4,4′-(Cyclo­hexane-1,1-di­yl)dianilinium dichloride monohydrate

Qian, H.-F.; Huang, W.

doi:10.1107/S1600536811032995

organic compounds

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Volume 67| Part 9| September 2011| Page o2420

doi:10.1107/S1600536811032995

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4,4′-(Cyclohexane-1,1-diyl)dianilinium dichloride monohydrate

Hui-Fen Qian ^a ^* and Wei Huang ^b

^aCollege of Sciences, Nanjing University of Technology, Nanjing 210009, People's Republic of China, and ^bState Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China
^*Correspondence e-mail: qhf@njut.edu.cn

(Received 15 July 2011; accepted 15 August 2011; online 27 August 2011)

In the title compound, C₁₈H₂₄N₂²⁺·2Cl⁻·H₂O, both the cation and the water molecule lie on a twofold crystallographic axis. In the cation, the two benzene rings are perpendicular to each other, making a symmetry-constrained dihedral angle of 90°. In the crystal, N—H⋯Cl, O—H⋯Cl and N—H⋯O hydrogen bonds result in the formation of a three-dimensional network.

Related literature

For related structures, see: Hanton et al. (1992 ); Qian & Huang (2010 ).

Experimental

Crystal data

C₁₈H₂₄N₂²⁺·2Cl⁻·H₂O
M_r = 357.31
Monoclinic, P 2₁ /m
a = 8.442 (3) Å
b = 9.548 (4) Å
c = 12.098 (5) Å
β = 107.085 (5)°
V = 932.1 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.35 mm⁻¹
T = 291 K
0.12 × 0.12 × 0.10 mm

Data collection

Bruker 1K CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.959, T_max = 0.965
4705 measured reflections
1735 independent reflections
1158 reflections with I > 2σ(I)
R_int = 0.102

Refinement

R[F² > 2σ(F²)] = 0.065
wR(F²) = 0.212
S = 1.10
1735 reflections
126 parameters
H-atom parameters constrained
Δρ_max = 0.74 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2C⋯Cl1ⁱ	0.89	2.70	3.253 (3)	121
N2—H2C⋯Cl1ⁱⁱ	0.89	2.53	3.252 (3)	139
N2—H2B⋯Cl1ⁱⁱⁱ	0.89	2.41	3.253 (3)	159
N2—H2A⋯Cl1^iv	0.89	2.46	3.252 (3)	148
O1—H1E⋯Cl1^v	0.85	2.42	3.183 (3)	150
O1—H1D⋯Cl1^vi	0.82	2.38	3.183 (3)	167
N1—H1C⋯Cl1^vii	0.90	2.22	3.101 (3)	165
N1—H1B⋯O1^viii	0.90	1.78	2.678 (6)	172
N1—H1A⋯Cl1^ix	0.90	2.23	3.101 (3)	163
Symmetry codes: (i) $[x+1, -y+{\script{3\over 2}}, z]$ ; (ii) $[-x+2, y-{\script{1\over 2}}, -z+1]$ ; (iii) x+1, y-1, z; (iv) -x+2, -y+1, -z+1; (v) -x+1, -y+1, -z+1; (vi) $[-x+1, y-{\script{1\over 2}}, -z+1]$ ; (vii) x+1, y-1, z-1; (viii) x, y, z-1; (ix) $[x+1, -y+{\script{3\over 2}}, z-1]$ .

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811032995/ff2022sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811032995/ff2022Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811032995/ff2022Isup3.cml

checkCIF report

Comment top

There have been only one related single-crystal structural report on 1,1-bis(4-amino-3,5-dimethylphenyl)cyclohexane (Hanton et al., 1992). We have previously reported the single-crystal structure of a similar compound biphenyl-3,3',4,4'-tetraamine (Qian & Huang, 2010). In this work, we describe the single-crystal structure of hydrochloride salt of 1,1-bis(4-aminophenyl)cyclohexane.

The atom-numbering scheme of the title compound is shown in Fig. 1, while selected bond distances and bond angles are given in Table 1. The two phenyl rings of the title compound are perpendicular to each other with a dihedral angle of 90°. In the crystal packing, N—H···Cl and O—H···Cl hydrogen-bond interactions give rise to a three-dimensional network.

Related literature top

For related structures, see: Hanton et al. (1992); Qian & Huang (2010).

