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A new polymeric copper complex, viz. catena-poly[[[[mu]-N,N'-bis(3-amino­propyl)oxa­mid­ato-[kappa]6N,N',O:N'',N''',O']­dicopper(II)]-di-[mu]-dicyan­amido-1:1'[kappa]2N1:N5;2:2'[kappa]2N1:N5], [Cu2(C8H16N4O2)(C2N3)2]n or [Cu(oxpn)0.5{N(CN)2}]n [where H2oxpn is N,N'-bis(3-amino­propyl)­ox­amide], has been ­synthesized by the reaction of Cu(oxpn), [Cu(ClO4)2]·6H2O and NaN3. In the crystal structure, the Cu atom is five-coordinate and has a square-pyrimidal (SP) configuration. In the polymer, dicyan­amide (dca-) groups link CuII cations in a [mu]-1,5-bridging mode, generating novel ladders in which each step is composed of dimeric [Cu2(oxpn)]2+ cations. Abundant hydrogen bonds connect the polymer ladders into a two-dimensional network structure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104011011/sq1157sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104011011/sq1157Isup2.hkl
Contains datablock I

CCDC reference: 245862

Comment top

In the area of crystal engineering, much attention has been paid to new supramolecular complexes with useful properties, because they can potentially be applied to catalysis, molecular recognition and other fields (Batten & Hoskins et al., 2000; Zhang et al., 2001). Of all the supramolecular complexes, coordination polymers with special bridging ligands have become very important building blocks of ligand-bridged complexes, which offer various dimensional structures and fascinating physical properties.

Over the past few years, dca (dicyanamide, [N(CN)2]) has been chosen as a ligand in the design and synthesis of a wide variety of coordination polymers (Vangdal et al., 2002; Liang et al., 2004). The Dca ion can coordinate to metal ions in versatile patterns, such as monodentate-bonding, bidentate-bridging, tris-monodentate-bridging and four-coordination (Batten et al., 2003; Batten et al., 2000; Manson et al., 1998). In addition, N,N'-bis(coordinating groups substituted)oxamides are excellent ligands that can connect two metal ions (Ruiz et al., 1999). Some dinuclear CuII-oxpn2− [oxpn = N,N'-bis(3-aminopropyl)oxamide2−] complexes have been systhesized, for example [Cu2(oxpn)(NCO)2] (Lloret et al., 1992), [Cu2(oxpn)(NCS)2(H2O)] and [Cu2(oxpn)(N3)2(H2O)2] (Chen et al., 1994). However, all these substances are surprisingly not bridged by the quasi-halide ligands. Therefore, it is of interest to make clear whether dca can further bridge Cu2(oxpn)2+ groups to give rise to a coordination polymer. It is worth mentioning that [Cu2(oxen)(dca)2]n [oxen = N,N'-bis(2-aminoethyl)oxamido2−] shows a one-dimensional chainlike structure (Chu et al., 2003), in which the dca ion acts as a bridging ligand. In this study, we selected the oxpn2− ion to synthesize a new polymeric complex, the molecular structure of which is entirely different from that of [Cu2(oxen)(dca)2]n.

The structure of [Cu(oxpn)0.5(dca)]n is depicted in Fig. 1. Selected bond lengths and angles are listed in Table 1. The complex has a one-dimensional ladder-like molecular structure, with an oxpn-bridged dinuclear group. A centrosymmetric repeated unit is formed via the oxpn2− ion connecting two Cu2+ cations. According to the principle of low energy, oxpn2− adopts a trans conformation rather than the cis one. Therefore, the oxpn2− group chelates two CuII ions, the coordination surroundings of which are identical, i.e. coordinated by two N atoms and one O atom of the oxpn group. The bond lengths and angles of the oxpn group are similar to those in the structure reported by Chen et al. (1994). Dicyanamide binds to the Cu2+ cations in an end-to-end bridging mode through the two nitrile N atoms. The Cu2+ cation exhibits distorted square-pyramidal (SP) geometry; the basal plane is formed by one O atom and two N atoms from an oxpn2− group, and one N atom from a dca group. One N atom from another dca ligand occupies the apical position. The Cu—Nequatorial or Cu—Oequatorial bond lengths [ranging from 1.950 (3) to 1.994 (2) Å] are shorter than the Cu—Naxial bond length [2.583 (3) Å] as a result of the Jahn–Teller effect for the d9 configuration of the CuII ion in an SP environment. The cell packing of the polymeric structure is shown in Fig. 2. It can be seen that the mutually parallel dinuclear units form a novel slanted one-dimensional and dca-bridging staircase configuration. Every step is composed of a bis-chelating oxpn bridge and two Cu2+ cations. The end-to-end-linking dca groups are the stair uprights. The Cu···Cu distances across the oxpn and dca bridges are 5.246 (1) and 6.745 (1) Å, respectively. Through abundant hydrogen bonds (N—H···O and N—H···N), the one-dimensional dca-bridged ladders are linked to one another, forming a two-dimensional structure, as shown in Fig. 2.

Experimental top

Cu(oxpn) was synthesized using procedures described in the literature (Journaux et al., 1985). To a stirred purple aqueous solution (10 ml) of Cu(oxpn) (26.3 mg, 0.1 mmol) were slowly added Cu(ClO4)2·6H2O (27.1 mg, 0.1 mmol), followed by NaN3 (13.0 mg, 0.2 mmol) in water. The solution was filtered and evaporated at room temperature until violet crystals formed.

Refinement top

H atoms bound to C and N atoms were placed using the HFIX commands in SHELXL97 (Sheldrick, 1997). All H atoms were allowed for as riding atoms (C—H = 0.97 Å and N—H = 0.90 Å).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2002); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A fragment of the polymeric structure, showing the atom labeling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms have been omitted for clarity. [Symmetry codes: (i) x + 1, y, z.]
[Figure 2] Fig. 2. The packing of the two-dimensional hydrogen-bonding network of the complex. The dashed lines represent hydrogen-bonding interactions.
catena-poly[µ-dicyanamido-2':1κ2N1:N5-[[µ-N,N'-bis(3- aminopropyl)oxamidato-κ6N,N',O:N'',N''',O']dicopper(II)]-µ-dicyanamido- 2:1'κ2N1:N5] top
Crystal data top
[Cu2(C8H16N4O2)(C2N3)2]Z = 1
Mr = 459.42F(000) = 232
Triclinic, P1Dx = 1.815 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.7451 (6) ÅCell parameters from 1430 reflections
b = 7.7744 (7) Åθ = 5.1–59.6°
c = 8.0605 (7) ŵ = 2.56 mm1
α = 88.794 (2)°T = 293 K
β = 84.323 (2)°Platelet, purple
γ = 88.052 (2)°0.25 × 0.15 × 0.08 mm
V = 420.30 (6) Å3
Data collection top
Bruker SMART CCD area-detector
diffractometer
1457 independent reflections
Radiation source: fine-focus sealed tube1268 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
Detector resolution: 15×15 microns pixels mm-1θmax = 25.0°, θmin = 2.5°
ϕ and ω scansh = 58
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
k = 99
Tmin = 0.680, Tmax = 0.815l = 89
2347 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0575P)2]
where P = (Fo2 + 2Fc2)/3
1457 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 0.61 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
[Cu2(C8H16N4O2)(C2N3)2]γ = 88.052 (2)°
Mr = 459.42V = 420.30 (6) Å3
Triclinic, P1Z = 1
a = 6.7451 (6) ÅMo Kα radiation
b = 7.7744 (7) ŵ = 2.56 mm1
c = 8.0605 (7) ÅT = 293 K
α = 88.794 (2)°0.25 × 0.15 × 0.08 mm
β = 84.323 (2)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
1457 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
1268 reflections with I > 2σ(I)
Tmin = 0.680, Tmax = 0.815Rint = 0.021
2347 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.092H-atom parameters constrained
S = 1.02Δρmax = 0.61 e Å3
1457 reflectionsΔρmin = 0.30 e Å3
118 parameters
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.14911 (6)0.01279 (5)0.17231 (6)0.02874 (19)
N10.3780 (4)0.1590 (4)0.1255 (4)0.0265 (7)
O10.3087 (4)0.1506 (3)0.0209 (3)0.0284 (6)
N30.0744 (5)0.1454 (4)0.2054 (5)0.0421 (8)
C40.5220 (5)0.0896 (4)0.0298 (4)0.0249 (8)
N20.0367 (5)0.2019 (4)0.2575 (4)0.0325 (7)
H2A0.11940.22570.17840.039*
H2D0.11170.15940.34650.039*
C30.3976 (6)0.3343 (5)0.1858 (5)0.0359 (9)
H3B0.49960.39250.11430.043*
H3C0.43890.32830.29770.043*
C20.2021 (7)0.4364 (5)0.1869 (6)0.0477 (11)
H2B0.22450.55470.21410.057*
H2C0.15890.43670.07570.057*
C10.0385 (7)0.3689 (5)0.3076 (6)0.0467 (11)
H1B0.08720.35450.41640.056*
H1C0.07130.45320.31740.056*
N40.3793 (5)0.2759 (5)0.3261 (5)0.0515 (10)
C50.2221 (6)0.1978 (5)0.2653 (5)0.0349 (9)
C60.5441 (7)0.1878 (6)0.3802 (5)0.0399 (10)
N50.6954 (5)0.1242 (5)0.4259 (5)0.0504 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0217 (3)0.0262 (3)0.0367 (3)0.00267 (18)0.00639 (19)0.00399 (18)
N10.0265 (16)0.0214 (15)0.0306 (16)0.0018 (13)0.0029 (13)0.0021 (12)
O10.0224 (13)0.0254 (13)0.0362 (14)0.0050 (10)0.0050 (11)0.0018 (11)
N30.0262 (19)0.0354 (19)0.063 (2)0.0022 (15)0.0036 (17)0.0043 (17)
C40.0263 (19)0.0227 (18)0.0254 (18)0.0021 (14)0.0017 (15)0.0021 (14)
N20.0264 (17)0.0340 (17)0.0354 (18)0.0004 (14)0.0062 (14)0.0065 (14)
C30.035 (2)0.026 (2)0.046 (2)0.0044 (17)0.0040 (18)0.0068 (17)
C20.046 (3)0.026 (2)0.069 (3)0.0023 (19)0.004 (2)0.0079 (19)
C10.040 (3)0.034 (2)0.064 (3)0.0056 (19)0.009 (2)0.017 (2)
N40.033 (2)0.042 (2)0.076 (3)0.0080 (17)0.0116 (19)0.0142 (19)
C50.029 (2)0.032 (2)0.044 (2)0.0009 (18)0.0050 (19)0.0014 (18)
C60.035 (3)0.050 (3)0.036 (2)0.013 (2)0.005 (2)0.0090 (19)
N50.032 (2)0.072 (3)0.045 (2)0.0047 (19)0.0068 (17)0.0000 (19)
Geometric parameters (Å, º) top
Cu1—N11.951 (3)N2—H2D0.9000
Cu1—N31.972 (3)C3—C21.515 (6)
Cu1—N21.987 (3)C3—H3B0.9700
Cu1—O11.994 (3)C3—H3C0.9700
Cu1—N5i2.583 (3)C2—C11.498 (6)
N1—C41.289 (5)C2—H2B0.9700
N1—C31.471 (5)C2—H2C0.9700
O1—C4ii1.278 (4)C1—H1B0.9700
N3—C51.147 (5)C1—H1C0.9700
C4—O1ii1.278 (4)N4—C51.289 (5)
C4—C4ii1.532 (7)N4—C61.327 (6)
N2—C11.487 (5)C6—N51.149 (5)
N2—H2A0.9000
N1—Cu1—N3175.76 (13)N1—C3—H3B109.4
N1—Cu1—N294.99 (12)C2—C3—H3B109.4
N3—Cu1—N288.59 (14)N1—C3—H3C109.4
N1—Cu1—O183.98 (11)C2—C3—H3C109.4
N3—Cu1—O191.92 (13)H3B—C3—H3C108.0
N2—Cu1—O1162.46 (12)C1—C2—C3114.2 (4)
C4—N1—C3119.4 (3)C1—C2—H2B108.7
C4—N1—Cu1113.9 (2)C3—C2—H2B108.7
C3—N1—Cu1126.7 (3)C1—C2—H2C108.7
C4ii—O1—Cu1111.0 (2)C3—C2—H2C108.7
C5—N3—Cu1157.0 (4)H2B—C2—H2C107.6
O1ii—C4—N1128.9 (3)N2—C1—C2113.2 (4)
O1ii—C4—C4ii117.3 (4)N2—C1—H1B108.9
N1—C4—C4ii113.8 (4)C2—C1—H1B108.9
C1—N2—Cu1121.3 (3)N2—C1—H1C108.9
C1—N2—H2A107.0C2—C1—H1C108.9
Cu1—N2—H2A107.0H1B—C1—H1C107.7
C1—N2—H2D107.0C5—N4—C6120.8 (4)
Cu1—N2—H2D107.0N3—C5—N4172.6 (4)
H2A—N2—H2D106.7N5—C6—N4174.2 (5)
N1—C3—C2111.0 (3)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y, z.

