Synthesis and characterization of new transition metal diynyl complexes

Article abstract of DOI:10.1016/S0022-328X(98)01199-1

The reaction of (η⁵-C₅H₅)Mo(CO)(dppe)Cl with LiC≡CC≡CSiMe₃ yielded (η⁵-C₅H ₅)(CO)(dppe)MoC≡CC≡CSiMe₃ (1b) and, as a by-product (η⁵-C₅H₅)Mo(CO)(dppe)Br (1a). Treatment of 1b with 0.2 equivalents of tetrabutylammonium fluoride or (η⁵-C₅H₅)Mo(CO)(dppe)Cl with HC≡CC≡CH gave the terminal butadiyne complex (η⁵-C₅H₅)(CO)(dppe)MoC≡CC≡CH (2). Complex 2 was deprotonated with sec-BuLi or lithium diisopropylamide, and the resulting anion (η⁵-C₅H₅)(CO)(dppe)MoC≡CC≡CLi (3) was trapped with Me₃SiCl to regenerate 1b. The synthesis of Co₂(CO)₄L₂(μ-η²-Me ₃SiC₂C≡CSiMe₃) (L₂ = dppa 4, 2PPh₂Me 5) compounds can be achieved by two methods: from Co₂(CO)₆(μ-dppa) by reaction with Me₃SiC≡CC≡CSiMe₃ in 1:1 ratio to yield 4, or from Co₂(CO)₆(μ-η²-Me₃SiC ₂C≡CSiMe₃) by reaction with dppa (1:1 ratio) and PPh₂Me (1:2 ratio) to yield 4 and 5, respectively. When the Co₂(CO)₄(μ-dppa)(μ-η²-Me ₃SiC₂C≡CSiMe₃) complex was treated with more Co₂(CO)₆(μ-dppa) the green di-substituted complex [Co₂(CO)₄(μ-dppa)]₂(μ-η ²:μ-η²-Me₃SiC₂C ₂SiMe₃) (6) was obtained. Desilylation of 4 with Bu₄NF gave Co₂(CO)₄(μ-dppa)(μ-η²-Me ₃SiC₂C≡CH) (7). All compounds synthesized have been characterized by analytical and spectroscopic data (IR, ¹H-, ³¹P-, ¹³C-NMR, MS). In addition, compounds 1a and 4 were characterized by X-ray structure analysis.

Full text of DOI:10.1016/S0022-328X(98)01199-1

Journal of Organometallic Chemistry 579 (1999) 63–74
Synthesis and characterization of new transition metal diynyl
complexes
Consuelo Moreno a, Jose´ L. Go´mez a, Rosa-Maria Medina a, Mar´ıa-Jose´ Macazaga a,
Avelina Arnanz a, Alan Lough b, David H. Farrar b, Salome´ Delgado a,*
a Departamento de Qu´ımica Inorga´nica, Uni6ersidad Auto´noma de Madrid, E-28049 Madrid, Spain
b Lash Miller Chemical Laboratories, Uni6ersity of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
Received 7 October 1998
Abstract
The reaction of (h5-C5H5)Mo(CO)(dppe)Cl with LiCꢀCCꢀCSiMe3 yielded (h5-C5H5)(CO)(dppe)MoCꢀCCꢀCSiMe3 (1b) and, as
a by-product (h5-C5H5)Mo(CO)(dppe)Br (1a). Treatment of 1b with 0.2 equivalents of tetrabutylammonium fluoride or
(h5-C5H5)Mo(CO)(dppe)Cl with HCꢀCCꢀCH gave the terminal butadiyne complex (h5-C5H5)(CO)(dppe)MoCꢀCCꢀCH (2).
Complex
2
was deprotonated with sec-BuLi or lithium diisopropylamide, and the resulting anion (h5-
C5H5)(CO)(dppe)MoCꢀCCꢀCLi (3) was trapped with Me3SiCl to regenerate 1b. The synthesis of Co2(CO)4L2(m-h2-
Me3SiC2CꢀCSiMe3) (L2=dppa 4, 2PPh2Me 5) compounds can be achieved by two methods: from Co2(CO)6(m-dppa) by reaction
with Me3SiCꢀCCꢀCSiMe3 in 1:1 ratio to yield 4, or from Co2(CO)6(m-h2-Me3SiC2CꢀCSiMe3) by reaction with dppa (1:1 ratio)
and PPh2Me (1:2 ratio) to yield 4 and 5, respectively. When the Co2(CO)4(m-dppa)(m-h2-Me3SiC2CꢀCSiMe3) complex was treated
with more Co2(CO)6(m-dppa) the green di-substituted complex [Co2(CO)4(m-dppa)]2(m-h2:m-h2-Me3SiC2C2SiMe3) (6) was obtained.
Desilylation of 4 with Bu4NF gave Co2(CO)4(m-dppa)(m-h2-Me3SiC2CꢀCH) (7). All compounds synthesized have been character-
ized by analytical and spectroscopic data (IR, H-, 31P-, 13C-NMR, MS). In addition, compounds 1a and 4 were characterized by
1
X-ray structure analysis. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Cyclopentadienyl; Molybdenum; Cobalt; Butadiynyl; Carbonyl complexes
1. Introduction
Linear coordinated carbon chains stabilized by
organometallic building blocks, LnMCxM%L% , are now
n’
Complexes in which sp carbon chains span transi-
tion metal endgroups are attracting increasing atten-
tion [1–4]. These wire-like, unsaturated linear
assemblies offer aesthetic appeal, a variety of interest-
ing fundamental properties, and intriguing possibilities
for molecular-level devices [5]. Specific properties of
transition metal complexes result primarily from the
ability of the metal to participate in p-delocalization,
as well as the potential for interaction of the transi-
tion metal d-orbitals with the conjugated p-orbitals of
the unsaturated carbon chains [6–9].
available for x=1–20 [2b], and a few of them have
been prepared for different oxidation states of the
metal termini, providing ‘consanguineous’ families of
molecules [LnMCxMLn]n+. Two series of these com-
pounds, with rhenium [2d] and iron [3a], were isolated
and fully characterized for three different oxidation
states.
On the other hand, polyynes incorporating metal
clusters have received considerable attention [1] as
possible molecular connectors or bridges as they pro-
mote the formation of linear (molecular-wire) arrays
[10] and their complexes with Co2(CO)6 units are well
known [9].
* Corresponding author. Fax: +34-91-397-4833.
E-mail address: salome.delgado@uam.es (S. Delgado)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01199-1

