Preparation and reactivity of germyl complexes of ruthenium and osmium stabilised by cyclopentadienyl, indenyl and tris(pyrazolyl) borate fragments

Article abstract of DOI:10.1016/j.jorganchem.2013.06.028

Half-sandwich trichlorogermyl complexes Ru(GeCl₃) (η⁵-C₅H₅)(PPh₃)L (1) and Ru(GeCl₃)(η⁵-C₉H₇)(PPh ₃)L (2) [L=P(OMe)₃ (a), P(OEt)₃ (b) and PPh(OEt)₂ (c)] were prepared by allowing chloro compounds RuCl(η⁵-C₅H₅)(PPh₃)L and RuCl(η⁵-C₉H₇)(PPh₃)L to react with an excess of GeCl₂ · dioxane in ethanol. Treatment of trichlorogermyl complexes 1 and 2 with LiAlH₄ in THF yielded trihydridogermyl derivatives Ru(GeH₃)(η⁵-C ₅H₅)(PPh₃)L (3) and Ru(GeH₃) (η⁵-C₉H₇)(PPh₃)L (4). Instead, reaction of trichlorogermyl complexes 1 and 2 with NaBH₄ in ethanol afforded triethoxygermyl complexes Ru[Ge(OEt)₃](η⁵- C₅H₅)(PPh₃)L (5) and Ru[Ge(OEt) ₃](η⁵-C₉H₇)(PPh₃)L (6). Trichlorogermyl complexes with the tris(pyrazolyl) borate ligand M(GeCl₃)(Tp)(PPh₃)L [M=Ru (7), Os (10)] were prepared by reacting chloro compounds MCl(Tp)(PPh₃)L with an excess of GeCl ₂ · dioxane. Depending on metal centre, nature of phosphite and experimental conditions, the reaction of trichlorogermyl complexes 7 and 10 with LiAlH₄ or NaBH₄ afforded trihydridogermyl M(GeH ₃)(Tp)(PPh₃)L (8, 12) and triethoxygermyl derivatives M [Ge(OEt)₃](Tp)(PPh₃)L (9, 11). The complexes were characterised by IR and multinuclear NMR spectroscopy and by X-ray crystal structure determination of 3a.

Full text of DOI:10.1016/j.jorganchem.2013.06.028

Journal of Organometallic Chemistry 751 (2014) 412e419
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Preparation and reactivity of germyl complexes of ruthenium and
osmium stabilised by cyclopentadienyl, indenyl and tris(pyrazolyl)
borate fragments
,
a
b
a
Gabriele Albertin a , Stefano Antoniutti , Jesús Castro , Federica Scapinello
*
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
Half-sandwich trichlorogermyl complexes Ru(GeCl3)(h h
5-C5H5)(PPh3)L (1) and Ru(GeCl3)( 5-C9H7)(PPh3)L
Article history:
Received 29 May 2013
Received in revised form
20 June 2013
(2) [L ¼ P(OMe)3 (a), P(OEt)3 (b) and PPh(OEt)2 (c)] were prepared by allowing chloro compounds
RuCl(
5-C5H5)(PPh3)L and RuCl( 5-C9H7)(PPh3)L to react with an excess of GeCl2$dioxane in ethanol.
Treatment of trichlorogermyl complexes 1 and 2 with LiAlH4 in THF yielded trihydridogermyl derivatives
Ru(GeH3)(
5-C5H5)(PPh3)L (3) and Ru(GeH3)( 5-C9H7)(PPh3)L (4). Instead, reaction of trichlorogermyl
complexes 1 and 2 with NaBH4 in ethanol afforded triethoxygermyl complexes Ru[Ge(OEt)3](h5
C5H5)(PPh3)L (5) and Ru[Ge(OEt)3](
5-C9H7)(PPh3)L (6). Trichlorogermyl complexes with the tris(pyr-
h
h
Accepted 21 June 2013
h
h
-
Keywords:
Synthesis
h
azolyl)borate ligand M(GeCl3)(Tp)(PPh3)L [M ¼ Ru (7), Os (10)] were prepared by reacting chloro com-
pounds MCl(Tp)(PPh3)L with an excess of GeCl2$dioxane. Depending on metal centre, nature of
phosphite and experimental conditions, the reaction of trichlorogermyl complexes 7 and 10 with LiAlH4
or NaBH4 afforded trihydridogermyl M(GeH3)(Tp)(PPh3)L (8, 12) and triethoxygermyl derivatives M
[Ge(OEt)3](Tp)(PPh3)L (9, 11). The complexes were characterised by IR and multinuclear NMR spec-
troscopy and by X-ray crystal structure determination of 3a.
Trihydridogermyl and triethoxygermyl
Half-sandwich complexes
Ruthenium and osmium
Tris(pyrazolyl)borate ligand
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
studies to both half-sandwich and tris(pyrazolyl)borate complexes
of the iron triad of the types MCl(h h
5-C5H5)PPh3L, MCl( 5-C9H7)
The chemistry of transition metal complexes containing tri-
chlorogermyl GeCl3 or triorganogermyl GeR3 as ligands has been
extensively studied over several decades [1e3], both from a
fundamental point of view and because these complexes are
regarded as intermediates in a number of transition metal-
catalysed transformations of group-14 element compounds [4,5].
A number of germyl complexes of several metals have thus been
prepared, containing both mononuclear GeCl3 and GeR3 and poly-
nuclear [GeR2GeR2GeR2] germyl groups, but relatively few have
been reported with trihydridogermyl GeH3 as ligand [6].
We are interested in the synthesis and reactivity of germyl
complexes of transition metals and have recently reported [7,8] the
synthesis and reactivity of trihydrido- [M]eGeH3 and organo-
germyl [M]eGeR3 (R ¼ Me, OEt, PhC^C) derivatives of Mn and Re,
and the preparation of osmium complexes containing an oxo-
germanium cluster as ligand. We have now extended these
PPh3L, and MCl(Tp)PPh3L [M ¼ Ru, Os; Tp ¼ tris(pyrazolyl)borate;
L ¼ phosphite] and this paper reports the preparation and char-
acterisation of new germyl complexes, including the first trihy-
dridogermyl derivatives of ruthenium and osmium.
2. Experimental section
2.1. General comments
All synthetic work was carried out in an appropriate inert at-
mosphere (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 ꢁC.
All solvents were dried over appropriate drying agents, degassed on
a vacuum line, and distilled into vacuum-tight storage flasks.
RuCl3$3H2O and OsO4 were obtained from Pressure Chemical Co.
(USA) and used as received. Phosphonite PPh(OEt)2 was prepared
by the method of Rabinowitz and Pellon [9], while P(OMe)3 and
P(OEt)3 were obtained from SigmaeAldrich Co. (USA) and purified
by distillation under nitrogen. GeCl2$dioxane, NaBH4, and LiAlH4
* Corresponding author. Fax: þ39 041 234 8917.
E-mail address: albertin@unive.it (G. Albertin).
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.06.028

G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
413
were also obtained from SigmaeAldrich Co. (USA) and used as
received. Other reagents were purchased from commercial sources
in the highest available purity and used as received.
