Tetra­kis(μ2-2,2-dimethyl­propanoato-κ2O,O′)bis­[(pyridine-κN)copper(II)]: a monoclinic polymorph

Ozair, L.N.; Abdullah, N.; Khaledi, H.; Tiekink, E.R.T.

doi:10.1107/S1600536810015060

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 5| May 2010| Pages m589-m590

https://doi.org/10.1107/S1600536810015060

Open

access

Tetrakis(μ₂-2,2-dimethylpropanoato-κ²O,O′)bis[(pyridine-κN)copper(II)]: a monoclinic polymorph

Lailatun Nazirah Ozair,^a Norbani Abdullah,^a ‡ Hamid Khaledi ^a and Edward R. T. Tiekink ^a ^*

^aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: edward.tiekink@gmail.com

(Received 23 April 2010; accepted 24 April 2010; online 30 April 2010)

The structure of the dinuclear title complex, [Cu₂(C₅H₉O₂)₄(C₅H₅N)₂], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006 ). Acta Cryst. E62, m420–m422]. Each carboxylate group is bidentate bridging and the distorted octahedral geometry about each Cu^II atom is completed by a pyridine N atom and the other Cu atom [Cu⋯Cu = 2.6139 (7) Å]. In the crystal, molecules are connected into supramolecular chains via π–π interactions formed by the pyridine rings [centroid–centroid distance = 3.552 (3) Å] and these are connected into a two-dimensional array in the ac plane by C—H⋯π contacts. One of the tert-butyl groups is disordered over two orientations in a 0.734 (6):0.266 (6) ratio.

Related literature

For the structure of the triclinic polymorph of the title compound, see: Blewett et al. (2006). For background to copper(II) carboxylates, see: Attard & Cullum (1990 ); Kato et al. (1964 ); Melnik et al. (1984 ); Kawata et al. (1992 ).

Experimental

Crystal data

[Cu₂(C₅H₉O₂)₄(C₅H₅N)₂]
M_r = 689.80
Monoclinic, P 2₁ /n
a = 9.4758 (6) Å
b = 20.0192 (12) Å
c = 18.6136 (10) Å
β = 104.515 (3)°
V = 3418.3 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.29 mm⁻¹
T = 100 K
0.32 × 0.26 × 0.16 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.682, T_max = 0.820
28775 measured reflections
7077 independent reflections
5583 reflections with I > 2σ(I)
R_int = 0.060

Refinement

R[F² > 2σ(F²)] = 0.058
wR(F²) = 0.156
S = 1.13
7077 reflections
404 parameters
12 restraints
H-atom parameters constrained
Δρ_max = 1.26 e Å⁻³
Δρ_min = −0.75 e Å⁻³

Table 1
Selected bond lengths (Å)

Cu1—O7	1.950 (3)
Cu1—O1	1.956 (3)
Cu1—O3	1.976 (3)
Cu1—O5	1.987 (3)
Cu1—N1	2.157 (3)
Cu2—O6	1.962 (3)
Cu2—O4	1.968 (3)
Cu2—O8	1.976 (3)
Cu2—O2	1.978 (3)
Cu2—N2	2.157 (3)

Table 2
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of the N1,C21–C25 and N2,C26–C30 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3c⋯Cg1ⁱ	0.98	2.90	3.609 (7)	130
C19b—H19f⋯Cg2ⁱⁱ	0.98	2.64	3.554 (19)	154
Symmetry codes: (i) x-1, y, z; (ii) x+1, y, z.

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810015060/hb5416sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810015060/hb5416Isup2.hkl

checkCIF report

Comment top

Research on copper(II) carboxylates focuses upon their metallomesogenic properties (Attard & Cullum, 1990) and interesting magneto-structural relationship (Kato et al., 1964; Melnik et al., 1984; Kawata et al., 1992). However, the practical use of these complexes is hindered by their high melting points (greater than 523 K) and which are accompanied by thermal decomposition. Our research interest is to develop low-temperature copper(II) carboxylates as functional materials for use in the fields of catalysis, photonics, spintronics, and electronics. To realise this, we adopted the concepts of symmetry reduction by mixed ligands and the use of highly-branched alkylcarboxylates. This contribution reports the crystal structure of one of the starting materials to be used in the synthesis of such complexes, i.e. the title compound, (I).

The dinuclear structure of (I), Fig. 1, features two Cu atoms, separated by 2.6139 (7) Å, connected by four bidentate bridging carboxylate ligands. The final position in the disordered octahedral trans-CuNO₄ donor set is occupied by a pyridine-N atom in each case. The structure resembles closely that described for the triclinic polymorph but with the latter being disposed about a centre of inversion (Blewett et al., 2006). The primary differences between the molecules is found in the relative disposition of the pyridine groups. In (I), the dihedral angles formed between the least-squares planes through the four O atoms and pyridine ring = 81.5 (1) ° for Cu1 and 88.6 (1) ° for Cu2, which compares to 89.38 (8) ° found in the triclinic structure. These differences are reflected in the dihedral angle of 12.93 (15) ° formed between the pyridine rings in (I) compared to 0 ° (from symmetry) in the triclinic polymorph. These differences not withstanding, the Cu–O bond distances are experimentally equivalent in the two forms but it is noted these cover are broader range in (I), i.e. 1.950 (3) to 1.987 (3) Å, compared with 1.963 (2) to 1.977 (2) Å; the Cu–N distances are indistinguishable. The Cu···Cu distance in (I), 2.6139 (7) Å, is shorter than 2.6229 (9) Å in the triclinic form.

A common feature of the crystal packing of both forms is the presence of significant π–π interactions between the pyridine rings. In (I), these [ring centroid(N1,C21—C25)···ring centroid(N2,C26—C30)ⁱ = 3.552 (3) Å, angle between planes = 9.2 (2) °, for i: 1/2+x, 1/2-y, 1/2+z] lead to supramolecular chains which are connected into a 2-D array in the ac plane by C–H···π contacts involving methyl-H atoms (one being derived from a disordered tert-butyl residue), Fig. 2 & Table 1. The layers are stacked along the b direction as illustrated in Fig. 3.

Related literature top

For the structure of the triclinic polymorph of the title compound, see: Blewett et al. (2006). For background to copper(II) carboxylates, see: Attard & Cullum (1990); Kato et al. (1964); Melnik et al. (1984); Kawata et al. (1992).

Experimental top

An aqueous solution (50 ml) of sodium carbonate (5.2 g, 0.049 mol) was added to an aqueous solution (50 ml) of 2,2-dimethylpropionic acid (10 g, 0.098 mol) and the mixture was stirred at 323 K. After 30 min, a solution of CuCl₂.2H₂O (8.33 g, 0.049 mol) dissolved in a minimum amount of water was added followed by addition of several drops of pyridine. The mixture was stirred for another 30 min. and then set aside at room temperature for a week whereupon green blocks of (I) were obtained. Both DSC and TGA data indicate that the material did not melt, but decomposed at 408 K. CHN analyses (%), Found: C, 52.17; H, 6.75; N, 4.16. Calc'd: C, 52.23; H, 6.72; N, 4.05.

Structure description top

For the structure of the triclinic polymorph of the title compound, see: Blewett et al. (2006). For background to copper(II) carboxylates, see: Attard & Cullum (1990); Kato et al. (1964); Melnik et al. (1984); Kawata et al. (1992).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 50% probability level. Only the major component of the disordered tert-butyl group is shown for reasons of clarity.
	Fig. 2. The 2-D array in the ac plane in (I) mediated by π–π and C–H···π interactions, shown as purple and orange dashed lines, respectively. Colour code: Cu, orange; O, red; N, blue; C, grey; and H, green.
	Fig. 3. Packing of layers in (I) along the b axis. Colour code: Cu, orange; O, red; N, blue; C, grey; and H, green.

Tetrakis(µ₂-2,2-dimethylpropanoato-κ²O,O')bis[(pyridine- κN)copper(II)] top

Crystal data top

[Cu₂(C₅H₉O₂)₄(C₅H₅N)₂]	F(000) = 1448
M_r = 689.80	D_x = 1.340 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6465 reflections
a = 9.4758 (6) Å	θ = 2.2–28.4°
b = 20.0192 (12) Å	µ = 1.29 mm⁻¹
c = 18.6136 (10) Å	T = 100 K
β = 104.515 (3)°	Block, green
V = 3418.3 (4) Å³	0.32 × 0.26 × 0.16 mm
Z = 4

Data collection top

Bruker SMART APEX CCD diffractometer	7077 independent reflections
Radiation source: fine-focus sealed tube	5583 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.060
ω scans	θ_max = 26.5°, θ_min = 1.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→11
T_min = 0.682, T_max = 0.820	k = −25→25
28775 measured reflections	l = −23→23

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.156	H-atom parameters constrained
S = 1.13	w = 1/[σ²(F_o²) + (0.0532P)² + 12.7516P] where P = (F_o² + 2F_c²)/3
7077 reflections	(Δ/σ)_max = 0.001
404 parameters	Δρ_max = 1.26 e Å⁻³
12 restraints	Δρ_min = −0.75 e Å⁻³

Crystal data top

[Cu₂(C₅H₉O₂)₄(C₅H₅N)₂]	V = 3418.3 (4) Å³
M_r = 689.80	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 9.4758 (6) Å	µ = 1.29 mm⁻¹
b = 20.0192 (12) Å	T = 100 K
c = 18.6136 (10) Å	0.32 × 0.26 × 0.16 mm
β = 104.515 (3)°

Data collection top

Bruker SMART APEX CCD diffractometer	7077 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	5583 reflections with I > 2σ(I)
T_min = 0.682, T_max = 0.820	R_int = 0.060
28775 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.058	12 restraints
wR(F²) = 0.156	H-atom parameters constrained
S = 1.13	w = 1/[σ²(F_o²) + (0.0532P)² + 12.7516P] where P = (F_o² + 2F_c²)/3
7077 reflections	Δρ_max = 1.26 e Å⁻³
404 parameters	Δρ_min = −0.75 e Å⁻³

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Cu1	0.45858 (5)	0.21308 (2)	0.12035 (3)	0.01076 (14)
Cu2	0.26828 (5)	0.28113 (2)	0.02145 (3)	0.01059 (14)
O1	0.2929 (3)	0.15985 (17)	0.13229 (18)	0.0249 (8)
O2	0.1310 (3)	0.21490 (17)	0.04446 (18)	0.0234 (7)
O3	0.4621 (4)	0.15777 (16)	0.03288 (17)	0.0246 (8)
O4	0.3063 (4)	0.21771 (15)	−0.05224 (16)	0.0206 (7)
O5	0.4194 (4)	0.27884 (16)	0.19295 (16)	0.0227 (7)
O6	0.2568 (3)	0.33601 (16)	0.10715 (16)	0.0219 (7)
O7	0.5986 (3)	0.27532 (16)	0.09663 (18)	0.0233 (7)
O8	0.4386 (3)	0.33408 (16)	0.01196 (18)	0.0217 (7)
N1	0.6203 (4)	0.15694 (17)	0.19951 (18)	0.0127 (7)
N2	0.1082 (4)	0.34034 (17)	−0.05504 (18)	0.0114 (7)
C1	0.1662 (5)	0.1693 (2)	0.0920 (2)	0.0162 (9)
C2	0.0475 (5)	0.1208 (2)	0.1027 (3)	0.0229 (10)
C3	0.0191 (7)	0.1362 (4)	0.1771 (3)	0.0458 (16)
H3A	−0.0212	0.1813	0.1763	0.069*
H3B	0.1106	0.1334	0.2157	0.069*
H3C	−0.0507	0.1038	0.1876	0.069*
C4	0.1053 (7)	0.0488 (3)	0.1029 (4)	0.0405 (14)
H4A	0.1948	0.0440	0.1426	0.061*
H4B	0.1262	0.0393	0.0549	0.061*
H4C	0.0317	0.0175	0.1112	0.061*
C5	−0.0901 (6)	0.1281 (4)	0.0406 (4)	0.0524 (19)
H5A	−0.1589	0.0925	0.0446	0.079*
H5B	−0.0656	0.1246	−0.0074	0.079*
H5C	−0.1347	0.1716	0.0444	0.079*
C6	0.3892 (4)	0.1687 (2)	−0.0318 (2)	0.0134 (8)
C7	0.3937 (5)	0.1150 (2)	−0.0905 (2)	0.0151 (9)
C8	0.5456 (5)	0.0838 (3)	−0.0754 (3)	0.0260 (11)
H8A	0.5710	0.0643	−0.0255	0.039*
H8B	0.6170	0.1183	−0.0789	0.039*
H8C	0.5462	0.0488	−0.1121	0.039*
C9	0.2810 (5)	0.0621 (2)	−0.0821 (3)	0.0232 (10)
H9A	0.3111	0.0419	−0.0326	0.035*
H9B	0.2749	0.0273	−0.1199	0.035*
H9C	0.1854	0.0832	−0.0884	0.035*
C10	0.3515 (5)	0.1443 (2)	−0.1687 (2)	0.0230 (10)
H10A	0.3551	0.1091	−0.2049	0.035*
H10B	0.4198	0.1800	−0.1728	0.035*
H10C	0.2525	0.1625	−0.1787	0.035*
C11	0.3319 (5)	0.3263 (2)	0.1724 (2)	0.0146 (8)
C12	0.3165 (5)	0.3794 (2)	0.2300 (2)	0.0188 (9)
C13	0.1568 (6)	0.3994 (3)	0.2176 (3)	0.0307 (12)
H13A	0.1483	0.4348	0.2526	0.046*
H13B	0.0997	0.3605	0.2256	0.046*
H13C	0.1200	0.4156	0.1667	0.046*
C14	0.4075 (6)	0.4394 (3)	0.2171 (3)	0.0332 (12)
H14A	0.3725	0.4548	0.1657	0.050*
H14B	0.5100	0.4262	0.2263	0.050*
H14C	0.3980	0.4756	0.2510	0.050*
C15	0.3755 (5)	0.3530 (3)	0.3093 (2)	0.0244 (10)
H15A	0.3713	0.3886	0.3449	0.037*
H15B	0.4767	0.3385	0.3160	0.037*
H15C	0.3161	0.3151	0.3177	0.037*
C16	0.5650 (5)	0.3216 (2)	0.0502 (2)	0.0140 (8)
C17A	0.6897 (5)	0.3671 (2)	0.0410 (2)	0.0239 (10)	0.734 (6)
C18A	0.8277 (7)	0.3287 (4)	0.0437 (5)	0.0402 (19)	0.734 (6)
H18A	0.8152	0.3020	−0.0016	0.060*	0.734 (6)
H18B	0.8489	0.2990	0.0870	0.060*	0.734 (6)
H18C	0.9087	0.3600	0.0475	0.060*	0.734 (6)
C19A	0.6466 (8)	0.4147 (4)	−0.0237 (4)	0.0373 (19)	0.734 (6)
H19A	0.7232	0.4483	−0.0203	0.056*	0.734 (6)
H19B	0.5550	0.4369	−0.0226	0.056*	0.734 (6)
H19C	0.6336	0.3898	−0.0702	0.056*	0.734 (6)
C20A	0.7221 (9)	0.4117 (4)	0.1122 (4)	0.0397 (19)	0.734 (6)
H20A	0.7620	0.3840	0.1559	0.060*	0.734 (6)
H20B	0.6317	0.4329	0.1169	0.060*	0.734 (6)
H20C	0.7930	0.4463	0.1082	0.060*	0.734 (6)
C17B	0.6897 (5)	0.3671 (2)	0.0410 (2)	0.0239 (10)	0.266 (6)
C18B	0.8322 (14)	0.3532 (12)	0.0968 (11)	0.0402 (19)	0.266 (6)
H18D	0.9104	0.3785	0.0835	0.060*	0.266 (6)
H18E	0.8540	0.3053	0.0969	0.060*	0.266 (6)
H18F	0.8247	0.3666	0.1464	0.060*	0.266 (6)
C19B	0.711 (2)	0.3343 (10)	−0.0311 (8)	0.0373 (19)	0.266 (6)
H19D	0.6414	0.3536	−0.0741	0.056*	0.266 (6)
H19E	0.6943	0.2860	−0.0295	0.056*	0.266 (6)
H19F	0.8106	0.3425	−0.0353	0.056*	0.266 (6)
C20B	0.636 (2)	0.4363 (6)	0.0178 (13)	0.0397 (19)	0.266 (6)
H20D	0.5969	0.4566	0.0568	0.060*	0.266 (6)
H20E	0.5582	0.4339	−0.0283	0.060*	0.266 (6)
H20F	0.7162	0.4635	0.0097	0.060*	0.266 (6)
C21	0.6186 (5)	0.0903 (2)	0.2011 (3)	0.0212 (10)
H21	0.5543	0.0671	0.1615	0.025*
C22	0.7063 (6)	0.0535 (2)	0.2577 (3)	0.0266 (11)
H22	0.7017	0.0061	0.2572	0.032*
C23	0.8012 (5)	0.0870 (3)	0.3153 (2)	0.0247 (11)
H23	0.8628	0.0629	0.3549	0.030*
C24	0.8046 (5)	0.1551 (3)	0.3142 (2)	0.0234 (10)
H24	0.8681	0.1793	0.3531	0.028*
C25	0.7131 (5)	0.1884 (2)	0.2548 (2)	0.0215 (10)
H25	0.7170	0.2358	0.2536	0.026*
C26	0.0947 (5)	0.4055 (2)	−0.0447 (2)	0.0173 (9)
H26	0.1561	0.4256	−0.0020	0.021*
C27	−0.0046 (5)	0.4454 (2)	−0.0933 (3)	0.0246 (10)
H27	−0.0134	0.4915	−0.0833	0.030*
C28	−0.0911 (5)	0.4162 (3)	−0.1571 (3)	0.0259 (11)
H28	−0.1586	0.4425	−0.1922	0.031*
C29	−0.0778 (5)	0.3487 (3)	−0.1689 (3)	0.0242 (10)
H29	−0.1361	0.3276	−0.2119	0.029*
C30	0.0230 (5)	0.3123 (2)	−0.1163 (2)	0.0182 (9)
H30	0.0320	0.2657	−0.1239	0.022*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0098 (2)	0.0124 (3)	0.0083 (2)	−0.00001 (19)	−0.00105 (18)	0.00013 (18)
Cu2	0.0095 (2)	0.0119 (3)	0.0086 (2)	−0.00012 (19)	−0.00098 (18)	0.00001 (18)
O1	0.0145 (16)	0.0320 (19)	0.0222 (17)	−0.0075 (14)	−0.0069 (13)	0.0127 (14)
O2	0.0133 (15)	0.0284 (18)	0.0257 (17)	−0.0046 (13)	−0.0005 (13)	0.0113 (14)
O3	0.0311 (19)	0.0243 (18)	0.0120 (15)	0.0147 (14)	−0.0063 (13)	−0.0042 (13)
O4	0.0292 (18)	0.0195 (16)	0.0103 (14)	0.0108 (14)	−0.0002 (13)	−0.0005 (12)
O5	0.0270 (18)	0.0248 (18)	0.0126 (15)	0.0133 (14)	−0.0021 (13)	−0.0028 (13)
O6	0.0237 (17)	0.0254 (17)	0.0123 (15)	0.0105 (14)	−0.0032 (13)	−0.0040 (13)
O7	0.0134 (15)	0.0272 (18)	0.0266 (17)	−0.0039 (13)	−0.0001 (13)	0.0112 (14)
O8	0.0130 (15)	0.0225 (17)	0.0266 (17)	−0.0031 (13)	−0.0010 (13)	0.0084 (13)
N1	0.0112 (17)	0.0171 (18)	0.0079 (16)	0.0042 (14)	−0.0012 (13)	−0.0012 (13)
N2	0.0096 (16)	0.0158 (17)	0.0089 (16)	−0.0004 (13)	0.0022 (13)	0.0010 (13)
C1	0.019 (2)	0.019 (2)	0.0090 (19)	−0.0055 (17)	0.0001 (16)	−0.0002 (16)
C2	0.017 (2)	0.029 (3)	0.021 (2)	−0.0090 (19)	0.0013 (18)	0.0088 (19)
C3	0.036 (3)	0.072 (5)	0.037 (3)	−0.017 (3)	0.023 (3)	−0.005 (3)
C4	0.046 (4)	0.026 (3)	0.052 (4)	−0.013 (3)	0.017 (3)	0.006 (3)
C5	0.027 (3)	0.060 (4)	0.055 (4)	−0.026 (3)	−0.018 (3)	0.026 (3)
C6	0.013 (2)	0.014 (2)	0.0116 (19)	−0.0021 (16)	0.0015 (16)	0.0010 (16)
C7	0.014 (2)	0.019 (2)	0.0113 (19)	0.0026 (17)	0.0004 (16)	−0.0039 (16)
C8	0.025 (3)	0.028 (3)	0.024 (2)	0.010 (2)	0.003 (2)	−0.005 (2)
C9	0.031 (3)	0.018 (2)	0.020 (2)	−0.006 (2)	0.006 (2)	−0.0052 (18)
C10	0.029 (3)	0.026 (3)	0.012 (2)	0.008 (2)	0.0003 (19)	−0.0005 (18)
C11	0.015 (2)	0.016 (2)	0.014 (2)	0.0002 (17)	0.0057 (17)	−0.0002 (16)
C12	0.026 (2)	0.014 (2)	0.015 (2)	0.0071 (18)	0.0036 (18)	0.0018 (17)
C13	0.028 (3)	0.044 (3)	0.019 (2)	0.020 (2)	0.003 (2)	0.000 (2)
C14	0.047 (3)	0.022 (3)	0.029 (3)	−0.008 (2)	0.008 (2)	−0.007 (2)
C15	0.031 (3)	0.030 (3)	0.010 (2)	0.012 (2)	0.0025 (19)	−0.0015 (18)
C16	0.014 (2)	0.020 (2)	0.0075 (18)	−0.0022 (17)	0.0009 (16)	−0.0057 (16)
C17A	0.015 (2)	0.035 (3)	0.022 (2)	−0.002 (2)	0.0027 (19)	0.007 (2)
C18A	0.021 (3)	0.044 (5)	0.062 (5)	0.001 (3)	0.022 (4)	0.008 (4)
C19A	0.019 (3)	0.048 (4)	0.041 (4)	−0.011 (3)	0.001 (3)	0.021 (4)
C20A	0.039 (4)	0.047 (5)	0.035 (4)	−0.028 (4)	0.012 (3)	−0.013 (3)
C17B	0.015 (2)	0.035 (3)	0.022 (2)	−0.002 (2)	0.0027 (19)	0.007 (2)
C18B	0.021 (3)	0.044 (5)	0.062 (5)	0.001 (3)	0.022 (4)	0.008 (4)
C19B	0.019 (3)	0.048 (4)	0.041 (4)	−0.011 (3)	0.001 (3)	0.021 (4)
C20B	0.039 (4)	0.047 (5)	0.035 (4)	−0.028 (4)	0.012 (3)	−0.013 (3)
C21	0.024 (2)	0.017 (2)	0.020 (2)	0.0008 (19)	0.0002 (18)	−0.0012 (18)
C22	0.033 (3)	0.018 (2)	0.027 (3)	0.008 (2)	0.003 (2)	0.0081 (19)
C23	0.017 (2)	0.039 (3)	0.015 (2)	0.012 (2)	−0.0027 (18)	0.011 (2)
C24	0.017 (2)	0.040 (3)	0.010 (2)	0.004 (2)	−0.0015 (17)	−0.0037 (19)
C25	0.019 (2)	0.023 (2)	0.018 (2)	0.0034 (19)	−0.0050 (18)	−0.0082 (18)
C26	0.016 (2)	0.017 (2)	0.016 (2)	−0.0021 (17)	−0.0009 (17)	0.0010 (17)
C27	0.023 (2)	0.019 (2)	0.030 (3)	0.0036 (19)	0.003 (2)	0.004 (2)
C28	0.023 (2)	0.036 (3)	0.016 (2)	0.008 (2)	0.0007 (19)	0.009 (2)
C29	0.016 (2)	0.036 (3)	0.017 (2)	0.006 (2)	−0.0017 (18)	−0.004 (2)
C30	0.013 (2)	0.024 (2)	0.015 (2)	0.0032 (18)	−0.0026 (17)	−0.0068 (17)

Geometric parameters (Å, º) top

Cu1—O7	1.950 (3)	C13—H13A	0.9800
Cu1—O1	1.956 (3)	C13—H13B	0.9800
Cu1—O3	1.976 (3)	C13—H13C	0.9800
Cu1—O5	1.987 (3)	C14—H14A	0.9800
Cu1—N1	2.157 (3)	C14—H14B	0.9800
Cu1—Cu2	2.6139 (7)	C14—H14C	0.9800
Cu2—O6	1.962 (3)	C15—H15A	0.9800
Cu2—O4	1.968 (3)	C15—H15B	0.9800
Cu2—O8	1.976 (3)	C15—H15C	0.9800
Cu2—O2	1.978 (3)	C16—C17B	1.535 (6)
Cu2—N2	2.157 (3)	C16—C17A	1.535 (6)
O1—C1	1.261 (5)	C17A—C18A	1.506 (7)
O2—C1	1.257 (5)	C17A—C19A	1.510 (6)
O3—C6	1.247 (5)	C17A—C20A	1.563 (7)
O4—C6	1.255 (5)	C18A—H18A	0.9800
O5—C11	1.256 (5)	C18A—H18B	0.9800
O6—C11	1.260 (5)	C18A—H18C	0.9800
O7—C16	1.253 (5)	C19A—H19A	0.9800
O8—C16	1.255 (5)	C19A—H19B	0.9800
N1—C25	1.332 (5)	C19A—H19C	0.9800
N1—C21	1.335 (6)	C20A—H20A	0.9800
N2—C26	1.329 (5)	C20A—H20B	0.9800
N2—C30	1.343 (5)	C20A—H20C	0.9800
C1—C2	1.535 (6)	C17B—C20B	1.503 (10)
C2—C3	1.506 (7)	C17B—C18B	1.508 (9)
C2—C5	1.518 (7)	C17B—C19B	1.553 (9)
C2—C4	1.541 (8)	C18B—H18D	0.9800
C3—H3A	0.9800	C18B—H18E	0.9800
C3—H3B	0.9800	C18B—H18F	0.9800
C3—H3C	0.9800	C19B—H19D	0.9800
C4—H4A	0.9800	C19B—H19E	0.9800
C4—H4B	0.9800	C19B—H19F	0.9800
C4—H4C	0.9800	C20B—H20D	0.9800
C5—H5A	0.9800	C20B—H20E	0.9800
C5—H5B	0.9800	C20B—H20F	0.9800
C5—H5C	0.9800	C21—C22	1.379 (6)
C6—C7	1.541 (6)	C21—H21	0.9500
C7—C10	1.527 (6)	C22—C23	1.388 (7)
C7—C8	1.530 (6)	C22—H22	0.9500
C7—C9	1.540 (6)	C23—C24	1.364 (7)
C8—H8A	0.9800	C23—H23	0.9500
C8—H8B	0.9800	C24—C25	1.392 (6)
C8—H8C	0.9800	C24—H24	0.9500
C9—H9A	0.9800	C25—H25	0.9500
C9—H9B	0.9800	C26—C27	1.383 (6)
C9—H9C	0.9800	C26—H26	0.9500
C10—H10A	0.9800	C27—C28	1.391 (7)
C10—H10B	0.9800	C27—H27	0.9500
C10—H10C	0.9800	C28—C29	1.380 (7)
C11—C12	1.542 (6)	C28—H28	0.9500
C12—C13	1.526 (6)	C29—C30	1.391 (6)
C12—C14	1.532 (7)	C29—H29	0.9500
C12—C15	1.535 (6)	C30—H30	0.9500

O7—Cu1—O1	170.12 (13)	C7—C10—H10C	109.5
O7—Cu1—O3	91.07 (15)	H10A—C10—H10C	109.5
O1—Cu1—O3	88.17 (15)	H10B—C10—H10C	109.5
O7—Cu1—O5	89.11 (15)	O5—C11—O6	125.5 (4)
O1—Cu1—O5	89.51 (15)	O5—C11—C12	118.7 (4)
O3—Cu1—O5	167.45 (12)	O6—C11—C12	115.8 (4)
O7—Cu1—N1	94.62 (13)	C13—C12—C14	110.2 (4)
O1—Cu1—N1	95.25 (13)	C13—C12—C15	110.1 (4)
O3—Cu1—N1	96.60 (13)	C14—C12—C15	109.7 (4)
O5—Cu1—N1	95.89 (12)	C13—C12—C11	109.8 (4)
O7—Cu1—Cu2	84.03 (9)	C14—C12—C11	106.1 (4)
O1—Cu1—Cu2	86.11 (9)	C15—C12—C11	110.9 (3)
O3—Cu1—Cu2	82.12 (9)	C12—C13—H13A	109.5
O5—Cu1—Cu2	85.42 (9)	C12—C13—H13B	109.5
N1—Cu1—Cu2	178.11 (9)	H13A—C13—H13B	109.5
O6—Cu2—O4	170.13 (12)	C12—C13—H13C	109.5
O6—Cu2—O8	89.16 (14)	H13A—C13—H13C	109.5
O4—Cu2—O8	89.27 (14)	H13B—C13—H13C	109.5
O6—Cu2—O2	91.47 (14)	C12—C14—H14A	109.5
O4—Cu2—O2	87.93 (14)	C12—C14—H14B	109.5
O8—Cu2—O2	167.25 (13)	H14A—C14—H14B	109.5
O6—Cu2—N2	93.19 (13)	C12—C14—H14C	109.5
O4—Cu2—N2	96.66 (12)	H14A—C14—H14C	109.5
O8—Cu2—N2	95.82 (12)	H14B—C14—H14C	109.5
O2—Cu2—N2	96.86 (13)	C12—C15—H15A	109.5
O6—Cu2—Cu1	83.59 (9)	C12—C15—H15B	109.5
O4—Cu2—Cu1	86.57 (9)	H15A—C15—H15B	109.5
O8—Cu2—Cu1	84.71 (9)	C12—C15—H15C	109.5
O2—Cu2—Cu1	82.71 (9)	H15A—C15—H15C	109.5
N2—Cu2—Cu1	176.73 (9)	H15B—C15—H15C	109.5
C1—O1—Cu1	121.5 (3)	O7—C16—O8	125.4 (4)
C1—O2—Cu2	124.5 (3)	O7—C16—C17B	116.5 (4)
C6—O3—Cu1	125.2 (3)	O8—C16—C17B	118.1 (4)
C6—O4—Cu2	120.2 (3)	O7—C16—C17A	116.5 (4)
C11—O5—Cu1	121.1 (3)	O8—C16—C17A	118.1 (4)
C11—O6—Cu2	124.4 (3)	C18A—C17A—C19A	114.0 (5)
C16—O7—Cu1	124.0 (3)	C18A—C17A—C16	112.3 (4)
C16—O8—Cu2	121.8 (3)	C19A—C17A—C16	113.6 (4)
C25—N1—C21	117.7 (4)	C18A—C17A—C20A	106.2 (5)
C25—N1—Cu1	120.0 (3)	C19A—C17A—C20A	105.8 (6)
C21—N1—Cu1	121.7 (3)	C16—C17A—C20A	103.8 (4)
C26—N2—C30	118.3 (4)	C20B—C17B—C18B	123.4 (12)
C26—N2—Cu2	121.4 (3)	C20B—C17B—C16	111.2 (9)
C30—N2—Cu2	120.3 (3)	C18B—C17B—C16	113.3 (9)
O2—C1—O1	124.9 (4)	C20B—C17B—C19B	104.5 (12)
O2—C1—C2	118.5 (4)	C18B—C17B—C19B	103.3 (12)
O1—C1—C2	116.6 (4)	C16—C17B—C19B	96.6 (8)
C3—C2—C5	111.3 (5)	C17B—C18B—H18D	109.5
C3—C2—C1	107.2 (4)	C17B—C18B—H18E	109.5
C5—C2—C1	111.0 (4)	H18D—C18B—H18E	109.5
C3—C2—C4	109.5 (5)	C17B—C18B—H18F	109.5
C5—C2—C4	109.1 (5)	H18D—C18B—H18F	109.5
C1—C2—C4	108.7 (4)	H18E—C18B—H18F	109.5
C2—C3—H3A	109.5	C17B—C19B—H19D	109.5
C2—C3—H3B	109.5	C17B—C19B—H19E	109.5
H3A—C3—H3B	109.5	H19D—C19B—H19E	109.5
C2—C3—H3C	109.5	C17B—C19B—H19F	109.5
H3A—C3—H3C	109.5	H19D—C19B—H19F	109.5
H3B—C3—H3C	109.5	H19E—C19B—H19F	109.5
C2—C4—H4A	109.5	C17B—C20B—H20D	109.5
C2—C4—H4B	109.5	C17B—C20B—H20E	109.5
H4A—C4—H4B	109.5	H20D—C20B—H20E	109.5
C2—C4—H4C	109.5	C17B—C20B—H20F	109.5
H4A—C4—H4C	109.5	H20D—C20B—H20F	109.5
H4B—C4—H4C	109.5	H20E—C20B—H20F	109.5
C2—C5—H5A	109.5	N1—C21—C22	122.8 (4)
C2—C5—H5B	109.5	N1—C21—H21	118.6
H5A—C5—H5B	109.5	C22—C21—H21	118.6
C2—C5—H5C	109.5	C21—C22—C23	118.9 (4)
H5A—C5—H5C	109.5	C21—C22—H22	120.6
H5B—C5—H5C	109.5	C23—C22—H22	120.6
O3—C6—O4	125.6 (4)	C24—C23—C22	118.9 (4)
O3—C6—C7	117.1 (4)	C24—C23—H23	120.5
O4—C6—C7	117.2 (3)	C22—C23—H23	120.5
C10—C7—C8	110.0 (4)	C23—C24—C25	118.5 (4)
C10—C7—C9	109.8 (4)	C23—C24—H24	120.7
C8—C7—C9	110.2 (4)	C25—C24—H24	120.7
C10—C7—C6	111.2 (4)	N1—C25—C24	123.1 (4)
C8—C7—C6	110.3 (3)	N1—C25—H25	118.4
C9—C7—C6	105.3 (3)	C24—C25—H25	118.4
C7—C8—H8A	109.5	N2—C26—C27	123.2 (4)
C7—C8—H8B	109.5	N2—C26—H26	118.4
H8A—C8—H8B	109.5	C27—C26—H26	118.4
C7—C8—H8C	109.5	C26—C27—C28	118.3 (4)
H8A—C8—H8C	109.5	C26—C27—H27	120.9
H8B—C8—H8C	109.5	C28—C27—H27	120.9
C7—C9—H9A	109.5	C29—C28—C27	119.3 (4)
C7—C9—H9B	109.5	C29—C28—H28	120.4
H9A—C9—H9B	109.5	C27—C28—H28	120.4
C7—C9—H9C	109.5	C28—C29—C30	118.4 (4)
H9A—C9—H9C	109.5	C28—C29—H29	120.8
H9B—C9—H9C	109.5	C30—C29—H29	120.8
C7—C10—H10A	109.5	N2—C30—C29	122.6 (4)
C7—C10—H10B	109.5	N2—C30—H30	118.7
H10A—C10—H10B	109.5	C29—C30—H30	118.7

O7—Cu1—Cu2—O6	−89.67 (15)	Cu2—O2—C1—C2	−179.0 (3)
O1—Cu1—Cu2—O6	89.73 (15)	Cu1—O1—C1—O2	−4.5 (6)
O3—Cu1—Cu2—O6	178.42 (15)	Cu1—O1—C1—C2	175.5 (3)
O5—Cu1—Cu2—O6	−0.09 (15)	O2—C1—C2—C3	−109.5 (5)
O7—Cu1—Cu2—O4	89.67 (15)	O1—C1—C2—C3	70.5 (6)
O1—Cu1—Cu2—O4	−90.93 (15)	O2—C1—C2—C5	12.2 (7)
O3—Cu1—Cu2—O4	−2.25 (15)	O1—C1—C2—C5	−167.8 (5)
O5—Cu1—Cu2—O4	179.25 (14)	O2—C1—C2—C4	132.2 (5)
O7—Cu1—Cu2—O8	0.08 (14)	O1—C1—C2—C4	−47.8 (6)
O1—Cu1—Cu2—O8	179.48 (15)	Cu1—O3—C6—O4	3.0 (7)
O3—Cu1—Cu2—O8	−91.83 (15)	Cu1—O3—C6—C7	−172.9 (3)
O5—Cu1—Cu2—O8	89.66 (15)	Cu2—O4—C6—O3	−5.9 (6)
O7—Cu1—Cu2—O2	178.01 (15)	Cu2—O4—C6—C7	170.0 (3)
O1—Cu1—Cu2—O2	−2.58 (15)	O3—C6—C7—C10	−158.3 (4)
O3—Cu1—Cu2—O2	86.10 (15)	O4—C6—C7—C10	25.4 (5)
O5—Cu1—Cu2—O2	−92.41 (15)	O3—C6—C7—C8	−36.1 (5)
O3—Cu1—O1—C1	−77.8 (4)	O4—C6—C7—C8	147.7 (4)
O5—Cu1—O1—C1	89.8 (4)	O3—C6—C7—C9	82.8 (5)
N1—Cu1—O1—C1	−174.3 (4)	O4—C6—C7—C9	−93.5 (4)
Cu2—Cu1—O1—C1	4.4 (3)	Cu1—O5—C11—O6	3.2 (6)
O6—Cu2—O2—C1	−81.5 (4)	Cu1—O5—C11—C12	−174.4 (3)
O4—Cu2—O2—C1	88.6 (4)	Cu2—O6—C11—O5	−3.4 (7)
O8—Cu2—O2—C1	11.2 (9)	Cu2—O6—C11—C12	174.2 (3)
N2—Cu2—O2—C1	−174.9 (4)	O5—C11—C12—C13	−140.4 (4)
Cu1—Cu2—O2—C1	1.8 (3)	O6—C11—C12—C13	41.7 (5)
O7—Cu1—O3—C6	−83.2 (4)	O5—C11—C12—C14	100.5 (5)
O1—Cu1—O3—C6	87.0 (4)	O6—C11—C12—C14	−77.4 (5)
O5—Cu1—O3—C6	7.5 (9)	O5—C11—C12—C15	−18.6 (6)
N1—Cu1—O3—C6	−178.0 (4)	O6—C11—C12—C15	163.6 (4)
Cu2—Cu1—O3—C6	0.6 (4)	Cu1—O7—C16—O8	−0.9 (6)
O8—Cu2—O4—C6	89.4 (3)	Cu1—O7—C16—C17B	177.9 (3)
O2—Cu2—O4—C6	−78.2 (3)	Cu1—O7—C16—C17A	177.9 (3)
N2—Cu2—O4—C6	−174.8 (3)	Cu2—O8—C16—O7	1.0 (6)
Cu1—Cu2—O4—C6	4.7 (3)	Cu2—O8—C16—C17B	−177.8 (3)
O7—Cu1—O5—C11	82.7 (4)	Cu2—O8—C16—C17A	−177.8 (3)
O1—Cu1—O5—C11	−87.5 (4)	O7—C16—C17A—C18A	39.7 (6)
O3—Cu1—O5—C11	−8.2 (9)	O8—C16—C17A—C18A	−141.4 (5)
N1—Cu1—O5—C11	177.2 (4)	C17B—C16—C17A—C18A	0 (100)
Cu2—Cu1—O5—C11	−1.4 (3)	O7—C16—C17A—C19A	171.0 (5)
O8—Cu2—O6—C11	−83.1 (4)	O8—C16—C17A—C19A	−10.1 (7)
O2—Cu2—O6—C11	84.2 (4)	C17B—C16—C17A—C19A	0 (82)
N2—Cu2—O6—C11	−178.9 (4)	O7—C16—C17A—C20A	−74.6 (6)
Cu1—Cu2—O6—C11	1.7 (3)	O8—C16—C17A—C20A	104.2 (5)
O3—Cu1—O7—C16	82.3 (4)	C17B—C16—C17A—C20A	0 (100)
O5—Cu1—O7—C16	−85.1 (4)	O7—C16—C17B—C20B	−150.8 (10)
N1—Cu1—O7—C16	179.0 (3)	O8—C16—C17B—C20B	28.1 (11)
Cu2—Cu1—O7—C16	0.3 (3)	C17A—C16—C17B—C20B	0 (4)
O6—Cu2—O8—C16	83.1 (3)	O7—C16—C17B—C18B	−6.7 (11)
O4—Cu2—O8—C16	−87.2 (3)	O8—C16—C17B—C18B	172.2 (11)
O2—Cu2—O8—C16	−9.9 (9)	C17A—C16—C17B—C18B	0 (100)
N2—Cu2—O8—C16	176.2 (3)	O7—C16—C17B—C19B	100.8 (8)
Cu1—Cu2—O8—C16	−0.5 (3)	O8—C16—C17B—C19B	−80.3 (9)
O7—Cu1—N1—C25	52.8 (3)	C17A—C16—C17B—C19B	0 (100)
O1—Cu1—N1—C25	−126.9 (3)	C25—N1—C21—C22	1.2 (7)
O3—Cu1—N1—C25	144.4 (3)	Cu1—N1—C21—C22	−169.9 (4)
O5—Cu1—N1—C25	−36.8 (4)	N1—C21—C22—C23	−0.5 (8)
O7—Cu1—N1—C21	−136.4 (4)	C21—C22—C23—C24	0.1 (7)
O1—Cu1—N1—C21	44.0 (4)	C22—C23—C24—C25	−0.4 (7)
O3—Cu1—N1—C21	−44.8 (4)	C21—N1—C25—C24	−1.6 (7)
O5—Cu1—N1—C21	134.0 (3)	Cu1—N1—C25—C24	169.6 (4)
O6—Cu2—N2—C26	32.0 (3)	C23—C24—C25—N1	1.2 (7)
O4—Cu2—N2—C26	−147.4 (3)	C30—N2—C26—C27	1.2 (6)
O8—Cu2—N2—C26	−57.5 (3)	Cu2—N2—C26—C27	178.6 (3)
O2—Cu2—N2—C26	123.9 (3)	N2—C26—C27—C28	−2.1 (7)
O6—Cu2—N2—C30	−150.6 (3)	C26—C27—C28—C29	1.6 (7)
O4—Cu2—N2—C30	29.9 (3)	C27—C28—C29—C30	−0.4 (7)
O8—Cu2—N2—C30	119.9 (3)	C26—N2—C30—C29	0.1 (6)
O2—Cu2—N2—C30	−58.8 (3)	Cu2—N2—C30—C29	−177.4 (3)
Cu2—O2—C1—O1	1.0 (7)	C28—C29—C30—N2	−0.5 (7)

Hydrogen-bond geometry (Å, º) top

Cg1 and Cg2 are the centroids of the N1,C21–C25 and N2,C26–C30 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3c···Cg1ⁱ	0.98	2.90	3.609 (7)	130
C19b—H19f···Cg2ⁱⁱ	0.98	2.64	3.554 (19)	154

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

Experimental details

Crystal data
Chemical formula	[Cu₂(C₅H₉O₂)₄(C₅H₅N)₂]
M_r	689.80
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	9.4758 (6), 20.0192 (12), 18.6136 (10)
β (°)	104.515 (3)
V (Å³)	3418.3 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.29
Crystal size (mm)	0.32 × 0.26 × 0.16

Data collection
Diffractometer	Bruker SMART APEX CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.682, 0.820
No. of measured, independent and observed [I > 2σ(I)] reflections	28775, 7077, 5583
R_int	0.060
(sin θ/λ)_max (Å⁻¹)	0.628

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.058, 0.156, 1.13
No. of reflections	7077
No. of parameters	404
No. of restraints	12
H-atom treatment	H-atom parameters constrained
	w = 1/[σ²(F_o²) + (0.0532P)² + 12.7516P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	1.26, −0.75

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Selected bond lengths (Å) top

Cu1—O7	1.950 (3)	Cu2—O6	1.962 (3)
Cu1—O1	1.956 (3)	Cu2—O4	1.968 (3)
Cu1—O3	1.976 (3)	Cu2—O8	1.976 (3)
Cu1—O5	1.987 (3)	Cu2—O2	1.978 (3)
Cu1—N1	2.157 (3)	Cu2—N2	2.157 (3)

Hydrogen-bond geometry (Å, º) top

Cg1 and Cg2 are the centroids of the N1,C21–C25 and N2,C26–C30 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3c···Cg1ⁱ	0.98	2.90	3.609 (7)	130
C19b—H19f···Cg2ⁱⁱ	0.98	2.64	3.554 (19)	154

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

Footnotes

‡Additional correspondence author, e-mail: norbania@um.edu.my.

Acknowledgements

The authors thank the University of Malaya for funding this study through PPP (PS345/2010 A) and the Research University Fund (TA021/2009 A).

References

Attard, G. S. & Cullum, P. R. (1990). Liq. Cryst. 8, 299–309. CrossRef CAS Web of Science Google Scholar
Blewett, G., Esterhuysen, C., Bredenkamp, M. W. & Koch, K. R. (2006). Acta Cryst. E62, m420–m422. Web of Science CSD CrossRef IUCr Journals Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Kato, M., Jonassen, H. B., Fanning, J. C. & Cusachs, L. C. (1964). Chem. Rev. 64, 99–128. CrossRef CAS Web of Science Google Scholar
Kawata, T., Uekusa, H., Ohba, S., Furukawa, T., Tokii, T., Muto, Y. & Kato, M. (1992). Acta Cryst. B48, 253–261. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Melnik, M., Dunaj-Jurco, M. & Handlovic, M. (1984). Inorg. Chim. Acta, 86, 185–190. CSD CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43. Submitted. Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 5| May 2010| Pages m589-m590

https://doi.org/10.1107/S1600536810015060

Open

access

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)