Rhenium and technetium complexes with diphenyl(2-pyridyl)phosphine

Article abstract of DOI:10.1016/S0277-5387(99)00216-8

The potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh₂py) reacted with (NEt₄)₂[M^IX₃(CO)₃] complexes (M=Re, Tc; X=Cl, Br) to give (NEt₄)[M^IX₂(CO)₃(PPh ₂py-P)] or [M^IX(CO)₃(PPh₂py-P)₂] depending on the amount of the ligand used. The reaction with (NBu₄)[Tc^VINCl₄] yielded [Tc^VNCl₂(PPh₂py-P)₂] whereas from the reaction with (NBu₄)[ReOCl₄] the complexes [Re^VOCl₃(PPh₂py-P,N)], [Re^VOCl₃(OPPh₂py-O,N)], [Re^IVCl₄(OPPh₂py-O,N) and [Re^IVCl₃(OH)(OPPh₂py-O,N)] have been isolated. Reduction of the metal center occurs using an excess of PPh₂py and heating of the reaction mixtures under reflux. The products have been characterised spectroscopically and by X-ray structure analysis. Monodentate co-ordination via phosphorus has been found for the rhenium(I) carbonyl complexes and [Tc^VNCl₂(PPh₂py-P)₂]. In the latter compound a trigonal-bipyramidal coordination sphere is formed with the phosphines as axial ligands (bond angle P-Tc-P: 161.69(3)°). The chelated complexes show small N-Re-P and N-Re-O bite angles of 63.6° and 77.7-82.2° due to the four-membered or five-membered chelate rings. The pyridine nitrogen occupies the axial position (trans to O^2- ) in [ReOCl₃(PPh₂py-P,N)] whereas equatorial co-ordination is found in [ReOCl₃(OPPh₂py-O,N)]. Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(99)00216-8

Polyhedron 18 (1999) 2995–3003
www.elsevier.nl/locate/poly
Rhenium and technetium complexes with diphenyl(2-pyridyl)phosphine
b
c
c
d
Ulrich Abrama , , Roger Alberto , Jonathan R. Dilworth , Yifan Zheng , Kirstin Ortner
*
aForschungszentrum Rossendorf, Institute of Radiochemistry, c/o Dresden University of Technology, Institute of Analytical Chemistry, D-01062
Dresden, Germany
bPaul-Scherrer-Institute, Division of Radiopharmacy, CH-5232 Villigen, Switzerland
cInorganic Chemistry Laboratories, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
d
¨
¨
University of Tubingen, Institute of Inorganic Chemistry, Auf der Morgenstelle 18, D-72076 Tubingen, Germany
Received 17 May 1999; accepted 19 July 1999
Abstract
The potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh2py) reacted with (NEt4)2[MIX3(CO)3] complexes (M5Re, Tc;
X5Cl, Br) to give (NEt4)[MIX2(CO)3(PPh2py-P)] or [MIX(CO)3(PPh2py-P)2] depending on the amount of the ligand used. The reaction
with (NBu4)[TcVINCl4] yielded [TcVNCl2(PPh2py-P)2] whereas from the reaction with (NBu4)[ReOCl4] the complexes
[ReVOCl3(PPh2py-P,N)], [ReVOCl3(OPPh2py-O,N)], [ReIVCl4(OPPh2py-O,N) and [ReIVCl3(OH)(OPPh2py-O,N)] have been isolated.
Reduction of the metal center occurs using an excess of PPh2py and heating of the reaction mixtures under reflux. The products have been
characterised spectroscopically and by X-ray structure analysis. Monodentate co-ordination via phosphorus has been found for the
rhenium(I) carbonyl complexes and [TcVNCl2(PPh2py-P)2]. In the latter compound a trigonal-bipyramidal coordination sphere is formed
with the phosphines as axial ligands (bond angle P–Tc–P: 161.69(3)8). The chelated complexes show small N–Re–P and N–Re–O bite
angles of 63.68 and 77.7–82.28 due to the four-membered or five-membered chelate rings. The pyridine nitrogen occupies the axial
position (trans to ‘‘O22’’) in [ReOCl3(PPh2py-P,N)] whereas equatorial co-ordination is found in [ReOCl3(OPPh2py-O,N)].
1999
Elsevier Science Ltd. All rights reserved.
Keywords: Rhenium; Technetium; Diphenylpyridylphosphine; Diphenylpyridylphosphine oxide; X-ray structures
1. Introduction
which can co-ordinate as a monodentate or chelating
ligand depending on the requirements of the metal center
[5–10]. Technetium complexes with this ligand have not
yet been reported. The very few rhenium complexes with
PPh2py all contain the pyridyl phosphine as bridging
ligand between two quadrupole bonded Re–Re units [11–
13]. The co-ordination of diphenyl(2-pyridyl)phosphine
oxide, OPPh2py (II), has been observed e.g. at Pt(IV) [10]
or U(VI) centers [14]. In the latter case the formation of
pyridine N-oxide was found to give overall O,O-co-ordina-
tion with the actinide element.
