Poly­[tri­aqua(μ-hydrogen tartrato)(μ-tartrato)­samarium(III)]

The nine-coordinate Sm^III cation in [Sm{O₂CCH(OH)CH(OH)CO₂}{O₂CCH(OH)CH(OH)CO₂H}(OH₂)₃], or [Sm(C₄H₄O₆)(C₄H₅O₆)(H₂O)₃]_n, is located on a crystallographic twofold axis. The coordination geometry is capped square-antiprismatic and is defined by four O atoms derived from carboxyl­ate/carboxyl­ic acid groups, two hydroxyl O atoms and three water mol­ecules. The Sm^III atoms are linked by the tartrate ligands into layers, which are connected via O—H...O hydrogen bonds involving the carboxyl­ate and hydroxyl O atoms, and water mol­ecules.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.011 Å
• H-atom completeness 94%
• R factor = 0.028
• wR factor = 0.072
• Data-to-parameter ratio = 10.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



FORMU_01  There is a discrepancy between the atom counts in the
          _chemical_formula_sum and the formula from the _atom_site* data.
          Atom count from _chemical_formula_sum:C8 H15 O15 Sm1
          Atom count from the _atom_site data:  C8 H14 O15 Sm1

CELLZ_01
         From the CIF: _cell_formula_units_Z    4
         From the CIF: _chemical_formula_sum  C8 H15 O15 Sm
         TEST: Compare cell contents of formula and atom_site data

         atom    Z*formula  cif sites diff
         C         32.00     32.00    0.00
         H         60.00     56.00    4.00
         O         60.00     60.00    0.00
         Sm         4.00      4.00    0.00
          Difference between formula and atom_site contents detected.
          WARNING: H atoms missing from atom site list. Is this intentional?

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           25.00
         From the CIF: _reflns_number_total               1205
         Count of symmetry unique reflns          810
         Completeness (_total/calc)            148.77%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       395
         Fraction of Friedel pairs measured     0.488
         Are heavy atom types Z>Si present          yes
          WARNING: Large fraction of Friedel related reflns may
                   be needed to determine absolute structure

---

S1. Comment

Owing to their enormous variety of intriguing structural topologies, chemists have devoted great effort to the research of novel chiral coordination materials. Recently, the crystal engineering strategy has been utilized in the construction of metal–organic coordination polymers by using asymmetric bridging ligands as building blocks (Rowan & Nolte, 1998; Amabilino & Stoddart, 1995; Piguet et al., 1997; Biradha et al., 1999). The higher coordination numbers of lanthanide ions and the inherent flexibility of their coordination geometries might lead to some unprecedented topological architectures (Long et al., 2000, 2001; Pan et al., 2000). We are currently interested in pursuing synthetic strategies by using lanthanide ions as nodes in the construction of chiral polymeric frameworks. Tartaric acid, which has six O atoms as potential donors, is a rather versatile ligand for the synthesis of chiral polymeric complexes containing lanthanide cations. To date, only two tartrate-bridged lanthanide complexes have been reported (Hawthorne et al., 1983; Starynowicz & Meyer, 2000). As part of our investigations of polycarboxylic acid-bridged chiral polymeric complexes, the title complex [Sm(C₄H₄O₆)(C₄H₅O₆)(H₂O)₃]_n, (I), was prepared and obtained as colorless crystals.

The title compound comprises two-dimensional chiral sheets that are built up by connecting the Sm^III cations with its neighbors through bridging tartrate ligands. The crystal structure and the coordination modes of tartrate ligands are similar to the previously reported Er^IV complex [Er{O₂CCH(OH)CH(OH)CO₂}₂(OH₂)₃] (Hawthorne et al., 1983). The molecular structure has twofold symmetry so that the asymmetric unit comprises half an Sm cation, one tartrate anion and 1.5 water molecules. Atoms Sm and O8, of a coordinated water molecule, lie on the symmetry axis. This implies some disorder in the structure in that the non-coordinating carboxylate residue (containing the O5 and O6 atoms) is protonated 50% of the time. For the tartrate ligand, the hydroxyl O3 atom and atom O2 of the coordinating carboxylate group chelates a Sm atom. Atom O1 bridges a symmetry-related Sm atom. Four carboxylate O atoms, two hydroxyl O atoms and three water molecules form a distorted monocapped square-antiprismatic coordination sphere (Fig. 1). The mean Sm—O_carboxylate distance of 2.378 (5) Å is about 0.173 Å shorter than the average length of the Sm—O_hydroxyl bond. The Sm—O_water bond lengths are in the range 2.463 (6)–2.732 (15) Å, with the longer bond involving the water molecule lying on the symmetry axis. Each tartrate ligand acts as a bridging ligand connecting two Sm atoms into a two-dimensional chiral structure (Fig. 2). The layers are linked together through a complicated hydrogen-bonding scheme involving the water ligands, hydroxyl O atoms and the carboxylate O atoms. Thus, a three-dimensional framework is produced (Fig. 3), in which the mean O—H···O hydrogen-bonding distance is 2.745 (9) Å.

