Synthesis and crystal structure of three carborane complexes, [M{7,8-(OPPh2)2-7,8-C2B9H 10}2] (M = Cu, Zn) and [Ni(thf){7,8-(OPPh 2)2-7,8-C2B9H10} 2]·thf

Article abstract of DOI:10.1002/ejic.200600679

Three new carborane complexes containing the bis(phosphoryl)-nido-carborane ligand, [Cu{7,8-(OPPh₂)₂-7,8-C₂B ₉H₁₀}₂] (1), [Zn{7,8-(OPPh₂) ₂-7,8-C₂B₉H₁₀}₂] (2), and [Ni(thf){7,8-(OPPh₂)₂-7,8-C₂B ₉H₁₀}₂]·thf (3), were synthesized by the reactions of 1,2-(PPh₂)₂-1,2-C₂B ₁₀H₁₀ with CuCl₂·2H₂O, ZnCl₂, and NiCl₂·6H₂O, respectively, in ethanol in air. Two other compounds, 1-(OPPh₂)-2-(PPh ₂)-1,2-C₂B₁₀H₁₀ (4) and H[7,8-(OPPh₂)₂-7,8-C₂B₉H ₁₀]·0.25C₂H₅OH (5), were also obtained through the oxidation of the closo ligand in air. All new compounds were characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR spectroscopy, and single-crystal X-ray diffraction. In complexes 1 and 2, the metal atoms are coordinated to the four oxygen atoms of the two bidentate bis(phosphoryl) ligands [7,8-(OPPh₂)₂-7,8-C ₂B₉H₁₀]^- and adopt a square-planar geometry. For complex 3, the molecular structure reveals that the geometry at the nickel atom is square-pyramidal, with four oxygen atoms from the four OPPh₂ groups and one additional one from a thf molecule. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Full text of DOI:10.1002/ejic.200600679

FULL PAPER
DOI: 10.1002/ejic.200600679
Synthesis and Crystal Structure of Three Carborane Complexes, [M{7,8-
(OPPh2)2-7,8-C2B9H10}2] (M = Cu, Zn) and [Ni(thf){7,8-(OPPh2)2-7,8-
C2B9H10}2]·thf, and Two Carborane Compounds, 1-(OPPh2)-2-(PPh2)-1,2-
C2B10H10 and H[7,8-(OPPh2)2-7,8-C2B9H10]·0.25C2H5OH
Jianmin Dou,*[a] Daopeng Zhang,[a] Dacheng Li,[a] and Daqi Wang[a]
Keywords: Cu complexes / Zn complexes / Ni complexes / Carborane complexes / Oxidation / Degradation
Three new carborane complexes containing the bis(phosphor-
yl)-nido-carborane ligand, [Cu{7,8-(OPPh2)2-7,8-C2B9H10}2]
(1), [Zn{7,8-(OPPh2)2-7,8-C2B9H10}2] (2), and [Ni(thf){7,8-
(OPPh2)2-7,8-C2B9H10}2]·thf (3), were synthesized by the re-
actions of 1,2-(PPh2)2-1,2-C2B10H10 with CuCl2·2H2O, ZnCl2,
and NiCl2·6H2O, respectively, in ethanol in air. Two other
compounds, 1-(OPPh2)-2-(PPh2)-1,2-C2B10H10 (4) and H[7,8-
(OPPh2)2-7,8-C2B9H10]·0.25C2H5OH (5), were also obtained
through the oxidation of the closo ligand in air. All new com-
pounds were characterized by elemental analysis, FT-IR, 1H
and 13C NMR spectroscopy, and single-crystal X-ray diffrac-
tion. In complexes 1 and 2, the metal atoms are coordinated
to the four oxygen atoms of the two bidentate bis(phosphoryl)
–
ligands [7,8-(OPPh2)2-7,8-C2B9H10
]
and adopt a square-
planar geometry. For complex 3, the molecular structure re-
veals that the geometry at the nickel atom is square-pyrami-
dal, with four oxygen atoms from the four OPPh2 groups and
one additional one from a thf molecule.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
gated the effect of different reaction conditions on the prod-
ucts. When the reaction of 1,2-(PPh2)2-1,2-C2B10H10 with
NiCl2·6H2O was carried out in air, a new complex contain-
ing one bis(phosphanyl)-nido-carborane ligand and one un-
symmetrical semi-oxidized (phosphoryl)(phosphanyl) li-
gand with the formula [Ni{7-(OPPh2)-8-(PPh2)-7,8-
C2B9H10}{7,8-(PPh2)2-7,8-C2B9H10}] were obtained.[38]
This result indicates that the environment has an obvious
influence on the reaction. To continue with the reactions of
the bis(phosphanyl)-closo-carborane ligand with different
metal ions without the protection of inert gases, we investi-
gated three reactions of the bis(phosphanyl)-closo-carbor-
ane ligand with CuCl2·2H2O, ZnCl2, and NiCl2·6H2O in air
and obtained three new carborane complexes containing
the nido-[7,8-(OPPh2)2-7,8-C2B9H10]– anion, [Cu{7,8-
Introduction
The synthesis and properties of dicarba-closo-dodecabo-
rane, 1,2-C2B10H12, and the -nido-species, [7,8-C2B9H12]–,
were first reported in the early 1960s.[1–4] Since then, both
closo- and nido-carboranes have proven to be excellent
bulky and stable building blocks that allow for the synthesis
of a wide range of carborane derivatives and have shown a
lot of potential in various applications, including medicinal
chemistry, especially Boron Neutron Capture Therapy
(BNCT) of tumors, solvent extraction, materials science, ca-
talysis, host–guest chemistry, and coordination chemis-
try,[5–18] which made carborane chemistry all along an inter-
esting growth area.
