A tetra­nuclear cobalt(III) cluster with 2-(hydroxy­meth­yl)pyridine ligands

Wang, F.-M.; Lu, C.-S.; Li, Y.-Z.; Meng, Q.-J.

doi:10.1107/S1600536810015369

metal-organic compounds

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ISSN: 2056-9890

Volume 66| Part 5| May 2010| Page m594

https://doi.org/10.1107/S1600536810015369

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A tetranuclear cobalt(III) cluster with 2-(hydroxymethyl)pyridine ligands

Fang-Ming Wang,^a ^* Chang-Sheng Lu,^a Yi-Zhi Li ^a and Qing-Jin Meng ^a

^aState Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, People's Republic of China
^*Correspondence e-mail: wangfmzj@yahoo.com.cn

(Received 1 April 2010; accepted 26 April 2010; online 30 April 2010)

In the title compound, tetrakis[μ₃-(2-pyridyl)methanolato]tetrakis[bromido(methanol)cobalt(III)] tetrabromide 2-(hydroxymethyl)pyridine tetrasolvate dihydrate, [Co₄Br₄(C₆H₆NO)₄(CH₃OH)₄]Br₄·4C₆H₇NO₄·2H₂O, the cation comprises a [Co₄O₄] cubane-type core ( $[\overline4]$ symmetry). The four Co^III ions and bridging O atoms from four (2-pyridyl)methanolate anions are located at alternating vertices of the cube, with bromide ions and methanol ligands on the exterior of the core, completing a distorted octahedral geometry. The structure is stablized by intermolecular O—H⋯Br and O—H⋯O interactions.

Related literature

For related structures and magnetic properties, see: Tong et al. (2002 ); Yang et al. (2002 ); Zhao et al. (2004 ).

Experimental

Crystal data

[Co₄Br₄(C₆H₆NO)₄(CH₄O)₄]Br₄·4C₆H₇NO₄·2H₂O
M_r = 1908.10
Tetragonal, $[I \overline 4_2 d ]$
a = 16.5302 (6) Å
c = 29.875 (2) Å
V = 8163.3 (8) Å³
Z = 4
Mo Kα radiation
μ = 4.77 mm⁻¹
T = 291 K
0.30 × 0.24 × 0.22 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.265, T_max = 0.350
21461 measured reflections
4018 independent reflections
3180 reflections with I > 2σ(I)
R_int = 0.056

Refinement

R[F² > 2σ(F²)] = 0.052
wR(F²) = 0.113
S = 0.99
4018 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.75 e Å⁻³
Δρ_min = −0.56 e Å⁻³
Absolute structure: Flack (1983 ), 1822 Friedel pairs
Flack parameter: 0.025 (18)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2B⋯Br1ⁱ	0.97	2.54	3.217 (5)	127
O3—H3A⋯O3ⁱⁱ	0.96	2.31	3.030 (9)	132
O3—H3A⋯O4ⁱⁱⁱ	0.96	2.57	3.370 (11)	141
Symmetry codes: (i) $[y-{\script{1\over 2}}, -x+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[y+{\script{1\over 2}}, -x+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[-y+{\script{3\over 2}}, x-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810015369/bx2274sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810015369/bx2274Isup2.hkl

checkCIF report

Comment top

There have characterized many polynuclear oxide-bridged metal complexes which having a cubane-type structural geometry, because of their relevance to multi-electron transfer centers in biological systems, and to their interesting magnetic and optical properties, as well as to their potential relevance to inorganic solids.

In this work, we synthesized a new tetranuclearCo(III) cluster [Co(hmp)(MeOH)Br]₄Br₄.4Hhmp.2H₂O which comprise a cationic "cubane"-type core (1), where Hhmp is 2-(hydroxymethyl)pyridine. The molecular structure of the cationic cubane core of (1) is shown in Fig. 1. The four cobalt ions and bridging hydroxy group oxygen atoms from four (2-pyridyl)methanolate anions are located at alternating vertices of a cube, with (2-pyridyl)methanolate anion, bromine ion and methanol ligand on the exterior of the core. Furthermore, the three-dimensional supramolecularstructure is stabilized by intramolecular and intermolecular hydrogen bonds. The hydrogen-bonding distances are 3.217 (5) Å (O2–H2B···Br1), 3.030 (9) Å (O3–H3A···O3) and 3.370 (11)Å (O3–H3A···O4), Table 1.

