Two 1D [CuxIx]-based coordination polymers of tetraphosphine ligands

Article abstract of DOI:10.1016/j.inoche.2009.08.014

Diffusion reactions of CuI with N,N,N′,N′-tetra(diphenylphosphanylmethyl)ethylene diamine) (dppeda) and 1,4-N,N,N′,N′-tetra(diphenylphosphanylmethyl)benzene diamine (dpppda) in MeCN/toluene in a zigzag glass tube or solvothermal reactions of CuI and dpped

Full text of DOI:10.1016/j.inoche.2009.08.014

Inorganic Chemistry Communications 12 (2009) 1031–1034
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Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Two 1D [CuxIx]-based coordination polymers of tetraphosphine ligands
Ni-Ya Li a, Zhi-Gang Ren a, Dong Liu a, Jing Wang a, Ming Dai a, Hong-Xi Li a, Jian-Ping Lang a,b,
*
a Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Suzhou University, Suzhou 215123, Jiangsu, PR China
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, PR China
a r t i c l e i n f o
a b s t r a c t
Diffusion reactions of CuI with N,N,N0,N0-tetra(diphenylphosphanylmethyl)ethylene diamine) (dppeda)
and 1,4-N,N,N0,N0-tetra(diphenylphosphanylmethyl)benzene diamine (dpppda) in MeCN/toluene in a zig-
zag glass tube or solvothermal reactions of CuI and dppeda or dpppda in MeCN produced two [CuxIx]-
based coordination polymers, [Cu2I2(dppeda)]ꢀ2MeCN (1ꢀ2MeCN) and [Cu4I4(dpppda)]ꢀMeCN (2ꢀMeCN),
respectively. Both compounds were characterized by elemental analysis, IR spectroscopy, 1H and
31P{1H} NMR, ESI-MS and thermogravimetric analysis, and their structures were determined by single
Article history:
Received 13 July 2009
Accepted 14 August 2009
Available online 19 August 2009
Keywords:
Copper(I)
Coordination polymer
Tetraphosphine
Crystal structure
crystal X-ray diffraction. In 1, [Cu2I2] cores are interconnected by dppeda ligands in a
end mode to form a 1D chain, while in 2 stair-like [Cu4I4] cores are linked by dpppda ligands in a unique
Z-shaped
g2 side-by-side mode to produce the other kind of 1D chain.
l- :
g2 g2 end-to-
l- :
g2
Ó 2009 Elsevier B.V. All rights reserved.
In the past decades, the design and synthesis of multi-phos-
phine ligands have attracted much attention [1–8] due to their ver-
satile ligating capability as well as rich structural chemistry and
unique physical and chemical properties of their metal complexes
[9–16]. Among the multiphosphine ligands, several tetraphosphine
ligands and their metal complexes that showed interesting lumi-
nescent properties, catalytic and anticancer performances, have
been extensively investigated [17–20]. In the case of IB metals,
the tetraphosphine ligands could react with Au(I) and Ag(I) salts
to form luminescent Au(I) complexes [20] and Ag(I) complexes
(cage-like) [11–13]. However, synthesis of Cu(I) complexes with
tetraphosphine ligands have been virtually not explored, though
a great number of Cu(I) complexes with diphosphines [3–5] were
reported.
Recently, we have also been interested in the preparation of
coinage metal complexes with tetraphosphines. N,N,N0,N0-
tetra(diphenylphosphanylmethyl)ethylene diamine) (dppeda) was
used to react with Ag(I) salts to produce a dinuclear Ag(I) complex
with a molecular basket structure and a polymeric complex (2D
layer) [21]. As an extension of this study and an exploration of
the coordination chemistry of tetraphosphines towards Cu(I), we
employed CuI to react with dppeda and its analogue 1,4-N,N,
N0,N0-tetra(diphenylphosphanylmethyl)benzene diamine (dpppda),
which resulted in the formation of two different [CuxIx]-based
coordination polymers [Cu2I2(dppeda)]ꢀ2MeCN (1ꢀ2MeCN) and
[Cu4I4(dpppda)]ꢀMeCN (2ꢀMeCN). Herein we report their synthesis
and structural characterization.
