Strontium diibuprofenate dihydrate, strontium malonate sesquihydrate, strontium diascorbate dihydrate and strontium 2-oxidobenzoate hydrate at 120 K

Four strontium(II) salts with organic acids have been studied. Poly[diaquadi-[mu]-ibuprofenato-strontium(II)] or poly­[diaqua­bis[[mu]-2-(4-isobutyl­phen­yl)­propionato]­strontium(II)], [Sr(C₁₃H₁₇O₂)₂(H₂O)₂]_n, crystallizes with eight-coordinated Sr atoms. The coordination polyhedra are inter­connected by edge-sharing to form chains. The Sr coordination chains are packed into layers, which are stacked by van der Waals inter­actions. Poly[[mu]-aqua-diaquadi-[mu]-malonato-distrontium(II)], [Sr₂(C₃H₂O₄)₂(H₂O)₃]_n, crystallizes with nine-coordinated Sr atoms three-dimensionally inter­connected into a framework structure. One of the two crystallographically independent water mol­ecules is located on a twofold axial site. catena-Poly[[diaqua­(ascorbato)strontium(II)]-[mu]-ascorbato], [Sr(C₆H₇O₆)₂(H₂O)₂]_n, crystallizes with isolated eight-coordinated Sr polyhedra. One of the ascorbate ligands bridges two Sr atoms, forming zigzag polyhedral ascorbate chains. These chains are tied together by a three-dimensional hydrogen-bonding network. Poly[aqua-[mu]-2-oxidobenzoato-strontium(II)], [Sr(C₇H₄O₃)(H₂O)]_n, crystallizes with eight-coordinated Sr atoms. The polyhedra are inter­connected by face- and edge-sharing into layers. These layers are stacked by van der Waals forces between the protruding 2-oxidobenzoate ligands.

S1. Comment

In recent years, it has been found that Sr has a significant influence on the development and growth of bone, and the effect of dose on bone structure has been investigated in great detail (Schrooten et al., 2003). These investigations have led to a growing interest in strontium(II) salts, their crystal structures and synthetic methods that may provide products of high yield and purity (Christgau et al., 2005). The present paper presents a structural investigation of four such new strontium(II) salts with organic acids.

In strontium diibuprofenate dihydrate, (I), the Sr atom is eight-coordinated in a distorted square antiprism by six O atoms from the asymmetric unit and two additional carboxylate O atoms from neighbouring ibuprofenates (O11* and O31* in Fig. 1). The ibuprofenate pair in an asymmetric unit shown in Fig. 1 have the same absolute configuration. The strontium polyhedra share edges to form chains in the a direction (Fig. 5). The chains are stacked in layers in the ab plane with the ibuprofenates protruding in the c direction. These layers are in turn stacked in the c direction, in both cases by van der Waals interactions only. Viewed in the a direction (Fig. 5), the strontium ibuprofenate complexes appear slightly tilted. This causes a difference in the packing of the two independent ibuprofenates. One ibuprofenate ion, (IA), extends further towards the next layer than the other, (IB), which is more confined to the space between the chains. This difference in packing may explain the observation of larger disorder of the terminal methyl groups of the (IA) ibuprofenate ion. The torsion angles of the isobutanyl and the propionate ends are very similar when comparing the two ibuprofenates (Table 9). Compared with the torsion angles of ibuprofen (Hansen et al., 2003), the differences in the isobutyl ends are minor, 6–8°, while the propionate ends show differences of 26–47° (Table 9). The ibuprofen conformations minimize the benzene–propionate interactions, while in (I) the coordination and packing requirements cause more strained conformations. Hydrogen bonding plays a minor role in the packing. Only one H atom of each water molecule is employed in hydrogen bonding (Table 2), and hydrogen bonding is, because of the bulkiness of the ibuprofenates, restricted to carboxylic O atoms in neighbouring strontium polyhedra within a polyhedral chain.

In strontium malonate sesquihydrate, (II), the Sr atom is nine-coordinated by all available malonate and water O atoms. The irregular polyhedra are connected by edge and face sharing into a three-dimensional framework structure. Atoms O3 and O6 are still unshared between polyhedra. The channel system thus created is occupied by the malonate carbon backbone (Fig. 6). All water H atoms are involved in hydrogen bonding to carboxylic O atoms (Table 4). By comparison, Sr malonate anhydrate (Briggman & Oskarsson, 1977) forms a similar three-dimensional polyhedral network, but all O atoms are shared between Sr polyhedra. This configuration results in a relatively dense packing, D_x = 2.78 Mg m⁻³, compared with 2.48 Mg m⁻³ in (II). The higher degree of interconnections and denser packing is the most probable cause of the irreversible dehydration of (II).

In strontium diascorbate dihydrate, (III), the Sr atom is eight-coordinated by ascorbate and water O atoms, forming isolated irregular polyhedra. The two independent ascorbate ions are coordinated differently. Ascorbate ion (IIIA) uses atoms O11, O13, O15 and O16 to coordinate two Sr ions, thus linking the Sr polyhedra into zigzagging chains in the b direction, while ascorbate ion (IIIB) has a one-sided coordination through atoms O25 and O26 (Fig. 7). The ascorbate polyhedral chains are further connected by a three-dimensional hydrogen-bonding network. The conformations of the independent ascorbate ions are different; the O14—C17—C18—C19 [for (IA)] and O24—C27—C28—C29 [for (IIIB)] torsion angles are −69.9 (2) and 176.4 (2)°, respectively. The O14—C17—C18—C19 (IIIA) torsion angle is similar to the corresponding torsion angles in ascorbic acid, −68.3 (3) and −55.5 (3)° for its two independent molecules (Hvoslef, 1968). The O15—C18—C18—O16 [(IIIA)] and O25—C28—C29—O26 [(IIIB)] torsion angles are 48.8 (2) and 50.4 (2)°, respectively, bringing them into almost eclipsed conformations and allowing for simultaneous Sr coordination of the O pairs. In ascorbic acid, the corresponding O—C—C—O torsion angles are 171.2 (3) and 171.4 (3)°, i.e. close to staggered conformations (Hvoslef, 1968). All H-atom donors are involved in hydrogen bonding, forming a three-dimensional network. It is interesting to note that the shortest hydrogen bonds (H···A < 2 Å) all involve uncoordinated O atoms from (IIIB) (Table 6), which may be explained by a higher packing/conformational flexibility of the one-sided Sr coordination of (IIIB).

In strontium 2-oxidobenzoate hydrate, (IV), the Sr atom is eight-coordinated in an approximately square antiprismatic cofiguration. The antiprisms are pair-wise connected through face-sharing, and these pairs are further connected by edge-sharing into layers in the ac plane (Fig. 8). The 2-oxidobenzoates protrude from the layers and connect them through van der Waals forces in the b direction. By comparison, the Sr disalicylate dihydrate (Debuyst et al. 1979) forms polyhedral chains, where the hydroxy group takes part in a three-dimensional hydrogen-bonding network connecting these chains. In (IV) only one of the water H-atom donors, H4B, participates in a conventional hydrogen bond. However, atom H4A points towards the center of a neighbouring benzene ring with a distance of 2.83 (3) Å to the ring center (A) and an O4—H4A···A angle of 154 (3)°.