Technetium and rhenium co-ordination chemistry is of
particular interest due to the favourable nuclear properties
of 99mTc (Eg5140 keV, half-life t1 / 256.02 h) which makes
this isotope the workhorse for diagnostic nuclear medicine
[1]. The b-emitting rhenium nuclides 186Re and188Re are
under investigation for possible applications in radioim-
munotherapy [2,3]. Fundamental chemical studies are
possible with the naturally occurring non-radioactive
rhenium (185Re: 37.07%, 187Re: 62.93% abundance) or the
long-lived technetium isotope 99Tc (weak b2-emitter,
E
max50.3 MeV, t1 / 252.123105 (a) which allow conven-
tional laboratory techniques (provided some elemental
radiation protection regulations [4] are regarded in the case
of technetium).
Diphenyl(2-pyridyl)phosphine (I) is a versatile ligand
*Corresponding author. Tel.: 149-351-463-2508; fax: 149-351-463-
7188.
E-mail address: abram@fz-rossendorf.de (U. Abram)
In the present paper we report the complex formation of
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00216-8
1999 Elsevier Science Ltd. All rights reserved.

2996
U. Abram et al. / Polyhedron 18 (1999) 2995–3003
PPh2py (and OPPh2py) with mononuclear rhenium and
technetium complexes with the metal in different oxidation
states and with different co-ligands.
2. Results and discussion
The reaction pattern of PPh2py with rhenium or tech-
netium and the structure of the products are strongly
dependent on both the core and the oxidation state of the
transition metals in the precursors and the reaction con-
ditions.
Coordination only via phosphorus is observed when the
rhenium(I) or technetium(I) fac-tricarbonyl complexes
[MX3(CO)3]2- (M5Re, Tc; X5Cl, Br) are reacted with
the pyridylphosphine. Complexes of the stoichiometries
[MX2(CO)3(PPh2py-P)]2 or [MX(CO)3(PPh2py-P)2]
(M5Tc, X5Cl; M5Re, X5Br) are obtained depending
on the [MX3(CO)3]2– /ligand ratio. The anionic, mono-
substituted complexes are formed in almost quantitative
yields when equivalent amounts of the starting materials
are heated under reflux in methanol. Long, pale-yellow
needles crystallize directly from the reaction mixture upon
cooling. Well-resolved facial tricarbonyl patterns in the IR
spectra confirm the retention of the fac-[M(CO)3]1 core.
The [MX2(CO)3(PPh2py-P)]2 complex anions crystallize
with NEt14 as counter-ions. Using an excess of PPh2py, the
neutral [MX(CO)3(PPh2py-P)2] complexes are formed.
Substitution of the remaining X2 by a third PPh2py ligand
failed even when a large excess was used. This is mainly
due to the steric requirements of the bulky PPh2py ligand
and has been observed previously for PPh3 complexes with
the [Re(CO)3]1 core [15].
X-ray structure analyses have been performed for
(NEt4)[ReBr2(CO)3(PPh2py-P)] and [ReBr(CO)3(PPh2py-
P)2] verifying the triphenylphosphine-like co-ordination of
the ligands. Fig. 1 and Fig. 2 show ZORTEP representa-
tions of the complex molecules. Selected bond lengths and
angles are summarized in Tables 1 and 2. The Re–Br and
Re–P bond lengths are comparatively long which can be
explained with the strong structural trans influence due to
the facial CO ligands. Whereas the co-ordination octahed-
ron in [ReBr2(CO)3(PPh2py-P)]2 is only slightly distorted
by the bulky PPh2py ligand, a significant repulsion of the
two phosphine ligands can be observed in
Fig. 1. ZORTEP representation [16] of the complex anion in
(NEt4)[ReBr2(CO)3(PPh2py-P)]. Thermal ellipsoids represent 30% prob-
ability. H atoms have been omitted for clarity.
Starting from (NEt4)2[TcCl3(CO)3] and PPh2py the analo-
gous complexes (NEt4)[TcCl2(CO)3(PPh2py-P)] and
[TcCl(CO)3(PPh2py-P)2] have been isolated and spectros-
copically characterized. The similarity between tech-
netium(I) and rhenium(I) is mainly due to the fact that no
redox processes are involved in the ligand exchange
reactions studied. For the higher formal oxidation states
redox reactions prevail, and there are distinct differences in
the chemistry of the two elements. Thus the reaction of
[TcVINCl4]2 with PPh2py gives the Tc(V) complex
[TcNCl2(PPh2py-P)2] in good yields. No further reduction
of the metal has been observed. From the analogous
reaction with [ReVINCl4]2 only dark-coloured solutions
could be obtained from which we could not isolate defined
crystalline products.
