 mL) and stirred with tribromophosphine (3 mL, excess) for
24 h. The bright red solution was concentrated (10 mL) and
petroleum ether (40-60 °C) was added to produce a red precipitate.
Crystallization was completed at -30 °C overnight. Filtration and
several washings with light petroleum ether (2 × 20 mL) gave a
red mass identified as [RuBr2(η6-cymene)PBr3], (0.32 g, 64%).
(Found: C, 18.71; H, 2.05%; C10H14Br5P1Ru calcd: C, 18.04; H,
2.12%); 1H NMR (CDCl3): δ 1.29 (d, J(HH) 7.0 Hz, 6H,
CH(CH3)2), 2.34 (s, 3H, CH3-ring), 3.19 (sept, J(HH) 7.0 Hz, 1H,
CH(CH3)2), 5.56 (d, J(HH) 6.0 Hz, 2H, CH-ring), 5.71 (d, J(HH)
6.0 Hz, 2H, CH-ring); 31P{1H} NMR (CDCl3): δ 69.8 (s, PBr3);
13C {1H} NMR (CDCl3): δ 115.50 (s, C1-ring), 101.50 (s, C4-
ring), 94.16 (d, J(P-C) 7.0 Hz, C2,6-ring), 89.53 (d, J(P-C) 8.5
Hz, C3,5-ring), 31.53 (s, CH(CH3)2), 22.00 (s, CH(CH3)2), 18.66
(s, CH3-ring).
C16H32Br2N3P1Ru calcd: C, 34.42; H, 5.78; N, 7.53%); H NMR
(CDCl3): δ 1.27 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.14 (s, 3H,
CH3-ring), 2.66 (d, J(PH) 8.5 Hz, 18H, P(NMe2)3, 3.19 (m, H,
CH(CH3)2), 4.98 (d, J(HH) 6.0 Hz, 2H, CH-ring), 5.52 (d, J(HH)
6.0 Hz, 2H, CH-ring); 31P{1H} NMR (CDCl3): δ 108.22 (s,
P(NMe2)3); 13C {1H} NMR (CDCl3): δ 112.19 (d, J(P-C) 10.6
Hz, C1-ring), 98.74 (s, C4-ring), 89.85 (d, J(P-C) 5.5 Hz, C2,6-
ring), 83.67 (s, C3,5-ring), 39.34 (d, J(P-C) 5.0 Hz, P(NMe2)3),
30.07 (s, CH(CH3)2), 21.81 (s, CH(CH3)2), 17.44 (s, CH3-ring).
Preparation of [RuI2(η6-cymene)(P(NMe2)3] (16). [RuI2(η6-
cymene)]2 (0.3 g, 0.31 mmol) was dissolved in dichloromethane
(30 mL) and stirred with tris(dimethylamino)phosphine (3 mL, 16.5
mmol) for 24 h. The bright red solution was concentrated (ca. 10
mL), and petroleum ether (40-60 °C) was added; a red microc-
rystalline product formed in the refrigerator at -30 °C overnight.
Filtration and several washings with light petroleum ether (2 × 20
mL) gave a red mass identified as [RuI2(η6-cymene)(P(NMe2)3],
1
(0.34 g, 85%). H NMR (CDCl3): δ 1.25 (d, J(HH) 7.0 Hz, 6H,
CH(CH3)2), 2.15 (s, 3H, (CH3-ring), 2.65 (d, J(PH) 8.5 Hz, 18H,
P(NMe2)3), 2.8 (m, H, CH(CH3)2), 5.10 (d, J(HH) 6.0 Hz, 2H, CH-
ring), 5.80 (d, J(HH) 6.0 Hz, 2H, CH-ring); 31P{1H} NMR (CDCl3):
δ 109.48 (s, P(NMe2)3); 13C{1H} NMR [CDCl3}: δ 112.27 (d,
J(P-C) ) 12 Hz, C1-ring), 101.98 (s, C4-ring), 91.68 (d, J(P-C)
5 Hz, C2,6-ring), 85.05 (s, C3,5-H-ring), 40.84 (d, J(P-C) 5.0 Hz,
P(NMe2)3), 31.54 (s, (CH(Me)2), 22.94, (s, CH(CH3)2), 18.13 (s,
CH3-ring).
