The synthesis, spectroscopic investigation, crystal and molecular structure of [ReCl3(MeCN)(dppe)] complex

Article abstract of DOI:10.1016/S1387-7003(03)00107-2

The [ReOCl₃(dppe)] complex reacts with acetonitrile in the presence of excess of triphenylphosphine to give a new monomeric nitrile rhenium(III) complex - [ReCl₃MeCN)(dppe)] (1). This paper presents spectroscopic characterization, magnetochemical measurements, crystal and molecular structure for 1.

Full text of DOI:10.1016/S1387-7003(03)00107-2

Inorganic Chemistry Communications 6 (2003) 786–789
www.elsevier.com/locate/inoche
The synthesis, spectroscopic investigation, crystal and
molecular structure of [ReCl3ðMeCNÞðdppeÞ] complex
a
a,
b
B. Machura , J.O. Dziꢀegielewski *, J. Kusz
Department of Inorganic and Radiation Chemistry, Institute of Chemistry, University of Silesia, 9th Szkolna Street, Katowice 40-006, Poland
a
b
Institute of Physics, University of Silesia, 4th Uniwersytecka Street, Katowice 40-006, Poland
Received 3 February 2003; accepted 20 February 2003
Abstract
The [ReOCl3ðdppeÞ] complex reacts with acetonitrile in the presence of excess of triphenylphosphine to give a new monomeric
nitrile rhenium(III) complex – [ReCl3ðMeCNÞðdppeÞ] (1). This paper presents spectroscopic characterization, magnetochemical
measurements, crystal and molecular structure for 1.
Ó 2003 Elsevier Science B.V. All rights reserved.
Keywords: Rhenium; Acetonitrile; Nitrile complexes; X-ray structure
1. Introduction
coordination sphere. Here we present the synthesis
method of the novel nitrile rhenium(III) complex
[ReCl3ðMeCNÞðdppeÞ] (1), its spectroscopic character-
ization, crystal and molecular structure.
Nitrile transition metal complexes have been recog-
nized as convenient substrates in the synthesis of orga-
nometallic derivatives for many years. RACBN ligand,
which has weak r donor and p acceptor ability can be
readily displaced by other isoelectronic unsaturated li-
gands [1–5] or can be converted into other organic li-
gands in such chemical processes as insertion,
nucleophilic and electrophilic attack [1,6–9].
The interest in nitrile compounds results also from
structural aspects of coordinated RACBN molecules,
which can interact with metal centers in several different
ways, as: (i) terminal r-bonded, g1-NCR, (ii) p-bonded,
g2-NCR or (iii) bridging, r; p-bonded, l-g1, g2-NCR
[1–9].
2. Experimental
Triphenylphosphine, bis(diphenylophosphino)ethane
(dppe) and ammonium perrhenate were purchased from
Aldrich Chemical and used without further purification.
Solvents were obtained from commercial sources and
thoroughly deoxygenated prior to use. The reaction was
performed under argon atmosphere. [ReOCl3ðdppeÞ]
was prepared according to the literature method [11].
The finding that [ReCl3ðPPh3Þ2], generated in situ
from [ReOCl3ðPPh3Þ2] and PPh3, undergoes a direct
reaction with the triazenido anion Li(RNAN@NR) to
give trans-[ReCl2ðPPh3Þ2(RNANANR)] [10] prompted
us to explore the reaction of [ReOCl3ðdppeÞ] with ace-
tonitrile in the presence of excess of triphenylphosphine
as a direct route to the monomeric rhenium complex
with acetonitrile and bis(diphenylophosphine)ethane in
2.1. Preparation of ½ReCl3ðMeCNÞðdppeފ ð1Þ
Triphenylphosphine (5 g, 19 mmol) was added to a
suspension of [ReOCl3ðdppeÞ] (1 g, 1.4 mmol) in tetra-
hydrofurane (50 ml) and acetonitrile (50 ml). The
brownish-orange solution thus formed was refluxed for
4 h. The volume was condensed to 15 ml and upon slow
cooling to room temperature brownish-orange micro-
crystalline precipitate was isolated. X-ray quality crys-
tals were obtained by recrystallization from acetonitrile.
Yield 70%.IR (KBr, cmÀ1) 3062 (w), 2888 (w), 1485 (m),
* Corresponding author. Tel.: +48-32-258-2441; fax: +32-259-9978.
E-mail address: jod@tc3.ich.us.edu.pl (J.O. Dzioꢀegielewski).
1387-7003/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S1387-7003(03)00107-2

