Synthesis and reactivity of germyl complexes of manganese and rhenium

Article abstract of DOI:10.1016/j.jorganchem.2011.09.014

Trichlorogermyl complexes M(GeCl₃)(CO)_nP _{5- n} (1-4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)₂ (a), P(OEt)₃ (b)] were prepared by allowing chloro compounds MCl(CO) _nP_{5- n} to react with an excess of GeCl₂? dioxane in 1,2-dichloroethane. Treatment of compounds 1-4 with LiAlH₄ in thf yielded trihydridegermyl derivatives M(GeH₃)(CO) _nP_5-n (5-8), whereas treatment of the same complexes with NaBH₄ in ethanol afforded triethoxygermyl derivatives M[Ge(OEt) ₃](CO)_nP_5-n (9-11). Trimethylgermyl compounds M(GeMe₃)(CO)_nP_5-n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)₃](CO)₃[PPh(OEt) ₂]₂ (14a) were also prepared by allowing trichlorogermyl compounds 1-4 to react with either MgBrMe or Li⁺CCPh^-, respectively, in thf. Treatment of compound Re(GeCl₃)(CO) ₃[PPh(OEt)₂]₂ (4a) with SnCl ₂?2H₂O gave the stannyl-germyl derivative Re[GeCl₂(SnCl₃)](CO)₃[PPh(OEt) ₂]₂ (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.

Full text of DOI:10.1016/j.jorganchem.2011.09.014

Journal of Organometallic Chemistry 696 (2012) 4191e4201
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and reactivity of germyl complexes of manganese and rhenium
,
a
b
Gabriele Albertin a , Stefano Antoniutti , Jesús Castro
*
a Dipartimento di Scienze Molecolari e Nanosistemi, 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
a r t i c l e i n f o
a b s t r a c t
Article history:
Trichlorogermyl complexes M(GeCl3)(CO)nP5ꢀ n (1e4) [M ¼ Mn, Re; n ¼ 2, 3; P ¼ PPh(OEt)2 (a), P(OEt)3
Received 20 May 2011
Received in revised form
7 September 2011
(b)] were prepared by allowing chloro compounds MCl(CO)nP5ꢀ
to react with an excess of
n
GeCl2ꢁdioxane in 1,2-dichloroethane. Treatment of compounds 1e4 with LiAlH4 in thf yielded trihy-
dridegermyl derivatives M(GeH3)(CO)nP5ꢀn (5e8), whereas treatment of the same complexes with NaBH4
in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)3](CO)nP5ꢀn (9e11). Trimethylgermyl
compounds M(GeMe3)(CO)nP5ꢀn (12, 13) and the alkynylgermyl derivative Mn[Ge(C^CPh)3](CO)3[P-
Ph(OEt)2]2 (14a) were also prepared by allowing trichlorogermyl compounds 1e4 to react with either
MgBrMe or LiþC^CPhꢀ, respectively, in thf. Treatment of compound Re(GeCl3)(CO)3[PPh(OEt)2]2 (4a)
with SnCl2ꢁ2H2O gave the stannyl-germyl derivative Re[GeCl2(SnCl3)](CO)3[PPh(OEt)2]2 (15a). The
complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and
13a.
Accepted 17 September 2011
Keywords:
Synthesis
Germyl complexes
Phosphite and carbonyl ligands
Manganese
Rhenium
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
organostannyl [M]eSnR3 derivatives of manganese and rhenium of
the type M(SnH3)(CO)nP5ꢀn, M(SnMe3)(CO)nP5ꢀn, M[Sn(C^CPh)3]
The synthesis and reactivity of transition metal complexes
containing trichlorogermyl GeCl3 or triorganogermyl GeR3 groups
as ligands has received considerable attention in recent years [1e3],
both for general interest in the chemistry of complexes containing
bonds to the heavier elements of the 14th group (Si, Ge, Sn) and also
because these complexes are regarded as intermediates in
a number of transition metal-catalysed transformations of group-
14 element compounds [1,4,5]. A number of germyl complexes for
several metals have thus been prepared, mainly by the oxidative
addition of Ge(IV) species [GeCl4, GeH4, GeH4ꢀnRn (n ¼ 1, 2, 3)] to
a transition metal center as a synthetic method [1e3]. The insertion
of GeCl2 into a transition metal chloride bond [3bee] or the thermal
or photochemical substitution of a carbonyl or arene ligand by the
GeCl3 ion [3j,l,m,p] has also been employed to prepare tri-
chlorogermyl [M]eGeCl3 derivatives. However, there are only a few
reports on germyl complexes, especially when compared with the
number of studies on silyl [6] and stannyl [7] derivatives. In addi-
tion, studies on germyl complexes mainly involve metals of the
chrome, iron and nickel triads, whereas the germyl chemistry of Mn
[8] and Re [9] central metals is still relatively unexplored.
(CO)nP5ꢀn, [M{Sn[OC(H)]O]2}(meOH)(CO)2P3]2, M[Sn{C(COOR)]
CH2}3](CO)nP5ꢀn (M ¼ Mn, Re; n ¼ 2, 3; P ¼ phosphites), etc. The
interesting properties shown by these complexes prompted us to
extend study to germyl complexes, with the aim of verifying whether
stable trihydridegermyl and organogermyl derivatives could be
prepared, and howcomparisons between stannyl and germyl species
could be revealed in the manganese triad.
The results of these studies, which include the synthesis and
some reactivity of new germyl complexes of the manganese triad,
and the first example of a trihydridegermyl derivative of rhenium,
are reported here.
2. Experimental section
2.1. General comments
All synthetic work was carried out in an inert atmosphere (Ar,
N2) using standard Schlenk techniques or an inert atmosphere dry-
box. Once isolated, the complexes were found to be relatively stable
in air, but were stored under nitrogen at ꢀ25 ꢂC. All solvents were
dried over appropriate drying agents, degassed on a vacuum line,
and distilled into vacuum-tight storage flasks. Mn2(CO)10 and
Re2(CO)10 were Pressure Chemical Co. (USA) products, used as
received. Phosphonite PPh(OEt)2 was prepared by the method of
Rabinowitz and Pellon [11], while P(OEt)3 was an Aldrich product,
purified by distillation under nitrogen. GeCl2ꢁdioxane, SnCl2ꢁH2O,
We previously reported [10] the synthesis and reactivity of tri-
chlorostannyl [M]eSnCl3, trihydridestannyl [M]eSnH3 and
* Corresponding author. Fax: þ39 041 234 8917.
E-mail address: albertin@unive.it (G. Albertin).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.09.014

4192
G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
and MgBrMe [1.4 mol dmꢀ3 solution in tetrahydrofuran (thf)] were
Aldrich products, used as received. Lithium acetylide LiþC^CPhꢀ
was prepared by reacting a slight excess of phenylacetylene
(36 mmol, 4 mL) with lithium (30 mmol, 0.21 g) in 20 mL of thf.
Other reagents were purchased from commercial sources in the
highest available purity and used as received. Infrared spectra were
recorded on a PerkineElmer Spectrum-One FT-IR spectrophotom-
eter. NMR spectra (1H, 13C, 31P, 119Sn) were obtained on AVANCE 300
Bruker spectrometer at temperatures between ꢀ90 and þ30 ꢂC,
unless otherwise noted.1H and 13C spectra are referred to internal
tetramethylsilane; 31P{1H} chemical shifts are reported with respect
to 85% H3PO4 and 119Sn ones with respect to Sn(CH3)4, and in both
cases downfield shifts are considered positive. COSY, HMQC and
HMBC NMR experiments were performed with standard programs.
The iNMR software package [12] was used to process NMR data. The
conductivity of 10ꢀ3 mol dmꢀ3 solutions of the complexes in
CH3NO2 at 25 ꢂC was measured on a Radiometer CDM 83. Elemental
analyses were determined in the Microanalytical Laboratory of the
Dipartimento di Scienze Farmaceutiche, University of Padova (Italy).
GeCl2ꢁdioxane (3 mmol, 0.7 g), and 20 mL of 1,2-dichloroethane.
The reaction mixture was refluxed for 90 min and then the solvent
was removed under reduced pressure. The oil obtained was tritu-
rated with ethanol (2 mL) until a white solid separated out, which
was filtered and crystallised from CH2Cl2 and ethanol; yield 85%.
3a: IR (KBr pellet) nCO: 2054 (m), 1983, 1969 (s) cmꢀ1
(CD3C6D5, 25 ꢂC)
3.97 m, 3.77 m, and 3.67 m (8H, CH2), 1.19 t and 1.06 t (12H, CH3).
31P{1H} NMR (CD3C6D5, 25 ꢂC)
: A2, 130.0 (s). C23H30Cl3GeO7P2Re
.