Strontium(II) salts with organic acids are generally octa- to decacoordinated by O atoms, with coordination distances in the range 2.4–3.0 Å. The Sr polyhedra show various degrees of condensation depending on the number of available carboxylic and water O atoms, and the size of the organic group. The resulting structures are thus observed with isolated Sr polyhedra as in (III), polyhedra connected in chains as in (I), layers as in (IV) or three-dimensional networks as in (II). The average Sr—O distance is primarily determined by the coordination number as seen for (II), viz. 2.6803 (4) Å with nine-coordination, and 2.5940 (9), 2.5927 (6) and 2.6034 (7) Å for the eight-coordinated (I), (III) and (IV), respectively. An increasing degree of condensation cause a minor increase in the average Sr—O distances when comparing the eight-coordinated complexes [2.5927 (6) Å for (III), isolated; 2.5940 (9) Å for (I), chains; and 2.6034 (7) Å for (IV), layer]s.

S2. Experimental

For the preparation of (I), solid strontium carbonate was added to a saturated solution of racemic ibuprofen at 317 K in a molar ratio of 1:2. The product was obtained in high yield and purity after cooling to room temperature and filtration. For the preparation of (II), an equimolar amount of solid strontium carbonate was added to a saturated aqueous solution of malonic acid at 303–317 K. The product precipitated upon cooling to room temperature. Consequtive cycles of evaporation of the solvent below 343 K followed by filtration at room temperature resulted in yields between 90 and 100%. Heating of the product above 343 K resulted in complete dehydration and irreversible transformation to anhydrous strontium malonate. For the preparation of (III), strontium chloride hexahydrate was added to a solution of sodium ascorbate in a molar ratio of 1:2. More strontium chloride hexahydrate, approximately 100 g in total, and sodium ascorbate, approximately 77 g in total, were added to the solution at 317 K until a transparent yellow syrup was obtained. The syrup was suction filtered for 12 h and the product was obtained by drying the syrup in a desiccator. The final product was a white powder with a yellow tarnish, while the selected single crystals appeared colorless. The product was also obtained by pouring an aqueous solution of ascorbic acid and powdered strontium carbonate into a large volume of acetone according to the procedure of Ruskin & Merrill (1947). For the preparation of (IV), powdered strontium carbonate was added to an equimolar amount of a saturated solution of salicylic acid at 313 K. Strontium 2-oxidobenzoate hydrate was obtained in high yield and purity as a pecipitate on cooling to 293 K.

S3. Refinement

In all refinements all H-atom sites were initially located in difference Fourier maps and refined freely. In the final cycles, H atoms of the CH, CH₂ and CH₃ groups were placed in calculated positions, with C—H = 0.93 (aromatic CH), 0.98 (aliphatic CH), 0.97 (CH₂) and 0.96 Å (CH₃), and refined as riding atoms. In water molecules and OH groups the O—H distances were restrained to 0.82 (2) Å. The displacement parameters were set to 1.2 (CH, CH₂ and CH₃) or 1.5 (OH) times U_eq of the corresponding C or O atoms. In (I), several of the terminal methyl groups show signs of disorder. Several models with split positions for atoms C19, C22 and C23 were tried, with up to ten different positions. Using 353 parameters with mixed anisotrpic and isotropic displacement parameters for the different split sites, but not including the corresponding H-atom positions, resulted in an wR2 value of 0.1536, while the unsplit model including H-atom positions with 310 parameters resulted in an wR2 value of 0.1450. The unsplit model was therefore judged as appropriate on the present level of experimental resolution. The absolute structure determination of (III) is based on 2226 Bijvoet pairs.

Computing details

For all compounds, data collection: SMART (Bruker, 1999); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus and SADABS (Sheldrick, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and ATOMS (Dowty, 2000); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The asymmetric unit of (I), showing 75% probability displacement ellipsoids and the atomic numbering. H atoms have been omitted for clarity. Atoms labelled with an asterix (*) are at the symmetry positions indicated in Table 1.
	Fig. 2. The asymmetric unit of (II), showing 75% probability displacement ellipsoids and the atomic numbering. Atoms labelled with an asterix (*) are at the symmetry positions indicated in Table 3.
	Fig. 3. The asymmetric unit of (III), showing 75% probability displacement ellipsoids and the atomic numbering. Atoms labelled with an asterix (*) are at the symmetry positions indicated in Table 5.
	Fig. 4. The asymmetric unit of (IV), showing 75% probability displacement ellipsoids and the atomic numbering. Atoms labelled with an asterix (*) are at the symmetry positions indicated in Table 7.
	Fig. 5. The crystal packing of (I), viewed down the a axis. The Sr eight-coordination is shown as polyhedra. H atoms have been omitted for clarity.
	Fig. 6. The crystal packing of (II), viewed down the b axis. The Sr nine-coordination is shown as polyhedra. H atoms have been omitted for clarity.
	Fig. 7. The crystal packing of (III), viewed down the a axis. The Sr eight-coordination is shown as polyhedra. H atoms have been omitted for clarity.
	Fig. 8. The crystal packing of (IV), viewed down the a axis. The Sr eight-coordination is shown as polyhedra. H atoms have been omitted for clarity.

(I) poly[diaquabis[µ-2-(4-isobutylphenyl)propionato]strontium(II)]

Crystal data

[Sr(C13H17O2)2(H2O)2]	Z = 2
Mr = 534.18	F(000) = 560
Triclinic, P1	Dx = 1.262 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.9116 (7) Å	Cell parameters from 3382 reflections
b = 10.487 (1) Å	θ = 2.3–27.6°
c = 18.2493 (17) Å	µ = 1.95 mm^−1
α = 86.088 (2)°	T = 120 K
β = 79.784 (2)°	Plate, colorless
γ = 70.605 (2)°	0.35 × 0.06 × 0.03 mm
V = 1405.5 (2) Å^3

Data collection

Bruker SMART APEX diffractometer	8160 independent reflections
Radiation source: fine-focus sealed tube	5038 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
ω scan, frame data integration	θmax = 31.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −11→11
Tmin = 0.548, Tmax = 0.944	k = −15→14
19139 measured reflections	l = −26→26

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)] = 0.058	Hydrogen site location: difference Fourier map
wR(F^2) = 0.145	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ^2(Fo^2) + (0.0724P)^2] where P = (Fo^2 + 2Fc^2)/3
8160 reflections	(Δ/σ)max = 0.001
310 parameters	Δρmax = 0.79 e Å^−3
4 restraints	Δρmin = −0.44 e Å^−3