25 ꢁC)
d
: AB, dA 149.85, dB 51.1, JAB ¼ 61.0. C26H29Cl3GeO3P2Ru
(731.52): calcd. C 42.69, H 4.00, Cl 14.54; found C 42.85, H 4.17, Cl
14.69%.
Infrared spectra were recorded on a PerkineElmer Spectrum-
One FT-IR spectrophotometer. NMR spectra (1H, 13C, 31P) were ob-
tained on an AVANCE 300 Bruker spectrometer at temperatures
between ꢀ90 and þ30 ꢁC, unless otherwise noted. 1H spectra are
referred to internal tetramethylsilane; 31P{1H} chemical shifts are
reported with respect to external 85% H3PO4, with downfield shifts
considered positive. The iNMR software package [10] was used to
treat NMR data. The conductivity values of 10ꢀ3 mol dmꢀ3 solutions
of the complexes in CH3NO2 at 25 ꢁC were measured on a Radi-
ometer CDM 83. Elemental analyses were determined in the
Microanalytical Laboratory of the Dipartimento di Scienze del
Farmaco, University of Padova (Italy).
1b: 1H NMR (CD2Cl2, 25 ꢁC)
d
: 7.50e7.18 (m, 15H, Ph), 4.72 (s, 5H,
Cp), 3.88 and 3.84 (m, 6H, CH2), 1.15 (t, 9H, CH3). 31P{1H} NMR
(CD2Cl2, 25 ꢁC)
AB, dA 154.0, dB 60.55, JAB 61.5.
29H35Cl3GeO3P2Ru (773.60): calcd. C 45.02, H 4.56, Cl 13.75; found
d
:
¼
C
C 44.80, H 4.66, Cl 13.60%.
1c: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.42e7.10 (m, 20H, Ph), 4.92 (s, 5H,
Cp), 4.13, 3.87, 3.65 and 3.55 (m, 4H, CH2), 1.37 and 1.13 (t, 6H, CH3).
31P{1H} NMR (CD2Cl2, 25 ꢁC)
: AB, dA 167.2, dB 49.6, JAB ¼ 52.2.
33H35Cl3GeO2P2Ru (805.65): calcd. C 49.20, H 4.38, Cl 13.20; found
d
C
C 49,42, H 4.51, Cl 13.39%.
2a: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.76e7.00 (m, 15H, Ph), 6.75 (t, 2H,
H5 þ H6 Ind), 6.17 (d, 2H, H4 þ H7), 5.42 (t,1H, H2 Ind), 5.40 (br, 1H,
H3 Ind), 3.51 (d, 9H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA
146.8, dB 50.2, JAB ¼ 60.8. C30H31Cl3GeO3P2Ru (781.58): calcd. C
2.2. Synthesis of complexes
46.10, H 4.00, Cl 13.61; found C 45.87, H 4.12, Cl 13.41%.
2b: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.74e6.97 (m, 15H, Ph), 6.82 (t m,
The compounds RuCl(
OsCl(Tp)(PPh3)L [L ¼ P(OMe)3, P(OEt)3, PPh(OEt)2] [11a] and
RuCl(
5-C9H7)(PPh3)2 [11b] were prepared following the methods
previously reported.
h
5-C5H5)(PPh3)L, RuCl(Tp)(PPh3)L,
2H, H5 þ H6 Ind), 6.05 (d, 2H, H4 þ H7 Ind), 5.46 (m, 1H, H2 Ind),
5.36 (br, 1H, H3 Ind), 4.48 (br, 1H, H1 Ind), 3.87 (m, 6H, CH2), 1.20 (t,
h
9H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 141.6, dB 49.7,
JAB ¼ 60.8. C33H37Cl3GeO3P2Ru (823.66): calcd. C 48.12, H 4.53, Cl
2.2.1. RuCl(
h
5-C9H7)(PPh3)L [L ¼ P(OMe)3, P(OEt)3]
12.91; found C 48.34, H 4.39, Cl 12.70%.
An excess of the appropriate phosphite L (6.0 mmol) was added
h
5-C9H7)(PPh3)L (4)
to a solution of RuCl(h
5-C9H7)(PPh3)2 (1.29 mmol, 1.0 g) in THF
2.2.3. Ru(GeH3)(Cp)(PPh3)L (3) and Ru(GeH3)(
[L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c)]
(30 mL) and the reaction mixture was refluxed for 30 min. The
solvent was removed under reduced pressure to give an oil, which
was treated with the appropriate alcohol ROH (10 mL). The
resulting solution was stirred for about 1 h and then cooled
to ꢀ25 ꢁC. After some days, an orange solid separated out, which
was filtered and crystallised from CH2Cl2 and ethanol; yield 75%.
In a 50-mL three-necked round-bottomed flask were placed
solid samples of the appropriate complex Ru(GeCl3)(Cp)(PPh3)L (1)
and Ru(GeCl3)(h
5-C9H7)(PPh3)L (2) (0.4 mmol), an excess of LiAlH4
(8 mmol, 0.30 g), and 20 mL of THF. The reaction mixture was
stirred at room temperature for 1 h and then the solvent was
removed under reduced pressure leaving a solid from which the
complex was extracted with three 10-mL portions of toluene using
a cellulose column (3 cm) for filtration. Extracts were evaporated to
dryness to give an oil which was triturated with ethanol (3 mL). A
yellow solid separated out, which was filtered and dried under
vacuum; yield 70%.
4
3
3a
5
2
6
7a
1
3a: IR (KBr pellet) nGeeH: 1949, 1924 (m) cmꢀ1
.
1H NMR
7
(CD3C6D5, 25 ꢁC)
d: 7.58, 7.30 and 7.04 (m, 15H, Ph), 4.52 (s, 5H, Cp),
L ¼ P(OMe)3: 1H NMR (CD2Cl2, 25 ꢁC)
d
: 7.65e7.25 (m, 15H, Ph),
ABX3 spin syst, dx 3.25, JAx ¼ 3.2, JBx ¼ 1.2 (3H, GeH3), 3.14 (d, 9H,
31
6.91 (t m, 2H, H5 þ H6 Ind), 6.61 (d, 2H, H4 þ H7 Ind), 5.26 (m, 1H,
CH3, JPH ¼ 12.0). P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA 162.4, dB
H2 Ind), 3.46 (d, 9H, CH3), 3.42 (s br, 2H, H1 þ H3 Ind) ppm. 31P{1H}
61.8, JAB ¼ 61.5. C26H32GeO3P2Ru (628.19): calcd. C 49.71, H 5.13;
NMR (CD2Cl2, 25 ꢁC)
d
: AB spin syst, dA 152.7, dB 49.0, JAB ¼ 75.3 Hz.
found C 49,58, H 5.26%.
Anal. Calcd for C30H31ClO3P2Ru (638.04): C, 56.47; H, 4.90; Cl, 5.56.
Found: C, 56.66; H, 4.81; Cl, 5.70%.
