Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199015851/bk1511sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270199015851/bk1511Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270199015851/bk1511IIsup3.hkl |
CCDC references: 143232; 143233
The reaction of Pr2O3 and Nd2O3 with excess oxydiacetic acid in water (1:7:100) and subsequent work-up afforded light-green crystals of (I) and light-blue crystals of (II) in good yields. The procedure has been described previously in detail (Baggio et al., 1996). The IR spectra of the two compounds show significant changes in the COOH range. In fact the IR spectrum of compound (II) shows the characteristic absorptions of the acyd carbonyl groups (1738–1683 cm-1) in addition to the bands of the carboxylate anions (1597 and 1445 cm-1) and water molecules (~1641 and ~3550–3400 cm-1) also observed for compound (I). TGA measurements show that both compounds lose almost exactly eight water molecules per formula unit well below 450 K.
All chemicals were of reagent-grade purity and used as received. Water was purified by a Millipore milli-Q system. Elemental analyses (C,H) were performed on a Carlo Erba EA 1108 instrument. Infrared spectra were recorded as KBr discs with a Nicolet 510P FT—IR spectrophotometer. Thermogravimetric analyses were recorded on a Shimadzu DTG50 thermal analyzer under an atmosphere of air at a heating rate of 5 K min-1.
In both structures some hydration water molecules appeared split in a number of sites of lower occupancy, turning thus difficult to assess their correct total number just from the X-ray data alone. They were accordingly refined with adjustable populations constrained to add up to the value given by the thermogravimetric analysis, and a unique, common isotropic displacement factor.
As the H atoms could not be found in the difference Fourier synthesis, only those attached to carbon were included in ideallized positions, and refined using a riding scheme, both in coordinates as in displacement factors.
For both compounds, data collection: P3/P4-PC (Siemens, 1991); cell refinement: P3/P4-PC. Data reduction: XDISK in SHELXTL/PC (Sheldrick, 1991) for (I); XDISK in SHELXTL/PC (Sheldrick,1991) for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b). Molecular graphics: XP in SHELXTL/PC for (I); XP in SHELXTL/PC (Sheldrick, 1991) for (II). For both compounds, software used to prepare material for publication: CIFTAB (Sheldrick, 1993), PARST (Nardelli, 1983) and CSD (Allen et al., 1983).
[Pr2(C4H4O5)3(H2O)3]·5H2O | Dx = 2.06 Mg m−3 |
Mr = 822.16 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, P62c | Cell parameters from 25 reflections |
a = 9.4003 (12) Å | θ = 7.5–12.5° |
c = 17.350 (4) Å | µ = 3.72 mm−1 |
V = 1327.8 (4) Å3 | T = 293 K |
Z = 2 | Prisms, light green |
F(000) = 804 | 0.35 × 0.15 × 0.14 mm |
Siemens R3m diffractometer | 738 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.034 |
Graphite monochromator | θmax = 25.0°, θmin = 2.4° |
ω/2θ scans | h = −11→0 |
Absorption correction: ψ-scan (XEMP in SHELXTL/PC; Sheldrick, 1991) | k = 0→11 |
Tmin = 0.35, Tmax = 0.60 | l = 0→20 |
1693 measured reflections | 2 standard reflections every 98 reflections |
780 independent reflections | intensity decay: <2% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: C-H:geom O-H:not found |
R[F2 > 2σ(F2)] = 0.020 | H-atom parameters constrained |
wR(F2) = 0.059 | Calculated w = 1/[σ2(Fo2) + (0.031P)2 + 2.733P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.01 |
780 reflections | Δρmax = 0.94 e Å−3 |
63 parameters | Δρmin = −0.87 e Å−3 |
