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Inorganica Chimica Acta 300–302 (2000) 23–31
A comparative study of the isomers of ReOCl
3
(PMe
3
)
2
and
ReOCl
3
(PEt
3
)
2
. The isolation and characterization of ReH
7
(PR
3
)
2
and ReO(OEt)Cl
2
(PR
3
)
2
(R = Me or Et) and the photoelectron
spectrum of ReH
7
(PMe
3
)
2
Kimberly J. Smith
a
, Andrea L. Ondracek
a
, Nadine E. Gruhn
b
,
Dennis L. Lichtenberger
b
, Phillip E. Fanwick
a
, Richard A. Walton
a,
*
a
Department of Chemistry, Purdue Uniersity, 1393 Brown Building, West Lafayette, IN 47907 -1393, USA
b
Department of Chemistry, Uniersity of Arizona, Tucson, AZ 85721, USA
Received 25 May 1999; accepted 20 August 1999
Abstract
The reactions of mer – trans -ReOCl
3
(PPh
3
)
2
with PMe
3
and PEt
3
provide a route to the isomers fac – cis -ReOCl
3
(PR
3
)
2
and
mer – trans -ReOCl
3
(PR
3
)
2
(R =Me or Et) which can be converted to ReH
7
(PR
3
)
2
(R =Me or Et) in ca. 60% yield by reaction with
LiAlH
4
in THF and subsequent hydrolysis of the reaction mixtures. The properties of these heptahydrides have been examined,
including studies of the remarkable stability of aqueous solutions of ReH
7
(PMe
3
)
2
and the measurement of the gas-phase He(I)
photoelectron spectrum of this complex. While the fac – cis and mer – trans isomers of ReOCl
3
(PR
3
)
2
(R =Me or Et) do not
convert to ReO(OEt)Cl
2
(PR
3
)
2
upon reaction with ethanol, these ethoxides can be prepared by the reaction of mer – trans -
ReO(OEt)Cl
2
(PPh
3
)
2
with PMe
3
and PEt
3
. The reactions of the isomers of ReOCl
3
(PMe
3
)
2
with ethylamine, followed by the
treatment of the reaction products with acetone, afford the salt [Me
3
PCMe
2
CH
2
C(O)CH
3
]ReO
4
. The compounds fac – cis -
ReOCl
3
(PEt
3
)
2
, trans -ReO(OEt)Cl
2
(PMe
3
)
2
and [Me
3
PCMe
2
CH
2
C(O)CH
3
]ReO
4
have been structurally characterized by X-ray
crystallography. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Crystal structures; Oxorhenium complexes; Alkoxide complexes; Rhenium polyhydrides; Photoelectron spectroscopy
1. Introduction
Following our recent isolation and full structural
characterization of the fac – cis and mer – trans isomers
of ReOCl
3
(PMe
3
)
2
[1], as well as the corresponding
isomers of the alkylimido complex Re(NEt)Cl
3
(PMe
3
)
2
[2], we have turned our attention to studies of the
reactivities of these and closely related species. This
work was initiated in order to compare the reactivity
patterns of the trialkylphosphine-containing com-
pounds with those of mer – trans -ReOCl
3
(PPh
3
)
2
, one of
the most important synthons in mononuclear rhenium
chemistry [3]. During the course of the present study we
have established convenient synthetic routes to the rhe-
nium heptahydride complexes ReH
7
(PR
3
)
2
(R =Me or
Et), isolated and characterized the ethoxy complexes
mer – trans -ReO(OEt)Cl
2
(PR
3
)
2
(R =Me or Et), and
structurally characterized the fac – cis isomer of
ReOCl
3
(PEt
3
)
2
.
2. Experimental
2.1. Starting materials and reaction procedures
Standard literature procedures were used to prepare
mer – trans -ReOCl
3
(PPh
3
)
2
[4], ReO(OEt)Cl
2
(PPh
3
)
2
[4]
and the fac – cis and mer – trans isomers of
ReOCl
3
(PMe
3
)
2
[1]. For the synthesis of the blue fac –
cis and green mer – trans isomers of ReOCl
3
(PEt
3
)
2
, we
* Corresponding author. Tel.: +1-765-494 5464; fax: +1-765-494
0239.
E-mail address: rawalton@purdue.edu (R.A. Walton)
0020-1693/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII:S0020-1693(99)00419-3