Special details

Experimental. Oxford Cryosystem liquid nitrogen cryostream cooler

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 > 2σ(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
Sr1	0.76760 (4)	0.44979 (4)	0.012433 (17)	0.03868 (12)
O3	0.8918 (3)	0.3797 (3)	0.13485 (14)	0.0453 (6)
H31	0.976 (4)	0.403 (4)	0.139 (2)	0.068*
H32	0.819 (5)	0.400 (4)	0.1733 (16)	0.068*
O4	0.7381 (3)	0.2360 (3)	−0.03646 (15)	0.0476 (6)
H41	0.641 (4)	0.253 (4)	−0.049 (2)	0.071*
H42	0.815 (5)	0.179 (3)	−0.065 (2)	0.071*
O11	0.5234 (3)	0.5662 (3)	−0.08197 (13)	0.0463 (6)
O12	0.8107 (3)	0.5425 (3)	−0.12268 (13)	0.0464 (6)
C11	0.5004 (4)	0.5821 (4)	−0.24407 (18)	0.0370 (8)
C12	0.5251 (4)	0.4451 (4)	−0.23561 (19)	0.0405 (8)
H12	0.5999	0.3940	−0.2029	0.049*
C13	0.4399 (5)	0.3828 (4)	−0.27514 (18)	0.0424 (8)
H13	0.4583	0.2907	−0.2685	0.051*
C14	0.3282 (5)	0.4564 (4)	−0.32417 (18)	0.0417 (8)
C15	0.3020 (5)	0.5935 (4)	−0.33199 (19)	0.0427 (8)
H15	0.2263	0.6450	−0.3643	0.051*
C16	0.3874 (5)	0.6554 (4)	−0.29224 (18)	0.0405 (8)
H16	0.3678	0.7477	−0.2983	0.049*
C17	0.6473 (4)	0.5823 (4)	−0.13118 (19)	0.0409 (8)
C18	0.5944 (6)	0.6549 (4)	−0.2032 (2)	0.0534 (10)
H18	0.5035	0.7425	−0.1884	0.064*
C19	0.7462 (8)	0.6859 (7)	−0.2536 (3)	0.110 (2)
H19A	0.7035	0.7314	−0.2975	0.132*
H19B	0.8430	0.6032	−0.2673	0.132*
H19C	0.7899	0.7429	−0.2283	0.132*
C20	0.2412 (7)	0.3893 (5)	−0.3721 (2)	0.0651 (12)
H20A	0.1134	0.4414	−0.3690	0.078*
H20B	0.2500	0.2994	−0.3526	0.078*
C21	0.3331 (10)	0.3791 (6)	−0.4542 (2)	0.094 (2)
H21	0.3255	0.4706	−0.4724	0.113*
C22	0.2258 (13)	0.3248 (8)	−0.4996 (3)	0.177 (5)
H22A	0.1013	0.3823	−0.4927	0.212*
H22B	0.2320	0.2348	−0.4830	0.212*
H22C	0.2773	0.3236	−0.5514	0.212*
C23	0.5376 (11)	0.2925 (6)	−0.4625 (3)	0.129 (3)
H23A	0.5984	0.3328	−0.4345	0.155*
H23B	0.5917	0.2887	−0.5141	0.155*
H23C	0.5488	0.2027	−0.4439	0.155*
O31	0.8989 (3)	0.6557 (3)	0.02531 (13)	0.0481 (6)
O32	0.6074 (3)	0.6942 (3)	0.06225 (14)	0.0490 (6)
C31	0.8393 (4)	0.8894 (3)	0.12206 (17)	0.0351 (7)
C32	0.8892 (5)	1.0051 (4)	0.1233 (2)	0.0446 (8)
H32A	0.8533	1.0742	0.0888	0.053*
C33	0.9909 (5)	1.0190 (4)	0.1747 (2)	0.0473 (9)
H33	1.0230	1.0967	0.1742	0.057*
C34	1.0450 (5)	0.9188 (4)	0.22697 (19)	0.0427 (8)
C35	0.9992 (5)	0.8025 (3)	0.22540 (18)	0.0390 (8)
H35	1.0367	0.7334	0.2596	0.047*
C36	0.8985 (4)	0.7874 (3)	0.17374 (18)	0.0367 (7)
H36	0.8701	0.7082	0.1736	0.044*
C37	0.7435 (4)	0.7334 (4)	0.05112 (18)	0.0414 (8)
C38	0.7215 (5)	0.8792 (4)	0.0677 (2)	0.0456 (9)
H38	0.7601	0.9207	0.0207	0.055*
C39	0.5246 (6)	0.9680 (5)	0.0984 (3)	0.0775 (14)
H39A	0.4450	0.9646	0.0650	0.093*
H39B	0.5207	1.0597	0.1026	0.093*
H39C	0.4862	0.9346	0.1465	0.093*
C40	1.1434 (6)	0.9389 (4)	0.2874 (2)	0.0555 (10)
H40A	1.2437	0.9697	0.2647	0.067*
H40B	1.1934	0.8530	0.3119	0.067*
C41	1.0180 (7)	1.0416 (4)	0.3455 (2)	0.0614 (12)
H41A	0.9715	1.1280	0.3196	0.074*
C42	1.1266 (9)	1.0630 (5)	0.4018 (3)	0.097 (2)
H42A	1.2278	1.0883	0.3762	0.117*
H42B	1.1703	0.9807	0.4294	0.117*
H42C	1.0501	1.1335	0.4355	0.117*
C43	0.8562 (7)	1.0009 (5)	0.3824 (3)	0.0766 (14)
H43A	0.7930	0.9869	0.3449	0.092*
H43B	0.7757	1.0712	0.4152	0.092*
H43C	0.8973	0.9187	0.4103	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.01726 (14)	0.0745 (3)	0.03160 (17)	−0.02246 (14)	−0.00314 (11)	−0.01354 (14)
O3	0.0255 (12)	0.0823 (18)	0.0360 (13)	−0.0290 (13)	−0.0001 (10)	−0.0079 (12)
O4	0.0209 (12)	0.0727 (18)	0.0510 (16)	−0.0147 (12)	−0.0039 (11)	−0.0207 (13)
O11	0.0240 (11)	0.0844 (18)	0.0376 (13)	−0.0274 (12)	−0.0026 (10)	−0.0062 (12)
O12	0.0225 (11)	0.0815 (17)	0.0426 (14)	−0.0266 (12)	−0.0022 (10)	−0.0100 (12)
C11	0.0260 (16)	0.057 (2)	0.0310 (17)	−0.0178 (15)	−0.0036 (13)	−0.0036 (15)
C12	0.0287 (17)	0.055 (2)	0.0346 (18)	−0.0092 (15)	−0.0039 (14)	−0.0028 (15)
C13	0.049 (2)	0.045 (2)	0.0319 (18)	−0.0161 (17)	−0.0018 (16)	−0.0070 (15)
C14	0.0418 (19)	0.055 (2)	0.0307 (17)	−0.0202 (17)	−0.0005 (15)	−0.0120 (15)
C15	0.0400 (19)	0.055 (2)	0.0328 (18)	−0.0115 (17)	−0.0107 (15)	−0.0060 (15)
C16	0.0417 (19)	0.049 (2)	0.0330 (18)	−0.0166 (16)	−0.0060 (15)	−0.0038 (15)
C17	0.0302 (17)	0.067 (2)	0.0358 (18)	−0.0283 (17)	−0.0047 (14)	−0.0099 (16)
C18	0.053 (2)	0.082 (3)	0.045 (2)	−0.045 (2)	−0.0154 (18)	0.0029 (19)
C19	0.122 (5)	0.202 (7)	0.066 (3)	−0.128 (5)	−0.041 (3)	0.040 (4)
C20	0.088 (3)	0.076 (3)	0.049 (2)	−0.044 (3)	−0.019 (2)	−0.011 (2)
C21	0.192 (7)	0.086 (4)	0.041 (3)	−0.085 (4)	−0.035 (3)	0.003 (2)
C22	0.374 (14)	0.180 (7)	0.071 (4)	−0.193 (9)	−0.081 (6)	0.002 (4)
C23	0.211 (9)	0.091 (4)	0.060 (4)	−0.042 (5)	0.039 (4)	−0.025 (3)
O31	0.0209 (11)	0.0852 (18)	0.0431 (14)	−0.0214 (12)	−0.0013 (10)	−0.0241 (12)
O32	0.0204 (11)	0.0809 (18)	0.0507 (15)	−0.0218 (11)	−0.0019 (10)	−0.0183 (13)
C31	0.0254 (15)	0.048 (2)	0.0304 (17)	−0.0089 (14)	−0.0031 (13)	−0.0063 (14)
C32	0.044 (2)	0.047 (2)	0.041 (2)	−0.0104 (17)	−0.0129 (16)	−0.0009 (16)
C33	0.051 (2)	0.046 (2)	0.048 (2)	−0.0170 (18)	−0.0087 (18)	−0.0104 (17)
C34	0.0404 (19)	0.052 (2)	0.0380 (19)	−0.0139 (16)	−0.0101 (16)	−0.0137 (16)
C35	0.0383 (18)	0.044 (2)	0.0331 (18)	−0.0089 (15)	−0.0086 (15)	−0.0057 (14)
C36	0.0330 (17)	0.0432 (19)	0.0351 (18)	−0.0123 (15)	−0.0053 (14)	−0.0104 (14)
C37	0.0216 (15)	0.075 (2)	0.0291 (17)	−0.0141 (16)	−0.0081 (13)	−0.0092 (16)
C38	0.0303 (17)	0.069 (3)	0.039 (2)	−0.0159 (17)	−0.0148 (15)	0.0052 (17)
C39	0.047 (3)	0.091 (3)	0.096 (4)	−0.015 (2)	−0.028 (3)	−0.014 (3)
C40	0.063 (3)	0.059 (2)	0.052 (2)	−0.020 (2)	−0.022 (2)	−0.0124 (18)
C41	0.089 (3)	0.049 (2)	0.050 (2)	−0.020 (2)	−0.025 (2)	−0.0102 (18)
C42	0.166 (6)	0.087 (4)	0.067 (3)	−0.058 (4)	−0.054 (4)	−0.011 (3)
C43	0.096 (4)	0.078 (3)	0.049 (3)	−0.024 (3)	0.002 (3)	−0.017 (2)

