{2,2′-[(5-Bromo­pyridine-2,3-di­yl)bis­(nitrilo­methyl­idyne)]diphenolato}chlorido(N,N-dimethyl­formamide)iron(III)

Sheng, N.; Ni, Z.

doi:10.1107/S1600536809031432

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 10| October 2009| Page m1202

doi:10.1107/S1600536809031432

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{2,2′-[(5-Bromopyridine-2,3-diyl)bis(nitrilomethylidyne)]diphenolato}chlorido(N,N-dimethylformamide)iron(III)

Ning Sheng ^a ^* and Zhonghai Ni ^b

^aDepartment of Chemistry & Chemical Engineering, Jining University, Qufu 273155, People's Republic of China, and ^bSchool of Chemistry & Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
^*Correspondence e-mail: shengning@mail.sdu.edu.cn

(Received 30 July 2009; accepted 10 August 2009; online 12 September 2009)

In the title complex, [Fe(C₁₉H₁₂BrClN₃O₂)(C₃H₇NO)], the Fe^III atom is coordinated by an N,N,O,O-tetradentate Schiff base ligand and trans coordinated by a chloride anion and the O atom of an N,N-dimethylformamide molecule. The resulting geometry is distorted octahedral within a ClN₂O₃ donor set.

Related literature

For the optical, electronic, magnetic, biological and catalytic properties of complexes containing salicylaldehyde ligands, see: Alam et al. (2003 ); Oshiob et al. (2005 ); Zelewsky & von Knof (1999 ).

Experimental

Crystal data

[Fe(C₁₉H₁₂BrClN₃O₂)(C₃H₇NO)]
M_r = 558.62
Monoclinic, P 2₁ /c
a = 13.1626 (11) Å
b = 15.3553 (13) Å
c = 12.6376 (11) Å
β = 118.186 (1)°
V = 2251.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 2.60 mm⁻¹
T = 293 K
0.21 × 0.15 × 0.11 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.612, T_max = 0.763
11869 measured reflections
4421 independent reflections
3468 reflections with I > 2σ(I)
R_int = 0.023

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.117
S = 1.04
4421 reflections
291 parameters
H-atom parameters constrained
Δρ_max = 1.35 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97; software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031432/tk2520sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809031432/tk2520Isup2.hkl

checkCIF report

Comment top

The synthesis of complexes containing salicylaldehyde ligands has attracted continuous research interest not only because of their appealing structural and topological novelty, but also due to their unusual optical, electronic, magnetic, biological, and catalytic properties (Alam et al., 2003; Zelewsky et al., 1999; Oshiob et al., 2005). In the present paper, we describe the synthesis and structural characterization of the title compound, (I).

In (I), the Fe^III atom is tetracoordinated by Schiff base ligand via two N and two O atoms, Fig. 1. In addition the metal centre is coordinated by a Cl anion and the O atom of a N,N-dimethylformamide molecule. The resulting coordination geometry is based on a distorted octahedron in which the Cl and N,N-dimethylformamide-O atoms define axial sites.

Related literature top

For the optical, electronic, magnetic, biological and catalytic properties of complexes containing salicylaldehyde ligands, see: Alam et al. (2003); Oshiob et al. (2005); Zelewsky & von Knof (1999).

Experimental top

Condensation of 4-bromo-o-phenylenediamine with salicylaldehyde in a 1:2 molar ratio in ethanol gave the Schiff base ligand. FeCl₃ (0.1 mmol) was added dropwise to a solution of the Schiff base (0.1 mmol) in methanol. The resulting solution was stirred at room temperature for 30 minutes. After filtering, the insoluble solids were dissolved in DMF and ether. The product was isolated red-brown crystals in a yield of 45% after a few weeks.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms have been omitted for clarity.

