cis-[(7R,14R)-5,5,7,12,12,14-Hexa­methyl-1,4,8,11-tetra­azacyclo­tetra­decane-κ4N](oxalato-κ2O,O′)nickel(II) oxalic acid solvate

Ou, G.-C.; Dai, Y.-Q.; Tang, M.-S.

doi:10.1107/S1600536809020042

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 7| July 2009| Page m723

doi:10.1107/S1600536809020042

Open

access

cis-[(7R,14R)-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-κ⁴N](oxalato-κ²O,O′)nickel(II) oxalic acid solvate

Guang-Chuan Ou,^a ^* Yong-Qiang Dai ^a and Man-Sheng Tang ^a

^aDepartment of Biology and Chemistry, Hunan University of Science and Engineering, Yongzhou Hunan 425100, People's Republic of China
^*Correspondence e-mail: ouguangchuan@yahoo.com.cn

(Received 14 May 2009; accepted 26 May 2009; online 6 June 2009)

Both molecules of the title compound, [Ni(C₂O₄)(C₁₆H₃₆N₄)]·C₂H₂O₄, are located on a crystallographic twofold rotation axis. The Ni^II atom shows a distorted octahedral geometry. The crystal packing is stabilized by N—H⋯O and O—H⋯O hydrogen bonds.

Related literature

For general background, see: Tait & Busch (1976 ); Curtis (1965 ). For a related crystal structure, see: Tang et al. (2002 ).

Experimental

Crystal data

[Ni(C₂O₄)(C₁₆H₃₆N₄)]·C₂H₂O₄
M_r = 521.25
Orthorhombic, P 2₁ 2₁ 2
a = 10.1261 (15) Å
b = 15.515 (2) Å
c = 8.0467 (11) Å
V = 1264.2 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.82 mm⁻¹
T = 173 K
0.48 × 0.21 × 0.15 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.695, T_max = 0.887
5665 measured reflections
2740 independent reflections
2435 reflections with I > 2σ(I)
R_int = 0.022

Refinement

R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.064
S = 1.08
2740 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 0.40 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ), 1131 Friedel pairs
Flack parameter: 0.027 (13)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1C⋯O4ⁱ	0.93	2.17	3.075 (2)	164
N2—H2C⋯O2ⁱⁱ	0.93	2.13	2.987 (2)	152
O3—H3A⋯O2ⁱⁱⁱ	0.84	1.70	2.532 (2)	170
Symmetry codes: (i) x, y-1, z; (ii) x, y, z+1; (iii) -x+2, -y+1, z.

Data collection: SMART (Bruker, 1997 ); cell refinement: SAINT (Bruker, 1997); 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/S1600536809020042/bt2961sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809020042/bt2961Isup2.hkl

checkCIF report

Comment top

Recently, many helical structures have been constructed through the coordination interactions of the organic ligand with suitable metal ions. Helical polymers constructed via hydrogen bonding, which is a versatile and efficient strategy, are still rare, and only a few cases have been reported. Then we employ chiral macrocyclic ligand L and oxalic acid as building blocks to construct helical structure, and unfortunately the helical structure is not obtained.

As illustrated in Fig.1, the six-coordinated Ni centre displays a distorted octahedral geometry. Neighbouring molecules are connected through intermolecular N-H···O and O-H···O hydrogen bonds (Fig. 2).

Related literature top

For general background, see: Tait et al. (1976); Curtis (1965). For a related crystal structure, see: Tang et al. (2002).

Experimental top

Oxalic acid (0.5 g, 4 mmol) and NaOH (0.08 g, 2 mmol) were dissolved in 15 ml of water. To this solution was added [Ni(C₁₆H₃₆N₄)](ClO₄)₂ (0.54 g, 1 mmol) dissolved in 2 ml of CH₃CN. The solution was left to stand at room temperature and violet crystals formed after several weeks.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); 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, showing displacement ellipsoids at the 50% probability level; symmetry codes for the generated atoms: A(1 - x, 2 - y, z), B(2 - x, -y, z). H-atoms have been excluded for clarity.
	Fig. 2. The hydrogen bond pattern in the title compound.

cis-[(7R,14R)-5,5,7,12,12,14-Hexamethyl-1,4,8,11- tetraazacyclotetradecane-κ⁴N](oxalato- κ²O,O')nickel(II) oxalic acid solvate top