Geometric parameters (Å, º)

Sr1—O11^i	2.476 (2)	C22—H22A	0.9600
Sr1—O31^ii	2.486 (2)	C22—H22B	0.9600
Sr1—O3	2.563 (3)	C22—H22C	0.9600
Sr1—O4	2.563 (3)	C23—H23A	0.9600
Sr1—O12	2.595 (2)	C23—H23B	0.9600
Sr1—O32	2.599 (3)	C23—H23C	0.9600
Sr1—O31	2.728 (2)	O31—C37	1.257 (4)
Sr1—O11	2.742 (2)	O32—C37	1.255 (4)
O3—H31	0.804 (18)	C31—C36	1.393 (5)
O3—H32	0.815 (19)	C31—C32	1.397 (5)
O4—H41	0.798 (19)	C31—C38	1.508 (4)
O4—H42	0.829 (19)	C32—C33	1.384 (5)
O11—C17	1.254 (4)	C32—H32A	0.9300
O12—C17	1.254 (4)	C33—C34	1.380 (5)
C11—C16	1.376 (5)	C33—H33	0.9300
C11—C12	1.386 (5)	C34—C35	1.386 (5)
C11—C18	1.531 (5)	C34—C40	1.520 (5)
C12—C13	1.390 (5)	C35—C36	1.385 (4)
C12—H12	0.9300	C35—H35	0.9300
C13—C14	1.382 (5)	C36—H36	0.9300
C13—H13	0.9300	C37—C38	1.526 (5)
C14—C15	1.385 (5)	C38—C39	1.551 (6)
C14—C20	1.533 (5)	C38—H38	0.9800
C15—C16	1.390 (5)	C39—H39A	0.9600
C15—H15	0.9300	C39—H39B	0.9600
C16—H16	0.9300	C39—H39C	0.9600
C17—C18	1.527 (5)	C40—C41	1.530 (6)
C18—C19	1.489 (6)	C40—H40A	0.9700
C18—H18	0.9800	C40—H40B	0.9700
C19—H19A	0.9600	C41—C43	1.514 (6)
C19—H19B	0.9600	C41—C42	1.523 (6)
C19—H19C	0.9600	C41—H41A	0.9800
C20—C21	1.540 (6)	C42—H42A	0.9600
C20—H20A	0.9700	C42—H42B	0.9600
C20—H20B	0.9700	C42—H42C	0.9600
C21—C22	1.537 (7)	C43—H43A	0.9600
C21—C23	1.556 (9)	C43—H43B	0.9600
C21—H21	0.9800	C43—H43C	0.9600
H31—O3—H32	107 (4)	H23B—C23—H23C	109.5
H41—O4—H42	109 (4)	C36—C31—C32	117.5 (3)
C16—C11—C12	118.1 (3)	C36—C31—C38	122.1 (3)
C16—C11—C18	118.7 (3)	C32—C31—C38	120.3 (3)
C12—C11—C18	123.2 (3)	C33—C32—C31	121.3 (3)
C11—C12—C13	121.1 (3)	C33—C32—H32A	119.3
C11—C12—H12	119.4	C31—C32—H32A	119.3
C13—C12—H12	119.4	C34—C33—C32	120.7 (3)
C14—C13—C12	120.6 (3)	C34—C33—H33	119.6
C14—C13—H13	119.7	C32—C33—H33	119.6
C12—C13—H13	119.7	C33—C34—C35	118.4 (3)
C13—C14—C15	118.2 (3)	C33—C34—C40	120.7 (3)
C13—C14—C20	121.9 (3)	C35—C34—C40	120.8 (3)
C15—C14—C20	119.8 (3)	C36—C35—C34	121.2 (3)
C14—C15—C16	120.9 (3)	C36—C35—H35	119.4
C14—C15—H15	119.5	C34—C35—H35	119.4
C16—C15—H15	119.5	C35—C36—C31	120.8 (3)
C11—C16—C15	121.0 (3)	C35—C36—H36	119.6
C11—C16—H16	119.5	C31—C36—H36	119.6
C15—C16—H16	119.5	O32—C37—O31	121.5 (3)
O11—C17—O12	122.4 (3)	O32—C37—C38	119.9 (3)
O11—C17—C18	118.0 (3)	O31—C37—C38	118.6 (3)
O12—C17—C18	119.6 (3)	C31—C38—C37	112.8 (3)
C19—C18—C17	113.9 (3)	C31—C38—C39	106.8 (3)
C19—C18—C11	111.8 (3)	C37—C38—C39	114.9 (3)
C17—C18—C11	112.3 (3)	C31—C38—H38	107.3
C19—C18—H18	106.0	C37—C38—H38	107.3
C17—C18—H18	106.0	C39—C38—H38	107.3
C11—C18—H18	106.0	C38—C39—H39A	109.5
C18—C19—H19A	109.5	C38—C39—H39B	109.5
C18—C19—H19B	109.5	H39A—C39—H39B	109.5
H19A—C19—H19B	109.5	C38—C39—H39C	109.5
C18—C19—H19C	109.5	H39A—C39—H39C	109.5
H19A—C19—H19C	109.5	H39B—C39—H39C	109.5
H19B—C19—H19C	109.5	C34—C40—C41	112.3 (3)
C14—C20—C21	112.2 (4)	C34—C40—H40A	109.2
C14—C20—H20A	109.2	C41—C40—H40A	109.2
C21—C20—H20A	109.2	C34—C40—H40B	109.2
C14—C20—H20B	109.2	C41—C40—H40B	109.2
C21—C20—H20B	109.2	H40A—C40—H40B	107.9
H20A—C20—H20B	107.9	C43—C41—C42	112.2 (4)
C22—C21—C20	108.8 (5)	C43—C41—C40	111.9 (3)
C22—C21—C23	113.1 (6)	C42—C41—C40	109.7 (4)
C20—C21—C23	111.2 (4)	C43—C41—H41A	107.6
C22—C21—H21	107.8	C42—C41—H41A	107.6
C20—C21—H21	107.8	C40—C41—H41A	107.6
C23—C21—H21	107.8	C41—C42—H42A	109.5
C21—C22—H22A	109.5	C41—C42—H42B	109.5
C21—C22—H22B	109.5	H42A—C42—H42B	109.5
H22A—C22—H22B	109.5	C41—C42—H42C	109.5
C21—C22—H22C	109.5	H42A—C42—H42C	109.5
H22A—C22—H22C	109.5	H42B—C42—H42C	109.5
H22B—C22—H22C	109.5	C41—C43—H43A	109.5
C21—C23—H23A	109.5	C41—C43—H43B	109.5
C21—C23—H23B	109.5	H43A—C43—H43B	109.5
H23A—C23—H23B	109.5	C41—C43—H43C	109.5
C21—C23—H23C	109.5	H43A—C43—H43C	109.5
H23A—C23—H23C	109.5	H43B—C43—H43C	109.5