3b: IR (KBr pellet) nGeeH: 1915 (m br) cmꢀ1. 1H NMR (CD3C6D5,
25 ꢁC)
d
: 7.60, 7.29 and 7.02 (m, 15H, Ph), 4.52 (s, 5H, Cp), 3.69 and
L ¼ P(OEt)3: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.50e7.25 (m, 15H, Ph),
3.54 (m, 6H, CH2), ABX3, dx 3.26, JAx ¼ 3.1, JBx ¼ 1.3 (3H, GeH3), 0.98
31
6.85 (t m, 2H, H5 þ H6 Ind), 6.62 (d, 2H, H4 þ H7 Ind), 5.23 (m br,
1H, H2 Ind), 3.83 (m, 6H, CH2), 3.36 (s br, 2H, H1 þ H3 Ind), 1.10 (t,
(t, 9H, CH3). P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA 157.5, dB 61.6,
JAB ¼ 60.7. C29H38GeO3P2Ru (670.27): calcd. C 51.97, H 5.71; found C
9H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 147.5, dB 49.4,
52.14, H 5.80%.
JAB ¼ 76.5. Anal. Calcd for C33H37ClO3P2Ru (680.12): C, 58.28; H,
3c: IR (KBr pellet) nGeeH: 1945,1918 (m) cmꢀ1. 1H NMR (CD3C6D5,
5.48; Cl, 5.21. Found: C, 58.43; H, 5.37; Cl, 5.39%
25 ꢁC)
d: 7.38 and 7.01 (m, 20H, Ph), 4.37 (s, 5H, Cp), 3.87, 3.52 and
3.25 (m, 4H, CH2), ABX3, dx 3.30, JAx ¼ 2.95, JBx ¼ 1.6 (3H, GeH3), 1.14,
5-C9H7)(PPh3)L (2)
0.96 (t, 6H, CH3). P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA 175.4, dB
31
2.2.2. Ru(GeCl3)(Cp)(PPh3)L (1) and Ru(GeCl3)(
h
[L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c)]
58.8, JAB ¼ 47.3. C33H38GeO2P2Ru (702.31): calcd. C 56.44, H 5.45;
In a 25-mL three-necked round-bottomed flask were placed
found C 56.26, H 5.57%.
solid samples of the appropriate complex RuCl(Cp)(PPh3)L or
4a: IR (KBr pellet) nGeeH: 1921 (m br) cmꢀ1. 1H NMR (CD3C6D5,
RuCl(h
5-C9H7)(PPh3)L (1.3 mmol), an excess of GeCl2$dioxane
25 ꢁC)
d
: 7.25e6.95 (m, 15H, Ph), 6.84 (m, 2H, H5 þ H6 Ind), 6.42 (d,
(4.14 mmol, 0.96 g), and 10 mL of ethanol. The reaction mixture was
refluxed for 1 h and then the solvent was removed under reduced
pressure to give an oily product, which was triturated with ethanol
(2 mL). A yellow solid slowly separated out, which was filtered and
crystallised from CH2Cl2 and ethanol; yield 80%.
2H, H4 þ H7 Ind), 5.18 (m br,1H, H2 Ind), 4.88 (s br,1H, H3 Ind), 4.48
(s br, 1H, H1 Ind), ABX3, dx 3.21, JAx ¼ 3.7, JBx ¼ 0.6 (3H, GeH3), 3.18
(d, 9H, CH3). P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 159.2, dB 60.0,
31
JAB ¼ 55.0. C30H34GeO3P2Ru (678.25): calcd. C 53.13, H 5.05; found C
53.01, H 5.16%.
1a: 1H NMR (CD2Cl2, 25 ꢁC)
d
: 7.48e7.27 (m, 15H, Ph), 4.76 (s, 5H,
4b: IR (KBr pellet) nGeeH: 1931 (m br) cmꢀ1. 1H NMR (CD3C6D5,
Cp), 3.49 ppm (d, 9H, CH3, JPH ¼ 12.0 Hz). 31P{1H} NMR (CD2Cl2,
25 ꢁC)
d: 7.70e6.95 (m,15H, Ph), 7.83 (t m, 2H, H5 þ H6 Ind), 6.32 (d,

414
G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
2H, H4 þ H7 Ind), 5.24 (m,1H, H2 Ind), 4.90 (m,1H, H3 Ind), 4.47 (m,
1H, H1 Ind), 3.67 (m, 6H, CH2), ABX3, dx 3.22, JAx ¼ 3.7, JBx ¼ 0.95
filtration. Extracts were evaporated to dryness to give an oil which
was triturated with ethanol (2 mL). A yellow solid slowly separated
out, which was filtered and dried under vacuum; yield 35%.
8b: IR (KBr pellet) nBeH: 2454 (w); nGeeH: 1922 (m br) cmꢀ1. 1H
(3H, GeH3), 0.99 (t, 9H, CH3). 31P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA
153.3, dB 59.4, JAB ¼ 55.9. C33H40GeO3P2Ru (720.33): calcd. C 55.02,
H 5.60; found C 55.18, H 5.46%.
NMR (CD3C6D5, 25 ꢁC)
d
: 8.29e5.60 (m, 9H, Tp), 7.64e6.74 (m, 15H,
Ph), 3.38 and 3.30 (m, 6H, CH2), 3.32 (s, 3H, GeH3), 0.90 (t, 9H, CH3).
31P{1H} NMR (CD3C6D5, 25 ꢁC)
: AB, dA 147.4, dB 59.35, JAB ¼ 55.0.
33H43BGeN6O3P2Ru (818.20): calcd. C 48.44, H 5.30, N 10.27; found
C 48.28, H 5.42, N 10.11%.
8c: IR (KBr pellet) nBeH: 2459 (w), nGeeH: 1935,1915 (m) cmꢀ1. 1H
NMR (CD3C6D5, 25 ꢁC)
: 8.38e5.53 (m, 9H, Tp), 7.35e6.95 (m, 20H,
Ph), 3.78 and 3.40 (m, 4H, CH2), 3.23 (s, 3H, GeH3), 1.01 and 0.90 (t,
6H, CH3). 31P{1H} NMR (CD3C6D5, 25 ꢁC)
: AB, dA 182.4, dB 65.0,
2.2.4. Ru[Ge(OEt)3](Cp)(PPh3)L (5) and Ru[Ge(OEt)3](h5
C9H7)(PPh3)L (6) [L ¼ P(OEt)3 (b), PPh(OEt)2 (c)]
-
d
C
In a 50-mL three-necked round-bottomed flask were placed solid
samples of the appropriate complex Ru(GeCl3)(Cp)(PPh3)L (1) or
Ru(GeCl3)(
h
5-C9H7)(PPh3)L (2) (1.38 mmol), an excess of NaBH4
d
(8 mmol, 0.30 g), and 20 mL of ethanol. The reaction mixture was
stirred at room temperature for 30 min and then the solvent was
removed under reduced pressure. The solid obtained was extracted
with three 10-mL portions of toluene using a cellulose column for the
filtration. The extracts were evaporated to dryness to leave an oil
which was triturated with ethanol (3 mL). A yellow solid slowly
separated out, which was filtered and dried under vacuum; yield 65%.
d
JAB ¼ 46.2. C37H43BGeN6O2P2Ru (850.24): calcd. C 52.27, H 5.10, N
9.88; found C 52.43, H 5.20, N 9.74%.