Related literature top

For related structures and magnetic properties, see: Tong et al. (2002); Yang et al. (2002); Zhao et al. (2004).

Experimental top

Compound [Co(hmp)(MeOH)Br]₄Br₄.4Hhmp.2H₂O was synthesized as the process shown in reference (Yang et al., 2002). A mixture of CoBr₂.6H₂O (0.327 g, 1 mmol), Hhmp (0.109 g, 1 mmol), and NaOMe (0.054 g, 1 mmol) in 10 ml of MeOH was refluxed for 30 min. The resulting solution was filtered when it was still hot. Purple crystals suitable for X-ray analysis were obtained from the filtrate after several days.

Structure description top

For related structures and magnetic properties, see: Tong et al. (2002); Yang et al. (2002); Zhao et al. (2004).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. A view of the molecular structure of the cationic cubane core.

tetrakis[µ₃-(2-pyridyl)methanolato]tetrakis[bromido(methanol)cobalt(III)] tetrabromide 2-(hydroxymethyl)pyridine tetrasolvate dihydrate top

Crystal data top

[Co₄Br₄(C₆H₆NO)₄(CH₄O)₄]Br₄·4C₆H₇NO₄·2H₂O	D_x = 1.553 Mg m⁻³
M_r = 1908.10	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4₂d	Cell parameters from 4154 reflections
Hall symbol: I -4 2bw	θ = 2.2–23.1°
a = 16.5302 (6) Å	µ = 4.77 mm⁻¹
c = 29.875 (2) Å	T = 291 K
V = 8163.3 (8) Å³	Block, purple
Z = 4	0.30 × 0.24 × 0.22 mm
F(000) = 3760

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	4018 independent reflections
Radiation source: sealed tube	3180 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.056
phi and ω scans	θ_max = 26.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −15→20
T_min = 0.265, T_max = 0.350	k = −20→17
21461 measured reflections	l = −32→36

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.052	H-atom parameters constrained
wR(F²) = 0.113	w = 1/[σ²(F_o²) + (0.0635P)²] where P = (F_o² + 2F_c²)/3
S = 0.99	(Δ/σ)_max < 0.001
4018 reflections	Δρ_max = 0.75 e Å⁻³
200 parameters	Δρ_min = −0.56 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1822 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.025 (18)

Crystal data top

[Co₄Br₄(C₆H₆NO)₄(CH₄O)₄]Br₄·4C₆H₇NO₄·2H₂O	Z = 4
M_r = 1908.10	Mo Kα radiation
Tetragonal, I4₂d	µ = 4.77 mm⁻¹
a = 16.5302 (6) Å	T = 291 K
c = 29.875 (2) Å	0.30 × 0.24 × 0.22 mm
V = 8163.3 (8) Å³

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	4018 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2000)	3180 reflections with I > 2σ(I)
T_min = 0.265, T_max = 0.350	R_int = 0.056
21461 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	H-atom parameters constrained
wR(F²) = 0.113	Δρ_max = 0.75 e Å⁻³
S = 0.99	Δρ_min = −0.56 e Å⁻³
4018 reflections	Absolute structure: Flack (1983), 1822 Friedel pairs
200 parameters	Absolute structure parameter: 0.025 (18)
0 restraints

Special details top

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.

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)
Br1	−0.05719 (4)	0.72378 (5)	0.20269 (3)	0.04360 (19)
Br2	0.27436 (4)	0.77454 (4)	0.29686 (2)	0.04162 (18)
C1	0.0376 (4)	0.6172 (5)	0.1104 (3)	0.0415 (17)
H1	−0.0035	0.6554	0.1126	0.050*
C2	0.0725 (5)	0.6005 (5)	0.0696 (2)	0.0423 (18)
H2	0.0556	0.6285	0.0443	0.051*
C3	0.1331 (5)	0.5422 (5)	0.0658 (2)	0.0417 (18)
H3	0.1564	0.5311	0.0381	0.050*
C4	0.1584 (5)	0.5003 (5)	0.1042 (3)	0.0453 (18)
H4	0.1974	0.4600	0.1021	0.054*
C5	0.1241 (5)	0.5198 (5)	0.1460 (2)	0.0422 (17)
C6	0.1358 (5)	0.4721 (5)	0.1851 (2)	0.0385 (16)
H6A	0.1356	0.4156	0.1763	0.046*
H6B	0.1891	0.4840	0.1969	0.046*
C7	0.1841 (5)	0.7172 (5)	0.1922 (3)	0.0460 (18)
H7A	0.2247	0.6876	0.1760	0.069*
H7B	0.2096	0.7567	0.2110	0.069*
H7C	0.1488	0.7439	0.1714	0.069*
C8	0.5885 (5)	−0.0934 (5)	0.1084 (2)	0.0432 (18)
H8	0.5728	−0.1472	0.1111	0.052*
C9	0.6092 (5)	−0.0630 (5)	0.0676 (3)	0.0415 (17)
H9	0.6083	−0.0967	0.0426	0.050*
C10	0.6315 (5)	0.0173 (5)	0.0626 (3)	0.0468 (19)
H10	0.6441	0.0378	0.0345	0.056*
C11	0.6350 (4)	0.0673 (5)	0.1005 (3)	0.0454 (19)
H11	0.6512	0.1210	0.0978	0.055*
C12	0.6141 (5)	0.0361 (5)	0.1423 (3)	0.0446 (18)
C13	0.6198 (5)	0.0845 (5)	0.1836 (3)	0.0458 (19)
H13A	0.6736	0.0803	0.1964	0.055*
H13B	0.6085	0.1409	0.1774	0.055*
Co1	0.02308 (6)	0.59361 (6)	0.21302 (3)	0.0396 (2)
N1	0.0641 (4)	0.5764 (3)	0.1481 (2)	0.0367 (14)
N2	0.5908 (4)	−0.0430 (4)	0.1466 (2)	0.0407 (14)
O1	0.0801 (3)	0.4821 (3)	0.21907 (16)	0.0415 (11)
O2	0.1369 (3)	0.6610 (3)	0.21993 (16)	0.0384 (11)
H2B	0.1741	0.6162	0.2238	0.046*
O3	0.5652 (3)	0.0547 (3)	0.21175 (16)	0.0445 (12)
H3A	0.5927	0.0323	0.2372	0.053*
O4	0.5585 (6)	0.7840 (6)	0.2123 (3)	0.044 (2)	0.50
H4A	0.5964	0.7521	0.2297	0.053*	0.50
H4B	0.5115	0.7846	0.2318	0.053*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0435 (4)	0.0479 (4)	0.0394 (4)	0.0080 (3)	0.0066 (3)	0.0131 (3)
Br2	0.0410 (4)	0.0412 (4)	0.0427 (4)	−0.0152 (3)	0.0104 (3)	0.0128 (3)
C1	0.037 (4)	0.046 (4)	0.041 (4)	0.014 (3)	0.018 (3)	0.001 (3)
C2	0.042 (4)	0.050 (4)	0.035 (4)	0.008 (3)	0.010 (3)	0.014 (3)
C3	0.047 (4)	0.042 (4)	0.035 (4)	0.011 (3)	0.020 (3)	0.002 (3)
C4	0.049 (4)	0.043 (4)	0.044 (4)	0.009 (3)	0.012 (4)	0.006 (3)
C5	0.049 (4)	0.041 (4)	0.036 (4)	0.004 (3)	0.008 (3)	0.010 (3)
C6	0.037 (4)	0.041 (4)	0.037 (4)	0.012 (3)	0.013 (3)	0.010 (3)
C7	0.048 (4)	0.039 (4)	0.051 (5)	−0.003 (3)	0.007 (3)	0.010 (4)
C8	0.046 (4)	0.044 (4)	0.040 (4)	0.023 (3)	0.010 (3)	0.015 (3)
C9	0.042 (4)	0.045 (4)	0.038 (4)	0.011 (3)	0.006 (3)	0.018 (3)
C10	0.051 (5)	0.054 (5)	0.035 (4)	−0.009 (4)	−0.011 (3)	0.019 (4)
C11	0.038 (4)	0.049 (5)	0.050 (5)	0.014 (3)	0.013 (3)	0.008 (4)
C12	0.044 (4)	0.044 (4)	0.046 (4)	−0.020 (3)	0.008 (3)	−0.006 (3)
C13	0.054 (5)	0.031 (4)	0.052 (5)	0.007 (3)	0.005 (4)	−0.008 (3)
Co1	0.0400 (5)	0.0405 (5)	0.0384 (6)	0.0002 (4)	0.0028 (4)	0.0029 (4)
N1	0.037 (3)	0.029 (3)	0.044 (3)	−0.009 (2)	0.013 (3)	0.002 (2)
N2	0.040 (3)	0.038 (3)	0.044 (4)	−0.001 (3)	0.012 (3)	0.011 (3)
O1	0.041 (3)	0.042 (3)	0.041 (3)	0.004 (2)	0.018 (2)	0.005 (2)
O2	0.036 (3)	0.044 (3)	0.035 (3)	0.0024 (19)	0.000 (2)	0.010 (2)
O3	0.052 (3)	0.052 (3)	0.029 (3)	−0.012 (2)	−0.014 (2)	−0.008 (2)
O4	0.050 (6)	0.040 (5)	0.041 (6)	−0.001 (5)	0.009 (5)	0.008 (5)