Experimental top

The treatment of 1,1-bis(4-aminophenyl)cyclohexane dissolved in methanol with an excess of hydrochloric acid yields the title compound. Single crystals suitable for X-ray diffraction measurement were obtained after 7 days' slow evaporation of the mother liquid at room temperature in air. Anal. Calcd. For C₁₈H₂₄N₂²⁺.2Cl^-.H₂O: C, 60.50; H, 7.33; N, 7.84%. Found: C, 60.31; H, 7.55; N, 7.96%.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. An ORTEP drawing of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry codes: (A) x, 0.5-y, z]

4,4'-(Cyclohexane-1,1-diyl)dianilinium dichloride monohydrate top

Crystal data top

C₁₈H₂₄N₂²⁺·2Cl⁻·H₂O	F(000) = 380
M_r = 357.31	D_x = 1.273 Mg m⁻³
Monoclinic, P2₁/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 1254 reflections
a = 8.442 (3) Å	θ = 2.5–24.5°
b = 9.548 (4) Å	µ = 0.35 mm⁻¹
c = 12.098 (5) Å	T = 291 K
β = 107.085 (5)°	Block, colourless
V = 932.1 (6) Å³	0.12 × 0.12 × 0.10 mm
Z = 2

Data collection top

Bruker 1K CCD area-detector diffractometer	1735 independent reflections
Radiation source: fine-focus sealed tube	1158 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.102
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −8→10
T_min = 0.959, T_max = 0.965	k = −11→10
4705 measured reflections	l = −14→13

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)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.212	H-atom parameters constrained
S = 1.10	w = 1/[σ²(F_o²) + (0.1167P)²] where P = (F_o² + 2F_c²)/3
1735 reflections	(Δ/σ)_max < 0.001
126 parameters	Δρ_max = 0.74 e Å⁻³
0 restraints	Δρ_min = −0.51 e Å⁻³

Crystal data top

C₁₈H₂₄N₂²⁺·2Cl⁻·H₂O	V = 932.1 (6) Å³
M_r = 357.31	Z = 2
Monoclinic, P2₁/m	Mo Kα radiation
a = 8.442 (3) Å	µ = 0.35 mm⁻¹
b = 9.548 (4) Å	T = 291 K
c = 12.098 (5) Å	0.12 × 0.12 × 0.10 mm
β = 107.085 (5)°

Data collection top

Bruker 1K CCD area-detector diffractometer	1735 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2000)	1158 reflections with I > 2σ(I)
T_min = 0.959, T_max = 0.965	R_int = 0.102
4705 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.065	0 restraints
wR(F²) = 0.212	H-atom parameters constrained
S = 1.10	Δρ_max = 0.74 e Å⁻³
1735 reflections	Δρ_min = −0.51 e Å⁻³
126 parameters

Special details top

Experimental. The structure was solved by direct methods (Bruker, 2000) and successive difference Fourier syntheses.

