catena-Poly[[bis­(3-carb­oxy-5-nitro­benzoato-κO1)copper(II)]-μ-1,3-di-4-pyridylpropane-κ2N:N′]

Sposato, L.K.; LaDuca, R.L.

doi:10.1107/S1600536809031821

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page m1082

doi:10.1107/S1600536809031821

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catena-Poly[[bis(3-carboxy-5-nitrobenzoato-κO¹)copper(II)]-μ-1,3-di-4-pyridylpropane-κ²N:N′]

Laura K. Sposato ^a and Robert L. LaDuca ^a ^*

^aLyman Briggs College, Department of Chemistry, Michigan State University, East Lansing, MI 48825, USA
^*Correspondence e-mail: laduca@msu.edu

(Received 7 August 2009; accepted 12 August 2009; online 19 August 2009)

In the title compound, [Cu(C₈H₄NO₆)₂(C₁₃H₁₄N₂)]_n, the square-planar coordinated Cu^II ion lies on an inversion centre and is coordinated by two protonated 5-nitroisophthalate ligands. The Cu^II ions are linked into a one-dimensional coordination polymer by tethering 1,3-di-4-pyridylpropane ligands, whose central methylene C atoms are situated on twofold rotation axes. The chains are oriented parallel to the c axis, and stack into a supramolecular three-dimensional structure through O—H⋯O hydrogen-bonding interactions.

Related literature

For some recent divalent copper dicarboxylate coordination polymers containing 1,3-di-4-pyridylpropane, see: Wang et al. (2009 ).

Experimental

Crystal data

[Cu(C₈H₄NO₆)₂(C₁₃H₁₄N₂)]
M_r = 682.05
Monoclinic, C 2/c
a = 25.2976 (8) Å
b = 5.3702 (2) Å
c = 21.3122 (7) Å
β = 115.865 (2)°
V = 2605.29 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.92 mm⁻¹
T = 173 K
0.22 × 0.22 × 0.11 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.821, T_max = 0.905
10349 measured reflections
2401 independent reflections
2087 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.112
S = 1.08
2401 reflections
213 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.10 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯O2ⁱ	0.85 (4)	1.86 (2)	2.668 (3)	158 (4)
Symmetry code: (i) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]$ .

Data collection: APEX2 (Bruker, 2006 ); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2007 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809031821/tk2526sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809031821/tk2526Isup2.hkl

checkCIF report

Comment top

The title compound, (I), was prepared by the hydrothermal reaction of copper nitrate, 5-nitroisophthalic acid (nip) and 1,3-di-4-pyridylpropame (dpp). Its asymmetric unit contains a copper atom on an inversion centre, one singly protonated nip (Hnip) ligand, and one-half of a dpp ligand, whose central methylene carbon atom is situated on a 2-fold axis. Operation of the inversion centre at Cu reveals a square planar coordination environment with trans O atom donors from protonated nip ligands and trans N donors from two dpp ligands (Fig. 1). The Hnip ligands are bound to Cu in a simple monodentate fashion via an O atom belonging to the non-protonated carboxylate terminus.

Operation of the 2-fold rotation axes indicates that dpp ligands connect neighboring Cu atoms into a one-dimensional [Cu(Hnip)₂(dpp)]_n coordination polymer chain (Fig. 2), which is oriented parallel to the c-axis. The methylene groups within the dpp ligands adopt a gauche-gauche conformation, providing a Cu···Cu separation of 10.656 (4) Å. Neighboring chains aggregate by hydrogen-bonding mechanisms (Table 1) involving the hydroxyl groups of the protonated Hnip ligands and unligated O atoms of the monodentate Hnip carboxylate groups, thus forming the three-dimensional supramolecular structure (Fig. 3).

Related literature top

For some recent divalent copper dicarboxylate coordination polymers containing 1,3-di-4-pyridylpropane, see: Wang et al. (2009).

Experimental top

All starting materials were obtained commercially. A mixture of copper nitrate trihydrate (90 mg, 0.37 mmol), 5-nitroisophthalic acid (79 mg, 0.37 mmol), 1,3-di-4-pyridylpropane (73 mg, 0.37 mmol) and 10.0 g water (550 mmol) was placed into a 23 ml Teflon-lined Parr Acid Digestion bomb, which was then heated under autogenous pressure at 363 K for 24 h. Blue blocks of (I) were obtained along with a light-blue amorphous powder.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2007); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The coordination environment of (I), showing 50% probability ellipsoids and atom numbering scheme. Hydrogen atom positions are shown as grey sticks. Color codes: dark blue Cu, light blue N, orange O, black C. Symmetry codes: (i) -x, -y, -z (ii) -x, y, -z + 1/2.
	Fig. 2. A view of the coordination polymer chain motif in (I).
	Fig. 3. Stacking diagram for (I), viewed down the b axis. Hydrogen bonding contacts are indicated as dashed bars.

catena-Poly[[bis(3-carboxy-5-nitrobenzoato-κO¹)copper(II)]-µ- 1,3-di-4-pyridylpropane-κ²N:N'] top

Crystal data top

[Cu(C₈H₄NO₆)₂(C₁₃H₁₄N₂)]	F(000) = 1396
M_r = 682.05	D_x = 1.739 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 10349 reflections
a = 25.2976 (8) Å	θ = 1.8–25.4°
b = 5.3702 (2) Å	µ = 0.92 mm⁻¹
c = 21.3122 (7) Å	T = 173 K
β = 115.865 (2)°	Block, blue
V = 2605.29 (15) Å³	0.22 × 0.22 × 0.11 mm
Z = 4

Data collection top

Bruker APEXII diffractometer	2401 independent reflections
Radiation source: fine-focus sealed tube	2087 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
ω and ϕ scans	θ_max = 25.4°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −30→28
T_min = 0.821, T_max = 0.905	k = −6→6
10349 measured reflections	l = −24→25

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.112	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ²(F_o²) + (0.0535P)² + 8.8582P] where P = (F_o² + 2F_c²)/3
2401 reflections	(Δ/σ)_max < 0.001
213 parameters	Δρ_max = 1.10 e Å⁻³
1 restraint	Δρ_min = −0.31 e Å⁻³

Crystal data top

[Cu(C₈H₄NO₆)₂(C₁₃H₁₄N₂)]	V = 2605.29 (15) Å³
M_r = 682.05	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 25.2976 (8) Å	µ = 0.92 mm⁻¹
b = 5.3702 (2) Å	T = 173 K
c = 21.3122 (7) Å	0.22 × 0.22 × 0.11 mm
β = 115.865 (2)°

Data collection top

Bruker APEXII diffractometer	2401 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2087 reflections with I > 2σ(I)
T_min = 0.821, T_max = 0.905	R_int = 0.032
10349 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	1 restraint
wR(F²) = 0.112	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	Δρ_max = 1.10 e Å⁻³
2401 reflections	Δρ_min = −0.31 e Å⁻³
213 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	Occ. (<1)
Cu1	0.0000	0.0000	0.0000	0.01865 (18)
O1	0.07835 (8)	−0.1413 (4)	0.04676 (10)	0.0209 (5)
O2	0.11395 (9)	0.1584 (4)	0.00388 (11)	0.0273 (5)
O3	0.31946 (10)	0.1103 (5)	0.04659 (13)	0.0332 (6)
H3A	0.3473 (12)	0.154 (7)	0.0365 (19)	0.040*
O4	0.37815 (10)	−0.2063 (5)	0.10363 (13)	0.0374 (6)
O5	0.30010 (10)	−0.7828 (4)	0.22279 (12)	0.0325 (6)
O6	0.20769 (10)	−0.7829 (4)	0.19827 (11)	0.0279 (5)
N1	0.01902 (10)	0.2420 (5)	0.07966 (12)	0.0207 (5)
N2	0.25020 (11)	−0.6974 (5)	0.19249 (12)	0.0222 (6)
C1	0.17873 (12)	−0.1639 (6)	0.07286 (14)	0.0180 (6)
C2	0.22615 (12)	−0.0740 (6)	0.06286 (14)	0.0178 (6)
H2	0.2213	0.0694	0.0348	0.021*
C3	0.28055 (12)	−0.1922 (6)	0.09360 (14)	0.0189 (6)
C4	0.28838 (12)	−0.3992 (6)	0.13549 (14)	0.0187 (6)
H4	0.3252	−0.4823	0.1562	0.022*
C5	0.24125 (13)	−0.4817 (5)	0.14633 (14)	0.0187 (6)
C6	0.18627 (12)	−0.3712 (6)	0.11546 (14)	0.0178 (6)
H6	0.1545	−0.4349	0.1231	0.021*
C7	0.11985 (12)	−0.0359 (6)	0.03800 (14)	0.0190 (6)
C8	0.33175 (12)	−0.0985 (6)	0.08267 (15)	0.0230 (7)
C11	0.06442 (14)	0.2091 (7)	0.14297 (17)	0.0299 (7)
H11	0.0897	0.0709	0.1492	0.036*
C12	0.07641 (14)	0.3641 (7)	0.19921 (16)	0.0300 (8)
H12	0.1088	0.3305	0.2428	0.036*
C13	0.04037 (13)	0.5719 (6)	0.19170 (16)	0.0255 (7)
C14	−0.00464 (13)	0.6150 (6)	0.12500 (16)	0.0270 (7)
H14	−0.0290	0.7579	0.1164	0.032*
C15	−0.01359 (13)	0.4504 (6)	0.07206 (16)	0.0265 (7)
H15	−0.0445	0.4844	0.0274	0.032*
C16	0.05196 (14)	0.7391 (7)	0.25328 (16)	0.0297 (7)
H16A	0.0841	0.8549	0.2586	0.036*
H16B	0.0662	0.6344	0.2957	0.036*
C17	0.0000	0.8934 (9)	0.2500	0.0293 (10)
H17A	−0.0137	1.0023	0.2084	0.035*	0.50
H17B	0.0137	1.0023	0.2916	0.035*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0127 (3)	0.0208 (3)	0.0223 (3)	0.0016 (2)	0.0075 (2)	−0.0009 (2)
O1	0.0152 (9)	0.0220 (12)	0.0241 (10)	0.0019 (9)	0.0072 (8)	0.0005 (9)
O2	0.0225 (10)	0.0269 (13)	0.0338 (12)	0.0092 (10)	0.0135 (9)	0.0115 (10)
O3	0.0267 (12)	0.0337 (14)	0.0471 (14)	0.0025 (11)	0.0235 (11)	0.0139 (12)
O4	0.0198 (11)	0.0438 (15)	0.0491 (14)	0.0036 (11)	0.0153 (10)	0.0089 (12)
O5	0.0296 (12)	0.0306 (14)	0.0346 (12)	0.0131 (10)	0.0116 (10)	0.0145 (11)
O6	0.0330 (12)	0.0236 (12)	0.0294 (11)	−0.0015 (10)	0.0158 (10)	0.0040 (10)
N1	0.0171 (12)	0.0233 (14)	0.0213 (12)	0.0037 (11)	0.0079 (10)	0.0006 (11)
N2	0.0278 (14)	0.0191 (14)	0.0196 (12)	0.0036 (11)	0.0103 (11)	0.0000 (10)
C1	0.0160 (13)	0.0193 (15)	0.0174 (13)	0.0025 (12)	0.0061 (11)	−0.0026 (12)
C2	0.0197 (14)	0.0177 (15)	0.0157 (13)	0.0016 (12)	0.0075 (11)	0.0016 (11)
C3	0.0177 (14)	0.0212 (16)	0.0172 (13)	0.0008 (12)	0.0071 (11)	−0.0022 (12)
C4	0.0152 (13)	0.0203 (15)	0.0173 (13)	0.0032 (12)	0.0039 (11)	−0.0017 (12)
C5	0.0223 (14)	0.0176 (15)	0.0139 (13)	0.0015 (12)	0.0059 (11)	0.0002 (12)
C6	0.0161 (13)	0.0194 (16)	0.0173 (13)	−0.0022 (12)	0.0066 (11)	−0.0038 (12)
C7	0.0169 (14)	0.0216 (17)	0.0158 (13)	0.0018 (12)	0.0046 (11)	−0.0030 (12)
C8	0.0175 (14)	0.0279 (17)	0.0222 (15)	−0.0001 (13)	0.0072 (12)	−0.0001 (13)
C11	0.0274 (16)	0.0300 (19)	0.0332 (17)	0.0041 (14)	0.0142 (14)	0.0028 (15)
C12	0.0304 (17)	0.032 (2)	0.0257 (16)	−0.0019 (15)	0.0105 (13)	0.0022 (14)
C13	0.0227 (15)	0.0277 (18)	0.0283 (16)	−0.0034 (13)	0.0129 (13)	0.0012 (14)
C14	0.0239 (15)	0.0255 (18)	0.0327 (17)	−0.0002 (14)	0.0133 (13)	0.0007 (14)
C15	0.0217 (15)	0.0339 (19)	0.0236 (15)	0.0000 (14)	0.0098 (13)	0.0031 (14)
C16	0.0268 (17)	0.034 (2)	0.0261 (16)	−0.0030 (15)	0.0092 (13)	−0.0004 (14)
C17	0.033 (2)	0.030 (3)	0.025 (2)	0.000	0.0131 (19)	0.000

Geometric parameters (Å, º) top

Cu1—O1	1.9427 (19)	C3—C8	1.500 (4)
Cu1—O1ⁱ	1.9427 (19)	C4—C5	1.383 (4)
Cu1—N1ⁱ	2.022 (2)	C4—H4	0.9500
Cu1—N1	2.022 (2)	C5—C6	1.386 (4)
O1—C7	1.276 (3)	C6—H6	0.9500
O2—C7	1.243 (4)	C11—C12	1.380 (5)
O3—C8	1.318 (4)	C11—H11	0.9500
O3—H3A	0.85 (4)	C12—C13	1.405 (5)
O4—C8	1.206 (4)	C12—H12	0.9500
O5—N2	1.229 (3)	C13—C14	1.399 (4)
O6—N2	1.224 (3)	C13—C16	1.510 (5)
N1—C11	1.349 (4)	C14—C15	1.372 (5)
N1—C15	1.358 (4)	C14—H14	0.9500
N2—C5	1.472 (4)	C15—H15	0.9500
C1—C2	1.393 (4)	C16—C17	1.529 (4)
C1—C6	1.396 (4)	C16—H16A	0.9900
C1—C7	1.509 (4)	C16—H16B	0.9900
C2—C3	1.392 (4)	C17—C16ⁱⁱ	1.530 (4)
C2—H2	0.9500	C17—H17A	0.9900
C3—C4	1.385 (4)	C17—H17B	0.9900

O1—Cu1—O1ⁱ	180.00 (11)	O2—C7—C1	120.7 (3)
O1—Cu1—N1ⁱ	89.75 (9)	O1—C7—C1	115.1 (3)
O1ⁱ—Cu1—N1ⁱ	90.25 (9)	O4—C8—O3	124.6 (3)
O1—Cu1—N1	90.25 (9)	O4—C8—C3	123.3 (3)
O1ⁱ—Cu1—N1	89.75 (9)	O3—C8—C3	112.1 (2)
N1ⁱ—Cu1—N1	180.0	N1—C11—C12	124.0 (3)
C7—O1—Cu1	118.18 (18)	N1—C11—H11	118.0
C8—O3—H3A	112 (3)	C12—C11—H11	118.0
C11—N1—C15	115.8 (3)	C11—C12—C13	119.6 (3)
C11—N1—Cu1	122.9 (2)	C11—C12—H12	120.2
C15—N1—Cu1	121.3 (2)	C13—C12—H12	120.2
O6—N2—O5	123.6 (3)	C14—C13—C12	116.5 (3)
O6—N2—C5	118.5 (2)	C14—C13—C16	123.2 (3)
O5—N2—C5	117.9 (2)	C12—C13—C16	120.2 (3)
C2—C1—C6	119.6 (3)	C15—C14—C13	119.9 (3)
C2—C1—C7	119.9 (3)	C15—C14—H14	120.1
C6—C1—C7	120.6 (2)	C13—C14—H14	120.1
C3—C2—C1	120.7 (3)	N1—C15—C14	124.0 (3)
C3—C2—H2	119.7	N1—C15—H15	118.0
C1—C2—H2	119.7	C14—C15—H15	118.0
C4—C3—C2	120.2 (3)	C13—C16—C17	116.5 (2)
C4—C3—C8	118.6 (3)	C13—C16—H16A	108.2
C2—C3—C8	121.2 (3)	C17—C16—H16A	108.2
C5—C4—C3	118.3 (3)	C13—C16—H16B	108.2
C5—C4—H4	120.9	C17—C16—H16B	108.2
C3—C4—H4	120.9	H16A—C16—H16B	107.3
C4—C5—C6	122.9 (3)	C16—C17—C16ⁱⁱ	114.4 (4)
C4—C5—N2	118.1 (3)	C16—C17—H17A	108.7
C6—C5—N2	118.9 (3)	C16ⁱⁱ—C17—H17A	108.7
C5—C6—C1	118.3 (3)	C16—C17—H17B	108.7
C5—C6—H6	120.9	C16ⁱⁱ—C17—H17B	108.7
C1—C6—H6	120.9	H17A—C17—H17B	107.6
O2—C7—O1	124.2 (3)

N1ⁱ—Cu1—O1—C7	94.8 (2)	Cu1—O1—C7—C1	−176.93 (17)
N1—Cu1—O1—C7	−85.2 (2)	C2—C1—C7—O2	−4.5 (4)
O1—Cu1—N1—C11	−17.8 (2)	C6—C1—C7—O2	175.1 (3)
O1ⁱ—Cu1—N1—C11	162.2 (2)	C2—C1—C7—O1	175.8 (2)
O1—Cu1—N1—C15	161.9 (2)	C6—C1—C7—O1	−4.6 (4)
O1ⁱ—Cu1—N1—C15	−18.1 (2)	C4—C3—C8—O4	6.5 (5)
C6—C1—C2—C3	1.5 (4)	C2—C3—C8—O4	−173.9 (3)
C7—C1—C2—C3	−178.9 (3)	C4—C3—C8—O3	−174.8 (3)
C1—C2—C3—C4	−1.0 (4)	C2—C3—C8—O3	4.8 (4)
C1—C2—C3—C8	179.4 (3)	C15—N1—C11—C12	4.0 (5)
C2—C3—C4—C5	−0.8 (4)	Cu1—N1—C11—C12	−176.3 (2)
C8—C3—C4—C5	178.9 (3)	N1—C11—C12—C13	−0.7 (5)
C3—C4—C5—C6	2.1 (4)	C11—C12—C13—C14	−3.1 (5)
C3—C4—C5—N2	−178.3 (2)	C11—C12—C13—C16	178.3 (3)
O6—N2—C5—C4	−174.7 (3)	C12—C13—C14—C15	3.4 (5)
O5—N2—C5—C4	4.8 (4)	C16—C13—C14—C15	−178.0 (3)
O6—N2—C5—C6	5.0 (4)	C11—N1—C15—C14	−3.6 (4)
O5—N2—C5—C6	−175.5 (3)	Cu1—N1—C15—C14	176.7 (2)
C4—C5—C6—C1	−1.5 (4)	C13—C14—C15—N1	−0.1 (5)
N2—C5—C6—C1	178.8 (2)	C14—C13—C16—C17	24.3 (5)
C2—C1—C6—C5	−0.3 (4)	C12—C13—C16—C17	−157.2 (3)
C7—C1—C6—C5	−179.9 (2)	C13—C16—C17—C16ⁱⁱ	62.0 (2)
Cu1—O1—C7—O2	3.4 (4)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O2ⁱⁱⁱ	0.85 (4)	1.86 (2)	2.668 (3)	158 (4)

Symmetry code: (iii) −x+1/2, −y+1/2, −z.

Experimental details

Crystal data
Chemical formula	[Cu(C₈H₄NO₆)₂(C₁₃H₁₄N₂)]
M_r	682.05
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	25.2976 (8), 5.3702 (2), 21.3122 (7)
β (°)	115.865 (2)
V (Å³)	2605.29 (15)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.92
Crystal size (mm)	0.22 × 0.22 × 0.11

Data collection
Diffractometer	Bruker APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.821, 0.905
No. of measured, independent and observed [I > 2σ(I)] reflections	10349, 2401, 2087
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.604

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.112, 1.08
No. of reflections	2401
No. of parameters	213
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.10, −0.31

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), CrystalMaker (Palmer, 2007).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O2ⁱ	0.85 (4)	1.86 (2)	2.668 (3)	158 (4)

Symmetry code: (i) −x+1/2, −y+1/2, −z.

Acknowledgements

We gratefully acknowledge the donors of the American Chemical Society Petroleum Research Fund for funding this work.

References

Bruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Palmer, D. (2007). CrystalMaker. CrystalMaker Software, Bicester, England. 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
Wang, G. R., Li, Z. G., Jia, H. Q., Hu, N. H. & Xu, J. W. (2009). CrystEngComm, 11, 292–297. Web of Science CSD CrossRef CAS Google Scholar

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