Reactions of [H2Os3(CO)10] with conjugated diynes (RC2C2R′) containing nucleophilic oxygen in β position of a substituent (R = Ph, R′ = CH2OH, C(O)Ph; R = R′ = CMe2(OH))

Article abstract of DOI:10.1021/om0304107

Reactions of [H₂Os₃(CO)₁₀] with a series of diynes, RC₂C₂R′ (1: R = Ph, R′ = CH ₂OH; 2: R = Ph, R′ = C(O)Ph; 3: R = R′ = C(OH)Me ₂), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R′ substituents of 1 and 2 take part in intramolecular cyclization reactions to give [HOs ₃(CO)₁₀{μ-η¹:η²-PhCH ₂-(C=CH-C=CH-O)}] (5) and [HOs₃(CO) ₁₀{μ-η¹:η¹-Ph(C=CH-C=CO)CPh}] (6), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs₃(CO)₉(μ₃-η¹:η ³:η¹Ph(C=CH-C=C-O)CPh)] (7) with a closed C ₃Os₃ pentagonal pyramidal structure. Reaction of [H₂Os₃(CO)₁₀] with 3 does not lead to cyclization of the diyne; instead, the clusters [Os₃(CO) ₁₀{μ₃-η²-(RCH=CH-C₂R)}] (8) and [Os₃(CO)₁₀{μ₃-η²-(RC ₂C₂R)}] (9) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H₂Os ₃(CO)₁₀] with HOCH₂C₂C ₂CH₂OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters 5, 7, and 9 are presented.

Full text of DOI:10.1021/om0304107

Organometallics 2003, 22, 3455-3465
3455
Rea ction s of [H2Os3(CO)10] w ith Con ju ga ted Diyn es
(RC2C2R′) Con ta in in g Nu cleop h ilic Oxygen in â P osition
of a Su bstitu en t (R ) P h , R′ ) CH2OH, C(O)P h ;
R ) R′ ) CMe2(OH))
Sergey P. Tunik,* Vassily D. Khripoun, Irina A. Balova,*
Maxim E. Borovitov, and Ivan N. Domnin
Department of Chemistry, St. Petersburg University, Universitetskii pr., 26,
St. Petersburg, 198504, Russian Federation
Ebbe Nordlander*
Inorganic Chemistry, Chemical Center, Lund University, Box 124, SE-221 00 Lund, Sweden
Matti Haukka and Tapani A. Pakkanen
Department of Chemistry, University of J oensuu, P.O. Box 111, FIN-80101 J oensuu, Finland
David H. Farrar
Lash Miller Chemical Laboratories, University of Toronto, 80 St. George Street,
Toronto, Ontario, Canada M5S 3H6
Received J une 2, 2003
Reactions of [H2Os3(CO)10] with a series of diynes, RC2C2R′ (1: R ) Ph, R′ ) CH2OH; 2:
R ) Ph, R′ ) C(O)Ph; 3: R ) R′ ) C(OH)Me2), have been studied. It was found that upon
coordination to the triosmium cluster, the nucleophilic oxygens of the R′ substituents of 1
and 2 take part in intramolecular cyclization reactions to give [HOs3(CO)10{µ-η1:η2-PhCH2-
(CdCH-CdCH-O)}] (5) and [HOs3(CO)10{µ-η1:η1-Ph(CdCH-CdC-O)CPh}] (6), respec-
tively, both of which contain furan rings coordinated to the cluster core. On heating of the
latter compound, the furan moiety remains intact, but a carbonyl group dissociates from
the cluster, leading to the formation of [HOs3(CO)9(µ3-η1:η3:η1-Ph(CdCH-CdC-O)CPh)] (7)
with a closed “C3Os3” pentagonal pyramidal structure. Reaction of [H2Os3(CO)10] with 3 does
not lead to cyclization of the diyne; instead, the clusters [Os3(CO)10{µ3-η2-(RCHdCH-C2R)}]
(8) and [Os3(CO)10{µ3-η2-(RC2C2R)}] (9) are formed. Deuterium labeling of the starting
compounds has been used in the reaction of [H2Os3(CO)10] with HOCH2C2C2CH2OH in order
to investigate possible mechanisms of the cyclization reaction. The crystal and molecular
structures of clusters 5, 7, and 9 are presented.
In tr od u ction
Several studies have shown that coordination of diynes
to transition metal carbonyl clusters is often accompa-
nied by rearrangement of these ligands. Such rear-
rangements include C-C bond rupture,1,3 ligand
coupling,4,10,11,13,14 and intramolecular cyclization reac-
tions.7,12,14 Recent results have shown that a cyclized
diyne may be decoordinated from a cluster under the
Because of the synthetic usefulness of 1,3-conjugated
diynes, their reactions with transition metal clusters
have received increased attention in recent years.1-15
* Corresponding authors. (S.P.T.) Fax: 7 (812) 4286939. E-mail:
stunik@st1323.spb.edu. (E.N.) E-mail: Ebbe.Nordlander@inorg.lu.se.
(1) Deeming, A. J .; Felix, M. S. B.; Bates, P. A.; Hursthouse, M. B.
J . Chem. Soc., Chem. Commun. 1987, 461.
(2) Corrigan, J . F.; Doherty, S.; Taylor, N. J .; Carty, A. J . Organo-
metallics 1992, 11, 3160.
(9) Bruce, M. I.; Zaitseva, N. N.; Skelton, B. W.; White, A. H. J .
Organomet. Chem. 1997, 536, 93.
(10) Tunik, S. P.; Grachova, E. V.; Denisov, V. R.; Starova, G. L.;
Nikol’skii, A. B.; Dolgushin, F. M.; Yanovsky, A. I.; Struchkov, Y. T.
J . Organomet. Chem. 1997, 536, 339.
(3) Deeming, A. J .; Felix, M. S. B.; Nuel, D. Inor. Chim. Acta 1993,
213, 3.
(4) Corrigan, J . F.; Taylor, N. J .; Carty, A. J . Organometallics 1994,
13, 3778.
(5) Blenkiron, P.; Taylor, N. J .; Carty, A. J . J . Chem. Soc., Chem.
Commun. 1995, 327.
(11) Bruce, M. I.; Skelton, B. W.; White, A. H.; Zaitseva, N. N. J .
Organomet. Chem. 1998, 558, 197.
(12) Bruce, M. I.; Skelton, B. W.; White, A. H.; Zaitseva, N. N. Inorg.
Chem. Commun. 1998, 1, 134.
(6) Karpov, M. G.; Tunik, S. P.; Denisov, V. R.; Starova, G. L.;
Nikol’skii, A. B.; Dolgushin, F. M.; Yanovsky, A. I.; Struchkov, Y. T.
J . Organomet. Chem. 1995, 485, 219.
(7) Blenkiron, P.; Enright, C. D.; Taylor, N. J .; Carty, A. J .
Organometallics 1996, 15, 2855.
(8) Bruce, M. I.; Zaitseva, N. N.; Skelton, B. W.; White, A. H. Inorg.
Chim. Acta 1996, 250, 129.
(13) Low, P. J .; Enright, G. D.; Carty, A. J . J . Organomet. Chem.
1998, 565, 279.
(14) Lau, C. S.-W.; Wong, W.-T. J . Chem. Soc., Dalton Trans. 1999,
2511.
(15) Clarke, L. P.; Davies, J . E.; Raithby, P. R.; Shields, G. P.; Tunik,
S. P.; Krupenya, D. V.; Starova, G. L. J . Chem. Soc., Dalton Trans., in
press.
10.1021/om0304107 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 07/15/2003

3456 Organometallics, Vol. 22, No. 17, 2003
Tunik et al.
proper reaction conditions.16 The elucidation of the
reaction mechanisms that occur in these processes may
facilitate the development of new rational synthetic
strategies aimed at producing novel organic chemicals.
