Journal of Inorganic and General Chemistry
SHORT COMMUNICATION
Zeitschrift für anorganische und allgemeine Chemie
nances: δ = 209.2 (s, broad; assigned to the carbonyl ligands using the caption in Figure 1. Furthermore, the corresponding
in proximity to the P atoms), and four signal groups at 139.1, parameters agree very well with the observed ones for diruth-
131.1, 130.4, and 128.8 which were assigned to carbon C enium complexes bridged by dppa.[9,10] The ability to form
atoms of the aromatic rings on phosphorus. The infrared spec- intermolecular hydrogen-bridge bondings of the NH group of
trum of our compound 1 (ATR, solid) showed a comparable dppa was already found in the compound [Ru2(CO)4(μ-dppa)
pattern as observed for [Ru3(CO)10(μ-dppm)][4] indicating the (μ-H)(μ-NO)(μ-PBut2)]BF4 where the tetrafluoridoborate as
presence of only terminal carbonyl ligands.
the counterion functioned as the hydrogen-bridge bonding ac-
Red-orange crystals of 1 suitable for X-ray diffraction were ceptor part.[10] The same behavior was observed in crystals of
obtained by the slow diffusion method from dichloromethane/ 1·C4H8O2 where the NH group of dppa formed a strong
dioxane at room temperature overnight. Thus 1 crystallized as hydrogen bond towards a co-crystallized dioxane molecule re-
¯
dioxane solvate in the triclinic space group P1 with two mol- sulting from the crystal growing process. During the slightly
ecules in the unit cell. A view of the molecular structure of 1 bent (162.00°) intermolecular hydrogen bridge N1–H1···O11
in the crystal is depicted in Figure 1, selected bond lengths and the following distances were found: 0.8800, 2.0800, and
angles are given in the caption.
2.925(2) Å. The fortunate circumstance of the dioxane solvate
formation in crystals of 1 allowed us to obtain a better wR2
value during the structure refinement as reported for the same
compound in an earlier report.[7]
Conclusions
The herein reported investigations describes the convenient
high-yield synthesis of the trimetal cluster [Ru3(CO)10(μ-dppa)]
(1) obtained by the sodium benzophenone ketyl-induced substi-
tution of two carbonyl ligands in [Ru3(CO)12] towards the
small bite-angle PNP ligand bis(diphenylphosphanyl)amine
(dppa). A crystal structure determination of 1 on its dioxane
solvate was carried out, whereas crystals of the compound ex-
hibited a strong hydrogen-bridge bonding between the NH
function of the dppa ligand as the hydrogen-bridge bonding
donor and one oxygen atom of the dioxane molecule as the
hydrogen-bridge bonding acceptor in the solid. Thus a new
crystal and molecular structure of the title compound was
found, and the fortunate circumstance of the dioxane solvate
formation in the crystal allowed us to reach a more better wR2
value during the structure refinement as reported for the chlo-
Figure 1. ORTEP plot of the molecular structure of 1 in the crystal
(Ellipsoids are drawn with 50% probability level). Selected bond
lengths (Å) and angles (°): Ru1–Ru2, 2.8390(4); Ru1–Ru3, 2.8710(4);
Ru2–Ru3, 2.8271(4); Ru3–P1, 2.3188(6); Ru2–P2, 2.3027(6); P1–N1,
1.6920(18); P2–N1, 1.6922(18); N1–H1, 0.8800. Ru2–Ru1–Ru3, roform solvate of [Ru3(CO)10(μ-dppa)] in the earlier report.[7]
59.35(1); Ru1–Ru3–Ru2, 59.76(1); Ru1–Ru3–P1, 146.34(2); Ru2–
Ru3–P1, 87.88(2); Ru3–Ru2–P2, 92.70(2); P1–N1–P2, 123.27(11);
Ru3–P1–N1, 111.96(7); Ru2–P2–N1, 112.21(6); P2–N1–H1, 118.00.
N1–H1···O11: 2.925(2); 162.00°.
Experimental Section
General: All preparative work was carried out under a dry nitrogen
atmosphere using standard Schlenk techniques. Chemicals were pur-
chased from Sigma/Aldrich and used as received. IR spectra were re-
corded from solids with a JASCO FT/IR-4600 spectrometer equipped
Molecules of 1 exhibit a triangular metal core with three
ruthenium-ruthenium bonds whose lengths are comparable to
similarly constituted clusters such as [Ru3(CO)10(μ-dppm)].
with an ATR unit. NMR spectra were recorded using a Jeol Eclipse
The literature known parameters are: Ru1–Ru2, 2.834(1),
400 instrument operating at 400 MHz (1H), 100 MHz (13C), and at
Ru1–Ru3, 2.841(1), and Ru2–Ru3, 2.860(1) Å.[8] In
162 MHz (31P). Chemical shifts are given in ppm relative to TMS (1H,
[Ru3(CO)10(μ-dppm)] as well as in 1 the edge bridged by the
bidentate phosphane ligand was found as slightly shorter than
the other two. The same observation was made for the origi-
nally reported structure of [Ru3(CO)10(μ-dppa)] for which the
corresponding bond lengths were found: Ru1–Ru1a,
2.8287(11) (bridged by dppa), Ru1a–Ru2, 2.8545(10), and
Ru1–Ru2, 2.8546(10) Å.[7]
In general, the molecules of both crystal modifications exhi-
bit very similar geometric and bonding parameters. Thus for
[Ru3(CO)10(μ-dppa)][7] the following data were reported: P1–
N1, 1.688(4) and Ru1–P1, 2.307(2) Å, as well as P1–N1–P1a,
13C) and 85% H3PO4 (31P). Elemental analyses were performed by
the Microanalytical Laboratory of the Department of Chemistry, LMU
Munich, using a Heraeus Elementar Vario EL instrument.
Synthesis of 1: [Ru3(CO)12] (320 mg, 0.5 mmol) and dppa (193 mg,
0.5 mmol) were placed in a Schlenk tube and 30 mL of deoxygenated
THF were added. The mixture was stirred and warmed to about 50 °C
to dissolve the metal carbonyl. At this point some drops of a sodium
benzophenone ketyl solution were added, while a strong carbon mon-
oxide evolution was registered and the solution rapidly darkened to
orange-brown. After stirring for 30 min at room temperature the re-
sulting dark red-brown solution was reduced to about 1 mL in vacuo.
127.1(5)°. For 1·C4H8O2 these parameters can be compared by Addition of 20 mL of methanol afforded orange-red crystals, which
Z. Anorg. Allg. Chem. 2020, 1787–1789
© 2020 The Authors. Zeitschrift für anorganische und allgemeine Chemie
published by Wiley-VCH GmbH
B?ttcher, Hans-Christian
