Synthesis, structure and reactivity of bromo- and aquatricarbonylrhenium(I) phosphinite and phosphonite derivatives

Article abstract of DOI:10.1016/S0277-5387(01)00820-8

[ReBr(CO)₅] reacted with phosphinite or phosphonite ligands in benzene or toluene to yield fac-(1) or mer,trans-(2) complexes, ([ReBr(CO)₃(L)₂] L = PPh₂(OMe), a; PPh₂(OEt), b; PPh(OMe)₂, c; PPh(OEt)₂, d) characterized by elemental analysis, mass spectrometry, IR and NMR (¹H, ¹³C and ³¹P) spectroscopies, and for complexes 1b, 2c and 2d, X-ray diffractometry was used. Complexes 2a-2d reacted with Ag[BF₄] in wet acetone to form moderate yield of mer,trans-[Re(H₂O)(CO)₃(L)₂][BF₄] (3). Comparison of the spectra of compounds 3 with those of precursors 2 together with the diffractometric results for compounds 3a-3c, show that all the complexes have the same configuration around the rhenium atom. Crystals of compounds 3 consist of centrosymmetric dimers formed by hydrogen bonds between the water molecules and the BF₄^- anions. The lability of compounds 3 was explored by ¹⁹F and ³¹P NMR, and in the case of 3c the complex [Re(ν¹-BF₄)(CO)₃ {PPh(OMe)₂}₂] (4c) was isolated from the mother liquor. Spectroscopic and diffractometric studies of 4c show monodentate coordination of the tetrafluorborato ligand to the rhenium atom.

Full text of DOI:10.1016/S0277-5387(01)00820-8

Polyhedron 20 (2001) 2371–2383
www.elsevier.com/locate/poly
Synthesis, structure and reactivity of bromo- and
aquatricarbonylrhenium(I) phosphinite and phosphonite derivatives
Rosa Carballo a, Alfonso Castin˜eiras b, Soledad Garc´ıa-Fonta´n a,
Pilar Losada-Gonza´lez a, Ulrich Abram c, Ezequiel M. Va´zquez-Lo´pez a,*
a Departamento de Qu´ımica Inorga´nica, Facultade de Ciencias-Qu´ımica, Uni6ersidade de Vigo, E-36200 Vigo, Galicia, Spain
b Departamento de Qu´ımica Inorga´nica, Facultade de Farmacia, Uni6ersidade de Santiago de Compostela, E-15706 Santiago de Compostela,
Galicia, Spain
c Institut fu¨r Chemie-Radiochemie, Freie Uni6ersita¨t Berlin, D-14195 Berlin, Germany
Received 19 January 2001; accepted 26 April 2001
Abstract
[ReBr(CO)5] reacted with phosphinite or phosphonite ligands in benzene or toluene to yield fac-(1) or mer,trans-(2) complexes,
([ReBr(CO)3(L)2] L=PPh2(OMe), a; PPh2(OEt), b; PPh(OMe)2, c; PPh(OEt)2, d) characterized by elemental analysis, mass
spectrometry, IR and NMR (1H, 13C and 31P) spectroscopies, and for complexes 1b, 2c and 2d, X-ray diffractometry was used.
Complexes 2a–2d reacted with Ag[BF4] in wet acetone to form moderate yield of mer,trans-[Re(H2O)(CO)3(L)2][BF4] (3).
Comparison of the spectra of compounds 3 with those of precursors 2 together with the diffractometric results for compounds
3a–3c, show that all the complexes have the same configuration around the rhenium atom. Crystals of compounds 3 consist of
centrosymmetric dimers formed by hydrogen bonds between the water molecules and the BF−4 anions. The lability of compounds
3 was explored by 19F and 31P NMR, and in the case of 3c the complex [Re(h1-BF4)(CO)3{PPh(OMe)2}2] (4c) was isolated from
the mother liquor. Spectroscopic and diffractometric studies of 4c show monodentate coordination of the tetrafluorborato ligand
to the rhenium atom. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Rhenium(I) complexes; Lewis acid; Group 7 metals; NMR
1. Introduction
Anions neutralizing the resulting products can be
weakly coordinated to metals retaining high Lewis acid
reactivity (this is the case of [Re(h1-BF4)(CO)5]) [2].
When the anion is not coordinated, the system may be
stabilized by agostic interactions between the metal and
ancillary ligands [3] or by the coordination of weak
donor solvents such as diethylether or CH2Cl2 [1b], as
The reactions of 18-electron, coordinatively saturated
complexes generally occur at significantly slower rates
than those of the 16-electron complexes. The 16-elec-
tron carbonyl complexes of the Group 7 metals are
often generated by the abstraction of CH3 from a
methyl precursor [1] or by the protonation of a hydride
to a thermally unstable dihydrogen complex:
described
recently
for
[Re(CO)4−nLn]+[BArF]−
([BArF]−=[B(3,5-(CF3)2(C6H3))4]−). (The coordination
of chlorinated solvents can lead to the evolution of
chloro complexes [1c].)
[MH(L)n]+H+“[M(H2)(L)n]+“[M(L)n]++H2
[MCH3(L)n]+H+“[M(L)n]++CH4
On the other hand, weak basic ‘hard’ donor such as
H2O, MeOH or THF do not bind strongly to most
low-valent transition metals. Owing to this, complexes
including these donors can have interesting reactivities
and catalytic properties [4]. Particularly, the coordina-
tion chemistry of water is attracting increasing atten-
tion [5], aqua or D2O complexes having been used for
the photolytic splitting of water [6], for CꢀH bond
[MCH3(L)n]+Ph3C+“[M(L)n]++Ph3CCH3
* Corresponding author. Tel.: +34-986-812-319; fax: +34-986-
812-382.
E-mail address: ezequiel@uvigo.es (E.M. Va´zquez-Lo´pez).
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(01)00820-8

