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The title complex [systematic name: trans-bis(3-iso­propyl-7-oxo­cyclo­hepta-1,3,5-trienolato)copper(II)], [Cu(C10H11O2)2], is a substance possessing antimicrobial activity. The compound crystallizes in a number of polymorphic forms, the structures for two of which are reported here. Stacks of square-planar mol­ecules exhibiting weak intermolecular copper–olefin π interactions (not observed in earlier reports on this substance) are described. The mol­ecules have crystallographically imposed inversion symmetry, with stacking and copper–olefin π distances ranging from 3.226 (2) to 3.336 (1) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104001957/fr1457sup1.cif
Contains datablocks global, Ia, Ib

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104001957/fr1457Iasup2.hkl
Contains datablock Ia

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104001957/fr1457Ibsup3.hkl
Contains datablock Ib

CCDC references: 235319; 235320

Comment top

Metal complexes of tropolone derivatives have engaged the interest of researchers in such diverse areas as material science and medicinal chemistry. Some of that interest has been focused on hinokitiol (β-thujaplicin), a tropolone and natural product first isolated from Chamaecyparis taiwanensis (Nozoe, 1936). Hinokitiol and its metal complexes have since been shown to exhibit a wide variety of biological activities, e.g. antibacterial, antifungal and antiviral activities among others (Miyamoto et al., 1998; Arima et al., 2003; Morita et al., 2003). Hinokitiol complexes of Cu, Zn and Sn have also been reported to be effective in oral care formulations (Creeth et al., 2000), and the structures of a Cu hinokitiol monomer and of a modification containing both monomers and dimers have been published as a part of those studies (Barret et al., 2002). We have observed, however, that the reported monomer, i.e. trans-bis(hinokitiolato)copper(II), actually exists in a number of additional polymorphic forms. A triclinic form, (Ia), and a new monoclinic form, (Ib), have been obtained from ethanol–water solutions and are reported here. The previously published monoclinic form, (Ic), was obtained from ethanol. Views of (Ia) and (Ib) are given in Fig. 1, and selected distances and angles are summarized in Table 1.

Form (Ia) crystallizes in the triclinic space group P1, while forms (Ib) and (Ic) crystallize in the monoclinic space group P21/c. In all three forms, the Cu atoms reside on centers of crystallographic inversion symmetry and have square-planar coordination geometries. The Cu—O bonds in (Ia) are statistically non-equivalent, while those in (Ib) are equivalent. The Cu—O bonds in (Ic) are also equal in length, albeit significantly shorter than those observed in (Ib). Comparable equivalent and non-equivalent Cu—O bonds have been observed in related Cu–tropolonato complexes (Hasegawa et al., 1997; Chipperfield et al., 1998) and in Cu complexes involving α- or β-hydroxy ketone ligands (Lim et al., 1994; Odoko et al., 2002). The O—Cu—O bite angles for the chelating hinokitiolato ligands in all three polymorphs are also statistically equivalent.

Trans-bis(hinokitiolato)copper(II) is essentially a planar molecule. The r.m.s. deviation of atoms from a least-squares plane through the molecule (excluding the isopropyl atoms) is 0.017 (2) Å for (Ia) and 0.071 (2) Å for (Ib). The less planar nature of (Ib) is visible in Fig. 2 as a slight folding of the molecule along the O1···O2 and O1i···O2i vectors [the interplanar angle between the CuO4 coordination plane and each tropolone ligand plane is 172.9 (1)°]. In contrast, (Ia) and (Ic) are essentially planar, with corresponding interplanar angles of 178.3 (1) and 178.9 (2)°, respectively. These conformational differences in the trans-bis(hinokitiolato)copper(II) molecules are attributed to packing forces.

The packings of trans-bis(hinokitiolato)copper(II) molecules in (Ia) and (Ib) share a number of similarities (Fig. 2) but differ completely from that observed in the previously published (Ic). Most notably, the molecules in (Ia) and (Ib) pack into extended columns or stacks, while those in (Ic) do not. Consequently, the Cu atoms in (Ia) and (Ib) are pseudo-six-coordinate, with weak apical interactions, while the Cu atoms in (Ic) are formally four-coordinate. Interestingly, the apical interactions in (Ia) and (Ib) also differ. The apical interactions in (Ia) are best described as involving π-electron densities distributed over the C1—C7—C6—C5—C4 portion of neighboring hinokitiolato ligands, while the apical interactions in (Ib) involve only the C4—C5 edge of neighboring molecules. The Cu atom is 3.336 (1) Å from the centroid defined by atoms C1, C4, C5, C6 and C7 atoms in (Ia), and 3.226 (2) Å from the centroid of the C4—C5 bond in (Ib). These distances are comparable to values [3.25–3.55 Å] observed for longer-range non-covalent CuII···arene contacts (Mascal et al., 2000).

Thus, the packing and stacking of molecules in (Ia) and (Ib) are consistent with the presence of weak apical η5 and η2 Cu–olefin π interactions, respectively. The distance between the least-squares planes through adjacent molecules, or stacking distance, is 3.336 (1) Å for (Ia) and 3.235 (2) Å for (Ib), and the Cu···Cu distances between neighboring molecules within the stacks are 5.1549 (3) Å for (Ia) and 6.7470 (1) Å for (Ib), i.e. a unit translation in the crystallographic a and b directions, respectively. Furthermore, as shown in Fig. 2, the molecules do not stack directly on top of one another, but instead slide over each other by 3.930 (1) and 5.921 (2) Å in (Ia) and (Ib), respectively.

The triclinic form also differs from (Ib) in that there are weak interstack C—H···O hydrogen-bonding interactions present in (Ia). The C6—H6, H6···O2ii and C6.·O2ii distances are 0.93, 2.51 and 3.348 (4) Å, respectively, and the C6—H6···O2ii angle is 150.4° [symmetry code: (ii) 1 − x, −y, 2 − z]. Whether these hydrogen-bonding interactions contribute to the non-equivalence of the Cu—O bonds in (Ia) is not known at this time.

Experimental top

The title compound was isolated from the reaction of copper gluconate and hinokitiol (Aldrich Chemical Company) in a 1:2 molar ratio. An aqueous solution of copper gluconate was added to a solution of hinokitiol in ethanol and the mixture stirred for 1 h. The resulting green precipitate was collected and recrystallized from aqueous ethanol. An assortment of crystal morphologies was immediately evident in the recrystallized product. Both (Ia) and (Ib) crystallize as green–yellow needles, but the two forms have noticeably different physical properties that aid in their identification. Crystals of (Ia) are soft and often distort or split into layers when attempts are made to cut them. Crystals of (Ib) are dichroic, i.e. green–yellow when viewed perpendicular to the 001 face and olive green when viewed perpendicular to the 100 face. The previously published polymorph, (Ic), crystallizes as olive-green multifaceted prisms.

Refinement top

All H atoms were allowed to ride on their respective C atoms, with C—H distances constrained to the SHELXTL default values for the specified functional groups and temperatures. The SHELXTL internal defaults for the tropolone, isopropyl methine and methyl H atoms were 0.93, 0.98 and 0.96 Å for (Ia) at 298 K, and 0.95, 1.00 and 0.98 Å for (Ib) at 200 K, respectively. The Uiso(H) values were se to 1.2Ueq(C) for the tropolone and isopropyl methine H atoms, and 1.5Ueq(C) for the methyl H atoms.

Computing details top

For both compounds, data collection: COLLECT (Nonius, 1998); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN and SHELXTL (Sheldrick, 1996). Program(s) used to solve structure: SHELXS86 (Sheldrick, 1990) for (Ia); SHELXTL for (Ib). For both compounds, program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. Polymorphs (Ia) (top) at 298 K and (Ib) (bottom) at 200 K. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) −x, 1 − y, 2 − z; (ii) 1 − x, −y, −z.]
[Figure 2] Fig. 2. Stacking and π interactions in Ia (top) and Ib (bottom).
(Ia) trans-Bis(3-isopropyl-7-oxocyclohepta-1,3,5-trienolato)copper(II), Triclinic Form Ia top
Crystal data top
[Cu(C10H11O2)2]Z = 1
Mr = 389.92F(000) = 203
Triclinic, P1Dx = 1.404 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 5.1549 (3) ÅCell parameters from 6146 reflections
b = 6.9872 (4) Åθ = 1.5–27.5°
c = 13.9097 (8) ŵ = 1.20 mm1
α = 77.747 (3)°T = 298 K
β = 84.255 (3)°Needle, green–yellow
γ = 70.508 (3)°0.29 × 0.08 × 0.04 mm
V = 461.30 (5) Å3
Data collection top
Nonius KappaCCD
diffractometer
2096 independent reflections
Radiation source: fine-focus sealed tube1541 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.064
ω scans; 400 1.0° rotationsθmax = 27.5°, θmin = 1.5°
Absorption correction: gaussian
SHELXTL (Sheldrick, 1996)
h = 66
Tmin = 0.786, Tmax = 0.955k = 89
6146 measured reflectionsl = 1718
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.048H-atom parameters constrained
wR(F2) = 0.107 w = 1/[σ2(Fo2) + (0.0469P)2 + 0.197P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.001
2095 reflectionsΔρmax = 0.27 e Å3
118 parametersΔρmin = 0.51 e Å3
0 restraintsExtinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: heavy-atom methodExtinction coefficient: 0.032 (7)
Crystal data top
[Cu(C10H11O2)2]γ = 70.508 (3)°
Mr = 389.92V = 461.30 (5) Å3
Triclinic, P1Z = 1
a = 5.1549 (3) ÅMo Kα radiation
b = 6.9872 (4) ŵ = 1.20 mm1
c = 13.9097 (8) ÅT = 298 K
α = 77.747 (3)°0.29 × 0.08 × 0.04 mm
β = 84.255 (3)°
Data collection top
Nonius KappaCCD
diffractometer
2096 independent reflections
Absorption correction: gaussian
SHELXTL (Sheldrick, 1996)
1541 reflections with I > 2σ(I)
Tmin = 0.786, Tmax = 0.955Rint = 0.064
6146 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.107H-atom parameters constrained
S = 1.07Δρmax = 0.27 e Å3
2095 reflectionsΔρmin = 0.51 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.

The observed Cu(1)···C(n) distances are 3.768 (3), 3.911 (3), 3.956 (3), 3.800 (3), 3.612 (3), 3.530 (3) and 3.586 (3) Angstroms for n = 1–7, respectively.

The stacking distance (i.e., the distance between the least-squares planes through neighboring molecules) is 3.336 (1) Angstroms. The Cu(1) atom is also 3.336 (1) Angstroms off of the centroid defined by the atoms [C(1),C(4),C(5),C(6),C(7)]. This metal···centroid distance falls within the range of distances (i.e., 3.25–3.55 Angstroms) seen for longer-range non-covalent Cu(II)···arene contacts [see Mascal, M.; Kerdelhue, J.-L.; Blake, A. J.; Cooke, P. A.; Mortimer, R. J.; Teat, S. J. European Journal of Inorganic Chemistry 2000, 485–490].

The Cu···Cu distance between neighboring molecules within a stack is 5.1549 (3) Angstroms, i.e., the length of the a axis. The angle between the Cu···Cu vector and the least-squares plane through any molecule in a stack is 40.33 (3) degrees.

The molecules do not stack directly on top of one another. A slippage of 3.930 (1) Angstroms is observed.

Weak inter-stack C—H···O interactions may also be present. The following distances (in Angstroms) and angles (in degrees) are noted:

C(6)—H(6) 0.93 H(6)···O2 (1 − x, −y, 2 − z) 2.51 C(6)···O2 (1 − x, −y, 2 − z) 3.348 (4) C(6)—H(6)···O2 (1 − x, −y, 2 − z) 150.4

The van der Waals radii for C, H and O are 1.70, 1.20 and 1.52 Angstroms, respectively. The H···O distance of 2.51 Angstroms is less than the sum of the H and O radii (i.e., 1.20 + 1.52 = 2.72 Angstroms). The C···O distance of 3.348 (4) is just slightly larger than the sum of the C and O radii (i.e., 1.70 + 1.52 = 3.22 Angstroms). The involvement of the O(2) atoms in these weak inter-stack interactions may be part of the reason why non-equivalent Cu—O bonds are observed.

Each trans-bis(3-isopropyl-7-oxocyclohepta-1,3,5-trienolato)copper(II) molecule is essentially planar. The r.m.s. deviation of atoms from a least-squares plane through the molecule (excluding the isopropyl atoms is 0.017 (2) Angstroms. The maximum deviation from that plane is 0.034 (2) Angstroms for the O(2) atom.

The interplanar angle between the CuO4 coordination plane and each C7O2 ligand plane is 178.3 (1) degrees, i.e., the molecule is folded very, very slightly along the O(1)···O(2) and O(1) (-x, 1 − y, 2 − z)···O(2) (-x, 1 − y, 2 − z) vectors.

Refinement. Refinement on F2 for ALL reflections except for 1 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs 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*/Ueq
Cu10.00000.50001.00000.0568 (3)
O10.1550 (4)0.6439 (3)0.8888 (2)0.0584 (5)
O20.3359 (4)0.2814 (3)0.9917 (2)0.0613 (6)
C10.3933 (6)0.5318 (4)0.8600 (2)0.0486 (7)
C20.5254 (6)0.6159 (5)0.7781 (2)0.0553 (7)
H20.42500.75010.74940.066*
C30.7790 (6)0.5386 (5)0.7304 (2)0.0529 (7)
C40.9689 (6)0.3433 (5)0.7571 (2)0.0596 (8)
H41.13070.31620.71870.072*
C50.9517 (7)0.1836 (5)0.8325 (2)0.0617 (8)
H51.10360.06420.83670.074*
C60.7460 (6)0.1729 (5)0.9023 (2)0.0602 (8)
H60.77770.04610.94510.072*
C70.4956 (6)0.3238 (4)0.9189 (2)0.0501 (7)
C80.8502 (7)0.6808 (6)0.6402 (3)0.0675 (9)
H81.04600.61930.62400.081*
C90.8097 (9)0.8972 (6)0.6569 (3)0.0845 (11)
H9A0.90020.88790.71550.127*
H9B0.61650.96920.66400.127*
H9C0.88670.97090.60160.127*
C100.6896 (10)0.6872 (8)0.5524 (3)0.0949 (13)
H10A0.72600.54910.54190.142*
H10B0.74560.76870.49470.142*
H10C0.49610.74770.56560.142*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0534 (3)0.0577 (4)0.0546 (4)0.0146 (2)0.0048 (2)0.0090 (3)
O10.0519 (11)0.0543 (13)0.0580 (13)0.0079 (10)0.0088 (9)0.0070 (10)
O20.0574 (12)0.0581 (13)0.0591 (13)0.0143 (10)0.0058 (10)0.0021 (10)
C10.0482 (15)0.048 (2)0.048 (2)0.0125 (13)0.0008 (12)0.0110 (13)
C20.051 (2)0.051 (2)0.056 (2)0.0100 (13)0.0021 (14)0.0060 (14)
C30.053 (2)0.056 (2)0.052 (2)0.0199 (14)0.0007 (13)0.0126 (14)
C40.054 (2)0.062 (2)0.063 (2)0.0153 (15)0.0072 (14)0.021 (2)
C50.057 (2)0.052 (2)0.068 (2)0.0086 (14)0.005 (2)0.014 (2)
C60.060 (2)0.050 (2)0.063 (2)0.0109 (14)0.0004 (15)0.0047 (15)
C70.051 (2)0.048 (2)0.049 (2)0.0147 (13)0.0018 (13)0.0082 (13)
C80.058 (2)0.076 (2)0.062 (2)0.020 (2)0.010 (2)0.008 (2)
C90.096 (3)0.076 (3)0.080 (3)0.038 (2)0.006 (2)0.000 (2)
C100.110 (3)0.120 (4)0.055 (2)0.043 (3)0.006 (2)0.010 (2)
Geometric parameters (Å, º) top
Cu1—O2i1.901 (2)C5—C61.374 (4)
Cu1—O21.901 (2)C5—H50.93
Cu1—O11.915 (2)C6—C71.402 (4)
Cu1—O1i1.915 (2)C6—H60.93
O1—C11.295 (3)C8—C91.520 (5)
O2—C71.289 (4)C8—C101.527 (5)
C1—C21.391 (4)C8—H80.98
C1—C71.460 (4)C9—H9A0.96
C2—C31.395 (4)C9—H9B0.96
C2—H20.93C9—H9C0.96
C3—C41.387 (4)C10—H10A0.96
C3—C81.523 (4)C10—H10B0.96
C4—C51.380 (5)C10—H10C0.96
C4—H40.93
O2i—Cu1—O2180.0C5—C6—H6115.0
O2i—Cu1—O196.30 (9)C7—C6—H6115.0
O2—Cu1—O183.70 (9)O2—C7—C6119.3 (3)
O2i—Cu1—O1i83.70 (9)O2—C7—C1115.0 (3)
O2—Cu1—O1i96.30 (9)C6—C7—C1125.7 (3)
O1—Cu1—O1i180.0C9—C8—C3113.7 (3)
C1—O1—Cu1113.0 (2)C9—C8—C10111.4 (3)
C7—O2—Cu1113.5 (2)C3—C8—C10109.9 (3)
O1—C1—C2118.9 (3)C9—C8—H8107.1
O1—C1—C7114.7 (3)C3—C8—H8107.1
C2—C1—C7126.4 (3)C10—C8—H8107.1
C1—C2—C3132.7 (3)C8—C9—H9A109.5
C1—C2—H2113.7C8—C9—H9B109.5
C3—C2—H2113.7H9A—C9—H9B109.5
C4—C3—C2125.8 (3)C8—C9—H9C109.5
C4—C3—C8117.4 (3)H9A—C9—H9C109.5
C2—C3—C8116.8 (3)H9B—C9—H9C109.5
C5—C4—C3129.2 (3)C8—C10—H10A109.5
C5—C4—H4115.4C8—C10—H10B109.5
C3—C4—H4115.4H10A—C10—H10B109.5
C6—C5—C4130.3 (3)C8—C10—H10C109.5
C6—C5—H5114.8H10A—C10—H10C109.5
C4—C5—H5114.8H10B—C10—H10C109.5
C5—C6—C7129.9 (3)
O2i—Cu1—O1—C1177.9 (2)C4—C5—C6—C71.9 (6)
O2—Cu1—O1—C12.1 (2)Cu1—O2—C7—C6177.7 (2)
O1—Cu1—O2—C72.4 (2)Cu1—O2—C7—C12.3 (3)
O1i—Cu1—O2—C7177.6 (2)C5—C6—C7—O2177.6 (3)
Cu1—O1—C1—C2178.2 (2)C5—C6—C7—C12.4 (5)
Cu1—O1—C1—C71.4 (3)O1—C1—C7—O20.5 (4)
O1—C1—C2—C3178.9 (3)C2—C1—C7—O2179.8 (3)
C7—C1—C2—C31.5 (5)O1—C1—C7—C6179.5 (3)
C1—C2—C3—C40.4 (5)C2—C1—C7—C60.2 (5)
C1—C2—C3—C8179.3 (3)C4—C3—C8—C9131.5 (3)
C2—C3—C4—C51.5 (5)C2—C3—C8—C949.5 (4)
C8—C3—C4—C5177.5 (3)C4—C3—C8—C10102.8 (3)
C3—C4—C5—C60.7 (6)C2—C3—C8—C1076.2 (4)
Symmetry code: (i) x, y+1, z+2.
(Ib) Trans-Bis(3-Isopropyl-7-oxocyclohepta-1,3,5-trienolato)copper(II), Monoclinic Form Ib top
Crystal data top
[Cu(C10H11O2)2]F(000) = 406
Mr = 389.92Dx = 1.457 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 23670 reflections
a = 8.7410 (2) Åθ = 2.4–27.5°
b = 6.7470 (1) ŵ = 1.25 mm1
c = 15.3448 (4) ÅT = 200 K
β = 100.800 (1)°Needle, green–yellow
V = 888.94 (3) Å30.22 × 0.12 × 0.05 mm
Z = 2
Data collection top
Nonius KappaCCD
diffractometer
2040 independent reflections
Radiation source: fine-focus sealed tube1591 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.076
ω scans; 800 1.0° rotationsθmax = 27.5°, θmin = 2.4°
Absorption correction: gaussian
SHELXTL (Sheldrick, 1996)
h = 1111
Tmin = 0.794, Tmax = 0.948k = 87
23670 measured reflectionsl = 1919
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)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.112H-atom parameters constrained
S = 1.12 w = 1/[σ2(Fo2) + (0.0549P)2 + 1.192P]
where P = (Fo2 + 2Fc2)/3
2040 reflections(Δ/σ)max < 0.001
117 parametersΔρmax = 0.70 e Å3
0 restraintsΔρmin = 0.83 e Å3
Crystal data top
[Cu(C10H11O2)2]V = 888.94 (3) Å3
Mr = 389.92Z = 2
Monoclinic, P21/cMo Kα radiation
a = 8.7410 (2) ŵ = 1.25 mm1
b = 6.7470 (1) ÅT = 200 K
c = 15.3448 (4) Å0.22 × 0.12 × 0.05 mm
β = 100.800 (1)°
Data collection top
Nonius KappaCCD
diffractometer
2040 independent reflections
Absorption correction: gaussian
SHELXTL (Sheldrick, 1996)
1591 reflections with I > 2σ(I)
Tmin = 0.794, Tmax = 0.948Rint = 0.076
23670 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.112H-atom parameters constrained
S = 1.12Δρmax = 0.70 e Å3
2040 reflectionsΔρmin = 0.83 e Å3
117 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.

In both the Triclinic Form Ia and the Monoclinic Form Ib, the copper atoms are involved in weak apical interactions with pi-electrons from neighboring molecules above and below the CuO4 equatorial planes. The interaction in the Triclinic Form Ia involves an extented pi-system of electron density, while the interaction in the Monoclinic Form Ib is best described as involving pi-electron density predominantly in the vicinity of one C—C bond unit in particular, i.e., C(4)—C(5). The observed Cu(1)···C(4) and Cu(1)···C(5) distances are 3.277 (3) and 3.321 (3) Angstroms, respectively.

The stacking distance (i.e., the distance between the least-squares planes through neighboring molecules) is 3.235 (2) Angstroms, and the distance of the Cu(1) atom to the centroid of the C(4)—C(5) bond is 3.226 (2) Angstroms. These distances are consistent with the presence of a weak contact between the Cu(1) atom and the cycloheptatriene ring. Distances ranging from 3.25 to 3.55 Angstroms have been observed for longer-range non-covalent Cu(II)···arene contacts [see Mascal, M.; Kerdelhue, J.-L.; Blake, A. J.; Cooke, P. A.; Mortimer, R. J.; Teat, S. J. European Journal of Inorganic Chemistry 2000, 485–490].

The Cu···Cu distance between neighboring molecules within a stack is 6.7470 (1) Angstroms, i.e., the length of the b axis. The angle between the Cu···Cu vector and the least-squares plane through any molecule in a stack is 28.65 (3) degrees.

The molecules do not stack directly on top of one another. A slippage of 5.921 (2) Angstroms is observed.

Each trans-bis-(3-isopropyl-7-oxocyclohepta-1,3,5-trienolato)copper(II) molecule in Monoclinic Form Ib is essentially planar; although less so than in the Triclinic Form Ia and in the Monoclinic Form Ic. The r.m.s. deviation of atoms from the least-squares plane through the molecule (excluding the isopropyl atoms) is 0.071 (2) Angstroms. The maximum deviation from that plane is 0.114 (2) Angstroms for the O(2) atom.

The interplanar angle between the CuO4 coordination plane and each C7O2 ligand plane is 172.9 (1) degrees, i.e., each molecule exhibits a slight fold along the O(1)···O(2) and O(1) (1 − x, −y, −z)···O(2) (1 − x, −y, −z) vectors. Hence, the molecules in this new Monoclinic Form Ib are slightly more bent compared to those in the Triclinic Form Ia [178.3 (1) degrees] and in the published Monoclinic Form Ic [178.9 (2) degrees] of trans-bis-(3-isopropyl-7-oxocyclohepta-1,3,5-trienolato)copper(II).

Refinement. Refinement on F2 for ALL reflections except for 0 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs 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*/Ueq
Cu10.50000.00000.00000.0310 (2)
O10.3455 (2)0.1528 (3)0.04383 (14)0.0344 (5)
O20.6402 (2)0.1973 (3)0.05823 (14)0.0353 (5)
C10.4003 (3)0.3156 (4)0.0817 (2)0.0287 (6)
C20.2971 (3)0.4494 (5)0.1098 (2)0.0313 (6)
H20.19250.40360.10050.038*
C30.3176 (3)0.6367 (4)0.1489 (2)0.0293 (6)
C40.4592 (3)0.7363 (4)0.1735 (2)0.0320 (6)
H40.45370.86170.20100.038*
C50.6064 (3)0.6766 (4)0.1633 (2)0.0332 (6)
H50.68740.76750.18540.040*
C60.6548 (3)0.5058 (4)0.1261 (2)0.0289 (6)
H60.76320.49960.12550.035*
C70.5691 (3)0.3414 (4)0.0894 (2)0.0290 (6)
C80.1710 (3)0.7408 (4)0.1658 (2)0.0339 (6)
H80.20330.87240.19320.041*
C90.0943 (4)0.6255 (5)0.2314 (2)0.0407 (7)
H9A0.00070.69600.24080.061*
H9B0.16740.61330.28790.061*
H9C0.06540.49320.20760.061*
C100.0566 (4)0.7796 (5)0.0790 (2)0.0459 (8)
H10A0.02910.86280.09100.069*
H10B0.01490.65330.05340.069*
H10C0.11070.84760.03720.069*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0314 (3)0.0285 (3)0.0332 (3)0.0006 (2)0.0061 (2)0.0039 (2)
O10.0314 (10)0.0287 (11)0.0431 (11)0.0024 (8)0.0069 (8)0.0068 (9)
O20.0310 (10)0.0372 (12)0.0381 (11)0.0012 (9)0.0072 (8)0.0075 (9)
C10.0296 (14)0.0278 (15)0.0289 (13)0.0019 (11)0.0057 (11)0.0003 (11)
C20.0258 (13)0.033 (2)0.0351 (14)0.0017 (11)0.0052 (11)0.0018 (12)
C30.0322 (14)0.0248 (14)0.0300 (13)0.0014 (11)0.0035 (11)0.0021 (11)
C40.0371 (15)0.0260 (15)0.0321 (14)0.0030 (12)0.0045 (12)0.0018 (11)
C50.0315 (14)0.034 (2)0.0331 (15)0.0067 (12)0.0023 (11)0.0027 (12)
C60.0233 (12)0.032 (2)0.0308 (14)0.0008 (11)0.0048 (10)0.0002 (11)
C70.0300 (13)0.032 (2)0.0250 (13)0.0012 (11)0.0047 (10)0.0023 (11)
C80.0339 (15)0.0244 (15)0.043 (2)0.0024 (11)0.0054 (12)0.0033 (12)
C90.040 (2)0.036 (2)0.048 (2)0.0049 (13)0.0133 (14)0.0017 (14)
C100.039 (2)0.047 (2)0.050 (2)0.0132 (15)0.0051 (15)0.009 (2)
Geometric parameters (Å, º) top
Cu1—O2i1.913 (2)C5—C61.387 (4)
Cu1—O21.913 (2)C5—H50.95
Cu1—O11.918 (2)C6—C71.397 (4)
Cu1—O1i1.918 (2)C6—H60.95
O1—C11.292 (3)C8—C91.523 (4)
O2—C71.293 (3)C8—C101.531 (4)
C1—C21.400 (4)C8—H81.00
C1—C71.468 (4)C9—H9A0.98
C2—C31.396 (4)C9—H9B0.98
C2—H20.95C9—H9C0.98
C3—C41.397 (4)C10—H10A0.98
C3—C81.526 (4)C10—H10B0.98
C4—C51.385 (4)C10—H10C0.98
C4—H40.95
O2i—Cu1—O2180.0C5—C6—H6115.0
O2i—Cu1—O196.10 (8)C7—C6—H6115.0
O2—Cu1—O183.90 (8)O2—C7—C6119.2 (2)
O2i—Cu1—O1i83.90 (8)O2—C7—C1115.2 (2)
O2—Cu1—O1i96.10 (8)C6—C7—C1125.6 (3)
O1—Cu1—O1i180.0C9—C8—C3111.4 (2)
C1—O1—Cu1112.9 (2)C9—C8—C10111.4 (3)
C7—O2—Cu1112.7 (2)C3—C8—C10111.3 (2)
O1—C1—C2118.7 (2)C9—C8—H8107.5
O1—C1—C7114.8 (2)C3—C8—H8107.5
C2—C1—C7126.5 (3)C10—C8—H8107.5
C3—C2—C1132.7 (3)C8—C9—H9A109.5
C3—C2—H2113.7C8—C9—H9B109.5
C1—C2—H2113.7H9A—C9—H9B109.5
C2—C3—C4126.0 (3)C8—C9—H9C109.5
C2—C3—C8116.5 (2)H9A—C9—H9C109.5
C4—C3—C8117.5 (3)H9B—C9—H9C109.5
C5—C4—C3128.6 (3)C8—C10—H10A109.5
C5—C4—H4115.7C8—C10—H10B109.5
C3—C4—H4115.7H10A—C10—H10B109.5
C4—C5—C6130.5 (3)C8—C10—H10C109.5
C4—C5—H5114.7H10A—C10—H10C109.5
C6—C5—H5114.7H10B—C10—H10C109.5
C5—C6—C7130.1 (3)
O2i—Cu1—O1—C1174.0 (2)C4—C5—C6—C71.4 (5)
O2—Cu1—O1—C16.0 (2)Cu1—O2—C7—C6173.9 (2)
O1—Cu1—O2—C76.4 (2)Cu1—O2—C7—C15.7 (3)
O1i—Cu1—O2—C7173.6 (2)C5—C6—C7—O2180.0 (3)
Cu1—O1—C1—C2174.6 (2)C5—C6—C7—C10.5 (5)
Cu1—O1—C1—C74.6 (3)O1—C1—C7—O20.7 (4)
O1—C1—C2—C3177.2 (3)C2—C1—C7—O2179.8 (3)
C7—C1—C2—C31.8 (5)O1—C1—C7—C6178.8 (3)
C1—C2—C3—C42.9 (5)C2—C1—C7—C60.3 (5)
C1—C2—C3—C8177.1 (3)C2—C3—C8—C963.0 (3)
C2—C3—C4—C51.7 (5)C4—C3—C8—C9117.0 (3)
C8—C3—C4—C5178.2 (3)C2—C3—C8—C1062.1 (3)
C3—C4—C5—C60.5 (5)C4—C3—C8—C10117.9 (3)
Symmetry code: (i) x+1, y, z.

Experimental details

(Ia)(Ib)
Crystal data
Chemical formula[Cu(C10H11O2)2][Cu(C10H11O2)2]
Mr389.92389.92
Crystal system, space groupTriclinic, P1Monoclinic, P21/c
Temperature (K)298200
a, b, c (Å)5.1549 (3), 6.9872 (4), 13.9097 (8)8.7410 (2), 6.7470 (1), 15.3448 (4)
α, β, γ (°)77.747 (3), 84.255 (3), 70.508 (3)90, 100.800 (1), 90
V3)461.30 (5)888.94 (3)
Z12
Radiation typeMo KαMo Kα
µ (mm1)1.201.25
Crystal size (mm)0.29 × 0.08 × 0.040.22 × 0.12 × 0.05
Data collection
DiffractometerNonius KappaCCD
diffractometer
Nonius KappaCCD
diffractometer
Absorption correctionGaussian
SHELXTL (Sheldrick, 1996)
Gaussian
SHELXTL (Sheldrick, 1996)
Tmin, Tmax0.786, 0.9550.794, 0.948
No. of measured, independent and
observed [I > 2σ(I)] reflections
6146, 2096, 1541 23670, 2040, 1591
Rint0.0640.076
(sin θ/λ)max1)0.6490.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.107, 1.07 0.048, 0.112, 1.12
No. of reflections20952040
No. of parameters118117
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.27, 0.510.70, 0.83

Computer programs: COLLECT (Nonius, 1998), DENZO–SMN (Otwinowski & Minor, 1997), DENZO–SMN and SHELXTL (Sheldrick, 1996), SHELXS86 (Sheldrick, 1990), SHELXTL.

Selected Distances (Å) and Angles (°) top
IaaIbaIcb
Cu1-O11.915 (2)1.918 (2)1.900 (2)
Cu1-O21.901 (2)1.913 (2)1.904 (2)
O1-C11.295 (3)1.292 (3)1.296 (5)
O2-C71.289 (4)1.293 (3)1.293 (5)
O1-Cu1-O283.70 (9)83.90 (8)83.84 (13)
Cu1-O1-C1113.0 (2)112.9 (2)113.5 (3)
Cu1-O2-C7113.5 (2)112.7 (2)113.5 (3)
Notes: (a) this work; (b) Barret et al. (2002);
 

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