[TcNCl2(PPh2py-P)2] is a yellow-brown solid which is
only slightly soluble in most organic solvents. The IR
spectrum of the compound shows the n(Tc;N) vibration
at 1072 cm21. This value is similar to that observed
previously for [TcNCl2(Ph3P)2]. An X-ray structure analy-
sis shows that [TcNCl2(PPh2py-P)2] is isotypic with this
complex [17]. Fig. 3 illustrates the trigonal-bipyramidal
structure of the complex with the PPh2py ligands in axial
positions. Selected bond lengths and angles are summa-
rized in Table 3. The trigonal bipyramid is fairly distorted
with equatorial angles between 109.79(2)8 and 140.42(4)8
and a P–Tc–P angle of 161.69(3)8. The Tc;N bond
[ReBr(CO)3(PPh2py-P)2]
(P(1)–Re–P(2)
angle:
100.97(6)8). This may explain that the introduction of a
third PPh2py ligand is unfavourable and the corresponding
tris-complex could not be obtained even with a large
excess of PPh2py. The nitrogen sites in the aromatic rings
are ordered and could unambiguously be derived from the
Fourier maps by inspection of the thermal parameters of
the ring atoms.
˚
length of 1.594(3) A is one of the shortest technetium–
nitrogen bonds observed [18]. The positions of the
pyridine nitrogen atoms were derived from the Fourier
maps and confirmed by refinement. [TcNCl2(PPh2py-P)2]
and [TcNCl2(Ph3P)2] are also very similar in their chemi-
cal behaviour and both compounds represent useful start-
For the tricarbonyl complexes studied no significant
differences are observed between rhenium and technetium.

U. Abram et al. / Polyhedron 18 (1999) 2995–3003
2997
Fig. 2. ZORTEP representation [16] of [ReBr(CO)3(PPh2py-P)2]. Thermal ellipsoids represent 30% probability. H atoms have been omitted for clarity.
Table 1
various compositions. During our studies we isolated and
˚
Selected bond lengths [A] and angles [8] in (NEt4)[ReBr2(CO)3(PPh2py-
characterized [ReOCl3(PPh2py-P,N)], [ReOCl3(OPPh2py-
O,N)], [ReCl3(OH)(OPPh2py-O,N)] and ReCl4(OPPh2py-
O,N)]. In all cases bidentate bonding of the phos-
phinopyridine or its oxidation product was observed. No
evidence was found for the formation of complexes with
monodentate phosphine ligands analogous to the tri-
phenylphosphine compounds [ReOCl3(PPh3)2] [19,20] or
[ReOCl2(OR)(PPh3)2] [21]. The reduction of rhenium(V)
by PPh2py is predominant and can already be observed
when equimolar amounts of (NBu4)[ReOCl4] and PPh2py
are used and the reaction is performed at room-temperature
in acetone in air. Long green needles of
[ReOCl3(OPPh2py-O,N)] crystallize from such reaction
mixtures upon cooling. A second product can be obtained
upon concentrating of the mother liquor in a stream of
nitrogen. [ReOCl3(PPh2py-P,N)] (co-crystallized with
(NBu4)2[ReCl6]) deposits in form of large green blocks
and can easily be separated from the needles of the
phosphine oxide complex.
P)]a
Re–C(1)
Re–C(3)
Re–Br(2)
1.921(7)
1.94(2)
2.617(1)
Re–C(2)
Re–Br(1)
Re–P(1)
1.928(7)
2.645(1)
2.503(1)
P(1)–Re–Br(1)
P(1)–Re–C(2)
Br(1)–Re–Br(2)
Br(2)–Re–C(3)
95.31(4)
95.4(2)
89.87(3)
91.9(1)
P(1)–Re–Br(2)
P(1)–Re–C(3)
Br(1)–Re–C(3)
89.24(4)
88.3(8)
84.3(2)
a A disorder of 15% between Br(1) and the carbonyl group C(3), O(3)
has been taken into account during the refinement.
ing points for the synthesis of further technetium nitrido
complexes [18].
Whereas the reaction of PPh2py with (NBu4)[TcOCl4]
results in dark coloured solutions from which no crys-
talline products could be obtained, that with
(NBu4)[ReOCl4] gives Re(V) or Re(IV) complexes of
[ReOCl3(PPh2py-P,N)]
co-crystallizes
with
Table 2
a
˚
Selected bond lengths [A] and angles [8] in [ReBr(CO)3(PPh2py-P)2]
(NBu4)2[ReCl6] in the tetragonal space group P42 /n with
disordered [ReCl6]22 anions around the symmetry centre
Re–C(1)
Re–C(3)
Re–P(1)
1.956(9)
2.033(7)
2.514(2)
Re–C(2)
Re–Br(1)
Re–P(2)
1.957(9)
2.606(1)
2.510(2)
1
4
1
4
1
4
] ] ]
at
,
,
giving an overall composition of the crystals of
1
]
[ReOCl3(PPh2py-P,N)]?4 (NBu4)2[ReCl6] which perfectly
fits with the analytical results obtained. Fig. 4 shows an
ellipsoid representation [16] of the [ReOCl3(PPh2py-P,N)]
molecule. Selected bond lengths and angles are summa-
rized in Table 4. The co-ordination sphere of rhenium
clearly shows deviations from an ideal octahedron. They
can be ascribed to the restricted bite angle of the four-
membered chelate ring and the steric requirements of the
P(1)–Re–Br(1)
P(1)–Re–C(2)
P(2)–Re–Br(1)
P(2)–Re–C(3)
Br(1)–Re–C(2)
93.27(5)
85.0(2)
85.72(5)
94.5(5)
86.8(3)
P(1)–Re–P(2)
P(1)–Re–C(3)
P(2)–Re–C(1)
Br(1)–Re–C(1)
100.97(6)
87.5(4)
85.5(3)
90.5(3)
a A disorder of 15% between Br(1) and the carbonyl group C(3), O(3)
has been taken into account during the refinement.

2998
U. Abram et al. / Polyhedron 18 (1999) 2995–3003
Fig. 3. ZORTEP representation [16] of [TcNCl2(PPh2py-P)2] with 30% thermal ellipsoids. H atoms have been omitted for clarity.
multiply bonded oxo ligand which leads to O(10)–Re(1)–
Cl angles between 96.9 and 115.28. The fourth equatorial
position is occupied by phosphorus directing the pyridine
donor site to the axial position trans to ‘‘O22’’. The Re–N
position reflecting better donor capabilities of the nitrogen
atom. Consequently, the Re–N(12) and Re–N(42) bonds
are shorter than the Re–N(12) bond in [ReOCl3(PPh2py-
P,N)]. Also the distortions of the octahedral co-ordination
sphere of the metal is less than in the phosphine complex.
This is obvious by O(10)–Re–Cl angles between 95.2 and
103.78. The bonds to the oxygen atoms trans to the oxo
˚
bond of 2.280(7) A is comparatively long which can be
attributed to the strong trans influence of the oxo ligand. In
a side reaction PPh2py is oxidized even at room-tempera-
ture to yield OPPh2py and [ReCl6]22. The diphenyl-
pyridyl-phosphine oxide formed reacts preferentially with
[ReOCl4]2 to give [ReOCl3(OPPh2py-O,N)]. No Re(IV)
complexes containing PPh2py could be isolated from the
1:1 reaction.
[ReOCl3(OPPh2py-O,N)] crystallises in the monoclinic
space group P21 /c with two molecules per asymmetric
unit. Fig. 5 shows the molecular structure of one of the two
symmetrically independent individuals. Selected bond
lengths and angles are compared with the corresponding
values in [ReOCl3(PPh2py-P,N)] in Table 4. In contrast to
the latter complex the pyridine donor site in
[ReOCl3(OPPh2py-O,N)] is co-ordinated in equatorial
Table 3
˚
Selected bond lengths [A] and angles [8] in [TcNCl2(PPh2py-P)2]
Tc–N(1)
Tc–P
1.594(3)
2.462(1)
Tc–Cl
2.376(1)
N(1)–Tc–P
Cl–Tc–Cla
Cl–Tc–P
99.16(2)
140.42(4)
87.84(4)
N(1)–Tc–Cl
P–Tc–P9
P–Tc–Cl(1)9
109.79(2)
161.69(3)
85.98(3)
a Symmetry operations to generate equivalent positions: 1 2 x, y, 1.5 2
Fig. 4. Molecular structure [16] of [ReOCl3(PPh2py-P,N)] with 50%
thermal ellipsoids. H atoms have been omitted for clarity.
z.

U. Abram et al. / Polyhedron 18 (1999) 2995–3003
2999
rhenium(IV) compounds as indicated by 31P-NMR spec-
troscopy of the reaction mixture.