S2. Experimental

The pH of a mixture of SmCl₃ (5.0 mmol) (prepared from Sm₂O₃ dissolved in 35% HCl) and L-tartaric acid (1.50 g, 10.0 mmol) in H₂O (60 ml) was adjusted to 1.66 with 10% HCl under vigorous stirring. Colorless crystals of the title compound were isolated after three weeks.

S3. Refinement

H atoms were included as riding. Disorder is evident in the structure in that the crystallographically independent tartrate anion is protonated at the O5 and O6 carboxyl O atoms 50% of the time.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1994); data reduction: SMART and SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1994); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A perspective view of the locally expanded unit for (I). Displacement ellipsoids are drawn at the 30% probability level [symmetry codes: (i) y, x, 1 - z; (ii) x, -1 + y, z; (iii) -1 + y, x, 1 - z].
	Fig. 2. A view down the c axis, showing the extended lamellar structure of (I). For clarity, H atoms had been omitted.
	Fig. 3. Cell-packing diagram viewed down the b axis. Hydrogen bonding is indicated by dashed lines.

Poly[triaqua(µ-hydrogen tartrato)(µ-tartrato)samarium(III)]

Crystal data

[Sm(C4H4O6)(C4H5O6)(H2O)3]	Dx = 2.429 Mg m^−3
Mr = 501.55	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P41212	Cell parameters from 207 reflections
a = 6.1030 (3) Å	θ = 2.2–25.0°
c = 36.826 (2) Å	µ = 4.37 mm^−1
V = 1371.6 (1) Å^3	T = 293 K
Z = 4	Rhombus, colorless
F(000) = 980	0.42 × 0.40 × 0.30 mm

Data collection

Siemens SMART CCD diffractometer	1205 independent reflections
Radiation source: fine-focus sealed tube	1185 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.025
ϕ and ω scans	θmax = 25.0°, θmin = 2.2°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −6→3
Tmin = 0.172, Tmax = 0.269	k = −7→6
3367 measured reflections	l = −27→43

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.028	w = 1/[σ^2(Fo^2) + (0.0139P)^2 + 15.128P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.072	(Δ/σ)max < 0.001
S = 1.00	Δρmax = 0.77 e Å^−3
1205 reflections	Δρmin = −1.01 e Å^−3
111 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0024 (3)
Primary atom site location: structure-invariant direct methods	Absolute structure: (Flack, 1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.00 (4)

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
Sm	0.67900 (6)	0.67900 (6)	0.5000	0.02227 (18)
O1	0.7814 (10)	1.3751 (8)	0.46290 (16)	0.0356 (14)
O2	0.7024 (10)	1.0631 (8)	0.49160 (11)	0.0307 (12)
O3	0.8359 (9)	0.8150 (9)	0.43987 (11)	0.0262 (9)
H3B	0.8070	0.7396	0.4221	0.039*
O4	1.2103 (10)	1.1054 (9)	0.43712 (18)	0.0424 (16)
H4A	1.3164	1.1736	0.4294	0.059*
O5	0.9239 (12)	1.0527 (12)	0.35287 (17)	0.0530 (17)
O6	1.2365 (10)	0.8974 (10)	0.37169 (16)	0.0439 (16)
O7	0.3777 (9)	0.6976 (12)	0.45559 (15)	0.0497 (17)
H7A	0.2951	0.5933	0.4586	0.060*
H7B	0.3725	0.8084	0.4395	0.060*
O8	0.3625 (17)	0.3625 (17)	0.5000	0.110 (5)
H8A	0.2418	0.4198	0.5023	0.165*
C1	0.7672 (11)	1.1692 (12)	0.46480 (19)	0.0256 (16)
C2	0.8230 (14)	1.0406 (11)	0.4303 (2)	0.0255 (15)
H2A	0.7026	1.0591	0.4130	0.031*
C3	1.0342 (13)	1.1277 (12)	0.4127 (2)	0.034 (2)
H3A	1.0138	1.2843	0.4079	0.041*
C4	1.0745 (14)	1.0133 (13)	0.3764 (3)	0.038 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sm	0.0238 (2)	0.0238 (2)	0.0191 (2)	0.0050 (2)	0.00144 (18)	−0.00144 (18)
O1	0.038 (3)	0.021 (3)	0.048 (3)	−0.001 (2)	0.022 (3)	−0.002 (2)
O2	0.056 (3)	0.025 (3)	0.011 (2)	0.003 (2)	0.008 (2)	0.0032 (19)
O3	0.032 (3)	0.020 (2)	0.027 (2)	−0.002 (2)	0.003 (2)	−0.004 (2)
O4	0.028 (3)	0.040 (3)	0.059 (4)	−0.010 (3)	0.006 (3)	−0.016 (3)
O5	0.060 (5)	0.048 (4)	0.051 (4)	0.021 (3)	0.001 (4)	−0.001 (3)
O6	0.051 (4)	0.043 (3)	0.038 (3)	0.016 (3)	0.011 (3)	−0.004 (3)
O7	0.033 (3)	0.077 (5)	0.039 (3)	−0.017 (3)	0.007 (2)	−0.010 (3)
O8	0.094 (7)	0.094 (7)	0.142 (12)	0.021 (8)	0.010 (8)	−0.010 (8)
C1	0.022 (3)	0.023 (4)	0.032 (4)	0.005 (3)	−0.005 (3)	−0.009 (3)
C2	0.025 (4)	0.020 (3)	0.031 (4)	0.003 (3)	−0.002 (4)	0.000 (3)
C3	0.036 (4)	0.021 (4)	0.044 (5)	−0.002 (3)	0.015 (4)	−0.002 (3)
C4	0.046 (5)	0.029 (4)	0.039 (4)	0.003 (4)	0.016 (4)	0.002 (3)

Geometric parameters (Å, º)

Sm—O2^i	2.369 (5)	O3—H3B	0.8200
Sm—O2	2.369 (5)	O4—C3	1.407 (10)
Sm—O1^ii	2.387 (5)	O4—H4A	0.8200
Sm—O1^iii	2.387 (5)	O5—C4	1.285 (11)
Sm—O7^i	2.463 (6)	O6—C4	1.228 (9)
Sm—O7	2.463 (6)	O7—H7A	0.8200
Sm—O3^i	2.551 (4)	O7—H7B	0.8999
Sm—O3	2.551 (4)	O8—H8A	0.8200
Sm—O8	2.732 (15)	C1—C2	1.531 (10)
O1—C1	1.261 (9)	C2—C3	1.537 (10)
O1—Sm^iv	2.387 (5)	C2—H2A	0.9800
O2—C1	1.245 (8)	C3—C4	1.529 (12)
O3—C2	1.423 (9)	C3—H3A	0.9800
O2^i—Sm—O2	84.1 (3)	O7^i—Sm—O8	60.3 (2)
O2^i—Sm—O1^ii	132.7 (2)	O7—Sm—O8	60.3 (2)
O2—Sm—O1^ii	82.1 (2)	O3^i—Sm—O8	119.7 (1)
O2^i—Sm—O1^iii	82.1 (2)	O3—Sm—O8	119.7 (1)
O2—Sm—O1^iii	132.7 (2)	C1—O1—Sm^iv	136.4 (5)
O1^ii—Sm—O1^iii	137.3 (3)	C1—O2—Sm	129.6 (5)
O2^i—Sm—O7^i	85.0 (2)	C2—O3—Sm	120.6 (4)
O2—Sm—O7^i	145.3 (2)	C2—O3—H3B	109.5
O1^ii—Sm—O7^i	81.4 (2)	Sm—O3—H3B	115.5
O1^iii—Sm—O7^i	77.8 (2)	C3—O4—H4A	109.5
O2^i—Sm—O7	145.3 (2)	Sm—O7—H7A	109.5
O2—Sm—O7	85.0 (2)	Sm—O7—H7B	119.9
O1^ii—Sm—O7	77.8 (2)	H7A—O7—H7B	130.6
O1^iii—Sm—O7	81.4 (2)	Sm—O8—H8A	109.5
O7^i—Sm—O7	120.6 (3)	O2—C1—O1	125.7 (7)
O2^i—Sm—O3^i	62.7 (2)	O2—C1—C2	117.5 (6)
O2—Sm—O3^i	73.9 (2)	O1—C1—C2	116.7 (6)
O1^ii—Sm—O3^i	70.0 (2)	O3—C2—C1	107.7 (6)
O1^iii—Sm—O3^i	134.7 (2)	O3—C2—C3	113.1 (6)
O7^i—Sm—O3^i	71.9 (2)	C1—C2—C3	111.0 (6)
O7—Sm—O3^i	143.3 (2)	O3—C2—H2A	108.3
O2^i—Sm—O3	73.9 (2)	C1—C2—H2A	108.3
O2—Sm—O3	62.7 (2)	C3—C2—H2A	108.3
O1^ii—Sm—O3	134.7 (2)	O4—C3—C4	113.0 (6)
O1^iii—Sm—O3	70.0 (2)	O4—C3—C2	109.7 (6)
O7^i—Sm—O3	143.3 (2)	C4—C3—C2	110.2 (6)
O7—Sm—O3	71.9 (2)	O4—C3—H3A	107.9
O3^i—Sm—O3	120.6 (2)	C4—C3—H3A	107.9
O2^i—Sm—O8	137.9 (2)	C2—C3—H3A	107.9
O2—Sm—O8	137.9 (2)	O6—C4—O5	126.1 (8)
O1^ii—Sm—O8	68.6 (1)	O6—C4—C3	121.1 (8)
O1^iii—Sm—O8	68.6 (1)	O5—C4—C3	112.9 (7)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3B···O6^v	0.82	1.87	2.681 (7)	173
O4—H4A···O5^vi	0.82	2.15	2.867 (9)	146
O7—H7A···O8	0.82	2.12	2.621 (11)	120
O7—H7B···O4^vii	0.90	2.07	2.775 (10)	135
O8—H8A···O2^ii	0.82	2.05	2.782 (6)	148

Symmetry codes: (ii) y−1, x, −z+1; (v) x−1/2, −y+3/2, −z+3/4; (vi) x+1/2, −y+5/2, −z+3/4; (vii) x−1, y, z.