Crystal data top

[Ni(C₂O₄)(C₁₆H₃₆N₄)]·C₂H₂O₄	F(000) = 556
M_r = 521.25	D_x = 1.369 Mg m⁻³
Orthorhombic, P2₁2₁2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 3630 reflections
a = 10.1261 (15) Å	θ = 2.4–26.9°
b = 15.515 (2) Å	µ = 0.82 mm⁻¹
c = 8.0467 (11) Å	T = 173 K
V = 1264.2 (3) Å³	Prism, violet
Z = 2	0.48 × 0.21 × 0.15 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	2740 independent reflections
Radiation source: fine-focus sealed tube	2435 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
ϕ and ω scans	θ_max = 27.1°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→12
T_min = 0.695, T_max = 0.887	k = −19→8
5665 measured reflections	l = −10→8

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.064	w = 1/[σ²(F_o²) + (0.0267P)²] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.001
2740 reflections	Δρ_max = 0.40 e Å⁻³
154 parameters	Δρ_min = −0.19 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1131 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.027 (13)

Crystal data top

[Ni(C₂O₄)(C₁₆H₃₆N₄)]·C₂H₂O₄	V = 1264.2 (3) Å³
M_r = 521.25	Z = 2
Orthorhombic, P2₁2₁2	Mo Kα radiation
a = 10.1261 (15) Å	µ = 0.82 mm⁻¹
b = 15.515 (2) Å	T = 173 K
c = 8.0467 (11) Å	0.48 × 0.21 × 0.15 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	2740 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2435 reflections with I > 2σ(I)
T_min = 0.695, T_max = 0.887	R_int = 0.022
5665 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.064	Δρ_max = 0.40 e Å⁻³
S = 1.08	Δρ_min = −0.19 e Å⁻³
2740 reflections	Absolute structure: Flack (1983), 1131 Friedel pairs
154 parameters	Absolute structure parameter: 0.027 (13)
0 restraints

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
Ni1	1.0000	0.0000	0.60729 (3)	0.02079 (9)
C10	0.57461 (18)	1.00225 (19)	0.2451 (2)	0.0304 (4)
O1	1.09484 (13)	0.05954 (8)	0.40383 (17)	0.0245 (3)
N1	0.81963 (17)	0.07108 (10)	0.6220 (2)	0.0256 (4)
H1C	0.7759	0.0597	0.5227	0.031*
C3	1.0605 (3)	0.17864 (15)	0.7602 (3)	0.0338 (6)
H3	1.0887	0.1991	0.6478	0.041*
C5	0.9146 (3)	0.19508 (15)	0.7775 (3)	0.0366 (6)
H5A	0.9025	0.2577	0.7950	0.044*
H5B	0.8846	0.1659	0.8801	0.044*
N2	1.09305 (18)	0.08487 (10)	0.7733 (2)	0.0271 (4)
H2C	1.0718	0.0672	0.8804	0.032*
O2	1.12362 (14)	0.03860 (10)	0.13153 (16)	0.0360 (4)
O3	0.62920 (15)	0.94107 (11)	0.1583 (2)	0.0423 (4)
H3A	0.7117	0.9467	0.1609	0.064*
O4	0.63195 (17)	1.05745 (11)	0.3227 (2)	0.0520 (5)
C2	1.2350 (2)	0.06808 (14)	0.7481 (3)	0.0331 (5)
H2A	1.2869	0.0964	0.8369	0.040*
H2B	1.2636	0.0920	0.6399	0.040*
C9	1.0624 (2)	0.02855 (12)	0.2656 (2)	0.0249 (4)
C1	0.7410 (2)	0.02740 (14)	0.7515 (3)	0.0334 (5)
H1A	0.6460	0.0390	0.7329	0.040*
H1B	0.7652	0.0505	0.8620	0.040*
C6	0.8215 (2)	0.16770 (13)	0.6365 (2)	0.0301 (5)
C4	1.1353 (3)	0.23189 (14)	0.8912 (3)	0.0486 (7)
H4A	1.1131	0.2930	0.8782	0.073*
H4B	1.2306	0.2240	0.8764	0.073*
H4C	1.1097	0.2126	1.0027	0.073*
C8	0.6827 (3)	0.20270 (16)	0.6697 (3)	0.0452 (6)
H8A	0.6209	0.1782	0.5888	0.068*
H8B	0.6833	0.2656	0.6594	0.068*
H8C	0.6551	0.1866	0.7823	0.068*
C7	0.8682 (2)	0.20360 (14)	0.4693 (3)	0.0343 (5)
H7A	0.9557	0.1803	0.4432	0.051*
H7B	0.8731	0.2666	0.4756	0.051*
H7C	0.8057	0.1869	0.3821	0.051*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.02928 (17)	0.02073 (15)	0.01236 (14)	−0.00015 (18)	0.000	0.000
C10	0.0352 (10)	0.0320 (10)	0.0240 (9)	−0.0018 (13)	−0.0030 (8)	0.0069 (14)
O1	0.0311 (7)	0.0263 (7)	0.0160 (7)	0.0006 (6)	−0.0020 (6)	0.0021 (6)
N1	0.0341 (9)	0.0269 (8)	0.0159 (8)	0.0017 (7)	0.0010 (8)	−0.0023 (7)
C3	0.0562 (15)	0.0247 (11)	0.0205 (11)	−0.0054 (11)	−0.0064 (11)	−0.0006 (9)
C5	0.0602 (18)	0.0221 (11)	0.0277 (13)	0.0046 (11)	−0.0021 (12)	−0.0058 (10)
N2	0.0421 (11)	0.0249 (9)	0.0142 (8)	−0.0023 (8)	−0.0032 (7)	0.0006 (7)
O2	0.0294 (8)	0.0628 (10)	0.0158 (7)	−0.0010 (7)	0.0028 (6)	0.0070 (7)
O3	0.0281 (8)	0.0581 (11)	0.0408 (9)	−0.0047 (8)	0.0026 (7)	−0.0161 (8)
O4	0.0439 (10)	0.0474 (10)	0.0647 (12)	0.0033 (8)	−0.0190 (9)	−0.0187 (9)
C2	0.0385 (13)	0.0368 (13)	0.0239 (11)	−0.0086 (11)	−0.0034 (10)	−0.0029 (10)
C9	0.0278 (10)	0.0297 (10)	0.0170 (9)	0.0073 (8)	−0.0008 (8)	0.0048 (8)
C1	0.0356 (12)	0.0391 (13)	0.0255 (11)	0.0041 (10)	0.0104 (10)	−0.0003 (9)
C6	0.0404 (13)	0.0262 (10)	0.0238 (11)	0.0077 (9)	−0.0002 (10)	−0.0034 (9)
C4	0.0816 (19)	0.0296 (11)	0.0346 (13)	−0.0077 (12)	−0.0185 (15)	−0.0059 (12)
C8	0.0556 (16)	0.0412 (13)	0.0388 (13)	0.0170 (12)	0.0040 (12)	−0.0066 (11)
C7	0.0477 (14)	0.0283 (11)	0.0269 (11)	0.0057 (10)	−0.0066 (11)	0.0049 (9)

Geometric parameters (Å, º) top

Ni1—N2	2.0990 (17)	N2—H2C	0.9300
Ni1—N2ⁱ	2.0990 (17)	O2—C9	1.254 (2)
Ni1—O1ⁱ	2.1110 (13)	O3—H3A	0.8400
Ni1—O1	2.1110 (13)	C2—C1ⁱ	1.501 (3)
Ni1—N1	2.1368 (16)	C2—H2A	0.9900
Ni1—N1ⁱ	2.1368 (16)	C2—H2B	0.9900
C10—O4	1.209 (3)	C9—C9ⁱ	1.543 (4)
C10—O3	1.302 (3)	C1—C2ⁱ	1.501 (3)
C10—C10ⁱⁱ	1.513 (4)	C1—H1A	0.9900
O1—C9	1.255 (2)	C1—H1B	0.9900
N1—C1	1.477 (3)	C6—C8	1.530 (3)
N1—C6	1.504 (2)	C6—C7	1.531 (3)
N1—H1C	0.9300	C4—H4A	0.9800
C3—N2	1.495 (3)	C4—H4B	0.9800
C3—C5	1.506 (3)	C4—H4C	0.9800
C3—C4	1.539 (3)	C8—H8A	0.9800
C3—H3	1.0000	C8—H8B	0.9800
C5—C6	1.535 (3)	C8—H8C	0.9800
C5—H5A	0.9900	C7—H7A	0.9800
C5—H5B	0.9900	C7—H7B	0.9800
N2—C2	1.475 (3)	C7—H7C	0.9800

N2—Ni1—N2ⁱ	100.97 (9)	Ni1—N2—H2C	107.5
N2—Ni1—O1ⁱ	166.48 (6)	C10—O3—H3A	109.5
N2ⁱ—Ni1—O1ⁱ	90.84 (6)	N2—C2—C1ⁱ	109.25 (19)
N2—Ni1—O1	90.84 (6)	N2—C2—H2A	109.8
N2ⁱ—Ni1—O1	166.48 (6)	C1ⁱ—C2—H2A	109.8
O1ⁱ—Ni1—O1	78.29 (7)	N2—C2—H2B	109.8
N2—Ni1—N1	91.42 (7)	C1ⁱ—C2—H2B	109.8
N2ⁱ—Ni1—N1	84.55 (6)	H2A—C2—H2B	108.3
O1ⁱ—Ni1—N1	83.10 (6)	O2—C9—O1	125.80 (19)
O1—Ni1—N1	101.88 (5)	O2—C9—C9ⁱ	118.43 (12)
N2—Ni1—N1ⁱ	84.55 (6)	O1—C9—C9ⁱ	115.74 (11)
N2ⁱ—Ni1—N1ⁱ	91.42 (7)	N1—C1—C2ⁱ	110.65 (19)
O1ⁱ—Ni1—N1ⁱ	101.88 (5)	N1—C1—H1A	109.5
O1—Ni1—N1ⁱ	83.10 (6)	C2ⁱ—C1—H1A	109.5
N1—Ni1—N1ⁱ	173.67 (9)	N1—C1—H1B	109.5
O4—C10—O3	126.15 (19)	C2ⁱ—C1—H1B	109.5
O4—C10—C10ⁱⁱ	120.8 (3)	H1A—C1—H1B	108.1
O3—C10—C10ⁱⁱ	113.0 (3)	N1—C6—C8	110.86 (18)
C9—O1—Ni1	113.59 (12)	N1—C6—C7	107.34 (15)
C1—N1—C6	114.16 (15)	C8—C6—C7	107.94 (18)
C1—N1—Ni1	105.25 (12)	N1—C6—C5	109.95 (17)
C6—N1—Ni1	120.54 (13)	C8—C6—C5	109.69 (18)
C1—N1—H1C	105.2	C7—C6—C5	111.02 (19)
C6—N1—H1C	105.2	C3—C4—H4A	109.5
Ni1—N1—H1C	105.2	C3—C4—H4B	109.5
N2—C3—C5	112.0 (2)	H4A—C4—H4B	109.5
N2—C3—C4	111.46 (19)	C3—C4—H4C	109.5
C5—C3—C4	109.2 (2)	H4A—C4—H4C	109.5
N2—C3—H3	108.0	H4B—C4—H4C	109.5
C5—C3—H3	108.0	C6—C8—H8A	109.5
C4—C3—H3	108.0	C6—C8—H8B	109.5
C3—C5—C6	119.2 (2)	H8A—C8—H8B	109.5
C3—C5—H5A	107.5	C6—C8—H8C	109.5
C6—C5—H5A	107.5	H8A—C8—H8C	109.5
C3—C5—H5B	107.5	H8B—C8—H8C	109.5
C6—C5—H5B	107.5	C6—C7—H7A	109.5
H5A—C5—H5B	107.0	C6—C7—H7B	109.5
C2—N2—C3	112.13 (17)	H7A—C7—H7B	109.5
C2—N2—Ni1	103.84 (12)	C6—C7—H7C	109.5
C3—N2—Ni1	117.82 (13)	H7A—C7—H7C	109.5
C2—N2—H2C	107.5	H7B—C7—H7C	109.5
C3—N2—H2C	107.5

