In the title centrosymmetric dinuclear compound, [Cu
2(C
8H
7O
2)
4(C
8H
8O
2)
2], four
o-toluate anions form a cage around two Cu atoms in a
syn–
syn configuration. Two more
o-toluic acid molecules are apically bonded to the Cu atoms, which show a square-pyramidal coordination geometry. The acid H atoms are hydrogen bonded to the cage carboxyl O atoms [O

O = 2.660 (2) Å]. The molecular packing forms a puckered pseudo-hexagonal close-packed layer in the (
h00) plane, with soft intermolecular H

H contacts (2.46–2.58 Å).
Supporting information
CCDC reference: 684436
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean
(C-C) = 0.002 Å
- R factor = 0.026
- wR factor = 0.066
- Data-to-parameter ratio = 18.1
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000) 200 Deg.
PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 2.64 Ratio
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
2 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
1 ALERT type 2 Indicator that the structure model may be wrong or deficient
0 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
The complex [Cu2(C8H7O2)4(C8H8O2)2] was prepared by heating
o-toluic acid (2.52 g, 18.5 mmol), copper carbonate (0.73 g, 3.3 mmol)
and magnesium oxide (0.19 g, 4.68 mmol) under reflux, in toluene (30 ml) for
24 h. The product was extacted and crystallized from diethyl ether to yield a
blue crystalline solid. (Yield: 84%)
Hydrogen atoms were placed in calculated positions, and they ride on the parent
C-atoms, with U set to 1.2 to 1.5 times Ueq(C).
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).
Tetrakis(µ-2-methylbenzoato)bis[(2-methylbenzoic acid)copper(II)]
top
Crystal data top
[Cu2(C8H7O2)4(C8H8O2)2] | Z = 1 |
Mr = 939.96 | F(000) = 486 |
Triclinic, P1 | Dx = 1.455 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71069 Å |
a = 10.530 (3) Å | Cell parameters from 8974 reflections |
b = 10.579 (3) Å | θ = 2.6–28.3° |
c = 10.773 (4) Å | µ = 1.06 mm−1 |
α = 109.248 (2)° | T = 100 K |
β = 93.156 (2)° | Needle, blue |
γ = 106.287 (2)° | 0.25 × 0.08 × 0.06 mm |
V = 1073.0 (6) Å3 | |
Data collection top
Bruker X8 APEXII 4K KappaCCD diffractometer | 5138 independent reflections |
Radiation source: fine-focus sealed tube | 4668 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
ω and ϕ scans | θmax = 28°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2004b) | h = −13→13 |
Tmin = 0.778, Tmax = 0.939 | k = −13→13 |
17497 measured reflections | l = −14→14 |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.026 | w = 1/[σ2(Fo2) + (0.024P)2 + 0.7431P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.065 | (Δ/σ)max = 0.001 |
S = 1.05 | Δρmax = 0.41 e Å−3 |
5138 reflections | Δρmin = −0.33 e Å−3 |
284 parameters | |
Crystal data top
[Cu2(C8H7O2)4(C8H8O2)2] | γ = 106.287 (2)° |
Mr = 939.96 | V = 1073.0 (6) Å3 |
Triclinic, P1 | Z = 1 |
a = 10.530 (3) Å | Mo Kα radiation |
b = 10.579 (3) Å | µ = 1.06 mm−1 |
c = 10.773 (4) Å | T = 100 K |
α = 109.248 (2)° | 0.25 × 0.08 × 0.06 mm |
β = 93.156 (2)° | |
Data collection top
Bruker X8 APEXII 4K KappaCCD diffractometer | 5138 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2004b) | 4668 reflections with I > 2σ(I) |
Tmin = 0.778, Tmax = 0.939 | Rint = 0.026 |
17497 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.026 | 0 restraints |
wR(F2) = 0.065 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.41 e Å−3 |
5138 reflections | Δρmin = −0.33 e Å−3 |
284 parameters | |
Special details top
Experimental. The intensity data was collected on a Bruker X8 Apex II 4 K Kappa CCD
diffractometer using an exposure time of 30 s/frame. The 1757 frames were
collected with a frame width of 0.5° covering up to θ = 28° with 99.3%
completeness accomplished. |
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 | x | y | z | Uiso*/Ueq | |
Cu1 | 0.444832 (17) | 0.389154 (17) | 0.395103 (17) | 0.01027 (6) | |
O32 | 0.51055 (11) | 0.07974 (12) | 0.26534 (12) | 0.0217 (2) | |
H32 | 0.5525 | 0.1594 | 0.3175 | 0.033* | |
O31 | 0.36065 (11) | 0.18596 (11) | 0.23619 (10) | 0.0154 (2) | |
O21 | 0.47477 (11) | 0.50089 (11) | 0.70973 (10) | 0.0175 (2) | |
O22 | 0.38457 (10) | 0.65099 (11) | 0.57571 (11) | 0.0168 (2) | |
O11 | 0.38005 (11) | 0.30802 (11) | 0.52758 (10) | 0.0157 (2) | |
O12 | 0.29312 (10) | 0.46128 (11) | 0.39073 (10) | 0.0150 (2) | |
C16 | 0.36586 (15) | 0.36861 (16) | 0.87485 (15) | 0.0161 (3) | |
H16 | 0.3999 | 0.4666 | 0.9049 | 0.019* | |
C31 | 0.31192 (15) | −0.05882 (15) | 0.11267 (14) | 0.0142 (3) | |
C11 | 0.35899 (14) | 0.29021 (15) | 0.74017 (14) | 0.0126 (3) | |
C36 | 0.37677 (17) | −0.14773 (16) | 0.03537 (16) | 0.0189 (3) | |
H36 | 0.4698 | −0.1226 | 0.0517 | 0.023* | |
C25 | 0.00903 (16) | 0.72093 (17) | 0.56202 (18) | 0.0235 (3) | |
H25 | −0.0326 | 0.7479 | 0.6358 | 0.028* | |
C321 | 0.09555 (16) | −0.00753 (18) | 0.17572 (17) | 0.0229 (3) | |
H32A | 0.0954 | 0.0674 | 0.1443 | 0.034* | |
H32B | 0.138 | 0.0318 | 0.2672 | 0.034* | |
H32C | 0.0049 | −0.065 | 0.1684 | 0.034* | |
C1 | 0.40786 (14) | 0.37152 (15) | 0.65233 (14) | 0.0127 (3) | |
C12 | 0.30930 (15) | 0.14154 (15) | 0.69355 (15) | 0.0143 (3) | |
C15 | 0.32315 (16) | 0.30349 (17) | 0.96407 (16) | 0.0183 (3) | |
H15 | 0.3285 | 0.3569 | 1.0533 | 0.022* | |
C2 | 0.29274 (14) | 0.57566 (15) | 0.47500 (14) | 0.0119 (3) | |
C13 | 0.26600 (15) | 0.07881 (16) | 0.78583 (16) | 0.0166 (3) | |
H13 | 0.2318 | −0.0191 | 0.7571 | 0.02* | |
C32 | 0.17142 (16) | −0.09665 (16) | 0.09292 (15) | 0.0168 (3) | |
C21 | 0.17807 (14) | 0.62904 (14) | 0.45946 (15) | 0.0131 (3) | |
C33 | 0.10027 (17) | −0.22517 (17) | −0.00704 (16) | 0.0229 (3) | |
H33 | 0.0071 | −0.2536 | −0.0213 | 0.027* | |
C22 | 0.13237 (16) | 0.63473 (16) | 0.33772 (16) | 0.0182 (3) | |
C121 | 0.30291 (18) | 0.04573 (16) | 0.55228 (16) | 0.0211 (3) | |
H12A | 0.278 | −0.0505 | 0.5475 | 0.032* | |
H12B | 0.3892 | 0.0707 | 0.5256 | 0.032* | |
H12C | 0.2375 | 0.0561 | 0.4939 | 0.032* | |
C26 | 0.11778 (16) | 0.67358 (16) | 0.57076 (16) | 0.0175 (3) | |
H26 | 0.151 | 0.6714 | 0.6516 | 0.021* | |
C34 | 0.16490 (19) | −0.31154 (17) | −0.08566 (16) | 0.0254 (4) | |
H34 | 0.1149 | −0.396 | −0.1525 | 0.03* | |
C3 | 0.39545 (15) | 0.08020 (15) | 0.21105 (14) | 0.0137 (3) | |
C35 | 0.30350 (19) | −0.27297 (17) | −0.06539 (16) | 0.0238 (4) | |
H35 | 0.3469 | −0.3305 | −0.1189 | 0.029* | |
C14 | 0.27235 (15) | 0.15762 (17) | 0.91873 (16) | 0.0177 (3) | |
H14 | 0.2425 | 0.1125 | 0.9775 | 0.021* | |
C24 | −0.03711 (16) | 0.72774 (17) | 0.44262 (19) | 0.0261 (4) | |
H24 | −0.11 | 0.7598 | 0.436 | 0.031* | |
C221 | 0.1966 (2) | 0.5912 (2) | 0.21626 (17) | 0.0314 (4) | |
H22A | 0.2917 | 0.6378 | 0.2388 | 0.047* | |
H22B | 0.1603 | 0.6173 | 0.1481 | 0.047* | |
H22C | 0.1789 | 0.4909 | 0.1842 | 0.047* | |
C23 | 0.02467 (17) | 0.68697 (17) | 0.33293 (18) | 0.0250 (4) | |
H23 | −0.0062 | 0.6945 | 0.2539 | 0.03* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.01089 (9) | 0.00896 (9) | 0.01017 (9) | 0.00293 (6) | 0.00121 (6) | 0.00270 (6) |
O32 | 0.0162 (5) | 0.0158 (5) | 0.0258 (6) | 0.0068 (4) | −0.0053 (5) | −0.0019 (5) |
O31 | 0.0165 (5) | 0.0124 (5) | 0.0150 (5) | 0.0054 (4) | −0.0001 (4) | 0.0019 (4) |
O21 | 0.0211 (6) | 0.0135 (5) | 0.0143 (5) | 0.0004 (4) | 0.0038 (4) | 0.0047 (4) |
O22 | 0.0126 (5) | 0.0159 (5) | 0.0178 (5) | 0.0056 (4) | −0.0018 (4) | 0.0006 (4) |
O11 | 0.0205 (5) | 0.0135 (5) | 0.0122 (5) | 0.0031 (4) | 0.0019 (4) | 0.0053 (4) |
O12 | 0.0145 (5) | 0.0132 (5) | 0.0157 (5) | 0.0058 (4) | −0.0003 (4) | 0.0025 (4) |
C16 | 0.0170 (7) | 0.0144 (7) | 0.0160 (7) | 0.0042 (6) | 0.0020 (6) | 0.0052 (6) |
C31 | 0.0177 (7) | 0.0117 (6) | 0.0126 (7) | 0.0041 (6) | 0.0018 (6) | 0.0043 (5) |
C11 | 0.0099 (6) | 0.0153 (7) | 0.0139 (7) | 0.0045 (5) | 0.0023 (5) | 0.0066 (6) |
C36 | 0.0235 (8) | 0.0156 (7) | 0.0187 (8) | 0.0083 (6) | 0.0057 (6) | 0.0057 (6) |
C25 | 0.0163 (8) | 0.0180 (8) | 0.0319 (9) | 0.0058 (6) | 0.0088 (7) | 0.0026 (7) |
C321 | 0.0146 (7) | 0.0262 (8) | 0.0265 (9) | 0.0060 (6) | 0.0035 (6) | 0.0082 (7) |
C1 | 0.0115 (7) | 0.0141 (7) | 0.0142 (7) | 0.0061 (5) | 0.0027 (5) | 0.0055 (5) |
C12 | 0.0121 (7) | 0.0154 (7) | 0.0158 (7) | 0.0048 (6) | 0.0011 (5) | 0.0057 (6) |
C15 | 0.0197 (8) | 0.0227 (8) | 0.0139 (7) | 0.0081 (6) | 0.0042 (6) | 0.0067 (6) |
C2 | 0.0121 (7) | 0.0116 (6) | 0.0131 (7) | 0.0026 (5) | 0.0035 (5) | 0.0066 (5) |
C13 | 0.0134 (7) | 0.0149 (7) | 0.0216 (8) | 0.0028 (6) | 0.0021 (6) | 0.0083 (6) |
C32 | 0.0190 (7) | 0.0156 (7) | 0.0152 (7) | 0.0028 (6) | 0.0008 (6) | 0.0073 (6) |
C21 | 0.0109 (6) | 0.0093 (6) | 0.0169 (7) | 0.0015 (5) | 0.0013 (5) | 0.0038 (5) |
C33 | 0.0232 (8) | 0.0182 (8) | 0.0211 (8) | −0.0025 (6) | −0.0041 (7) | 0.0082 (6) |
C22 | 0.0196 (8) | 0.0158 (7) | 0.0181 (8) | 0.0072 (6) | −0.0005 (6) | 0.0038 (6) |
C121 | 0.0297 (9) | 0.0130 (7) | 0.0189 (8) | 0.0054 (6) | 0.0039 (7) | 0.0048 (6) |
C26 | 0.0165 (7) | 0.0151 (7) | 0.0191 (7) | 0.0040 (6) | 0.0038 (6) | 0.0044 (6) |
C34 | 0.0394 (10) | 0.0137 (7) | 0.0149 (8) | −0.0004 (7) | −0.0029 (7) | 0.0034 (6) |
C3 | 0.0138 (7) | 0.0146 (7) | 0.0120 (7) | 0.0041 (6) | 0.0036 (5) | 0.0043 (5) |
C35 | 0.0401 (10) | 0.0146 (7) | 0.0167 (8) | 0.0110 (7) | 0.0069 (7) | 0.0034 (6) |
C14 | 0.0147 (7) | 0.0242 (8) | 0.0194 (8) | 0.0063 (6) | 0.0046 (6) | 0.0141 (6) |
C24 | 0.0141 (7) | 0.0183 (8) | 0.0399 (10) | 0.0076 (6) | −0.0033 (7) | 0.0022 (7) |
C221 | 0.0442 (11) | 0.0427 (11) | 0.0175 (8) | 0.0258 (9) | 0.0062 (8) | 0.0134 (8) |
C23 | 0.0246 (9) | 0.0205 (8) | 0.0264 (9) | 0.0094 (7) | −0.0085 (7) | 0.0041 (7) |
Geometric parameters (Å, º) top
Cu1—O21i | 1.9402 (12) | C321—H32B | 0.96 |
Cu1—O11 | 1.9559 (12) | C321—H32C | 0.96 |
Cu1—O12 | 1.9585 (13) | C12—C13 | 1.397 (2) |
Cu1—O22i | 1.9900 (13) | C12—C121 | 1.510 (2) |
Cu1—O31 | 2.1622 (13) | C15—C14 | 1.385 (2) |
Cu1—Cu1i | 2.5780 (9) | C15—H15 | 0.93 |
O32—C3 | 1.3184 (19) | C2—C21 | 1.492 (2) |
O32—H32 | 0.82 | C13—C14 | 1.386 (2) |
O31—C3 | 1.2250 (18) | C13—H13 | 0.93 |
O21—C1 | 1.2670 (18) | C32—C33 | 1.394 (2) |
O21—Cu1i | 1.9402 (12) | C21—C26 | 1.394 (2) |
O22—C2 | 1.2764 (18) | C21—C22 | 1.398 (2) |
O22—Cu1i | 1.9900 (13) | C33—C34 | 1.385 (3) |
O11—C1 | 1.2626 (18) | C33—H33 | 0.93 |
O12—C2 | 1.2518 (18) | C22—C23 | 1.399 (2) |
C16—C15 | 1.382 (2) | C22—C221 | 1.502 (2) |
C16—C11 | 1.400 (2) | C121—H12A | 0.96 |
C16—H16 | 0.93 | C121—H12B | 0.96 |
C31—C36 | 1.397 (2) | C121—H12C | 0.96 |
C31—C32 | 1.404 (2) | C26—H26 | 0.93 |
C31—C3 | 1.485 (2) | C34—C35 | 1.384 (3) |
C11—C12 | 1.410 (2) | C34—H34 | 0.93 |
C11—C1 | 1.497 (2) | C35—H35 | 0.93 |
C36—C35 | 1.384 (2) | C14—H14 | 0.93 |
C36—H36 | 0.93 | C24—C23 | 1.383 (3) |
C25—C24 | 1.381 (3) | C24—H24 | 0.93 |
C25—C26 | 1.383 (2) | C221—H22A | 0.96 |
C25—H25 | 0.93 | C221—H22B | 0.96 |
C321—C32 | 1.506 (2) | C221—H22C | 0.96 |
C321—H32A | 0.96 | C23—H23 | 0.93 |
| | | |
O21i—Cu1—O11 | 170.01 (4) | O12—C2—O22 | 124.23 (14) |
O21i—Cu1—O12 | 87.99 (5) | O12—C2—C21 | 118.96 (13) |
O11—Cu1—O12 | 91.79 (5) | O22—C2—C21 | 116.81 (13) |
O21i—Cu1—O22i | 89.93 (5) | C14—C13—C12 | 122.17 (14) |
O11—Cu1—O22i | 88.55 (5) | C14—C13—H13 | 118.9 |
O12—Cu1—O22i | 169.88 (4) | C12—C13—H13 | 118.9 |
O21i—Cu1—O31 | 98.74 (6) | C33—C32—C31 | 117.35 (15) |
O11—Cu1—O31 | 91.16 (6) | C33—C32—C321 | 119.26 (15) |
O12—Cu1—O31 | 99.14 (5) | C31—C32—C321 | 123.37 (14) |
O22i—Cu1—O31 | 90.97 (5) | C26—C21—C22 | 120.83 (14) |
O21i—Cu1—Cu1i | 87.75 (5) | C26—C21—C2 | 117.76 (13) |
O11—Cu1—Cu1i | 82.27 (5) | C22—C21—C2 | 121.41 (13) |
O12—Cu1—Cu1i | 86.61 (4) | C34—C33—C32 | 121.67 (16) |
O22i—Cu1—Cu1i | 83.41 (4) | C34—C33—H33 | 119.2 |
O31—Cu1—Cu1i | 171.44 (3) | C32—C33—H33 | 119.2 |
C3—O32—H32 | 109.5 | C21—C22—C23 | 117.30 (15) |
C3—O31—Cu1 | 129.50 (10) | C21—C22—C221 | 122.57 (15) |
C1—O21—Cu1i | 119.83 (10) | C23—C22—C221 | 120.12 (15) |
C2—O22—Cu1i | 123.41 (10) | C12—C121—H12A | 109.5 |
C1—O11—Cu1 | 125.45 (10) | C12—C121—H12B | 109.5 |
C2—O12—Cu1 | 122.02 (10) | H12A—C121—H12B | 109.5 |
C15—C16—C11 | 121.39 (14) | C12—C121—H12C | 109.5 |
C15—C16—H16 | 119.3 | H12A—C121—H12C | 109.5 |
C11—C16—H16 | 119.3 | H12B—C121—H12C | 109.5 |
C36—C31—C32 | 120.86 (14) | C25—C26—C21 | 120.55 (15) |
C36—C31—C3 | 118.27 (14) | C25—C26—H26 | 119.7 |
C32—C31—C3 | 120.78 (13) | C21—C26—H26 | 119.7 |
C16—C11—C12 | 119.90 (13) | C35—C34—C33 | 120.44 (15) |
C16—C11—C1 | 116.94 (13) | C35—C34—H34 | 119.8 |
C12—C11—C1 | 123.16 (13) | C33—C34—H34 | 119.8 |
C35—C36—C31 | 120.42 (16) | O31—C3—O32 | 123.59 (13) |
C35—C36—H36 | 119.8 | O31—C3—C31 | 122.29 (14) |
C31—C36—H36 | 119.8 | O32—C3—C31 | 114.10 (13) |
C24—C25—C26 | 119.35 (16) | C36—C35—C34 | 119.22 (16) |
C24—C25—H25 | 120.3 | C36—C35—H35 | 120.4 |
C26—C25—H25 | 120.3 | C34—C35—H35 | 120.4 |
C32—C321—H32A | 109.5 | C15—C14—C13 | 120.05 (14) |
C32—C321—H32B | 109.5 | C15—C14—H14 | 120 |
H32A—C321—H32B | 109.5 | C13—C14—H14 | 120 |
C32—C321—H32C | 109.5 | C25—C24—C23 | 120.20 (16) |
H32A—C321—H32C | 109.5 | C25—C24—H24 | 119.9 |
H32B—C321—H32C | 109.5 | C23—C24—H24 | 119.9 |
O11—C1—O21 | 124.51 (13) | C22—C221—H22A | 109.5 |
O11—C1—C11 | 118.61 (13) | C22—C221—H22B | 109.5 |
O21—C1—C11 | 116.88 (13) | H22A—C221—H22B | 109.5 |
C13—C12—C11 | 117.39 (14) | C22—C221—H22C | 109.5 |
C13—C12—C121 | 117.89 (14) | H22A—C221—H22C | 109.5 |
C11—C12—C121 | 124.70 (13) | H22B—C221—H22C | 109.5 |
C16—C15—C14 | 119.09 (15) | C24—C23—C22 | 121.72 (16) |
C16—C15—H15 | 120.5 | C24—C23—H23 | 119.1 |
C14—C15—H15 | 120.5 | C22—C23—H23 | 119.1 |
| | | |
O21i—Cu1—O31—C3 | 108.89 (13) | C11—C12—C13—C14 | −0.8 (2) |
O11—Cu1—O31—C3 | −69.75 (13) | C121—C12—C13—C14 | 177.70 (14) |
O12—Cu1—O31—C3 | −161.75 (13) | C36—C31—C32—C33 | −0.5 (2) |
O22i—Cu1—O31—C3 | 18.81 (13) | C3—C31—C32—C33 | 176.08 (14) |
O12—Cu1—O11—C1 | −88.41 (12) | C36—C31—C32—C321 | 178.06 (14) |
O22i—Cu1—O11—C1 | 81.47 (12) | C3—C31—C32—C321 | −5.4 (2) |
O31—Cu1—O11—C1 | 172.41 (12) | O12—C2—C21—C26 | 131.59 (15) |
Cu1i—Cu1—O11—C1 | −2.08 (11) | O22—C2—C21—C26 | −47.95 (19) |
O21i—Cu1—O12—C2 | −87.01 (12) | O12—C2—C21—C22 | −48.5 (2) |
O11—Cu1—O12—C2 | 83.00 (12) | O22—C2—C21—C22 | 131.91 (15) |
O22i—Cu1—O12—C2 | −8.8 (3) | C31—C32—C33—C34 | −1.1 (2) |
O31—Cu1—O12—C2 | 174.46 (11) | C321—C32—C33—C34 | −179.70 (15) |
Cu1i—Cu1—O12—C2 | 0.85 (11) | C26—C21—C22—C23 | 0.1 (2) |
C15—C16—C11—C12 | −0.8 (2) | C2—C21—C22—C23 | −179.71 (14) |
C15—C16—C11—C1 | 179.95 (14) | C26—C21—C22—C221 | 178.43 (16) |
C32—C31—C36—C35 | 2.2 (2) | C2—C21—C22—C221 | −1.4 (2) |
C3—C31—C36—C35 | −174.48 (14) | C24—C25—C26—C21 | −1.9 (2) |
Cu1—O11—C1—O21 | 5.1 (2) | C22—C21—C26—C25 | 1.7 (2) |
Cu1—O11—C1—C11 | −175.02 (9) | C2—C21—C26—C25 | −178.42 (14) |
Cu1i—O21—C1—O11 | −5.4 (2) | C32—C33—C34—C35 | 1.0 (2) |
Cu1i—O21—C1—C11 | 174.78 (9) | Cu1—O31—C3—O32 | −13.1 (2) |
C16—C11—C1—O11 | −166.58 (13) | Cu1—O31—C3—C31 | 168.70 (10) |
C12—C11—C1—O11 | 14.2 (2) | C36—C31—C3—O31 | 144.89 (15) |
C16—C11—C1—O21 | 13.27 (19) | C32—C31—C3—O31 | −31.8 (2) |
C12—C11—C1—O21 | −165.91 (14) | C36—C31—C3—O32 | −33.43 (19) |
C16—C11—C12—C13 | 1.3 (2) | C32—C31—C3—O32 | 149.91 (14) |
C1—C11—C12—C13 | −179.57 (13) | C31—C36—C35—C34 | −2.2 (2) |
C16—C11—C12—C121 | −177.11 (14) | C33—C34—C35—C36 | 0.7 (2) |
C1—C11—C12—C121 | 2.1 (2) | C16—C15—C14—C13 | 0.6 (2) |
C11—C16—C15—C14 | −0.1 (2) | C12—C13—C14—C15 | −0.2 (2) |
Cu1—O12—C2—O22 | −5.0 (2) | C26—C25—C24—C23 | 0.3 (2) |
Cu1—O12—C2—C21 | 175.52 (9) | C25—C24—C23—C22 | 1.6 (3) |
Cu1i—O22—C2—O12 | 7.4 (2) | C21—C22—C23—C24 | −1.8 (2) |
Cu1i—O22—C2—C21 | −173.12 (9) | C221—C22—C23—C24 | 179.87 (17) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O32—H32···O22i | 0.82 | 1.85 | 2.6604 (18) | 168 |
C16—H16···O21 | 0.93 | 2.39 | 2.721 (2) | 101 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | [Cu2(C8H7O2)4(C8H8O2)2] |
Mr | 939.96 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 100 |
a, b, c (Å) | 10.530 (3), 10.579 (3), 10.773 (4) |
α, β, γ (°) | 109.248 (2), 93.156 (2), 106.287 (2) |
V (Å3) | 1073.0 (6) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 1.06 |
Crystal size (mm) | 0.25 × 0.08 × 0.06 |
|
Data collection |
Diffractometer | Bruker X8 APEXII 4K KappaCCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2004b) |
Tmin, Tmax | 0.778, 0.939 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 17497, 5138, 4668 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.661 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.065, 1.05 |
No. of reflections | 5138 |
No. of parameters | 284 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.41, −0.33 |
Selected bond lengths (Å) topCu1—O21i | 1.9402 (12) | Cu1—Cu1i | 2.5780 (9) |
Cu1—O11 | 1.9559 (12) | C31—C3 | 1.485 (2) |
Cu1—O12 | 1.9585 (13) | C11—C1 | 1.497 (2) |
Cu1—O22i | 1.9900 (13) | C2—C21 | 1.492 (2) |
Cu1—O31 | 2.1622 (13) | | |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O32—H32···O22i | 0.82 | 1.85 | 2.6604 (18) | 167.6 |
C16—H16···O21 | 0.93 | 2.39 | 2.721 (2) | 100.9 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
In our endeavours to produce phenols from aromatic carboxylic acids, we came across work by Kaeding (1967). In order to verify the reaction sequence as proposed by Kaeding, we prepared the copper salt of o-toluic acid and obtained single crystals.
The title compound, (I), [Cu2(C8H7O2)4(C8H8O2)2] crystallized with molecular symmetry -1 (Fig.1). The title compound exhibits a cage-like structure. Four o-toluic anionic ligands form a cage around two Cu-atoms in a syn-syn configuration. Two more carboxylic acid are apically bonded to the Cu-atoms. The acid protons are hydrogen bonded to the cage carboxylate O atoms, O32—H32···O22 = 167.6° and O32···O22 = 2.6604 (18) Å. Another intra-molecular H···H short contact is present at C16···O21 with C16—H16···O21 = 100.9° and C16···O21 = 2.721 (2) Å.
Comparing the Van der Waals radii of copper, 2.32 Å, and the metallic Cu—Cu bond length, 2.55 Å, to the Cu—Cu separation in (I), 2.5780 (9) Å, one would expect the presence of weak orbital interaction. The Cu—O bond lengths of the cage carboxylates vary between 1.9402 (12) - 1.9900 (13) Å. The Cu—O bond distances to the adducted acid molecules show a ca 0.2 Å increase. Each Cu atom is displaced from the basal plane of the four caged carboxylates by 0.171 Å, towards the apical O atom. Compound (I) forms a puckered pseudo-hexagonal close packed layer in the (h 0 0) plane, with soft inter-molecular H···H contacts, 2.457–2.580 Å (Fig.2).