0 restraints | Absolute structure: Flack (1983) |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.02 (4) |
[Pr2(C4H4O5)3(H2O)3]·5H2O | Z = 2 |
Mr = 822.16 | Mo Kα radiation |
Hexagonal, P62c | µ = 3.72 mm−1 |
a = 9.4003 (12) Å | T = 293 K |
c = 17.350 (4) Å | 0.35 × 0.15 × 0.14 mm |
V = 1327.8 (4) Å3 |
Siemens R3m diffractometer | 738 reflections with I > 2σ(I) |
Absorption correction: ψ-scan (XEMP in SHELXTL/PC; Sheldrick, 1991) | Rint = 0.034 |
Tmin = 0.35, Tmax = 0.60 | 2 standard reflections every 98 reflections |
1693 measured reflections | intensity decay: <2% |
780 independent reflections |
R[F2 > 2σ(F2)] = 0.020 | H-atom parameters constrained |
wR(F2) = 0.059 | Δρmax = 0.94 e Å−3 |
S = 1.08 | Δρmin = −0.87 e Å−3 |
780 reflections | Absolute structure: Flack (1983) |
63 parameters | Absolute structure parameter: −0.02 (4) |
0 restraints |
Refinement. The structure was solved by direct methods and refined on F2, with anisotropic displacement factors for all non-H atoms with full occupancy. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Pr1 | 0.6667 | 0.3333 | 0.2500 | 0.01639 (16) | |
Pr2 | 0.0000 | 0.0000 | 0.0000 | 0.01481 (16) | |
O1 | 0.2108 (5) | 0.1722 (5) | 0.0965 (2) | 0.0321 (9) | |
O2 | 0.4473 (5) | 0.2704 (5) | 0.1572 (2) | 0.0384 (10) | |
O3 | 0.2715 (6) | 0.0000 | 0.0000 | 0.0299 (14) | |
C1 | 0.3484 (5) | 0.1825 (14) | 0.1061 (2) | 0.0268 (11) | |
C2 | 0.4000 (8) | 0.0929 (9) | 0.0534 (4) | 0.0442 (17) | |
H2A | 0.4985 | 0.1703 | 0.0259 | 0.053* | |
H2B | 0.4246 | 0.0201 | 0.0828 | 0.053* | |
O1W | 0.5625 (9) | 0.5502 (9) | 0.2500 | 0.056 (2) | |
O2WA | 0.158 (3) | 0.285 (2) | 0.2500 | 0.098 (4)* | 0.692 (17) |
O2WB | 0.082 (6) | 0.180 (4) | 0.2500 | 0.098 (4)* | 0.352 (17) |
O2WC | 0.226 (3) | −0.296 (3) | 0.1299 (11) | 0.098 (4)* | 0.311 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pr1 | 0.02006 (19) | 0.02006 (19) | 0.0090 (2) | 0.01003 (10) | 0.000 | 0.000 |
Pr2 | 0.01558 (19) | 0.01558 (19) | 0.0133 (3) | 0.00779 (9) | 0.000 | 0.000 |
O1 | 0.026 (2) | 0.041 (2) | 0.032 (2) | 0.0186 (18) | −0.0129 (18) | −0.0171 (18) |
O2 | 0.037 (2) | 0.042 (2) | 0.036 (2) | 0.0195 (19) | −0.019 (2) | −0.0143 (19) |
O3 | 0.022 (2) | 0.043 (4) | 0.032 (3) | 0.0216 (18) | −0.0098 (13) | −0.020 (3) |
C1 | 0.024 (2) | 0.034 (4) | 0.021 (2) | 0.014 (3) | −0.0084 (18) | −0.004 (4) |
C2 | 0.030 (3) | 0.060 (4) | 0.052 (4) | 0.029 (3) | −0.022 (3) | −0.033 (4) |
O1W | 0.066 (5) | 0.037 (4) | 0.064 (4) | 0.025 (4) | 0.000 | 0.000 |
Pr1—O2i | 2.444 (4) | Pr2—O1viii | 2.478 (4) |
Pr1—O2ii | 2.444 (4) | Pr2—O1ix | 2.478 (4) |
Pr1—O2iii | 2.444 (4) | Pr2—O1x | 2.478 (4) |
Pr1—O2iv | 2.444 (4) | Pr2—O3x | 2.552 (5) |
Pr1—O2 | 2.444 (4) | Pr2—O3 | 2.552 (5) |
Pr1—O2v | 2.444 (4) | Pr2—O3ix | 2.552 (5) |
Pr1—O1Wiv | 2.666 (7) | O1—C1 | 1.259 (7) |
Pr1—O1Wi | 2.666 (7) | O2—C1 | 1.251 (7) |
Pr1—O1W | 2.666 (7) | O3—C2 | 1.423 (6) |
Pr2—O1 | 2.478 (4) | O3—C2vii | 1.423 (6) |
Pr2—O1vi | 2.478 (4) | C1—C2 | 1.480 (11) |
Pr2—O1vii | 2.478 (4) | ||
O1···O2WA | 2.99 (1) | O1W···O2WAxi | 2.63 (2) |
O1···O2WB | 2.94 (2) | O1W···O2WBxi | 2.96 (3) |
O2i—Pr1—O2ii | 82.4 (2) | O1vii—Pr2—O1viii | 79.36 (15) |
O2i—Pr1—O2iii | 135.79 (7) | O1—Pr2—O1ix | 79.36 (15) |
O2ii—Pr1—O2iii | 81.34 (15) | O1vi—Pr2—O1ix | 86.9 (2) |
O2i—Pr1—O2iv | 81.34 (15) | O1vii—Pr2—O1ix | 150.66 (18) |
O2ii—Pr1—O2iv | 135.79 (7) | O1viii—Pr2—O1ix | 123.54 (17) |
O2iii—Pr1—O2iv | 82.4 (2) | O1—Pr2—O1x | 79.36 (15) |
O2i—Pr1—O2 | 81.34 (15) | O1vi—Pr2—O1x | 123.54 (17) |
O2ii—Pr1—O2 | 135.79 (7) | O1vii—Pr2—O1x | 86.9 (2) |
O2iii—Pr1—O2 | 135.79 (7) | O1viii—Pr2—O1x | 150.66 (19) |
O2iv—Pr1—O2 | 81.34 (15) | O1ix—Pr2—O1x | 79.36 (15) |
O2i—Pr1—O2v | 135.79 (7) | O1—Pr2—O3x | 136.57 (10) |
O2ii—Pr1—O2v | 81.34 (15) | O1vi—Pr2—O3x | 61.77 (9) |
O2iii—Pr1—O2v | 81.34 (15) | O1vii—Pr2—O3x | 75.33 (9) |
O2iv—Pr1—O2v | 135.79 (7) | O1viii—Pr2—O3x | 136.57 (10) |
O2—Pr1—O2v | 82.4 (2) | O1ix—Pr2—O3x | 75.33 (9) |
O2i—Pr1—O1Wiv | 69.57 (15) | O1x—Pr2—O3x | 61.77 (9) |
O2ii—Pr1—O1Wiv | 69.57 (15) | O1—Pr2—O3 | 61.77 (9) |
O2iii—Pr1—O1Wiv | 66.24 (15) | O1vi—Pr2—O3 | 136.57 (10) |
O2iv—Pr1—O1Wiv | 66.24 (15) | O1vii—Pr2—O3 | 61.77 (9) |
O2—Pr1—O1Wiv | 138.76 (10) | O1viii—Pr2—O3 | 75.33 (9) |
O2v—Pr1—O1Wiv | 138.76 (10) | O1ix—Pr2—O3 | 136.57 (10) |
O2i—Pr1—O1Wi | 66.24 (15) | O1x—Pr2—O3 | 75.33 (9) |
O2ii—Pr1—O1Wi | 66.24 (15) | O3x—Pr2—O3 | 120.0 |
O2iii—Pr1—O1Wi | 138.76 (10) | O1—Pr2—O3ix | 75.33 (9) |
O2iv—Pr1—O1Wi | 138.76 (10) | O1vi—Pr2—O3ix | 75.33 (9) |
O2—Pr1—O1Wi | 69.57 (15) | O1vii—Pr2—O3ix | 136.57 (10) |
O2v—Pr1—O1Wi | 69.57 (15) | O1viii—Pr2—O3ix | 61.77 (9) |
O1Wiv—Pr1—O1Wi | 120.0 | O1ix—Pr2—O3ix | 61.77 (9) |
O2i—Pr1—O1W | 138.76 (10) | O1x—Pr2—O3ix | 136.57 (10) |
O2ii—Pr1—O1W | 138.76 (10) | O3x—Pr2—O3ix | 120.0 |
O2iii—Pr1—O1W | 69.57 (15) | O3—Pr2—O3ix | 120.0 |
O2iv—Pr1—O1W | 69.57 (15) | C1—O1—Pr2 | 126.5 (5) |
O2—Pr1—O1W | 66.24 (15) | C1—O2—Pr1 | 152.3 (6) |
O2v—Pr1—O1W | 66.24 (15) | C2—O3—C2vii | 114.4 (6) |
O1Wiv—Pr1—O1W | 120.000 (2) | C2—O3—Pr2 | 122.8 (3) |
O1Wi—Pr1—O1W | 120.000 (2) | C2vii—O3—Pr2 | 122.8 (3) |
O1—Pr2—O1vi | 150.66 (19) | O2—C1—O1 | 122.7 (9) |
O1—Pr2—O1vii | 123.54 (17) | O2—C1—C2 | 117.8 (6) |
O1vi—Pr2—O1vii | 79.36 (15) | O1—C1—C2 | 119.4 (5) |
O1—Pr2—O1viii | 86.9 (2) | O3—C2—C1 | 109.4 (4) |
O1vi—Pr2—O1viii | 79.36 (15) |
Symmetry codes: (i) −y+1, x−y, z; (ii) −y+1, x−y, −z+1/2; (iii) −x+y+1, −x+1, −z+1/2; (iv) −x+y+1, −x+1, z; (v) x, y, −z+1/2; (vi) −x, −x+y, −z; (vii) x−y, −y, −z; (viii) y, x, −z; (ix) −y, x−y, z; (x) −x+y, −x, z; (xi) −y+1, x−y+1, z. |
[Nd2(C4H4O5)3(H2O)6]·2H2O·C4H6O5 | F(000) = 1896 |
Mr = 962.91 | Dx = 2.09 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 14.096 (2) Å | Cell parameters from 25 reflections |
b = 6.844 (1) Å | θ = 7.5–15° |
c = 32.223 (3) Å | µ = 3.46 mm−1 |
β = 99.59 (1)° | T = 293 K |
V = 3065.1 (6) Å3 | Plates, light blue |
Z = 4 | 0.36 × 0.24 × 0.10 mm |
Siemens R3m diffractometer | 3568 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.040 |
Graphite monochromator | θmax = 25.0°, θmin = 1.7° |
ω/2θ scans | h = 0→16 |
Absorption correction: ψ-scan (XEMP in SHELXTL/PC, Sheldrick, 1991) | k = 0→8 |
Tmin = 0.38, Tmax = 0.70 | l = −38→37 |
5674 measured reflections | 2 standard reflections every 98 reflections |
5393 independent reflections | intensity decay: <2% |
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)] = 0.047 | Hydrogen site location: C-H:geom O-H:not found |
wR(F2) = 0.145 | H-atom parameters constrained |
S = 1.03 | Calculated w = 1/[σ2(Fo2) + (0.065P)2 + 37.22P] where P = (Fo2 + 2Fc2)/3 |
5393 reflections | (Δ/σ)max < 0.01 |
419 parameters | Δρmax = 0.77 e Å−3 |
1 restraint | Δρmin = −0.89 e Å−3 |
[Nd2(C4H4O5)3(H2O)6]·2H2O·C4H6O5 | V = 3065.1 (6) Å3 |
Mr = 962.91 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 14.096 (2) Å | µ = 3.46 mm−1 |
b = 6.844 (1) Å | T = 293 K |
c = 32.223 (3) Å | 0.36 × 0.24 × 0.10 mm |
β = 99.59 (1)° |
Siemens R3m diffractometer | 3568 reflections with I > 2σ(I) |
Absorption correction: ψ-scan (XEMP in SHELXTL/PC, Sheldrick, 1991) | Rint = 0.040 |
Tmin = 0.38, Tmax = 0.70 | 2 standard reflections every 98 reflections |
5674 measured reflections | intensity decay: <2% |
