Bis[2-meth­oxy-6-(3-pyridylmethyl­imino­meth­yl)phenolato-κ2N,O]copper(II)

Chen, X.; Sun, Y.; Yao, Q.; Zhang, H.; Liang, Q.

doi:10.1107/S1600536809052349

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 1| January 2010| Page m39

doi:10.1107/S1600536809052349

Open

access

Bis[2-methoxy-6-(3-pyridylmethyliminomethyl)phenolato-κ²N,O]copper(II)

Xiaodan Chen,^a Yu Sun,^b Qingzhao Yao,^a ^* Huaihong Zhang ^a and Qing Liang ^a

^aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096, People's Republic of China, and ^bCollege of Pharmacy, Jiangsu University, Zhenjiang 212013, People's Republic of China
^*Correspondence e-mail: chmsunbw@seu.edu.cn

(Received 13 November 2009; accepted 5 December 2009; online 12 December 2009)

In the title complex, [Cu(C₁₄H₁₃N₂O₂)₂], the Cu^II ion is located on a crystallographic inversion center. The complex thus adopts a square-planar trans-[CuN₂O₂] coordination geometry, with the Cu^II ion coordinated by two 2-methoxy-6-(3-pyridylmethyliminomethyl)phenolate (Schiff base) ligands. The aryl and pyridyl rings in the Schiff base are almost perpendicular to each other, with a dihedral angle of 87.61 (6)° between the planes of the two six-membered rings. The pyridyl ring was refined using a disorder model with approximately 70% occupancy for the major component

Related literature

For recent developments in functional switching materials, see: Sato et al. (2003 ). Bis-(N-alkysalicylideneimine)copper(II) complexes for induced structural phase transitions, see: Yamada (1999 ), and the structural isomers can be isolated, see: Chia et al. (1997 ). For related metal complexes containing Schiff bases, see: You & Zhu (2004 ).

Experimental

Crystal data

[Cu(C₁₄H₁₃N₂O₂)₂]
M_r = 546.07
Triclinic, $[P \overline 1]$
a = 5.175 (1) Å
b = 10.7291 (14) Å
c = 11.4369 (15) Å
α = 99.689 (1)°
β = 91.361 (1)°
γ = 103.241 (2)°
V = 608.03 (16) Å³
Z = 1
Mo Kα radiation
μ = 0.94 mm⁻¹
T = 298 K
0.47 × 0.40 × 0.29 mm

Data collection

Siemens SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.666, T_max = 0.772
3054 measured reflections
2101 independent reflections
1908 reflections with I > 2σ(I)
R_int = 0.021

Refinement

R[F² > 2σ(F²)] = 0.037
wR(F²) = 0.094
S = 1.09
2101 reflections
171 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Cu1—O1	1.9005 (18)
Cu1—N1	1.997 (2)

O1—Cu1—N1	91.31 (8)

Data collection: SMART (Siemens, 1996 ); cell refinement: SAINT (Siemens, 1996); 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 I, global. DOI: 10.1107/S1600536809052349/nk2015sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809052349/nk2015Isup2.hkl

checkCIF report

Comment top

Recent developments in functional switching materials (Sato et al., 2003) have shown that a good way to discover candidate metal complexes is to examine compounds that show any changes between two or more states, such as structural phase transitions, isomerism, mixed valences and spin-crossover. In this respect, bis-(N-alkysalicylideneimine)copper(II) complexes have potential for induced structural phase transitions (Yamada, 1999) and the structural isomers can be isolated (Chia et al., 1997).

Herein, we reported a new crystal strucure of the title compound (I). The stucture of (I) is shown in Fig.1. It can be clearly seen that this compound possesses a slightly distorted square-planar trans-[CuN₂O₂] coordination geomentry with the Cu^II ion located on a crystallographic inversion center. In addition, the phenyl ring is almost on the same plane with the [CuN₂O₂] square plane with a dihedral angle of approximately 6.293° between the two planes, while the pyridyl ring is nearly vertical with the [CuN₂O₂] square plane with a dihedral angle of approximately 83.12°. The pyridyl ring was refined using a two-part disorder model, interchanging the positions of N2 and C13 with approximately 70% occupancy for the major component; this conformation is the most likely according to the ring geometry and the surrounding environment.

Related literature top

For recent developments in functional switching materials, see: Sato et al. (2003). Bis-(N-alkysalicylideneimine)copper(II) complexes for induced structural phase transitions, see: Yamada (1999), and the structural isomers can be isolated, see: Chia et al. (1997). For related literature, see: You & Zhu (2004).

Experimental top

The title compound was synthesized by Cu(NO₃)₂.3H₂O and Schiff base ligand 2-methoxy-6-[(pyridin-3-ylmethylimino)-methyl]-phenol. All chemicals used (reagent grade) were commercially available. 2-Hydroxy-3-methoxy-benzaldehyde(0.108 g, 1 mmol) was dissolved in ethanol (5 mL) and ethanol solution (5 ml) containing 2-aminoethylpyri dine (0.152 g, 1 mmol) was added slowly with stirring. The resulting yellow solution was continuously stirred for about 30 min. at room temperature, and then Cu(NO₃)₂.3H₂O (0.241 g, 1 mmol) in aqueous solution (5 ml) was added with stirring at room temperature. Brown crystals suitable for X-ray analysis were obtained by slow evaporation at room temperature over several days.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); 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. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.All hydrogen atoms and the minor disorder component are omitted for clarity. [Symmetry code A: -x + 1, -y + 1, -z + 1]

Bis[2-methoxy-6-(3-pyridylmethyliminomethyl)phenolato- κ²N,O]copper(II) top

Crystal data top

[Cu(C₁₄H₁₃N₂O₂)₂]	Z = 1
M_r = 546.07	F(000) = 283
Triclinic, P1	D_x = 1.491 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.175 (1) Å	Cell parameters from 13380 reflections
b = 10.7291 (14) Å	θ = 3.0–25.0°
c = 11.4369 (15) Å	µ = 0.94 mm⁻¹
α = 99.689 (1)°	T = 298 K
β = 91.361 (1)°	Prism, brown
γ = 103.241 (2)°	0.47 × 0.40 × 0.29 mm
V = 608.03 (16) Å³

Data collection top

Siemens SMART CCD area-detector diffractometer	2101 independent reflections
Radiation source: sealed tube	1908 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.021
Detector resolution: 8.192 pixels mm^-1	θ_max = 25.0°, θ_min = 1.8°
Thin–slice ω scans	h = −5→6
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −11→12
T_min = 0.666, T_max = 0.772	l = −13→13
3054 measured reflections

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.094	H-atom parameters constrained
S = 1.09	w = 1/[σ²(F_o²) + (0.0374P)² + 0.3354P] where P = (F_o² + 2F_c²)/3
2101 reflections	(Δ/σ)_max < 0.001
171 parameters	Δρ_max = 0.23 e Å⁻³
0 restraints	Δρ_min = −0.40 e Å⁻³

Crystal data top

[Cu(C₁₄H₁₃N₂O₂)₂]	γ = 103.241 (2)°
M_r = 546.07	V = 608.03 (16) Å³
Triclinic, P1	Z = 1
a = 5.175 (1) Å	Mo Kα radiation
b = 10.7291 (14) Å	µ = 0.94 mm⁻¹
c = 11.4369 (15) Å	T = 298 K
α = 99.689 (1)°	0.47 × 0.40 × 0.29 mm
β = 91.361 (1)°

Data collection top

Siemens SMART CCD area-detector diffractometer	2101 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1908 reflections with I > 2σ(I)
T_min = 0.666, T_max = 0.772	R_int = 0.021
3054 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.037	0 restraints
wR(F²) = 0.094	H-atom parameters constrained
S = 1.09	Δρ_max = 0.23 e Å⁻³
2101 reflections	Δρ_min = −0.40 e Å⁻³
171 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	0.5000	0.5000	0.5000	0.03467 (17)
N1	0.5603 (4)	0.3229 (2)	0.44427 (19)	0.0374 (5)
C1	0.4647 (5)	0.2520 (3)	0.3428 (2)	0.0396 (6)
H1	0.5277	0.1775	0.3201	0.048*
C2	0.2735 (5)	0.2746 (3)	0.2613 (2)	0.0386 (6)
C3	0.1569 (5)	0.3815 (3)	0.2862 (2)	0.0352 (6)
C4	−0.0381 (5)	0.3930 (3)	0.2004 (2)	0.0405 (6)
C5	−0.0989 (6)	0.3047 (3)	0.0952 (3)	0.0501 (8)
H5	−0.2233	0.3144	0.0395	0.060*
C6	0.0245 (6)	0.2009 (3)	0.0715 (3)	0.0549 (8)
H6	−0.0175	0.1423	0.0002	0.066*
C7	0.2054 (6)	0.1856 (3)	0.1523 (3)	0.0503 (7)
H7	0.2857	0.1160	0.1362	0.060*
C8	−0.3148 (6)	0.5261 (4)	0.1431 (3)	0.0615 (9)
H8A	−0.2139	0.5422	0.0755	0.092*
H8B	−0.3757	0.6021	0.1751	0.092*
H8C	−0.4650	0.4540	0.1191	0.092*
C9	0.7366 (6)	0.2684 (3)	0.5141 (2)	0.0413 (6)
H9A	0.8854	0.3376	0.5512	0.050*
H9B	0.8068	0.2052	0.4614	0.050*
C10	0.7083 (8)	0.2181 (3)	0.7196 (3)	0.0675 (10)
H10	0.8760	0.2743	0.7354	0.081*
C11	0.5900 (5)	0.2036 (2)	0.6089 (2)	0.0386 (6)
C12	0.3393 (7)	0.1225 (4)	0.5890 (3)	0.0689 (10)
H12	0.2480	0.1087	0.5151	0.083*
N2	0.6057 (10)	0.1590 (4)	0.8074 (3)	0.0946 (16)	0.70 (4)
C13	0.2220 (8)	0.0611 (4)	0.6786 (5)	0.0910 (17)	0.70 (4)
H13A	0.0530	0.0057	0.6658	0.109*	0.70 (4)
N2'	0.2220 (8)	0.0611 (4)	0.6786 (5)	0.0910 (17)	0.30 (4)
C13'	0.6057 (10)	0.1590 (4)	0.8074 (3)	0.0946 (16)	0.30 (4)
H13B	0.6924	0.1680	0.8736	0.113*	0.30 (4)
C14	0.3650 (12)	0.0834 (5)	0.7849 (4)	0.0863 (14)
H14	0.2856	0.0419	0.8446	0.104*
O1	0.2170 (4)	0.47043 (18)	0.38216 (16)	0.0423 (5)
O2	−0.1501 (4)	0.4964 (2)	0.23188 (18)	0.0514 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0353 (3)	0.0383 (3)	0.0307 (3)	0.00863 (19)	−0.00441 (18)	0.00810 (19)
N1	0.0374 (12)	0.0430 (13)	0.0360 (12)	0.0136 (10)	0.0011 (9)	0.0134 (10)
C1	0.0449 (16)	0.0396 (15)	0.0368 (15)	0.0137 (12)	0.0045 (12)	0.0083 (12)
C2	0.0395 (15)	0.0416 (15)	0.0320 (14)	0.0029 (12)	0.0028 (11)	0.0080 (11)
C3	0.0314 (14)	0.0420 (15)	0.0303 (14)	0.0018 (11)	−0.0006 (10)	0.0107 (11)
C4	0.0332 (14)	0.0480 (16)	0.0386 (15)	0.0008 (12)	−0.0024 (11)	0.0152 (13)
C5	0.0418 (17)	0.068 (2)	0.0350 (15)	−0.0004 (15)	−0.0078 (12)	0.0134 (14)
C6	0.057 (2)	0.065 (2)	0.0332 (16)	0.0014 (16)	−0.0042 (14)	−0.0019 (14)
C7	0.0575 (19)	0.0477 (17)	0.0406 (16)	0.0074 (14)	0.0005 (14)	0.0011 (13)
C8	0.0455 (18)	0.080 (2)	0.065 (2)	0.0112 (16)	−0.0111 (15)	0.0360 (18)
C9	0.0396 (16)	0.0445 (15)	0.0444 (16)	0.0183 (12)	−0.0024 (12)	0.0100 (12)
C10	0.081 (3)	0.063 (2)	0.048 (2)	−0.0061 (19)	−0.0108 (17)	0.0142 (17)
C11	0.0462 (16)	0.0346 (14)	0.0396 (15)	0.0188 (12)	−0.0011 (12)	0.0075 (11)
C12	0.054 (2)	0.087 (3)	0.067 (2)	0.0038 (19)	−0.0113 (17)	0.036 (2)
N2	0.138 (4)	0.090 (3)	0.049 (2)	0.004 (3)	0.003 (2)	0.0261 (19)
C13	0.063 (3)	0.084 (3)	0.140 (5)	0.015 (2)	0.026 (3)	0.058 (3)
N2'	0.063 (3)	0.084 (3)	0.140 (5)	0.015 (2)	0.026 (3)	0.058 (3)
C13'	0.138 (4)	0.090 (3)	0.049 (2)	0.004 (3)	0.003 (2)	0.0261 (19)
C14	0.125 (4)	0.081 (3)	0.080 (3)	0.052 (3)	0.049 (3)	0.046 (3)
O1	0.0422 (11)	0.0475 (11)	0.0375 (10)	0.0166 (9)	−0.0117 (8)	0.0017 (9)
O2	0.0450 (12)	0.0587 (13)	0.0516 (12)	0.0133 (10)	−0.0159 (9)	0.0141 (10)

Geometric parameters (Å, º) top

Cu1—O1	1.9005 (18)	C8—O2	1.432 (3)
Cu1—O1ⁱ	1.9005 (18)	C8—H8A	0.9600
Cu1—N1ⁱ	1.997 (2)	C8—H8B	0.9600
Cu1—N1	1.997 (2)	C8—H8C	0.9600
N1—C1	1.294 (3)	C9—C11	1.512 (4)
N1—C9	1.476 (3)	C9—H9A	0.9700
C1—C2	1.432 (4)	C9—H9B	0.9700
C1—H1	0.9300	C10—N2	1.333 (5)
C2—C3	1.406 (4)	C10—C11	1.362 (4)
C2—C7	1.418 (4)	C10—H10	0.9300
C3—O1	1.306 (3)	C11—C12	1.377 (4)
C3—C4	1.431 (4)	C12—C13	1.389 (5)
C4—O2	1.366 (3)	C12—H12	0.9301
C4—C5	1.381 (4)	N2—C14	1.314 (7)
C5—C6	1.397 (4)	N2—H13B	0.8506
C5—H5	0.9300	C13—C14	1.364 (7)
C6—C7	1.356 (4)	C13—H13A	0.9305
C6—H6	0.9300	C14—H14	0.9300
C7—H7	0.9300

O1—Cu1—O1ⁱ	180.000 (1)	O2—C8—H8B	109.5
O1—Cu1—N1ⁱ	88.69 (8)	H8A—C8—H8B	109.5
O1ⁱ—Cu1—N1ⁱ	91.31 (8)	O2—C8—H8C	109.5
O1—Cu1—N1	91.31 (8)	H8A—C8—H8C	109.5
O1ⁱ—Cu1—N1	88.69 (8)	H8B—C8—H8C	109.5
N1ⁱ—Cu1—N1	180.000 (1)	N1—C9—C11	111.4 (2)
C1—N1—C9	115.3 (2)	N1—C9—H9A	109.3
C1—N1—Cu1	123.32 (19)	C11—C9—H9A	109.3
C9—N1—Cu1	121.18 (18)	N1—C9—H9B	109.3
N1—C1—C2	127.6 (3)	C11—C9—H9B	109.3
N1—C1—H1	116.2	H9A—C9—H9B	108.0
C2—C1—H1	116.2	N2—C10—C11	125.9 (4)
C3—C2—C7	120.3 (3)	N2—C10—H10	117.1
C3—C2—C1	121.9 (2)	C11—C10—H10	117.0
C7—C2—C1	117.8 (3)	C10—C11—C12	115.8 (3)
O1—C3—C2	124.0 (2)	C10—C11—C9	120.7 (3)
O1—C3—C4	118.5 (2)	C12—C11—C9	123.4 (3)
C2—C3—C4	117.5 (2)	C11—C12—C13	120.2 (4)
O2—C4—C5	124.9 (3)	C11—C12—H12	119.9
O2—C4—C3	114.6 (2)	C13—C12—H12	119.8
C5—C4—C3	120.5 (3)	C14—N2—C10	116.2 (4)
C4—C5—C6	120.7 (3)	C14—N2—H13B	121.7
C4—C5—H5	119.6	C10—N2—H13B	122.0
C6—C5—H5	119.6	C14—C13—C12	117.6 (4)
C7—C6—C5	120.1 (3)	C14—C13—H13A	121.5
C7—C6—H6	119.9	C12—C13—H13A	120.9
C5—C6—H6	119.9	N2—C14—C13	124.1 (4)
C6—C7—C2	120.8 (3)	N2—C14—H14	118.6
C6—C7—H7	119.6	C13—C14—H14	117.3
C2—C7—H7	119.6	C3—O1—Cu1	129.26 (17)
O2—C8—H8A	109.5	C4—O2—C8	117.5 (2)

O1—Cu1—N1—C1	15.6 (2)	C3—C2—C7—C6	−1.0 (4)
O1ⁱ—Cu1—N1—C1	−164.4 (2)	C1—C2—C7—C6	179.6 (3)
N1ⁱ—Cu1—N1—C1	−141 (100)	C1—N1—C9—C11	−99.3 (3)
O1—Cu1—N1—C9	−169.17 (19)	Cu1—N1—C9—C11	85.1 (2)
O1ⁱ—Cu1—N1—C9	10.83 (19)	N2—C10—C11—C12	1.6 (6)
N1ⁱ—Cu1—N1—C9	34 (100)	N2—C10—C11—C9	−175.3 (4)
C9—N1—C1—C2	174.5 (2)	N1—C9—C11—C10	−139.2 (3)
Cu1—N1—C1—C2	−9.9 (4)	N1—C9—C11—C12	44.1 (4)
N1—C1—C2—C3	−1.8 (4)	C10—C11—C12—C13	−0.1 (5)
N1—C1—C2—C7	177.6 (3)	C9—C11—C12—C13	176.7 (3)
C7—C2—C3—O1	−177.1 (2)	C11—C10—N2—C14	−2.3 (7)
C1—C2—C3—O1	2.2 (4)	C11—C12—C13—C14	−0.7 (6)
C7—C2—C3—C4	2.5 (4)	C10—N2—C14—C13	1.4 (7)
C1—C2—C3—C4	−178.1 (2)	C12—C13—C14—N2	0.0 (7)
O1—C3—C4—O2	−2.5 (3)	C2—C3—O1—Cu1	10.5 (4)
C2—C3—C4—O2	177.9 (2)	C4—C3—O1—Cu1	−169.14 (17)
O1—C3—C4—C5	177.0 (2)	O1ⁱ—Cu1—O1—C3	−12 (100)
C2—C3—C4—C5	−2.7 (4)	N1ⁱ—Cu1—O1—C3	163.5 (2)
O2—C4—C5—C6	−179.3 (3)	N1—Cu1—O1—C3	−16.5 (2)
C3—C4—C5—C6	1.3 (4)	C5—C4—O2—C8	−9.1 (4)
C4—C5—C6—C7	0.3 (4)	C3—C4—O2—C8	170.4 (2)
C5—C6—C7—C2	−0.5 (5)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	[Cu(C₁₄H₁₃N₂O₂)₂]
M_r	546.07
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	5.175 (1), 10.7291 (14), 11.4369 (15)
α, β, γ (°)	99.689 (1), 91.361 (1), 103.241 (2)
V (Å³)	608.03 (16)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.94
Crystal size (mm)	0.47 × 0.40 × 0.29

Data collection
Diffractometer	Siemens SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.666, 0.772
No. of measured, independent and observed [I > 2σ(I)] reflections	3054, 2101, 1908
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.037, 0.094, 1.09
No. of reflections	2101
No. of parameters	171
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.40

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top

Cu1—O1	1.9005 (18)	Cu1—N1ⁱ	1.997 (2)
Cu1—O1ⁱ	1.9005 (18)	Cu1—N1	1.997 (2)

O1—Cu1—N1ⁱ	88.69 (8)	O1—Cu1—N1	91.31 (8)
O1ⁱ—Cu1—N1ⁱ	91.31 (8)	O1ⁱ—Cu1—N1	88.69 (8)

Symmetry code: (i) −x+1, −y+1, −z+1.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Project 20671019)

References

Chia, P. C., Freyberg, D. P., Mockler, G. M. & Sinn, E. (1997). Inorg. Chem. 16, 254–264. CSD CrossRef Web of Science Google Scholar
Sato, O., Hayami, S., Einaga, Y. & Gu, Z. (2003). Bull. Chem. Soc. Jpn, 76, 443–470. 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
Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Yamada, S. (1999). Coord. Chem. Rev. 190–192, 537–555. CrossRef CAS Google Scholar
You, Z.-L. & Zhu, H.-L. (2004). Z. Anorg. Allg. Chem. 630, 2754–2760. Web of Science CSD CrossRef CAS Google Scholar