2.2.7. Ru[Ge(OEt)3](Tp)(PPh3)[P(OEt)3] (9b)
In a 50-mL three-necked round-bottomed flask were placed
0.2 g (0.21 mmol) of the complex Ru(GeCl3)(Tp)(PPh3)[P(OEt)3]
(7b), an excess of NaBH4 (4.34 mmol, 0.16 g), and 20 mL of ethanol.
The reaction mixture was refluxed for 10 min and then the solvent
was removed under reduced pressure. The complex was extracted
from the solid obtained with three 10-mL portions of toluene using
a cellulose column (3 cm) for filtration. The extracts were evapo-
rated to dryness to give an oil which was triturated with ethanol
(2 mL). A yellow solid slowly separated out, which was filtered and
dried under vacuum; yield 40%.
5b: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.78, 7.07 (m, 15H, Ph), 4.70 (d, 5H,
Cp), 4.04 (m, 6H, CH2 phos), 3.82 and 3.63 (q, 6H, CH2 GeOEt), 1.27
and 1.24 (t, 9H, CH3 phos), 1.02 (t, 9H, CH3 GeOEt). 31P{1H} NMR
(CD2Cl2, 25 ꢁC)
d
: AB, dA 155.3, dB 58.1, JAB ¼ 60.5. C35H50GeO6P2Ru
(802.43): calcd. C 52.39, H 6.28; found C 52.21, H 6.16%.
5c: 1H NMR (CD3C6D5, 25 ꢁC)
: 7.40e6.98 (m, 20H, Ph), 4.61 (s,
d
5H, Cp), 4.24, 3.92, 3.66 and 3.41 (m, 4H, CH2 phos), 4.09 and 4.05
(q, 6H, CH2 GeOEt), 1.31 (t, 9H, CH3 GeOEt), 1.21 and 1.20 (t, 6H, CH3
phos). 31P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA 175.4, dB 55.4,
JAB ¼ 47.4. C39H50GeO5P2Ru (834.47): calcd. C 56.13, H 6.04; found C
IR (KBr pellet) nBeH: 2460 (w) cmꢀ1. 1H NMR (CD3C6D5, 25 ꢁC)
d:
9.10e5.50 (m, 9H, Tp), 7.32e6.98 (m, 15H, Ph), 3.89 and 3.81 (q, 6H,
56.31, H 5.93%.
6b: 1H NMR (CD2Cl2, 25 ꢁC)
d: 7.34e6.49 (m, 15H, Ph), 6.79 (t m,
CH2 GeOEt), 3.45 (m, 6H, CH2 phos), 1.24 (t, 9H, CH3 GeOEt), 0.97 (t,
2H, H5 þ H6 Ind), 6.04 (d, 2H, H4 þ H7 Ind), 5.88 (m, 1H, H2 Ind),
5.03 (s br, 1H, H3 Ind), 4.61 (br, 1H, H1 Ind), 3.85 (m, 6H, CH2 phos),
3.69 (q, 6H, CH2 GeOEt), 1.20 (t, 9H, CH3 GeOEt), 1.03 (t, 9H, CH3
9H, CH3 phos). 31P{1H} NMR (CD3C6D5, 25 ꢁC)
d: AB, dA 144.3, dB 57.1,
JAB ¼ 53.4. C39H55BGeN6O6P2Ru (950.36): calcd. C 49.29, H 5.83, N
8.84; found C 49.10, H 5.74, N 8.97%.
phos). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 150.6, dB 54.4,
JAB ¼ 53.5. C39H52GeO6P2Ru (852.48): calcd. C 54.95, H 6.15; found C
2.2.8. Os(GeCl3)(Tp)(PPh3)L (10) [L ¼ P(OMe)3 (a), P(OEt)3 (b),
PPh(OEt)2 (c)]
54.78, H 6.09%.
In a 50-mL three-necked round-bottomed flask were placed
solid samples of the complex OsCl(Tp)(PPh3)L (0.23 mmol), an
excess of GeCl2$dioxane (0.46 mmol, 107 mg), and 30 mL of 1,2-
dichloroethane. The reaction mixture was refluxed for 1 h and
then the solvent was removed under reduced pressure. The oil
obtained was triturated with ethanol (2 mL) until a white solid
separated out, which was filtered and crystallised from CH2Cl2 and
ethanol; yield 70%.
2.2.5. Ru(GeCl3)(Tp)(PPh3)L (7) [P ¼ P(OEt)3 (b), PPh(OEt)2 (c)]
In a 50-mL three-necked round-bottomed flask were placed
solid samples of the appropriate complex RuCl(Tp)(PPh3)L
(0.37 mmol), an excess of GeCl2$dioxane (1.1 mmol, 0.25 g), and
10 mL of ethanol. The reaction mixture was refluxed for 90 min and
the solvent was removed under reduced pressure to give a solid,
which was triturated with ethanol (2 mL), filtered and crystallised
from CH2Cl2 and ethanol; yield 65%.
10a: IR (KBr pellet) nBeH: 2482 (m) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢁC)
7b: IR (KBr pellet) nBeH: 2459 (w) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢁC)
d
: 8.24e5.62 (m, 9H, Tp), 7.31e7.18 (m, 15H, Ph), 3.33 (d, 9H, CH3).
31P{1H} NMR (CD2Cl2, 25 ꢁC)
: AB, dA 75.3, dB 8.9, JAB ¼ 30.3.
C30H34BCl3GeN6O3OsP2 (968.62): calcd. C 37.20, H 3.54, Cl 10.98, N
d
: 8.39e5.69 (m, 9H, Tp), 7.45e7.17 (m, 15H, Ph), 3.57 (m, 6H, CH2),
d
1.11 (t, 9H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 132.6, dB 51.8,
JAB ¼ 51.5. C33H40BCl3GeN6O3P2Ru (921.54): calcd. C 43.01, H 4.38,
Cl 11.54, N 9.12; found C 43.22, H 4.49, Cl 11.40, N 8.99%.
7c: IR (KBr pellet) nBeH: 2460 (w) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢁC)
8.68; found C 37.08, H 3.67, Cl 11.16, N 8.55%.
10b: IR (KBr pellet) nBeH: 2487 (m) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢁC)
d
: 8.40e5.56 (m, 9H, Tp), 7.65e7.16 (m, 15H, Ph), 3.56 (m, 6H, CH2),
d
: 7.95e5.41 (m, 9H, Tp), 7.38e6.98 (m, 20H, Ph), 4.95, 4.12 and 3.87
1.10 (t, 9H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
d: AB, dA 72.4, dB 7.7,
(m, 4H, CH2), 1.21 and 1.18 (t, 6H, CH3). 31P{1H} NMR (CD2Cl2, 25 ꢁC)
JAB ¼ 29.3. C33H40BCl3GeN6O3OsP2 (1010.70): calcd. C 39.22, H 3.99,
Cl 10.52, N 8.32; found C 30.39, H 4.10, Cl 10.38, N 8.44%.
10c: IR (KBr pellet) nBeH: 2482 (m) cmꢀ1. 1H NMR (CD2Cl2, 25 ꢁC)
d
: AB, dA 166.3, dB 52.45, JAB ¼ 47.0. C37H40BCl3GeN6O2P2Ru
(953.58): calcd. C 46.60, H 4.23, Cl 11.15, N 8.81; found C 46.42, H
4.35, Cl 11.01, N 8.94%.
d
: 8.27e5.64 (m, 9H, Tp), 7.48e7.20 (m, 20H, Ph), 4.36, 3.96, 3.67
and 3.28 (m, 4H, CH2), 1.37 and 1.10 (t, 6H, CH3). 31P{1H} NMR
(CD2Cl2, 25 ꢁC)
AB, dA 129.9, dB ꢀ2.23, JAB 24.3.