Geometric parameters (Å, º) top

Br1—Co1	2.5467 (12)	C9—C10	1.386 (11)
C1—C2	1.376 (10)	C9—H9	0.9300
C1—N1	1.384 (10)	C10—C11	1.403 (12)
C1—H1	0.9300	C10—H10	0.9300
C2—C3	1.394 (11)	C11—C12	1.394 (11)
C2—H2	0.9300	C11—H11	0.9300
C3—C4	1.405 (11)	C12—N2	1.370 (9)
C3—H3	0.9300	C12—C13	1.474 (11)
C4—C5	1.407 (10)	C13—O3	1.328 (10)
C4—H4	0.9300	C13—H13A	0.9700
C5—N1	1.366 (10)	C13—H13B	0.9700
C5—C6	1.422 (10)	Co1—O1ⁱ	2.043 (5)
C6—O1	1.381 (8)	Co1—N1	2.073 (6)
C6—H6A	0.9700	Co1—O1	2.079 (5)
C6—H6B	0.9700	Co1—O1ⁱⁱ	2.123 (5)
C7—O2	1.469 (9)	Co1—O2	2.196 (5)
C7—H7A	0.9600	O1—Co1ⁱⁱⁱ	2.043 (5)
C7—H7B	0.9600	O1—Co1ⁱⁱ	2.123 (5)
C7—H7C	0.9600	O2—H2B	0.9700
C8—C9	1.362 (10)	O3—H3A	0.9601
C8—N2	1.415 (10)	O4—H4A	0.9700
C8—H8	0.9300	O4—H4B	0.9700