In previous papers,6,15,17 we have demonstrated that
conjugated diynes containing an electrophilic center in
the â position of a substituent readily rearrange to form
(coordinated) five-membered cycles in reactions with
[H2Os3(CO)10]. General mechanistic schemes have been
proposed15,17 in order to clarify the trend of the diynes
to form five-membered rings upon coordination and to
explain variations in coordination modes of the rear-
ranged diynes on the osmium triangle. It has been
shown that the cyclization proceeds via nucleophilic
attack of the â atom of a substituent on the coordinated
diyne chain to give five-membered nitrogen-containing
heterocycles17 or indenyl systems15 bound to the tri-
nuclear cluster cores in µ-η1:η2-, µ-η1:η1-, or µ3-η1:η2:η1-
modes. In the present study, reactions of [H2Os3(CO)10]
with three conjugated diynes, RC2C2R′ (1: R ) Ph, R′
) CH2OH; 2: R ) Ph, R′ ) C(O)Ph; 3: R ) R′ ) C(OH)-
Me2) are presented.
etry, which indicated 80% enrichment. The deuterated cluster
[D2Os3(CO)10] was obtained by direct reaction of gaseous D2
with [Os3(CO)10(NCMe)2] in dichloromethane at room temper-
ature, which gave ca. 50% deuterium enrichment of the
starting cluster.
Rea ction of [H2Os3(CO)10] w ith P h CtC-CtCCH2OH
(1). [H2Os3(CO)10] (250 mg, 0.29 mmol) and 1 (99 mg, 0.64
mmol) were dissolved in 10 cm3 of dichloromethane and left
overnight at room temperature. After removal of the solvent,
the residue was dissolved in a minimum amount of CHCl3 and
separated by preparative TLC using a hexane/chloroform
mixture (2:1, v/v). Orange, solid [HOs3(CO)10(µ-η1:η2-PhCH2Cd
CH-CdCH-O)] (5) was isolated as the main product (Rf 0.67,
98.2 mg, 33.3%). IR (CH2Cl2, cm-1): νCO 2104w, 2066vs, 2052s,
2018s, 2008m. 1H NMR (CDCl3): δ 7.37-6.73 (m, 5H, phenyl),
7.96, 6.27 (1H, 1H, protons of the furan ring), 3.92 (s, 2H, CH2),
-16.10 (s, 1H, µ-HOs). 13C{1H} NMR (CD2Cl2, 298 K): δ 183.8
(1CO), 179.1 (2CO), 177.8 (1CO), 173.7 (2CO), 173.1 (2CO),
169.1 (2CO); 163.0, 134.1, 137.5 (C(16), C(13), C(15), cf. Figure
1); 124-134 (7C: CH carbons of phenyl ring and C(12), C(14));
69.6 (s, CH2). FAB-MS (m/z): 1008 [M+] (Os3 ) 570) and [M+
- nCO], n ) 1-10. Anal. Calcd for C21H10O11Os3: C, 25.00;
H, 1.00. Found: C, 25.30; H, 1.17. Single crystals of 5 suitable
for X-ray analysis were grown by slow diffusion of heptane
into diethyl ether at 4 °C.
Rea ction of [H2Os3(CO)10] w ith P h CtC-CtC(CO)P h
(2). [H2Os3(CO)10] (50 mg, 0.06 mmol) and 2 (20 mg, 0.09
mmol) were dissolved in 5 cm3 of CH2Cl2 and stirred for 3 h at
room temperature. After removal of the solvent, the residue
was dissolved in a minimum amount of CH2Cl2 and separated
by preparative TLC using a hexane/dichloromethane mixture
(3:1, v/v) as eluant. Violet solid [HOs3(CO)10(µ-η1:η1-Ph(CdCH-
CdC-O)CPh)] (6) was isolated as the main product (Rf 0.6,
64 mg, 98.6%). IR (CH2Cl2, cm-1): νCO 2102m, 2054s, 2024m,
Exp er im en ta l Section
Gen er a l Com m en t s. The starting materials [H2Os3-
(CO)10],18 5-phenylpenta-2,4-diyne-1-ol (1), 4-phenylbutadiy-
nylphenyl ketone (2), and 2,7-dimethyl-3,5-octadiyne-2,7-diol
(3) were prepared according to published procedures.19 Com-
mercial 2,4-hexadiyne-1,6-diol (4) (Aldrich) was used as re-
ceived. D2 was purchased from AGA Gas. All reactions were
carried out under an atmosphere of dry, oxygen-free nitrogen
using solvents that were freshly distilled from appropriate
drying agents. Deuterated dichloromethane was carefully dried
over molecular sieves directly before the experiments with
deuterated compounds in order to avoid isotopic exchange
processes due to the adventitious presence of water. Blank
experiments in which individual deuterium-labeled compo-
nents of the reaction mixture were dissolved in dried CD2Cl2
showed no change in the deuterium enrichment during 12 h.
Infrared spectra were recorded using Nicolet Avatar 360 FTIR
and Specord M80 spectrometers. Electron impact and fast
atom bombardment (FAB+) mass spectra were obtained on
J EOL SX-102 and MX-1321 instruments; 3-nitrobenzyl alcohol
was used as a matrix and CsI as the calibrant. 1H NMR spectra
were recorded on Varian Unity 300 MHz and Bruker DX 300
spectrometers; 13C NMR spectra, on a Bruker AM 500 instru-
ment using the solvent resonance as an internal standard and
[Cr(acac)3] as relaxant. DEPT-135 spectra were used to assign
CH, CH2, and CH3 resonances. Thin-layer chromatography
was performed on commercial plates precoated with Merck
Kieselgel 60 to 0.5 mm thickness, and silica 5-40 mesh was
used for flash chromatography separation of the reaction
mixtures; the bands obtained are reported in order of elution.
Microanalyses were carried out in the Analytical Laboratories
of St. Petersburg State University and University of J oensuu.
Deu t er a t ion of 2,4-Hexa d iyn e-1,6-d iol a n d [H2Os3-
(CO)10]. To prepare deuterium-enriched 2,4-hexadiyne-1,6-diol
(4) (in the OH positions), the diyne was dissolved in CD3OD
and left overnight. The solvent was then removed and the
deuterium enrichment was controlled by EI mass spectrom-
1
2010m, 1842w. H NMR (CDCl3): δ 7.82-7.28 (m, 11H, two
phenyl rings and CH of the furan system), -14.86 (s, 1H,
µ-HOs). FAB-MS (m/z): 1082 [M+] (Os3 ) 570) and [M+
-
nCO], n ) 1-10. 13C{1H} (CDCl3, 298 K): δ 211.1 (µ-CO);
190.5, 184.7, 184.5, 182.5, 178.9, 178.4, 177.9, 177.1, 174.4
(nine terminal CO); 173.9, 172.5, 172.3, 167.8 (three carbons
of the furan ring and C(Ph)); 152.5, 127.3 (ipso-C of two phenyl
rings); 129.4 (2C), 127.9 (2C), 127.7 (2C), 123.3 (2C) (ortho and
meta carbons of two phenyl rings); 129.3 (1C), 127.8 (1C) (para
carbons of two phenyl rings); 132.6 (1C) furan CH carbon. The
latter seven signals appear as positive phase resonances in
the DEPT-135 spectrum. Anal. Calcd for C27H12O11Os3: C,
29.94; H, 1.12. Found: C, 30.18; H, 1.42. Single crystals of 6
suitable for an X-ray analysis were grown by slow diffusion of
hexane in dichloromethane at -20 °C.
Th er m olysis of [HOs3(CO)10(µ2,η3-P h (CdCH-CdC-O)-
CP h )] (6). Compound 6 (30 mg) was refluxed in hexane for 3
h until a TLC spot test showed complete consumption of the
starting compound. Yellow, solid [HOs3(CO)9(µ3-η1:η3:η1-Ph(Cd
CH-CdC-O)CPh)] (7) was isolated as the only product of
reaction by preparative TLC, using a hexane/dichloromethane
mixture (4:1, v/v) as eluant (Rf 0.75, 29.0 mg, 99.2%). IR (CH2-
Cl2, cm-1): νCO 2100m, 2056s, 2024m, 2008m. 1H NMR
(CDCl3): δ 7.85-7.30 (m, 11H, two phenyl rings and CH of
the furan system), -19.59 (s, 1H, µ-HOs). FAB-MS (m/z): 1054
[M+] (Os3 ) 570) and [M+ - nCO], n ) 1-9. 13C{1H} (CDCl3,
298 K): δ 179.4 (1CO), 178.6 (1CO), 175.2 (1CO), 174.9 (3CO),
173.5 (1CO), 171.8 (2CO); 164.6 (C(12), cf. Figure 3); 147.9,
147.8, 146.2 (C(11), C(13), C(15)); 139.1 (C(16)); 129.1 (C(17));
131.7, 130.8, 129.4, 129.0, 128.4, 126.2, 121.5 (CH carbons of
two phenyl rings and C(14)). Anal. Calcd for C26H12O10Os3: C,
29.60; H, 1.15. Found: C, 29.80; H, 1.56. Single crystals of 7
suitable for X-ray analysis were grown from heptane at 25 °C.
