The solid-state, solution and gas-phase interactions of diphosphane monooxide spacers with heavier group 8,9 transition metals and gallium in novel organometallic assemblies: An experimental and computational study

Article abstract of DOI:10.1016/j.jorganchem.2012.03.003

Six new mono-substituted carbonyl clusters [M₃(CO) ₁₁(DPMO)] (M = Os, Ru; 1-4) and [Rh₆(CO) ₁₅(DPMO)] (5, 6) were obtained from the reactions of non-symmetrical bifunctional diphosphane monoxides (DPMOs, Ph₂P(CH₂) _nP(O)Ph₂, n = 2, 3) with triangular clusters [Os ₃(CO)₁₂] and [Ru₃(CO)₁₂], and octahedral cluster [Rh₆(CO)₁₅(NCMe)] under mild conditions. 1-6 were then subjected to electrophilic reactions with GaCl ₃, which resulted in coordination-based molecular assemblies [M ₃(CO)₁₁(DPMO)(GaCl₃)] (M = Ru, Os; 7-10) and [Rh₆(CO)₁₅(DPMO)(GaCl₃)] (11, 12). 1-12 were characterised by ³¹P{¹H} NMR, IR spectroscopy, and FAB mass spectrometry. The crystal structures of 1, 2 and 7 were determined by single-crystal X-ray analysis. 7 is the first solid-state characterised Os-Ga bridged complex. The latter and its constitutive fragment, 1, were studied by density functional calculations in the gas phase and in solution in order to better understand their structural features. Two different rotameric structures related by rotation about the P-C-C-P linkage of the DPMO ligand were established for 1 and 7. The bonding properties of 7 were analysed by means of a quantitative energy decomposition analysis (EDA). The EDA revealed a predominant electrostatic character for the interactions between the three units (carbonyl cluster, gallium halide and spacer) constitutive of 7.

Full text of DOI:10.1016/j.jorganchem.2012.03.003

Journal of Organometallic Chemistry 714 (2012) 22e31
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
The solid-state, solution and gasephase interactions of diphosphane monooxide
spacers with heavier group 8,9 transition metals and gallium in novel
organometallic assemblies: An experimental and computational study
, ,
,
b
a
a
Kirill Yu. Monakhov a 1, Elena V. Grachova b , Galina L. Starova , Thomas Zessin , Gerald Linti
*
*
a Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
b Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
Six new mono-substituted carbonyl clusters [M3(CO)11(DPMO)] (M
¼
Os, Ru; 1e4) and
Received 10 December 2011
Received in revised form
22 February 2012
[Rh6(CO)15(DPMO)] (5, 6) were obtained from the reactions of non-symmetrical bifunctional diphos-
phane monoxides (DPMOs, Ph2P(CH2)nP(O)Ph2, n ¼ 2, 3) with triangular clusters [Os3(CO)12] and
[Ru3(CO)12], and octahedral cluster [Rh6(CO)15(NCMe)] under mild conditions. 1e6 were then subjected
to electrophilic reactions with GaCl3, which resulted in coordination-based molecular assemblies
[M3(CO)11(DPMO)(GaCl3)] (M ¼ Ru, Os; 7e10) and [Rh6(CO)15(DPMO)(GaCl3)] (11, 12). 1e12 were char-
acterised by 31P{1H} NMR, IR spectroscopy, and FAB mass spectrometry. The crystal structures of 1, 2 and
7 were determined by single-crystal X-ray analysis. 7 is the first solid-state characterised OseGa bridged
complex. The latter and its constitutive fragment, 1, were studied by density functional calculations in the
gas phase and in solution in order to better understand their structural features. Two different rotameric
structures related by rotation about the PeCeCeP linkage of the DPMO ligand were established for 1 and
7. The bonding properties of 7 were analysed by means of a quantitative energy decomposition analysis
(EDA). The EDA revealed a predominant electrostatic character for the interactions between the three
units (carbonyl cluster, gallium halide and spacer) constitutive of 7.
Accepted 3 March 2012
Keywords:
Transition metals
Gallium
Spacer
Crystal structures
Density functional calculations
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
definite size, chemical properties, and structural features of tran-
sition metal (TM) carbonyl clusters give the possibility to use the
Coordination-based molecular assemblies with well-defined
composition, specific properties and structures containing both main
group elements and transition metals in different oxidation states
attract considerable attention stimulated by purely academic and
practical reasons. Their synthesis, structural characterisation and
studies at the computational level are of high current interest in diverse
branches of chemical science. Herein, we focus on organometallic
complexes in which bridging ligands link metal centres of dramatically
different nature. Such assemblies seem to have a good chance to
display unusual physicochemical properties, catalytic properties [1]
and to be precursors to a wide range of hybrid materials [2].
latter as versatile building blocks for the synthesis of complicated
macromolecules [3] and metal nanoparticles [4]. The Lewis acidic
main group metal salt can form coordination complexes with
electron-rich ligands. In its turn, an organic linker (or spacer) with
two coordination sites at the beginning and at the end of the ligand
chain makes use of the opportunity to link metal centres of two
different species. Thus, molecular architectures can be constructed
by design of such a relevant spacer.
The aim of this work is to explore new coordination-based
molecular assemblies based on non-symmetrical bifunctional
phosphanes DPMOs of the type Ph2P(CH2)nP(O)Ph2 (n ¼ 2, 3) linking
low-nuclear carbonyl clusters of the heavier group 8 and 9 transition
metals (Ru, Os and Rh), namely [M3(CO)12] (M ¼ Ru, Os) and
[M6(CO)16] (M ¼ Rh) and the group 13 element halide, GaCl3. The
choice of the spacers was dictated by the nature of both hetero-
metallic centres. While the soft phosphane P-donors are usually
bonded to the d-metals, the hard phosphane oxide O-donors are
ideal to connect the group 13 metals [5e7].
What types of constitutive molecular units were used to fabri-
cate novel multifunctional coordination-based assemblies? The
* Corresponding authors. Tel.: þ7 (812) 428 4028; fax: þ7 (812) 428 6939.
E-mail addresses: monakhov@unistra.fr (K.Yu. Monakhov), bird231102@mail.ru
(E.V. Grachova).
