Poly[bis­(μ₃-dihydrogen malonato)calcium(II)]

The title compound, [Ca(C₃H₃O₄)₂]_n, has a polymeric structure, built up from noncentrosymmetric Ca₂O₁₂ face-sharing bipolyhedra, linked through the spacers of the ligands and forming a complex three-dimensional framework containing empty channels parallel to the [001] direction. The calcium ion lies on a 2 axis and is coordinated by eight O atoms from six hydrogen malonate ligands in a distorted bicapped dodeca­hedron. The tridentate ligand displays an η⁵-chelating coordination mode and forms both μ_1,1 and μ_1,3 bridges. In the extended network, the protonated O atom is involved in a strong hydrogen bond with a deprotonated O atom, forming an infinite array of the ligands. An M—O—M infinite linkage characteristic of metal–organic frameworks is prevented here by cage assembly around the metal.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.028
• wR factor = 0.070
• Data-to-parameter ratio = 16.9

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT111_ALERT_2_B ADDSYM Detects (Pseudo) Centre of Symmetry .....         87 PerFi

Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.03
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.33 Ratio

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           29.98
           From the CIF: _reflns_number_total               1215
           Count of symmetry unique reflns          712
           Completeness (_total/calc)            170.65%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       503
           Fraction of Friedel pairs measured     0.706
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO-MSN (Otwinowski & Minor, 1997); data reduction: DENZO-MSN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Poly[bis(µ₃-dihydrogen malonato)calcium(II)]

Crystal data

[Ca(C3H3O4)2]	Dx = 1.965 Mg m^−3
Mr = 246.19	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P421c	Cell parameters from 17857 reflections
Hall symbol: P-42n	θ = 3.0–32.7°
a = 7.8705 (1) Å	µ = 0.78 mm^−1
c = 13.4367 (7) Å	T = 100 K
V = 832.33 (5) Å^3	Prism, colourless
Z = 4	0.3 × 0.2 × 0.2 mm
F(000) = 504

Data collection

Nonius KappaCCD diffractometer	1215 independent reflections
Radiation source: fine-focus sealed tube	1183 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ω scans	θmax = 30.0°, θmin = 3.0°
Absorption correction: part of the refinement model (ΔF) (DIFABS; Walker & Stuart, 1983)	h = −10→11
Tmin = 0.804, Tmax = 0.830	k = −11→11
16443 measured reflections	l = −18→18

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.028	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.070	w = 1/[σ^2(Fo^2) + (0.0477P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max < 0.001
1215 reflections	Δρmax = 0.39 e Å^−3
72 parameters	Δρmin = −0.25 e Å^−3
1 restraint	Absolute structure: Flack (1983), 504 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.02 (6)

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
Ca	0.5000	0.5000	0.13496 (3)	0.01000 (11)
O1	0.69334 (15)	0.63476 (16)	0.02648 (8)	0.0139 (2)
O2	0.94509 (15)	0.69424 (17)	−0.03949 (8)	0.0158 (3)
C1	0.84141 (19)	0.68269 (19)	0.03595 (10)	0.0112 (3)
C2	0.9185 (2)	0.7426 (2)	0.13265 (11)	0.0133 (3)
H21	0.9017	0.8671	0.1372	0.016*
H22	1.0425	0.7221	0.1295	0.016*
C3	0.8517 (2)	0.6630 (2)	0.22875 (11)	0.0115 (3)
O3	0.74402 (17)	0.54852 (15)	0.22770 (8)	0.0160 (3)
O4	0.91839 (15)	0.72053 (15)	0.30858 (8)	0.0138 (3)
H2	0.895 (3)	0.651 (3)	−0.0995 (12)	0.021*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.01005 (19)	0.0113 (2)	0.00867 (18)	−0.0009 (2)	0.000	0.000
O1	0.0133 (5)	0.0175 (6)	0.0110 (5)	−0.0032 (4)	0.0005 (4)	0.0003 (4)
O2	0.0154 (5)	0.0241 (6)	0.0080 (5)	−0.0042 (5)	0.0012 (4)	−0.0012 (5)
C1	0.0137 (7)	0.0112 (6)	0.0087 (6)	−0.0003 (6)	0.0010 (5)	0.0010 (5)
C2	0.0163 (7)	0.0155 (7)	0.0081 (6)	−0.0044 (6)	−0.0003 (6)	−0.0005 (6)
C3	0.0118 (7)	0.0113 (7)	0.0113 (6)	0.0023 (5)	0.0000 (5)	0.0002 (5)
O3	0.0161 (6)	0.0200 (6)	0.0118 (5)	−0.0047 (4)	−0.0038 (5)	0.0025 (4)
O4	0.0188 (6)	0.0141 (6)	0.0086 (5)	−0.0018 (5)	−0.0010 (4)	−0.0005 (4)

