catena-Poly[[bis­(nitrato-κO)copper(II)]-μ-1,4-bis­(4,5-dihydro-1,3-oxazol-2-yl)­benzene-κ²N:N′]

In the title coordination polymer, [Cu(NO₃)₂(C₁₂H₁₂N₂O₂)]_n, the Cu^II ion, situated on an inversion center, is coordinated by two O atoms from two nitrate anions and two N atoms from two 1,4-bis­(4,5-dihydro-1,3-oxazol-2-yl)benzene (L) ligands in a distorted square-planar geometry. Each L ligand also lies across an inversion center and bridges two Cu^II ions, forming a polymeric chain running along the [101] direction. The three O atoms of the nitrate group are disordered over two positions in a 3:2 ratio.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.004 Å
• Disorder in main residue
• R factor = 0.034
• wR factor = 0.095
• Data-to-parameter ratio = 9.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       9.80
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         18
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          9
PLAT918_ALERT_3_C Reflection(s) # with I(obs) much smaller I(calc)          1

Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          1
PLAT153_ALERT_1_G The su's on the Cell Axes   are Equal (x 100000)         80 Ang.
PLAT154_ALERT_1_G The su's on the Cell Angles are Equal  (x 10000)        200 Deg.
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Cu     --  O3      ..       6.00 su
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Cu     --  N1      ..       6.00 su
PLAT301_ALERT_3_G Note: Main Residue  Disorder ...................         24 Perc.
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #         24
              O4   -N2   -O4'     1.555   1.555   1.555             39.00 Deg.
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #         25
              O2'  -N2   -O2      1.555   1.555   1.555             23.80 Deg.
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #         30
              O3   -N2   -O3'     1.555   1.555   1.555             22.90 Deg.
PLAT811_ALERT_5_G No ADDSYM Analysis: Too Many Excluded Atoms ....          !

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   4 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  10 ALERT level G = General information/check it is not something unexpected

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

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S1. Comment

The synthesis of metal coordination polymers has been a subject of intense research due to their interesting structural chemistry and potential applications in gas storage, separation, catalysis, magnetism, luminescence, and drug delivery (Kitagawa et al., 2004). The Ag^I complexes containing 1,4-bis(4,5-dihydro-2-oxazolyl)benzene ligands has been reported, which show various two-dimensional networks (Wang et al., 2008). The Cu···Cu distance separated by the bridging ligands is 9.289 (1) Å, while the ligands adopt the anti conformation in the structure. The 1-D chain of the title compound forms 3-D supramolecular structure which is interlinked by nitrate anions through C–H···O hydrogen bonds.

Related literature

For background to coordination polymers with organic ligands, see: Kitagawa et al. (2004). For related structures, see: Wang et al. (2008).

S2. Experimental

An aqueous solution (5.0 ml) of copper nitrate (1.0 mmol) was layered carefully over a methanolic solution (5.0 ml) of 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (1.0 mmol) in a tube. Blue crystals were obtained after several weeks. These were washed with methanol and collected in 55.0% yield.

S3. Refinement

H atoms were constrained to ideal geometries, with C—H = 0.93 (phenyl) or 0.97 (methylene) Å and U_iso(H) = 1.2U_eq(C). The O atoms of the nitrate group are disordered over two positions in a 3:2 ratio in the structure.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997) and SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. A portion of the chain structure. Ellipsoids are drawn at 30% probability level, and H atoms of spheres of arbitrary radius. Symmetry codes: (i) 1 - x, 1 - y, 1 - z; (ii) -x, 1 - y, -z. The disorder is not shown for clarity.

catena-Poly[[bis(nitrato-κO)copper(II)]- µ-1,4-bis(4,5-dihydro-1,3-oxazol-2-yl)benzene-κ²N:N']

Crystal data

[Cu(NO3)2(C12H12N2O2)]	Z = 1
Mr = 403.80	F(000) = 205
Triclinic, P1	Dx = 1.852 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.5240 (8) Å	Cell parameters from 1976 reflections
b = 7.5852 (8) Å	θ = 2.5–26.0°
c = 8.3161 (8) Å	µ = 1.56 mm^−1
α = 90.393 (2)°	T = 297 K
β = 103.556 (2)°	Parallelepiped, blue
γ = 114.314 (2)°	0.56 × 0.52 × 0.31 mm
V = 362.09 (7) Å^3