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	Occ. (<1)
C1	0.9232 (4)	0.2500	−0.0868 (3)	0.0294 (9)
C2	1.0908 (5)	0.2500	−0.0779 (3)	0.0359 (9)
H2	1.1675	0.2500	−0.0048	0.043*
C3	1.1484 (5)	0.2500	−0.1747 (4)	0.0417 (10)
H3	1.2616	0.2500	−0.1659	0.050*
C4	1.0383 (5)	0.2500	−0.2816 (3)	0.0386 (10)
C5	0.8702 (5)	0.2500	−0.2956 (3)	0.0425 (10)
H5	0.7954	0.2500	−0.3694	0.051*
C6	0.8136 (5)	0.2500	−0.1994 (3)	0.0372 (10)
H6	0.7000	0.2500	−0.2095	0.045*
C7	0.8564 (4)	0.2500	0.0183 (3)	0.0319 (9)
C8	0.7457 (3)	0.1189 (3)	0.0130 (2)	0.0424 (8)
H8A	0.6611	0.1165	−0.0613	0.051*
H8B	0.8131	0.0354	0.0190	0.051*
C9	0.6634 (4)	0.1176 (4)	0.1081 (3)	0.0613 (11)
H9A	0.7474	0.1105	0.1824	0.074*
H9B	0.5920	0.0362	0.0991	0.074*
C10	0.5613 (6)	0.2500	0.1054 (4)	0.077 (2)
H10A	0.4679	0.2500	0.0358	0.092*
H10B	0.5181	0.2500	0.1713	0.092*
C11	1.0029 (4)	0.2500	0.1307 (3)	0.0305 (9)
C12	1.0744 (3)	0.1265 (3)	0.1817 (2)	0.0403 (8)
H12	1.0283	0.0417	0.1503	0.048*
C13	1.2123 (4)	0.1256 (3)	0.2777 (2)	0.0436 (8)
H13	1.2590	0.0414	0.3101	0.052*
C14	1.2789 (5)	0.2500	0.3243 (3)	0.0362 (10)
Cl1	0.35794 (16)	1.02159 (14)	0.60558 (11)	0.1036 (6)
N1	1.1019 (5)	0.2500	−0.3833 (3)	0.0507 (10)
H1A	1.1617	0.3283	−0.3818	0.061*	0.50
H1B	1.0163	0.2500	−0.4484	0.061*
H1C	1.1641	0.1729	−0.3814	0.061*	0.50
N2	1.4267 (4)	0.2500	0.4255 (3)	0.0493 (10)
H2A	1.5082	0.2037	0.4086	0.059*	0.50
H2B	1.4031	0.2084	0.4846	0.059*	0.50
H2C	1.4584	0.3378	0.4446	0.059*	0.50
O1	0.8669 (6)	0.2500	0.4122 (4)	0.128 (2)
H1D	0.8043	0.3178	0.3960	0.192*	0.50
H1E	0.7860	0.1950	0.3841	0.192*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.030 (2)	0.025 (2)	0.032 (2)	0.000	0.0082 (15)	0.000
C2	0.030 (2)	0.039 (2)	0.039 (2)	0.000	0.0105 (16)	0.000
C3	0.035 (2)	0.046 (3)	0.048 (2)	0.000	0.0184 (19)	0.000
C4	0.041 (2)	0.041 (2)	0.041 (2)	0.000	0.0226 (19)	0.000
C5	0.044 (2)	0.046 (3)	0.036 (2)	0.000	0.0099 (18)	0.000
C6	0.028 (2)	0.043 (2)	0.041 (2)	0.000	0.0109 (17)	0.000
C7	0.0252 (19)	0.036 (2)	0.033 (2)	0.000	0.0060 (15)	0.000
C8	0.0352 (16)	0.054 (2)	0.0357 (15)	−0.0139 (14)	0.0078 (12)	0.0014 (13)
C9	0.0405 (18)	0.099 (3)	0.0450 (18)	−0.0282 (19)	0.0127 (14)	0.0056 (18)
C10	0.035 (3)	0.155 (6)	0.045 (3)	0.000	0.018 (2)	0.000
C11	0.0286 (19)	0.035 (2)	0.0291 (19)	0.000	0.0101 (15)	0.000
C12	0.0418 (17)	0.0318 (16)	0.0425 (16)	0.0008 (13)	0.0051 (13)	−0.0019 (12)
C13	0.0439 (17)	0.0334 (17)	0.0456 (17)	0.0044 (13)	0.0007 (13)	0.0073 (13)
C14	0.030 (2)	0.043 (2)	0.033 (2)	0.000	0.0056 (17)	0.000
Cl1	0.1165 (11)	0.1117 (11)	0.1092 (10)	0.0666 (8)	0.0747 (8)	0.0572 (7)
N1	0.053 (2)	0.057 (3)	0.050 (2)	0.000	0.0262 (18)	0.000
N2	0.041 (2)	0.058 (3)	0.039 (2)	0.000	−0.0023 (15)	0.000
O1	0.106 (4)	0.199 (7)	0.067 (3)	0.000	0.007 (3)	0.000

Geometric parameters (Å, º) top

C1—C2	1.388 (5)	C9—H9B	0.9700
C1—C6	1.404 (5)	C10—C9ⁱ	1.525 (5)
C1—C7	1.535 (5)	C10—H10A	0.9700
C2—C3	1.393 (5)	C10—H10B	0.9700
C2—H2	0.9300	C11—C12ⁱ	1.384 (3)
C3—C4	1.352 (6)	C11—C12	1.384 (3)
C3—H3	0.9300	C12—C13	1.383 (4)
C4—C5	1.379 (6)	C12—H12	0.9300
C4—N1	1.480 (5)	C13—C14	1.363 (3)
C5—C6	1.382 (5)	C13—H13	0.9300
C5—H5	0.9300	C14—C13ⁱ	1.363 (3)
C6—H6	0.9300	C14—N2	1.469 (5)
C7—C11	1.546 (5)	N1—H1A	0.8993
C7—C8	1.552 (4)	N1—H1B	0.8990
C7—C8ⁱ	1.552 (4)	N1—H1C	0.9005
C8—C9	1.508 (4)	N2—H2A	0.8900
C8—H8A	0.9700	N2—H2B	0.8900
C8—H8B	0.9700	N2—H2C	0.8900
C9—C10	1.525 (5)	O1—H1D	0.8217
C9—H9A	0.9700	O1—H1E	0.8491

C2—C1—C6	116.2 (3)	C10—C9—H9B	109.4
C2—C1—C7	123.4 (3)	H9A—C9—H9B	108.0
C6—C1—C7	120.4 (3)	C9ⁱ—C10—C9	112.0 (4)
C1—C2—C3	122.3 (4)	C9ⁱ—C10—H10A	109.2
C1—C2—H2	118.9	C9—C10—H10A	109.2
C3—C2—H2	118.9	C9ⁱ—C10—H10B	109.2
C4—C3—C2	119.5 (4)	C9—C10—H10B	109.2
C4—C3—H3	120.3	H10A—C10—H10B	107.9
C2—C3—H3	120.3	C12ⁱ—C11—C12	116.8 (3)
C3—C4—C5	120.7 (4)	C12ⁱ—C11—C7	121.54 (17)
C3—C4—N1	118.7 (3)	C12—C11—C7	121.54 (17)
C5—C4—N1	120.6 (4)	C13—C12—C11	121.9 (3)
C4—C5—C6	119.7 (4)	C13—C12—H12	119.0
C4—C5—H5	120.2	C11—C12—H12	119.0
C6—C5—H5	120.2	C14—C13—C12	119.0 (3)
C5—C6—C1	121.6 (4)	C14—C13—H13	120.5
C5—C6—H6	119.2	C12—C13—H13	120.5
C1—C6—H6	119.2	C13—C14—C13ⁱ	121.2 (3)
C1—C7—C11	109.6 (3)	C13—C14—N2	119.38 (18)
C1—C7—C8	109.2 (2)	C13ⁱ—C14—N2	119.38 (18)
C11—C7—C8	110.63 (19)	C4—N1—H1A	108.8
C1—C7—C8ⁱ	109.2 (2)	C4—N1—H1B	109.5
C11—C7—C8ⁱ	110.63 (19)	H1A—N1—H1B	108.6
C8—C7—C8ⁱ	107.5 (3)	C4—N1—H1C	109.3
C9—C8—C7	112.4 (3)	H1A—N1—H1C	111.0
C9—C8—H8A	109.1	H1B—N1—H1C	109.6
C7—C8—H8A	109.1	C14—N2—H2A	109.5
C9—C8—H8B	109.1	C14—N2—H2B	109.5
C7—C8—H8B	109.1	H2A—N2—H2B	109.5
H8A—C8—H8B	107.8	C14—N2—H2C	109.5
C8—C9—C10	111.2 (3)	H2A—N2—H2C	109.5
C8—C9—H9A	109.4	H2B—N2—H2C	109.5
C10—C9—H9A	109.4	H1D—O1—H1E	90.4
C8—C9—H9B	109.4