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R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
deuteration [7], in the water–gas shift reaction [8], and
in organometallic synthesis [5,9]. For instance, the Re%
aqua complex fac-[Re(H2O)(bipy)(CO)3]+, proved to
be an ideal intermediate for the preparation of hydride,
formate and hydrogen carbonate derivatives [9b]:
In our work we obtained both these compounds and
the PPh2(OMe) derivatives 1a and 2a using benzene or
toluene as the solvent. The fac isomers, 1b–1d, were
always obtained after short reaction times but normally
in lower yields than the mer,trans isomers 2b–2d, which
required longer reaction times [12] (Scheme 1).
After the removal of the solvent in vacuo and addi-
tion of MeOH or EtOH, 1a–1d and 2a–2d were iso-
lated as colorless solids that were moderately soluble in
fac-[Re(H2O)(bipy)(CO)3]++E−
“[Re(E)(bipy)(CO)3]+H2O
E−=H−(BH−4 ), HCO2−, HCO−3
toluene
and
highly
soluble
in
chloroform,
Some aqua complexes also have properties with po-
tential applications in inorganic medicine, most of them
likewise arising from the labile nature of the aqua
ligand. For example, cationic aqua-carbonyl complexes
[M(H2O)3(CO)3]+ (M=Re, 99Tc, 99mTc) [10a] have
been proposed as efficient labels for biological
molecules owing to the ready displacement of water
and formation of stable complexes with derivatized
biomolecules. The inclusion of ancillary non-carbonyl
ligands can add to the interest of the resulting complex;
this is the case of the cations fac-[Re(H2O)-
(CO)3(LꢀL)]+ (LꢀL=2,2%-bipyridine or 1,10-phenan-
throline), which have been proposed as agents for lu-
minescent labeling of nucleotides [l0b] and proteins
[l0c].
To further understand the aqua ligand in
organometallic systems, in the work described here we
prepared and characterized four aqua complexes with
phosphorus ligand, namely mer,trans-[Re(H2O)-
(CO)3(L)2][BF4] (L=PPh2(OMe), PPh2(OEt), PPh-
(OMe)2 and PPh(OEt)2). The precursor bromo com-
plexes [ReBr(CO)3(L)2], prepared earlier by Reiman
and Singleton [11] were also fully characterized.
dichloromethane and carbontetrachloride. Their stoi-
chiometry was established by elemental analysis and
mass spectrometry. All the mass spectra contain signals
corresponding to the molecular ions; and fragmentation
seems to be initiated by the loss of either two carbonyls
or the bromo ligand, with intense peaks for ꢀM−2COꢀ
or ꢀM−Brꢀ appearing in most spectra.
The isomers 1 and 2 are differentiated by their vibra-
tional and NMR spectra (Table 1). As reported by
Reiman and Singleton [11] the IR spectra of the fac
complexes show three equally strong w(CO) bands
(2A%+B¦, for Cs local symmetry), while in those of the
mer,trans isomers the band of highest wavenumber is
weak (2A1+B1, C26). The 31P NMR spectra in CDCl3
exhibit a single resonance suggesting the magnetic
equivalence of the two phosphorus ligand, although as
in the hydride complexes [ReH(CO)3(L)2] [13a] the
phosphorus nuclide is slightly more shielded in fac-iso-
mers than in mer,trans-isomers. In the 13C NMR spec-
tra the two isomers are clearly differentiated by the
multiplicities of the signals of the carbonyl groups
coupled to the phosphorus nuclides: the fac and the
mer,trans spectra show a triplet and a double doublet
(sometimes collapsed to a multiplet) and two triplets,
respectively.
2. Results and discussion
2.2. Structure of fac-[ReBr(CO)3{PPh2(OEt)}2] (1b)
2.1. Synthesis of [ReBr(CO)3(L)2] complexes
The structure of 1b was determined by X-ray diffrac-
tometry. The 1b crystals comprise discrete molecules
with no intermolecular distances short enough to sug-
gest bonding. Fig. 1 shows a ZORTEP plot [14] of the
molecular structure, with the numbering scheme used.
Selected bond distances and bond angles are given in
Table 2.
Reiman and Singleton [11] obtained complexes 1b–
1d and 2b–2d by refluxing [ReBr(CO)5] and ligand L in
an equimolar mixture of petroleum ether and benzene.
The rhenium atom is located on a twofold axis
perpendicular to the BrꢀReꢀC(3)ꢀO(3) axis. A 180°
rotation generates two equivalent cis-phosphinite lig-
ands and two carbonyl groups, and results in an orien-
tational disorder [15] confounding the Br and
C(3)ꢀO(3) groups. Similar disorder has been found in
2a and its carbon tetrachloride solvate [16] in this case
owing to the rhenium atom lying in the center of
symmetry.
Within the accuracy allowed by the disorder noted
above, the ReꢀBr and ReꢀC distances are close to those
Scheme 1.

R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
2373
Table 1
Selected IR a and NMR b data for the complexes
Compound
IR
1H NMR
Assignment
3.29m
13C NMR
31P NMR
Assignment
l(CO)
J(13Cꢀ31P)
1a
1b
1c
1d
2031s
1958s
1892s
2031s
1954s
1899s
2039s
1962s
1906s
2033s
1955s
1909s
w(CO)
w(CO)
w(CO)
w(CO)
l(CH3)
187.9t
189.lm
8.4
99.4s
1.03t (J=7.0)
3.49m
l(CH3)
l(CH2)
188.2t
189.2dt
8.6
96.4s
3.51m
l(CH3)
180.0t
187.5m
9.45
10.5
131.7s
125.5s
1.21m
3.75m
3.97m
l(CH3)
l(CH2)
188.3t
189.0m
4.04m
2a
2b
2c
2d
3a
2059w
1964s
1888s
2064m
1955s
1917s
2063w
1957s
1901s
2069w
1973s
1899s
w(CO)
w(CO)
w(CO)
w(CO)
3.55t (J=6.5)
l(CH3)
187.3t
190.6t
7.2
9.8
101.8s
97.2s
1.27t (J=6.9)
3.80m
l(CH3)
l(CH2)
188.2t
191.6dd
7.1
3.64t (J=6.0)
l(CH3)
185.4t
188.5
8.7
11.7
132.1s
126.4s
112.8s
1.36t (J=7.0)
3.94m
4.17m
4.50s,b
3.42t (J=6.0)
l(CH3)
l(CH2)
186.9t
190.0t
9.1
11.1
3418b,m
2069w
1974s
w(OH)
w(CO)
l(H2O)
l(CH3)
190.7t
191.2t
6.5
9.8
1927s
1635b,w
3418b,m
2066w
1977s
l(HOH)
w(OH)
w(CO)
3b
3c
3d
4c
4.30s,b
1.26t (J=7.0)
3.70m
l(H2O)
l(CH3)
l(CH2)
192.8t
194.2t
6.5
10.1
109.1s
140.7s
135.1s
140.5s
1923s
1647b,w
3445b,m
2083w
1975s
l(HOH)
w(OH)
w(CO)
4.74s,b
3.90t (J=5.9)
l(H2O)
l(CH3)
188.8t
190.3t
8.0
11.2
1927s
1631b,w
3418b,m
2072w
1978s
l(HOH)
w(OH)
w(CO)
4.44s,b
1.42t (J=7.0)
4.02m
l(H2O)
l(CH3)
l(CH2)
189.2t
190.7t
7.8
11.1
1924s
4.09m
1651b,w
2073w
1973s
l(HOH)
w(CO)
3.63t (J=5.8)
l(CH3)
189.2t
191.2t
8.4
10.9
1917s
a w in cm−1, b=broad, m=medium, s=strong, w=weak.
b NMR spectra run in CDCl3 except for 4c, for which CD2Cl2 was used. l in ppm, J in Hz; m=multiplet, s=singlet, t=triplet.
found in other bromocarbonylrhenium(I) compounds
The PPh2(OEt) ligand does not seem to suffer any
steric hindrance, the value of 88.81(6)° for the PꢀReꢀPi
angle (i= −x+1, y, −z+3/2) being close to ideal (as
in the bidentate phosphinite complex [ReBr(CO)3(LꢀL)]
,
[17] The fact that the ReꢀP distance, 2.4557(13) A, is
,
slightly longer than the 2.415(2) A [16] in 2a is at-
tributable to the P ligands being trans to the carbonyl
groups in 1b.
(LꢀL=1,2-bis(diphenylphosphinite)ethane)
where

