Preparation and reactivity of hydridorhenium complexes with polypyridine and phosphonite ligands

Article abstract of DOI:10.1002/ejic.200601056

The hydrido complexes [ReH(Cl)(N-N)P₃]BPh₄ [P = PPh-(OEt)₂; N-N = 2,2′-bipyridine (bpy), 5,5′- dimethylbipyridine (5,5′-Me₂bpy), 1,10-phenanthroline (phen)] have been prepared by allowing ReCl₃P₃

Full text of DOI:10.1002/ejic.200601056

FULL PAPER
DOI: 10.1002/ejic.200601056
Preparation and Reactivity of Hydridorhenium Complexes with Polypyridine
and Phosphonite Ligands
Gabriele Albertin,*[a] Stefano Antoniutti,[a] Jesús Castro,[b] Soledad García-Fontán,[b] and
Giorgio Schipilliti[a]
Keywords: Hydrido ligands / P ligands / Protonation / Rhenium / Vinyl complexes
The hydrido complexes [ReH(Cl)(N–N)P3]BPh4 [P = PPh-
(OEt)2; N–N = 2,2Ј-bipyridine (bpy), 5,5Ј-dimethylbipyridine
(5,5Ј-Me2bpy), 1,10-phenanthroline (phen)] have been pre-
pared by allowing ReCl3P3 to react with the polypyridine in
refluxing ethanol. The dihydrido [ReH2(bpy)P3]BPh4 complex
has also been prepared by treating [ReHCl(bpy)P3]+ cation
with NaBH4 in ethanol. Similarly, the hydrido tricarbonyl de-
rivative [ReH2(bpy)(CO)3]BPh4 has been synthesized by al-
lowing [ReH(bpy)(CO)3] to react with HBF4·Et2O. All com-
plexes have been characterized spectroscopically (IR and
NMR spectroscopic data) and the [ReHCl(bpy){PPh-
(OEt)2}3]BPh4 derivative by X-ray crystallography. Proton-
ation of both [ReHCl(bpy)P3]BPh4 and [ReH2(bpy)P3]BPh4
with HBF4·Et2O leads to the classical cations [ReH2Cl-
(bpy)P3]2+ and [ReH3(bpy)P3]2+, respectively. The vinyl com-
plexes [Re{CH=C(H)R}2(bpy)P3]BPh4 (R = Ph, p-tolyl, tert-bu-
tyl) have also been prepared by allowing the dihydrido deriv-
ative [ReH2(bpy)P3]BPh4 to react with an excess of terminal
alkyne in 1,2-dichloroethane.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Re2H8P4, and [ReH4(η2-H2)P3]+ (P = phosphite; n = 1–
4).[11] We have now extended these studies, with the aim of
introducing nitrogen-donor ligands such as 2,2Ј-bipyridine
and 1,10-phenanthroline into rhenium polyhydrido chemis-
try. Our results on the synthesis and reactivity of mixed-
ligand cationic hydridorhenium complexes with phos-
phonite and polypyridine are reported here.
Introduction
The chemistry of rhenium polyhydrido complexes has re-
ceived considerable attention in recent years due to their
various reactivity modes and unusual structural properties,
including the presence of η2-H2 ligands.[1–4] The ancillary
ligands used in this chemistry mainly involve π-acceptors
such as carbonyls and mono- or polydentate tertiary phos-
phane groups.[1–4] In contrast, much less attention has been
devoted to the use of nitrogen-donor ligands, and only one
paper[5] has reported the use of polypyridines as supporting
ligands[6,7] in rhenium polyhydrido complexes. This is some-
what surprising because rhenium complexes with polypyri-
dine ligands are used in photo- and electrocatalytic re-
duction of CO2.[6,7c,8] Changes in the nature of the ancillary
ligands may also greatly change both the properties of com-
plexes and the reactivity of the M–H bond, and recent re-
sults from our laboratory have confirmed the important in-
fluence of polypyridine ligands in the chemistry of classical
and non-classical hydrido complexes of the iron triad.[9]
We have developed the chemistry of hydrido complexes
of transition metals over several years using monodentate
phosphites as supporting ligands.[9,10] Recently, in the case
of rhenium, we reported the synthesis and reactivity of
mono- and polyhydrido complexes of the type [ReH-
(CO)nP5–n], [Re(η2-H2)(CO)nP5–n]+, ReH5P3, ReH3P4,
Results and Discussion
Synthesis of Hydrido Complexes
The trichlorido complex [ReCl3{PPh(OEt)2}3] was
treated with an excess of polypyridine (N–N) in refluxing
ethanol to give the cation [ReHCl(N–N){PPh(OEt)2}3]+,
which was isolated as its BPh4 salt and characterized
(Scheme 1).
Scheme 1. P = PPh(OEt)2; N–N = 2,2Ј-bipyridine (bpy) a, 5,5Ј-
dimethyl-2,2Ј-bipyridine (5,5Ј-Me2bpy) b, 1,10-phenanthroline
(phen) c.
The reaction proceeds with substitution of the chlorido
ligand by the polypyridine and formation of a heptacoord-
inate hydrido cation. The hydrido ligand presumably arises
from abstraction of hydrogen from the ethanol solvent. Al-
though this could not be proved conclusively, numerous
precedents[1a] support this hypothesis.
[a] Dipartimento di Chimica, Università Ca’ Foscari Venezia,
Dorsoduro 2137, 30123 Venezia, Italy
[b] Departamento de Química Inorgánica, Universidade de Vigo,
Facultade de Química, Edificio de Ciencias Experimentais,
36310 Vigo, Galicia, Spain
Eur. J. Inorg. Chem. 2007, 1713–1722
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1713

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán, G. Schipilliti
FULL PAPER
The nature of the phosphane ligand is crucial for the
The rhenium atom in the cation is coordinated by three
synthesis of heptacoordinate hydrido complex 1, which was phosphorus atoms from three phosphonite ligands, two ni-
obtained in pure form only with the phosphonite PPh- trogen atoms from the bipyridine ligand, and a chlorine
(OEt)2. The reaction of the related precursors [ReCl3(P- atom. There is also significant residual electronic density
Ph2OEt)3] with polypyridines gave a mixture of products close to the rhenium atom (at 1.23 Å; see Experimental Sec-
containing only small amounts of the [ReHCl(N–N)- tion), probably due to the presence of the hydrogen atom
(PPh2OEt)3]+ derivatives.
in this region, but unfortunately its position could not be
The hydrido complexes [ReHCl(N–N)P3]BPh4 (1) were refined due to the well-known inability of X-ray dif-
treated with NaBH4 in ethanol to give the dihydrido cations fractometry to detect hydrido ligands coordinated to third-
[ReH2(N–N)P3]+ which, in the case of the bpy ligand, was row transition metals. The presence of this ligand was also
isolated in good yield and characterized (Scheme 2). The confirmed by the values of the angles around the metal,
reaction of 1 with NaBH4 also proceeded with 5,5Ј-dimeth- which are far from the theoretical values for an octahedron
ylpyridine and 1,10-phenanthroline as a ligand but, in these as a consequence of the heptacoordinate environment of
cases, complexes 2 were rather unstable and decomposed the metal. Without knowing the position of the hydrido li-
during crystallization.
gand it is difficult to propose a geometry around the metal.