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H31···O12^ii	0.80 (2)	1.92 (2)	2.706 (3)	165 (4)
O4—H41···O32^i	0.80 (2)	1.91 (2)	2.704 (3)	171 (5)

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

(II) Poly[µ-aqua-diaquadi-µ-malonato-distrontium(II)]

Crystal data

[Sr2(C3H2O4)2(H2O)3]	F(000) = 840
Mr = 433.38	Dx = 2.480 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 5770 reflections
a = 14.3345 (9) Å	θ = 3.0–30.9°
b = 7.3458 (5) Å	µ = 9.25 mm^−1
c = 11.5075 (7) Å	T = 120 K
β = 106.710 (1)°	Irregular, colorless
V = 1160.55 (13) Å^3	0.33 × 0.30 × 0.08 mm
Z = 4

Data collection

Bruker SMART APEX diffractometer	1708 independent reflections
Radiation source: fine-focus sealed tube	1630 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω scan, frame data integration	θmax = 30.7°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −19→19
Tmin = 0.06, Tmax = 0.48	k = −10→10
7363 measured reflections	l = −16→15

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.016	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.041	w = 1/[σ^2(Fo^2) + (0.0238P)^2 + 0.6829P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.003
1708 reflections	Δρmax = 0.55 e Å^−3
97 parameters	Δρmin = −0.49 e Å^−3
3 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0044 (2)

Special details

Experimental. Oxford Cryosystem liquid nitrogen cryostream cooler

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 > 2σ(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
Sr1	0.587276 (8)	0.183425 (15)	0.420747 (9)	0.00682 (6)
O5	0.5000	−0.06214 (19)	0.2500	0.0107 (2)
H5	0.5347 (14)	−0.132 (2)	0.2248 (18)	0.016*
O6	0.55766 (7)	0.53002 (14)	0.39529 (9)	0.01319 (19)
H6A	0.5016 (11)	0.551 (3)	0.3629 (17)	0.020*
H6B	0.5791 (14)	0.617 (3)	0.4375 (17)	0.020*
O1	0.59628 (7)	0.26538 (14)	0.20622 (8)	0.01000 (18)
O2	0.59520 (7)	0.12878 (14)	0.03327 (8)	0.01064 (18)
O3	0.88290 (7)	0.24146 (14)	0.35119 (8)	0.01177 (18)
O4	0.75451 (7)	0.12301 (15)	0.39481 (9)	0.01383 (19)
C1	0.63950 (10)	0.18388 (15)	0.13999 (12)	0.0077 (2)
C2	0.74886 (9)	0.15711 (18)	0.18314 (12)	0.0099 (2)
H2A	0.7785	0.2449	0.1417	0.012*
H2B	0.7634	0.0369	0.1581	0.012*
C3	0.79744 (10)	0.17521 (16)	0.31886 (12)	0.0089 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.00625 (8)	0.00896 (8)	0.00554 (8)	0.00000 (3)	0.00218 (5)	0.00040 (3)
O5	0.0113 (6)	0.0106 (6)	0.0112 (6)	0.000	0.0051 (5)	0.000
O6	0.0093 (4)	0.0128 (5)	0.0160 (4)	−0.0008 (4)	0.0013 (4)	−0.0037 (4)
O1	0.0095 (4)	0.0130 (4)	0.0084 (4)	0.0018 (3)	0.0039 (3)	0.0006 (3)
O2	0.0112 (4)	0.0117 (4)	0.0076 (4)	0.0001 (3)	0.0005 (3)	−0.0013 (3)
O3	0.0088 (4)	0.0161 (5)	0.0098 (4)	−0.0022 (4)	0.0017 (3)	−0.0016 (4)
O4	0.0089 (4)	0.0225 (5)	0.0107 (4)	0.0022 (4)	0.0038 (3)	0.0042 (4)
C1	0.0071 (5)	0.0077 (6)	0.0080 (5)	−0.0011 (4)	0.0018 (5)	0.0016 (4)
C2	0.0068 (5)	0.0150 (6)	0.0084 (5)	0.0005 (4)	0.0027 (4)	−0.0014 (4)
C3	0.0082 (6)	0.0094 (6)	0.0092 (6)	0.0021 (4)	0.0023 (5)	−0.0007 (4)

Geometric parameters (Å, º)

Sr1—O4	2.5386 (10)	O6—H6A	0.797 (15)
Sr1—O1	2.5801 (9)	O6—H6B	0.805 (15)
Sr1—O6	2.5839 (10)	O1—C1	1.2627 (15)
Sr1—O3^i	2.5942 (9)	O2—C1	1.2754 (16)
Sr1—O2^ii	2.6201 (10)	O3—C3	1.2704 (16)
Sr1—O1^iii	2.6850 (10)	O4—C3	1.2644 (16)
Sr1—O5	2.6956 (9)	C1—C2	1.5149 (18)
Sr1—O2^iii	2.8423 (10)	C2—C3	1.5219 (18)
Sr1—O4^i	2.9836 (11)	C2—H2A	0.9700
O5—H5	0.824 (14)	C2—H2B	0.9700
H6A—O6—H6B	107 (2)	C1—C2—H2B	108.1
O1—C1—O2	122.46 (12)	C3—C2—H2B	108.1
O1—C1—C2	120.31 (11)	H2A—C2—H2B	107.3
O2—C1—C2	117.14 (11)	O4—C3—O3	122.25 (12)
C1—C2—C3	116.75 (10)	O4—C3—C2	120.85 (12)
C1—C2—H2A	108.1	O3—C3—C2	116.88 (11)
C3—C2—H2A	108.1