{2,2'-[(5-Bromopyridine-2,3- diyl)bis(nitrilomethylidyne)]diphenolato}chlorido(N,N- dimethylformamide)iron(III) top

Crystal data top

[Fe(C₁₉H₁₂BrClN₃O₂)(C₃H₇NO)]	Z = 4
M_r = 558.62	F(000) = 1122
Monoclinic, P2₁/c	D_x = 1.647 Mg m⁻³
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 13.1626 (11) Å	µ = 2.60 mm⁻¹
b = 15.3553 (13) Å	T = 293 K
c = 12.6376 (11) Å	Block, red-brown
β = 118.186 (1)°	0.21 × 0.15 × 0.11 mm
V = 2251.4 (3) Å³

Data collection top

Bruker APEXII CCD area-detector diffractometer	4421 independent reflections
Radiation source: fine-focus sealed tube	3468 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→16
T_min = 0.612, T_max = 0.763	k = −14→18
11869 measured reflections	l = −15→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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.117	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0664P)² + 1.0974P] where P = (F_o² + 2F_c²)/3
4421 reflections	(Δ/σ)_max = 0.002
291 parameters	Δρ_max = 1.35 e Å⁻³
0 restraints	Δρ_min = −0.39 e Å⁻³

Crystal data top

[Fe(C₁₉H₁₂BrClN₃O₂)(C₃H₇NO)]	V = 2251.4 (3) Å³
M_r = 558.62	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 13.1626 (11) Å	µ = 2.60 mm⁻¹
b = 15.3553 (13) Å	T = 293 K
c = 12.6376 (11) Å	0.21 × 0.15 × 0.11 mm
β = 118.186 (1)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	4421 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	3468 reflections with I > 2σ(I)
T_min = 0.612, T_max = 0.763	R_int = 0.023
11869 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.117	H-atom parameters constrained
S = 1.04	Δρ_max = 1.35 e Å⁻³
4421 reflections	Δρ_min = −0.39 e Å⁻³
291 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
Fe1	0.81172 (4)	0.45734 (3)	0.12689 (4)	0.04193 (15)
Br1	0.45611 (3)	0.63148 (3)	0.36373 (4)	0.06309 (16)
Cl1	0.68099 (7)	0.34010 (6)	0.05361 (9)	0.0584 (3)
O1	0.94591 (19)	0.38509 (16)	0.1821 (2)	0.0511 (6)
O2	0.78233 (19)	0.49869 (16)	−0.0266 (2)	0.0505 (6)
O3	0.9319 (2)	0.56438 (16)	0.2007 (2)	0.0555 (6)
N1	0.8280 (2)	0.45132 (16)	0.3011 (2)	0.0412 (6)
N2	0.6755 (2)	0.54061 (16)	0.1157 (2)	0.0401 (6)
N3	1.0807 (2)	0.63665 (18)	0.1998 (3)	0.0498 (7)
N4	0.7329 (2)	0.48025 (19)	0.4177 (3)	0.0501 (7)
C1	0.7382 (3)	0.4908 (2)	0.3158 (3)	0.0410 (7)
C2	0.6585 (3)	0.53962 (19)	0.2178 (3)	0.0394 (7)
C3	0.5712 (3)	0.5822 (2)	0.2311 (3)	0.0450 (7)
H3	0.5163	0.6158	0.1694	0.054*
C4	0.5694 (3)	0.5727 (2)	0.3380 (3)	0.0472 (8)
C5	0.6484 (3)	0.5206 (2)	0.4282 (3)	0.0515 (8)
H5	0.6426	0.5135	0.4982	0.062*
C6	0.9158 (3)	0.4183 (2)	0.3952 (3)	0.0452 (7)
H6	0.9172	0.4251	0.4690	0.054*
C7	1.0095 (3)	0.3728 (2)	0.3937 (3)	0.0454 (8)
C8	1.0937 (3)	0.3383 (2)	0.5057 (3)	0.0551 (9)
H8	1.0876	0.3493	0.5748	0.066*
C9	1.1837 (3)	0.2891 (3)	0.5130 (4)	0.0632 (11)
H9	1.2383	0.2667	0.5864	0.076*
C10	1.1924 (3)	0.2731 (2)	0.4092 (4)	0.0612 (10)
H10	1.2529	0.2392	0.4141	0.073*
C11	1.1146 (3)	0.3058 (2)	0.3007 (4)	0.0547 (9)
H11	1.1235	0.2947	0.2332	0.066*
C12	1.0196 (3)	0.3567 (2)	0.2898 (3)	0.0448 (8)
C13	0.6053 (3)	0.5821 (2)	0.0183 (3)	0.0414 (7)
H13	0.5427	0.6095	0.0191	0.050*
C14	0.6146 (3)	0.5897 (2)	−0.0883 (3)	0.0424 (7)
C15	0.5322 (3)	0.6421 (2)	−0.1808 (3)	0.0524 (9)
H15	0.4718	0.6658	−0.1716	0.063*
C16	0.5389 (3)	0.6588 (3)	−0.2836 (3)	0.0594 (10)
H16	0.4838	0.6936	−0.3434	0.071*
C17	0.6287 (3)	0.6233 (3)	−0.2976 (4)	0.0604 (10)
H17	0.6344	0.6355	−0.3667	0.072*
C18	0.7094 (3)	0.5704 (2)	−0.2111 (3)	0.0539 (9)
H18	0.7687	0.5475	−0.2229	0.065*
C19	0.7045 (3)	0.5504 (2)	−0.1065 (3)	0.0439 (7)
C20	0.9823 (3)	0.5955 (2)	0.1477 (3)	0.0512 (8)
H20	0.9474	0.5890	0.0647	0.061*
C21	1.1401 (4)	0.6472 (3)	0.3283 (4)	0.0786 (13)
H21A	1.1111	0.6978	0.3498	0.118*
H21B	1.2212	0.6541	0.3553	0.118*
H21C	1.1277	0.5967	0.3654	0.118*
C22	1.1359 (3)	0.6718 (3)	0.1329 (4)	0.0615 (10)
H22A	1.0840	0.6676	0.0484	0.092*
H22B	1.2047	0.6394	0.1519	0.092*
H22C	1.1553	0.7318	0.1542	0.092*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Fe1	0.0323 (2)	0.0442 (3)	0.0446 (3)	0.00752 (19)	0.0144 (2)	0.0030 (2)
Br1	0.0530 (2)	0.0760 (3)	0.0671 (3)	0.01648 (18)	0.0340 (2)	0.00264 (19)
Cl1	0.0388 (4)	0.0490 (5)	0.0738 (6)	0.0018 (4)	0.0156 (4)	−0.0049 (4)
O1	0.0363 (12)	0.0610 (15)	0.0522 (14)	0.0125 (10)	0.0177 (11)	0.0032 (11)
O2	0.0456 (13)	0.0555 (14)	0.0484 (13)	0.0124 (11)	0.0205 (11)	0.0053 (11)
O3	0.0466 (13)	0.0568 (15)	0.0615 (15)	−0.0083 (11)	0.0242 (12)	−0.0003 (12)
N1	0.0337 (13)	0.0393 (14)	0.0467 (15)	0.0040 (11)	0.0158 (12)	0.0030 (11)
N2	0.0331 (13)	0.0386 (14)	0.0421 (14)	0.0028 (11)	0.0124 (11)	0.0006 (11)
N3	0.0424 (15)	0.0472 (16)	0.0608 (19)	0.0015 (12)	0.0252 (14)	0.0027 (13)
N4	0.0489 (16)	0.0571 (17)	0.0465 (16)	0.0089 (14)	0.0244 (14)	0.0070 (13)
C1	0.0333 (16)	0.0375 (16)	0.0491 (18)	0.0010 (13)	0.0169 (14)	−0.0013 (13)
C2	0.0326 (15)	0.0386 (16)	0.0434 (17)	−0.0005 (12)	0.0151 (13)	−0.0031 (13)
C3	0.0350 (16)	0.0421 (17)	0.0494 (19)	0.0038 (13)	0.0131 (14)	0.0007 (14)
C4	0.0375 (17)	0.0488 (19)	0.057 (2)	0.0019 (14)	0.0239 (16)	−0.0022 (16)
C5	0.053 (2)	0.055 (2)	0.051 (2)	0.0086 (17)	0.0283 (17)	0.0060 (16)
C6	0.0380 (17)	0.0472 (18)	0.0455 (19)	0.0030 (14)	0.0157 (15)	0.0015 (14)
C7	0.0305 (16)	0.0424 (18)	0.054 (2)	0.0017 (13)	0.0119 (14)	0.0072 (14)
C8	0.0396 (18)	0.056 (2)	0.055 (2)	0.0002 (16)	0.0102 (16)	0.0072 (17)
C9	0.0354 (18)	0.057 (2)	0.074 (3)	0.0052 (16)	0.0073 (18)	0.019 (2)
C10	0.0312 (17)	0.051 (2)	0.090 (3)	0.0099 (15)	0.0195 (19)	0.0130 (19)
C11	0.0398 (18)	0.0478 (19)	0.076 (3)	0.0064 (15)	0.0266 (18)	0.0050 (17)
C12	0.0274 (15)	0.0389 (16)	0.060 (2)	0.0006 (12)	0.0140 (15)	0.0058 (14)
C13	0.0313 (15)	0.0369 (16)	0.0504 (19)	0.0021 (13)	0.0145 (14)	0.0007 (14)
C14	0.0333 (15)	0.0376 (16)	0.0442 (18)	−0.0038 (13)	0.0084 (14)	0.0019 (13)
C15	0.0421 (19)	0.053 (2)	0.052 (2)	0.0020 (15)	0.0136 (16)	0.0062 (16)
C16	0.054 (2)	0.059 (2)	0.051 (2)	0.0041 (18)	0.0129 (18)	0.0119 (17)
C17	0.061 (2)	0.068 (2)	0.046 (2)	−0.0066 (19)	0.0198 (18)	0.0068 (17)
C18	0.052 (2)	0.059 (2)	0.052 (2)	−0.0045 (17)	0.0257 (18)	−0.0023 (17)
C19	0.0378 (17)	0.0435 (18)	0.0429 (18)	−0.0063 (13)	0.0128 (14)	−0.0031 (14)
C20	0.0449 (19)	0.051 (2)	0.053 (2)	−0.0002 (16)	0.0191 (17)	−0.0008 (16)
C21	0.061 (3)	0.101 (3)	0.064 (3)	−0.027 (2)	0.022 (2)	−0.004 (2)
C22	0.056 (2)	0.062 (2)	0.080 (3)	0.0015 (18)	0.043 (2)	0.008 (2)

Geometric parameters (Å, º) top

Fe1—O2	1.900 (2)	C7—C8	1.424 (5)
Fe1—O1	1.917 (2)	C8—C9	1.371 (5)
Fe1—N1	2.110 (3)	C8—H8	0.9300
Fe1—N2	2.152 (3)	C9—C10	1.391 (6)
Fe1—O3	2.164 (2)	C9—H9	0.9300
Fe1—Cl1	2.3566 (10)	C10—C11	1.361 (5)
Br1—C4	1.899 (3)	C10—H10	0.9300
O1—C12	1.317 (4)	C11—C12	1.425 (5)
O2—C19	1.312 (4)	C11—H11	0.9300
O3—C20	1.238 (4)	C13—C14	1.414 (5)
N1—C6	1.307 (4)	C13—H13	0.9300
N1—C1	1.416 (4)	C14—C15	1.412 (5)
N2—C13	1.304 (4)	C14—C19	1.441 (5)
N2—C2	1.409 (4)	C15—C16	1.367 (5)
N3—C20	1.306 (4)	C15—H15	0.9300
N3—C21	1.441 (5)	C16—C17	1.388 (6)
N3—C22	1.454 (5)	C16—H16	0.9300
N4—C1	1.332 (4)	C17—C18	1.373 (5)
N4—C5	1.334 (4)	C17—H17	0.9300
C1—C2	1.403 (4)	C18—C19	1.388 (5)
C2—C3	1.399 (4)	C18—H18	0.9300
C3—C4	1.370 (5)	C20—H20	0.9300
C3—H3	0.9300	C21—H21A	0.9600
C4—C5	1.378 (5)	C21—H21B	0.9600
C5—H5	0.9300	C21—H21C	0.9600
C6—C7	1.426 (5)	C22—H22A	0.9600
C6—H6	0.9300	C22—H22B	0.9600
C7—C12	1.404 (5)	C22—H22C	0.9600

O2—Fe1—O1	105.85 (10)	C9—C8—H8	119.5
O2—Fe1—N1	162.06 (10)	C7—C8—H8	119.5
O1—Fe1—N1	88.45 (10)	C8—C9—C10	119.1 (3)
O2—Fe1—N2	88.45 (10)	C8—C9—H9	120.5
O1—Fe1—N2	164.57 (11)	C10—C9—H9	120.5
N1—Fe1—N2	76.44 (10)	C11—C10—C9	121.9 (3)
O2—Fe1—O3	86.61 (10)	C11—C10—H10	119.1
O1—Fe1—O3	85.54 (10)	C9—C10—H10	119.1
N1—Fe1—O3	83.71 (10)	C10—C11—C12	120.5 (4)
N2—Fe1—O3	89.66 (10)	C10—C11—H11	119.7
O2—Fe1—Cl1	95.47 (8)	C12—C11—H11	119.7
O1—Fe1—Cl1	94.43 (8)	O1—C12—C7	124.0 (3)
N1—Fe1—Cl1	94.13 (8)	O1—C12—C11	117.8 (3)
N2—Fe1—Cl1	89.83 (7)	C7—C12—C11	118.2 (3)
O3—Fe1—Cl1	177.85 (8)	N2—C13—C14	126.8 (3)
C12—O1—Fe1	132.1 (2)	N2—C13—H13	116.6
C19—O2—Fe1	134.1 (2)	C14—C13—H13	116.6
C20—O3—Fe1	121.9 (2)	C15—C14—C13	117.3 (3)
C6—N1—C1	118.7 (3)	C15—C14—C19	118.3 (3)
C6—N1—Fe1	125.2 (2)	C13—C14—C19	124.4 (3)
C1—N1—Fe1	116.0 (2)	C16—C15—C14	121.7 (4)
C13—N2—C2	121.4 (3)	C16—C15—H15	119.2
C13—N2—Fe1	123.3 (2)	C14—C15—H15	119.2
C2—N2—Fe1	114.89 (19)	C15—C16—C17	119.3 (4)
C20—N3—C21	120.2 (3)	C15—C16—H16	120.4
C20—N3—C22	122.4 (3)	C17—C16—H16	120.4
C21—N3—C22	117.3 (3)	C18—C17—C16	121.1 (4)
C1—N4—C5	117.8 (3)	C18—C17—H17	119.5
N4—C1—C2	124.0 (3)	C16—C17—H17	119.5
N4—C1—N1	120.2 (3)	C17—C18—C19	121.5 (4)
C2—C1—N1	115.8 (3)	C17—C18—H18	119.2
C3—C2—C1	117.2 (3)	C19—C18—H18	119.2
C3—C2—N2	126.8 (3)	O2—C19—C18	119.8 (3)
C1—C2—N2	116.0 (3)	O2—C19—C14	122.1 (3)
C4—C3—C2	117.8 (3)	C18—C19—C14	118.1 (3)
C4—C3—H3	121.1	O3—C20—N3	124.8 (4)
C2—C3—H3	121.1	O3—C20—H20	117.6
C3—C4—C5	121.3 (3)	N3—C20—H20	117.6
C3—C4—Br1	120.0 (3)	N3—C21—H21A	109.5
C5—C4—Br1	118.7 (3)	N3—C21—H21B	109.5
N4—C5—C4	121.8 (3)	H21A—C21—H21B	109.5
N4—C5—H5	119.1	N3—C21—H21C	109.5
C4—C5—H5	119.1	H21A—C21—H21C	109.5
N1—C6—C7	125.2 (3)	H21B—C21—H21C	109.5
N1—C6—H6	117.4	N3—C22—H22A	109.5
C7—C6—H6	117.4	N3—C22—H22B	109.5
C12—C7—C8	119.4 (3)	H22A—C22—H22B	109.5
C12—C7—C6	124.3 (3)	N3—C22—H22C	109.5
C8—C7—C6	116.2 (3)	H22A—C22—H22C	109.5
C9—C8—C7	120.9 (4)	H22B—C22—H22C	109.5

Experimental details

Crystal data
Chemical formula	[Fe(C₁₉H₁₂BrClN₃O₂)(C₃H₇NO)]
M_r	558.62
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	13.1626 (11), 15.3553 (13), 12.6376 (11)
β (°)	118.186 (1)
V (Å³)	2251.4 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.60
Crystal size (mm)	0.21 × 0.15 × 0.11

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.612, 0.763
No. of measured, independent and observed [I > 2σ(I)] reflections	11869, 4421, 3468
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.117, 1.04
No. of reflections	4421
No. of parameters	291
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.35, −0.39

Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008).

Acknowledgements

This work was supported by the Postdoctoral Scientific Special Foundation of China (No. 200801414) and the Postdoctoral Scientific Foundation of Shandong Province (No. 200701010). The authors also acknowledge Jining University and Shandong University for support of this work.

References

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