1
Present address: Laboratoire de Chimie de Coordination, Institut de Chimie
It is also noteworthy that the structural chemistry of the
(UMR 7177 CNRS), Université de Strasbourg, 4 Rue Blaise Pascal, CS 90032, F-67081
Strasbourg Cedex, France.
organometallic TMVIIIeGa (TM ¼ Ru, Os) and TMIxeGa (TM ¼ Rh, Ir)
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2012.03.003

K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
23
mixed complexes is still not well developed. The experimental
studies of the reactivity between the complexes of gallium and the
heavier group 8 (Ru, Os) and 9 (Rh, Ir) transition metals mainly
focus on the molecular RuGa and RhGa systems, respectively 31 and
36 crystal structures which are available in the Cambridge Crys-
tallographic Data Centre, CCDC. The number of the crystal struc-
tures reported e.g. for the mixed IrGa complexes is much smaller
with only 5 crystal structures. Concerning mixed-metal OsGa
complexes, no synthesis or structural data are available up to now,
nevertheless some theoretical works appeared [8]. Therefore, one
of the main goals of our work was to synthesise and structurally
characterise the first organometallic OsGa complex and to gain an
insight into the nature of its metaleligand interactions using the
combination of experimental and computational tools.
ray structure determination were grown from a dichloroethane/
acetone/octane mixture at þ4 ꢂC.
2.2.2. [Os3(CO)11(POPP)], 2
Yield 78%. IR (CH2Cl2, cmꢁ1
, nCO) 2106m, 2054s, 2032sh, 2017vs,
1987m, 1974sh, 1950sh. 31P{1H} NMR (
d
ppm, RT) ꢁ9.5 (d, 4JPeP ¼ 2,
1P, PeOs), 31.8 (broad s, 1P, P]O). MS (FAB, m/z) 1308 (Mþ)
C38H26O12Os3P2, the signals (MþenCO), n ¼ 1e8 were observed in
the spectrum. Anal. calcd for C38H26O12Os3P2: C, 34.91; H, 2.00.
Found: C, 34.87; H, 2.05. Single crystals of 2 suitable for X-ray
structure determination were grown from
a CH2Cl2/acetone/
heptane mixture at þ4 ꢂC.
2.2.3. [Ru3(CO)11(POPE)], 3
Yield 49%. IR (CH2Cl2, cmꢁ1
, nCO) 2097m, 2046s, 2028sh, 2013vs,
2. Experimental
1985sh. 31P{1H} NMR (
d
ppm, RT) 30.2 (d, 3JPeP ¼ 45, 1P, PeRu), 31.3
(d, 3JPeP ¼ 45, 1P, P]O). MS (FAB, m/z) 1343 (Mþ) C37H24O12P2Ru3,
the signals (MþenCO), n ¼ 1e9 were observed in the spectrum. Anal.
calcd for C37H24O12P2Ru3: C, 43.32; H, 2.36. Found: C, 43.46; H, 2.57.
2.1. General Comments
All synthetic procedures were carried out under an atmosphere
of dry argon using standard Schlenk techniques. All solvents were
distilled under inert atmosphere over appropriate drying agents
prior to use, and toluene was additionally stored over molecular
sieve A4 during one week. The [Rh6(CO)15(NCMe)] cluster [9] was
synthesised according to the literature procedure. Commercial
grade [Ru3(CO)12], [Os3(CO)12] (Aldrich); 1,2-Bis(diphenylphosp
hino)ethane monooxide, POPE and 1,3-Bis(diphenylphosphino)
propane monooxide, POPP (ABCR GmbH & Co. KG) were used
without further purification. Me3NO ꢀ 2H2O (Aldrich) was dehy-
drated in vacuo immediately before using. GaCl3 (Aldrich) was
sublimed immediately before using and packed in a glass capillary.
Infrared spectra were recorded using Perkin Elmer 16PC FT-IR
spectrometer. 31P{1H} NMR spectra were recorded in CDCl3 at
room temperature using Bruker ACD-HD AV400 and AV600
instruments. The chemical shifts were referenced to the resonance
in 85% H3PO4 aqua solution. Elemental analysis was carried out in
the Microanalytical Laboratory of the University of Heidelberg. FABþ
mass spectra were obtained on a JEOL JMS-700 instrument, Institute
of Organic Chemistry, University of Heidelberg.1-nitro-2-(octyloxy)
benzene was used as the matrix. Theoretical isotope patterns were
calculated using Sheffield ChemPuter program available free of
charge online http://winter.group.shef.ac.uk/chemputer/.
2.2.4. [Ru3(CO)11(POPP)], 4
Yield 37%. IR (CH2Cl2, cmꢁ1
, nCO) 2097m, 2046s, 2028sh, 2013vs,
1985sh. 31P{1H} NMR (
d
ppm, RT) 26.8 (d, 4JPeP ¼ 2, 1P, PeRu), 31.4
(d, 4JPeP ¼ 2,1P, P]O). MS (FAB, m/z) 1040 (Mþ) C38H26O12P2Ru3, the
signals (MþenCO), n ¼ 1e10 were observed in the spectrum. Anal.
calcd for C38H26O12P2Ru3: C, 43.90; H, 2.52. Found: C, 43.88; H, 2.61.
2.3. Synthesis of 5 and 6
The complex [Rh6(CO)15(NCMe)] (0.039 mmol) was dissolved in
CH2Cl2 (40 mL) and the solid POPE or POPP ligand (0.048 mmol)
was added under vigorous stirring. The reaction mixture immedi-
ately got a dark-red colour. After stirring for 15 min n-hexane was
added to the reaction mixture and the solvents were removed in
vacuo leaving dry brown material. The latter was dissolved in
a minimum volume of CH2Cl2 and the product was separated on
TLC silica plate with the CH2Cl2/n-hexane/acetone ¼ 30/30/15
mixture as an eluent and then washed out from silica with acetone.
Heptane was added to the acetone solution and the solvents were
removed in vacuo leaving brown crystalline precipitate of the
product.
2.3.1. [Rh6(CO)15(POPE)], 5
2.2. Synthesis of 1e4
Yield 59%. IR (CH2Cl2, cmꢁ1
, nCO) 2100m, 2065vs, 2035m, 2025sh,
2008sh, 1793brm. 31P{1H} NMR (
d
ppm, RT) 21.2 (ddm, 1JRheP ¼ 135,
2
3
The solution of fresh sublimed Me3NO (9 mg, 0.120 mmol) in an
ethanol/CH2Cl2 mixture (10 mL) was added dropwise during 0.5 h
to a solution of the [M3(CO)12] (M ¼ Os, Ru) cluster (0.110 mmol)
and the POPE or POPP ligand (0.175 mmol) in CH2Cl2 (100 mL) at
room temperature under vigorous stirring. After reaction
completed, the solvents were removed in vacuo leaving yellow (for
osmium) or orange (for ruthenium) oily material that was dissolved
in a minimum volume of CH2Cl2 and separated out on the silica
plate with the CH2Cl2/n-hexane/acetone ¼ 40/40/15 mixture as an
eluent. After the product was washed out from silica with acetone
and diluted with heptane. The solvents were removed in vacuo
leaving dry crystalline material.
