Synthesis and characterization of mono- and dinuclear nickel complexes with dichalcogenolate o-carboranyl ligands

Article abstract of DOI:10.1016/j.ica.2003.05.001

Three mono- and dinuclear nickel complexes with dichalcogenolate o-carboranyl ligands were synthesized and characterized by X-ray crystallography. The reactions of Ni(COD)₂(COD=1,5-octadiene) with [(THF)₃LiE₂C₂B

Full text of DOI:10.1016/j.ica.2003.05.001

Inorganica Chimica Acta 357 (2004) 361–366
www.elsevier.com/locate/ica
Synthesis and characterization of mono- and dinuclear
nickel complexes with dichalcogenolate o-carboranyl ligands
b
Xiao-Yan Yu , Shi-Xiang Lu , Guo-Xin Jin
b
a,b,
a
*, Lin-Hong Weng
a
Department of Chemistry, Fudan University, Shanghai 200433, PR China
b
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences,
Changchun 130022, PR China
Received 13 January 2003; accepted 12 May 2003
Abstract
Three mono- and dinuclear nickel complexes with dichalcogenolate o-carboranyl ligands were synthesized and characterized by
X-ray crystallography. The reactions of Ni(COD)2(COD ¼ 1,5-octadiene) with [(THF)3LiE2C2B10H10Li(THF)]2 (E ¼ S, Se) in THF in
the presence of air in different ratios afforded the mono- and dinuclear nickel complexes of formulae Li(THF)4]2[Ni(E2C2B10H10)2]
(E ¼ S, 1a; E ¼ Se, 1b) and [Li(THF)4]2[Ni2(E2C2B10H10)3] (E ¼ S, 2a; E ¼ Se, 2b). In 2a, two nickel atoms are connected by one
chalcogen (g1,g2-S2C2B10H10) bridging ligand with strong metal-metal interaction. Complex of formula (PPh3)2Ni(S2C2B10H10)
ꢀ 0.5THF (3a) was also obtained from the reaction of (PPh3)2NiCl2 and [(THF)3LiS2C2B10H10Li(THF)]2.
Ó 2003 Elsevier B.V. All rights reserved.
Keywords: Nickel complexes; Crystal structures; Dichalcogenolate o-carborane
1. Introduction
vestigate the syntheses and characterization of nickel
complexes with dichalcogenolate o-carboranyl ligands.
In previous paper [11], we have described the synthesis
and characterization of dilithium dichalcogenolate car-
boranes. The molecular structure analysis indicated that
dilithium dichalcogenolate carboranes are dimers with
the formula [(THF)3LiE2C2B10H10Li(THF)]2 (E ¼ S, Se).
In this paper, several mono- and dinuclear nickel com-
plexes containing dichalcogenolate o-carboranyl ligands
(Scheme 1) were obtained from the reactions of nickel
complexes and dilithium dichalcogenolate o-carborane.
Among them three complexes were crystallographically
studied.
Up to date considerable attention has been devoted
to the metal complexes with chalcogenolate ligands. The
square planar complexes of nickel with bidentate chal-
cogenolate ligands were used for special purpose, such
as reversible olefin seperation and purification, etc. [1].
On the other hand, transition metal complexes con-
taining a chelating 1,2-dicarba-closo-dodecabarane-1,2-
dichalcogenolate ligands [2–9] have attracted a great
deal of interest to take advantage of the unique molec-
ular structure of carborane in recent years. So nickel
complexes with dichalcogenolate o-carboranyl ligands
are expected to have interesting structures and unique
properties. Although there are some reports of mono-
nuclear nickel complexes with carboranyl ligands and
their derivatives [10], comparable X-ray structures of
nickel complexes with chalcogenolate carboranyl li-
gands are so far unknown. These prompted us to in-
2. Experimental
2.1. General experimental information
All the reactions and the manipulations were routinely
carried out under pure argon atmosphere using the stan-
dard Schlenk technique. The use of dry and oxygen-free
solvents is necessary. [(THF)3LiE2C2B10H10Li(THF)]2
* Corresponding author. Tel.: +86-81-21-65641740; fax: +86-8121-
65643776.
E-mail address: gxjin@fudan.edu.cn (G.-X. Jin).