64
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
In this work, we report the synthesis and character-
2.2. Synthesis of (p5-C5H5)(CO)(dppe)MoCꢀ
CCꢀCSiMe3 (1b)
ization of s- and p-acetylene organometallic com-
plexes of molybdenum and cobalt containing
1,3-diyne units.
A solution of complex (h5-C5H5)Mo(CO)(dppe)Cl
(1.60 g, 2.57 mmol) in THF (50 ml) was treated at
−80°C with a solution of LiCꢀCCꢀCSiMe3 [17], pre-
pared in situ from Me3SiCꢀCCꢀCSiMe3 and MeLi–
LiBr at −80°C in THF (50 ml). The reaction mixture
was gradually warmed to ambient temperature
overnight. The reaction was monitored by FT-IR
spectroscopy until the w(CꢀC) bands of the parent
2. Experimental
2.1. Reagents and general techniques
All manipulations were carried out by using stan-
dard Schlenk vacuum-line and syringe techniques un-
der an atmosphere of oxygen-free Ar. All solvents for
synthetic use were reagent grade. Diethyl ether, hex-
ane and tetrahydrofuran (THF) were dried and dis-
tilled over sodium in the presence of benzophenone
under an Ar atmosphere. Also under Ar, CH2Cl2
(DCM), toluene and CCl4 were dried and distilled
over CaH2, Na and MgSO4, respectively. Methanol
Table 1
Crystal data and structure refinement
Compound
1a
4
Empirical formula
Formula weight
Temperature (K)
Wavelength (A)
Crystal system
Space group
C32H29BrMoOP2 C38H39Co2NO4P2Si2
667.34
150.0(1)
0.71073
Orthorhombic
Pbca
˚
809.68
was stored over molecular sieves (4 A) under Ar. All
173.0(1)
0.71073
Monoclinic
P21/c
solvents were bubbled with Ar for 1 h after distilla-
tion and then stored under Ar, or degassed by means
of at least 3 freeze–pump–thaw cycles after distilla-
tion and before use. Column chromatography was
performed by using Alfa neutral alumina at activity
II. Me3SiCl (Aldrich) was dried and stored over
˚
Unit cell dimensions
˚
a (A)
13.878(3)
17.338(4)
23.456(5)
90
90
90
5644.0(20)
8
1.571
2.018
21.0122(8)
13.4485(5)
30.5942(9)
90
105.590(2)
90
8327.3(5)
8
1.292
˚
b (A)
˚
c (A)
˚
molecular sieves (4 A) and distilled under Ar.
Mo(CO)6, NaH, 1,2-bis(diphenilphosphine)ethane
h (°)
i (°)
(dppe), 1,4-bis(trimethylsilyl)butadiyne (Me3SiCꢀCCꢀ
CSiMe3), pyridine, Fe2(SO4)3(H2O)n, glacial acetic acid
and Cu(OAc)2 (Fluka) and MeLi–LiBr, tetrabutylam-
monium fluoride (FTBA) and PCy3 were used as re-
ceived (Aldrich). n-BuLi and sec-BuLi (Aldrich) were
standardized [11] before use. Me3NO was sublimed
prior to use and stored under Ar. The compounds,
Na[(h5-C5H5)Mo(CO)3] [12], [(h5-C5H5)Mo(CO)3]2
k (°)
3
˚
V (A )
Z
Dcalc. (Mg cm−3
)
Absorption coefficient
(mm−1
F(000)
Crystal size (mm)
Theta range for data
collection (°)
0.968
)
2688
3344
0.35×0.30×0.20 0.10×0.15×0.12
4.10–26.37
4.10–26.42
[13],
(h5-C5H5)Mo(CO)3Cl
[12],
(h5-C5H5)Mo-
Index ranges
05h517,
05k521,
05l529
42 018
5730 [Rint=0.070] 16873 [Rint=0.112]
4610
05h526,
05k516,
−385l536
62 585
(CO)(dppe)Cl [14], Co2(CO)6(m-dppa) [15] and
Co2(CO)6(m-h2-Me3SiC2CꢀCSiMe3) [16] were prepared
according to literature procedures and were purified
by TLC. All reagents were used without further
purification unless otherwise noted. The 1H-NMR
spectra were recorded on a Bruker AMX-300 and 500
instrument. Chemical shifts were measured relative ei-
ther to an internal reference of tetramethylsilane or to
residual protons of the solvents. Infrared spectra were
measured on a Perkin–Elmer 1650 infrared spectrom-
eter. Elemental analyses were performed by the micro-
analytical laboratory of the University Auto´noma of
Madrid on a Perkin–Elmer 240 B microanalyzer.
Electronic spectra were recorded on a Pye Unicam SP
8-100 UV–Vis spectrophotometer. Mass spectra were
measured on a VG-Autospec mass spectrometer for
FAB or AIE by the mass laboratory of the University
Auto´noma of Madrid.
Reflections collected
Independent reflections
Independent reflections
[I\2|(I)]
Absorption correction
Refinement method
9510
Denzo-SMN
Denzo-SMN
Full-matrix least- Full-matrix least-
squares on F2
squares on F2
16873/0/897
0.985
R1=0.0569,
wR2=0.1420
R1=0.1106,
wR2=0.1637
0.00024(12)
Data/restraints/parameters 5730/3/339
Goodness-of-fit on F2
1.063
Final R indices [I\2|(I)] R1=0.0459,
wR2=0.1245
R indices (all data)
R1=0.0604,
wR2=0.1384
0.0001(2)
Extinction coefficient
Largest difference peak
and hole (e A
Position of largest
difference peak
1.267 and −1.448 0.715 and −0.544
−3
˚
)
˚
˚
1.20(1) A from
Br
2.97(1) A from
H(53A)

C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
65
Table 2
Atomic coordinates (×104) and equivalent isotropic displacement
parameters (A ×10 ) for 1a
Table 3
˚
Bond lengths (A) and bond angles (°) for 1a
2
3
˚
˚
Bond lengths (A)
a
x
y
z
Ueq
Mo–C(1)
Mo–C(5)
Mo–C(4)
Mo–C(6)
Mo–C(3)
Mo–C(2)
Mo–P(2)
Mo–P(1)
Mo–Br
1.906(5)
2.277(4)
2.279(4)
2.341(4)
2.360(4)
2.385(4)
2.4371(12)
2.4928(12)
2.6445(8)
1.214(7)
1.404(7)
C(2)–C(6)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
P(1)–C(31)
P(1)–C(21)
P(1)–C(7)
P(2)–C(41)
P(2)–C(8)
P(2)–C(51)
C(7)–C(8)
1.406(7)
1.425(7)
1.417(7)
1.404(7)
1.828(5)
1.832(5)
1.864(5)
1.827(4)
1.830(4)
1.837(5)
1.534(6)
Mo
Br
C(1)
O(1)
Br*2
C(1*2)
O(1*2)
C(2)
4546(1)
2730(1)
4160(3)
3954(4)
4163(10)
3337
1476(1)
1849(1)
1270(3)
1073(3)
883(8)
1739
1897
615(3)
3309(1)
3109(1)
4073(2)
4554(2)
4381(6)
3508
19(1)
38(1)
23(1)
41(1)
88(4)
59
2591
3676
122
4094(3)
4864(4)
5662(4)
5366(4)
4396(4)
4697(1)
5988(1)
5908(3)
6624(3)
4636(3)
3812(4)
3801(4)
4613(4)
5426(4)
5453(4)
3926(3)
3266(3)
2735(4)
2851(4)
3490(4)
4044(3)
6886(3)
7789(3)
8447(3)
8196(4)
7300(4)
6646(3)
5918(3)
6772(4)
6740(5)
5884(5)
5041(5)
5059(4)
2562(2)
2367(2)
2731(2)
3143(2)
3037(2)
3095(1)
3821(1)
3289(2)
3393(2)
2332(2)
2077(2)
1497(2)
1165(2)
1409(2)
1991(2)
3410(2)
3838(2)
4095(2)
3922(2)
3498(2)
3246(2)
3994(2)
3744(2)
3895(2)
4296(2)
4541(2)
4394(2)
4495(2)
4795(2)
5263(2)
5440(2)
5156(2)
4686(2)
32(1)
33(1)
36(1)
35(1)
33(1)
21(1)
22(1)
27(1)
28(1)
24(1)
31(1)
40(1)
44(1)
43(1)
32(1)
24(1)
28(1)
35(1)
37(1)
35(1)
29(1)
25(1)
31(1)
36(1)
34(1)
33(1)
30(1)
28(1)
36(1)
47(1)
47(1)
44(1)
34(1)
C(1)–O(1)
C(2)–C(3)
C(3)
C(4)
C(5)
C(6)
P(1)
P(2)
C(7)
C(8)
1068(3)
910(3)
361(3)
Bond angles (°)
C(1)–Mo–C(5)
C(1)–Mo–C(4)
C(1)–Mo–C(6)
C(1)–Mo–C(3)
C(1)–Mo–C(2)
C(1)–Mo–P(2)
C(1)–Mo–P(1)
P(2)–Mo–P(1)
C(1)–Mo–Br
98.2(2)
132.0(2)
92.9(2)
C(31)–P(1)–C(7)
C(21)–P(1)–C(7)
C(31)–P(1)–Mo
C(21)–P(1)–Mo
C(7)–P(1)–Mo
C(41)–P(2)–C(8)
C(41)–P(2)–C(51)
C(8)–P(2)–C(51)
C(41)–P(2)–Mo
C(8)–P(2)–Mo
C(51)–P(2)–Mo
C(8)–C(7)–P(1)
C(7)–C(8)–P(2)
100.3(2)
101.8(2)
123.71(15)
113.56(14)
111.95(15)
105.6(2)
101.3(2)
98.8(2)
117.94(15)
108.8(2)
121.80(15)
111.0(3)
182(3)
2879(1)
1882(1)
3262(3)
2603(3)
3103(2)
3397(3)
3565(3)
3419(3)
3121(3)
2965(3)
3620(2)
3448(3)
4027(3)
4785(3)
4965(3)
4389(3)
1147(3)
1128(3)
546(3)
−5(3)
15(3)
586(3)
2416(3)
2589(3)
3071(3)
3390(3)
3221(3)
2731(3)
151.3(2)
119.9(2)
79.71(14)
113.33(15)
75.46(4)
86.78(14)
143.07(3)
78.80(3)
173.9(5)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
P(2)–Mo–Br
P(1)–Mo–Br
O(1)–C(1)–Mo
C(31)–P(1)–C(21) 102.7(2)
106.5(3)
1H-NMR (300 MHz, CDCl3): l 7.44 (m, o-H, 8H, Ph);
7.35 (m, m- and p-H, 12H, Ph); 4.51 (d, JHP=2.42 Hz,
Cp); 2.97 (m, 2H, CH2); 1.50 (m, 2H, CH2); 0.15 (s, 9H,
SiMe3). 31P-NMR (CDCl3): l 92.83 (d, JPP=38.61 Hz,
1P); 67.87 (d, JPP=38.67 Hz, 1P). 13C-NMR (CDCl3):
l 141.5 (d, JCP=34 Hz, i-Ph); 137.0 (d, JCP=32 Hz,
CꢀCCꢀCSiMe3); 136.2 (d, JCP=40 Hz, i-Ph); 134.1 (d,
a Ueq is defined as one third of the trace of the orthogonalized Uij
tensor.
compound had disappeared. After 15 h the resulting
solution was evaporated under reduced pressure, and
the residue was purified by TLC using DCM/hexane
(1:2) as eluent. The first red-band, by-product, was
identified as (h5-C5H5)Mo(CO)(dppe)Br (1a) (1.35 g,
75% yield) in comparison with an authentic sample.
The second red-band yielded a reddish–brown solid 1b
(0.14 g, 7% yield). 1a: FT-IR (CH2Cl2, cm−1): w(CO)
1855 (vs). 1H-NMR (300 MHz, CDCl3): l 7.43 (m,
o-H, 8H, Ph); 7.37 (m, m- and p-H, 12H, Ph); 4.45 (d,
J
HP=2.42 Hz, Cp); 2.70 (m, 2H, CH2); 1.70 (m, 2H,
CH2). 31P-NMR (CDCl3): l 92.83 (d, JPP=38.61 Hz,
1P); 67.87 (d, JPP=38.67 Hz, 1P). 1b: FT-IR (CH2Cl2,
cm−1): w(CꢀC) 2185 (w), 2065 (w); w(CO) 1856 (vs).
Fig. 1. ORTEP diagramar of (h5-C5H5)Mo(CO)(dppe)Br, 1a, with 30%
ellipsoids. H atoms on the cyclopentadienyl and phenyl groups have
been removed for clarity.