3JPeP ¼ 38, JRheP ¼ 4, 1P, PeRh), 30.6 (d, JPeP ¼ 38, 1P, P]O). MS
(FAB, m/z) 1452 (Mþ) C41H24O16P2Rh6, the signals (MþenCO),
n
¼
1e14 were observed in the spectrum. Anal. calcd for
C41H24O16P2Rh6: C, 33.91; H, 1.67. Found: C, 33.97; H, 2.01.
2.3.2. [Rh6(CO)15(POPP)], 6
Yield 59%. IR (CH2Cl2, cmꢁ1
, nCO) 2100m, 2065vs, 2034m, 2024sh,
2008sh, 1793brm. 31P{1H} NMR (
d
ppm, RT) 18.2 (dm, 1JRheP ¼ 134,
2JRheP ¼ 3, 1P, PeRh), 31.5 (s, 1P, P]O). MS (FAB, m/z) 1466 (Mþ)
C42H26O16P2Rh6, the signals (MþenCO), n ¼ 1e14 were observed in
the spectrum. Anal. calcd for C42H26O16P2Rh6: C, 34.41; H, 1.79.
Found: C, 34.50; H, 1.99.
2.2.1. [Os3(CO)11(POPE)], 1
2.4. Synthesis of 7e10
Yield 79%. IR (CH2Cl2, cmꢁ1
, nCO) 2107m, 2055s, 2031sh, 2018vs,
1987m, 1977sh, 1950sh. 31P{1H} NMR (
d
ppm, RT) ꢁ6.9 (d,
In a typical procedure, complex 1e4 (0.043 mmol) was dissolved
in toluene and cooled in dry ice/isopropanol bath. The tube with
GaCl3 (ca 0.057 mmol) was then broken inside of the reaction flask
in the argon stream and under high stirring. After stirring for 1 h
the reaction mixture was allowed to warm to room temperature,
3JPeP ¼ 48, 1P, PeOs), 30.6 (d, JPeP ¼ 48, 1P, P]O). MS (FAB, m/z)
1294 (Mþ) C37H24O12Os3P2, the signals (MþenCO), n ¼ 1e10 were
observed in the spectrum. Anal. calcd for C37H24O12Os3P2: C, 34.36;
H, 1.87. Found: C, 34.47; H, 2.01. Single crystals of 1 suitable for X-
3

24
K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
and the solvent was removed in vacuo to give an oily material that
was washed by hexane and dried in vacuo. Resulting substance was
dissolved in CH2Cl2 and passed through short silica column using
the CH2Cl2/n-hexane/acetone ¼ 40/40/15 mixture as an eluent.
Heptane was added to the solution and the solvents were removed
in vacuo resulting in the formation of light orange (for ruthenium)
or yellow (for osmium) wax material. Satisfactory elemental anal-
ysis results and yield values (the yields of 7e12 are estimated as
75e80%) for 7e12 were not obtained because of an unremovable
admixture of gallium compounds.
2JRheP ¼ 3, 1P, PeRh), 55.4 (s, 1P, P]O). MS (FAB, m/z) 1642 (Mþ)
C42H26Cl3GaO16P2Rh6, the signals (MþenCO), n ¼ 1e14 were
observed in the spectrum.
2.6. X-ray crystal structure determination
Single crystals of compounds 1, 2, and 7 suitable for X-ray
diffraction studies were mounted with perfluorinated polyether oil
on the tip of a glass fibre and cooled down to 200 K immediately on
the goniometer head. Data collection was performed on a STOE
IPDS I diffractometer with Mo-K
a
radiation (
l
¼ 0.71073 Å).
2.4.1. [Os3(CO)11(POPE)(GaCl3)], 7
Structures were solved and refined with the Bruker AXS SHELXTL
5.1 program package. Refinement was in full matrix against F2. All
hydrogen atoms were included as riding models with fixed
isotropic U values in the final refinement. Due to the rather small
size and low quality of the crystals of 1 only Os and P atoms were
refined anisotropically. C(1)O(1) carbonyl ligand in the structure of
1 is disordered over two crystallographically non-equivalent half-
occupied positions with the total site-occupation factor (s.o.f.)
equal to 1.0. There is also a partial disordering in the C(20)eC(25)
ring. Thus, three carbon atoms C(23), C(24) and C(25) of the ring
disordered over two non-equivalent half-occupied positions with
the total s.o.f. equal to 1.0. In the structure of 7 there is the H[GaCl4]
complex. Crystal structure of 7 also contains crystallographically
disordered over two non-equivalent positions CHCl3 molecule with
the s.o.f. equal 0.50 and 0.25 for C(A)Cl(A)Cl(C)Cl(D) and C(B)Cl(B)
Cl(E)Cl(F) parts, respectively. For further data refer to Table 1.
IR (CH2Cl2, cmꢁ1
, nCO) 2150m, 2122w, 2107s, 2083s, 2066vs,
2046m, 2025s. 31P{1H} NMR (
d
ppm, RT) ꢁ12.0 (d, JPeP ¼ 44, 1P,
3
3
PeOs), 52.6 (d, JPeP ¼ 44, 1P, P]O). MS (FAB, m/z) 1470 (Mþ)
C37H24Cl3GaO12Os3P2, the signals (MþenCO),
n
¼
1e6 were
observed in the spectrum. Single crystals of 7 suitable for X-ray
structure determination were grown in a NMR tube from CDCl3
solution at þ4 ꢂC.
2.4.2. [Os3(CO)11(POPP)(GaCl3)], 8
IR (CH2Cl2, cmꢁ1
, nCO) 2149m, 2121w, 2106s, 2081s, 2064vs,
2043s, 2025s. 31P{1H} NMR (
d
ppm, RT) ꢁ13.3 (d, JPeP ¼ 4, 1P,
4
4
PeOs), 53.4 (d, JPeP ¼ 4, 1P, P]O). MS (FAB, m/z) 1484 (Mþ)
C38H26Cl3GaO12Os3P2, the signals (MþenCO),
n
¼
1e5 were
observed in the spectrum.
2.4.3. [Ru3(CO)11(POPE)(GaCl3)], 9
IR (CH2Cl2, cmꢁ1
, nCO) 2143m, 2130sh, 2104s, 2081s, 2067vs,
2.7. Computational details
2052vs, 2034s, 1974w. 31P{1H} NMR (
d
ppm, RT) 22.4 (d, 3JPeP ¼ 40,
3
1P, PeRu), 52.9 (d, JPeP ¼ 40, 1P, P]O). MS (FAB, m/z), 1201 (Mþ)
C37H24Cl3Ga1O12P2Ru3; the signals (MþenCO), n ¼ 1e8 were
observed in the spectrum.
