Reactivity differences between nickel and palladium complexes bearing 1,2-diphosphino-1,2-dicarba-dodecaborane ligand

Article abstract of DOI:10.1016/j.jorganchem.2010.08.054

AgOTf (OTf = trifluoromethanesulfonate) shows the reactivity differences when it reacts with carborane complexes [MCl₂{(PPh₂) ₂(C₂B₁₀H₁₀)}] (M = Ni (2), Pd (3)). The reaction of AgOTf with

Full text of DOI:10.1016/j.jorganchem.2010.08.054

Journal of Organometallic Chemistry 696 (2011) 504e511
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Journal of Organometallic Chemistry
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Reactivity differences between nickel and palladium complexes bearing
1,2-diphosphino-1,2-dicarba-dodecaborane ligand
*
Xu-Qiong Xiao, Guo-Xin Jin
Shanghai Key Laboratory of Molecular Catalysis and Innovative Material, Department of Chemistry, Fudan University, Shanghai 200433, China
a r t i c l e i n f o
a b s t r a c t
Article history:
AgOTf (OTf ¼ trifluoromethanesulfonate) shows the reactivity differences when it reacts with carborane
complexes [MCl2{(PPh2)2(C2B10H10)}] (M ¼ Ni (2), Pd (3)). The reaction of AgOTf with the palladium
Received 2 June 2010
Received in revised form
26 August 2010
Accepted 31 August 2010
Available online 6 September 2010
complex 3 affords [Pd2(
between the nickel complex
{(PPh2)2(C2B9H10)}]( -Cl)2[Ag{(PPh2)2(C2B10H10)}] (5) and [Ag2(
m-OTf)2{(PPh2)2(C2B9H10)}2] (4) in high yields, while corresponding reaction
2
and AgOTf leads to the formation of binuclear complexes [Ni
-Cl)2 {(PPh2)2 (C2B10H10)}2] (6). The car-
m
m
borane cage of complexes 4 and 5 were broken to form nido-carboranes. It is believed the group 10
metals themselves play an important role in opening the closo-carborane skeleton. Directly stirring
Keywords:
Carborane
Nickel
Palladium
Molecular structures
Diphosphine ligand
[(PPh2)2(C2B10H10)] with AgOTf afforded [Ag2(
m-OTf)2{(PPh2)2(C2B10H10)}2] (7), which is also used to react
with 2 and 3. The reaction between 2 and 7 gives only 4 in highyields, however, stirring the mixture of 3 and
7 affords [Pd2(m-Cl)2{(PPh2)2(C2B9H10)}2] (8), [Pd{(PPh2)2(C2B9H10)}2] (9) and 6. All these complexes have
been characterized by IR, 1H NMR, 11B NMR and elemental analyses. Complexes 2, 4e9 have also been
determined by single-crystal X-ray diffraction analyses.
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
or platinum dihalogen complexes were usually reacted with silver
salts to extract the halogen ligands first. Then, the products were
In the past few years, many efforts have been made to dicarba-
closo-dodecaborane (1,2-C2B10H12 and the nido-species ([7,8-
used as starting materials to react with pyridine-based ligands to
form supramolecular.
)
C2B9H12]e) due to their strong electron withdrawing ability, steric
bulky effect and extensive electronic delocalization. Transition
metal complexes containing carborane ligands were shown to have
potential applications in many areas, such as boron neutron capture
treatment (BNCT) of tumor [1,2], photophysical properties [3,4],
polymers for high temperature [5], anticancer treatment [6],
supramolecular chemistry, etc [7e11]. The most intensively studied
substituted carboranes are 1,2-dichalocogenolato-1,2-dicarba-
dodecaborane dianions [E2C2(B10H10)]2ꢀ (E ¼ S, Se) [12e18] and 1,2-
diphosphino-1,2-dicarba-dodecaborane ligands [(PR2)2(C2B10H10)]
(R ¼ phenyl, isopropyl, etc.) [19e25].
In this paper [MCl2{(PPh2)2(C2B10H10)}] (M ¼ Ni (2), Pd (3)) are
used to react with AgOTf. These complexes show different reactivity.
The reaction of the palladium complex [PdCl2{(PPh2)2(C2B10H10)}]
(3) with AgOTf affords a binuclear nido-carborane complex [Pd2(m-
OTf)2{(PPh2)2(C2B9H10)}2] (4) in high yields. However, the reaction
of analogous nickel complex [NiCl2{(PPh2)2(C2B10H10)}] (2) with
AgOTf leads to the formation of a heteronuclear complex [Ni
{(PPh2)2(C2B9H10)}](
nuclear complex [Ag2(
of Ag in complexes 5 and 6 indicates there is a Ag complex in the
reaction. [Ag2( -OTf)2{(PPh2)2(C2B10H10)}2] (7) was obtained by the
m-Cl)2[Ag{(PPh2)2(C2B10H10)}] (5) and a homo-
m-Cl)2{(PPh2)2(C2B10H10)}2] (6). The presence
m
The [(PPh2)2(C2B10H10)] ligand, one of the 1,2-diphosphino car-
borane derivatives, is of particular interest because it is structurally
analogous to the cis forms of ethylenediamines, ethylenediphos-
phines, bis(diphenylphosphino) ferrocene, 1,10-(PPh2)2-3,30-Co(1,2-
reaction of [(PPh2)2(C2B10H10)] (1) with AgOTf in high yields.
Complex 7 was also used to react with 2 togive 5 in highyields, while
7 reacts with 3 to produce [Pd2(m-Cl)2{(PPh2)2(C2B9H10)}2] (8), [Pd
{(PPh2)2(C2B9H10)}2] (9) and 6. Complexes 2, 4e9 were confirmed by
C2B9H10 2
)
anion (Scheme 1) [26e32]. These diphosphine ligands
single-crystal X-ray diffraction analyses.
have been widely used in the coordination-driven self-assembly
chemistry [26e31,33,34]. In this field, these diphosphine palladium
2. Results and discussion
The reactions of [(PPh2)2(C2B10H10)] with different nickel
complexes have been demonstrated by Dou et al. [35,36]. For example,
[(PPh2)2(C2B10H10)] reacts with nickel(II) bromide hexahydrate in
* Corresponding author. Tel.: þ86 21 6564 3776; fax: þ86 21 65641740.
E-mail address: gxjin@fudan.edu.cn (G.-X. Jin).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.08.054

X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
505
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
NH2
NH2
Co
Fe
PPh2
(e)
(b)
(a)
(c)
(d)
Scheme 1. Representations of diamine and diphosphine ligands.
ethanol, affording NiBr2[(PPh2)2(C2B10H10)]. However, its analogous
chloride complex cannot be made from the similar condition because
the metal compound itself plays a crucial role, which leads to the
degradation of the closo-carborane skeleton and the forming of
(C2B10H10)] (M ¼ Ni, Pd) in hand, AgOTf was used to extract the
chloride ligands. Treatment of PdCl2[(PPh2)2(C2B10H10)] with 2
equivalent of AgOTf in CH2Cl2 afforded a deboronation production,
complex 4, in 95% yields (Scheme 3). It is interesting that the closo-
carborane cage was broken even in the “safe” non-nucleophilic
solvent. In our previous report, nido-C2B9H10 framework with half-
sandwichgroup 9 metalscanonlybeobtained innucleophilicsolvent
(such as methanol) or using base (such as NaHCO3) [14,43]. Due to the
numerous reported group 10 complexes containing nido-carbrane
ligand and the reported palladium/nickel complex here, it is believed
that not only the solvent and reaction condition but also the group 10
metals themselves play an important role in opening the closo-car-
borane skeleton (vide infra). It is supposed in the first step of this
reaction the chloride was extracted by AgOTf, and then electron
density is transferred from Pd/Ni atoms to the cage [43]. Thus, B(3)/B
(6) of the closo-carborane is susceptible to nucleophilic attack.