1H NMR
d
: 7.67 m and 7.17 me6.97 m (10H, Ph), 4.08 m,
d
(845.63): calcd. C 32.67, H 3.58, Cl 12.58; found C 32.41, H 3.71, Cl
12.42%. 4a: IR (KBr pellet) nCO: 1986,1927 (s) cmꢀ1. 1H NMR (CD2Cl2,
25 ꢂC)
d: 7.86 m, 7.57 m, 7.47 m, and 7.38 m (15H, Ph),
4.03 me3.75 m (12H, CH2), 1.34 t, 1.30 t, and 1.29 t (18H, CH3). 31P
{1H} NMR (CD2Cl2, 25 ꢂC)
d
: AB2, dA 135.4, dB 129.7, JAB ¼ 36.5. 13
C
{1H} NMR (CD2Cl2, 25 ꢂC)
d: 193.2 dt (CO, JCP ¼ JCP ¼ 9.0), 193.6 dt
(CO, JCP ¼ 42.0, JCP ¼ 9.0), 140.2 t (JCP ¼ 32.5), 139.2 d (JCP ¼ 55.5),
131.6 m,130.6 s,130.1 m, and 128.3 m (Ph), 64.8 d, 63.8 d, and 63.3 d
(CH2, JCP ¼ 8.0),16.2 m (CH3). C32H45Cl3GeO8P3Re (1015.82): calcd. C
37.84, H 4.47, Cl 10.47; found C 37.67, H 4.55, Cl 10.64%. 4b: IR (KBr
pellet) nCO: 1987, 1935 (s) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢂC)
d: 4.07 m
2.2. Synthesis of complexes
(18H, CH2), 1.32 t and 1.30 t (27H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢂC)
d
: AB2, dA 114.9, dB 113.1, JAB ¼ 46.5. C20H45Cl3GeO11P3Re (919.69):
The complexes MnCl(CO)5, ReCl(CO)5, MnCl(CO)3[PPh(OEt)2]2
and ReCl(CO)nP5ꢀn [n ¼ 2, 3; P ¼ PPh(OEt)2, P(OEt)3] were prepared
following the method previously reported [10a,13,14].
calcd. C 26.12, H 4.93, Cl 11.56; found C 26.01, H 5.07, Cl 11.78%.
2.2.4. Mn(GeH3)(CO)3[PPh(OEt)2]2 (5a) and Mn(GeH3)(CO)2
[PPh(OEt)2]3 (6a)
2.2.1. MnCl(CO)2[PPh(OEt)2]3
In a 50-mL three-necked round-bottomed flask were placed
0.8 mmol of the appropriate trichlorogermyl complex
Mn(GeCl3)(CO)n[PPh(OEt)2]5ꢀn (n ¼ 2, 3), an excess of LiAlH4
(16 mmol, 0.61 g), and 20 mL of thf. The reaction mixture was
stirred at room temperature for 30 min and then the solvent was
removed under reduced pressure. From the resulting solid, the
[Mn]eGeH3 complex was extracted with three 10-mL portions of
toluene using a cellulose column for the filtration. The extracts
were evaporated to dryness, leaving an oil which was triturated
with ethanol (3 mL). A white solid slowly separated out, which was
filtered and crystallised from ethanol and n-hexane; yield 55%. 5a:
An excess of PPh(OEt)2 (18.2 mmol, 3.6 mL) was added to
a solution of MnCl(CO)5 (3.65 mmol, 0.84 g) in toluene (30 mL) and
the reaction mixture was refluxed for 5 h. The solvent was removed
under reduced pressure and the oil obtained triturated with
ethanol (8 mL). An orange solid slowly separated out from the
resulting solution, which was filtered and crystallised from CH2Cl2
and ethanol; yield 80%. IR (KBr pellet) nCO: 1972, 1871 (s) cmꢀ1. 1H
NMR (CD2Cl2, ꢀ60 ꢂC)
d: 7.60 me7.18 m (15H, Ph), 4.06 m, 3.87 m,
3.73 m and 3.62 m (12H, CH2), 1.26 t, 1.23 t, 1.21 t, and 1.19 t (18H,
CH3) ppm. 31P{1H} NMR (CD2Cl2, ꢀ60 ꢂC)
d: A2B spin syst, dA 188.3,
dB 180.3, JAB ¼ 73.5 Hz C32H45ClMnO8P3 (741.01): calcd. C 51.87, H
IR (KBr pellet) nCO: 2001 (m), 1925, 1905 (s); nGeH: 1978 (m) cmꢀ1
.
6.12, Cl 4.78; found C 52.08, H 6.02, Cl 4.61%.
1H NMR (CD2Cl2, 25 ꢂC)
d: 7.61 m and 7.42 m (10H, Ph), 3.99 m and
3.84 m (8H, CH2), 2.62 t (3H, GeH3, JPH ¼ 4.5), 1.32 t (12H, CH3). 31
P
2.2.2. Mn(GeCl3)(CO)3[PPh(OEt)2]2 (1a) and Mn(GeCl3)(CO)2
[PPh(OEt)2]3 (2a)
{1H} NMR (CD2Cl2, ꢀ80 ꢂC)
d: A2, 199.7 (s). C23H33GeMnO7P2
(611.03): calcd. C 45.21, H 5.44; found C 45.02, H 5.56%. 6a: IR (KBr
In a 50-mL three-necked round-bottomed flask were placed
solid samples of the appropriate complex MnCl(CO)n[PPh(OEt)2]5ꢀn
(n ¼ 2, 3) (1.5 mmol), an excess of GeCl2ꢁdioxane (3 mmol, 0.7 g),
and 30 mL of 1,2-dichloroethane. The reaction mixture was
refluxed for 90 min (1a) or 180 min (2a). The solvent was removed
under reduced pressure to give an oil which was triturated with
ethanol (2 mL). A yellow (1a) or orange (2a) solid slowly separated
out, which was filtered and crystallised from toluene and n-hexane;
yield 85%. 1a: IR (KBr pellet) nCO: 2039 (m), 1980, 1960 (s) cmꢀ1. 1H
pellet) nCO: 1938, 1875 (s); nGeH: 1960 (sh) cmꢀ1. 1H NMR (CD3C6D5,
25 ꢂC)
d: 7.70 br and 7.09 br (15H, Ph), 3.94 me3.43 m (12H, CH2),
2.89 br (3H, GeH3), 1.07 br (18H, CH3); (ꢀ80 ꢂC): 2.90 m, br (3H,
GeH3). 31P{1H} NMR (CD3C6D5, ꢀ80 ꢂC)
d: A2B, dA 209.4, dB 196.9,
JAB ¼ 65.9. C32H48GeMnO8P3 (781.22): calcd. C 49.20, H 6.19; found
C 49.34, H 6.29%.
2.2.5. Re(GeH3)(CO)nP5ꢀn (7, 8) [n ¼ 3 (7), 2 (8); P ¼ PPh(OEt)2 (a),
P(OEt)3 (b)]
NMR (CD2Cl2, 25 ꢂC)
d
: 7.72 m and 7.49 m (10H, Ph), 4.12 m and
These complexes were prepared exactly like the related
3.96 m (8H, CH2), 1.38 t (12H, CH3). 31P{1H} NMR (CD2Cl2, ꢀ80 ꢂC)
d:
manganese complexes 5,
Re(GeCl3)(CO)nP5ꢀn and using a reaction time of 40 min; yield 60%.
7a: IR (KBr pellet) nCO: 2017 (m), 1938, 1919 (s) cmꢀ1 1H NMR
(CD3C6D5, 25 ꢂC)
: 7.63 m and 7.15 m (10H, Ph), 3.76 m and 3.54 m
(8H, CH2), 2.91 t (3H, GeH3, JPH ¼ 6.0), 1.07 t and 1.05 t (12H, CH3).
31P{1H} NMR (CD3C6D5, 25 ꢂC)
: A2, 134.1 (s). C23H33GeO7P2Re
(742.30): calcd. C 37.21, H 4.48; found C 37.42, H 4.54%. 8a: IR (KBr
pellet) nCO: 1970, 1885 (s) cmꢀ1. 1H NMR (CD3C6D5, 25 ꢂC)
: 7.88 m,
6
starting from 0.5 mmol of
A2, dA 188.0 (s). C23H30Cl3GeMnO7P2 (714.36): calcd. C 38.67, H 4.23,
Cl 14.89; found C 38.85, H 4.16, Cl 15.07%. 2a: IR (KBr pellet) nCO
:
.
1974, 1913 (s) cmꢀ1 1H NMR (CD2Cl2, 25 ꢂC)
.
d
: 7.81 m, 7.57 m,
d
7.48 m, and 7.40 m (15H, Ph), 4.00 me3.75 m (12H, CH2), 1.35 t, 1.34
t, and 1.28 t (18H, CH3). 31P{1H} NMR (CD2Cl2, ꢀ80 ꢂC)
d: A2B, dA
d
188.4, dB 187.0, JAB ¼ 72.0. C32H45Cl3GeMnO8P3 (884.55): calcd. C,
43.45; H, 5.13; Cl 12.02; found C 43.66, H 5.01, Cl 12.18%.
d
7.76 m, and 7.30 me6.97 m (15H, Ph), 3.95 m, 3.86 m, and 3.65 m
(12H, CH2), 2.83 dt (3H, GeH3, JPH ¼ JPH ¼ 5.5), 1.14 t, 1.12 t, and 1.08 t
2.2.3. Re(GeCl3)(CO)nP5ꢀn (3, 4) [ n ¼ 3 (3), 2 (4); P ¼ PPh(OEt)2 (a),
P(OEt)3 (b)]
In a 50-mL three-necked round-bottomed flask were placed
1.5 mmol of the appropriate complex ReCl(CO)nP5ꢀn, an excess of
(18H, CH3). 31P{1H} NMR (CD3C6D5, 25 ꢂC)
d
: AB2, dA 138.7, dB 135.2,
JAB ¼ 34.5. 13C{1H} NMR (CD3C6D5, 25 ꢂC)
d: 198.3 dt (CO, JCP ¼ 61.5,
JCP ¼ 10.7), 196.3 dt (CO, JCP ¼ JCP ¼ 9.6), 141.9 t (JCP ¼ 33.5), 140.9 d

G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
4193
(JCP ¼ 54.0), 131.7 d (JCP ¼ 12.0), 130.5 t (JCP ¼ 6.5), 129.2 m, 127.1 m,
and 125.0 s (Ph), 61.96 d, 61.78 d, and 61.50 d (CH2, JCP ¼ 8.0),
15.96 m (CH3). C32H48GeO8P3Re (912.49): calcd. C 42.12, H 5.30;
12a: IR (KBr pellet) nCO: 1988 (s), 1920 (sh), 1907 (s) cmꢀ1. 1H NMR
(CD2Cl2, 25 ꢂC)
: 7.68 m, 7.44 m, and 7.22 m (10H, Ph), 4.02 m,
3.87 m, and 3.74 m (8H, CH2), 1.35 t (12H, CH3 phos), 0.45 s (9H, CH3
d
found C 41.93, H 5.42%. 8b: IR (KBr pellet) nCO: 1955, 1890 (s); nGeH
1960 (sh) cmꢀ1 1H NMR (CD3C6D5, 25 ꢂC)
: 3.95 m (18H, CH2),
2.96 m (3H, GeH3), 1.16 t and 1.15 t (27H, CH3). 31P{1H} NMR
(CD3C6D5, 25 ꢂC)
AB2, dA 122.8, dB 121.7, JAB 47.0.