Density functional theory (DFT) geometry optimisations were
firstly performed in the gas phase using the Gaussian 09 program
Table 1
2.4.4. [Ru3(CO)11(POPP)(GaCl3)], 10
Crystal data and structure refinement details for 1, 2, and 7.
IR (CH2Cl2, cmꢁ1
, nCO) 2143w, 2130sh, 2103s, 2080s, 2065vs,
1
2
7
2052sh, 2031s, 1975vw. 31P{1H} NMR (
d
ppm, RT) 20.4 (d, 4JPeP ¼ 4,
Empirical formula
C37H24O12Os3P2
C38H26O12Os3P2
C37.75H24Cl9.25
Ga2O12Os3P2
1769.46
Monoclinic
P 21/n
9.6141(19)
19.213(4)
29.691(6)
90.00
91.23(3)
90.00
5483.1(19)
4
4
1P, PeRu), 53.5 (d, JPeP ¼ 4, 1P, P]O). MS (FAB, m/z) 1216 (Mþ)
C38H26Cl3Ga1O12P2Ru3, the signals (MþenCO), n ¼ 1e6 were
observed in the spectrum.
Formula mass [g/mol]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
1293.10
Triclinic
P ꢁ1
1307.13
Monoclinic
P 21/c
15.244(3)
22.996(5)
11.348(2)
90.00
101.92(3)
90.00
3892.3(13)
4
8.7588(18)
13.607(3)
16.869(3)
77.96(3)
83.60(3)
73.75(3)
1884.7(7)
2
2.5. Synthesis of 11 and 12
a
b
g
[ꢂ]
[ꢂ]
[ꢂ]
In a typical procedure, complex 5 or 6 (0.021 mmol) was dis-
solved in ca. 20 mL of toluene and the tube with the GaCl3 (ca.
0.057 mmol) was broken inside of the reaction flask under high
stirring. After stirring for 1 h all volatile components were removed
in vacuo to result in brown oil. This substance was dissolved in
CHCl3 and passed through silica column using the CH2Cl2/n-
hexane/acetone ¼ 40/40/15 mixture as an eluent leaving some
brown start. Heptane was added to the solution and the solvents
were removed in vacuo, resulting in the formation of brown wax
substance. The latter was washed by hexane and then dried in
vacuo leaving brown paste material.
V [Å3]
Z
Calculated density
2.279
2.231
2.144
[g/cm3]
F(000) [e]
Crystal size [mm3]
1200
2432
3295
0.18 ꢀ 0.08
0.246 ꢀ 0.038
0.24 ꢀ 0.23
ꢀ 0.07
ꢀ 0.034
ꢀ 0.15
q
range for data
collection [ꢂ]
5.84 O 26.37
1.77 O 24.21
2.12 O 24.00
Index ranges
ꢁ10 ꢃ h ꢃ 10
ꢁ17 ꢃ k ꢃ 17
ꢁ21 ꢃ l ꢃ 21
15 505
7082
7082/88/263
ꢁ17 ꢃ h ꢃ 17
ꢁ26 ꢃ k ꢃ 26
ꢁ13 ꢃ l ꢃ 13
25 262
6229
6229/108/496
ꢁ11 ꢃ h ꢃ 11
ꢁ21 ꢃ k ꢃ 21
ꢁ33 ꢃ l ꢃ 32
34 949
8535
8535/6/601
2.5.1. [Rh6(CO)15(POPE)(GaCl3)], 11
Collected reflections
Unique reflections
Data/restraints/
parameters
IR (CH2Cl2, cmꢁ1
, nCO) 2101m, 2090w, 2066vs, 2035m, 2008sh,
1796brm. 31P{1H} NMR (
d
ppm, RT) 19.8 (ddm, JRheP ¼ 133,
1
3JPeP ¼ 39, JRheP ¼ 4, 1P, PeRh), 53.9 (d, JPeP ¼ 39, 1P, P]O). MS
(FAB, m/z) 1628 (Mþ) C41H24Cl3GaO16P2Rh6, the signals (MþenCO),
n ¼ 3e14 were observed in the spectrum.
2
3
Goodness of fit on F2
Final R indices
0.938
0.890
0.903
R1 ¼ 0.0709
wR2 ¼ 0.1553
R1 ¼ 0.1462
wR2 ¼ 0.1832
1.919/ꢁ2.818
R1 ¼ 0.0641
wR2 ¼ 0.1214
R1 ¼ 0.1552
wR2 ¼ 0.1423
2.034/ꢁ4.596
R1 ¼ 0.0470
wR2 ¼ 0.0870
R1 ¼ 0.0663
wR2 ¼ 0.0926
1.327/ꢁ0.960
(I > 2s(I))
R indices (all data)
2.5.2. [Rh6(CO)15(POPP)(GaCl3)], 12
IR (CH2Cl2, cmꢁ1
, nCO) 2100m, 2089w, 2065vs, 2035m, 2026sh,
Residual electronic
density, [e/Å3]
2006sh, 1795brm. 31P{1H} NMR (
d
ppm, RT) 17.9 (dm, 1JRheP ¼ 129,

K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
25
package [10] and energy minima were verified to be equilibrium
3. Results and discussion
structures through vibrational analysis. The equilibrium structures
were obtained from the DFT computations using the three-
parameter exchange functional of Becke [11] with gradient-
corrected correlation functional of Lee, Yang, and Parr (B3LYP)
[12]. We used Los Alamos National Laboratory 2 (LANL2) relativistic
effective core potentials (RECPs) [13] to describe the core electrons
3.1. Synthesis and structural characterisation of [M3(CO)11(DPMO)]
(M ¼ Os, Ru; 1e4) and [Rh6(CO)15(DPMO)] (5e6)
We found that the reactions of transition metal carbonyl cluster
compounds [Os3(CO)12] and [Ru3(CO)12] in the presence of Me3NO
and the labile cluster [Rh6(CO)15(NCMe)] with a slight excess of the
DPMO, Ph2P(CH2)nP(O)Ph2 (n ¼ 2, POPE; n ¼ 3, POPP), result in the
formation of mono-substituted cluster complexes [Os3(CO)11(-
POPE)] (1), [Os3(CO)11(POPP)] (2), [Ru3(CO)11(POPE)] (3),
[Ru3(CO)11(POPP)] (4), [Rh6(CO)15(POPE)] (5), and [Rh6(CO)15(-
POPP)] (6) under mild conditions. Complexes 1e6 are moderately
air-stable and not destroyed on silica.
of Os, Ru, Rh and Ga atoms and split-valence (double-z) quality
basis sets to describe their valence electrons. For the heavier group
8 and 9 transition metals (Os, Ru, Rh), the LANL2DZ basis sets were
augmented by adding one set of f polarisation functions (orbital
exponents 0.886 for Os, 1.235 for Ru, and 1.350 for Rh) [14]. For Ga,
the LANL2DZ basis set was augmented by one set of d polarisation
functions (orbital exponent 0.16, as used by Timoshkin et al. in
[15]). For the non-metal atoms Cl, P, O, C, and H, all-electron split-
valence 6-311G(d,p) basis sets were employed [16]. The combina-
tion of all these basis sets is denoted as Basis Set System I (BS-I).