N2—Ni1—O1—C9	−177.81 (13)	O1—Ni1—N2—C2	−60.63 (12)
N2ⁱ—Ni1—O1—C9	31.2 (3)	N1—Ni1—N2—C2	−162.53 (13)
O1ⁱ—Ni1—O1—C9	−5.92 (10)	N1ⁱ—Ni1—N2—C2	22.36 (12)
N1—Ni1—O1—C9	−86.19 (13)	N2ⁱ—Ni1—N2—C3	−122.59 (18)
N1ⁱ—Ni1—O1—C9	97.78 (13)	O1ⁱ—Ni1—N2—C3	27.8 (4)
N2—Ni1—N1—C1	−94.43 (13)	O1—Ni1—N2—C3	64.03 (16)
N2ⁱ—Ni1—N1—C1	6.46 (13)	N1—Ni1—N2—C3	−37.87 (16)
O1ⁱ—Ni1—N1—C1	97.97 (13)	N1ⁱ—Ni1—N2—C3	147.02 (16)
O1—Ni1—N1—C1	174.42 (12)	C3—N2—C2—C1ⁱ	−176.24 (19)
N1ⁱ—Ni1—N1—C1	−44.13 (12)	Ni1—N2—C2—C1ⁱ	−48.0 (2)
N2—Ni1—N1—C6	36.38 (14)	Ni1—O1—C9—O2	−163.44 (16)
N2ⁱ—Ni1—N1—C6	137.26 (14)	Ni1—O1—C9—C9ⁱ	14.9 (2)
O1ⁱ—Ni1—N1—C6	−131.22 (14)	C6—N1—C1—C2ⁱ	−169.19 (19)
O1—Ni1—N1—C6	−54.78 (14)	Ni1—N1—C1—C2ⁱ	−34.8 (2)
N1ⁱ—Ni1—N1—C6	86.67 (13)	C1—N1—C6—C8	−45.1 (2)
N2—C3—C5—C6	−70.9 (3)	Ni1—N1—C6—C8	−171.97 (14)
C4—C3—C5—C6	165.16 (19)	C1—N1—C6—C7	−162.80 (18)
C5—C3—N2—C2	177.2 (2)	Ni1—N1—C6—C7	70.36 (19)
C4—C3—N2—C2	−60.2 (2)	C1—N1—C6—C5	76.3 (2)
C5—C3—N2—Ni1	56.7 (2)	Ni1—N1—C6—C5	−50.5 (2)
C4—C3—N2—Ni1	179.33 (16)	C3—C5—C6—N1	66.3 (3)
N2ⁱ—Ni1—N2—C2	112.75 (13)	C3—C5—C6—C8	−171.6 (2)
O1ⁱ—Ni1—N2—C2	−96.8 (3)	C3—C5—C6—C7	−52.4 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O4ⁱⁱⁱ	0.93	2.17	3.075 (2)	164
N2—H2C···O2^iv	0.93	2.13	2.987 (2)	152
O3—H3A···O2^v	0.84	1.70	2.532 (2)	170

Symmetry codes: (iii) x, y−1, z; (iv) x, y, z+1; (v) −x+2, −y+1, z.

Experimental details

Crystal data
Chemical formula	[Ni(C₂O₄)(C₁₆H₃₆N₄)]·C₂H₂O₄
M_r	521.25
Crystal system, space group	Orthorhombic, P2₁2₁2
Temperature (K)	173
a, b, c (Å)	10.1261 (15), 15.515 (2), 8.0467 (11)
V (Å³)	1264.2 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.82
Crystal size (mm)	0.48 × 0.21 × 0.15

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.695, 0.887
No. of measured, independent and observed [I > 2σ(I)] reflections	5665, 2740, 2435
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.640

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.064, 1.08
No. of reflections	2740
No. of parameters	154
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.40, −0.19
Absolute structure	Flack (1983), 1131 Friedel pairs
Absolute structure parameter	0.027 (13)

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O4ⁱ	0.93	2.17	3.075 (2)	163.6
N2—H2C···O2ⁱⁱ	0.93	2.13	2.987 (2)	151.9
O3—H3A···O2ⁱⁱⁱ	0.84	1.70	2.532 (2)	170.4

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

Acknowledgements

This work was supported financially by the Foundation for University Key Teachers by the Education Department of Hunan Province and the Key Subject Construction Project of Hunan Province (No. 2006–180).

References

Bruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Curtis, N. F. (1965). J. Chem. Soc. A, pp. 924–931. CrossRef Web of Science Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals 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
Tait, A. M. & Busch, D. H. (1976). Inorg. Synth. 18, 4–7. Google Scholar
Tang, J. K., Gao, E. Q., Zhang, L., Liao, D. Z., Jiang, Z. H. & Yan, S. P. (2002). J. Coord. Chem. 55, 527–535. Web of Science CSD CrossRef CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.