Rea ction of [H2Os3(CO)10] w ith Me2(HO)C-CtC-Ct
C-C(OH)Me2 (3). [H2Os3(CO)10] (250 mg, 0.29 mmol) and 3
(98 mg, 0.59 mmol) were dissolved in 20 cm3 of dichlo-
romethane. IR spectroscopy indicated that the reaction was
(16) Raithby, P. R. University of Bath, private communication.
(17) Tunik, S. P.; Khripun, V. D.; Balova, I. A.; Nordlander, E.;
Haukka, M.; Pakkanen, T. A.; Raithby, P. R. Organometallics 2001,
20, 3854.
(18) Kaesz, H. D. Inorg. Synth. 1990, 28, 238.
(19) Brandsma, L.; Vasilevskii, S. F.; Verkruijsse, H. D. Application
of Transition Metal Catalysts in Organic Synthesis; Springer: Berlin,
1998.

Reactions of [H2Os3(CO)10]
Organometallics, Vol. 22, No. 17, 2003 3457
Ta ble 1. Cr ysta llogr a p h ic Da ta for [HOs3(CO)10(µ-η1:η2-P h CH2CdCH-CdCH-O)] (5),
[HOs3(CO)9(µ3-η1:η3:η1-P h (CdCH-CdC-O)CP h )] (7), a n d
[Os3(CO)10{µ3-η2-Me2((HO)C-CtC-CtC-C(OH)Me2}] (9)
5
7
9
empirical formula
fw
C
21H10O11Os3
C26H12O10Os3
1054.96
C26H20O12Os3
1095.02
1008.89
cryst size, mm
temperature, K
wavelength, Å
cryst syst, space group
a, Å
0.07 × 0.05 × 0.05
0.20 × 0.10 × 0.05
0.30 × 0.10 × 0.10
100(1)
120(2)
120(2)
0.71073
0.71073
0.71073
monoclinic, P21/n
9.3500(4)
22.1418(6)
11.5436(5)
90
100.337(2)
90
2351.03(16)
4, 2.850
triclinic, P1h
8.4266(2)
9.5776(3)
17.2474(5)
83.151(2)
83.457(2)
67.702(2
1275.12(6) (15)
2, 2.748
14510
orthorhombic, P212121
9.2706(1)
15.1508(4)
20.4703(5)
90
b, Å
c, Å
R, deg
â, deg
90
90
γ, deg
volume, Å3
2875.20(11)
4, 2.530
37545
6265
0.0596
Z, calcd density, Mg/m3
no. of reflns collected
no. of unique reflns
Rint
15820
4780
0.093
4452
0.0513
R1 [I > 2σ(I)]
wR2 [I > 2σ(I)]
largest diff peak and hole, e/Å-3
0.0368
0.0714
2.532 and -1.269
0.0391
0.1022
2.934 and -2.820
0.0225
0.0419
0.811 and -0.784
complete within 3 h. The obtained mixture was “preseparated”
using flash-chromatography (silica 5-40 mesh). Flash elution
with hexane/chloroform (1:1, v/v) gave a dark green band
containing a very unstable green compound, ca. 50 mg, which
could not be isolated in pure form, and minor decomposition
products. Further flash elution with pure chloroform gave a
mixture of two products, 8 and 9, which were separated by
preparative TLC (chloroform) into two bands and baseline. The
IR spectrum of the latter indicated that it contained no
carbonyl species, and it was therefore not investigated further.
Of the former two bands the first one (yellow, Rf 0.39) gave
orange-yellow,solid[Os3(CO)10(µ3-η2-Me2(HO)C-CHdCH-CtC-C-
(OH)Me2)] (8) (73 mg, 24.7%). IR (CH2Cl2, cm-1): νCO 2100w,
2062vs, 2044s, 2019m, 1994m. 1H NMR (CDCl3): δ 5.55 (d, 1J
0.3962 0.3324/0.1644, 0.5215/0.1537, and 0.3500/0.1088, re-
spectively). Structural refinements were carried out with the
SHELXTL v.5.1 or SHELXL97 programs.26 All organic hydro-
gens in 5, 6, 7, and 9, except the OH hydrogens in 9, were
constrained to ride on their parent atom. The OH hydrogens
were located from the difference Fourier map but not refined.
The hydride in 6 was located from a difference Fourier map
and refined isotropically. The hydride in 7 was placed in
idealized positions using the XHYDEX program.27 The struc-
ture of 9 was refined as a racemic twin (absolute structure
parameter 0.543(9)) in orthorhombic space group P212121. In
the structure of 6, a carbon in one of the carbonyls bonded to
Os was disordered. No acceptable disorder model was found
for this structure, which is included in the Supporting Infor-
mation.28 Crystallographic data for 5, 7, and 9 are summarized
in Table 1. Selected bond lengths and angles are shown in
Table 2, and the molecular structures in Figures 1, 4, and 6.
1
) 13 Hz) and 4.62 (d, J ) 13 Hz) vinylic protons; 3.39 (br s,
2H, OH); 1.41 (br s, 12H, CH3). 13C{1H} NMR (CD2Cl2, 298
K): δ 180-172 (a few broad resonances, CO), 162.0, 146.0,
142.6, 129.5 (diyne carbons), 80.9 (C(OH)Me2), 72.8 (C(OH)-
Me2), 30.9 (4CH3). FAB-MS (m/z): 1018 [M+] (Os3 ) 570) and
[M+ - nCO], n ) 1-3. Anal. Calcd for C20H16O12Os3: C, 23.57;
H, 1.58. Found: C, 23.28; H, 1.64. The second band (Rf 0.22)
gave orange, solid [Os3(CO)10(Me2(HO)C-CtC-CtC-C(OH)-
Me2)] (9) (91 mg, 30.9%). IR (CH2Cl2, cm-1): νCO 2102w,
2062vs, 2055s,sh, 2020m, 1998m,sh, 1840w,br. 1H NMR
(CDCl3): δ 3.08 (br s, 2H, OH), 1.48 (br s, 12H, CH3). 13C{1H}
NMR (CD2Cl2, 298 K): δ a broad resonance centered at ca.
176 (10 CO), 164.4, 115.2 (C(11), C(12)), 102.9, 93.4 (C(16),
C(17)), 80.1 (C(OH)Me2), 65.6 (C(OH)Me2), ca. 31.6 br (2CH3)
31.4 (2CH3). FAB-MS (m/z): 1016 [M+] (Os3 ) 570) and [M+
- nCO], n ) 1-10. Anal. Calcd for C20H14O12Os3: C, 23.62;
H, 1.39. Found: C, 23.56; H, 1.55. Single crystals of 9 suitable
for X-ray analysis were grown from benzene at 4 °C. An EI
mass spectrum of the reaction mixture showed the presence
of the following signals (m/z), which can be unambiguously
assigned to the free enyne Me2(HO)C-CHdCH-CtC-C(OH)-
Resu lts a n d Discu ssion
The reactions of [H2Os3(CO)10] with the conjugated
diynes PhC2C2CH2OH (1) and PhC2C2C(O)Ph (2), which
contain oxygen in â position of a substituent, result in
rearrangements of the diynes to give coordinated five-
membered heterocycles in a way that is very similar to
that found earlier for hexa-2,4-diyne-1,6-diol6 and some
nitrogen-containing diynes.17 Although Me2(HO)C-Ct
C-CtC-C(OH)Me2 (3) contains oxygen in â position
(20) COLLECT, data collection software; Nonius, B.V.: The Neth-
erlands, 1997-2000.
(21) Otwinowski, Z.; Minor, W. In Methods in Enzymology, Macro-
molecular Crystallography, part A; Carter, J ., C. W., Sweet, R. M., Eds.;
Academic Press: New York, 1997; Vol. 276, pp 307-326.
(22) Sheldrick, G. M. SHELXTL Version 5.1; Bruker AXS, Inc.:
Madison: WI, 1998.
Me2 and products of its fragmentation: 168 [M+], 153 [M+
-
CH3], 135 [M+ - CH3 - H2O].
(23) Sheldrick, G. M. SHELXS97, Program for Crystal Structure
Determination; University of Gottingen, 1997.
X-r a y Da ta Collection a n d Str u ctu r e Solu tion . The
X-ray diffraction data were collected with a Nonius Kappa
CCD diffractometer using Mo ΚR radiation (λ ) 0.71073 Å)
and the Collect20 program. The Denzo and Scalepack21 pro-
grams were used for cell refinements and data reduction. The
structures of 5, 6, and 9 were solved by direct methods using
the SHELXTL v.5.122 or SHELXS9723 program packages and
the WinGX24 graphical user interface. The structure of 7 was
solved by the Patterson method using the DIRDIF-99 pro-
gram.25 A multiscan absorption correction, based on equivalent
reflections, was applied to 5, 6, 7, and 9 (Tmax/Tmin were 0.4974/
(24) Farrugia, L. J . J . Appl. Crystallogr. 1999, 32, 837.
(25) Beurskens, P. T.; Beurskens, G.; de Gelder, R.; Garcia-Granda,
S.; Gould, R. O.; Israel, R.; Smits, J . M. M. The DIRDIF-99 program
system; Crystallography Laboratory, University of Nijmegen: The
Netherlands, 1999.
(26) Sheldrick, G. M. SHELXL97, Program for Crystal Structure
Refinement; University of Gottingen, 1997.
(27) Orpen, A. G. J . Chem. Soc., Dalton Trans. 1980, 2509.
(28) Crystal data for 6: C27H12O11Os3, monoclinic, a ) 9.9393(3) Å,
b ) 23.4588(4) Å, c ) 11.6438(4) Å, â ) 95.463(1)°, T ) 150(2), space
group P21/c, Z ) 4, Dc ) 2.662 cm-1, 31 506 reflections collected, 4820
unique (Rint ) 0.0849). The final R1 was 0.0415 [I > 2σ(I)], wR2(F2) )
0.1020 [I > 2σ(I)].

3458 Organometallics, Vol. 22, No. 17, 2003
Tunik et al.
F igu r e 1. ORTEP view of 5.
Ta ble 2. Selected Bon d Len gth s for Clu ster s 5, 7,
a n d 9a
ORTEP view of the molecule is shown in Figure 1, and
selected bond lengths and angles are given in Table 2.
The molecule consists of a closed Os3 triangle with 10
terminal CO ligands, a bridging hydride, and a substi-
tuted furan moiety derived from the diyne. The organic
furan ring is coordinated to an Os-Os edge in a
µ-η1:η2-mode. This σ-π coordination mode fits well to
the polyhedral skeleton electron pair theory (PSEPT)
view of bonding in a closed Os3 triangle;29 according to
this approach, the furan moiety contributes three
electrons to give the cluster a 48 valence electron count
and thus stabilizes the “HOs3(CO)10” fragment. The
main structural features of 5 are very similar to the
structural patterns found for its pyrrolyl analogues,
which contain µ-η1:η2-alkenyl coordinated ligands.17 The
Os-Os bond lengths in 5 range from 2.8449(5) to
2.8846(5) Å, the Os(1)-Os(2) bond spanned by the
furan moiety and the hydride being the shortest one.
It has been shown that the coordination of benzene to
a triosmium cluster results in considerable disruption
of the aromatic system, so that the bonding between the
benzene (“cyclohexatriene”) molecule and the metals
may be viewed as localized;30 in the same way, the
bonding between the furan moiety and the metals in 5
may be rationalized by a localized approach. Of the
three metal to carbon bonds between the alkenyl frag-
ment of the organic moiety and Os(1)/Os(2), the shortest
one is the (σ) Os(1)-C(13) bond, which is 2.155(10) Å.
The (π) bond between the C(13)dC(12) alkene fragment
and Os(2) atom is asymmetric due to the geometrical
constraints of the cyclic ligand: the Os(2)-C(13) and
Os(2)-C(12) distances are 2.375(9) and 2.566(9) Å,
respectively. However, it is worth noting that in 5 the
asymmetry is substantially lower than what is found
in the related clusters [HOs3(CO)10(µ-η1:η2-(PhCH2-
5
7
9
Os(1)-Os(2)
Os(1)-Os(3)
Os(2)-Os(3)
Os(1)-C(13)
Os(1)-C(12)
Os(2)-C(12)
Os(2)-C(13)
Os(2)-C(11)
Os(3)-C(11)
Os(3)-C(12)
Os(3)-C(13)
C(11)-C(12)
C(11)-C(16)
C(12)-C(13)
C(13)-C(14)
C(14)-C(15)
C(16)-C(17)
C(17)-C(18)
O-C(12)
2.8449(5)
2.8664(6)
2.8846(5)
2.155(10)
2.9899(4)
2.8325(4)
2.7925(4)
2.068(8)
2.8575(3)
2.8134(3)
2.7245(3)
2.164(6)
2.566(9)
2.375(9)
2.106(8)
2.345(7)
2.329(7)
2.357(7)
1.415(10)
2.109(6)
2.316(6)
2.234(6)
1.434(8)
1.426(8)
1.517(8)
1.534(9)
1.374(13)
1.469(14)
1.331(13)
1.436(10)
1.456(11)
1.362(10)
1.202(9)
1.477(8)
1.380(11)
1.400(12)
1.898(10)
1.922(11)
1.935(11)
1.924(12)
1.950(11)
1.885(10)
1.940(11)
1.921(10)
1.936(12)
1.963(12)
1.367(9)
1.375(9)
1.909(8)
1.896(8)
1.950(8)
1.907(9)
1.894(8)
1.947(8)
1.919(8)
1.907(8)
1.916(8)
O-C(15)
Os(1)-C(1)
Os(1)-C(2)
Os(1)-C(3)
Os(2)-C(4)
Os(2)-C(5)
Os(2)-C(6)
Os(3)-C(7)
Os(3)-C(8)
Os(3)-C(9)
Os(3)-C(10)
Os(1)-C(10)
Os(2)-C(10)
1.958(7)
1.940(8)
1.975(7)
1.894(6)
1.912(6)
1.963(7)
1.930(8)
1.905(6)
1.883(8)
2.001(7)
2.519(6)
a
For numbering scheme see Figures 1, 3, and 5.
relative to the diyne fragment, cyclization of 3 is
completely suppressed (vide infra). Instead, the two
main products of the reaction with 3 represent examples
of “regular” µ3-η2 triple-bond coordination to an “Os3-
(CO)10 “ fragment.
(NCHCHCC)CH2Ph))]
and
[HOs3(CO)10(µ-η1:η2-
(Ph(NCHCHCC)CH2Ph)], where the corresponding dis-
tances are 2.282(8) and 2.985(8) Å; 2.225(5) and 3.111(5)
Å, respectively.17 The more pronounced asymmetry in
the latter two clusters may be attributed to steric
interactions between substituents of the coordinated
Syn th esis a n d Ch a r a cter iza tion of [HOs3(CO)10
-
(µ-η1:η2-P h CH2CdCH-CdCH-O)] (5). Reaction be-
tween the triosmium dihydride cluster and ligand 1
affords [HOs3(CO)10(µ-η1:η2-PhCH2CdCH-CdCH-O)]
(5) as the main product along with trace amounts of
unidentified compounds. The molecular structure of 5
was determined by an X-ray diffraction study; an
(29) Mingos, D. M. P. Pure Appl. Chem. 1991, 63, 807.
(30) Gallop, M. A.; J ohnson, B. F. G.; Lewis, J .; Wright, A. H. J .
Chem. Soc., Dalton Trans. 1989, 481.

