Crystal structure of di­chlorido­(2,2′:6′,2′′-terpyridine-κ3N,N′,N′′)zinc: a redeter­min­ation

Kong, C.-C.; Zhou, J.-Z.; Yu, J.-H.; Li, S.-L.

doi:10.1107/S1600536814023605

metal-organic compounds

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ISSN: 2056-9890

Volume 70| Part 11| November 2014| Pages m382-m383

doi:10.1107/S1600536814023605

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Crystal structure of dichlorido(2,2′:6′,2′′-terpyridine-κ³N,N′,N′′)zinc: a redetermination

Cheng-Cheng Kong,^a Jia-Zheng Zhou,^a Jian-Hua Yu ^a and Sheng-Li Li ^a ^*

^aDeparment of Chemistry, Anhui University, Hefei 230039, Peoples Republic of China, Key Laboratory of Functional Inorganic Materials, Chemistry, Hefei 230039, People's Republic of China
^*Correspondence e-mail: lsl1968@ahu.edu.cn

Edited by M. Weil, Vienna University of Technology, Austria (Received 21 October 2014; accepted 27 October 2014; online 31 October 2014)

The crystal structure of the title compound, [ZnCl₂(C₁₅H₁₁N₃)], was redetermined based on modern CCD data. In comparison with the previous determination from photographic film data [Corbridge & Cox (1956 ). J. Chem. Soc. 159, 594–603; Einstein & Penfold (1966 ). Acta Cryst. 20, 924–926], all non-H atoms were refined with anisotropic displacement parameters, leading to a much higher precision in terms of bond lengths and angles [e.g. Zn—Cl = 2.2684 (8) and 2.2883 (11) compared to 2.25 (1) and 2.27 (1) Å]. In the title molecule, the Zn^II atom is five-coordinated in a distorted square-pyramidal mode by two Cl atoms and by the three N atoms from the 2,2′:6′,2′′-terpyridine ligand. The latter is not planar and shows dihedral angles between the least-squares planes of the central pyridine ring and the terminal rings of 3.18 (8) and 6.36 (9)°. The molecules in the crystal structure pack with π–π interactions [centroid–centroid distance = 3.655 (2) Å] between pyridine rings of neighbouring terpyridine moieties. These, together with intermolecular C—H⋯Cl interactions, stablize the three-dimensional structure.

Keywords: crystal structure; redetermination; 2,2′:6′,2′′-terpyridine; zinc complex; π–π interactions.

CCDC reference: 1029855

1. Related literature

The title compound is dimorphic, with one polymorph (form I) crystallizing in space group No. 15, and the second polymorph (type II) crystallizing in space group No. 14 (Corbridge & Cox, 1956). The crystal structure of the title compound was originally determined by Corbridge & Cox (1956) from photographic data (final R value = 0.24) and was later re-refined by Einstein & Penfold (1966) based on the original intensity data but using more advanced least-squares procedures (R = 0.14). In both reports, the setting in P2₁/a of space group No. 14 was used. For background to terpyridine-based materials, see: Fermi et al. (2014 ); Song et al. (2014 ). For the biocompatibility of zinc compounds, see: Gao et al. (2009 ).

2. Experimental

2.1. Crystal data

[ZnCl₂(C₁₅H₁₁N₃)]
M_r = 369.54
Monoclinic, P 2₁ /c
a = 10.950 (5) Å
b = 8.250 (5) Å
c = 16.216 (5) Å
β = 93.911 (5)°
V = 1461.5 (12) Å³
Z = 4
Mo Kα radiation
μ = 2.04 mm⁻¹
T = 298 K
0.30 × 0.20 × 0.20 mm

2.2. Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2002 ) T_min = 0.580, T_max = 0.686
9990 measured reflections
2564 independent reflections
2404 reflections with I > 2σ(I)
R_int = 0.017

2.3. Refinement

R[F² > 2σ(F²)] = 0.020
wR(F²) = 0.056
S = 1.05
2564 reflections
190 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯Cl2ⁱ	0.93	2.68	3.518 (2)	151
C13—H13⋯Cl2ⁱⁱ	0.93	2.81	3.686 (2)	158
Symmetry codes: (i) -x+1, -y+1, -z; (ii) -x, -y, -z.