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R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
Fig. 1. Molecular structure of compound 1b showing the numbering scheme (for clarity, just one position of the disordered groups is shown).
PꢀReꢀP=88.92°) [18]. The coordination polyhedron
around the rhenium atom can be accordingly described
as a slightly distorted octahedron. The main distortions
concern C(3)ꢀReꢀP (84.9(4)°), C(2)ꢀReꢀBr (86.75(16)°)
and C(2)ꢀReꢀPi (174.92(15)°).
1 with AgBF4 always yielded oily products from which
we were unable to isolate pure solids (the 31P NMR
spectra of these reaction mixtures showed a complex
group of signals that likely seem to reflect the co-exis-
tence of dinuclear compounds and the phosphine oxide
derivatives OꢁPPh2(OR) and OꢁPPh(OR)2).
After the separation of AgBr, the ionic compounds
mer,trans-[Re(H2O)(CO)3(L)2][BF4] were isolated as
2.3. Structure of mer,trans-[ReBr(CO)3{PPh(OMe)2}2]
(2c) and mer,trans-[ReBr(CO)3{PPh(OEt)2}2] (2d)
Table 2
Fig. 2 is a ZORTEP diagram of the molecular structure
of 2c, with the numbering scheme used. The chief bond
distances and bond angles of 2c and 2d are listed in
Table 2. Like that of 1b, these structures are disordered.
In agreement with the spectroscopic results (see above),
both the compounds are mer,trans isomers. No signifi-
cant intermolecular interactions have been observed.
The ReꢀC and ReꢀBr distances are normal (necessar-
ily so for the former, which were constrained to take
their usual values; see Section 3). The ReꢀP distances
are shorter than in 1b and 2a (Table 2) probably
because of both the trans influence of the CO group in
the fac isomer and the narrower cone angle of the
phosphonite ligand [19].
Main bond distances and bond angles in compounds 1b, 2c and 2d
1b
2c
2d
Bond distances
ReꢀC(3)
ReꢀC(2)
ReꢀP
1.932(15)
1.954(5)
2.4557(13)
2.602(2)
1.884(13)
1.996(4)
a
2.03(1)
2.386(4), 2.389(4) 2.3912(11)
ReꢀBr
2.625(4) a
2.5784(16)
Bond angles
C(2)ꢀReꢀC(3)
C(2)IꢀReꢀC(3)
C(2)ꢀReꢀC(2)i
C(3)ꢀReꢀP
C(2)ꢀReꢀP
C(2)IꢀReꢀP
C(3)ꢀReꢀPi
PꢀReꢀPi
91.8(5)
90.0(5)
88.0(3)
92.5(4)
87.5(4)
180.0
90(1) a
174.4(7) a
84.9(4)
86.5(4)
91.83(16)
174.92(15)
93.3(5)
88.81(6)
178.1(4)
86.75(16)
91.14(16)
93.92(7)
88.18(7)
90.0(3) a
90.13(12)
89.87(12)
93.5(4)
178.63(15)
152.9(3) a
180.0
2.4. Synthesis of mer,trans-[Re(H2O)(CO)3(L)2][BF4],
(3a–3d) and the formation of
C(3)ꢀReꢀBr
C(2)ꢀReꢀBr
C(2)IꢀReꢀBr
PꢀReꢀBr
175.9(4)
89.05(13)
90.95(13)
88.68(3)
91.32(3)
mer,trans-[Re(p1-BF4)(CO)3(PPh(OMe)2}2] (4c)
90.0(3) a
90.42(9) a
89.58(9) a
PiꢀReꢀBr
Compounds 2 reacted with AgBF4 in boiling wet
acetone to form the cationic aqua complexes 3 (Scheme
2). Similar processes are experienced by hydride and
methyl manganese(I) and rhenium(I) complexes
[3,9c,13,20]. By contrast, the reaction of fac compounds
Symmetry codes: 1b, i=−x+1, y, −z+3/2; 2c, 2d, i=−x, −y+1,
−z.
a The listed ReꢀC and CꢀO distances and related values for 2c are
mean values. The standard deviations are estimated by (ꢁ|/n)/n1/2
.

