Bis(2-ethyl-1H-imidazole-κN3)bis­(nitrito-κ2O,O′)copper(II) dihydrate

Zhu, R.-Q.

doi:10.1107/S1600536811022367

metal-organic compounds

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Volume 67| Part 7| July 2011| Page m937

doi:10.1107/S1600536811022367

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Bis(2-ethyl-1H-imidazole-κN³)bis(nitrito-κ²O,O′)copper(II) dihydrate

Run-Qiang Zhu ^a ^*

^aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
^*Correspondence e-mail: zhurunqiang@163.com

(Received 14 May 2011; accepted 9 June 2011; online 18 June 2011)

In the title compound, [Cu(NO₂)₂(C₅H₈N₂)]·2H₂O, the Cu²⁺ ion exhibits site symmetry 2 and is hexacoordinated by four O atoms from two nitrite ions and two N atoms from two 2-ethyl-1H-imidazole molecules. A free water molecule assists in forming a three-dimensional network holding together the complexes via O—H⋯N, O—H⋯O and N—H⋯O hydrogen bonds.

Related literature

For general background on ferroelectric compounds with metal–organic framework structures, see: Fu et al. (2009 ); Ye et al. (2006 ); Zhang et al. (2008 , 2010 ). For graph-set motifs of hydrogen bonds, see: Bernstein et al. (1995 ).

Experimental

Crystal data

[Cu(NO₂)₂(C₅H₈N₂)]·2H₂O
M_r = 383.86
Orthorhombic, P b c n
a = 12.960 (6) Å
b = 17.635 (7) Å
c = 7.288 (3) Å
V = 1665.7 (12) Å³
Z = 4
Mo Kα radiation
μ = 1.35 mm⁻¹
T = 293 K
0.30 × 0.25 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ) T_min = 0.674, T_max = 0.763
16649 measured reflections
1902 independent reflections
1712 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.079
S = 1.10
1902 reflections
113 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Table 1
Selected bond lengths (Å)

Cu1—N1	1.9752 (17)
Cu1—O6	2.0255 (15)
Cu1—O5	2.4501 (18)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2B⋯O7	0.86	1.99	2.830 (3)	167
O7—H1⋯O6ⁱⁱ	0.84 (1)	2.05 (2)	2.862 (2)	163 (3)
O7—H2⋯N3ⁱⁱⁱ	0.83 (1)	2.18 (1)	3.004 (3)	167 (3)
Symmetry codes: (ii) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, z]$ ; (iii) $[-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811022367/vn2010sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811022367/vn2010Isup2.hkl

checkCIF report

Comment top

We synthesized the title compound with the aim to find new ferroelectric materials (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). For the title compound no dielectric anomalies were observed in the range from 190 K to near its melting point (m.p. >400 K). A view of the title compound is shown in Fig. 1. The structure is consolidated by multiple intermolecular and intramolecular hydrogen bonds between O and N. This hydrogen bonding (Table 1, Fig. 2) produces a three-dimensional network. Hydrogen bonding is the most reliable design element in the non-covalent assembly of neutral molecules with donor and acceptor functionalities, and as such it is the most important interaction in crystal engineering (Bernstein et al., 1995). The two contact distances between Cu and the oxygens of the nitrate ion are very different (Cu1–O5=2.4501 (18) Å and Cu1–O6=2.0255 (15) Å), showing thus only moderate bonding.

Related literature top

For general background on ferroelectric metal–organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010). For graph-set motifs of hydrogen bonds, see: Bernstein et al. (1995).

Experimental top

An aqueous solution of 2-ethyl imidazole (2.4 g, 25 mmol) and H₂SO₄(12.5 mmol) was treated with CuSO₄ (250 g, 12.5 mmol). After the mixture was churned for a few minutes, Ba(NO₂)₂ (6.18 g, 25 mmol) was added to give a blue solution. Slow evaporation of the solution yielded blue crystals after a few days.

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound, with the displacement ellipsoids drawn at the 30% probability level. The weak Cu—O interactions and the hydrogen bonds are shown as dashed lines. [Symmetry code: (A) - 1-x, y, 1/2-z]
	Fig. 2. A view of the N—H···O, O—H···N and O—H···O interactions (dotted lines) in the crystal structure of the title compound. [Symmetry codes: (i)-x + 3/2, y - 1/2, z (ii)-x + 3/2, -y + 1/2, z + 1/2]

Bis(2-ethyl-1H-imidazole-κN³)bis(nitrito- κ²O,O')copper(II) dihydrate top

Crystal data top

[Cu(NO₂)₂(C₅H₈N₂)]·2H₂O	F(000) = 796
M_r = 383.86	D_x = 1.531 Mg m⁻³
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 3875 reflections
a = 12.960 (6) Å	θ = 2.8–27.5°
b = 17.635 (7) Å	µ = 1.35 mm⁻¹
c = 7.288 (3) Å	T = 293 K
V = 1665.7 (12) Å³	Block, blue
Z = 4	0.30 × 0.25 × 0.20 mm

Data collection top

Rigaku, SCXmini diffractometer	1902 independent reflections
Radiation source: fine-focus sealed tube	1712 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
ω scans	θ_max = 27.5°, θ_min = 3.6°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	h = −16→16
T_min = 0.674, T_max = 0.763	k = −22→22
16649 measured reflections	l = −9→9

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.079	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ²(F_o²) + (0.0424P)² + 0.3653P] where P = (F_o² + 2F_c²)/3
1902 reflections	(Δ/σ)_max = 0.001
113 parameters	Δρ_max = 0.33 e Å⁻³
5 restraints	Δρ_min = −0.24 e Å⁻³

Crystal data top

[Cu(NO₂)₂(C₅H₈N₂)]·2H₂O	V = 1665.7 (12) Å³
M_r = 383.86	Z = 4
Orthorhombic, Pbcn	Mo Kα radiation
a = 12.960 (6) Å	µ = 1.35 mm⁻¹
b = 17.635 (7) Å	T = 293 K
c = 7.288 (3) Å	0.30 × 0.25 × 0.20 mm

Data collection top

Rigaku, SCXmini diffractometer	1902 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	1712 reflections with I > 2σ(I)
T_min = 0.674, T_max = 0.763	R_int = 0.032
16649 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	5 restraints
wR(F²) = 0.079	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	Δρ_max = 0.33 e Å⁻³
1902 reflections	Δρ_min = −0.24 e Å⁻³
113 parameters

Special details top

Geometry. All e.s.d.'s 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 and angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry.

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
C1	0.65105 (15)	0.16593 (12)	0.2425 (3)	0.0354 (4)
C2	0.63010 (17)	0.21323 (12)	−0.0306 (3)	0.0429 (5)
H2A	0.6067	0.2436	−0.1262	0.051*
C3	0.69903 (18)	0.15687 (14)	−0.0455 (3)	0.0502 (6)
H3A	0.7321	0.1411	−0.1521	0.060*
C4	0.64560 (18)	0.15017 (13)	0.4424 (3)	0.0451 (5)
H4A	0.6091	0.1914	0.5021	0.054*
H4B	0.7151	0.1488	0.4917	0.054*
C5	0.5918 (2)	0.07583 (15)	0.4881 (4)	0.0637 (7)
H5A	0.5923	0.0683	0.6185	0.096*
H5B	0.6274	0.0347	0.4293	0.096*
H5C	0.5218	0.0776	0.4453	0.096*
N1	0.59959 (13)	0.21864 (9)	0.1508 (2)	0.0342 (4)
N2	0.71115 (13)	0.12722 (11)	0.1257 (3)	0.0465 (4)
H2B	0.7508	0.0899	0.1541	0.056*
Cu1	0.5000	0.292843 (17)	0.2500	0.02994 (13)
O6	0.57539 (11)	0.37719 (8)	0.1173 (2)	0.0460 (4)
O7	0.82902 (14)	0.00761 (11)	0.2776 (3)	0.0563 (5)
O5	0.44637 (13)	0.34927 (11)	−0.0420 (2)	0.0604 (5)
N3	0.52032 (17)	0.39184 (12)	−0.0252 (3)	0.0528 (5)
H1	0.848 (2)	−0.0289 (14)	0.213 (4)	0.088 (12)*
H2	0.8774 (18)	0.0299 (17)	0.330 (5)	0.104 (13)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0307 (9)	0.0311 (10)	0.0443 (11)	−0.0003 (8)	−0.0020 (8)	−0.0012 (8)
C2	0.0446 (12)	0.0477 (12)	0.0364 (11)	0.0071 (9)	0.0052 (9)	0.0002 (9)
C3	0.0488 (12)	0.0564 (14)	0.0455 (13)	0.0086 (10)	0.0094 (10)	−0.0069 (11)
C4	0.0462 (11)	0.0459 (12)	0.0434 (12)	0.0009 (9)	−0.0055 (10)	0.0050 (10)
C5	0.0735 (17)	0.0546 (15)	0.0631 (16)	−0.0072 (13)	0.0031 (14)	0.0163 (12)
N1	0.0349 (8)	0.0324 (8)	0.0352 (9)	0.0022 (6)	0.0032 (7)	0.0002 (7)
N2	0.0405 (9)	0.0434 (10)	0.0557 (12)	0.0136 (8)	0.0012 (9)	−0.0035 (9)
Cu1	0.0318 (2)	0.0253 (2)	0.0327 (2)	0.000	0.00267 (12)	0.000
O6	0.0511 (8)	0.0358 (7)	0.0512 (9)	−0.0066 (6)	0.0063 (7)	0.0036 (7)
O7	0.0532 (10)	0.0438 (10)	0.0720 (12)	0.0097 (8)	−0.0056 (9)	−0.0079 (9)
O5	0.0549 (10)	0.0723 (12)	0.0541 (10)	−0.0012 (9)	−0.0072 (8)	0.0181 (9)
N3	0.0633 (13)	0.0455 (11)	0.0497 (12)	0.0011 (9)	0.0107 (10)	0.0131 (9)

Geometric parameters (Å, º) top

C1—N1	1.325 (3)	C5—H5B	0.9600
C1—N2	1.341 (3)	C5—H5C	0.9600
C1—C4	1.485 (3)	N1—Cu1	1.9752 (17)
C2—C3	1.341 (3)	N2—H2B	0.8600
C2—N1	1.383 (3)	Cu1—N1ⁱ	1.9752 (17)
C2—H2A	0.9300	Cu1—O6	2.0255 (15)
C3—N2	1.362 (3)	Cu1—O6ⁱ	2.0255 (15)
C3—H3A	0.9300	Cu1—O5	2.4501 (18)
C4—C5	1.522 (3)	O6—N3	1.287 (3)
C4—H4A	0.9700	O7—H1	0.835 (11)
C4—H4B	0.9700	O7—H2	0.834 (11)
C5—H5A	0.9600	O5—N3	1.223 (3)

N1—C1—N2	109.23 (18)	C1—N1—C2	106.86 (17)
N1—C1—C4	127.04 (19)	C1—N1—Cu1	127.51 (14)
N2—C1—C4	123.73 (19)	C2—N1—Cu1	125.63 (14)
C3—C2—N1	108.6 (2)	C1—N2—C3	108.61 (18)
C3—C2—H2A	125.7	C1—N2—H2B	125.7
N1—C2—H2A	125.7	C3—N2—H2B	125.7
C2—C3—N2	106.7 (2)	N1ⁱ—Cu1—N1	97.01 (10)
C2—C3—H3A	126.7	N1ⁱ—Cu1—O6	167.58 (7)
N2—C3—H3A	126.7	N1—Cu1—O6	89.80 (7)
C1—C4—C5	113.4 (2)	N1ⁱ—Cu1—O6ⁱ	89.80 (7)
C1—C4—H4A	108.9	N1—Cu1—O6ⁱ	167.58 (7)
C5—C4—H4A	108.9	O6—Cu1—O6ⁱ	85.48 (9)
C1—C4—H4B	108.9	N1ⁱ—Cu1—O5	113.70 (7)
C5—C4—H4B	108.9	N1—Cu1—O5	97.84 (7)
H4A—C4—H4B	107.7	O6—Cu1—O5	54.81 (6)
C4—C5—H5A	109.5	O6ⁱ—Cu1—O5	88.83 (7)
C4—C5—H5B	109.5	N3—O6—Cu1	105.39 (13)
H5A—C5—H5B	109.5	H1—O7—H2	113.6 (19)
C4—C5—H5C	109.5	N3—O5—Cu1	86.57 (13)
H5A—C5—H5C	109.5	O5—N3—O6	113.08 (18)
H5B—C5—H5C	109.5

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O7	0.86	1.99	2.830 (3)	167
O7—H1···O6ⁱⁱ	0.84 (1)	2.05 (2)	2.862 (2)	163 (3)
O7—H2···N3ⁱⁱⁱ	0.83 (1)	2.18 (1)	3.004 (3)	167 (3)

Symmetry codes: (ii) −x+3/2, y−1/2, z; (iii) −x+3/2, −y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	[Cu(NO₂)₂(C₅H₈N₂)]·2H₂O
M_r	383.86
Crystal system, space group	Orthorhombic, Pbcn
Temperature (K)	293
a, b, c (Å)	12.960 (6), 17.635 (7), 7.288 (3)
V (Å³)	1665.7 (12)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.35
Crystal size (mm)	0.30 × 0.25 × 0.20

Data collection
Diffractometer	Rigaku, SCXmini diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2005)
T_min, T_max	0.674, 0.763
No. of measured, independent and observed [I > 2σ(I)] reflections	16649, 1902, 1712
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.079, 1.10
No. of reflections	1902
No. of parameters	113
No. of restraints	5
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.24

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

N1—Cu1	1.9752 (17)	Cu1—O6ⁱ	2.0255 (15)
Cu1—N1ⁱ	1.9752 (17)	Cu1—O5	2.4501 (18)
Cu1—O6	2.0255 (15)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O7	0.86	1.99	2.830 (3)	166.7
O7—H1···O6ⁱⁱ	0.835 (11)	2.053 (15)	2.862 (2)	163 (3)
O7—H2···N3ⁱⁱⁱ	0.834 (11)	2.184 (12)	3.004 (3)	167 (3)

Symmetry codes: (ii) −x+3/2, y−1/2, z; (iii) −x+3/2, −y+1/2, z+1/2.

Acknowledgements

This work was supported by Southeast University.

References

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