66
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
Table 4
Table 4 (Continued)
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
˚
parameters (A ×10 ) for 4
x
y
z
Ueq
x
y
z
Ueq
C(2B)
C(3B)
C(4B)
C(5B)
C(6B)
C(7B)
C(8B)
C(9B)
5847(3)
4437(3)
5232(2)
5583(2)
6228(2)
6789(2)
8166(3)
7550(3)
7975(2)
4086(2)
5343(2)
3977(3)
5098(2)
4332(2)
3692(3)
3217(3)
3382(3)
4022(3)
4491(2)
5701(2)
6111(2)
6685(3)
6864(3)
6466(3)
5886(3)
5023(2)
4735(2)
5091(3)
5711(3)
6014(3)
5669(2)
3732(2)
3402(2)
2753(2)
2432(3)
2752(3)
3400(2)
6199(4)
5942(4)
4175(3)
3363(3)
3021(3)
2700(3)
2659(5)
809(4)
2557(4)
4263(4)
4545(4)
3345(4)
2591(3)
2114(3)
2458(4)
2201(4)
1610(4)
1282(4)
1525(4)
2145(3)
1339(4)
1182(4)
1832(4)
2639(4)
2789(4)
396(3)
1485(2)
1565(2)
1439(1)
1356(1)
1453(1)
1539(2)
2182(2)
1680(2)
1175(2)
620(2)
63(2)
64(2)
33(1)
30(1)
32(1)
39(1)
75(2)
72(2)
53(1)
41(1)
41(1)
50(1)
42(1)
39(1)
54(1)
56(1)
47(1)
49(1)
43(1)
39(1)
43(1)
55(1)
58(1)
55(1)
48(1)
35(1)
44(1)
53(1)
51(1)
50(1)
39(1)
37(1)
51(1)
59(2)
67(2)
59(2)
47(1)
Co(1A)
Co(2A)
Si(1A)
Si(2A)
P(1A)
226(1)
407(1)
−242(1)
−2524(1)
286(1)
3645(1)
2846(1)
5234(1)
2236(1)
2271(1)
1337(1)
1262(3)
4814(3)
4837(3)
3537(3)
2385(3)
5010(4)
6021(4)
5817(4)
4036(3)
3198(3)
2854(3)
2580(4)
3112(7)
940(6)
2369(6)
4326(4)
4363(4)
3267(4)
2563(4)
2090(3)
2405(4)
2178(4)
1665(4)
1358(5)
1565(4)
1965(4)
1140(4)
922(5)
4247(1)
3566(1)
3303(1)
3381(1)
4653(1)
3847(1)
4365(1)
4549(1)
4607(1)
3658(2)
2601(1)
2695(2)
3553(2)
3368(2)
3603(1)
3691(1)
3594(1)
3509(2)
2952(2)
3170(3)
3909(2)
4442(2)
4482(2)
3624(2)
2985(2)
5192(1)
5231(2)
5609(2)
5968(2)
5939(2)
5553(2)
4811(1)
4643(2)
4779(2)
5086(2)
5246(2)
5118(2)
3533(1)
3593(2)
3336(2)
3032(2)
2979(2)
3225(2)
3935(2)
3553(2)
3597(2)
4021(2)
4396(2)
4354(2)
800(1)
32(1)
33(1)
37(1)
54(1)
35(1)
33(1)
39(1)
66(1)
60(1)
78(1)
67(1)
68(2)
72(2)
68(2)
33(1)
33(1)
36(1)
44(1)
105(3)
100(3)
89(2)
41(1)
41(1)
50(1)
44(1)
38(1)
53(1)
65(2)
65(2)
69(2)
53(1)
40(1)
51(1)
63(2)
63(2)
61(2)
51(1)
35(1)
49(1)
62(2)
55(1)
50(1)
41(1)
37(1)
58(2)
67(2)
65(2)
57(1)
46(1)
32(1)
32(1)
35(1)
43(1)
33(1)
33(1)
37(1)
62(1)
58(1)
86(2)
65(1)
66(2)
P(2A)
566(1)
425(2)
N(1A)
O(11A)
O(12A)
O(13A)
O(14A)
C(1A)
C(2A)
C(3A)
C(4A)
C(5A)
C(10B)
C(11B)
C(12B)
C(13B)
C(14B)
C(21B)
C(22B)
C(23B)
C(24B)
C(25B)
C(26B)
C(31B)
C(32B)
C(33B)
C(34B)
C(35B)
C(36B)
C(41B)
C(42B)
C(43B)
C(44B)
C(45B)
C(46B)
C(51B)
C(52B)
C(53B)
C(54B)
C(55B)
C(56B)
1439(2)
−677(2)
1755(2)
21(2)
−651(3)
−784(3)
574(3)
−108(2)
−428(2)
−1083(2)
−1650(2)
−3014(3)
−2617(3)
−2784(3)
973(2)
544(2)
1530(2)
2063(2)
−142(1)
−221(2)
−619(2)
−942(2)
−867(2)
−471(2)
270(1)
C(6A)
C(7A)
C(8A)
C(9A)
446(2)
312(2)
9(2)
C(10A)
C(11A)
C(12A)
C(13A)
C(14A)
C(21A)
C(22A)
C(23A)
C(24A)
C(25A)
C(26A)
C(31A)
C(32A)
C(33A)
C(34A)
C(35A)
C(36A)
C(41A)
C(42A)
C(43A)
C(44A)
C(45A)
C(46A)
C(51A)
C(52A)
C(53A)
C(54A)
C(55A)
C(56A)
Co(1B)
Co(2B)
Si(1B)
−155(2)
−31(2)
1521(1)
1523(2)
1793(2)
2054(2)
2052(2)
1786(1)
1041(2)
1385(2)
1286(2)
854(2)
−314(2)
1230(3)
169(2)
−535(4)
−1299(4)
−1146(4)
−222(4)
543(3)
1011(3)
984(4)
644(4)
910(2)
1564(3)
2058(3)
1925(3)
1301(3)
789(3)
−461(2)
−848(3)
−1410(3)
−1591(3)
−1230(3)
−663(3)
74(2)
348(4)
392(4)
725(4)
519(2)
610(2)
1548(5)
2383(5)
2582(4)
320(3)
−660(4)
−1400(4)
−1193(4)
−228(4)
529(4)
849(3)
651(5)
310(5)
158(4)
J
CP=10 Hz, o-Ph); 133.5 (d, JCP=10 Hz, o-Ph); 131–
286(3)
128 (m, m-, p-Ph); 100.2 (s, CꢀCCꢀCSiMe3); 94.3 (s,
Cp); 87.9 (s, CꢀCCꢀCSiMe3); 70.5 (s, CꢀCCꢀCSiMe3);
0.9 (s, SiMe3). Anal. Calc. for C39H38OP2SiMo: C,
65.90; H, 5.39. Found: C, 65.95; H, 5.41.
−97(3)
−685(3)
−903(3)
−530(2)
1409(2)
1635(3)
2263(3)
2690(3)
2478(3)
1841(2)
4890(1)
4765(1)
5282(1)
7628(1)
4925(1)
4588(1)
4833(2)
3583(2)
5653(2)
3484(2)
5335(2)
5609(3)
2.3. Synthesis of (p5-C5H5)(dppe)(CO)MoCꢀCCꢀCH (2)
362(4)
714(4)
2.3.1. Method A
A solution of Bu4NF (1.0 M, 0.42 ml, 0.42 mmol) in
THF was added to a solution of 1b (0.20 g, 0.28 mmol)
in THF (50 ml). The solution was stirred overnight at
room temperature (r.t.). The reaction was monitored by
FT-IR spectroscopy. After removal of the solvent un-
der vacuum, the residue was washed with hexane and
the remaining solid was extracted with diethyl ether.
Solvent was then evaporated from the extract to give
0.11 g of the orange–yellow complex 2 (65% yield).
FT-IR (CH2Cl2, cm−1): w(ꢀCH) 3325 (w); w(CꢀC) 1981
3733(1)
2929(1)
5401(1)
2187(1)
2364(1)
1442(1)
1347(3)
4639(3)
5088(3)
3647(3)
2379(3)
5252(4)
1497(1)
1707(1)
1649(1)
407(1)
1194(1)
710(1)
516(1)
398(1)
1575(2)
2440(1)
2333(2)
Si(2B)
P(1B)
P(2B)
N(1B)
O(11B)
O(12B)
O(13B)
O(14B)
C(1B)
1
(w), 1968 (w); w(CO) 1847 (vs). H-NMR (300 MHz,

C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
67
CDCl3): l 7.43 (m, o-H, 8H, Ph); 7.33 (m, m- and p-H,
12H, Ph); 4.52 (d, JHP=2.28 Hz, Cp); 2.98 (m, 2H,
CH2); 2.34 (s, 1H, CH); 1.42 (m, 2H, CH2). 31P-NMR
(CDCl3) l: 92.80 (d, JPP=38.56 Hz, 1P); 67.80 (d,
J
J
(d, JCP=21 Hz, CꢀCCꢀCH); 136.2 (d, JCP=30 Hz,
i-Ph); 135.9 (d, JCP=40 Hz, i-Ph); 133.8 (d, JCP=20
Hz, o-Ph); 133.6 (d, JCP=10 Hz, o-Ph); 133.3 (d,
(w); w(CO) 2027 (s), 2000 (vs), 1973 (s) 1966 (sh, w);
w(C–C) 1520 (m, coordinated acetylene);. 1H-NMR
(CDCl3): l 7.47 (m, o-H, 8H, Ph); 7.36 (m, m- and
p-H, 12H, Ph); 3.78 (t, 1H, NH); 0.33 (s, 9H, Me3SiC–
); 0.11 (s, 9H, ꢀCSiMe3). 31P-NMR (CDCl3): l 93.45 (s,
2P). 13C-NMR (CDCl3): l 141.4 (d, JCP=21 Hz, i-Ph);
141.2 (d, JCP=21 Hz, i-Ph); 139.7 (d, JCP=23 Hz,
i-Ph); 139.5(d, JCP=24 Hz, i-Ph); 131.5 (d, JCP=7 Hz,
o-Ph); 131.4 (d, JCP=7 Hz, o-Ph); 130.2 (d, JCP=6
PP=38.60 Hz, 1P). 13C-NMR (CDCl3): l 141.4 (d,
CP=39 Hz, i-Ph); 141.1 (d, JCP=35 Hz, i-Ph); 136.7
J
CP=10 Hz, o-Ph); 133.1 (d, JCP=9 Hz, o-Ph); 131–
Hz, p-Ph); 128.8 (d, JCP=5 Hz, p-Ph); 128.7 (d, JCP
5 Hz, p-Ph); 128.6 (d, JCP=5 Hz, p-Ph); 128.5 (d,
CP=5 Hz, p-Ph); 106.8 (s, C(3) Me3SiC4SiMe3); 100.0
=
127 (m, m-, p-Ph); 94.5 (s, CꢀCCꢀCH); 93.9 (s, Cp);
71.9 (s, CꢀCCꢀCH); 59.9 (s, CꢀCCꢀCH). MS (FAB+)
m/z: 639.4 (M+); 611.0 (M+ −CO). Anal. Calc. for
C36H30OP2Mo: C, 67.70; H, 4.74. Found: C, 67.73; H,
4.78.
J
(s, C(4) Me3SiC4SiMe3); 77.5 (s, C(2) Me3SiC4SiMe3);
68.3 (s, C(1) Me3SiC4SiMe3); 1.43(s, Me3SiC–); 0.11 (s,
9H, ꢀCSiMe3). MS (FAB+) m/z: 810.2 (M+); 781.7
(M+ −CO); 753.7 (M+ −2CO); 725.7 (M+ −3CO);
697.7 (M+ −4CO); 625.2 (M+ −4CO-SiMe3); 503.1
2.3.2. Method B
A solution of complex (h5-C5H5)Mo(CO)(dppe)Cl
(1.60 g, 2.57 mmol) in THF (20 ml) and NHEt2 (50 ml)
was treated at −80°C with CuI (75 mg, 0.39 mmol)
and a solution of HCꢀCCꢀCH (ca. 4.0 mmol) in THF
(50 ml), prepared in situ from ClCCꢀCCCl and KOH
at −80°C [17a]. The reaction mixture was gradually
warmed to ambient temperature and a rapid change of
color, from red to orange–yellow, was observed. Upon
removal of the solvent under reduced pressure, an
orange solid was obtained, and the product was ex-
tracted with hexane (25% yield).
(M+ −4CO-(Me3SiCꢀC)2).
Anal.
Calc.
for
C38H39Co2O4P2NSi2: C, 56.37; H, 4.85; N, 1.73; Co,
14.58. Found: C, 56.41; H, 4.85; N, 1.77; Co, 14.67.
2.5.2. Method B
A solution of dppa (0.80 g, 2.08 mmol) in THF (50
ml) was added to a solution of Co2(CO)6(m-h2-
Me3SiC2CꢀCSiMe3) [16] (1.00 g, 2.08 mmol) in the
same solvent. The reaction mixture was stirred at 40°C
overnight. Complex 4 was isolated in 98% yield, in the
same manner used in Section 2.5.1.
2.4. Synthesis of (p5-C5H5)(dppe)(CO)MoCꢀCCꢀCLi
(3)
2.6. Synthesis of Co2(CO)4(PPh2Me)2(v-p2-
Me3SiC2CꢀCSiMe3) (5)
A solution of lithium diisopropylamide, prepared in
situ from n-BuLi and diisopropylamine, was added
dropwise to a solution of 2 (0.10 g, 0.16 mmol) in THF
(20 ml) at −70°C. After 4 h the reaction mixture
turned reddish–brown. FT-IR (THF, cm−1): w(CꢀC)
2200 (w), 2090 (w); w(CO) 1858 (vs).
A solution of PPh2Me (0.60 ml, 3.18 mmol) in
toluene (20 ml) was added to a solution of Co2(CO)6(m-
h2-Me3SiC2CꢀCSiMe3) [16] (0.76 g, 1.58 mmol) in the
same solvent (40 ml). The reaction mixture was stirred
at 90°C for 3 h. Upon filtration and removal of the
solvent under reduced pressure, a red solid was ob-
tained, which was extracted with hexane and purified
by column chromatography on Al2O3 packed in hex-
ane. Hexane/CH2Cl2 (2:1) eluted a red band which
yielded 5 as red crystals (1.14 g, 95% yield). FT-IR
(CH2Cl2, cm−1): w(CꢀC) 2109 (w); w(CO) 2020 (vs),
1982 (sh), 1966 (s) 1945 (sh, w); w(C–C) 1549 (m,
The resulting anion 3 can be trapped by reaction with
Me3SiCl to regenerate 1b in 70% yield.
2.5. Synthesis of Co2(CO)4(v-dppa)(v-p2-
Me3SiC2CꢀCSiMe3) (4)
1
2.5.1. Method A
coordinated acetylene). H-NMR (CDCl3): l 7.57 (m,
A solution of Me3SiCꢀCCꢀCSiMe3 (0.29 g, 1.48
mmol) in THF (80 ml) was added to a suspension of
Co2(CO)6(m-dppa) [15] (1.00 g 1.48 mmol) in the same
solvent (30 ml). The reaction mixture was stirred at
60°C for 18 h and then at r.t. overnight. Upon filtration
and removal of the solvent under reduced pressure, a
red solid was obtained, which was extracted with hex-
ane and purified by column chromatography on Al2O3
packed in hexane. Hexane/CH2Cl2 (1:1) eluted a red
band which yielded 4 as red crystals (1.14 g, 95% yield).
FT-IR (CH2Cl2, cm−1): w(NH) 3329 (m); w(CꢀC) 2112
o-H, 8H, Ph); 7.37 (m, m- and p-H, 12H, Ph); 1.98 (s,
6H, PMe); 0.31 (s, 9H, Me3SiC–); 0.1 (s, 9H,
ꢀCSiMe3). 31P-NMR (CDCl3): l 25.8 (s, 2P).
2.7. Synthesis of [Co2(CO)4(v-dppa)]2(v-p2:v-p2-
Me3SiC2C2SiMe3) (6)
2.7.1. Method A
A solution of Me3SiCꢀCCꢀCSiMe3 (0.29 g, 1.48
mmol) in THF (30 ml) was added to a suspension of
Co2(CO)6(m-dppa) (2.00 g, 2.96 mmol) in the same

68
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
Table 5
˚
Bond lengths (A) and bond angles (°) for 4
˚
Bond lengths (A)
Co(1A)–C(11A)
Co(1A)–C(12A)
Co(1A)–C(5A)
Co(1A)–C(4A)
Co(1A)–P(1A)
Co(1A)–Co(2A)
Co(2A)–C(14A)
Co(2A)–C(13A)
Co(2A)–C(5A)
Co(2A)–C(4A)
Co(2A)–P(2A)
Si(1A)–C(4A)
Si(1A)–C(3A)
Si(1A)–C(1A)
Si(1A)–C(2A)
Si(2A)–C(7A)
Si(2A)–C(10A)
Si(2A)–C(9A)
Si(2A)–C(8A)
P(1A)–N(1A)
P(1A)–C(31A)
P(1A)–C(21A)
P(2A)–N(1A)
P(2A)–C(41A)
P(2A)–C(51A)
O(11A)–C(11A)
O(12A)–C(12A)
O(13A)–C(13A)
O(14A)–C(14A)
C(4A)–C(5A)
C(5A)–C(6A)
C(6A)–C(7A)
1.777(5)
1.782(5)
1.969(4)
1.976(4)
2.2114(13)
2.4620(8)
1.755(5)
1.784(5)
1.951(4)
1.952(4)
2.1927(13)
1.838(5)
1.848(5)
1.852(5)
1.862(5)
1.832(5)
1.848(5)
1.851(7)
1.856(7)
1.686(4)
1.810(4)
1.827(4)
1.691(3)
1.825(5)
1.840(5)
1.150(5)
1.135(5)
1.138(6)
1.157(5)
1.375(6)
1.406(6)
1.207(6)
Co(1B)–C(12B)
Co(1B)–C(11B)
Co(1B)–C(5B)
Co(1B)–C(4B)
Co(1B)–P(1B)
Co(1B)–Co(2B)
Co(2B)–C(14B)
Co(2B)–C(13B)
Co(2B)–C(5B)
Co(2B)–C(4B)
Co(2B)–P(2B)
Si(1B)–C(4B)
Si(1B)–C(2B)
Si(1B)–C(3B)
Si(1B)–C(1B)
Si(2B)–C(8B)
Si(2B)–C(7B)
Si(2B)–C(10B)
Si(2B)–C(9B)
P(1B)–N(1B)
P(1B)–C(31B)
P(1B)–C(21B)
P(2B)–N(1B)
P(2B)–C(41B)
P(2B)–C(51B)
O(11B)–C(11B)
O(12B)–C(12B)
O(13B)–C(13B)
O(14B)–C(14B)
C(4B)–C(5B)
C(5B)–C(6B)
C(6B)–C(7B)
1.763(5)
1.780(5)
1.981(4)
1.982(4)
2.2102(13)
2.4658(8)
1.744(5)
1.777(5)
1.969(4)
1.974(4)
2.1939(13)
1.833(5)
1.858(5)
1.859(5)
1.865(5)
1.831(6)
1.838(5)
1.856(4)
1.865(6)
1.691(4)
1.814(5)
1.834(4)
1.699(3)
1.823(5)
1.828(4)
1.136(5)
1.148(5)
1.154(6)
1.163(5)
1.377(6)
1.387(6)
1.215(6)
Bond angles (°)
C(11A)–Co(1A)–C(12A)
C(11A)–Co(1A)–C(5A)
C(12A)–Co(1A)–C(5A)
C(11A)–Co(1A)–C(4A)
C(12A)–Co(1A)–C(4A)
C(5A)–Co(1A)–C(4A)
C(11A)–Co(1A)–P(1A)
C(12A)–Co(1A)–P(1A)
C(5A)–Co(1A)–P(1A)
C(4A)–Co(1A)–P(1A)
C(11A)–Co(1A)–Co(2A)
C(12A)–Co(1A)–Co(2A)
C(5A)–Co(1A)–Co(2A)
C(4A)–Co(1A)–Co(2A)
P(1A)–Co(1A)–Co(2A)
C(14A)–Co(2A)–C(13A)
C(14A)–Co(2A)–C(5A)
C(13A)–Co(2A)–C(5A)
C(14A)–Co(2A)–C(4A)
C(13A)–Co(2A)–C(4A)
C(5A)–Co(2A)–C(4A)
C(14A)–Co(2A)–P(2A)
C(13A)–Co(2A)–P(2A)
C(5A)–Co(2A)–P(2A)
C(4A)–Co(2A)–P(2A)
C(14A)–Co(2A)–Co(1A)
C(13A)–Co(2A)–Co(1A)
C(5A)–Co(2A)–Co(1A)
C(4A)–Co(2A)–Co(1A)
100.7(2)
C(12B)–Co(1B)–C(11B)
C(12B)–Co(1B)–C(5B)
C(11B)–Co(1B)–C(5B)
C(12B)–Co(1B)–C(4B)
C(11B)–Co(1B)–C(4B)
C(5B)–Co(1B)–C(4B)
C(12B)–Co(1B)–P(1B)
C(11B)–Co(1B)–P(1B)
C(5B)–Co(1B)–P(1B)
C(4B)–Co(1B)–P(1B)
C(12B)–Co(1B)–Co(2B)
C(11B)–Co(1B)–Co(2B)
C(5B)–Co(1B)–Co(2B)
C(4B)–Co(1B)–Co(2B)
P(1B)–Co(1B)–Co(2B)
C(14B)–Co(2B)–C(13B)
C(14B)–Co(2B)–C(5B)
C(13B)–Co(2B)–C(5B)
C(14B)–Co(2B)–C(4B)
C(13B)–Co(2B)–C(4B)
C(5B)–Co(2B)–C(4B)
C(14B)–Co(2B)–P(2B)
C(13B)–Co(2B)–P(2B)
C(5B)–Co(2B)–P(2B)
C(4B)–Co(2B)–P(2B)
C(14B)–Co(2B)–Co(1B)
C(13B)–Co(2B)–Co(1B)
C(5B)–Co(2B)–Co(1B)
C(4B)–Co(2B)–Co(1B)
101.2(2)
142.73(18)
98.20(19)
104.08(18)
99.52(19)
40.80(17)
109.24(15)
99.88(16)
98.68(13)
137.19(13)
100.72(15)
146.98(15)
50.77(12)
50.76(13)
96.41(4)
100.19(19)
141.57(18)
98.95(19)
104.30(18)
40.68(17)
100.01(16)
109.46(15)
97.71(13)
136.85(13)
148.27(15)
97.48(15)
51.16(11)
51.28(12)
97.60(4)
100.0(2)
103.0(2)
143.4(2)
103.0(2)
99.0(2)
98.9(2)
143.2(2)
103.5(2)
105.8(2)
103.4(2)
41.26(17)
99.70(16)
102.32(16)
101.44(13)
139.85(12)
152.24(16)
98.28(18)
51.43(12)
51.61(12)
40.90(17)
99.15(16)
104.87(17)
103.68(13)
140.13(12)
149.84(16)
103.26(18)
51.59(12)
51.60(12)

C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
69
Table 5 (Continued)
P(2A)–Co(2A)–Co(1A)
N(1A)–P(1A)–C(31A)
N(1A)–P(1A)–C(21A)
C(31A)–P(1A)–C(21A)
N(1A)–P(1A)–Co(1A)
C(31A)–P(1A)–Co(1A)
C(21A)–P(1A)–Co(1A)
N(1A)–P(2A)–C(41A)
N(1A)–P(2A)–C(51A)
C(41A)–P(2A)–C(51A)
N(1A)–P(2A)–Co(2A)
C(41A)–P(2A)–Co(2A)
C(51A)–P(2A)–Co(2A)
P(1A)–N(1A)–P(2A)
C(5A)–C(4A)–Si(1A)
C(5A)–C(4A)–Co(2A)
Si(1A)–C(4A)–Co(2A)
C(5A)–C(4A)–Co(1A)
Si(1A)–C(4A)–Co(1A)
Co(2A)–C(4A)–Co(1A)
C(4A)–C(5A)–C(6A)
C(4A)–C(5A)–Co(2A)
C(6A)–C(5A)–Co(2A)
C(4A)–C(5A)–Co(1A)
C(6A)–C(5A)–Co(1A)
Co(2A)–C(5A)–Co(1A)
C(7A)–C(6A)–C(5A)
C(6A)–C(7A)–Si(2A)
O(11A)–C(11A)–Co(1A)
O(12A)–C(12A)–Co(1A)
O(13A)–C(13A)–Co(2A)
O(14A)–C(14A)–Co(2A)
96.60(4)
104.0(2)
100.5(2)
101.1(2)
111.73(13)
114.69(16)
122.54(15)
103.32(19)
104.2(2)
101.3(2)
112.04(14)
118.87(15)
115.28(15)
122.7(2)
143.0(4)
69.3(3)
P(2B)–Co(2B)–Co(1B)
N(1B)–P(1B)–C(31B)
N(1B)–P(1B)–C(21B)
C(31B)–P(1B)–C(21B)
N(1B)–P(1B)–Co(1B)
C(31B)–P(1B)–Co(1B)
C(21B)–P(1B)–Co(1B)
N(1B)–P(2B)–C(41B)
N(1B)–P(2B)–C(51B)
C(41B)–P(2B)–C(51B)
N(1B)–P(2B)–Co(2B)
C(41B)–P(2B)–Co(2B)
C(51B)–P(2B)–Co(2B)
P(1B)–N(1B)–P(2B)
C(5B)–C(4B)–Si(1B)
C(5B)–C(4B)–Co(2B)
Si(1B)–C(4B)–Co(2B)
C(5B)–C(4B)–Co(1B)
Si(1B)–C(4B)–Co(1B)
Co(2B)–C(4B)–Co(1B)
C(4B)–C(5B)–C(6B)
C(4B)–C(5B)–Co(2B)
C(6B)–C(5B)–Co(2B)
C(4B)–C(5B)–Co(1B)
C(6B)–C(5B)–Co(1B)
Co(2B)–C(5B)–Co(1B)
C(7B)–C(6B)–C(5B)
C(6B)–C(7B)–Si(2B)
O(11B)–C(11B)–Co(1B)
O(12B)–C(12B)–Co(1B)
O(13B)–C(13B)–Co(2B)
O(14B)–C(14B)–Co(2B)
94.57(4)
103.73(19)
101.73(19)
101.0(2)
110.50(12)
115.14(15)
122.49(15)
101.33(18)
105.15(19)
102.1(2)
112.35(14)
117.92(15)
116.10(15)
121.5(2)
145.7(3)
69.4(3)
134.7(2)
69.4(2)
134.1(2)
77.63(16)
136.8(4)
69.4(2)
133.9(2)
69.6(2)
132.3(2)
77.12(16)
139.8(4)
69.7(2)
139.4(3)
69.8(2)
135.7(3)
69.7(2)
134.3(3)
77.80(15)
178.6(5)
176.8(5)
175.6(4)
175.9(4)
179.6(5)
178.9(4)
135.9(3)
77.25(15)
178.6(5)
177.8(4)
177.0(4)
176.8(4)
175.9(5)
178.2(4)
solvent (80 ml). The reaction mixture was stirred at 60°C
for 8 h. After removal of the solvent under vacuum the
residue was eluted with hexane/CH2Cl2 (1:1) on an
alumina column. The green band yielded crystals of 6
(1.49 g, 98% yield). FT-IR (CH2Cl2, cm−1): w(NH) 3329
(w); w(CO) 2027 (s), 2000 (vs) 1972 (vs); w(C–C) 1523 (m,
in THF/MeOH (1:5) (80 ml). The solution was refluxed
at 70°C for a period of 8 h. The reaction was stopped
when all the starting material had been consumed (FT-
IR spectroscopy). Upon filtration and removal of the
solvent under reduced pressure, a red solid was obtained
which was washed with hexane, extracted with DCM and
purified by column chromatography on Al2O3 packed in
hexane and using hexane/DCM (1:1) as eluent. Solvent
was evaporated to give 0.60 g of the red complex 7 (95%
yield). FT-IR (CDCl3, cm−1): w(CꢀC) 2070 (w); w(CO)
2036 (s), 1995 (s), 1970 (s); w(C–C) 1523 (m, coordinated
1
coordinated acetylene). H-NMR (CDCl3): l 7.49 (m,
o-H, 16H, Ph); 7.37 (m, m- and p-H, 24H, Ph); 3.84 (t,
2H, NH); 0.40 (s, 18H, Me3SiC–). 31P-NMR (CDCl3):
l 89.83 (s, 4P). MS (FAB+) m/z: 1366.1 (M+ −2CO);
892.1 (M+ −8CO-4Ph); 697.1 (M+ −8CO-4Ph-
(Me3SiCꢀC)2). Anal. Calc. for C66H60Co4O8P4N2Si2: C,
55.62; H, 4.25; N, 1.97; Co, 16.50. Found: C, 55.66; H,
4.26; N, 2.02; Co, 16.58.
1
acetylene). H-NMR (CDCl3): l 7.47 (m, o-H, 8H, Ph);
7.38 (m, m- and p-H, 12H, Ph); 3.74 (t, 1H, NH); 3.20
(s, 1H, ꢀCH); 0.34 (s, 9H, Me3SiC–). 31P-NMR (CDCl3):
l 93.96 (s, 2P). 13C-NMR (CDCl3): l 140.8 (d, JCP=21
Hz, i-Ph); 140.5 (d, JCP=21 Hz, i-Ph); 139.0 (d, JCP=24
Hz, i-Ph); 138.7 (d, JCP=23 Hz, i-Ph); 131.1 (d, JCP=7
Hz, o-Ph); 131.0 (d, JCP=7 Hz, o-Ph); 130.5 (d, JCP=7
Hz, o-Ph); 130.0 (d, JCP=7 Hz, o-Ph); 129.8 (s, p-Ph);
128.4 (d, JCP=5 Hz, m-Ph); 128.3 (d, JCP=5 Hz, m-Ph);
128.0 (d, JCP=5 Hz, m-Ph); 127.9 (d, JCP=5 Hz, m-Ph);
84.8 (s C(3) Me3SiC4H); 82.9 (s, s C(4) Me3SiC4H); 77.1
(s, s C(2) Me3SiC4H); 67.9 (s, s C(1) Me3SiC4H); 0.96 (s,
Me3SiC–). MS (FAB+) m/z: 709.0 (M+ −CO); 625.1
(M+ −4CO); 503.0 (M+ −4CO-Me3SiCꢀCCꢀCH);
2.7.2. Method B
A suspension of Co2(CO)6(m-dppa) (0.20 g, 0.30 mmol)
in THF (30 ml) was added to a solution of 4 (0.24 g, 0.30
mmol) in the same solvent (20 ml). Complex 4 was
isolated in 94% yield, in the same manner used in Section
2.7.1.
2.8. Synthesis of Co2(CO)4(v-dppa)(v-p2-Me3Si-
C2CꢀCH) (7)
A solution of Bu4NF (1.0 M, 0.86 ml, 0.86 mmol) in
THF was added to a solution of 4 (0.69 g, 0.85 mmol)

70
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
combination of 1° phi and omega (with kappa offsets)
scans were used to collect sufficient data. The data
frames were integrated and scaled using the Denzo-
SMN package [18].
The structures were solved and refined using the
SHELXTL¯PC V5.1 package [19]. The position of the Mo
atom, in 1a, was deduced by the Patterson method and
the remaining non-H atoms were located by successive
difference Fourier syntheses. Refinement was by full-
matrix least-squares on F2 using all data (negative
intensities included). The H atom positions were calcu-
lated and the atoms were constrained as riding atoms
with U isotropic 20% larger than the corresponding
C-atoms. As the refinement converged, it became ap-
parent that a minor disorder resulting from interchange
of the Br and CO ligands existed. The atoms Br*1,
C1*2 and O1*2 refined to a site occupancy of 0.12(3)
which were fixed to 0.10 in subsequent cycles of refine-
ment. Distance restraints were applied to Mo–Br*1 and
Mo–C1*2–O1*2 in the final cycles of refinement. Final
positional parameters for 1a are given in Table 2. Views
of the disorder model, anisotropic thermal parameters,
hydrogen atom parameters and structure amplitudes
are available as supplementary material. Table 3 con-
tains selected bond distances and angles for 1a. Fig. 1
presents a molecular diagram of 1a.
The structure of 4 was solved by direct methods and
refinement was by full-matrix least-squares on F2 using
all data (negative intensities included). The H atom
positions were calculated and the atoms were con-
strained as riding atoms with U isotropic 20% larger
than the corresponding C-atoms for the phenyl H
atoms and the N–H atom, and 50% larger for the
methyl H atoms. After examination of difference
Fourier maps it became obvious that there were partial
occupancy disordered solvent molecules in the crystal
lattice. The crystals prepared for the X-ray analysis
were grown from CH2Cl2/hexane mixtures and there-
fore these were the only possible choices. The pattern of
the peaks in the difference Fourier map did not corre-
spond with any ordered orientation of CH2Cl2/hexane
molecules. Accordingly, the contribution of the density
of the disordered solvent molecules was subtracted
from the measured structure factors using the SQUEEZE
[20] option in PLATON [21]. Subsequent refinement con-
verged with a lower R-factor than when attempts were
made to model the disordered solvent. There were no
significant changes to the geometry of the cobalt-con-
taining molecules. Final positional parameters for 4 are
given in Table 4. Anisotropic thermal parameters, hy-
drogen atom parameters and structure amplitudes are
available as supplementary material. Table 5 contains
selected bond distances and angles for 1a. Figs. 2 and 3
presents molecular diagrams of 4 molecules 1 and 2,
respectively.
Fig. 2. ORTEP diagram of Co2(CO)4(dppa)2(m-h2-Me3SiC2CꢀCSiMe3),
4, (molecule 1) with 30% ellipsoids. H atoms have been removed for
clarity.
426.0 (M+ −4CO-Me3SiCꢀCCꢀCH-Ph); 348.9 (M+
4CO-Me3SiCꢀCCꢀCH-2Ph). Anal. Calc.
−
for
C35H31Co2O4P2NSi: C 57.00; H 4.24; N 1.90; Co 15.98.
Found: C 57.05; H 4.26; N 1.92; Co 15.90.
2.9. X-ray crystallography
Dark red, block-shaped crystals of (h5-C5H5)-
Mo(CO)(dppe)Br (1a), are obtained by recrystallization
of the complex from CH2Cl2/hexane mixtures. Red
block-shaped crystals of Co2(CO)4(dppa)2(m-h2-
Me3SiC2CꢀCSiMe3) (4), are obtained by recrystalliza-
tion of the complex from CH2Cl2/hexane mixtures. A
summary of selected crystallographic data for both
complexes is given in Table 1. Data were collected on a
Nonius Kappa CCD diffractometer using graphite
˚
monochromated Mo–Ka radiation (u=0.71073 A). A
Fig. 3. ORTEP diagram of Co2(CO)4(dppa)2(m-h2-Me3SiC2CꢀCSiMe3),
4, (molecule 2) with 30% ellipsoids. H atoms have been removed for
clarity.

