Download citation
Download citation
link to html
The novel title polymeric copper(II) complex, {Na2[Cu3-(CHO2)8]}n, consists of sodium cations and infinite anionic chains, in which neutral dinuclear [Cu2(O2CH)4] moieties alternate with dianionic [Cu(O2CH)4]2− units. Both metal-containing moieties are located on crystallographic inversion centers. The synsyn bridging configuration between the mononuclear and dinuclear components yields a structure that is significantly more dense than the structures previously reported for mononuclear–dinuclear copper(II) carboxyl­ates with synanti or anti–anti bridging modes.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106001636/fa1173sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270106001636/fa1173Isup2.hkl
Contains datablock I

CCDC reference: 202837

Comment top

Although a large number of dimeric copper(II) carboxylate complexes of the paddle wheel cage type have been structurally characterized, only nine structures of formate derivatives are known (Bernard et al., 1979; Bukowska-Strzyzewska, 1966; Uekusa et al., 1989; Yamanaka et al., 1991; Goodgame et al., 1969; Cejudo et al., 2002; Sapina et al., 1994). In only one of these (Bukowska-Strzyzewska, 1966) are dimeric copper(II) formate units found to be linked into a polymeric structure. Not only is the title compound a new example of such an extended structure, it is also the first CuII formate that contains both mono- and dinuclear carboxylate copper(II) units. A view along the a axis of the cell is given in Fig. 1. Infinite chains, formed by [Cu2(O2CH)4] dimers bridged by [Cu(O2CH)4]2− anions, propagate along the [011] direction. The charge is balanced by sodium cations, located between the polymeric chains. Fig. 2 shows the coordination of formate ligands around the metal ions. The dimeric unit is centrosymmetric with four bidentate formate syn-syn bridges between Cu1 atoms, which are in a 4 + 1 environment. The basal coordination of atom Cu1 is formed by four coplanar O atoms from two pairs of symmetry-related formate anions with an average Cu—Obasal distance of 1.968 Å. The apical distance, Cu1—O42, is significantly longer [2.104 (5) Å]. The distortion of the square-pyramidal arrangement of the O atoms around atom Cu1 is very small; τ is 0.005 (Addison et al., 1984). The Cu···Cu separation within the dimer is 2.620 (1) Å. This and the bond distances in the dimer are comparable to those in other dinuclear copper formates (Bernard et al., 1979; Bukowska-Strzyzewska, 1966; Uekusa et al., 1989; Yamanaka et al., 1991; Goodgame et al., 1969; Cejudo et al., 2002; Sapina et al., 1994). The apical formate ligand is coordinated through atom O41 to the second copper ion, Cu2, thus bridging dimeric and monomeric units to form the polymeric chain. The coordination polyhedron of atom Cu2, which is also located on an inversion centre, is an axially elongated octahedron of O atoms from the three pairs of symmetry-related formate anions. This coordination may be viewed as 4 + 2, which is quite typical and expected for six-coordinate CuII in view of Jahn–Teller effects (Hathaway, 1987). The equatorial O atoms O41, from the bridging formate, and O31, from the only formate ligand that is not coordinated to Cu1, are closer than 2 Å to Cu2. Two O atoms, O11 and its symmetry equivalent, which lie at a significantly longer distance [2.492 (5) Å], are part of the bridging formate groups from the dimeric [Cu2(O2CH)4] unit, and make a second bridge between the monomeric and dimeric units. This additional bridge is possible because the first mode of bridging between dimer and monomer (through bonds Cu1—O42 and Cu2—O41) is syn--syn. A synanti or anti–anti mode of bridging could not have brought the units close enough for such additional stabilization. The consequence of this new mode of bridging is a significantly higher density (2.275 Mg m−3), as compared with the densities of analogous copper(II) structures (Wang et al., 2000; Valigura et al., 1986; Escuer et al., 1999; Hokelek et al., 1998; Zubkowski et al., 1997; Chiari et al., 1993; Valo & Nasakkala, 1994; Petrenko & Kiosse, 2000; Kani et al., 2000; Neels et al., 1995; Dunaj-Jurco et al., 1995) with synanti or anti–anti bridging modes between mono- and dinuclear units. In the latter, the densities are lower than 1.79 Mg m−3. For instance, in K2n[{Cu2(O2CCH3)4}{Cu(O2CCH3)4}]n (Valo & Nasakkala, 1994), whose formula is very similar to that of the title compound, but in which the bridging mode between monomeric and dimeric units is synanti, the density is only 1.558 Mg m−3. Also, the intra-chain distance beween atoms Cu1 and Cu2 in K2n[{Cu2(O2CCH3)4}{Cu(O2CCH3)4}]n is 5.088 (1) Å. The corresponding distance in the title compound is 3.7103 (7) Å. On the other hand, the shortest inter-chain distances between copper ions are similar in the two structures, viz. 6.503 (1) Å in K2n[{Cu2(O2CCH3)4}{Cu(O2CCH3)4}]n and 6.526 (1) Å in the title compound.

