Diammine(pyridine-2,6-dicarboxyl­ato)copper(II)

In the crystal structure of the title compound, [Cu(C₇H₃NO₄)(NH₃)₂], the Cu atom is coordinated in a square-pyramidal geometry by a pyridine-2,6-dicarboxyl­ate ligand acting in an N,O,O'-tridentate chelating mode, and by two N atoms from two ammine ligands. A further long Cu-O bond involving a symmetry-realated mol­ecule generates chains of mol­ecules in the a-axis direction.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.037
• wR factor = 0.104
• Data-to-parameter ratio = 13.8

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT415_ALERT_2_B Short Inter D-H..H-X       H2C    ..  H4      ..       2.02 Ang.

Alert level C
PLAT420_ALERT_2_C D-H Without Acceptor       N3     -   H3C    ...          ?

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

   0 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
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

The multifunctional ligand H2PDC (pyridine-2,6-dicarboxylic acid) is of particular interest for obtaining metal organic frameworks because of its potential coordinating sites, from a carboxylic acid group, which when deprotonated results in a divalent anion, and a neutral aromatic nitrogen coordinating site (Eubank et al., 2005). In the molecule of the title compound, the central Cu^II atom is chelated by a PDC²⁻ ligand and two ammine ligands, giving a square pyramidal coordination geometry (Fig. 1). In addition, as shown in Fig. 2, a weak interaction between Cu^II and an O atom from a symmetry-related molecule (Table 1) connects molecules into one-dimensional chains in the a-axis direction. In the crystal structure, intermolecular hydrogen bonds connect the one-dimensional molecular chains into a two-dimensional framework perpendicular to the b axis (Table 2 and Fig. 3).

S2. Experimental

Following the procedure described by Constable et al., (1990), H2PDC (0.083 g, 0.5 mmol) was added with 1 ml of concentrated ammine to an aqueous solution (15 ml) of copper(II) oxalate (0.075 g, 0.5 mmol). The mixture was placed in a 25 ml Teflon-lined Parr bomb and heated at 433 K for 38 h. The bomb was then cooled to room temperature at 5 K h⁻¹. Crystals were obtained in about 30% yield. Analysis calculated for C₇H₉N₃O₄Cu: C 32.00, H 3.45, N 15.99%; found: C 31.98, H 3.50, N 16.02%. IR (KBr, cm⁻¹): 3378 (m), 3065 (w), 1605 (vs), 1565 (m), 1556 (m), 1482 (s), 1417 (s).

S3. Refinement

H atoms were placed in calculated positions (C–H = 0.93 Å; U_iso(H) = 1.2U_eqC and N—H = 0.89 Å; U_iso(H) = 1.5U_eqN), and were included in the refinement in a riding-model approximation.

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of (I), showing 30% displacement ellipsoids and H atoms drawn as spheres of arbitrary radii.
	Fig. 2. Section of a one-dimensional chain of molecules of (I) connected by weak Cu—O bonds (shown as green dashed lines). The atoms labeled with suffixes a and b are related by the symmetry operators −1 + x, y, z and −2 + x, y, z respectively.
	Fig. 3. View of the hydrogen bonding in (I), shown as dashed lines. Thick green lines indicate the long Cu—O bonds.

Diammine(pyridine-2,6-dicarboxylate)copper(II)

Crystal data

[Cu(C7H3NO4)(NH3)2]	Z = 2
Mr = 262.72	F(000) = 266
Triclinic, P1	Dx = 2.006 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.8654 (6) Å	Cell parameters from 58 reflections
b = 9.1161 (11) Å	θ = 2.2–26.0°
c = 10.0916 (12) Å	µ = 2.51 mm^−1
α = 76.927 (2)°	T = 295 K
β = 86.987 (2)°	Needle, blue
γ = 86.618 (2)°	0.26 × 0.18 × 0.11 mm
V = 434.88 (9) Å^3

Data collection

Bruker APEX area-dectector diffractometer	1901 independent reflections
Radiation source: fine-focus sealed tube	1772 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.014
ϕ and ω scans	θmax = 27.8°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −6→5
Tmin = 0.558, Tmax = 0.755	k = −11→11
2693 measured reflections	l = −12→13

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.104	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0653P)^2 + 0.365P] where P = (Fo^2 + 2Fc^2)/3
1901 reflections	(Δ/σ)max = 0.001
138 parameters	Δρmax = 0.83 e Å^−3
0 restraints	Δρmin = −0.81 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
Cu1	0.29849 (7)	0.08868 (4)	0.20886 (3)	0.02474 (15)
N1	0.1509 (5)	0.2770 (3)	0.2411 (2)	0.0209 (4)
N2	0.0104 (5)	−0.0765 (3)	0.3523 (2)	0.0235 (5)
H2A	−0.1284	−0.0244	0.3841	0.035*
H2B	0.1049	−0.1301	0.4216	0.035*
H2C	−0.0560	−0.1383	0.3064	0.035*
N3	0.5141 (6)	−0.0849 (3)	0.1665 (3)	0.0308 (6)
H3A	0.6732	−0.0545	0.1247	0.046*
H3B	0.4199	−0.1264	0.1124	0.046*
H3C	0.5472	−0.1526	0.2433	0.046*
O4	0.6084 (5)	0.2681 (3)	0.4977 (2)	0.0357 (5)
O2	0.0093 (5)	0.1358 (2)	0.0668 (2)	0.0304 (5)
O3	0.5501 (4)	0.1156 (2)	0.3573 (2)	0.0276 (4)
O1	−0.3591 (5)	0.2906 (3)	0.0091 (2)	0.0375 (5)
C6	−0.1460 (6)	0.2528 (3)	0.0708 (3)	0.0247 (6)
C7	0.4940 (6)	0.2331 (3)	0.4036 (3)	0.0243 (5)
C2	0.2651 (6)	0.3363 (3)	0.3325 (3)	0.0216 (5)
C3	0.1780 (6)	0.4782 (3)	0.3500 (3)	0.0282 (6)
H3	0.2576	0.5210	0.4133	0.034*
C1	−0.0524 (6)	0.3479 (3)	0.1644 (3)	0.0219 (5)
C5	−0.1520 (6)	0.4895 (3)	0.1761 (3)	0.0272 (6)
H5	−0.2941	0.5399	0.1231	0.033*
C4	−0.0320 (7)	0.5546 (3)	0.2701 (3)	0.0311 (6)
H4	−0.0936	0.6505	0.2794	0.037*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0244 (2)	0.0220 (2)	0.0308 (2)	0.00593 (14)	−0.00732 (14)	−0.01257 (14)
N1	0.0209 (11)	0.0187 (10)	0.0238 (11)	0.0021 (8)	−0.0042 (9)	−0.0062 (8)
N2	0.0198 (11)	0.0239 (11)	0.0259 (11)	0.0070 (9)	−0.0056 (9)	−0.0042 (9)
N3	0.0302 (13)	0.0285 (13)	0.0382 (14)	0.0074 (10)	−0.0086 (11)	−0.0177 (11)
O4	0.0407 (13)	0.0327 (11)	0.0375 (12)	0.0058 (10)	−0.0197 (10)	−0.0136 (10)
O2	0.0317 (11)	0.0292 (11)	0.0345 (11)	0.0056 (9)	−0.0104 (9)	−0.0157 (9)
O3	0.0267 (10)	0.0261 (10)	0.0323 (10)	0.0064 (8)	−0.0083 (8)	−0.0116 (8)
O1	0.0341 (12)	0.0393 (13)	0.0429 (13)	0.0058 (10)	−0.0186 (10)	−0.0153 (10)
C6	0.0255 (14)	0.0243 (13)	0.0245 (13)	−0.0021 (11)	−0.0050 (11)	−0.0051 (10)
C7	0.0214 (13)	0.0245 (13)	0.0269 (13)	0.0012 (10)	−0.0052 (10)	−0.0051 (10)
C2	0.0207 (12)	0.0205 (12)	0.0252 (13)	−0.0005 (10)	−0.0044 (10)	−0.0075 (10)
C3	0.0293 (15)	0.0272 (14)	0.0324 (15)	0.0002 (11)	−0.0061 (12)	−0.0149 (12)
C1	0.0198 (13)	0.0213 (12)	0.0247 (13)	−0.0002 (10)	−0.0028 (10)	−0.0048 (10)
C5	0.0260 (14)	0.0231 (13)	0.0319 (14)	0.0044 (11)	−0.0073 (11)	−0.0047 (11)
C4	0.0362 (16)	0.0205 (13)	0.0391 (16)	0.0071 (12)	−0.0066 (13)	−0.0128 (12)

Geometric parameters (Å, º)

Cu1—N1	1.911 (2)	O4—C7	1.236 (3)
Cu1—N3	1.962 (3)	O2—C6	1.278 (4)
Cu1—O2	2.021 (2)	O3—C7	1.273 (4)
Cu1—O3	2.049 (2)	O1—C6	1.229 (4)
Cu1—N2	2.319 (2)	C6—C1	1.520 (4)
O1—Cu1^i	2.925 (2)	C7—C2	1.515 (4)
N1—C2	1.329 (3)	C2—C3	1.384 (4)
N1—C1	1.332 (4)	C3—C4	1.389 (4)
N2—H2A	0.8900	C3—H3	0.9300
N2—H2B	0.8900	C1—C5	1.381 (4)
N2—H2C	0.8900	C5—C4	1.396 (4)
N3—H3A	0.8900	C5—H5	0.9300
N3—H3B	0.8900	C4—H4	0.9300
N3—H3C	0.8900
N1—Cu1—N3	169.27 (11)	H3B—N3—H3C	109.5
N1—Cu1—O2	80.68 (9)	C6—O2—Cu1	114.41 (18)
N3—Cu1—O2	104.03 (10)	C7—O3—Cu1	114.95 (18)
N1—Cu1—O3	79.60 (9)	O1—C6—O2	125.9 (3)
N3—Cu1—O3	94.95 (10)	O1—C6—C1	119.5 (3)
O2—Cu1—O3	160.08 (9)	O2—C6—C1	114.6 (2)
N1—Cu1—N2	100.57 (9)	O4—C7—O3	126.2 (3)
N3—Cu1—N2	89.13 (10)	O4—C7—C2	119.4 (3)
O2—Cu1—N2	90.40 (9)	O3—C7—C2	114.5 (2)
O3—Cu1—N2	95.96 (9)	N1—C2—C3	120.5 (3)
C2—N1—C1	122.7 (2)	N1—C2—C7	111.7 (2)
C2—N1—Cu1	119.09 (19)	C3—C2—C7	127.8 (2)
C1—N1—Cu1	118.12 (19)	C2—C3—C4	117.8 (3)
Cu1—N2—H2A	109.5	C2—C3—H3	121.1
Cu1—N2—H2B	109.5	C4—C3—H3	121.1
H2A—N2—H2B	109.5	N1—C1—C5	120.5 (3)
Cu1—N2—H2C	109.5	N1—C1—C6	111.3 (2)
H2A—N2—H2C	109.5	C5—C1—C6	128.2 (3)
H2B—N2—H2C	109.5	C1—C5—C4	117.7 (3)
Cu1—N3—H3A	109.5	C1—C5—H5	121.1
Cu1—N3—H3B	109.5	C4—C5—H5	121.1
H3A—N3—H3B	109.5	C3—C4—C5	120.9 (3)
Cu1—N3—H3C	109.5	C3—C4—H4	119.6
H3A—N3—H3C	109.5	C5—C4—H4	119.6

Symmetry code: (i) x−1, y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O3^i	0.89	1.95	2.765 (3)	152
N2—H2B···O4^ii	0.89	1.91	2.739 (3)	155
N2—H2C···N3^i	0.89	2.55	3.148 (4)	126
N3—H3A···O2^iii	0.89	2.41	3.204 (4)	149
N3—H3B···O1^iv	0.89	2.18	3.007 (3)	154

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