Table 4
˚
Selected bond lengths [A] and angles [8] in [ReOCl3(PPh2py-P,N)] and
[ReOCl3(OPPh2py-O,N)]a
The molecular structures of [ReCl4(OPPh2py-O,N)] and
[ReCl3(OH)(PPh2py-O,N)] are shown in Fig. 6. Selected
bond lengths are contained in Table 5. It is evident that
neither donor site of the chelating ligand in
[ReCl4(OPPh2py-O,N)] cause a significant structural trans
[ReOCl3(PPh2py-P,N)]
[ReOCl3(OPPh2py-O,N)]a)
Re–O(10)
Re–Cl(1)
Re–Cl(2)
Re–Cl(3)
Re–N(12)
Re–O(1)
Re–P
1.678(6)
2.351(2)
2.370(2)
2.335(2)
2.280(7)
–
1.671(5)
2.374(2)
2.313(2)
2.368(2)
2.169(6)
2.090(5)
–
influence. The longest Re–Cl bonds (2.303(2) and
2
˚
2.339(2) A) are observed trans to Cl . Distortions from an
2.423(2)
ideal octahedral co-ordination sphere are mainly due to the
small bite angle of OPPh2py, which is 82.2(2)8 in the
present case. A similar bonding situation is observed in
[ReCl3(OH)(OPPh2py-O,N)]. The hydroxo ligand is
situated trans to the phosphine oxide group which exerts
little trans labilisation. This suggests that the formation of
[ReCl3(OH)(OPPh2py-O,N)] is a result of the protonation
of [ReOCl(OPPh2py-O,N)] rather than from a ligand
exchange starting from the rhenium(IV) complex
[ReCl4(OPPh2py-O,N)]. Further reduction of the metal to
rhenium(III) is not observed under any of the reaction
conditions used.
O(10)–Re–O(1)
O(10)–Re–P
–
167.0(2)
–
93.6(3)
O(10)–Re–Cl(1) 98.9(2)
O(10)–Re–Cl(2) 96.9(2)
O(10)–Re–Cl(3) 115.2(3)
O(10)–Re–N(12) 156.5(3)
95.2(2)
103.7(2)
97.1(2)
89.0(3)
123.3(3)
–
Re–O(1)–P(1)
Re–P–C(11)
–
87.3(3)
O(1)–P(1)–C(11)–
C(11)–N(12)–Re 105.3(5)
103.2(3)
121.9(5)
a Values for one symmetry-independent molecule.
Studies dealing with the co-ordination chemistry of
rhenium with other ligand systems having more than one
pyridine and/or NH2 substituents are in progress in our
laboratories.
˚
ligands (2.090(5) and 2.174(6) A, respectively) are only
slightly longer than the Re–O bonds in a series of Re(II)
triphenylphosphine oxide complexes where OPPh3 is
situated trans to NO, Cl or OPR3 [22].
Rhenium(IV) complexes of the OPPh2py ligand can be
isolated when an excess of PPh2py is used for the reaction
with (NBu4)[ReOCl4]. Large green columnar crystals are
isolated directly from the reaction mixture. The crystals
3. Experimental
(NEt4)2[ReBr3(CO)3] [23], (NEt4)2[TcCl3(CO)3] [24],
(NBu4)[ReOCl4] [24] and (NBu4)[TcNCl4] [25] were
prepared by literature procedures. PPh2py was purchased
from ALDRICH and used without further purification. IR
spectra were recorded on a Perkin-Elmer Spectrum 1000
spectrometer. NMR spectra were measured on a VARIAN
Gemini 2000 instrument (300 MHz) with TMS as internal
standard. FAB mass spectra were obtained using a TSQ 70
(FINNIGAN MAT) spectrometer with nitrobenzylalcohol
as matrix (8 keV, xenon).
contain
[ReCl4(OPPh2py-O,N)]
and
[ReCl3(OH)(OPPh2py-O,N)] in a 1:1 ratio. The latter
compound has obviously been formed by partial hydrolysis
and its formation is supressed when the reaction is
performed in carefully dried solvents. Any rhenium(V)
complexes which are formed immediately after the addi-
tion of PPh2py are rapidly reduced to the paramagnetic
3.1. (NEt4 )[ReBr2(CO)3(PPh2 py-P)]
(NEt4)2[ReBr3(CO)3] (77 mg, 0.1 mmol) was dissolved
in about 10 ml MeOH, mixed with a solution of PPh2py
(26 mg, 0.1 mmol) in 5 ml MeOH and heated under reflux
for 30 min. The solvent was removed under vacuum and
the oily residue was extracted with THF. The extracts were
evaporated to dryness and the obtained colourless solid
was redissolved in about 1 ml of CH2Cl2 and layered with
n-hexane. Long needles deposited upon diffusion of hex-
ane into the dichloromethane solution. Yield: 62 mg
(75%). Found: C, 40.0; H, 3.8; N, 3.5%. Calc. for
C28H34N2Br2O3PRe: C, 40.8; H, 4.1; N, 3.4%. IR (nmax
/
Fig. 5. Ellipsoid representation [16] of [ReOCl3(OPPh2py-O,N)] with
50% thermal ellipsoids. H atoms have been omitted for clarity.
cm21): 1861, 1913, 2010 vs. (CO). FAB2 MS: m/z 614

3000
U. Abram et al. / Polyhedron 18 (1999) 2995–3003
Fig. 6. Ellipsoid representation [16] of [ReCl4(OPPh2py-O,N)] and [ReCl3(OH)(PPh2py-O,N)] with 30% thermal ellipsoids. H atoms have been omitted
for clarity.