The synsyn bridging mode between dimeric and monomeric units is novel among copper carboxylates and is probably sterically feasible only for formates. This notion is supported by the fact that such a structural motif (within metal carboxylates) has only been observed in one structure [Cr3(O2CH)6·2H2O], also a formate compound (Cotton et al., 1978).

The sodium cations are surrounded by seven formate O atoms at distances ranging from 2.319 (9) to 2.699 (9) Å. The sodium coordination polyhedra are connected through O42···O42(-x + 1,-y,-z) and O32···O32(-x + 1,-y + 1,-z) edges into infinite chains, which run along the b axis.

Experimental top

Sodium formate was prepared by evaporating an equimolar aqueous solution of methanoic acid and sodium hydroxide to dryness. Sodium formate (1.09 g, 16 mmol) was dissolved with stirring in a mixture of methanol (50 ml) and distilled water (2 ml) acidified by a few drops of methanoic acid. The solution obtained was filtered into a solution of CuCl2·2H2O (0.68 g, 4.0 mmol) in acidified methanol (10 ml). The solution was left to stand at 278 K for 24 h. The green crystalline product was filtered and dried over KOH in a desiccator overnight. The average yield of the synthesis was 87%. The same product was obtained in lower yields using a similar procedure if Cu(NO3)2·3H2O or anhydrous copper formate (α form) were used as starting materials. All samples were checked by powder X-ray diffraction, which gave d spacings and relative intensities in agreement with the values calculated from the single-crystal structure analysis. Single crystals, stable in air and suitable for structural analysis, were obtained by the above procedure using more dilute solutions.

Refinement top

The positions of all H atoms were obtained from the difference Fourier map. Full-matrix least-squares refinement on F2 was employed with anisotropic displacement parameters for all non-H and with isotropic displacement parameters for H atoms. The exception was the H atom bonded to C1 whose isotropic displacement parameter was set to be equal to 1.2Ueq(C1). A Regina weighting scheme (Wang & Robertson, 1985) using a normal equation of second order was applied for individual reflections so that w = A(0,0) + A(1,0) V(F) + A(0,1) V(S) + A(2,0) V(F)2 + A(0,2) V(S)2 + A(1,1) V(F)V(S), where V(F) = F2obs/F2obs(max), F2obs(max) = 12638 and V(S) = (sinθ/λ)/[(sinθ/λ)(max)], (sinθ/λ)(max) = 0.6497. The parameters are A(0,0) = 3200.667, A(1,0) = 22.59881, A(0,1) = −2802.914, A(2,0) = −0.0017726, A(1,1) = −14.87134, A(0,2) = −7847.764. The highest peak in the final difference Fourier map is located between Na and O32 [1.723 (3) Å from Na and 1.255 (7) Å from O32] and the deepest hole between Cu1 and O32 [1.2329 (8) Å from Cu1 and 1.030 (8) Å from O22].