In recent years, the 1,2-bis(phosphanyl) derivative of o-
carborane, 1,2-(PPh2)2-1,2-C2B10H10, and its partially de-
graded anion, nido-[7,8-(PPh2)2-7,8-C2B9H10]–, have at-
tracted much attention because of the coordinating capa-
bilities of the two phosphorus atoms. Up to now, complexes
containing the 1,2-(PPh2)2-1,2-C2B10H10 and nido-[7,8-
(PPh2)2-7,8-C2B9H10]– ligands and CuI,[19] RuII,[20]
AgI,[21,22] AuI,[23–29] PdII,[30–33] and Rh[34] have been re-
ported and characterized by single-crystal X-ray diffraction.
We are also interested in these kinds of complexes and have
reported on the synthesis and crystal structures of CuI,[35]
AuI,[36] NiII, PdII, and PtII complexes,[37] and we investi-
(OPPh2)2-7,8-C2B9H10}2]
(1),
[Zn{7,8-(OPPh2)2-7,8-
C2B9H10}2] (2), and [Ni(thf){7,8-(OPPh2)2-7,8-C2B9H10}2]·
thf (3). To the best of our knowledge, there has been no
report on the metal ion complex of the bis(phosphoryl)car-
borane ligand [7,8-(OPPh2)2-7,8-C2B9H10]–, which has been
reported by Teixidor’s group.[39] In addition, the oxidation
and degradation process of the free bis(phosphanyl)-closo-
carborane ligand, 1,2-(PPh2)2-1,2-C2B10H10, in air was
studied for the first time.
Results and Discussion
Synthesis and Spectral Characterization
In our recent work[38] we found that, with or without the
protection of N2, results of the reactions of the bis(phos-
[a] Department of Chemistry, Liaocheng University,
Liaocheng 252059, P. R. China
E-mail: jmdou@lcu.edu.cn
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53

J. M. Dou, D. P. Zhang, D. C. Li, D. Q. Wang
FULL PAPER
Scheme 1. The rational reaction process for the preparation of the complexes 1 to 3 [M = Cu(1), Zn(2), Ni(3)].
phanyl)-closo-carborane ligand 1,2-(PPh2)2-1,2-C2B10H10 carborane skeleton degraded. The proposed mechanism for
with some NiII compounds were very different, indicating the partial degradation of the semi-oxidized (phospho-
that the reaction environment could play an important role ryl)(phosphanyl)-closo-carborane ligand, which is similar to
during the reaction process. By stirring the mixture of the degradation of 1-SR-2-PPh2-1,2-C2B10H10,[40] is shown
NiCl2·6H2O and the closo ligand for 6 h in ethanol at room in Scheme 2.
temperature, we obtained the complex [Ni{7-(OPPh2)-8-
(PPh2)-7,8-C2B9H10}{7,8-(PPh2)2-7,8-C2B9H10}]. However,
when the stirring time was increased to 12 h in air, both P
atoms of the initial bis(phosphanyl)-closo-carborane ligand
were oxidized, and a new complex containing the bis(phos-
phoryl)-nido-carborane ligand [7,8-(OPPh2)2-7,8-C2B9H10]–
was obtained. This result showed that both of the P atoms
could be oxidized, but the oxidation of the two P atoms did
not take place at the same time. Subsequently, the reactions
between CuCl2·2H2O, ZnCl2, and the bis(phosphanyl)-
Scheme 2. Proposed mechanism for the partial degradation of com-
pound 4.