(15%,
[ReBr(CO)3(PPh2py)]2),
534
(100%,
in about 10 ml MeOH, mixed with a solution of PPh2py
(130 mg, 0.5 mmol) in 5 ml MeOH and heated under
reflux for 30 min. The solvent was removed in vacuum and
the oily residue was extracted with THF. The extracts were
brought to dryness and the obtained colourless solid was
redissolved in about 1 ml of CH2Cl2 and overlayered with
n-hexane. Colourless blocks deposited upon diffusion of
hexane into the dichloromethane solution. Yield: 79 mg
(90%). Found: C, 49.3; H, 3.0; N, 3.2%. Calc. for
[Re(CO)3(PPh2py)]2).
3.2. [ReBr(CO)3(PPh2 py-P)2 ]
(NEt4)2[ReBr3(CO)3] (77 mg, 0.1 mmol) was dissolved
Table 5
˚
Selected bond lengths [A] and angles [8] in [ReCl4(OPPh2py-O,N)] and
[ReCl3(OH)(OPPh2py-O,N)]
C37H28N2BrO3P2Re: C, 50.6; H, 3.2; N, 3.2%. IR (nmax
/
cm21): 1906, 1944, 2027 vs. (CO). FAB1 MS: m/z 797
[ReCl4(PPh2py-P,N)]
[ReCl3(OH)(PPh2py-O,N)]
2.303(2) Re(2)–Cl(11)
2.339(2) Re(2)–Cl(12)
2.339(2) Re(2)–Cl(13)
2.247(3) Re(2)–O(14)
2.177(7) Re(2)–N(32)
2.040(6) Re(2)–O(2)
1.521(6) O(2)–P(2)
(78%,
[Re(CO)3(PPh2py)2]1),
769
(45%,
Re(1)–Cl(1)
Re(1)–Cl(2)
Re(1)–Cl(3)
Re(1)–Cl(4)
Re(1)–N(2)
Re(1)–O(1)
O(1)–P(1)
2.308(4)
2.375(4)
2.354(4)
2.002(7)
2.188(9)
2.126(9)
1.509(7)
[Re(CO)2(PPh2py)2]1), 534 (55%, [Re(CO)3(PPh2py)]1).
3.3. (NEt4 )[TcCl2(CO)3(PPh2 py-P)]
This compound was prepared according to the procedure
described for the analogous rhenium complex starting from
equivalent amounts of (NEt4)2[TcCl3(CO)3] and PPh2py.
Colourless needles, yield 65%. Found: C, 53.1; H, 4.8; N,
3.9%. Calc. for C28H34N2Cl2O3PTc: C, 51.9; H, 5.3; N,
4.3%. IR (nmax /cm21): 1857, 1905, 2015 vs. (CO).
Cl(1)–Re(1)–N(2)
Cl(1)–Re(1)–O(1)
Cl(1)–Re(1)–Cl(2)
Cl(1)–Re(1)–Cl(3)
Cl(1)–Re(1)–Cl(4)
Cl(2)–Re(1)–N(2)
Cl(2)–Re(1)–O(1)
173.1(2)
Cl(11)–Re(2)–N(32)
169.2(3)
90.9(2)
92.83(9)
93.04(9)
93.4(1)
86.7(2)
89.0(2)
Cl(11)–Re(2)–O(2)
Cl(11)–Re(2)–Cl(12)
Cl(11)–Re(2)–Cl(13)
Cl(11)–Re(2)–O(14)
Cl(12)–Re(2)–N(32)
Cl(12)–Re(2)–O(2)
90.1(2)
90.0(1)
92.0(2)
99.3(3)
87.7(3)
84.4(3)
Cl(2)–Re(1)–Cl(3) 173.03(8)
Cl(12)–Re(2)–Cl(13) 167.8(3)
3.4. [TcCl(CO)3(PPh2 py-P)2 ]
Cl(2)–Re(1)–Cl(4)
Cl(3)–Re(1)–N(2)
Cl(3)–Re(1)–O(1)
Cl(3)–Re(1)–Cl(4)
Cl(4)–Re(1)–N(2)
Cl(4)–Re(1)–O(1)
91.1(1)
87.0(2)
87.2(2)
92.3(1)
93.4(2)
175.7(2)
Cl(12)–Re(2)–O(14)
Cl(13)–Re(2)–N(32)
Cl(13)–Re(2)–O(2)
Cl(13)–Re(2)–O(14)
O(14)–Re(2)–N(32)
O(14)–Re(2)–O(2)
95.2(2)
88.1(2)
83.6(2)
96.3(2)
91.4(3)
170.5(3)
The complex has been prepared similarly to the rhenium
analogue starting from (NEt4)2[TcCl3(CO)3] and PPh2py
(ratio 1:5). Colourless blocks, yield: 65%. Found: C, 58.8;
H, 4.1; N, 3.8%. Calc. for C37H28N2ClP2Tc: C, 59.6; H,
3.8; N, 3.8%. IR(nmax /cm21): 1908 1966, 2017 s (CO).
