Activation of alkynes by {[Cp*Ru(CO)(PMei Pr2)]+}: X-ray crystal structures of [Cp*Ru≡C≡CHtBu (CO)(PMeiPr2)][BAr4′ and [Cp*Ru(CO)2(PMeiPr2)][BAr4′]

Article abstract of DOI:10.1016/j.jorganchem.2004.05.029

The complex [Cp*Ru{OCMe₂) (PMeⁱ Pr₂)][BAr₄′](2, Ar₄′ = 3,5-C₆H₃(CF₃)₂) reacts with HC≡CPh at 40°C in CD₂Cl₂ furnishing the π-alkyne ad

Full text of DOI:10.1016/j.jorganchem.2004.05.029

Journal of Organometallic Chemistry 689 (2004) 2853–2859
www.elsevier.com/locate/jorganchem
Activation of alkynes by {[Cp*Ru(CO)(PMeiPr2)]+}: X-ray 0
crystal structures of ½CpꢀRu@C@CHtBuðCOÞðPMeiPr2Þꢁ½BAr4ꢁ
and ½CpꢀRuðCOÞ ðPMeiPr2Þꢁ½BAr04ꢁ
Manuel Jimenez-Tenorio, M. Dolores Palacios, M. Carmen Puerta, Pedro Valerga
2
*
´
´ ´ ´ ´ ´
Departamento de Ciencia de los Materiales e Ingenierıa Metalurgica y Quımica Inorganica, Facultad de Ciencias, Universidad de Cadiz,
´
Apartado 40, 11510 Puerto Real (Cadiz), Spain
Received 19 April 2004; accepted 24 May 2004
Available online 20 July 2004
Dedicated to Prof. J.J. Vicente Soler (Universidad de Murcia, Spain) on the occasion of his 60 birthday
Abstract
The complex ½CpꢀRufOCMe2gðCOÞðPMeiPr2Þꢁ½BAr04ꢁð2; Ar04 ¼ 3; 5 ꢂ C6H3ðCF3Þ Þ reacts with HC„CPh at ꢂ40 °C in CD2Cl2
2
furnishing the p-alkyne adduct ½CpꢀRuðg2-HCBCPhÞðCOÞðPMeiPr2Þꢁ½BAr04ꢁ (3), which rearranges to the vinylidene complex
½CpꢀRu@C@CHPhðCOÞðPMeiPr2Þꢁ½BAr40 ꢁ (4a) when the temperature is raised to 25 °C. ½CpꢀRu@C@CHRðCOÞðPMeiPr2Þꢁ½BAr04ꢁ
(R=Ph 4a, Bu4b, H 4c) were obtained by reaction of [Cp*RuCl(CO)(PMeiPr2)] (1) with NaBAr04 and alkyne in fluorobenzene.
t
Addition of water to the vinylidene complexes leads to the dicarbonyl ½CpꢀRuðCOÞ ðPMeiPr2Þꢁ½BAr40 ꢁ (5), whereas deprotonation
2
yields neutral r-alkynyl complexes [Cp*Ru(C„CR)(CO)(PMeiPr2)] (R=tBu 6b,
H 6c). The allenylidene complex
½CpꢀRu@C@C@CPh2ðCOÞðPMeiPr2Þꢁ½BAr0 ꢁ (7) was prepared by reaction of 1 with HC„CC(OH)Ph2 and NaBAr0 in fluorobenzene.
4
4
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: p-alkyne complexes; Vinylidene complexes; Allenylidene complexes
1. Introduction
plexes. Our research group has reported very recently the
isolation and structural characterization of three isomers
of the acetylene adduct [Cp*Ru(C2H2)(PEt3)2][BPh4],
namely the g2-acetylene, hydridoacetylide and vinyli-
dene forms [10]. DFT and QM/MM calculations per-
formed, respectively, for the systems [CpRu(C2H2)-
(PH3)2]+ and [Cp*Ru(C2H2)- (PEt3)2]+ have shown that
Cp*, a better p-donor than Cp, and basic, strong elec-
tron-releasing phosphines stabilize the hydridoacetylide
form. Besides, bulky alkyl substituents at the phosphorus
atom contribute to the destabilization of the p-alkyne
form due to the increased steric repulsions [10].
The activation of alkynes by transition metal com-
plexes continues attracting a great deal of attention.
The involvement of transition metal vinylidene and al-
lenylidene complexes in the stoichiometric and catalytic
transformations of alkynes is well established [1–4]. We
have previously reported the isolation of metastable
half-sandwich RuIV alkynylhydrido complexes of the
type [Cp*RuH(C„CR)(P)2]+ ((P)2 =1,2-bis(diisopropyl-
phosphino)ethane (dippe) [5,6], (PEt3)2 [7,8], (PMeiPr2)2
[9]) as intermediates in the formation of vinylidene com-
Hydroxyalkynylhydrido complexes have been also
characterized as intermediate species in the formation of
hydroxyvinylidenecomplexes, whichbysubsequentdehy-
dration alternatively lead to allenylidene, vinylvinylidene
*
Corresponding author. Tel.: +34-956-016340; fax: +34-956-
016288.
E-mail address: pedro.valerga@uca.es (P. Valerga).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.05.029

´
M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2854
or hydrido-enynyl derivatives [5–9,11]. In the context
of our studies in the chemistry of pentamethylcyclo-
pentadienylruthenium complexes, we have recently re-
ported the complexes [Cp*RuCl(CO)(PMeiPr2)] and the
cationic acetone adduct [Cp*Ru{OC(CH3)2}(CO)-
(PMeiPr2)]+ [12]. In this work we report the outcome of
our investigations on the activation of alkynes by the frag-
ment {[Cp*Ru(CO)(PMeiPr2)]+}. Here, we compare the
results with those previously obtained with the
{[Cp*Ru(P)2]+} ((P)2 =dippe [6,7,11], (PEt3)2 [7,8,10],
(PMeiPr2)2 [9]) fragments and the analogous less electron
rich {[CpRu(CO)(PiPr3)]+} fragment [13].
amount of the corresponding alkyne was added. After ad-
dition of NaBAr04 (206 mg, 0.23 mmol) the mixture was
stirred for 30 min at room temperature and then filtered
through celite. The solution was layered with petroleum
ether. The resulting crystalline solids were filtered off,
washed with petroleum ether and dried in vacuo.
2.3.1. Compound 4a
Yield: 240 mg, 75%. Anal. Calc. for C58H50BF24O-
PRu: C, 51.1; H, 3.70. Found: C, 51.4; H, 3.75%. IR
1
(Nujol): m(CO) 2011 (s) cmꢂ1, m(C‚C) 1659 cmꢂ1. H
NMR (400 MHz, CDCl3, 298 K): d 0.98 and 1.13 (m,
12 H, PCH(CH3)2), 1.52 (d, 3 H, JHP =8.9 Hz,
2
PCH3), 2.06 (m, 2 H, PCH(CH3)2), 1.90 (d, 15 H,
4
2. Experimental
4JHP =1.2 Hz, C5(CH3)5), 6.04 (d, JHP =2.5 Hz, 1 H,
(C‚CHPh), 6.97, 7.24 and 7.33 (m, 5 H, Ph); 31P{1H}
NMR (161.89 MHz, CDCl3, 298 K): d 51.56 (s);
13C{1H} NMR (75.4 MHz, CDCl3, 298 K) d: 9.75 (d,
1JCP =24.0 Hz, PCH3), 10.45 (s, C5(CH3)5), 17.43,
2.1. General consideration
All synthetic operations were performed under a dry
dinitrogen or argon atmosphere, using conventional
Schlenk techniques. Tetrahydrofuran, diethyl ether and
petroleum ether (boiling point range 40–60 °C) were dis-
tilled from the appropriate drying agents. Fluorobenzene
was purchased from Aldrich (0.01% water max.). All sol-
vents were deoxygenated immediately before use. The
complexes [Cp*RuCl(CO)(PMeiPr2)] 1 and ½CpꢀRu
1
17.70 and 18.26 (m, PCH(CH3)2), 27.27 (d, JCP =27.6
Hz, PCH(CH3)2), 28.44 (d, 1JCP =26.9 Hz, PCH(CH3)2),
3
106.57 (s, C5(CH3)5), 117.87 (d, JCP =2.0 Hz,
Ru‚C‚CHPh), 122–133 (s, Ph), 199.22 (d,
2
2JCP =16.7 Hz, CO), 369.03 (d, JCP =15.1 Hz, Ru‚C).
2.3.2. Compound 4b
Yield: 200 mg, 65%. Anal. Calc. for C56H54BF24O-
PRu: C, 50.1; H, 4.06. Found: C, 50.4; H, 4.11%. IR
fOCðCH3Þ gðCOÞðPMeiPr2Þꢁ½BAr40 ꢁð2; Ar04¼ 3; 5 ꢂ C6H3
2
ðCF3Þ Þwerepreparedaccordingtorecentlyreportedpro-
2
1
cedures [12]. IR spectra were recorded in Nujol mulls on a
Perkin–Elmer Spectrum 1000 spectrophotometer. NMR
spectra were taken on a Varian Unity 400 MHz or a Var-
ian Gemini 300 MHz spectrometer. Chemical shifts are
given in ppm from SiMe4 (1H and 13C{1H}), or 85%
H3PO4 (31P{1H}). Microanalyses were performed by the
(Nujol): m(CO) 2001 (s) cmꢂ1, m(C‚C) 1674 cmꢂ1. H
NMR (400 MHz, CDCl3, 298 K): d 0.92 and 1.09 (m,
12 H, PCH(CH3)2), 1.13 (s, 9 H, C(CH3)3), 1.47 (d, 3
2
H, JHP =8.9 Hz, PCH3), 1.96 and 2.05 (m, 2 H, PCH
4
(CH3)2), 1.90 (d, 15 H, JHP =1.4 Hz, C5(CH3)5), 4.84
4
(d, JHP =2.5 Hz, 1 H, (C‚CHBut); 31P{1H} NMR
(161.89 MHz, CDCl3, 298 K): d 49.97 (s); 13C{1H}
NMR (75.4 MHz, CDCl3, 298 K) d: 8.35 (d,
1JCP =34.8 Hz, PCH3), 10.42 (s, C5(CH3)5), 17.14,
17.38, 17.70 and 18.33 (s, PCH(CH3)2), 27.15 (d,
´
Serveis Cientıfico-Tecnics, Universitat de Barcelona.
`
2.2. Characteri0zation of [CpꢀRu(g2-HCBCPh)(CO)
(PMeiPr2)][BAr4] (3)
1
1JCP =27.9 Hz, PCH(CH3)2), 28.42 (d, JCP =28.1 Hz,
½CpꢀRufOCðCH3Þ gðCOÞðPMeiPr2Þꢁ½BAr04ꢁ 2 (ca. 70
PCH(CH3)2), 31.67 (s, C(CH3)3), 33.67 (s, C(CH3)3),
3
106.57 (s, C5(CH3)5), 124.73 (d, JCP =2.0 Hz,
2
mg) was dissolved in CD2Cl2 in a NMR tube. The solu-
tion was cooled to ꢂ40 °C using an ethanol bath cooled
with liquid N2, then an excess of alkyne was added. The
sample was inserted into the precooled NMR probe,
2
Ru‚C‚CHBut), 200.17 (d, CO, JCP =16.6 Hz),
2
359.28 (d, JCP =13.0 Hz, Ru‚C).
1
1
and H and 31P{1H} NMR spectra were recorded. H
2.3.3. Compound 4c
Yield: 200 mg, 65%. Anal. Calc. for C52H46BF24O-
PRu: C, 48.6; H, 3.61. Found: C, 48.7; H, 3.71%. IR
NMR (400 MHz, CD2Cl2, 233 K): d 0.95–1.2 (m, 15 H,
PCH(CH3)2, PCH3), 1.67 (d, 15 H, JHP =1.1 Hz,
C5(CH3)5), 2.04 (m, 2 H, PCH(CH3)2), 4.65 (d, 1 H,
3JHP =13.7 Hz, HC„CPh), 7.32–7.61 (m, 5 H, Ph);
31P{1H} NMR (161.89 MHz, CD2Cl2, 233 K): d 42.13 (s).
4
1
(Nujol): m(CO) 2016 (s) cmꢂ1, m(C‚C) 1633 cmꢂ1. H
NMR (400 MHz, CDCl3, 298 K): d 0.95 and 1.09 (m,
12 H, PCH(CH3)2), 1.46 (d, 3 H, JHP =8.8 Hz,
2
PCH3), 2.01 (m, 2 H, PCH(CH3)2, 1.89 (br, 15 H,
4
2.3. Synthesis of [CpꢀRu@C@CHR(CO)(PMeiPr2)][BAr04]
(R=Ph (4a), Bu (4b), H (4c))
C5(CH3)5), 4.33 (d, JHP =2.9 Hz, 2 H, (C‚CH2);
31P{1H} NMR (161.89 MHz, CDCl3, 298 K): d 51.13
(s); 13C{1H} NMR (75.4 MHz, CDCl3, 298 K) d: 9.35
(d, JCP =33.3 Hz, PCH3), 10.26 (s, C5(CH3)5), 17.10,
t
1
To a solution of [Cp*RuCl(CO)(PMeiPr2)] 1 (100 mg,
0.23 mmol) in fluorobenzene (8 ml), the stoichiometric
17.20, 17.70 and 17.98 (s, PCH(CH3)2), 27.48 (d,

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M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2855
1
1JCP =27.2 Hz, PCH(CH3)2), 28.02 (d, JCP =28.7 Hz,
2.5.2. Compound 6c
Yield: 40 mg, 65%. Anal. Calc. for C20H33OPRu: C,
56.9; H, 7.89. Found: C, 58.8; H, 7.80%. IR (Nujol):
.
m(CO) 1996 (s) cmꢂ1, m(C„C) 2050 cmꢂ1 1H NMR
3
PCH(CH3)2), 96.3 (d, JCP =1.8 Hz, C‚CH2) 105.6 (s,
C5(CH3)5), 198.9 (d, JCP =15.9 Hz, CO), 356.25 (d,
2
2JCP =12.3 Hz, Ru‚C).
(400 MHz, C6D6, 298 K): d 0.96 (m, 12 H, PCH(CH3)2),
1.06 (d, 3 H, JHP =8.4 Hz, PCH3), 1.70 (m, 2 H,
2
2.4. Synthesis of [CpꢀRu(CO)2(PMeiPr2)][BAr04] (5)
PCH(CH3)2), 1.73 (s, 15 H, C5(CH3)5), 2.74 (d,
4JHP =0.71 Hz, 1 H, (RuC„CH); 31P{1H} NMR
(161.89 MHz, C6D6, 298 K): d 47.70 (s); 13C{1H}
Carbon monoxide was bubbled through a solution of
1 (80 mg, 0.2 mmol) in fluorobenzene (8 ml) and a slight
excess of NaBAr04 was added. The mixture was stirred
for 1 h. Removal of solvent until half-volume and layer-
ing with petroleum ether, afforded a microcrystalline
white solid. Single crystals adequate for X-ray diffrac-
tion study were obtained by recrystallization from
Et2O/petroleum ether. Yield: 200 mg, 65%. Anal. Calc.
for C51H44BF24O2PRu: C, 47.6; H, 3.44. Found: C,
46.7; H, 3.47%. IR (Nujol): m(CO) 2001 (s) cmꢂ1, 2047
1
NMR (75.4 MHz, C6D6, 298 K) d: 9.12 (d, JCP =24.8
Hz, PCH3), 10.46 (s, C5(CH3)5), 18.10, 18.56, 18.65,
1
19.02 (s, PCH(CH3)2), 25.87 (d, JCP =21.5 Hz,
1
PCH(CH3)2), 27.87 (d, JCP =21.5 Hz, PCH(CH3)2),
83.01 (s, RuC„C), 97.8 (s, C5(CH3)5), 117.74 (d,
2JCP =22.1 Hz, RuC„C), 202.5 (d, 2JCP =17.7 Hz, CO).
2.6. Synthesis of [CpꢀRu@C@C@CPh2(CO)(PMeiPr2)]
[BAr04] (7)
1
cmꢂ1. H NMR (400 MHz, CDCl3, 298 K): d 1.08 (m,
2
12 H, PCH(CH3)2, 1.37 (d, 3 H, JHP =8.5 Hz, PCH3),
Solid NaBAr04 (150 mg, 1.67 mmol) was added to a
solution of compound 1 (720 mg, 1.67 mmol) and 1,1-
diphenylpropyn-1-ol (350 mg, 1.7 mmol) in 10 ml of flu-
orobenzene. The mixture was stirred for 8 h at room
temperature and the colour changed from yellow-orange
to dark purple. The solution was filtered through celite
and the solvent was removed in vacuo. The residue
was dissolved in methanol and the solvent was evaporated
to dryness. The solid was washed with petroleum ether
affording a dark purple solid. Yield: 1.9 g, 80%. Anal.
Calc. for C65H54BF24OPRu: C, 53.8; H, 3.75. Found:
4
2.06 (m, 2 H, PCH(CH3)2), 1.91 (d, JHP =1.5 Hz, 15
H, C5(CH3)5); 31P{1H} NMR (161.89 MHz, CDCl3,
298 K): d 45.08 (s); 13C{1H} NMR (75.4 MHz, CDCl3,
1
298 K) d: 10.74 (d, JCP =32.1 Hz, PCH3), 10.77 (s,
C5(CH3)5), 17.88, 18.44 (s, PCH(CH3)2), 28.20 (d,
1JCP =27.2 Hz, PCH(CH3)2), 103.29 (s, C5(CH3)5),
2
198.68 (d, JCP =14.63 Hz, CO).
2.5. Synthesis of [CpꢀRu(CBCR)(CO)(PMeiPr2)]
(R ¼ tBu(6b), H(6c))
To a solution of the corresponding vinylidene com-
plex 4b or 4c (200 mg in 5 ml of THF) a slight excess
of KOtBu was added. After stirring the mixture for 3
h at room temperature, the colour changed from orange
to yellow. The solvent was removed in vacuo, and the
residue extracted with 10 ml of petroleum ether. The so-
lution was filtered through celite, concentrated to ca. 1
ml and cooled to ꢂ20 °C. The resulting microcrystalline
solid was filtered off and dried in vacuo.
C, 53.7; H, 3.85%. IR (Nujol): m(CO) 1936 (s) cmꢂ1
,
1
m(C‚C‚C) 2004 cmꢂ1. H NMR (400 MHz, CDCl3,
298 K): d 1.05 (m, 12 H, PCH(CH3)2), 1.36 (d, 3 H,
2JHP =8.9 Hz, PCH3), 2.04 (m, 2 H, PCH (CH3)2),
4
1.95 (d, 15 H, JHP =1.1 Hz, C5(CH3)5), 7.42 and 7.71
(m, 10 H, Ph); 31P{1H} NMR (161.89 MHz, CDCl3,
298 K): d 53.11 (s); 13C{1H} NMR (75.4 MHz, CDCl3,
1
298 K) d: 7.8 (d, JCP =25.9 Hz, PCH3), 10.51 (s,
C5(CH3)5,), 17.89 (d, JCP =19.9 Hz, PCH(CH3)2),
2
2
17.16 (d, JCP =23.6 Hz, PCH(CH3)2), 27.4 (d,
1
2.5.1. Compound 6b
Yield: 50 mg, 68%. Anal. Calc. for C24H41OPRu: C,
60.3; H, 8.65. Found: C, 60.5; H, 8.70%. IR (Nujol):
1JCP =27.4 Hz, PCH(CH3)2), 27.7 (d, JCP =27.4 Hz,
PCH(CH3)2), 104.5 (s, C5(CH3)5), 129.3, 131.6 and
3
133.5 (s, Ph), 141.8 (s, Cc), 186.8 (d, JCP =2.4 Hz,
2
2
(CO) 2006 (s) cmꢂ1, m(C„C) 2070 cmꢂ1
.
1H NMR
Cb), 201.5 (d, JCP =17.6 Hz, CO), 289 (d, JCP =15.8
Hz, Ca).
(400 MHz, C6D6, 298 K): d 0.93 and 1.18 (m, 12 H,
PCH(CH3)2), 1.30 (d, 3 H, JHP =8.0 Hz, PCH3), 1.42
2
(s, 9 H, C(CH3)3, 1.82 (m, 2 H, PCH(CH3)2), 1.77 (d,
4JHP =1.3 Hz, 15 H, C5(CH3)5); 31P{1H} NMR (161.89
MHz, C6D6, 298 K): d 50.05 (s); 13C{1H} NMR (75.4
2.7. X-ray structure determinations
Crystals of 4b and 5 were obtained by recrystalliza-
tion from ethyl ether/petroleum ether. Crystal data
and experimental details are given in Table 1. X-ray dif-
fraction data were collected on a Bruker SMART APEX
3-circle diffractometer with CCD area detector at the
1
MHz, C6D6, 298 K) d: 9.12 (d, JCP =30.8 Hz, PCH3),
10.90 (s, C5(CH3)5), 17.47, 18.20, 18.72, 19.15 (s,
1
PCH(CH3)2), 26.68 (d, JCP =22.2 Hz, PCH(CH3)2),
1
28.33 (d, JCP =27.7 Hz, PCH(CH3)2), 29.73 (s,
3
C(CH3)3), 33.67 (s, C(CH3)3), 96.28 (d, JCP =2.3 Hz,
´
Servicio Central de Ciencia y Tecnologıa de la Univers-
´
2
C5(CH3)5), 113.7 (s, RuC„C), 90.54 (d, JCP =23.6
idad de Cadiz. Hemispheres of the reciprocal space were
measured by omega scan frames with d(x) 0.30°.
2
Hz, RuC„C), 208.8 (d, JCP =19.7 Hz, CO).

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M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2856
Table 1
Crystal data and details of structure determination for compounds 4b
and 5
NMR spectroscopy. The proton of the p-alkyne ligand
appears as one doublet at 4.65 ppm in the H NMR
1
spectrum, whereas the 31P{1H} consists of one singlet
at 42.13 ppm. When temperature is raised up to 25 °C,
these resonances disappear, being replaced by new sig-
nals, respectively, at 6.04 ppm in the 1H NMR spectrum
and at 51.56 ppm in the 31P{1H} NMR spectrum. This
indicates transformation of the p-alkyne into the vinyl-
idene complex ½CpꢀRu@C@CHPhðCOÞðPMeiPr2Þꢁ
½BAr04ꢁ (4a).
Compound
4b
5
Formula
C56H54BF24OPRu
1341.84
Triclinic
C51H44BF24O2PRu
1287.71
Triclinic
Formula weight
Crystal system
Space group
ꢀ
ꢀ
P1 (No. 2)
P1 (No. 2)
Unit cell dimensions
˚
a (A)
˚
12.8742(7)
12.9394(7)
19.396(1)
79.822(1)
74.193(1)
88.168(1)
3059.5(3)
2
12.5835(9)
12.731(1)
18.854(1)
81.842(2)
74.481(2)
80.988(2)
2858.4(4)
2
b (A)
˚
c (A)
a (°)
b (°)
c (°)
3
˚
V (A )
Z
d (calc) (g/cm3)
1.457
0.392
1356
1.496
0.418
1292
l(Mo Ka) (mmꢂ1
F(000)
)
˚
k (A)
Mo Ka 0.71073
1.6, 25.1
Mo Ka 0.71073
1.6, 24.0
23,893, 10,692, 0.030 22,471, 8932, 0.047
hminꢂhmax (°)
Total, unique, Rint
Observed (I>2rI)
Reflections, parameters 10,692, 994
9302
6637
8932, 897
0.0898, 0.1876
0.1203, 0.2047
1.04
R, wR2 (I>2rI)
R, wR2 (all)
Goodness-of-fit
0.0877, 0.1945
0.1000, 0.2031
1.12
3
˚
Residuals (e/A )
ꢂ0.78, 1.93
ꢂ0.52, 0.79
At variance with the related systems containing two
phosphine ligands [5–9], in this case there is no evidence
for the formation of a RuIV hydrido-alkynyl complex as
intermediate in the alkyne to vinylidene tautomeriza-
tion. This reflects the important change in the electron
richness, and in hence, in the reactivity of the metal cen-
tre when replacing one bulky, strong electron-releasing
phosphine ligand by the much smaller, p-acceptor CO li-
gand. Therefore, in this system the formation of vinyli-
dene complexes occurs most likely through a direct
1,2-H shift [4].
The vinylidene complexes ½CpꢀRu@C@CHRðCOÞ
ðPMeiPr2Þꢁ½BAr04ꢁ (R=Ph 4a, tBu 4b, H 4c) were isolated
as crystalline solids by reaction of [Cp*RuCl(CO)(P-
MeiPr2)] 2 with NaBAr04 in fluorobenzene in the presence
of alkyne. As it has been observed in other instances, the
primary vinylidene complex 4c was most likely generated
by desilylation of the trimethylsilylvinylidene derivative
[Cp*Ru‚C‚CHSiMe3(CO)(PMeiPr2)]+, which was
not isolated. Attempts to generate 4c by direct reaction
of 2 with NaBAr04 in fluorobenzene under acetylene failed.
The binuclear complex ½fCpꢀRuðCOÞðPMeiPr2Þg2
ðl-ClÞꢁ½BAr04ꢁ [12], which competes with the formation
of the vinylidene species, was isolated from this reaction.
The most characteristic spectral features of these com-
plexes are the resonances for the proton attached to Cb
in their 1H NMR spectra, and the resonances for the car-
bon atom bound to ruthenium Ca in their 13C{1H} NMR
spectra. These signals appear in the range expected for vi-
nylidene complexes. However, compared to similar com-
plexes containing two phosphine ligands, their positions
Correction for absorption and crystal decay (insignifi-
cant) were applied by semi-empirical method from
equivalents using program SADABS [14]. The structures
were solved by direct methods, completed by subsequent
difference Fourier synthesis and refined on F2 by full ma-
trix least-squares procedures using the program SHEL-
XTL [15]. All non hydrogen atoms were refined with
anisotropic displacement coefficients. CF3 groups of
the ½BAr04ꢁꢂ anion showed orientation disorder in these
compounds. All CF3 groups were refined as pairs of
CF3 with complementary orientations for compound
4b, and 7 of 8 groups for compound 5. One methyl
group (corresponding to C46) in the phosphine ligand
of 5 also showed disorder which was not modelled. All
the remaining hydrogen atoms in both compounds were
refined using the SHELX riding model. The program OR-
TEP-3 [16] was used for plotting.
CCDC reference numbers 232973 and 232974.
3. Results and discussion
Scheme 1 summarizes the alkyne activation reactions
discussed here. The acetone adduct ½CpꢀRufOCMe2g
31
ðCOÞðPMeiPr2Þꢁ½BAr04ꢁ 2 reacts with phenylacetylene
in CD2Cl2 at ꢂ40 °C furnishing the p-alkyne complex
½CpꢀRuðg2-HCBCPhÞðCOÞðPMeiPr2Þꢁ½BAr04ꢁ (3), which
was characterized in solution by 1H and 31P{1H}

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M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2857
Scheme 1. Summary of alkyne activation reactions by compound 1.
appear shifted to lower fields, as a result of the decreased
electron density at the metal centre. The crystal structure
of 4b was determined. An ORTEP view of the complex
cation [Cp*Ru‚C‚CHtBu(CO)(PMeiPr2)]+ is shown
in Fig. 1, together with a listing of selected bond lengths
and angles.
The complex has a pseudo-octahedral three-legged
piano stool structure, similar to that observed for other
half-sandwich vinylidene complexes. The Ru1–C11
˚
bond distance of 1.880(6) A corresponds to a Ru‚C
double bond, but it appears slightly longer than
[Cp*Ru‚C‚CHCOOMe(dippe)][BPh4] (1.807(9) A)
˚
[5] and in other half-sandwich bis(phosphine) vinylidene
complexes, which have Ru‚C bond lengths in the range
˚
1.76–1.85 A [4]. The value of 178.8(6)° for the Ru1–
C11–C12 angle is consistent with the linearity of the
vinylidene ligand. Interestingly, very few vinylidene ru-
thenium half-sandwich compounds containing CO have
been actually isolated, i.e., [Cp*Ru‚C‚CHPh(CO)-
(PCy2CH2CH2OMe)][BPh4] [17]. The protonation
of the alkynyl complex [CpRu(C„CPh)(CO)(PPh3)]
with HBF4 at ꢂ80 °C in CD2Cl2 yields quantita-
tively the cationic vinylidene complex [CpRu‚C‚
CHPh(CO)(PPh3)]+, but it converts into an equilibrium
mixture of the vinylidene (9%) plus the p-alkyne adduct
[CpRu(g2-HC„CPh)(CO)(PPh3)]+ (91%) when the
temperature is raised to 25 °C [18]. On the other hand,
Bruce and co-workers [19] have reported that the forma-
tion of the alkoxy-carbene derivatives [CpRu‚C(OR)-
Fig. 1. ORTEP diagram of the cation [Cp*Ru‚C‚CHtBu(CO)
(PMeiPr2)]+ in compound 4b. Selected bond distances (A) and angles
˚
(°): Ru1–C11 1.880(6); Ru1–C17 1.875(7); Ru1–P1 2.349(2); C11–C12
1.273(9); C12–C13 1.52(1); Ru1–C11–C12 178.8(6); C11–C12–C13
128.1(7); C11–Ru1–P1 86.4(2); C17–Ru1–C11 91.1(3).
i
CH2Ph(CO)(PPh3)]+ (R=Me, Et, Pr) by protonation
of [CpRu(C„CPh)(CO)(PPh3)] with HPF6 in ROH
is mediated by the vinylidene complex [CpRu‚C‚
CHPh(CO)(PPh3)]+, but this was never isolated.
Clearly, the ability of the moieties {[CpRu(CO)(P)]+}

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M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2858
to stabilize vinylidene ligands is not as good as that of
their bis(phosphine) counterparts {[CpRu(P)2]+}.
The transformation of vinylidene ligands into car-
bonyl groups by the effect of moisture has been reported
[11,20,21]. The reactions of 2 with NaBAr04 and 1-hexyne
or HC„CCOOMe in fluorobenzene led to mixtures
containing the corresponding vinylidene complexes
and the dicarbonyl derivative ½CpꢀRuðCOÞ ðPMeiPr2Þꢁ
2
½BAr04ꢁ (5). Upon stirring the reaction mixtures at room
temperature for several hours all of the remaining vinyl-
idene complexes have been converted into the dicarbonyl
derivative 5. This process also has been observed in the
reactions with HCCPh, HC„CtBu or HC„CSiMe3,
but seems to take place much slower, allowing the isola-
tion of the pure vinylidene complexes. The source of
water is most likely that present in the halide scavenger
NaBAr04. Thus, when this salt is thoroughly dried by
prolonged pumping in vacuo at 80 °C, the moisture con-
tent is much lower and hence mixtures with higher con-
tent of vinylidene complex are obtained. In any case,
and in comparison with the other vinylidene complexes
described in the present work, the vinylidene complexes
[Cp*Ru‚C‚CHR(CO)(PMeiPr2)]+ (R=nBu, COOMe,
not isolated due to the formation of the dicarbonyl com-
plex 5) display an enormous tendency to react with trac-
es of water present in the reaction mixture. Compound 5
is easily accessible by reaction of 2 with NaBAr04 under
CO in fluorobenzene. Its crystal structure was deter-
mined. An ORTEP of [Cp*Ru(CO)2(PMeiPr2)]+ view is
shown in Fig. 2.
Fig. 2. ORTEP diagram of the cation [Cp*Ru(CO)2(PMeiPr2)]+ in
˚
compound 5. Selected bond distances (A) and angles (°): Ru1–P1
2.363(2); Ru1–C11 1.921(8); Ru1–C12 1.87(1); C11–O1 1.11(1); C12–
O2 1.14(1); Ru1–C11–O1 174(1); Ru1–C12–O2 176.1(9); C11–Ru1–P1
88.4(3); C12–Ru1–P1 88.5(3); C12–Ru1–C11 91.4(4).
(P)2 =(PMeiPr2)2 [9]). In neutral ruthenium allenylidene
complexes (i.e., [Cp*Ru‚C‚C‚CPh2(Cl)(PPh3)] [2])
this band also appears below 1900 cmꢂ1, whereas the re-
lated derivative [CpRu‚C‚C‚CPh2(CO)(PiPr3)][BF4]
[23] displays the band at 2002 cmꢂ1.This indicates that 7
contains an electron-poor ruthenium centre due to the
presence of the carbonyl ligand in the coordination
sphere. As a result, the reactivity patterns of the allenylid-
ene complex 7 are expected to be remarkably different to
those of the Cp*Ru bis(phosphine) allenylidene deriva-
tives that we have studied in the past, but very close to
the reactivity patterns displayed by the electron-poor sys-
tem [CpRu‚C‚C‚CPh2(CO)(PiPr3)]+ [13]. The nucle-
ophilic addition reactions to the allenylidene complex 7
will be reported in a forthcoming paper.
The complex has a three-legged piano stool structure,
with bond lengths and angles in the range observed for
other ruthenium half-sandwich dicarbonyl derivatives
reported in the literature [22], being unexceptional.
As it is characteristic for cationic vinylidene complex-
es, the deprotonation of 4b–c using KOtBu as base led to
the neutral alkynyl derivatives [Cp*Ru(C„CR)(CO)-
(PMeiPr2)] (R=tBu 6b, H 6c). As expected, these com-
pounds display in their IR spectra one strong m(C„C)
band at 2050 and 2070 cmꢂ1, respectively.
The allenylidene0 complex ½CpꢀRu@C@C@CPh2
Acknowledgement
ðCOÞðPMeiPr2Þꢁ½BAr4ꢁ (7) was obtained by activation of
the hydroxyalkyne HC„CC(OH)Ph2 by
2 using
´
We thank the Ministerio de Ciencia y Tecnologıa
NaBAr04 in fluorobenzene. As it occurs in other cases pre-
viously reported, the process involves most likely the for-
mation of a hydroxyvinylidene intermediate [6–9,11]
which undergoes spontaneous dehydration affording the
dark purple allenylidene complex 7 (Scheme 1). The reso-
nance for the ruthenium-bound Ca atom of the allenylid-
ene ligand appears as one doublet at 289 ppm in the
13C{1H} NMR spectrum. This compound displays one
strong m(C‚C‚C) band at 2004 cmꢂ1 in its IR spectrum.
This absorption band appears shifted to higher wavenum-
bers than in the related bis(phosphine) complexes
[Cp*Ru‚C‚C‚CPh2(P)2]+ (1890 cmꢂ1 for (P)2 =dippe
[23]; 1907 cmꢂ1 for (P)2 =(PEt3)2 [7,8]; 1916 cmꢂ1 for
(DGICYT, Project BQU2001–4026 and grant
BES2002-1422 to M. Dolores Palacios) and the Conse-
´
´
´
jerıa de Educacion y Ciencia de la Junta de Andalucıa
(P.A.I. research group FQM188) for financial support,
and Johnson Matthey plc for generous loans of ruthenium
trichloride.
Appendix A. Supplementary material
Supplementary data associated with this article can
be found, in the online version at doi:10.1016/j.jorgan-
chem.2004.05.029.

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M. Jimenez-Tenorio et al. / Journal of Organometallic Chemistry 689 (2004) 2853–2859
2859
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[14] G.M. Sheldrick, SADABS, 2001 version, University of Go¨ttingen,
Germany.
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