0020-1693/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2003.05.001

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X.-Y. Yu et al. / Inorganica Chimica Acta 357 (2004) 361–366
Scheme 1. Synthesis of Ni dichalcogenolate complexes.
(E ¼ S, Se) was synthesized according to the procedures
described in our another paper [11]. The starting materials
Ni(COD)2 (COD ¼ 1,5-octadiene) were prepared ac-
cording to the literature [12]. Infrared spectra were mea-
sured on a Bio-Rad FTS135 spectrometer as a KBr pellet.
Elemental analyses were carried out by the Analytic
Center of Changchun Institute.
toluene and then the white precipitate was removed by
centrifugation. Brown precipitate was given by the re-
moval of the solvent. Recrystallization from a THF/
hexane solution resulted in the isolation of brown block
crystals. Yield: 0.230 g (73.6%). Anal. Calc. for
C36H84B20Li2NiO8Se4: C, 34.60; H, 6.78. Found: C,
34.93; H, 7.25%. IR (KBr, cmꢁ1): t
¼ 2592, 2568
ðB–HÞ
cmꢁ1
.
2.2. Preparation of [Li(THF)4]2[Ni(S2C2B10H10)2]
(1a)
2.4. Preparation of [Li(THF)4]2[Ni2(S2C2B10H10)3]
(2a)
A solution containing Ni(COD)2 (0.069 g, 0.25
mmol) and [(THF)3LiS2C2B10H10Li(THF)]2 (0.254 g,
0.25 mmol) in 20 ml THF was kept stirring at room
temperature in air for two days. After the removal of
solvent under vacuum, the resident was extracted by
toluene and then the white precipitate was removed by
centrifugation. Brown precipitate was given by the re-
moval of the solvent. Recrystallization from a THF/
hexane solution resulted in the isolation of brown block
crystals. Yield: 0.231 g (87.1%). Anal. Calc. etc., for
C36H84B20Li2NiO8S4: C, 40.71; H, 7.97. Found: C,
A solution containing Ni(COD)2 (0.069 g, 0.25
mmol) and [(THF)3LiS2C2B10H10Li(THF)]2 (0.142 g,
0.14 mmol) in 20 ml THF was kept stirring at room
temperature in air for two days. After the removal of
solvent under vacuum, the resident was extracted by
toluene and then the white precipitate was removed by
centrifugation. Black precipitate was given by the re-
moval of the solvent. Recrystallization from a THF/
hexane solution resulted in the isolation of black block
crystals. Yield: 0.093 g (55.1%). Anal. Calc. for
C38H96B30Li2Ni2O9S6: C, 33.93; H, 7.19. Found: C,
41.28; H, 7.53%. IR (KBr, cmꢁ1): t
¼ 2592, 2568
ðB–HÞ
cmꢁ1
.
33.57; H, 7.66%. IR (KBr, cmꢁ1): t
¼ 2592, 2573
ðB–HÞ
cmꢁ1
.
2.3. Preparation of [Li(THF)4]2[Ni(Se2C2B10H10)2]
(1b)
2.5. Preparation of [Li(THF)4]2[Ni2(Se2C2B10H10)3]
(2b)
A solution containing Ni(COD)2 (0.069 g, 0.25
mmol) and [(THF)3LiSe2C2B10H10Li(THF)]2 (0.301 g,
0.25 mmol) in 20 ml THF was kept stirring at room
temperature in air for two days. After the removal of
solvent under vacuum, the resident was extracted by
A solution containing Ni(COD)2 (0.069 g, 0.25
mmol) and [(THF)3LiSe2C2B10H10Li(THF)]2 (0.170 g,
0.14 mmol) in 20 ml THF was kept stirring at room
temperature in air for two days. After the removal of

X.-Y. Yu et al. / Inorganica Chimica Acta 357 (2004) 361–366
363
solvent under vacuum, the resident was extracted by
toluene and then the white precipitate was removed by
centrifugation. Black precipitate was given by the re-
moval of the solvent. Recrystallization from a THF/
hexane solution resulted in the isolation of black block
crystals. Yield: 0.103 g (50.6%). Anal. Calc. for
C38H96B30Li2Ni2O9Se6: C, 28.06; H, 5.95. Found: C,
2.7. Structure solution and refinement for complexes 1a,
2a and 3a
For complexes 1a, 2a and 3a, a single crystal of each
suitable for X-ray was sealed into a glass capillary, re-
spectively, and mounted on a diffractometer. The inten-
sity data of all the single crystals were collected on the
CCD-Bruker Smart APEX system. All the determina-
tions of unit cell and intensity data were performed with
graphite monochromated Mo Ka radiation (k ¼ 0:71073
27.84; H, 5.48%. IR (KBr, cmꢁ1): t
¼ 2592, 2573
ðB–HÞ
cmꢁ1
.
ꢀ
2.6. Preparation of (PPh3)2Ni(S2C2B10H10) ꢀ 0.5THF
(3a)
A). All the data were collected at room temperature using
the x scan technique. These structures were solved by the
direct methods, expanded using Fourier techniques and
refined on F 2 by a full-matrix least-squares method. The
non-hydrogen atoms were refined anisotropically and
hydrogen atoms were included but not refined. All the
calculations were carried out with Siemens SHELXTL
PLUS program. Details of crystal data for complexes 1a,
2a and 3a are summarized in Table 1.
A suspension containing (PPh3)2NiCl2 [13] (0.206 g,
0.30 mmol) and [(THF)3LiS2C2B10H10Li(THF)]2 (0.301
g, 0.30 mmol) in 20 ml THF was kept stirring at room
temperature for 24 h. After the removal of solvent under
vacuum, the resident was washed by hexane and ex-
tracted by toluene. And then the white precipitate was
removed by centrifugation. Black precipitate was given
by the removal of the solvent. Recrystallization from a
THF/hexane solution resulted in the isolation of black
needle crystals. Yield: 0.237 g (80.0%). Anal. Calc. for
C38H40B10Ni1P2S2: C, 57.80; H, 5.11. Found: C, 58.24;
3. Results and discussion
Reactions of Ni(COD)2 with two equivalent amounts
of [(THF)3LiE2C2B10H10Li(THF)]2 in THF in air at
H, 5.36%. IR (KBr, cmꢁ1): t
¼ 2583 cmꢁ1
.
ðB–HÞ
Table 1
Crystallographic data for complexes 1a, 2a and 3a
Complex
1a
2a
3a
Color
Habit
Formula
dark brown
block
black
block
black
block
C36H84B20Li2NiO8S4
C38H96B30Li2Ni2O9S6
1345.11
C40H44B10NiP2S2O0:5
825.62
Formula weight
Cryst size (mm)
Cryst system
Space group
1062.06
0.70 ꢂ 0.25 ꢂ 0.10
monoclinic
C2=c
29.833(12)
9.978(4)
22.106(9)
90
0.40 ꢂ 0.35 ꢂ 0.25
triclinic
0.25 ꢂ 0.20 ꢂ 0.15
monoclinic
C2=c
17.675(9)
P ꢁ 1
ꢀ
a (A)
13.542(4)
13.566(4)
ꢀ
b (A)
21.508(11)
23.729(12)
ꢀ
c (A)
21.746(7)
76.392(4)
a (°)
b (°)
c (°)
90
107.020(7)
115.280(5)
90
88.596(4)
70.999(4)
3665(2)
90
8626(7)
3
ꢀ
V (A )
5950(4)
4
1.186
Z
2
1.219
8
1.272
DCalc: (mg/m3)
F (000)
2248
1.95–26.01
1408
1.82–25.01
3424
1.89–25.01
h range (°)
Index ranges
ꢁ34 6 h 6 36, ꢁ12 6 k 6 12,
ꢁ27 6 l 6 17
ꢁ16 6 h 6 15, ꢁ16 6 k 6 16,
ꢁ24 6 l 6 25
0.727
ꢁ16 6 h 6 21,
ꢁ25 6 k 6 25,ꢁ28 6 l 6 19
6.51
17765
Absorption coefficient (mmꢁ1
Reflections collected
Independent reflections
Refinement methods
Data/restraints/parameters
Final R indices [I > 2r(I)]
R indices (all data)
)
0.508
13016
15527
5807 (Rint ¼ 0:0403)
full-matrix least-squares on F 2
5807/0/362
12642 (Rint ¼ 0:0381)
full-matrix least-squares on F 2
12642/11/912
R1 ¼ 0:0774, wR2 ¼ 0:1619
R1 ¼ 0:1521, wR2 ¼ 0:2051
1.063
7594 (Rint ¼ 0:0620)
full-matrix least-squares on F 2
7594/3/545
R1 ¼ 0:0640, wR2 ¼ 0:1536
R1 ¼ 0:0999, wR2 ¼ 0:1784
1.058
R1 ¼ 0:0705, wR2 ¼ 0:1308
R1 ¼ 0:1127, wR2 ¼ 0:1479
1.153
GOF on F 2
ꢀ
Largest diff. peak and hole e A
ꢁ3
0.465 and )0.313
0.546 and )0.278
0.594 and )0.328

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X.-Y. Yu et al. / Inorganica Chimica Acta 357 (2004) 361–366
room temperature afforded the mononuclear complexes
of formula [Ni(E2C2B10H10)2][Li(THF)4]2 (E ¼ S, 1a;
E ¼ Se, 1b), after removal of the solvent, extraction with
toluene, and recrystallization from a THF/hexane solu-
tion. On the other hand, Ni(COD)2 reacted with one and a
half equivalent amounts of [(THF)3LiE2C2B10H10
Li(THF)]2 in THF in air to give dinuclear compounds of
formula and [Ni2(E2C2B10H10)3][Li(THF)4]2 (E ¼ S, 2a;
E ¼ Se, 2b). Complex of formula (PPh3)2Ni(S2C2B10H10)
(3a) was also obtained from the reaction of (PPh3)2NiCl2
and [(THF)3LiS2C2B10H10Li(THF)]2. These complexes
are soluble in polar organic solvents such as THF and
toluene but insoluble in non-polar solvents such as hex-
ane. Their IR spectra show a typical strong and broad
characteristic B–H absorption at about 2570 cmꢁ1, which
is consistent with the previous reported complexes with
carboranyl ligands [6–8].
and the nickel atom are 85.59(4) and 94.41(4)°, close to
90°.
Black crystals of 2a were obtained from recrystalli-
zation of THF/Hexane and characterized crystallo-
graphically. Fig. 2 exhibits the anionic moiety structure
of complex 2a. In 2a, the two nickel(II) atoms are
bridged by two l3-sulfur atoms of one dithio-carborane
to afford a dinuclear structure with strong metal–metal
interaction. Each nickel atom is bonded to two l2-sulfur
atoms of one dithio-carborane and to two l3-bridging
sulfur atoms of one dithio-carborane. The bridging
sulfur atom is bonded to the carbon atom of the carb-
oranyl ligand and to two nickel metals in a slightly
distorted trigonal atmosphere. The two nickel atoms
and two bridging sulfur atoms form a distorted tetra-
hedron. Three dithio-carboranes are located around two
nickel atoms to form a triangular sphere.
As shown in Scheme 1, complexes 1a, 1b, 2a and 2b can
also be directly synthesized by the reactions between
NiCl2 and [(THF)3LiE2C2B10H10Li(THF)]2 (E ¼ S, Se) in
different ratios. Adding excess of [(THF)3LiE2C2B10H10
Li(THF)]2 to complex 2a (2b) leads to the formation of
compound 1a (1b). Complex 1a can also be obtained from
3a and [(THF)3LiS2C2B10H10Li(THF)]2. However, at-
tempts to obtain 2a from 3a were not successful.
Recrystallization of 1a from a THF/hexane solution
resulted in the isolation of some dark brown crystals
which were identified as [Li(THF)4]2[Ni(S2C2B10H10)2]
by X-ray analysis. The anionic moiety of complex 1a is
shown in Fig. 1, together with the atomic labeling
scheme. Complex 1a has a center of symmetry at the
nickel atom. The molecular structure of 1a consists of
two well-separated, alternating layers of the discrete
tetrahedral cations [Li(THF)4]þ and the complex anion
[Ni(S2C2B10H10)2]2ꢁ. In the anion, the Ni2þ ion is co-
ordinated to four l2-sulfur atoms of two dithio-car-
boranes in a distorted square planar arrangement. In
complex 1a, the bond distances of Ni(1)–S(1) and Ni(1)–
In complex 2a, to metal Ni(1), the respective bond
distances of Ni(1)–S(1) and Ni(1)–S(2) between the
nickel atom and the bridging l3-sulfur atom are
2.2410(19) and 2.2504(14) A, much longer than the
Ni(1)–S(3) and Ni(1)–S(4) bond distances of 2.153(2)
ꢀ
ꢀ
and 2.1599(19) A between the nickel atom and the l2-
sulfur atom. The similar situation is found around Ni(2)
atmosphere. The S(1)–C(1) and S(2)–C(2) lengths of
ꢀ
1.797(6) and 1.800(6) A are slightly longer than the av-
ꢀ
erage S–C distance of 1.776(7) A between the l2-sulfur
and carbon atom and those normally observed for
compounds with dithio-carboranes [14]. The distance
ꢀ
between the two nickel atoms is 2.6559(14) A. The four
sulfur atoms around each nickel atom form a distorted
square plane with the angles between adjacent sulfur
atoms and the nickel atom close to 90°.
Fig. 3 illustrates the molecular structure of complex
(PPh3)2Ni(S2C2B10H10) ꢀ 0.5THF (3a). The nickel atom
ꢀ
S(2) are 2.1875(12) and 2.1776(11) A, respectively. The
respective S(1)–C(1) and S(2)–C(2) lengths are 1.779(3)
ꢀ
and 1.771(3) A, which are comparable to those normally
observed for compounds with dithio-carboranes [6,7].
The S–Ni–S angles between the adjacent sulfur atoms
Fig. 1. Anionic structure of complex [Ni(S2C2B10H10)2][Li(THF)4]2
(1a) (The hydrogen atoms are omitted for clarity).
Fig. 2. Structure of complex [Ni2(S2C2B10H10)3][Li(THF)4]2 (2a) (hy-
drogen atoms are omitted for clarity).

X.-Y. Yu et al. / Inorganica Chimica Acta 357 (2004) 361–366
365
Table 3
ꢀ
Selected bond lengths (A) and angles (°) for complex 2a
Ni(1)–S(1)
Ni(1)–S(3)
Ni(2)–S(1)
Ni(2)–S(5)
S(1)–C(1)
2.2504(19) Ni(1)–S(2)
2.153(2) Ni(1)–S(4)
2.2410(19)
2.1599(19)
2.229(2)
2.152(2)
1.800(6)
1.781(6)
1.776(7)
1.957(14)
1.934(15)
1.92(2)
2.2458(19) Ni(2)–S(2)
2.1646(19) Ni(2)–S(6)
1.797(6)
1.767(7)
1.780(7)
S(2)–C(2)
S(4)–C(12)
S(6)–C(22)
S(3)–C(11)
S(5)–C(21)
Ni(1)–Ni(2)
Li(1)–O(2)
Li(1)–O(4)
Li(2)–O(6)
Li(2)–O(8)
2.6559(14) Li(1)–O(1)
1.941(15)
1.911(14)
1.94(2)
Li(1)–O(3)
Li(2)–O(5)
Li(2)–O(7)
1.97(3)
1.99(3)
S(3)–Ni(1)–S(4)
S(4)–Ni(1)–S(2)
S(4)–Ni(1)–S(1)
S(3)–Ni(1)–Ni(2)
S(2)–Ni(1)–Ni(2)
S(6)–Ni(2)–S(5)
S(5)–Ni(2)–S(2)
S(5)–Ni(2)–S(1)
S(6)–Ni(2)–Ni(1)
C(1)–S(1)–Ni(2)
S(2)–Ni(2)–Ni(1)
Ni(2)–S(1)–Ni(1)
C(2)–S(2)–Ni(1)
96.49(7)
174.39(8)
91.24(7)
118.88(7)
53.33(5)
95.78(7)
170.69(8)
90.15(7)
122.31(7)
99.8(2)
S(3)–Ni(1)–S(2)
S(3)–Ni(1)–S(1)
S(2)–Ni(1)–S(1)
S(4)–Ni(1)–Ni(2)
S(1)–Ni(1)–Ni(2)
S(6)–Ni(2)–S(2)
S(6)–Ni(2)–S(1)
S(2)–Ni(2)–S(1)
S(5)–Ni(2)–Ni(1)
C(1)–S(1)–Ni(1)
S(1)–Ni(2)–Ni(1)
C(2)–S(2)–Ni(2)
Ni(2)–S(2)–Ni(1)
88.51(7)
171.66(8)
83.64(6)
121.54(6)
53.71(5)
90.02(7)
174.05(8)
84.03(7)
116.94(6)
98.9(2)
Fig. 3. Structure of complex (PPh3)2Ni(S2C2B10H10) (3a) (hydrogen
atoms are omitted for clarity).
53.76(5)
72.41(6)
98.8(2)
53.87(5)
100.7(2)
72.91(6)
Table 2
ꢀ
Selected bond lengths (A) and angles (°) for complex 1a
Ni(1)–S(1)
Ni(1)–S(1A)
S(1)–C(1)
2.1875(12)
2.1875(12)
1.779(3)
1.651(5)
1.920(8)
1.919(8)
Ni(1)–S(2)
Ni(1)–S(2A)
S(2)–C(2)
2.1776(11)
2.1776(11)
1.771(3)
Table 4
Selected bond lengths (A) and angles (deg) for complex 3a
C(1)–C(2)
Li(1)–O(2)
Li(1)–O(4)
Li(1)–O(1)
Li(1)–O(3)
1.939(8)
1.921(8)
ꢀ
Ni(1)–S(1)
Ni(1)–P(1)
S(1)–C(1)
2.2022(16) Ni(1)–S(2)
2.2257(16) Ni(1)–P(2)
2.1738(16)
2.2470(16)
1.782(5)
S(2A)–Ni–S(2) 180.00(5)
S(2A)–Li–S(1)
S(2A)–Ni–S(1A)
S(1)–Ni–S(1A)
C(2)–S(2)–Ni
85.59(4)
94.41(4)
180.0(7)
1.774(5)
S(2)–C(2)
S(2)–Ni–S(1)
S(2)–Ni–S(1A)
C(1)–S(1)–Ni
94.41(4)
85.59(4)
105.20(12)
S(1)–Ni(1)–S(2)
S(1)–Ni(1)–P(2)
S(2)–Ni(1)–P(2)
C(1)–S(1)–Ni(1)
S(1)–C(1)–C(2)
93.30(6)
83.59(6)
S(1)–Ni(1)–P(1)
S(2)–Ni(1)–P(1)
P(1)–Ni(1)–P(2)
171.32(6)
86.92(6)
97.55(6)
105.28(12)
170.22(6)
106.63(16)
115.6(3)
C(2)–S(2)–Ni(1) 106.76(16)
S(2)–C(2)–C(1) 116.4(3)
is coordinated to two P atoms of PPh3 groups and two
sulfur atoms of dithio-carborane in a distorted square
planar arrangement. The average bond distance of Ni–S
Union Road, Cambridge, CB2 1EZ, UK (Fax: +44-
1223-336-033; e-mail: deposit@chemcrys.cam.uk).
ꢀ
is 2.1880(16) A and the average Ni–P length is
ꢀ
2.2364(16) A, not beyond the range in analogous
compounds [15].
Acknowledgements
Selected bond distances and bond angles for com-
plexes 1a, 2a and 3a are listed in Table 2, Table 3 and
Table 4. As far as we know, these are some of the newest
crystal structures of mono- and dinuclear nickel com-
plexes with dichalcogenolate o-carboranyl ligands [10].
Financial Support by the National Natural Science
Foundation of China (29925101) and by the Special
Funds for Major State Basic Research Projects
(G1999064800) is gratefully acknowledged.
4. Supplementary material
References
Crystallographic data (excluding structure factors)
reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supple-
mentary material publication Nos. CCDC-CCDC
199986 – 199988. Copies of the data can be obtained free
of charge on application to The Director, CCDC, 12
[1] K. Wang, E.I. Stiefel, Science 291 (2001) 106.
[2] (a) S. Lu, G.-X. Jin, S. Eibl, M. Herberhold, Y. Xin, Organo-
metallics 21 (2002) 2533;
(b) G.-X. Jin, S. Lu, X.-Y. Yu, The abstract in 20th International
Conference on Organometallic Chemistry, S30, 2002, Corfu,
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