R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
2375
water. This value contrasts with those reported for
[Mn(H2O)(CO)3(LꢀL)][BF4] 2.78 ppm for LꢀL=depe,
2.03 ppm for LꢀL=dppe [9c]. The 13C NMR CO
signals appear around 190 ppm at slightly lower fre-
quencies than for 2, and confirm the persistence of
mer,trans coordination in solution. The 31P NMR spec-
tra consist of single signals owing to the two magneti-
cally equivalent 31P nuclei and lying about 10 ppm
downfield from the 31P NMR signals of 2. The 19F
NMR spectra of freshly prepared solutions in CDCl3
exhibit two sharp singlets at −151.80 and −151.95
ppm with an intensity ratio of approximately 1:4. A
similar pattern in the spectrum of [PdH(H2O)-
(PCy3)2][BF4] [23] is understood to be a B11–B10 iso-
topic shift effect rather than an indication of the pres-
ence of different kinds of fluoride. The spectra of 3
therefore suggest the presence of ‘free’ BF−4 in freshly
prepared solutions of 3 in chloroform.
When the mother liquor of 3c was slowly concen-
trated at room temperature it formed pale-pink single
crystals that were stable in air and moisture, and the
spectral data of which (Table 1) showed no signals for
the coordinated water. An X-ray diffraction study iden-
tified the new compound as mer,trans-[Re(h1-BF4)
(CO)3{PPh(OMe)2}2], 4c (vide infra). The stability of
this compound contrasts with the ready hydrolysis of
[Re(BF4)(CO)5] and the related compounds prepared by
Beck and Su¨nkel [4].
Fig. 2. Molecular structure of compound 2c showing the numbering
scheme (for clarity, just one position of the disordered groups is
shown).
The 31P NMR spectrum of 4c shows a singlet slightly
shifted with respect to the aqua complex 3c. At room
temperature, in the 19F NMR spectrum of the freshly
prepared solutions of 4c, there is a weak, complex
multiplet centered at −149.4 ppm. Although two dif-
ferent signals are expected for the coordinated BF−4 ,
they are observed as separate signals at low tempera-
ture [24].
The formation of 4c from the mother liquor of 3c is
in keeping with the known lability of organometallic
aqua complexes. Likewise, solutions of isolated 3c in
CDCl3 or CD2Cl2 also formed 4c; Fig. 3 shows the 19F
NMR spectrum of a one week-old solution of 3c in
CDCl3 where the formation of 4c is reflected by the
appearance of the characteristic pattern of coordinated
BF−4 (although the free ligand is a more abundant
species). The intensity ratio between the signals of 3c
and 4c remained constant for several weeks and was
not affected by temperature (20–70 °C). 31P and 19F
NMR studies of chloroform solutions of 3a, 3b and 3d
showed similar 4:3 ratios, which implies that the affinity
of [Re(CO)3(L)2]+ for water is not very sensitive to the
identity of the phosphorus ligand.
Scheme 2.
colorless solids that are stable in air and moisture and
soluble in chloroform and alcohols but only very
poorly soluble in diethylether. The resistance of deriva-
tives 3 to moisture contrasts with the reported hygro-
scopic character of [Re(H2O)(CO)5]+Y− (Y−=BF4−
,
AsF6−) [21]
The mass spectra of the isolated aqua complexes
show signals corresponding to the [Re(H2O)(CO)3-
(L)2]+ cation, but the base peak was always that of
[Re(CO)3(L)2]+. The IR spectra show the characteristic
weak–strong–strong pattern of the w(CO) bands of
mer,trans-tricarbonylrhenium(I), although at higher
wavenumbers than in compounds 2 (see Table 1). The
950–1150 cm−1 region is dominated by the (R)CꢀO
bands of the phosphorus ligand, which prevent the
identification of both the IR-active BꢀF absorptions of
‘free’ BF−4 (expected to appear as a strong band in the
1000–1100 cm−1 range and a weak band around 525
cm−1) [23] and the expected weak or medium bands at
1120, 1050 and 980 cm−1 owing to hydrogen bonding
between the anion and the cation via the water
molecule (vide infra) [22].
Horn and Snow [21] have reported that in CH2Cl2
solutions of fac-[Re(H2O)(CO)3(tmen)][BF4] (tmen=te-
tramethylethylidenediammine) the main species is the
tetrafluorborato complex. Surprisingly, the ratio seems
to be inverted for the corresponding phosphonite and
1
The H NMR spectra run in chloroform show the
expected signal around 4.5 ppm owing to coordinated

2376
R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
Fig. 3. 19F NMR spectrum of a CDCl3 solution of 3c after 1 week showing the signals corresponding to free BF4− (*) and coordinated BF4−(2).
phosphinite compounds. The difference may be because
of the electronic differences between tmen and PPh2−
n(OR)n and the differences in the steric demands im-
posed at the ‘vacant’ positions by the different
configurations around the rhenium atom. Specifically,
coordination of BF−4 to the metal should be easier
when the ancillary ligand has a fac,cis arrangement, as
in tmen derivatives, than the mer,trans configuration.
We plan our further investigation towards the effect of
the identity of the counter-ion on the behavior and
reactivity of aqua complexes with other ligands.
angle is 179.2(5)° close to the ideal value. The ReꢀC
and ReꢀP distances are close to those found in 2a [16]
and 2c.
2.5. Structure of mer,trans-[Re(H2O)(CO)3(L)2][BF4]
(L=PPh2(OMe) [3a], PPh2(OEt) [3b] or PPh(OMe)2
[3c])
Figs. 4 and 5 are ZORTEP plots of the mer,trans-
[Re(H2O)(CO)3{PPh2(OMe)}2]+
and
mer,trans-
[Re(H2O)(CO)3{PPh(OMe)2}2]+ cations, showing the
atom-numbering scheme employed. Table 3 lists a selec-
tion of bond distances and bond angles for the three
aqua complexes.
The rhenium atom lies in an octahedral coordination
environment formed by the two mutually trans phos-
phinite or phosphonite ligands, three mer carbonyl
groups and an oxygen atom of the coordinated water.
The main distortion of ideal geometry in the phos-
phinite derivatives concerns the P(2)ꢀReꢀP(1) angle
(174.76(3)° in 3a, 174.33(11)° in 3b). In keeping with the
smaller bulk of the phosphonite ligand [19] in 3c, this
Fig. 4. Molecular structure of mer,trans-[Re(H2O)(CO)3{PPh2-
(OMe)}2]+ cation, showing the numbering scheme.