O(1)–Re(1)–N(2)
Re(1)–N(2)–C(1)
N(2)–C(1)–P(1)
C(1)–P(1)–O(1)
Re(1)–O(1)–P(1)
82.2(2)
117.7(5)
113.3(6)
105.4(4)
121.2(4)
O(2)–Re(2)–N(32)
Re(2)–N(32)–C(31)
N(32)–C(31)–P(2)
C(31)–P(2)–O(2)
Re(2)–O(2)–P(2)
79.1(3)
120.5(5)
112.8(6)
105.2(4)
121.2(4)
3.5. [TcNCl2(PPh2 py-P)2 ]
(NBu4)[TcNCl4] (0.1 mmol, 50 mg) was dissolved in

Table 6
X-ray structure data collection and refinement parameters
(NEt4)[ReBr2(CO)3- [ReBr(CO)3(PPh2py-P)2] [TcNCl2(PPh2py-P)2] [ReOCl3(PPh2py-P,N)2]? [ReOCl3(OPPh2py-O,N)] [ReCl4(OPPh2py-O,N)]?
1
]
(PPh2py-P)]
4 (NBu4)2[ReCl6]
[ReCl3(OH)(OPPh2py-O,N)]
Crystal dimensions (mm)
Formula
0.4030.1530.15
C28H34Br2N2O3PRe C37H28BrN2O3P2Re
823.56
0.4030.4030.30
0.5030.253.20
C34H28Cl2N3P2Tc
709.43
0.4030.3030.30
C25H32Cl4.5N1.5OPRe1.25 C17H14Cl3NO2PRe
792.77
0.2530.1030.10
0.5030.1030.10
C34H29Cl7N2O3P2Re2
1196.08
M (g mol21
)
876.66
587.81
.
Measuring Device
Radiation/l (A)
Crystal system
Space group
Unit cell
CAD4
DIP2000
CAD4
CAD4
CAD4
CAD4
Mo Ka/0.71073
Monoclinic
P21 /c
a513.654(1) A
b516.126(2) A
c517.397(2) A
b595.07(1)8
3815.6(7)
4
˚
Cu Ka/1.54184
Monoclinic
P21 /c
a59.390(1) A
b518.961(2) A
Mo Ka/0.71073
Monoclinic
P21 /c
a59.280(2) A
b538.515(7) A
c59.836(2) A
b5108.33(3)8
3337(1)
4
1.745
265
Mo Ka/0.71073
Monoclinic
C2/c
a524.061(7) A
b59.344(1) A
c515.698(5) A
b5116.11(2)8
3169(1)
4
1.487
18
Mo Ka/0.71073
Tetragonal
P42 /n
a517.665(1) A
b517.665(1) A
Cu Ka/1.54184
Monoclinic
P21 /c
a513.757(1) A
b516.082(1) A
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
c517.106(2) A
c518.640(1) A
c517.396(1) A
b596.67(1)8
3025.0(6)
4
1.808
18
b5908
5816,7(6)
8
1.811
18
b594.95(1)8
3834.3(4)
8
2.037
18
3
˚
V (A )
Z
1
Dc (g cm23
T (8C)
)
2.082
265
1
Scan type
v scans
11.699
c scans
0.5703
0.9459
5749
4724
4425
344
v scans
0.753
c scans
0.8992
0.9569
3565
3436
2862
247
0.0330/0.0782
1.060
v scans
5.702
c scans
0.8121
0.9650
5455
5105
4155
328
v scans
17.133
c scans
0.837
0.9586
7386
6499
4588
451
v scans
6.952
DIFABS [30]
0.229
1.000
5743
5230
4676
456
0.0422/0.0964
1.107
Linear absorption coefficient, m (mm21
Absorption correction
Tmin
)
4.974
None
2
300
Tmax
Measured reflections
Independent reflections
Independent reflections (I . 2s(I))
Refined parameters
R1 (F)/wR2 (F2)
GooF
4907
4907
4501
425
0.0406/0.0976
1.185
0.0402/0.1040
1.061
0.0528/0.1178
1.146
0.0384/0.0847
1.009

3002
U. Abram et al. / Polyhedron 18 (1999) 2995–3003
10 ml acetone and PPh2py (0.5 mmol, 130 mg) was added
in 10 ml acetone. The mixture was heated under reflux for
2 h and reduced in volume to about 5 ml. Upon cooling
yellow-brown crystals of [TcNCl2(PPh2py-P)2] deposited
on the flask walls. Yield: 32 mg (45%). Found: C, 57.4; H,
3.8; N, 7.3%. Calc. for C34H28N3Cl2P2Tc: C, 57.5; H, 3.9;
N, 7.3%. IR (nmax /cm21): 1072 s (Tc;N).
