Synthesis, structure, and reactivity of four-, five-, and six-coordinate ruthenium carbyne complexes

Article abstract of DOI:10.1021/om061192v

Square-planar carbyne complexes of the form Ru(≡CR)(PCy ₃)₂X (X = F, Cl, Br, I, O₃SCF₃) are prepared by net dehydrohalogenation of the Grubbs catalysts Ru(≡CHR) (PCy₃)₂Cl₂ followed by substitution of the chloride ligand (when X ≠ Cl). The dehydrohalogenation can be effected in one step (R = n-Bu, Ph, p-C₆H₄Me) by Ge(CH[SiMe ₃]₂)₂ or in two steps via treatment with excess aryloxide such as NaO-p-C₆H₄-t-Bu followed by SnCl ₂. The latter route gives greater yields but is more restricted in scope. Addition of HCl (1 equiv) to Ru(=CR)(PCy₃)₂X (X = Cl, Br, I) affords Ru(=CHR)(PCy₃)₂ClX; those with mixed halide ligand sets undergo rapid halide exchange in solution. Upon treatment with the appropriate oxidant, each Ru(=C-p-C₆H₄Me) (PCy₃)₂X complex undergoes two-electron oxidation. Oxidation of Ru(=C-p-C₆H₄Me)(PCy₃)₂X (X = F, Cl, Br, I) by XeF₂, C₂Cl₆, Br ₂, and, respectively, yields either six-coordinate bis-phosphine complexes Ru(=C-p-C₆H₄Me)(PCy₃) ₂X₃ (X = F, Cl) or square-pyramidal mono-phosphine complexes Ru(≡C-p-C₆H₄Me)(PCy₃)X ₃ (X = Br, I) depending on the size of the halide ligands. Cationic square-pyramidal complexes of the form [Ru(=C-p-C₆H ₄Me)(PCy₃)₂X₂]⁺ (X = Cl, I) can be prepared from Ru(≡C-p-C₆H₄Me)(PCy ₃)₂Cl₃ by chloride abstraction using [Ph ₃C]BF₄ and from Ru(≡C-p-C₆H ₄-Me)(PCy₃)X₃ by addition of PCy₃. Hydride addition to Ru(≡C-p-C₆H₄Me)(PCy ₃)₂Cl₃ yields the carbene complex Ru(=CHR)(PCy₃)₂Cl₂, whereas fluoride addition affords the carbyne complex Ru(≡C-p-C₆H₄-Me(PCy ₃)₂Cl₂F, results with important implications for metathesis of vinyl fluorides. X-ray structures of Ru(≡C-p-C ₆H₄Me)(PCy₃)₂X₂F (X = F, Cl), [Ru(≡C-p-C₆H₄Me)PCy₃) ₂Cl₂]BF₄, and Ru(≡C-p-C₆H ₄-Me)(PCy₃)I₃ reveal short Ru≡C bonds in the 1.670(5)-1.714(3) A range; when two PCy₃ ligands are present, they are mutually trans. The benzylidyne ligands occupy the apical sites in the two square-pyramidal complexes. Of the five- and six-coordinate complexes, only the two fluoride-containing complexes Ru(≡C-p-C ₆H₄Me)(PCy₃)₂X₂F (X = F, Cl) display reactivity toward alkynes, serving as alkyne dimerization catalysts.

Full text of DOI:10.1021/om061192v

1912
Organometallics 2007, 26, 1912-1923
Synthesis, Structure, and Reactivity of Four-, Five-, and
Six-Coordinate Ruthenium Carbyne Complexes
†
Stephen R. Caskey,† Michael H. Stewart,† Yi Joon Ahn,† Marc J. A. Johnson*,
Jesse L. C. Rowsell,‡ and Jeff W. Kampf†
Department of Chemistry, UniVersity of Michigan, 930 N. UniVersity AVenue, Ann Arbor, Michigan
48109-1055, and Department of Chemistry & Biochemistry, Oberlin College, 119 Woodland Street,
Oberlin, Ohio 44074-1097
ReceiVed December 31, 2006
Square-planar carbyne complexes of the form Ru(tCR)(PCy3)2X (X ) F, Cl, Br, I, O3SCF3) are prepared
by net dehydrohalogenation of the Grubbs catalysts Ru(dCHR)(PCy3)2Cl2 followed by substitution of
the chloride ligand (when X * Cl). The dehydrohalogenation can be effected in one step (R ) n-Bu, Ph,
p-C6H4Me) by Ge(CH[SiMe3]2)2 or in two steps via treatment with excess aryloxide such as NaO-p-
C6H4-t-Bu followed by SnCl2. The latter route gives greater yields but is more restricted in scope. Addition
of HCl (1 equiv) to Ru(tCR)(PCy3)2X (X ) Cl, Br, I) affords Ru(dCHR)(PCy3)2ClX; those with mixed
halide ligand sets undergo rapid halide exchange in solution. Upon treatment with the appropriate oxidant,
each Ru(tC-p-C6H4Me)(PCy3)2X complex undergoes two-electron oxidation. Oxidation of Ru(tC-p-
C6H4Me)(PCy3)2X (X ) F, Cl, Br, I) by XeF2, C2Cl6, Br2, and I2, respectively, yields either six-coordinate
bis-phosphine complexes Ru(tC-p-C6H4Me)(PCy3)2X3 (X ) F, Cl) or square-pyramidal mono-phosphine
complexes Ru(tC-p-C6H4Me)(PCy3)X3 (X ) Br, I) depending on the size of the halide ligands. Cationic
square-pyramidal complexes of the form [Ru(tC-p-C6H4Me)(PCy3)2X2]+ (X ) Cl, I) can be prepared
from Ru(tC-p-C6H4Me)(PCy3)2Cl3 by chloride abstraction using [Ph3C]BF4 and from Ru(tC-p-C6H4-
Me)(PCy3)X3 by addition of PCy3. Hydride addition to Ru(tC-p-C6H4Me)(PCy3)2Cl3 yields the carbene
complex Ru(dCHR)(PCy3)2Cl2, whereas fluoride addition affords the carbyne complex Ru(tC-p-C6H4-
Me)(PCy3)2Cl2F, results with important implications for metathesis of vinyl fluorides. X-ray structures
of Ru(tC-p-C6H4Me)(PCy3)2X2F (X ) F, Cl), [Ru(tC-p-C6H4Me)(PCy3)2Cl2]BF4, and Ru(tC-p-C6H4-
Me)(PCy3)I3 reveal short RutC bonds in the 1.670(5)-1.714(3) Å range; when two PCy3 ligands are
present, they are mutually trans. The benzylidyne ligands occupy the apical sites in the two square-
pyramidal complexes. Of the five- and six-coordinate complexes, only the two fluoride-containing
complexes Ru(tC-p-C6H4Me)(PCy3)2X2F (X ) F, Cl) display reactivity toward alkynes, serving as alkyne
dimerization catalysts.
alkyne metathesis catalysis remains restricted to complexes of
Mo, W, and Re.1 The ruthenium-carbyne complexes that most
closely resemble the Grubbs catalysts exemplified by
Ru(CHPh)(L)(PCy3)Cl2 (Chart 1: L ) PCy3 [1], H2IMes [2];
H2IMes ) 4,5-dihydro-1,3-bis(mesityl)imidazolin-2-ylidene) are
the cationic square-pyramidal species such as [Ru(CCH2R′)(PR3)2-
Cl2]+ (R ) Cy [3a, 3b], i-Pr [4a, 4b]; R′ ) Ph [3a, 4a], t-Bu
[3b, 4b]), which Werner and co-workers prepared via proto-
nation of the corresponding vinylidene complexes.12 Similarly,
protonation of allenylidene complexes can lead to alkenylcar-
byne complexes.15-19 Even these complexes, however, do not
Introduction
The number of ruthenium-carbene complexes available as
a result of ongoing research into Ru-catalyzed olefin metathesis
is large.1 In spite of mechanistic homology between olefin
metathesis and alkyne metathesis,2-7 only a very few ruthenium-
carbyne complexes have been reported,8-14 and none of these
are found to catalyze alkyne metathesis. Thus, homogeneous
* Corresponding author. Fax: (734) 647-4865. E-mail: mjaj@umich.edu.
† University of Michigan.
‡ Oberlin College.
(1) Grubbs, R. H. Handbook of Metathesis; Wiley-VCH: Weinheim,
2003; Vols. 1-3.
(2) Fomine, S.; Vargas, S. M.; Tlenkopatchev, M. A. Organometallics
2003, 22, 93.
(12) Gonza´lez-Herrero, P.; Weberndo¨rfer, B.; Ilg, K.; Wolf, J.; Werner,
H. Organometallics 2001, 20, 3672.
(3) Cavallo, L. J. Am. Chem. Soc. 2002, 124, 8965.
(4) Sanford, M. S.; Love, J. A.; Grubbs, R. H. J. Am. Chem. Soc. 2001,
123, 6543.
(5) Zhu, J.; Jia, G.; Lin, Z. Organometallics 2006, 25, 1812.
(6) Woo, T.; Folga, E.; Ziegler, T. Organometallics 1993, 12, 1289.
(7) Freudenberger, J. H.; Schrock, R. R.; Churchill, M. R.; Rheingold,
A. L.; Ziller, J. W. Organometallics 1984, 3, 1563.
(8) Gallop, M. A.; Roper, W. R. AdV. Organomet. Chem. 1986, 25, 121.
(9) Coalter, J. N.; Bollinger, J. C.; Eisenstein, O.; Caulton, K. G. New J.
Chem. 2000, 24, 925.
(13) Amoroso, D.; Snelgrove, J. L.; Conrad, J. C.; Drouin, S. D.; Yap,
G. P. A.; Fogg, D. E. AdV. Synth. Catal. 2002, 344, 757.
(14) Conrad, J. C.; Amoroso, D.; Czechura, P.; Yap, G. P. A.; Fogg, D.
E. Organometallics 2003, 22, 3634.
(15) Castarlenas, R.; Vovard, C.; Fischmeister, C.; Dixneuf, P. H. J. Am.
Chem. Soc. 2006, 128, 4079.
(16) Cadierno, V.; D´ıez, J.; Garc´ıa-Garrido, S. E.; Gimeno, J. Organo-
metallics 2005, 24, 3111.
(17) Rigaut, S.; Touchard, D.; Dixneuf, P. H. Organometallics 2003,
22, 3980.
(10) Sanford, M. S.; Henling, L. M.; Day, M. W.; Grubbs, R. H. Angew.
Chem., Int. Ed. 2000, 39, 3451.
(11) Gonza´lez-Herrero, P.; Weberndo¨rfer, B.; Ilg, K.; Wolf, J.; Werner,
H. Angew. Chem., Int. Ed. 2000, 39, 3266.
(18) Bustelo, E.; Jime´nez-Tenorio, M.; Mereiter, K.; Puerta, M. C.;
Valerga, P. Organometallics 2002, 21, 1903.
(19) Jung, S. F.; Brandt, C. D.; Werner, H. New J. Chem. 2001, 25,
1101.
10.1021/om061192v CCC: $37.00 © 2007 American Chemical Society
Publication on Web 03/17/2007