5393 independent reflections |
R[F2 > 2σ(F2)] = 0.047 | 1 restraint |
wR(F2) = 0.145 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.77 e Å−3 |
5393 reflections | Δρmin = −0.89 e Å−3 |
419 parameters |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Nd1 | 0.01488 (4) | 0.55193 (9) | 0.138457 (16) | 0.01857 (17) | |
Nd2 | −0.02898 (4) | 0.55690 (9) | 0.328610 (16) | 0.01806 (16) | |
O11 | 0.1722 (5) | 0.4571 (12) | 0.1783 (3) | 0.0306 (18) | |
O21 | 0.3244 (6) | 0.5260 (12) | 0.2050 (3) | 0.034 (2) | |
O31 | 0.1170 (5) | 0.8153 (11) | 0.1822 (3) | 0.0298 (19) | |
O41 | −0.0347 (5) | 1.2212 (11) | 0.1540 (3) | 0.031 (2) | |
O51 | −0.0383 (6) | 0.9094 (11) | 0.1321 (3) | 0.032 (2) | |
C11 | 0.2384 (7) | 0.5720 (17) | 0.1940 (3) | 0.024 (2) | |
C21 | 0.2138 (7) | 0.7810 (16) | 0.2005 (3) | 0.023 (2) | |
H21A | 0.2229 | 0.8099 | 0.2304 | 0.028* | |
H21B | 0.2560 | 0.8655 | 0.1877 | 0.028* | |
C31 | 0.0847 (8) | 1.0095 (15) | 0.1872 (4) | 0.029 (3) | |
H31A | 0.1351 | 1.1011 | 0.1835 | 0.035* | |
H31B | 0.0706 | 1.0260 | 0.2155 | 0.035* | |
C41 | −0.0037 (8) | 1.0514 (17) | 0.1557 (4) | 0.027 (2) | |
O12 | −0.1031 (5) | 0.5532 (14) | 0.0750 (2) | 0.0337 (19) | |
O22 | −0.2494 (5) | 0.5768 (15) | 0.0373 (2) | 0.040 (2) | |
O32 | −0.1608 (5) | 0.5670 (12) | 0.1461 (2) | 0.0233 (16) | |
O42 | −0.1211 (5) | 0.5717 (13) | 0.2570 (2) | 0.0313 (19) | |
O52 | −0.0243 (5) | 0.5780 (13) | 0.2095 (2) | 0.0296 (18) | |
C12 | −0.1928 (7) | 0.5627 (17) | 0.0716 (3) | 0.024 (2) | |
C22 | −0.2364 (7) | 0.5512 (19) | 0.1107 (3) | 0.026 (2) | |
H22A | −0.2823 | 0.6563 | 0.1111 | 0.031* | |
H22B | −0.2698 | 0.4278 | 0.1116 | 0.031* | |
C32 | −0.1941 (7) | 0.5595 (19) | 0.1856 (3) | 0.027 (2) | |
H32A | −0.2294 | 0.4393 | 0.1878 | 0.032* | |
H32B | −0.2367 | 0.6688 | 0.1881 | 0.032* | |
C42 | −0.1074 (7) | 0.5688 (18) | 0.2202 (4) | 0.029 (3) | |
O13 | 0.1307 (5) | 0.4609 (11) | 0.3665 (2) | 0.0292 (18) | |
O23 | 0.2822 (5) | 0.5262 (12) | 0.3953 (3) | 0.041 (2) | |
O33 | 0.0768 (5) | 0.8191 (10) | 0.3705 (2) | 0.0241 (17) | |
O43 | −0.0739 (5) | 1.2220 (10) | 0.3407 (2) | 0.0249 (17) | |
O53 | −0.0804 (6) | 0.9045 (11) | 0.3228 (2) | 0.0303 (19) | |
C13 | 0.1969 (8) | 0.5731 (17) | 0.3838 (4) | 0.026 (2) | |
C23 | 0.1721 (7) | 0.7805 (16) | 0.3927 (4) | 0.026 (3) | |
H23A | 0.1743 | 0.7990 | 0.4227 | 0.031* | |
H23B | 0.2178 | 0.8691 | 0.3833 | 0.031* | |
C33 | 0.0466 (8) | 1.0128 (16) | 0.3758 (4) | 0.027 (3) | |
H33A | 0.0965 | 1.1040 | 0.3712 | 0.033* | |
H33B | 0.0336 | 1.0313 | 0.4042 | 0.033* | |
C43 | −0.0440 (8) | 1.0480 (16) | 0.3441 (3) | 0.024 (2) | |
O14 | 0.0490 (6) | 0.7483 (14) | 0.4739 (3) | 0.039 (2) | |
O24 | 0.0752 (6) | 0.8449 (14) | 0.5417 (2) | 0.040 (2) | |
O34 | −0.1322 (5) | 0.6445 (13) | 0.4795 (2) | 0.034 (2) | |
O44 | −0.3728 (6) | 0.5164 (14) | 0.4413 (3) | 0.042 (2) | |
O54 | −0.2438 (6) | 0.5228 (16) | 0.4115 (3) | 0.047 (3) | |
C14 | 0.0228 (8) | 0.7707 (17) | 0.5075 (4) | 0.029 (3) | |
C24 | −0.0788 (8) | 0.7265 (18) | 0.5162 (3) | 0.031 (3) | |
H24A | −0.0756 | 0.6356 | 0.5395 | 0.037* | |
H24B | −0.1093 | 0.8458 | 0.5236 | 0.037* | |
C34 | −0.2268 (8) | 0.592 (2) | 0.4851 (4) | 0.035 (3) | |
H34A | −0.2572 | 0.7001 | 0.4973 | 0.042* | |
H34B | −0.2250 | 0.4802 | 0.5036 | 0.042* | |
C44 | −0.2815 (8) | 0.5436 (17) | 0.4419 (4) | 0.028 (2) | |
O1W | 0.1194 (8) | 0.7023 (15) | 0.0933 (3) | 0.062 (3) | |
O2W | 0.0736 (6) | 0.3002 (12) | 0.0895 (3) | 0.035 (2) | |
O3W | 0.0332 (6) | 0.2991 (13) | 0.2769 (3) | 0.040 (2) | |
O4W | 0.0845 (6) | 0.6921 (13) | 0.2847 (2) | 0.034 (2) | |
