Synthesis, crystal structure, and thermal properties of poly[aqua-(μ5-2,5-di-carb-oxy-benzene-1,4-di-carboxyl-ato)strontium].

A coordination polymer formulated as [Sr(H2BTEC)(H2O)] n (H4BTEC = benzene-1,2,4,5-tetra-carb-oxy-lic acid, C10H6O8), was synthesized hydro-thermally and characterized by single-crystal and powder X-ray diffraction, scanning electron microscopy and thermal analysis. Its crystal structure is made up of a zigzag inorganic chain formed by edge-sharing of [SrO8] polyhedra running along [001]. Adjacent chains are connected to each other via the carboxyl-ate groups of the ligand, resulting in a double-layered network extending parallel to (100). O-H⋯O hydrogen bonds of medium-to-weak strength between the layers consolidate the three-dimensional structure. One of the carb-oxy-lic OH functions was found to be disordered over two sets of sites with half-occupancy. © Mokhtari et al. 2020.

Chemical context

In recent years, the self-assembly of coordination pan class="Chemical">polymers (CP) and crystal engineering of pan class="Chemical">metal–organic coordination frameworks have attracted great inter­est because of their varied mol­ecular topologies and the potential applications of these polymers as functional materials (Pan et al., 2004 ▸; Jiang et al., 2011 ▸; Du et al., 2014 ▸). Derivatives of aromatic tetra­carb­oxy­lic acids such as 1,2,4,5-benzene­tetra­carb­oxy­lic acid (H4BTEC, commonly known as pyromellitic acid) and their deprotonated forms (HBTEC(4–) belong to an important family of polycarboxyl­ate O-donor ligands, which have been used extensively to prepare CPs (Liu et al., 2009 ▸). The variations in the possible binding modes of its four potentially coordinating carb­oxy­lic/carboxyl­ate groups, along with the different coordination preferences of the metal ions, gives rise to a great variety of crystal structures.

In this communication, we report on the synthesis of [Sr(pan class="CellLine">H2BTEC)(ne">pan class="Chemical">H2O)], (I), along with its characterization by single-crystal and powder X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray fluorescence, and thermal analysis.

Structural commentary

The asymmetric unit of compound (I) comprises one pan class="Chemical">SrII atom, one doubly deprotonated (ne">pan class="CellLine">H2BTEC)2– anion and one coordinating water mol­ecule O1W (Fig. 1 ▸). The SrII atom is bonded to eight oxygen atoms, seven of them coming from five carboxyl­ate or carb­oxy­lic groups of five different (H2BTEC)2– ligands, and one oxygen atom from the water mol­ecule. The resulting coordination polyhedron around the alkaline earth cation may be described as a distorted bicapped prism (Fig. 2 ▸ a). The Sr—O bond lengths span the range 2.4915 (19)–2.8239 (19) Å for carboxyl­ate/carb­oxy­lic acid groups, and the Sr—O(water) bond length is 2.520 (3) Å. These distances are comparable to those reported in other strontium–carboxyl­ate complexes (He et al., 2014 ▸). The (H2BTEC)2– anion has a bridging character and connects five SrII atoms (Fig. 2 ▸ b) whereby three different coordination modes are realized. The carboxyl­ate group (O1—C1—O2) adopts both a bis-monodentate bridging mode to two SrII atoms and a bidentate chelating mode to a third SrII atom; the carb­oxy­lic group (O7/C10/O8/H8) is monodentately bound through O7 to a fourth SrII atom and shows an intra­molecular O8—H8⋯O6 hydrogen bond (Table 1 ▸); the carboxyl­ate group (O5/C9/O6) exhibits a bidentate chelating mode to a fifth SrII atom. The carb­oxy­lic group (O3/C8/O4/H4) has a disordered hydroxyl group and does not bind to a cation. The [SrO8] polyhedra share edges through (O1—O2), thus forming an infinite zigzag chain running parallel to [001] (Fig. 3 ▸ a). These chains are further connected through the carboxyl­ate groups (O1/C1/O2 and O5/C9/O6) into double layers parallel to (100) that are stacked along [100] (Fig. 3 ▸ b). A topological analysis (Blatov et al., 2014 ▸) revealed that the overall structure of the coordination polymer (I) can be defined as a uninodal five-connected net with the Schläfli symbol {48.62}, and the vertex symbols of SrII and (H2BTEC)2– node is [4.4.4.4.4.4.4.4.6(3).6(3)] (Fig. 4 ▸).