R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
2377
(CO)3(phen)][CF3SO3]·H2O (phen=1,10-phenanthro-
line) [21b]. The ReꢀO(1W) distances in the phosphinite
compounds are similar to those for the phen derivatives
,
(2.214(6) and 2.210(6) A) and the intermediate between
those found in the pentacarbonyl compound (2.206(8)
,
,
A) and its tmen-substituted derivative (2.239(4) A).
However, the metalꢀO(1W) distance in 3c is the longest
of all, and similar to those found in other complexes
with d6 electronic configuration [9c,25,26] in
[W(H2O)(CO)3(PiPr3)2]·THF [5], e.g. the longest
,
MꢀO(W) distance is 2.320(5) A.
The hydrogen atoms of the water molecule were
successfully located and refined in 3a, and the ReꢀH
,
distances (2.59(5) and 2.61(6) A) and ReꢀO(1W)ꢀH
angles (111(4) and 112(4)°) suggest that the water is
coordinated as usual by the s donation of oxygen lone
pairs [5]. Although we were unable to locate the H2O
hydrogen atoms of 3c, or to refine their locations in 3b,
the ReꢀO(1W) distances and O(1W)ꢀReꢀC/P angles in
this compounds are close to those found in 3a and
together with the spectroscopic similarities to 3a (vide
supra) suggest that in all the three water molecules have
the same coordination mode. This conclusion is rein-
forced by the fact that molecular association is similar
in all the three compounds (vide infra).
Fig. 5. Molecular structure of mer,trans-[Re(H2O)(CO)3-
{PPh(OMe)2}2]+ cation, showing the numbering scheme.
The arrangement of ions in the crystals of com-
pounds of cationic aqua-organometallic complexes [25]
is usually governed by hydrogen bonds. In all
aqua,tmen-rhenium compounds, e.g. the cation and
anion are linked by hydrogen bonds between the aqua
ligand and fluorine atoms. In 3a and 3b both the aqua
ligands of the two cations are linked by OꢀH···F hydro-
gen bonds to the same two anions, thus forming
dimeric structures (Fig. 6). In 3a the parameters of
these bonds are O(1W)ꢀH(1)···F(1)=0.76(5), 1.96(5),
Table 3
Main bond distances and bond angles in 3a, 3b and 3c
3a
3b
3c
Bond distances
ReꢀC(1)
ReꢀC(2)
ReꢀC(3)
ReꢀO(1W)
ReꢀP(1)
2.012(5)
1.978(5)
1.887(5)
2.216(3)
2.4151(11)
2.4132(12)
2.017(8)
2.010(9)
1.873(8)
2.214(6)
2.4084(18)
2.4295(19)
1.917(13)
1.869(16)
1.894(15)
2.263(8)
2.391(3)
2.381(3)
ReꢀP(2)
Bond angles
C(1)ꢀReꢀC(2)
C(1)ꢀReꢀC(3)
C(2)ꢀReꢀC(3)
C(1)ꢀReꢀO(1W)
C(2)ꢀReꢀO(1W)
C(3)ꢀReꢀO(1W)
C(1)ꢀReꢀP(1)
C(2)ꢀReꢀP(1)
C(3)ꢀReꢀP(1)
C(1)ꢀReꢀP(2)
C(2)ꢀReꢀP(2)
C(3)ꢀReꢀP(2)
O(1W)ꢀReꢀP(1)
O(1W)ꢀReꢀP(2)
P(1)ꢀReꢀP(2)
177.70(18)
90.64(19)
88.05(19)
89.19(17)
92.12(17)
179.73(17)
89.67(15)
88.52(14)
93.20(15)
89.63(14)
92.30(14)
92.00(15)
86.60(10)
88.20(10)
174.76(3)
177.4(3)
87.4(4)
90.1(4)
94.5(3)
88.1(3)
178.1(3)
88.8(2)
91.9(2)
90.8(2)
86.1(2)
99.3(2)
92.0(3)
87.79(16)
87.57(16)
174.14(6)
179.2(5)
90.0(6)
89.8(6)
88.6(4)
91.5(5)
177.9(5)
88.6(3)
92.2(4)
92.7(4)
88.0(3)
91.3(4)
88.8(4)
88.9(2)
89.5(2)
176.27(12)
To the best of our knowledge only four other aqua-
carbonylrhenium(I) complexes have been characterized
diffractometrically: [Re(H2O)(CO)5][AsF6], fac-[Re-
(H2O)(CO)3(tmen)][AsF6] and its tetrafluorborate
analog [21a] and the recently reported [Re(H2O)-
Fig. 6. Intermolecular hydrogen bonding in compound 3a.