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5···O3^iv	0.82 (1)	1.90 (1)	2.7165 (12)	170 (2)
O6—H6A···O3^v	0.80 (2)	2.18 (2)	2.8662 (14)	145 (2)
O6—H6B···O2^vi	0.81 (2)	2.15 (2)	2.9328 (14)	164 (2)

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

(III) catena-Poly[[diaqua(ascorbato)strontium(II)]-µ-ascorbato]

Crystal data

[Sr(C6H7O6)2(H2O)2]	F(000) = 480
Mr = 473.88	Dx = 1.906 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 6673 reflections
a = 6.4358 (5) Å	θ = 2.5–30.7°
b = 16.1040 (13) Å	µ = 3.34 mm^−1
c = 8.3646 (7) Å	T = 120 K
β = 107.696 (1)°	Irregular, colorless
V = 825.90 (12) Å^3	0.28 × 0.05 × 0.04 mm
Z = 2

Data collection

Bruker SMART APEX diffractometer	4728 independent reflections
Radiation source: fine-focus sealed tube	4507 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω scan, frame data integration	θmax = 30.9°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −9→9
Tmin = 0.455, Tmax = 0.878	k = −22→23
10978 measured reflections	l = −12→11

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.025	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.057	w = 1/[σ^2(Fo^2) + (0.0321P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
4728 reflections	Δρmax = 0.73 e Å^−3
274 parameters	Δρmin = −0.28 e Å^−3
11 restraints	Absolute structure: Flack (1983), 2035 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.017 (4)

Special details

Experimental. Oxford Cryosystem liquid nitrogen cryostream cooler

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
Sr1	0.02286 (3)	0.889795 (13)	0.77741 (2)	0.00880 (5)
O1	−0.3373 (3)	0.87790 (10)	0.5303 (2)	0.0173 (3)
H1A	−0.367 (5)	0.8328 (14)	0.481 (4)	0.026*
H1B	−0.353 (5)	0.9149 (15)	0.464 (3)	0.026*
O2	0.4158 (3)	0.84918 (11)	0.9468 (2)	0.0178 (3)
H2A	0.456 (5)	0.8027 (13)	0.983 (4)	0.027*
H2B	0.530 (3)	0.8693 (18)	0.946 (4)	0.027*
O11	−0.1618 (3)	0.78079 (10)	0.9079 (2)	0.0133 (3)
O12	−0.4119 (3)	0.68869 (10)	1.08944 (19)	0.0119 (3)
H12	−0.411 (5)	0.6975 (18)	1.186 (2)	0.018*
O13	−0.0986 (3)	0.54439 (9)	1.2563 (2)	0.0117 (3)
O14	0.0906 (2)	0.67923 (9)	0.98560 (18)	0.0109 (3)
O15	0.2856 (3)	0.47033 (9)	1.13780 (19)	0.0114 (3)
H15	0.381 (4)	0.4895 (18)	1.212 (3)	0.017*
O16	−0.1178 (3)	0.45095 (11)	0.9253 (2)	0.0146 (3)
H16	−0.242 (3)	0.4591 (19)	0.871 (3)	0.022*
C14	−0.1049 (3)	0.71517 (13)	0.9845 (3)	0.0090 (4)
C15	−0.2095 (3)	0.66672 (13)	1.0807 (2)	0.0094 (4)
C16	−0.0767 (3)	0.60100 (13)	1.1513 (2)	0.0094 (4)
C17	0.1305 (3)	0.60872 (12)	1.0993 (3)	0.0095 (4)
H17	0.2499	0.6238	1.1995	0.011*
C18	0.2082 (4)	0.53544 (13)	1.0153 (3)	0.0102 (4)
H18	0.3302	0.5542	0.9773	0.012*
C19	0.0354 (4)	0.49712 (14)	0.8664 (3)	0.0134 (4)
H19A	−0.0401	0.5406	0.7905	0.016*
H19B	0.1045	0.4606	0.8054	0.016*
O21	0.4790 (2)	0.49852 (11)	0.70847 (19)	0.0145 (3)
O22	0.6075 (3)	0.53606 (10)	0.4076 (2)	0.0123 (3)
H22	0.704 (4)	0.5523 (18)	0.377 (4)	0.018*
O23	0.5624 (3)	0.72781 (10)	0.3809 (2)	0.0124 (3)
O24	0.4032 (3)	0.63437 (9)	0.71404 (18)	0.0128 (3)
O25	0.0576 (3)	0.74240 (10)	0.6550 (2)	0.0130 (3)
H25	0.093 (5)	0.7074 (15)	0.723 (3)	0.020*
O26	0.1785 (3)	0.87959 (11)	0.52356 (19)	0.0144 (3)
H26	0.296 (3)	0.891 (2)	0.521 (3)	0.022*
C24	0.4774 (4)	0.56818 (15)	0.6452 (3)	0.0106 (4)
C25	0.5420 (4)	0.59363 (14)	0.5032 (3)	0.0094 (4)
C26	0.5169 (4)	0.67820 (14)	0.4846 (3)	0.0097 (4)
C27	0.4051 (4)	0.70724 (13)	0.6114 (3)	0.0098 (4)
H27	0.4840	0.7535	0.6794	0.012*
C28	0.1622 (4)	0.72909 (13)	0.5272 (3)	0.0110 (4)
H28	0.0912	0.6822	0.4570	0.013*
C29	0.1212 (4)	0.80711 (14)	0.4207 (3)	0.0135 (4)
H29A	0.2067	0.8052	0.3432	0.016*
H29B	−0.0316	0.8098	0.3555	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.01028 (8)	0.00692 (7)	0.01035 (7)	−0.00003 (9)	0.00486 (5)	−0.00059 (9)
O1	0.0248 (8)	0.0091 (9)	0.0153 (7)	−0.0008 (7)	0.0022 (6)	−0.0014 (6)
O2	0.0113 (8)	0.0183 (8)	0.0243 (9)	0.0027 (7)	0.0060 (7)	0.0035 (7)
O11	0.0161 (8)	0.0099 (7)	0.0156 (7)	0.0030 (6)	0.0075 (6)	0.0035 (6)
O12	0.0107 (7)	0.0156 (7)	0.0109 (7)	0.0025 (6)	0.0056 (6)	0.0002 (6)
O13	0.0166 (8)	0.0079 (7)	0.0142 (7)	0.0007 (6)	0.0098 (6)	0.0021 (6)
O14	0.0118 (7)	0.0089 (7)	0.0142 (7)	0.0011 (6)	0.0072 (6)	0.0042 (6)
O15	0.0118 (7)	0.0090 (7)	0.0119 (7)	0.0002 (6)	0.0017 (6)	0.0011 (6)
O16	0.0108 (7)	0.0184 (8)	0.0134 (7)	−0.0035 (6)	0.0016 (6)	0.0033 (6)
C14	0.0098 (9)	0.0083 (9)	0.0096 (9)	−0.0018 (8)	0.0040 (7)	−0.0013 (7)
C15	0.0096 (9)	0.0105 (9)	0.0096 (9)	−0.0003 (7)	0.0051 (7)	−0.0001 (7)
C16	0.0122 (9)	0.0078 (9)	0.0086 (9)	−0.0013 (8)	0.0039 (7)	−0.0014 (7)
C17	0.0110 (9)	0.0060 (9)	0.0117 (9)	0.0003 (7)	0.0036 (7)	0.0027 (7)
C18	0.0124 (10)	0.0093 (9)	0.0100 (9)	0.0018 (8)	0.0051 (8)	0.0003 (7)
C19	0.0153 (10)	0.0156 (10)	0.0109 (10)	−0.0027 (9)	0.0063 (8)	0.0004 (8)
O21	0.0170 (8)	0.0133 (8)	0.0139 (8)	0.0010 (6)	0.0056 (6)	0.0030 (6)
O22	0.0158 (8)	0.0088 (7)	0.0167 (8)	−0.0003 (6)	0.0114 (6)	−0.0028 (6)
O23	0.0166 (9)	0.0110 (8)	0.0118 (7)	−0.0020 (6)	0.0076 (6)	−0.0008 (6)
O24	0.0190 (8)	0.0107 (7)	0.0104 (7)	0.0018 (6)	0.0072 (6)	0.0014 (5)
O25	0.0190 (8)	0.0099 (7)	0.0145 (8)	0.0008 (6)	0.0116 (7)	0.0007 (6)
O26	0.0189 (7)	0.0089 (8)	0.0187 (7)	−0.0028 (7)	0.0107 (6)	−0.0022 (6)
C24	0.0093 (10)	0.0116 (10)	0.0101 (10)	−0.0010 (8)	0.0018 (8)	−0.0011 (8)
C25	0.0084 (10)	0.0100 (10)	0.0109 (9)	0.0009 (8)	0.0047 (8)	0.0018 (8)
C26	0.0074 (10)	0.0124 (10)	0.0100 (9)	−0.0004 (8)	0.0035 (8)	−0.0039 (7)
C27	0.0137 (10)	0.0070 (9)	0.0101 (9)	−0.0007 (8)	0.0057 (8)	0.0002 (8)
C28	0.0136 (10)	0.0112 (9)	0.0099 (9)	−0.0008 (8)	0.0060 (8)	−0.0016 (7)
C29	0.0159 (10)	0.0143 (10)	0.0111 (9)	0.0033 (8)	0.0054 (8)	0.0001 (8)

Geometric parameters (Å, º)

Sr1—O11	2.5446 (16)	C17—C18	1.533 (3)
Sr1—O13^i	2.5688 (15)	C17—H17	0.9800
Sr1—O16^i	2.5699 (16)	C18—C19	1.525 (3)
Sr1—O2	2.5790 (17)	C18—H18	0.9800
Sr1—O1	2.6016 (16)	C19—H19A	0.9700
Sr1—O26	2.6138 (15)	C19—H19B	0.9700
Sr1—O25	2.6215 (16)	O21—C24	1.239 (3)
Sr1—O15^i	2.6423 (16)	O22—C25	1.372 (3)
O1—H1A	0.829 (18)	O22—H22	0.782 (17)
O1—H1B	0.797 (17)	O23—C26	1.277 (3)
O2—H2A	0.820 (17)	O24—C24	1.365 (3)
O2—H2B	0.804 (17)	O24—C27	1.456 (3)
O11—C14	1.232 (3)	O25—C28	1.442 (3)
O12—C15	1.373 (3)	O25—H25	0.783 (17)
O12—H12	0.821 (17)	O26—C29	1.430 (3)
O13—C16	1.302 (2)	O26—H26	0.785 (17)
O14—C14	1.383 (3)	C24—C25	1.432 (3)
O14—C17	1.453 (2)	C25—C26	1.375 (3)
O15—C18	1.445 (2)	C26—C27	1.525 (3)
O15—H15	0.791 (17)	C27—C28	1.547 (3)
O16—C19	1.437 (3)	C27—H27	0.9800
O16—H16	0.802 (18)	C28—C29	1.516 (3)
C14—C15	1.427 (3)	C28—H28	0.9800
C15—C16	1.376 (3)	C29—H29A	0.9700
C16—C17	1.528 (3)	C29—H29B	0.9700
H1A—O1—H1B	110 (3)	H19A—C19—H19B	108.2
H2A—O2—H2B	101 (3)	C25—O22—H22	112 (2)
C15—O12—H12	112 (2)	C24—O24—C27	108.30 (16)
C14—O14—C17	108.08 (15)	C28—O25—H25	109 (2)
C18—O15—H15	107 (2)	C29—O26—H26	105 (3)
C19—O16—H16	113 (2)	O21—C24—O24	119.0 (2)
O11—C14—O14	119.23 (18)	O21—C24—C25	130.3 (2)
O11—C14—C15	130.2 (2)	O24—C24—C25	110.7 (2)
O14—C14—C15	110.58 (17)	O22—C25—C26	130.5 (2)
O12—C15—C16	130.59 (19)	O22—C25—C24	120.5 (2)
O12—C15—C14	120.43 (18)	C26—C25—C24	108.9 (2)
C16—C15—C14	108.97 (19)	O23—C26—C25	130.8 (2)
O13—C16—C15	130.36 (19)	O23—C26—C27	122.3 (2)
O13—C16—C17	122.10 (18)	C25—C26—C27	106.82 (19)
C15—C16—C17	107.27 (17)	O24—C27—C26	104.65 (17)
O14—C17—C16	104.74 (16)	O24—C27—C28	105.29 (17)
O14—C17—C18	108.56 (15)	C26—C27—C28	112.24 (18)
C16—C17—C18	120.17 (17)	O24—C27—H27	111.4
O14—C17—H17	107.6	C26—C27—H27	111.4
C16—C17—H17	107.6	C28—C27—H27	111.4
C18—C17—H17	107.6	O25—C28—C29	105.96 (17)
O15—C18—C19	107.10 (17)	O25—C28—C27	109.34 (17)
O15—C18—C17	108.88 (16)	C29—C28—C27	115.30 (18)
C19—C18—C17	115.30 (18)	O25—C28—H28	108.7
O15—C18—H18	108.5	C29—C28—H28	108.7
C19—C18—H18	108.5	C27—C28—H28	108.7
C17—C18—H18	108.5	O26—C29—C28	110.87 (17)
O16—C19—C18	109.59 (17)	O26—C29—H29A	109.5
O16—C19—H19A	109.8	C28—C29—H29A	109.5
C18—C19—H19A	109.8	O26—C29—H29B	109.5
O16—C19—H19B	109.8	C28—C29—H29B	109.5
C18—C19—H19B	109.8	H29A—C29—H29B	108.1

Symmetry code: (i) −x, y+1/2, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O23^ii	0.83 (2)	1.88 (2)	2.708 (2)	177 (3)
O1—H1B···O21^iii	0.80 (2)	1.96 (2)	2.736 (2)	163 (3)
O2—H2A···O12^iv	0.82 (2)	2.10 (2)	2.920 (2)	175 (3)
O2—H2B···O15^v	0.80 (2)	2.25 (2)	2.971 (2)	150 (3)
O12—H12···O23^vi	0.82 (2)	1.76 (2)	2.571 (2)	172 (3)
O15—H15···O22^vii	0.79 (2)	1.98 (2)	2.768 (2)	177 (3)
O16—H16···O21^ii	0.80 (2)	2.00 (2)	2.783 (2)	167 (3)
O22—H22···O13^viii	0.78 (2)	1.86 (2)	2.579 (2)	154 (3)
O25—H25···O14	0.78 (2)	2.25 (2)	2.893 (2)	140 (3)
O26—H26···O1^iv	0.79 (2)	2.35 (2)	3.100 (2)	161 (4)

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

(IV) Poly[aqua-µ-2-oxidobenzoato-strontium(II)]

Crystal data

[Sr(C7H4O3)(H2O)]	F(000) = 472
Mr = 241.74	Dx = 2.101 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4077 reflections
a = 5.0993 (4) Å	θ = 3.2–30.4°
b = 22.808 (2) Å	µ = 7.02 mm^−1
c = 6.9811 (6) Å	T = 120 K
β = 109.755 (2)°	Irregular, colorless
V = 764.15 (11) Å^3	0.14 × 0.10 × 0.02 mm
Z = 4

Data collection

Bruker SMART APEX diffractometer	2251 independent reflections
Radiation source: fine-focus sealed tube	1917 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ω scan, frame data integration	θmax = 30.9°, θmin = 3.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −7→7
Tmin = 0.440, Tmax = 0.872	k = −32→32
10002 measured reflections	l = −9→10

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: difference Fourier map
wR(F^2) = 0.092	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0573P)^2 + 0.1094P] where P = (Fo^2 + 2Fc^2)/3
2251 reflections	(Δ/σ)max < 0.001
115 parameters	Δρmax = 1.87 e Å^−3
2 restraints	Δρmin = −1.00 e Å^−3

Special details

Experimental. Oxford Cryosystem liquid nitrogen cryostream cooler

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 > 2σ(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
Sr1	0.21082 (5)	0.023582 (11)	0.79827 (4)	0.00859 (10)
O1	0.1711 (4)	0.04870 (9)	0.4455 (3)	0.0124 (4)
O2	0.2722 (4)	0.01515 (9)	0.1812 (3)	0.0116 (4)
O3	0.6267 (4)	0.07957 (8)	0.0468 (3)	0.0110 (4)
C1	0.4460 (6)	0.11029 (12)	0.3122 (4)	0.0101 (5)
C2	0.6007 (6)	0.11929 (12)	0.1780 (4)	0.0103 (5)
C3	0.7369 (6)	0.17410 (13)	0.1914 (5)	0.0156 (6)
H3	0.8377	0.1814	0.1050	0.019*
C4	0.7254 (7)	0.21696 (14)	0.3274 (5)	0.0192 (7)
H4	0.8188	0.2522	0.3320	0.023*
C5	0.5744 (7)	0.20779 (13)	0.4587 (5)	0.0162 (6)
H5	0.5679	0.2365	0.5517	0.019*
C6	0.4350 (6)	0.15527 (13)	0.4476 (5)	0.0134 (6)
H6	0.3304	0.1494	0.5323	0.016*
C7	0.2914 (6)	0.05545 (13)	0.3132 (4)	0.0107 (5)
O4	−0.0506 (5)	0.11408 (9)	0.8271 (4)	0.0169 (4)
H4A	−0.148 (7)	0.1349 (16)	0.734 (5)	0.025*
H4B	−0.164 (7)	0.1041 (17)	0.881 (6)	0.025*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.00914 (15)	0.01337 (15)	0.00278 (14)	−0.00060 (9)	0.00138 (10)	0.00005 (8)
O1	0.0150 (10)	0.0183 (10)	0.0049 (9)	−0.0021 (8)	0.0048 (8)	0.0000 (8)
O2	0.0127 (10)	0.0143 (10)	0.0070 (10)	−0.0019 (7)	0.0024 (8)	−0.0025 (7)
O3	0.0114 (10)	0.0141 (9)	0.0080 (10)	−0.0013 (7)	0.0040 (8)	−0.0015 (7)
C1	0.0100 (12)	0.0135 (12)	0.0061 (12)	−0.0003 (10)	0.0017 (10)	−0.0003 (10)
C2	0.0106 (12)	0.0131 (12)	0.0063 (12)	0.0009 (10)	0.0017 (10)	0.0007 (10)
C3	0.0159 (14)	0.0154 (14)	0.0189 (16)	−0.0031 (11)	0.0102 (13)	−0.0013 (11)
C4	0.0229 (16)	0.0149 (14)	0.0189 (16)	−0.0032 (11)	0.0059 (14)	−0.0023 (12)
C5	0.0177 (15)	0.0154 (14)	0.0142 (15)	0.0030 (11)	0.0039 (12)	−0.0029 (11)
C6	0.0140 (13)	0.0177 (14)	0.0093 (13)	0.0011 (10)	0.0049 (11)	−0.0022 (10)
C7	0.0091 (12)	0.0162 (13)	0.0055 (13)	0.0015 (10)	0.0007 (10)	0.0033 (9)
O4	0.0174 (11)	0.0196 (11)	0.0153 (11)	0.0018 (9)	0.0077 (9)	0.0041 (9)

Geometric parameters (Å, º)

Sr1—O1	2.469 (2)	C1—C2	1.429 (4)
Sr1—O4	2.502 (2)	C1—C7	1.480 (4)
Sr1—O3^i	2.579 (2)	C2—C3	1.418 (4)
Sr1—O2^i	2.591 (2)	C3—C4	1.378 (4)
Sr1—O3^ii	2.605 (2)	C3—H3	0.9300
Sr1—O2^iii	2.666 (2)	C4—C5	1.398 (4)
Sr1—O1^iii	2.677 (2)	C4—H4	0.9300
Sr1—O2^ii	2.738 (2)	C5—C6	1.382 (4)
O1—C7	1.279 (3)	C5—H5	0.9300
O2—C7	1.282 (3)	C6—H6	0.9300
O3—C2	1.326 (3)	O4—H4A	0.821 (19)
C1—C6	1.409 (4)	O4—H4B	0.823 (18)
C6—C1—C2	119.4 (3)	C5—C4—H4	119.8
C6—C1—C7	118.0 (2)	C6—C5—C4	118.7 (3)
C2—C1—C7	122.5 (2)	C6—C5—H5	120.7
O3—C2—C3	119.1 (2)	C4—C5—H5	120.7
O3—C2—C1	124.1 (2)	C5—C6—C1	122.2 (3)
C3—C2—C1	116.7 (3)	C5—C6—H6	118.9
C4—C3—C2	122.5 (3)	C1—C6—H6	118.9
C4—C3—H3	118.8	O1—C7—O2	119.6 (3)
C2—C3—H3	118.8	O1—C7—C1	119.4 (3)
C3—C4—C5	120.5 (3)	O2—C7—C1	120.9 (2)
C3—C4—H4	119.8	H4A—O4—H4B	101 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4B···O3^iv	0.82 (2)	1.90 (2)	2.718 (3)	170 (4)

Symmetry code: (iv) x−1, y, z+1.