Geometric parameters (Å, º)

Ca—O3	2.3210 (12)	O1—Ca^v	2.8541 (12)
Ca—O3^i	2.3210 (12)	O2—H2	0.962 (14)
Ca—O1^i	2.3591 (12)	C1—C2	1.509 (2)
Ca—O1	2.3591 (12)	C2—C3	1.528 (3)
Ca—O4^ii	2.4137 (12)	C2—H21	0.990
Ca—O4^iii	2.4137 (12)	C2—H22	0.990
Ca—O1^iv	2.8541 (12)	C3—O3	1.236 (3)
Ca—O1^v	2.8541 (12)	C3—O4	1.278 (2)
Ca—Ca^v	3.6268 (8)	O4—Ca^vi	2.4134 (15)
O1—C1	1.231 (2)
O3—Ca—O3^i	115.06 (6)	O1—Ca—O1^iv	61.99 (2)
O3—Ca—O1^i	159.96 (4)	O4^ii—Ca—O1^iv	145.45 (4)
O3^i—Ca—O1^i	73.98 (4)	O4^iii—Ca—O1^iv	69.76 (4)
O3—Ca—O1	73.98 (4)	O3—Ca—O1^v	128.89 (4)
O3^i—Ca—O1	159.96 (4)	O3^i—Ca—O1^v	100.85 (4)
O1^i—Ca—O1	103.68 (6)	O1^i—Ca—O1^v	61.99 (2)
O3—Ca—O4^ii	84.35 (4)	O1—Ca—O1^v	61.99 (2)
O3^i—Ca—O4^ii	76.17 (4)	O4^ii—Ca—O1^v	69.76 (4)
O1^i—Ca—O4^ii	115.61 (4)	O4^iii—Ca—O1^v	145.45 (4)
O1—Ca—O4^ii	87.49 (4)	O1^iv—Ca—O1^v	81.07 (5)
O3—Ca—O4^iii	76.17 (4)	C1—O2—H2	112.6 (16)
O3^i—Ca—O4^iii	84.35 (4)	O1—C1—O2	122.13 (18)
O1^i—Ca—O4^iii	87.49 (4)	O1—C1—C2	124.43 (17)
O1—Ca—O4^iii	115.61 (4)	O2—C1—C2	113.36 (17)
O4^ii—Ca—O4^iii	143.36 (6)	C1—C2—C3	117.45 (17)
O3—Ca—O1^iv	100.85 (4)	O3—C3—O4	123.32 (18)
O3^i—Ca—O1^iv	128.89 (4)	O3—C3—C2	121.68 (17)
O1^i—Ca—O1^iv	61.99 (2)	O4—C3—C2	114.98 (18)
O4^iii—Ca—O1—Ca^v	93.82 (4)	C2—C3—O3—Ca	−40.7 (2)
O1^iv—Ca—O1—Ca^v	47.40 (3)	O3^i—Ca—O3—C3	−126.36 (16)
O1^v—Ca—O1—Ca^v	−47.40 (3)	O1^i—Ca—O3—C3	120.52 (16)
Ca—O1—C1—O2	153.10 (11)	O1—Ca—O3—C3	34.50 (15)
Ca^v—O1—C1—O2	6.7 (2)	O4^ii—Ca—O3—C3	−54.50 (15)
Ca—O1—C1—C2	−30.5 (2)	O4^iii—Ca—O3—C3	156.76 (16)
Ca^v—O1—C1—C2	−176.83 (10)	O1^iv—Ca—O3—C3	90.96 (15)
O1—C1—C2—C3	31.6 (2)	O1^v—Ca—O3—C3	3.74 (17)
O2—C1—C2—C3	−151.72 (14)	Ca^v—Ca—O3—C3	53.64 (16)
C1—C2—C3—O3	3.1 (2)	O3—C3—O4—Ca^vi	−141.14 (13)
C1—C2—C3—O4	−178.56 (14)	C2—C3—O4—Ca^vi	40.5 (2)
O4—C3—O3—Ca	141.05 (13)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O4^vii	0.96 (2)	1.63 (2)	2.5800 (17)	168 (1)
O2—H2···O3^vii	0.96 (2)	2.50 (2)	3.1660 (18)	126 (1)

Symmetry code: (vii) −y+3/2, −x+3/2, z−1/2.