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1913
Chart 1. Numbered Compounds
Scheme 1. Synthesis of Square-Planar Mono-chloride
Benzylidyne Complex
complexes for structural and reactivity studies, particularly in
catalytic reactions involving alkyne substrates. Some of these
results have been communicated.24
Results and Discussion
It is tempting to suggest that the conspicuous absence of Ru-
(CHPh)(PCy3)2F2 (5) from the family of “first-generation”
Grubbs catalysts Ru(CHPh)(PCy3)2X2 (X ) Cl, Br, I) is due to
instability of 5 with respect to HF elimination and formation
of Ru(CPh)(PCy3)2F. Indeed, we find that reaction of Ru(CH-
p-C6H4Me)(PCy3)2Cl2 (6)25 with CsF in an attempt to prepare
Ru(CH-p-C6H4Me)(PCy3)2F2 (7) affords a mixture of products
that contains both Ru(C-p-C6H4Me)(PCy3)2Cl (8) and Ru(C-p-
C6H4Me)(PCy3)2F (9). Here we have used the p-tolyl substituent
for convenience of monitoring by 1H NMR spectroscopy
compared to 1 by virtue of a simplified aryl region and
diagnostic Me resonance. Use of [n-Bu4N]F‚3H2O instead of
CsF gives rise to a brown solution in which free PCy3 is the
only phosphorus-containing species observable by 31P NMR
spectroscopy. On the basis of these findings, we set out to
examine the synthesis and reactivity of ruthenium-benzylidyne
complexes, with special attention given to complexes that also
contain one or more fluoride ligands.
catalyze alkyne metathesis, possibly because they are readily
deprotonated to afford reactive 14-electron vinylidene com-
plexes.12
Low-Valent Carbyne Complexes by Elimination from the
Carbene Complexes. As previously communicated,24 complex
8, which is dark blue-green in the solid state and in solution,
can be prepared rationally in 41.4% isolated yield via direct
Following Fischer’s initial report in 1973, several synthetic
routes to compounds that contain metal-carbon triple bonds
have been developed.8,20-22 Several years ago, Caulton disclosed
the unexpected formation of square-planar Ru-carbyne com-
plexes Ru(CPh)(PR3)2(OPh) (R ) i-Pr, Cy) by treatment of Ru-
(CHPh)(PR3)2Cl2 with excess NaOPh.9 Fogg similarly prepared
Ru(CPh)(PCy3)2(OC6F5) from 1 by reaction with TlOC6F5,14
which led to the suggestion that product selectivity is driven
by steric interactions at an intermediate stage and that phenoxide
basicity was extraneous to the reaction,14 given that similar
treatment of 1 with KOC(CX3)3 (X ) H, F) yields the four-
coordinate carbene complexes Ru(CHPh)(PCy3)(OC(CX3)3)2
rather than the carbyne products of HOC(CX3)3 elimination.9,10
Likewise, an admixture of 2 equiv of TlOC6F5 to a solution of
Ru(CHPh)(IMes)(py)2Cl2 (py ) pyridine; IMes ) N,N′-bis-
(mesityl)imidazol-2-ylidene23) affords Ru(CHPh)(IMes)(py)-
(OC6F5)2 cleanly.14 We decided to harness the elimination route
in order to prepare a number of ruthenium benzylidyne
26
reaction of 6 with Ge(CH[SiMe3]2)2 (10). In addition to
benzylidyne complexes such as 8, the germylene 10 also affords
with equal facility carbyne complexes such as Ru(C-n-Bu)-
(PCy3)2Cl by dehydrochlorination of Ru(CH-n-Bu)(PCy3)2Cl2;
however, Ru(CH2)(PCy3)2Cl225,27 does not react with 10 under
the conditions attempted, but instead undergoes only the slow
decomposition characteristic of Ru(CH2)(PCy3)2Cl2 in solution
28
(Scheme 1). Unlike 10, the amidogermylene Ge(N[SiMe3]2)2
fails to convert 6 into 8 in appreciable yield. The dialkylstan-
nylene Sn(CH[SiMe3]2)2 (11)26 does react with 6, but several
products are formed due to the fact that 8 itself reacts with 11.
Accordingly, when 6 is treated with 3 equiv of 11, free PCy3 is
(24) Caskey, S. R.; Stewart, M. H.; Ahn, Y. J.; Johnson, M. J. A.; Kampf,
J. W. Organometallics 2005, 24, 6074.
(25) Schwab, P.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1996,
118, 100.
(26) Fjeldberg, T.; Haaland, A.; Schilling, B. E. R.; Lappert, M. F.;
Thorne, A. J. J. Chem. Soc., Dalton Trans. 1986, 1551.
(27) Pietraszuk, C.; Marciniec, B.; Fischer, H. Organometallics 2000,
19, 913.
(20) Fischer, H.; Hofmann, P.; Kreissl, F. R.; Schrock, R. R.; Schubert,
U.; Weiss, K. Carbyne Complexes; VCH Publishers: New York, 1988; p
235.
(21) Engel, P. F.; Pfeffer, M. Chem. ReV. 1995, 95, 2281.
(22) Schrock, R. R. Chem. ReV. 2002, 102, 145.
(23) Arduengo, A. J.; Dias, H. V. R.; Harlow, R. L.; Kline, M. J. Am.
Chem. Soc. 1992, 114, 5530.
(28) Gynane, M. J. S.; Harris, D. H.; Lappert, M. F.; Power, P. P.; Rivie`re,
P.; Rivie`re-Baudet, M. J. Chem. Soc., Dalton Trans. 1977, 2004.

1914 Organometallics, Vol. 26, No. 8, 2007
Caskey et al.
Scheme 3. Treatment of Planar Complexes with HCl
Scheme 2. Synthesis of Monohalide and Pseudohalide
Complexes
the only phosphorus-containing species observable by 31P NMR
spectroscopy after 40 min. Reaction of 6 with 1 equiv of 11
yields a mixture that contains 6, 8, and free PCy3 in a 54:15:31
integration ratio after 16 h. Thus, 10 is the most convenient
reagent we have found for single-step dehydrochlorination of
6 and its analogues.
Scheme 4. Two-Electron Oxidation of Planar Monohalide
Complexes
Roper has reported six closely related ruthenium complexes
that contain one additional ligand. In an unusual reaction,
treatment of Ru(dCCl2)(CO)(PPh3)2Cl2 with 2 equiv of ArLi
(Ar ) Ph, 4-C6H4OMe, 1-naphthyl) at low temperature in
tetrahydrofuran affords the neutral complexes Ru(tCAr)(CO)-
(PPh3)2Cl along with 1 equiv of ArCl. Upon reaction with CO,
chloride is displaced, affording the cationic complexes
[Ru(tCAr)(CO)2(PPh3)2]+.29,30 The osmium analogues behave
similarly.29,30
Scheme 5. Formation of a Cationic Bisphosphine
Benzylidyne Complex
Convenient Two-Step Synthesis of 8. Although the reaction
of 6 with 10 affords 8 rapidly and cleanly, for large-scale
reactions we find that a two-step procedure yields 8 in greater
overall yield more economically and without the need to
synthesize and purify 10 (Scheme 1). Dissolution of a solid
mixture of 6 and at least 3 equiv NaO-p-C6H4-t-Bu in a 4:1
(v/v) toluene-THF mixture affords a forest green analogue of
Caulton’s Ru(CPh)(PCy3)2(OPh), Ru(C-p-C6H4Me)(PCy3)2(O-
p-C6H4-t-Bu) (12), in 66% isolated yield on a multigram scale.
A 4:1 solvent ratio by volume appears optimal. Some THF is
required in order to obtain a reasonable reaction rate, but too
much THF results in the formation of undesirable side products.
We prefer to use NaO-p-C6H4-t-Bu instead of NaOPh for
convenience of handling and simplification of 1H NMR spectra.
Additionally, as communicated previously, reaction of 1 with
at least 3 equiv of NaO-p-C6H4-t-Bu affords square-planar Ru-
(CPh)(PCy3)2(O-p-C6H4-t-Bu) (13), which, unlike Ru(CPh)(P-
i-Pr3)2(OPh) and Ru(CPh)(PCy3)2(OC6F5), does not suffer from
crystallographic disorder of the benzylidyne and aryloxide
ligands, thus permitting precise determination of the RutC bond
length (1.7178(16) Å).24 Addition of 12 dissolved in THF to a
THF solution of 0.6 equiv of SnCl2 affords 8 cleanly in 87%
yield on a multigram scale; order of addition is important in
order to avoid re-formation of 6. In this way, we routinely obtain
several grams of analytically pure 8 in 58% overall yield from
6 in two simple steps.
Scheme 6. Formation of a Triiodide Bisphosphine
Benzylidyne
complexes Ru(C-p-C6H4Me)(PCy3)2X (X ) Br [14], I [15]) are
prepared from 8 by reaction with an excess of a suitable alkali
halide. Treatment of 8 with 10 equiv of LiBr in 4:1 (v/v)
toluene-THF affords blue-green 14 rapidly in 71% isolated
yield; addition of 10 equiv of NaI to a THF solution of 8 results
in its conversion to gray-green 15, which can be isolated in
68% yield. The fluoro complex Ru(C-p-C6H4Me)(PCy3)2F (9)
can be prepared in several ways. Reaction of 8 with excess
anhydrous CsF in THF is slow and proceeds only to ap-
proximately 50% conversion over 2 weeks at 22 °C. Similarly,
SnF2 converts 12 into 9 only slowly in THF. Much more rapid
is the reaction of 8 with [S(NMe2)3[SiF2Me3] (TAS-F). How-
ever, the expense of this reagent limits its utility. An excess of
CsF reacts with 8 and 1.2 equiv of 18-crown-6 in 3:2 (v/v)
Substitution of the Chloride Ligand in 8. Complex 8 is an
excellent precursor to a family of complexes of the form Ru-
(C-p-C6H4Me)(PCy3)2X (Scheme 2). Unsurprisingly, treatment
of 8 with NaO-p-C6H4-t-Bu in 9:1 (v/v) toluene-THF regener-
ates 12 cleanly in 59% isolated yield. The bromo and iodo
(29) Roper, W. R. In Transition Metal Carbyne Complexes, Kreissl, F.
R., Ed.; Kluwer: Boston, 1993; Vol. 392, p 155.
(30) Baker, L. J.; Clark, G. R.; Rickard, C. E. F.; Roper, W. R.;
Woodgate, S. D.; Wright, L. J. J. Organomet. Chem. 1998, 551, 247.

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1915
Table 1. Crystallographic Data for Complexes 19, 22, 25, and 26
19
22
25
26
formula
fw
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C45H74Cl2F3P2Ru
905.95
monoclinic
P21/m
9.5265(18)
23.609(5)
11.124(2)
90
113.372(12)
90
2296.6(8)
2
C26H40I3PRu
865.32
orthorhombic
Pbca
17.267(2)
17.974(2)
18.631(3)
90
C93H156B2Cl14F8P4Ru2
2270.12
monoclinic
P21/c
11.626(4)
32.847(12)
28.253(10)
90
99.152(6)
90
10652(7)
4
C46H73Cl6D4FP2Ru
1028.81
monoclinic
P21/m
13.721(3)
17.724(4)
20.827(5)
90
92.642(4)
90
5059.6(19)
4
90
90
5782.3(14)
8
Z
radiation (KR, Å)
0.71073
123(2)
1.310
0.569
958
0.0530
0.0969
1.030
0.71073
123(2)
1.988
3.814
3312
0.0271
0.0807
1.288
0.71073
108(2)
1.416
0.751
4728
0.0590
0.1310
1.160
0.71073
123(2)
1.351
0.724
2152
0.0402
0.0816
1.010
T (K)
D
µ
calcd (Mg m-3
)
calcd (mm-1
)
F000
R1
wR2
GOF
DME-THF to effect quantitative formation of 9 over 48 h; 9
can then be isolated in 40% yield after two recrystallizations.
However, 9 is most conveniently prepared by reaction of
[n-Bu4N]F‚3H2O with 8 over 3 h in THF; following this
procedure 9 can be isolated in 81% yield. In THF, blue-green
9 gives rise to a doublet at δ 47.1 (2JFP ) 37 Hz) in the 31P
NMR spectrum due to coupling to one F nucleus, indicating
that a single Ru-F bond persists on the NMR time scale. The
19F NMR spectrum exhibits a triplet at δ -189.6 with the same
coupling constant, thus establishing the presence of two
equivalent 31P nuclei. Additionally, the p-methylbenzylidyne
R-C nucleus evinces coupling to a single 19F nucleus and two
equivalent 31P nuclei (dt at δ 247.00 in the 13C{1H} NMR
produce Ru(CH-p-C6H4Me)(PCy3)2ClF (18), but instead affords
6 and starting complex 9. Likewise, treatment of 8 with Et3N‚
3HF fails to yield 7 or 18. Accordingly, we suggest that both 7
and 18 are unstable with respect to HF elimination under the
conditions we have used and that this fact accounts for their
conspicuous absence from the family of first-generation Grubbs
catalysts.
Two-Electron Oxidation of Planar Carbynes. With the
planar carbyne complexes Ru(C-p-C6H4Me)(PCy3)2X (X ) F,
Cl, Br, I, OTf; 9, 8, 14, 15, 16, respectively) in hand, we next
examined their oxidation in order to obtain analogues of 3a and
3b that due to a lack of â-H atoms are not subject to conversion
into vinylidene compounds by deprotonation. As shown in
Scheme 4, all the halide complexes undergo clean two-electron
oxidation to trihalide complexes. With the smaller halides, six-
coordinate bis-phosphine complexes trans,mer-Ru(C-p-C6H4-
Me)(PCy3)2X3 (X ) F, Cl: 19, 20, respectively) are formed
preferentially. For oxidation of 9, 1.35 equiv of XeF2 in C6H6
is most effective, producing 19 in 45% isolated yield. AgF in
THF is also effective, affording 19 in 16% yield. The NMR
spectra of 19 are highly characteristic. The 31P{1H} NMR
spectrum in CD2Cl2 shows a doublet of triplets at δ 25.3 ppm
(2JPF ) 34 Hz, 2JPF ) 9.8 Hz) with coupling to two inequivalent
fluorine environments, while the 19F NMR provides two
signals: a triplet of triplets at δ -190.96 ppm (2JFF ) 120 Hz,
2JPF ) 32 Hz) for the fluoride trans to the carbyne unit and a
broad doublet at δ -419.50 ppm (2JFF ) 120 Hz) for the
mutually trans fluorides; coupling to the phosphine ligands was
unresolved in this resonance. Complex 20 is isolated in 52%
yield following reaction of 8 with C2Cl6. Although 19 is stable
in solution for some time, 20 undergoes relatively rapid
decomposition in solution. In contrast, five-coordinate square-
pyramidal compounds Ru(C-p-C6H4Me)(PCy3)X3 (X ) Br, I:
21, 22, respectively) are formed preferentially upon oxidation
of Ru(C-p-C6H4Me)(PCy3)2X with the corresponding halogen
in hydrocarbon solution. Both 21 and 22 are stable for days in
solution at 28 °C. In the syntheses of 21 and 22, it was most
convenient to use the appropriate halogen as the oxidant.
Although 22 was isolated in 78% yield, 21 remains contaminated
with [BrPCy3]Br, which we have been unable to remove
completely.
2
2
spectrum; JCF ) 134.0 Hz, JCP ) 18.9 Hz). We therefore
propose that 9 adopts a square-planar geometry in solution, just
as 13 does in the solid state,24 a geometry that is consistent
with a formal 16-electron count at Ru, ignoring any π-contribu-
tion from F.
Addition of 1 equiv of Me3SiOTf (Tf ) CF3SO2) to a solution
of 8 in C6D6 causes precipitation of a blue-green powder that
analyzes as Ru(C-p-C6H4Me)(PCy3)2OTf (16). This compound
is unstable in solution. However, upon dissolution in THF it
forms a blue-green solution that exhibits single resonances at δ
44.0 and -77.5 in the 31P and 19F NMR spectra, respectively,
prior to its decomposition into as-yet-uncharacterized products.
Reactions of Square-Planar Carbynes with HX. Formation
of 8 from 6 is a net dehydrochlorination reaction. The reverse
transformation is obtained rapidly and quantitatively by the
simple expedient of treating 8 with ethereal HCl. Even at very
low temperature, no intermediate in the protonation of 8 is
observed. Similar treatment of 14 with 1 equiv of HCl initially
affords the expected mixed dihalide complex Ru(CH-p-C6H4-
Me)(PCy3)2BrCl (17), but this complex rapidly undergoes halide
exchange to give an equilibrium mixture that contains all three
benzylidene complexes 17, Ru(CH-p-C6H4Me)(PCy3)2Br2, and
6 (Scheme 3). Rapid exchange of halide ligands between Ru-
(CHR)(PCy3)2X2 (X ) Cl, I) to yield statistical mixtures of these
complexes with the corresponding mixed dihalide species Ru-
(CHR)(PCy3)2ClI has been noted.31,32 Similarly rapid exchange
of halide ligands in closely related catalysts was the subject of
a recent report.33 However, addition of HCl to 9 does not
(31) Wilhelm, T. E. Ph.D. Thesis, California Institute of Technology,
Pasadena, CA, 1997.
(32) Sanford, M. S. Ph.D. Thesis, California Institute of Technology,
Pasadena, CA, 2001.
(33) Tanaka, K.; Bo¨hm, V. P. W.; Chadwick, D.; Roeper, M.; Braddock,
D. C. Organometallics 2006, 25, 5696.

1916 Organometallics, Vol. 26, No. 8, 2007
Caskey et al.
Figure 4. 50% thermal ellipsoid plot of 26.
Figure 1. 50% thermal ellipsoid plot of 19.
(PCy3)2I2]I (23-I). Addition of PCy3 followed by TlOTf (Tf )
CF3SO2) to a solution of 22 yields soluble [Ru(C-p-C6H4Me)-
(PCy3)2I2]OTf (23-OTf) along with a precipitate of TlI. Com-
pound 23-OTf can also be prepared from 16 in 64% isolated
yield by oxidation with I2 (Scheme 5). Alternatively, reaction
of 22 with PCy3 followed by NaBPh4 in CH2Cl2 affords [Ru-
(C-p-C6H4Me)(PCy3)2I2]BPh4 (23-BPh4) in 83% yield. Except
-
1
for peaks due to BPh4 in the H NMR spectrum of 23-BPh4,
the 1H and 31P NMR spectra of 23-I, 23-OTf, and 23-BPh4 are
identical, which establishes the presence of the discrete [Ru-
(C-p-C6H4Me)(PCy3)2I2]+ unit in all three compounds. Accord-
ingly, the preference for five-coordination in mono- and bis-
tricyclohexylphosphine complexes when the halide ligands are
bromide and iodide appears to be a steric effect. Werner has
reported the formation of similar cationic five-coordinate
carbyne complexes, including structurally characterized 4a via
protonation of vinylidene complexes.11,12 Protonation of
allenylidene complexes similarly affords alkenylcarbyne
complexes.15-19
Figure 2. 50% thermal ellipsoid plot of 22.
When 22 is subjected to excess PPh3 in CH2Cl2, genuine six-
coordinate Ru(C-p-C6H4Me)(PPh3)2I3 is formed. An initial pair
of doublets in the 31P NMR spectrum is observed that is
consistent with a mixed bis-phosphine complex such as Ru(C-
p-C6H4Me)(PCy3)(PPh3)I3 or [Ru(C-p-C6H4Me)(PCy3)(PPh3)-
I2]I, which can then disproportionate into Ru(C-p-C6H4Me)-
(PPh3)2I3 and 23-I (Scheme 6). Compound 23-I is also observed
at short reaction times.
Although pseudo-octahedral 20 was the only Ru-containing
product of oxidation of 8 by C2Cl6, the five-coordinate complex
Ru(C-p-C6H4Me)(PCy3)Cl3 (24) can be isolated in 63% yield
upon treatment of 20 with elemental sulfur, followed by
extraction with toluene to remove the SdPCy3 byproduct.
Unlike 20, 24 is stable for days in CD2Cl2 solution at 28 °C.
Figure 3. 50% thermal ellipsoid plot of the cation in 25.
These oxidation reactions parallel the low-temperature oxida-
tion of Ru(tCPh)(CO)(PPh3)2Cl by I2 to afford six-coordinate
ionic [Ru(tCPh)(CO)(PPh3)2ClI]I, a compound that upon
heating in inert solvent loses CO and forms Ru(tCPh)(PPh3)2-
ClI2.29,34,35
In the case of oxidation of 15 by I2, only 22 is obtained; the
putative six-coordinate bis-phosphine complex Ru(C-p-C6H4-
Me)(PCy3)2I3 is not observed. Nevertheless, addition of 1 equiv
of PCy3 to 22 in CD2Cl2 (in which 22 is quite soluble) gives
rise to a new bis-phosphine complex. However, this complex
is not Ru(C-p-C6H4Me)(PCy3)2I3, even though addition of C6D6
followed by concentration under reduced pressure results in loss
of PCy3 and re-formation of solid 22. Instead, we formulate
this new compound as the ionic species [Ru(C-p-C6H4Me)-
Treatment of 20 with [Ph3C][BF4] in CH2Cl2 at 28 °C results
in the abstraction of one chloride ligand to form a cationic five-
coordinate complex, [Ru(C-p-C6H4Me)(PCy3)2Cl2]BF4 (25). The
1H and 31P NMR chemical shifts are consistent with those of
23-I, 23-OTf, and 23-BPh4, and those reported for [Ru(CCH2-
Ph)(PCy3)2Cl2][B(C6H3(CF3)2-3,5)4] (3a).12 The orange powder
25 can be isolated in 89.4% yield by concentration of the solvent
and washing the remaining residue with pentane and ether.
Attempts to synthesize the five-coordinate complex Ru(C-
p-C6H4Me)(PCy3)F3 through phosphine trapping of 19 with
elemental sulfur, or ligand substitution of 24 or 22 with various
fluoride sources, including AgF, [n-Bu4N]F‚3H2O, TAS-F, and
CsF, have thus far been unsuccessful. This apparent preference
for six-coordination does not hinder intermetal halide exchange
(34) Roper, W. R. J. Organomet. Chem. 1986, 300, 167.
(35) Wright, A. H. Ph.D. Thesis, University of Auckland, Auckland, New
Zealand, 1983.

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1917
Table 2. Selected Bond Lengths and Angles for Benzylidyne Complexes 19, 22, 25, and 26
19
22
25
1.678(3)
26
1.714(3)
Bond Distances (Å)
1.670(5)
Ru-C(1)
1.703(9)
Ru-P(1)
2.4443(14)
2.4444(14)
2.089(4)
F(2): 1.985(4)
F(3): 1.989(4)
2.4142(12)
2.4483(12)
2.4321(12)
2.4600(10)
2.4658(11)
2.0092(19)
Cl(1): 2.4008(10)
Cl(2): 2.3800(10)
Ru-P(2)
Ru-F(1) trans to carbyne
Ru-X cis to carbyne
Ru-X cis to carbyne
Ru-I(3) trans to PCy3
I(1): 2.6905(5)
I(2): 2.6515(6)
2.6992(6)
Cl(1): 2.3527(11)
Cl(2): 2.3359(11)
Bond Angles (deg)
168.8(4)
Ru-C(1)-C(2)
C(1)-Ru-P(1)
C(1)-Ru-P(2)
C(1)-Ru-X cis halide
C(1)-Ru-X cis halide
C(1)-Ru-I(3)
179.9(7)
92.72(4)
92.72(4)
F(2): 94.9(3)
F(3): 98.2(3)
171.4(3)
96.70(11)
95.77(11)
Cl(1): 105.28(11)
Cl(2): 97.80(11)
169.9(3)
93.96(11)
95.20(11)
Cl(1): 89.09(12)
Cl(2): 100.70(11)
97.01(16)
I(1): 93.23(16)
I(2): 102.48(16)
97.95(16)
F(1)-Ru-P(1)
87.27(4)
87.27(4)
85.09(6)
86.07(6)
F(1)-Ru-P(2)
I(3)-Ru-P(1)
164.88(3)
of 19 and 20, which occurs rapidly in dichloromethane.
Attempted comproportionation of 2 equiv of 20 and 1 equiv of
19 led to a complex mixture rapidly at RT, the major product
of which was determined to be the desired compound Ru(C-
p-C6H4Me)(PCy3)2Cl2F (26) by independent synthesis (see
below).
Structures of Oxidized Carbyne Complexes. No five- or
six-coordinate ruthenium-benzylidyne complexes had been
structurally characterized prior to this work, although the
structures of several osmium benzylidyne complexes have been
determined by X-ray diffraction.30,36-40 Accordingly, we ob-
tained the single-crystal X-ray structures of 19, 22, and Ru(C-
p-C6H4Me)(PCy3)2Cl2F (26) for comparison to the few known
ruthenium-carbyne structures. Pale brown 26 was prepared in
74% yield by reaction of 20 with [S(NMe2)3][SiMe3F2] (TAS-
F). Crystallographic data for 19, 22, 25, and 26 are listed in
Table 1. Thermal ellipsoid plots of 19, 22, 25, and 26 are shown
in Figures 1-4.
anate, occupies the position trans to the carbyne ligand.37 In
square-pyramidal 22 and 25, the p-methylbenzylidyne ligand
occupies the apical position (Figures 2, 3). Important bond
lengths and angles for 19, 22, 25, and 26 are listed in Table 2.
The RutC bond length of 1.670(5) Å in 22 is indicative of
a triple bond. This is not significantly smaller than those found
in six-coordinate carbyne complexes such as 19 (1.703(9) Å)
and trans,mer-Ru(tCCHdCMe2)(PPh3)2Cl3 (1.696(6) Å),13 but
is marginally less than that in 26, which exhibits a rather long
RutC bond, 1.714(3) Å in length, comparable to that found in
square-planar 13.24
The slightly greater length of the RutC bond in 22 than that
in the cationic five-coordinate carbyne complex 4a[B(C6H3-
(CF3)2-3,5)4] (1.660(5) Å)11,12 is not statistically significant,
although it is worth noting that the RutC internuclear separation
in cationic 4a is significantly shorter than those of all three six-
coordinate carbyne complexes 19, 26, and Ru(tCCHd
CMe2)(PPh3)2Cl3. However, the RutC bond in cationic 25 is
indistinguishable from those of neutral 19 and 22, and cationic
4a by the 3σ criterion, and is significantly shorter only than
the RutC bond in 26.
The 1H and 31P NMR spectra and solubility properties of 19,
20, and 26 are indicative of six-coordination. As is seen in Figure
1, 19 adopts a pseudo-octahedral geometry in the solid state
such that the two PCy3 ligands are mutually trans, with a
meridional arrangement of the three fluoride ligands. Structurally
characterized complexes of ruthenium with three fluoride ligands
are very rare.41,42 Complex 19 is unique among these in that its
fluoride ligands are all terminal rather than bridging. In general,
fluoride complexes of ruthenium are uncommon but increasingly
well known.43,44 Complex 26 (Figure 4) adopts a similar
geometry in which the unique fluoride ligand is trans to the
carbyne moiety. This geometry parallels that seen in a closely
related complex of osmium, Os(C-p-C6H4NMe2)(PPh3)2Cl2-
(NCS), in which the hardest ligand present, N-bonded thiocy-
Formation of Carbene Complexes from Oxidized Car-
bynes. Addition of Schwartz’s reagent to 20 results in quantita-
45
tive formation of 625 and Cp2ZrCl2 (Scheme 7). At present,
the initial site of hydride attack is unclear, as 6 is the
thermodynamic product. When the reaction is performed in a
NMR spectrometer and monitored at low temperature, no
hydride is observed at any point, but the carbene proton is seen
immediately at -60 °C by 1H NMR spectroscopy. The
thermodynamic preference for the five-coordinate carbene
complex as opposed to the isomeric six-coordinate carbyne-
hydride complex is opposite of that found in related Os
systems.46-48 It is of note that addition of a hydride source to
20 results in formation of a carbene complex, whereas addition
of a fluoride source to 20 results in formation of the carbyne
complex 26, which raises the question of the stability of
R-halocarbene complexes of the type Ru(CXR)L2X2 and may
have implications for metathesis of vinyl halides. We have
recently noted that the new monofluoromethylidene complex
Ru(CHF)(H2IMes)(PCy3)Cl249 forms the corresponding terminal
(36) Clark, G. R.; Marsden, K.; Roper, W. R.; Wright, L. J. J. Am. Chem.
Soc. 1980, 102, 6570.
(37) Clark, G. R.; Edmonds, N. R.; Pauptit, R. A.; Roper, W. R.; Waters,
J. M.; Wright, A. H. J. Organomet. Chem. 1983, 244, C57.
(38) Clark, G. R.; Cochrane, C. M.; Marsden, K.; Roper, W. R.; Wright,
L. J. J. Organomet. Chem. 1986, 315, 211.
(39) Esteruelas, M. A.; Gonza´lez, A. I.; Lo´pez, A. M.; On˜ate, E.
Organometallics 2003, 22, 414.
(40) Hodges, L. M.; Sabat, M.; Harman, W. D. Inorg. Chem. 1993, 32,
371.
(41) Becker, C.; Kieltsch, I.; Broggini, D.; Mezzetti, A. Inorg. Chem.
2003, 42, 8417.
(42) Jasim, N. A.; Perutz, R. N.; Archibald, S. J. J. Chem. Soc., Dalton
Trans. 2003, 2184.
(43) Murphy, E. F.; Murugavel, R.; Roesky, H. W. Chem. ReV. 1997,
97, 3425.
(45) Gell, K. I.; Schwartz, J. J. Am. Chem. Soc. 1981, 103, 2687.
(46) Caulton, K. G. J. Organomet. Chem. 2001, 617, 56.
(47) Spivak, G. J.; Coalter, J. N.; Oliva´n, M.; Eisenstein, O.; Caulton,
K. G. Organometallics 1998, 17, 999.
(48) Espuelas, J.; Esteruelas, M. A.; Lahoz, F. J.; Oro, L. A.; Ruiz, N.
J. Am. Chem. Soc. 1993, 115, 4683.
(44) Doherty, N. M.; Hoffman, N. W. Chem. ReV. 1991, 91, 553.

1918 Organometallics, Vol. 26, No. 8, 2007
Caskey et al.
Scheme 7. Reactivity of 20 with Hydride and Fluoride
Sources
Conclusions
Dehydrochlorination of “first-generation” Grubbs catalysts
can be accomplished in one step by reaction with the bulky
dialkyl germylene Ge(CH[SiMe3]2)2 (10) or in two steps via
reaction with excess phenoxide ion followed by SnCl2. Products
of both processes are diamagnetic square-planar carbyne
complexes of the form Ru(CR)(PCy3)2Cl. The one-step process
works for both R ) alkyl and R ) aryl; in contrast, the two-
step procedure fails at the first step when R ) alkyl. The
benzylidyne complex Ru(C-p-C6H4Me)(PCy3)2Cl (8) is a useful
precursor to the corresponding monohalide and triflate com-
plexes Ru(C-p-C6H4Me)(PCy3)2X (X ) F, Br, I, OTf). These
benzylidyne complexes react rapidly and quantitatively with
ethereal HCl to afford Grubbs catalysts Ru(CH-p-C6H4Me)-
(PCy3)2XCl; when X * Cl, halide exchange occurs rapidly in
solution to generate a mixture of the three possible Grubbs
catalysts Ru(CH-p-C6H4Me)(PCy3)2XCl, Ru(CH-p-C6H4Me)-
(PCy3)2Cl2 (6), and Ru(CH-p-C6H4Me)(PCy3)2X2. The square-
planar complexes undergo ready two-electron oxidation to the
corresponding diamagnetic trihalide benzylidyne complexes,
which are either square-pyramidal Ru(C-p-C6H4Me)(PCy3)X3
(X ) Br, I) or pseudo-octahedral Ru(C-p-C6H4Me)(PCy3)2X3
(X ) F, Cl). Steric effects appear to be responsible for this
dichotomy, as attempts to generate six-coordinate Ru(C-p-C6H4-
Me)(PCy3)2I3 by addition of PCy3 fail, instead affording cationic
[Ru(C-p-C6H4Me)(PCy3)2I2]I. However, six-coordinate Ru(C-
p-C6H4Me)(PPh3)2I3 can be synthesized by addition of excess
PPh3 to Ru(C-p-C6H4Me)(PCy3)I3. One PCy3 ligand can be
removed from Ru(C-p-C6H4Me)(PCy3)2X3 to yield Ru(C-p-
C6H4Me)(PCy3)X3 upon reaction with elemental sulfur only for
X ) Cl. Four structurally characterized complexes, two neutral
six-coordinate bis-phosphine complexes, one neutral five-
coordinate monophosphine complex, and one cationic bis-
phosphine complex, reveal RutC bond lengths in the range
1.67-1.71 Å, consistent with ruthenium-carbon triple bonds.
The five-coordinate complexes are best described as square
pyramidal; the benzylidyne ligand occupies the apical position.
Of the trihalide complexes, only the fluoride-containing com-
plexes Ru(C-p-C6H4Me)(PCy3)2X2F (X ) F, Cl) display
reactivity toward alkynes, catalyzing the formation of conjugated
enynes via dimerization of terminal alkynes. Hydride addition
to Ru(C-p-C6H4Me)(PCy3)2Cl3 re-forms the Grubbs catalyst 6
cleanly.
50-53
carbide complex Ru(C)(H2IMes)(PCy3)Cl2
cleanly and
spontaneously under a number of conditions, thus accounting
for the lack of successful olefin cross-metathesis reactions
involving vinyl fluoride.49 However, the formation of Ru(C)-
(H2IMes)(PCy3)Cl2 upon reaction of 2 with 1,1-disubstituted
vinyl halides is unlikely, as C-C bond cleavage in an
intermediate such as Ru(CXR)L2X2 would be required. Instead,
formation of complexes akin to 20 and 26 is a likely possibility.
We are currently studying reactions of 1 and 2 with appropriately
substituted vinyl halides to address this point.
Alkyne Dimerization. Dimerization of terminal alkynes to
form conjugated enynes54-58 is of interest due to its atom-
economy.59 The enynes so formed are attractive building blocks
in organic syntheses.60 Many systems currently available employ
a metal catalyst and a base to aid in the transformation. Single-
component catalysts are known but are less common.61 Complex
19 was found to effectively catalyze dimerization of terminal
alkynes to give enynes. Catalytic reactions were carried out with
5 mol % 19 in C6D6 in a sealed J. Young NMR tube at 65 °C.
After 28 h, dimerization of phenylacetylene gave at least 96%
conversion to two enyne isomers, Z-1,4-diphenyl-1-buten-3-yne
and 2,4-diphenyl-1-buten-3-yne in a 4:1 ratio, respectively.
Throughout the course of the reaction, 19 showed decomposition
1
by H and 31P NMR but retained some activity at the end of
the reaction. The Z-isomer, the major product here, is the
opposite isomer of that obtained by Ozerov and co-workers in
recent Rh-catalyzed alkyne dimerizations.61 Complex 19 simi-
larly dimerized Me3SiCtCH. While the mechanism of the
transformation mediated by 19 is not known, the fluoride ligand
is essential to activity. This is shown by the fact that only 19
and the monofluoride complex 26 are active, though 26 is less
efficient, under these conditions. The analogous trichloride
complex 20 shows no activity. Metal-vinylidenes are often
implicated in alkyne dimerization and cannot be ruled out at
this point.
Experimental Section
General Procedures. All reactions were carried out using
standard Schlenk techniques under an atmosphere of nitrogen or
in a nitrogen-filled MBraun Labmaster 130 glovebox, unless
otherwise specified. 1H, 13C, 19F, and 31P NMR spectra were
recorded on a Varian Inova 300 MHz or 400 MHz NMR
spectrometer. 1H and 13C spectra were referenced to solvent
signals.62 19F NMR spectra were referenced to external CFCl3 in
CDCl3 (δ ) 0); 31P NMR spectra were referenced to external 85%
H3PO4 (δ ) 0).
Materials. [S(NMe2)3][SiF2Me3] (TAS-F), I2, 1 M and 2 M HCl
in ether, Et3N‚3HF, and py(HF)n were purchased from Aldrich. Br2,
hexachloroethane, NaI, PPh3, LiBr, triethylamine, [n-Bu4N]F‚3H2O,
18-crown-6, trityl tetrafluoroborate, phenylacetylene, and 1,3,5-
trimethoxybenzene were purchased from Acros. Trimethylsily-
lacetylene was purchased from GFS. NaBPh4, TlOTf, XeF2, CsF,
AgF, Cp2ZrHCl (Schwartz’s reagent), and Cp2ZrCl2 were purchased
(49) Macnaughtan, M. L.; Johnson, M. J. A.; Kampf, J. W. Organome-
tallics 2007, 26, 780.
(50) Carlson, R. G.; Gile, M. A.; Heppert, J. A.; Mason, M. H.; Powell,
D. R.; Vander Velde, D.; Vilain, J. M. J. Am. Chem. Soc. 2002, 124, 1580.
(51) Hejl, A.; Trnka, T. M.; Day, M. W.; Grubbs, R. H. Chem. Commun.
2002, 2524.
(52) Romero, P. E.; Piers, W. E.; McDonald, R. Angew. Chem., Int. Ed.
2004, 43, 6161.
(53) Caskey, S. R.; Stewart, M. H.; Kivela, J. E.; Sootsman, J. R.;
Johnson, M. J. A.; Kampf, J. W. J. Am. Chem. Soc. 2005, 127, 16750.
(54) Janiak, C. Coord. Chem. ReV. 2006, 250, 66.
(55) Drozdzak, R.; Allaert, B.; Ledoux, N.; Dragutan, I.; Dragutan, V.;
Verpoort, F. AdV. Synth. Catal. 2005, 347, 1721.
(56) Scha¨fer, M.; Wolf, J.; Werner, H. Dalton Trans. 2005, 1468.
(57) Lee, C. C.; Lin, Y. C.; Liu, Y. H.; Wang, Y. Organometallics 2005,
24, 136.
(58) Katayama, H.; Ozawa, F. Coord. Chem. ReV. 2004, 248, 1703.
(59) Trost, B. M. Science 1991, 254, 1471.
(60) Stang, P. J.; Diederich, F., Modern Acetylene Chemistry; VCH: New
York, 1995; p 506.
(61) Weng, W.; Guo, C. Y.; Celenligil-Cetin, R.; Foxman, B. M.; Ozerov,
O. V. Chem. Commun. 2006, 197.
(62) Gottlieb, H. E.; Kotlyar, V.; Nudelman, A. J. Org. Chem. 1997,
62, 7512.

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1919
from Strem. Elemental sulfur (S8) was purchased from Mallinckrodt.
All bulk solvents were obtained from VWR Scientific and dried
by passage through solvent purification columns according to the
method of Grubbs.63 Deuterated solvents were purchased from CIL
and dried over 4 Å molecular sieves. All liquid reagents were
degassed and then dried over sieves or passed through activated
alumina. Solid reagents were used as received. The starting
compounds [Ru(C-p-C6H4Me)(PCy3)2Cl] (8),24 [Ru(C-p-C6H4Me)-
(PCy3)2Br] (14),24 [Ru(C-p-C6H4Me)(PCy3)2OTf] (16),24 and [Ru-
(CH-p-C6H4Me)(PCy3)2Cl2] (6)25 were synthesized according to
published procedures.
[Ru(C-p-C6H4Me)(PCy3)2F] (9). Syntheses of this compound
were reported previously.24 An improved procedure is as follows.
To a stirred blue-green solution of [Ru(C-p-C6H4Me)(PCy3)2Cl] (8)
(1.001 g, 1.250 mmol) in THF (60 mL) was added [n-Bu4N]F‚
3H2O (0.789 g, 2.50 mmol, 2.00 equiv) as a solid at once. The
solid was washed in with THF (20 mL). The resulting green solution
was stirred for 2.5 h, then concentrated to dryness. The remaining
green solid was slurried in cold acetonitrile (10 mL) for 10 min,
filtered, washed with cold acetonitrile (4 × 5 mL), and dried in
Vacuo for 2 h. Blue-green powder 9 (0.797 g, 1.02 mmol) was
recovered pure in 81.3% yield.
[Ru(C-p-C6H4Me)(PCy3)2I] (15). To a solid mixture of blue-
green [Ru(C-p-C6H4Me)(PCy3)2Cl] (8) (2.029 g, 2.53 mmol) and
excess NaI (3.769 g, 25.1 mmol, 9.92 equiv) was added THF
(240 mL). The heterogeneous mixture was stirred for 1.5 h, over
which time the solution turned brown. The solution was then
concentrated to dryness under vacuum. The brown material was
extracted into toluene (240 mL) and stirred for 1 h. The solution
was filtered through a bed of Celite to remove white sodium salts.
The Celite was washed with toluene (3 × 50 mL) until all color
was removed. The filtrate was concentrated to dryness. The brown
residue was stirred in cold pentane (40 mL) for 1 h and then filtered.
The precipitate was washed with cold pentane (2 × 10 mL) and
dried in Vacuo 4 h. Green-gray powder 15 (1.529 g, 1.71 mmol)
was recovered pure in 67.7% yield. 1H NMR (400 MHz, C6D6): δ
7.83 (d, 3JHH ) 8.2 Hz, 2H C6H4Me), 6.59 (d, 3JHH ) 7.6 Hz, 2H,
C6H4Me), 1.64 (s, 3H, CH3), 2.65, 2.36-2.33, 2.02-1.96, 1.78-
1.76, 1.64-1.62, 1.27-1.17 (all m, 66H, PCy3). 13C{1H} NMR
(100.6 MHz, THF-d8): δ 241.61 (t, JPC ) 17.5 Hz, RutC-Ar),
141.15 and 140.58 (both s, ipso-C and p-C of C6H4Me), 129.99
and 127.82 (both s, C6H4Me), 38.79 (t, JPC ) 9.2 Hz, ipso-C of
P(C6H11)3), 32.06 (br s, m-C of P(C6H11)3), 28.65 (t, JPC ) 5.3 Hz,
o-C of P(C6H11)3), 27.77 (s, p-C of P(C6H11)3), 22.32 (s, CH3). 31P-
{1H} NMR (161.9 MHz, C6D6): δ 40.4 (s). Anal. Calcd for C44H73-
IP2Ru: C, 59.25; H, 8.25. Found: C, 59.06; H, 8.51.
[Ru(CH-p-C6H4Me)(PCy3)2Br2]. To a stirred solution of lithium
bromide (2.070 g, 23.8 mmol, 20.0 equiv) in THF (20 mL) was
added [Ru(CH-p-C6H4Me)(PCy3)2Cl2] (6) (1.000 g, 1.20 mmol) as
a solid. The solid was washed in with CH2Cl2 (40 mL). The solution
was stirred for 3.5 h, then concentrated to dryness. The remaining
purple material was extracted into toluene (40 mL) and stirred for
20 min. The mixture was filtered through a bed of wetted Celite
and the purple color was washed through with toluene (2 × 30
mL). The filtrate was concentrated to dryness. The resulting purple
solid was slurried in cold pentane (20 mL), filtered, washed with
pentane (3 × 5 mL), and dried in Vacuo for 5 h. Purple powder
material (0.945 g) was recovered as ∼86% dibromide product by
1H and 31P NMR; 13% remained incompletely reacted. The purple
powder was resubjected to the reaction conditions three times to
provide the pure purple powder product (0.632 g, 0.682 mmol) in
57.1% yield. 1H NMR (400 MHz, CD2Cl2): δ 19.83 (s, RudCHAr),
8.33 (d, 3JHH ) 6.9 Hz, 2H, C6H4Me), 7.12 (d, 3JHH ) 7.6 Hz, 2H,
C6H4Me), 2.85 (br s, 6H, PCH of PCy3), 2.09 (s, 3H, CH3), 1.80-
1.70, 1.43-1.38, 1.25-1.15 (all m, 60H, PCy3). 13C{1H} NMR
(100.6 MHz, CD2Cl2): δ 295.77 (t, JPC ) 8.8 Hz, RudCHAr),
151.35 (s, p-C of C6H4Me), 140.78 (ipso-C of C6H4Me), 131.71
and 129.61 (both s, C6H4Me), 33.41 (t, JPC ) 9.2 Hz, ipso-C of
P(C6H11)3), 30.42 (br s, m-C of P(C6H11)3), 28.17 (t, JPC ) 5.4 Hz,
o-C of P(C6H11)3), 26.94 (s, p-C of P(C6H11)3), 22.34 (s, CH3). 31P-
{1H} NMR (161.9 MHz, CD2Cl2): δ 36.8 (s). Anal. Calcd for
C44H74Br2P2Ru: C, 57.08; H, 8.06. Found: C, 57.11; H, 8.23.
[Ru(C-p-C6H4Me)(PCy3)2F3] (19). Method A (XeF2). To a
stirred green solution of [Ru(C-p-C6H4Me)(PCy3)2F] (9) (0.199 g,
0.254 mmol) in benzene (25 mL) was added XeF2 (0.058 g, 0.34
mmol, 1.4 equiv) as a white crystalline solid at once. The reaction
mixture was stirred for 45 min, over which time it turned from
green to brown. The mixture was then concentrated to dryness.
The remaining brown residue was slurried in cold hexanes (6 mL)
for 15 min, filtered, and washed with hexanes (3 × 3 mL). The
remaining solid was dried in vacuo 3 h. Pink-gray powder
(0.148 g) was recovered containing a small amount of an unknown
1
purple impurity, which is recognizable in the H NMR spectrum
as two broad peaks centered at δ 12.7 and 11.9 ppm in CD2Cl2.
This impurity also tends to broaden the 19F and 31P NMR shifts of
the product 19, such that the coupling constants cannot be
determined. To remove this impurity, the pink-gray powder was
stirred in CH2Cl2 (10 mL). To the stirred brown solution was added
triethylamine (25.0 µL, 0.180 mmol). The mixture was stirred for
30 min and then concentrated to dryness. The remaining residue
was slurried in cold acetonitrile (6 mL) for 15 min, filtered, washed
with acetonitrile (3 × 3 mL), and dried in Vacuo 2 h. Pale pinkish-
gray powder (0.111 g) was recovered with a minor amount of the
above-mentioned impurity still present. The triethylamine treatment
was repeated once. In this way, gray powder 19 (0.095 g, 0.12
mmol) was recovered in pure form in 45% overall yield. 1H NMR
(400 MHz, CD2Cl2): δ 8.13 (d, 3JHH ) 8.2 Hz, 2H, C6H4Me), 6.70
3
(d, JHH ) 8.0 Hz, 2H, C6H4Me), 2.54 (br s, 6H, PCH of PCy3),
1.67 (s, 3H, CH3), 2.32-2.28, 1.89-1.53, 1.27-1.14 (all m, 60H,
PCy3). 13C{1H} NMR (100.6 MHz, CD2Cl2): δ 147.25 (s, p-C of
C6H4Me), 141.95 (d, JFC ) 11.6 Hz, ipso-C of C6H4Me), 132.34
and 130.27 (both s, C6H4Me), 34.48 (t, JPC ) 9.5 Hz, ipso-C of
P(C6H11)3), 29.03 (br s, m-C of P(C6H11)3), 28.23 (t, JPC ) 5.5 Hz,
o-C of P(C6H11)3), 26.99 (s, p-C of P(C6H11)3), 23.15 (s, CH3). 19F-
2
{1H} NMR (376.29 MHz, CD2Cl2): δ -190.96 (tt, JFF ) 120
2
2
Hz, JPF ) 32 Hz, RuF-trans to carbyne), -419.50 (br d, JFF
)
120 Hz, RuF2-cis to carbyne). 31P{1H} NMR (121.5 MHz, CD2-
Cl2): δ 25.3 (dt, JPF ) 34 Hz, JPF ) 10 Hz). Anal. Calcd for
C44H73F3P2Ru: C, 64.29; H, 8.95. Found: C, 64.34; H, 9.84.
2
2
Method B (AgF). To a stirred green solution of [Ru(C-p-C6H4-
Me)(PCy3)2F] (9) (0.069 g, 0.088 mmol) in THF (7 mL) was added
silver(I) fluoride (0.028 g, 0.22 mmol, 2.5 equiv) as a solid at once.
The reaction vial was wrapped in aluminum foil to protect the
reaction from light. The heterogeneous mixture was stirred for 48
h, over which time the solution turned from green to brown. The
reaction mixture was then filtered through a bed of wetted Celite
and the brown color washed through with THF (2 × 3 mL). The
filtrate was concentrated to dryness. The remaining solid was
slurried in cold acetone (4 mL) for 10 min, filtered, washed with
cold acetone (3 × 2 mL), and dried in Vacuo. Gray powder 19
(0.011 g, 0.014 mmol) was recovered in 16% yield.
[Ru(C-p-C6H4Me)(PCy3)2Cl3] (20). A blue-green solution of
[Ru(C-p-C6H4Me)(PCy3)2Cl] (8) (0.253 g, 0.316 mmol) in toluene
(20 mL) and a solution of hexachloroethane (0.078 g, 0.33 mmol,
1.0 equiv) in toluene (10 mL) were frozen with liquid N2. The
hexachloroethane solution was thawed until it was completely liquid
and added all at once to the ruthenium solution as it just thawed
enough to begin stirring. The reaction mixture was stirred and
allowed to warm to glovebox temperature (30 °C) for 1 h, over
which time the solution turned brown and a precipitate formed.
The reaction mixture was concentrated under vacuum to dryness.
The tan solid was slurried in cold pentane (10 mL) and stirred for
(63) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J. Organometallics 1996, 15, 1518.

1920 Organometallics, Vol. 26, No. 8, 2007
Caskey et al.
10 min. The mixture was filtered. The solid was washed with cold
acetonitrile (3 × 6 mL) and cold pentane (3 × 6 mL) and dried in
Vacuo 6 h. Tan powder 20 (0.145 g, 0.166 mmol) was recovered
PCH of PCy3), 2.48 (s, 3H, CH3), 1.89-1.75, 1.47-1.17 (all m,
60H, PCy3). 31P{1H} NMR (161.9 MHz, CD2Cl2): δ 51.1 (s). NMR
spectra for the mixture of 23-I are reproduced in the Supporting
Information.
1
pure in 52.5% yield. H NMR (400 MHz, CD2Cl2): δ 8.16 (d,
3
3JHH ) 8.5 Hz, 2H, C6H4Me), 7.29 (d, JHH ) 8.5 Hz, 2H, C6H4-
[Ru(C-p-C6H4Me)(PCy3)2I2]OTf (23-OTf). Method A. To a
stirred green-blue solution of [Ru(C-p-C6H4Me)(PCy3)2OTf] (16)
(0.063 g, 0.069 mmol) in 10 mL of THF was added rapidly a
solution of iodine (0.018 g, 0.071 mmol, 1.0 equiv) in 2 mL of
THF. The solution was stirred for 1 h, over which time the solution
turned brown and a green precipitate formed. The reaction mixture
was concentrated to dryness under vacuum. The remaining solid
was slurried in pentane (8 mL) and stirred for 10 min. The mixture
was filtered, washed with benzene (3 × 3 mL) and pentane (3 ×
3 mL), and dried in Vacuo 3 h. Bright green powder 23-OTf
(0.052 g, 0.044 mmol) was recovered in 64.2% yield.
Me), 2.68 (m, 6H, PCH of PCy3), 2.42 (s, 3H, CH3), 2.14-2.11,
1.87-1.62, 1.30-1.11 (all m, 60H, PCy3). 31P{1H} NMR (121.5
MHz, CD2Cl2): δ 18.2 (s). Anal. Calcd for C44H73Cl3P2Ru: C,
60.64; H, 8.44. Found: C, 60.72; H, 8.31. Attempts to obtain a
13C{1H} NMR spectrum of this compound have failed due to low
solubility and decomposition at elevated concentration.
[Ru(C-p-C6H4Me)(PCy3)Br3] (21). To a 20 mL scintillation vial
was added a blue-green solution of [Ru(C-p-C6H4Me)(PCy3)2Br]
(14) (0.102 g, 0.121 mmol) in dry benzene (10 mL) and a stirbar.
The vial was sealed with a septum and secured with copper wire.
The sealed solution was removed from the glovebox. To the stirred
solution was added by syringe bromine (0.306 mL, 0.119 mmol,
0.986 equiv) in the form of a freshly prepared stock solution (0.389
M) in dry benzene. The reaction mixture was stirred for 1 h, over
which time the solution turned brown and an orange-brown
precipitate formed. The vial was returned to the glovebox. The
reaction mixture was concentrated to ∼2 mL of solution and filtered.
The remaining solid was dried in Vacuo 4 h. The tan powder
(0.095 g) was recovered. Integration of the 31P NMR signals
indicates 63% 21 and 37% [BrPCy3]Br and, therefore, an 80% yield
of 21. [BrPCy3]Br and 21 could not be separated due to similar
solubilities. Note: By reaction with Br2, trace water or use of
toluene as solvent can each generate HBr in solution, which reacts
rapidly with Ru(C-p-C6H4Me)(PCy3)2Br (14) to form Ru(CH-p-
C6H4Me)(PCy3)2Br2. 1H NMR (400 MHz, CD2Cl2): δ 8.03 (d, 3JHH
Method B. To a stirred red-brown solution of [Ru(C-p-C6H4-
Me)(PCy3)I3] (22) (0.152 g, 0.176 mmol) in 10 mL of CH2Cl2 was
added a solution of PCy3 (0.054 g, 0.19 mmol, 1.1 equiv) in 5 mL
of CH2Cl2. The solution was stirred for 5 min, over which time the
red-brown solution darkened slightly. Solid thallium(I) triflate
(0.067 g, 0.19 mmol, 1.1 equiv) was added and washed in with
CH2Cl2 (2 mL). A yellow precipitate formed immediately and the
solution turned green-brown. The heterogeneous mixture was stirred
for 1 h, filtered through a bed of wetted Celite, and washed through
with CH2Cl2 (3 × 5 mL). The filtrate was concentrated to dryness
under vacuum. The remaining solid was slurried in pentane (8 mL)
and stirred for 10 min. The mixture was filtered, washed in with
benzene (3 × 5 mL) and pentane (3 × 5 mL), and dried in Vacuo
4 h. Bright green powder 23-OTf (0.186 g, 0.159 mmol) was
1
recovered pure in 90.4% yield. H NMR (400 MHz, CD2Cl2): δ
7.88 (d, 3JHH ) 8.4 Hz, 2H, C6H4Me), 7.25 (d, 3JHH ) 8.0 Hz, 2H,
C6H4Me), 3.45 (br s, 6H, PCH of PCy3), 2.46 (s, 3H, CH3), 1.92-
1.75, 1.49-1.19 (all m, 60H, PCy3). 13C{1H} NMR (100.6 MHz,
CD2Cl2, -20 °C): δ 293.24 (br s, RutC-Ar), 152.07 (s, p-C of
C6H4Me), 131.94 (ipso-C of C6H4Me), 130.94 and 130.76 (both s,
C6H4Me), 38.02 (br s, ipso-C of P(C6H11)3), 31.57 (br s, m-C of
P(C6H11)3), 27.62 (t, JPC ) 5.0 Hz, o-C of P(C6H11)3), 26.16 (s,
p-C of P(C6H11)3), 23.32 (s, CH3). 19F{1H} NMR (376.3 MHz, CD2-
Cl2): δ -79.36 (s, OTf). 31P{1H} NMR (161.9 MHz, CD2Cl2): δ
51.1 (s). Anal. Calcd for C45H73F3I2O3P2RuS: C, 46.28; H, 6.30.
Found: C, 46.31; H, 6.50.
3
) 8.2 Hz, 2H, C6H4Me), 7.30 (d, JHH ) 7.9 Hz, 2H, C6H4Me),
3.07-2.98 (m resembles q, 3H, PCH of PCy3), 2.41 (s, 3H, CH3),
2.14-1.96, 1.84-1.48, 1.39-1.22 (all m, [BrPCy3]Br and 21-PCy3).
31P{1H} NMR (161.9 MHz, CD2Cl2): δ 101.69 (s, [BrPCy3]Br),
69.57 (s, 21). NMR spectra for the mixture of 21 and [BrPCy3]Br
are reproduced in the Supporting Information.
[Ru(C-p-C6H4Me)(PCy3)I3] (22). To a stirred gray solution of
[Ru(C-p-C6H4Me)(PCy3)2I] (15) (0.200 g, 0.224 mmol) in 25 mL
of benzene was added dropwise a solution of iodine (0.059 g, 0.23
mmol, 1.0 equiv) in 8 mL of benzene. The solution was stirred for
1 h, over which time the solution turned brown and a precipitate
formed. The reaction mixture was concentrated under vacuum to
one-quarter of the initial volume. The precipitate was filtered from
the solution, washed with benzene (3 × 2 mL), and dried in Vacuo
3 h. Brown powder 22 (0.152 g, 0.175 mmol) was recovered purely
[Ru(C-p-C6H4Me)I2(PCy3)2]BPh4 (23-BPh4). To a stirred red-
brown solution of [Ru(C-p-C6H4Me)(PCy3)I3] (22) (0.142 g, 0.165
mmol) in 6 mL of CH2Cl2 was added a solution of PCy3 (0.046 g,
0.16 mmol, 1.0 equiv) in 2 mL of CH2Cl2. The solution was stirred
for 5 min, over which time the red-brown solution darkened slightly.
Solid NaBPh4 (0.084 g, 0.25 mmol, 1.5 equiv) was added and
washed in with CH2Cl2 (2 mL). A white precipitate formed and
the solution turned green-brown. The heterogeneous mixture was
stirred for 1 h, filtered through a bed of CH2Cl2-wetted Celite, and
washed through with CH2Cl2 (3 × 15 mL). The filtrate was
concentrated to dryness under vacuum. The remaining solid was
slurried in pentane (8 mL) and stirred for 30 min. The mixture
was filtered, washed with pentane (3 × 5 mL), and dried in Vacuo
6 h. Bright green powder 23-BPh4 (0.183 g, 0.137 mmol) was
1
3
in 78.2% yield. H NMR (400 MHz, CD2Cl2): δ 8.06 (d, JHH
)
8.2 Hz, 2H, C6H4Me), 7.22 (d, 3JHH ) 8.2 Hz, 2H, C6H4Me), 3.30
(m resembles q, 3H, PCH of PCy3), 2.38 (s, 3H, CH3), 2.04-1.92,
1.84-1.72, 1.61-1.52, 1.38-1.19 (all m, 30H, PCy3). 13C{1H}
NMR (100.6 MHz, CD2Cl2): δ 287.24 (d, JPC ) 10.7 Hz, Rut
C-Ar), 149.80 (s, ipso-C of C6H4Me), 134.46 (s, p-C of C6H4-
Me), 131.86 and 131.07 (both s, C6H4Me), 37.82 (d, JPC ) 21.9
Hz, ipso-C of P(C6H11)3), 31.47 (d, JPC ) 2.1 Hz, m-C of P(C6H11)3),
28.14 (d, JPC ) 11.2 Hz, o-C of P(C6H11)3), 26.58 (s, p-C of
P(C6H11)3), 23.27 (s, CH3). 31P{1H} NMR (161.9 MHz, CD2Cl2):
δ 66.5 (s). Anal. Calcd for C26H40I3PRu: C, 36.09; H, 4.66.
Found: C, 36.10; H, 4.42.
1
recovered pure in 83.0% yield. H NMR (400 MHz, CD2Cl2): δ
7.89 (d, 3JHH ) 8.2 Hz, 2H, C6H4Me), 7.32 (br s, 8H, o-H of BPh4),
3
7.22 (d, JHH ) 8.2 Hz, 2H, C6H4Me), 7.03 (apparent t, 8H, m-H
of BPh4), 6.88 (t, 3JHH ) 7.3 Hz, 4H, p-H of BPh4) 3.47 (br s, 6H,
PCH of PCy3), 2.43 (s, 3H, CH3), 1.93-1.75, 1.51-1.16 (all m,
60H, PCy3). 31P{1H} NMR (161.9 MHz, CD2Cl2): δ 51.1 (s). Anal.
Calcd for C68H93BI2P2Ru: C, 61.04; H, 7.01. Found: C, 61.50; H,
7.57.
Formation of [Ru(C-p-C6H4Me)(PCy3)2I2]I (23-I). To a solid
sample of PCy3 (0.004 g, 0.01 mmol, 1 equiv) was added a red-
brown solution of [Ru(C-p-C6H4Me)(PCy3)I3] (22) (0.012 g, 0.013
mmol) in CD2Cl2 (ca. 0.75 mL). The solution was mixed well by
pipet, and the solution darkened slightly. After 20 min the 1H and
31P NMR spectra were obtained, and the only observable species
was identified as [Ru(C-p-C6H4Me)(PCy3)2I2]I (23-I). Note: At-
tempts at isolation of 23-I generally led to mixtures of 22 and 23-
[Ru(C-p-C6H4Me)(PPh3)2I3]. To a solid mixture of brown [Ru-
(C-p-C6H4Me)(PCy3)I3] (22) (0.152 g, 0.176 mmol) and triph-
enylphosphine (0.235 g, 0.896 mmol, 5.10 equiv) was added CH2Cl2
(15 mL). The reaction mixture was stirred for 1 h. The solution
was concentrated to dryness. The remaining brown residue was
1
3
I. H NMR (400 MHz, CD2Cl2): δ 7.88 (d, JHH ) 8.4 Hz, 2H,
3
C6H4Me), 7.27 (d, JHH ) 8.0 Hz, 2H, C6H4Me), 3.46 (br s, 6H,