Computational Details. DFT calculations were based on the
single crystal X-ray structure of [RuBr2(η6-cymene)(PF3)] as a
starting point. The ADF 2005 (Amsterdam Density Functional74
)
program has been used to optimize the geometries. For these
optimizations, a spin-free relativistic Hamiltonian (the zeroth-
order regular approximation, or ZORA75,76) has been applied
along with the basis sets TZP (triple-ꢁ singly polarized) and
QZ4P (quadruple-ꢁ with 4 sets of polarization functions) of the
Preparation of [RuCl2(η6-cymene)(P(NMe2)3] (14). [RuCl2(η6-
cymene)]2 (0.3 g, 0.49 mmol) was dissolved in dichloromethane
(30 mL) and stirred with tris(dimethylamino)phosphine (3 mL, 16.5
mmol) for 24 h. The bright red solution was concentrated (10 mL)
and petroleum ether (40-60 °C) was added to produce a red
precipitate. Crystallization was completed at -30 °C overnight.
Filtration and several washings with light petroleum ether (2 × 20
mL) gave a red mass identified as [RuCl2(η6-cymene)(P(NMe2)3)],
(0.33 g, 72%). (Found: C, 40.63; H, 7.05; N, 8.74%;
(74) Baerends, E. J.; Autschbach, J.; Berces, A.; Bo, C.; Boerrigter, P. M.;
Cavallo, L.; Chong, D. P.; Deng, L.; Dickson, R. M.; Ellis, D. E.;
Fan, L.; Fischer, T. H.; Guerra, C. F.; van Gisbergen, S. J. A.;
Groeneveld, J. A.; Gritsenko, O. V.; Gruning, M.; Harris, F. E.; van
den Hoek, P.; Jacobsen, H.; van Kessel, G.; Kootstra, F.; van Lenthe,
E.; Osinga, V. P.; Patchkovskii, S.; Philipsen, P. H. T.; Post, D.; Pye,
C. C.; Ravenek, W.; Ros, P.; Schipper, P. R. T.; Schreckenbach, G.;
Snijders, J. G.; Sola, M.; Swart, M.; Swerhone, D.; Velde, G. t.;
Vernooijs, P.; Versluis, L.; Visser,O.; van Wezenbeek, E.; Wiesenek-
ker, G.; Wolff, S. K.; Woo, T. K.; Ziegler, T., Amsterdam Density
Functional program (ADF); Vrije Universiteit Amsterdam: Amster-
dam, The Netherlands, 2004; http://www.scm.com.
1
C16H32Cl2N3P1Ru calcd: C, 40.94; H, 6.87; N, 8.95%); H NMR
(75) Lenthe, E. v.; Baerends, E. J.; Snijders, J. G. J. Chem. Phys. 1993,
99, 4597–4610.
(76) Lenthe, E. v.; Ehlers, A.; Baerends, E. J. J. Chem. Phys. 1999, 110,
8943–8953.
(CDCl3): δ 1.30 (d, J(HH) 7.0 Hz, 6H, CH(CH3)2), 2.15 (s, 3H,
CH3-ring), 2.69 (d, J(PH) 8.5 Hz, 18H, P(NMe2)3), 3.0 (m, H,
CH(CH3)2), 5.11(d, J(HH) 6.0 Hz, 2H, CH-ring), 5.50 (d, J(HH)
9290 Inorganic Chemistry, Vol. 47, No. 20, 2008

Trihalophosphine Complexes of Ruthenium
(µB)
P(µ )hsr
(3)
ADF basis set library and the Becke 88-Perdew 86 non-hybrid
generalized gradient approximation (GGA) functional (BP).77,78
Subsequent calculations of the spin-spin coupling constants
were performed with the Gaussian 0379 (G03) and the ADF
programs based on the optimized structures. In the Gaussian
calculations we applied the B3LYP77 hybrid functional along
with a scalar relativistic effective core potential (LANL2DZ)
for the metal. For Ru, F, C, H, P, Cl, Br, and I, we have used
the basis sets LANL2DZ,80 IGLO-III, 6-311G(d), 6-311G(d),
IGLO-III + 6-311G** polarization functions, 6-311G(d),
6-311G(d), and DZVP,81 respectively. It has been shown in
the literature that the IGLO basis allows one to obtain reliable
spin-spin coupling constants.82 For reasons of computational
cost we have used this large basis only for P and F and applied
smaller basis sets for the other atoms. The main purpose of these
calculations was to check that inclusion of exact exchange in
the functional does not have an effect on the computed trends
for the halide substitutions in the complexes. For the ZORA
calculations of spin-spin coupling with ADF at the spin-free
(scalar, ZSC) and at the spin-orbit ZORA (ZSO) level of theory
we have employed the spin-spin coupling program of the ADF
package (which is described in detail elsewhere 45,83) using the
BP functional and the TZP and QZ4P basis sets.
A
K(x,y)(A, B) )
∑∑
rs
r
s
(µA
)
Here, Prs
is the density matrix perturbed by the magnetic
(µB
)
moment of nucleus A, and hrs are the matrix elements due to
the perturbation by the other nucleus. A “fragment orbital”
analysis was performed using eq 3 which decomposes the
calculated K into contributions from pairs r,s of localized
fragment orbitals. Details can be found elsewhere.56,58,62 Further,
an analysis using orbitals determined by the NBO 5.0 program84
was implemented for relativistic ZORA methods, similar to the
“natural shielding analysis” originally developed within a
nonrelativistic framework by Bohmann et al.57 This analysis uses
eq 3 as a starting point and performs a series of transformation
from the AO basis via a basis of “natural bond orbitals” (NBOs)
to a basis of natural localized molecular orbitals (NLMOs) as
determined by the NBO program. An interface between ADF
and NBO 5.0 which has facilitated the implementation has been
developed by one of us (J.A.). This new analysis feature was
originally developed for the present work using a scalar
relativistic theoretical framework (as applied here), which has
not previously been published elsewhere. The NLMO/NBO
analysis of J-coupling was subsequently extended to ZORA
spin-orbit computations by one of the authors. The more general
spin-orbit case has been described in detail, and we refer the
reader to this paper for details regarding the implementation and
the theoretical formalism as well as some applications to validate
the method.85 A corresponding analysis for chemical shifts was
also developed recently by us,86 as well as analyses of first and
second hyperpolarizabilities.87,88 The NBO program yields a set
of NLMOs, to each of which the NBO algorithms assign a
strongly localized parent NBO. In the present as well as our
other analysis papers62,86-88 we noted that in delocalized
electronic structures (often in metal complexes) an automatic
NBO generation does not always yield intuitive results (e.g.,
delocalized bond NLMOs are obtained with a low-occupancy
parent lone-pair NBO instead of a bonding NBO). The overall
NLMO analysis is generally not much affected by this, but the
decomposition into localized and delocalization terms which
refers to the NBO basis can be altered. For the complexes studied
here, the ADF computations with their rather flexible basis sets
initially did not yield the desired set of P-F bonding NBOs.
However, the application of the $CHOOSE keyword in the NBO
5.0 computations provided a workaround, and the set of P-F
bonding NBOs and the Ru-P NBO were obtained. The
subsequent NLMO analysis of J-coupling has been based on
this set of NLMOs/NBOs, although we point out that the
qualitative aspects of the analysis do not change if the $CHOOSE
keyword is not applied (in this case the nature of the NLMOs is
easily determined by orbital plots similar to those in Figure 2).
Generally, computations determine the so-called reduced indirect
spin-spin coupling constants K for a pair of nuclei, A and B, which
are then converted to J-coupling constants by
h
4π2
J(A, B) )
γAγBK(A,B)
(1)
Here, h is Planck’s constant, and γA and γB are the magnetogyric
ratios for atoms A and B. For 31P-19F couplings, this leads to a
conversion factor of 4.582 from K in 1019 T2/J to J in units of Hz.
MO contributions58 to the spin-spin coupling were obtained
from the equation for the K-tensor elements
ˆ(µ )
ˆ(µ )
y i
occ unocc
A
B
φ |h |φ φ |h |φ
〈
j 〉 〈
〉
+
i
x
j
K(x,y)(A, B) ) 2 Re
∑ ∑
εi - εj
i
j
occ
ˆ(µ ,µ )
φ |h
A
x,y
B
|φ (2)
〈
〉
∑
i
i
i
The µA and µB superscripts indicate the relevant first and second
order perturbation operators with respect to the magnetic moment
of nucleus A and B, respectively. One of the first-order operators
also contains the perturbation of the molecule’s Kohn-Sham
potential which is determined self-consistently in the calculations.
The ε’s are the orbital energies, and the φ’s the occupied and
unoccupied canonical Kohn-Sham orbitals. The second term in
eq 2 is the diamagnetic term which was found to be negligible for
the coupling constants in the present work. The first term comprises
the sum of the paramagnetic, the spin-dipole (SD), the Fermi-contact
(FC), and their cross terms and can be written in the AO or another
fragment orbital basis as
(77) Becke, A. D. Phys. ReV. A. 1988, 38, 3098–3100.
(78) Perdew, J. P. Phys. ReV. B. 1986, 33, 8822–8824.
(79) Frisch, M. J. et al. Gaussian 03, Revision B.04; Gaussian, Inc.:
Wallingford, CT, 2004.
(80) Wadt, W. R.; Hay, P. J. J. Chem. Phys. 1985, 82, 284–298.
(81) Godbout, N.; Salahub, D. R.; Andzelm, J.; Wimmer, E. Can. J. Chem.
1992, 70, 560.
(82) Sychrovsky, V.; Grafenstein, J.; Cremer, D. J. Chem. Phys. 2000, 113,
3530–3547.
(83) Autschbach, J.; Ziegler, T. J. Chem. Phys. 2000, 113, 936–947.
(84) Glendening, E. D.; Badenhoop, J. K.; Reed, A. E.; Carpenter, J. E.;
Bohmann, J. A.; Morales, C. M.; Weinhold, F. NBO 5.0; Theoretical
Chemistry Institute, University of Wisconsin: Madison, WI, 2001;
http://www.chem.wisc.edu/simnbo5.
(85) Autschbach, J. J. Chem. Phys. 2007, 127, 124106.
(86) Autschbach, J. J. Chem. Phys. 2008, 128, 164112.
(87) Ye, A.; Autschbach, J. J. Chem. Phys. 2006, 125, 234101.
(88) Ye, A.; Patchovskii, S.; Autschbach, J. J. Chem. Phys. 2007, 127,
074104.
Inorganic Chemistry, Vol. 47, No. 20, 2008 9291

Boshaala et al.
Acknowledgment. We thank Johnson-Matthey Chemi-
cals Ltd. for a generous loan of ruthenium trichloride and
acknowledge the use of the EPSRC Chemical Database
Service at Daresbury.89 Special thanks to the University
of Salford SMT for making travel funds available under
the DIASPORA initiative. We thank the Center for
Computational Research (CCR) at the University at
Buffalo for support. J.A. acknowledges the CAREER
program of the National Science Foundation (Grant CHE-
0447321) as well as the Petroleum Research Fund for
financial support of this research. J.A. and S.Z. thank two
of the reviewers for helpful comments and suggestions.
Supporting Information Available: Crystallographic data in
CIF format. This material is available free of charge via the Internet
at http://pubs.acs.org.
(89) Fletcher, D. A.; McMeeking, R. F.; Parkin, D. J. Chem. Inf. Comput.
Sci. 1996, 36, 746–749.
IC800611H
9292 Inorganic Chemistry, Vol. 47, No. 20, 2008