Data collection

Bruker SMART 1000 diffractometer	1392 independent reflections
Radiation source: fine-focus sealed tube	1384 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
ϕ and ω scans	θmax = 26.0°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −8→7
Tmin = 0.433, Tmax = 0.616	k = −8→9
2053 measured reflections	l = −7→10

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.095	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0698P)^2 + 0.1776P] where P = (Fo^2 + 2Fc^2)/3
1392 reflections	(Δ/σ)max = 0.001
142 parameters	Δρmax = 0.29 e Å^−3
0 restraints	Δρmin = −0.44 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cu	0.5000	0.5000	0.5000	0.02820 (18)
N1	0.5908 (3)	0.6368 (3)	0.3097 (2)	0.0301 (4)
N2	0.5360 (5)	0.1919 (3)	0.3813 (3)	0.0423 (5)
O1	0.6228 (3)	0.7793 (3)	0.0775 (2)	0.0392 (4)
O2	0.6917 (12)	0.3558 (9)	0.4788 (8)	0.0408 (11)	0.60
O3	0.3378 (13)	0.1675 (8)	0.3452 (9)	0.0520 (14)	0.60
O4	0.6161 (11)	0.0764 (7)	0.3539 (7)	0.0586 (12)	0.60
O2'	0.719 (2)	0.3108 (16)	0.4449 (13)	0.050 (2)	0.40
O3'	0.3542 (17)	0.2391 (10)	0.3667 (12)	0.0364 (15)	0.40
O4'	0.4801 (17)	0.0347 (11)	0.2945 (10)	0.0634 (19)	0.40
C1	0.8447 (4)	0.7532 (4)	0.3336 (4)	0.0412 (6)
H1A	0.9246	0.6695	0.3378	0.049*
H1B	0.9119	0.8426	0.4353	0.049*
C2	0.8593 (4)	0.8615 (4)	0.1836 (4)	0.0423 (6)
H2A	0.9139	0.9999	0.2149	0.051*
H2B	0.9643	0.8423	0.1273	0.051*
C3	0.4874 (4)	0.6623 (3)	0.1666 (3)	0.0282 (4)
C4	0.2358 (4)	0.5773 (3)	0.0837 (3)	0.0281 (4)
C5	0.0729 (4)	0.4320 (4)	0.1458 (3)	0.0430 (6)
H5A	0.1211	0.3858	0.2442	0.052*
C6	0.1608 (4)	0.6452 (4)	−0.0632 (3)	0.0398 (6)
H6A	0.2687	0.7432	−0.1060	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.0260 (2)	0.0278 (2)	0.0279 (2)	0.01314 (17)	−0.00148 (15)	0.00318 (15)
N1	0.0231 (9)	0.0304 (10)	0.0319 (10)	0.0115 (8)	−0.0019 (7)	−0.0001 (7)
N2	0.0527 (16)	0.0355 (11)	0.0466 (13)	0.0223 (11)	0.0206 (11)	0.0115 (10)
O1	0.0270 (8)	0.0490 (10)	0.0338 (9)	0.0097 (7)	0.0056 (7)	0.0101 (8)
O2	0.036 (2)	0.038 (3)	0.050 (3)	0.0199 (18)	0.0077 (18)	0.005 (2)
O3	0.042 (3)	0.046 (4)	0.058 (3)	0.016 (3)	−0.0003 (19)	0.000 (3)
O4	0.088 (3)	0.049 (3)	0.062 (3)	0.045 (3)	0.031 (3)	0.013 (2)
O2'	0.042 (4)	0.056 (6)	0.055 (5)	0.028 (4)	0.005 (3)	0.009 (4)
O3'	0.035 (3)	0.025 (4)	0.044 (3)	0.012 (3)	0.000 (2)	−0.001 (3)
O4'	0.102 (6)	0.042 (3)	0.064 (5)	0.044 (4)	0.028 (4)	0.000 (3)
C1	0.0231 (11)	0.0453 (14)	0.0454 (14)	0.0103 (10)	−0.0007 (10)	0.0027 (11)
C2	0.0241 (11)	0.0472 (14)	0.0461 (14)	0.0084 (10)	0.0047 (10)	0.0041 (11)
C3	0.0254 (11)	0.0286 (10)	0.0288 (11)	0.0118 (8)	0.0036 (8)	0.0011 (8)
C4	0.0254 (10)	0.0317 (11)	0.0241 (10)	0.0122 (9)	0.0008 (8)	0.0013 (8)
C5	0.0308 (12)	0.0513 (15)	0.0354 (13)	0.0117 (11)	−0.0018 (10)	0.0199 (11)
C6	0.0272 (12)	0.0457 (14)	0.0354 (13)	0.0074 (10)	0.0028 (9)	0.0170 (11)

Geometric parameters (Å, º)

Cu—N1^i	1.971 (2)	O1—C3	1.337 (3)
Cu—N1	1.971 (2)	O1—C2	1.453 (3)
Cu—O2^i	2.005 (5)	C1—C2	1.498 (4)
Cu—O2	2.005 (5)	C1—H1A	0.9700
Cu—O3'^i	1.994 (6)	C1—H1B	0.9700
Cu—O3'	1.994 (6)	C2—H2A	0.9700
N1—C3	1.282 (3)	C2—H2B	0.9700
N1—C1	1.484 (3)	C3—C4	1.476 (3)
N2—O2'	1.152 (12)	C4—C5	1.383 (3)
N2—O3	1.190 (8)	C4—C6	1.390 (3)
N2—O4	1.234 (5)	C5—C6^ii	1.381 (4)
N2—O4'	1.258 (7)	C5—H5A	0.9300
N2—O2	1.340 (7)	C6—C5^ii	1.381 (4)
N2—O3'	1.354 (10)	C6—H6A	0.9300
N1^i—Cu—N1	180.0	O4—N2—O3'	150.9 (5)
N1^i—Cu—O3'^i	92.7 (3)	O4'—N2—O3'	112.3 (6)
N1—Cu—O3'^i	87.3 (3)	O2—N2—O3'	94.6 (4)
N1^i—Cu—O3'	87.3 (3)	C3—O1—C2	106.60 (19)
N1—Cu—O3'	92.7 (3)	N2—O2—Cu	103.0 (4)
O3'^i—Cu—O3'	180.000 (1)	N2—O3'—Cu	103.0 (5)
N1^i—Cu—O2^i	88.6 (2)	N1—C1—C2	103.7 (2)
N1—Cu—O2^i	91.4 (2)	N1—C1—H1A	111.0
O3'^i—Cu—O2^i	59.4 (3)	C2—C1—H1A	111.0
O3'—Cu—O2^i	120.6 (3)	N1—C1—H1B	111.0
N1^i—Cu—O2	91.4 (2)	C2—C1—H1B	111.0
N1—Cu—O2	88.6 (2)	H1A—C1—H1B	109.0
O3'^i—Cu—O2	120.6 (3)	O1—C2—C1	104.80 (19)
O3'—Cu—O2	59.4 (3)	O1—C2—H2A	110.8
O2^i—Cu—O2	180.000 (2)	C1—C2—H2A	110.8
C3—N1—C1	107.4 (2)	O1—C2—H2B	110.8
C3—N1—Cu	137.12 (16)	C1—C2—H2B	110.8
C1—N1—Cu	115.40 (16)	H2A—C2—H2B	108.9
O2'—N2—O3	139.9 (5)	N1—C3—O1	116.8 (2)
O2'—N2—O4	91.9 (5)	N1—C3—C4	128.7 (2)
O3—N2—O4	128.1 (4)	O1—C3—C4	114.5 (2)
O2'—N2—O4'	129.2 (6)	C5—C4—C6	119.0 (2)
O3—N2—O4'	90.1 (6)	C5—C4—C3	122.5 (2)
O4—N2—O4'	39.0 (4)	C6—C4—C3	118.5 (2)
O2'—N2—O2	23.8 (4)	C6^ii—C5—C4	120.6 (2)
O3—N2—O2	117.1 (4)	C6^ii—C5—H5A	119.7
O4—N2—O2	114.4 (4)	C4—C5—H5A	119.7
O4'—N2—O2	152.8 (6)	C5^ii—C6—C4	120.4 (2)
O2'—N2—O3'	117.1 (5)	C5^ii—C6—H6A	119.8
O3—N2—O3'	22.9 (3)	C4—C6—H6A	119.8

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