The N(1)–Re–P(2) axis [171.7(2)°], for example, could indi-
cate a monocapped octahedron or a pentagonal bipyramid.
The chelate angle N(1)–Re–N(2) has a value of only
75.7(4)° Ϫ virtually the same as that found in other 2,2Ј-
bipyridine complexes of ReIII[13] Ϫ and is an important
source of distortion since one of the nitrogen atoms is in
the axis and the other in the equatorial plane. The angles
in the plane for a pentagonal bipyramidal geometry should
be close to 72°, although the different steric requirements
of the hydrido and the rest of the ligands may enlarge these
angles. The angles in the cation complex range from
79.2(2)° to 90.6(1)°. This, and the distortion of the axis,
allows us to propose a monocapped octahedral geometry
around the metal, with the hydrido ligand situated in the
trigonal face occupied by the three phosphorus atoms.
The Re–N [2.172(10) and 2.180(9) Å] and Re–Cl
[2.450(3) Å] bond lengths are slightly longer than those
found for other octahedrally coordinated complexes,[13] as
expected due to the increase in coordination number. The
Re–P bond lengths range from 2.286(3) to 2.365(3) Å and
are slightly shorter than those found in the cationic complex
[ReCl(PhN2){PPh(OEt)2}4]BPh4,[14] the only example of a
Scheme 2. P = PPh(OEt)2; N–N = 2,2Ј-bipyridine (bpy) a.
Hydridorhenium complexes containing polypyridine as a
supporting ligand are rare[5,6] and the only known examples
were obtained from polyhydrido [ReH7(PPh3)2] or
[ReCl(bpy)(CO)3] precursors. The reaction of [ReCl3P3]
with polypyridine in ethanol is therefore a new method for
preparing mixed-ligand hydridorhenium complexes.
Hydrido complexes 1 and 2a are dark-green (1) or red-
brown (2a) solids that are stable in air and in solution in
polar organic solvents, where they behave as 1:1 electro-
lytes.[12] The analytical and spectroscopic (IR, NMR;
Table 1) data confirm the proposed formulation for the
complexes. Further support comes from the X-ray crystal
structure of [ReHCl(bpy){PPh(OEt)2}3]BPh4 (1a), the cat-
ion of which is shown in Figure 1. The geometrical param-
eters of the anion were as expected and do not require fur-
ther comment.
complex containing both ReIII and
a phosphonite
PPh(OEt)2 ligand found in the CCDC (version 5.27, update
August 2006).[15] This shortening is due to the pseudo trans
effect exerted by the nitrogen or chlorine atoms in the hep-
tacoordinate complex when compared with the cited octa-
hedral cation, which has the phosphonite ligands mutually
trans.
The IR spectra of monohydrido complexes [ReHCl(N–
N)P3]BPh4 (1) show the bands characteristic of polypyri-
dine and phosphonite ligands (νPO = 1098–1020 cm–1), but
none attributable to the νReH of the hydrido ligand. How-
1
ever, its presence was confirmed by the H NMR spectra,
which show signals for the PPh(OEt)2 and polypyridine li-
gands and a multiplet between δ = –7.98 and –8.30 ppm
that is characteristic of a hydrido ligand. As the 31P{1H}
NMR spectrum is an A2M multiplet for all complexes 1 in
the temperature range between +20 and –80 °C, the hydrido
1
pattern can be simulated by an A2MX model (X = H),
Figure 1. Perspective view of the crystal structure of the cation
[ReHCl(bpy){PPh(OEt)2}3]+ 1a, with thermal ellipsoids drawn at
the 50% probability level. The ethyl and phenyl groups of the phos-
phites are omitted for clarity.
with the parameters listed in Table 1. In addition, the values
of the two JP,H coupling constants are similar, which sug-
gests that the hydrido is in a mutually cis position with re-
1714
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 1713–1722

Hydridorhenium Complexes
FULL PAPER
1
Table 1. IR, H and 31P{1H} NMR spectroscopic data for rhenium complexes.
Compound
1H NMR[a]
31P{1H} NMR[a,b]
Spin system
δ
Assignment
δ
[ReHCl(bpy){PPh(OEt)2}3]BPh4 (1a)
9.28–6.51 (m)
3.64 (m)
Ph + bpy
CH2
CH3
A2M
δA = 126.8
δM = 119.9
JA,M = 37.7
1.19 (t)
1.16 (t)
1.08 (t)
A2MX
ReH
δX = –8.28
JA,X = 44
JM,X = 58
9.57–6.15 (m)
3.68 (m)
[ReHCl(5,5Ј-Me2bpy){PPh(OEt)2}3]BPh4 (1b)
Ph + bpy
CH2
CH3 bpy
A2M
δA = 126.9
δM = 121.2
JA,M = 36.2
2.34 (s)
2.22 (s)
1.21 (t)
1.19 (t)
1.08 (t)
CH3 phos
ReH
A2MX
δX = –8.30
JAX = 44
JMX = 58
9.64–6.13 (m)
3.70 (m)
[ReHCl(phen){PPh(OEt)2}3]BPh4 (1c)
Ph + phen
CH2
A2M
δA = 127.0
δM = 119.8
JA,M = 37.4
1.28 (t)
CH3
1.03 (t)
A2MX
ReH
δX = –7.98
JA,X = 42
JM,X = 58
9.27–6.86 (m)
3.60 (m)
[ReH2(bpy){PPh(OEt)2}3]BPh4 (2a)
Ph + bpy
CH2
141 m, b
3.31 (m)
0.96 (br. m)
–5.20 (br. m)
9.20–6.80 (m)[c]
3.57 (m)
CH3
ReH
Ph + bpy
CH2
[c]
AM2
δA 145.7
δM 134.3
3.23 (m)
1.25 (t)
0.98 (t)
AM2X2
JA,M = 27.0
CH3
ReH
δX –5.31
JA,X = 12
JM,X = 66
9.03–7.68 (m)
–13.07 d
[ReH2(bpy)(CO)3]BPh4 (3a)[d]
Ph + bpy
ReH2
–17.47 d
JH,H = 3.4
9.55–6.50 (m)[e]
3.75 (m)
1.26 (m)
–5.50 (br. dt)
–7.84 (br. m)
[e]
[ReH2Cl(bpy){PPh(OEt)2}3]2+ (4a)
Ph + bpy
CH2
CH3
AM2
δA = 163.4
δM = 124.1
JA,M = 52.3
δA = 155.0
δM = 125.5
JA,M = 49.4
δA = 127.8
δB = 126.5
JA,B = 31.0
[e]
ReH2
AM2
[ReH3(bpy){PPh(OEt)2}3]2+ (5a)
9.25–6.85 (m)[f]
4.20–3.35 (m)
1.20 (m)
Ph + bpy
CH2
CH3
A2B[f]
–2.2 (br. m)
–3.1 (br. m)
7.30–6.82 (m)
7.08 (m)
6.47 (m)
4.35–3.60 (m)
1.52 (t)
ReH3
[Re{CH=C(H)Ph}2(bpy){PPh(OEt)2}3]BPh4 (6a)
Ph + bpy
=CHα
=CHβ
CH2
AB2
δA = 139.3
δB = 138.2
JA,B = 32.6
CH3
1.15 (t)
1.07 (t)
Eur. J. Inorg. Chem. 2007, 1713–1722
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1715

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán, G. Schipilliti
FULL PAPER
Table 1. (continued)
Compound
1H NMR[a]
31P{1H} NMR[a,b]
Spin system
δ
Assignment
δ
[Re{CH=C(H)-p-tolyl}2(bpy){PPh(OEt)2}3]BPh4 (7a)
9.32–6.86 (m)
AB2XY
(X = Hα, Y = Hβ)
δX = 7.04
Ph + bpy
=CH
AB2
δA = 136.4
δB = 135.2
JA,B = 31.8
δY = 6.45
JA,X = 4.0
JA,Y = 4.35
JB,X = 7.10
JB,Y = 5.20
JX,Y = 7.7
4.30–3.30 (m)
2.44 (s)
CH2
CH3 p-tolyl
CH3 phos
1.51 (t)
1.15 (t)
0.99 (t)
9.28–6.87 (m)
AB2XY
(X = Hα, Y = Hβ)
δX = 7.09
[Re{CH=C(H)-tert-butyl}2(bpy){PPh(OEt)2}3]BPh4 (8a)
Ph + bpy
=CH
AB2
δA = 137.0
δB = 135.5
JA,B = 31.6
δY = 6.51
JA,X = 6.85
JA,Y = 3.60
JB,X = 8.10
JB,Y = 4.30
JX,Y = 8.40
4.32–3.32 (m)
1.50 (t)
CH2
CH3 phos
1.14 (t)
1.10 (t)
1.07 (s)
CH3 tBu
[a] In CD2Cl2 at 25 °C, unless otherwise noted. Chemical shifts are given in ppm and coupling constants in Hz. [b] Positive shifts
downfield from 85% H3PO4. [c] At –30 °C. [d] IR data for the complex in a KBr pellet: νCO = 2049 (s), 1989 (s), 1924 cm–1 (s). [e] At
–50 °C. [f] At –70 °C.
