supplementary materials


ng5345 scheme

Acta Cryst. (2013). E69, m690    [ doi:10.1107/S160053681303184X ]

catena-Poly[[tetra-[mu]-formato-[kappa]8O:O'-dicopper(II)]-[mu]-hexa­methyl­ene­tetra­mine-[kappa]2N1:N5]

J. Cao, Z. Huang, C. Cao, C. Cheng and C. Sun

Abstract top

In the title polymeric compound, [Cu2(HCO2)4(C6H12N4)]n, the CuII atom is five-coordinated in a square-pyramidal geometry that is defined by four O atoms from four formate ligands and one N atom from a hexa­methyl­ene­tetra­mine ligand. The two CuII atoms are separated by 2.6850 (7) Å, and together with the four formate ligands they form a paddle-wheel unit. The hexa­mine ligand uses only two of its four N atoms to link Cu2 cluster units, affording a zigzag chain running along the b-axis direction. The hexa­mine ligand lies on a mirror plane.

Comment top

The design and synthesis of metal-organic complexes or coordination polymers is a rapidly developing field in coordination and supramolecular chemistry during the past decades. Hexamethylenetetramine (hmt), also known as hexamine or urotropine, can be considered as one such simple heterocyclic compound with a cagelike structure which,owing to its high solubility in water and polar organic solvents, has found a broad variety of applications (Dreyfors et al., 1989). With regard to coordination chemistry, hmt is a versatile ligand capable of adopting different coordination modes that span from the terminal monodentate to bridging bi-, tri- and tetradentate modes. The well known [Cu2(carboxylate)4] units with four bridging carboxylate ligands in the familiar η1:η1:µ coordination mode have accessible apical coordination sites and are ideally suited to serve as a metal-based linear spacer (Konar et al. 2003; Chiari et al., 1988; Wu et al., 2004; Sun et al., 2009). To date, the title copper(II) carboxylate complex, represents an exception, as only few formate copper(II) complexes have been studied.

The crystal structure of the title complex, which is isostructural with its copper analog (Wang et al., 2002), is built of hexamethylenetetramine molecules and paddle-wheel dicopper units, both of which occupy special positions. The structure of the centrosymmetric [Cu2(HCO2)4] moiety is shown in Fig. 1. The coordination geometry of the Cu atom may be described as a square pyramid, formed by four formatee O atoms and the N atom of the hexamine . The four basal Cu—O distances fall in the range from 1.963 (2) to 1.978 (2) Å. The central hmt has mirror symmetry, and therefore there is only one independent CuII atom in the asymmetric unit. The Cu—Cu distance within the [Cu2(HCO2)4] unit is 2.6850 (7) Å indicating a strong interaction. The axial Cu(1)—N(1) distance is 2.212 (2) Å. The hexamine ligand uses only two of its four N atoms to link adjacent paddle-wheel Cu2-cluster units, to afford a zigzag chain running along the b axis of the unit cell (Fig. 2).

Related literature top

For background to hexamine chemistry, see: Dreyfors et al. (1989); Kirillov (2011). For hexamine as a bridging ligand, see: Pickardt (1981); Konar et al. (2003); Wang et al. (2002). For paddle-wheel Cu2-cluster units, see: Konar et al. (2003); Chiari et al. (1988); Wu & Wang (2004); Sun et al. (2009).

Experimental top

The title compound was synthesized by the following method. Copper(II) formate tetrahydrate (0.015 g, 0.1 mmol) was dissolved in 20 ml me thanol to obtain solution A. Hexamine (0.007 g, 0.05 mmol) was dissolved in 10 ml methanol to obtain solution B. Solution B was layered carefully on solution A, and the tube was sealed and stored in room temperature. Green block crystals were obtained after two weeks. Analysis calculated for C5H8CuN2O4: C 26.85, H 3.60, N 12.52%; found: C 26.66, H 3.82, N 12.65%.