C6—C1—C2—C3	0.0	C1—C7—C8—C9	−175.1 (2)
C7—C1—C2—C3	180.0	C11—C7—C8—C9	64.2 (3)
C1—C2—C3—C4	0.0	C8ⁱ—C7—C8—C9	−56.7 (4)
C2—C3—C4—C5	0.0	C7—C8—C9—C10	56.5 (3)
C2—C3—C4—N1	180.0	C8—C9—C10—C9ⁱ	−53.9 (5)
C3—C4—C5—C6	0.0	C1—C7—C11—C12ⁱ	88.2 (3)
N1—C4—C5—C6	180.0	C8—C7—C11—C12ⁱ	−151.3 (3)
C4—C5—C6—C1	0.0	C8ⁱ—C7—C11—C12ⁱ	−32.3 (4)
C2—C1—C6—C5	0.0	C1—C7—C11—C12	−88.2 (3)
C7—C1—C6—C5	180.0	C8—C7—C11—C12	32.3 (4)
C2—C1—C7—C11	0.0	C8ⁱ—C7—C11—C12	151.3 (3)
C6—C1—C7—C11	180.0	C12ⁱ—C11—C12—C13	−1.0 (5)
C2—C1—C7—C8	−121.3 (2)	C7—C11—C12—C13	175.6 (3)
C6—C1—C7—C8	58.7 (2)	C11—C12—C13—C14	0.6 (5)
C2—C1—C7—C8ⁱ	121.3 (2)	C12—C13—C14—C13ⁱ	−0.2 (6)
C6—C1—C7—C8ⁱ	−58.7 (2)	C12—C13—C14—N2	−179.2 (3)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2C···Cl1ⁱⁱ	0.89	2.70	3.253 (3)	121
N2—H2C···Cl1ⁱⁱⁱ	0.89	2.53	3.252 (3)	139
N2—H2B···Cl1^iv	0.89	2.41	3.253 (3)	159
N2—H2A···Cl1^v	0.89	2.46	3.252 (3)	148
O1—H1E···Cl1^vi	0.85	2.42	3.183 (3)	150
O1—H1D···Cl1^vii	0.82	2.38	3.183 (3)	167
N1—H1C···Cl1^viii	0.90	2.22	3.101 (3)	165
N1—H1B···O1^ix	0.90	1.78	2.678 (6)	172
N1—H1A···Cl1^x	0.90	2.23	3.101 (3)	163

Symmetry codes: (ii) x+1, −y+3/2, z; (iii) −x+2, y−1/2, −z+1; (iv) x+1, y−1, z; (v) −x+2, −y+1, −z+1; (vi) −x+1, −y+1, −z+1; (vii) −x+1, y−1/2, −z+1; (viii) x+1, y−1, z−1; (ix) x, y, z−1; (x) x+1, −y+3/2, z−1.

Experimental details

Crystal data
Chemical formula	C₁₈H₂₄N₂²⁺·2Cl⁻·H₂O
M_r	357.31
Crystal system, space group	Monoclinic, P2₁/m
Temperature (K)	291
a, b, c (Å)	8.442 (3), 9.548 (4), 12.098 (5)
β (°)	107.085 (5)
V (Å³)	932.1 (6)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.35
Crystal size (mm)	0.12 × 0.12 × 0.10

Data collection
Diffractometer	Bruker 1K CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.959, 0.965
No. of measured, independent and observed [I > 2σ(I)] reflections	4705, 1735, 1158
R_int	0.102
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.065, 0.212, 1.10
No. of reflections	1735
No. of parameters	126
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.74, −0.51

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2C···Cl1ⁱ	0.89	2.70	3.253 (3)	121.4
N2—H2C···Cl1ⁱⁱ	0.89	2.53	3.252 (3)	138.6
N2—H2B···Cl1ⁱⁱⁱ	0.89	2.41	3.253 (3)	158.7
N2—H2A···Cl1^iv	0.89	2.46	3.252 (3)	148.4
O1—H1E···Cl1^v	0.85	2.42	3.183 (3)	149.8
O1—H1D···Cl1^vi	0.82	2.38	3.183 (3)	167.2
N1—H1C···Cl1^vii	0.90	2.22	3.101 (3)	164.9
N1—H1B···O1^viii	0.90	1.78	2.678 (6)	172.3
N1—H1A···Cl1^ix	0.90	2.23	3.101 (3)	163.2

Symmetry codes: (i) x+1, −y+3/2, z; (ii) −x+2, y−1/2, −z+1; (iii) x+1, y−1, z; (iv) −x+2, −y+1, −z+1; (v) −x+1, −y+1, −z+1; (vi) −x+1, y−1/2, −z+1; (vii) x+1, y−1, z−1; (viii) x, y, z−1; (ix) x+1, −y+3/2, z−1.

Acknowledgements

We would like to acknowledge the National Natural Science Foundation of China (No. 20871065) and the Jiangsu Province Department of Science and Technology (No. BK2009226) for financial aid.

References

Bruker (2000). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Hanton, L. R., Hunter, C. A. & Purvis, D. H. (1992). Chem. Commun. pp. 1134–1136. Google Scholar
Qian, H.-F. & Huang, W. (2010). Acta Cryst. E66, o1060. CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar