6,6′-Dieth­oxy-2,2′-[propane-1,2-diyl­bis(nitrilo­methyl­idyne)]diphenol

Jia, Z.

doi:10.1107/S1600536809003328

organic compounds

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ISSN: 2056-9890

Volume 65| Part 3| March 2009| Page o646

doi:10.1107/S1600536809003328

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6,6′-Diethoxy-2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenol

Zhen Jia ^a ^*

^aDepartment of Chemistry, Dezhou University, Dezhou 253023, People's Republic of China
^*Correspondence e-mail: dzxyjz@126.com

(Received 22 January 2009; accepted 27 January 2009; online 28 February 2009)

In the title molecule, C₂₁H₂₆N₂O₄, the dihedral angle between the two benzene rings is 88.4 (3)°. Two fairly strong intramolecular O—H⋯N hydrogen bonds may, in part, influence the molecular conformation.

Related literature

For background information on the coordination ability of tetradentate Schiff-base ligands, see: Bermejo et al. (2007 ); Ni et al. (2005 ); Nayak et al., 2006 ; Mohanta et al., 2002 ; Saha et al. (2007 ); Wang et al. (2008 ); Yu et al. (2007 ).

Experimental

Crystal data

C₂₁H₂₆N₂O₄
M_r = 370.44
Triclinic, $[P \overline 1]$
a = 9.140 (3) Å
b = 11.451 (4) Å
c = 13.013 (5) Å
α = 113.845 (5)°
β = 109.628 (6)°
γ = 108.812 (5)°
V = 993.5 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 273 (2) K
0.12 × 0.11 × 0.09 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.990, T_max = 0.992
4894 measured reflections
3451 independent reflections
2325 reflections with I > 2σ(I)
R_int = 0.030

Refinement

R[F² > 2σ(F²)] = 0.066
wR(F²) = 0.193
S = 1.00
3451 reflections
249 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯N2	0.82	1.89	2.614 (3)	147
O1—H1⋯N1	0.82	1.85	2.576 (2)	146

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT-Plus (Bruker, 2001 ); data reduction: SAINT-Plus; 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/S1600536809003328/lh2762sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809003328/lh2762Isup2.hkl

checkCIF report

Comment top

Among the tetradentate schiff-base ligands studied intensely during the past several decades, the planar, salen types and their complexes (with interesting magnetic properties) have been given much attention due to their excellent coordination ability, utilizing two N atoms and two O atoms (Ni et al., 2005; Wang et al., 2008; Yu et al., 2007; Nayak et al., 2006; Mohanta et al., 2002; Saha et al., 2007).

Herein, we report the synthesis and crystal structure of a new tetradentate Schiff base ligand, N,N'-bis(2-hydroxy-3-ethoxybenzylidene)- 1,2-diaminopropane. The molecular structure of the title compound is shown in Fig. 1. The molecule possesses an O₂N₂ donor set affording a potentially tetradentate ligand. The imide bond lengths 1.262 (3) for N1—C7 and 1.263 (3) Å for N2—C16 are slightly shorter than that of N,N'-bis(2-hydroxy-3-methoxybenzylidene)ethylenediamine (1.272 Å) (Bermejo, et al., 2007). The C—N bond distance of 1.461 (3) Å is in agreement well with that found in the same compound. Two fairly strong intramolecular O···H—N hydrogen bonds may in part influence the molecular conformation.

Related literature top

For background information, see: Bermejo et al. (2007); Ni et al. (2005); Nayak et al., 2006; Mohanta et al., 2002; Saha et al. (2007); Wang et al. (2008); Yu et al. (2007).

Experimental top

The Schiff base ligand was synthesized by condensation 1,2-diaminopropane and 2-hydroxy-3-ethoxybenzaldehyde with molar ratio 1:2 in ethanol. The mixture formed was allowed to partially evaporate in air for sevral days to produce crystals suitable for X-ray diffraction with a yield about 65%.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); 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 with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

6,6'-Diethoxy-2,2'-[propane-1,2-diylbis(nitrilomethylidyne)]diphenol top

Crystal data top

C₂₁H₂₆N₂O₄	Z = 2
M_r = 370.44	F(000) = 396
Triclinic, P1	D_x = 1.238 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.140 (3) Å	Cell parameters from 1361 reflections
b = 11.451 (4) Å	θ = 2.4–23.9°
c = 13.013 (5) Å	µ = 0.09 mm⁻¹
α = 113.845 (5)°	T = 273 K
β = 109.628 (6)°	Block, yellow
γ = 108.812 (5)°	0.12 × 0.11 × 0.09 mm
V = 993.5 (6) Å³