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1921
slurried in cold pentane (8 mL) for 10 min, filtered, and washed
with acetonitrile (3 × 5 mL) and pentane (3 × 3 mL). The
remaining solid was dried in Vacuo overnight. The impure orange
powder (0.141 g) thus recovered was resubjected to the reaction
conditions to eliminate some PCy3-containing products. Orange
powder product (0.071 g, 0.064 mmol) was then recovered pure in
slurried in cold pentane (8 mL) for 20 min, filtered, and washed
with pentane (3 × 3 mL). The remaining solid was dried in Vacuo
3 h. Tan powder 26 (0.055 g, 0.64 mmol) was recovered pure in
1
3
74% yield. H NMR (400 MHz, CD2Cl2): δ 7.96 (d, JHH ) 8.4
Hz, 2H, C6H4Me), 7.19 (d, 3JHH ) 8.0 Hz, 2H, C6H4Me), 2.67 (br
s, 6H, PCH of PCy3), 2.35 (s, 3H, CH3), 2.08-2.02, 1.72-1.61,
1.40-1.07 (all m, 60H, PCy3). 13C{1H} NMR (100.6 MHz, CD2-
Cl2): δ 293.93 (d, JFC ) 150.7 Hz, RutC-Ar), 146.23 (s, p-C of
C6H4Me), 143.85 (d, JFC ) 11.4 Hz, ipso-C of C6H4Me), 131.36
and 129.38 (both s, C6H4Me), 34.38 (t, JPC ) 8.9 Hz, ipso-C of
P(C6H11)3), 29.25 (br s, m-C of P(C6H11)3), 28.17 (t, JPC ) 5.0 Hz,
o-C of P(C6H11)3), 26.80 (s, p-C of P(C6H11)3), 22.77 (s, CH3). 19F-
1
36% yield. H NMR (400 MHz, CD2Cl2): δ 8.09-8.02 (m, 12H,
PPh3), 7.44 (d, 3JHH ) 8.4 Hz, 2H, C6H4Me), 7.49-7.35 (m, 18H,
3
PPh3), 6.58 (d, JHH ) 8.0 Hz, 2H, C6H4Me), 2.25 (s, 3H, CH3).
31P{1H} NMR (161.9 MHz, CD2Cl2): δ -1.4 (s). Anal. Calcd for
C44H37I3P2Ru: C, 47.63; H, 3.36. Found: C, 47.67; H, 3.52.
Attempts to obtain a 13C{1H} NMR spectrum of this compound
have failed due to low solubility and decomposition at elevated
concentration.
2
{1H} NMR (376.3 MHz, CD2Cl2): δ -219.4 (t, JPF ) 41 Hz).
2
31P{1H} NMR (161.9 MHz, CD2Cl2): δ 28.5 (d, JPF ) 41 Hz).
Anal. Calcd for C44H73FCl2P2Ru: C, 61.81; H, 8.61. Found: C,
62.11; H, 8.50.
[Ru(C-p-C6H4Me)(PCy3)Cl3] (24). To a stirred tan solution of
[Ru(C-p-C6H4Me)(PCy3)2Cl3] (20) (0.157 g, 0.180 mmol) in 10 mL
of CH2Cl2 was added solid yellow S8 (0.007 g, 0.03 mmol, 0.2
equiv). The sulfur was washed in with CH2Cl2 (2 mL). The solution
was stirred for 30 min, over which time the solution turned red-
brown. The reaction mixture was filtered and the filtrate concen-
trated to dryness under vacuum. The remaining residue was slurried
in cold toluene (2 mL) and stirred for 10 min. The mixture was
filtered, washed with cold toluene (2 × 2 mL) and cold pentane
(3 × 3 mL), and dried in Vacuo 6 h. Orange-brown powder 24
(0.067 g, 0.11 mmol) was recovered purely in 63% yield. 1H NMR
(400 MHz, CD2Cl2): δ 7.98 (d, 3JHH ) 8.2 Hz, 2H, C6H4Me), 7.35
Attempts to Synthesize [Ru(CH-p-C6H4Me)(PCy3)2F2] (7) by
Ligand Substitution. Method A. A purple solution of [Ru(CH-
p-C6H4Me)(PCy3)2Cl2] (6) (0.010 g, 0.012 mmol) and 18-crown-6
(0.005 g, 0.02 mmol, 1 equiv) in THF (ca. 0.5 mL) was added to
white powder CsF (0.033 g, 0.22 mmol, 18 equiv). The heteroge-
neous mixture was transferred to an NMR tube by pipet and washed
in with DME (ca. 0.5 mL). The reaction was monitored by 19F and
31P NMR spectroscopy. After 4 h, the 31P NMR spectrum showed
the following. 31P{1H} NMR (161.9 MHz, THF-DME): δ 36.6
(6, 83.3%) and 11.0 (free PCy3, 16.7%). After 22 h, the solution
was green-brown and the 31P NMR spectrum showed the following.
3
(d, JHH ) 8.2 Hz, 2H, C6H4Me), 2.85 (m resembles q, 3H, PCH
2
31P{1H} NMR (161.9 MHz, THF-DME): δ 47.1 (d, JFP ) 36
of PCy3), 2.43 (s, 3H, CH3), 2.00-1.57, 1.36-1.15 (all m, 30H,
PCy3). 13C{1H} NMR (100.6 MHz, CD2Cl2): δ 302.47 (d, JPC
)
Hz, 9, 25.4%), 42.6 (8, 3.5%), 36.6 (6, 30.3%), and 11.0 (40.8%).
After 48 h, the 31P NMR spectrum showed the following. 31P{1H}
13.8 Hz, RutC-Ar), 150.32 (s, ipso-C of C6H4Me), 140.25 (s,
p-C of C6H4Me), 131.56 and 130.94 (both s, C6H4Me), 34.98 (d,
JPC ) 23.0 Hz, ipso-C of P(C6H11)3), 30.64 (d, JPC ) 1.5 Hz, m-C
of P(C6H11)3), 28.02 (d, JPC ) 11.5 Hz, o-C of P(C6H11)3), 26.42
(s, p-C of P(C6H11)3), 23.34 (s, CH3). 31P{1H} NMR (161.9 MHz,
CD2Cl2): δ 72.2 (s). Anal. Calcd for C26H40Cl3PRu: C, 52.84; H,
6.82. Found: C, 53.13; H, 7.11.
2
NMR (161.9 MHz, THF-DME): δ 47.1 (d, JFP ) 36 Hz, 9,
30.1%), 42.6 (8, 3.8%), 36.6 (6, 7.1%), and 11.0 (59.0%). The 19
NMR was consistent with the formation of 9.
F
Method B. A purple solution of [Ru(CH-p-C6H4Me)(PCy3)2Cl2]
(6) (0.010 g, 0.012 mmol) in C6D6 (ca. 0.75 mL) was added to
white crystalline [n-Bu4N]F‚3H2O (0.009 g, 0.03 mmol, 2.5 equiv).
The sample was mixed well and transferred to an NMR tube by
pipet. The solution turned brown rapidly. The reaction progress
[Ru(C-p-C6H4Me)(PCy3)2Cl2]BF4 (25). To a stirred golden
solution of [Ru(C-p-C6H4Me)(PCy3)2Cl3] (20) (0.101 g, 0.116
mmol) in CH2Cl2 (8 mL) was added a bright yellow solution of
trityl tetrafluoroborate (0.040 g, 0.12 mmol, 1.1 equiv) in CH2Cl2
(4 mL). The trityl solution was washed in with CH2Cl2 (2 mL).
The reaction mixture turned orange rapidly. The solution was stirred
for 1.5 h, then concentrated to dryness under vacuum. The
remaining solid was slurried in pentane (5 mL) and stirred for 10
min. The mixture was filtered, washed with pentane (3 × 3 mL)
and ether (3 × 3 mL), and dried in Vacuo 5 h. Orange powder 25
(0.096 g, 0.10 mmol) was recovered purely in 89% yield. 1H NMR
(400 MHz, CD2Cl2): δ 7.78 (d, 3JHH ) 8.2 Hz, 2H, C6H4Me), 7.37
1
was monitored by H, 19F, and 31P NMR spectroscopies. After 25
min, the 31P NMR spectrum showed the following. 31P{1H} NMR
(121.5 MHz, C6D6): δ 36.4 (6, (SM), 45.5%) and 10.5 (free PCy3,
54.5%). After 24 h, the 31P NMR spectrum showed the following.
31P{1H} NMR (161.9 MHz, C6D6): δ 55.8 (10.4%), 54.5 (6.6%),
50.6 (10.4%), 36.4 (6, (SM), 34.4%), and 10.5 (free PCy3, 59.0%).
Similar results were obtained when the reaction was repeated with
THF as the solvent.
Reaction of 14 with HCl in Ether. To a blue NMR solution of
[Ru(C-p-C6H4Me)(PCy3)2Br] (14) (0.009 g, 0.01 mmol) in C6D6
(ca. 0.75 mL) was added 2 M HCl in ether (5.1 µL, 0.010 mmol,
1.0 equiv). The NMR tube was then rapidly sealed and inverted
three times to mix. Upon mixing, the solution immediately turned
3
(d, JHH ) 8.0 Hz, 2H, C6H4Me), 2.89 (br s, 6H, PCH of PCy3),
2.47 (s, 3H, CH3), 1.93-1.73, 1.52-1.15 (all m, 60H, PCy3). 13C-
{1H} NMR (100.6 MHz, CD2Cl2): δ 299.69 (br s, RutC-Ar),
152.70 (s, p-C of C6H4Me), 137.50 (ipso-C of C6H4Me), 131.89
and 131.34 (both s, C6H4Me), 34.98 (t, JPC ) 9.6 Hz, ipso-C of
P(C6H11)3), 30.64 (br s, m-C of P(C6H11)3), 27.98 (t, JPC ) 5.6 Hz,
o-C of P(C6H11)3), 26.50 (s, p-C of P(C6H11)3), 23.56 (s, CH3). 19F-
{1H} NMR (376.3 MHz, CD2Cl2): δ -153.31 (s, BF4). 31P{1H}
NMR (161.9 MHz, CD2Cl2): δ 49.9 (s). Anal. Calcd for C44H73-
BCl2F4P2Ru: C, 57.27; H, 7.97. Found: C, 57.26; H, 8.16.
1
red-purple. The reaction progress was monitored by H and 31P
NMR spectroscopy. After 15 min, the 31P NMR spectrum showed
the following. 31P{1H} NMR (161.9 MHz, C6D6): δ 37.1 ([Ru-
(CH-p-C6H4Me)(PCy3)2Br2], 21.1%), 36.8 ([Ru(CH-p-C6H4Me)-
(PCy3)2BrCl] (17), 55.1%), and 36.4 ([Ru(CH-p-C6H4Me)(PCy3)2-
1
Cl2] (6), 23.7%). The H NMR spectrum showed three carbene
peaks consistent with this mixture, two of which are associated
with [Ru(CH-p-C6H4Me)(PCy3)2Br2] and 6, and the third attributed
to [Ru(CH-p-C6H4Me)(PCy3)2BrCl] (17). 1H NMR (400 MHz,
C6D6): δ 20.50 (s). The reaction mixture remained unchanged
overnight.
[Ru(C-p-C6H4Me)(PCy3)2Cl2F] (26). To a solid mixture of tan
[Ru(C-p-C6H4Me)(PCy3)2Cl3] (20) (0.075 g, 0.086 mmol) and tris-
(dimethylamino)sulfonium difluorotrimethylsilicate (TAS-F)
(0.026 g, 0.094 mmol, 1.1 equiv) was added CH2Cl2 (10 mL). The
reaction mixture was stirred for 3 h, over which time it turned from
tan to purple to brown. The solution was concentrated to dryness.
The remaining brown residue was extracted into toluene (8 mL),
filtered, and washed with toluene (3 × 3 mL). The filtrate was
evaporated to dryness in Vacuo. The remaining brown residue was
Reaction of 9 with HCl in Ether. To a green NMR solution of
[Ru(C-p-C6H4Me)(PCy3)2F] (9) (0.001 g, 0.01 mmol) in C6D6 (ca.
0.75 mL) was added 1 M HCl in ether (12.2 µL, 0.0122 mmol,
1.00 equiv). The NMR tube was then rapidly sealed and inverted
three times to mix. The solution turned brown slowly. The reaction