C2—C1—N1	119.4 (6)	N2—C12—C11	120.5 (7)
C2—C1—H1	120.3	N2—C12—C13	117.2 (7)
N1—C1—H1	120.3	C11—C12—C13	122.3 (7)
C1—C2—C3	120.8 (7)	O3—C13—C12	106.6 (7)
C1—C2—H2	119.6	O3—C13—H13A	110.4
C3—C2—H2	119.6	C12—C13—H13A	110.4
C2—C3—C4	119.2 (6)	O3—C13—H13B	110.4
C2—C3—H3	120.4	C12—C13—H13B	110.4
C4—C3—H3	120.4	H13A—C13—H13B	108.6
C3—C4—C5	119.5 (7)	O1ⁱ—Co1—N1	158.0 (2)
C3—C4—H4	120.3	O1ⁱ—Co1—O1	80.55 (19)
C5—C4—H4	120.3	N1—Co1—O1	79.1 (2)
N1—C5—C4	119.4 (7)	O1ⁱ—Co1—O1ⁱⁱ	79.5 (2)
N1—C5—C6	116.1 (6)	N1—Co1—O1ⁱⁱ	105.2 (2)
C4—C5—C6	123.1 (7)	O1—Co1—O1ⁱⁱ	80.5 (2)
O1—C6—C5	116.6 (6)	O1ⁱ—Co1—O2	89.86 (19)
O1—C6—H6A	108.1	N1—Co1—O2	82.9 (2)
C5—C6—H6A	108.1	O1—Co1—O2	93.03 (19)
O1—C6—H6B	108.1	O1ⁱⁱ—Co1—O2	168.29 (18)
C5—C6—H6B	108.1	O1ⁱ—Co1—Br1	101.00 (14)
H6A—C6—H6B	107.3	N1—Co1—Br1	99.94 (17)
O2—C7—H7A	109.5	O1—Co1—Br1	175.05 (15)
O2—C7—H7B	109.5	O1ⁱⁱ—Co1—Br1	95.13 (14)
H7A—C7—H7B	109.5	O2—Co1—Br1	91.68 (13)
O2—C7—H7C	109.5	C5—N1—C1	121.6 (6)
H7A—C7—H7C	109.5	C5—N1—Co1	112.1 (5)
H7B—C7—H7C	109.5	C1—N1—Co1	126.3 (5)
C9—C8—N2	119.9 (8)	C12—N2—C8	119.6 (6)
C9—C8—H8	120.0	C6—O1—Co1ⁱⁱⁱ	130.8 (4)
N2—C8—H8	120.0	C6—O1—Co1	110.1 (4)
C8—C9—C10	121.0 (8)	Co1ⁱⁱⁱ—O1—Co1	99.9 (2)
C8—C9—H9	119.5	C6—O1—Co1ⁱⁱ	113.7 (5)
C10—C9—H9	119.5	Co1ⁱⁱⁱ—O1—Co1ⁱⁱ	98.49 (19)
C9—C10—C11	119.3 (7)	Co1—O1—Co1ⁱⁱ	98.7 (2)
C9—C10—H10	120.3	C7—O2—Co1	136.3 (4)
C11—C10—H10	120.3	C7—O2—H2B	102.3
C12—C11—C10	119.6 (8)	Co1—O2—H2B	99.6
C12—C11—H11	120.2	C13—O3—H3A	108.8
C10—C11—H11	120.2	H4A—O4—H4B	101.6

N1—C1—C2—C3	1.3 (12)	O2—Co1—N1—C1	−102.6 (6)
C1—C2—C3—C4	−0.1 (12)	Br1—Co1—N1—C1	−12.1 (6)
C2—C3—C4—C5	−2.0 (12)	C11—C12—N2—C8	0.3 (11)
C3—C4—C5—N1	3.0 (12)	C13—C12—N2—C8	−176.7 (7)
C3—C4—C5—C6	169.2 (8)	C9—C8—N2—C12	−0.1 (11)
N1—C5—C6—O1	6.7 (11)	C5—C6—O1—Co1ⁱⁱⁱ	−146.0 (6)
C4—C5—C6—O1	−159.9 (7)	C5—C6—O1—Co1	−22.0 (8)
N2—C8—C9—C10	−1.0 (11)	C5—C6—O1—Co1ⁱⁱ	87.7 (7)
C8—C9—C10—C11	1.8 (12)	O1ⁱ—Co1—O1—C6	−150.0 (5)
C9—C10—C11—C12	−1.5 (11)	N1—Co1—O1—C6	21.6 (5)
C10—C11—C12—N2	0.5 (12)	O1ⁱⁱ—Co1—O1—C6	129.2 (4)
C10—C11—C12—C13	177.4 (7)	O2—Co1—O1—C6	−60.7 (5)
N2—C12—C13—O3	−30.4 (10)	Br1—Co1—O1—C6	101.3 (16)
C11—C12—C13—O3	152.6 (7)	O1ⁱ—Co1—O1—Co1ⁱⁱⁱ	−9.59 (19)
C4—C5—N1—C1	−1.9 (10)	N1—Co1—O1—Co1ⁱⁱⁱ	162.0 (3)
C6—C5—N1—C1	−169.1 (7)	O1ⁱⁱ—Co1—O1—Co1ⁱⁱⁱ	−90.4 (2)
C4—C5—N1—Co1	179.5 (6)	O2—Co1—O1—Co1ⁱⁱⁱ	79.8 (2)
C6—C5—N1—Co1	12.4 (8)	Br1—Co1—O1—Co1ⁱⁱⁱ	−118.2 (15)
C2—C1—N1—C5	−0.2 (11)	O1ⁱ—Co1—O1—Co1ⁱⁱ	90.7 (2)
C2—C1—N1—Co1	178.1 (6)	N1—Co1—O1—Co1ⁱⁱ	−97.7 (2)
O1ⁱ—Co1—N1—C5	4.2 (9)	O1ⁱⁱ—Co1—O1—Co1ⁱⁱ	9.9 (3)
O1—Co1—N1—C5	−18.6 (5)	O2—Co1—O1—Co1ⁱⁱ	−179.97 (19)
O1ⁱⁱ—Co1—N1—C5	−95.5 (5)	Br1—Co1—O1—Co1ⁱⁱ	−18.0 (17)
O2—Co1—N1—C5	75.9 (5)	O1ⁱ—Co1—O2—C7	−160.9 (6)
Br1—Co1—N1—C5	166.4 (5)	N1—Co1—O2—C7	39.9 (6)
O1ⁱ—Co1—N1—C1	−174.3 (6)	O1—Co1—O2—C7	118.6 (6)
O1—Co1—N1—C1	163.0 (6)	O1ⁱⁱ—Co1—O2—C7	174.5 (9)
O1ⁱⁱ—Co1—N1—C1	86.1 (6)	Br1—Co1—O2—C7	−59.9 (6)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2B···Br1ⁱⁱⁱ	0.97	2.54	3.217 (5)	127
O3—H3A···O3^iv	0.96	2.31	3.030 (9)	132
O3—H3A···O4^v	0.96	2.57	3.370 (11)	141

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

Experimental details

Crystal data
Chemical formula	[Co₄Br₄(C₆H₆NO)₄(CH₄O)₄]Br₄·4C₆H₇NO₄·2H₂O
M_r	1908.10
Crystal system, space group	Tetragonal, I4₂d
Temperature (K)	291
a, c (Å)	16.5302 (6), 29.875 (2)
V (Å³)	8163.3 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	4.77
Crystal size (mm)	0.30 × 0.24 × 0.22

Data collection
Diffractometer	Bruker SMART APEX CCD area-detector
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.265, 0.350
No. of measured, independent and observed [I > 2σ(I)] reflections	21461, 4018, 3180
R_int	0.056
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.113, 0.99
No. of reflections	4018
No. of parameters	200
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.75, −0.56
Absolute structure	Flack (1983), 1822 Friedel pairs
Absolute structure parameter	0.025 (18)

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2B···Br1ⁱ	0.97	2.54	3.217 (5)	126.9
O3—H3A···O3ⁱⁱ	0.96	2.31	3.030 (9)	131.5
O3—H3A···O4ⁱⁱⁱ	0.96	2.57	3.370 (11)	140.9

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

Acknowledgements

This work was supported by the National Basic Research program of China (2007CB925102), the National Natural Science Foundation of China (NSFC: 20771056), the State Basic Research Project of China (NSFC: 20490218) and the Center of Analysis and Determining of Nanjing University.

References

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