Experimental details

Crystal data
Chemical formula[Cu2(C8H16N4O2)(C2N3)2]
Mr459.42
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.7451 (6), 7.7744 (7), 8.0605 (7)
α, β, γ (°)88.794 (2), 84.323 (2), 88.052 (2)
V3)420.30 (6)
Z1
Radiation typeMo Kα
µ (mm1)2.56
Crystal size (mm)0.25 × 0.15 × 0.08
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2000)
Tmin, Tmax0.680, 0.815
No. of measured, independent and
observed [I > 2σ(I)] reflections
2347, 1457, 1268
Rint0.021
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.092, 1.02
No. of reflections1457
No. of parameters118
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.61, 0.30

Computer programs: SMART (Bruker, 2000), SMART, SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2002), SHELXL97.

Selected geometric parameters (Å, º) top
Cu1—N11.951 (3)N3—C51.147 (5)
Cu1—N31.972 (3)N4—C51.289 (5)
Cu1—N21.987 (3)N4—C61.327 (6)
Cu1—O11.994 (3)C6—N51.149 (5)
Cu1—N5i2.583 (3)
N1—Cu1—N3175.76 (13)N2—Cu1—O1162.46 (12)
N1—Cu1—N294.99 (12)C5—N3—Cu1157.0 (4)
N3—Cu1—N288.59 (14)C5—N4—C6120.8 (4)
N1—Cu1—O183.98 (11)N3—C5—N4172.6 (4)
N3—Cu1—O191.92 (13)N5—C6—N4174.2 (5)
Symmetry code: (i) x+1, y, z.
 

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