[Li(dime)2][W(CO)5I] as a novel synthon for the preparation of silyl, amino
and organyl derivatives of pentacarbonyl tungsten (dime = diethylene glycol
dimethyl ether)
W. Palitzsch, U. Bo¨hme* and G. Roewer
Institut fu¨r Anorganische Chemie der TU Bergakademie Freiberg, Leipziger Str. 29, D-09596 Freiberg, Germany
The one-pot reactions of M(CO)6 with dime in the presence
of LiI·Et2O give [Li(dime)2][M(CO)5I] (M = W 1, Mo 2); the
reaction of W(CO)6 with dime in presence of LiI.Et2O leads to
the hitherto unknown [Li(dime)2][W(CO)5I] 1 (Scheme 1).
The X-ray crystal structure analysis of 1 reveals the
molecular structure shown in Fig. 1.‡ The structure was solved
and refined in space group P21/c. The lithium atom is
coordinated by two molecules of dime with a distorted
octahedral coordination geometry. The [W(CO)5I]2 anion has
nearly C4v symmetry with a W–I bond length of 2.871 Å.
First experimental studies showed a surprising stability of 1
during dissolving tests in protic solvents. We could observe
only very slow decomposition in the air. The same synthetic
route was applied to the synthesis of [Li(dime)2][Mo(CO)5I]
2.†
reaction of
1
with LiSiMe2Ph, LiN(SiMe3)2 and
PhCH2MgCl affords the novel complexes [Li(dime)2][W-
(CO)5R] [R = SiMe2Ph 3a, N(SiMe3)2 3b, CH2Ph 3c].
Pentacarbonyl (alkyl- and aryl-alkoxycarbene) group 6 metal
complexes have attracted much interest as useful reagents for
organic synthesis.1,2 The production of water-soluble catalysts
is an area of considerable current interest.3 The role of ionic
metal complexes as active species in homogeneous catalysed
reactions is well documented.4,5 A simple chemical procedure
for the synthesis of anionic monosubstituted derivatives of
transition-metal carbonyls should be highly interesting, espe-
cially to generate coordinatively unsaturated species with
potential applications in catalysis. The design of simple
synthetic routes for these compounds is therefore very im-
portant.
The [W(CO)5I]2 anion represents an interesting building
block. It is very easy to substitute the iodine retaining the d6
character of tungsten. We used the [W(CO)5I]2 anion as a
starting tungsten complex for reactions with different nucleo-
philic reagents to substitute the iodine. For example, complex 1
reacts with LiSiMe2Ph to give compound 3a, and with a lithium
amide (b) to give compound 3b.§ Treatment of 1 with a
Grignard reagent (c) produces complex 3c (Scheme 1).§ All
new compounds were isolated and purified by extraction with
pentane and subsequent recrystallization with dichlorome-
thane.
Compounds containing the [M(CO)5X]2 ion (M = Mo,W;
X = Br) have been synthesized via difficult routes.6 We found a
very simple way to generate such complexes. The one-pot
M(CO)6 + LiI•Et2O
i
ii
Further studies to extend the scope of these reactions to
molybdenum carbonylates and to other nucleophilic reagents, as
well as studies on the reactivity of the obtained products are
under way.
[Li(dime)2][Mo(CO)5I]
[Li(dime)2][W(CO)5I]
2
1
a,b,c
Footnotes
3a
[Li(dime)2][W(CO)5(SiMe2Ph)]
[Li(dime)2][W(CO)5{N(SiMe3)2}]
[Li(dime)2][W(CO)5(CH2Ph)]
b
c
* E-mail: boehme@silicium.aoch.tu-freiberg-de
† All new compounds gave satisfactory analytical data.
‡ Crystal data for [Li(dime)2][W(CO)5I] 1 (yellow crystal from CH2Cl2–
pentane): C17H28ILiO11W, monoclinic, space group P21/c, a = 14,610(3),
b = 13.232(1), c = 14.658(2) Å, b = 113.01(2)°, U = 2608.3(6) Å3, Z = 4,
Dc = 1.849 g cm23, m = 17.927 mm21, F(000) = 1392. A single crystal
of approximate dimensions 0.15 3 0.2 3 0.2 mm was mounted on a glass
fibre under paraffin oil and transfered to the diffractometer. Data were
collected at 283 °C on an Enraf-Nonius CAD-4 diffractometer using
graphite-monochromated Cu-Ka radiation (l = 1.5418 Å) with w–2q
scans. The structure was solved by direct methods and refined by full-matrix
least squares on F2 with anisotropic thermal parameters. Hydrogen atoms
were calculated and allowed to ride on their corresponding carbon atoms.
R = 0.0772 for 4111 reflections (Fo > 2sFo) and 0.0970 for all 5352
reflections, GOF = 1.005. Atomic coordinates, bond lengths and angles,
and thermal parameters have been deposited at the Cambridge Crystallo-
graphic Data Centre (CCDC). See Information for Authors, Issue No. 1.
Any request to the CCDC for this material should quote the full literature
citation and the reference number 182/411.
Scheme 1 Reagents and conditions: i, M = Mo, dime, 80 °C, 2CO, 2Et2O,
70%; ii, M = W, dime, 80 °C, 2CO, 2Et2O, 80%; a, LiSiMe2Ph, dme,
0 °C, 2LiI, 64%; b, LiN(SiMe3)2, THF, 0 °C, 2LiI, 84%; c, CH2PhMgCl,
Et2O, 0 °C, 2MgClI, 77%
C(8)
C(17)
C(7)
O(2)
O(7)
C(9)
I
O(6)
C(6)
C(2)
O(11)
C(10)
C(16)
O(8)
Li
O(5)
C(5)
C(11)
W
C(3)
O(3)
C(12)
C(15)
§ Experimental details and selected spectroscopic data: 1: 1H NMR
(CDCl3, SiMe4) d 3.68, 3.57, 3.37 (dime); 13C NMR (CDCl3, SiMe4) d
O(10)
O(9)
C(1)
O(1)
C(4)
C(14)
202.4, 196.97 (CO), 70.20, 68.99, 59.40 (dime); IR (CDCl3, nCO/cm21
)
O(4)
1
C(13)
1975, 1915, 1850. 2: H NMR (CDCl3, SiMe4) d 3.71, 3.59, 3.41 (dime);
13C NMR (CDCl3, SiMe4) d 219.59, 204.56 (CO); 70.49, 69.25, 59.44
(dime); IR (CDCl3, nCO/cm21) 1982, 1933, 1859. 3a: 1H NMR (CDCl3,
SiMe4) d 7.54 (SiPh); 3.68, 3.59, 3.43 (dime); 0.58 (SiMe2); 29Si NMR
(CH2Cl2-D2O) d 26.13; IR (CHCl3, nCO/cm21) 1925, 1887, 1815. 3b: 1H
NMR (CDCl3) d 3.71, 3.60, 3.40 (dime); 0.00 (SiMe3); 13C NMR (CDCl3)
Fig. 1 Crystal structure of 1. Selected bond distances (Å) and angles (°):
W–I 2.871(2), W–C(1) 1.97(2), W–C(2),C(3),C(4),C(5) 2.04(2)–2.10(2);
I–W–C(1) 178.7(3), I–W–C(2),C(3),C(4),C(5) 86.7(4)–91.2(4); Li–O
2.00(2)–2.22(2).
Chem. Commun., 1997
803
Palitzsch