Because no nucleophile was used in this reaction, perhaps the elec-
tron density transferring here is enough to partially open the car-
borane cage.
a
deboronation product [Ni(m-Cl){(PPh2)2(C2B9H10)}]2. When Ni
(PPh3)2Cl2 was used as the metal source, NiCl(PPh3)[(PPh2)2(C2B9H10)],
but not NiCl2[(PPh2)2(C2B10H10)], was obtained.
As Teixidor’s group reported [37,38], the reaction of diphos-
phino-closo-carborane with transition metal complexes in nucleo-
philic solvents leads to deboronation of the closo-carborane
skeleton. So the “safe” non-nucleophilic solvent dichloromethane
was used to perform the reaction. By stirring the mixture of
NiCl2(DME) and [(PPh2)2(C2B10H10)] in CH2Cl2 at room temperature,
NiCl2[(PPh2)2(C2B10H10)] was obtained in 91% yields (Scheme 2).
The 1H NMR spectrum of complex 2 shows signals at
7.58e8.48 ppm, which can be attributed to the phenyl group. The
11B NMR spectrum of 2 exhibits signals at
d
d
¼ ꢀ4.7, ꢀ5.6, ꢀ7.0, ꢀ7.9,
ꢀ11.1, ꢀ12.0 ppm, which indicates that the carborane cage is still
closed. The infrared spectrum of complexes 2 in the solid state
exhibits intense BeH stretching of carborane at about 2558 cmꢀ1
.
The structure of complex 2 was confirmed by X-ray diffraction
analyses. The ORTEP diagram of 2 is presented in Fig.1, with selected
bond lengths and angles in the figure caption. The molecular
structure reveals that the geometry at the nickel atom is slightly
distorted square planar, with a chelating closo-carborane ligand
coordinated to the nickel atom and two chloride atoms at the cis-
ꢀ
position. NieCl distances (2.1827(10) and 2.1846(9) A) are smaller
ꢀ
than the previous reported NieBr (ca. 2.31 A) [36] and PdeCl (ca.
ꢀ
2.34 A) [37] bond lengths, and are equal within experimental errors
with that of the published diphosphine nickel dichloride complexes
ꢀ
(usually 2.20 A) [39e41]. NieP distances (2.1535(10) and 2.1561
ꢀ
(9) A) are consistent with the previous reported NieP bond lengths
[35,36]. The bond length of C1eC2 in the closo-carborane is 1.678
ꢀ
(4) A, slightly smaller than that of the free ligand due to coordination
and obviously longer than that of the nido-carborane [14,42].
The angles (Cl(1)eNi(1)eCl(2) 93.32(4)ꢁ, Cl(1)eNi(1)eP(2) 88.72
(4)ꢁ, P(1)eNi(1)eP(2) 91.42(4)ꢁ, P(1)eNi(1)eCl(2) 86.48(4)ꢁ) are
approximate to the right angles, which also indicates the coordina-
tion sphere of the Ni atom is a approximate squareplanar. The atoms,
Ni(1), Cl(1), Cl(2), P(2) and P(1), are almost in one plane, with the
ꢀ
average deviations 0.067 A. The dihedral angle between the plane Ni
(1)Cl(1)Cl(2)P(2)P(1) and P(2)C(2)C(1)P(1) is about 22.0ꢁ, which is
apparently bigger than that of NiBr2[(PPh2)2(C2B10H10)] (ca. 9.5ꢁ)
[36] and similar to that of PdCl2[(PPh2)2(C2B10H10)] (ca. 23.3ꢁ) [37].
PdCl2[(PPh2)2(C2B10H10)] was synthesized according to the
previous report [37]. With these dichloride complexes MCl2[(PPh2)2-
Ph2
P
Cl
Cl
PPh2
PPh2
NiCl2(DME)
CH2Cl2
C
C
Ni
C
C
P
Ph2
Fig. 1. Molecular structure of complex 2 (hydrogen atoms are omitted for clarity,
ellipsoids set at the 30% probability level). Selected bond lengths [Å] and angles [ꢁ]: Ni
(1)eCl(1) 2.1827(10), Ni(1)eCl(2) 2.1846(9), Ni(1)eP(1) 2.1535(10), Ni(1)eP(2) 2.1561
(9), C(1)eC(2) 1.678(4), C(1)eP(2) 1.880(3), C(2)eP(1) 1.881(3); Cl(1)eNi(1)eCl(2)
1
2
93.32(4), Cl(1)eNi(1)eP(2) 88.72(4)
, P(1)eNi(1)eP(2) 91.42(4), P(1)eNi(1)eCl(2)
Scheme 2. Synthesis of complex 2.
86.48(4), Cl(1)eNi(1)eP(1) 179.51(3), Cl(2)eNi(1)eP(2) 172.05(3)).

506
X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
O
CF3
O
S
S
Ph2
P
H
Ph2
P
O
O
C
C
Pd
Pd
C
C
M = Pd
P
P
Ph2
O
H
Ph2
CH2Cl2
Ph2
P
Cl
Cl
AgOTf
4
O
CF3
C
M
C
P
Ph2
Ph2
P
H
Ph2
P
Ph2
Ph2
P
Cl
Cl
Cl
P
C
C
C
C
C
M = Ni (2), Pd (3)
Ag
Ni
M = Ni
Ag
C
Ag
C
C
+
P
P
P
P
Ph2
Cl
Ph2
Ph2
Ph2
CH2Cl2
5
6
Scheme 3. Reactivity differences between 2 and 3 with AgOTf.
Stirring the mixture of NiCl2[(PPh2)2(C2B10H10)] and AgOTf
ꢀ20 to 0 ppm. This can be unambiguously attributed to the opening
of the carborane ligand. The signals at 2568 cmꢀ1(4), 2576 cmꢀ1(5),
2560 cmꢀ1 (6) in IR spectra are characteristic of BeH vibrations.
The molecular structure of complex 4 is depicted in Fig. 2.
The structure of complex 4 shows two distorted square planar
palladium centers. The palladiumephosphorus bond distances of
in CH2Cl2 solution for 2 h did not afford the analog of complex 4, but
led to the formation of complex 5 as a major product and complex
6 as a by-product (Scheme 3). This results differ from that of
PdCl2[(PPh2)2(C2B10H10)]. The results are also different from Evans’
report [44], in which [Ni((S)-Tol-BINAP)]Cl2 (type d in Scheme 1) was
used to react with AgOTf to afford [Ni((S)-Tol-BINAP)](OTf)2. Complex
5 was a heteronuclear product containing both nickel and silver
atoms. It is surprising that in complex 5 the nickel side’s carborane
cage is opened and the silver side’s carborane remains closed. It is
supposed that due to the strong bonding of silver to chloride, no or
negligible electron density is transferred from the silver metal to the
carborane cage. So B(3)/B(6) of the closo-carborane was not attacked
and the closo nature of the cage is maintained. Complex 6 was
homonuclear by-product with the silver centers bridging with two
chlorides. The isomer of complex 6 was also made previously by
refluxing AgCl and [(PPh2)2(C2B10H10)] in ethanol solution [45].
Complexes 4e6 were characterized by 1H NMR,11B NMR and FT-IR
spectroscopy. The 1H NMR spectra of complexes 4e6 show resonance
ꢀ
2.222e2.226 A are in the normal range for cis-chelated phosphorus.
ꢀ
The PdeO distances are 2.163(4), 2.165(4) A in complex 4. These
values compare favourably with the corresponding bond distances
in the reported PdeO complexes [46e49]. The bond length of
ꢀ
C1eC2 in the nido-carborane is 1.580(7) A, smaller than that of the
closo-carborane due to the opening of carborane cage. The
ꢀ
distances of SeO are 1.422(4),1.451(4), 1.453(4) A, respectively. This
is different from the free triflate anion, which indicates O(1)eS(1)e
2
O(2) a conjugated 3p system. The bond angles around the palla-
dium atoms are close to the expected values of 90ꢁ. The PePdeP
chelating angle is 84.61(6)ꢁ in complex 4, which is similar to the
at d 7.36e8.06 ppm, which are typical for the phenyl group. A broad
single resonance at ꢀ2.23 ppm in 1H NMR spectra of complex 4
indicates the bridge H atom of BeHeB in the nido-carborane
[19e24,35,36] The 11B NMR spectra of 4 and 5 exhibit signals beyond
Fig. 3. Molecular structure of complex 5 (hydrogen atoms are omitted for clarity,
ellipsoids set at the 30% probability level; bonds in pꢁhenyl group are drawn as thin
ꢀ
lines for clarity). Selected bond lengths [A] and angles [ ]: Ag(1)eNi(1) 3.183(4), Ni(1)e
Cl(1) 2.222(5), Ni(1)eCl(2) 2.214(4), Ni(1)eP(3) 2.179(4), Ni(1)eP(4) 2.188(4), C(3)eC
(4) 1.555(15), C(3)eP(3) 1.813(10), C(4)eP(4) 1.843(11), Ag(1)eCl(1) 2.624(5), Ag(1)eCl
(2) 2.520(4), Ag(1)eP(1) 2.488(5), Ag(1)eP(2) 2.470(5), C(1)eC(2) 1.751(14), C(1)eP(1)
1.885(10), C(2)eP(2) 1.879(11); Cl(1)eNi(1)eCl(2) 91.92(18), Cl(1)eNi(1)eP(4) 171.12
(13), P(3)eNi(1)eP(4) 84.83(17), P(3)eNi(1)eCl(1) 90.75(18), Cl(2)eNi(1)eP(3) 177.26
(13), Cl(2)eNi(1)eP(4) 92.61(17), Cl(1)eAg(1)eCl(2) 76.58(16), Cl(1)eAg(1)eP(1)
114.27(15) , P(2)eAg(1)eP(1) 87.00(13), P(2)eAg(1)eCl(1) 127.48(10), Cl(2)eAg(1)eP
(2) 126.70(13), Cl(2)eAg(1)eP(1) 129.77(14), Ag(1)eCl(1)eNi(1) 81.67(13), Ag(1)eCl
(2)eNi(1) 84.24(15).
Fig. 2. Molecular structure of complex 4 (hydrogen atoms are omitted for clarity,
ꢁ
ꢀ
ellipsoids set at the 30% probability level). Selected bond lengths [A] and angles [ ]: Pd
(1)eO(1) 2.163(4), Pd(1)eO(2) 2.165(4), Pd(1)eP(1) 2.2216(18), Pd(1)eP(2) 2.2262(17),
C(1)eC(2) 1.580(7), C(1)eP(1) 1.812(6), C(2)eP(2) 1.806(5), S(1)eO(1) 1.422(4), S(1)eO
(2) 1.451(4), S(1)eO(3) 1.453(4); O(1)ePd(1)eO(2) 87.20(14), O(1)ePd(1)eP(2) 93.80
(11) , P(1)ePd(1)eP(2) 84.61(6), P(1)ePd(1)eO(2) 95.53(10), O(1)ePd(1)eP(1) 170.91
(12), O(2)ePd(1)eP(2) 172.56(12).

X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
507
center geometry is distorted tetrahedral. The dihedral angle
between the plane Ag(1)Cl(1)Cl(2) and plane Ni(1)Cl(1)Cl(2) is 53.7ꢁ.
The perspective drawing of complex 6 is given in Fig. 4. The
molecular structure shows that complex 6 was a homonuclear
product containing two silver centers, which is structurally different
from the reported [Ag2(m-Cl)2{(PPh2)2(C2B10H10)}2] [45]. The
geometries at the silver centers are somewhat distorted tetrahedral.
ꢀ
The distance between Ag1 and Ag2 is about 3.32 A, shorter than the
ꢀ
reported 3.594 A. The distance is also shorter than twice of the Van
ꢀ
der Waals radius of Ag (3.40 A), which indicates a weak interaction
between the two silver atoms. The bond lengths of CeC in the closo-
ꢀ
ꢀ
carborane are 1.768(13) A and 1.785(12) A, showing no marked
difference with that of other closo-carborane derivatives. The
ꢀ
ꢀ
distances between Ag and Cl are ranging from 2.502 A to 2.620 A,
which are essentially equal with the published results. The ligand
“bite” angles are 86.1ꢁ (P(1)eAg(1)eP(2)) and 84.4ꢁ (P(3)eAg(2)eP
(4)), similar to those obtained for the chelated silver carborane
complexes. The angles of Ag(1)eCl(1)eAg(2) and Ag(1)eCl(2)eAg
(2) are 80.80(9) and 79.95(8)ꢁ, respectively, which is similar with
that of complex 5 (81.67ꢁ, 84.24ꢁ). The dihedral angle between the
plane Ag(1)Cl(1)Cl(2) and plane Ag(2)Cl(1)Cl(2) is 30.3ꢁ. While in
the published report [45], the two silver atoms and two chloride
atoms are in one plane. This can be attributed to the AgeAg contact
in complex 6, which made the plane distorted. The plane Ag(1)P(1)P
(2) and plane Ag(1)Cl(1)Cl(2), plane Ag(2)P(3)P(4) and plane Ag(2)Cl
(1)Cl(2) are almost perpendicular, with the dihedral angles 87.45ꢁ
and 87.15ꢁ. This is identical to the published report (87.56ꢁ).
The CH2Cl2 solution of [(PPh2)2(C2B10H10)] and AgOTf was stirred
for 2 h. The color of the solution changes from colorless to yellow
slowly. After isolation, complex 7 was obtained in 93% yields.
Complex 7 contains two closo-carborane ligands and two Ag centers,
which was bridged by two triflate anions (Scheme 4).
Fig. 4. Molecular structure of complex 6 (hydrogen atoms are omitted for clarity,
ellipsoids set at the 30% probability level; bonds in phenyl group are drawn as thin
ꢁ
ꢀ
lines for clarity). Selected bond lengths [A] and angles [ ]: Ag(1)eAg(2) 3.3197(16),
Ag(1)eCl(1) 2.618(3), Ag(1)eCl(2) 2.546(3), Ag(1)eP(1) 2.495(3), Ag(1)eP(2) 2.486(3),
C(1)eC(2) 1.768(13), C(1)eP(1) 1.879(9), C(2)eP(2) 1.868(10), Ag(2)eCl(1) 2.502(3), Ag
(2)eCl(2) 2.620(3), Ag(2)eP(3) 2.535(3), Ag(2)eP(4) 2.468(3), C(3)eC(4) 1.785(12),
C(3)eP(3) 1.852(9), C(4)eP(4) 1.870(10); Cl(1)eAg(2)eCl(2) 96.59(9), Cl(1)eAg(2)eP
(4) 129.11(10), P(3)eAg(2)eP(4) 84.35(9), P(3)eAg(2)eCl(1) 113.88(11), Cl(2)eAg(2)eP
(3) 113.49(10), Cl(2)eAg(2)eP(4) 119.95(9), Cl(1)eAg(1)eCl(2) 95.58(10), Cl(1)eAg(1)e
P(1) 111.58(10), P(2)eAg(1)eP(1) 86.14(9), P(2)eAg(1)eCl(1) 117.15(11), Cl(2)eAg(1)eP
(2) 131.19(11), Cl(2)eAg(1)eP(1) 115.71(10), Ag(1)eCl(1)eAg(2) 80.80(9), Ag(1)eCl
(2)eAg(2) 79.95(8).
corresponding bond angles in the related Pd complex [Pd
(OAc)2(dppe)] (type b in Scheme 1) [46] but smaller than the
PePdeP angle in Hor’s report (type c in Scheme 1) [47]. The
dihedral angle between the plane Pd(1)O(1)O(2A)P(2)P(1) and P(2)
C(2)C(1)P(1) is about 23.1ꢁ, which is similar to that of
PdCl2[(PPh2)2(C2B10H10)] (ca. 23.3ꢁ) [37].
The formation of 7 is confirmed by the appearance of signals at
7.49, 7.55 and 8.01 ppm in the 1H NMR spectrum, which can be
ascribed to the phenyl group. The 11B NMR spectrum exhibits reso-
nances at ꢀ6.2, ꢀ7.8, ꢀ12.2, ꢀ13.2 ppm, which indicated that closo-
carborane remains. The IR spectrum shows a strong broad signal for
The ORTEP drawing of complex 5 is shown in Fig. 3. The molec-
ular structure shows that complex 5 was a heteronuclear product
containing a nickel center and silver center. The nickel center is in
a distorted square environment, with nickel atom deviating only
the BeH vibration at approximately 2578 cmꢀ1
.
The molecular structure of complex 7 is shown in Fig. 5. The
molecular structure shows that the geometries at the silver centers
are distorted tetrahedral. The silverephosphorus distances of
ꢀ
0.07 A from the coordinating plane (P3eP4eCl1eCl2). The silver
ꢀ
center is coordination by two Cl groups and a chelated diphosphino-
2.462e2.482 A are in the normal range for bond length of AgeP. The
ꢀ
closo-carborane ligand, possessing a distorted tetrahedral geometry.
bond lengths of CeC in the closo-carborane are 1.744(17) A and 1.800
ꢀ
ꢀ
Interestingly, the distance between Ag1 and Ni1 is 3.183(4) A, a little
(18) A. These values compare favorably with the corresponding
ꢀ
shorter than sum of the Van der Waals radius of Ag and Ni (3.35 A),
bond distances in the closo-carborane complexes. The plane Ag(1)O
(1)O(4) and plane Ag(2)O(2)O(5) are almost parallel with each other,
with the dihedral angle only 0.194ꢁ. The plane Ag(1)P(1)P(2) and
plane Ag(1)O(1)O(4), plane Ag(2)P(3)P(4) and plane Ag(2)O(2)O(5)
are almost perpendicular, with the dihedral angles 81.6ꢁ and 88.1ꢁ.
Complex 7 was also used to react with MCl2[(PPh2)2(C2B10H10)]
(M ¼ Ni, Pd). Treatment of 2 and 7 affords only 5 in 90% yields. And
complex 6 was not found in this reaction. It is surprising that reaction
which indicates a weak interaction between them. The distance
ꢀ
between C1 and C2 is 1.751(14) A, while the bond length of C3eC4 is
ꢀ
1.555(15) A. These values are comparable with that of the closo- and
nido-carborane. The dihedral angle between plane Ag(1)Cl(1)Cl(2)
and plane Ag(1)P(1)P(2) is 81.50ꢁ, while the dihedral angle between
plane Ni(1)Cl(1)Cl(2) and plane Ni(1)P(1)P(2) is only 7.76ꢁ. This also
confirms that the nickel center is distorted square and the silver
O
CF3
O
S
S
Ph2
P
Ph2
P
O
O
PPh2
C
AgOTf
C
C
Ag
C
Ag
C
C
P
P
PPh2
CH2Cl2
Ph2
Ph2
O
1
O
CF3
7
Scheme 4. Synthesis of complex 7.

508
X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
Fig. 5. Molecular structure of complex 7 (hydrogen atoms are omitted for clarity,
ellipsoids set at the 30% probability level; bonds in phenyl group are drawn as thin lines
ꢁ
ꢀ
Fig. 6. Molecular structure of complex 8 (hydrogen atoms are omitted for clarity,
for clarity). Selected bond lengths [A] and angles [ ]: Ag(1)eO(4) 2.244(12), Ag(1)eO(1)
2.380(10), Ag(1)eP(1) 2.462(5), Ag(1)eP(2) 2.482(5), P(1)eC(1) 1.868(12), P(2)eC(2)
1.894(12), C(1)eC(2) 1.744(17), Ag(2)eO(5) 2.341(10), Ag(2)eO(2) 2.349(12), Ag(2)eP
(3) 2.466(6), Ag(2)eP(4) 2.472(5), P(3)eC(3) 1.869(13), P(4)eC(4) 1.864(13), C(3)eC(4)
1.800(18); O(4)eAg(1)eO(1) 94.2(5), O(4)eAg(1)eP(1) 126.5(4), O(1)eAg(1)eP(1)
111.3(3), O(4)eAg(1)eP(2) 116.9(5), O(1)eAg(1)eP(2) 121.5(3), P(1)eAg(1)eP(2) 89.2
(2), O(5)eAg(2)eO(2) 95.8(4), O(5)eAg(2)eP(3) 126.7(3), O(2)eAg(2)eP(3) 111.8(3),
O(5)eAg(2)eP(4) 120.2(3), O(2)eAg(2)eP(4) 111.5(4), P(3)eAg(2)eP(4) 91.5(2).
ꢁ
ꢀ
ellipsoids set at the 30% probability level). Selected bond lengths [A] and angles [ ]: Pd
(1)eP(2) 2.227(2), Pd(1)eP(1) 2.231(2), Pd(1)eCl(1) 2.399(2), Pd(1)eCl(1A) 2.391(2),
P(1)eC(1) 1.808(4), P(2)eC(2) 1.800(5), C(1)eC(2) 1.570(6); P(2)ePd(1)eP(1) 85.27(5),
P(2)ePd(1)eCl(1A) 94.21(5), P(1)ePd(1)eCl(1A) 177.29(6), P(2)ePd(1)eCl(1) 177.65
(6), P(1)ePd(1)eCl(1) 95.26(5), Cl(1A)ePd(1)eCl(1) 85.16(5).
of dichloromethane and acetonitrile. Complexes 8e9 have no
significant difference with the previous report [50] in bond lengths,
angles and dihedral angles, except that the unit cell of complex 9
contains one and a half CH3CN solvent (Figs. 6 and 7).
of 3 and 7 did not afford 4, or analog of complex 5. After chromato-
graphic separation on silica gel, complex 8, 9 and 6 are obtained.
Complex 8 contains two Pd centers, bridged by two chlorides.
Complex 9 has only one Pd center, whose charge was balanced by
two carborane anions. It should be noted that 8 and 9 have also been
reported using 1 and PdCl2 in different solvents [50] (Scheme 5).
The IR, 1H NMR and 11B NMR spectra of complexes 4 and 6 are
same as the ones described above. The IR, 1H NMR and 11B NMR
spectra of complexes 8 and 9 show no significant differences with
the above results. For example, signals of phenyl group are located
at ca. 7.49e8.01 ppm. The BeHeB signals of 8 and 9 are ꢀ2.23
and ꢀ2.06 ppm, respectively. In 11B NMR spectra, all samples
show characteristic signal for nido-carborane. Resonances of
2556 cmꢀ1and 2577 cmꢀ1 in IR spectra indicate the intense BeH
stretching of carborane in 8 and 9.
3. Conclusions
The reactivity differences of MCl2[(PPh2)2(C2B10H10)] (M ¼ Ni
(2), Pd (3)) with AgOTf and [Ag2(m-OTf)2{(PPh2)2(C2B10H10)}2] (7)
was studied. PdCl2[(PPh2)2(C2B10H10)] react with AgOTf can afford
4, while the reaction of NiCl2[(PPh2)2(C2B10H10)] and AgOTf led to
the formation of 5 and 6. The reaction of NiCl2[(PPh2)2(C2B10H10)]
and 7 only produce complex 5, however, 8, 9, and 6 were obtained
from the reaction of PdCl2[(PPh2)2(C2B10H10)] and 7. It is apparently
shown that only complex 4 can be used to synthesize molecular
squares. The studies of MCl2[(PPh2)2(C2B10H10)] (M ¼ Ni, Pd) with
different silver salts and using complex 4 as starting materials to
construct molecular squares are currently in progress in our group.
Single crystals suitable for X-ray crystallography of 8 and 9 were
obtained by slow evaporation of diethyl ether to a mixture solution
Ph2
H
Ph2
P
Cl
Cl
P
C
C
Ag
Ni
C
M = Ni
C
P
P
Ph2
Ph2
CH2Cl2
Ph2
P
5
Cl
Cl
7
C
M
C
P
Ph2
Ph2
H
H
Ph2
P
Ph2
Ph2
P
H
P
Cl
Cl
P
2
3
C
M = Ni ( ), Pd ( )
C
C
C
M = Pd
Pd
Pd
Pd
C
C
C
C
P
P
P
CH2Cl2
+
P
Ph2
Ph2
H
Ph2
Ph2
8
9
Ph2
P
Ph2
P
Cl
C
C
Ag
Ag
6
C
C
+
P
P
Ph2
Ph2
Cl
Scheme 5. Reactivity differences between 2 and 3 with 7.

X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
509
The reagents and solvents were used without further purification. 1H
NMR(500 MHz) and 11B NMR(160 MHz) spectra were recorded on
a Bruker DMX 500 Spectrometer at room temperature in CDCl3
solutions, using TMS (1H NMR), BF3$OEt2 (11B NMR) as an internal or
external standard. IR spectra were recorded on the Nicolet AVATAR-
360 IR spectrometer. Elemental analyses for C, H were carried out on
an Elementar III Vario EI Analyzer.
4.2. Syntheses and characterization
4.2.1. Synthesis of NiCl2[(PPh2)2(C2B10H10)] (2)
NiCl2(DME) (53 mg, 0.24 mmol) was added to a 10 mL CH2Cl2
solution of [(PPh2)2(C2B10H10)] (103 mg, 0.20 mmol)and stirred for
10 h at room temperature. The reaction mixture was filtered
through Celite. The filtrate was dried under vacuum. The obtained
orange solid was washed with diethyl ether and dried in vacuo.
Yield: 117 mg (91%). 1H NMR (500 MHz, CDCl3):
d 8.48 (d, 8H, Hph),
7.64 (d, 4H, Hph), 7.58 (t, 8H, Hph) ppm. 11B NMR (160 MHz, CDCl3):
d
ꢀ4.7, ꢀ5.6, ꢀ7.0, ꢀ7.9, ꢀ11.1, ꢀ12.0 ppm. IR (KBr disk): 2558 cmꢀ1
(vBeH). Anal. Calcd. for C26H30B10P2Cl2Ni (642.17): C, 48.63; H, 4.71.
Found: C, 48.10; H, 4.69%.
Fig. 7. Molecular structure of complex 9 (hydrogen atoms are omitted for clarity,
ꢁ
ꢀ
ellipsoids set at the 30% probability level). Selected bond lengths [A] and angles [ ]: Pd
(1)eP(2) 2.3444(8), Pd(1)eP(1) 2.3460(9), Pd(1)eP(4) 2.3513(9), Pd(1)eP(3) 2.3652(9),
P(1)eC(1) 1.816(3), P(2)eC(2) 1.825(3), P(3)eC(3) 1.828(3), P(4)eC(4) 1.808(3), C(1)eC
(2) 1.571(4), C(3)eC(4) 1.574(5); P(2)ePd(1)eP(1) 83.48(3), P(2)ePd(1)eP(4) 99.08(3),
P(1)ePd(1)eP(4) 156.08(3), P(2)ePd(1)eP(3) 163.22(3), P(1)ePd(1)eP(3) 100.88(3),
P(4)ePd(1)eP(3) 83.54(3).
4.2.2. Synthesis of [Pd2(m-OTf)2{(PPh2)2(C2B9H10)}2] (4)
A mixture of PdCl2[(PPh2)2(C2B10H10)] (138 mg, 0.2 mmol) and
AgOTf (103 mg, 0.4 mmol) in CH2Cl2 was stirred for 2 h at room
temperature. The solution was filtered through Celite to remove the
silver salt. After evaporating the filtrate under vacuum, the residue
was washed with diethyl ether and dried in vacuo. Red single
crystals suitable for X-ray diffraction analysis were obtained by slow
diffusion of hexane into a CH2Cl2 solution of 4 at room temperature.
4. Experimental section
4.1. General procedures
Yield: 144 mg (95%). 1H NMR (500 MHz, CDCl3):
d 8.06 (d, 16H, Hph),
7.54 (d, 8H, Hph), 7.47 (t,16H, Hph), ꢀ2.23 (br s, 2H, BeHeB) ppm. 11
B
Manipulation of air-sensitive complexes was performed under
NMR (160 MHz, CDCl3):
d
5.8, ꢀ8.9, ꢀ13.8, ꢀ17.2, ꢀ19.5, ꢀ23.2,
a
controlled dry argon atmosphere using standard Schlenk
ꢀ32.5, ꢀ36.6, ꢀ37.3 ppm. IR (KBr disk): 2568 cmꢀ1 (vBeH). Anal.
Calcd. for C54H60O6B18F6S2P4Pd2 (1514.49): C, 42.83; H, 3.99. Found:
C, 42.96; H, 3.95%.
techniques or inert-gas gloveboxes. NiCl2(DME) [51] and [(PPh2)2-
(C2B10H10)] [52] were prepared according to the literature procedure.
Table 1
Details of the crystal parameters, data collections and refinements for 2, 4e6.
2
4$2CH2Cl2
5$H2O
6
Empirical formula
Formula weight
Crystal system
Space group
C
26H30B10Cl2NiP2
C56H64B18Cl4F6O6P4Pd2S2
1684.25
Triclinic
C52H62AgB19Cl2NiOP4
1269.77
Triclinic
C52H60Ag2B20Cl2P4
1311.72
Monoclinic
P2(1)/n
10.139(5)
32.002(15)
20.109(9)
90
91.162
90
6524(5)
4
642.15
Triclinic
P
ꢀ1
P
ꢀ1
P
ꢀ1
ꢀ
a (A)
8.347(3)
11.550(5)
12.242(5)
15.896(7)
69.359(6)
77.982(7)
62.780(5)
1867.3(14)
1
11.434(19)
16.83(3)
19.30(3)
109.44
96.12(3)
105.27(3)
3300(10)
2
1.278
0.795
ꢀ
b (A)
11.001(4)
17.225(6)
89.309(5)
84.707(5)
75.823(4)
1526.8(10)
2
ꢀ
c (A)
a
b
g
(deg)
(deg)
(deg)
3
ꢀ
Volume (A )
Z
Dcalcd (Mg / m3)
1.397
0.934
1.498
0.827
1.336
0.814
m
(mmꢀ1
)
F(000)
q
656
2.24e26.01
6873
5802
0.0307
26.01 (96.3%)
0.9124, 0.8352
5802/0/380
0.923
R1 ¼ 0.0400, wR2 ¼ 0.0982
R1 ¼ 0.0560, wR2 ¼ 0.1037
0.381, ꢀ0.536
844
1.37e25.01
7797
6470
0.0458
25.01 (98.1%)
0.9219, 0.8860
6470/0/464
0.823
R1 ¼ 0.0510, wR2 ¼ 0.0920
R1 ¼ 0.1003, wR2 ¼ 0.1036
0.695, ꢀ0.538
1292
1.35e25.01
13,838
11,382
0.1324
25.01 (97.9%)
0.9247, 0.8900
11382/0/744
0.915
R1 ¼ 0.1120, wR2 ¼ 0.2592
R1 ¼ 0.1997, wR2 ¼ 0.2923
1.696, ꢀ1.172
2640
1.20e25.01
26,836
11,454
0.1092
25.01 (99.7%)
0.9086, 0.8541
11454/0/742
0.927
R1 ¼ 0.0860, wR2 ¼ 0.2123
R1 ¼ 0.1671, wR2 ¼ 0.2375
0.644, ꢀ0.818
range (ꢁ)
Reflections collected
Independent reflections
Rint
Completeness to
q
(ꢁ)
Max., min. transmission
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [I > 2
R indices (all data)
s
(I)]a
3
ꢀ
Drmax, min (e/A )
P
P
a
R1
¼
kFoj ꢀ jFck/ jFoj; wR2 ¼ [Sw(F2o ꢀ F2c)2/Sw(Fo2)2]1/2
.

510
X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
Table 2
Details of the crystal parameters, data collections and refinements for 7e9.
7$CH2Cl2
8
9$1.5CH3CN
Empirical formula
Formula weight
Crystal system
Space group
C
55H62Ag2B20Cl2F6O6P4S2
C52H60B18Cl2P4Pd2
1287.16
Monoclinic
C2/c
28.216(19)
16.668(11)
21.411(14)
90
128.212
90
7912(9)
4
C55H64.50B18N1.50P4Pd
1171.44
Monoclinic
P2(1)/c
26.275(4)
16.758(2)
27.321(4)
90
98.067(2)
90
1623.89
Monoclinic
P2(1)/c
20.78(5)
19.58(5)
18.63(5)
90
105.75(4)
90
7297(32)
4
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
a
b
g
(deg)
(deg)
(deg)
3
ꢀ
Volume (A )
Z
11,911(3)
8
1.307
Dcalcd (Mg/m3)
1.478
0.816
1.081
0.630
m
(mmꢀ1
)
0.458
F(000)
q
3256
1.46e25.01
27,945
12,807
0.1798
25.01 (99.6%)
0.9228, 0.8409
12,807/2/883
0.899
R1 ¼ 0.1021, wR2 ¼ 0.2427
R1 ¼ 0.2196, wR2 ¼ 0.3234
2.018, ꢀ1.285
2592
1.53e25.01
16,232
6951
0.0652
25.01 (99.4%)
0.9396, 0.9114
6951/0/374
0.762
R1 ¼ 0.0446, wR2 ¼ 0.1028
R1 ¼ 0.0862, wR2 ¼ 0.1092
0.555, ꢀ1.032
4808
1.43e27.01
55,925
25,309
0.0549
27.01 (97.3%)
0.9556, 0.9139
25,309/0/1523
1.024
R1 ¼ 0.0438, wR2 ¼ 0.0969
R1 ¼ 0.0828, wR2 ¼ 0.1156
1.033, ꢀ0.612
range (ꢁ)
Reflections collected
Independent reflections
Rint
Completeness to
q
(ꢁ)
Max., min. transmission
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2
R indices (all data)
s
(I)]a
3
ꢀ
Drmax, min (e/A )
P
P
a
R1
¼
kFoj ꢀ jFck/ jFoj; wR2 ¼ [Sw(F2o ꢀ F2c)2/Sw(Fo2)2]1/2
.
4.2.3. Synthesis of [Ni{(PPh2)2(C2B9H10)}](
m-Cl)2[Ag
2578 cmꢀ1 (vBeH). Anal. Calcd. for C54H60O6B20F6P4S2Ag2 (1539.01):
{(PPh2)2(C2B10H10)}] (5) and [Ag2( -Cl)2{(PPh2)2(C2B10H10)}2] (6)
m
C, 42.14; H, 3.93. Found: C, 41.98; H, 3.90%.
A mixture of NiCl2[(PPh2)2(C2B10H10)] (128 mg, 0.2 mmol) and
AgOTf (103 mg, 0.4 mmol) in CH2Cl2 was stirred for 2 h at room
temperature. The solution was filtered through Celite to remove the
silver salt. After evaporating the filtrate under reduced pressure,
the residue was chromatographed on silica gel. Elution with
CH2Cl2ehexane (3:1) and CH2Cl2eacetone (4:1) affords complex 6
and complex 5 as a white and orange power. Red (5) and colorless
(6) single crystals suitable for X-ray diffraction analyses were
grown by slow evaporation of diethyl ether into dichloromethane
solution of 5 and 6 at room temperature, respectively. 5: Yield:
4.2.5. Synthesis of [Pd2(
{(PPh2)2(C2B9H10)}2] (9) and [Ag2(
m
-Cl)2{(PPh2)2(C2B9H10)}2] (8), [Pd
-Cl)2{(PPh2)2(C2B10H10)}2] (6)
m
A mixture of PdCl2[(PPh2)2(C2B10H10)] (138 mg, 0.2 mmol) and 7
(154 mg, 0.1 mmol) in CH2Cl2 was refluxed for 5 h. After evaporating
the filtrate under reduced pressure, the residue was chromatographed
on silica gel. Elution with CH2Cl2ehexane (3:1) and CH2Cl2eacetone
(4:1) affords colorless zone, yellow zone and orange zone containing
complex 6, complex 8 and complex 9, respectively. Yellow (8) and red
(9) single crystals suitable for X-ray diffraction analyses were grown by
slow evaporation of diethyl ether into CH2Cl2 and CH3CN solution
mixture of 8 and 9 at room temperature, respectively. 8: Yield: 73 mg
61 mg (49%). 1H NMR (500 MHz, CDCl3):
7.60e7.45 (m, 24H, Hph
ppm, BeHeB not found. 11B NMR
d 7.95 (d, 16H, Hph),
)
(160 MHz, CDCl3):
d
ꢀ2.9, ꢀ4.3, ꢀ6.8, ꢀ10.8, ꢀ12.9, ꢀ20.1,
(28%).1H NMR (500 MHz, CDCl3):
d8.19 (m,16H, Hph), 7.72 (m, 8H, Hph),
ꢀ34.6 ppm. IR (KBr disk): 2576 cmꢀ1 (vBeH). Anal. Calcd. for
7.65 (m, 16H, Hph), ꢀ2.23 (br s, 2H, BeHeB) ppm. 11B NMR (160 MHz,
C52H60B19P4Cl2NiAg (1251.80): C, 49.89; H, 4.83. Found: C, 49.35; H,
CDCl3):
d
8.5, ꢀ11.8, ꢀ15.7, ꢀ18.6, ꢀ20.2, ꢀ32.1, ꢀ39.6 ppm. IR (KBr
4.79%. 6: Yield: 24 mg (18%). 1H NMR (500 MHz, CDCl3):
d
7.90 (d,
disk): 2556 cmꢀ1 (vBeH). Anal. Calcd. for C52H60B18P4Cl2Pd2 (1287.27):
16H, Hph), 7.43 (d, 8H, Hph), 7.36 (t, 16H, Hph) ppm. 11B NMR
C, 48.52; H, 4.70. Found: C, 48.21; H, 4.73%. 9: Yield: 57 mg (26%). 1H
(160 MHz, CDCl3):
d
ꢀ2.3, ꢀ3.2, ꢀ6.4, ꢀ8.7, ꢀ9.8, ꢀ11.1, ꢀ13.4 ppm.
NMR (500 MHz, CDCl3): d 8.19 (d, 16H, Hph), 7.53 (d, 8H, Hph), 7.46 (t,
IR (KBr disk): 2560 cmꢀ1 (vBeH). Anal. Calcd. for C52H60B20P4Cl2Ag2
(1311.79): C, 47.61; H, 4.61. Found: C, 47.21; H, 4.57%.
16H, Hph), ꢀ2.06 (br s, 2H, BeHeB) ppm. 11B NMR (160 MHz, CDCl3):
d
7.8, ꢀ12.0, ꢀ18.2, ꢀ25.2, ꢀ33.5, ꢀ35.6, ꢀ36.3 ppm. IR (KBr disk):
Another method for 5: complex 2 (64 mg, 0.2 mmol) was added
to a 10 mL CH2Cl2 solution of Complex 7 (154 mg, 0.10 mmol) and
stirred for 4 h at room temperature. After evaporating the solvent
under vacuum, the solid was washed with diethyl ether and dried
in vacuo. Yield: 113 mg (90%).
2577 cmꢀ1 (vBeH). Anal. Calcd. forC52H60B18P4Pd (1109.94): C, 56.27; H,
5.45. Found: C, 55.96; H, 5.51%. 6: Yield: 35 mg (13%). Characterization
was in agreement with the above report.
4.3. X-ray crystallography
4.2.4. Synthesis of [Ag2(m-OTf)2{(PPh2)2(C2B10H10)}2] (7)
Diffraction data of 2, 4e9 were collected on a Bruker SMART
To a solution of (PPh2)2(C2B10H10) (103 mg, 0.20 mmol) in 10 mL
CH2Cl2 was added AgOTf (51 mg, 0.2 mmol), the mixture was stir-
red for 5 h at room temperature and the color gradually changed
from colorless to yellow. After evaporating the solvent under
vacuum, the obtained solid was washed with diethyl ether and
dried in vacuo. Yield: 146 mg (93%). 1H NMR (500 MHz, CDCl3):
APEX CCD diffractometer with graphite-monochromated MoKa
ꢀ
radiation (
temperature using the
l
¼ 0.71073 A). All the data were collected at room
u
scan technique. These structures were
solved by direct methods, using Fourier techniques, and refined on
F2 by using full-matrix least-squares techniques. All non-hydrogen
atoms were refined with anisotropic thermal parameters. All the
hydrogen atoms were included but not refined. All the calculations
were carried out with the SHELXTL program [53]. Crystal data, data
d
8.01 (d,16H, Hph), 7.55 (d, 8H, Hph), 7.49 (t,16H, Hph) ppm. 11B NMR
(160 MHz, CDCl3):
ꢀ6.2, ꢀ7.8, ꢀ12.2, ꢀ13.2 ppm. IR (KBr disk):
d

X.-Q. Xiao, G.-X. Jin / Journal of Organometallic Chemistry 696 (2011) 504e511
511
[19] F. Teixidor, G. Barbera, R. Kivekäs, R. Sillanpää, C. Viñas, Dalton Trans. (2007)
1668e1670.
[20] O. Tutusaus, R. Nunez, C. Viñas, F. Teixidor, I. Mata, E. Molins, Inorg. Chem. 43
(2004) 6067e6074.
collection parameters and the results of the analyses of complexes
2, 4e9 are summarized in Tables 1 and 2. In complex 5, the
hydrogen atoms of water were not found.
[21] C. Viñas, R. Núñez, I. Rojo, F. Teixidor, R. Kivekäs, R. Sillanpää, Inorg. Chem. 40
(2001) 3259e3260.
[22] F. Teixidor, R. Benakki, C. Viñas, R. Kivekäs, R. Sillanpää, Organometallics 17
(1998) 4630e4633.
Acknowledgments
[23] C. Viñas, M.R. Cirera, F. Teixidor, R. Kivekäs, R. Sillanpää, J. Llibre, Inorg. Chem.
37 (1998) 6746e6750.
[24] J.M. Dou, D.P. Zhang, Y.H. Zhu, D.C. Li, D.Q. Wang, Polyhedron 26 (2007)
4216e4222.
[25] D.S. Hampton, J. Am. Chem. Soc. 87 (1965) 1817e1818.
[26] M. Yoshizawa, J.K. Klosterman, M. Fujita, Angew. Chem. Int. Ed. 48 (2009)
3418e3438.
This work was supported by the National Science Foundation of
China (20531020, 20721063, and 20771028), Shanghai Science and
Technology Committee (08DZ2270500, 08DJ1400103), and
Shanghai Leading Academic Discipline Project (B108).
[27] S.S. Li, B.H. Northrop, Q.H. Yuan, L.J. Wan, P.J. Stang, Acc. Chem. Res. 42 (2009)
249e259.