37H40BCl3GeN6O2OsP2 (1042.74): calcd. C 42.62, H 3.87, Cl 10.20, N
8.06; found C 42.47, H 3.76, Cl 10.33, N 7.95%.
2.2.6. Ru(GeH3)(Tp)(PPh3)L (8) [P ¼ P(OEt)3 (b), PPh(OEt)2 (c)]
In a 50-mL three-necked round-bottomed flask were placed solid
samples of the appropriate complex Ru(GeCl3)(Tp)(PPh3)L (7)
(0.21 mmol), an excess of LiAlH4 (4.2 mmol, 0.16 g), and 20 mL of THF.
The reaction mixture was stirred at room temperature for 80 min
and then the solvent was removed under reduced pressure giving a
brown solid. The complex was extracted from the solid with three
10-mL portions of toluene using a cellulose column (3 cm) for
d
:
¼
C
2.2.9. Os[Ge(OEt)3](Tp)(PPh3)L (11) [L ¼ P(OMe)3 (a), P(OEt)3 (b)]
An excess of NaBH4 (2.4 mmol, 91 mg) in ethanol (20 mL) was
added to a suspension of the appropriate Os(GeCl3)(Tp)(PPh3)L (10)
(0.12 mmol) in ethanol (10 mL) and the reaction mixture was

G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
415
Table 1
stirred at room temperature for 1 h. The solvent was removed
Crystal data and structure refinement for 3a.
under reduced pressure to give a solid from which the complex was
extracted with three 10-mL portions of toluene using a cellulose
column (3 cm) for filtration. The extracts were evaporated to dry-
ness 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 dried under vacuum; yield 55%.
Empirical formula
C26H32O3P2GeRu
Formula weight
Temperature
Wavelength
Crystal system
Space group
Unit cell dimensions
628.12
293(2) K
ꢀ
0.71073 A
Monoclinic
P21/c
11a: IR (KBr pellet) nBeH: 2464 (m) cmꢀ1
25 ꢁC)
: 8.82e5.51 (m, 9H, Tp), 7.59e7.00 (m, 15H, Ph), 3.84 (q) and
3.76 (q) (6H, CH2), 3.11 (d, 9H, CH3 phos),1.23 (t, 9H, CH3 GeOEt). 31
{1H} NMR (CD3C6D5, 25 ꢁC)
: AB, dA 86.3, dB 12.1, JAB ¼ 30.5.
36H49BGeN6O6OsP2 (997.44): calcd. C 43.35, H 4.95, N 8.43; found
C 43.43, H 5.07, N 8.30%.
11b: IR (KBr pellet) nBeH: 2459 (m) cmꢀ1
25 ꢁC)
: 9.19e5.45 (m, 9H, Tp), 7.63e6.97 (m, 15H, Ph), 3.90 (q) and
3.82 (q) (6H, CH2 GeOEt), 3.46 (m, 6H, CH2 phos), 1.24 (t, 9H, CH3
phos), 0.98 (t, 9H, CH3 GeOEt). 31P{1H} NMR (CD3C6D5, 25 ꢁC)
: AB,
.
1H NMR (CD3C6D5,
ꢀ
a ¼ 17.932(3) A
d
ꢀ
b ¼ 10.0667(14) A
ꢀ
P
c ¼ 16.375(2) A
b
¼ 114.508(2)ꢁ
d
3
ꢀ
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
2689.6(7) A
4
C
1.551 Mg/m3
1.823 mmꢀ1
1272
.
1H NMR (CD3C6D5,
d
Crystal size
0.33 ꢂ 0.12 ꢂ 0.10 mm
1.25e25.02ꢁ
ꢀ21 ꢃ h ꢃ 21
ꢀ11 ꢃ k ꢃ 11
ꢀ19 ꢃ l ꢃ 19
19,979
q
range for data collection
d
Index ranges
dA 82.8, dB 11.2, JAB ¼ 29.5. C39H55BGeN6O6OsP2 (1039.52): calcd. C
45.06, H 5.33, N 8.08; found C 44.92, H 5.24, N 8.21%.
Reflections collected
Independent reflections
Reflections observed (>2
Data Completeness
4742 [R(int) ¼ 0.0446]
2.2.10. Os(GeH3)(Tp)(PPh3)[P(OMe)3] (12a)
s
)
3330
In a 50-mL three-necked round-bottomed flask were placed a
solid sample of complex Os(GeCl3)(Tp)(PPh3)[P(OMe)3] (10a)
(100 mg, 0.1 mmol), an excess of NaBH4 (2 mmol, 76 mg), and 20 mL
of ethanol. The reaction mixture was refluxed for 30 min and then
the solvent was removed under reduced pressure. The complex was
extracted from the solid obtained with three 10-mL portions of
toluene using a cellulose column (3 cm) for filtration. Extracts were
evaporated to dryness and the oil obtained was triturated with
ethanol (2 mL). A white solid slowly separated out, which was
filtered and dried under vacuum; yield 40%.
0.999
Absorption correction
Max. and min. transmission
Refinement method
Semi-empirical from equivalents
0.7452 and 0.6609
Full-matrix least-squares on F2
4742/0/312
Data/restraints/parameters
Goodness-of-fit on F2
1.034
Final R indices [I > 2
s
(I)]
R1 ¼ 0.0489 wR2 ¼ 0.1201
R indices (all data)
Largest diff. peak and hole
R1 ¼ 0.0797 wR2 ¼ 0.1440
ꢀꢀ3
1.267 and ꢀ1.018 eA
IR (KBr pellet) nBeH: 2476 (m); nGeeH: 1955 (m br) cmꢀ1. 1H NMR
and RuCl(
in Scheme 1.
The reaction proceeded with the insertion of GeCl2 into the Rue
h
5-C9H7)(PPh3)L with GeCl2$dioxane in ethanol, as shown
(CD3C6D5, 25 ꢁC)
d
: 8.82e5.50 (m, 9H, Tp), 7.60e7.02 (m, 15H, Ph),
3.52 (dd br, 3H, GeH3), 3.11 (d br, 9H, CH3). 31P{1H} NMR (CD3C6D5,
25 ꢁC)
d
: AB, dA 88.75, dB 10.95, JAB ¼ 29.1. C30H37BGeN6O3OsP2
Cl bond to afford trichlorogermyl derivatives 1 and 2, which were
isolated in good yield and characterised.
(865.28): calcd. C 41.64, H 4.31, N 9.71; found C 41.78, H 4.19, N
9.62%.