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); 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) and DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

CCDC reference: 1029855

Crystal structure: contains datablocks I, Global. DOI: 10.1107/S1600536814023605/wm5082sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814023605/wm5082Isup2.hkl

checkCIF report

Related literature top

The title compound is dimorphic, with one polymorph (form I) crystallizing in space group No. 15, and the second polymorph (type II) crystallizing in space group No. 14 (Corbridge & Cox, 1956). The crystal structure of the title compound was originally determined by Corbridge & Cox (1956) from photographic data (final R value = 0.24) and was later re-refined by Einstein & Penfold (1966) based on the original intensity data but using more advanced least-squares procedures (R = 0.14). In both reports, the setting in P2₁/a of space group No. 14 was used. For background to terpyridine-based materials, see: Fermi et al. (2014); Song et al., (2014). For the biocompatibility of zinc compounds, see: Gao et al. (2009).

Experimental top

A solution of 2,2':6',2''-terpyridine (0.23 g, 1 mmol) in acetonitrile (20 ml) was mixed with a solution of zinc chloride (0.14 g, 1 mmol) in methanol (5 ml) and refluxed for 4 h. The reaction mixture was the cooled to room temperature and filtered into a large test tube. Colorless crystals were obtained at room temperature after two weeks. Yield: 75%.

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

The arrangement of the molecules in the crystal structure of (I), showing π—π interactions (dashed red lines) and C—H···Cl hydrogen bonds (dashed green and turquoise lines).

Packing diagram of (I). All H atoms have been omitted for clarity.

Dichlorido(2,2':6',2''-terpyridine-κ³N,N',N'')zinc top

Crystal data top

[ZnCl₂(C₁₅H₁₁N₃)]	F(000) = 744
M_r = 369.54	D_x = 1.679 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 6593 reflections
a = 10.950 (5) Å	θ = 2.8–26.9°
b = 8.250 (5) Å	µ = 2.04 mm⁻¹
c = 16.216 (5) Å	T = 298 K
β = 93.911 (5)°	Block, colorless
V = 1461.5 (12) Å³	0.30 × 0.20 × 0.20 mm
Z = 4

Data collection top

Bruker SMART CCD diffractometer	2564 independent reflections
Radiation source: fine-focus sealed tube	2404 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −13→12
T_min = 0.580, T_max = 0.686	k = −9→9
9990 measured reflections	l = −18→19

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)] = 0.020	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.056	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0322P)² + 0.4083P] where P = (F_o² + 2F_c²)/3
2564 reflections	(Δ/σ)_max < 0.001
190 parameters	Δρ_max = 0.24 e Å⁻³
0 restraints	Δρ_min = −0.24 e Å⁻³

Crystal data top

[ZnCl₂(C₁₅H₁₁N₃)]	V = 1461.5 (12) Å³
M_r = 369.54	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.950 (5) Å	µ = 2.04 mm⁻¹
b = 8.250 (5) Å	T = 298 K
c = 16.216 (5) Å	0.30 × 0.20 × 0.20 mm
β = 93.911 (5)°

Data collection top

Bruker SMART CCD diffractometer	2564 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2002)	2404 reflections with I > 2σ(I)
T_min = 0.580, T_max = 0.686	R_int = 0.017
9990 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.020	0 restraints
wR(F²) = 0.056	H-atom parameters constrained
S = 1.05	Δρ_max = 0.24 e Å⁻³
2564 reflections	Δρ_min = −0.24 e Å⁻³
190 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
Zn1	0.217983 (18)	0.40487 (2)	0.117728 (11)	0.03587 (8)
Cl2	0.33535 (4)	0.17571 (5)	0.13148 (3)	0.04477 (12)
Cl3	0.13940 (5)	0.47642 (7)	0.23837 (3)	0.06000 (15)
N1	0.35875 (14)	0.59791 (17)	0.11822 (9)	0.0384 (3)
N2	0.22895 (12)	0.47354 (16)	−0.00704 (8)	0.0324 (3)
N3	0.05709 (13)	0.29671 (17)	0.05158 (9)	0.0385 (3)
C4	0.48010 (17)	0.7621 (2)	0.03495 (12)	0.0471 (4)
H4	0.5007	0.7944	−0.0173	0.057*
C5	0.39054 (15)	0.6462 (2)	0.04352 (10)	0.0353 (4)
C10	0.15500 (16)	0.40050 (19)	−0.06497 (11)	0.0352 (4)
C9	0.17350 (19)	0.4201 (2)	−0.14845 (11)	0.0462 (5)
H9	0.1228	0.3690	−0.1888	0.055*
C12	−0.03366 (17)	0.2236 (2)	−0.08134 (13)	0.0463 (4)
H12	−0.0337	0.2290	−0.1386	0.056*
C2	0.5060 (2)	0.7802 (2)	0.18111 (14)	0.0564 (5)
H2	0.5441	0.8240	0.2291	0.068*
C8	0.26887 (19)	0.5170 (3)	−0.16981 (11)	0.0497 (5)
H8	0.2832	0.5304	−0.2253	0.060*
C15	−0.02974 (17)	0.2127 (2)	0.08669 (13)	0.0459 (4)
H15	−0.0286	0.2094	0.1441	0.055*
C6	0.32011 (15)	0.56916 (19)	−0.02768 (10)	0.0336 (4)
C11	0.05559 (15)	0.3024 (2)	−0.03164 (11)	0.0369 (4)
C1	0.41594 (19)	0.6650 (2)	0.18517 (12)	0.0485 (5)
H1	0.3938	0.6323	0.2370	0.058*
C14	−0.12109 (18)	0.1307 (2)	0.04107 (15)	0.0522 (5)
H14	−0.1802	0.0728	0.0673	0.063*
C13	−0.12326 (18)	0.1362 (2)	−0.04368 (15)	0.0542 (5)
H13	−0.1841	0.0819	−0.0756	0.065*
C3	0.53854 (19)	0.8291 (3)	0.10520 (14)	0.0560 (5)
H3	0.5994	0.9067	0.1008	0.067*
C7	0.34327 (18)	0.5944 (2)	−0.11007 (11)	0.0430 (4)
H7	0.4068	0.6613	−0.1244	0.052*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.04271 (14)	0.03704 (13)	0.02811 (12)	0.00301 (8)	0.00414 (9)	0.00265 (7)
Cl2	0.0482 (3)	0.0413 (2)	0.0446 (3)	0.00621 (19)	0.00184 (19)	0.00566 (19)
Cl3	0.0765 (4)	0.0645 (3)	0.0410 (3)	0.0083 (3)	0.0181 (2)	−0.0013 (2)
N1	0.0457 (8)	0.0353 (8)	0.0339 (8)	0.0016 (6)	0.0007 (6)	0.0008 (6)
N2	0.0369 (7)	0.0307 (7)	0.0296 (7)	0.0045 (6)	0.0023 (6)	0.0007 (5)
N3	0.0390 (8)	0.0358 (8)	0.0410 (8)	0.0042 (6)	0.0045 (6)	0.0028 (6)
C4	0.0467 (11)	0.0434 (10)	0.0518 (11)	−0.0007 (8)	0.0073 (9)	0.0049 (8)
C5	0.0361 (9)	0.0319 (8)	0.0381 (9)	0.0066 (7)	0.0039 (7)	0.0012 (7)
C10	0.0390 (9)	0.0332 (9)	0.0330 (9)	0.0083 (7)	0.0005 (7)	−0.0021 (7)
C9	0.0546 (11)	0.0507 (11)	0.0328 (10)	0.0051 (9)	−0.0013 (8)	−0.0075 (8)
C12	0.0454 (10)	0.0379 (10)	0.0541 (11)	0.0058 (8)	−0.0071 (8)	−0.0063 (8)
C2	0.0657 (13)	0.0434 (11)	0.0571 (13)	−0.0012 (10)	−0.0170 (10)	−0.0062 (10)
C8	0.0623 (12)	0.0595 (12)	0.0284 (9)	0.0057 (10)	0.0120 (8)	0.0005 (8)
C15	0.0426 (10)	0.0410 (10)	0.0549 (11)	0.0047 (8)	0.0101 (8)	0.0073 (8)
C6	0.0359 (9)	0.0315 (8)	0.0335 (9)	0.0073 (7)	0.0045 (7)	0.0014 (7)
C11	0.0370 (9)	0.0304 (8)	0.0429 (10)	0.0077 (7)	−0.0015 (7)	−0.0017 (7)
C1	0.0646 (12)	0.0426 (11)	0.0370 (10)	0.0025 (9)	−0.0063 (9)	−0.0023 (8)
C14	0.0384 (10)	0.0358 (10)	0.0831 (16)	0.0036 (8)	0.0102 (10)	0.0056 (10)
C13	0.0402 (10)	0.0361 (10)	0.0844 (16)	0.0035 (8)	−0.0091 (10)	−0.0081 (10)
C3	0.0493 (11)	0.0444 (11)	0.0731 (15)	−0.0086 (9)	−0.0050 (10)	−0.0010 (10)
C7	0.0477 (11)	0.0461 (11)	0.0365 (10)	0.0045 (8)	0.0132 (8)	0.0037 (8)

Geometric parameters (Å, º) top

Zn1—N2	2.1123 (14)	C9—H9	0.9300
Zn1—N3	2.1893 (16)	C12—C11	1.386 (3)
Zn1—N1	2.2160 (17)	C12—C13	1.392 (3)
Zn1—Cl3	2.2684 (8)	C12—H12	0.9300
Zn1—Cl2	2.2883 (11)	C2—C3	1.365 (3)
N1—C1	1.336 (2)	C2—C1	1.375 (3)
N1—C5	1.343 (2)	C2—H2	0.9300
N2—C6	1.333 (2)	C8—C7	1.379 (3)
N2—C10	1.341 (2)	C8—H8	0.9300
N3—C15	1.335 (2)	C15—C14	1.380 (3)
N3—C11	1.349 (2)	C15—H15	0.9300
C4—C5	1.383 (3)	C6—C7	1.393 (2)
C4—C3	1.384 (3)	C1—H1	0.9300
C4—H4	0.9300	C14—C13	1.374 (3)
C5—C6	1.487 (2)	C14—H14	0.9300
C10—C9	1.392 (3)	C13—H13	0.9300
C10—C11	1.487 (2)	C3—H3	0.9300
C9—C8	1.378 (3)	C7—H7	0.9300

N2—Zn1—N3	74.72 (6)	C11—C12—H12	120.7
N2—Zn1—N1	74.08 (5)	C13—C12—H12	120.7
N3—Zn1—N1	146.20 (6)	C3—C2—C1	118.67 (19)
N2—Zn1—Cl3	143.70 (4)	C3—C2—H2	120.7
N3—Zn1—Cl3	100.88 (5)	C1—C2—H2	120.7
N1—Zn1—Cl3	96.58 (5)	C7—C8—C9	120.90 (17)
N2—Zn1—Cl2	104.28 (4)	C7—C8—H8	119.5
N3—Zn1—Cl2	97.98 (5)	C9—C8—H8	119.5
N1—Zn1—Cl2	101.98 (6)	N3—C15—C14	122.48 (19)
Cl3—Zn1—Cl2	111.99 (2)	N3—C15—H15	118.8
C1—N1—C5	118.30 (16)	C14—C15—H15	118.8
C1—N1—Zn1	126.03 (13)	N2—C6—C7	121.20 (16)
C5—N1—Zn1	115.64 (11)	N2—C6—C5	114.56 (14)
C6—N2—C10	121.12 (14)	C7—C6—C5	124.22 (16)
C6—N2—Zn1	119.46 (11)	N3—C11—C12	121.68 (17)
C10—N2—Zn1	118.66 (11)	N3—C11—C10	115.04 (15)
C15—N3—C11	118.97 (16)	C12—C11—C10	123.27 (17)
C15—N3—Zn1	125.12 (13)	N1—C1—C2	123.08 (19)
C11—N3—Zn1	115.48 (11)	N1—C1—H1	118.5
C5—C4—C3	119.01 (18)	C2—C1—H1	118.5
C5—C4—H4	120.5	C13—C14—C15	118.87 (19)
C3—C4—H4	120.5	C13—C14—H14	120.6
N1—C5—C4	121.64 (17)	C15—C14—H14	120.6
N1—C5—C6	114.90 (15)	C14—C13—C12	119.42 (19)
C4—C5—C6	123.44 (16)	C14—C13—H13	120.3
N2—C10—C9	120.56 (17)	C12—C13—H13	120.3
N2—C10—C11	114.32 (15)	C2—C3—C4	119.32 (19)
C9—C10—C11	125.12 (16)	C2—C3—H3	120.3
C8—C9—C10	118.35 (18)	C4—C3—H3	120.3
C8—C9—H9	120.8	C8—C7—C6	117.84 (17)
C10—C9—H9	120.8	C8—C7—H7	121.1
C11—C12—C13	118.6 (2)	C6—C7—H7	121.1