Figure 1

The asymmetric unit of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. (Hy­droxy atom O4 is disordered with a 0.5:0.5 ratio.)

Figure 2

(a) Perspective view of the coordination environment of SrII and (b) coordination modes of the (H2BTEC)2– anion in (I). [Symmetry codes: (i) x, −y + 2, z − ; (ii) x, −y + 1, z − ; (iv) −x + , −y + , −z + 2; (v) x, y, z + 1; (vi) x, −y + 1, z + ; (vii) x, −y + 2, z + .]

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W⋯O3i	0.83	2.25	3.0666 (3)	170
O1W—H2W⋯O3ii	0.83	2.04	2.864 (4)	171
O4A—H4A⋯O5iii	0.82	1.92	2.68 (2)	152
O4B—H4B⋯O5iii	0.82	1.89	2.696 (16)	166
O8—H8⋯O6	0.82	1.59	2.400 (3)	169
C6—H6⋯O4A iii	0.93	2.32	3.240 (18)	169
C6—H6⋯O4B iii	0.93	2.39	3.298 (14)	166

Symmetry codes: (i) ; (ii) ; (iii) .

Figure 3

(a) View of the inorganic chain and (b) the two-dimensional layer structure in the crystal structure of (I).

Figure 4

The uninodal five-connected net for (I).

Supra­molecular features

In the crystal structure of (I), neighbouring layers are linked to each other along the stacking direction by inter­molecular O—H⋯O pan class="Chemical">hydrogen bonds of medium-to-weak strength involving the coordinating pan class="Chemical">water mol­ecule with the carbonyl O atom (O3) of the non-coordinating carb­oxy­lic acid group as acceptor, as well as the pan class="Disease">disordered O4—H4 function of this carb­oxy­lic acid group and carboxyl­ate O atom O4 as an acceptor group (Table 1 ▸). The hydrogen-bonding scheme is completed by two weak inter­molecular C—H⋯O inter­actions involving aromatic H atoms (Table 1 ▸). Based on the connectivity of these hydrogen bonds, four different motifs (Etter et al., 1990 ▸) can be distinguished, viz. (8), (10), (13) and (15) (Fig. 5 ▸), leading to a three-dimensional supra­molecular structure (Figs. 6 ▸, 7 ▸).

Figure 5

The hydrogen-bonded-ring patterns found in (I).

Figure 6

View of the double-layered network along the a axis.

Figure 7

Projection of the three-dimensional structure along [001] axis with hydrogen-bonding inter­actions shown as dashed lines.

Crystal morophology and characterization

SEM images show the appearance of the microcrystalline powder, while EDX measurements provided qualitative confirmation about the presence of all non-pan class="Chemical">hydrogen atoms (Fig. 8 ▸). The FT–IR spectrum of complex (I) (Fig. S1 in the supporting information) shows broad absorption bands near 3440 cm−1, which are assigned to O—H stretching vibrations of the –pan class="Chemical">COOH groups and pan class="Chemical">water mol­ecules, respectively. The bands located at 3164 cm−1 can be attributed to aromatic C—H stretching vibration. In addition, the symmetric [νs(OCO) = 1414 and 1346 cm−1] and asymmetric [νas(OCO) = 1626 and 1533 cm−1] stretching vibrations in (I) can be attributed to the split of the absorption bands of the carboxyl­ate groups. The Δ(νas–νs) values of 187–212 cm−1 indicate that some of the carboxyl­ate groups are monodentate and bridging to the SrII atoms. A strong absorption at 1731 cm−1 confirms the presence of the carb­oxy­lic acid function. All these results are in agreement with the crystallographic data.

Figure 8

(a) SEM images and (b) a typical EDX spectrum with a table of the qu­anti­tative analysis results for Sr, O and C (in at%).

Plots of the experimental and simulated powder X-ray diffraction (PXRD) patterns of the title compound are shown in Fig. 9 ▸, revealing a good match and thus phase purity and repeatable synthesis. TG/pan class="Chemical">DTG, pan class="Chemical">SDTA curves and the mass spectrometry analysis are depicted in Fig. 10 ▸ a. TG/DTG curves of (I) reveal a total mass loss of ca 60.5% (calc. 58.1%) from room temperature up to 1273 K, with SrO as the final product. The mass loss of (I), under a dry N2 atmosphere, proceeds in four steps. The first one, between 298 and 550 K with a mass loss of ca 5.2% (cal. 5.0%), is associated with an endothermic reaction (491 K in the SDTA curve) and corres­ponds to the loss of the coordinating water mol­ecule. The second step, between 557 and 719 K with a mass loss of ca 22.1% (calc. 25.7%) and an endothermic reaction (peak at 609 K), is attributed to the beginning of the decomposition of the (H2BTEC)2– ligand. The third step, between 706 and 908 K with a mass loss of about 15.3% is exothermic (peak at 882 K), and may be attributed to the complete decomposition of the organic anion. The fourth step, between 908 and 1147 K with a mass loss of 17.9% is also exothermic (peak at 1121 K), and may be due to another evaporation of trapped organic moieties. The associated mass spectroscopy m/z 18 (H2O), 44 (CO2), and 76 (C6H4) curves (Fig. 10 ▸ b) are in agreement with the TG/DTG data. The m/z 18 curve has four maxima, the first and second maxima at 565 and 639 K correspond to the loss of the coordinating water mol­ecules. The third maximum at 682 K coincides with the m/z 44 and 76 curves, which is attributed to the first decomposition step of the organic anion, and the last maximum at 806 K coincides with the second maximum of m/z 44 and 76.

Figure 9

Powder XRD patterns of (I) compared with the calculated one.

Figure 10

(a) TG–DTG–SDTA curves and (b) m/z 18 (H2O), m/z 44 (CO2) and m/z 76 (C6H4) MS signals for (I).

Database survey

A search of the Cambridge Structural Database (CSD, version 5.40, update November 2018; Groom et al., 2016 ▸) resulted in 196 hits for the (pan class="Chemical">H4BTEC)2– dianion. To the best of our knowledge, there are only two alkaline earth coordination pan class="Chemical">polymers made up from the (H2BTEC)2– dianion, viz. Ba(H2BTEC)(H2O)5] (Dale et al., 2003 ▸) and [Sr2(H2BTEC)2(H2O)2] (Balegroune et al., 2011 ▸). In the Ba compound, the alkaline earth cation displays a monocapped square-anti­prismatic coordination environment, and the coordination mode of the (H2BTEC)2– ligand is monodentate to four cations at a time. The Sr compound is based on [SrO8] and [SrO9] polyhedra sharing edges, with the two independent (H2BTEC)2– ligands coordinating to five- and six-metal cations, respectively. Compound (I) with its layered structure has a different set-up and is not comparable with these two previously reported structures.

Synthesis and crystallization

6.1. Synthesis

Chemicals were purchased from commercial sources and used without any further purification. Compound (I) was synthesized under hydro­thermal conditions. 0.26 g (1 mmol) of pan class="Chemical">SrCl2,ne">pan class="Chemical">6H2O, 0.25 g (1 mmol) of pyromellitic acid (H4BTEC) and 0.04 g (1 mmol) of NaOH were dissolved in water (13 ml). The reaction mixture was stirred at room temperature to homogeneity and then placed in a Teflon-lined stainless vessel (40 ml) and heated to 433 K for 3 d under autogenous pressure, and afterwards cooled to room temperature. The resulting product of plate-like single crystals and microcrystalline powder was filtered off, washed thoroughly with distilled water, and finally air-dried at room temperature.

6.2. Experimental details

Powder X-ray diffraction patterns were recorded on a Philips X’pert diffractometer with Cu Kα radiation. The samples were gently ground in an agate mortar in order to minimize the preferred orientation. All data were collected at room temperature over the 2θ angular range of 4–60° with a step of 0.01° and a counting time of 1.5 s per step. IR spectra were recorded with a JASCO FTIR-6300 spectrometer in the region 4000–600 cm−1. SEM micrographs and X-ray microanalysis (SEM/EDX) were recorded by using a JEOL-6610LV scanning electron microscope operating at 30 kV coupled with an Oxford X-Max microanalysis system (EDX). A Mettler–Toledo TGA/pan class="Chemical">SDTA851e was used for the thermal analysis in a nitro­gen dynamic atmosphere (50 ml min−1) at a heating rate of 10 K min−1. In this case, ca 10 mg of a powder sample were thermally treated, and blank runs were performed with the empty crucible.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. C-bound pan class="Chemical">hydrogen atoms were placed in idealized positions and refined with C—H = 0.93 Å and U iso = 1.2U eq(C). The pan class="Chemical">hydrogen atoms of the pan class="Chemical">water mol­ecule and of the carb­oxy­lic groups were located in a difference-Fourier map and were refined with O—H = 0.93 and 0.92 Å, respectively, and with U iso(H) = 1.5U eq(O). One of the carb­oxy­lic OH functions (O4—H4) was found to be disordered over two sets of sites of equal occupancy.

