Redetermination of bis(L-asparaginato)copper(II)

The Cu atom of the title compound, [Cu(C₄H₇N₂O₃)₂], is in a tetragonally distorted octahedral environment. A carboxyl O atom and the α-amino N atom from each ligand coordinate to Cu in a trans square-planar configuration [Cu—O = 2.003 (3) and 2.020 (3) Å, and Cu—N = 2.029 (4) and 2.049 (4) Å]. The octa­hedron is completed by bridging amide O atoms from adjacent mol­ecules [Cu—O = 2.229 (4) Å and Cu—O = 2.885 (4) Å] separated by c translations. This arrangement creates infinite chains linked in the [001] direction, stabilized by intra- and intermolecular N—H...O bonds. The structure has already been published [Stephens, Vagg & Williams (1975). Acta Cryst. B31, 841–845]; this redetermination reports the structure with higher precision.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.034
• wR factor = 0.092
• Data-to-parameter ratio = 6.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       6.23
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.22

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           73.90
           From the CIF: _reflns_number_total               1228
           Count of symmetry unique reflns         1228
           Completeness (_total/calc)            100.00%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present          yes

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

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

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Computing details

Data collection: CAD-4-PC (Enraf-Nonius, 1993); cell refinement: CAD-4-PC; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999).

(I)

Crystal data

[Cu(C4H7N2O3)2]	F(000) = 334
Mr = 325.77	Dx = 1.857 Mg m^−3
Monoclinic, P21	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 5.036 (2) Å	θ = 14.4–58.3°
b = 18.915 (2) Å	µ = 2.99 mm^−1
c = 6.152 (1) Å	T = 293 K
β = 96.21 (2)°	Prism, blue
V = 582.6 (3) Å^3	0.21 × 0.20 × 0.08 mm
Z = 2

Data collection

Nonius CAD-4 diffractometer	1226 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 73.9°, θmin = 4.7°
ω–2θ scans	h = −6→6
Absorption correction: ψ scan North, Phillips & Mathews (1968)	k = 0→23
Tmin = 0.572, Tmax = 0.796	l = −4→7
2230 measured reflections	2 standard reflections every 120 min
1228 independent reflections	intensity decay: <1.0%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.034	w = 1/[σ^2(Fo^2) + (0.0527P)^2 + 0.3521P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.092	(Δ/σ)max = 0.002
S = 1.23	Δρmax = 0.44 e Å^−3
1228 reflections	Δρmin = −0.58 e Å^−3
197 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.058 (3)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.05 (5)

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
Cu	0.78210 (12)	0.62217 (4)	0.22094 (10)	0.0328 (3)
O11	0.5925 (6)	0.71513 (17)	0.2267 (5)	0.0289 (6)
O12	0.5780 (9)	0.8239 (2)	0.0992 (7)	0.0485 (10)
O13	1.1285 (9)	0.6765 (2)	−0.4130 (6)	0.0451 (9)
N11	1.0333 (8)	0.6784 (2)	0.0508 (6)	0.0275 (7)
H1N	1.176 (10)	0.680 (3)	0.158 (8)	0.033*
H2N	1.081 (11)	0.659 (3)	−0.056 (8)	0.033*
N12	1.1722 (9)	0.7923 (3)	−0.4892 (7)	0.0363 (9)
H3N	1.088 (13)	0.830 (3)	−0.512 (12)	0.044*
H4N	1.276 (12)	0.787 (4)	−0.583 (9)	0.044*
C11	0.6800 (9)	0.7654 (2)	0.1141 (7)	0.0271 (9)
C12	0.9237 (8)	0.7494 (2)	−0.0097 (7)	0.0239 (8)
H2A	1.0620	0.7848	0.0319	0.029*
C13	0.8352 (9)	0.7567 (3)	−0.2569 (7)	0.0290 (9)
H3A	0.6861	0.7251	−0.2971	0.035*
H3B	0.7748	0.8046	−0.2881	0.035*
C14	1.0608 (9)	0.7393 (3)	−0.3938 (7)	0.0279 (9)
O21	1.0112 (7)	0.53481 (19)	0.2708 (6)	0.0355 (8)
O22	1.0387 (9)	0.4344 (2)	0.4533 (7)	0.0442 (9)
O23	0.5274 (8)	0.57414 (19)	0.9404 (5)	0.0359 (7)
N21	0.5907 (8)	0.5780 (2)	0.4653 (6)	0.0281 (8)
H5N	0.564 (11)	0.611 (3)	0.565 (8)	0.034*
H6N	0.452 (11)	0.555 (3)	0.391 (9)	0.034*
N22	0.3578 (11)	0.4669 (3)	1.0040 (9)	0.0463 (11)
H7N	0.367 (15)	0.422 (2)	0.996 (13)	0.056*
H8N	0.274 (14)	0.479 (4)	1.112 (9)	0.056*
C21	0.9529 (9)	0.4945 (2)	0.4243 (7)	0.0278 (9)
C22	0.7815 (8)	0.5280 (2)	0.5880 (7)	0.0258 (8)
H2B	0.9018	0.5566	0.6883	0.031*
C23	0.6522 (9)	0.4753 (2)	0.7254 (7)	0.0303 (9)
H3C	0.7882	0.4437	0.7939	0.036*
H3D	0.5263	0.4471	0.6315	0.036*
C24	0.5075 (9)	0.5095 (2)	0.9008 (7)	0.0286 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.0370 (4)	0.0256 (4)	0.0398 (4)	0.0090 (3)	0.0231 (3)	0.0118 (3)
O11	0.0312 (15)	0.0250 (15)	0.0327 (15)	0.0015 (13)	0.0137 (12)	0.0023 (12)
O12	0.059 (2)	0.0275 (18)	0.065 (2)	0.0135 (17)	0.034 (2)	0.0093 (18)
O13	0.061 (3)	0.0322 (19)	0.047 (2)	0.0100 (18)	0.0274 (17)	0.0035 (16)
N11	0.0302 (18)	0.0242 (18)	0.0293 (18)	0.0052 (15)	0.0093 (14)	0.0033 (15)
N12	0.040 (2)	0.039 (2)	0.032 (2)	−0.0010 (19)	0.0142 (17)	−0.0002 (18)
C11	0.032 (2)	0.024 (2)	0.0268 (19)	−0.0007 (17)	0.0099 (16)	0.0002 (16)
C12	0.0276 (19)	0.022 (2)	0.0229 (18)	0.0006 (15)	0.0076 (15)	0.0030 (14)
C13	0.030 (2)	0.035 (2)	0.0237 (19)	0.0046 (18)	0.0083 (16)	0.0021 (16)
C14	0.036 (2)	0.028 (2)	0.0213 (18)	0.0012 (18)	0.0088 (16)	−0.0002 (16)
O21	0.0387 (17)	0.0332 (17)	0.0387 (17)	0.0075 (14)	0.0226 (14)	0.0059 (14)
O22	0.050 (2)	0.0325 (19)	0.055 (2)	0.0130 (16)	0.0273 (18)	0.0070 (17)
O23	0.053 (2)	0.0249 (15)	0.0321 (16)	−0.0028 (15)	0.0138 (14)	−0.0024 (13)
N21	0.0308 (18)	0.0275 (19)	0.0277 (17)	0.0031 (15)	0.0111 (14)	0.0010 (14)
N22	0.062 (3)	0.031 (2)	0.053 (3)	−0.006 (2)	0.039 (2)	−0.010 (2)
C21	0.029 (2)	0.028 (2)	0.0280 (19)	−0.0006 (17)	0.0122 (16)	−0.0007 (17)
C22	0.0273 (18)	0.0250 (19)	0.0262 (19)	0.0013 (16)	0.0085 (15)	0.0001 (16)
C23	0.036 (2)	0.027 (2)	0.031 (2)	0.0038 (18)	0.0173 (18)	0.0011 (17)
C24	0.036 (2)	0.027 (2)	0.0251 (18)	0.0013 (18)	0.0115 (16)	0.0012 (17)

Geometric parameters (Å, º)

Cu—O11	2.003 (3)	C13—C14	1.522 (6)
Cu—O21	2.020 (3)	C13—H3A	0.9700
Cu—N11	2.029 (4)	C13—H3B	0.9700
Cu—N21	2.049 (4)	O21—C21	1.273 (6)
Cu—O13^i	2.885 (4)	O22—C21	1.222 (6)
Cu—O23^ii	2.229 (4)	O23—C24	1.249 (6)
O11—C11	1.282 (6)	N21—C22	1.493 (6)
O12—C11	1.219 (6)	N21—H5N	0.90 (4)
O13—C14	1.244 (6)	N21—H6N	0.90 (4)
N11—C12	1.483 (5)	N22—C24	1.313 (7)
N11—H1N	0.92 (4)	N22—H7N	0.86 (5)
N11—H2N	0.81 (4)	N22—H8N	0.85 (5)
N12—C14	1.317 (7)	C21—C22	1.533 (6)
N12—H3N	0.84 (4)	C22—C23	1.501 (6)
N12—H4N	0.82 (4)	C22—H2B	0.9800
C11—C12	1.543 (6)	C23—C24	1.511 (6)
C12—C13	1.543 (5)	C23—H3C	0.9700
C12—H2A	0.9800	C23—H3D	0.9700
O11—Cu—O21	168.86 (15)	C12—C13—H3A	109.2
O11—Cu—N11	82.75 (14)	C14—C13—H3B	109.2
O21—Cu—N11	97.44 (15)	C12—C13—H3B	109.2
O11—Cu—N21	94.70 (14)	H3A—C13—H3B	107.9
O21—Cu—N21	82.04 (14)	O13—C14—N12	123.3 (5)
N11—Cu—N21	164.02 (16)	O13—C14—C13	119.2 (4)
O11—Cu—O23^ii	97.81 (14)	N12—C14—C13	117.5 (4)
O21—Cu—O23^ii	93.18 (15)	C21—O21—Cu	115.4 (3)
N11—Cu—O23^ii	98.80 (14)	C24—O23—Cu^i	125.3 (3)
N21—Cu—O23^ii	97.18 (15)	C22—N21—Cu	107.5 (3)
O23^ii—Cu—O13^i	176.61 (13)	C22—N21—H5N	103 (4)
O11—Cu—O13^i	85.56 (12)	Cu—N21—H5N	109 (4)
O21—Cu—O13^i	83.45 (13)	C22—N21—H6N	112 (4)
N11—Cu—O13^i	81.82 (14)	Cu—N21—H6N	103 (4)
N21—Cu—O13^i	82.26 (14)	H5N—N21—H6N	121 (6)
C11—O11—Cu	116.7 (3)	C24—N22—H7N	123 (5)
C12—N11—Cu	111.6 (3)	C24—N22—H8N	124 (6)
C12—N11—H1N	113 (4)	H7N—N22—H8N	111 (8)
Cu—N11—H1N	97 (4)	O22—C21—O21	124.0 (4)
C12—N11—H2N	110 (4)	O22—C21—C22	120.3 (4)
Cu—N11—H2N	116 (4)	O21—C21—C22	115.5 (4)
H1N—N11—H2N	109 (6)	N21—C22—C23	114.3 (4)
C14—N12—H3N	119 (5)	N21—C22—C21	107.9 (3)
C14—N12—H4N	125 (5)	C23—C22—C21	113.9 (4)
H3N—N12—H4N	109 (7)	N21—C22—H2B	106.8
O12—C11—O11	123.1 (4)	C23—C22—H2B	106.8
O12—C11—C12	119.5 (4)	C21—C22—H2B	106.8
O11—C11—C12	117.4 (4)	C22—C23—C24	113.0 (4)
N11—C12—C11	110.4 (3)	C22—C23—H3C	109.0
N11—C12—C13	112.8 (3)	C24—C23—H3C	109.0
C11—C12—C13	108.0 (3)	C22—C23—H3D	109.0
N11—C12—H2A	108.5	C24—C23—H3D	109.0
C11—C12—H2A	108.5	H3C—C23—H3D	107.8
C13—C12—H2A	108.5	O23—C24—N22	123.0 (4)
C14—C13—C12	111.9 (4)	O23—C24—C23	121.6 (4)
C14—C13—H3A	109.2	N22—C24—C23	115.4 (4)
O21—Cu—O11—C11	98.0 (7)	N11—Cu—O21—C21	161.3 (3)
N11—Cu—O11—C11	6.3 (3)	N21—Cu—O21—C21	−2.6 (3)
N21—Cu—O11—C11	170.4 (3)	O23^ii—Cu—O21—C21	−99.4 (3)
O23^ii—Cu—O11—C11	−91.6 (3)	O11—Cu—N21—C22	−147.8 (3)
O11—Cu—N11—C12	−9.9 (3)	O21—Cu—N21—C22	21.5 (3)
O21—Cu—N11—C12	−178.7 (3)	N11—Cu—N21—C22	−67.8 (7)
N21—Cu—N11—C12	−91.6 (6)	O23^ii—Cu—N21—C22	113.7 (3)
O23^ii—Cu—N11—C12	86.9 (3)	Cu—O21—C21—O22	167.2 (4)
Cu—O11—C11—O12	178.0 (4)	Cu—O21—C21—C22	−17.6 (5)
Cu—O11—C11—C12	−1.1 (5)	Cu—N21—C22—C23	−162.1 (3)
Cu—N11—C12—C11	11.6 (4)	Cu—N21—C22—C21	−34.4 (4)
Cu—N11—C12—C13	−109.3 (3)	O22—C21—C22—N21	−149.2 (4)
O12—C11—C12—N11	173.7 (4)	O21—C21—C22—N21	35.5 (5)
O11—C11—C12—N11	−7.2 (5)	O22—C21—C22—C23	−21.2 (6)
O12—C11—C12—C13	−62.6 (6)	O21—C21—C22—C23	163.4 (4)
O11—C11—C12—C13	116.5 (4)	N21—C22—C23—C24	−61.2 (5)
N11—C12—C13—C14	−55.8 (5)	C21—C22—C23—C24	174.2 (4)
C11—C12—C13—C14	−178.0 (4)	Cu^i—O23—C24—N22	79.4 (6)
C12—C13—C14—O13	73.8 (6)	Cu^i—O23—C24—C23	−101.9 (4)
C12—C13—C14—N12	−107.2 (5)	C22—C23—C24—O23	−8.7 (7)
O11—Cu—O21—C21	71.1 (8)	C22—C23—C24—N22	170.2 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N11—H1N···O11^iii	0.92 (4)	2.20 (5)	2.987 (5)	143 (5)
N11—H2N···O13	0.81 (4)	2.26 (5)	2.944 (5)	143 (6)
N12—H3N···O22^iv	0.84 (4)	2.11 (5)	2.908 (7)	158 (7)
N12—H4N···O11^v	0.82 (4)	2.49 (5)	3.235 (5)	151 (6)
N21—H5N···O13^vi	0.90 (4)	2.54 (5)	3.135 (5)	125 (4)
N21—H5N···O23	0.90 (4)	2.44 (5)	2.975 (5)	119 (5)
N21—H6N···O21^vii	0.90 (4)	2.30 (5)	3.141 (6)	156 (6)
N22—H7N···O12^viii	0.86 (5)	1.97 (5)	2.805 (6)	165 (8)
N22—H8N···O21^vi	0.85 (5)	2.03 (5)	2.830 (6)	157 (7)

Symmetry codes: (iii) x+1, y, z; (iv) −x+2, y+1/2, −z; (v) x+1, y, z−1; (vi) x−1, y, z+1; (vii) x−1, y, z; (viii) −x+1, y−1/2, −z+1.