Appendix A. Supplementary data
[28] J.K. Klosterman, Y. Yamauchi, M. Fujita, Chem. Soc. Rev. 38 (2009) 1714e1725.
[29] F.A. Cotton, C. Lin, C.A. Murillo, Acc. Chem. Res. 34 (2001) 759e771.
[30] S.S. Sun, A.J. Lees, Coord. Chem. Rev. 230 (2002) 170e192.
[31] F. Würthner, C.C. You, C.R. Saha-Möller, Chem. Soc. Rev. 33 (2004) 133e146.
[32] I. Rojo, F. Teixidor, C. Viñas, R. Kivekäs, R. Sillanpää, Chem. Eur. J. 10 (2004)
5376e5385.
[33] M. Fujita, J. Yazaki, K. Ogura, J. Am. Chem. Soc. 112 (1990) 5645e5647.
[34] P.J. Stang, D.H. Cao, J. Am. Chem. Soc. 116 (1994) 4981e4982.
[35] D.P. Zhang, J.M. Dou, D.C. Li, D.Q. Wang, Inorg. Chim. Acta 359 (2006)
4243e4249.
CCDC reference numbers 761994 (2), 761995 (4), 761996 (5),
761997 (6), 761998 (7), 761999 (8) and 762000 (9); contain the
supplementary crystallographic data for this paper. These data can
be obtained free of charge from the Cambridge Crystallographic
Data Center via www.ccdc.cam.ac.uk/data_request/cif.
References
[36] J.M. Dou, D.P. Zhang, D.C. Li, D.Q. Wang, J. Org. Chem. 691 (2006)
5673e5679.
[37] S. Paavola, R. Kivekäs, F. Teixidor, C. Viñas, J. Org. Chem. 606 (2000) 183e187.
[38] C. Viñas, M.M. Abad, F. Teixidor, R. Sillanpää, R. Kivekäs, J. Org. Chem. 555
(1998) 17e23.
[39] F. Cecconi, S. Midollini, A. Orlandini, L. Sacconi, Inorg Chim Acta 42 (1980)
59e63.
[40] U. Casellato, D. Ajo, G. Valle, B. Corain, B. Longato, R. Graziani, J. Crystallogr.
Spectrosc. Res. 18 (1988) 583e590.
[1] J.C. Clark, F.R. Fronczek, M.G.H. Vicente, Tetrahedron Lett. 46 (2005)
2365e2368.
[2] M.F. Hawthorne, Angew. Chem. Int. Ed. 32 (1993) 950e984.
[3] J.A. Weinstein, M.T. Tierney, E.S. Davies, K. Base, A.A. Robeiro, M.W. Grinstaff,
Inorg. Chem. 45 (2006) 4544e4555.
[4] K. Base, M.W. Grinstaff, Inorg. Chem. 37 (1998) 1432e1433.
[5] D.A. Brown, H.M. Colquhoun, J.A. Daniels, J.A.H. MacBride, I.R. MacBride,
R. Stephenson, K. Wade, J. Mater. Chem. 2 (1992) 793e796.
[6] C.H. Wu, D.H. Wu, X. Liu, G. Guoyiqibayi, D.D. Guo, G. Lv, X.M. Wang, H. Yan,
H. Jiang, Z.H. Lu, Inorg. Chem. 48 (2009) 2352e2354.
[41] S.C. Davies, R.A. Henderson, D.L. Hughes, K.E. Oglieve, J. Chem. Soc. Dalton
Trans. (1988) 425e432.
[42] J.S. Zhang, Y.J. Lin, G.-X. Jin, Dalton Trans (2009) 111e118.
[43] O. Crespo, M.C. Gimeno, P.G. Jones, A. Laguna, M.D. Villacampa, Angew. Chem.
Int. Ed. 36 (1997) 993e995.
[7] S. Liu, G.L. Wang, G.-X. Jin, Dalton Trans. (2008) 425e432.
[8] R.L. Julius, O.K. Farha, J. Chiang, L.J. Perry, M.F. Hawthorne, Proc. Natl. Acad. Sci.
104 (2007) 4808e4813.
[44] D.A. Evans, R.J. Thomson, J. Am. Chem. Soc. 127 (2005) 10506e10507.
[9] Z.Z. Qiu, Z.W. Xie, J. Am. Chem. Soc. 131 (2009) 2084e2085.
[45] D.P. Zhang, J.M. Dou, D.C. Li, D.Q. Wang, Acta Crystallogr.
E 63 (2007)
[10] A.I. Stoica, C. Viñas, F. Teixidor, Chem. Commun. (2008) 6492e6494.
[11] P. Cígler, M. Kozísek, P. Rezácová, J. Brynda, Z. Otwinowski, J. Pokornc, J. Plesek,
ꢁ
ꢁ ꢁ
ꢁ
ꢁ
ꢁ
m1086em1088.
ꢁ
ꢁ
ꢁ
ꢁ
[46] C. Bianchini, H.M. Lee, A. Meli, W. Oberhauser, M. Peruzzini, F. Vizza, Organ-
ometallics 21 (2002) 16e33.
[47] Y.C. Neo, J.S.L. Yeo, P.M.N. Low, S.W. Chien, T.C.W. Mak, J.J. Vittal, T.S.A. Hor, J.
Org. Chem. 658 (2002) 159e168.
[48] D.P. Gates, P.S. White, M. Brookhart, Chem. Commun. (2000) 47e48.
[49] P.J. Stang, D.H. Cao, G.T. Poulter, A.M. Arif, Organometallics 14 (1995)
1110e1114.
B. Grüner,L. Dolecková-Maresová, M. Mása, J. Sedlácek,J. Bodem, H.G. Kräusslich,
V. Král, J. Konvalinka, Proc. Natl. Acad. Sci. 102 (2005) 15394e15399.
[12] D.H. Wu, Y.G. Li, L. Han, Y.Z. Li, H. Yan, Inorg. Chem. 47 (2008) 6524e6531.
[13] D.H. Wu, C.H. Wu, Y.Z. Li, D.D. Guo, X.M. Wang, H. Yan, Dalton Trans. (2009)
285e290.
[14] B.H. Xu, X.Q. Peng, Y.Z. Li, H. Yan, Chem. Eur. J. 14 (2008) 9347e9356.
[15] G.-X. Jin, Coord. Chem. Rev. 248 (2004) 587e602.
[50] J.M. Dou, D.P. Zhang, D.C. Li, D.Q. Wang, Polyhedron 26 (2007) 719e724.
[51] G.L.L. Ward, J.R. Pipal, Inorg Synth 13 (1972) 154e164.
[52] R.P. Alexander, H. Schroeder, Inorg. Chem. 22 (1963) 1107e1110.
[53] Sheldrick GM. SHELXTL reference manual, version 6.10, Germany; 2000.
[16] J.Q. Wang, L.H. Weng, G.-X. Jin Rev, Inorg. Chem. 25 (2005) 55e66.
[17] S. Liu, Y.F. Han, G.-X. Jin, Chem. Soc. Rev. 36 (2007) 1543e1560.
[18] G.-X. Jin, J.Q. Wang, C. Zhang, L.H. Weng, M. Herberhold, Angew. Chem. Int. Ed.
44 (2005) 259e262.