223
Journal of Organometallic Chemistry, 413 (1991) 223-232
Elsevier Sequoia S.A., Lausanne
J O M 2 1 6 9 4
A tungstendiiron cluster [NEt4][WFe2{ ~3-~3,
T/5-CH=C=C( tBu)C(O)C2BgHsMe2} (CO) s] derived
from [Fe2(CO) 9] and [NEt 4][W(----Cf-~-'-ft Bu)(CO) 2:
(
T/5-C2B9H9Me2)] *
N i c h o l a s Carr 1, S t e p h e n J. D o s s e t t and F. G o r d o n A. S t o n e 1
Department of Inorganic Chemistry, The Unioersity, Bristol BS8 1TS (UK)
(
Received November 30th, 1990)
Abstract
Treatment of a tetrahydrofuran solution of [NEt4][W(--=--CC:::--CtBu)(CO)2(~/5-C2BgH9Me2)] with
Fe2(CO)9] affords the trimetal complex [NEt4][WFe~{tt3-~!3,~5-CH=C=C(tBu)C(O)C2BgHsMe2}(CO)s],
[
the structure of which has been established by X-ray diffraction. The anion has a core based on an
essentially isosceles triangle of metal atoms [Fe-Fe 2.663(3), W-Fe 2.811(2) and 2.829(2)/k]. Each iron
atom carries three CO groups, whereas the tungsten atom is co-ordinated by two such groups, and by the
open face of a nido-icosahedral C2B9 cage. In the five-membered I~BBCC ring forming the face of the
cage, the boron atom occupying the fl site with respect to the two carbon atoms is o bonded to the
carbon atom of a ketonic group [B-C 1.57(3) A]. The latter in turn is linked to an allenyl fragment
C( tBu~C=CH [C-C average 1.35(2)/k, C - C - C 150(1)°] which spans the face of the WFe2 triangle. The
terminal CH group is attached to the tungsten and to an iron atom [C-W 2.25(1), C-Fe 1.96(1) A], and
the central carbon is linked to the tungsten atom [C-W 2.07 (1) ~k] and also to the second iron atom
[
C-Fe 2.05(1) ,~]. The latter is also bonded to the C(tBu) fragment [C-Fe 2.20(2) ,~] which in turn is
connected to the ketonic group [C(t Bu)-C(O) 1.47(2) A] linking the/x3-C3 moiety to the cage. The NMR
data (1H, 13C-(IH}, and 11B-{1H}) for the new duster compound are reported and discussed.
Introduction
The alkynylmethylidyne c o m p o u n d s [M(-=CC::::---CtBu)(CO)2 L] {M = M o or W, L =
*
/5-C5H5, HB(pz)3 [hydrotris(pyrazol-l-yl)borate], or H B ( d m p z ) 3 [hydrotris(3,5-di-
methylpyrazol-l-yl)borate]} [1] and [NEt4][W(-=CC::--CtBu)(CO)2(,/5-C2B9H9Me2)]
2] are versatile r e a g e n t s for p r e p a r i n g m i x e d - m e t a l complexes. They are particularly
[
interesting precursors s i n c e they c o n t a i n two potentially active sites ( C ~ M or C::-C)
for c o m b i n a t i o n with m e t a l - h g a n d f r a g m e n t s . Species c o n t a i n i n g the l i g a n d s ,/5-C5H5
or 7/5-C2BgH9Me2 generally r e a c t at the C~-M linkages, w h i l e the p r e s e n c e of the
*
i
This paper is dedicated to Professor Peter Pauson on the occasion of his retirement.
Present address: Department of Chemistry, Baylor University, Waco, TX 76798-7348, USA.
0
022-328X/91/$03.50
© 1991 - Elsevier Sequoia S.A.
Carr, Nicholas