N2—Zn1—N1—C1	174.74 (16)	N2—C10—C9—C8	−0.5 (3)
N3—Zn1—N1—C1	151.48 (14)	C11—C10—C9—C8	179.05 (16)
Cl3—Zn1—N1—C1	30.57 (15)	C10—C9—C8—C7	−0.8 (3)
Cl2—Zn1—N1—C1	−83.62 (15)	C11—N3—C15—C14	0.2 (3)
N2—Zn1—N1—C5	−7.44 (11)	Zn1—N3—C15—C14	−171.91 (14)
N3—Zn1—N1—C5	−30.69 (17)	C10—N2—C6—C7	−1.2 (2)
Cl3—Zn1—N1—C5	−151.60 (11)	Zn1—N2—C6—C7	168.70 (12)
Cl2—Zn1—N1—C5	94.20 (11)	C10—N2—C6—C5	177.68 (14)
N3—Zn1—N2—C6	177.72 (13)	Zn1—N2—C6—C5	−12.46 (18)
N1—Zn1—N2—C6	10.88 (11)	N1—C5—C6—N2	5.3 (2)
Cl3—Zn1—N2—C6	90.10 (13)	C4—C5—C6—N2	−173.10 (16)
Cl2—Zn1—N2—C6	−87.75 (12)	N1—C5—C6—C7	−175.93 (16)
N3—Zn1—N2—C10	−12.17 (11)	C4—C5—C6—C7	5.7 (3)
N1—Zn1—N2—C10	−179.01 (13)	C15—N3—C11—C12	0.0 (2)
Cl3—Zn1—N2—C10	−99.79 (13)	Zn1—N3—C11—C12	172.94 (13)
Cl2—Zn1—N2—C10	82.36 (12)	C15—N3—C11—C10	179.28 (14)
N2—Zn1—N3—C15	−177.15 (15)	Zn1—N3—C11—C10	−7.83 (18)
N1—Zn1—N3—C15	−153.97 (13)	C13—C12—C11—N3	−0.2 (3)
Cl3—Zn1—N3—C15	−34.18 (14)	C13—C12—C11—C10	−179.42 (16)
Cl2—Zn1—N3—C15	80.15 (14)	N2—C10—C11—N3	−2.3 (2)
N2—Zn1—N3—C11	10.46 (11)	C9—C10—C11—N3	178.21 (16)
N1—Zn1—N3—C11	33.64 (17)	N2—C10—C11—C12	176.96 (15)
Cl3—Zn1—N3—C11	153.42 (11)	C9—C10—C11—C12	−2.6 (3)
Cl2—Zn1—N3—C11	−92.24 (11)	C5—N1—C1—C2	−0.4 (3)
C1—N1—C5—C4	0.1 (2)	Zn1—N1—C1—C2	177.41 (15)
Zn1—N1—C5—C4	−177.91 (13)	C3—C2—C1—N1	0.2 (3)
C1—N1—C5—C6	−178.31 (15)	N3—C15—C14—C13	−0.3 (3)
Zn1—N1—C5—C6	3.69 (18)	C15—C14—C13—C12	0.1 (3)
C3—C4—C5—N1	0.3 (3)	C11—C12—C13—C14	0.2 (3)
C3—C4—C5—C6	178.53 (17)	C1—C2—C3—C4	0.1 (3)
C6—N2—C10—C9	1.4 (2)	C5—C4—C3—C2	−0.4 (3)
Zn1—N2—C10—C9	−168.50 (13)	C9—C8—C7—C6	1.1 (3)
C6—N2—C10—C11	−178.11 (14)	N2—C6—C7—C8	−0.1 (3)
Zn1—N2—C10—C11	11.94 (18)	C5—C6—C7—C8	−178.83 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···Cl2ⁱ	0.93	2.68	3.518 (2)	151
C13—H13···Cl2ⁱⁱ	0.93	2.81	3.686 (2)	158

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···Cl2ⁱ	0.93	2.68	3.518 (2)	150.7
C13—H13···Cl2ⁱⁱ	0.93	2.81	3.686 (2)	158.2

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

Acknowledgements

This work was supported by the National Natural Science Foundation of China (51372003), Anhui Provincial Natural Science Foundation (1308085MB24) and the Educational Commission of Anhui Province of China (KJ2012A025).

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