spect to all the phosphonite ligands. Lastly, the two methyl
substituents of the 5,5Ј-dimethyl-2,2Ј-bipyridine ligand are
magnetically inequivalent in 1b (two methyl singlets at δ =
1
2.34 and 2.22 ppm in the H NMR spectrum of the com-
plex).
The geometry of the heptacoordinate hydrido complexes
1 may be discussed in terms of three limiting structures,
namely pentagonal bipyramidal, monocapped octahedral,
or monocapped trigonal prismatic. The spectroscopic data
do not allow us to distinguish between these possible struc-
tures, although it is plausible that the same geometry ob-
served in the solid state for 1a is also maintained in solu-
tion. A monocapped octahedral geometry of type I, which
contains two magnetically equivalent phosphites that are
different from the third and the hydrido ligand in a cis posi-
tion with respect to each of the three phosphite groups, is
in full accordance with the observed NMR spectroscopic
data.
attributable to phosphonite and bpy ligands and a multiplet
at δ = –5.31 ppm for the hydrido ligands. Variable-tempera-
ture T1 measurements (200 MHz) on this signal gave a
T1min value of 104 ms (Table 2), in agreement[16] with the
classical nature of the dihydrido derivative 2a. The hydrido
multiplet at δ = –5.31 ppm can also be simulated with an
AM2X2 (X = 1H) model, with the parameters listed in
1
Table 2. H NMR spectroscopic data (200 MHz; δ values, ppm) in
the hydrido region for some rhenium complexes.
The 1H and 31P NMR spectra of the [ReH2(bpy)P3]+ cat-
ion 2a indicate that the complex is fluxional. The broad
signals present at room temperature in the 31P NMR spec-
trum resolve into an AM2 multiplet at –30 °C, thereby sug-
gesting the presence of two phosphonites that are magneti-
cally equivalent and different from the third. At the same
Compound
T [K]
δ (M–H)
–5.45
T1min [ms]
[ReH2(bpy){PPh(OEt)2}3]BPh4
(2a)
[ReH2(bpy)(CO)3]BPh4 (3a)
[ReH2Cl(bpy){PPh(OEt)2}3]2+ (4a)
[ReH3(bpy){PPh(OEt)2}3]2+ (5a)
205
104
198
200
208
203
–13.1
–7.84
–2.15
–3.10
112
76
65
83
1
temperature, the H NMR spectrum shows sharp signals
1716
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 1713–1722

Hydridorhenium Complexes
FULL PAPER
Table 1, and the good fit between experimental and calcu-
Although the IR and NMR spectroscopic data do not
lated spectra indicates the magnetic equivalence of the two allow us to assign geometries to the complex, a mono-
hydrido ligands. capped octahedral geometry of type III, like those proposed
The spectroscopic data strongly support the proposed for complexes 1 and 2a, fits the spectroscopic data and may
formulation for complex 2a but do not allow us to unam- be tentatively proposed for the [ReH2(bpy)(CO)3]+ deriva-
biguously assign its geometry in solution. However, by tive 3a.
analogy with the related monohydrido 1, a monocapped oc-
tahedral geometry of type II may also be proposed for dihy-
drido complex 2a; this ligand arrangement fits the reported
NMR spectroscopic data.
Reactivity
Protonation of the new hydrido complexes 1, 2a, and 3a
with a Brønsted acid was studied with the aim of testing
The easy synthesis of mono- and dihydridorhenium(III)
whether η2-H2 complexes could be formed. The results
show that, although [ReH2(bpy)(CO)3]+ (3a) is unreactive
towards an excess of HBF4·Et2O, phosphonite complexes
1a and 2a give the new ReV hydrido complexes 4 and 5,
respectively, as shown in Scheme 4.
complexes 1 and 2a prompted us to extend our studies to
related complexes containing carbonyl ligands. The method
used was the protonation of ReI compounds of the type
[ReH(bpy)(CO)3][17] and [ReBr(bpy)(CO)3] (Scheme 3).
Scheme 3.
Although [ReBr(bpy)(CO)3] was found to be unreactive
toward an excess of HBF4, [ReH(bpy)(CO)3] reacts quickly
with HBF4 to give the dihydrido cation [ReH2(bpy)-
Scheme 4. P = PPh(OEt)2.
