Poly[diaqua-μ-oxalato-μ-pyrazine-2-carbox­yl­ato-lanthanum(III)]

Abstract

In the title complex, [La(C₅H₃N₂O₂)(C₂O₄)(H₂O)₂]_n, the La^III ion is coordinated by one N and three O atoms from two pyrazine-2-carboxylate ligands, by four O atoms from two oxalate ligands and by two O atoms of two water molecules, displaying a distorted bicapped square-anti­prismatic geometry. The carboxyl­ate groups of pyrazine-2-carboxyl­ate and oxalate ligands link the lanthanum metal centres, forming layers parallel to (10). The layers are further connected by inter­molecular O—H⋯O and N—H⋯O hydrogen-bonding inter­actions, forming a three-dimensional supra­molecular network.

Related literature

For general background, see: Eddaoudi et al. (2001 ▶); Rizk et al. (2005 ▶); Zeng et al. (2007 ▶).

Experimental

Crystal data

• [La(C₅H₃N₂O₂)(C₂O₄)(H₂O)₂]

• M _r = 386.06

• Triclinic,

• a = 8.040 (3) Å

• b = 8.7343 (18) Å

• c = 8.8329 (18) Å

• α = 115.552 (2)°

• β = 101.447 (3)°

• γ = 95.789 (3)°

• V = 536.1 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 4.02 mm⁻¹

• T = 296 (2) K

• 0.17 × 0.16 × 0.14 mm

Data collection

• Bruker APEXII area-detector diffractometer

• Absorption correction: multi-scan (APEX2; Bruker, 2004 ▶) T _min = 0.548, T _max = 0.603 (expected range = 0.518–0.569)

• 2761 measured reflections

• 1898 independent reflections

• 1787 reflections with I > 2σ(I)

• R _int = 0.020

Refinement

• R[F ² > 2σ(F ²)] = 0.031

• wR(F ²) = 0.078

• S = 1.07

• 1898 reflections

• 163 parameters

• 6 restraints

• H-atom parameters constrained

• Δρ_max = 1.61 e Å⁻³

• Δρ_min = −1.22 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶), PLATON (Spek, 2003 ▶) and SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W⋯N1i	0.84	1.97	2.796 (6)	170
O2W—H3W⋯O2ii	0.84	1.94	2.737 (5)	157
O1W—H2W⋯O3iii	0.84	2.05	2.874 (5)	167
O2W—H4W⋯O6iv	0.84	2.09	2.825 (5)	146

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .

supplementary crystallographic information

Comment

The design, synthesis, characterization, and properties of supramolecular networks formed by using functionalized organic molecules as bridges between metal centers are of great interest(Eddaoudi et al., 2001; Rizk et al., 2005; Zeng et al.,2007). As a building block, pyrazine-2-carboxylic acid and oxalic acid are excellent candidates for the construction of supramolecular complexes. Herein, we reported the new coordination polymer, (I).

In (I), each La^III centre is coordinated by seven oxygen atoms and one nitrogen atom from two pyrazine-2-carboxylate ligands, two oxalate ligands and two water molecules (Fig. 1), and represents a distorted bicapped square antiprismatic geometry. The La^III ions are linked by pyrazine-2-carboxylate ligands and oxalate ligands to form layers parallel to the (1 0 -1) plane (Fig.2), and the adjacent La···La separations are 6.570 (4) and 4.506 (5) Å, respectively. O—H···O and N—H···O hydrogen bonds (Table 1), involving the pyrazine-2-carboxylate ligands, coordinating water molecules and oxalate ligands assemble neighboring layers into a three-dimensional supramolecular network motif .

Experimental

A mixture of La₂O₃ (0.245 g; 0.75 mmol), pyrazine-2-carboxylic acid (0.186 g; 1.5 mmol), oxalic acid(0.135 g; 1.5 mmol), water (10 mL) in the presence of HNO₃ (0.024 g; 0.385 mmol) was stirred vigorously for 20 min and then sealed in a Teflon-lined stainless-steel autoclave (20 mL, capacity). The autoclave was heated and maintained at 433K for 3 days, and then cooled to room temperature at 5 K h^-1 and obtained the colorless block crystals.

Refinement

Water H atoms were tentatively located in difference Fourier maps and were refined with distance restraints of O–H = 0.84 Å and H···H = 1.35 Å, and with U_iso(H) = 1.5 U_eq(O). In the last cycles of refinement they were treated as riding on the O atoms. Carbon-bound H atoms were placed at calculated positions and were treated as riding on their parent C atoms with C—H = 0.93 Å, and with U_iso(H) = 1.2 U_eq(C).

Figures

Fig. 1.

ORTEP view showing the atomic-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry codes: (i)1-x, 1-y, 1-z; (ii)1-x, -y, -z; (iii)1-x, -y, 1-z]

Fig. 2.

View of the layered network of the title structure.

Crystal data

[La(C5H3N2O2)(C2O4)(H2O)2]	Z = 2
Mr = 386.06	F(000) = 368
Triclinic, P1	Dx = 2.391 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.040 (3) Å	Cell parameters from 6377 reflections
b = 8.7343 (18) Å	θ = 1.7–28.0°
c = 8.8329 (18) Å	µ = 4.02 mm−1
α = 115.552 (2)°	T = 296 K
β = 101.447 (3)°	Block, colourless
γ = 95.789 (3)°	0.17 × 0.16 × 0.14 mm
V = 536.1 (3) Å3

Data collection

Bruker APEXII area-detector diffractometer	1898 independent reflections
Radiation source: fine-focus sealed tube	1787 reflections with I > 2σ(I)
graphite	Rint = 0.020
φ and ω scans	θmax = 25.2°, θmin = 2.6°
Absorption correction: multi-scan (APEX2; Bruker, 2004)	h = −5→9
Tmin = 0.548, Tmax = 0.603	k = −10→10
2761 measured reflections	l = −10→10