Data collection top

Bruker APEXII CCD area-detector diffractometer	3451 independent reflections
Radiation source: fine-focus sealed tube	2325 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.030
ϕ and ω scans	θ_max = 25.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
T_min = 0.990, T_max = 0.992	k = −13→11
4894 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)] = 0.066	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.193	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.1202P)²] where P = (F_o² + 2F_c²)/3
3451 reflections	(Δ/σ)_max < 0.001
249 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₂₁H₂₆N₂O₄	γ = 108.812 (5)°
M_r = 370.44	V = 993.5 (6) Å³
Triclinic, P1	Z = 2
a = 9.140 (3) Å	Mo Kα radiation
b = 11.451 (4) Å	µ = 0.09 mm⁻¹
c = 13.013 (5) Å	T = 273 K
α = 113.845 (5)°	0.12 × 0.11 × 0.09 mm
β = 109.628 (6)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	3451 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2325 reflections with I > 2σ(I)
T_min = 0.990, T_max = 0.992	R_int = 0.030
4894 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.066	0 restraints
wR(F²) = 0.193	H-atom parameters constrained
S = 1.00	Δρ_max = 0.26 e Å⁻³
3451 reflections	Δρ_min = −0.26 e Å⁻³
249 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
O1	0.2732 (2)	0.85334 (19)	0.31097 (15)	0.0615 (5)
H1	0.2881	0.8851	0.3848	0.092*
O2	0.1699 (2)	0.75251 (19)	0.06238 (15)	0.0625 (5)
O3	0.1229 (2)	0.44342 (19)	0.38472 (16)	0.0658 (5)
H3	0.1614	0.5336	0.4307	0.099*
O4	0.0549 (2)	0.16836 (19)	0.25933 (17)	0.0666 (5)
N1	0.1898 (3)	0.8527 (2)	0.4813 (2)	0.0553 (5)
N2	0.3270 (3)	0.7183 (2)	0.60118 (19)	0.0571 (5)
C1	−0.0337 (3)	0.6987 (3)	0.2479 (2)	0.0521 (6)
C2	0.0950 (3)	0.7499 (2)	0.2166 (2)	0.0477 (6)
C3	0.0365 (3)	0.6931 (3)	0.0830 (2)	0.0514 (6)
C4	−0.1454 (3)	0.5848 (3)	−0.0147 (3)	0.0621 (7)
H4	−0.1842	0.5446	−0.1036	0.075*
C5	−0.2713 (4)	0.5348 (3)	0.0171 (3)	0.0717 (8)
H5	−0.3937	0.4618	−0.0504	0.086*
C6	−0.2174 (3)	0.5916 (3)	0.1466 (3)	0.0673 (7)
H6	−0.3033	0.5588	0.1674	0.081*
C7	0.0251 (4)	0.7553 (3)	0.3859 (3)	0.0554 (6)
H7	−0.0619	0.7182	0.4045	0.067*
C8	0.1151 (4)	0.6978 (3)	−0.0732 (2)	0.0642 (7)
H8A	0.0269	0.7214	−0.1103	0.077*
H8B	0.0583	0.5892	−0.1270	0.077*
C9	0.2824 (4)	0.7724 (3)	−0.0729 (3)	0.0811 (9)
H9A	0.3376	0.8797	−0.0192	0.122*
H9B	0.2492	0.7382	−0.1626	0.122*
H9C	0.3681	0.7475	−0.0369	0.122*
C10	0.3713 (3)	0.5196 (3)	0.5889 (2)	0.0523 (6)
C11	0.2296 (3)	0.4113 (3)	0.4549 (2)	0.0509 (6)
C12	0.1958 (3)	0.2656 (3)	0.3898 (2)	0.0543 (6)
C13	0.3036 (4)	0.2294 (3)	0.4590 (3)	0.0641 (7)
H13	0.2816	0.1324	0.4161	0.077*
C14	0.4442 (4)	0.3374 (3)	0.5920 (3)	0.0722 (8)
H14	0.5158	0.3124	0.6379	0.087*
C15	0.4778 (4)	0.4803 (3)	0.6557 (3)	0.0687 (7)
H15	0.5728	0.5520	0.7446	0.082*
C16	0.4133 (3)	0.6729 (3)	0.6564 (2)	0.0563 (6)
H16	0.5092	0.7418	0.7454	0.068*
C17	0.0096 (4)	0.0166 (3)	0.1890 (3)	0.0718 (8)
H17A	−0.0139	−0.0273	0.2360	0.086*
H17B	0.1100	0.0128	0.1810	0.086*
C18	−0.1577 (5)	−0.0678 (3)	0.0545 (3)	0.0911 (10)
H18A	−0.2550	−0.0608	0.0637	0.137*
H18B	−0.1943	−0.1717	0.0050	0.137*
H18C	−0.1316	−0.0253	0.0079	0.137*
C19	0.3894 (4)	0.8780 (3)	0.6768 (2)	0.0609 (7)
H19A	0.4958	0.9345	0.6779	0.073*
H19B	0.4262	0.9145	0.7681	0.073*
C20	0.2425 (4)	0.9054 (3)	0.6181 (2)	0.0606 (7)
H20	0.1354	0.8498	0.6181	0.073*
C21	0.3133 (5)	1.0728 (3)	0.6992 (3)	0.0823 (9)
H21A	0.4190	1.1274	0.7001	0.123*
H21B	0.3464	1.1076	0.7889	0.123*
H21C	0.2192	1.0891	0.6599	0.123*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0559 (10)	0.0630 (11)	0.0471 (9)	0.0206 (9)	0.0246 (9)	0.0290 (9)
O2	0.0652 (11)	0.0655 (11)	0.0460 (9)	0.0286 (9)	0.0262 (8)	0.0316 (9)
O3	0.0776 (12)	0.0552 (11)	0.0516 (10)	0.0405 (10)	0.0184 (9)	0.0305 (9)
O4	0.0835 (12)	0.0521 (10)	0.0561 (11)	0.0391 (10)	0.0296 (10)	0.0292 (9)
N1	0.0655 (13)	0.0568 (12)	0.0575 (12)	0.0359 (11)	0.0376 (11)	0.0371 (11)
N2	0.0645 (12)	0.0497 (12)	0.0481 (12)	0.0273 (10)	0.0254 (10)	0.0279 (10)
C1	0.0525 (13)	0.0543 (14)	0.0617 (15)	0.0350 (12)	0.0305 (12)	0.0374 (13)
C2	0.0481 (13)	0.0457 (13)	0.0480 (13)	0.0267 (11)	0.0205 (11)	0.0290 (11)
C3	0.0581 (14)	0.0496 (14)	0.0507 (14)	0.0336 (12)	0.0263 (12)	0.0305 (12)
C4	0.0612 (16)	0.0656 (17)	0.0531 (15)	0.0383 (14)	0.0199 (13)	0.0346 (13)
C5	0.0499 (15)	0.0744 (19)	0.0703 (19)	0.0333 (14)	0.0175 (14)	0.0382 (16)
C6	0.0514 (15)	0.0750 (18)	0.0800 (19)	0.0363 (14)	0.0324 (15)	0.0483 (16)
C7	0.0610 (15)	0.0584 (15)	0.0669 (16)	0.0367 (13)	0.0408 (14)	0.0419 (14)
C8	0.0781 (17)	0.0652 (16)	0.0425 (13)	0.0379 (14)	0.0274 (13)	0.0302 (13)
C9	0.095 (2)	0.085 (2)	0.0584 (17)	0.0396 (18)	0.0421 (16)	0.0423 (16)
C10	0.0522 (13)	0.0598 (15)	0.0498 (13)	0.0284 (12)	0.0264 (12)	0.0370 (12)
C11	0.0558 (13)	0.0574 (15)	0.0537 (14)	0.0337 (12)	0.0300 (12)	0.0394 (12)
C12	0.0609 (15)	0.0575 (15)	0.0559 (15)	0.0335 (13)	0.0342 (13)	0.0372 (13)
C13	0.0728 (17)	0.0681 (17)	0.0798 (19)	0.0450 (15)	0.0460 (16)	0.0538 (16)
C14	0.0699 (17)	0.083 (2)	0.083 (2)	0.0471 (16)	0.0342 (16)	0.0630 (18)
C15	0.0634 (16)	0.0759 (19)	0.0646 (16)	0.0350 (15)	0.0245 (14)	0.0484 (15)
C16	0.0538 (14)	0.0562 (15)	0.0439 (13)	0.0209 (12)	0.0201 (12)	0.0291 (12)
C17	0.0860 (19)	0.0567 (17)	0.079 (2)	0.0429 (16)	0.0472 (17)	0.0374 (15)
C18	0.106 (2)	0.0601 (18)	0.080 (2)	0.0436 (18)	0.041 (2)	0.0271 (17)
C19	0.0686 (15)	0.0513 (15)	0.0475 (14)	0.0251 (13)	0.0255 (12)	0.0271 (12)
C20	0.0739 (17)	0.0623 (16)	0.0578 (15)	0.0367 (14)	0.0445 (14)	0.0359 (13)
C21	0.114 (2)	0.0701 (19)	0.081 (2)	0.0571 (19)	0.063 (2)	0.0424 (17)

Geometric parameters (Å, º) top

O1—C2	1.341 (3)	C9—H9B	0.9600
O1—H1	0.8200	C9—H9C	0.9600
O2—C3	1.361 (3)	C10—C15	1.391 (3)
O2—C8	1.437 (3)	C10—C11	1.397 (3)
O3—C11	1.351 (3)	C10—C16	1.447 (3)
O3—H3	0.8200	C11—C12	1.394 (3)
O4—C12	1.364 (3)	C12—C13	1.387 (4)
O4—C17	1.423 (3)	C13—C14	1.388 (4)
N1—C7	1.262 (3)	C13—H13	0.9300
N1—C20	1.461 (3)	C14—C15	1.366 (4)
N2—C16	1.263 (3)	C14—H14	0.9300
N2—C19	1.461 (3)	C15—H15	0.9300
C1—C6	1.393 (3)	C16—H16	0.9300
C1—C2	1.401 (3)	C17—C18	1.489 (4)
C1—C7	1.456 (4)	C17—H17A	0.9700
C2—C3	1.404 (3)	C17—H17B	0.9700
C3—C4	1.376 (3)	C18—H18A	0.9600
C4—C5	1.382 (4)	C18—H18B	0.9600
C4—H4	0.9300	C18—H18C	0.9600
C5—C6	1.362 (4)	C19—C20	1.503 (4)
C5—H5	0.9300	C19—H19A	0.9700
C6—H6	0.9300	C19—H19B	0.9700
C7—H7	0.9300	C20—C21	1.521 (4)
C8—C9	1.490 (4)	C20—H20	0.9800
C8—H8A	0.9700	C21—H21A	0.9600
C8—H8B	0.9700	C21—H21B	0.9600
C9—H9A	0.9600	C21—H21C	0.9600

C2—O1—H1	109.5	O4—C12—C13	124.9 (2)
C3—O2—C8	116.92 (19)	O4—C12—C11	115.6 (2)
C11—O3—H3	109.5	C13—C12—C11	119.5 (2)
C12—O4—C17	118.2 (2)	C12—C13—C14	120.2 (3)
C7—N1—C20	120.5 (2)	C12—C13—H13	119.9
C16—N2—C19	118.7 (2)	C14—C13—H13	119.9
C6—C1—C2	119.9 (2)	C15—C14—C13	120.3 (2)
C6—C1—C7	120.0 (2)	C15—C14—H14	119.9
C2—C1—C7	120.1 (2)	C13—C14—H14	119.9
O1—C2—C1	122.0 (2)	C14—C15—C10	120.7 (3)
O1—C2—C3	118.7 (2)	C14—C15—H15	119.6
C1—C2—C3	119.4 (2)	C10—C15—H15	119.6
O2—C3—C4	125.7 (2)	N2—C16—C10	123.6 (2)
O2—C3—C2	115.3 (2)	N2—C16—H16	118.2
C4—C3—C2	119.1 (2)	C10—C16—H16	118.2
C3—C4—C5	121.1 (2)	O4—C17—C18	107.3 (2)
C3—C4—H4	119.4	O4—C17—H17A	110.3
C5—C4—H4	119.4	C18—C17—H17A	110.3
C6—C5—C4	120.5 (2)	O4—C17—H17B	110.3
C6—C5—H5	119.8	C18—C17—H17B	110.3
C4—C5—H5	119.8	H17A—C17—H17B	108.5
C5—C6—C1	120.0 (3)	C17—C18—H18A	109.5
C5—C6—H6	120.0	C17—C18—H18B	109.5
C1—C6—H6	120.0	H18A—C18—H18B	109.5
N1—C7—C1	122.4 (2)	C17—C18—H18C	109.5
N1—C7—H7	118.8	H18A—C18—H18C	109.5
C1—C7—H7	118.8	H18B—C18—H18C	109.5
O2—C8—C9	107.9 (2)	N2—C19—C20	112.0 (2)
O2—C8—H8A	110.1	N2—C19—H19A	109.2
C9—C8—H8A	110.1	C20—C19—H19A	109.2
O2—C8—H8B	110.1	N2—C19—H19B	109.2
C9—C8—H8B	110.1	C20—C19—H19B	109.2
H8A—C8—H8B	108.4	H19A—C19—H19B	107.9
C8—C9—H9A	109.5	N1—C20—C19	109.1 (2)
C8—C9—H9B	109.5	N1—C20—C21	109.2 (2)
H9A—C9—H9B	109.5	C19—C20—C21	110.2 (2)
C8—C9—H9C	109.5	N1—C20—H20	109.5
H9A—C9—H9C	109.5	C19—C20—H20	109.5
H9B—C9—H9C	109.5	C21—C20—H20	109.5
C15—C10—C11	119.3 (2)	C20—C21—H21A	109.5
C15—C10—C16	119.9 (2)	C20—C21—H21B	109.5
C11—C10—C16	120.8 (2)	H21A—C21—H21B	109.5
O3—C11—C12	118.1 (2)	C20—C21—H21C	109.5
O3—C11—C10	121.8 (2)	H21A—C21—H21C	109.5
C12—C11—C10	120.0 (2)	H21B—C21—H21C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···N2	0.82	1.89	2.614 (3)	147
O1—H1···N1	0.82	1.85	2.576 (2)	146

Experimental details

Crystal data
Chemical formula	C₂₁H₂₆N₂O₄
M_r	370.44
Crystal system, space group	Triclinic, P1
Temperature (K)	273
a, b, c (Å)	9.140 (3), 11.451 (4), 13.013 (5)
α, β, γ (°)	113.845 (5), 109.628 (6), 108.812 (5)
V (Å³)	993.5 (6)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.12 × 0.11 × 0.09

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.990, 0.992
No. of measured, independent and observed [I > 2σ(I)] reflections	4894, 3451, 2325
R_int	0.030
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.066, 0.193, 1.00
No. of reflections	3451
No. of parameters	249
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.26

Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2001), 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
O3—H3···N2	0.82	1.89	2.614 (3)	146.7
O1—H1···N1	0.82	1.85	2.576 (2)	146.2

References

Bermejo, M. R., Fernandez, M. I., Gomez-forneas, E., Gonzalez-noya, A., Maneiro, M., Pedrido, R. & Rodringuez, M. J. (2007). Eur. J. Inorg. Chem. pp. 3104–3112. Google Scholar
Bruker (2001). SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Mohanta, S., Lin, H. H., Lee, C. J. & Wei, H. H. (2002). Inorg. Chem. Commun. 5, 585–588. Web of Science CSD CrossRef CAS Google Scholar
Nayak, M., Koner, R., Lin, H. H., Florke, U., Wei, H. H. & Mohanta, S. (2006). Inorg. Chem. 45, 10764–10773. Web of Science CSD CrossRef PubMed CAS Google Scholar
Ni, Z. H., Kou, H. Z., Zhang, L. F., Ge, C. H., Cui, A. L., Wang, R. J., Li, Y. D. & Sato, O. (2005). Angew. Chem. Int. Ed. 44, 7742–7745. Web of Science CSD CrossRef CAS Google Scholar
Saha, P. K., Dutta, B., Jana, S., Bera, R., Saha, S., Okamoto, K. & Koner, S. (2007). Polyhedron, 26, 563–571. Web of Science CSD CrossRef CAS 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, H., Zhang, D., Tian, L. & Zhang, L.-F. (2008). Acta Cryst. E64, m1460. Web of Science CSD CrossRef IUCr Journals Google Scholar
Yu, T. Z., Zhang, K., Zhao, Y. L., Yang, C. H., Zhang, H., Fan, D. W. & Dong, W. K. (2007). Inorg. Chem. Commun. 10, 401–403. Web of Science CSD CrossRef CAS Google Scholar

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Volume 65| Part 3| March 2009| Page o646

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