catena-Poly[[diaqua­calcium]bis­[μ-2-(1,3-dioxoisoindolin-2-yl)acetato]-κ3O,O′:O;κ3O:O,O′]

Bhatti, M.H.; Yunus, U.; Saeed, S.; Shah, S.R.; Wong, W.-T.

doi:10.1107/S1600536811027851

metal-organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Pages m1102-m1103

doi:10.1107/S1600536811027851

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catena-Poly[[diaquacalcium]bis[μ-2-(1,3-dioxoisoindolin-2-yl)acetato]-κ³O,O′:O;κ³O:O,O′]

Moazzam H. Bhatti,^a Uzma Yunus,^a Sohail Saeed,^a ^* Syed Raza Shah ^a and Wing-Tak Wong ^b

^aDepartment of Chemistry, Research Complex, Allama Iqbal Open University, Islamabad 44000, Pakistan, and ^bDepartment of Chemistry, The University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong SAR, People's Republic of China
^*Correspondence e-mail: sohail262001@yahoo.com

(Received 23 June 2011; accepted 11 July 2011; online 16 July 2011)

In the title complex, [Ca(C₁₀H₆NO₄)₂(H₂O)₂]_n, the Ca^II atom lies on a twofold rotation axis and adopts a dodecahedral geometry. The Ca^II atom is octacoordinated by two O atoms from two water molecules and six O atoms from four acetate ligands. Each acetate acts as a tridentate ligand bridging two Ca^II atoms, resulting in a chain running along the c axis. O—H⋯O and C—H⋯O hydrogen bonds connect the chains into a two-dimensional network parallel to [011]. π–π interactions between adjacent isoindoline-1,3-dione rings [centroid–centroid distance = 3.4096 (11) Å] further consolidate the structure. One of the carboxylate O atoms is disordered over two sites in a 0.879 (12):0.121 (12) ratio.

Related literature

For background to N-phthaloylglycine, see: Khan & Ismail (2002 ). For related structures, see: Barooah et al. (2006 ).

Experimental

Crystal data

[Ca(C₁₀H₆NO₄)₂(H₂O)₂]
M_r = 484.43
Monoclinic, C 2/c
a = 32.752 (1) Å
b = 9.0435 (3) Å
c = 6.9753 (3) Å
β = 99.020 (2)°
V = 2040.48 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 296 K
0.34 × 0.32 × 0.32 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a ) T_min = 0.884, T_max = 0.890
12481 measured reflections
2339 independent reflections
1847 reflections with I > 2σ(I)
R_int = 0.042

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.102
S = 1.04
2339 reflections
160 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5A⋯O4ⁱ	0.82 (1)	2.10 (1)	2.907 (2)	171 (3)
O5—H5B⋯O4ⁱⁱ	0.82 (1)	2.49 (2)	3.095 (2)	131 (2)
C8—H8⋯O2ⁱⁱⁱ	0.93	2.47	3.318 (2)	151
Symmetry codes: (i) $[x, -y+1, z+{\script{1\over 2}}]$ ; (ii) x, y, z+1; (iii) $[x, -y+1, z-{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: Mercury (Macrae et al., 2008 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811027851/pv2422sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811027851/pv2422Isup2.hkl

checkCIF report

Comment top

N-Phthaloylglycine is a simple N-phthaloylamino acid which has been widely studied for cleavage with various amines (Khan & Ismail, 2002) and metal complexation with interesting supramolecular structures (Barooah et al., 2006). In an attempt to synthesis calcium(II) complex of N-phthaloylglycine, we have prepared a calcium complex of N-phthaloylglycine as the title compound and studied it crystal structure which is presented in this article.

In the title complex, the calcium ayom is octa-coordinated to two oxygen atoms from two water solvates and to 6 oxygen atoms from four acetate ligands. Each acetate acts as a tridentate ligand bridging two calcium centres resulting in a 1-D polymeric chain running along the c-axis. The calcium atom sits on a 2-fold axis, thus the asymmetric unit contains only half of the complex (Fig. 1).

The oxygen atom O1 is slightly disordered over two sites with occupancy factors 0.879 (12) and 0.121 (12). The acetate ring plane, C1/C2/O1/O2, makes a dihedral angle of 75.62 (8)° (77.0 (4)° for C1/C2/O1B/O2) with the ring plane of the isoindole-1,3-dione, N1/O3/O4/C3—C10.

There are inter-molecular O—H···O H-bonding interactions which link the molecules into a 2-D network parallel to the [0 1 1] plane (Fig. 2). There are also weak π–π interactions between adjacent isoindole-1,3-dione rings along the c axis in the crystal lattice; the distance between the centroids of the rings C4—C9 and (N1/C3/C4/C9/C10)^* (^*: x, 1 - y, 1/2 + z) being 3.4096 (11) Å. These π–π interactions help stacking the acetate ligand plane along the c-axis in the lattice.

Related literature top

For background to N-phthaloylglycine, see: Khan & Ismail (2002). For related structures, see: Barooah et al. (2006).

Experimental top

The title compound was prepared from the reaction of CaCl₂.2H₂O (0.01 mol) and sodium (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)acetate (0.02 mol) solution. Sodium (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)acetate was first obtained by adding 0.02 mol of (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)acetic acid to an aqueous solution of 0.02 mol NaHCO₃. The mixture was set aside to crystallize at ambient temperature for several days, giving suitable colorless single crystals.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008b).

Figures top

	Fig. 1. The asymmetric unit of the title complex drwan with 50% probability thermal ellipsoids showing the atom numbering scheme.
	Fig. 2. The packing diagram of the complex projected down the b axis showing the 1-D chain running parallel to the c axis; the cyan dotted lines indicate the H-bonding interactions.

catena-Poly[[diaquacalcium]bis[µ-2-(1,3-dioxoisoindolin-2- yl)acetato]-κ³O,O':O;κ³O:O,O'] top

Crystal data top

[Ca(C₁₀H₆NO₄)₂(H₂O)₂]	F(000) = 1000
M_r = 484.43	D_x = 1.577 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 12481 reflections
a = 32.752 (1) Å	θ = 2.3–27.5°
b = 9.0435 (3) Å	µ = 0.37 mm⁻¹
c = 6.9753 (3) Å	T = 296 K
β = 99.020 (2)°	Block, colourless
V = 2040.48 (13) Å³	0.34 × 0.32 × 0.32 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	2339 independent reflections
Radiation source: fine-focus sealed tube	1847 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.042
ω and ϕ scans	θ_max = 27.5°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	h = −42→42
T_min = 0.884, T_max = 0.890	k = −11→11
12481 measured reflections	l = −8→9

Refinement top

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0543P)² + 0.9315P] where P = (F_o² + 2F_c²)/3
2339 reflections	(Δ/σ)_max = 0.001
160 parameters	Δρ_max = 0.28 e Å⁻³
3 restraints	Δρ_min = −0.23 e Å⁻³

Crystal data top

[Ca(C₁₀H₆NO₄)₂(H₂O)₂]	V = 2040.48 (13) Å³
M_r = 484.43	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 32.752 (1) Å	µ = 0.37 mm⁻¹
b = 9.0435 (3) Å	T = 296 K
c = 6.9753 (3) Å	0.34 × 0.32 × 0.32 mm
β = 99.020 (2)°

Data collection top

Bruker APEXII CCD diffractometer	2339 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	1847 reflections with I > 2σ(I)
T_min = 0.884, T_max = 0.890	R_int = 0.042
12481 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	3 restraints
wR(F²) = 0.102	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.28 e Å⁻³
2339 reflections	Δρ_min = −0.23 e Å⁻³
160 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ca1	0.0000	0.12307 (5)	0.2500	0.02944 (16)
O1	0.03670 (7)	0.0467 (4)	−0.0362 (7)	0.0520 (9)	0.879 (12)
O1B	0.0322 (5)	0.084 (2)	−0.126 (5)	0.0520 (9)	0.121 (12)
O2	0.07083 (4)	0.19128 (16)	0.1763 (2)	0.0468 (4)
O3	0.18731 (4)	0.15606 (15)	0.0563 (2)	0.0509 (4)
O4	0.07509 (4)	0.44337 (16)	−0.1576 (2)	0.0471 (4)
O5	0.02298 (6)	0.3258 (2)	0.4645 (3)	0.0691 (5)
H5A	0.0399 (7)	0.384 (3)	0.433 (4)	0.104*
H5B	0.0228 (10)	0.337 (4)	0.5810 (11)	0.104*
N1	0.12562 (4)	0.27067 (16)	−0.0647 (2)	0.0338 (3)
C1	0.06666 (5)	0.12894 (18)	0.0183 (3)	0.0341 (4)
C2	0.09973 (6)	0.1420 (2)	−0.1122 (3)	0.0387 (4)
H2A	0.1168	0.0539	−0.0985	0.046*
H2B	0.0865	0.1484	−0.2465	0.046*
C3	0.16724 (5)	0.2673 (2)	0.0189 (3)	0.0343 (4)
C4	0.17993 (5)	0.4252 (2)	0.0462 (3)	0.0320 (4)
C5	0.21772 (6)	0.4866 (2)	0.1170 (3)	0.0391 (4)
H5	0.2407	0.4280	0.1583	0.047*
C6	0.22000 (6)	0.6402 (2)	0.1243 (3)	0.0438 (5)
H6	0.2450	0.6852	0.1737	0.053*
C7	0.18598 (6)	0.7274 (2)	0.0598 (3)	0.0436 (5)
H7	0.1886	0.8298	0.0661	0.052*
C8	0.14793 (6)	0.6653 (2)	−0.0144 (3)	0.0380 (4)
H8	0.1251	0.7237	−0.0596	0.046*
C9	0.14567 (5)	0.5126 (2)	−0.0178 (2)	0.0311 (4)
C10	0.11039 (5)	0.41339 (19)	−0.0884 (3)	0.0331 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ca1	0.0250 (2)	0.0241 (2)	0.0391 (3)	0.000	0.00463 (19)	0.000
O1	0.0402 (9)	0.0575 (14)	0.062 (2)	−0.0247 (9)	0.0201 (11)	−0.0249 (15)
O1B	0.0402 (9)	0.0575 (14)	0.062 (2)	−0.0247 (9)	0.0201 (11)	−0.0249 (15)
O2	0.0444 (8)	0.0546 (9)	0.0438 (8)	−0.0091 (7)	0.0146 (6)	−0.0066 (7)
O3	0.0449 (8)	0.0355 (7)	0.0711 (11)	0.0061 (6)	0.0050 (7)	0.0046 (7)
O4	0.0340 (7)	0.0455 (8)	0.0583 (10)	−0.0011 (6)	−0.0033 (6)	0.0005 (7)
O5	0.0810 (13)	0.0671 (11)	0.0618 (11)	−0.0256 (9)	0.0189 (10)	−0.0254 (10)
N1	0.0300 (7)	0.0278 (7)	0.0450 (9)	−0.0056 (6)	0.0102 (6)	−0.0018 (6)
C1	0.0289 (8)	0.0235 (8)	0.0510 (12)	−0.0035 (6)	0.0093 (8)	−0.0023 (8)
C2	0.0388 (10)	0.0311 (9)	0.0486 (11)	−0.0100 (7)	0.0138 (8)	−0.0081 (8)
C3	0.0325 (9)	0.0339 (9)	0.0379 (10)	−0.0019 (7)	0.0102 (8)	0.0029 (8)
C4	0.0327 (9)	0.0353 (9)	0.0292 (9)	−0.0053 (7)	0.0082 (7)	0.0017 (7)
C5	0.0344 (9)	0.0444 (10)	0.0376 (10)	−0.0056 (8)	0.0033 (8)	0.0028 (9)
C6	0.0440 (11)	0.0475 (11)	0.0396 (11)	−0.0193 (9)	0.0052 (9)	−0.0022 (9)
C7	0.0582 (12)	0.0322 (9)	0.0413 (11)	−0.0149 (9)	0.0107 (10)	−0.0021 (8)
C8	0.0477 (11)	0.0311 (9)	0.0357 (10)	−0.0010 (8)	0.0076 (8)	0.0024 (8)
C9	0.0334 (9)	0.0322 (9)	0.0283 (9)	−0.0058 (7)	0.0069 (7)	0.0000 (7)
C10	0.0329 (9)	0.0326 (9)	0.0344 (10)	−0.0032 (7)	0.0072 (7)	0.0005 (7)

Geometric parameters (Å, º) top

Ca1—O1Bⁱ	2.258 (15)	O5—H5B	0.8199 (10)
Ca1—O1Bⁱⁱ	2.258 (15)	N1—C10	1.384 (2)
Ca1—O1ⁱ	2.338 (2)	N1—C3	1.396 (2)
Ca1—O1ⁱⁱ	2.338 (2)	N1—C2	1.447 (2)
Ca1—O5	2.4111 (16)	C1—C2	1.525 (3)
Ca1—O5ⁱⁱⁱ	2.4111 (16)	C2—H2A	0.9700
Ca1—O2	2.5298 (13)	C2—H2B	0.9700
Ca1—O2ⁱⁱⁱ	2.5298 (13)	C3—C4	1.492 (2)
Ca1—O1ⁱⁱⁱ	2.581 (3)	C4—C5	1.375 (2)
Ca1—O1	2.581 (3)	C4—C9	1.388 (2)
Ca1—O1B	2.99 (3)	C5—C6	1.391 (3)
Ca1—O1Bⁱⁱⁱ	2.99 (3)	C5—H5	0.9300
O1—C1	1.242 (2)	C6—C7	1.382 (3)
O1—Ca1ⁱ	2.338 (2)	C6—H6	0.9300
O1B—C1	1.45 (2)	C7—C8	1.391 (3)
O1B—Ca1ⁱ	2.258 (15)	C7—H7	0.9300
O2—C1	1.226 (2)	C8—C9	1.383 (3)
O3—C3	1.207 (2)	C8—H8	0.9300
O4—C10	1.212 (2)	C9—C10	1.485 (2)
O5—H5A	0.8200 (10)

O1Bⁱ—Ca1—O1Bⁱⁱ	67.6 (16)	O5—Ca1—O1Bⁱⁱⁱ	70.4 (6)
O1Bⁱ—Ca1—O1ⁱ	17.6 (8)	O5ⁱⁱⁱ—Ca1—O1Bⁱⁱⁱ	120.9 (3)
O1Bⁱⁱ—Ca1—O1ⁱ	82.0 (9)	O2—Ca1—O1Bⁱⁱⁱ	131.8 (5)
O1Bⁱ—Ca1—O1ⁱⁱ	82.0 (9)	O2ⁱⁱⁱ—Ca1—O1Bⁱⁱⁱ	52.5 (3)
O1Bⁱⁱ—Ca1—O1ⁱⁱ	17.6 (8)	O1ⁱⁱⁱ—Ca1—O1Bⁱⁱⁱ	11.8 (5)
O1ⁱ—Ca1—O1ⁱⁱ	97.9 (3)	O1—Ca1—O1Bⁱⁱⁱ	156.4 (4)
O1Bⁱ—Ca1—O5	162.2 (7)	O1B—Ca1—O1Bⁱⁱⁱ	166.6 (9)
O1Bⁱⁱ—Ca1—O5	108.2 (9)	C1—O1—Ca1ⁱ	153.0 (2)
O1ⁱ—Ca1—O5	167.07 (8)	C1—O1—Ca1	92.55 (18)
O1ⁱⁱ—Ca1—O5	91.40 (14)	Ca1ⁱ—O1—Ca1	114.46 (8)
O1Bⁱ—Ca1—O5ⁱⁱⁱ	108.2 (9)	C1—O1B—Ca1ⁱ	139.9 (19)
O1Bⁱⁱ—Ca1—O5ⁱⁱⁱ	162.2 (7)	C1—O1B—Ca1	72.8 (11)
O1ⁱ—Ca1—O5ⁱⁱⁱ	91.40 (14)	Ca1ⁱ—O1B—Ca1	103.1 (9)
O1ⁱⁱ—Ca1—O5ⁱⁱⁱ	167.07 (8)	C1—O2—Ca1	95.40 (11)
O5—Ca1—O5ⁱⁱⁱ	80.99 (11)	Ca1—O5—H5A	119 (2)
O1Bⁱ—Ca1—O2	120.8 (5)	Ca1—O5—H5B	131 (2)
O1Bⁱⁱ—Ca1—O2	83.9 (4)	H5A—O5—H5B	107 (3)
O1ⁱ—Ca1—O2	115.25 (7)	C10—N1—C3	112.36 (14)
O1ⁱⁱ—Ca1—O2	83.90 (6)	C10—N1—C2	122.35 (15)
O5—Ca1—O2	74.56 (6)	C3—N1—C2	125.20 (15)
O5ⁱⁱⁱ—Ca1—O2	84.00 (6)	O2—C1—O1	121.4 (2)
O1Bⁱ—Ca1—O2ⁱⁱⁱ	83.9 (4)	O2—C1—O1B	135.8 (8)
O1Bⁱⁱ—Ca1—O2ⁱⁱⁱ	120.8 (5)	O2—C1—C2	120.75 (15)
O1ⁱ—Ca1—O2ⁱⁱⁱ	83.90 (6)	O1—C1—C2	117.7 (2)
O1ⁱⁱ—Ca1—O2ⁱⁱⁱ	115.25 (7)	O1B—C1—C2	99.1 (10)
O5—Ca1—O2ⁱⁱⁱ	84.00 (6)	O2—C1—Ca1	59.82 (10)
O5ⁱⁱⁱ—Ca1—O2ⁱⁱⁱ	74.56 (6)	O1—C1—Ca1	62.24 (17)
O2—Ca1—O2ⁱⁱⁱ	151.77 (7)	O1B—C1—Ca1	78.9 (9)
O1Bⁱ—Ca1—O1ⁱⁱⁱ	80.2 (6)	C2—C1—Ca1	175.44 (13)
O1Bⁱⁱ—Ca1—O1ⁱⁱⁱ	74.1 (6)	N1—C2—C1	111.80 (15)
O1ⁱ—Ca1—O1ⁱⁱⁱ	93.58 (5)	N1—C2—H2A	109.3
O1ⁱⁱ—Ca1—O1ⁱⁱⁱ	65.54 (8)	C1—C2—H2A	109.3
O5—Ca1—O1ⁱⁱⁱ	82.03 (12)	N1—C2—H2B	109.3
O5ⁱⁱⁱ—Ca1—O1ⁱⁱⁱ	123.06 (6)	C1—C2—H2B	109.3
O2—Ca1—O1ⁱⁱⁱ	140.87 (9)	H2A—C2—H2B	107.9
O2ⁱⁱⁱ—Ca1—O1ⁱⁱⁱ	49.82 (5)	O3—C3—N1	124.85 (17)
O1Bⁱ—Ca1—O1	74.1 (6)	O3—C3—C4	129.69 (17)
O1Bⁱⁱ—Ca1—O1	80.2 (6)	N1—C3—C4	105.46 (14)
O1ⁱ—Ca1—O1	65.54 (8)	C5—C4—C9	121.49 (17)
O1ⁱⁱ—Ca1—O1	93.58 (5)	C5—C4—C3	130.51 (17)
O5—Ca1—O1	123.06 (6)	C9—C4—C3	107.99 (14)
O5ⁱⁱⁱ—Ca1—O1	82.03 (12)	C4—C5—C6	117.14 (18)
O2—Ca1—O1	49.82 (5)	C4—C5—H5	121.4
O2ⁱⁱⁱ—Ca1—O1	140.87 (9)	C6—C5—H5	121.4
O1ⁱⁱⁱ—Ca1—O1	148.96 (18)	C7—C6—C5	121.47 (17)
O1Bⁱ—Ca1—O1B	76.9 (9)	C7—C6—H6	119.3
O1Bⁱⁱ—Ca1—O1B	91.8 (5)	C5—C6—H6	119.3
O1ⁱ—Ca1—O1B	65.2 (3)	C6—C7—C8	121.36 (18)
O1ⁱⁱ—Ca1—O1B	105.4 (5)	C6—C7—H7	119.3
O5—Ca1—O1B	120.9 (3)	C8—C7—H7	119.3
O5ⁱⁱⁱ—Ca1—O1B	70.4 (6)	C9—C8—C7	116.88 (18)
O2—Ca1—O1B	52.5 (3)	C9—C8—H8	121.6
O2ⁱⁱⁱ—Ca1—O1B	131.8 (5)	C7—C8—H8	121.6
O1ⁱⁱⁱ—Ca1—O1B	156.4 (4)	C8—C9—C4	121.64 (16)
O1—Ca1—O1B	11.8 (5)	C8—C9—C10	130.22 (17)
O1Bⁱ—Ca1—O1Bⁱⁱⁱ	91.8 (5)	C4—C9—C10	108.11 (15)
O1Bⁱⁱ—Ca1—O1Bⁱⁱⁱ	76.9 (9)	O4—C10—N1	124.03 (16)
O1ⁱ—Ca1—O1Bⁱⁱⁱ	105.4 (5)	O4—C10—C9	129.90 (17)
O1ⁱⁱ—Ca1—O1Bⁱⁱⁱ	65.2 (3)	N1—C10—C9	106.06 (14)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···O4^iv	0.82 (1)	2.10 (1)	2.907 (2)	171 (3)
O5—H5B···O4^v	0.82 (1)	2.49 (2)	3.095 (2)	131 (2)
C8—H8···O2^vi	0.93	2.47	3.318 (2)	151

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

Experimental details

Crystal data
Chemical formula	[Ca(C₁₀H₆NO₄)₂(H₂O)₂]
M_r	484.43
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	32.752 (1), 9.0435 (3), 6.9753 (3)
β (°)	99.020 (2)
V (Å³)	2040.48 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.37
Crystal size (mm)	0.34 × 0.32 × 0.32

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2008a)
T_min, T_max	0.884, 0.890
No. of measured, independent and observed [I > 2σ(I)] reflections	12481, 2339, 1847
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.102, 1.04
No. of reflections	2339
No. of parameters	160
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.28, −0.23

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), Mercury (Macrae et al., 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···O4ⁱ	0.82 (1)	2.095 (6)	2.907 (2)	171 (3)
O5—H5B···O4ⁱⁱ	0.82 (1)	2.49 (2)	3.095 (2)	131 (2)
C8—H8···O2ⁱⁱⁱ	0.93	2.47	3.318 (2)	151

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

Acknowledgements

SS is grateful to the University of Hong Kong for providing facilities for crystallographic studies.

References

Barooah, N., Sarma, R. J., Batsanov, A. S. & Baruah, J. B. (2006). Polyhedron, 25, 17–24. Web of Science CSD CrossRef CAS Google Scholar
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Sheldrick, G. M. (2008b). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar

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