Energy decomposition analyses (EDA) [17] were performed using
the Amsterdam Density Functional (ADF) program developed by
Baerends and others [18e20]. The numerical integration was per-
formed using the procedure developed by te Velde et al. [19] The
molecular orbitals (MOs) were expanded in a large uncontracted set
of Slater-type orbitals (STOs): TZ2P (no Gaussian functions are
P2 O12
P1
TMC
n
involved) [20]. The basis set of triple-z quality was used for all non-
and metal atoms and augmented with two set of polarisation func-
tions on each atom (e.g. for non-metal atoms: 2p and 3d on H; 3d and
4f on C, O, P, and Cl). An auxiliary set of s, p, d, f and g STOs was used to
fit the molecular density and to represent the Coulomb and exchange
potentials accurately in each self-consistent field cycle. All energies
were calculated at the B3LYP level (20% Hartree-Fock exchange);
electron correlation was treated in the VoskoeWilkeNusair (VWN5)
parameterisation [21]. Scalar relativistic effects were accounted for
using the zeroth-order regular approximation (ZORA) [22].
In order to take into account the environment continuum
medium effects modeling the situation in solution, the B3LYP
functional was combined with the Polarisable Continuum Model
(PCM) in toluene (ε ¼ 2.3741) and chloroform (ε ¼ 4.7113). The gas-
phase geometries were thus re-optimised in corresponding solu-
tions using the Gaussian 09 program package. The radii and non-
electrostatic terms were taken from the SMD solvation model
developed by Truhlar and co-workers [23]. The optimised geome-
tries were verified through vibrational analysis to undertake their
characterisation as true minima (number of imaginary frequencies,
NImag ¼ 0), transition states (NImag ¼ 1) or higher order saddle
points (NImag ¼ 2, 3, etc.).
TMC = [Ru3(CO)11], [Os3(CO)11], [Rh6(CO)15]
The single crystals of 1 and 2 were isolated from corresponding
solvents/mixtures (see Experimental) at þ4 ꢂC. The solid-state
structures of the compounds were established by single-crystal
X-ray diffraction analyses. Compound 1 crystallises in the triclinic
space group P ꢁ1, whereas 2 crystallises in the monoclinic space
group P 21/c. Molecular structures of 1 and 2 are illustrated in Fig. 1;
crystallographic data are collected in Table 1; selected structural
parameters are given in Table 2.
The molecular structures of 1 and 2 are very similar and consist
of 11 terminal CO groups and a DPMO ligand coordinated to the
triangular Os3 skeleton in a terminal manner through the phos-
phorus atom. The OseOs bond lengths in 1 and 2 fall in the range
from 2.847(2) to 2.9255(2) Å and the Os(1)eP(1) bond lengths are
equal to 2.352(5) and 2.361(6) Å, respectively. As a result, the
observed values of the bond lengths are comparable to those in
other previously reported [Os3(CO)11(PR3)] clusters with terminal
Fig. 1. Molecular structures of complexes 1 (left) and 2 (right).

26
K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
Table 2
atom has a considerable low-field shift with respect to the phos-
Selected bond lengths [Å] for 1, 2, and 7.
phorus resonance in a free ligand. Such a behaviour is typical for
a phosphane coordinated in the ligand environment of Os3 [25,26],
Ru3 [24,26,30,31], and Rh6 clusters [29,32]. Secondly, the low-field
signal is assigned to the phosphorus atom P(2) of “dangling”
phosphane oxide [29,33]. The observed coupling constants are due
to interaction of the phosphorus atoms in the POPE and the POPP.
While the IR spectra of 1e4 in CH2Cl2 solutions show only the
peaks corresponding to the terminal CO ligands in the carbonyl
region, the IR spectra of 5 and 6 in CH2Cl2 display bands associated
with the stretching vibrations of both a terminal and m3-bridging CO
group in the same region (see Experimental and SI). Relative posi-
tions and intensities of the observed signals are in good agreement
with those obtained for the mono-substituted [Os3(CO)11(PR3)]
[25,26], [Ru3(CO)11(PR3)] [24,26,30], and [Rh6(CO)15(PR3)] clusters
[34]. As a result, the structures of compounds 3e4 can be described
as metal triangles surrounded by 11 terminal carbonyl groups and
terminal phosphane ligands, POPE or POPP, coordinated tothe metal
skeleton through the phosphorus atom in an equatorial position
likewise 1 and 2. Clusters 5e6 are Rh6 octahedrons with 11 terminal
CO and 4 face-bridging CO groups, and a terminal phosphane ligand.
1
2
7
Os(1)eOs(3)
Os(2)eOs(1)
Os(3)eOs(2)
Os(1)eP(1)
P(1)eC(12)
C(13)eC(12)
C(13)eP(2)
C(13)eC(38)
C(38)eP(2)
P(2)eO(12)
O(12)eGa(1)
C(1)eO(1)
2.8893(13)
2.9255(12)
2.8822(15)
2.352(5)
2.876(2)
2.847(2)
2.867(2)
2.361(6)
1.83(2)
2.8596(8)
3.0306(9)
2.8687(8)
2.344(3)
1.825(9)
1.510(13)
1.787(9)
1.853(17)
1.50(3)
1.815(15)
1.55(3)
1.53(4)
1.79(3)
1.48(2)
1.459(13)
1.515(6)
1.843(6)
1.150(13)
1.147(13)
1.129(13)
1.154(5)
1.12(2)
1.22(3)
1.23(3)
1.17(4)
1.19(4)
C(2)eO(2)
C(3)eO(3)
coordinated phosphanes [24e26]. The DPMO ligand in 1 and 2
occupies an equatorial position on the osmium triangle. The values
of its P]O bond lengths,1.459(13) in 1 and 1.48(2) Å in 2, are similar
to those found in free phosphane oxides [27,28]. In addition, 1 and 2
comprise coordination sites at the O(12) atom of the DPMO that are
accessible for further electrophilic attack of a Lewis acid.