Trichlorogermyl derivatives 1 and 2 were reacted with hydride-
transfer reagents such as LiAlH4 and NaBH4, to test whether sub-
stitution of the germanium-bonded chlorides with He would occur,
affording trihydridogermyl [Ru]eGeH3 derivatives. The results
showed that both Cp and indenyl complexes 1 and 2 react with
2.3. Crystal structure determination of Ru(GeH3)(Cp)(PPh3)
[P(OMe)3] (3a)
LiAlH4 in THF to yield hydridogermyl derivatives Ru(GeH3)(h5
-
Crystallographic data were collected on a Bruker Smart 1000
C5H5)(PPh3)L (3) and Ru(GeH3)(
separated in good yield and characterised (Scheme 2).
Surprisingly, the reaction of trichlorogermyl complexes 1 and 2
with NaBH4 in ethanol did not give trihydridogermyl complexes 3
and 4, but proceeded with the formation of triethoxygermyl
h
5-C9H7)(PPh3)L (4), which were
CCD diffractometer at CACTI (Universidade de Vigo) using graphite
ꢀ
monochromated Mo-K
a
radiation (
l
¼ 0.71073 A), and were cor-
rected for Lorentz and polarisation effects. The software SMART
[12] was used for collecting frames of data, indexing reflections, and
the determination of lattice parameters, SAINT [13] for integration
of intensity of reflections and scaling, and SADABS [14] for empirical
absorption correction. The crystallographic treatment of the com-
pounds was performed with the Oscail program [15]. The structures
were solved by direct methods and refined by a full-matrix least-
squares based on F2 [16]. Hydrogen atoms were included in ideal-
ised positions and refined, except those bound to the germanium
atoms, that were found in the electronic density map and refined
with isotropic displacement parameters. Details of crystal data and
structural refinement are given in Table 1.
exc. GeCl2•dioxane
Cl
Cl
Ru
Ru
Ph3P
Ph3P
EtOH
Cl
Ge
Cl
L
L
1
exc. GeCl2•dioxane
EtOH
3. Results and discussion
Cl
Cl
Ru
Ru
Ph3P
Ph3P
Cl
Ge
Cl
L
L
3.1. Cyclopentadienyl and indenyl complexes
Half-sandwich trichlorogermyl complexes of the types
2
Ru(GeCl3)(
h
5-C5H5)(PPh3)L (1) and Ru(GeCl3)(
h
5-C9H7)(PPh3)L (2)
5-C5H5)(PPh3)L
were prepared by reacting chloro complexes RuCl(
h
Scheme 1. L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c).

416
G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
C1
C3
C2
H1
Ge
C5
exc. LiAlH4
THF
Cl
Cl
H
Ru
Ru
Ph3P
Ph3P
H
Ge
Cl
Ge
H
L
L
C4
1
3
H3
Ru
exc. LiAlH4
THF
Cl
Cl
H
H2
Ru
Ru
Ph3P
Ph3P
H
Ge
Cl
Ge
H
L
L
P1
2
4
P2
Scheme 2. L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c).
Fig. 1. ORTEP view (30% probability level) of compound 3a. Only the hydrogen atoms
bonded to the germanium atom were drawn. [P1] represents a P(OMe)3 and [P2] a
PPh3.
derivatives Ru[Ge(OEt)3](
Et)3](
5-C9H7)(PPh3)L (6b), as shown in Scheme 3.
h
5-C5H5)(PPh3)L (5b, 5c) and Ru[Ge(O-
h
The reaction proceeded with apparent substitution of the three
Geebonded chlorides with OEte, giving triethoxygermyl derivatives
5b, 5c and 6b, which were isolated in good yield and characterised.
The formation of triethoxygermyl species in this reaction was not
completely unexpected, both because of the known oxophilic nature
of germanium [1e3], which forms stable OR and OH derivatives, and
the precedent of rhenium complexes Re[Ge(OEt)3](CO)nP5ꢀn [7].
However, we found that [Ru]eGeH3 species are very stable in
ethanol and that NaBH4 does not therefore produce [Ru]eGeH3 in
the reaction with [Ru]eGeCl3 complexes 1 and 2, but probably fa-
vours a different reaction of chlorogermyl with ethanol, yielding the
final [Ru]eGe(OEt)3 species 5b, 5c and 6b.
[Ru]eGeCl3 and [Ru]eGe(OEt)3 complexes, but also of the first
trihydridogermyl derivatives of ruthenium.
The new germyl complexes 1e6 were isolated as yellow (1e4) or
white (5, 6) solids, stable in air and in solution of common organic
solvents, where they behave as non-electrolytes. Their formulation
is supported by analytical and spectroscopic (IR, NMR) data and by
X-ray crystal structure determination of Ru(GeH3)(h
5-C5H5)(PPh3)
[P(OMe)3] (3a), the ORTEP of which is shown in Fig. 1.
The complex consists of a ruthenium atom in a half-sandwich
piano-stool structure, coordinated by
a h
5-cyclopentadienyl
ligand having one trihydridogermyl ligand and two phosphine li-
gands, one PPh3 and one P(OMe)3, as the legs. Selected bond
lengths and angles are shown in Table 2. The overall geometry of
the complex is well-known to be octahedral and is marked by near
90ꢁ values for angles PeRueP and GeeRueP, between 89.11(5) and
Comparison between the reactivity of known half-sandwich
stannyl complexes [Ru]eSnCl3 [11a] and our germyl complexes
[Ru]eGeCl3 towards group-13 tetrahydrides BHe4 and AlH4e can only
be made for cyclopentadienyl derivatives Ru(ECl3)(h
5-C5H5)(PPh3)L
95.98(7)ꢁ. The usual
Ruecentroid distance of 1.9056(5) A) shows RueC bond distances
between 2.230(7) and 2.263(7) A, the longer one corresponding to
h
5-coordination mode of the Cp ligand (with a
(E ¼ Sn, Ge), and highlights the fact that trihydrido species [Ru]e
EH3 were prepared with both Sn and Ge elements. However,
although tin trihydrido SnH3 was obtained only with NaBH4, the
preparation of trihydridogermyl GeH3 requires LiAlH4 as reagent in
the reaction of [Ru]eGeCl3. Instead, the reaction of trichlorogermyl
compounds with NaBH4 appears to be interesting, since it reveals a
new reaction by the GeCl3 ligand, affording triethoxygermyl de-
rivatives [Ru]eGe(OEt)3. It is worth noting that, although a number
of germyl complexes of Ru and Os have been reported in the
literature, none of them contains trihydridogermyl as ligand. The
ꢀ
ꢀ
that trans to the germyl ligand. These values are in the usual range
ꢀ
for RuCp moieties: for example, a RueCp distance of 1.889 A in
Ru(Cp)(SnClMe2)[P(OEt)3](PPh3) [11a]. The RueP bond distances
ꢀ
ꢀ
[2.193(2) A for RueP(OMe)3 and 2.294(2) A for RuePPh3] are also
similar to those previously found: for example, 2.2239(5) and
2.3113(4) in Ru(Cp)Cl[P(OMe)3](PPh3) [17]. The RueGe bond dis-
ꢀ
tance is 2.4421(9) A. To the best of our knowledge, there is no
use of mixed-ligand half-sandwich fragments Ru(
and Ru(
h
5-C5H5)(PPh3)L
h
5-C9H7)(PPh3)L allowed the easy preparation not only of
crystallographically characterised trihydridogermanium ligand
coordinated to a ruthenium atom, although other metal complexes
are known [18]. The CSD (Cambridge Structural Database) [19] was
used to find scarce mononuclear complexes of ruthenium with
terminal R3Ge ligands, but they show comparable values for this
exc. NaBH4
EtOH
Cl
Cl
OEt
OEt
Ru
Ru
Ph3P
L
Ph3P
Table 2
Ge
Cl
Ge
L
ꢁ
ꢀ
Selected bond lengths [A] and angles [ ] for 3a.