O5W | −0.0583 (6) | 0.5854 (14) | 0.4016 (2) | 0.040 (2) | |
O6W | −0.2106 (5) | 0.5591 (13) | 0.3277 (2) | 0.0313 (18) | |
O7W | −0.3629 (7) | 0.5492 (17) | 0.2626 (3) | 0.054 (3) | |
O8WA | 0.1342 (16) | 0.514 (3) | 0.0209 (7) | 0.062 (5)* | 0.456 (10) |
O8WB | 0.003 (3) | 0.832 (6) | 0.0015 (12) | 0.062 (5)* | 0.303 (10) |
O8WC | −0.029 (3) | 0.741 (7) | −0.0015 (14) | 0.062 (5)* | 0.241 (10) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Nd1 | 0.0174 (3) | 0.0188 (3) | 0.0194 (3) | 0.0005 (3) | 0.0028 (2) | −0.0006 (3) |
Nd2 | 0.0191 (3) | 0.0172 (3) | 0.0178 (3) | −0.0008 (3) | 0.0030 (2) | −0.0004 (3) |
O11 | 0.023 (4) | 0.019 (4) | 0.047 (5) | 0.002 (4) | −0.002 (4) | −0.007 (4) |
O21 | 0.029 (4) | 0.023 (4) | 0.047 (5) | 0.002 (4) | −0.004 (4) | −0.006 (4) |
O31 | 0.022 (4) | 0.019 (4) | 0.043 (5) | 0.002 (3) | −0.008 (4) | −0.007 (4) |
O41 | 0.028 (4) | 0.014 (4) | 0.053 (6) | 0.003 (3) | 0.010 (4) | 0.001 (4) |
O51 | 0.031 (4) | 0.025 (5) | 0.039 (5) | 0.003 (4) | −0.002 (4) | 0.001 (4) |
C11 | 0.021 (5) | 0.028 (6) | 0.022 (5) | 0.002 (5) | −0.001 (4) | 0.005 (5) |
C21 | 0.020 (5) | 0.025 (6) | 0.022 (6) | 0.002 (5) | −0.001 (4) | −0.006 (5) |
C31 | 0.034 (6) | 0.015 (6) | 0.035 (7) | 0.011 (5) | −0.006 (5) | −0.013 (5) |
C41 | 0.026 (6) | 0.019 (6) | 0.040 (7) | −0.006 (5) | 0.017 (5) | 0.007 (6) |
O12 | 0.026 (4) | 0.051 (5) | 0.025 (4) | 0.008 (4) | 0.005 (3) | 0.003 (4) |
O22 | 0.025 (4) | 0.068 (7) | 0.024 (4) | 0.004 (4) | 0.000 (3) | −0.007 (5) |
O32 | 0.020 (3) | 0.037 (4) | 0.012 (3) | 0.005 (4) | 0.000 (3) | −0.003 (4) |
O42 | 0.025 (4) | 0.051 (5) | 0.017 (4) | −0.002 (4) | 0.001 (3) | −0.006 (4) |
O52 | 0.023 (4) | 0.048 (5) | 0.019 (4) | 0.003 (4) | 0.007 (3) | −0.003 (4) |
C12 | 0.026 (6) | 0.027 (6) | 0.019 (5) | −0.003 (5) | −0.001 (4) | −0.004 (5) |
C22 | 0.018 (5) | 0.033 (6) | 0.026 (6) | 0.006 (5) | −0.002 (4) | 0.000 (6) |
C32 | 0.022 (5) | 0.036 (6) | 0.022 (6) | −0.004 (5) | 0.006 (4) | −0.004 (6) |
C42 | 0.021 (5) | 0.031 (6) | 0.033 (7) | 0.001 (5) | 0.000 (5) | −0.001 (6) |
O13 | 0.031 (4) | 0.017 (4) | 0.037 (5) | 0.004 (4) | −0.003 (3) | −0.003 (4) |
O23 | 0.021 (4) | 0.029 (5) | 0.069 (7) | 0.006 (4) | −0.005 (4) | −0.002 (5) |
O33 | 0.023 (4) | 0.015 (4) | 0.032 (4) | 0.005 (3) | −0.001 (3) | −0.005 (3) |
O43 | 0.027 (4) | 0.015 (4) | 0.034 (5) | −0.008 (3) | 0.010 (3) | 0.000 (3) |
O53 | 0.038 (4) | 0.026 (5) | 0.024 (4) | 0.001 (4) | −0.002 (4) | −0.006 (4) |
C13 | 0.024 (6) | 0.027 (6) | 0.029 (6) | 0.002 (5) | 0.006 (5) | 0.006 (5) |
C23 | 0.021 (5) | 0.021 (6) | 0.033 (6) | −0.005 (5) | −0.001 (5) | −0.001 (5) |
C33 | 0.026 (6) | 0.021 (6) | 0.035 (7) | 0.003 (5) | 0.004 (5) | −0.002 (5) |
C43 | 0.033 (6) | 0.013 (5) | 0.026 (6) | −0.003 (5) | 0.008 (5) | 0.010 (5) |
O14 | 0.036 (5) | 0.054 (6) | 0.025 (5) | −0.001 (4) | 0.002 (4) | −0.004 (4) |
O24 | 0.037 (5) | 0.057 (6) | 0.023 (4) | −0.008 (4) | −0.002 (4) | −0.011 (4) |
O34 | 0.027 (4) | 0.052 (5) | 0.022 (4) | −0.012 (4) | 0.003 (3) | −0.016 (4) |
O44 | 0.032 (5) | 0.054 (6) | 0.040 (5) | −0.003 (4) | 0.005 (4) | −0.007 (4) |
O54 | 0.037 (5) | 0.081 (8) | 0.021 (4) | −0.011 (5) | 0.000 (4) | −0.010 (5) |
C14 | 0.033 (6) | 0.028 (6) | 0.022 (7) | −0.003 (5) | −0.010 (5) | 0.002 (5) |
C24 | 0.038 (7) | 0.036 (7) | 0.018 (6) | −0.007 (6) | 0.000 (5) | 0.002 (5) |
C34 | 0.036 (7) | 0.045 (8) | 0.025 (6) | −0.007 (6) | 0.006 (5) | −0.005 (6) |
C44 | 0.033 (6) | 0.022 (6) | 0.030 (6) | −0.004 (5) | 0.003 (5) | 0.004 (6) |
O1W | 0.078 (7) | 0.052 (6) | 0.068 (7) | −0.033 (6) | 0.047 (6) | −0.021 (6) |
O2W | 0.041 (5) | 0.032 (5) | 0.034 (5) | 0.015 (4) | 0.012 (4) | −0.003 (4) |