closo-carborane ligand in a molar ratio of 1:1 in ethanol
The Ccage–P=O group pulls electron density off the cage,
were carried out. After the stirring process was continued and its electron-withdrawing capacity favors the removal of
for 6 h in air at room temperature, two complexes with the the B(3) atom (the boron atom adjacent to the carbon
formula [Cu{7,8-(OPPh2)2-7,8-C2B9H10}2] and [Zn{7,8- atom), especially under the attack of the nucleophilic sol-
(OPPh2)2-7,8-C2B9H10}2] were obtained. As indicated by vent. According to these results, we think that compound 4
their similar crystal data, listed in Table 2, these two com- is an intermediate formed during the oxidation and degra-
plexes are isostructural. The difference in the reaction times dation process of the closo ligand. This process may be ac-
of the above three reactions implied that the metal atom complished in three steps which occur in the following or-
itself could also affect the reaction process. The rational der: (1) the oxidation of one phosphorus atom, (2) the de-
reaction process for the preparation of these three com- gradation of the closo-carborane skeleton, and (3) the oxi-
plexes is shown in Scheme 1.
dation of another phosphorus atom.
With an aim to find out whether the phosphorus atom
All the three carborane complexes and two bis(phospho-
of the closo ligand could be oxidized and the carborane ryl)carborane compounds were characterized by FT-IR, 1H
skeleton could be converted from closo to nido by oxygen and 13C NMR spectroscopy. The IR spectra of compounds
without the presence of the metal ion, we studied another 1–5 are very similar to each other and exhibit absorptions
experiment. The free closo ligand 1,2-(PPh2)2-1,2-C2B10H10 characteristic of terminal B–H vibrations at 2510–
was suspended in ethanol, and the mixture was stirred for 2550 cm–1, which fall in the normal range of B–H vibration
8 h, while air was continually and slowly bubbled into the from 2450 to 2625 cm–1.[41] The absorption at about
reaction mixture. Contrary to our expectation, a compound 3100 cm–1 may be attributed to the νC–H stretching vi-
containing the closo-carborane skeleton, but not the nido bration of the benzene rings. Several peaks are found be-
form, with the formula 1-(OPPh2)-2-(PPh2)-1,2-C2B10H10 tween 1689 and 1400 cm–1, which may be assigned to the
(4), was obtained, in which also only one phosphorus atom νC=C stretching vibration. The peak at ca. 1400 cm–1 is the
was oxidized. A marked difference from the complex [Ni{7- in-plane deformation mode of the benzene ring, and the
(OPPh2)-8-(PPh2)-7,8-C2B9H10}{7,8-(PPh2)2-7,8-C2B9H10}] peak at ca. 1100 cm–1 is the absorption of νC(aryl)–P, which
was that the closo-carborane skeleton in this compound was is a little shifted, in keeping with phosphorus coordination
maintained. Following the procedure for the synthesis of to the carborane moiety. The strong absorption at about
compound 4, the mixture was stirred for 18 h, and a com- 1250–1260 cm–1 in all the compounds may be attributed to
pound with the formula H[7,8-(OPPh2)2-7,8-C2B9H10]· the P=O bond. The absorption at 700–750 cm–1 shows the
1
0.25C2H5OH (5) was obtained. This compound is very existence of the deformation cage. The H NMR spectra
similar to another neutral compound H[7,8-(OPPh2)2-7,8- (400.15 MHz) of these carborane compounds display a
C2B9H10], which has been obtained with very high yield common resonance pattern at about 7.1–7.6 ppm, which
(94–97%) by oxidation of 1,2-(PPh2)2-1,2-C2B10H10 with can be attributed to the aryl-H of the PPh2 groups. The
H2O2 in thf at 0 °C.[39] The aim of oxidizing another phos- resonance at ca. –2.2 ppm is the bridging H atom of B–
phorus atom of the semi-oxidized (phosphoryl)(phos- H–B in the three complexes.[19] In the 13C NMR spectra
phanyl)-closo-carborane ligand was fulfilled, but the closo- (100.63 MHz), the resonance at about 132–139 ppm can be
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Synthesis and Crystal Structure of Five Carborane Compounds
FULL PAPER
assigned to the benzene-ring C atoms, and that at ca. δ = 77 tively, which are slightly shorter than the mean value 1.87 Å
can be attributed to the carbon atom of carborane cage.[42] in [NH4][7,8-(PPh2)2-7,8-C2B9H10],[43] indicating that in
these nido species the oxidation of the P atom has an influ-
ence on the P–Ccage bond length. This conclusion could
also be proved by the corresponding bond lengths in
X-ray Crystallographic Study
[Ni{7-(OPPh2)-8-(PPh2)-7,8-C2B9H10}{7,8-(PPh2)2-7,8-
C2B9H10}][38] [P–C(7): 1.769(7), P–C(8): 1.867(7) Å]. The
C(7)–C(8) bond lengths, ranging from 1.593(7) to
1.606(8) Å in 1–3 are in good agreement with the corre-
sponding distance 1.61(2) Å in [NH4][7,8-(PPh2)2-7,8-
C2B9H10],[43] but obviously shorter than 1.697(4) Å in the
closo ligand 1,2-(PPh2)2-1,2-C2B10H10.[44] The angles P(1)–
C(7)–C(8) and P(2)–C(8)–C(7) in complexes 1–3 [120.4(3)–
The molecular structures of the new compounds 1–5 are
shown in Figure 1, Figure 2, Figure 3, Figure 4, and Fig-
ure 5 respectively, and the selected bond lengths and angles
of the three carborane complexes are listed in Table 1. A
common feature of the complexes 1–3 is that they all con-
tain the same bis(phosphoryl)-nido-carborane ligand [7,8-
(OPPh2)2-7,8-C2B9H10]–. The average P–Ccage distances in
the three metal complexes are 1.804, 1.809, 1.816 Å, respec-
Figure 3. The crystal structure of complex 3. The H atoms were
omitted for clarity.
Figure 1. The crystal structure of complex 1. The H atoms were
omitted for clarity.
Figure 2. The crystal structure of complex 2. The H atoms were
omitted for clarity.
Figure 4. The crystal structure of compound 4. The H atoms were
omitted for clarity.
Eur. J. Inorg. Chem. 2007, 53–59
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55

J. M. Dou, D. P. Zhang, D. C. Li, D. Q. Wang
FULL PAPER
Figure 5. The crystal structure of compound 5. The H atoms were omitted for clarity.
Table 1. Selected bond lengths [Å] and angles [°] for complexes 1, 2, and 3.[a]
1
2
3
Cu(1)–O(1)
Cu(1)–O(2)
P(1)–O(1)
P(2)–O(2)
P(1)–C(7)
P(2)–C(8)
C(7)–C(8)
C(7)–B(11)
1.913(4)
1.900(4)
1.525(4)
1.505(4)
1.804(6)
1.814(7)
1.606(8)
1.663(9)
1.652(10)
1.759(9)
1.742(2)
90.03(19)
180.0(1)
143.0(3)
136.9(3)
112.8(3)
115.7(3)
122.8(4)
122.4(4)
Zn(1)–O(1)
Zn(1)–O(2)
P(1)–O(1)
P(2)–O(2)
P(1)–C(7)
P(2)–C(8)
C(7)–C(8)
C(7)–B(11)
1.904(4)
1.931(3)
1.495(4)
1.506(4)
1.822(5)
1.810(6)
1.594(7)
1.654(8)
1.634(8)
1.720(8)
1.740(8)
90.63(16)
180.0(1)
137.1(2)
141.6(2)
115.6(2)
113.5(2)
122.3(4)
122.8(4)
Ni(1)–O(1)
Ni(1)–O(2)
P(1)–O(1)
P(2)–O(2)
P(1)–C(7)
P(2)–C(8)
C(7)–C(8)
C(7)–B(11)
2.011(4)
1.987(4)
1.501(4)
1.493(4)
1.801(6)
1.813(5)
1.608(8)
1.646(9)
1.631(9)
1.753(9)
1.738(8)
86.28(16)
170.68(15)
141.1(2)
161.6(2)
117.1(2)
113.3(2)
120.4(4)
124.6(4)
C(8)–B(9)
C(7)–B(2)
C(8)–B(3)
C(8)–B(9)
C(7)–B(2)
C(8)–B(3)
C(8)–B(9)
C(7)–B(2)
C(8)–B(3)
O(1)–Cu(1)–O(2)
O(1)–Cu(1)–O(1)#1
P(1)–O(1)–Cu(1)
P(2)–O(2)–Cu(1)
O(1)–P(1)–C(7)
O(2)–P(2)–C(8)
C(7)–C(8)–P(2)
C(8)–C(7)–P(1)
O(1)–Zn(1)–O(2)
O(1)–Zn(1)–O(1)#1
P(1)–O(1)–Zn(1)
P(2)–O(2)–Zn(1)
O(1)–P(1)–C(7)
O(2)–P(2)–C(8)
C(7)–C(8)–P(2)
C(8)–C(7)–P(1)
O(1)–Ni(1)–O(2)
O(1)–Ni(1)–O(4)
P(1)–O(1)–Ni(1)
P(2)–O(2)–Ni(1)
O(1)–P(1)–C(7)
O(2)–P(2)–C(8)
C(7)–C(8)–P(2)
C(8)–C(7)–P(1)
[a] Symmetry transformations used to generate equivalent atoms: complex 1: –x+1, –y+1, –z; complex 2: –x+1, –y+1, –z+2.