C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
71
Scheme 1.
3. Results and discussion
the presence of diethylamine and THF which serves
both to generate the active diynylcopper intermediate
and to remove the HCl as diethylammonium chloride.
3.1. Synthesis and characterization of the butadiynyl
molybdenum complexes (p5-C5H5)(CO)(dppe)MoCꢀ
CCꢀCR (R=SiMe3, H, Li)
Complex
2
can be deprotonated by lithium
diisopropylamide or by sec-BuLi at r.t. to generate the
anion (h5-C5H5)(CO)(dppe)MoCꢀCCꢀCLi (3). This
reaction is another example in which the terminal
proton of a transition metal alkynyl complex is
deprotonated with a base [22]. The resulting anion can
be trapped by reaction with Me3SiCl to regenerate 1 in
70% yield.
Following a known procedure [22], the complex
(h5-C5H5)(CO)(dppe)MoCꢀCCꢀCSiMe3
(1b)
was
obtained from reaction of the corresponding
molybdenum halide (h5-C5H5)Mo(CO)(dppe)Cl [14]
with LiCꢀCCꢀCSiMe3 [17] in THF at r.t. The
butadiynyl compound was isolated after purification by
column chromatography as a reddish–brown powder
in low yield (7%) (Scheme 1). (h5-C5H5)Mo(CO)-
(dppe)Br (1a) has been obtained as a by-product in this
reaction. The spectroscopic and X-ray data support the
identity of this compound.
The novel mononuclear and analytically pure
1
compounds 1b and 2 were characterized by IR, H-,
13C- and 31P-NMR, MS data and by elemental analysis
(see Section 2). The IR spectra of 1b, 2, and 3
complexes in THF display a typical single absorption
band at ca. 1856 cm−1 associated with terminal
Mo–CO stretching (w(CO)) modes. This frequency in
(h5-C5H5)(CO)(dppe)MoCꢀCCꢀCR (R=SiMe3, H, Li)
complexes apparently is weakly sensitive to the
electronic properties of the R group of the acetylide
ligand. Furthermore, these compounds 1b, 2 and 3
exhibit two w(CꢀC) bands. As expected, the w(CꢀC)
values of complex 2 with a proton at the end of the
Removal of the TMS protecting group from 1b was
easily accomplished by treatment with 0.2 equivalents
of Bu4NF in THF at r.t. to give the terminal butadiyne
complex (h5-C5H5)(CO)(dppe)MoCꢀCCꢀH (2), isolated
as an orange–yellow solid in 65% yield. Complex 2 can
also be prepared by CuI-catalyzed direct reaction
between (h5-C5H5)(CO)(dppe)Cl and buta-1,3-diyne in

72
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
butadiynyl ligand are lower than those of the corre-
can be taken as an indication of good communication
between the end groups and the butadiyne system. This
fact has been previously observed in (h5-C5H5)-
(CO)2FeCꢀCCꢀCR complexes [3b].
sponding terminal TMS. The IR spectrum of complex 2
also exhibits a medium w(C–H) band at 3325 cm−1
.
The 1H-NMR data of compounds 1b and 2 (see
Section 2) show a doublet at ca. l 4.56 ppm attributed
to the cyclopentadienyl ligand and two other singlets at
l 0.20 and 1.25 ppm, attributed to the TMS group and
H atom, respectively. The 31P-NMR spectra for these
compounds can be found at ca. l 68 and 94 ppm,
which is consistent with a cis arrangement of the dppe
ligand. The 13C-NMR data exhibit four resonances of
the -C4- chain. All carbon resonances can be unequivo-
cally assigned on the basis of the JCH and JCP coupling
constants (see Section 2). Thus, substitution of TMS
group by a H atom results in variation of the chemical
shifts of the carbon atoms of the chain mainly at Cg
and Cd (87.9, 70.5 and 71.9, 59.9, respectively). This
Crystals of (h5-C5H5)Mo(CO)(dppe)Br (1a), contain
discrete molecules of the complex. As shown in Fig. 1,
the Mo atom has a four-legged piano stool arrange-
ment of an h5-Cp ligand, with Br, CO, and dppe
ligands. The bond length and angles in 1a are compara-
ble to those reported for similar structures [23].
3.2. Synthesis and characterization of butadiynyl cobalt
complexes
It is known that Co2(CO)8 decomposes at ca. 60°C to
give Co4(CO)12 or during prolonged storage at r.t., for
this reason all the reactions were carried out at temper-
Scheme 2.

C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
73
atures lower than 60°C and all products were stored at
−20°C. Reaction of Me3SiCꢀCCꢀCSiMe3 with
Co2(CO)6(m-dppa) in equimolar quantity at 60°C in
THF afforded the expected monosubstituted unsym-
observed in other cobalt–carbonyl bimetallic complexes
possessing a bridging acetylene ligand [25]. The geomet-
ric parameters for 4 have been summarized in Table 5
and Figs. 2 and 3 present views of the two molecules in
the asymmetric unit of the crystal together with the
atom-labeling scheme.
metrical
complex
Co2(CO)6(m-dppa)(m−h2-
Me3SiC2CꢀCSiMe3) (4) as sole product in high yield
(95%). This stable red complex is readily converted to
the green di-substituted complex 6 on treatment with
more Co2(CO)6(m-dppa) or by direct reaction in 1:2
ratio at 60°C. Both reactions are characteristic of termi-
nal acetylenic cobalt complexes (Scheme 2).
The ligands around the Co centers can be considered
to adopt a highly distorted tetrahedral geometry, if the
second Co atom and the two acetylene C atoms are
considered as a ‘cyclopropene-type’ ligand occupying
the fourth coordination site. Thus, the angles subtended
at Co(1A) between the centroid of the Co(2A), C(4A)
and C(5A) ring, and C(11A), C(12A) and P(1A) are
116.3(2), 118.2(2) and 110.9(2)°. The other three angles
subtended at Co(1A) are 100.7(2), 109.2(2) and
99.9(2)°. Similar angles are observed at the other three
Co centers. The Co–Co distances in the two indepen-
No reaction was observed when the Co2(CO)6
(PPh2Me)2 complex was treated with the same alkyne
under thermal conditions, but the analogous
Co2(CO)4(PPh2Me)2)(m−h2-Me3SiC2CꢀCSiMe3)
(5)
can be readily prepared by thermal substitution reac-
tion [16] of two carbonyl ligands on Co2(CO)6(m−h2-
Me3SiC2CꢀCSiMe3) by PPh2Me.
˚
dent molecules 4, 2.4628(8) and 2.4658(8) A, are equiv-
Desilylation of 4 was performed with Bu4NF in
THF/MeOH (1:5) to yield the terminal butadiyne com-
plex 7 as stable deep red crystals.
All these compounds were readily characterized by
the usual methods, details of which are given in Section
2 and 7 has also been characterized by X-ray crystallog-
raphy. The compounds 4, 5, 7 and 8 contain an uncom-
˚
alent. A comparable Co–Co distance of 2.459(2) A is
reported for the related compound Co2(CO)4(PPPh2
(C2Ph))2(m-h2-MeCꢀCMe3) [23].
The C(4)–C(5) distances in the ligand, 1.375(6) and
˚
1.377(6) A, are much longer than the C(6)–C(7) triple
˚
bond values, 1.203(6) and 1.215(6) A, and this reflects
the loss of triple bond character as a result of coordina-
tion of the acetylenic moiety to the Co2 fragment. The
C(4)–C(5) values are longer than 1.302(11) A reported
plexed CꢀC triple bond, which gives
a w(CꢀC)
absorption at 2112 (4), 2109 (5) and 2070 cm−1 (7) (as
expected the w(CꢀC) value of 7 is lower than 4), and a
complexed one, which gives a w(C–C) absorption at ca.
1520 cm−1. In addition, these complexes exhibit three
w(CO) bands at ca. 2060–1970 cm−1 assignable to
terminal stretching modes (w(CO)).
˚
for the unconjugated system Co2(CO)4(PPPh2
(C2Ph))2(m-h2-MeCꢀCMe3) [23]. The C(5)–C(6) dis-
tances, 1.406(6) and 1.387(6), are shorter than normal
C–C singles bonds as a result of conjugation. The
change in hybridization at C(4) and C(5) is also
reflected in the C(4)–C(5)–C(6) angles, 136.8(4) and
139.8(4)°. The C(5)–C(6)–C(7) angles are 178.6(5) and
178.6(5)°.
The 1H-, 31P- and 13C-NMR spectra of 4–7 are
consistent with the proposed structures (Scheme 2). The
13C-NMR resonances of the -C4- chain were easily
observed, and the chemical shifts of the carbon atoms
proved to be sensitive to the nature of the terminal
groups. The carbon resonances of the butadiynyl ligand
can be assigned on the basis of coupling constant,
chemical shifts and in comparison with analogous com-
plexes [24]. As in the molybdenum compounds the
substitution of the TMS group by a H atom results in
variation of chemical shifts at Cg and Cd (see Section
2).
The average P–N distance of the bridging
˚
(Ph2P)2NH ligand, 1.692(5) A, is normal; the P–N
bond lengths are statistically equivalent. The P–N–P
angles are 122.7(2) and 121.5(2)°. These values are
comparable with the average found for bridging
(Ph2P)2NR ligands of 119.3(7)° [2]. All other bond
lengths and angles in 4 are comparable to those re-
ported for similar structures [23].
The electrochemical study of 4, 5 and 6 in different
solvents is currently in progress.
Acknowledgements
3.3. Description of the crystal and molecular structure of
Co2(CO)4(v-dppa)(v-p2-Me3SiC2CꢀCSiMe3) (4)
The authors express their great appreciation to the
Direccio´n General de Ensen˜anza Superior e Investiga-
cio´n Cient´ıfica (Grant No. PB 97/0036), Spain, and to
the Universidad Auto´noma de Madrid for financial
support. Acknowledgments are made (by DHF and
AL) to the Natural Sciences and Engineering Research
Council (NSERC), Canada, for equipment funds.
The single-crystal X-ray structure determination of
Co2(CO)4(dppa)2(m-h2-Me3SiC2CꢀCSiMe3) (4) confi-
rmed the structure presented in Scheme 2. The bimetal-
lic Co complex 4 has two terminal CO ligands on each
Co atom, a bridging 1,3-diyne ligand, Me3SiC4SiMe3,
and bridging dppa ligands. This geometry has been
.

74
C. Moreno et al. / Journal of Organometallic Chemistry 579 (1999) 63–74
Wilkinson, J. Organomet. Chem. 408 (1991) C9. (c) J. Lewis, B.
References
Lin, M.S. Khan, M.R.A. Al-Mandhary, P.R. Raithby, J.
Organomet. Chem. 484 (1994) 161. (d) W.E. Lindsell, P.N.
Preston, P.J. Tomb, J. Organomet. Chem. 439 (1992) 201. (e) P.
Magnus, D.P. Becker, J. Chem. Soc. Chem. Commun. (1985)
640. (f) Y. Rubin, C.B. Knoebler, F. Diederich, J. Am. Chem.
Soc. 112 (1990) 4966. (g) F. Diederich, Nature 369 (1994) 199.
(h) D. Osella, L. Milone, C. Nervi, M. Ravera, Eur. J. Inorg.
Chem. (1998) 1473.
[1] (a) W. Beck, B. Niemer, M. Wieser, Angew. Chem. Int. Ed.
Engl. 32 (1993) 923. (b) H. Lang, Angew. Chem. Int. Ed. Engl.
106 (1996) 569. (c) U. Bunz, Angew. Chem. Int. Ed. Engl. 108
(1996) 1047. (d) A.C. Benniston, V. Grosshenny, A. Harriman,
R. Ziessel, Angew. Chem. Int. Ed. Engl. 34 (1995) 1100.
[2] (a) W. Weng, T. Bartik, M. Brady. B. Bartik, J.A. Ramsden,
A.M. Arif. J.A. Gladysz, J. Amer. Chem. Soc. 117 (1995) 11922.
(b) T. Bartik, B. Bartik, M. Brady, R. Dembinski, J.A. Gladysz,
Angew. Chem. Int. Ed. Engl. 35 (1996) 414. (c) B. Bartik, R.
Dembiski, T. Bartik, A.M. Arif. J.A. Gladysz, New J. Chem. 21
(1997) 739. (d) M. Brady, W. Weng, Y. Zhou, J.W. Seyler, A.J.
Amoroso, A.M. Arif, M. Bo¨hme, G. Frenking, J.A. Gladysz, J.
Amer. Chem. Soc. 119 (1997) 775.
[3] (a) N. Le Narvor, L. Toupet, C. Lapinte, J. Amer. Chem. Soc.
117 (1995) 7129. (b) F. Coat, M.-A Guillevic, L. Toupet, F.
Paul, C. Lapinte, Organometallics 16 (1997) 5988. (c) M.I.
Bruce, L.I. Denisovich, P.J. Low, S.M. Peregudova, N.A.
Ustynyunk, Mendeleev Commun. (1996) 200. (d) M.I. Bruce, M.
Ke, P.J. Low, Chem. Commun. (1996) 2405. (e) B.E. Wood-
worth, P.S. White, J.L. Templeton, J. Am. Chem. Soc. 119
(1997) 828.
[4] (a) W. Weng, J.A. Ramsden, A.M. Arif, J.A. Gladysz, J. Amer.
Chem. Soc. 115 (1993) 3824. (b) W. Weng, T. Bartik, J.A.
Gladysz, Angew. Chem. Int. Ed. Engl. 33 (1994) 2199. (c)
S.B.Falloon, S. Szafert, A.M. Arif, J.A. Gladysz, Chem. Eur. J.
4 (1998) 1033. (d) T. Weyland, C. Lapinte, G. Frapper, M.J.
Calhorda, J-F. Halet, L. Toupet, Organometallics 16 (1997)
2024.
[5] (a) M.D. Ward, Chem. Ind. (1996) 568. (b) M.D. Ward, Chem.
Ind. (1997) 640. (c) D. Astruc, Acc. Chem. Res. 30 (1997) 383.
[6] L.K. Meyers, C. Langhoff, M.E. Thompson, J. Am. Chem. Soc.
114 (1992) 7560.
[10] R.J. Lagow, J.J. Kampa, H.-C. Wei, S.L. Battle, J.W. Genge,
D.A. Laude, C.J. Harper, R. Bau, R.C. Stevens, J.F. Haw, E.
Munson, Science 267 (1995) 362.
[11] W.G. Kofron, L.M. Baclawski, J. Org. Chem. 41 (1976) 1879.
[12] T.S. Piper, G. Wilkinson, Inorg. Chem. 3 (1956) 104.
[13] R. Birdwhistell, P. Hackett, A.R. Manning, J. Organomet.
Chem. 157 (1978) 239.
[14] K. Starker, M.D. Curtis, Inorg. Chem. 24 (1985) 3006.
[15] C. Moreno, M.J. Macazaga, S. Delgado, Inorg. Chim. Acta. 182
(1991) 55.
[16] R.S. Dickson, D.F. Fraser, Adv. Organomet. Chem. 12 (1974)
323.
[17] (a) L. Brandsma, Preparative Acetylenic Chemistry, Elsevier,
New York, 1971. (b) A.B. Holmes, C.L.D. Jennings-White, A.H.
Schulthess, B. Akinde, D.R.M. Walton, J. Chem. Soc. Chem.
Comm. (1979) 840.
[18] Z. Otwinowski, W. Minor, Methods Enzymol. 276 (1997) 307.
[19] G.M. Sheldrick, SHELXTL¯PC V5.1, Bruker Analytical X-ray
Systems, Madison, WI, USA, 1997.
[20] P. Sluis, A.L. Spek. Acta Crystallogr. A46 (1990) 194.
[21] A.L. Spek, PLATON, Molecular Geometry and Graphics Pro-
gram, September 1998 version, University of Utrecht, The
Netherlands.
[22] (a) A. Wong, P.C.W. Kang, C.D. Tagge, D.R. Leon,
Organometallics 9 (1990) 1992. (b) H. Lang, S. Blau, G. Rhein-
wald, L. Zsolnai, J. Organomet. Chem. 494 (1995) 65.
[23] F.H. Allen, O. Kennard, Chem. Des. Automation News 8 (1993)
31.
[24] (a) B. Happ, T. Bartik, C. Zucchi, M.C. Rossi, F. Ghelfi, G.
Pa´lyi, G. Va´radi, G. Szalontai, I.T. Horva´th, A. Chiesi-Villa, C.
Guastini, Organometallics 14 (1995) 809. (b) F. Diederich, Y.
Rubin, O.L. Chapman, N.S. Goroff, Helv. Chim. Acta 77 (1994)
1441.
[7] (a) D.L. Lichtenberger, S.K. Renshaw, R.M. Bullock, J. Am.
Chem. Soc. 115 (1993) 3276. (b) D.L. Lichtenberger, S.K. Ren-
shaw, A. Wong, C.D. Tagge, Organometallics 12 (1993) 3522.
[8] (a) M.I. Bruce, P.J. Low, A. Werth, B.W. Skelton, A.H. White,
J. Chem. Soc. Dalton Trans. 8 (1996) 1551. (b) M.I. Bruce, M.
Ke, P.J. Low, B.W. Skelton, A.H. White, Organometallics 17
(1998) 3539.
[9] (a) F. Diederich, Y. Rubin, Angew. Chem. Int. Ed. Engl. 31
(1992) 1101. (b) B.F.G. Johnson, J. Lewis, P.R. Raithby, D.A.
[25] J.C. Jeffery, R.M.S. Pereira, M.D. Vargas, M.J. Went, J. Chem.
Soc. Dalton Trans. (1995) 1805, and references therein.
.