O3W | 0.035 (5) | 0.038 (5) | 0.047 (5) | 0.003 (4) | 0.010 (4) | 0.001 (4) |
O4W | 0.034 (4) | 0.046 (5) | 0.024 (4) | −0.012 (4) | 0.011 (4) | −0.001 (4) |
O5W | 0.041 (5) | 0.063 (6) | 0.020 (4) | −0.015 (5) | 0.015 (4) | −0.009 (4) |
O6W | 0.025 (4) | 0.039 (5) | 0.029 (4) | 0.006 (4) | 0.002 (3) | −0.008 (4) |
O7W | 0.053 (6) | 0.069 (7) | 0.035 (5) | 0.012 (6) | −0.007 (4) | −0.008 (5) |
Nd1—O12 | 2.412 (7) | C31—C41 | 1.499 (16) |
Nd1—O41i | 2.445 (8) | O12—C12 | 1.253 (12) |
Nd1—O52 | 2.448 (7) | O22—C12 | 1.256 (12) |
Nd1—O11 | 2.457 (7) | O32—C32 | 1.430 (12) |
Nd1—O1W | 2.462 (9) | O32—C22 | 1.430 (12) |
Nd1—O32 | 2.531 (7) | O42—C42 | 1.233 (13) |
Nd1—O51 | 2.557 (8) | O52—C42 | 1.276 (13) |
Nd1—O2W | 2.566 (8) | C12—C22 | 1.491 (15) |
Nd1—O31 | 2.575 (7) | C32—C42 | 1.512 (14) |
Nd2—O43i | 2.426 (7) | O13—C13 | 1.264 (13) |
Nd2—O42 | 2.455 (7) | O23—C13 | 1.240 (13) |
Nd2—O13 | 2.463 (7) | O33—C33 | 1.412 (12) |
Nd2—O5W | 2.464 (7) | O33—C23 | 1.437 (12) |
Nd2—O53 | 2.485 (8) | O43—C43 | 1.262 (13) |
Nd2—O4W | 2.485 (8) | O53—C43 | 1.257 (13) |
Nd2—O6W | 2.555 (7) | C13—C23 | 1.501 (15) |
Nd2—O33 | 2.568 (7) | C33—C43 | 1.516 (15) |
Nd2—O3W | 2.674 (9) | O14—C14 | 1.208 (14) |
O11—C11 | 1.260 (13) | O24—C14 | 1.322 (13) |
O21—C11 | 1.246 (13) | O34—C24 | 1.409 (13) |
O31—C21 | 1.415 (12) | O34—C34 | 1.421 (13) |
O31—C31 | 1.423 (12) | O44—C44 | 1.298 (14) |
O41—C41 | 1.239 (14) | O54—C44 | 1.200 (14) |
O51—C41 | 1.280 (14) | C14—C24 | 1.536 (16) |
C11—C21 | 1.494 (15) | C34—C44 | 1.511 (16) |
O1W···O23ii | 2.61 (1) | O4W···O52 | 2.76 (1) |
O1W···O8WA | 2.70 (3) | O5W···O14 | 2.79 (1) |
O2W···O41i | 2.83 (1) | O5W···O34 | 2.90 (1) |
O2W···O23iii | 2.75 (1) | O5W···O54 | 2.72 (1) |
O2W···O8WA | 2.89 (3) | O6W···O43i | 2.99 (1) |
O2W···O8WCiv | 2.81 (2) | O6W···O7W | 2.74 (1) |
O3W···O21iii | 2.73 (1) | O7W···O53v | 2.91 (1) |
O3W···O43i | 2.79 (1) | O8WA···O22iv | 2.74 (2) |
O3W···O52 | 2.90 (1) | O24···O22vi | 2.55 (1) |
O4W···O21ii | 2.61 (1) | O44···O51v | 2.59 (1) |
O12—Nd1—O41i | 89.8 (3) | O4W—Nd2—O33 | 70.5 (3) |
O12—Nd1—O52 | 124.2 (2) | O6W—Nd2—O33 | 119.7 (2) |
O41i—Nd1—O52 | 76.1 (3) | O43i—Nd2—O3W | 66.3 (3) |
O12—Nd1—O11 | 151.5 (3) | O42—Nd2—O3W | 67.5 (3) |
O41i—Nd1—O11 | 85.0 (3) | O13—Nd2—O3W | 76.4 (3) |
O52—Nd1—O11 | 81.7 (3) | O5W—Nd2—O3W | 140.6 (3) |
O12—Nd1—O1W | 83.8 (3) | O53—Nd2—O3W | 135.0 (3) |
O41i—Nd1—O1W | 136.7 (3) | O4W—Nd2—O3W | 65.2 (3) |
O52—Nd1—O1W | 140.6 (3) | O6W—Nd2—O3W | 115.4 (3) |
O11—Nd1—O1W | 81.0 (3) | O33—Nd2—O3W | 124.5 (2) |
O12—Nd1—O32 | 62.3 (2) | C11—O11—Nd1 | 126.0 (7) |
O41i—Nd1—O32 | 72.6 (3) | C21—O31—C31 | 114.3 (8) |
O52—Nd1—O32 | 61.9 (2) | C21—O31—Nd1 | 121.7 (6) |
O11—Nd1—O32 | 140.5 (3) | C31—O31—Nd1 | 123.8 (6) |
O1W—Nd1—O32 | 137.1 (3) | C41—O41—Nd1vii | 140.0 (7) |
O12—Nd1—O51 | 77.1 (3) | C41—O51—Nd1 | 127.0 (7) |
O41i—Nd1—O51 | 144.3 (3) | O21—C11—O11 | 125.2 (11) |
O52—Nd1—O51 | 84.0 (3) | O21—C11—C21 | 116.0 (10) |
O11—Nd1—O51 | 121.4 (3) | O11—C11—C21 | 118.7 (9) |
O1W—Nd1—O51 | 75.5 (3) | O31—C21—C11 | 109.3 (8) |
O32—Nd1—O51 | 72.0 (3) | O31—C31—C41 | 110.3 (9) |
O12—Nd1—O2W | 74.2 (3) | O41—C41—O51 | 126.1 (11) |
O41i—Nd1—O2W | 68.7 (3) | O41—C41—C31 | 117.2 (10) |
O52—Nd1—O2W | 140.4 (3) | O51—C41—C31 | 116.7 (10) |
O11—Nd1—O2W | 77.8 (3) | C12—O12—Nd1 | 128.0 (7) |
O1W—Nd1—O2W | 68.3 (3) | C32—O32—C22 | 113.4 (8) |
O32—Nd1—O2W | 120.6 (3) | C32—O32—Nd1 | 123.9 (6) |
O51—Nd1—O2W | 135.5 (3) | C22—O32—Nd1 | 122.0 (6) |
O12—Nd1—O31 | 134.8 (3) | C42—O42—Nd2 | 139.5 (7) |
O41i—Nd1—O31 | 133.5 (3) | C42—O52—Nd1 | 127.6 (7) |
O52—Nd1—O31 | 68.3 (3) | O12—C12—O22 | 124.2 (10) |
O11—Nd1—O31 | 61.7 (2) | O12—C12—C22 | 118.5 (9) |
O1W—Nd1—O31 | 72.3 (3) | O22—C12—C22 | 117.3 (9) |
O32—Nd1—O31 | 112.6 (2) | O32—C22—C12 | 108.2 (8) |
O51—Nd1—O31 | 60.2 (2) | O32—C32—C42 | 108.0 (8) |
O2W—Nd1—O31 | 126.8 (3) | O42—C42—O52 | 123.9 (10) |
O43i—Nd2—O42 | 94.5 (3) | O42—C42—C32 | 118.1 (9) |
O43i—Nd2—O13 | 84.8 (3) | O52—C42—C32 | 117.9 (10) |
O42—Nd2—O13 | 140.6 (3) | C13—O13—Nd2 | 127.1 (7) |
O43i—Nd2—O5W | 80.3 (3) | C33—O33—C23 | 112.8 (8) |
O42—Nd2—O5W | 138.4 (3) | C33—O33—Nd2 | 124.0 (6) |
O13—Nd2—O5W | 80.4 (3) | C23—O33—Nd2 | 123.1 (6) |
O43i—Nd2—O53 | 146.7 (3) | C43—O43—Nd2vii | 144.4 (7) |
O42—Nd2—O53 | 77.8 (3) | C43—O53—Nd2 | 128.3 (7) |
O13—Nd2—O53 | 121.6 (3) | O23—C13—O13 | 125.7 (11) |
O5W—Nd2—O53 | 84.4 (3) | O23—C13—C23 | 115.6 (10) |
O43i—Nd2—O4W | 130.7 (3) | O13—C13—C23 | 118.7 (9) |
O42—Nd2—O4W | 74.9 (3) | O33—C23—C13 | 107.9 (8) |
O13—Nd2—O4W | 76.1 (3) | O33—C33—C43 | 107.7 (9) |
O5W—Nd2—O4W | 137.8 (3) | O53—C43—O43 | 126.1 (10) |
O53—Nd2—O4W | 78.9 (3) | O53—C43—C33 | 117.7 (10) |
O43i—Nd2—O6W | 73.7 (3) | O43—C43—C33 | 116.1 (10) |
O42—Nd2—O6W | 67.4 (2) | C24—O34—C34 | 112.0 (8) |
O13—Nd2—O6W | 146.9 (3) | O14—C14—O24 | 125.7 (11) |
O5W—Nd2—O6W | 71.6 (3) | O14—C14—C24 | 124.9 (10) |
O53—Nd2—O6W | 73.4 (3) | O24—C14—C24 | 109.3 (10) |
O4W—Nd2—O6W | 136.9 (3) | O34—C24—C14 | 107.9 (9) |
O43i—Nd2—O33 | 136.1 (3) | O34—C34—C44 | 106.5 (9) |
O42—Nd2—O33 | 129.4 (3) | O54—C44—O44 | 122.9 (11) |
O13—Nd2—O33 | 61.6 (2) | O54—C44—C34 | 123.5 (10) |
O5W—Nd2—O33 | 67.5 (3) | O44—C44—C34 | 113.5 (10) |
O53—Nd2—O33 | 60.5 (2) |
Symmetry codes: (i) x, y−1, z; (ii) −x+1/2, y+1/2, −z+1/2; (iii) −x+1/2, y−1/2, −z+1/2; (iv) −x, −y+1, −z; (v) −x−1/2, y−1/2, −z+1/2; (vi) x+1/2, −y+3/2, z+1/2; (vii) x, y+1, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | [Pr2(C4H4O5)3(H2O)3]·5H2O | [Nd2(C4H4O5)3(H2O)6]·2H2O·C4H6O5 |
Mr | 822.16 | 962.91 |
Crystal system, space group | Hexagonal, P62c | Monoclinic, P21/n |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 9.4003 (12), 9.4003 (12), 17.350 (4) | 14.096 (2), 6.844 (1), 32.223 (3) |
α, β, γ (°) | 90, 90, 120 | 90, 99.59 (1), 90 |
V (Å3) | 1327.8 (4) | 3065.1 (6) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 3.72 | 3.46 |
Crystal size (mm) | 0.35 × 0.15 × 0.14 | 0.36 × 0.24 × 0.10 |
Data collection | ||
Diffractometer | Siemens R3m diffractometer | Siemens R3m diffractometer |
Absorption correction | ψ-scan (XEMP in SHELXTL/PC; Sheldrick, 1991) | ψ-scan (XEMP in SHELXTL/PC, Sheldrick, 1991) |
Tmin, Tmax | 0.35, 0.60 | 0.38, 0.70 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1693, 780, 738 | 5674, 5393, 3568 |
Rint | 0.034 | 0.040 |
(sin θ/λ)max (Å−1) | 0.595 | 0.595 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.020, 0.059, 1.08 | 0.047, 0.145, 1.03 |
No. of reflections | 780 | 5393 |
No. of parameters | 63 | 419 |
No. of restraints | 0 | 1 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Calculated w = 1/[σ2(Fo2) + (0.031P)2 + 2.733P] where P = (Fo2 + 2Fc2)/3 | Calculated w = 1/[σ2(Fo2) + (0.065P)2 + 37.22P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 0.94, −0.87 | 0.77, −0.89 |
Absolute structure | Flack (1983) | ? |
Absolute structure parameter | −0.02 (4) | ? |
Computer programs: P3/P4-PC (Siemens, 1991), P3/P4-PC, XDISK in SHELXTL/PC (Sheldrick, 1991), XDISK in SHELXTL/PC (Sheldrick,1991), SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997b), XP in SHELXTL/PC (Sheldrick, 1991), CIFTAB (Sheldrick, 1993), PARST (Nardelli, 1983) and CSD (Allen et al., 1983).
Pr1—O2 | 2.444 (4) | Pr2—O3 | 2.552 (5) |
Pr1—O1W | 2.666 (7) | O1—C1 | 1.259 (7) |
Pr2—O1 | 2.478 (4) | O2—C1 | 1.251 (7) |
O1···O2WA | 2.99 (1) | O1W···O2WAi | 2.63 (2) |
O1···O2WB | 2.94 (2) | O1W···O2WBi | 2.96 (3) |
Symmetry code: (i) −y+1, x−y+1, z. |
Nd1—O12 | 2.412 (7) | Nd2—O3W | 2.674 (9) |
Nd1—O41i | 2.445 (8) | O11—C11 | 1.260 (13) |
Nd1—O52 | 2.448 (7) | O21—C11 | 1.246 (13) |
Nd1—O11 | 2.457 (7) | O41—C41 | 1.239 (14) |
Nd1—O1W | 2.462 (9) | O51—C41 | 1.280 (14) |
Nd1—O32 | 2.531 (7) | O12—C12 | 1.253 (12) |
Nd1—O51 | 2.557 (8) | O22—C12 | 1.256 (12) |
Nd1—O2W | 2.566 (8) | O42—C42 | 1.233 (13) |
Nd1—O31 | 2.575 (7) | O52—C42 | 1.276 (13) |
Nd2—O43i | 2.426 (7) | O13—C13 | 1.264 (13) |
Nd2—O42 | 2.455 (7) | O23—C13 | 1.240 (13) |
Nd2—O13 | 2.463 (7) | O43—C43 | 1.262 (13) |
Nd2—O5W | 2.464 (7) | O53—C43 | 1.257 (13) |
Nd2—O53 | 2.485 (8) | O14—C14 | 1.208 (14) |
Nd2—O4W | 2.485 (8) | O24—C14 | 1.322 (13) |
Nd2—O6W | 2.555 (7) | O44—C44 | 1.298 (14) |
Nd2—O33 | 2.568 (7) | O54—C44 | 1.200 (14) |
O1W···O23ii | 2.61 (1) | O4W···O52 | 2.76 (1) |
O1W···O8WA | 2.70 (3) | O5W···O14 | 2.79 (1) |
O2W···O41i | 2.83 (1) | O5W···O34 | 2.90 (1) |
O2W···O23iii | 2.75 (1) | O5W···O54 | 2.72 (1) |
O2W···O8WA | 2.89 (3) | O6W···O43i | 2.99 (1) |
O2W···O8WCiv | 2.81 (2) | O6W···O7W | 2.74 (1) |
O3W···O21iii | 2.73 (1) | O7W···O53v | 2.91 (1) |
O3W···O43i | 2.79 (1) | O8WA···O22iv | 2.74 (2) |
O3W···O52 | 2.90 (1) | O24···O22vi | 2.55 (1) |
O4W···O21ii | 2.61 (1) | O44···O51v | 2.59 (1) |
Symmetry codes: (i) x, y−1, z; (ii) −x+1/2, y+1/2, −z+1/2; (iii) −x+1/2, y−1/2, −z+1/2; (iv) −x, −y+1, −z; (v) −x−1/2, y−1/2, −z+1/2; (vi) x+1/2, −y+3/2, z+1/2. |
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The self-assembly of lanthanide(III) metal centres with oxydiacetate ligands (oda = –O2CCH2OCH2CO2–) leads to a series of crystalline coordination solids formulated as Ln2(oda)3.nH2O with an interesting variety of crystal-packing motifs. This is in accordance with the experience that the crystal structures of the lanthanide compounds frequently change along the series as a result of the lanthanide contraction. The crystals formed by the larger lanthanum [La2(C4H4O5)3(H2O)3. 5H2O]n are hexagonal, P62c (Baggio et al., 1996), and present two nine coordinated La centres; those for the intermediate gadolinium and europium compounds are orthorhombic, Ama2 (Aramendia et al., 1999) and present a mixture of nine and eight coordinated Ln centres, as it is also the case for the smaller Er (Elding, 1977) and Y (Baggio et al., 1999) analogues, which crystallize in the orthorhombic space group C222 (1).
Focusing our attention primarily on the structural aspects of these extended polymeric 4f complexes we report herein the preparation and structural characterization of the analogous compounds comprising praseodymium and neodymium: [Pr2(C4H4O5)3(H2O)3·5H2O]n, (I), and [Nd2(C4H4O5)3(H2O)6·2H2O·C4H6O5]n, (II). \sch
Compound (I) is isostructural to the lanthanum polymer (Baggio, 1996) and will not be described in too much detail here. Selected bond lengths and angles are listed in Table 1, and Figure 1 gives a sketch of its coordination scheme. The two metal centres are highly symmetric, with Pr2 occupying a site `a' of local symmetry 32, and coordinated to three tridentate oda units, while Pr1, which occupies a site `d' of symmetry \-6, receives six bonds from the outer carboxylate O atoms as well as those from three aqua molecules. Both coordination polyhedra have the shape of tricapped trigonal prisms, the one around Pr2 being regular and the one centred at Pr1 displaying a rotation of ca 13° between opposite triangular faces. The fact that all the carboxylate as well as the ether O atoms take part in the connectivity to the cations leads to a tightly woven three dimensional network, leaving only a few empty spaces, filled in turn by the (disordered) hydration water molecules, which attach to the main structure via hydrogen bonding (See Table 2 for short O···O contacts).
Compound (2) presents, instead, a novel disposition of the ligands, not found before in any member of the series. As already stated, two independent Nd centres are present: Nd1 is bonded to two tridentate oda groups (oda1 and oda2) and to two water molecules (O1W and O2W). The ninth bond (O41) is provided by a <010> translationally related oda1 ligand, to end up with a linear polymeric chain along the short unique b axis.
As it is often the case with lanthanide cations bound to three tridentate oda groups, or to two tridentate odas plus three extra monodentate units completing the ninefold environment (the present case), the Nd1 polyhedron displays a tricapped trigonal prismatic geometry. The three monodentate ligands (O1W, O2W and O41) adopt a planar configuration very much resembling that of the missing third oda unit. The resulting polyhedron is one with only slight modifications from the regular environment found in much more symmetric polyhedra [e.g. the one around Pr1 in (I)].
A completely different arrangement is found for Nd2, which is bonded to a single tridentate oxydiacetate group (oda3) and to six monodentate units, four of which are water molecules (O3W to O6W), and the remaining two, oxygen atoms from bridging carboxylates. One of these is O43 from a neigbouring (also a <010> translationally related) oxydiacetate unit, again to built up linear chains parallel to those already defined by the Nd1 polyhedra. The second, O42, is provided by these latter groups; the Nd—O42 bonds transversally link both types of linear arrays, acting as the rungs of a firmly connected ladder-like strip (Fig. 2).
The presence of a single tridentate, plus six monodentate ligands favours a less constrained environment around Nd2 in the form of a monocapped square antiprism in which O33 occupies the capping position; O13, O53, O4W and O5W the equatorial plane and the remaining two water molecules plus the two remaining bridging carboxylate O atoms (O42 and O43) the basal plane. The largest distortion in the polyhedron is observed at the rather long Nd2—O3W distance [2.674 (9) Å]. The structure is completed by two non-coordinated water molecules (O7 and a triply disordered O8W) and an H2oda neutral molecule. All of them, as well as the six coordinated water molecules, play an active role as hydrogen donors in a dense hydrogen bonding network in which the oxygen atoms from the coordinated oda groups act mainly as acceptors. Although the H atoms bonded to O atoms could not be reliably located, the hydrogen bonding interaction scheme could be confidently guessed both from the shortest (< 3.0 Å) O···O contacts (shown in Table 4) as well as from some significant structural details (viz C14—O24 and C44—O44 are sensibly longer than C14—O14 and C44—O54, respectively, at the same time that O24···O22 and O44···O51 are rather short. Charge balance and IR data (see Experimental section) required the presence of two OH groups in oda4; the preceeding geometrical arguments, in turn, point almost unambigously to the protonated character of O24 and O44.