catena-Poly[copper(II)-bis­(μ-3-cyano-2-hydroxy­propionato)-κ³N:O¹,O²;κ³O¹,O²:N-copper(II)]

The title compound, [Cu(C₄H₄NO₃)₂]_n, exhibits a double-chain structure extending along [100]. The Cu^II atom, lying on an inversion center, is coordinated by two cyano N atoms from two 3-cyano-2-hydroxy­propionate ligands and two hydr­oxy O atoms and two carboxyl­ate O atom from two other two ligands in a distorted octa­hedral geometry. Inter­molecular C—H...O and O—H...O hydrogen bonds connect the chains into a three-dimensional structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.023
• wR factor = 0.064
• Data-to-parameter ratio = 12.3

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT923_ALERT_1_A S    values in the CIF and FCF Differ by .......       0.18

Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          3
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          7
PLAT922_ALERT_1_C wR2 * 100.0 in the CIF and FCF Differ by .......      -0.20
PLAT927_ALERT_1_C Reported and Calculated  wR2 * 100.0 Differ by .      -0.20
PLAT928_ALERT_1_C Reported and Calculated    S value   Differ by .       0.18

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K
PLAT793_ALERT_4_G The Model has Chirality at C1      (Verify) ....          S

   1 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   4 ALERT level G = General alerts; check

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

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S1. Comment

β-Hydroxynitriles are potentially important intermediates in the synthesis of complex organic compounds (Seo et al., 1994). The study of coordination polymers with β-hydroxynitrile is rarely reported according to Cambridge Structural Database. Herein we report the structure of the title compound.

In the title compound, the Cu^II atom, lying on an inversion center, is six-coordinated in a distorted octahedral geometry defined by two carboxylate O atoms and two hydroxy O atoms in the equatorial plane and two N atoms from the cyano groups in the axial positions (Table 1 and Fig. 1). Weak coordination between the Cu^II atom and the N atoms is indicated by a Cu—N distance of 2.545 (2) Å, due to Jahn-Teller effects. The bond lengths and angles are in normal ranges (Klein et al., 1982; Wang et al., 2009). Adjacent Cu^II centers are bridged by two ligands, forming a double-chain structure, which is further extended by intermolecular C—H···O and O—H···O hydrogen bonds (Table 2) into a three-dimentional supramolecular structure.

Related literature

For the synthesis and studies of β-hydroxynitriles, see: Conti et al. (2003); Seo et al. (1994). For related structures, see: Klein et al. (1982); Wang et al. (2009).

S2. Experimental

2-Isoxazoline-3,5-dicarboxylic acid was synthesized according to the previously reported procedure (Conti et al., 2003). 3-Cyano-2-hydroxypropionic acid was obtained from 2-isoxazoline-3,5-dicarboxylic acid by selective cleavage of the N—O bond and decarboxylation under basic condition (Seo et al., 1994). A solution of Cu(NO₃)₂.3H₂O (0.048 g, 0.2 mmol) in H₂O (4 ml) was added to a solution of 3-cyano-2-hydroxypropionic acid (0.046 g, 0.4 mmol) in H₂O (8 ml), then aqueous triethylamine (0.07 ml) was added dropwise to the above solution accompanied with stirring. The mixture was flitered and placed at room temperature. Blue block crystals of the title compound were obtained in three days (yield 0.046 g, 78% based on Cu).

S3. Refinement

C-bound H atoms were positioned geometrically and refined as riding atoms, with C—H = 0.98 (CH) and 0.97 (CH₂) Å and with U_iso(H) = 1.2U_eq(C). The hydroxy H atom was found in a difference Fourier map and refined isotropically.

Computing details

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity. [Symmetry codes: (i) 1-x, -y, -z; (ii) x-1, y, z; (iii) 2-x, -y, -z.]
	Fig. 2. The one-dimensional double-chain in the title compound. Dashed lines denote hydrogen bonds.

catena-Poly[copper(II)-bis(µ-3-cyano-2-hydroxypropionato)- κ³N:O¹,O²;κ³O¹,O²:N- copper(II)]

Crystal data

[Cu(C4H4NO3)2]	F(000) = 294
Mr = 291.71	Dx = 1.854 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2150 reflections
a = 6.3704 (7) Å	θ = 3.2–26.0°
b = 8.4382 (10) Å	µ = 2.11 mm^−1
c = 10.0412 (12) Å	T = 293 K
β = 104.492 (2)°	Block, blue
V = 522.59 (11) Å^3	0.28 × 0.19 × 0.12 mm
Z = 2

Data collection

Bruker SMART APEX CCD diffractometer	1031 independent reflections
Radiation source: sealed tube	973 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
ϕ and ω scans	θmax = 26.0°, θmin = 3.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→7
Tmin = 0.624, Tmax = 0.776	k = −9→10
2803 measured reflections	l = −12→12

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)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0477P)^2 + 0.2506P] where P = (Fo^2 + 2Fc^2)/3
1031 reflections	(Δ/σ)max < 0.001
83 parameters	Δρmax = 0.32 e Å^−3
1 restraint	Δρmin = −0.27 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.5000	0.0000	0.0000	0.03130 (14)
N1	1.1980 (3)	0.1558 (3)	0.0646 (2)	0.0635 (6)
O1	0.69000 (19)	0.11889 (14)	0.15024 (11)	0.0264 (3)
H1W	0.671 (4)	0.117 (3)	0.2292 (14)	0.057 (7)*
O2	0.5444 (2)	0.17730 (15)	−0.10898 (11)	0.0364 (3)
O3	0.6908 (2)	0.41604 (15)	−0.09635 (12)	0.0384 (3)
C1	0.7140 (3)	0.28079 (19)	0.11473 (16)	0.0256 (3)
H1	0.6192	0.3473	0.1545	0.031*
C2	0.6441 (3)	0.2934 (2)	−0.04252 (16)	0.0274 (4)
C3	0.9491 (3)	0.3336 (2)	0.17056 (18)	0.0345 (4)
H3A	0.9641	0.4433	0.1454	0.041*
H3B	0.9880	0.3266	0.2701	0.041*
C4	1.0950 (3)	0.2340 (3)	0.1150 (2)	0.0419 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0435 (2)	0.0282 (2)	0.02069 (19)	−0.01409 (12)	0.00516 (14)	0.00079 (10)
N1	0.0422 (10)	0.0728 (14)	0.0791 (14)	−0.0038 (10)	0.0222 (10)	−0.0190 (12)
O1	0.0346 (6)	0.0251 (6)	0.0203 (5)	−0.0059 (5)	0.0080 (5)	−0.0001 (4)
O2	0.0537 (8)	0.0323 (7)	0.0217 (6)	−0.0152 (6)	0.0065 (5)	0.0008 (5)
O3	0.0626 (9)	0.0272 (7)	0.0284 (6)	−0.0107 (6)	0.0170 (6)	0.0016 (5)
C1	0.0333 (9)	0.0228 (8)	0.0232 (7)	−0.0030 (6)	0.0116 (6)	−0.0017 (6)
C2	0.0327 (8)	0.0276 (8)	0.0244 (8)	−0.0008 (7)	0.0120 (7)	0.0001 (6)
C3	0.0385 (10)	0.0351 (9)	0.0306 (8)	−0.0119 (8)	0.0099 (7)	−0.0069 (7)
C4	0.0307 (9)	0.0476 (11)	0.0465 (11)	−0.0109 (9)	0.0081 (8)	−0.0063 (9)

Geometric parameters (Å, º)

Cu1—O2	1.9159 (12)	O3—C2	1.238 (2)
Cu1—O1	1.9579 (11)	C1—C3	1.528 (2)
Cu1—N1^i	2.545 (2)	C1—C2	1.533 (2)
N1—C4	1.135 (3)	C1—H1	0.9800
O1—C1	1.4298 (19)	C3—C4	1.464 (3)
O1—H1W	0.832 (10)	C3—H3A	0.9700
O2—C2	1.264 (2)	C3—H3B	0.9700
O2^ii—Cu1—O2	180.0	C3—C1—C2	111.28 (14)
O2^ii—Cu1—O1	96.39 (5)	O1—C1—H1	109.3
O2—Cu1—O1	83.62 (5)	C3—C1—H1	109.3
O2—Cu1—O1^ii	96.38 (5)	C2—C1—H1	109.3
O1—Cu1—O1^ii	179.999 (1)	O3—C2—O2	124.17 (15)
O1—Cu1—N1^i	84.25 (6)	O3—C2—C1	117.92 (14)
O2—Cu1—N1^i	88.35 (6)	O2—C2—C1	117.90 (14)
O1^ii—Cu1—N1^i	95.74 (6)	C4—C3—C1	110.51 (15)
O2^ii—Cu1—N1^i	91.65 (6)	C4—C3—H3A	109.5
C1—O1—Cu1	112.43 (9)	C1—C3—H3A	109.5
C1—O1—H1W	108.0 (19)	C4—C3—H3B	109.5
Cu1—O1—H1W	120.9 (19)	C1—C3—H3B	109.5
C2—O2—Cu1	115.49 (10)	H3A—C3—H3B	108.1
O1—C1—C3	110.09 (14)	N1—C4—C3	175.7 (2)
O1—C1—C2	107.56 (12)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···O2^iii	0.98	2.54	3.240 (2)	128
O1—H1W···O3^iii	0.83 (2)	1.75 (2)	2.560 (2)	165 (4)

Symmetry code: (iii) x, −y+1/2, z+1/2.