2378
R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
(CO)2(PPh3)2][BF4]·EtOH [26], [W(H2O)(CO)3(PiPr3)2]-
THF [5] and fac-[Mn(H2O)(CO)3(LꢀL)] [9c] (in the
THF complexes case the chains are formed by
O(THF)···HꢀO hydrogen bonds). However, dimeric
structures like those of 3a and 3b have been observed
before in [Pd(H)(H2O)(PCy3)2][BF]4 [23], [RuCl-
(h3:h2:h2-C12H18)(H2O)][BF4] [27] and [Mo(acac)(h7-
C7H7)(H2O)][BF4] [28]. It is noteworthy that the hydro-
gen bonds in 3a and 3b are slightly longer than in
fac-[Re(H2O)(CO)3(tmen)][BF4] but shorter than in the
AsF−6 derivative, suggesting a significant influence of
steric factors.
However, the water molecule does not establish in-
tramolecular hydrogen bonding with the oxygen atoms
of the corresponding phosphorus ligand. In this case,
the existence of significant interaction can be rejected
by the long distance and unsuitable angles for the
closest contacts (O(1W)ꢀH…(O22)=0.76(5), 2.63(5),
,
3.040(5) A, 116(4)° for 3a; O(1W)ꢀH…(O11)=
,
0.764(10), 2.754(7), 2.996(11) A, 101.0(6)° for
,
3a;O(1W)…O(22)=3.290(10) A for 3c.
Fig. 7. Molecular structure of compound 4c, showing the numbering
scheme.
2.6. Structure of
mer,trans-[Re(p1-BF4)(CO)3{PPh(OMe)2}2] (4c)
Table 4
An X-ray study of the crystals isolated by the slow
evaporation of the mother liquor of 3c showed them to
be [Re(h1-BF4)(CO)3{PPh(OMe)2}2] (4c), in keeping
with the non-observation of signals for the coordinated
water in the IR and NMR spectra. Fig. 7 shows the
molecular structure and the numbering scheme used.
The chief bond distances and bond angles are listed in
Table 4. The rhenium atom is six-coordinated by three
carbonyl atoms, two phenyldimethylphosphonite phos-
phorus atoms and the fluorine atom of the tetrafluorob-
orato ligand.
Main bond distances and bond angles in compound 4c
Bond distances
ReꢀC(1)
ReꢀC(2)
ReꢀP(1)
1.895(15)
1.968(14)
2.388(3)
ReꢀC(3)
ReꢀF(1)
ReꢀP(2)
1.995(13)
2.213(8)
2.390(3)
Bond angles
C(1)ꢀReꢀC(3)
C(2)ꢀReꢀC(3)
C(1)ꢀReꢀC(2)
C(3)ꢀReꢀF(1)
C(1)ꢀReꢀF(1)
C(2)ꢀReꢀF(1)
C(3)ꢀReꢀP(1)
C(2)ꢀReꢀP(1)
89.0(5)
92.9(6)
176.5(5)
177.4(4)
89.5(4)
88.7(5)
89.3(4)
93.1(4)
C(1)ꢀReꢀP(1)
C(3)ꢀReꢀP(2)
C(1)ꢀReꢀP(2)
C(2)ꢀReꢀP(2)
F(1)ꢀReꢀP(1)
F(1)ꢀReꢀP(2)
P(1)ꢀReꢀP(2)
89.8(4)
90.7(4)
89.2(4)
87.9(4)
88.6(2)
91.4(2)
179.02(12)
The coordination geometry around the rhenium
atom is mer,trans, as in the precursor aqua complex, 3c.
The ReꢀP distances are close to those observed in the
corresponding bromo complex (vide supra). The ReꢀF
,
distance (2.213(8) A) is longer than in [Re-
F(CO)(NO)(PPh3)3]+ (1.97(1) A) [29], [Re3H2-
,
i
,
2.652(2) A, 152(5)° and O(1W)ꢀH(2)···F(3) =0.78(6),
1.88(6), 2.649(5) A, 169(6)°; and in 3b, O(1W)ꢀ
H(1)···F(1) =0.648(8), 2.011(10), 2.651(13) A, 170.2(8)°
and O(1W)ꢀH(2)···F(4)=0.763(10), 1.906(13),
2.657(16) A, 167.6° (i=1/2−x, 3/2−y,−z). Although
the H2O hydrogen atoms in 3c cannot be located, short
(CO)9(BF4)]2− (2.138(7) and 2.146(7) A) [30] and
,
,
[ReF(CCH2CtBu)(dppme)2]+ (2.134(4) A) [31], but sim-
,
i
,
ilar to those of compounds with the bridging ligand,
,
such as [ReF(CO)3]4 (2.200(5) A, average) [32] the
mixed valence complex [Re(I)(Fre(V)F5)(CO)5]
,
6
,
(2.20(2)–2.13(3) A) [33] and other d organometallic
O(1W)···F distances suggest the same arrangement
systems with monodentate BF−4 ligands [34].
i
,
(O(1W)ꢀF(2)=2.597(13) A, O(1W)ꢀF(1) =2.634(12)
The replacement of water by the h1-BF4 ligand does
not affect the geometry of the coordination polyhedron
around rhenium significantly. The main deviations from
the ideal octahedral angles are around 2°.
,
A, i= −x, y−1/2, −z+1/2). This contrasts with the
formation of polymeric chains by pentacarbonylrheni-
um(I) and its tmen derivatives or other d6 systems such
as [IrH2(H2O)(THF)(PPh3)2][SbF6] [25], [RuH(H2O)-