The protonation was carried out at variable temperature
(CO)3]+, which was isolated as its BPh4 salt and charac- and was monitored by 1H and 31P NMR spectroscopy. The
terized. Good analytical data were obtained for complex 3, addition of HBF4·Et2O to a CD2Cl2 solution of the dihyd-
which is a yellow solid that is stable in air and in solution rido cation [ReH2(bpy)P3]+ (2a) at –80 °C caused the disap-
1
in polar organic solvents, where it behaves as a 1:1 electro- pearance of the hydrido signal at δ = –5.4 ppm in the H
lyte.[12] The IR spectrum of 3a shows three strong absorp- NMR spectrum and the appearance of two new multiplets
tions in the νCO region attributable to three carbonyl li- with an intensity ratio of 2:1 at δ = –2.2 and at –3.1 ppm,
gands in a mutually fac position. Besides the signals of the respectively. Variable-temperature T1 measurements
bpy ligand and the BPh4 anion, the 1H NMR spectrum (Table 2) on these signals gave T1min values (200 MHz) of
shows two doublets at δ = –13.07 and –17.47 ppm (JH,H
=
65 and 83 ms, respectively, which suggests a classical struc-
3.4 Hz) for the two hydrido ligands, which means they are ture for the protonated [ReH3(bpy)P3]+ derivatives. Proton-
magnetically inequivalent. T1 measurements on these hyd- ation of the dihydrido cation [ReH2(bpy)P3]+ therefore pro-
rido signals were also performed and gave T1min values near ceeds by oxidative addition of H+ to the metal center to
112 ms, in good agreement[16] with the classical nature of give the octacoordinate ReV trihydrido derivative 5a. It
these hydrido ligands. On this basis, we hypothesize that the should be noted that a twofold excess of HBF4·Et2O must
reaction of [ReH(bpy)(CO)3] with HBF4 does not proceed be used to complete the formation of 5a, the 31P NMR
by protonation of the Re–H bond to give an η2-H2 ligand spectrum of which shows an A2B multiplet at –80 °C that
but involves the oxidative addition of H+ to yield the formal can be simulated with the parameters listed in Table 1.
cationic ReIII derivative [ReH2(bpy)(CO)3]+. Oxidative ad-
Addition of an excess of NEt3 to a solution of 5a regen-
dition of H+ to a ReI complex is rather rare[3e] as formation erates the starting dihydrido complex [ReH2(bpy)P3]+ and,
of the dihydrogen [Re]-η2-H2 complex is the more usual re- although complex 5a was not isolated, its spectroscopic
sult of protonation.[3i,4a,11b] The presence of the bpy ligand data strongly support its formulation as the mixed-ligand
probably strongly influences the course of the protonation rhenium(V) trihydrido complex [ReH3(bpy)P3]2+, which
reaction that leads to the ReIII species 3.
contains three phosphonites and a bipyridine.
Eur. J. Inorg. Chem. 2007, 1713–1722
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1717

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán, G. Schipilliti
FULL PAPER
Protonation of cationic hydrido complexes has been re-
Vinyl complexes of rhenium are rare[21] and in some cases
ported previously[9,19] and often proceeds, in the presence have been proposed only as intermediates.[22] Our reaction
of a large excess of Brønsted acid, to give η2-H2 derivatives. of dihydrido compound 2a with a terminal alkyne provides
The relatively easy oxidative addition of H+ to a cationic new examples of this class of derivatives. Vinyl complexes
ReIII hydrido complex to yield a ReV polyhydrido complex 6a–8a are green solids that are stable in air and in solution
similar to 5a may be due to the presence of the polypyridine in polar organic solvents, where they behave as 1:1 electro-
ligand, which is able to stabilize classical dicationic hydrido lytes.[12] The analytical and spectroscopic data (Tables 1 and
complexes in a high oxidation state.
3) support their proposed formulation. Thus, besides the
Reaction of the hydrido-chlorido [ReH(Cl)(bpy)P3]+ cat- signals of the polypyridine, phosphites, and the BPh4 anion,
1
ion 1a also proceeds with HBF4·Et2O at –80 °C to give the the H NMR spectrum shows a slightly broad multiplet at
new hydrido cation [ReH2Cl(bpy)P3]2+ (4a) (Scheme 4), al- around δ = 6.45–6.51 ppm due to Hβ of the vinyl ligand.
though in this case a large excess of acid is required to com- This multiplet was correlated in a COSY experiment with
plete the reaction. The 1H and 31P{1H} NMR spectroscopic a signal overlapping the phenyl resonances at δ = 7.04–
data also suggest the presence of two isomers for 4a, which 7.09 ppm, which was attributed to the Hα proton of the
shows two multiplets at δ = –5.50 and –7.84 ppm in the H vinyl ligand. As the 31P NMR spectrum in the temperature
1
NMR spectrum and two A2M multiplets in the 31P NMR range between +20 and –80 °C is an AB2 multiplet, the Hα
spectrum. T1 measurements on the hydrido proton mul- and Hβ vinyl signals can be simulated with an AB2XY (X
tiplets (Table 2) confirmed the classical nature of the pro- = Hα, Y = Hβ) model with the parameters listed in Table 1.
tonated complex, which suggests that oxidative addition of The values of the proton-proton coupling constants JX,Y of
H+ also takes place in the hydrido-chlorido complexes to 7.7 (7a) and 8.4 Hz (8b) also suggest a cis arrangement[23]
yield the rhenium(V) polypyridine derivative 4a. The two of the two vinyl protons.
ReIII hydrido complexes 1a and 2a, which contain a polypy-
ridine and phosphonites as supporting ligands, therefore
Table 3. 13C{1H} NMR spectroscopic data for vinyl complexes 7a
show parallel behavior during the oxidative addition of H+
and 8a.
and afford a dicationic octacoordinate polyhydrido ReV
complex.
Reactivity studies on hydrido cations 1 and 2a were ex-
Compound
13C{1H} NMR[a]
Assignment
δ
7a
165–122 (m)
131.2 (s)
128.6 (m)
67.4 (d)
Ph + bpy
=CHβ
=CHα
CH2
tended to substitution and insertion reactions, and the re-
sults revealed the relatively high stability of both complexes.
Substitution reactions with carbonyl, phosphane, nitrile, or
isocyanide ligands and insertion reactions with unsaturated
molecules such as ArN2+, RCH=CH2, CO2, CS2, etc.
proved impossible for both complexes. However, one reac-
tion was observed for 2a, which reacts with terminal al-
kynes to give the bis(vinyl) derivatives [Re{CH=C(H)-
R}2(bpy)P3]+ (6a, 7a, and 8a), as shown in Scheme 5.
66.4 (d)
16.6 (m)
11.3 (s)
163–122 (m)
129.1 (m)
123.8 (s)
67.4 (m)
65.4 (s)
CH3 phos
CH3 p-tolyl
Ph + bpy
=CHα
=CHβ
CH2
C(CH3)3
C(CH3)3
CH3 phos
8a
30.5 (s)
16.9 (m)
[a] In CD2Cl2 at 25 °C. Chemical shifts are given in ppm and coup-
ling constants in Hz.
Scheme 5. P = PPh(OEt)2; R = Ph 6a, p-tolyl 7a, tert-butyl 8a.
The 13C NMR spectra (Table 3) confirm the presence of
the vinyl group in compounds 6–8 by the presence of a mul-
The reaction is quite slow at room temperature, and the tiplet at δ = 128–129 ppm attributed to Cα and another at
synthesis of pure vinyl complexes 6a–8a can be achieved δ = 123–131 ppm attributed to Cβ of the vinyl ligand.
only at reflux conditions. In every case, the reaction pro- HMQC and HMBC experiments confirmed this assignment
ceeds with the insertion of two alkynes into the Re–H bond as the multiplets at δ = 123–131 ppm in the 13C spectra are
to give only bis(vinyl) derivatives 6a, 7a, and 8a. The correlated to the proton signals near δ = 6.5 ppm due to
absence of any mono-insertion product such as the Hβ vinyl resonance, whereas the 13C signal at δ = 128–
[ReH{CH=C(H)R}2(bpy)P3]+ is probably due to a faster 129 ppm is correlated with the signal at δ = 7.04–7.09 ppm
insertion rate of the second alkyne with respect to the first due the Hα vinyl proton, in agreement with the proposed
into the Re–H bond of 2a. The need for reflux conditions assignment of these signals.
to obtain the vinyl complexes may be explained by the fact
These spectroscopic data strongly support the proposed
that the mechanism proposed[20] for the insertion of an al- formulation for the complexes but do not allow us to unam-
kyne into an M–H bond usually requires a vacant site, and biguously assign geometries to the complexes. Assuming a
only at higher temperatures can the substitution of one li- monocapped octahedral geometry for these vinyl complexes
gand by an alkyne take place.
as well, a structure of type IV, with two magnetically equiv-
1718
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 1713–1722

Hydridorhenium Complexes
FULL PAPER
the complexes in CH3NO2 at 25 °C was measured with a Radiome-
ter CDM 83. Elemental analyses were determined by the Microana-
lytical Laboratory of the Dipartimento di Scienze Farmaceutiche
of the University of Padua, Italy.
alent vinyl groups and two magnetically equivalent phos-
phonites that are different from the third, fits the spectro-
scopic data. However, the absence of any X-ray crystal
structure due to the poor quality of the obtained crystals
means that geometry IV is only a tentative proposal.
Synthesis of Complexes: [ReCl3P3], [ReBr(CO)5], and [ReH(CO)5]
[P = PPh(OEt)2, PPh2OEt] were prepared following the previously
reported methods.[11a,26]
[ReHCl(N–N){PPh(OEt)2}3]BPh4 (1) [N–N = 2,2Ј-bipyridine (bpy)
(a), 5,5Ј-dimethylbipyridine (5,5Ј-Me2bpy) (b), 1,10-phenanthroline
(phen) (c)]: [ReCl3{PPh(OEt)2}3] (0.50 g, 0.56 mmol) and the ap-
propriate polypyridine N–N (1.7 mmol) were placed in a 50-mL,
three-necked, round-bottomed flask and dissolved in 30 mL of eth-
anol. The resulting mixture was refluxed for 5 h and then the sol-
vent was removed under reduced pressure to give a brown solid
from which the hydrido complex was extracted with five 10-mL
portions of CH2Cl2. The combined extracts were evaporated to
dryness to give an oil, which was treated with ethanol (5 mL) con-
taining an excess of NaBPh4 (1.7 mmol, 0.58 g). A dark-green solid
separated out. This solid was filtered and crystallized from CH2Cl2
and ethanol. Yields: 0.45 g for 1a (62%), 0.48 g for 1b (65%), 0.33 g
for 1c (45%).
Conclusions
We have described the synthesis of the mixed-ligand hyd-
ridorhenium(III) complexes [ReHCl(N–N)P3]BPh4 (1) and
[ReH2(N–N)P3]BPh4 (2a), both of which contain phos-
phonite and polypyridine ligands. The hydrido carbonyl
cations [ReH2(bpy)(CO)3]+ have also been obtained by the
oxidative addition of H+ to ReI derivatives. The structural
parameters for the heptacoordinate [ReHCl(bpy)P3]+ cation
have been obtained by X-ray crystallography. Among the
properties shown by the new ReIII hydrido complexes we
can highlight the easy protonation of cationic complexes 1
and 2a to give classical ReV hydrido derivatives, and the
reaction of 2a with terminal alkynes to afford new examples
of vinyl complexes of rhenium.
1a: C64H74BClN2O6P3Re (1292.7): calcd. C 59.47, H 5.77, Cl 2.74,
N
2.17; found
C 59.39, H 5.63, Cl 2.58, N 2.24. ΛM =
54.9 Scm2 mol–1.
1b: C66H78BClN2O6P3Re (1320.7): calcd. C 60.02, H 5.95, Cl 2.68,
2.12; found 59.87, 6.02, Cl 2.80, 2.21. ΛM
51.3 Scm2 mol–1.
N
C
H
N
=
1c: C66H74BClN2O6P3Re (1316.7): calcd. C 65.38, H 5.66, Cl 2.69,
2.13; found 65.16, 5.75, Cl 2.86, 2.05. ΛM
52.8 Scm2 mol–1.
N
C
H
N
=
[ReH2(bpy){PPh(OEt)2}3]BPh4 (2a): [ReCl3{PPh(OEt)2}3] (0.50 g,
0.56 mmol) and 2,2Ј-bipyridine (0.266 g, 1.7 mmol) were placed in
a 50-mL, three-necked, round-bottomed flask and 20 mL of etha-
nol was added. The mixture was stirred and refluxed for 5 h and
then allowed to reach room temperature. An excess of NaBH4
(0.211 g, 5.6 mmol) in ethanol (10 mL) was then added and the
mixture refluxed for 1 h. The solvent was removed under reduced
pressure to give an oil, from which the hydrido complex was ex-
tracted with five 10-mL portions of CH2Cl2. The extracts were
evaporated to dryness to give an oil, which was triturated with etha-
nol (5 mL) containing an excess of NaBPh4 (1.7 mmol, 0.58 g). A
red-brown solid slowly separated out. This solid was filtered and
crystallized from CH2Cl2 and ethanol. Yield: 0.40 g (57%).
C64H75BN2O6P3Re (1258.2): calcd. C 61.09, H 6.01, N 2.23; found
C 61.25, H 5.84, N 2.12. ΛM = 54.7 Scm2 mol–1.
Experimental Section
General: All synthetic work was carried out under an inert atmo-
sphere (Ar, N2) using standard Schlenk techniques or a dry box
(Vacuum Atmospheres, Mecaplex, CH). All solvents were dried
with appropriate drying agents, degassed on a vacuum line, and
distilled into vacuum-tight storage flasks. Re2(CO)10 was a Pressure
Chemical Co. (USA) product, while Re powder was purchased
from Chempur (Germany); both were used as received. The phos-
phonite PPh(OEt)2 and phosphinite PPh2OEt were prepared ac-
cording to Rabinowitz and Pellon.[24] Other reagents were pur-
chased from commercial sources with the highest available purity
and used as received. IR spectra were recorded with a Nicolet
Magna 750 or Perkin–Elmer Spectrum One FT-IR spectrophotom-
eter. NMR spectra (1H, 31P, 13C) were obtained with an AC200 or
Avance 300 Bruker spectrometer at temperatures between –80 and
+30 °C, unless otherwise noted. 1H and 13C NMR spectra are refer-
enced to internal tetramethylsilane; 31P{1H} chemical shifts are re-
ported with respect to 85% H3PO4, with downfield shifts consid-
ered positive. The COSY, HMQC, and HMBC NMR experiments
were performed using the standard programs. Values of T1min
(Ϯ10%) were determined by the inversion recovery method be-
tween –90 and +30 °C in CD2Cl2 with a standard 180°–τ–90° pulse
sequence. The SwaN-MR software package[25] was used to treat
NMR spectroscopic data. The conductivity of 10–3  solutions of
[ReH(bpy)(CO)3]: This compound was prepared by a new method
rather than that reported in the literature.[6] Thus, [ReH(CO)5]
(0.35 mL, 2.05 mmol) and one equivalent of 2,2Ј-bipyridine (0.32 g,
2.05 mmol) were placed in a 250-mL, three-necked, round-bot-
tomed flask and 100 mL of toluene was added. The reaction mix-
ture was refluxed for 4 h and then the solvent was removed under
reduced pressure to give an oil, which was triturated with ethanol
(5 mL). An orange solid slowly separated out from the resulting
stirring solution. This solid was filtered and dried under vacuum.
Yield: 0.307 g (35%). C13H9N2O3Re (427.43): calcd. C 36.53, H
2.12, N 6.55; found C 36.71, H 2.05, N 6.42. IR (KBr): ν = 2032
˜
1
(m), 1976 (s), 1912 cm–1 [s (νCO)]. H NMR (CD2Cl2, 25 °C): δ =
9.13–7.56 (m, bpy), –13.02 (s, ReH) ppm.
[ReBr(bpy)(CO)3]: This compound was prepared by a slight modifi-
cation of the reported method.[27] Thus, [ReBr(CO)5] (1 g,
Eur. J. Inorg. Chem. 2007, 1713–1722
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1719

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán, G. Schipilliti
FULL PAPER
2.46 mmol) and 2,2Ј-bipyridine (1.15 g, 7.38 mmol) were placed in
a 100-mL, three-necked, round-bottomed flask and 30 mL of tolu-
ene was added. The mixture was stirred, refluxed for 5 h, and then
allowed to reach room temperature. A yellow solid separated out
which, after 1 h of stirring, was filtered and dried under vacuum.
Yield: 1.01 g (81%). C13H8BrN2O3Re (506.32): calcd. C 30.84, H
data and structural refinement are given in Table 4 and selected
bond lengths and angles are listed in Table 5.
Table 4. Crystal data and structure refinement for [ReHCl-
(bpy){PPh(OEt)2}3]BPh4 (1a).
Empirical formula
Formula weight
Temperature
C64H74BClN2O6P3Re
1292.68
173(2) K
1.59, N 5.53; found C 30.66, H 1.68, N 5.40. IR (KBr): ν = 2012
˜
1
(m), 1905 (s), 1882 cm–1 [s (νCO)]. H NMR (CD2Cl2, 25 °C): δ =
9.06–7.53 (m, bpy) ppm.
Wavelength
0.71073 Å
Crystal system
Space group
Unit cell dimensions
monoclinic
P21/c
[ReH2(bpy)(CO)3]BPh4 (3a): An excess of HBF4·Et2O (2.3 mmol,
0.33 mL of a 54% solution in diethyl ether) was added to a solution
of [ReH(bpy)(CO)3] (0.100 g, 0.23 mmol) in CH2Cl2 (7 mL) at
–196 °C. The reaction mixture was then brought to room tempera-
ture and stirred for 2 h. The solvent was removed under reduced
pressure to give an oil, which was triturated with ethanol (2 mL)
containing an excess of NaBPh4 (0.46 mmol, 0.157 g). A yellow
solid slowly separated out from the resulting solution. This solid
was filtered and crystallized from CH2Cl2 and ethanol; yield
0.134 g (78%). C37H30BN2O3Re (747.67): calcd. C 59.44, H 4.04,
N 3.75; found C 59.27, H 4.01, N 3.68. ΛM = 53.5 Scm2 mol–1.
a = 14.7335(18) Å
b = 14.7029(19) Å
c = 27.823(4) Å
β = 90.929(4)°
6026.4(13) Å3
4
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
Crystal size
Theta range for data collection
1.421 Mgm–3
2.192 mm–1
2636
0.25ϫ0.16ϫ0.10 mm3
1.38–28.02°
[ReH2(Cl)(bpy){PPh(OEt)2}3]2+
(4a)
and
[ReH3(bpy){PPh- Index ranges
–19 Յ h Յ 19
–13 Յ k Յ 19
–36 Յ l Յ 32
31483
13368 [R(int) = 0.1562]
3916
(OEt)2}3]2+ (5a): These cationic complexes were prepared in
CD2Cl2 solution by protonation of the precursors [ReH(Cl)(bpy)-
P3]BPh4 (1a) and [ReH2(bpy)P3]BPh4 (2a) with HBF4·Et2O. In a
typical experiment, a CD2Cl2 solution (0.5 mL) of 1a or 2a (30–
40 mg, 0.02–0.03 mmol) was placed in a screw-cap 5-mm NMR
tube placed in a dry box. The tube was sealed, cooled to –80 °C,
and then increasing amounts (from one to four equivalents) of
HBF4·Et2O were added with a microsyringe. The tube was then
transferred into the instrument’s probe, which had been pre-cooled
to –80 °C, and the spectra collected.
Reflections collected
Independent reflections
Reflections observed (Ͼ2σ)
Data completeness
0.915
Absorption correction
Semi-empirical from equiva-
lents
1.000 and 0.791
Full-matrix least-squares on
F2
13368/0/709
0.692
R1 = 0.0659, wR2 = 0.0835
R1 = 0.2677, wR2 = 0.1154
1.128 and –1.397 eÅ–3
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I Ͼ 2σ(I)]
R indices (all data)
[Re{CH=C(H)R}2(bpy){PPh(OEt)2}3]BPh4 (6–8) [R = Ph (6a), p-
tolyl (7a), tert-butyl (8a)]: An excess of the appropriate alkyne
RCϵCH (0.8 mmol) was added to
a
solution of
[ReH2(bpy){PPh(OEt)2}3]BPh4 (0.100 g, 0.079 mmol) in 12 mL of Largest diff. peak and hole
1,2-dichloroethane and the reaction mixture refluxed for 1 h. The
solvent was removed under reduced pressure to give an oil, which
was triturated with ethanol (2 mL) containing an excess of NaBPh4
Table 5. Selected bond lengths [Å] and angles [°] for [ReH-
(Cl)(bpy){PPh(OEt)2}3]BPh4 (1a).
(0.2 mmol, 68 mg). A green solid slowly separated out from the
resulting solution. This solid was filtered and crystallized from
CH2Cl2 and ethanol. Yield 0.079 g for 6a (68%), 0.081 g for 7a
(69%), 0.082 g for 8a (73%).
Re–N(2)
Re–P(1)
Re–P(3)
2.172(10)
2.286(3)
2.365(3)
75.7(4)
Re–N(1)
Re–P(2)
Re–Cl(1)
N(2)–Re–P(1)
N(2)–Re–P(2)
P(1)–Re–P(2)
N(1)–Re–P(3)
P(2)–Re–P(3)
N(1)–Re–Cl(1)
P(2)–Re–Cl(1)
2.180(9)
2.316(3)
2.450(3)
80.2(2)
6a: C80H87BN2O6P3Re (1462.5): calcd. C 65.70, H 6.00, N 1.92;
found C 65.49, H 5.93, N 1.88. ΛM = 53.1 Scm2 mol–1.
N(2)–Re–N(1)
N(1)–Re–P(1)
N(1)–Re–P(2)
N(2)–Re–P(3)
P(1)–Re–P(3)
N(2)–Re–Cl(1)
P(1)–Re–Cl(1)
P(3)–Re–Cl(1)
99.9(2)
101.3(3)
87.06(10)
98.7(3)
82.84(10)
84.7(2)
171.7(2)
168.7(3)
110.68(11)
79.2(2)
7a: C82H91BN2O6P3Re (1490.6): calcd. C 66.08, H 6.15, N 1.88;
found C 65.91, H 6.24, N 1.80. ΛM = 54.6 Scm2 mol–1.