:
germyl). 31P{1H} NMR (CD2Cl2, ꢀ80 ꢂC)
d
: A2, 200.6 (s). 13C{1H} NMR
: 224.0 t (CO, JCP ¼ 26.0), 221.4 t (CO, JCP ¼ 29.5),
.
d
(CD2Cl2, 25 ꢂC)
d
141.3 t (JCP ¼ 32.5),140.6 br,130.4 t, br,129.8 m,129.4 s,128.6 m, and
125.7 s (Ph), 61.3 d, br (CH2), 16.4 d, br (CH3 phos), 7.60 s (CH3
germyl). C26H39GeMnO7P2 (653.11): calcd. C 47.81, H 6.02; found C
47.60, H 6.11%. 13a: IR (KBr pellet) nCO: 1953, 1885 (s) cmꢀ1. 1H NMR
d
:
¼
C20H48GeO11P3Re (816.36): calcd. C 29.43, H 5.93; found C 29.28, H
6.04%.
(CD2Cl2, 25 ꢂC)
d: 7.80 m, 7.55 m, and 7.38 m (15H, Ph), 3.80 m,
2.2.6. M[Ge(OEt)3](CO)nP5ꢀn (9e11) [M ¼ Mn (9), Re (10, 11); n ¼ 3
(9, 10), 2 (11); P ¼ PPh(OEt)2 (a), P(OEt)3 (b)]
3.70 m, and 3.55 m (12H, CH2), 1.25 t, 1.24 t, and 1.22 t (18H, CH3
phos), 0.20 s (9H, CH3 germyl). 31P{1H} NMR (CD2Cl2, 25 ꢂC)
d
: AB2,
In a 50-mL three-necked round-bottomed flask were placed
solid samples of the appropriate complex M(GeCl3)(CO)nP5ꢀn
(0.7 mmol), an excess of NaBH4 (14 mmol, 0.53 g), and 15 mL of
ethanol. The reaction mixture was stirred at room temperature
for 3 h and then the solvent was removed under reduced pressure
to give a solid from which the triethoxygermyl complex was
extracted with three 10-mL portions of toluene. The extracts were
evaporated to dryness, leaving an oil which was triturated with
ethanol (3 mL). A pale-yellow (Mn) or white (Re) solid slowly
separated out from the resulting solution, which was filtered and
crystallised from ethanol; yield 45%. 9a: IR (KBr pellet) nCO: 2022
dA 140.9, dB 133.5, JAB ¼ 40.0. 13C{1H} NMR (CD2Cl2, 25 ꢂC)
d: 200.4
dt (CO, JCP ¼ 63.4, JCP ¼ 10.5), 196.3 dt (CO, JCP ¼ JCP ¼ 9.5), 142.4 t
(JCP ¼ 30.0), 141.7 d (JCP ¼ 51.5), 131.7 d (JCP ¼ 13.0), 130.3 t
(JCP ¼ 6.0), 129.7 s, 127.9 m, and 127.5 d (JCP ¼ 9.5) (Ph), 62.80 d and
61.75 d (CH2, JCP ¼ 7.5), 16.4 m (CH3 phos), 8.51 d (CH3 germyl,
JCP ¼ 1.2). C35H54GeO8P3Re (954.57): calcd. C 44.04, H 5.70; found C
44.17, H 5.59%.
2.2.8. Mn[Ge(C^CPh)3](CO)3[PPh(OEt)2]2 (14a)
An excess of lithium acetylide LiþPhC^Cꢀ (3.0 mmol, 1.9 mL of
a 1.6 mol dmꢀ3 solution in thf) was added to a mixture of
Mn(GeCl3)(CO)3[PPh(OEt)2]2 (1a) (0.6 mmol, 0.43 g) in thf (15 mL)
cooled to ꢀ196 ꢂC. The reaction mixture was left to reach room
temperature and then stirred for 4 h. The solvent was removed
under reduced pressure to give an oil which was triturated with
ethanol (3 mL). A yellow solid slowly separated out from the
resulting solution, which was filtered and crystallised from toluene
and n-hexane; yield 55%. IR (KBr pellet) nC^C: 2145 (m); nCO: 2019
(m), 1952 (s, br) cmꢀ1. 1H NMR ([CD3]2CO, 25 ꢂC)
d: 7.90 m, 7.62 m,
and 7.44 m (10H, Ph), 4.22 m and 4.04 m (8H, CH2 phos), 3.89 q
(6H, CH2 germyl), 1.34 t (12H, CH3 phos), 1.18 t (9H, CH3 germyl).
31P{1H} NMR ([CD3]2CO, ꢀ80 ꢂC)
d
: A2, 195.9 (s). 13C{1H} NMR
([CD3]2CO, 25 ꢂC)
d: 220.0 t, br and 218.4 t, br (CO), 140.0 m,
131.2 m, 130.6 t (JCP ¼ 6.0), and 128.7 m (Ph), 62.8 d, br (CH2
phos), 59.23 s (CH2 germyl), 19.52 s (CH3 germy), 16.3 d, br (CH3
phos). C29H45GeMnO10P2 (743.19): calcd. C 46.87, H 6.10; found C
46.66, H 5.98%. 10a: IR (KBr pellet) nCO: 2033 (m), 1960, 1942 (s)
(m), 1944, 1934 (s) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢂC)
d: 7.78 m, 7.50 m,
and 7.32 m (25H, Ph), 4.15 m and 3.92 m (8H, CH2),1.35 t (12H, CH3).
cmꢀ1
.
1H NMR (CD3C6D5, 25 ꢂC)
d
: 7.86 m and 7.14 m (10H, Ph),
31P{1H} NMR (CD2Cl2, ꢀ80 ꢂC)
d
: A2, 193.9 (s). 13C{1H} NMR (CD2Cl2,
3.77 m and 3.56 m (8H, CH2 phos), 4.12 q (6H, CH2 germyl), 1.35 t
25 ꢂC)
d: 222.0 t, br and 219.8 br (CO), 140.0 m, 132.1 s, 132.0 s, 130.1
(9H, CH3 germyl), 1.20 t and 1.09 t (12H, CH3 phos). 31P{1H} NMR
t (JCP ¼ 6.0), 128.6 m, 128.1 m, and 125.0 s (Ph), 103.9 s (C
b), 98.4 t
(CD3C6D5, 25 ꢂC)
d
: A2, 131.3 (s). C29H45GeO10P2Re (874.46): calcd.
C 39.83, H 5.19; found C 39.99, H 5.31%. 11a: IR (KBr pellet) nCO
1960, 1910 (s) cmꢀ1 1H NMR (CD3C6D5, 25 ꢂC)
: 7.97 me6.98 m
(JCP ¼ 1.6, C ), 63.4 t (JCP ¼ 3.7, CH2), 16.3 t (JCP ¼ 3.4, CH3).
a
:
C47H45GeMnO7P2 (911.38): calcd. C 61.94, H 4.98; found C 61.78, H
5.11%.
.
d
(15H, Ph), 4.09 q (6H, CH2 germyl), 4.72 m and 3.50 m (12H, CH2
phos), 1.38 t (9H, CH3 germyl), 1.18 t and 1.17 t (18H, CH3 phos).
2.2.9. Re[GeCl2(SnCl3)](CO)2[PPh(OEt)2]3 (15a)
31P{1H} NMR (CD3C6D5, 25 ꢂC)
d
:
AB2, dA 136.4, dB 132.0,
: 201.0 dt, br and 197.5
An excess of SnCl2ꢁ2H2O (2.2 mmol, 0.50 g) was added to
a solution of Re(GeCl3)(CO)2[PPh(OEt)2]3 (4a) (0.5 mmol, 0.51 g)
in 25 mL of ethanol. The reaction mixture was refluxed for 2 h
and then the solvent was removed under reduced pressure to give
an oil which was triturated with ethanol (2 mL). A white solid
slowly separated out from the resulting solution, which was
filtered and crystallised from toluene and n-hexane; yield 80%. IR
JAB ¼ 36.5. 13C{1H} NMR (CD3C6D5, 25 ꢂC)
d
dt, br (CO), 142.2 m, 130.5 m, 129.5 m, and 127.3 m (Ph), 61.9 m
(CH2 phos), 58.7 s (CH2 germyl), 20.2 s (CH3 germy), 16.5 m (CH3
phos). C38H60GeO11P3Re (1044.64): calcd. C 43.69, H 5.79; found C
43.47, H 5.66%. 11b: IR (KBr pellet) nCO: 1980, 1910 (s) cmꢀ1 1H
.
NMR (CD3C6D5, 25 ꢂC)
CH2 phos), 1.36 t (9H, CH3 germyl), 1.24 t and 1.23 t (27H, CH3
phos). 31P{1H} NMR (CD3C6D5, 25 ꢂC)
: AB2, dA 120.6, dB 118.6,
d: 4.16 q (6H, CH2 germyl), 4.10 m (18H,
(KBr pellet) nCO: 2000, 1942 (s) cmꢀ1 1H NMR (CD2Cl2, 25 ꢂC)
. d:
d
7.52 m (15H, Ph), 4.05 me3.49 m (12H, CH2), 1.37 t, 1.35 t, and
31
JAB ¼ 46.0. C26H60GeO14P3Re (948.51): calcd. C 32.92, H 6.38;
1.23 t (18H, CH3). P{1H} NMR (CD2Cl2, 25 ꢂC)
d
: A2B, dA 137.5, dB
found C 33.15, H 6.51%.