The structures of compounds 1e6 in solution were characterised
by spectroscopic and spectrometric methods. The data obtained
were shown to be very similar for the pairs of complexes 1e2, 3e4,
and 5e6 due to minor differences in the ligand construction of the
DPMO. The FABþ mass spectra of 1e6 display the signals of corre-
sponding molecular ions. The observed isotopic distribution
pattern of each molecular ion is in excellent accordance with their
calculated one (see Supplementary Information; denoted as SI
below). The 31P NMR and IR spectroscopic data of 5 are identical to
the data published by Tunik et al. [29] for the rhodium cluster
complex [Rh6(CO)15(Ph2P(CH2)2P(O)Ph2)]. The 31P NMR spectrum
of each complex, 1e6, contains two signals of the equal intensity
(Table 3). Firstly, the high-field signal is assigned to the phosphorus
atom P(1) coordinated to the metal core. The chemical shift posi-
3.2. Synthesis and structural characterisation of
[M3(CO)11(DPMO)(GaCl3)] (M ¼ Os, Ru; 7e10) and
[Rh6(CO)15(DPMO)(GaCl3)] (11e12)
Transition metal cluster complexes 1e6 react with GaCl3 in
toluene solution to yield coordination-based molecular assemblies
7e12, respectively, in which a diphosphane monoxide linker
connects both the transition metal cluster core and the main group
metal centre. The reactions of 5 or 6 with GaCl3 occur at room
temperature without measurable cluster core decomposition,
whereas the reactions between 1e4 and GaCl3 need a lower
temperature to prevent the metal skeleton deconstruction.
Compounds 7, 8, 11, and 12 are moderately air-stable and they are
not destroyed on short silica column. Compounds 9 and 10 have
relatively short life time in solution as well as in the solid state.
1
tion of P(1) along with typical JRheP coupling constants obtained
for 5 and 6 confirms such an assignment. The signal of the P(1)
Table 3
31P NMR data of 1e12.
Compound
d
, ppm
nJ, Hz
R3P
R3P]O
POPE free
POPP free
ꢁ11.9
ꢁ18.3
R3PeM
ꢁ6.9
32.7
32.2
3JPeP ¼ 49
4JPeP ¼ 2
[Os3(CO)11(POPE)], 1
[Os3(CO)11(POPP)], 2
[Os3(CO)11(POPE)
(GaCl3)], 7
[Os3(CO)11(POPP)
(GaCl3)], 8
[Ru3(CO)11(POPE)], 3 30.2
[Ru3(CO)11(POPP)], 4 26.8
[Ru3(CO)11(POPE)
(GaCl3)], 9
30.6
31.8
52.6
3JPeP ¼ 48
4JPeP ¼ 2
3JPeP ¼ 44
ꢁ9.5
ꢁ12.0
ꢁ13.3
53.4
4JPeP ¼ 4
31.3
31.4
52.9
3JPeP ¼ 45
4JPeP ¼ 2
3JPeP ¼ 40
The single crystals of 7 were isolated from CDCl3 solution
at þ4 ꢂC and its solid-state structure was established by X-ray
diffraction analysis. Compound 7 crystallises in the monoclinic
space group P 21/n. The structural representation of 7 is shown in
Fig. 2; crystallographic data are collected in Table 1; and selected
structural parameters are given in Table 2.
The molecular structure of 7 consists of two main units
involving the complex structural fragment 1 and GaCl3. The latter is
coordinated to 1 via the oxygen atom O(12). In contrast to the
trigonal planar configuration of a non-coordinated GaCl3 molecule,
the gallium atom in the {OGaCl3} fragment of 7 displays a tetrahe-
dral coordination environment (Fig. 2). The OseOs bond lengths in
22.4
[Ru3(CO)11(POPP)
(GaCl3)], 10
20.4
53.5
4JPeP ¼ 4
PeRh
P]O
[Rh6(CO)15(POPE)], 5 21.2
[Rh6(CO)15(POPP)], 6 18.2
30.6
31.5
53.9
55.4
1JRheP ¼ 135,
2JRheP ¼ 4, 3JPeP ¼ 38
1JRheP ¼ 134,
2JRheP ¼ 3
3JPeP ¼ 38
e
[Rh6(CO)15(POPE)
(GaCl3)], 11
19.8
17.9
1JRheP ¼ 133,
2JRheP ¼ 4, 3JPeP ¼ 39
1JRheP ¼ 129,
2JRheP ¼ 3
3JPeP ¼ 39
[Rh6(CO)15(POPP)
(GaCl3)], 12
e

K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
27
Secondly, the high-field resonance is assigned to the phosphorus
atom P(1) coordinated to the metal core. Interestingly, the P(1)
resonance in 7e10 is up-shifted when compared to that in the 31P
NMR spectra of 1e4. This means that the electronic density on the
P(1) atom bonded to the Os3 or Ru3 metal cores increases when Ga is
coordinated to the opposite site (to the O(12) atom) of the DPMO
ligand. The IR spectra of 7e10 in CH2Cl2 solutions show only the
peaks corresponding to the terminal CO ligands in the carbonyl
region. Furthermore, their frequencies are shifted to high energy
field compared to those in 1e4 (see Experimental and SI). Overall,
the spectral behaviour of the studied molecular systems is complex,
but somewhat similar, albeit we observe some non-typical changes
in the IR spectra of 7e10 with respect to 1e4. Moreover, from
analysis of the electron density distribution for 1e10 it can be
concluded that only minor charge transfer effects operate when the
three units (carbonyl cluster, GaCl3, and spacer) assemble together
(see SI, Tables S1, S2).
In the case of cluster compounds 11 and 12, their 31P NMR and IR
spectroscopic data are very similar to those of 5 and 6 with the
exception of the observed low-field shift of the P(2) atom resonance.
In contrast to the complexes with a triangular core, the 31P NMR and
IR spectra of 11 and 12 demonstrate no high-field shifts for the P(1)
atom and the CO groups, respectively (see Table 3, Experimental and
SI). This may be indicative of the fact that the coordination of GaCl3
to the DPMO ligand of 5 and 6 activates no change in the electron
structure of the {Rh6(CO)15P} fragment. Furthermore, such
a behaviour might be related to the three-dimensional aromaticity
of the closed-face octahedral rhodium cluster system [35] that
stabilises the octahedral Rh6 architecture towards any external
electron influences.
Fig. 2. Molecular structure of 7.
7 fall in the range 2.8596(8)e3.0306(9) Å. The POPE ligand occupies
an equatorial position on the osmium triangle likewise 1. The
Os(1)eP(1) bond length is equal to 2.344(3) Å and it is thus slightly
shorter than that in 1. The P(2)eO(12) bond length in 7 is elongated
to 1.515(6) Å with respect to that in 1 and accordingly to the one in
a free phosphane oxide [28]. A somewhat analogous scenario is
observed for the mononuclear gallium complexes with the
terminal and chelate phosphane oxides [6,7].