Table 2

Experimental details

Crystal data
Chemical formula	[Sr(C10H4O8)(H2O)]
M r	357.77
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	295
a, b, c (Å)	25.8191 (7), 11.9726 (3), 7.1467 (2)
β (°)	90.662 (2)
V (Å3)	2209.05 (10)
Z	8
Radiation type	Mo Kα
μ (mm−1)	4.93
Crystal size (mm)	0.23 × 0.14 × 0.10
Data collection
Diffractometer	Oxford Diffraction Xcalibur, Ruby, Gemini
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2015 ▸)
T min, T max	0.833, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	16106, 3417, 2700
R int	0.045
(sin θ/λ)max (Å−1)	0.734
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.043, 0.086, 1.08
No. of reflections	3417
No. of parameters	199
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.70, −0.41

Computer programs: CrysAlis CCD (Oxford Diffraction, 2015 ▸), CrysAlis RED (Oxford Diffraction, 2015 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL97 (Sheldrick, 2008 ▸), ORTEP-3 for Windows and WinGX (Farrugia, 2012 ▸) and DIAMOND (Brandenburg & Berndt, 2001 ▸).

Crystal structure: contains datablock(s) SM112, I. DOI: 10.1107/S2056989020002005/wm5542sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989020002005/wm5542Isup2.hkl

Click here for additional data file.

Figure S1. DOI: 10.1107/S2056989020002005/wm5542sup3.tif

CCDC reference: 1890785

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Sr(C10H4O8)(H2O)]	F(000) = 1408
Mr = 357.77	Dx = 2.151 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 5087 reflections
a = 25.8191 (7) Å	θ = 2.9–30.9°
b = 11.9726 (3) Å	µ = 4.93 mm−1
c = 7.1467 (2) Å	T = 295 K
β = 90.662 (2)°	Prism, colorless
V = 2209.05 (10) Å3	0.23 × 0.14 × 0.10 mm
Z = 8

Oxford Diffraction Xcalibur, Ruby, Gemini diffractometer	3417 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2700 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.045
Detector resolution: 10.2673 pixels mm-1	θmax = 31.5°, θmin = 2.9°
CCD rotation images, thick slices scans	h = −36→37
Absorption correction: multi-scan (CrysAlis Pro; Oxford Diffraction, 2015)	k = −17→16
Tmin = 0.833, Tmax = 1.000	l = −9→10
16106 measured reflections

Refinement on F2	0 constraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.043	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.086	w = 1/[σ2(Fo2) + (0.0329P)2 + 3.281P] where P = (Fo2 + 2Fc2)/3
S = 1.08	(Δ/σ)max = 0.007
3417 reflections	Δρmax = 0.70 e Å−3
199 parameters	Δρmin = −0.41 e Å−3
2 restraints

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.86646 (10)	0.8405 (2)	0.6041 (4)	0.0220 (5)
C2	0.86705 (10)	0.7142 (2)	0.6075 (3)	0.0212 (5)
C3	0.82120 (11)	0.6600 (2)	0.6499 (4)	0.0245 (6)
H3	0.7921	0.703	0.6754	0.029*
C4	0.81681 (10)	0.5436 (2)	0.6561 (4)	0.0222 (5)
C5	0.86102 (10)	0.4787 (2)	0.6146 (3)	0.0206 (5)
C6	0.90708 (11)	0.5344 (2)	0.5760 (4)	0.0252 (6)
H6	0.9366	0.4923	0.5527	0.03*
C7	0.91076 (11)	0.6508 (2)	0.5708 (4)	0.0240 (6)
C8	0.96109 (11)	0.7054 (2)	0.5286 (4)	0.0310 (6)
C9	0.86422 (11)	0.3525 (2)	0.6049 (4)	0.0253 (6)
C10	0.76333 (11)	0.5051 (2)	0.7169 (4)	0.0290 (6)
O1	0.86950 (8)	0.89053 (15)	0.7574 (3)	0.0306 (5)
O2	0.86043 (9)	0.88916 (15)	0.4518 (3)	0.0346 (5)
O1W	0.95292 (11)	0.9470 (2)	1.1096 (5)	0.0641 (8)
H2W	0.9779 (14)	0.908 (4)	1.077 (7)	0.096*
H1W	0.959 (2)	1.012 (2)	1.076 (7)	0.096*
O3	0.96836 (9)	0.80320 (18)	0.5342 (5)	0.0607 (8)
O4A	1.0004 (6)	0.6356 (8)	0.533 (7)	0.049 (6)	0.50 (7)
H4A	1.0275	0.6705	0.5217	0.073*	0.50 (7)
O4B	0.9931 (6)	0.6371 (9)	0.438 (6)	0.044 (4)	0.50 (7)
H4B	1.022	0.6653	0.4338	0.066*	0.50 (7)
O5	0.90652 (8)	0.30446 (16)	0.5932 (3)	0.0361 (5)
O6	0.82258 (8)	0.29547 (16)	0.6041 (3)	0.0393 (5)
O7	0.73445 (9)	0.57112 (19)	0.7873 (4)	0.0531 (7)
O8	0.74913 (10)	0.40310 (19)	0.7001 (5)	0.0699 (10)
H8	0.7727	0.3666	0.6541	0.105*
Sr	0.85719 (2)	0.90596 (2)	1.10167 (3)	0.02469 (9)

	U11	U22	U33	U12	U13	U23
C1	0.0257 (14)	0.0109 (11)	0.0295 (13)	0.0010 (9)	0.0059 (11)	0.0014 (10)
C2	0.0295 (14)	0.0118 (11)	0.0222 (12)	0.0040 (10)	−0.0010 (11)	0.0013 (10)
C3	0.0274 (14)	0.0143 (12)	0.0318 (14)	0.0049 (10)	0.0014 (11)	0.0000 (11)
C4	0.0276 (14)	0.0143 (12)	0.0247 (13)	0.0012 (10)	0.0004 (11)	0.0000 (10)
C5	0.0283 (13)	0.0089 (10)	0.0247 (12)	0.0030 (10)	0.0017 (10)	−0.0009 (10)
C6	0.0272 (14)	0.0132 (12)	0.0352 (15)	0.0028 (10)	0.0025 (11)	0.0009 (11)
C7	0.0288 (14)	0.0114 (12)	0.0321 (14)	0.0007 (10)	0.0050 (11)	0.0014 (10)
C8	0.0293 (15)	0.0159 (13)	0.0479 (18)	0.0019 (11)	0.0065 (13)	0.0005 (12)
C9	0.0360 (16)	0.0126 (12)	0.0276 (13)	0.0001 (11)	0.0051 (12)	0.0004 (11)
C10	0.0270 (14)	0.0197 (13)	0.0405 (16)	0.0008 (11)	0.0028 (12)	−0.0007 (12)
O1	0.0493 (13)	0.0143 (9)	0.0283 (10)	−0.0005 (8)	0.0061 (9)	−0.0026 (8)
O2	0.0604 (15)	0.0153 (9)	0.0281 (10)	0.0013 (9)	−0.0010 (10)	0.0045 (8)
O1W	0.0398 (15)	0.0346 (14)	0.118 (3)	0.0015 (12)	0.0062 (16)	−0.0016 (17)
O3	0.0397 (13)	0.0185 (11)	0.124 (3)	−0.0074 (10)	0.0248 (14)	−0.0081 (13)
O4A	0.028 (3)	0.016 (2)	0.103 (18)	0.005 (2)	0.017 (6)	0.011 (5)
O4B	0.030 (4)	0.024 (3)	0.079 (12)	0.004 (2)	0.017 (5)	0.004 (4)
O5	0.0336 (11)	0.0132 (9)	0.0617 (14)	0.0025 (8)	0.0069 (10)	−0.0006 (9)
O6	0.0342 (11)	0.0135 (9)	0.0704 (15)	−0.0028 (8)	0.0131 (10)	−0.0022 (10)
O7	0.0299 (12)	0.0283 (12)	0.102 (2)	0.0011 (10)	0.0166 (13)	−0.0157 (13)
O8	0.0455 (15)	0.0218 (12)	0.143 (3)	−0.0086 (10)	0.0482 (17)	−0.0161 (14)
Sr	0.03497 (15)	0.01095 (12)	0.02837 (14)	−0.00125 (10)	0.01032 (10)	−0.00039 (10)

