Hexa­kis­(dimethyl sulfoxide-κO)nickel(II) bis­(2,2-dicyano­ethene-1,1-dithiol­ato-κ2S,S′)nickelate(II)

Niu, M.; Fan, S.; Liu, G.

doi:10.1107/S1600536811053827

metal-organic compounds

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Volume 68| Part 1| January 2012| Page m67

doi:10.1107/S1600536811053827

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Hexakis(dimethyl sulfoxide-κO)nickel(II) bis(2,2-dicyanoethene-1,1-dithiolato-κ²S,S′)nickelate(II)

Meiju Niu,^a ^* Shumei Fan ^b and Guihua Liu ^a

^aSchool of Chemistry and Chemical Engineering, Liaocheng University, Shandong 252059, People's Republic of China, and ^bDongchang College Liaocheng University, Shandong 252000, People's Republic of China
^*Correspondence e-mail: niumeiju@163.com

(Received 28 November 2011; accepted 14 December 2011; online 21 December 2011)

The reaction of NiCl₂·6H₂O with sodium 2,2-dicyanoethene-1,1-dithiolate [Na₂(i-mnt)] in dimethyl sulfoxide produces the title complex, [Ni(C₂H₆OS)₆][Ni(C₄N₂S₂)₂]. There is half each of an [Ni(C₂H₆OS)₆]²⁻ complex anion and an [Ni{(CH₃)₂SO}₆]²⁺ complex cation in the asymmetric unit. The i-mnt ligand coordinates in a bidentate manner to the Ni atom in the anion through the two chelating S atoms in an approximate square-planar geometry. The Ni atom in the complex cation has an octahedral coordination environment with six dimethyl sulfoxide molecules as ligands.

Related literature

For related structures, see Gao et al. (2004 , 2005 ); Yu et al. (2005 ); Chen & Yu (2005 ).

Experimental

Crystal data

[Ni(C₂H₆OS)₆][Ni(C₄N₂S₂)₂]
M_r = 866.55
Monoclinic, P 2₁ /c
a = 8.3368 (10) Å
b = 12.6763 (17) Å
c = 18.710 (2) Å
β = 102.466 (2)°
V = 1930.6 (4) Å³
Z = 2
Mo Kα radiation
μ = 1.55 mm⁻¹
T = 298 K
0.50 × 0.48 × 0.05 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.511, T_max = 0.921
9458 measured reflections
3379 independent reflections
2328 reflections with I > 2σ(I)
R_int = 0.054

Refinement

R[F² > 2σ(F²)] = 0.038
wR(F²) = 0.095
S = 1.06
3379 reflections
199 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Ni1—O3	2.052 (2)
Ni1—O2	2.060 (3)
Ni1—O1	2.064 (2)
Ni2—S4	2.2010 (11)
Ni2—S5	2.2030 (11)

O3—Ni1—O2	90.14 (11)
S4—Ni2—S5	78.96 (4)

Data collection: SMART (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811053827/vm2141sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811053827/vm2141Isup2.hkl

checkCIF report

Comment top

The bridging ligand 1,1-dicyanoethene-2,2-dithiolate has been attracting more and more attention due to its delocalized

π electron system able to build special planar conjugated structures (Yu et al., 2005). The title complex consists of one [Ni(i-mnt)₂]^2- (where i-mnt is 1,1-dicyanoethene-2,2-dithiolate) complex anion and one [Ni((CH₃)₂SO)₆]²⁺ complex cation. For the [Ni(i-mnt)₂]^2- complex anion, the NiS₄ group is square planar and tortiled slightly at an angle of 2.90 (14)° with respect to the plane of i-mnt ligand (Chen et al., 2005). FourNi-S bonds present two comparable distances of 2.2010 (11) and 2.2030 (11)Å, similar to the Ni-S distance of 2.172 (3)

Å in [K(N18C6)]₂[Ni(mnt)₂] (Gao et al., 2004). The average S-C, C≡N, C-C and C=C bond lengths were 1.717, 1.141, 1.418, 1.379 Å, respectively (Gao et al., 2005). The [Ni((CH₃)₂SO)₆]²⁺ complex cation contains a nickel with six-coordinated octahedral geometry.

Related literature top

For related structures, see Gao et al. (2004, 2005); Yu et al. (2005); Chen et al. (2005) .

Experimental top

The title compound, [Ni((CH₃)₂SO)₆][Ni(i-mnt)₂] was synthesizd by the reaction of 0.05 mmol NiCl₂.6H₂O and 0.1 mmol Na₂(i-mnt)(1,1-dicyanoethene-2,2-dithiolate sodium) in 5 ml water. The solution was stirred for 2 hours and then filtered. The precipitate was dissolved in 10ml Dimethyl Sulfoxide. After slow evaporation of the solution over one month, deep green crystals suitable for X-ray diffraction were obtained (56.8%, m.p. 527-529 K).

Computing details top

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of the title compound with atom labels and 40% probability displacement ellipsoids for non-H atoms. Symmetry codes: (i) -x + 1,-y + 1,-z + 1, (ii) -x + 2, -y, -z + 1.

Hexakis(dimethyl sulfoxide-κO)nickel(II) bis(2,2-dicyanoethene-1,1-dithiolato-κ²S,S')nickelate(II) top

Crystal data top

C₁₂H₃₆NiO₆S₆²⁺·C₈N₄NiS₄²⁻	F(000) = 896
M_r = 866.55	D_x = 1.491 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2760 reflections
a = 8.3368 (10) Å	θ = 2.5–24.3°
b = 12.6763 (17) Å	µ = 1.55 mm⁻¹
c = 18.710 (2) Å	T = 298 K
β = 102.466 (2)°	Needle, green
V = 1930.6 (4) Å³	0.50 × 0.48 × 0.05 mm
Z = 2

Data collection top

Bruker SMART CCD area-detector diffractometer	3379 independent reflections
Radiation source: fine-focus sealed tube	2328 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.054
phi and ω scans	θ_max = 25.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
T_min = 0.511, T_max = 0.921	k = −12→15
9458 measured reflections	l = −22→18

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.095	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0275P)² + 1.0073P] where P = (F_o² + 2F_c²)/3
3379 reflections	(Δ/σ)_max = 0.001
199 parameters	Δρ_max = 0.30 e Å⁻³
0 restraints	Δρ_min = −0.35 e Å⁻³

Crystal data top

C₁₂H₃₆NiO₆S₆²⁺·C₈N₄NiS₄²⁻	V = 1930.6 (4) Å³
M_r = 866.55	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.3368 (10) Å	µ = 1.55 mm⁻¹
b = 12.6763 (17) Å	T = 298 K
c = 18.710 (2) Å	0.50 × 0.48 × 0.05 mm
β = 102.466 (2)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3379 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2328 reflections with I > 2σ(I)
T_min = 0.511, T_max = 0.921	R_int = 0.054
9458 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.038	0 restraints
wR(F²) = 0.095	H-atom parameters constrained
S = 1.06	Δρ_max = 0.30 e Å⁻³
3379 reflections	Δρ_min = −0.35 e Å⁻³
199 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.5000	0.5000	0.5000	0.02973 (18)
Ni2	1.0000	0.0000	0.5000	0.0415 (2)
N1	0.7064 (6)	0.2565 (4)	0.2505 (2)	0.0863 (15)
N2	1.1494 (6)	0.0945 (4)	0.2174 (2)	0.0751 (13)
O1	0.4945 (3)	0.64165 (18)	0.44513 (13)	0.0367 (6)
O2	0.7372 (3)	0.47506 (19)	0.48840 (15)	0.0440 (7)
O3	0.4122 (3)	0.41769 (19)	0.40520 (13)	0.0436 (7)
S1	0.62727 (13)	0.72370 (8)	0.46849 (5)	0.0412 (3)
S2	0.78272 (12)	0.36249 (8)	0.47193 (5)	0.0385 (3)
S3	0.32535 (13)	0.47016 (8)	0.33476 (5)	0.0391 (3)
S4	0.81754 (14)	0.08901 (9)	0.41999 (6)	0.0489 (3)
S5	1.10676 (15)	−0.00988 (9)	0.40228 (6)	0.0533 (3)
C1	0.5310 (7)	0.8291 (4)	0.5044 (3)	0.095 (2)
H1A	0.4416	0.8553	0.4675	0.142*
H1B	0.6092	0.8846	0.5198	0.142*
H1C	0.4898	0.8047	0.5456	0.142*
C2	0.6505 (7)	0.7821 (4)	0.3864 (2)	0.0732 (16)
H2A	0.6983	0.7320	0.3586	0.110*
H2B	0.7208	0.8426	0.3971	0.110*
H2C	0.5449	0.8036	0.3586	0.110*
C3	0.9350 (5)	0.3786 (3)	0.4198 (2)	0.0503 (11)
H3A	0.8874	0.4120	0.3741	0.075*
H3B	0.9777	0.3108	0.4106	0.075*
H3C	1.0224	0.4216	0.4465	0.075*
C4	0.9093 (6)	0.3174 (4)	0.5552 (2)	0.0585 (13)
H4A	0.9998	0.3651	0.5701	0.088*
H4B	0.9504	0.2484	0.5480	0.088*
H4C	0.8462	0.3144	0.5924	0.088*
C5	0.2206 (6)	0.3635 (4)	0.2835 (2)	0.0676 (14)
H5A	0.2961	0.3066	0.2827	0.101*
H5B	0.1756	0.3863	0.2343	0.101*
H5C	0.1334	0.3399	0.3057	0.101*
C6	0.4776 (6)	0.4904 (4)	0.2835 (2)	0.0600 (13)
H6A	0.5526	0.5440	0.3065	0.090*
H6B	0.4265	0.5123	0.2348	0.090*
H6C	0.5365	0.4258	0.2813	0.090*
C7	0.9525 (5)	0.0750 (3)	0.3630 (2)	0.0409 (10)
C8	0.9395 (5)	0.1255 (3)	0.2967 (2)	0.0427 (10)
C9	0.8105 (6)	0.1979 (4)	0.2706 (2)	0.0526 (12)
C10	1.0561 (6)	0.1086 (3)	0.2528 (2)	0.0522 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.0336 (4)	0.0269 (4)	0.0290 (4)	0.0013 (3)	0.0074 (3)	−0.0017 (3)
Ni2	0.0476 (5)	0.0370 (4)	0.0408 (4)	0.0016 (4)	0.0116 (3)	−0.0019 (3)
N1	0.092 (4)	0.077 (3)	0.076 (3)	0.030 (3)	−0.011 (3)	−0.008 (2)
N2	0.080 (3)	0.093 (3)	0.058 (3)	0.006 (3)	0.029 (2)	0.002 (2)
O1	0.0380 (16)	0.0297 (14)	0.0415 (14)	−0.0024 (12)	0.0067 (12)	0.0023 (12)
O2	0.0373 (17)	0.0336 (16)	0.0633 (18)	−0.0007 (12)	0.0155 (14)	−0.0079 (13)
O3	0.061 (2)	0.0358 (15)	0.0309 (14)	−0.0010 (14)	0.0039 (13)	−0.0047 (12)
S1	0.0402 (7)	0.0377 (6)	0.0461 (6)	−0.0039 (5)	0.0104 (5)	0.0007 (5)
S2	0.0339 (6)	0.0327 (6)	0.0497 (6)	0.0002 (4)	0.0104 (5)	−0.0077 (5)
S3	0.0409 (6)	0.0434 (6)	0.0325 (5)	0.0031 (5)	0.0071 (4)	−0.0050 (4)
S4	0.0502 (8)	0.0503 (7)	0.0486 (6)	0.0102 (5)	0.0157 (5)	−0.0005 (5)
S5	0.0537 (8)	0.0614 (8)	0.0473 (6)	0.0163 (6)	0.0161 (5)	0.0049 (6)
C1	0.094 (5)	0.053 (3)	0.155 (6)	−0.023 (3)	0.067 (4)	−0.048 (4)
C2	0.086 (4)	0.072 (3)	0.063 (3)	−0.032 (3)	0.018 (3)	0.015 (3)
C3	0.045 (3)	0.048 (3)	0.063 (3)	−0.003 (2)	0.022 (2)	−0.011 (2)
C4	0.067 (3)	0.049 (3)	0.056 (3)	0.014 (2)	0.004 (2)	0.000 (2)
C5	0.077 (4)	0.074 (3)	0.049 (3)	−0.025 (3)	0.008 (2)	−0.017 (3)
C6	0.062 (3)	0.064 (3)	0.061 (3)	−0.005 (3)	0.030 (3)	0.006 (2)
C7	0.045 (3)	0.035 (2)	0.041 (2)	−0.0014 (19)	0.0061 (19)	−0.0096 (18)
C8	0.045 (3)	0.042 (3)	0.041 (2)	0.002 (2)	0.008 (2)	−0.0053 (19)
C9	0.066 (3)	0.049 (3)	0.040 (2)	−0.003 (3)	0.005 (2)	−0.010 (2)
C10	0.065 (4)	0.051 (3)	0.040 (3)	−0.002 (2)	0.008 (2)	0.001 (2)

Geometric parameters (Å, º) top

Ni1—O3	2.052 (2)	S5—C7	1.716 (4)
Ni1—O3ⁱ	2.052 (2)	C1—H1A	0.9600
Ni1—O2ⁱ	2.060 (3)	C1—H1B	0.9600
Ni1—O2	2.060 (3)	C1—H1C	0.9600
Ni1—O1	2.064 (2)	C2—H2A	0.9600
Ni1—O1ⁱ	2.064 (2)	C2—H2B	0.9600
Ni2—S4	2.2010 (11)	C2—H2C	0.9600
Ni2—S4ⁱⁱ	2.2010 (11)	C3—H3A	0.9600
Ni2—S5ⁱⁱ	2.2030 (11)	C3—H3B	0.9600
Ni2—S5	2.2030 (11)	C3—H3C	0.9600
N1—C9	1.142 (6)	C4—H4A	0.9600
N2—C10	1.139 (5)	C4—H4B	0.9600
O1—S1	1.513 (3)	C4—H4C	0.9600
O2—S2	1.525 (3)	C5—H5A	0.9600
O3—S3	1.514 (3)	C5—H5B	0.9600
S1—C2	1.752 (4)	C5—H5C	0.9600
S1—C1	1.765 (5)	C6—H6A	0.9600
S2—C3	1.772 (4)	C6—H6B	0.9600
S2—C4	1.777 (4)	C6—H6C	0.9600
S3—C6	1.767 (4)	C7—C8	1.378 (5)
S3—C5	1.775 (4)	C8—C9	1.418 (6)
S4—C7	1.719 (4)	C8—C10	1.418 (6)

O3—Ni1—O3ⁱ	180.000 (1)	H1B—C1—H1C	109.5
O3—Ni1—O2ⁱ	89.86 (11)	S1—C2—H2A	109.5
O3ⁱ—Ni1—O2ⁱ	90.14 (11)	S1—C2—H2B	109.5
O3—Ni1—O2	90.14 (11)	H2A—C2—H2B	109.5
O3ⁱ—Ni1—O2	89.86 (11)	S1—C2—H2C	109.5
O2ⁱ—Ni1—O2	180.00 (15)	H2A—C2—H2C	109.5
O3—Ni1—O1	92.69 (9)	H2B—C2—H2C	109.5
O3ⁱ—Ni1—O1	87.31 (9)	S2—C3—H3A	109.5
O2ⁱ—Ni1—O1	90.01 (10)	S2—C3—H3B	109.5
O2—Ni1—O1	89.99 (10)	H3A—C3—H3B	109.5
O3—Ni1—O1ⁱ	87.31 (9)	S2—C3—H3C	109.5
O3ⁱ—Ni1—O1ⁱ	92.69 (9)	H3A—C3—H3C	109.5
O2ⁱ—Ni1—O1ⁱ	89.99 (10)	H3B—C3—H3C	109.5
O2—Ni1—O1ⁱ	90.01 (10)	S2—C4—H4A	109.5
O1—Ni1—O1ⁱ	180.0	S2—C4—H4B	109.5
S4—Ni2—S4ⁱⁱ	180.00 (5)	H4A—C4—H4B	109.5
S4—Ni2—S5ⁱⁱ	101.04 (4)	S2—C4—H4C	109.5
S4ⁱⁱ—Ni2—S5ⁱⁱ	78.96 (4)	H4A—C4—H4C	109.5
S4—Ni2—S5	78.96 (4)	H4B—C4—H4C	109.5
S4ⁱⁱ—Ni2—S5	101.04 (4)	S3—C5—H5A	109.5
S5ⁱⁱ—Ni2—S5	180.0	S3—C5—H5B	109.5
S1—O1—Ni1	121.20 (14)	H5A—C5—H5B	109.5
S2—O2—Ni1	116.83 (15)	S3—C5—H5C	109.5
S3—O3—Ni1	122.93 (15)	H5A—C5—H5C	109.5
O1—S1—C2	104.45 (19)	H5B—C5—H5C	109.5
O1—S1—C1	105.4 (2)	S3—C6—H6A	109.5
C2—S1—C1	99.2 (3)	S3—C6—H6B	109.5
O2—S2—C3	104.06 (18)	H6A—C6—H6B	109.5
O2—S2—C4	104.50 (18)	S3—C6—H6C	109.5
C3—S2—C4	99.1 (2)	H6A—C6—H6C	109.5
O3—S3—C6	105.8 (2)	H6B—C6—H6C	109.5
O3—S3—C5	102.88 (19)	C8—C7—S5	125.7 (3)
C6—S3—C5	98.3 (2)	C8—C7—S4	125.1 (3)
C7—S4—Ni2	85.42 (14)	S5—C7—S4	109.2 (2)
C7—S5—Ni2	85.44 (14)	C7—C8—C9	121.2 (4)
S1—C1—H1A	109.5	C7—C8—C10	121.3 (4)
S1—C1—H1B	109.5	C9—C8—C10	117.5 (4)
H1A—C1—H1B	109.5	N1—C9—C8	179.0 (5)
S1—C1—H1C	109.5	N2—C10—C8	179.7 (6)
H1A—C1—H1C	109.5

O3—Ni1—O1—S1	−142.43 (17)	Ni1—O3—S3—C5	−161.4 (2)
O3ⁱ—Ni1—O1—S1	37.57 (17)	S4ⁱⁱ—Ni2—S4—C7	−120 (100)
O2ⁱ—Ni1—O1—S1	127.71 (17)	S5ⁱⁱ—Ni2—S4—C7	173.58 (13)
O2—Ni1—O1—S1	−52.29 (17)	S5—Ni2—S4—C7	−6.42 (13)
O1ⁱ—Ni1—O1—S1	−139 (100)	S4—Ni2—S5—C7	6.44 (13)
O3—Ni1—O2—S2	−48.30 (17)	S4ⁱⁱ—Ni2—S5—C7	−173.56 (13)
O3ⁱ—Ni1—O2—S2	131.70 (17)	S5ⁱⁱ—Ni2—S5—C7	112 (14)
O2ⁱ—Ni1—O2—S2	13 (48)	Ni2—S5—C7—C8	170.5 (3)
O1—Ni1—O2—S2	−140.99 (17)	Ni2—S5—C7—S4	−8.58 (17)
O1ⁱ—Ni1—O2—S2	39.01 (17)	Ni2—S4—C7—C8	−170.5 (3)
O3ⁱ—Ni1—O3—S3	−178 (100)	Ni2—S4—C7—S5	8.59 (18)
O2ⁱ—Ni1—O3—S3	71.7 (2)	S5—C7—C8—C9	−177.2 (3)
O2—Ni1—O3—S3	−108.3 (2)	S4—C7—C8—C9	1.7 (6)
O1—Ni1—O3—S3	−18.3 (2)	S5—C7—C8—C10	1.6 (6)
O1ⁱ—Ni1—O3—S3	161.7 (2)	S4—C7—C8—C10	−179.4 (3)
Ni1—O1—S1—C2	145.1 (2)	C7—C8—C9—N1	26 (32)
Ni1—O1—S1—C1	−110.9 (3)	C10—C8—C9—N1	−153 (32)
Ni1—O2—S2—C3	149.93 (19)	C7—C8—C10—N2	79 (100)
Ni1—O2—S2—C4	−106.6 (2)	C9—C8—C10—N2	−102 (100)
Ni1—O3—S3—C6	95.9 (2)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+2, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₂H₃₆NiO₆S₆²⁺·C₈N₄NiS₄²⁻
M_r	866.55
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	8.3368 (10), 12.6763 (17), 18.710 (2)
β (°)	102.466 (2)
V (Å³)	1930.6 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	1.55
Crystal size (mm)	0.50 × 0.48 × 0.05

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.511, 0.921
No. of measured, independent and observed [I > 2σ(I)] reflections	9458, 3379, 2328
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.095, 1.06
No. of reflections	3379
No. of parameters	199
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.30, −0.35

Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top

Ni1—O3	2.052 (2)	Ni2—S4	2.2010 (11)
Ni1—O2	2.060 (3)	Ni2—S5	2.2030 (11)
Ni1—O1	2.064 (2)

O3—Ni1—O2	90.14 (11)	S4—Ni2—S5	78.96 (4)

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Nos. 20671048, 21041002).

References

Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chen, H. M. & Yu, H. L. (2005). Chin. J. Spectrosc. Lab. 22, 740–742. CAS Google Scholar
Gao, X. K., Dou, J. M. & Dong, F. Y. (2004). J. Inorg. Organomet. Polym. 14, 227–237. Web of Science CrossRef CAS Google Scholar
Gao, X. K., Dou, J. M. & Li, D. C. (2005). J. Mol. Struct. 733, 181–186. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yu, H. L., Chen, H. M. & Dou, J. M. (2005). Chin. J. Spectrosc. Lab. 22, 556–558. CAS Google Scholar

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