Refinement top

All non-hydrogen atoms were refined anisotropically. The H atoms of formate were positioned geometrically and allowed to ride on their parent atoms, with C–H = 0.95 Å and Uiso(H) = 1.2Ueq(C). The H atoms of hexamethylenetetramine the were placed in geometrically idealized positions and refined as riding atoms, with C–H(CH2) = 0.99 Å and Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of [Cu2(HCO2)4(C6H12N4)]n showing the atomic dlabelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. The zigzag chain in the crystal packing structure of [Cu2(HCO2)4(C6H12N4)]n along b the axis.
catena-Poly[[tetra-µ-formato-κ8O:O'-dicopper(II)]-µ-hexamethylenetetramine-κ2N1:N5] top
Crystal data top
[Cu2(CHO2)4(C6H12N4)]F(000) = 904
Mr = 447.36Dx = 2.022 Mg m3
Dm = 2.022 Mg m3
Dm measured by not measured
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 1680 reflections
a = 13.1252 (19) Åθ = 2.4–26.4°
b = 17.281 (3) ŵ = 2.95 mm1
c = 6.4777 (9) ÅT = 103 K
V = 1469.3 (4) Å3Block, green
Z = 40.26 × 0.24 × 0.18 mm
Data collection top
Bruker SMART APEX area-detector
diffractometer
1550 independent reflections
Radiation source: fine-focus sealed tube1345 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
Detector resolution: 16.0143 pixels mm-1θmax = 26.4°, θmin = 2.4°
ω scansh = 716
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
k = 1621
Tmin = 0.469, Tmax = 0.588l = 88
5203 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.028 w = 1/[σ2(Fo2) + (0.0488P)2 + 0.5436P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.077(Δ/σ)max = 0.001
S = 1.04Δρmax = 0.69 e Å3
1550 reflectionsΔρmin = 0.71 e Å3
115 parameters
Crystal data top
[Cu2(CHO2)4(C6H12N4)]V = 1469.3 (4) Å3
Mr = 447.36Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 13.1252 (19) ŵ = 2.95 mm1
b = 17.281 (3) ÅT = 103 K
c = 6.4777 (9) Å0.26 × 0.24 × 0.18 mm
Data collection top
Bruker SMART APEX area-detector
diffractometer
1550 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1345 reflections with I > 2σ(I)
Tmin = 0.469, Tmax = 0.588Rint = 0.021
5203 measured reflectionsθmax = 26.4°
Refinement top
R[F2 > 2σ(F2)] = 0.028H-atom parameters constrained
wR(F2) = 0.077Δρmax = 0.69 e Å3
S = 1.04Δρmin = 0.71 e Å3
1550 reflectionsAbsolute structure: ?
115 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
Special details top

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

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cu10.03147 (2)0.569254 (15)0.06885 (4)0.01482 (13)
N10.09051 (15)0.67876 (11)0.1987 (3)0.0167 (4)
C60.2292 (3)0.75000.4773 (7)0.0376 (11)
H6A0.26070.79630.54070.045*0.50
H6B0.26070.70370.54070.045*0.50
O10.06061 (14)0.61313 (10)0.1393 (3)0.0243 (4)
O20.11320 (13)0.49698 (10)0.2546 (3)0.0222 (4)
O30.08446 (14)0.55920 (9)0.2587 (3)0.0229 (4)
O40.13726 (14)0.44265 (9)0.1462 (3)0.0228 (4)
C10.11161 (19)0.56950 (13)0.2535 (4)0.0189 (5)
H10.15440.59440.35150.023*
C20.14152 (18)0.50082 (13)0.2619 (4)0.0186 (5)
H20.19380.50070.36340.022*
C30.20300 (19)0.68165 (14)0.1630 (4)0.0256 (6)
H3A0.23470.63460.22220.031*
H3B0.21640.68170.01260.031*
C40.0729 (2)0.68132 (15)0.4251 (4)0.0256 (6)
H4A0.00140.68130.45200.031*
H4B0.10200.63420.48890.031*
C50.0455 (3)0.75000.1069 (5)0.0164 (7)
H5A0.02900.75000.13010.020*
H5B0.05760.75000.04400.020*
N20.2502 (3)0.75000.2553 (6)0.0306 (8)
N30.1187 (3)0.75000.5219 (5)0.0299 (8)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.01667 (19)0.01185 (19)0.01595 (19)0.00041 (10)0.00034 (10)0.00042 (10)
N10.0205 (10)0.0106 (9)0.0191 (10)0.0003 (8)0.0004 (8)0.0002 (8)
C60.047 (3)0.0180 (19)0.048 (3)0.0000.028 (2)0.000
O10.0307 (10)0.0168 (9)0.0253 (9)0.0018 (7)0.0092 (8)0.0001 (7)
O20.0245 (9)0.0181 (9)0.0240 (9)0.0009 (7)0.0066 (7)0.0015 (7)
O30.0232 (10)0.0207 (9)0.0248 (10)0.0027 (7)0.0062 (7)0.0043 (7)
O40.0253 (9)0.0197 (9)0.0234 (9)0.0044 (7)0.0056 (8)0.0033 (7)
C10.0182 (12)0.0205 (12)0.0181 (13)0.0038 (9)0.0019 (9)0.0032 (9)
C20.0171 (12)0.0195 (12)0.0192 (12)0.0037 (10)0.0002 (9)0.0018 (9)
C30.0215 (13)0.0151 (12)0.0401 (16)0.0018 (10)0.0030 (11)0.0002 (11)
C40.0407 (16)0.0161 (13)0.0199 (13)0.0014 (12)0.0026 (11)0.0029 (9)
C50.0196 (17)0.0127 (16)0.0169 (16)0.0000.0021 (13)0.000
N20.0226 (16)0.0167 (15)0.052 (2)0.0000.0107 (14)0.000
N30.053 (2)0.0145 (15)0.0219 (16)0.0000.0136 (15)0.000
Geometric parameters (Å, º) top
Cu1—O11.9632 (17)O2—Cu1i1.9769 (16)
Cu1—O31.9640 (18)O3—C21.257 (3)
Cu1—O2i1.9769 (17)O4—C21.255 (3)
Cu1—O4i1.9777 (18)C2—H20.950
Cu1—N12.2112 (19)O4—Cu1i1.9777 (18)
Cu1—Cu1i2.6848 (6)C3—N21.461 (3)
N1—C41.485 (3)C3—H3A0.990
N1—C51.489 (3)C3—H3B0.990
N1—C31.495 (3)C4—N31.471 (3)
C6—N21.464 (6)C4—H4A0.991
C6—N31.479 (6)C4—H4B0.990
C6—H6A0.990C5—N1ii1.489 (3)
C6—H6B0.990C5—H5A0.989
O1—C11.251 (3)C5—H5B0.990
O2—C11.253 (3)N2—C3ii1.461 (3)
C1—H10.951N3—C4ii1.471 (3)
O1—Cu1—O389.26 (8)H5B—C5—N1109.30
O1—Cu1—O2i167.34 (7)C4—N1—Cu1110.27 (15)
H1—C1—O1116.00H4A—C4—N3109.13
H1—C1—O2116.04H4B—C4—N3109.16
O3—Cu1—O2i89.33 (7)C5—N1—Cu1114.62 (15)
O1—Cu1—O4i89.34 (8)C3—N1—Cu1108.41 (14)
O3—Cu1—O4i167.36 (7)N2—C6—N3112.1 (3)
O2i—Cu1—O4i89.28 (8)C1—O1—Cu1120.20 (15)
H2—C2—O3116.33C1—O2—Cu1i124.51 (16)
H2—C2—O4116.33C2—O3—Cu1122.90 (15)
O1—Cu1—N198.43 (7)C2—O4—Cu1i122.36 (16)
O3—Cu1—N196.26 (7)H3A—C3—H3B107.88
O2i—Cu1—N194.24 (7)H4A—C4—H4B107.83
O4i—Cu1—N196.37 (7)H5B—C5—H5A107.97
O1—Cu1—Cu1i85.79 (5)O1—C1—O2127.9 (2)
O3—Cu1—Cu1i83.73 (5)O4—C2—O3127.3 (2)
O2i—Cu1—Cu1i81.54 (5)N2—C3—N1112.5 (2)
O4i—Cu1—Cu1i83.64 (5)N3—C4—N1112.4 (2)
N1—Cu1—Cu1i175.78 (5)N1—C5—N1ii111.5 (3)
H3A—C3—N1109.11C3—N2—C3ii107.9 (3)
H3B—C3—N1109.13C3—N2—C6108.8 (2)
H3A—C3—N2109.08H6A—C6—N2109.20
H4B—C4—N3109.06H6B—C6—N2109.20
C4—N1—C5107.9 (2)H6A—C6—N3109.18
C4—N1—C3107.8 (2)H6B—C6—N3109.18
H4A—C4—N1109.08C3ii—N2—C6108.8 (2)
H4B—C4—N1109.13C4ii—N3—C4107.6 (3)
C5—N1—C3107.6 (2)C4ii—N3—C6108.5 (2)
H5A—C5—N1109.35C4—N3—C6108.5 (2)
Symmetry codes: (i) x, y+1, z; (ii) x, y+3/2, z.

Experimental details

Crystal data
Chemical formula[Cu2(CHO2)4(C6H12N4)]
Mr447.36
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)103
a, b, c (Å)13.1252 (19), 17.281 (3), 6.4777 (9)
V3)1469.3 (4)
Z4
Radiation typeMo Kα
µ (mm1)2.95
Crystal size (mm)0.26 × 0.24 × 0.18
Data collection
DiffractometerBruker SMART APEX area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.469, 0.588
No. of measured, independent and
observed [I > 2σ(I)] reflections
5203, 1550, 1345
Rint0.021
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.028, 0.077, 1.04
No. of reflections1550
No. of parameters115
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.69, 0.71

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements top

This work was partially supported by the Mid-aged and Young Foundation of Qinghai University (2012-QGT-2).

references
References top

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Dreyfors, J. M., Jones, S. B. & Sayed, Y. (1989). Am. Ind. Hyg. Assoc. J. 50, 579–585.

Kirillov, A. M. (2011). Coord. Chem. Rev. 255, 1603–1622.

Konar, S., Mukherjee, P. S. M., Drew, G. B., Ribas, J. & Chaudhuri, N. R. (2003). Inorg. Chem. 42, 2545–2552.

Pickardt, J. (1981). Acta Cryst. B37, 1753–1756.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

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Wu, B. & Wang, G. (2004). Acta Cryst. E60, m1764–m1765.