134.1, JAB ¼ 29.5. 13C{1H} NMR (CD2Cl2, 25 ꢂC)
d: 193.3 m, br and
192.9 m, br (CO), 140.5 m, 131.8 m, 131.0 m, 130.5 m, and 128.7 m
2.2.7. Mn(GeMe3)(CO)3[PPh(OEt)2]2 (12a) and Re(GeMe3)(CO)2
[PPh(OEt)2]3 (13a)
(Ph), 65.0 d, 64.6 d, and 63.5 d (JCP ¼ 7.5, CH2), 16.0 m (CH3). 119Sn
{1H} NMR (CD2Cl2, 25 ꢂC)
(1205.44): calcd. C 31.88, H 3.76, Cl 14.71; found C 31.72, H 3.89, Cl
14.60%.
d
: ꢀ586.8 s C32H45Cl5GeO8P3ReSn
An excess of MgBrMe (3.0 mmol, 2.15 mL of a 1.4 mol dmꢀ3
solution in thf) was added to a mixture of the appropriate tri-
chlorogermyl complex M(GeCl3)(CO)nP5ꢀn (0.5 mmol) in toluene
(15 mL) cooled to ꢀ196 ꢂC. The reaction mixture was left to reach
room temperature and then stirred for 3 h. The solvent was
removed under reduced pressure to give a solid from which the
trimethylgermyl complex was extracted with three 8-mL portions
of toluene. The extracts were evaporated to dryness, leaving an oil
which was triturated with n-hexane (6 mL). A yellow (Mn) or white
(Re) solid slowly separated out from the resulting solution, which
was filtered and crystallised from toluene and n-hexane; yield 65%.
2.2.10. Reaction with CCl4
Carbon tetrachloride (0.3 mmol, 29 mL) was added to a solution
of the appropriate trihydridegermyl complex M(GeH3)(CO)nP5ꢀn
(5e8) (0.2 mmol) in toluene (10 mL) and the reaction mixture was
stirred for 12 h. The solvent was removed under reduced pressure
to give an oil which was triturated with ethanol (2 mL). A solid
slowly separated out, which was filtered and characterised as the
trichlorogermyl derivative M(GeCl3)(CO)nP5ꢀn (1e4); yield 80%.

4194
G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
2.3. Crystal structure determination of Re(GeCl3)(CO)2[PPh(OEt)2]3
(4a), Mn(GeH3)(CO)3[PPh(OEt)2]2 (5a) and Re(GeMe3)(CO)2
[PPh(OEt)2]3 (13a)
Cl
Cl
P
M
P
P
OC
OC
Cl
OC
OC
Ge
exc. GeCl2•dioxane
1,2-dichloroethane
M
Cl
CO
CO
Crystallographic data were collected on a Bruker Smart 1000
CCD diffractometer at CACTI (Universidade de Vigo) using graphite
P
1, 3 (I)
monochromated MoeK
a
radiation (
l
¼ 0.71073 Å), and were cor-
rected for Lorentz and polarisation effects. The software SMART
[15] was used for collecting frames of data, indexing reflections, and
the determination of lattice parameters, SAINT [16] for integration
of intensity of reflections and scaling, and SADABS [17] for empirical
absorption correction. The crystallographic treatment of the
compounds was performed with the Oscail program [18]. The
structures were solved by Patterson methods for 4a and 5a and by
direct methods for 13a. All were refined by a full-matrix least-
squares based on F2 [19]. Non-hydrogen atoms were refined with
anisotropic displacement parameters. Hydrogen atoms were
included in idealised positions and refined with isotropic
displacement parameters. Compound 4a crystallise in the P21/c
space group with two molecules in the asymmetric unit, but any
attempt to seek for another unit cell was unsuccessful. In the final
model of 4a one of the phosphonite groups in one molecule
resulted to be disordered due to an interchange in the position of an
ethoxy and a phenyl group, with an occupancy factor of 53:47.
Details of crystal data and structural refinement are given in Table 1.
Equation 1. M ¼ Mn (1), Re (3); P ¼ PPh(OEt)2 (a).
M(GeCl3)(CO)nP5ꢀn (1e4) which were isolated in good yields and
characterised (Eqns. (1) and (2)).
The reaction proceeds with the apparent insertion of GeCl2 into
the MeCl bond to afford trichlorogermyl complexes1e4, which
were isolated as solids and characterised. The insertion of
GeCl2ꢁdioxane into the MeCl bond to give [M]eGeCl3 (1e4) is slow
at room temperature and needs reflux conditions for good product
yields. It is worth noting that trichlorogermyl complexes 1e4 also
form starting from bromide precursors MBr(CO)nP5ꢀn, probably
through halide exchange between the first-formed trihalidegermyl
species [M]eGeBrCl2 and GeCl2 present in excess. The possibility of
a metathetic reaction of MBr(CO)nP5ꢀn with GeCl2, giving the
chloro-intermediate MCl(CO)nP5ꢀn, cannot be excluded.
Trichlorogermyl complexes M(GeCl3)(CO)nP5ꢀn (1e4) react with
LiAlH4
in
thf
to
give
trihydridegermyl
derivatives
M(GeH3)(CO)nP5ꢀn (5e8), which were isolated as yellow or white
solids and characterised (Schemes 1 and 2). Instead, the reaction of
complexes [M]eGeCl3 with NaBH4 in ethanol yielded triethox-
ygermyl derivatives M[Ge(OEt)3](CO)nP5ꢀn (9e11), which were
isolated and characterised (Schemes 1 and 2).
3. Results and discussion
3.1. Preparation of germyl complexes
When LiAlH4 is used as a reagent, trichlorogermyl complexes
[M]eGeCl3 undergo substitution of all three chlorides by Hꢀ,
affording synthesis of the first rhenium complexes containing
Chlorocarbonyl complexes MCl(CO)nP5ꢀn [M ¼ Mn, Re; n ¼ 2, 3;
P ¼ PPh(OEt)2, P(OEt)3] react with an excess of GeCl2ꢁdioxane in
refluxing 1,2-dichloroethane to give the trichlorogermyl derivatives
Table 1
Crystal data and structure refinement.
Identification code
4a
5a
13a
Empirical formula
Formula weight
Temperature
C64H90Cl6Ge2O16P6Re2
2031.46
173(2) K
C23H33O7P2GeMn
610.96
173(2) K
C35H54GeO8P3Re
954.48
173(2) K
Wavelength
0.71073 Å
0.71073 Å
0.71073 Å
Crystal system
Space group
Unit cell dimensions
Monoclinic
P21/c
Triclinic
Pꢀ1
Monoclinic
P21/n
a ¼ 21.989(2) Å
b ¼ 17.2025(18) Å
c ¼ 22.064(2) Å
a ¼ 10.118(2) Å
b ¼ 11.060(3) Å
c ¼ 13.009(3) Å
a ¼ 11.6510(9) Å
b ¼ 19.5557(15) Å
c ¼ 18.2112(14) Å
a
b
g
¼ 90ꢂ
a
b
g
¼ 97.859(5)ꢂ
¼ 98.612(4)ꢂ
¼ 92.856(5)ꢂ
a
b
g
¼ 90ꢂ
¼ 102.210(2)ꢂ
¼ 90ꢂ
¼ 99.6650(10)ꢂ
¼ 90ꢂ
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
8157.3(15) Å3
4
1422.3(6) Å3
2
4090.4(5) Å3
4
1.654 Mg/m3
4.060 mmꢀ1
4032
1.427 Mg/m3
1.650 mmꢀ1
628
1.550 Mg/m3
3.854 mmꢀ1
1920
Crystal size
0.48 ꢃ 0.27 ꢃ 0.22 mm
0.45 ꢃ 0.36 ꢃ 0.28 mm
0.48 ꢃ 0.35 ꢃ 0.22 mm
Theta range for data collection 1.51e25.03ꢂ
1.60e25.06ꢂ
1.54e25.00ꢂ
Index ranges
ꢀ26 ꢄ h ꢄ 26; ꢀ16 ꢄ k ꢄ 20; ꢀ26 ꢄ l ꢄ 25 ꢀ12 ꢄ h ꢄ 12; ꢀ13 ꢄ k ꢄ 9; ꢀ14 ꢄ l ꢄ 15 ꢀ13 ꢄ h ꢄ 13; ꢀ23 ꢄ k ꢄ 22; ꢀ10 ꢄ l<¼21
Reflections collected
Independent reflections
Reflections observed (>2
Data Completeness
Absorption correction
42,312
7495
21,245
14,362 [R(int) ¼ 0.0603]
4912 [R(int) ¼ 0.0205]
7148 [R(int) ¼ 0.0311]
s
)
9319
4098
5953
0.995
0.977
0.993
Semi-empirical from equivalents
1.000 and 0.580
Semi-empirical from equivalents
1.000 and 0.886
Full-matrix least-squares on F2
4912/0/323
Semi-empirical from equivalents
1.000 and 0.778
Max. and min. transmission
Refinement method
Full-matrix least-squares on F2
14362/0/965
Full-matrix least-squares on F2
7148/0/442
Data/restraints/parameters
Goodness-of-fit on F2
1.003
1.136
1.057
Final R indices [I > 2
R indices (all data)
Largest diff. peak and hole
s
(I)]
R1 ¼ 0.0433 wR2 ¼ 0.0934
R1 ¼ 0.0875 wR2 ¼ 0.1150
1.949 and ꢀ1.541 e Åꢀ3
R1 ¼ 0.0301 wR2 ¼ 0.0857
R1 ¼ 0.0418 wR2 ¼ 0.0989
0.571 and ꢀ0.566 e Åꢀ3
R1 ¼ 0.0222 wR2 ¼ 0.0489
R1 ¼ 0.0335 wR2 ¼ 0.0536
0.626 and ꢀ0.317 e Åꢀ3

G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
4195
Cl
Cl
H
H
P
M
P
P
P
OC
OC
Cl
P
OC
OC
Ge
P
OC
OC
Ge
P
exc. GeCl2•dioxane
1,2-dichloroethane
LiAlH4
thf
M
M
Cl
H
P
2, 4 (II)
P
Cl
Cl
6, 8 (IV)
P
OC
OC
Ge
P
Equation 2. M ¼ Mn (2), Re (4); P ¼ PPh(OEt)2 (a), P(OEt)3 (b).