Computing details top

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: Xtal3.6 (Hall et al., 1999); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: Xtal3.6 and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The packing of the title compound viewed along the a axis.
[Figure 2] Fig. 2. An ORTEP-3 drawing (Farrugia, 1997), with ellipsoids drawn at the 50% probability level. Dashed lines depict the additional connections between binuclear and mononuclear formate copper(II) units. [Symmetry codes: (i) −x + 2, −y, −z; (ii) −x + 1, −y, −z; (iii) −x + 2, −y + 1, −z + 1; iv: (1 − x,1 − y,-z), v: (−1 + x,y,z)]
catena-Poly[disodium [[diformatotricopper(II)]-di-µ3-formato-tetra-µ2-formato]] top
Crystal data top
Na2[Cu3(CHO2)8]Z = 1
Mr = 596.76F(000) = 293
Triclinic, P1Dx = 2.275 Mg m3
Hall symbol: -p 1Mo Kα radiation, λ = 0.71073 Å
a = 7.6594 (2) ÅCell parameters from 1672 reflections
b = 7.7717 (1) Åθ = 2.9–27.5°
c = 8.7972 (2) ŵ = 3.76 mm1
α = 113.248 (1)°T = 293 K
β = 108.653 (1)°Prism, green
γ = 97.495 (1)°0.12 × 0.10 × 0.07 mm
V = 435.61 (2) Å3
Data collection top
Nonius KappaCCD
diffractometer
1966 independent reflections
Radiation source: xray tube1775 reflections with F2 > 2.00 sig(F2)
Graphite monochromatorRint = 0.038
ϕ and ω scansθmax = 27.5°, θmin = 2.9°
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor 1997)
h = 99
Tmin = 0.64, Tmax = 0.77k = 1010
5090 measured reflectionsl = 911
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.052H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.152
S = 1.04(Δ/σ)max = 0.001
1775 reflectionsΔρmax = 1.77 e Å3
148 parametersΔρmin = 1.72 e Å3
Crystal data top
Na2[Cu3(CHO2)8]γ = 97.495 (1)°
Mr = 596.76V = 435.61 (2) Å3
Triclinic, P1Z = 1
a = 7.6594 (2) ÅMo Kα radiation
b = 7.7717 (1) ŵ = 3.76 mm1
c = 8.7972 (2) ÅT = 293 K
α = 113.248 (1)°0.12 × 0.10 × 0.07 mm
β = 108.653 (1)°
Data collection top
Nonius KappaCCD
diffractometer
1966 independent reflections
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor 1997)
1775 reflections with F2 > 2.00 sig(F2)
Tmin = 0.64, Tmax = 0.77Rint = 0.038
5090 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.052148 parameters
wR(F2) = 0.152H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 1.77 e Å3
1775 reflectionsΔρmin = 1.72 e Å3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.88612 (9)0.03853 (11)0.08489 (9)0.0203 (3)
Cu21.000000.500000.500000.0212 (3)
O111.0913 (7)0.2859 (7)0.2594 (6)0.0285 (14)
O121.2858 (7)0.2225 (8)0.1151 (7)0.0343 (16)
O210.7873 (7)0.1621 (8)0.0680 (7)0.0302 (16)
O220.9812 (9)0.0929 (9)0.2146 (8)0.0350 (18)
O310.7852 (8)0.5103 (8)0.3168 (7)0.0329 (16)
O320.5832 (9)0.6577 (11)0.2167 (10)0.047 (2)
O410.8186 (7)0.2809 (7)0.4857 (6)0.0280 (14)
O420.6732 (6)0.0676 (7)0.1886 (6)0.0249 (13)
C11.2433 (9)0.3288 (10)0.2389 (9)0.0285 (18)
C20.8550 (11)0.1669 (12)0.1828 (9)0.031 (2)
C30.7373 (10)0.6629 (11)0.3241 (10)0.030 (2)
C40.6906 (9)0.1344 (10)0.3499 (9)0.0269 (18)
Na0.5425 (4)0.2744 (4)0.0234 (4)0.0259 (8)
H11.346 (12)0.453 (10)0.323 (13)0.03400*
H20.807 (15)0.248 (16)0.237 (14)0.03 (2)*