The structures of 7e12 in solutions were characterised by spec-
troscopic and spectrometric methods. The data obtained were
shown to be very similar for the pairs of complexes 7e8, 9e10 and
11e12 like in the previous case (see Section 3.1). According to
spectroscopic data obtained for 7e12, the latter preserve their
overall structural composition as well as the structure of transition
metal carbonyl cluster skeleton after the electrophilic coordination
of GaCl3 to the spacer. The FABþ mass spectra of compounds 7e12
display the signals of their corresponding molecular ions. The
observed isotopic distribution pattern of each molecular ion is in
excellent accordance with their calculated one (see SI). The 31P NMR
spectrum of each complex, 7e12, contains two signals of the equal
intensity (Table 3). Firstly, the presence of the low-field resonance in
the 31P NMR spectrum is compatible with the structural pattern
mentioned above. The P(2) signal is substantially down-shifted
when compared to that in the 31P NMR spectra of 1e6, in accor-
dance with literature data [7]. This indicates a relatively high acidity
of the Ga coordination centre in 7e12 that elongates the P(2)eO(12)
bonds, as observed e.g. in the crystal structure of 7 (Table 2).
3.3. Quantum chemical calculations
The B3LYP optimised gas-phase structures of [M3(CO)11(PO-
PE)(GaCl3)] with M ¼ Os (7), Ru (9) and [Rh6(CO)15(POPE)(GaCl3)]
(11) complexes are represented in Fig. 3. As we can see, the
constitution of the equilibrium geometries 7comput and 9comput is
not influenced by the nature of the transition metal (M ¼ Os, Ru).
The values of their dihedral M(1)eP(1)eP(2)eGa angles are
around ꢁ69ꢂ; the MeM and M(1)eP(1) bond lengths change only
insignificantly, whereas the values of the P(2)eO and GaeO bonds
do not change at all. The experimental value of the dihedral Os(1)e
P(1)eP(2)eGa angle in 7 is equal to ꢁ48.9ꢂ. This shows that the
structure of complex 7 is somewhat influenced by crystal packing
effects; the solid-state structure thus becomes more reduced in its
volume. The constitution of 11comput, in its turn, differs from the
previous ones (Fig. 3). The dihedral Rh(1)eP(1)eP(2)eGa angle is
Fig. 3. The equilibrium gas-phase structures 7comput (left), 9comput (centre), and 11comput (right) and their structural parameters.

28
K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
“relaxed” gas-phase geometry of the latter in a toluene and CHCl3
solvent shell. The results obtained for the equilibrium structure
comput indicate that: (i) the dihedral Os(1)eP(1)eP(2)eGa angle is
7
slightly reduced towards lower value of ca. ꢁ62ꢂ in both toluene
and CHCl3; (ii) the GaeO bond lengths moderately shorten with an
increase in the polarity of the solvent (dGaeO ¼ 1.875 Å and 1.858 Å
in toluene and CHCl3, respectively); (iii) in contrast, the Os(1)eP(1)
and P(2)eO bond lengths elongate monotonically (dOs(1)e
¼ 2.428 Å, dP(2)eO ¼ 1.546 Å in toluene; dOs(1)eP(1) ¼ 2.430 Å,
P(1)
dP(2)eO ¼ 1.551 Å in CHCl3); (iv) the HOMOeLUMO gap of 7comput
in both solutions does not increase. In addition, the equilibrium
structure 7comput is energetically more favourable by 2.5 kcal molꢁ1
(incl. zero-point energy, ZPE, correction) in CHCl3 than in toluene.
Elimination of GaCl3 from 7 leads to avery interesting situation in
complex 1. According to our DFTcalculations, the latter exhibits two
equilibrium isostructures, 1Acomput and 1Bcomput, which are the
rotamers related by rotation about the P(1)eCeCeP(2) linkage
(Fig. 4). The energy difference between these rotameric structures in
the gas phase is only ꢁ1.2 kcal molꢁ1 (incl. ZPE correction). The more
stable 1Bcomput structure matches the experimental one (1; Fig. 1).
The situation becomes more complex by coordination of Ga to the
oxygen atom of the diphosphane monoxide ligand (POPE) of 1. As
observed by X-ray crystallography, complex 7 in the solid-state
Fig. 4. The B3LYP optimised gas-phase structures of rotamers 1Acomput (left) and
1Bcomput (right).
ca. 171ꢂ and the Rh(1)eP(1), P(2)eO, and GaeO bond lengths
slightly increase compared to those in 7comput and 9comput. As
a result, the metalemetal bond distances in these three studied
assemblies moderately elongate when going down the heavier
group 8 transition metals (from Ru to Os) and shorten when going
left to right across the period 5 transition metals (from Ru to Rh).
In order to examine the influence of homogeneous solvent
medium on the structure and properties of 7, we re-optimised the
(unfd)
Fig. 5. The B3LYP optimised structures of rotamers 7comput (left) and 7
(right). 7comput corresponds to the experimental structure of 7 observed in the solid state, whereas
comput
(unfd)
7
is the more stable structure in the gas phase.
comput
Fig. 6. The gas-phase interactions between the units constitutive of coordination-based molecular assembly 7comput studied by means of a quantitative energy decomposition
analysis (EDA). Top: interaction of [Os3(CO)11] with (POPE)GaCl3. Bottom: interaction of [Os3(CO)11(POPE)] (1Bcomput) with GaCl3.

K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
29
Table 4
Energy decomposition analysis (in kcal molꢁ1) of the interactions between the units
constitutive of the equilibrium structure 7comput
albeit the orbital interaction terms,
cantly contribute to the attractive interactions between the building
units of 7comput. Even though strong Pauli repulsion, EPauli, liable for
the destabilising interactions is observed, the strongly attractive or
stabilising electrostatic interactions outweigh quantum mechanical
D
Eoi (approx. 40%), also signifi-
.
D
EDAa
[Os3(CO)11(POPE)(GaCl3)], 7comput
[Os3(CO)11] þ (POPE)GaCl3
[Os3(CO)11(POPE)] þ GaCl3
b
ones, i.e.
between the considered fragments (Table 4).
The preparation energy, Eprep, which is the energy difference
DEoi
þ
DEPauli, [36]andaremainlyresponsibleforthebinding
D
D
D
D
D
Eint
ꢁ42.9
ꢁ41.4
EPauli
Velstat
Eoi
164.7
101.1
ꢁ132.6 (63.9%)
ꢁ75.0 (36.1%)
5.1
ꢁ86.5 (60.7%)
ꢁ56.0 (39.3%)
16.5
D
between the equilibrium structures of the fragments illustrated in
Fig. 6 and the energies of those in the geometries that theyacquire in
the equilibrium structure 7comput, is only negligible for the interac-
tion between [Os3(CO)11] and (POPE)GaCl3. This contrasts with
Eprep
c
De
37.8
24.9
a
At ZORA-B3LYP/TZ2P.
b
c
DEint
¼
D
Velstat
þ
DEPauli
þ
DEoi.
Eprep.
D
Eprep of 7comput obtained from the interaction of [Os3(CO)11(POPE)]
(1Bcomput) with GaCl3 (Fig. 6). Interestingly, the major energy
contribution to this Eprep term comes from the GaCl3 moiety which
DE (¼ ꢁDe) ¼
DEint
þ
D
D
favours more compact (or “folded”) molecular structure (corre-
sponds to 7comput) in its volume (see Figs. 2 and 5). In their turn, the
results obtained from the structural optimisations of 7 in the gas
phase and in solution reveal that the “unfolded” structural shape of
changes its trigonal planar geometry to a distorted tetrahedral one
by coordination to 1Bcomput. The values of the bond dissociation
energies (BDEs), De, calculated from the two models for 7comput
reveal that the studied interactions are relatively weak and can be
easily broken (Fig. 6, Table 4). Overall, the Os(1)eP(1) bond formed
bythe interaction of [Os3(CO)11] and (POPE)GaCl3 ismorestable than
the GaeO bond originated from the interaction between 1Bcomput
and GaCl3. It is also noteworthy that the fairly low stability of
complexes 7, 9, and 11 observed from their solid-state behaviour
might be the result of the relatively low HOMOeLUMO gaps [37]
found for 7comput (0.94 eV), 9comput (0.92 eV), and 11comput
this complex (referred to as 7(unfd)
comput) is energetically more stable by
3.3 kcal molꢁ1 in the gas phase, and by 1.1 kcal molꢁ1 in toluene and
0.2 kcal molꢁ1 in CHCl3 than the “folded” one of 7comput according to
the relative energies (incl. ZPE correction) calculated at their equi-
librium structures (Fig. 5). The observation of the two rotameric
structures, 7comput and7(unfd)
comput, isrelated tothat fact that thepotential
energy surface of the studied OseGa bridged complex is fairly flat.
The dissimilarities observed between the gas and solution
phases clearly demonstrate the importance of the continuum
medium effects not only on the geometric shape of the
coordination-based molecular assembly 7 but also on its energetic
features. Thus, the phase differences are expected to have an effect
on 7 of which constitution may, furthermore, be influenced by the
crystallisation conditions (solvent, temperature, etc.). For example,
a more polar solvent (e.g. CDCl3) should facilitate the rotation about
the P(1)eCeCeP(2) linkage due to the possible weakening of the
interconstitutive Os(1)eP(1) and P(2)eO bonds. In addition, 7comput
(0.91 eV) as well as of the low BDEs as shown in the case of 7comput
.
4. Conclusions
We showed that reactions of the triangular clusters [M3(CO)12
]
(M ¼ Ru, Os), and theoctahedralcluster [Rh6(CO)15(NCMe)]withnon-
symmetrical bifunctional diphosphane monoxides (DPMOs) led to
the formation of new mono-substituted carbonyl cluster complexes
[M3(CO)11(DPMO)] (M
¼
Ru, Os; 1e4) and [Rh6(CO)15
(DPMO)] (5, 6), respectively. We demonstrated that phosphane
coordination to the metal cluster (1e6) can be followed by func-
tionalisation of the pendant phosphane-oxide moiety with GaCl3 to
fabricate novel heterometallic coordination-based molecular
assemblies [M3(CO)11(DPMO)(GaCl3)] (7e10) and [Rh6(CO)15(DP-
MO)(GaCl3)] (11e12) (Fig. 7). The crystalstructures of compounds 1, 2,
and 7 were determined by single-crystal X-ray diffraction. As a result,
we were able to synthesise and structurally characterise the first
organometallic osmiumegallium mixed complex, 7. On the basis of
experimental data and quantum chemical calculations, we estab-
lished that (i) the condensed media (crystal, solution) have an effect
on the structure of 7, (ii) the latter is influenced by the type of solvent
(a more polar solvent leads to almost isoenergetic rotameric struc-
tures), and (iii) the nature of the interconstitutive metaleligand
should obviously be better stabilised by non-specific intermolec-
(unfd)
ular interactions in the crystal structure than 7
.
comput
In order to gain further insight into the nature of the intercon-
stitutive metaleligand interactions in 7, energy decomposition
analyses (EDA) of the equilibrium gas-phase structure 7comput were
performed for two models constructed from different fragments: (i)
[Os3(CO)11] and (POPE)GaCl3, and (ii) [Os3(CO)11(POPE)] (1Bcomput
)
and GaCl3 (Fig. 6, Table 4). The EDA shows that the interaction ener-
gies, DEint, of [Os3(CO)11] with (POPE)GaCl3 and of1Bcomput with GaCl3
areverysmall(ca. ꢁ40kcalmolꢁ1).Thisisindicativeofarelativelylow
strength of binding between the units. Furthermore, these intercon-
stitutive interactions are predominantly electrostatic in nature
(DVelstat is approx. 60% of all bonding interactions, i.e.
DVelstat
þ
DEoi),
Fig. 7. Two-step synthesis of heterometallic coordination-based molecular assemblies 7e12.

30
K.Yu. Monakhov et al. / Journal of Organometallic Chemistry 714 (2012) 22e31
N. Rega, N.J. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo,
J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi,
C. Pomelli, J.W. Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski,
G.A. Voth, P. Salvador, J.J. Dannenberg, S. Dapprich, A.D. Daniels, O. Farkas,
J.B. Foresman, J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian 09, Revision B.01,
Gaussian, Inc., Wallingford CT, 2010.
interactions in 7 is predominantly electrostatic. From the experi-
mental and computational analyses of complexes 1e12, it can be
concluded that their molecular structures are evidently maintained
not only in the solid state and the gas phase but also in solution.
Although, the three units (i) carbonyl cluster, (ii) GaCl3, and (iii) spacer
assemble together without modifying their individual properties
(thatisbeingsupportedbyinspectionofanalyticalandcomputational
protocols), the authors are very encouraged to see a detailed theo-
retical analysis of the other linked molecular systems in which
metallic elements of different nature and properties willbe combined
in order to seek out the very promising intramolecular electron
transport effects. Our work opens a prospect for further compre-
hensive investigations of the types of assemblies herein presented.
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