M
Cl
P
2, 4
EtO
trihydridegermyl as a ligand. Conversely, in the case of manganese,
one example of a trihydridegermyl complex, Mn(GeH3)(CO)5, has
previously been reported [8c], by salt elimination reaction of
GeH3Br with Na[Mn(CO)5]. In any case, the reaction of tri-
chlorogermyl complexes 1e4 with LiAlH4 is an easy new method
for preparing trihydridegermyl complexes of Mn and Re.
OEt
P
M
P
OC
OC
Ge
P
NaBH4
EtOH
OEt
11 (VI)
Surprisingly, the reaction of trichlorogermyl [M]eGeCl3 with
NaBH4 in ethanol did not give the expected trihydridegermyl [M]e
GeH3, but the triethoxygermyl derivatives M[Ge(OEt)3](CO)nP5ꢀn
(9e11). With NaBH4 in ethanol, the reaction proceeds with
apparent substitution of the three chlorides of GeCl3 with OEtꢀ
giving [M]eGe(OEt)3 derivatives 9e11. The formation of triethox-
ygermyl species was not completely unexpected owing to the
known oxophilic nature of germanium [1e3], which gives stable
OH and OR derivatives. However, since [M]eGeH3 species are stable
in ethanol, NaBH4 does not produce [M]eGeH3 in the reaction with
[M]eGeCl3, but probably favors the reaction of the chlorogermyl
with ethanol yielding the final [M]-Ge(OEt)3 9e11 species.
Comparisons between the reactivity of manganese and rhenium
trichloro derivatives [M]eECl3 (E]Sn, Ge) and group-13 tetrahy-
drides BHꢀ4 and AlHꢀ4 highlighted how, with both Sn and Ge
elements, trihydride species [M]eEH3 were prepared. However,
although tin trihydride complexes [M]eSnH3 can be prepared with
only NaBH4 as reagent, since the reaction of [M]eSnCl3 with LiAlH4
gives decomposition products, trihydridegermyl derivatives [M]e
GeH3 were prepared only by the reaction of [M]eGeCl3 with LiAlH4.
The reaction of trichlorogermyl compounds with NaBH4 appears to
be interesting, since it reveals a new reaction by the GeCl3 ligand,
affording triethoxygermyl derivatives [M]eGe(OEt)3.
Scheme 2. M ¼ Mn (6), Re (8, 11); P ¼ PPh(OEt)2 (a), P(OEt)3 (b).
crystal structure determination of derivatives Re(GeCl3)(CO)2[P-
Ph(OEt)2]3 (4a) and Mn(GeH3)(CO)3[PPh(OEt)2]2 (5a).
The IR spectra of tricarbonyl derivatives M(GeCl3)(CO)3P2 (1, 3)
show one band of medium intensity and two strong bands, indi-
cating a mer arrangement of carbonyl ligands. In the temperature
range þ20 to ꢀ80 ꢂC, the 31P NMR spectra appear as sharp singlets,
suggesting the magnetic equivalence of the two phosphite ligands.
On the basis of these data, mer-trans geometry of type I (Eq. (1)) is
proposed for tricarbonyl complexes 1, 3.
The IR spectra of dicarbonyl derivatives M(GeCl3)(CO)2P3 (2, 4)
show two nCO bands at 1987e1913 cmꢀ1, indicating a mutually cis
arrangement of the two carbonyl ligands. The 13C NMR spectra also
show the magnetic inequivalence of the two CO groups, with two
clearly separated multiplets at 193.6 and 193.2 ppm for the
carbonyl carbon resonances of 4a. The 31P NMR spectrum of the
manganese complex 2a is a broad multiplet at room temperature,
and resolves into a well-resolved A2B pattern at ꢀ80 ꢂC. Instead, in
the temperature range þ20 to-80 ꢂC, the spectra of related rhenium
complexes4a and 4b appear as AB2 multiplets, which can be
simulated with the parameters reported in the Experimental
section. On the basis of these data, mer-cis geometry of type II (Eq.
(2)), like that found in the solid state, can be proposed in solution
for dicarbonyl derivatives 2,4.
Germyl complexes 1e11 were isolated as pale yellow (Mn) or
white (Re) solids stable in air and in solution of common organic
solvents, in which they behave as non-electrolytes [20]. Analytical
and spectroscopic data (IR and 1H, 13C, 31P NMR) support the
proposed formulation, which was further confirmed by X-ray
The IR spectra of tricarbonyl complexes M(GeH3)(CO)3P2 (5,7)
show the three nCO bands, one of medium intensity and two strong,
at 2017e1905 cmꢀ1, typical of the mer arrangement of the three
carbonyl ligands. A medium-intensity band at 1978 cmꢀ1 was also
observed for complex Mn(GeH3)(CO)3[PPh(OEt)2]2 (5a) and
attributed to one of the two nGeH bands. Instead, no band attrib-
utable to nGeH was observed in the spectra of rhenium complex 7a,
probably due to overlapping of the intense nCO absorptions.
However, the presence of the trihydridegermyl ligand was
confirmed by the 1H NMR spectra, which showed a triplet at 2.62
(5a) and 2.91 ppm (7a) due to the resonance of the GeH3 group.
Further confirmation of the presence of such a germyl ligand came
from X-ray crystal structure determination of 5a (see below).
In the temperature range þ20 to ꢀ80 ꢂC, the 31P NMR spectra of
complexes 5 and 7 are sharp singlets, fitting the magnetic equiva-
lence of the two phosphite ligands. Accordingly, mer-trans geom-
etry III (Scheme 1), like that found in the solid state, is proposed for
[M]eGeH3 derivatives 5, 7.
H
H
P
OC
OC
Ge
LiAlH4
thf
M
H
CO
P
Cl
Cl
5, 7 (III)
P
OC
OC
Ge
M
Cl
CO
P
1, 3
EtO
OEt
P
OC
OC
Ge
NaBH4
EtOH
M
OEt
CO
P
As well as two strong nCO bands, due to two CO ligands in
a mutually cis position, the IR spectra of dicarbonyl complexes
M(GeH3)(CO)2P3 (6, 8) show a shoulder of medium intensity near
9, 10 (V)
Scheme 1. M ¼ Mn (5, 9), Re (7, 10); P ¼ PPh(OEt)2 (a).

4196
G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
1960 cmꢀ1 (6a and 8b) attributable to the nGeH of the GeH3 group.
However, diagnostic for the presence of the trihydridegermyl
ligand are the 1H NMR spectra, which show a doublet of triplets at
2.96e2.83 ppm, attributed to the resonance of the GeH3 group. The
31P NMR spectra of manganese complex 6a is quite broad at room
temperature but, at ꢀ80 ꢂC, resolves into an A2B multiplet. In the
temperature range þ20 to ꢀ80 ꢂC, the 31P NMR spectra of rhenium
derivatives 8 are also AB2 multiplets, indicating that the two
phosphites or the two phosphonites are magnetically equivalent
and different from the third one. The 13C NMR spectra of
Re(GeH3)(CO)2[PPh(OEt)2]3 (8a) show two multiplets at 198.3 and
196.3 ppm, attributed to the carbon resonances of two carbonyl
ligands, which turned out to be magnetically non-equivalent. Mer-
cis geometry IV (Scheme 2) was thus proposed for dicarbonyl
complexes 6,8.
The IR spectra of triethoxygermyl derivatives M[Ge(O-
Et)3](CO)3P2 (9,10) show three nCO bands, one of medium intensity
and two strong, indicating a mer arrangement of the carbonyl
ligands. The 1H NMR spectra strongly support the presence of the
triethoxygermyl ligand, showing a quartet at 4.12e3.89 ppm of the
methylene and a triplet at 1.35e1.18 ppm of the methyl protons of
the ethoxy substituents. In an HMQC experiment, these signals
were correlated with both the singlets in the 13C spectrum of 9a, at
59.23 ppm of the methylene and 19.52 of the methyl carbon atoms,
indicating the presence of the Ge(OEt)3 group. In the temperature
range þ20 to ꢀ80 ꢂC, the31P NMR spectrum is a sharp singlet,
indicating the magnetic equivalence of the two phosphite ligands.
Accordingly, mer-trans geometry of type V (Scheme 1) is proposed
for tricarbonyl complexes 9, 10.
The IR spectra of dicarbonyl complexes Re[Ge(OEt)3](CO)2P3 (11)
show two strong nCO bands, indicating a mutually cis position of the
carbonyl groups. In the carbonyl carbon region, the 13C NMR spectra
of 11a show two multiplets at 201.0 and 197.5 ppm, indicating that
the two CO groups are not magnetically equivalent. The 13C spectra
also show methylene at 58.7 ppm and methyl at 20.2, resonances of
the ethoxy substituents of the Ge(OEt)3 ligands which, in an HMQC
experiment, are correlated with the quartet at 4.09 ppm of CH2 and
the triplet at 1.38 ppm of CH3 observed in the 1H NMR spectra and
indicating the presence of the triethoxygermyl group. As the 31P
NMR spectra are AB2 multiplets, mer-cis geometry of type VI
(Scheme 2) can be proposed for dicarbonyl complexes 11.