H30.876 (11)0.774 (12)0.410 (11)0.011 (16)*
H40.571 (14)0.089 (15)0.378 (13)0.02 (2)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0195 (3)0.0216 (4)0.0193 (3)0.0066 (3)0.0094 (3)0.0076 (3)
Cu20.0219 (4)0.0182 (5)0.0177 (4)0.0041 (3)0.0032 (3)0.0073 (4)
O110.027 (2)0.023 (2)0.024 (2)0.0014 (17)0.0109 (17)0.0014 (19)
O120.030 (2)0.028 (2)0.032 (2)0.0003 (19)0.017 (2)0.001 (2)
O210.033 (2)0.038 (3)0.033 (2)0.020 (2)0.017 (2)0.023 (2)
O220.044 (3)0.042 (3)0.037 (3)0.022 (2)0.024 (2)0.027 (2)
O310.032 (2)0.025 (2)0.026 (2)0.0064 (18)0.0001 (18)0.0085 (18)
O320.039 (3)0.051 (4)0.055 (4)0.014 (3)0.007 (3)0.039 (3)
O410.031 (2)0.024 (2)0.021 (2)0.0011 (17)0.0063 (17)0.0088 (18)
O420.0238 (18)0.027 (2)0.0222 (19)0.0087 (16)0.0119 (16)0.0081 (18)
C10.021 (2)0.026 (3)0.026 (3)0.002 (2)0.009 (2)0.002 (2)
C20.041 (3)0.038 (4)0.028 (3)0.020 (3)0.015 (3)0.024 (3)
C30.032 (3)0.028 (3)0.032 (3)0.011 (2)0.009 (3)0.018 (3)
C40.024 (2)0.024 (3)0.024 (3)0.001 (2)0.009 (2)0.006 (2)
Na0.0239 (10)0.0267 (12)0.0249 (11)0.0076 (9)0.0094 (10)0.0103 (10)
Geometric parameters (Å, º) top
Cu1—O111.965 (5)Na—O32iv2.319 (9)
Cu1—O211.965 (6)O11—C11.257 (9)
Cu1—O422.104 (5)O12—C11.250 (9)
Cu1—O12i1.987 (6)O21—C21.285 (10)
Cu1—O22i1.956 (7)O22—C21.239 (12)
Cu2—O112.492 (5)O31—C31.270 (11)
Cu2—O311.937 (6)O32—C31.238 (11)
Cu2—O411.987 (6)O41—C41.253 (9)
Na—O212.400 (7)O42—C41.257 (8)
Na—O312.405 (6)C1—H10.98 (10)
Na—O322.699 (9)C2—H20.97 (13)
Na—O422.652 (6)C3—H31.09 (9)
Na—O12ii2.397 (7)C4—H41.07 (11)
Na—O42iii2.499 (6)
O11—Cu1—O2188.9 (2)O32iv—Na—O42iii86.2 (3)
O11—Cu1—O42101.9 (2)Cu1—O11—Cu2112.2 (2)
O11—Cu1—O12i168.7 (2)Cu1—O11—C1121.4 (5)
O11—Cu1—O22i89.7 (3)Cu2—O11—C1126.3 (5)
O21—Cu1—O4293.6 (2)Navi—O12—C1133.5 (5)
O12i—Cu1—O2190.3 (2)Cu1i—O12—C1123.9 (5)
O21—Cu1—O22i169.0 (3)Cu1i—O12—Navi102.1 (2)
O12i—Cu1—O4289.4 (2)Cu1—O21—Na102.8 (2)
O22i—Cu1—O4297.4 (3)Cu1—O21—C2121.6 (6)
O12i—Cu1—O22i88.9 (3)Na—O21—C2135.7 (6)
O11—Cu2—O3189.8 (2)Cu1i—O22—C2123.6 (6)
O11—Cu2—O4195.1 (2)Cu2—O31—Na135.0 (3)
O11—Cu2—O31v90.2 (2)Cu2—O31—C3126.1 (5)
O11—Cu2—O41v85.0 (2)Na—O31—C398.8 (5)
O31—Cu2—O4187.9 (2)Na—O32—C385.9 (6)
O31—Cu2—O41v92.1 (2)Na—O32—Naiv98.2 (3)
O21—Na—O3190.3 (2)Naiv—O32—C3142.0 (7)
O21—Na—O32122.5 (3)Cu2—O41—C4129.9 (5)
O21—Na—O4271.7 (2)Cu1—O42—Na91.3 (2)
O12ii—Na—O21149.3 (3)Cu1—O42—C4129.7 (5)
O21—Na—O42iii86.3 (2)Cu1—O42—Naiii95.6 (2)
O21—Na—O32iv93.6 (3)Na—O42—C4115.0 (5)
O31—Na—O3250.8 (2)Na—O42—Naiii104.11 (19)
O31—Na—O4274.4 (2)Naiii—O42—C4116.2 (5)
O12ii—Na—O3197.7 (2)O11—C1—O12125.9 (7)
O31—Na—O42iii149.7 (2)O21—C2—O22125.8 (8)
O31—Na—O32iv124.1 (3)O31—C3—O32123.2 (8)
O32—Na—O42120.7 (2)O41—C4—O42127.2 (7)
O12ii—Na—O3284.2 (2)O11—C1—H1123 (6)
O32—Na—O42iii149.2 (2)O12—C1—H1112 (6)
O32—Na—O32iv81.8 (3)O21—C2—H2113 (7)
O12ii—Na—O4281.9 (2)O22—C2—H2121 (7)
O42—Na—O42iii75.89 (19)O31—C3—H3101 (5)
O32iv—Na—O42157.3 (3)O32—C3—H3134 (5)
O12ii—Na—O42iii72.0 (2)O41—C4—H4112 (5)
O12ii—Na—O32iv105.9 (3)O42—C4—H4120 (5)
Symmetry codes: (i) x+2, y, z; (ii) x1, y, z; (iii) x+1, y, z; (iv) x+1, y+1, z; (v) x+2, y+1, z+1; (vi) x+1, y, z.

Experimental details

Crystal data
Chemical formulaNa2[Cu3(CHO2)8]
Mr596.76
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)7.6594 (2), 7.7717 (1), 8.7972 (2)
α, β, γ (°)113.248 (1), 108.653 (1), 97.495 (1)
V3)435.61 (2)
Z1
Radiation typeMo Kα
µ (mm1)3.76
Crystal size (mm)0.12 × 0.10 × 0.07
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(DENZO-SMN; Otwinowski & Minor 1997)
Tmin, Tmax0.64, 0.77
No. of measured, independent and
observed [F2 > 2.00 sig(F2)] reflections
5090, 1966, 1775
Rint0.038
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.152, 1.04
No. of reflections1775
No. of parameters148
No. of restraints?
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)1.77, 1.72

Computer programs: COLLECT (Nonius, 2000), DENZO-SMN (Otwinowski & Minor, 1997), DENZO-SMN, SIR97 (Altomare et al., 1999), Xtal3.6 (Hall et al., 1999), ORTEP-3 (Farrugia, 1997), Xtal3.6 and PLATON (Spek, 2003).

Selected geometric parameters (Å, º) top
Cu1—O111.965 (5)Cu1—O22i1.956 (7)
Cu1—O211.965 (6)Cu2—O112.492 (5)
Cu1—O422.104 (5)Cu2—O311.937 (6)
Cu1—O12i1.987 (6)Cu2—O411.987 (6)
O11—Cu1—O2188.9 (2)O12i—Cu1—O4289.4 (2)
O11—Cu1—O42101.9 (2)O22i—Cu1—O4297.4 (3)
O11—Cu1—O12i168.7 (2)O12i—Cu1—O22i88.9 (3)
O11—Cu1—O22i89.7 (3)O11—Cu2—O3189.8 (2)
O21—Cu1—O4293.6 (2)O11—Cu2—O4195.1 (2)
O12i—Cu1—O2190.3 (2)O31—Cu2—O4187.9 (2)
O21—Cu1—O22i169.0 (3)
Symmetry code: (i) x+2, y, z.
 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds