Polymeric aqua­(nitrato-κ²O,O′)(1,10-phenanthroline-κ²N,N′)(2,3-pyrazine­di­carboxyl­ato-κ²N,O)­europium(III) monohydrate

In polymeric {[Eu(pzdc)(NO₃)(phen)(H₂O)]·H₂O}_n [pzdc is 2,3-pyrazine­di­carboxyl­ate (C₆H₂O₄) and phen is 1,10-phenanthroline (C₁₂H₈N₂)], each europium(III) ion is coordinated by seven O atoms (from three pzdc anions, a nitrate anion and a water mol­ecule) and the two N atoms of the phen ligand, resulting in a nine-coordinated europium(III) center with a distorted monocapped square-antiprismatic coordination polyhedron. Four pzdc anions bridge four europium(III) ions, forming a parallelogram unit, the four vertices of which are occupied by the four pzdc anions. Moreover, each parallelogram unit links six other adjacent parallelogram units, forming a two-dimensional network with disordered lattice water mol­ecules.

S1. Comment

In recent years, more and more attention has been focused on coordination polymers with multifunctional ligands, as the presence of different functional groups allows incorporation of interesting properties into the resulting coordination networks (Ayyappan, et al., 2001). Among the various organic ligands, 2,3-pyrazinedicarboxylic acid is a commonly used multifunctional ligand. Its complexes with d-block transition metals have been well studied; compounds that have been structurally documented include polymeric [Cu(pzdc)·HCl]_x, [Cu(pzdc)(H₂O)₂]_x.2xH₂O, [Fe(pzdc)(H₂O)₂]_x.2xH₂O and [Mn(pzdc)(H₂O)₂]_x.2xH₂O (O'Connor et al., 1982; Mao et al., 1996a; Gao et al., 1999; Mao et al., 1996b). However, the lanthanide complexes of this ligand are almost structurally unexplored. In light of the fact that lanthanide and d-block transition metal ions differ in their coordination number, pzdc may coordinate with them in a different manner, so we selected the europium–pzdc–phen system in order to extend this research. In the title compound, [(pzdc)(NO₃)(phen)(H₂O)Eu]·H₂O, (I), the europium(III) ion is linked to four different ligands.

In (I), each europium(III) ion coordinates to three O atoms from three carboxylate groups of three pzdc anions, with a typical Eu—O(carboxylate) distance range [2.331 (3)–2.398 (3) Å; Li et al., 2002), one water molecule, with a longer Eu—O distance [2.530 (4) Å], one heterocycle N atom, with an Eu—N distance of 2.597 (4) Å, and two N atoms of phen in a chelating fashion, with Eu—N distances of 2.570 (4) and 2.582 (4) Å, resulting in a distorted monocap square- antiprismatic coordination polyhedron (Fig. 1). The square plane formed by atoms O5, O6, N1 and N2, with a mean deviation of 0.2280 Å, is significantly distorted, but the mean deviation of the other square plane, containing atoms O1, N3, O3ⁱ and O4ⁱⁱ [symmetry codes: (i) −x + 1, y − 1/2, −z + 3/2; (ii) x, −y + 3/2, z − 1/2], is only 0.0849 Å, comparable with the deviations found in the Eu–phen analogue [Eu₂(p-BDC)₃(phen)₂(H₂O)₂]_n (p-BDC is 1,4-benzenedicarboxylate; Wang, et al., 2003). To complete the coordination environment of the europium(III) center, atom O1W is located on the cap. Obviously, the pzdc anion acts as a tetradentate ligand, bridging three europium(III) ions, and adopts only one bridging mode. Four pzdc anions bridge four europium(III) ions into a parallelogram unit with approximate dimensions of 10.293 and 13.176 Å, the four vertices of which are occupied by the four pzdc anions. Moreover, each parallelogram unit links six other adjacent parallelogram units, forming a two-dimensional network (Fig. 2). The pzdc anion displays three types of bridging; bridging by the anion is also found in [Eu₂(pzdc)₃(H₂O)]_x.2xH₂O, which adopts a microporous three-dimensinal network structure (Zheng, et al., 2002). Limited studies of this anion suggest that the different binding modes arise from the manner in which the carboxy group is oriented with respect to the aromatic ring. However, functioning as a chelate, the phen ligand prevents the oligomeric compounds from adopting high dimensionality (Plater et al., 1999). This is noted in the present compound, which has a two-dimensional structure.

S2. Experimental

The title compound was synthesized using the hydrothermal method, from a mixture of 2,3-pyrazinedicarboxylic acid (1 mmol, 0.17 g), Eu(NO₃)₃·6H₂O (1 mmol, 0.45 g), 1,10-phenanthroline (3 mmol, 0.54 g) and water (20 ml) in a 30 ml Teflon-lined stainless steel reactor. The solution was heated at 432 K for 5 d. After the reaction system was cooled slowly to room temperature, colorless prismatic crystals were collected and washed with distilled water.

S3. Refinement

H atoms of water molecules were placed at idealized positions but were not refined; their U_iso(H) values were set at 1.2U_eq(O). Atom O2W is disordered over two sites, the occupancies of which were fixed at 0.5. A l l other H atoms were positioned geometrically and allowed to ride on their parent atoms at distances of 0.93 Å, with U_iso(H) values of 1.2U_eq(parent atom). The final difference Fourier map had a large peak near atom Eu1.

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: XP (Bruker, 2002); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The coordination environment of the independent cation in (I), with the atom-numbering scheme (displacement ellipsoids are shown at the 50% probability level).
	Fig. 2. The two-dimensional network of (I). H atoms, nitrate anions, water molecules and 1,10-phenanthroline molecules have been omitted for clarity.

Aqua-2,3-pyrazinedicarboxylate-nitrate-(1,10-phenanthroline)europium(III) monohydrate

Crystal data

[Eu(C6H2O4)(NO3)(C12H8N2)(H2O)]·H2O	F(000) = 1168
Mr = 596.30	Dx = 1.981 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4140 reflections
a = 12.3427 (3) Å	θ = 2.4–27.1°
b = 10.4806 (3) Å	µ = 3.20 mm^−1
c = 15.7966 (4) Å	T = 298 K
β = 101.947 (1)°	Prism, colorless
V = 1999.17 (9) Å^3	0.28 × 0.18 × 0.17 mm
Z = 4

Data collection

Bruker SMART APEX area-detector diffractometer	4497 independent reflections
Radiation source: fine-focus sealed tube	3676 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ϕ and ω scan	θmax = 27.5°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −14→15
Tmin = 0.468, Tmax = 0.612	k = −13→11
11996 measured reflections	l = −14→20

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.095	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0545P)^2] where P = (Fo^2 + 2Fc^2)/3
4497 reflections	(Δ/σ)max = 0.001
301 parameters	Δρmax = 1.65 e Å^−3
0 restraints	Δρmin = −0.82 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)
Eu1	0.667050 (18)	0.577623 (19)	0.633356 (13)	0.02142 (9)
O1	0.6656 (3)	0.7790 (3)	0.6956 (2)	0.0338 (8)
O2	0.6387 (3)	0.9166 (3)	0.7976 (2)	0.0399 (9)
O3	0.4351 (3)	0.8816 (3)	0.8781 (2)	0.0316 (7)
O4	0.5777 (3)	0.8828 (4)	0.9898 (2)	0.0450 (10)
O5	0.8561 (3)	0.5801 (3)	0.7304 (2)	0.0381 (9)
O6	0.7747 (3)	0.3975 (3)	0.7223 (2)	0.0351 (8)
O7	0.9392 (3)	0.4190 (3)	0.8027 (3)	0.0514 (11)
O1W	0.4650 (3)	0.6294 (4)	0.6255 (3)	0.0532 (11)
H1W1	0.4591	0.7068	0.6569	0.064*
H1W2	0.4306	0.5609	0.6508	0.064*
O2W	0.3504 (9)	0.6612 (9)	0.7435 (6)	0.077 (2)	0.50
H2W1	0.3204	0.6358	0.7933	0.093*	0.50
H2W2	0.3832	0.7300	0.7661	0.093*	0.50
O2W'	0.2642 (10)	0.6030 (9)	0.8223 (6)	0.077 (2)	0.50
H2W'	0.3204	0.6358	0.7933	0.093*	0.50
H2W"	0.2507	0.5242	0.8065	0.093*	0.50
N1	0.7733 (3)	0.4522 (4)	0.5357 (3)	0.0298 (9)
N2	0.7978 (3)	0.7092 (4)	0.5604 (2)	0.0314 (9)
N3	0.6249 (3)	0.5815 (3)	0.7877 (2)	0.0253 (8)
N4	0.5386 (4)	0.6093 (4)	0.9354 (3)	0.0374 (11)
N5	0.8594 (4)	0.4646 (4)	0.7530 (3)	0.0312 (9)
C1	0.7664 (5)	0.3262 (5)	0.5249 (4)	0.0405 (13)
H1	0.7320	0.2793	0.5618	0.049*
C2	0.8072 (5)	0.2607 (5)	0.4622 (4)	0.0486 (15)
H2	0.7997	0.1725	0.4570	0.058*
C3	0.8584 (5)	0.3275 (7)	0.4084 (4)	0.0546 (17)
H3	0.8861	0.2849	0.3657	0.065*
C4	0.8699 (4)	0.4602 (6)	0.4163 (4)	0.0429 (14)
C5	0.9218 (5)	0.5364 (7)	0.3612 (4)	0.0578 (17)
H5	0.9505	0.4975	0.3178	0.069*
C6	0.9296 (5)	0.6625 (7)	0.3712 (4)	0.0548 (17)
H6	0.9621	0.7100	0.3334	0.066*
C7	0.8893 (4)	0.7271 (6)	0.4387 (3)	0.0443 (14)
C8	0.9024 (5)	0.8576 (6)	0.4539 (4)	0.0487 (15)
H8	0.9368	0.9080	0.4188	0.058*
C9	0.8645 (5)	0.9100 (5)	0.5206 (5)	0.0512 (16)
H9	0.8726	0.9970	0.5315	0.061*
C10	0.8136 (5)	0.8336 (5)	0.5725 (4)	0.0415 (13)
H10	0.7891	0.8718	0.6183	0.050*
C11	0.8262 (4)	0.5184 (5)	0.4823 (3)	0.0305 (11)
C12	0.8379 (4)	0.6540 (5)	0.4943 (3)	0.0326 (11)
C13	0.6398 (4)	0.8080 (4)	0.7672 (3)	0.0261 (10)
C14	0.6072 (4)	0.6974 (4)	0.8169 (3)	0.0219 (9)
C15	0.5601 (4)	0.7107 (4)	0.8902 (3)	0.0263 (10)
C16	0.5598 (5)	0.4954 (5)	0.9060 (3)	0.0412 (14)
H16	0.5466	0.4232	0.9365	0.049*
C17	0.6008 (4)	0.4805 (5)	0.8320 (3)	0.0329 (11)
H17	0.6118	0.3988	0.8124	0.039*
C18	0.5229 (4)	0.8369 (4)	0.9212 (3)	0.0265 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Eu1	0.02926 (14)	0.02140 (14)	0.01505 (13)	−0.00164 (9)	0.00792 (9)	−0.00057 (9)
O1	0.056 (2)	0.0250 (17)	0.0262 (18)	−0.0036 (15)	0.0210 (16)	−0.0012 (14)
O2	0.065 (3)	0.0237 (19)	0.039 (2)	−0.0030 (15)	0.0270 (19)	−0.0077 (14)
O3	0.0324 (19)	0.0320 (17)	0.0296 (19)	0.0052 (15)	0.0045 (15)	−0.0030 (15)
O4	0.052 (2)	0.053 (2)	0.0238 (19)	0.0167 (19)	−0.0082 (17)	−0.0221 (17)
O5	0.040 (2)	0.038 (2)	0.034 (2)	−0.0041 (15)	0.0031 (17)	0.0049 (15)
O6	0.040 (2)	0.0292 (18)	0.036 (2)	−0.0014 (15)	0.0064 (16)	0.0015 (15)
O7	0.039 (2)	0.064 (3)	0.045 (3)	0.0093 (18)	−0.0036 (19)	0.0162 (19)
O1W	0.041 (2)	0.046 (2)	0.070 (3)	0.0055 (19)	0.005 (2)	−0.018 (2)
O2W	0.104 (6)	0.068 (4)	0.063 (5)	−0.013 (4)	0.024 (4)	−0.017 (4)
O2W'	0.104 (6)	0.068 (4)	0.063 (5)	−0.013 (4)	0.024 (4)	−0.017 (4)
N1	0.033 (2)	0.031 (2)	0.026 (2)	0.0023 (17)	0.0075 (18)	0.0025 (17)
N2	0.035 (2)	0.033 (2)	0.028 (2)	−0.0072 (18)	0.0084 (18)	0.0020 (17)
N3	0.031 (2)	0.027 (2)	0.0192 (19)	0.0016 (16)	0.0085 (16)	−0.0019 (15)
N4	0.057 (3)	0.035 (2)	0.027 (2)	0.007 (2)	0.024 (2)	0.0068 (18)
N5	0.034 (2)	0.040 (2)	0.022 (2)	0.0041 (19)	0.0100 (18)	0.0010 (18)
C1	0.044 (3)	0.036 (3)	0.041 (3)	0.003 (2)	0.007 (2)	0.001 (2)
C2	0.057 (4)	0.037 (3)	0.051 (4)	0.011 (3)	0.008 (3)	−0.011 (3)
C3	0.050 (4)	0.069 (4)	0.042 (3)	0.021 (3)	0.005 (3)	−0.019 (3)
C4	0.034 (3)	0.064 (4)	0.032 (3)	0.011 (3)	0.009 (2)	−0.006 (3)
C5	0.048 (4)	0.100 (5)	0.034 (3)	0.005 (4)	0.027 (3)	−0.003 (3)
C6	0.039 (3)	0.092 (5)	0.036 (3)	−0.006 (3)	0.015 (3)	0.014 (3)
C7	0.035 (3)	0.069 (4)	0.029 (3)	−0.005 (3)	0.007 (2)	0.015 (3)
C8	0.040 (3)	0.058 (4)	0.046 (4)	−0.018 (3)	0.004 (3)	0.026 (3)
C9	0.050 (4)	0.038 (3)	0.061 (4)	−0.018 (3)	0.002 (3)	0.012 (3)
C10	0.049 (3)	0.036 (3)	0.040 (3)	−0.016 (2)	0.011 (3)	−0.002 (2)
C11	0.027 (3)	0.045 (3)	0.021 (2)	0.004 (2)	0.0063 (19)	0.001 (2)
C12	0.028 (3)	0.044 (3)	0.024 (2)	−0.004 (2)	0.003 (2)	0.007 (2)
C13	0.033 (3)	0.026 (2)	0.021 (2)	0.0001 (19)	0.007 (2)	−0.0027 (18)
C14	0.027 (2)	0.021 (2)	0.016 (2)	0.0038 (17)	0.0030 (18)	−0.0007 (17)
C15	0.030 (3)	0.034 (3)	0.015 (2)	0.004 (2)	0.0070 (18)	−0.0001 (19)
C16	0.072 (4)	0.028 (3)	0.032 (3)	0.007 (3)	0.028 (3)	0.008 (2)
C17	0.054 (3)	0.021 (2)	0.028 (3)	0.006 (2)	0.019 (2)	0.002 (2)
C18	0.032 (3)	0.029 (2)	0.021 (2)	0.0038 (19)	0.012 (2)	−0.0005 (19)

Geometric parameters (Å, º)

Eu1—O1	2.331 (3)	N3—C17	1.335 (6)
Eu1—O4^i	2.344 (3)	N4—C16	1.326 (6)
Eu1—O3^ii	2.398 (3)	N4—C15	1.337 (6)
Eu1—O5	2.513 (4)	C1—C2	1.383 (7)
Eu1—O1W	2.530 (4)	C1—H1	0.9300
Eu1—O6	2.555 (3)	C2—C3	1.354 (8)
Eu1—N2	2.570 (4)	C2—H2	0.9300
Eu1—N1	2.582 (4)	C3—C4	1.401 (9)
Eu1—N3	2.597 (4)	C3—H3	0.9300
O1—C13	1.272 (5)	C4—C11	1.408 (7)
O2—C13	1.238 (5)	C4—C5	1.426 (8)
O3—C18	1.246 (5)	C5—C6	1.331 (10)
O3—Eu1^iii	2.398 (3)	C5—H5	0.9300
O4—C18	1.250 (6)	C6—C7	1.437 (8)
O4—Eu1^iv	2.344 (3)	C6—H6	0.9300
O5—N5	1.260 (5)	C7—C8	1.392 (8)
O6—N5	1.270 (5)	C7—C12	1.411 (6)
O7—N5	1.223 (6)	C8—C9	1.354 (9)
O1W—H1W1	0.96	C8—H8	0.9300
O1W—H1W2	0.96	C9—C10	1.386 (7)
O2W—H2W1	0.97	C9—H9	0.9300
O2W—H2W2	0.867	C10—H10	0.9300
O2W'—H2W'	0.97	C11—C12	1.437 (8)
O2W'—H2W"	0.87	C13—C14	1.501 (6)
N1—C1	1.332 (6)	C14—C15	1.406 (6)
N1—C11	1.360 (6)	C15—C18	1.514 (6)
N2—C10	1.327 (6)	C16—C17	1.376 (6)
N2—C12	1.372 (6)	C16—H16	0.9300
N3—C14	1.334 (5)	C17—H17	0.9300
O1—Eu1—O4^i	101.81 (13)	O7—N5—O6	121.2 (4)
O1—Eu1—O3^ii	139.30 (11)	O5—N5—O6	116.6 (4)
O4^i—Eu1—O3^ii	86.81 (12)	N1—C1—C2	124.1 (5)
O1—Eu1—O5	79.64 (12)	N1—C1—H1	117.9
O4^i—Eu1—O5	141.25 (13)	C2—C1—H1	117.9
O3^ii—Eu1—O5	117.52 (11)	C3—C2—C1	118.6 (6)
O1—Eu1—O1W	74.50 (12)	C3—C2—H2	120.7
O4^i—Eu1—O1W	69.71 (14)	C1—C2—H2	120.7
O3^ii—Eu1—O1W	71.50 (12)	C2—C3—C4	120.6 (5)
O5—Eu1—O1W	143.97 (13)	C2—C3—H3	119.7
O1—Eu1—O6	119.06 (11)	C4—C3—H3	119.7
O4^i—Eu1—O6	138.55 (13)	C3—C4—C11	116.7 (5)
O3^ii—Eu1—O6	67.28 (11)	C3—C4—C5	123.5 (5)
O5—Eu1—O6	50.27 (11)	C11—C4—C5	119.8 (6)
O1W—Eu1—O6	125.49 (13)	C6—C5—C4	121.0 (5)
O1—Eu1—N2	76.32 (12)	C6—C5—H5	119.5
O4^i—Eu1—N2	71.62 (12)	C4—C5—H5	119.5
O3^ii—Eu1—N2	142.69 (12)	C5—C6—C7	121.8 (5)
O5—Eu1—N2	71.21 (12)	C5—C6—H6	119.1
O1W—Eu1—N2	124.56 (14)	C7—C6—H6	119.1
O6—Eu1—N2	109.83 (12)	C8—C7—C12	118.5 (5)
O1—Eu1—N1	139.69 (12)	C8—C7—C6	123.0 (5)
O4^i—Eu1—N1	73.01 (14)	C12—C7—C6	118.4 (6)
O3^ii—Eu1—N1	80.96 (12)	C9—C8—C7	119.1 (5)
O5—Eu1—N1	81.23 (13)	C9—C8—H8	120.5
O1W—Eu1—N1	134.25 (13)	C7—C8—H8	120.5
O6—Eu1—N1	71.42 (12)	C8—C9—C10	119.9 (5)
N2—Eu1—N1	63.99 (13)	C8—C9—H9	120.1
O1—Eu1—N3	64.48 (11)	C10—C9—H9	120.1
O4^i—Eu1—N3	139.47 (14)	N2—C10—C9	123.6 (5)
O3^ii—Eu1—N3	83.08 (11)	N2—C10—H10	118.2
O5—Eu1—N3	76.57 (12)	C9—C10—H10	118.2
O1W—Eu1—N3	69.85 (13)	N1—C11—C4	123.0 (5)
O6—Eu1—N3	71.20 (11)	N1—C11—C12	118.1 (4)
N2—Eu1—N3	132.77 (12)	C4—C11—C12	118.9 (5)
N1—Eu1—N3	142.57 (12)	N2—C12—C7	121.6 (5)
C13—O1—Eu1	128.0 (3)	N2—C12—C11	118.4 (4)
C18—O3—Eu1^iii	138.4 (3)	C7—C12—C11	120.0 (5)
C18—O4—Eu1^iv	165.8 (4)	O2—C13—O1	126.1 (4)
N5—O5—Eu1	97.7 (3)	O2—C13—C14	118.7 (4)
N5—O6—Eu1	95.4 (3)	O1—C13—C14	115.1 (4)
Eu1—O1W—H1W1	109.6	N3—C14—C15	120.0 (4)
Eu1—O1W—H1W2	109.5	N3—C14—C13	116.2 (4)
H1W1—O1W—H1W2	109.3	C15—C14—C13	123.8 (4)
H2W1—O2W—H2W2	96.8	N4—C15—C14	121.5 (4)
H2W'—O2W'—H2W"	108.3	N4—C15—C18	114.5 (4)
C1—N1—C11	116.9 (4)	C14—C15—C18	123.9 (4)
C1—N1—Eu1	123.7 (3)	N4—C16—C17	122.2 (4)
C11—N1—Eu1	118.7 (3)	N4—C16—H16	118.9
C10—N2—C12	117.3 (4)	C17—C16—H16	118.9
C10—N2—Eu1	123.4 (3)	N3—C17—C16	121.1 (4)
C12—N2—Eu1	118.3 (3)	N3—C17—H17	119.5
C14—N3—C17	118.1 (4)	C16—C17—H17	119.5
C14—N3—Eu1	114.7 (3)	O3—C18—O4	125.7 (4)
C17—N3—Eu1	126.1 (3)	O3—C18—C15	116.0 (4)
C16—N4—C15	117.0 (4)	O4—C18—C15	118.1 (4)
O7—N5—O5	122.1 (4)

Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) −x+1, y−1/2, −z+3/2; (iii) −x+1, y+1/2, −z+3/2; (iv) x, −y+3/2, z+1/2.