Since germyl complexes of manganese and rhenium are rather
rare [8,9], they were prepared by chemical or photochemical
reaction of Ge(IV) species such as R3GeX or H3GeX with appropriate
Mn and Re precursors. The insertion reaction of GeCl2 into the
MeCl bond of mixed-ligands complexes MCl(CO)nP5ꢀn allows easy
synthesis of trichlorogermyl complexes [M]eGeCl3, and the
subsequent reaction with LiAlH4 and NaBH4 reveals an easy route
for preparing both trihydridegermyl [M]eGeH3 and triethox-
ygermyl [M]eGe(OEt)3 derivatives.
H
H
CO2
NO REACTION
[M]
Ge
20 atm, RT
H
5 - 8
Equation 4. M ¼ Mn(CO)nP5ꢀn, Re(CO)nP5ꢀn; n ¼ 2, 3; P ¼ PPh(OEt)2 (a), P(OEt)3 (b).
give chloro-derivatives is classic for transition-metal hydrides [21]
and suggests the polyhydridic character of the GeH3 group. In order
to test this hypothesis, we reacted trihydridegermyl complexes
[M]eGeH3 with CO2, to verify whether insertion into the GeeH
bond giving germyl-formate [M]eGeH2{OC(H)]O} species would
occur. In mild conditions (1 atm), the carbon dioxide did not react
with any trihydridegermyl complex of Mn or Re. We then treated
both compounds Mn(GeH3)(CO)3P2 and Re(GeH3)(CO)2P3 with CO2
under pressure (20 atm) for 1 day, but also in this case no reaction
was observed and the trihydridegermyl complexes were quantita-
tively recovered unchanged (Eq. (4)).
This result was rather unexpected, because the related trihy-
dridestannyl complexes M(SnH3)(CO)nP5ꢀn quickly react with CO2
under mild conditions to give tin formate derivatives [10a,d] M[SnH
{OC(H)]O}2](CO)nP5ꢀn
dridegermyl complexes toward CO2 suggests the absence of a pol-
yhydridic character of the GeH3 group.
. The lack of reactivity of our trihy-
The perspective view of one of the molecules found in the
asymmetric unit of complex Re(GeCl3)(CO)2[PPh(OEt)2]3 (4a) is
shown in Fig. 1 and that of complex Mn(GeH3)(CO)3[PPh(OEt)2]2
(5a) in Fig. 2. Selected bond distances and angles are given in
Tables 2 and 3.
Compound 4a crystallises in the P21/c space group with two
molecules in the asymmetric unit, with the same distribution and
parametric properties within the error margin. In both, the
rhenium atom is coordinated by two carbonyl ligands in cis posi-
tions, three phosphorus atoms of two phosphonite ligands in mer
positions, and one germanium atom from a trichlorogermyl group.
The rhenium atom is coordinated in a slightly distorted octahedral
fashion. The cis angles range from 82.2(3) to 99.81(6)ꢂ. Both
extreme values imply the germyl ligand. The most highly deviated
trans angles are also, in both molecules, those for the carbon-
yleReeGe, with an average value of 170.4(2)ꢂ. The ReeC and ReeP
bond distances are similar to those found in other cis-dicarbonyl
mer-triphosphite complexes of rhenium [10aec,22]. Similarly, the
differing trans influence is also found in 4a, since the mutually trans
ReeP bond distances are about 0.08 Å (average between two
molecules) shorter than that trans to a carbonyl ligand. However,
O2
Trihydridegermyl complexes [M]eGeH3 react with CCl4 in
toluene to give trichlorogermyl complexes [M]eGeCl3 in good yield
(Eq. (3)).
O1
C2
P3
Cl2
C1
The reaction is fast and cannot be controlled to yield the inter-
mediate complexes [M]eGeH2Cl and [M]eGeHCl2 which form
during the course of the reaction. However, reaction with CCl4 to
Re1
Ge1
P2
P1
H
Cl
H
Cl
CCl4
Cl3
[M]
Ge
[M]
Ge
Cl1
toluene
H
Cl
Fig. 1. One of the molecules found in the asymmetric unit of complex 4a drawn at 30%
probability level. Atoms labeled as P1, P2 and P3 represent PPh(OEt)2 phosphonite
ligands.
5 - 8
1 - 4
Equation 3. M ¼ Mn(CO)nP5ꢀn, Re(CO)nP5ꢀn; n ¼ 2, 3; P ¼ PPh(OEt)2 (a), P(OEt)3 (b).

G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
4197
Table 3
H2
O2
Selected bond lengths [Å] and angles [ꢂ] for compound 5a.
Lengths
MneC(1)
C2
Ge
1.827(3)
1.806(3)
2.2162(8)
1.149(3)
1.143(3)
1.49(3)
MneC(2)
MneP(1)
MneGe
C(2)eO(2)
GeeH(1)
GeeH(3)
1.810(3)
H1
MneC(3)
MneP(2)
C(1)eO(1)
C(3)eO(3)
GeeH(2)
Angles
2.2252(8)
2.4731(6)
1.151(3)
1.43(3)
P2
H3
Mn
1.54(3)
C3
P1
C(3)eMneC(2)
C(2)eMneC(1)
C(2)eMneP(2)
C(3)eMneP(1)
C(1)eMneP(1)
C(3)eMneGe
C(1)eMneGe
P(1)eMneGe
MneC(2)eO(2)
MneGeeH(1)
H(1)eGeeH(2)
H(1)eGeeH(3)
99.56(13)
162.74(13)
88.76(9)
89.44(9)
90.43(9)
176.11(9)
79.20(9)
92.90(3)
C(3)eMneC(1)
C(3)eMneP(2)
C(1)eMneP(2)
C(2)eMneP(1)
P(2)eMneP(1)
C(2)eMneGe
P(2)eMneGe
MneC(1)eO(1)
MneC(3)eO(3)
MneGeeH(2)
MneGeeH(3)
H(2)eGeeH(3)
97.69(13)
89.31(9)
90.88(9)
90.31(9)
178.30(3)
83.54(9)
88.41(3)
178.0(3)
178.6(3)
114.5(14)
112.3(12)
103.5(17)
O3
C1
O1
Fig. 2. Perspective view of complex 5a. The ethoxy and phenyl groups were eliminated
for clarity. The hydrogen atoms of the germyl group were maintained.
178.4(3)
112.4(13)
107.9(19)
105.5(18)
the ReeC distances do not show such an influence, so the tri-
chlorogermyl ligand probably exerts a trans influence similar to that
of the phosphite ligand. The ReeGe bond distance is on average
2.557(1) Å. To our knowledge, there is no other published
or platinum [26]. In addition, the three ReeGeeCl angles differ
among themselves, since one of them is about 10ꢂ wider and
corresponds to that eclipsed (in each molecule) by the phosphonite
ligand. Dihedral angles which demonstrate this spatial arrange-
ment are the CleGeeReeP, on average 12.1(1)ꢂ. The spatial orien-
tation of the phosphonite ligands is such that those mutually trans
are found in an eclipsed fashion, with OePePeO or CePePeC
torsion angles in the range ꢀ4.9(5) to 2.2(3) . The two phenyl
substituents on those phosphanes are directed to the position of
the carbonyl ligand, dealing with CphenylePeReeCcarbonyl torsion
angles of average 18.5(5)ꢂ, with the result that an ethoxy group
[dihedral angles OePeReeP of average 16.2(3)ꢂ] is directed toward
the germyl ligand. The spatial disposition of the other phosphonite,
trans to a carbonyl ligand, is such that one of the ethoxy groups is
almost parallel to the other carbonyl ligand. One of the molecules is
disordered at this point, since one of the ethoxy and one phenyl
group occupy the same position and this disorder affects the other
two substituents of phosphorus and that parallel to the carbonyl
ligand is an ethoxy group. Dihedral angles CcarbonyleReePeO are
0.62(4)ꢂ for molecule 1 and ꢀ4.2(3)ꢂ for molecule 2.
compound with
flatediphenylgermyl ligand [9c] with
a
ReeGeR3 bond, apart from
a
tri-
a
bond distance of
2.4738(6) Å. Other ReeGe bonds found in the literature correspond
to bridging ligands and are longer, with bond distances between
2.5595(4) and 2.5999(8) Å [9a,23,24].The average bond angle at the
germanium atom is 108.5(1)ꢂ. However, the average ReeGeeCl
angle [120.4(1)ꢂ] is larger than the average CleGeeCl angle
[96.8(1)ꢂ]. This fact was expected and has previously been found in
other GeCl3 complexes with transition metals such as tungsten [25]
Table 2
Selected bond lengths [Å] and angles [ꢂ] for compound 4a.
Lengths
Re(1)eC(2)
Re(1)eC(1)
Re(1)eP(3)
Re(1)eP(2)
Re(1)eP(1)
Re(1)eGe(1)
Ge(1)eCl(1)
Ge(1)eCl(2)
Ge(1)eCl(3)
C(1)eO(1)
C(2)eO(2)
P(1)eO(12)
Angles
C(1)eRe(1)eC(2)
C(2)eRe(1)eP(3)
C(1)eRe(1)eP(3)
C(2)eRe(1)eP(2)
C(1)eRe(1)eP(2)
P(3)eRe(1)eP(2)
C(2)eRe(1)eP(1)
C(1)eRe(1)eP(1)
P(3)eRe(1)eP(1)
P(2)eRe(1)eP(1)
C(2)eRe(1)eGe(1)
C(1)eRe(1)eGe(1)
P(3)eRe(1)eGe(1)
P(2)eRe(1)eGe(1)
P(1)eRe(1)eGe(1)
Re(1)eC(1)eO(1)
Re(1)eC(2)eO(2)
Cl(1)eGe(1)eCl(2)
Cl(1)eGe(1)eCl(3)
Cl(2)eGe(1)eCl(3)
Cl(1)eGe(1)eRe(1)
Cl(2)eGe(1)eRe(1)
Cl(3)eGe(1)eRe(1)
1.924(10)
1.929(10)
2.369(2)
2.375(2)
2.459(2)
2.5550(10)
2.201(3)
2.224(3)
2.226(3)
1.148(10)
1.170(10)
1.608(7)
Re(2)eC(4)
Re(2)eC(3)
Re(2)eP(5)
Re(2)eP(6)
Re(2)eP(4)
Re(2)eGe(2)
Ge(2)eCl(5)
Ge(2)eCl(6)
Ge(2)eCl(4)
C(3)eO(3)
1.922(9)
1.963(9)
2.387(2)
2.397(2)
2.4461(19)
2.5594(9)
2.211(2)
2.213(3)
2.222(3)
1.147(9)
1.153(9)
1.603(5)
In 5a, the manganese ion is coordinated by three carbonyl
ligands in mer positions, two phosphorus atoms of two phos-
phonite ligands in trans positions, and one germanium atom from
a trihydridogermyl group. It should be noted that this is not the
C(4)eO(4)
P(4)eO(42)
main
disposition
for
tricarbonyldiphosphanemanganese
88.6(3)
90.4(3)
86.9(3)
89.2(3)
86.6(3)
C(3)eRe(2)eC(4)
C(4)eRe(2)eP(5)
C(3)eRe(2)eP(5)
C(4)eRe(2)eP(6)
C(3)eRe(2)eP(6)
P(5)eRe(2)eP(6)
C(3)eRe(2)eP(4)
C(4)eRe(2)eP(4)
P(5)eRe(2)eP(4)
P(6)eRe(2)eP(4)
C(3)eRe(2)eGe(2)
C(4)eRe(2)eGe(2)
P(5)eRe(2)eGe(2)
P(6)eRe(2)eGe(2)
P(4)eRe(2)eGe(2)
O(3)eC(3)eRe(2)
O(4)eC(4)eRe(2)
Cl(5)eGe(2)eCl(6)
Cl(5)eGe(2)eCl(4)
Cl(6)eGe(2)eCl(4)
Cl(6)eGe(2)eRe(2)
Cl(5)eGe(2)eRe(2)
Cl(4)eGe(2)eRe(2)
89.1(3)
84.0(2)
88.2(2)
86.9(2)
88.6(2)
complexes [27], but it has been found previously, for example, in
the closely related complex Mn(SnH3)(CO)3[PPh(OEt)2]2 [10a]. The
coordination polyhedron around the manganese may be defined as
an octahedron, but some distortion is found in the carbonyl-
173.52(8)
177.9(3)
89.4(2)
90.22(8)
89.97(8)
82.2(3)
170.7(2)
92.20(7)
94.14(6)
99.81(6)
176.7(8)
177.0(8)
96.92(13)
97.00(16)
96.35(13)
118.39(9)
114.17(8)
127.92(13)
170.39(7)
178.9(2)
91.0(2)
manganese-carbonyl axis, with
a
C(1)eMneC(2) angle of
162.7(1)ꢂ, bent toward the position occupied by the germyl ligand.
This feature had already been seen in similar compounds, like the
related complex Mn(SnH3)(CO)3[PPh(OEt)2]2 [10a] or the dinuclear
complex [Mn2(CO)10{P(C7H7)3}2] [28]. The other two axes are
almost linear [178.30(3) and 176.11(9)ꢂ)]. The cis angles are close to
the theoretical 90ꢂ, except those concerning the above-mentioned
carbonyl groups. Once again, the bond distances between the
carbonyl groups and the manganese atom in these compounds may
be a good indicator of the different trans influence, since two of
them are trans to each other and the third is trans to the germyl
group. However, the three values are all within the range of
experimental error, that trans to the germyl group being only
slightly shorter than the others. The trans influence of the trihy-
dridogermyl group seems to be similar to that of the carbonyl
90.71(7)
92.47(7)
81.1(2)
170.1(2)
96.09(5)
92.38(6)
98.86(5)
177.8(7)
177.0(7)
95.31(12)
97.23(11)
98.27(14)
118.73(9)
113.76(8)
127.29(9)

4198
G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
group. These MneC bond distance values are similar to those found
in previously reported mer-tricarbonylmanganese complexes
[10a,29]. The MneP distances are 2.2252(8) and 2.2162(8) Å,
significantly shorter than those found in other mer,trans-tricarbo-
nylbis(phosphinite)manganese complexes [10a,29]. The substitu-
ents on the phosphorus atoms are located in a pseudo-eclipsed
fashion, both phenyl groups following the direction of one of the
carbonyl groups, with torsion angles C(11)eP(1)eP(2)eC(21),
Cl
Me
Cl
Me
P
P
Re
P
OC
OC
Ge
P
OC
OC
Ge
P
MgBrMe
thf
Re
Cl
Me
P
4
13 (VIII)
O(11)eP(1)eP(2)eO(21),
and
O(12)eP(1)eP(2)eO(22)
of
Equation 5. P ¼ PPh(OEt)2 (a).
only ꢀ5.9(2),ꢀ10.9(1), and ꢀ9.8(1)ꢂ and C(11)eP(1)eMneC(1) and
C(21)eP(2)eMneC(1) of ꢀ14.9(1) and 9.1(1)ꢂ, respectively.
In conclusion, most of the geometrical features mentioned in
the description of compound 5a have previously been found in the
complex Mn(SnH3)(CO)3[PPh(OEt)2]2 [10a]. The only differences
between the complexes regard the substitution of a SnH3 ligand by
a GeH3 ligand and the evident change in the MneSn or MneGe
distances. The MneGe bond length, 2.4731(6) Å, is slightly longer
than those found in Mn(CO)5[Ge(CF3)3], 2.4132(9) Å [8b], or in the
anion [Mn(CH3Cp)(CO)2(GeH3)]ꢀ [30]. The GeeH bond lengths
[range 1.43(3) ꢀ 1.54(3) Å] are slightly longer than those found in
germanium hydride complexes of alkaline metals [31], but these
values may be misleading due to the well-known limitations of X-
ray diffractometry for hydrogen atoms in the proximity of heavy
metals. The angles around the germanium atom, ranging from
103.5(2) to 114.5(1) , confirm the sp3 character of this atom.
room temperature, whereas in reflux conditions many decompo-
sitions are observed, which prevent preparation of trialkynylgermyl
complexes of rhenium.
The new organogermyl complexes 12e14 were isolated as
yellow (12, 14) or white (13) solids, stable in air and in solution of
common organic solvents, where they behave as non-electrolytes
[20]. Analytical and spectroscopic data (IR and 1H, 13C, 31P NMR)
support the proposed formulation for the compounds, which was
further confirmed by X-ray crystal structure determination of
complex Re(GeMe3)(CO)2[PPh(OEt)2]3 (13a).
Diagnostic for the presence of the germyl GeMe3 and
Ge(C^CPh)3 ligands were both IR and 1H and 13C NMR spectra. The
proton spectrum of complex Mn(GeMe3)(CO)3[PPh(OEt)2]2 (12a)
shows a sharp singlet at 0.45 ppm which, in an HMQC experiment,
was correlated with the singlet at 7.60 ppm in the 13C NMR spec-
trum and attributed to the methyl resonance of the GeMe3 ligand.
In the related rhenium complex 13a, methyl resonance falls at
0.20 ppm in the proton NMR spectrum, and at 8.51 ppm in the 13C
spectrum, matching the presence of the GeMe3 ligand.
The IR spectrum of trialkynylgermyl complex Mn
[Ge(C^CPh)3](CO)2[PPh(OEt)2]3 (14a) shows a medium-intensity
band at 2145 cmꢀ1, attributed to the nC^C of the acetylide ligands.
However, the presence of the trialkynylgermyl ligand was
confirmed by the 13C NMR spectrum, with a triplet at 98.4 ppm
3.2. Reactivity
The easy substitution of chloride by either Hꢀ or OEtꢀ in the
coordinate GeCl3 group, to give trihydridegermyl [M]-GeH3 and
triethoxygermyl [M]eGe(OEt)3 derivatives, prompted us to extend
study to the substitution reaction of [M]eGeCl3 complexes 1e4
with other nucleophilic reagents. The results are shown in Scheme
3 and Eq. (5).
The manganese complex Mn(GeCl3)(CO)3[PPh(OEt)2]2 (1a)
reacts with both Grignard reagent MgBrMe and lithium acetylide
LiþPhC^Cꢀ to give trimethylgermyl complex Mn(GeMe3)(CO)3[P-
(JCP ¼ 1.6 Hz), attributed to the C
coupled with the two phosphites, and a singlet at 103.9 ppm, due to
carbon resonance, matching the presence of the Ge(C^CPh)3
group.
The IR and NMR data also suggest mer-trans geometry in solu-
tion for manganese complexes 12a and 14a: one medium-intensity
band and two strong ones in the nCO region of the IR spectra suggest
a mer arrangement of the three CO groups, whereas the sharp
singlet observed in the 31P spectra at ꢀ80 ꢂC indicates the magnetic
equivalence of the two phosphite ligands, matching with type VII
geometry (Scheme 3).
a carbon resonance of the acetylide
Cb
Ph(OEt)2]2
(12a)
and
trialkynylgermyl
derivative
Mn
[Ge(C^CPh)3](CO)2[PPh(OEt)2]3 (14a), respectively, which were
isolated in the solid state and characterised. The related rhenium
complexes Re(GeCl3)(CO)nP5ꢀn also react with an excess of MgBrMe
to give trimethylgermyl complexes [Re]eGeMe3, but only in the
case of dicarbonyl Re(GeMe3)(CO)2[PPh(OEt)2]3 (13a) was the
compound isolated as a solid and characterised. Instead, the reac-
tion of Re(GeCl3)(CO)nP5ꢀn with LiþPhC^Cꢀ does not proceed at
Instead, mer-cis geometry of type VIII (Eq. 5) is proposed for
dicarbonyl
compound
Mn(GeMe3)(CO)2[PPh(OEt)2]3
(13a),
Me
Me
according to both IR and NMR data. The IR spectrum shows two nCO
bands of two carbonyls in a mutually cis position, whereas the 31P
NMR spectrum appears as an AB2 multiplet indicating that two
phosphites are magnetically equivalent and different from the
third. In addition, the 13C NMR spectrum shows two multiplets in
the carbonyl carbon region, indicating that the two CO ligands are
not magnetically equivalent, as expected for type VIII geometry.
The perspective view of one of the two molecules found in the
asymmetric unit of compound Re(GeMe3)(CO)2[PPh(OEt)2]3 (13a)
is shown in Fig. 3. Selected bond distances and angles for both
molecules are given in Table 4. In this compound, the coordination
of the rhenium atom is similar to that found in 4a with the only
difference that the germanium atom comes from a trimethylgermyl
GeMe3 group instead of a GeCl3. The other ligands are also three
phosphonite ligands in mer positions and two carbonyl ligands in
cis positions. The ReeC bond lengths are 1.928(4) and 1.942(3) Å,
the shorter one corresponding to that trans to the phosphonite
P
OC
OC
Ge
MgBrMe
thf
Mn
Me
CO
P
Cl
Cl
P
12 (VII)
OC
OC
Ge
Mn
CPh
C
Cl
CPh
CO
P
C
P
1
OC
OC
Ge
CO
Li+PhC C–
thf
Mn
C
P
CPh
14 (VII)
Scheme 3. P ¼ PPh(OEt)2 (a).

G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
4199
O1
P3
O1
O2
C1
O2
O2
O1
C1
C2
C2
C1
C2
P1
Re
Re
C3
Re1
O12
Cl2
Ge1
C4
Ge
C11
P1
C11
P1
Ge
Cl1
O12
P2
O11
O11
Cl3
C5
Fig. 4. View of complexes 4a (left) and 13a (right) along the PeReeP axis.
Fig. 3. Perspective view of complex 13a. The ethoxy and phenyl groups were elimi-
nated for clarity. The hydrogen atoms on the methyl groups of the germyl were
maintained.
two sets of values between the methyl-germanium-rhenium
angles, those of about 113.7(2)ꢂ and another one of 121.3(1)ꢂ, the
last corresponding to that eclipsed by the phosphonite ligand
[dihedral angle C(4)eGeeReeP(1) of 0.2(2)ꢂ]. The same sterical
effect is found in 4a. There are considerable differences between
GeCl3 (4a) and Ge(CH3)3 (13a), since CleGeeCl angles are slightly
more acute than in CeGeeC.
Trichlorogermyl complexes [M]eGeCl3 were also reacted with
SnCl2ꢁ2H2O to verify whether the GeeCl bond may undergo not
only substitution, but also an insertion reaction of the SnCl2 group.
The reaction did proceed in refluxing ethanol to give the stannyl-
germyl complex Re[GeCl2(SnCl3)](CO)2[PPh(OEt)2]3 (15a), which
was isolated in good yield and characterised (Eq. (6)).
SnCl2 inserts into only one of the GeeCl bonds of the coordinate
[M]eGeCl3 to give the stannyl-dichlorogermyl derivative [M]-
GeCl2(SnCl3) (15). This result prompted us to study the reaction of
the related trichlorostannyl complex [10a] Re(SnCl3)(CO)2[P-
Ph(OEt)2]3 with GeCl2ꢁdioxane, to test whether the GeCl2 group can
also insert into the SneCl bond of the coordinate SnCl3 group to
ligand, indicating that the trimethylgermyl group may exert
a slightly higher trans influence than the phosphonite. The ReeP
bond distances range from 2.3668(9) to 2.3988(8) Å, those mutually
trans being slightly shorter than the one trans to the carbonyl
ligand. It is noteworthy that substitution of a GeCl3 ligand for
a GeMe3 shortens the ReeP bond length trans to a carbonyl, a clear-
cut effect of the electron enrichment of the rhenium atom. Again,
the polyhedron around the metal is best described as an octahe-
dron, but with some distortion, as can be seen in the cis angles,
which range from 79.5(1) to 95.7(1)ꢂ. The trans angles range from
169.72(3) to 175.3(1)ꢂ, showing a distortion slightly higher than
that of the former complex. The spatial orientation of the mutually
trans phosphonite ligands is similar to that found in 4a, with an
eclipsed disposition and one of the ethoxy groups directed toward
the germyl group [dihedral angles OePeReeGe of 14.4(1)ꢂ].
However, the disposition of the other phosphonite ligand is quite
unlike that found for compound 4a, since the phenyl moiety is now
almost entirely eclipsed by the carbonyl, when compared with that
for 4a, as shown in Fig. 4 .
The GeeCmethyl distances range from 1.981(4) to 2.026(3) Å, only
slightly longer than those found in a ruthenium Ge(CH3)3 complex
[32], but similar to those in a niobium complex [33]. The angles
around germanium atoms correspond to the sp3 character of this
atom. Methyl-germanium-methyl angles range from 98.2(2) to
103.4(2)ꢂ, more acute than methyl-germanium-rhenium ones. This
effect was also found in the above-mentioned niobium or ruthe-
nium complexes, although differences are higher for 13a. There are
give
stannyl-germyl
derivatives.
Surprisingly,
complex
Re(SnCl3)(CO)2P3 reacted with an excess of GeCl2ꢁdioxane to give
the trichlorogermyl derivative Re(GeCl3)(CO)2P3 (4) in good yield
(Eq. (7)).
The reaction does not proceed with the insertion of GeCl2 into
the SneCl bond, but rather with the apparent substitution of the
SnCl3 ligand with GeCl3, giving the known trichlorogermyl deriv-
ative. Therefore, only the coordinate trichlorogermyl group [Re]-
GeCl3 yields metal complexes (15) containing mixed germyl-
stannyl species of the type GeCl2(SnCl3) as ligands.
The reactivity of complex Re[GeCl2(SnCl3)](CO)2[PPh(OEt)2]3
(15a) with NaBH4 and LiAlH4 was studied, and the results are
shown in Scheme 4.
Table 4
The reaction of 15a with LiAlH4 proceeds with the substitution
by Hꢀ, not only of the two germanium-bonded chlorides, but also of
SnCl3, giving trihydridegermyl complex Re(GeH3)(CO)2[PPh(OEt)2]3
(8a). Conversely, the reaction with NaBH4 in ethanol does not give
any hydridegermyl complex, but does yield triethoxygermyl
derivative Re[Ge(OEt)3](CO)2[PPh(OEt)2]3 (11a) formed by substi-
tution of both Clꢀ and SnCl3 groups with OEtꢀ. In every case, the
reaction of 15a with hydrurating agents such as NaBH4 and LiAlH4
Selected bond lengths [Å] and angles [ꢂ] for compound 13a.
Lengths
ReeC(2)
ReeP(3)
ReeP(1)
C(1)eO(1)
GeeC(4)
GeeC(3)
Angles
1.928(4)
2.3668(9)
2.3988(8)
1.147(4)
1.981(4)
2.026(3)
ReeC(1)
ReeP(2)
ReeGe
C(2)eO(2)
GeeC(5)
1.942(3)
2.3691(9)
2.6383(4)
1.158(4)
1.992(3)
C(2)eReeC(1)
C(1)eReeP(3)
C(1)eReeP(2)
C(2)eReeP(1)
P(3)eReeP(1)
C(2)eReeGe
P(3)eReeGe
P(1)eReeGe
ReeC(2)eO(2)
C(3)eGeeRe
C(4)eGeeRe
C(5)eGeeRe
95.73(14)
87.77(10)
87.40(10)
91.76(10)
92.70(3)
175.26(10)
93.38(3)
92.97(2)
C(2)eReeP(3)
C(2)eReeP(2)
P(3)eReeP(2)
C(1)eReeP(1)
P(2)eReeP(1)
C(1)eReeGe
P(2)eReeGe
ReeC(1)eO(1)
C(4)eGeeC(3)
C(4)eGeeC(5)
C(5)eGeeC(3)
86.10(10)
85.35(10)
169.72(3)
172.50(11)
93.27(3)
79.53(11)
94.66(2)
178.0(3)
Cl
Cl
Cl
Cl
P
P
OC
OC
Ge
P
OC
OC
Ge
P
exc. SnCl2•H2O
EtOH
Cl
Cl
Re
Re
Cl
Sn
P
P
177.1(3)
103.41(16)
103.32(16)
98.19(16)
Cl
113.82(10)
121.33(11)
113.73(12)
4
15
Equation 6. P ¼ PPh(OEt)2 (a).

4200
G. Albertin et al. / Journal of Organometallic Chemistry 696 (2012) 4191e4201
Acknowledgment
Cl
Cl
Cl
Cl
P
Re
P
P
The financial support of MIUR (Rome)-PRIN 2009 is gratefully
acknowledged. We thank Mrs. Daniela Baldan, from the Università
Ca’ Foscari Venezia (Italy), for her technical assistance.
OC
Sn
P
OC
OC
Ge
P
exc. GeCl2•diox
Re
Cl
Cl
OC
P
Appendix A. Supplementary material
4
Equation 7. P ¼ PPh(OEt)2 (a).
CCDC 826335-826336-826337 contains the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
H
H
P
OC
Ge
P
LiAlH4
thf
Re
References
H
OC
Cl
Cl
P
P
8
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