RueCT01
RueP(2)
RueC(1)
RueC(3)
RueC(5)
GeeH(2)
CT01eRueP(1)
CT01eRueGe
P(2)eRueGe
RueGeeH(1)
RueGeeH(3)
H(1)eGeeH(3)
1.9056(5)
2.2945(16)
2.232(7)
2.247(7)
2.242(7)
1.42(9)
125.46(5)
117.70(3)
89.11(5)
109(4)
RueP(1)
RueGe
RueC(2)
RueC(4)
GeeH(1)
GeeH(3)
CT01eRueP(2)
P(1)eRueGe
P(1)eRueP(2)
RueGeeH(2)
H(1)eGeeH(2)
H(2)eGeeH(3)
2.1933(19)
2.4421(9)
2.230(7)
2.263(7)
1.36(9)
1.71(12)
126.88(5)
91.50(6)
95.98(7)
116(4)
OEt
1
5
exc. NaBH4
EtOH
Cl
Cl
OEt
OEt
Ru
Ru
Ph3P
L
Ph3P
Ge
Cl
Ge
L
OEt
2
6
109(4)
98(5)
99(5)
122(5)
Scheme 3. L ¼ P(OEt)3 (b), PPh(OEt)2 (c).

G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
417
ꢀ
H
distance, i.e., R ¼ Cl, RueGe bond average of 2.44 A [20]; R ¼ Me,
ꢀ
RueGe bond distance of 2.4455(4) A [21]; R ¼ Ph, RueGe bond
B
ꢀ
ꢀ
distances of 2.5498(2) A to 2.5751(2) A [22].
N
N
N
The GeH3 moiety shows a tetrahedral arrangement, but the
limitations of X-ray diffractometry for hydrogen atoms in the
proximity of heavy metals is well-known, so these geometric pa-
rameters do not require further comment.
N
N
N
exc. LiAlH4
THF
H
Ru
H
Ph3P
H
Ge
H
The 1H NMR spectra of trichlorogermyl complexes
L
B
Ru(GeCl3)(h h
5-C5H5)(PPh3)L (1) and Ru(GeCl3)( 5-C9H7)(PPh3)L (2)
N
N
N
showed the signals characteristic of Cp or indenyl ligands and the
phosphine groups, whereas the 31P{1H} spectra were AB multiplets,
fitting the proposed formulation for the complexes.
N
8
N
N
Cl
Cl
Ru
H
The IR spectra of trihydridogermyl derivatives Ru(GeH3)(h5
-
Ph3P
Ge
Cl
L
C5H5)(PPh3)L (3) and Ru(GeH3)(h
5-C9H7)(PPh3)L (4) showed two
B
N
N
bands of medium intensity at 1949e1915 cmꢀ1, attributed to the
nGeH of the GeH3 group. However, the presence of this ligand was
confirmed by the 1H NMR spectra, which showed a doublet of
doublets at 3.30e3.21 ppm, simulated with the parameters re-
ported in the Experimental section and due to the resonance of the
GeH3 group. The multiplicity of signals is due to coupling with the
two non-equivalent 31P nuclei of the phosphines. The spectra also
N
N
7
N
N
exc. NaBH4
EtOH
OEt
OEt
Ru
Ph3P
Ge
L
OEt
show the signals of the h h
5-C5H5, 5-C9H7 and phosphine ligands;
9
the 31P NMR spectra appeared as AB multiplets, fitting the proposed
formulation.
Scheme 5. L ¼ P(OEt)3 (b), PPh(OEt)2 (c).
Besides the signals of the Cp, indenyl and phosphine ligands, the
1H NMR spectra of triethoxygermyl complexes Ru[Ge(OEt)3](h5
-
reaction of trichlorogermyl [Ru]eGeCl3 (7b, 7c) afforded triethox-
ygermyl derivatives Ru[Ge(OEt)3](Tp)(PPh3)L (9b), which were
isolated in good yield and characterised (Scheme 5).
C5H5)(PPh3)L (5b, 5c) and Ru[Ge(OEt)3](h
5-C9H7)(PPh3)L (6b)
showed one quartet at 4.09e3.63 ppm and one triplet at 1.31e
1.02 ppm, which were correlated with each other in a COSY
experiment and attributed to the ethoxy group of the Ge(OEt)3
ligand. The 31P NMR spectra appeared as AB multiplets, matching
the proposed formulation for the complexes.
These reactions on RueTp fragments are interesting, because
they allowed the preparation of the first germyl complexes stabi-
lised by tris(pyrazolyl)borate as supporting ligand. We therefore
extended these studies to the related OseTp derivatives, and found
that mixed-ligand chloro complexes with PPh3 and phosphites
OsCl(Tp)(PPh3)L did react with an excess of GeCl2$dioxane to give
trichlorogermyl derivatives Os(GeCl3)(Tp)(PPh3)L (10), as shown in
Scheme 6.
The reaction is similar to that of ruthenium, with insertion of
GeCl2 into the OseCl bond, yielding the [Os]eGeCl3 derivatives.
Surprisingly, different behaviour was shown by osmium com-
plex (10) towards the hydride agents LiAlH4 and NaBH4 with
respect to the related ruthenium derivative Ru(GeCl3)(Tp)(PPh3)L
(7b, 7c).
Schemes 7 and 8 summarise the results and show that only the
reaction with NaBH4 of complexes Os(GeCl3)(Tp)(PPh3)[P(OR)3]
(R ¼ Me, Et) gave stable and isolable germyl derivatives. In fact,
although the reaction of [Os]eGeCl3 (10) with LiAlH4 in THF did not
yield any species containing a germyl ligand (Scheme 7), the re-
action with NaBH4 depended on both the nature of the phosphite
ligand and the experimental conditions (Scheme 8). In particular,
trimethylphosphite complex Os(GeCl3)(Tp)(PPh3)[P(OMe)3] (10a)
reacted with NaBH4 in ethanol at room temperature to give the
triethoxygermyl derivative Os[Ge(OEt)3](Tp)(PPh3)[P(OMe)3] (11a),
3.2. Tris(pyrazolyl)borate complexes
The results obtained with half-sandwich cyclopentadienyl and
indenyl fragments prompted us to extend study to a comparable
ligand such as tris(pyrazolyl)borate (Tp), to test whether it too can
stabilise trihydridogermyl derivatives. Results showed that the
mixed-ligand chloro complexes RuCl(Tp)(PPh3)L did react with
GeCl2$dioxane to give trichlorogermyl derivatives Ru(GeCl3)(Tp)(P
Ph3)L (7), which were isolated in good yield and characterised
(Scheme 4).
Also in this case, the reaction proceeded with insertion of the
GeCl2 into the RueCl bond to afford trichlorogermyl derivative 7.
The reactivity of these [Ru]eGeCl3 compounds towards hydride-
transfer reagents such as LiAlH4 and NaBH4 were studied, and the
results showed that, like the related half-sandwich compounds 1
and 2, the reaction proceeded with both reagents, but only with
LiAlH4 in THF did trihydridogermyl complexes Ru(GeH3)(Tp)(PPh3)
L (8b, 8c) form (Scheme 5). Instead, with NaBH4 in ethanol, the
H
H
H
H
B
B
B
B
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
exc. GeCl2•dioxane
EtOH
exc. GeCl2•dioxane
ClCH2CH2Cl
Cl
Cl
Cl
Cl
Ru
Ru
Os
Os
Ph3P
Ph3P
Ph3P
Ph3P
Cl
Ge
Cl
Cl
Ge
Cl
L
L
L
L
7
10
Scheme 4. L ¼ P(OEt)3 (b), PPh(OEt)2 (c).
Scheme 6. L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c).

418
G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
H
These results were rather surprising, and indicated that the first
product of the reaction of [Os]eGeCl3 (10) with NaBH4 in ethanol is
triethoxygermyl derivative [Os]eGe(OEt)3 (11a, 11b) which, in the
case of P(OMe)3, can further react with NaBH4 to afford trihy-
dridogermyl [Os]eGeH3 (12a) as final product. Indeed, the trihy-
dridogermyl complex 12a was also formed by reacting [Os]eGe(OEt)3
(11a) with NaBH4 in refluxing ethanol. Comparison between the
properties of the germyl complexes of Ru and Os containing Tp as
supporting ligand also showed that the trihydridogermyl species
[M]eGeH3 forms much more easily with Ru thanwith Os, and that the
single species of the latter, Os(GeH3)(Tp)(PPh3)[P(OMe)3] (12a), can
only be obtained with P(OMe)3 in the reaction with NaBH4.
B
N
N
N
N
N
N
LiAlH4
THF
Cl
Cl
decomposition products
Os
Ph3P
Ge
Cl
L
10
Scheme 7. L ¼ P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c).
The reluctance of osmium to give stable GeH3 derivatives was
also shown by the reaction of trichlorogermyl compounds [M]e
GeCl3 with LiAlH4 which, in all conditions, gave decomposition
products with osmium, although stable trihydridogermyl de-
rivatives [M]eGeH3 were obtained in the case of ruthenium. The
only property common to both metals was the easy formation of
the triethoxygermyl derivative [M]eGe(OEt)3, which could be ob-
tained with both P(OEt)3 and P(OMe)3 ligands.
whereas the trihydridogermyl derivative Os(GeH3)(Tp)(PPh3)
[P(OMe)3] (12a) formed in refluxing conditions. Conversely, the
related triethylphosphite complex Os(GeCl3)(Tp)(PPh3)[P(OEt)3]
(10b) in any conditions, i.e., at room temperature or refluxing,
exclusively gave the triethoxygermyl derivative Os[Ge(O-
Et)3](Tp)(PPh3)[P(OEt)3] (11b) in the reaction with NaBH4 in
ethanol. Lastly, only decomposition products were obtained from
the same reaction of Os(GeCl3)(Tp)(PPh3)[PPh(OEt)2] (10c).
All germyl complexes stabilised by the Tp ligand
e
M(GeCl3)(Tp)(PPh3)L (7, 10), M[Ge(OEt)3](Tp)(PPh3)L (9, 11) and
M(GeH3)(Tp)(PPh3)L (8, 12) e were isolated as white or pale-yellow
solids, stable in air and in solution of common organic solvents,
where they behave as non-electrolytes. Their formulations were
confirmed by analytical data, mainly chlorine for [M]eGeCl3 spe-
cies, and by infrared and NMR spectra.
In particular, the IR spectra of trichlorogermyl complexes
M(GeCl3)(Tp)(PPh3)L (7, 10) showed a medium-intensity band at
2460e2440 cmꢀ1, attributed to the nBH of the Tp ligand, the pres-
ence of which was further confirmed by 1H NMR spectra, which
showed the characteristic signals of the hydrogen atoms of the
pyrazolate group. In the proton spectra, the resonances associated
with the phosphine ligands also appeared, whereas the 31P spectra
showed an AB quartet, indicating the presence of two magnetically
non-equivalent phosphorus nuclei, matching the proposed
formulation for the compounds.
The IR spectra of trihydridogermyl complexes M(GeH3)(T
p)(PPh3)L (8, 12) (M ¼ Ru 8, Os 12) showed not only the absorption
of supporting ligands but also two medium-intensity bands at
1955e1915 cmꢀ1, attributed to the nGeH of the GeH3 group. How-
ever, support for the presence of the trihydridogermyl ligand came
from the 1H NMR spectra, which showed a slightly broad singlet at
3.32e3.23 ppm for 8 and 3.52 ppm for 12a, due to coupling of the
germyl hydrides with the phosphorus nuclei of the phosphines. The
31P NMR spectra were AB multiplets, fitting the proposed formu-
lations for the complexes.
H
B
N
N
N
N
N
[Os] =
N
Os
Ph3P
L
NaBH4
OEt
OEt
[Os]
EtOH, R.T.
Ge
NaBH4
EtOH
reflux
OEt
Cl
Cl
[Os]
11a
Ge
Cl
NaBH4
H
H
[Os]
[Os]
10a
EtOH, reflux
Ge
H
L = P(OMe)3
12a
NaBH4, EtOH
Cl
Cl
OEt
OEt
The 1H NMR spectra of triethoxygermyl derivatives M[Ge(O-
Et)3](Tp)(PPh3)L (9, 11) showed not only the signals of the Tp, PPh3
and phosphite supporting ligands but also a quartet between 3.90
and 3.76 ppm and a triplet at 1.23e1.24 ppm, attributed to the
ethoxy groups of the Ge(OEt)3 ligand. This attribution was sup-
ported by a COSY experiment, which showed a correlation between
methylene and the methyl protons of the OCH2CH3 groups. For all
triethoxygermyl complexes 9, 11, the 31P NMR spectra appeared as
AB multiplets, matching the proposed formulation.
[Os]
Ge
R.T. and reflux
Ge
Cl
OEt
10b
11b
L = P(OEt)3
NaBH4
Cl
Cl
decomposition products
[Os]
Ge
4. Conclusions
EtOH, R.T.
This paper reports that both half-sandwich fragments with
cyclopentadienyl and indenyl ligands Ru(h
5-C5H5)(PPh3)L and
Cl
Ru(
h
5-C9H7)(PPh3)L (L ¼ phosphite) can stabilise trichlorogermyl
10c
complexes [Ru]eGeCl3. Their reaction with group 13 hydrides,
which afforded trihydridogermyl derivatives [Ru]eGeH3 with
LiAlH4, was interesting, whereas triethoxygermyl complexes [Ru]e
L = PPh(OEt)2
Scheme 8.

G. Albertin et al. / Journal of Organometallic Chemistry 751 (2014) 412e419
419
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azolylborate) ligand (Tp) can also stabilise trichlorogermyl de-
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which with LiAlH4 and NaBH4 allowed both trihydridogermyl
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The financial support of MIUR (Rome) - PRIN 2009 is gratefully
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Appendix A. Supplementary material
CCDC 941586 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.
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