Reactions of [H2Os3(CO)10]
Organometallics, Vol. 22, No. 17, 2003 3459
pyrrollyl rings and the metal cluster cores. Coordination
of the C(12)dC(13) double bond in 5 to Os(2) results in
its elongation to 1.374(13) Å, which is slightly longer
than the uncoordinated double bond of the furane ring,
which is 1.331(13) Å. The osmium to carbonyl carbon
bond distances in 5 range from 1.885(10) to 1.963(13)
Å, with an average value of 1.927 Å, which matches the
values found for analogous clusters.17,31-33 The coordi-
nation mode of all CO ligands in 5 is very close to linear,
except C(10)O(10), where the Os(3)-C(10)-O(10) angle
is equal to 172.9°. The spectroscopic data for 5 are in
agreement with the solid state structure. The C-O
stretching pattern is very similar to those observed for
related [HOs3(CO)10(µ-η1:η2-alkenyl)] clusters.17,31-33 Am-
bient-temperature 1H, DEPT-135, and 13C{1H} NMR
spectra of the coordinated organic ligand in 5 display
easily assignable signals corresponding to phenyl and
furan rings and the CH2 group, along with the hydride
resonance at -16.1 ppm, typical for a bridging hydride.
The room-temperature 13C{1H} NMR spectrum in the
carbonyl region consists of six resonances of 1/2/1/2/2/2
relative intensities. This spectral pattern matches com-
pletely the fast-exchange limiting spectrum of the
[HOs3(CO)10(µ-η1:η2-PhCdCHPh)] cluster,32 where the
alkenyl bridge oscillates between two osmium atoms,
giving rise to an averaged Cs symmetry for the {Os3-
(CO)10} fragment. In the case of 5 this scrambling
results in confluence of the symmetry-related reso-
nances (C(1)O and C(4)O, C(2)O and C(5)O, C(3)O and
C(6)O, C(7)O and C(9)O) into double intensity signals,
leaving the resonances corresponding to C(8)O and
C(10)O unchanged. This type of dynamic behavior is
common for osmium and ruthenium clusters containing
unsaturated µ-η1:η2-coordinated organic ligands, such
as alkenyl,34 acetylide,35-37 allenylidene,36 or allene.38
F igu r e 2. Schematic representation of the structure of 6.
(µ-η1:η1-(Me-C-(C-C-CH-CH-O))]6 (-15.01 ppm)
and [HOs3(CO)10{µ-η1:η1-(Ph-(NCHCHCC)-C-Me)}]17
(-14.31 ppm). The 13C{1H} NMR spectrum provides
further arguments in favor of the proposed structure;
in this spectrum, as well as in the DEPT-135 spectrum,
the CH carbons of the phenyl rings and the hydrogen-
bonded furan carbon appear as well-resolved resonances
at 129.4 (2C), 127.9 (2C), 127.7 (2C), 123.3 (2C), 129.3
(1C), 127.8 (1C), and 132.6 (1C) ppm. The four signals
of relative intensity 2 in this pattern indicate unhin-
dered rotation of the phenyl rings at room temperature.
The ipso phenyl carbons were found at 136.4 and 161.6
ppm, whereas four low-field signals, 183.1, 181.7, 181.5,
and 177.0 ppm, may be assigned to the other bare
carbons of the coordinated organic ligand. The low-field
shift of these resonances may be attributed to the
coordination of the furan fragment to the clusters and
the presence of the electrophilic oxygen in the hetero-
cyclic system. The 13C spectrum displays 10 signals in
the carbonyl region, indicating that the carbonyl envi-
ronment is completely asymmetric and stereochemically
rigid. Nine of the carbonyl resonances appear in the
regular range for terminal carbonyl ligands (183-200
ppm), whereas the tenth was found at 211.1 ppm. The
latter shift suggests that one carbonyl bridges three
metal atoms. Further evidence for this particular fea-
ture of the carbonyl envelope structure is provided by a
weak 1842 cm-1 band in the IR spectrum of 6.
It was possible to grow single crystals of 6, and an
X-ray analysis confirms the proposed structure of the
cluster, in particular the structure of the coordinated
organic fragment and the bridging CO. Unfortunately,
the poor quality of the crystals precluded the collection
of a high-quality data set, and the disorder of one CO
ligand could therefore not be fully refined. An indirect
confirmation of the proposed structure of 6 is provided
by its reactivity, which is very similar to analogous
clusters with µ-η1:η1-coordination modes of the organic
moiety.17 Upon thermolysis, 6 easily loses a CO ligand
to give the cluster [HOs3(CO)9(µ-η1:η3:η1-Ph(CdCH-Cd
C-O)CPh)] (7), whose crystal and molecular structures
have been determined by X-ray diffraction analysis. The
molecular structure of 7 is shown in Figure 4, and
selected bond lengths and bond distances are listed in
Table 2. The cluster framework in 7 consists of three
metal and three carbon atoms arranged into a pentago-
nal pyramid with three carbons and two osmium atoms
in the basal plane. This structural motif is frequently
observed in products of reactions of iron subgroup
carbonyls with alkynes.39 The spectroscopic and struc-
Syn th esis a n d Ch a r a cter iza tion of [HOs3(CO)10
-
(µ-η1:η1-P h (CdCH-CdC-O)CP h )] (6) a n d Its Th er -
m a l Tr a n sfor m a tion in to [HOs3(CO)9(µ3-η1:η3:η1-
P h (CdCH -CdC-O)CP h )] (7). Reaction of [H2Os3-
(CO)10] with 2, which contains a keto-oxygen in â
position of a substituent, affords the monohydride
cluster [HOs3(CO)10(µ-η1:η1-Ph(CdCH-CdC-O)CPh)]
(6) in nearly quantitative yield. The molecular structure
of 6 (Figure 2) was proposed on the basis of its
spectroscopic (IR, 1H and 13C NMR) and FAB mass
spectrometric data. The 1H NMR spectrum of 6 displays
multiplets derived from the two phenyl rings and the
furan hydrogen (11H) in the typical 7.82-7.02 ppm
range. The hydride signal was observed at -14.86 ppm,
which is close to the values found for [HOs3(CO)10-
(31) Orpen, A. G.; Riera, A. V.; Bryan, E. G.; Pippard, D.; Sheldrick,
G. M.; Rose, K. D. J . Chem. Soc., Chem. Commun. 1978, 723.
(32) Clauss, A. D.; Tachikawa, M.; Shapley, J . R.; Pierpont, C. G.
Inorg. Chem. 1981, 20, 1528.
(33) Sappa, E.; Tiripicchio, A.; Lanfredi, A. M. M. J . Organomet.
Chem. 1983, 249, 391.
(34) Koike, M.; Hamilton, D. H.; Wilson, S. R.; Shapley, J . R.
Organometallics 1996, 15, 4930.
(35) Koridze, A. A.; Zdanovich, V. I.; Lagunova, V. Y.; Sheloumov,
A. M.; Dolgushin, F. M.; Yanovskii, A. I.; Struchkov, Y. T.; Ezer-
nitskaya, M. G.; Vorontsov, E. V.; Petrovskii, P. V. Izv. Akad. Nauk,
Ser. Khim. 1995, 2292.
(36) Krivykh, V. V.; Kizas, O. A.; Vorontsov, E. V.; Dolgushin, F.
M.; Yanovsky, A. I.; Struchkov, Y. T.; Koridze, A. A. J . Organomet.
Chem. 1996, 508, 39.
(37) Su, P.-C.; Chiang, S.-J .; Chang, L.-L.; Chi, Y.; Peng, S.-M.; Lee,
G.-H. Organometallics 1995, 14, 4844.
(38) Aime, S.; Gobetto, R.; Osella, D.; Milone, L.; Rosenberg, E.
Organometallics 1982, 1, 640.

3460 Organometallics, Vol. 22, No. 17, 2003
Tunik et al.
F igu r e 3. ORTEP view of 7.
longer than the Os-C bonds, are incorporated into the
pentagonal pyramidal framework. The 1H and 13C NMR
spectra of 7 fit well to the structure found in the solid
state. The NMR data indicate a fixed orientation of the
ligand both at 325 and at 220 K, which may be expected
since three ligand carbons are incorporated into the
pentagonal “Os3C3” pyramid. However, VT 13C NMR
spectra show that, in contrast to the parent cluster 6,
the carbonyl environment of 7 is not rigid. At least two
independent scrambling pathways, relevant to two
groups of carbonyl ligands, may be discerned in the
temperature range 220-325 K, cf. Figure 4. In the low-
temperature (220 K) spectrum, six resonances of relative
intensity 1 and one resonance of triple intensity can be
observed. The former six resonances account for the
nonequivalent carbonyl ligands coordinated to Os(1) and
Os(2) atoms. This assignment is confirmed by the
presence of typical 2J (Hhydride-C)trans couplings32,34,35,38,40
(11 Hz) for two resonances (C(1)O and C(4)O). The
resonance at 174.8 ppm of triple intensity is assigned
to the three carbonyls of the Os(3) atom, which undergo
a tripodal “turnstile” rotation about the Os center that
is not frozen even at 220 K. This resonance does not
display any broadening on warming up to 325 K,
indicating an absence of carbonyl ligand exchange
between Os(3) and the other osmium atoms. However,
the other six individual CO signals start to broaden on
heating and degrade to the baseline at 325 K. We
propose that this fluxional process is also due to
localized turnstile rotations of the carbonyl ligands
without intermetal exchange. This type of localized
tripodal fluxionality has been observed for several
ruthenium and osmium carbonyl clusters containing
coordinated η2 and η3 organic moieties.34,35,38,41,42 More-
over, a fluxional behavior identical to that described
above for 7 has been verified in the analogous [HRu3-
F igu r e 4. Variable-temperature 13C NMR spectra of 7.
tural characteristics of this compound (cf. Experimental
Section and Table 2) are very similar to the correspond-
ing parameters found for pentagonal pyramidal clusters
formed in analogous thermal reactions.17 The Os-Os
bond lengths in 7 range from 2.7925(4) to 2.9899(4) Å;
the longest bond is located in the basal plane (cf. Figure
3) and is bridged by the hydride ligand. The Os-C bond
lengths in the basal plane of the pentagonal pyramid
are equal to 2.106(8) and 2.068(8) Å, which is very close
to the values found in the analogous clusters [HOs3-
(CO)9{µ3-η1:η3:η1-MeC-CdC-CHdCH-NPh}] (2.106(5)
and 2.078(4) Å) and [HOs3(CO)9{µ3-η1:η3:η1-(OCHd
CHCdC-CMe)}] (2.087(11) and 2.064(11) Å).17 The
three other metal-carbon bonds, which link the apical
Os(3) with the carbon atoms of the basal plane, are
2.329(7), 2.345(7), and 2.357(7) Å, which is substantially
longer (by approximately 0.2 Å) than those in the basal
plane. The relatively large apical metal-carbon bond
lengths may be a result of the strain caused when the
two apical to basal (Os-Os) bonds, which are inherently
(40) Aime, S.; Gambino, O.; Milone, L.; Sappa, E.; Rosenberg, E.
Inorg. Chim. Acta 1975, 15, 53.
(41) Hawkes, G. E.; Lian, L. Y.; Randall, E. W.; Sales, K. D.; Aime,
S. J . Magn. Reson. 1985, 65, 173.
(39) Sappa, E. J . Organomet. Chem. 1999, 573, 139.
(42) Farrugia, L. J .; Rae, S. E. Organometallics 1992, 11, 196.

Reactions of [H2Os3(CO)10]
Organometallics, Vol. 22, No. 17, 2003 3461
the C(11)-C(16)-C(17)-C(18) chain is almost linear:
the C(11)-C(16)-C(17) and C(16)-C(17)-C(18) angles
are equal to 169.1(7)° and 176.7°, respectively.
The carbonyl environment of 9 consists of nine
terminal and one bridging ligand. It is worth noting that
the longest metal to carbon distances, 1.975(7) and
1.963(7) Å, are observed for the C(3)O and C(6)O ligands
disposed in trans positions with respect to the Os-
Calkyne σ-bonds, indicating a substantial trans influence
from these bonds. The terminal ligands are nearly linear
with the Os-C-O angles, falling in the interval 174.3-
(6)-179.4(6)°, the only exception being C(1)O, where the
metal-carbonyl angle is 170.2(6)°. This slight distortion
is probably caused by steric interaction with the C(OH)-
Me2 group of the coordinated diyne. The bridging C(10)O
ligand is coordinated to the Os(1)-Os(2) edge in a highly
asymmetric manner, with the C(10)-Os(1) and C(10)-
Os(2) distances being equal to 2.001(7) and 2.519(6) Å,
respectively. Such asymmetry has also been found in
other [Os3(CO)10(µ3-η2-RC2R′)] clusters, where the cor-
responding distances equal 2.086, 2.302 Å (R ) R′ )
Et)44 and 1.96, 2.6 Å (R ) H, R′ ) C2{Co2(CO)6}SiMe3).45
F igu r e 5. ORTEP view of 9.
(CO)9(µ3,η3-MeCCHCMe)] cluster38,41 by variable-tem-
perature 13C NMR and 13C-13C EXSY studies.
Syn th esis a n d Ch a r a cter iza tion of th e P r od u cts
of th e Rea ction of [H2Os3(CO)10] w ith th e Diyn e 3.
We also examined the reaction of [H2Os3(CO)10] with
the diyne 3. No cyclization of 3 could be observed, which
is in accordance with our proposed general mechanism
for diyne cyclization (vide infra).17 Instead, 3 reacts
The spectroscopic data obtained for 9 indicate that
the molecular structure found in the solid state is
maintained in solution. The room-temperature 1H NMR
spectrum displays two broad resonances at 1.48 and
3.08 ppm, which correspond to the inequivalent Me and
OH groups of the coordinated diyne, respectively. The
as
a “normal” alkyne; thus, the two nonhydride
CO band at 1840 cm-1 in the IR spectrum of 9 indicates
clusters [Os3(CO)10{µ3,η2-Me2(HO)C-CHdCH-CtC-
C(OH)Me2}] (8) and [Os3(CO)10{µ3,η2-Me2(HO)C-CtC-
CtC-C(OH)Me2}] (9) are formed in the reaction of 3
with [H2Os3(CO)10]. Single crystals of 9 suitable for
X-ray analysis were grown, and its crystal structure was
determined in order to verify the identity of 9. The
molecular structure of 9 is shown in Figure 5; it is
closely related to previously determined structures of
[Os3(CO)10(µ3,η2-alkyne)] clusters containing one bridg-
ing CO ligand.43-45 For 9 and related clusters, there is
an idealized Cs symmetry for the alkyne-containing
“Os3C2” fragment, where the vector of the coordinated
triple bond is parallel to the edge of the Os3 triangle,
which is bridged by a CO ligand. However, there are
significant deviations from this idealized structure in
9. In particular, the Os(1)-Os(2)-C(11)-C(12) torsion
angle is equal to -7.8(4)°. Moreover, substantial struc-
tural differences between the alkyne carbons are also
observed. The Os(1)-C(12) and Os(2)-C(11) bond lengths
are different [2.109(6) and 2.164(6) Å, respectively] and
substantially shorter than those that arise from the
π-interaction between the alkyne and Os(3) [Os(3)-
C(11) ) 2.316(6) Å, Os(3)-C(12) ) 2.334(6) Å]. Similar
deviations from the idealized Cs symmetry have been
detected earlier for related clusters.44,45 The C-C bond
distance of the coordinated alkyne moiety in 9 is
substantially elongated [C(11)-C(12) ) 1.434(8) Å],
whereas the C-C distance of the noncoordinated triple
bond is typical for alkynes, 1.202(9) Å. In accord with
the unperturbed nature of noncoordinated triple bond,
ν
the presence of a bridging carbonyl group.
Variable-temperature 13C NMR studies of 9 (Figure
6) showed that the molecule is stereochemically nonrigid
in solution in the temperature range 300-180 K. The
room-temperature 13C NMR spectrum of 9 displays a
broad resonance for the 10 carbonyl ligands at ca. 175
ppm and a set of signals corresponding to the coordi-
nated diyne (165-30 ppm). The assignment of the latter
signals was in part based on the spectroscopic data
obtained for the analogous ruthenium cluster [Ru3-
(CO)10(µ3,η2-HOCH2C2C2CH2OH)]:10 low-field resonances
at 164.4 and 115.2 ppm correspond to C(11) and C(12)
of the coordinated triple bond, while the resonances for
the uncoordinated triple bond occur at 102.9 and 93.4
ppm (C(16) and C(17), respectively). All alkyne reso-
nances are shifted downfield as compared to the reso-
nance for the free ligand 3 (84.4 and 66.2 ppm); the shift
of the resonances for the uncoordinated alkyne moiety
may be attributed to the disappearance of the conju-
gated diyne system. The resonances at 80.1 and 65.6
ppm were assigned to the C(13) and C(18) atoms,
respectively. At room temperature, the methyl substit-
uents in 9 appear as a sharp resonance at 31.4 ppm
superposed on a very broad signal, which is resolved
into two singlets at 31.8 and 31.2 ppm upon cooling to
260 K. The signal at 31.4 ppm is assigned to the methyl
groups bonded to C(18), which are equivalent because
of free rotation around the C(17)-C(18) bond. The broad
resonance observed at room temperature is due to
restricted rotation of the C(13)(OH)Me2 moiety at room
temperature, which is frozen out at 260 K to yield the
two observed singlets. The room-temperature 13C spec-
trum is compatible with exposure of the diyne ligand
to the influence of an averaged “Os3(CO)10“ cluster core,
(43) Deeming, A. J .; Hasso, S.; Underhill, M. J . Chem. Soc., Dalton
Trans. 1975, 1614.
(44) Rosenberg, E.; Bracker-Novak, J .; Gellert, R. W.; Aime, S.;
Gobetto, R.; Osella, D. J . Organomet. Chem. 1989, 365, 163.
(45) Bruce, M. I.; Low, P. J .; Werth, A.; Skelton, B. W.; White, A.
H. J . Chem. Soc., Dalton Trans. 1996, 1551.

3462 Organometallics, Vol. 22, No. 17, 2003
Tunik et al.
F igu r e 6. Variable-temperature 13C NMR spectra of 9, asterisks denote impurities.
where the averaging process is a fast exchange of all
10 carbonyls over the Os3 framework (vide infra).
The further changes in the 13C spectrum that are
observed at lower temperatures may be explained by
the scrambling model proposed44 for the dynamic be-
havior of the closely related [M3(µ-CO)(CO)9(µ3,η2-
RC2R)] clusters (M ) Os,44 Ru46). For example, upon
cooling to 260 K, the broad carbonyl resonance observed
at room temperature splits into three sharp lines of
equal intensity and another relatively broad signal. The
spectroscopic changes that are observed upon cooling
of the sample are in agreement with a rigid structure
F igu r e 7. Schematic representation of the structure of 8.
of the Os(3)(CO)3 moiety and continuous scrambling
inside the Os(1)Os(2)(CO)6(µ2-CO) fragment as proposed
by Aime and co-workers.44,46 In the case of 9, the
dynamics of the carbonyl environment result in simul-
taneous broadening of the signals due to the diyne
ligand. The signals corresponding to the coordinated
triple bond, which are inherently the most sensitive to
the dynamics occurring in the “Os3(CO)10“ unit, disap-
pear into the baseline at temperatures above ca. 260
K, whereas C(13), C(16), C(17), C(18), and the methyl
resonances display lower sensitivity and slower broad-
ening because these atoms are farther away from the
metal-carbonyl cluster core. Unfortunately, a fully
resolved spectrum of 9 could not be obtained, as it was
not possible to freeze out the dynamics of the low-
temperature fluxional process even at 180 K.
tion of the proposed structure of 8 is shown in Figure
7. The mass spectrum of 8 displays a peak for the
molecular ion that matches the proposed formula [Os3-
(CO)10{Me2(HO)C-CHdCH-CtC-C(OH)Me2}] and a
fragmentation pattern corresponding to the loss of seven
CO ligands. The 1H NMR spectrum shows broad signals
for the methyl and OH groups (1.41 and 3.39 ppm,
respectively) along with two doublets of the vinyl
protons at 5.55 and 4.62 ppm. The value of the coupling
constant for the latter resonances, 13 Hz, is typical for
the trans double-bond configuration. No hydride signal
could be detected; this suggests that 8 and 9 are similar
but quite distinct from the other clusters described
above. A group of resonances at typical shifts of terminal
carbonyl ligands could be observed at 172-180 ppm in
the room-temperature 13C{1H} spectrum, and two sig-
nals for CH carbons at 162.0 and 146.0 ppm were
unambiguously assigned from a DEPT-135 spectrum.
Two other low-field resonances (142.6 and 129.5 ppm)
are assigned to the carbons of the coordinated triple
bond. A set of high-field resonances at 80.9 (2 C), 72.8
We have not been able to obtain single crystals of 8
suitable for crystallographic analysis. The proposed
1
structure of 8 is therefore based on mass, IR, and H,
13C NMR spectroscopic studies. A schematic representa-
(46) Aime, S.; Gobetto, R.; Milone, L.; Osella, D.; Violano, L.; Arce,
A. J .; Desanctis, Y. Organometallics 1991, 10, 2854.

Reactions of [H2Os3(CO)10]
Organometallics, Vol. 22, No. 17, 2003 3463
Sch em e 1. P ossible Mech a n ism s of [H2Os3(CO)10] In ter a ction w ith Oxygen -Con ta in in g Con ju ga ted Diyn es
(2 C), and 30.9 (4 C) ppm were assigned as quaternary
carbons of the ligand substituents and Me groups,
respectively, on the basis of a DEPT-135 spectrum. The
shifts are very similar to those observed for the analo-
gous carbons in the spectrum of 9. The data obtained
are in agreement with the structure of 8 that is
schematically shown in Figure 7, in which an en-yne
ligand is coordinated to the Os3(CO)10 fragment through
its triple bond in a µ3-η2 manner. The carbonyl environ-
ment of 8 does not contain bridging ligands, as both the
IR and NMR spectra clearly show. This is in contrast
to the ligand sphere of 9, but is not unusual in the
chemistry of [Os3(CO)10(alkyne)] clusters.47 It is likely
that the enyne ligand found in 8 is formed by reduction
of coordinated diyne triple bonds via transfer of two
hydrides from [H2Os3(CO)10]. The presence of signals
corresponding to the enyne in the mass spectrum of the
reaction mixture (cf. Experimental Section) suggests
that this ligand may dissociate from the cluster.
Discu ssion of th e Rea ction Mech a n ism s. The
reactions described above afforded products whose
structures are in full agreement with previously sug-
gested mechanistic schemes;15,17 the proposed mecha-
nism(s) for cyclization of â-oxygen-containing diynes to
produce five-membered furan type rings in the reaction
with [H2Os3(CO)10] is shown in Scheme 1. The first
reaction pathway shown in Scheme 1 is very similar to
that suggested earlier for the corresponding transfor-
mation of the PhC2C2CH2NHCH2Ph ligand.17 In ligand
1, both of the ortho carbons of the phenyl substituent
and the oxygen atom are in â position relative to the
diyne moiety. Nucleophilic attack by either center can,
in principle, lead to formation of a five-membered ring;
this has, for example, been observed for symmetrically
substituted diynes containing either two alcohol or two
phenyl substituents.6,15 The nature of the formed ring
system and its coordination mode depend on which of
the two triple bonds of the asymmetric diyne that is
initially coordinated to the cluster core and on the
(47) Pierpont, C. G. Inorg. Chem. 1977, 16, 636.

3464 Organometallics, Vol. 22, No. 17, 2003
Tunik et al.
Ta ble 3. Rela tive In ten sities of th e P r oton Sign a ls in th e Clu ster [H2Os3(CO)10(C6H6O2)] Obta in ed in th e
Cou r se of Exp er im en ts: (A) 4 + [H2Os3(CO)10
Deu ter a ted , (B) 4Deu ter a ted + [H2Os3(CO)10], a n d (C) 4 +
[H2Os3(CO)10
]
]
relativea intensities of proton signals in
experiment B
experiment A
H3/H1
experiment C
H3/H1
time, h
H2/H1
0.43
CH3/H1
3.04
3.02
3.01
H2/H1
1.00
H3/H1
0.99
CH3/H1
3.03
H2/H1
1.01
1.01
1.03
CH3/H1
3.02
1
0.45
0.47
0.46
1.03
1.01
0.99
12
24
0.46
0.48
1.01
1.04
1.03
1.01
3.02
3.02
2.98
2.98
average values of 0.46 (0.02) 0.46 (0.01) 3.02 (0.01) 1.02 (0.02) 1.01 (0.02) 3.02 (0.01) 1.02 (0.01) 1.01 (0.02) 2.99 (0.02)
the integrals,
uncertainty in
parentheses
a
With respect to the integral of H1.
relative nucleophilicity of the â-centers. The structure
of 5 indicates that initial coordination of the diyne
occurs through the triple bond adjacent to the alcohol
substituent, followed by nucleophilic attack of the
â-oxygen on a carbon atom of the diyne chain to afford
a µ-η1:η2-alkenyl type coordination of the furan ring.
This is in agreement with the expected higher nucleo-
philicity of the â-oxygen (and the lower pKa of the OH
moiety), as compared to the â-CH group in ligand 1. In
contrast to the rearrangement of the symmetric ligand
HOCH2C2C2CH2OH,6 the closure of the furan ring in
the case of 1 is not accompanied by ligand fragmenta-
tion, most likely because such elimination of a ligand
fragment would involve disruption of the aromatic
phenyl ring. As a result, the furan ring in 5 is coordi-
nated in a µ-η1:η2-alkenyl coordination mode rather than
the µ-η1:η1 bonding mode observed for [HOs3(CO)10{µ-
η1:η1-MeC-CdC-CHdCHO}].6
The proposed reaction sequence for the reaction of [H2-
Os3(CO)10] with ligand 2 is shown in the second reaction
sequence of Scheme 1. Again, the first step of the
reaction consists of the formation of a µ-η1:η2-alkenyl
intermediate through ligand coordination and hydride
transfer. Subsequent nucleophilic attack of the keto-
oxygen onto the coordinated alkenyl fragment results
in closure of the furan ring with the concomitant
formation of a formal Os-carbene fragment involving the
fourth carbon of the erstwhile diyne, resulting in µ-η1:
η1 coordination of the ligand to afford a “diosmacyclo-
pentadien(yl)” ring {Os(1)Os(2)C(11)C(12)C(13)}. The
Os(1)-Os(2) bond may thus be viewed as part of a
conjugated ring system involving the furan moiety; this
type of bonding mode has been observed previously in
the case of [HOs3(CO)10{µ-η1:η1-MeC-CdC-CHdCHO}]6
and [HOs3(CO)10{µ-η1:η1-MeC-CdC-CHdCH-NPh}].17
The high yield (98.6%) of 6, which is the sole identifiable
product of the reaction, indicates that the initial hydride
transfer occurs with high regioselectivity. (The same
degree of regioselectivity cannot be inferred for the
formation of 5 because there are several minor uniden-
tified products formed in that reaction.)
Deu ter iu m La belin g. To get further insight into
possible reaction mechanisms, we studied the reactions
between the deuterated ligand DOCH2C2C2CH2OD (4)
and [H2Os3(CO)10], as well as between 4 and the
1
deuterated cluster [D2Os3(CO)10], using H NMR. The
results are listed in Table 3. Deuteration of the diyne
does not affect the relative intensities of the hydride and
ligand protons in the reaction product, indicating that
the protons (deuterons) of the hydroxyl groups are not
incorporated into the cyclized product, [HOs3(CO)10{µ,η1:
η1-(OCHdCHCdC-CMe)}].6 Further evidence for the
lack of incorporation of the deuterium of the OD groups
into the product cluster was obtained from the mass
spectrum of the product: the isotopic distribution pat-
tern of the molecular ion peak was identical to that of
the product obtained from the reaction with unlabeled
ligand. These observations are in agreement with our
proposal that a molecule of (deuterated) water is
eliminated in the cyclization of the diyne-diol (cf.
Scheme 2). An analogous reaction takes place when
PhNH2CH2C2-C2CH2NH2Ph is reacted with [H2Os3-
(CO)10];17 in this case, a molecule of aniline (which has
been experimentally detected) is eliminated and the
cyclized diyne is coordinated in the same µ-η1:η1 mode
that is observed for [HOs3(CO)10{µ,η1:η1-(OCHdCHCd
C-CMe)}]. On the other hand, the reaction of the
deuterium-enriched cluster with unlabeled ligand showed
that the deuterium label is exclusively incorporated into
the 2-H position of the coordinated ligand, in agreement
with Scheme 2.
The products obtained from the reaction of the diyne
3 with [H2Os3(CO)10] are fundamentally different from
5, 6, and related clusters,6,15,17 but we believe that the
formation of clusters 8 and 9 is nevertheless compatible
with the proposed reaction mechanisms15,17 (vide supra).
It is possible that formation of 8 involves initial hydride
transfer to yield a µ-η1:η2-alkenyl intermediate but that
cyclization of the ligand is prevented by the fact that
the methyl substituents are not liable to undergo 1,3-
shifts (cf. Scheme 1). Possible steric hindrance exerted
by the methyl substituents, which would prevent nu-

Reactions of [H2Os3(CO)10]
Organometallics, Vol. 22, No. 17, 2003 3465
Sch em e 2. Mech a n ism of 2,4-Diyn e-1,6-d iol
Rea r r a n gem en t in th e Rea ction w ith H2Os3(CO)10
ligand 3, the latter species easily reacts with either the
excess of starting ligand to give the nonhydride cluster
9 or with the liberated “en-yne” to give 8. In both
products, the well-known µ3,η2 alkyne coordination
mode is observed.
Con clu sion s
This study has shown the following:
1. Conjugated diynes containing an oxygen atom in â
position of a substituent undergo facile rearrangements
to give furan rings (provided that the other â substit-
uents are mobile, see 3 below).
2. It is likely that the mechanism(s) of the diyne
rearrangements consist of initial formation of a vinyl
intermediate, subsequent nucleophilic attack of the
oxygen onto the third atom of the diyne chain, and (if
necessary/possible) hydrogen shifts along the coordi-
nated organic moiety to give either µ-η1:η2- or µ-η1:η1-
coordinated furan ligands, depending on the nature of
the ligand substituents.
3. It appears that the â methyl groups in ligand 3
prevent cyclization due to their inability to take part in
(1,3-) shifts along the hydrocarbon chain. Instead,
products containing the coordinated diyne, or its par-
tially reduced enyne derivative, are formed.
The results of the studies presented here and pub-
lished earlier6,15,17 indicate that [H2Os3(CO)10] is uniquely
suited as a template for diyne cyclizations, probably due
to the presence of hydrides in its coordination sphere
and its particular electronic and geometrical character-
istics. Along with its ruthenium analogue, [H2Os3(CO)10]
is the only hydride-containing transition metal carbonyl
cluster that is electronically unsaturated and thus a
good electrophile. It should be noted that reaction of
diynes with nonhydride trinuclear ruthenium and os-
mium clusters1,8-10 does not lead to cyclizations. The
same is true for the reaction of diphenyldiacetylene
ligand with another dihydride cluster of the iron sub-
group, [H2Ru4(PPh)(CO)12],4 which results in 1,2- and
1,4-insertion of two hydrides to give coordinated “en-
yne” and diallyl organic fragments; in contrast, the same
ligand is readily cyclized in the reaction with [H2Os3-
(CO)10].15
Ack n ow led gm en t. We gratefully acknowledge fi-
nancial support from INTAS (Grant No 97-3199), the
Russian Foundation for Basic Researches (Grant No 02-
03-32792), the Nordic Council of Ministers (I.A.B.,
V.D.K., M.E.B., T.A.P., and E.N.), the Royal Swedish
Academy of Sciences, the Wenner-Gren Foundation
(S.P.T.), and the Swedish Research Council (VR). We
thank Prof. Carlaxel Andersson for the generous gift of
D2 and Dr. Igor O. Koshevoy for experimental assistance
in the preparation of [D2Os3(CO)10].
cleophilic attack of the oxygen on the diyne moiety,
cannot be excluded. Thus, the second cluster hydride
may be transferred to the alkenyl fragment to produce
an “en-yne” ligand coordinated through its double bond.
The further development of the reaction is completely
in accord with the reactivity patterns found for a large
variety of monoalkynes32,43,44,48 where the transfer of the
second hydride results in dissociation of the alkene
formed to afford coordinatively unsaturated and highly
reactive “Os3(CO)10” species. An indirect confirmation
of such ligand dissociation was provided by the detection
of the free en-yne in the reaction mixture via mass
spectrometry (vide supra). In the reaction involving
Su p p or tin g In for m a tion Ava ila ble: Tables S1-S23,
giving a summary of X-ray analysis, atomic coordinates,
anisotropic thermal parameters, and bond distances and
angles for the structures of 4 clusters. This material is
available free of charge via the Internet at http://pubs.acs.org.
(48) Tachikawa, M.; Shapley, J . R.; Pierpont, C. G. J . Am. Chem.
Soc. 1975, 97, 2.
OM0304107