C1—O2	1.243 (3)	C10—O7	1.201 (3)
C1—O1	1.251 (3)	C10—O8	1.280 (3)
C1—C2	1.512 (3)	O1—Sr	2.4915 (19)
C1—Sri	3.045 (3)	O1—Sri	2.6959 (19)
C2—C3	1.386 (4)	O2—Sriii	2.510 (2)
C2—C7	1.388 (4)	O2—Sri	2.6785 (19)
C3—C4	1.400 (4)	O1W—Sr	2.520 (3)
C3—H3	0.93	O1W—H2W	0.830 (19)
C4—C5	1.415 (3)	O1W—H1W	0.826 (19)
C4—C10	1.524 (4)	O4A—H4A	0.82
C5—C6	1.394 (4)	O4B—H4B	0.82
C5—C9	1.516 (4)	O5—Srii	2.8238 (19)
C6—C7	1.397 (3)	O6—Srii	2.572 (2)
C6—H6	0.93	O7—Sriv	2.519 (2)
C7—C8	1.488 (4)	O8—H8	0.82
C8—O3	1.187 (3)	Sr—O2v	2.510 (2)
C8—O4A	1.314 (12)	Sr—O7iv	2.519 (2)
C8—O4B	1.337 (12)	Sr—O6vi	2.572 (2)
C9—O5	1.238 (3)	Sr—O2vii	2.6785 (19)
C9—O6	1.273 (3)	Sr—O1vii	2.6959 (19)
C9—Srii	3.099 (3)	Sr—O5vi	2.8239 (19)
O2—C1—O1	123.3 (2)	C1—O2—Sriii	155.89 (18)
O2—C1—C2	119.0 (2)	C1—O2—Sri	94.78 (16)
O1—C1—C2	117.7 (2)	Sriii—O2—Sri	108.93 (7)
O2—C1—Sri	61.23 (14)	Sr—O1W—H2W	131 (4)
O1—C1—Sri	62.05 (13)	Sr—O1W—H1W	112 (4)
C2—C1—Sri	176.01 (17)	H2W—O1W—H1W	107 (5)
C3—C2—C7	118.9 (2)	C8—O4A—H4A	109.5
C3—C2—C1	117.6 (2)	C8—O4B—H4B	109.5
C7—C2—C1	123.5 (2)	C9—O5—Srii	90.82 (16)
C2—C3—C4	122.9 (2)	C9—O6—Srii	102.06 (16)
C2—C3—H3	118.6	C10—O7—Sriv	142.5 (2)
C4—C3—H3	118.6	C10—O8—H8	109.5
C3—C4—C5	118.3 (2)	O1—Sr—O2v	167.19 (7)
C3—C4—C10	112.6 (2)	O1—Sr—O7iv	116.75 (9)
C5—C4—C10	129.0 (2)	O2v—Sr—O7iv	73.47 (9)
C6—C5—C4	118.1 (2)	O1—Sr—O1W	84.28 (10)
C6—C5—C9	114.9 (2)	O2v—Sr—O1W	88.39 (10)
C4—C5—C9	127.0 (2)	O7iv—Sr—O1W	153.66 (10)
C5—C6—C7	122.7 (2)	O1—Sr—O6vi	89.16 (7)
C5—C6—H6	118.6	O2v—Sr—O6vi	85.74 (7)
C7—C6—H6	118.6	O7iv—Sr—O6vi	76.84 (7)
C2—C7—C6	119.0 (2)	O1W—Sr—O6vi	121.57 (8)
C2—C7—C8	120.8 (2)	O1—Sr—O2vii	70.61 (6)
C6—C7—C8	120.2 (2)	O2v—Sr—O2vii	118.11 (5)
O3—C8—O4A	120.3 (7)	O7iv—Sr—O2vii	93.44 (8)
O3—C8—O4B	121.4 (6)	O1W—Sr—O2vii	78.18 (9)
O3—C8—C7	124.4 (3)	O6vi—Sr—O2vii	150.91 (7)
O4A—C8—C7	113.1 (5)	O1—Sr—O1vii	117.32 (5)
O4B—C8—C7	112.1 (5)	O2v—Sr—O1vii	70.04 (6)
O5—C9—O6	119.8 (2)	O7iv—Sr—O1vii	83.01 (7)