R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
2379
3. Experimental
Data for 1c. Yield: 47%; m.p. (dec.), 95 °C (lit. value
94 °C [11]). Anal. Found: C, 33.5; H, 3.1. Calc. for
C19H22BrO7P2Re: C, 33.1; H, 3.2%. FAB MS; m/z (%):
690(29) [M], 662(27) [M−CO], 634(59) [M−2CO],
611(69) [M−Br], 603(21) [M−{2CO,OR}], 583(20)
[M−(Br,CO)].
Data for 1d. Yield: 45%; m.p. (dec.), 95 °C (lit. value
96 °C [11]). Anal. Found: C, 37.2; H, 4.3. Calc. for
C23H30BrO7P2Re: C, 37.0; 4.1%. FAB MS (FAB); m/z
(%): 746(33) [M], 718(45) [M−CO], 690(93) [M−
2CO], 667(100) [M−Br], 639(39) [M−(Br,CO)].
3.1. Materials and instrumentation
All operations were carried out under dry dinitrogen
or argon atmosphere using standard Schlenk tech-
niques. All solvents were dried over appropriate drying
agents, degassed on a vacuum line and distilled in an
Ar atmosphere [35].
Re2(CO)10 (ABCR), AgBF4 (Fluka), and methyl-
diphenylphosphinite [PPh2(OMe)] and ethyldiphenyl-
phosphinite [PPh2(OEt)] (Aldrich), were used as sup-
plied, without any further purification. [ReBr(CO)5]
[36], dimethylphenylphosphonite [PPh(OMe)2] and di-
ethylphenylphosphonite [PPh(OMe)2] were synthesized
by methods reported in Ref. [37].
3.3. Synthesis of mer,trans-[ReBr(CO)3(L)2]
(L=PPh2(OMe) [2a]; L=PPh2(OEt) [2b];
L=PPh(OMe)2 [2c]; L=PPh(OEt)2 [2d])
The mer,trans isomers were obtained easily by fol-
lowing the procedure described for 1a except that the
solvent was toluene and the mixture of [ReBr(CO)5]
and phosphorus ligand was first heated at reflux for 4 h
and then gently stirred for another 18 h room tempera-
ture (r.t.).
Data for 2a. Yield: 84%; m.p. (dec.), 161–180 °C.
Anal. Found: C, 44.8; H, 3.5. Calc for
C29H26BrO5P2Re: C, 44.5; H, 3.4%. FAB MS; m/z (%):
782(19) [M], 754(41) [M−CO], 726(100) [M−2CO],
703(29) [M−Br], 698(13) [M−3CO].
Data for 2b. Yield: 94%; m.p. (dec.), 185 °C (lit.
value 177–182 °C [11]). Anal. Found: C, 45.7; H, 3.6.
Calc. for C31H30BrO5P2Re: C, 45.9; H, 3.7%. EI MS;
m/z (%): 810(21) [M], 782(46) [M−CO], 754(87) [M−
2CO], 731(100) [M−Br], 703(54) [M−(Br,CO)].
Data for 2c. Yield: 60%; m.p. (dec.), 144 °C (lit.
value 145–147 °C [11]). Anal. Found: C, 33.4; H, 3.5.
Calc. for C19H22BrO7P2Re: C, 33.1; H, 3.2%. FAB MS;
m/z (%): 690(16) [M], 662(32) [M−CO], 634(100)
[M−2CO], 606(14) [M−3CO].
Data for 2d. Yield: 82%; m.p. (dec.), 155 °C (lit.
value 155–147 °C [11]). Anal. Found: C, 37.0; H, 4.6.
Calc. for C23H30BrO7P2Re: C, 37.0; H, 4.1%. FAB MS;
m/z (%): 746(14) [M], 718(27) [M−CO], 690(100)
[M−2CO], 662(5) [M−3CO], 645(7) [M−{2CO,
OR}].
Elemental analyses were carried out on a Fisons
EA-1108. Melting points (m.p.) were determined on a
Gallenkamp MFB-595 and are uncorrected. Mass spec-
tra were recorded on a Micromass spectrometer operat-
ing under EI (direct insertion probe, 70 eV, 250 °C) or
FAB (nitrobenzyl alcohol matrix) conditions. IR spec-
tra were recorded on a Bruker Vector 22FT spec-
trophotometer. NMR spectra were obtained on a
Bruker AMX 400 spectrometer; H and 13C{1H} chem-
ical shifts are referred to internal tetramethylsilane
(TMS), and 31P{1H} and 19F{1H} chemical shifts are
reported with respect to 85% H3PO4 or CFCl3.
1
3.2. Synthesis of fac-[ReBr(CO)3(L)2] (L=PPh2(OMe)
[1a]; L=PPh2(OEt) [1b]; L=PPh(OMe)2 [1c];
L=PPh(OEt)2) [1d]
For 1a, 0.3 ml (1.40 mmol) of PPh2(OMe) was added
to a solution of [ReBr(CO)5] (300 mg, 0.74 mmol) in
benzene (20 ml), and the mixture was heated at reflux
for 3 h. The solvent was removed under vacuum and
the resulting oil was stirred with MeOH (4 ml) in an
acetone/N2(I) bath. The white precipitate formed was
then filtered off, washed with MeOH and vacuum
dried. Additional fractions of this compound were ob-
tained by cooling the mother liquor to −18 °C. Com-
pounds 1b–1d were obtained in a similar way, except
that for 1b and 1d precipitation and washing were
performed with EtOH.
3.4. Synthesis of the mer,trans-[Re(H2O)-
(CO)3(L)2][BF4] complexes (3a–3d)
Data for 1a. Yield: 25%; m.p. (dec.), 134 °C. Anal.
Found: C, 44.2; H, 3.2. Calc. for C29H26BrO5P2Re: C,
44.5; H, 3.4%. EI MS; m/z (%): 782(11) [M], 754(11)
[M−CO], 726(16) [M−2CO], 703(29) [M−Br], 675(8)
[M−(Br,CO)].
Data for 1b. Yield: 87%; m.p. (dec.), 151 °C (lit.
value 189–192 °C [11]). Anal. Found: C, 46.0; H, 3.4.
Calc. for C31H30BrO5P2Re: C, 45.9; H, 3.7%. EI MS;
m/z (%): 810(2) [M], 782(10) [M−CO], 754(22) [M−
2(CO)], 731(3) [M−Br], 201(100) [Ph2PO].
For
mer,trans-[Re(H2O)(CO)3{PPh2(OMe)}2][BF4]
(3a), an excess of AgBF4 (150 mg, 0.77 mmol) was
added to a solution of 2a (300 mg, 0.38 mmol) in 22 ml
of a 1:10 water–acetone mixture. The mixture was
refluxed for 1 h, and on cooling to r.t. a black precipi-
tate was formed. The decanted solution was concen-
trated to dryness and the residue was dissolved in 1:1
toluene–ether and cooled to −90 °C. The resulting
grey precipitate was redissolved in CH2Cl2 and this