8a: C76H95BN2O6P3Re (1422.5): calcd. C 64.17, H 6.73, N 1.97;
found C 64.38, H 6.86, N 2.08. ΛM = 52.8 Scm2 mol–1.
157.02(10)
90.58(10)
87.09(10)
Crystallographic Analysis of [ReHCl(bpy){PPh(OEt)2}3]BPh4 (1a):
Data collection was performed on a SIEMENS Smart CCD area-
detector diffractometer with graphite-monochromated Mo-Kα radi-
ation. Absorption correction was carried out using SADABS.[28]
The structure was solved and refined with the Oscail program[29]
by Patterson methods and refined by a full-matrix least-squares
procedure on F2.[30] Non-hydrogen atoms were refined with aniso-
tropic displacement parameters. Hydrogen atoms were included in
CCDC-626730 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Center via www.ccdc.cam.ac.uk/
data_request/cif.
idealized positions and refined with isotropic displacement param- Acknowledgments
eters except that bonded to the rhenium atom, which was neither
located nor included in the model. Atomic scattering factors and
anomalous dispersion corrections for all atoms were taken from
International Tables for X-ray Crystallography.[31] Details of crystal
Financial support from Ministero dell’Università e della Ricerca
(MIUR) (grant no. PRIN 2004) is gratefully acknowledged. We
also thank Daniela Baldan for technical assistance.
1720
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 1713–1722

Hydridorhenium Complexes
FULL PAPER
4959–4969; f) G. Albertin, S. Antoniutti, E. Bordignon, M. Pe-
goraro, J. Chem. Soc., Dalton Trans. 2000, 3575–3584; g) Al-
bertin, S. Antoniutti, A. Bacchi, B. Fregolent, G. Pelizzi, Eur.
J. Inorg. Chem. 2004, 1922–1938; h) G. Albertin, S. Antoniutti,
M. Bortoluzzi, G. Zanardo, J. Organomet. Chem. 2005, 690,
1726–1738; i) G. Albertin, S. Antoniutti, C. Busato, J. Castro,
S. Garcia-Fontán, Dalton Trans. 2005, 2641–2649.
a) S. Garcia-Fontán, A. Marchi, L. Marvelli, R. Rossi, S. An-
toniutti, G. Albertin, J. Chem. Soc., Dalton Trans. 1996, 2779–
2785; b) G. Albertin, S. Antoniutti, S. Garcia-Fontán, R. Car-
ballo, F. Padoan, J. Chem. Soc., Dalton Trans. 1998, 2071–
2081.
W. J. Geary, Coord. Chem. Rev. 1971, 7, 81–122.
B. Machura, R. Kruszynski, M. Jaworska, P. Lodowski, Poly-
hedron 2005, 24, 701–709.
G. Albertin, S. Antoniutti, A. Bacchi, E. Bordignon, F. Miani,
G. Pelizzi, Inorg. Chem. 2000, 39, 3283–3293.
F. H. Allen, Acta Crystallogr., Sect. B 2002, 58, 380–388.
a) D. G. Hamilton, R. H. Crabtree, J. Am. Chem. Soc. 1988,
110, 4126–4136; b) M. T. Bautista, K. A. Earl, P. A. Maltby,
R. H. Morris, C. T. Schweitzer, A. Sella, J. Am. Chem. Soc.
1988, 110, 7031–7036; c) P. J. Desrosiers, L. Cai, Z. Lin, R.
Richards, J. Halpern, J. Am. Chem. Soc. 1991, 113, 4173–4184.
We have prepared the [ReH(bpy)(CO)3] complex by substitut-
ing carbonyl ligands with bpy in the pentacarbonyl derivative
[ReH(CO)5]. A mer arrangement of the three CO ligands is
suggested by the presence of one band of medium intensity
(2032 cm–1) and two strong ones (1976 and 1912 cm–1) in the
νCO region,[18] while the presence of the hydrido ligand is con-
firmed by the sharp singlet at δ = –13.02 ppm observed in the
1H NMR spectrum. The previously reported species
[ReH(bpy)(CO)3][6] was prepared from the [Re(bpy)(CO)3-
(H2O)]+ cation and showed a fac geometry with the hydrido
signal surprisingly being found at δ = +1.54 ppm in the 1H
NMR spectrum. Such a high frequency assignment for the hyd-
rido is questionable.
[1]
a) E. L. Muetterties, Transition Metal Hydrides, Marcel
Dekker, Inc., New York, 1971; b) A. Dedieu, Transition Metal
Hydrides, Wiley-VCH, New York, 1992; c) M. Peruzzini, R.
Poli, Recent Advances in Hydride Chemistry, Elsevier, Amster-
dam, 2001; d) G. J. Kubas, Metal Dihydrogen and σ-Bond Com-
plexes, Kluwer Academic, Plenum Publishers, New York, 2001.
a) P. Jessop, R. H. Morris, Coord. Chem. Rev. 1992, 121, 155–
284; b) D. M. Heinekey, W. J. Oldham Jr, Chem. Rev. 1993, 93,
913–926; c) R. H. Crabtree, Angew. Chem. Int. Ed. Engl. 1993,
32, 789–805.
a) D. R. Root, K. E. Meyer, R. A. Walton, Inorg. Chem. 1989,
28, 2503–2506; b) F. A. Cotton, R. L. Luck, D. R. Root, R. A.
Walton, Inorg. Chem. 1990, 29, 43–47; c) M. T. Costello, P. E.
Fanwick, M. A. Green, R. A. Walton, Inorg. Chem. 1992, 31,
2359–2365; d) X. L. R. Fontaine, E. H. Fowles, T. P. Leyzell,
B. L. Shaw, M. Thornton-Pett, J. Chem. Soc., Dalton Trans.
1991, 1519–1524; e) X.-L. Luo, D. Michos, R. H. Crabtree, In-
org. Chem. 1991, 30, 4286–4288; f) D. Michos, X.-L. Luo,
J. A. K. Howard, R. H. Crabtree, Inorg. Chem. 1992, 31, 3914–
3916; g) X. L. R. Fontaine, T. P. Layzell, B. L. Shaw, J. Chem.
Soc., Dalton Trans. 1994, 917–924; h) M. Leeaphon, K. Rohl,
R. J. Thomas, P. E. Fanwick, R. A. Walton, Inorg. Chem. 1993,
32, 5562–5568; i) D. G. Gusev, D. Nietlispach, I. L. Eremenko,
H. Berke, Inorg. Chem. 1993, 32, 3628–3636; j) Y. Kim, H.
Deng, J. C. Gallucci, A. Wojcicki, Inorg. Chem. 1996, 35, 7166–
7173; k) Z. Lin, M. B. Hall, J. Am. Chem. Soc. 1994, 116, 4446–
4448.
a) D. M. Heinekey, C. E. Radzewich, M. H. Voges, B. M.
Schomber, J. Am. Chem. Soc. 1997, 119, 4172–4181; b) T. M.
McKinney, P. E. Fanwick, R. A. Walton, Inorg. Chem. 1999,
38, 1548–1554; c) N. V. Belkova, E. S. Shubina, A. V. Ionidis,
L. M. Epstein, H. Jacobsen, A. Messmer, H. Berke, Inorg.
Chem. 1997, 36, 1522–1525; d) J. Huhmann-Vincent, B. L.
Scott, G. J. Kubas, J. Am. Chem. Soc. 1998, 120, 6808–6809; e)
S. Bolaño, L. Gonsalvi, P. Barbaro, A. Albinati, S. Rizzato, E.
Gutsul, N. Belkova, L. Epstein, E. Shubina, M. Peruzzini, J.
Organomet. Chem. 2006, 691, 629–637.
G. A. Moehring, R. A. Walton, Inorg. Chem. 1987, 26, 2910–
2912.
B. P. Sullivan, T. J. Meyer, J. Chem. Soc., Chem. Commun. 1984,
1244–1245.
The organometallic chemistry of rhenium polypyridine com-
plexes is also relatively undeveloped, see: a) J. Guilhem, C. Pas-
card, J.-M. Lehn, R. Ziessel, J. Chem. Soc., Dalton Trans. 1989,
1449–1454; b) J. V. Caspar, B. P. Sullivan, T. J. Meyer, Inorg.
Chem. 1984, 23, 2104–2109; c) D. H. Gibson, X. Yin, H. He,
M. S. Mashuta, Organometallics 2003, 22, 337–346.
a) J. Hawecker, J.-M. Lehn, R. Ziessel, J. Chem. Soc., Chem.
Commun. 1983, 536; b) B. P. Sullivan, C. M. Bolinger, D. Con-
rad, T. J. Vining, T. J. Meyer, J. Chem. Soc., Chem. Commun.
1985, 1414; c) P. Christensen, A. Hamnett, A. V. G. Muit, G. A.
Timney, J. Chem. Soc., Dalton Trans. 1992, 1455; d) G. J. Stor,
F. Hartl, J. W. M. van Outersterp, D. J. Stufkens, Organometal-
lics 1995, 14, 115; e) F. P. A. Johnson, M. W. George, F. Hartl,
J. J. Turner, Organometallics 1996, 15, 3374; f) A. Klein, C.
Vogler, W. Kaim, Organometallics 1996, 15, 236.
a) G. Albertin, S. Antoniutti, M. Bortoluzzi, Inorg. Chem.
2004, 43, 1328–1335; b) G. Albertin, S. Antoniutti, A. Bacchi,
C. DЈEste, G. Pelizzi, Inorg. Chem. 2004, 43, 1336–1349; c) G.
Albertin, S. Antoniutti, S. Pizzol, J. Organomet. Chem. 2004,
689, 1639–1647.
a) S. Antoniutti, G. Albertin, P. Amendola, E. Bordignon, J.
Chem. Soc., Chem. Commun. 1989, 229–230; b) P. Amendola,
S. Antoniutti, G. Albertin, E. Bordignon, Inorg. Chem. 1990,
29, 318–324; c) G. Albertin, P. Amendola, S. Antoniutti, E.
Bordignon, J. Chem. Soc., Dalton Trans. 1990, 2979–2984; d)
G. Albertin, S. Antoniutti, D. Baldan, E. Bordignon, Inorg.
Chem. 1995, 34, 6205–6210; e) G. Albertin, S. Antoniutti, M.
Bettiol, E. Bordignon, F. Busatto, Organometallics 1997, 16,
[11]
[2]
[3]
[12]
[13]
[14]
[15]
[16]
[17]
[4]
[18]
[19]
D. A. Adams, Metal-ligand and Related Vibrations, St. Martin’s
Press, New York, 1968.
[5]
[6]
[7]
a) M. Schlaf, A. J. Lough, P. A. Maltby, R. H. Morris, Organo-
metallics 1996, 15, 2270–2278; b) E. Rocchini, A. Mezzetti, H.
Rügger, U. Burckhardt, V. Gramlich, A. Dal Zotto, P. Mar-
tinuzzi, P. Rigo, Inorg. Chem. 1997, 36, 711–720; c) T. A. Lu-
ther, D. M. Heinekey, Inorg. Chem. 1998, 37, 127–132; d) S. E.
Landau, R. H. Morris, A. J. Lough, Inorg. Chem. 1999, 38,
6060–6068; e) K. T. Smith, M. Tilset, R. Kuhlman, K. G. Caul-
ton, J. Am. Chem. Soc. 1995, 117, 9473–9480.
X. Li, T. Vogel, C. D. Incarvito, R. H. Crabtree, Organometal-
lics 2005, 24, 62–76 and references cited therein.
W. G. Hatton, J. A. Gladysz, J. Am. Chem. Soc. 1983, 105,
6157–6158.
M. Leeaphon, A. L. Ondracek, R. J. Thomas, P. E. Fanwick,
R. A. Walton, J. Am. Chem. Soc. 1995, 117, 9715–9724.
a) J. Navarro, E. Sola, M. Martin, I. T. Dobrinovitch, F. J. La-
hoz, L. A. Oro, Organometallics 2004, 23, 1908–1917; b) M.
Bassetti, S. Marini, J. Diaz, M. P. Gamasa, J. Gimeno, Y. Rod-
riguez-Alvarez, S. Garcia-Granda, Organometallics 2002, 21,
4815–4822; c) Y. Gao, M. C. Jennings, R. L. Puddephatt, Dal-
ton Trans. 2003, 261–265; d) D. S. Frohnapfel, P. S. White, J. L.
Templeton, Organometallics 2000, 19, 1497–1506; e) M. L.
Buil, M. A. Esteruelas, Organometallics 1999, 18, 1798–1800;
f) X. Li, L. N. Appelhans, J. W. Faller, R. H. Crabtree, Organo-
metallics 2004, 23, 3378–3387; g) I. de los Rios, M. Jimenez-
Tenorio, M. C. Puerta, P. Valerga, J. Am. Chem. Soc. 1997, 119,
6529–6538; h) Y. Wakatsuki, N. Koga, H. Werner, K. Morok-
uma, J. Am. Chem. Soc. 1997, 119, 360–366.
[20]
[21]
[22]
[23]
[8]
[9]
[10]
[24]
[25]
[26]
[27]
R. Rabinowitz, J. Pellon, J. Org. Chem. 1961, 26, 4623–4626.
G. Balacco, J. Chem. Inf. Comput. Sci. 1994, 34, 1235–1241.
M. A. Urbancic, J. R. Shapley, Inorg. Synth. 1990, 28, 165–168.
E. W. Abel, G. Wilkinson, J. Chem. Soc. 1959, 1501–1505.
Eur. J. Inorg. Chem. 2007, 1713–1722
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1721

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán, G. Schipilliti
FULL PAPER
[28] G. M. Sheldrick, SADABS, An empirical absorption correction
program for area detector data, University of Göttingen, Ger-
many, 1996.
[29] P. McArdle, J. Appl. Crystallogr. 1995, 28, 65.
[30] G. M. Sheldrick, Shelxl97. Program for the solution and refine-
ment of crystal structures, University of Göttingen, Germany,
1997.
[31] International Tables for X-ray Crystallography, vol. C, Kluwer,
Dordrecht, The Netherlands, 1992.
Received: November 10, 2006
Published Online: March 9, 2007
1722
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 1713–1722