Refinement

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) = 0.078	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.0533P)2] where P = (Fo2 + 2Fc2)/3
1898 reflections	(Δ/σ)max < 0.001
163 parameters	Δρmax = 1.61 e Å−3
6 restraints	Δρmin = −1.22 e Å−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C1	0.2750 (6)	0.2794 (6)	0.7523 (6)	0.0218 (10)
C2	0.2577 (7)	0.4053 (7)	0.9066 (7)	0.0285 (11)
H2	0.3191	0.4122	1.0111	0.034*
C3	0.0676 (7)	0.4974 (7)	0.7564 (7)	0.0304 (12)
H3	−0.0079	0.5706	0.7529	0.036*
C4	0.0849 (7)	0.3716 (7)	0.6014 (7)	0.0289 (11)
H4	0.0202	0.3621	0.4968	0.035*
C5	0.5718 (6)	0.4928 (6)	0.5701 (6)	0.0204 (10)
C6	0.0553 (6)	−0.0282 (6)	−0.0653 (6)	0.0218 (10)
C7	0.3936 (6)	0.1564 (7)	0.7458 (6)	0.0238 (10)
La1	0.33941 (3)	0.08521 (3)	0.32247 (3)	0.01745 (13)
N1	0.1560 (6)	0.5173 (6)	0.9109 (6)	0.0284 (10)
N8	0.1914 (5)	0.2634 (5)	0.5974 (5)	0.0235 (9)
O1	0.3920 (5)	0.0398 (4)	0.5980 (4)	0.0248 (8)
O2	0.4933 (5)	0.1760 (5)	0.8841 (5)	0.0314 (8)
O3	0.5571 (5)	0.3495 (4)	0.5715 (4)	0.0246 (7)
O4	0.6879 (4)	0.6241 (4)	0.6678 (4)	0.0264 (8)
O5	−0.0155 (4)	−0.0721 (5)	−0.2201 (4)	0.0299 (8)
O6	0.2119 (4)	−0.0240 (5)	−0.0025 (4)	0.0292 (8)
O1W	0.2022 (5)	−0.2208 (4)	0.2499 (4)	0.0271 (8)
O2W	0.5746 (5)	0.1980 (5)	0.2097 (4)	0.0300 (8)
H1W	0.1827	−0.2913	0.1441	0.045*
H3W	0.5293	0.2079	0.1210	0.045*
H2W	0.2583	−0.2630	0.3071	0.045*
H4W	0.6611	0.1534	0.1900	0.045*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.018 (2)	0.027 (2)	0.021 (2)	0.007 (2)	0.005 (2)	0.012 (2)
C2	0.024 (3)	0.033 (3)	0.026 (3)	0.008 (2)	0.004 (2)	0.012 (2)
C3	0.030 (3)	0.030 (3)	0.033 (3)	0.012 (2)	0.010 (2)	0.014 (2)
C4	0.031 (3)	0.033 (3)	0.029 (3)	0.017 (2)	0.007 (2)	0.018 (2)
C5	0.015 (2)	0.025 (2)	0.021 (2)	0.0083 (19)	0.005 (2)	0.009 (2)
C6	0.017 (2)	0.023 (2)	0.024 (2)	0.0043 (19)	0.004 (2)	0.010 (2)
C7	0.018 (2)	0.033 (3)	0.025 (3)	0.005 (2)	0.007 (2)	0.016 (2)
La1	0.01352 (18)	0.01999 (18)	0.01806 (18)	0.00464 (11)	0.00163 (12)	0.00898 (13)
N1	0.022 (2)	0.027 (2)	0.031 (2)	0.0072 (18)	0.0067 (19)	0.0093 (19)
N8	0.022 (2)	0.027 (2)	0.023 (2)	0.0084 (17)	0.0035 (17)	0.0132 (18)
O1	0.0267 (19)	0.0270 (18)	0.0238 (18)	0.0104 (15)	0.0089 (15)	0.0126 (15)
O2	0.028 (2)	0.046 (2)	0.0244 (18)	0.0153 (17)	0.0049 (16)	0.0195 (17)
O3	0.0261 (19)	0.0225 (17)	0.0260 (18)	0.0047 (14)	0.0020 (15)	0.0143 (15)
O4	0.0196 (18)	0.0241 (18)	0.0316 (19)	0.0037 (15)	−0.0015 (15)	0.0131 (16)
O5	0.0172 (18)	0.049 (2)	0.0197 (18)	0.0097 (16)	0.0016 (15)	0.0132 (16)
O6	0.0147 (18)	0.046 (2)	0.0220 (17)	0.0100 (16)	0.0020 (14)	0.0123 (16)
O1W	0.0262 (19)	0.0239 (18)	0.0263 (18)	0.0031 (15)	0.0015 (15)	0.0100 (15)
O2W	0.027 (2)	0.039 (2)	0.0272 (19)	0.0109 (17)	0.0114 (16)	0.0166 (17)

Geometric parameters (Å, °)

C1—N8	1.340 (6)	C7—O1	1.259 (6)
C1—C2	1.378 (7)	La1—O1W	2.533 (3)
C1—C7	1.497 (7)	La1—O4i	2.536 (3)
C2—N1	1.330 (7)	La1—O6	2.544 (3)
C2—H2	0.9300	La1—O3	2.551 (3)
C3—N1	1.336 (7)	La1—O5ii	2.555 (4)
C3—C4	1.382 (7)	La1—O1	2.592 (3)
C3—H3	0.9300	La1—O2W	2.600 (4)
C4—N8	1.332 (7)	La1—O1iii	2.623 (3)
C4—H4	0.9300	La1—N8	2.828 (4)
C5—O4	1.242 (6)	La1—O2iii	2.889 (4)
C5—O3	1.250 (6)	La1—C7iii	3.124 (5)
C5—C5i	1.574 (9)	O1W—H1W	0.8385
C6—O5	1.239 (6)	O1W—H2W	0.8353
C6—O6	1.261 (6)	O2W—H3W	0.8400
C6—C6ii	1.539 (9)	O2W—H4W	0.8421
C7—O2	1.252 (6)
N8—C1—C2	122.0 (5)	O5ii—La1—O1iii	154.21 (12)
N8—C1—C7	115.3 (4)	O1—La1—O1iii	60.45 (13)
C2—C1—C7	122.7 (5)	O2W—La1—O1iii	75.58 (11)
N1—C2—C1	122.1 (5)	O1W—La1—N8	97.55 (12)
N1—C2—H2	118.9	O4i—La1—N8	72.37 (12)
C1—C2—H2	118.9	O6—La1—N8	128.17 (11)
N1—C3—C4	122.0 (5)	O3—La1—N8	68.57 (12)
N1—C3—H3	119.0	O5ii—La1—N8	66.44 (11)
C4—C3—H3	119.0	O1—La1—N8	58.52 (11)
N8—C4—C3	121.9 (5)	O2W—La1—N8	131.02 (12)
N8—C4—H4	119.0	O1iii—La1—N8	115.86 (11)
C3—C4—H4	119.0	O1W—La1—O2iii	66.41 (11)
O4—C5—O3	126.6 (4)	O4i—La1—O2iii	129.49 (11)
O4—C5—C5i	117.0 (5)	O6—La1—O2iii	68.05 (11)
O3—C5—C5i	116.4 (5)	O3—La1—O2iii	112.40 (11)
O5—C6—O6	126.1 (4)	O5ii—La1—O2iii	121.50 (11)
O5—C6—C6ii	118.0 (5)	O1—La1—O2iii	99.45 (10)
O6—C6—C6ii	115.9 (5)	O2W—La1—O2iii	65.10 (11)
O2—C7—O1	122.7 (5)	O1iii—La1—O2iii	46.83 (10)
O2—C7—C1	119.7 (5)	N8—La1—O2iii	157.23 (11)
O1—C7—C1	117.5 (4)	O1W—La1—C7iii	68.77 (12)
O2—C7—La1iii	67.6 (3)	O4i—La1—C7iii	137.10 (12)
O1—C7—La1iii	55.5 (3)	O6—La1—C7iii	91.66 (12)
C1—C7—La1iii	169.0 (3)	O3—La1—C7iii	95.00 (12)
O1W—La1—O4i	150.33 (12)	O5ii—La1—C7iii	139.98 (12)
O1W—La1—O6	82.82 (11)	O1—La1—C7iii	78.74 (11)
O4i—La1—O6	82.26 (12)	O2W—La1—C7iii	70.04 (12)
O1W—La1—O3	139.37 (10)	O1iii—La1—C7iii	23.29 (11)
O4i—La1—O3	63.95 (11)	N8—La1—C7iii	136.97 (12)
O6—La1—O3	136.33 (11)	O2iii—La1—C7iii	23.62 (11)
O1W—La1—O5ii	77.14 (12)	C2—N1—C3	116.0 (5)
O4i—La1—O5ii	73.25 (12)	C4—N8—C1	115.9 (4)
O6—La1—O5ii	63.19 (11)	C4—N8—La1	126.3 (3)
O3—La1—O5ii	124.85 (11)	C1—N8—La1	114.8 (3)
O1W—La1—O1	68.69 (11)	C7—O1—La1	122.9 (3)
O4i—La1—O1	122.78 (11)	C7—O1—La1iii	101.2 (3)
O6—La1—O1	151.51 (12)	La1—O1—La1iii	119.55 (13)
O3—La1—O1	71.74 (11)	C7—O2—La1iii	88.8 (3)
O5ii—La1—O1	108.11 (11)	C5—O3—La1	120.1 (3)
O1W—La1—O2W	130.93 (11)	C5—O4—La1i	120.6 (3)
O4i—La1—O2W	67.57 (12)	C6—O5—La1ii	121.0 (3)
O6—La1—O2W	72.86 (11)	C6—O6—La1	121.8 (3)
O3—La1—O2W	69.18 (11)	La1—O1W—H1W	113.1
O5ii—La1—O2W	123.82 (12)	La1—O1W—H2W	115.0
O1—La1—O2W	126.58 (11)	H1W—O1W—H2W	107.3
O1W—La1—O1iii	77.11 (11)	La1—O2W—H3W	111.1
O4i—La1—O1iii	132.53 (11)	La1—O2W—H4W	123.8
O6—La1—O1iii	114.65 (11)	H3W—O2W—H4W	106.5
O3—La1—O1iii	75.79 (11)

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

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···N1iv	0.84	1.97	2.796 (6)	170
O2W—H3W···O2v	0.84	1.94	2.737 (5)	157
O1W—H2W···O3iii	0.84	2.05	2.874 (5)	167
O2W—H4W···O6vi	0.84	2.09	2.825 (5)	146

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