Directly mixing a solution of CuI in MeCN with a solution of
dppeda or dpppda in toluene gave rise to an instant white precip-
itate. Attempts to recrystallize it failed due to its low solubility in
common organic solvents. Therefore we decided to employ other
strategies to prepare Cu/tetraphosphine complexes. One method
is the diffusion reactions in a zigzag tube we developed recently
[22]. Stepwisely loading a solution of dppeda or dpppda in toluene,
a mixed solution of toluene and MeCN as a buffer band, an acento-
nitrile solution of CuI and diethyl ether followed by leaving it at
ambient temperature for 10 days afforded 1ꢀ2MeCN (61% yield)
or 2ꢀMeCN (56% yield) [23]. The other is the solvothermal reactions
in sealed glass tube. Reactions of CuI with dppeda or dpppda in
MeCN at 100 °C for one day produced 1ꢀ2MeCN and 2ꢀMeCN in
somewhat higher yields (79% for 1ꢀ2MeCN and 61% for 2ꢀMeCN).
In both cases, changing the molar ratios of tetraphosphines and
CuI in 1: 1–4 yielded the same compound. Crystals of 1ꢀ2MeCN
and 2ꢀMeCN easily lost solvent when being taking out of their
mother liquor. When the solvated MeCN molecules in 1ꢀ2MeCN
and 2ꢀMeCN were removed in vacuo, 1 and 2 were stable towards
air and moisture, and slightly soluble in DMF and DMSO. The ele-
mental analyses were consistent with their chemical formulae.
The IR spectra of 1 and 2 show the stretching vibrations of the
phenyl groups at ꢁ1600, 1482 and 1430 cmꢂ1. The 1H NMR spectra
showed signals related to protons of the ethylene group (2.73 ppm
for 1), the methylene groups (3.64 ppm for 1 and 3.34 ppm for 2),
the –NC6H4N– group (5.84 ppm for 2) and the phenyl groups
(7.09–7.60 ppm for 1 and 7.18–7.67 ppm for 2), respectively. In
the 31P{1H} NMR spectra (Figs. S1 and S2), there existed the chem-
ical shifts from ꢂ25.30 ppm (1) to ꢂ28.5 ppm (dppeda) or from
* Corresponding author. Address: Key Laboratory of Organic Synthesis of Jiangsu
Province, College of Chemistry, Chemical Engineering and Materials Science, Suzhou
University, Suzhou 215123, Jiangsu, PR China. Tel./fax: +86 512 65882865.
E-mail address: jplang@suda.edu.cn (J.-P. Lang).
1387-7003/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2009.08.014

1032
N.-Y. Li et al. / Inorganic Chemistry Communications 12 (2009) 1031–1034
ꢂ24.56 ppm (2) to ꢂ26.63 ppm (dpppda), which may be due to the
coupling between the 31P and 63Cu(65Cu) nuclei. The identities of
both compounds were confirmed by X-ray crystallography [24].
the midpoint of the N(1)ꢀ ꢀ ꢀN(1A) contact (2) (Fig. 2). Cu(1) is coor-
dinated by one P, -I and two 3-I atoms, adopting a distorted tet-
rahedron geometry, while Cu(2) by one P, -I and one 3-I atoms,
adopting a planar trigonal geometry. The Cu(1)ꢀ ꢀ ꢀCu(1A) and the
Cu(1)ꢀ ꢀ ꢀCu(2) separations are 3.523(1) Å and 3.302(1) Å, which ex-
clude any metal–metal interactions. For tetrahedrally-coordinated
l
l
l
l
ꢀ
1ꢀ2MeCN and 2ꢀMeCN crystallize in the triclinic space group P1,
and the asymmetric unit of 1 contains half of one [Cu2I2(dppeda)]
molecule and one MeCN solvent molecule while that of 2 has half
of one [Cu4I4(dpppda)] molecule and half of one MeCN solvent
molecule [24]. In 1, two Cu(I) and two I atoms form a [Cu2I2] core
with a crystallographic center of symmetry being at the midpoint
of Cu(1)ꢀ ꢀ ꢀCu(1A) contact (1) (Fig. 1). Each Cu(I) atom is tetrahe-
Cu, the mean Cu(1)–
that of Cu(1)– -I(2) bond and that of the corresponding ones in
[Cu4I4(PPh3)4] (2.685(3) Å) [29]. The trigonally-coordinated
Cu(2)– 3-I(1) and Cu(2)– -I(2) bond lengths are almost the same,
l3-I bond length (2.7460(14) Å) is longer than
l
l
l
drally coordinated to two
Cu(1)ꢀ ꢀ ꢀCu(1A) contact (3.175(1) Å) is too long to include any
metal–metal interactions. The mean Cu– -I and Cu–P bond lengths
(2.6582(9) Å vs. 2.2776(13) Å) are close to those of the correspond-
ing ones in [Cu( -I)(L)]2 (2.662(2) Å vs. 2.272(1) Å for L = bis
l-I atoms and two P atoms. The
but are in-between those of the corresponding ones of
[Cu4I4(PPh3)4] (2.559(3) Å) and 1. The mean Cu–P bond length
(2.240(3) Å) is in between that of 1 and that of [Cu4I4(PPh3)4]
(2.235(2) Å).
l
l
From a topological view, each [Cu2I2] core in 1 or [Cu4I4] core in
2 connects its equivalent ones via dppeda or dpppda bridges to
form a 1D chain extended along the b (1) or a (2) axis. The adjacent
chains are 12.37 Å apart with MeCN solvent molecules lying be-
tween the chains. The different coordination modes of dppeda
and dpppda towards Cu(I) deserve comments. It seems like that
the spacer of the tetraphospine ligand influences its coordination
modes. Relative to the –CH2CH2– spacer in dppeda, the phenyl
spacer in dpppda is longer and more rigid. Therefore, dppeda in 1
(diphenylphosphino)propane) [3], 2.635(3) Å vs. 2.281(2) Å for
L = bis(diphenylphosphino)butane [26].
In 2, four copper(I) centers are held together via two doubly-
bridging and two triply-bridging iodides to form a stair-like Cu4I4
core [27,28], which has a crystallographic center of symmetry at
has a smaller side-space and takes a
l- :
g2 g2 end-to-end mode
Fig. 2. View of a section of the 1D chain of 2 extending along the a-axis. All
hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (°):
Cu(1)–P(1) 2.247(3); Cu(2)–P(2A) 2.238(3); Cu(1)–I(1) 2.7493(16); Cu(1)–I(2)
2.6795(14); Cu(1)–I(1B) 2.7427(14); Cu(2)–I(1) 2.6135(14); Cu(2)–I(2)
2.6137(15); P(1)–Cu(1)–I(1) 121.07(8); P(1)–Cu(1)–I(2) 119.97(7); P(1)–Cu(1)–
I(1B) 110.58(8); I(1)–Cu(1)–I(2) 98.85(5); I(1)–Cu(1)–I(1B) 100.19(5); I(2)–Cu(1)–
I(1B) 103.11(5); P(2A)–Cu(2)–I(1) 129.87(7); P(2A)–Cu(2)–I(2) 124.96(8); I(1)–
Cu(2)–I(2) 104.17(5). Symmetry codes: (A) 1 ꢂ x, 1 ꢂ y, 1 ꢂ z; (B) ꢂx, 1 ꢂ y, 1 ꢂ z.
Fig. 1. View of a section of the 1D chain of 1 extending along the b-axis. All
hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (°):
Cu(1)–P(1) 2.2764(13); Cu(1)–P(2) 2.2788(10); Cu(1)–I(1) 2.6664(9); Cu(1)–I(1B)
2.6500(9); P(1)–Cu(1)–P(2) 103.10(4); P(1)–Cu(1)–I(1) 105.42(4); P(1)–Cu(1)–I(1B)
109.20(4); P(2)–Cu(1)–I(1) 108.21(4); P(2)–Cu(1)–I(1B) 123.02(4); I(1)–Cu(1)–I(1B)
106.66(2). Symmetry codes: (A) ꢂ1 ꢂ x, 1 ꢂ y, ꢂz; (B) ꢂ1 ꢂ x, ꢂy, ꢂz.

N.-Y. Li et al. / Inorganic Chemistry Communications 12 (2009) 1031–1034
1033
free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.
html or from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223 336 033; or
e-mail: deposit@ccdc.cam.ac.uk. Supplementary data associated
with this article can be found, in the online version, at doi:10.
1016/j.inoche.2009.08.014.
Ph2P
Ph2P
Ph2
P
Ph2
P
N
N
N
N
P
P
Ph2
Ph2
PPh2
References
end-to-end
Ph2P
[1] J.C. Hierso, R. Amardeil, E. Bentabet, R. Broussier, B. Gautheron, P. Meunier, P.
Kalck, Coord. Chem. Rev. 236 (2003) 143.
[2] J.C. Hierso, A. Fihri, V.V. Ivanov, B. Hanquet, N. Pirio, B. Donnadieu, B. Rebiere, R.
Amardeil, P. Meunier, J. Am. Chem. Soc. 126 (2004) 11077.
side-by-side
[3] Effendy, C.D. Nicola, M. Fianchini, C. Pettinari, B.W. Skelton, N. Somers, A.H.
White, Inorg. Chim. Acta 358 (2005) 763.
[4] J.F. Zhang, M.M. Yu, X.J. Zhao, X.M. Qu, W.F. Fu, Acta Cryst. E62 (2006) m3498.
[5] S.P. Neo, Z.Y. Zhou, T.C.W. Mark, T.S.A. Hor, Dalton Trans. (1994) 3451.
[6] S.W. Kohl, F.W. Heinemann, M. Hummert, W. Bauer, A. Grohmann, Dalton
Trans. (2006) 5583.
[7] D. Saravanabharathi, Monika, P. Venugopalan, A.G. Samuelson, Polyhedron 21
(2002) 2433.
[8] M. Rodriguez-Zubiri, V. Gallo, J. Rose, R. Welter, P. Braunstein, Chem. Commun.
(2008) 64.
[9] X.L. Xu, M. Nieuwenhuyzen, S.L. James, Angew. Chem., Int. Ed. 41 (2002) 764.
[10] J. Zhang, P.W. Miller, M. Nieuwenhuyzen, S.L. James, Chem. Eur. J. 12 (2006)
2448.
[11] J. Zhang, M. Nieuwenhuyzen, J.P.H. Charmant, S.L. James, Chem. Commun.
(2004) 2808.
Scheme 1. The end-to-end coordination mode of dppda in 1 (left) and the side-by-
side coordination mode of dpppa in 2 (right).
(Scheme 1) [17–21] to chelate at each of the two Cu atoms of the
[Cu2I2] core via two Cu–P bonds. On the contrary, dpppda in 2
adopts a rare Z-shaped
l- :
g2 g2 side-by-side mode (Scheme 1) to
have more side-space to coordinate at the four Cu(I) centers of
the [Cu4I4] core via four Cu–P bonds. Such a coordination mode
was uncommon in the chemistry of tetraphosphines [20] because
one tetraphospine ligand usually employs a
mode to bind to only two metal centers [15,30,31].
l- :
g2 g2 side-by-side
In order to gain more insight into the stability of 1ꢀ2MeCN and
2ꢀMeCN in solution and in solid state, we measured their ESI-MS
and made their thermogravimetric analysis. The positive ESI-MS
spectra of 1ꢀ2MeCN and 2ꢀMeCN in DMSO (ionized by 0.1 M HCl)
revealed a set of peaks assignable to [Cu(DMSO)2]+ (m/z = 219.1),
[Cu(PPh2)]+ (m/z = 247.1), [Cu2ICl3]+ (m/z = 359.2), [Cu2I(PPh2)]+
(m/z = 437.1), [CuI2(PPh2)]+ (m/z = 501.2), [Cu3I4 + H]+ (m/z =
699.2), and [Cu4I3(DMSO)]+ (m/z = 713.1) (Figs. S3 and S4). The
existence of these cationic fragments implied that the polymeric
chains of 1 and 2 may not be stable in solution under the acidic
and mass conditions, and that the resulting cations may be formed
by decomposition of the [Cu2I2] or [Cu4I4] core and the tetraphos-
phine ligands followed by recombination of the decomposed
species.
The thermogravimetric analysis showed that solids 1 and 2
were stable at ambient temperature (Fig. S5). Their TGA curves dis-
played three stages of decomposition. The first weight loss of 6.2%
(1ꢀ2MeCN) and 2.3% (2ꢀMeCN) in the region of 60–110 °C or 110–
250 °C corresponds to the removal of the MeCN solvent molecules
in 1ꢀ2MeCN or 2ꢀMeCN. The second weight loss (33.7% for 1ꢀ2MeCN
and 52.0% for 2ꢀMeCN) in the region of 270–430 °C (1ꢀ2MeCN) or
280–510 °C (2ꢀMeCN) amounts roughly to the loss of the tetra-
phosphine ligands in 1ꢀ2MeCN or 2ꢀMeCN. Upon heating up to
660 °C (1ꢀ2MeCN) or 780 °C (2ꢀMeCN), all iodine and phosphorous
were removed and the final residue was assumed to be copper
(9.7% for 1ꢀ2MeCN and 14.9% for 2ꢀMeCN) according to X-ray fluo-
rescence analysis.
[12] J. Zhang, X.L. Xu, S.L. James, Chem. Commun. (2006) 4218.
[13] S.L. James, D.M.P. Mingos, A.J.P. White, D.J. Williams, Chem. Commun. (1998)
2323.
[14] P.W. Miller, M. Nieuwenhuyzen, J.P.H. Charmant, S.L. James, Inorg. Chem. 47
(2008) 8367.
[15] C. Ganesamoorthy, M.S. Balakrishna, J.T. Mague, H.M. Tuononen, Inorg. Chem.
47 (2008) 7035.
[16] C. Bianchini, A. Meli, M. Peruzzini, F. Vizza, S. Moneti, V. Herrera, R.A. Sanchez-
Delgado, J. Am. Chem. Soc. 116 (1994) 4370.
[17] A.L. Balch, M.M. Olmstead, S.P. Rowley, Inorg. Chim. Acta 168 (1990) 255.
[18] J.Y. Zhang, J.J. Vittal, W. Henderson, J.R. Wheaton, I.H. Hall, T.S.A. Hor, Y.K. Yan,
J. Organomet. Chem. 650 (2002) 123.
[19] L.C. Song, F.H. Su, Q.M. Hu, E. Grigiotti, P. Zanello, Eur. J. Inorg. Chem. (2006)
422.
[20] E.J. Fernández, A. Laguna, J.M. López-de-Luzuriaga, M. Monge, M. Montiel, M.E.
Olmos, R.C. Puelles, E. Sánchez-Forcada, Eur. J. Inorg. Chem. (2007) 4001.
[21] L. Li, Z.G. Ren, N.Y. Li, Y. Zhang, J.P. Lang, Inorg. Chim. Acta 362 (2009) 3910.
[22] J.X. Chen, X.Y. Tang, Y. Chen, W.H. Zhang, L.L. Li, R.X. Yuan, Y. Zhang, J.P. Lang,
Cryst. Growth Des. 9 (2009) 1461.
[23] Method 1: To a zigzag glass tube was carefully loaded in order a solution of
dppeda/dpppda (0.005 mmol) in toluene (1 mL), 5 mL of toluene and MeCN (v/
v = 1:1), a solution of CuI (0.01 mmol) in MeCN (1.5 mL), and 1 mL of diethyl
ether. The glass tube was left at ambient temperature for 10 days. Colorless
blocks of 1ꢀ2MeCN or 2ꢀMeCN were collected by filtration and washed with
toluene and MeCN (v/v = 2:1). Yield: 61% for 1ꢀ2MeCN or 56% for 2ꢀMeCN.
Method 2: To a Pyrex glass tube was added dppeda/dpppda (0.01 mmol), CuI
(0.02 mmol) and 1.0 mL of MeCN. The tube was then sealed and heated up to
100 °C for 24 h. After being cooled to ambient temperature at a rate of 5 °C/h,
the resulting colorless blocks of 1ꢀ2MeCN or 2ꢀMeCN were formed. Yield: 79%
for 1ꢀ2MeCN or 61% for 2ꢀMeCN. For 1: Anal. Calcd for C54H52N2P4Cu2I2: C,
52.57; H, 4.25; N, 2.27. Found: C, 52.51; H, 4.31; N, 2.20%. IR (KBr, cmꢂ1): 3441
(m), 3046 (m), 2924 (w), 1966 (w), 1895 (w), 1885 (w), 1570 (m), 1482 (s),
1433 (s), 1370 (w), 1257 (w), 1184 (w), 1097 (s), 1026 (m), 859 (s), 739 (s), 692
(s), 509 (s), 482 (m). 1H NMR (400 MHz, DMSO-d6, ppm): d 7.09–7.60 (m, 40H,
–Ph), 3.64 (s, 8H, –PCH2N–), 2.73 (s, 4H, –CH2CH2–). 31P NMR (400 MHz,
DMSO-d6, ppm): d ꢂ25.30 (s, –PPh2). For 2, Anal. Calcd for C58H52N2P4Cu4I4: C,
41.90; H, 3.15; N, 1.68. Found: C, 41.81; H, 3.13; N, 1.66%. IR (KBr, cmꢂ1): 3441
(m), 3049 (m), 2920 (w), 1960 (w), 1888 (w), 1608 (w), 1517 (s) 1482 (s), 1435
(s), 1348 (w), 1246 (m), 1217 (m), 1137 (m), 1098 (s), 1026 (m), 998 (m), 863
(m), 795 (m), 743 (s), 693 (s), 508 (s), 480 (m), 440 (w). 1H NMR (400 MHz,
DMSO-d6, ppm): d 7.18–7.67 (m, 40H, –Ph), 5.84 (m, 4H, –Ph–), 3.34(s, 8H, –
PCH2N–). 31P NMR (400 MHz, DMSO-d6, ppm): d ꢂ24.56 (s, –PPh2).
[24] Crystal data for 1ꢀ2MeCN: C58H58N4P4Cu2I2, Mr = 1315.84, colorless crystal
Acknowledgements
This work was supported by the National Natural Science Foun-
dation of China (20525101 and 20871088), the State Key Labora-
tory of Organometallic Chemistry of Shanghai Institute of Organic
Chemistry (2008–25), the Program of Innovative Research Team
of Suzhou University and the ‘‘Soochow Scholar” Program of Suz-
hou University. We are grateful to the editor and the reviewers
for their suggestions.
ꢀ
(0.10 ꢃ 0.40 ꢃ 0.28 mm), trinilic, space group P1, a = 8.4994(17) Å,
b = 13.175(3) Å, c = 13.383(3) Å,
a = 67.52(3)°, b = 82.70(3)°, c = 84.15(3)°,
V = 1371.1(5) Å3, Z = 1, Dc = 1.594 g cmꢂ3, F(0 0 0) = 658 and
l ,
= 2.060 mmꢂ1
T = 193 K, 8693 reflections collected, 4729 unique (Rint = 0.0307). R1 = 0.0303,
wR2 = 0.0621 and S = 0.983 based on 4083 observed reflections with
I > 2.00
crystal (0.40 ꢃ 0.16 ꢃ 0.10 mm), trinilic, space group P1, a = 10.363(2) Å,
b = 12.367(3) Å, c = 13.540(3) Å, = 108.27(3)°, b = 106.76(3)°, = 91.03(3)°,
V = 1566.6(7) Å3, Z = 1, Dc = 1.806 g cmꢂ3, F(0 0 0) = 924 and = 3.451 mmꢂ1
r(I). Crystal data for 2ꢀMeCN: C60H55N3P4Cu4I4, Mr = 1703.71, orange
ꢀ
a
c
Appendix A. Supplementary material
l
,
T = 193 K, 15,313 reflections collected, 5710 unique (Rint = 0.0480). R1 = 0.0580,
wR2 = 0.1311 and S = 1.107 based on 4234 observed reflections with
CCDC 708477 and 708478 contain the supplementary crystallo-
graphic data for 1ꢀ2MeCN and 2ꢀMeCN. These data can be obtained
I > 2.00r(I). Data collections were performed on a Rigaku Mercury CCD

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N.-Y. Li et al. / Inorganic Chemistry Communications 12 (2009) 1031–1034
diffractomer with graphite-monochromated Mo K
a
radiation (k = 0.71073 Å).
[27] E. Cariati, D. Roberto, R. Ugo, P.C. Ford, S. Galli, A. Sironi, Inorg. Chem. 44 (2005)
4077.
[28] T. Wu, M. Li, D. Li, X.C. Huang, Cryst. Growth Des. 44 (2007) 4077.
[29] M.R. Churchill, B.G. DeBoer, D.J. Donovan, Inorg. Chem. 14 (1975) 617.
[30] M.R. Mason, C.M. Duff, L.L. Miller, R.A. Jacobson, J.G. Verkade, Inorg. Chem. 31
(1992) 2746.
The crystal structures were solved by direct methods and refined with full-
matrix least-squares technique using SHELXL-97 program [25]. All non-
hydrogen atoms were refined anisotropically. Hydrogen atoms were placed in
geometrically idealized positions and constrained to ride on their parent
atoms.
[25] G.M. Sheldrick, Acta Cryst. A 64 (2008) 112.
[26] A. Tsuboyama, K. Kuge, M. Furugori, S. Okada, M. Hoshino, K. Ueno, Inorg.
Chem. 46 (2007) 1992.
[31] N. Feeder, J.F. Geng, P.G. Goh, B.F.G. Johnson, C.M. Martin, D.S. Shephard, W.Z.
Zhou, Angew. Chem., Int. Ed. 39 (2000) 1661.