hydrogen atoms. Refinement was performed using
SHELXL97 [29]. Hydrogen atoms have been included at
calculated positions and regarded using the ‘riding model’
option of SHELXL97. Certain disorders have been taken
into
account
during
the
refinement
of
(NEt4)[ReBr2(CO)3(PPh2py-P)] (a pair of trans situated
Br2 /CO ligands), [ReBr(CO)3(PPh2py-P)2] (a pair of
trans situated Br2 /CO ligands), [ReOCl3(PPh2py-P,N)]?
(NBu4)2[ReCl6] (disordered ReCl262 anion) and
1
4
]
3.6. [ReOCl3(OPPh2 py-O,N)] and [ReOCl3(PPh2 py-
1
[ReCl4(OPPh2py-O,N)]?[ReCl3(OH)(OPPh2py-O,N)] (Re
atom in the hydroxo compound). Crystal data and more
details of the data collections and refinements are con-
tained in Table 6.
]
P,N)]? 4 (NBu4 )2 [ReCl6 ]
(NBu4)[ReOCl4] (59 mg, 0.1 mmol) was dissolved in
about 5 ml acetone and PPh2py (26 mg, 0.1 mmol) in 5 ml
acetone was added. The mixture was stirred for 5 h at
room temperature and reduced in volume to about 5 ml.
Long green needles of [ReOCl3(OPPh2py-O,N)] deposited
upon keeping overnight in a refrigerator. The crystals were
removed by filtration and dried in vacuum. Yield: 18 mg
(30% based on Re). Found: C, 35.4; H, 2.8; N, 1.9; Cl,
18.5%. Calc. for C17H14NCl3O2PRe: C, 34.7; H, 2.4; N,
2.4; Cl, 18.1%. IR (nmax /cm21): 989 s (Re5O), 1101 s
(P5O). FAB1 MS: m/z 589 (5%, [M1H]1), 536 (52%,
[ReOCl2(PPh2py)]1).
Supplementary data
Supplementary data are available from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK on request, quoting the deposition number:
((Et4N)[ReBr2(CO)3(PPh2py-P)]
[ReBr(CO)3(PPh2py-P)2]
[ReOCl3(PPh2py-P,N)]
CCDC
CCDC
CCDC
(NBu4)[ReCl6]
118881,
118882,
118883,
CCDC
1
Xylene (2 ml) was added to the filtrate of the above
mentioned reaction mixture and the volume of the solution
]
[ReOCl3(OPPh2py-N,O)]?4
118884, [ReCl4(OPPh2py-N,O)]?[Re(OH)Cl3(OPPh2py-
N,O)] CCDC 118885, [TcNCl2(PPh2py-P)2] CCDC
118886.
was reduced by a slow stream of nitrogen. Large, dark
1
]
green blocks of [ReOCl3(PPh2py-P,N)]?4 (NBu4)[ReCl6]
deposited with a small amount of thin needles identified as
[ReOCl3(OPPh2py-O,N)] and removed by hand). Yield: 32
mg (40% based on Re). Found: C, 38.3; H, 3.5; N, 2.2; Cl,
18.7%. Calc. for C100H128N6Cl18O4P4Re5: C, 37.8; H, 4.0;
N, 2.6; Cl, 20.1%. IR (nmax /cm21): 956s (Re5O).
Acknowledgements
We thank the Herrmann-Starck AG for generously
providing rhenium metal and gratefully acknowledge
financial support from the DAAD and the British Council
under the ARC programme. UA additionally thanks the
3.7. [ReCl4(OPPh2 py-O,N)]?[ReCl3(OH)(OPPh2 py-O,N)]
(NBu4)[ReOCl4] (59 mg, 0.1 mmol) was dissolved in
about 5 ml acetone and PPh2py (130 mg, 0.5 mmol) in 10
ml acetone was added. The mixture was heated under
reflux for 5 h and reduced in volume to about 5 ml. Xylene
(2 ml) was added and the reaction mixture was kept in a
refrigerator for several days giving bright green columnar
crystals. Yield: 36 mg (60% based on Re). Found: C, 34.8;
H, 2.1; N, 2.8; Cl, 19.9%. Calc. for C34H29N2Cl7O3P2Re2:
C, 34.1; H, 2.4; N, 2.4; Cl, 20.8%. IR (nmax /cm21): 2871 s
(OH, H bonded to Cl(11)).
¨
Fonds der Chemischen Industrie and Professor J. Strahle
¨
(Tubingen).
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