B. Machura et al. / Inorganic Chemistry Communications 6 (2003) 786–789
787
1434 (s), 1407 (m), 1312 (w), 1186 (w), 1161 (w), 1103 (s),
1027 (w), 996 (w) 871 (w), 801 (w), 782 (s), 743 (s), 692
(s), 647 (m), 526 (s), 513 (m), 477 (m).
Anal. found: C, 49.82; H, 3.75; N, 1.85. Calc. for
C28H27Cl3NP2Re (1): 45.94; H, 3.72; N, 1.91.
corrections were applied. The structures were solved by
means of the Patterson and Fourier methods. All the
non-hydrogen atoms were refined anisotropically using
full-matrix, least-squares technique. The hydrogen at-
oms of the phenyl rings were treated as ‘‘riding’’ on their
ꢀ
parent carbon atoms [d(CAH) ¼ 0.96 A] and assigned
2.2. Physical measurements
isotropic temperature factors equal to 1.2 times the va-
lue of equivalent temperature factor of the parent car-
bon atom. SHELXL97 [12] and SHELXTL [13]
programs were used for all the calculations.
UV–Vis spectra were recorded on a spectrophotom-
eter Lab Alliance UV–Vis 8500 in the range 800–220 nm
in deoxygenated dichloromethane solution. IR spectra
were recorded as KBr pellets with a Nicolet Magna 560
spectrophotometer in the spectral range 4000–400 cmÀ1
.
3. Results and discussion
The magnetic susceptibility was determined with a su-
perconducting quantum interference device (SQUID,
Quantum Design) magnetometer. Elemental analyses (C
H N) were performed on a Perkin–Elemer CHN-2400
analyzer.
The [ReCl3ðMeCNÞðdppeÞ] complex has been pre-
pared in high yield by use of the procedure shown in Eq.
(1).
½ReOCl3ðdppeފ þ MeCN þ PPh3
! ½ReCl3ðMeCNÞðdppeފ þ OPPh3
ð1Þ
2.3. Crystal structures determination and refinement
It can be assumed that the [ReCl3ðdppeÞ] compound,
generated from [ReOCl3ðdppeÞ] and PPh3 in the first
step of the synthesis, reacts with MeCN to give
[ReCl3ðMeCNÞðdppeÞ]. The mass ratio of [ReOCl3
ðdppeÞ] and PPh3 equal to 1:5 ensures the maximum
yield of 1. In the case of smaller excess of PPh3, some
unreacted starting material has been recovered from the
reaction.
The X-ray intensity data were collected on a Kuma
KM-4 diffractometer with x À 2h scan mode. Details
concerning crystal data and refinement are given in
Table 1. Lorentz polarization, empirical absorption
Table 1
Crystal data and structure refinement for 1
The rhenium atom in 1 is in a distorted octahedral
environment with terminal NACACH3 group [Re-
ANAC angle – 176.0(8)°] trans to one of the phosphorus
atoms of the chelate ligand and three halide ligands in
meridional geometry (Fig. 1). The departure from the
ideal octahedron is induced mainly by the chelate ligand
and partially by two weak intramolecular hydrogen
bonds: Cð6ÞAHð6AÞ Á Á Á Clð1Þ and Cð18ÞAHð18AÞ Á Á Á
1
Empirical formula
Formula weight
Temperature
C28H27Cl3NP2Re
732.00
293(2) K
ꢀ
0.71073 A
Wavelength
Crystal system
Space group
Unit cell dimensions
Monoclinic
P21=n
ꢀ
a ¼ 9:5270ð10Þ A
ꢀ
ꢀ
b ¼ 22:511ð4Þ A
Nð1Þ (D Á Á Á A distance 3.646(12) and 3.392(14) A and
b ¼ 102:44ð3Þ°
DAH Á Á Á A angle 148.2° and 137.2°, respectively). The
ꢀ
c ¼ 13:598ð3Þ A
ꢀ3
Volume
Z
2847:8ð9Þ A
4
Density (calculated)
Absorption coefficient
F(0 0 0)
1:707 Mg=m3
4:679 mmÀ1
1432
Crystal size
h range for data collection
Index ranges
0:26 Â 0:26 Â 0:13 mm
1.78–26.07°
À11 6 h 6 0
À27 6 k 6 0
À16 6 l 6 16
5968
Reflections collected
Independent reflections
Max. and min. transmission
Data/restraints/parameters
Goodness-of-fit on F 2
5624 ðRint ¼ 0:0384Þ
0.5814 and 0.3759
5624/0/318
1.240
Final R indices [I > 2rðIÞ]
R1 ¼ 0:0495
wR2 ¼ 0:0932
R1 ¼ 0:0949
wR2 ¼ 0:1206
R indices (all data)
ꢀÀ3
Fig. 1. The molecular structure of 1. The thermal ellipsoids are drawn
at 50% probability level.
Largest diff. peak and hole
1.592 and À1:307 e A

788
B. Machura et al. / Inorganic Chemistry Communications 6 (2003) 786–789
Table 2
The complex 1 shows room temperature magnetic
moment of 1.41 BM. This value is characteristic of
mononuclear complexes with low-spin rhenium(III) (d4)
ions in Oh field [23] and arises because of the large spin–
orbit coupling (n ¼ 2500 cmÀ1) [24]. The variation of
the magnetic susceptibility with temperature of 1 in the
solid state is shown in Fig. 2. Temperature-independent
paramagnetism should be characteristic of d4 systems in
octahedral environments [25] and has been confirmed
for some of rhenium(III) and osmium(IV) halide com-
plexes [24,26–28].
The positions and molar absorption coefficients of
electronic bands for 1 and the electronic transitions as-
signed to the bands are shown in Table 3. The data of
Table 3 prove a pseudo-octahedral configuration of
complex 1. Comparatively high values of molar extinc-
tion coefficient of the bands connected with intercombi-
nation electron transitions, result from high spin–orbital
coupling (k ¼ 3316 cmÀ1). As a result of the coupling,
term 3T1 splits into singlet terms mixed with 3T1. Because
of this fact, intercombination electron transitions have to
a certain degree the character of singlet–singlet transi-
tions. Pure triplet ground state (3T1) exists at very low
ꢀ
Bond lengths (A) and angles (°) for 1
Bond lengths
Angles
Re(1)AN(1)
Re(1)AP(1)
Re(1)AP(2)
Re(1)ACl(1)
Re(1)ACl(2)
Re(1)ACl(3)
N(1)AC(27)
C(27)AC(28)
P(1)AC(1)
2.121(8)
2.387(3)
2.388(3)
2.452(2)
2.332(2)
2.334(2)
1.105(12)
1.475(15)
1.813(10)
1.810(12)
1.869(12)
1.882(10)
1.811(11)
1.844(10)
N(1)ARe(1)ACl(2)
N(1)ARe(1)ACl(3)
Cl(2)ARe(1)ACl(3)
N(1)ARe(1)AP(1)
Cl(2)ARe(1)AP(1)
Cl(3)ARe(1)AP(1)
N(1)ARe(1)AP(2)
Cl(2)ARe(1)AP(2)
Cl(3)ARe(1)AP(2)
P(1)ARe(1)AP(2)
N(1)ARe(1)ACl(1)
Cl(2)ARe(1)ACl(1)
Cl(3)ARe(1)ACl(1)
P(1)ARe(1)ACl(1)
P(2)ARe(1)ACl(1)
C(27)AN(1)ARe(1)
N(1)AC(27)AC(28)
89.3(2)
90.1(2)
175.22(9)
178.7(2)
90.46(10)
90.04(9)
95.4(2)
90.32(9)
85.01(9)
83.33(9)
85.1(2)
P(1)AC(7)
P(1)AC(26)
P(2)AC(13)
P(2)AC(25)
P(2)AC(19)
91.98(9)
92.70(9)
96.20(9)
177.66(9)
176.0(8)
177.9(12)
most important bond length and angles for 1 are re-
ported in Table 2. The ReAN(nitrile) bond lengths of
2.121(8) A in 1 agrees well with ReAN values found in
ꢀ
rhenium complexes containing nitrile ligand in trans
position to strong p-acceptor, but it is significantly
longer than ReAN bond lengths found for complexes in
which trans position to nitrile ligand is not occupied by
p-acceptor. In [ReBr3ðNOÞðMeCNÞðPPh3Þ] [14] and
½NEt4Š½ReBr4ðNOÞðMeCNފ [15] with acetonitrile trans
to nitrosyl group the ReAN(nitrile) bond lengths are
ꢀ
equal to 2.156(7) and 2.153(11) A, respectively, but in
mer-trans-[ReCl3ðMeCNÞðPPh3Þ2] the ReAN distance
ꢀ
equals to 2.068(5) A [16].
A clear trans effect of dppe ligand is also observed in
the elongation of ReACl distance trans to phosphorus
atom of the dppe ligand. The ReACl(1) bond trans to
ꢀ
phosphine ligand at 2.452(2) A is longer than the mu-
tually trans ReACl bonds equal to 2.332(2) and 2.334(2)
ꢀ
ꢀ
A. The ReAP distances at 2.387(3) and 2.388(3) A are
considerably shorter than those found in the rhenium
complexes with chelate phosphine ligands: 2.450(4),
0
ꢀ
2.456(4) and 2.480(4) A in mer-[ReCl3(dppm-P,P )
ꢀ
(dppom-P)] [17] and 2.479(1) and 2.458(2) A in trans-
Fig. 2. The variation of the magnetic susceptibility with temperature
for 1.
2þ
½ReClðNOÞðdppeÞ2Š [18]. The significant shortening of
ꢀ
the CAN bond length [1.105(12) A] in comparison with
ꢀ
free acetonitrile [1.155 A] [19] is observed and it is ex-
Table 3
Band positions, molar absorption coefficients and assignments for 1
pected upon coordination. The NCACH3 distance is
within the range observed for other acetonitrile com-
plexes [14–16].
The IR spectra of 1 is governed by the vibrations of
the phosphine ligand. The mðCBNÞ vibration is absent,
as already noted for other monomeric rhenium(III) ni-
trile complexes [20–22]. However, the absence of the
characteristic strong m(Re@O) band at ꢀ970 cmÀ1 is
clear indication that there is no oxo-Re(V) starting
material left in 1 [11].
Band position (cmÀ1
)
e
Assignment
5
14 025
22 625
26 525
33 300
36 630
37 450
38 315
43 100
32
195
3T1 ! E
1
3T1 ! T2
3
735
6575
3T1 ! E
3
3T1 ! T2
12 650
14 260
14 300
71 630
p0ClÀ ! 5dRe
p0ClÀ ! 5dRe
5dRe ! pꢁNBCAR
pbC ! 3dP; p ! pꢁ
6H5
e ¼ molar absorption coefficient (dm3 molÀ1 cmÀ1).

B. Machura et al. / Inorganic Chemistry Communications 6 (2003) 786–789
789
[4] R.H.T. Bleijerveld, K. Vrieze, Inorg. Chim. Acta 19 (1976)
195.
temperature, and that is why leff ¼ 1:41 BM is signifi-
cantly lower than 2.83 BM, and the magnetic suscepti-
bility does not depend on temperature. EPR signals of
complex 1 at room temperature are not observed because
of the same effect. The existence of p bond in ReAPdppe
group (proven by longer ReACl in trans position to-
wards the phosphine ligand, in comparison with the
other ReACl bonds), proves a transfer of electron den-
sity from 5dRe to 3dP. The transfer has no manifestation
in the absorption bands. Identical ReAP(1) and ReAP(2)
bond lengths show the comparable p-acceptor abilities
of PPh3 and NBCAMe.
[5] J. Chantler, P.E. Fanwick, R.A. Walton, J. Organomet. Chem.
604 (2000) 219.
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(1996) 299.
[7] W. Kaim, M. Moscherosch, Coord. Chem. Rev. 129 (1994)
157.
ꢁ
[8] M.C. Fatima, G. da Silva, J.J.R.F. da Silva, A.J.L. Pombeiro,
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[9] J. Chantler, P.E. Fanwick, R.A. Walton, Inorg. Chim. Acta 305
(2000) 215.
[10] R. Rossi, A. Duatti, L. Magon, U. Casellato, R. Graziani, L.
Tonialo, J. Chem. Soc., Dalton Trans (1982) 1949.
[11] G. Rouschias, G. Wilkinson, J. Chem. Soc. A 465 (1966).
[12] G.M. Sheldrick, SHELXL97. Program for the Solution and
The values of the 10 Dq ligand field parameter and
RacahÕs parameters – B and C, calculated on the basis of
the positions and molar extinction coefficients of elec-
tronic bands are equal to 2652, 431 and 1983 cmÀ1, re-
spectively.
€
Refinement of Crystal Structures, University of Gottingen,
Germany, 1997.
[13] G.M. Sheldrick, SHELXTL: release 4.1 for Siemens Crystallo-
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[14] T.J. Bartczak, W. Czurak, J.O. Dziegielewski, B. Machra, Polish
z
J. Chem. 72 (1998) 633.
[15] G. Ciani, D. Giusto, M. Manassero, M. Sansoni, J. Chem. Soc.,
Dalton (1975) 2156.
Supplementary data
[16] M. Davis, F. Belanger-Gariepy, D. Zargarian, A.L. Beauchamp,
Acta Cryst. C 53 (1997) 428.
Supplementary data of [ReCl3ðMeCNÞðdppeÞ] com-
plex are available from the CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK on request, quoting the de-
position number 203627.
[17] X.L.R. Fontaine, E.H. Fowless, T.P. Layzell, B.L. Shaw,
M. Thornton-Pett, J. Chem. Soc., Dalton Trans. (1991)
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Acknowledgement
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[24] A. Earnshaw, B.N. Figgis, J. Lewis, R.D. Peacock, J. Chem. Soc.
(1961) 3132.
The authors thank G. Jakob from University of
Mainz for magnetic measurement.
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