2380
R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
3.5.1. fac-[ReBr(CO)3(PPh2(OEt)}2] (1b)
solution was filtered through Celite. The filtrate was
concentrated to dryness, the resulting residue was dis-
solved in 3 ml of CH2Cl2/ether, and this solution was
cooled to −90 °C, forming a precipitate that was then
filtered out and vacuum dried. Compounds 3b–3d were
also prepared similarly, except that for 3b the mixture
of AgBF4 and 2b was refluxed for 3 h.
Slow evaporation of the last mother liquor of 3c
yielded pale-pink crystals that elemental analysis and
spectroscopic and diffractometric studies showed to be
[Re(h1-BF4)(CO)3{PPh(OMe)2}2] (4c).
Data for 3a. Yield: 55%; m.p. (dec.), 165 °C. Anal.
Found: C, 43.6; H, 3.4. Calc. for C29H28BF4O6P2Re: C,
43.1; H, 3.5%. FAB MS; m/z (%): 721(12) [M−(BF4)],
703(100) [M−(BF4 H2O)], 675(28) [M−(BF4 H2O,
CO)].
Data for 3b. Yield: 47%; m.p. (dec.), 144 °C. Anal.
Found: C, 44.6; H, 4.2. Calc. for C31H32BF4O6P2Re: C,
44.6; H, 3.9%. FAB MS; m/z (%): 743(6) [M−(BF4)],
731(100) [M−(BF4 H2O)], 703(34) [M−(BF4 H2O,
CO)].
Inspection of the reflections revealed systematic ab-
sences for space groups C2/c or Cc. Solution in the
centro-symmetric group placed the rhenium atom on
the twofold axis (position e in Wyckoff notation), with
a consequent orientational disorder in the bromide and
C(3)ꢀO(3) groups. This was modeled using alternative
sites for each in the 50:50 occupancy ratio. The solution
in the space group Cc showed the same kind of disorder
and the refinement was unstable.
3.5.2. mer,trans-[ReBr(CO)3{PPh(OMe)2}2] (2c)
The crystals of 2c were of poor quality and had
disordered bromide, carbonyl and methyl groups. How-
ever, this was modeled successfully using four alterna-
tive sites with different occupancy factors for the
bromide and carbonyl groups (two with 68% carbonyl
and 32% bromide occupancy and two with 82% car-
bonyl and 18% bromide occupancy). The occupancy
factor of the two methyl sites refined to values close to
50% that were kept fixed in the final run.
All non-H atoms were refined anisotropically except
the carbonyl C and O atoms, for which fixed isotropic
temperature factors were fixed. The ReꢀC and CꢀO
distances were also restrained (DFIX [39]) to about
Data for 3c. Yield: 18%; m.p. (dec.), 112–115 °C.
Anal. Found: C, 32.1; H, 3.4. Calc. for
C15H24BF4O8P2Re: C, 31.9; H, 3.4%. FAB MS; m/z
(%): 629(13) [M−(BF4)], 611(100) [M−(BF4 H2O)],
583(39) [M−(BF4 H2O, CO)].
,
their usual values (2.0 and 1.1 A, respectively).
3.5.3. mer,trans-[ReBr(CO)3{PPh(OEt)2}2] (2d)
Data for 3d. Yield: 27%; m.p. (dec.), 123–125 °C.
Anal. Found: C, 35.6; H, 4.4. Calc. for
C23H32BF4O8P2Re: C, 35.8; H, 4.2%. FAB MS; m/z
(%): 685(7) [M−(BF4)], 607(100) [M−(BF4 H2O)],
639(49) [M−(BF4 H2O, CO)].
Data for 4c. m.p. (dec.), 155–159 °C. Anal. Found:
C, 32.5; H, 3.3. Calc. for C19H22BF4O7P2Re: C, 32.7; H,
3.2%.
The structure of 2d was orientationally disordered
owing to the rhenium atom lying at a center of symme-
try (position c in Wyckoff notation). All non-H atoms
were refined anisotropically except those of the disor-
dered carbonyl group, which were refined isotropically
and had their ReꢀC(3) and C(3)ꢀO(3) restrained to
,
values close to 2.0 and 1.1 A, respectively.
3.5.4. mer,trans-[Re(H2O)(CO)3{PPh2(OMe)}2][BF4]
(3a)
3.5. X-ray data collection, structure and refinement
Data collection at 213 K allowed the location of
hydrogen atoms from Fourier maps. All non-H atoms
were refined anisotropically, and hydrogen atoms
isotropically.
Crystallographic data collection and refinement
parameters are listed in Table 5. Colorless single crys-
tals suitable for X-ray diffractometric studies were ob-
tained by storing the mother liquors at 0 °C (1b, 2c and
2d) or at r.t. (3a and 3b).
Three different diffractometers were used: Enraf–
Nonius CAD4 for 3a and 3b; Enraf–Nonius MACH3
for 1b, 2c and 4c; Bruker Smart CCD for 2d and 3c.
The data were corrected for absorption effects using
C-scans [38a] except for 2d and 3c where an empirical
correction was applied (SADABS [38b]).
3.5.5. mer,trans-[Re(H2O)(CO)3{PPh2(OEt)}2][BF4]
(3b)
All non-H atoms except C(1) and C(2) were refined
anisotropically. H atoms were calculated and refined as
riders except those belonging to the water ligand, which
were located and included in fixed positions with a
common refined Biso.
Structure analyses were carried out by direct methods
[39]. Least-squares full-matrix refinement on F2 was
performed using the program SHELXL-97 [39]. Atomic
scattering factors and anomalous dispersion corrections
for all atoms were taken from Ref. [40]. Graphics were
obtained with ZORTEP [14] and SCHAKAL [41].
3.5.6. mer,trans-[Re(H2O)(CO)3{PPh2(OMe)}2][BF4]
(3c)
All non-H atoms were refined anisotropically. H
atoms were calculated and refined as riders except those
belonging to the water ligand, which were not included.

Table 5
Crystal and structure refinement data
1b
2c
2d
3a
3b
3c
4c
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
C31H30BrO5P2Re
810.60
298
monoclinic
C2/c
13.413(3)
15.229(3)
15.687(3)
90
99.192(18)
90
3163.2(11)
4
5.243
3357
C19H22BrO7P2Re
690.42
298
monoclinic
P21/n
7.483(1)
25.253(4)
13.007(3)
90
102.71(1)
90
C23H30BrO7P2Re
746.52
298
monoclinic
P21/n
10.1110(4)
12.4636(5)
11.0619(5)
90
96.1912(1)
90
1385.88(10)
2
5.979
8947
C29H28BF4O6P2Re
807.46
213
monoclinic
C2/c
23.912(3)
11.6636(5)
22.744(3)
90
104.75(5)
90
6134.4(11)
8
9.317
11120
C
835.52
213
triclinic
P1
10.5016(5)
12.3560(8)
13.9908(7)
94.590(7)
90.629(6)
110.284(5)
1695.91(16)
2
31H32BF4O6P2Re
C19H24BF4O8P2Re
715.33
293
monoclinic
P21/c
9.6620(15)
12.0801(19)
22.719(4)
90
93.479(4)
90
2646.8(7)
4
4.780
14540
C19H22BF4O7P2Re
697.32
293
monoclinic
P21/c
9.5138(10)
14.5048(12)
19.4552(12)
90
94.406(2)
90
2676.8(4)
4
4.721
6634
(
,
a (A)
/
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
2
3
,
V (A )
Z
2397.6(8)
4
6.904
(
Absorption coefficient (mm−1
Reflections collected
Independent reflections
R indices (all data)
)
8.447
6462
6183
7
3217 [Rint=0.0184] 5761 [Rint=0.0719] 3390 [Rint=0.0431] 5170 [Rint=0.0437] 5732 [Rint=0.0465] 5987 [Rint=0.1165] 6449 [Rint=0.0487]
R1=0.0496,
wR2=0.0729
R1=0.0295,
wR2=0.0680
R1=0.2093,
wR2=0.1731
R1=0.0548,
wR2=0.1216
R1=0.0404,
wR2=0.0702
R1=0.0273,
wR2=0.0642
R1=0.0342,
wR2=0.0763
R1=0.0290,
wR2=0.0723
R1=0.0553,
wR2=0.1350
R1=0.0451,
wR2=0.1263
R1=0.1997,
wR2=0.1150
R1=0.0642,
wR2=0.0898
R1=0.2000,
wR2=0.1964
R1=0.0508,
wR2=0.14934
3
Final R indices (I\2|(I))

2382
R. Carballo et al. / Polyhedron 20 (2001) 2371–2383
3.5.7. mer,trans-[Re(p1-BF4)(CO)3{PPh(OMe)2}2] (4c)
Pale-pink crystals of this compound were isolated
after evaporation of solvents from a CHCl3–Et2O solu-
tion of compound 3c. All non-H atoms were refined
anisotropically. H atoms were calculated and refined as
riders.
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The Director, CCDC, 12 Union Road, Cambridge,
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