124.6(3)°] are slightly larger than the corresponding angles phoryl)carborane moieties are located at two opposite sides
[113.4(9) and 116.5(9)°] in [NH4][7,8-(PPh2)2-7,8-C2B9H10]. of this plane with a trans conformation. The average M–
The P=O bond lengths are within a narrow range from O distances are 1.907 and 1.919 Å in complexes 1 and 2,
1.488(4) to 1.525(4) Å, which is basically consistent with respectively, which are slightly shorter than the correspond-
the average values 1.528 Å in H[7,8-(OPPh2)2-7,8-C2B9H10], ing values of 2.113 Å in [Cu(dppf)(odppf)]+[45] and 1.968 Å
1.483(5) Å in [Ni{7-(OPPh2)-8-(PPh2)-7,8-C2B9H10}{7,8- in ZnBr2(OPPh3)2.[46] The O–M–O angles in these two com-
(PPh2)2-7,8-C2B9H10}], and 1.486(6) Å in 1-(OPPh2)-2- plexes are almost equal to each other with a value of about
(PPh2)-1,2-C2B10H10.
90°. As M, C(7), and C(8) are all out of the plane O(1)
The structures of complexes 1 and 2 are symmetrical, P(1)P(2)O(2) in the same orientation, a boat conformation
with the MII (M = Cu, Zn) atom as the symmetry center. between the seven atoms of the chelating ring between the
Symmetry transformations used to generate equivalent ligand and the metal is formed, in which the O(1)P(1)P(2)
atoms are –x+1, –y+1, –z for 1 and –x+1, –y+1, –z+2 for O(2) plane can be used as the bottom of the boat.
2. The bis(phosphoryl) ligand [7,8-(OPPh2)2-7,8-C2B9H10]–
As shown in Figure 3, the crystal structure of the com-
is coordinated in a bidentate fashion through the O atoms plex 3 is a little different from the above two complexes.
to the MII ion. The MII and four oxygen atoms can form a Although the two bis(phosphoryl) ligands are still coordi-
perfect plane in complexes 1 and 2, and the O(1), M, O(1) nated in a bidentate fashion to the Ni atom, and a plane is
# and O(2), M, O(2)# (# denotes the equivalent atom gen- also formed by the four oxygen atoms, the coordination
erated by symmetry) are in an ideal line. The two bis(phos- sphere of the Ni atom has been changed by one tetra-
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Synthesis and Crystal Structure of Five Carborane Compounds
FULL PAPER
(100.63 MHz, CDCl3): δ = 25.212–135.856 (48 C, Aryl-C), 77.101
(4 C, Ccage) ppm. C52H60B18CuO4P4 (1131.00): calcd. C 55.22, H
5.35; found C 55.30, H 5.38.
hydrofuran molecule whose oxygen atom is coordinated to
the NiII atom. The Ni atom is therefore out of the plane by
0.1884 Å, positioned towards the fifth Ni–O bond. There-
fore, the coordination sphere of the metal atom should be
characterized as a square pyramid, different from the
square-planar coordination mode in complexes 1 and 2.
Another difference is the P–O–M angles in the seven-mem-
bered ring formed by two P, two O, two Ccage atoms and
the Ni atom. These two angles in complex 3 are 141.4(2)
and 161.7(2)°, respectively, whereas there is no noticeable
difference between these two angles in complexes 1 and 2.
In complex 3, the five Ni–O bond lengths are almost equal
to each other within a narrow range 1.992(4)–2.011(3) Å,
which is obviously shorter than the average value of 2.112 Å
in [Ni{CH2(OPPh2)2}3(ClO4)2]·CH3OH.[47]
Synthesis of [Zn{7,8-(OPPh2)2-7,8-C2B9H10}2] (2): ZnCl2 (13.6 mg,
0.10 mmol) and 1,2-(PPh2)2-1,2-C2B10H10 (51.2 mg, 0.10 mmol)
were mixed in ethanol (10 mL, 95%). The stirring process was con-
tinued for about 6 h in air at room temperature. The white solid
was filtered off and dried in vacuo (19.7 mg, 34.78%). M.p. Ͼ
300 °C (dec.). A suitable crystal for X-ray diffraction was obtained
from a dichloromethane solution after partial evaporation of the
solvent. FT-IR: νKBr = 3100 (m), 2557 (m), 1625 (s), 1454 (m), 1263
˜
(s), 1120 (m), 735 (m), 690 (s), 510 (m) cm–1. 1H NMR
(400.15 MHz, CDCl3): δ = 7.284–7.563 (40 H, Aryl-H), –2.301 (2
H, B–H–B) ppm. 13C NMR (100.63 MHz, CDCl3): δ = 23.421–
136.000 (48 C, Aryl-C), 76.863 (4 C, Ccage) ppm. C52H60B18O4P4Zn
(1132.83): calcd. C 55.13, H 5.34; found C 55.10, H 5.30.
Synthesis of [Ni{7-(OPPh2)-8-(PPh2)-7,8-C2B9H10}{7,8-(PPh2)2-
7,8-C2B9H10}]: NiCl2·6H2O (23.8 mg, 0.10 mmol) and 1,2-(PPh2)2-
1,2-C2B10H10 (51.2 mg, 0.10 mmol) were mixed in ethanol (10 mL,
95%). The stirring process was continued for about 6 h at room
Conclusions
In this work, we reported two free compounds with a temperature in air, and then the yellow solid was filtered off,
washed with ethanol, and dried in vacuo (27.5 mg, 51.01%). M.p.
207–208 °C. A single crystal for X-ray diffraction was grown from
closo- or nido-carborane skeleton and three new metal–car-
borane complexes containing the bis(phosphoryl)-nido-car-
borane ligand, which were obtained by the reactions of the
closo ligand 1,2-(PPh2)2-1,2-C2B10H10 with some inorganic
metal compounds in air. The obtainment of the two free
bis(phosphoryl)carborane compounds could give us some
information for understanding the oxidation and degrada-
tion of the closo ligand in air. The results obtained from this
paper and our recent work[38] indicated that the oxidation
process occurs before the partial degradation, and that the
oxidation of the two phosphorus atoms is not synchronous.
a dichloromethane/n-hexane solution. FT-IR: ν
= 3000 (m),
˜
KBr
2545 (m), 1475 (m), 1250 (s), 730 (m) cm–1. 1H NMR (400.15 MHz,
CDCl3): δ = 7.20–7.58 (40 H, Aryl-H); –2.24 (2 H, B–H–B) ppm.
13C NMR (100.63 MHz, CDCl3): δ = 125.913–134.942 (48 C, Aryl-
C); 76.198 (4 C, Ccage) ppm. C52H60B18NiOP4 (1078.17): calcd. C
57.92, H 5.61; found C 57.85, H 5.55.
Synthesis
of
[Ni(thf){7,8-(OPPh2)2-7,8-C2B9H10}2]·thf
(3):
NiCl2·6H2O (23.8 mg, 0.10 mmol) was added to a suspension of
1,2-(PPh2)2-1,2-C2B10H10 (51.2 mg, 0.10 mmol) in ethanol (10 mL,
95%). After the mixture was stirred for 12 h in air at room tempera-
ture, the yellow solid was filtered off, washed with ethanol, and
dried in vacuo (18.4 mg, 32.68%). M.p. 198–199 °C. A single crys-
tal suitable for X-ray analysis was obtained from a tetrahydrofuran
Experimental Section
solution after partial evaporation of the solvent. FT-IR: ν
=
˜
KBr
Materials and Measurements: All reactions and subsequent manip-
ulations were carried out in air. 1,2-bis(diphenylphosphanyl)-1,2-
dicarba-closo-dodecaborane(10) was prepared according to the lit-
erature procedure.[48] All chemicals were purchased and used as
received. Infrared spectra were recorded in the range 400–
4000 cm–1 from KBr pellets with a Nicolet-460 FT-IR spectropho-
tometer. Elemental analysis (C, H) was carried out with a Perkin–
3120 m, 2540 (m), 1689 (s), 1425 (m), 1260 (s), 1078 (m), 725 (m),
680 (s), 490 (m) cm–1. 1H NMR (400.15 MHz, CDCl3): δ = 7.187–
7.594 (40 H, Aryl-H), –2.222 (2 H, B–H–B) ppm. 13C NMR
(100.63 MHz, CDCl3): δ = 26.334–139.114 (48 C, Aryl-C), 77.007
(4 C, Ccage) ppm. C60H76B18NiO6P4 (1270.38): calcd. C 56.72, H
6.03; found C 56.67, H 5.98.
Synthesis of [1-(OPPh2)-2-(PPh2)-1,2-C2B10H10] (4): 1,2-(PPh2)2-
1,2-C2B10H10 (51.2 mg, 0.10 mmol) was added to ethanol (10 mL,
95%). The suspension was stirred for 8 h; air was continuously and
slowly bubbled into the mixture at room temperature. The white
solid was filtered off and dried in vacuo (36.5 mg, 69.06%). M.p.
232–233 °C. A single crystal suitable for X-ray analysis was ob-
1
Elmer 2400 II elemental analyzer. The H and 13C-NMR were re-
corded with a Varian Mercury 400 spectrometer in CDCl3 solution,
with tetramethylsilane (TMS) as the internal standard, at 400.15
and 100.63 MHz, respectively. The 13C spectra are broadband pro-
ton decoupled. The chemical shifts are reported in parts per million
with respect to the references and are stated relative to external
tained from a dichloromethane/n-hexane solution. FT-IR: ν
=
˜
KBr
1
TMS for H and 13C NMR spectroscopy.
3045 (m), 2510 (m), 1669 (s), 1415 (m), 1250 (s), 1083 (m), 707 (m),
672 (s), 510 (m) cm–1. 1H NMR (400.15 MHz, CDCl3): δ = 7.057–
7.784 (20 H, Aryl-H) ppm. 13C NMR (100.63 MHz, CDCl3): δ =
Synthetic Procedures
Synthesis of [Cu{7,8-(OPPh2)2-7,8-C2B9H10}2] (1): To a suspension
of 1,2-(PPh2)2-1,2-C2B10H10 (51.2 mg, 0.10 mmol) in ethanol
(10 mL, 95%) was added CuCl2·2H2O (17.1 mg, 0.10 mmol). The
mixture was stirred for about 6 h in air at room temperature. The
25.886–137.553 (24 C, Aryl-C), 76.825 (2 C, Ccage
) ppm.
C26H30B10OP2 (528.54): calcd. C 59.08, H 5.72; found C 59.11, H
5.80.
blue solid formed was filtered off and dried in vacuo (20.9 mg, Synthesis of H[7,8-(OPPh2)2-7,8-C2B9H10]·0.25C2H5OH (5): In a
36.96%). M.p. 215–216 °C. A suitable crystal for X-ray diffraction manner similar to the procedure for the preparation of compound
was grown from a dichloromethane/n-hexane solution. FT-IR: ν
4, the mixture was stirred for 18 h. The white solid was filtered off
˜
KBr
= 3090 (m), 2550 (m), 1670 (s), 1400 (m), 1255 (s), 1100 (m), 756 and dried in vacuo (46.4 mg, 84.94%). M.p. 208–209 °C. A suitable
(m), 660 (s), 530 (m) cm–1. 1H NMR (400.15 MHz, CDCl3): δ = crystal for X-ray diffraction was grown from a dichloromethane
7.128–7.400 (40 H, Aryl-H); –2.312 (2 H, B–H–B) ppm. 13C NMR solution layered with n-hexane. FT-IR: νKBr = 3050 (m), 2520 (m),
˜
Eur. J. Inorg. Chem. 2007, 53–59
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
57

J. M. Dou, D. P. Zhang, D. C. Li, D. Q. Wang
FULL PAPER
Table 2. Details of the crystal parameters, data collections and refinements for 1–5.
Crystal data
1
2
3
4
5
Empirical formula
Formula weight
Temperature [K]
Wavelength [Å]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
C52H60B18CuO4P4 C52H60B18O4P4Zn
C60H76B18O6P4Ni C26H30B10OP2
C26.5H32.5B9O2.25P2
546.26
298(2)
1131.00
298(2)
1132.83
298(2)
1270.38
298(2)
528.54
298(2)
0.71073
monoclinic
P21/n
0.71073
triclinic
0.71073
triclinic
0.71073
triclinic
0.71073
triclinic
¯
P1
¯
P1
¯
P1
¯
P1
11.576(4)
12.774(4)
13.332(4)
101.423(5)
109.229(5)
1670.1(9)
1
11.568(4)
12.748(4)
13.318(4)
101.203(5)
109.358(5)
1661.4(9)
1
13.990(3)
15.389(3)
20.441(4)
93.069(3)
96.878(3)
3884.2(12)
2
16.438(4)
10.423(2)
17.739(4)
90
111.868(3)
2820.6(11)
4
11.424(3)
11.714(3)
13.559(4)
95.401(5)
108.386(4)
1597.1(8)
2
0.160
1.136
1206
β [°]
V [Å3]
Z
Absorption coefficient [mm–1]
D [Mg·m–3]
F(000)
0.461
0.505
0.374
0.175
1.125
583
1.132
584
1.086
1324
1.245
1096
Crystal size [mm]
Theta range [°]
Limiting indices
0.35ϫ0.32ϫ0.29 0.23ϫ0.21ϫ0.19
0.46ϫ0.40ϫ0.20 0.55ϫ0.50ϫ0.48 0.35ϫ0.31ϫ0.29
2.09 to 25.01
–13 Յ h Յ 13
–15 Յ k Յ 15
–8 Յ l Յ 15
5663
2.04 to 25.01
–9 Յ h Յ 13
–15 Յ k Յ 15
–15 Յ l Յ 15
5573
1.97 to 25.01
–16 Յ h Յ 14
–18 Յ k Յ 18
–19 Յ l Յ 24
13040
2.37 to 25.01
–19 Յ h Յ 15
–9 Յ k Յ 12
–21 Յ l Յ 20
4921
2.92 to 25.01
–13 Յ h Յ 13
–13 Յ k Յ 13
–10 Յ l Յ 16
5492
Independent reflection
Max. and min. transmission
Goodness-of-fit on F2
R [IϾ2σ(I)]
0.8778 and 0.8552 0.9102 and 0.8928 0.9290 and 0.8468 0.9206 and 0.9097 0.9551 and 0.9461
1.009
1.003
1.002
1.007
1.010
R1 = 0.0790
wR2 = 0.1825
R1 = 0.1616
wR2 = 0.2264
R1 = 0.0715
wR2 = 0.1755
R1 = 0.1375
wR2 = 0.2237
R1 = 0.0781
wR2 = 0.1894
R1 = 0.1588
wR2 = 0.2482
R1 = 0.0616
wR2 = 0.1678
R1 = 0.0917
wR2 = 0.2093
R1 = 0.0762
wR2 = 0.1777
R1 = 0.1492
wR2 = 0.2193
0.584 and –0.287
R (all data)
Largest diff. peak and hole
1.067 and –0.514 1.356 and –0.406
1.135 and –0.423 0.894 and –1.186
(ϫ102 electrons Å–3)
1669 (s), 1400 (m), 1260 (s), 1085 (m), 700 (m), 660 (s), 510 (m)
cm–1. 1H NMR (400.15 MHz, CDCl3): δ = 7.206–7.598 (20 H,
Aryl-H); –2.105 (1 H, B–H–B) ppm. 13C NMR (100.63 MHz,
Acknowledgments
This work was supported by the National Natural Science Founda-
tion of the P. R. China (project no. 20371025) and Open Research
Fund Program of the Key Laboratory of Marine Drugs (Ocean
University of China), Ministry of Education [project no. KLMD
(OUC) 2004].
CDCl3): δ = 22.300–135.198 (24 C, Aryl-C), 76.887 (2 C, Ccage
)
ppm. C26.5H32.5B9O2.25P2 (546.26): calcd. C 58.26, H 5.99; found C
58.31, H 5.96.
X-ray Structure Determination
The collections of the crystallographic data for the three carborane
complexes and two carborane compounds were carried out with a
Bruker Smart-1000 CCD diffractometer, by using graphite-mono-
chromatized Mo-Kα (λ = 0.71073 Å) at 298(2) K. The structures
were solved by direct methods and expanded by using Fourier dif-
ference techniques with the SHELXTL-97 program package.[49]
The solvent content in compound 5 is disordered. Partially occu-
pied atoms of the solvent molecule were refined with isotropic dis-
placement parameters, but the rest of the non-hydrogen atoms were
refined anisotropically by full-matrix least-squares calculations on
F2. All the H atoms were located in a difference Fourier map and
thereafter refined isotropically, except the H atoms of the solvent
C2H5OH of compound 5. The bridging H atoms of the nido carbor-
ane skeleton were refined isotropically with fixed U. Details of the
crystal parameters, data collection, and refinement are summarized
in Table 2.
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Eur. J. Inorg. Chem. 2007, 53–59

Synthesis and Crystal Structure of Five Carborane Compounds
FULL PAPER
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Received: July 20, 2006
Published Online: November 17, 2006
Eur. J. Inorg. Chem. 2007, 53–59
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
59