O5—C9—C5	121.0 (2)	O1W—Sr—O1vii	72.76 (8)
O6—C9—C5	119.2 (2)	O6vi—Sr—O1vii	152.13 (7)
O5—C9—Srii	65.65 (14)	O2vii—Sr—O1vii	48.19 (6)
O6—C9—Srii	54.25 (13)	O1—Sr—O5vi	81.37 (6)
C5—C9—Srii	173.12 (18)	O2v—Sr—O5vi	86.56 (7)
O7—C10—O8	119.3 (3)	O7iv—Sr—O5vi	121.96 (7)
O7—C10—C4	119.3 (3)	O1W—Sr—O5vi	74.46 (8)
O8—C10—C4	121.4 (2)	O6vi—Sr—O5vi	47.19 (6)
C1—O1—Sr	153.31 (17)	O2vii—Sr—O5vi	142.39 (6)
C1—O1—Sri	93.76 (15)	O1vii—Sr—O5vi	139.83 (6)
Sr—O1—Sri	108.96 (7)
O2—C1—C2—C3	−96.5 (3)	C6—C7—C8—O4B	22 (2)
O1—C1—C2—C3	79.9 (3)	C6—C5—C9—O5	10.9 (4)
O2—C1—C2—C7	83.5 (3)	C4—C5—C9—O5	−169.8 (3)
O1—C1—C2—C7	−100.0 (3)	C6—C5—C9—O6	−167.3 (2)
C7—C2—C3—C4	−0.5 (4)	C4—C5—C9—O6	12.0 (4)
C1—C2—C3—C4	179.5 (2)	C3—C4—C10—O7	−14.4 (4)
C2—C3—C4—C5	−0.9 (4)	C5—C4—C10—O7	162.8 (3)
C2—C3—C4—C10	176.7 (2)	C3—C4—C10—O8	167.8 (3)
C3—C4—C5—C6	2.1 (4)	C5—C4—C10—O8	−15.0 (5)
C10—C4—C5—C6	−175.0 (3)	O2—C1—O1—Sr	149.6 (3)
C3—C4—C5—C9	−177.2 (2)	C2—C1—O1—Sr	−26.7 (5)
C10—C4—C5—C9	5.8 (5)	Sri—C1—O1—Sr	148.8 (4)
C4—C5—C6—C7	−2.1 (4)	O2—C1—O1—Sri	0.8 (3)
C9—C5—C6—C7	177.3 (3)	C2—C1—O1—Sri	−175.5 (2)
C3—C2—C7—C6	0.6 (4)	O1—C1—O2—Sriii	168.9 (3)
C1—C2—C7—C6	−179.5 (3)	C2—C1—O2—Sriii	−14.9 (6)
C3—C2—C7—C8	−178.7 (3)	Sri—C1—O2—Sriii	169.7 (5)
C1—C2—C7—C8	1.3 (4)	O1—C1—O2—Sri	−0.8 (3)
C5—C6—C7—C2	0.7 (4)	C2—C1—O2—Sri	175.5 (2)
C5—C6—C7—C8	−180.0 (3)	O6—C9—O5—Srii	−3.8 (3)
C2—C7—C8—O3	4.7 (5)	C5—C9—O5—Srii	178.0 (2)
C6—C7—C8—O3	−174.6 (3)	O5—C9—O6—Srii	4.3 (3)
C2—C7—C8—O4A	168 (2)	C5—C9—O6—Srii	−177.48 (19)
C6—C7—C8—O4A	−12 (2)	O8—C10—O7—Sriv	−9.8 (6)
C2—C7—C8—O4B	−159.0 (19)	C4—C10—O7—Sriv	172.4 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···O3vii	0.83	2.25	3.0666 (3)	170
O1W—H2W···O3viii	0.83	2.04	2.864 (4)	171
O4A—H4A···O5ix	0.82	1.92	2.68 (2)	152
O4B—H4B···O5ix	0.82	1.89	2.696 (16)	166
O8—H8···O6	0.82	1.59	2.400 (3)	169
C6—H6···O4Aix	0.93	2.32	3.240 (18)	169
C6—H6···O4Bix	0.93	2.39	3.298 (14)	166