1922 Organometallics, Vol. 26, No. 8, 2007
Caskey et al.
progress was monitored by 1H and 31P NMR spectroscopies. After
30 min, the 31P NMR spectrum showed the following. 31P{1H}
NMR (161.9 MHz, C6D6): δ 46.2 (br s, 9, (SM), 23.4%) and 44.6
(br d, J ) 26.9 Hz, 3.3%), and 36.4 ([Ru(CH-p-C6H4Me)(PCy3)2-
Cl2] (6), 73.3%). After 16 h, the 31P NMR spectrum showed the
following. 31P{1H} NMR (161.9 MHz, C6D6): δ 46.2 (br s, 9 (SM),
20.5%), 36.4 ([Ru(CH-p-C6H4Me)(PCy3)2Cl2] (6), 72.8%), and 10.5
(free PCy3, 6.7%). The 1H NMR spectrum showed only one carbene
peak associated with [Ru(CH-p-C6H4Me)(PCy3)2Cl2] (6).
N2. A clear solution of Cp2ZrHCl (0.004 g, 0.01 mmol, 1 equiv) in
CD2Cl2 (ca. 0.5 mL) was added on top of the frozen Ru sample.
The Zr solution was frozen with liquid N2. The tube was sealed,
and the overlying atmosphere was evacuated. The NMR probe was
cooled to -60 °C. The NMR sample was allowed to thaw slightly
outside the NMR to ensure the tube would not explode in the NMR
probe. The tube was then inserted into the NMR probe and allowed
to equilibrate for 3 min, and the reaction progress was monitored
by 1H NMR spectroscopy. The characteristic carbene peak of [Ru-
(CH-p-C6H4Me)(PCy3)2Cl2] (6) was observed immediately. No
Reaction of 9 with Et3N‚3HF. To a green NMR solution of
[Ru(C-p-C6H4Me)(PCy3)2F] (9) (0.009 g, 0.01 mmol) in C6D6 (ca.
0.75 mL) was added Et3N‚3HF (2.0 µL, 0.012 mmol, 1.0 equiv).
The NMR tube was then rapidly sealed and inverted three times to
mix. The solution color remained unchanged. The reaction progress
1
other carbene peaks or hydrides were ever observed by H NMR
spectroscopy.
Catalytic Alkyne Dimerization Reactions. To a 0.015 mM
C6D6 solution of brown [Ru(C-p-C6H4Me)(PCy3)2F3] (19) in a J.
Young NMR tube was added a terminal alkyne (20 equiv) and an
internal standard, 1,3,5-trimethoxybenzene (1 equiv). The tube was
sealed and the solution frozen with liquid N2. The overlying
atmosphere was evacuated. The tube was heated in an oil bath at
65 °C. The reaction progress was monitored by NMR spectroscopy.
1
was monitored by H and 31P NMR spectroscopies. After 20 min,
the 31P NMR spectrum showed the following. 31P{1H} NMR (161.9
MHz, C6D6): δ 46.2 (br s, 9, (SM), 76.9%) and 44.6 (br d, J )
26.9 Hz, 23.1%). After 16 h, the 31P NMR spectrum showed the
following. 31P{1H} NMR (161.9 MHz, C6D6): δ 46.0 (br s, 9 (SM))
and minor 10.3 (free PCy3). No carbene peaks were ever visible in
Dimerization of Phenylacetylene. After 28 h, integration of the
1H NMR spectrum showed, relative to the internal standard, at least
96% conversion to two enyne isomers, (Z)-1,4-diphenyl-1-buten-
3-yne and 2,4-diphenyl-1-buten-3-yne in a 4:1 ratio, respectively.
1
the H NMR.
Reaction of 22 with PCy3 and Reprecipitation with Benzene.
To a solid sample of PCy3 (0.004 g, 0.01 mmol, 1 equiv) was added
a red-brown solution of [Ru(C-p-C6H4Me)(PCy3)I3] (22) (0.010 g,
0.012 mmol) in CD2Cl2 (ca. 0.75 mL). The solution was mixed
well by pipet and the solution darkened slightly. After 20 min the
1H and 31P NMR spectra were obtained. The 31P NMR spectrum
indicated the presence of only [Ru(C-p-C6H4Me)(PCy3)2I2]I (23-I)
(31P{1H} NMR (161.9 MHz, CD2Cl2): δ 51.1 (s)). The sample
was transferred to a small vial, and C6D6 (ca. 0.75 mL) was added.
The sample was concentrated slowly under vacuum to remove
approximately half the volume. A precipitate formed. The hetero-
geneous sample was transferred to an NMR tube. The 31P NMR
spectrum indicated the presence of only broadened PCy3 (31P{1H}
NMR (161.9 MHz, CD2Cl2): δ 11.5 (br s)). The sample was filtered
through a pipet filter and washed with minimal C6D6. The brown
solid precipitate was dissolved in CD2Cl2 (ca. 0.75 mL). The 31P
NMR spectrum indicated the presence of only 22 (31P{1H} NMR
(161.9 MHz, CD2Cl2): δ 66.2 (br s)).
Dimerization of Trimethylsilylacetylene. After 28 h, integration
of the 1H NMR spectrum showed, relative to the internal standard,
64.0% conversion to two enyne isomers, (Z)-1,4-bis(trimethylsilyl)-
1-buten-3-yne and 2,4-bis(trimethylsilyl)-1-buten-3-yne in a 2:1
ratio, respectively.
Crystal Structure Determinations. Complex 19. Gray plates
of 19 were grown by vapor diffusion of pentane into a dichlo-
romethane solution at -35 °C. A crystal of dimensions 0.10 ×
0.06 × 0.06 mm was mounted on a standard Bruker SMART 1K
CCD-based X-ray diffractometer equipped with a LT-2 low-
temperature device and normal focus Mo-target X-ray tube (λ )
0.71073 A) operated at 2000 W power (50 kV, 40 mA). The X-ray
intensities were measured at 123(2) K; the detector was placed at
a distance 4.969 cm from the crystal. A total of 2480 frames were
collected with a scan width of 0.5° in ω and φ with an exposure
time of 60 s/frame. The integration of the data yielded a total of
28 679 reflections to a maximum 2θ value of 45.28° of which 3141
were independent and 2171 were greater than 2σ(I). The final cell
constants were based on the xyz centroids of 3923 reflections above
10σ(I). Analysis of the data showed negligible decay during data
collection; the data were processed with SADABS and corrected
for absorption. The structure was solved and refined with the Bruker
SHELXTL (version 6.12) software package, using the space group
P2(1)/m with Z ) 2 for the formula C44H72P2F3Ru‚(CH2Cl2). All
non-hydrogen atoms were refined anisotropically with the hydrogen
atoms placed in idealized positions. The complex lies on a
crystallographic mirror plane. Full matrix least-squares refinement
based on F2 converged at R1 ) 0.0530 and wR2 ) 0.0969 [based
on I > 2σ(I)], R1 ) 0.0953 and wR2 ) 0.1109 for all data.
Additional details are presented in the Supporting Information.
Halide Exchange between 19 and 20. To a tan solution of [Ru-
(C-p-C6H4Me)(PCy3)2Cl3] (20) (0.011 g, 0.013 mmol) in CD2Cl2
(ca. 0.5 mL) was added a gray-brown solution of [Ru(C-p-C6H4-
Me)(PCy3)2F3] (19) (0.006 g, 0.007 mmol, 0.5 equiv) in CD2Cl2
(ca. 0.5 mL). The resulting orange-red solution was mixed well
and transferred to an NMR tube by pipet. The reaction progress
1
was monitored by H, 19F, and 31P NMR spectroscopies. After 20
min, the 31P NMR spectrum showed the following. 31P{1H} NMR
(161.9 MHz, CD2Cl2): δ 50.0 (s, 6.6%), 36.3 (s, 6, 8.6%), 28.5 (d,
J ) 41 Hz, 26, 41.7%), 24.6 (s, 26.5%), and 18.2 (s, 20, 16.6%).
After 16 h, the 31P NMR spectrum was essentially unchanged.
Reaction of 20 with Schwartz’s Reagent (Cp2ZrHCl). To a
solid sample of Schwartz’s reagent, Cp2ZrHCl (0.003 g, 0.01 mmol,
1 equiv), was added a tan solution of [Ru(C-p-C6H4Me)(PCy3)2-
Cl3] (20) (0.009 g, 0.01 mmol) in CD2Cl2 (ca. 0.75 mL). The
solution was mixed well by pipet and turned from tan to red rapidly.
After 20 min the 1H and 31P NMR spectra were obtained. Integration
of the 31P NMR spectrum indicated [Ru(CH-p-C6H4Me)(PCy3)2-
Complex 22. Brown needles of 22 were grown from a dichlo-
romethane-d2 solution at -35 °C. A crystal of dimensions 0.50 ×
0.33 × 0.33 mm was cut from a larger crystal and mounted on a
standard Bruker SMART 1K CCD-based X-ray diffractometer
equipped with a LT-2 low-temperature device and normal focus
Mo-target X-ray tube (λ ) 0.71073 A) operated at 2000 W power
(50 kV, 40 mA). The X-ray intensities were measured at 123(2)
K; the detector was placed at a distance 4.980 cm from the crystal.
A total of 3692 frames were collected with a scan width of 0.2° in
ω and φ with an exposure time of 15 s/frame. The integration of
the data yielded a total of 64 836 reflections to a maximum 2θ
value of 56.58° of which 7155 were independent and 6344 were
greater than 2σ(I). The final cell constants (Table 1) were based
on the xyz centroids of 8129 reflections above 10σ(I). Analysis of
1
Cl2] (6) (91%) and minor free PCy3 (9%). H NMR spectroscopy
indicated the presence of [Ru(CH-p-C6H4Me)(PCy3)2Cl2] (6) and
1
Cp2ZrCl2 as the only Zr compound. The H and 31P NMR spectra
were compared to literature values and independently synthesized
samples ([Ru(CH-p-C6H4Me)(PCy3)2Cl2], (6))25 or commercial
compounds (PCy3 and Cp2ZrCl2).
Reaction of 20 with Schwartz’s Reagent (Cp2ZrHCl) at Low
Temperature. To a J. Young NMR tube was added a golden
solution of [Ru(C-p-C6H4Me)(PCy3)2Cl3] (20) (0.010 g, 0.012
mmol) in CD2Cl2 (ca. 0.50 mL). The solution was frozen with liquid

Four-, FiVe-, and Six-Coordinate Ru Carbyne Complexes
Organometallics, Vol. 26, No. 8, 2007 1923
the data showed negligible decay during data collection; the data
were processed with SADABS and corrected for absorption. The
structure was solved and refined with the Bruker SHELXTL
(version 6.12) software package, using the space group Pbca with
Z ) 8 for the formula C26H40PI3Ru. All non-hydrogen atoms were
refined anisotropically with the hydrogen atoms placed in idealized
positions. Full matrix least-squares refinement based on F2 con-
verged at R1 ) 0.0271 and wR2 ) 0.0807 [based on I > 2σ(I)],
R1 ) 0.0328 and wR2 ) 0.0828 for all data. Additional details
are presented in the Supporting Information.
Complex 25. Orange blocks of 25 were grown by vapor diffusion
of pentane into a dichloromethane solution at -35 °C. A crystal of
dimensions 0.44 × 0.40 × 0.28 mm was mounted on a standard
Bruker SMART 1K CCD-based X-ray diffractometer equipped with
a LT-2 low-temperature device and normal focus Mo-target X-ray
tube (λ ) 0.71073 A) operated at 2000 W power (50 kV, 40 mA).
The X-ray intensities were measured at 108(2) K; the detector was
placed at a distance 4.969 cm from the crystal. A total of 2645
frames were collected with a scan width of 0.5° in ω and φ with
an exposure time of 25 s/frame. The integration of the data yielded
a total of 229 661 reflections to a maximum 2θ value of 59.18° of
which 29 746 were independent and 22 201 were greater than 2σ-
(I). The final cell constants were based on the xyz centroids of 2048
reflections above 10σ(I). Analysis of the data showed negligible
decay during data collection; the data were processed with SADABS
and corrected for absorption. The structure was solved and refined
with the Bruker SHELXTL (version 6.12) software package, using
the space group P2(1)/c with Z ) 4 for the formula 2(C44H73P2-
Cl2Ru), 5(CH2Cl2), 2(BF4). All non-hydrogen atoms were refined
anisotropically with the hydrogen atoms placed in idealized
positions. Full matrix least-squares refinement based on F2 con-
verged at R1 ) 0.0590 and wR2 ) 0.1310 [based on I > 2σ(I)],
R1 ) 0.0853 and wR2 ) 0.1431 for all data. Additional details
are provided in the Supporting Information.
Bruker SMART CCD-based X-ray diffractometer equipped with a
LT-2 low-temperature device and normal focus Mo-target X-ray
tube (λ ) 0.71073 A) operated at 2000 W power (50 kV, 40 mA).
The X-ray intensities were measured at 123(2) K; the detector was
placed at a distance 4.980 cm from the crystal. A total of 2635
frames were collected with a scan width of 0.5° in ω and φ with
an exposure time of 30 s/frame. The integration of the data yielded
a total of 87 016 reflections to a maximum 2θ value of 51.18° of
which 9496 were independent and 6468 were greater than 2σ(I).
The final cell constants were based on the xyz centroids of 5578
reflections above 10σ(I). Analysis of the data showed negligible
decay during data collection; the data were processed with SADABS
and corrected for absorption. The structure was solved and refined
with the Bruker SHELXTL (version 6.12) software package, using
the space group P2(1)/c with Z ) 4 for the formula C44H73F2P2-
Cl2Ru‚(CD2Cl2)2. All non-hydrogen atoms were refined anisotro-
pically with the hydrogen atoms placed in idealized positions. Full
matrix least-squares refinement based on F2 converged at R1 )
0.0402 and wR2 ) 0.0816 [based on I > 2σ(I)], R1 ) 0.0828 and
wR2 ) 0.0950 for all data. Additional details are provided in the
Supporting Information.
Acknowledgment. S.R.C. is grateful to the University of
Michigan Chemistry Department for Margaret and Herman
Sokol and Robert W. Parry Inorganic Chemistry Graduate
Fellowships. This material is based upon work supported by
the National Science Foundation under Grant No. CHE-0449459
and by an award from Research Corporation. We also thank
the University of Michigan and the Camille and Henry Dreyfus
Foundation for support.
Supporting Information Available: Spectral data for 21 and
23-I and full crystallographic details for 19, 22, 25, and 26 in pdf
and cif formats. This material is available free of charge via the
Internet at http://pubs.acs.org.
Complex 26. Orange needles of 26 were crystallized from a
deuterated dichloromethane solution at -35 °C. A crystal of
dimensions 0.40 × 0.22 × 0.10 mm was mounted on a standard
OM061192V