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Acta Crystallogr Sect E Struct Rep Online. 2010 December 1; 66(Pt 12): m1508.
Published online 2010 November 6. doi:  10.1107/S1600536810043503
PMCID: PMC3011584

Bis[2-(methyl­amino)­troponato]copper(II)

Abstract

In the title compound, [Cu(C8H8NO)2], a strictly square-planar geometry about the CuII metal atom is observed. Substitution of an O atom with a methyl-functionalized N atom does not significantly alter the bond distances and angles in the copper(II) complex when compared with a similar bis­(troponato)copper(II) complex. π–π stacking is observed between the tropolone rings, with inter­planar distances of 3.5039 (16) and 3.2933 (15) Å, respectively. Additional stabilisation of the structure is accomplished through C—H(...)O hydrogen-bonding interactions.

Related literature

For related literature on values of bond lengths and angles, see: Zhang et al. (2008 [triangle]); Hill & Steyl (2008 [triangle]); Kristiansson (2002 [triangle]). For similar structures, see: Liang et al. (2001 [triangle]). For other related structures, see: Starikova & Shugam (1969 [triangle]); Byrn et al. (1993 [triangle]); Park & Marshall (2005 [triangle]); Dessy & Fares (1979 [triangle]); Baidina et al. (2004 [triangle]). For the synthesis of the title compound, see: Roesky & Burgstein (1999 [triangle]); Claramunt et al. (2004 [triangle]). For background and the use of the title compound, see: Roesky (2000 [triangle]); Nepveu et al. (1993 [triangle]); Crous et al. (2005 [triangle]); Roodt et al. (2003 [triangle]); Steyl (2005 [triangle]); Steyl et al. (2001 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-m1508-scheme1.jpg

Experimental

Crystal data

  • [Cu(C8H8NO)2]
  • M r = 331.85
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-m1508-efi1.jpg
  • a = 6.7541 (9) Å
  • b = 9.1599 (12) Å
  • c = 22.084 (3) Å
  • β = 92.108 (5)°
  • V = 1365.3 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 1.61 mm−1
  • T = 100 K
  • 0.34 × 0.32 × 0.17 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2004 [triangle]) T min = 0.583, T max = 0.760
  • 21665 measured reflections
  • 2985 independent reflections
  • 2804 reflections with I > 2σ(I)
  • R int = 0.032

Refinement

  • R[F 2 > 2σ(F 2)] = 0.022
  • wR(F 2) = 0.066
  • S = 1.06
  • 2985 reflections
  • 190 parameters
  • H-atom parameters constrained
  • Δρmax = 0.36 e Å−3
  • Δρmin = −0.38 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT-Plus (Bruker, 2004 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: DIAMOND (Brandenberg & Putz, 2004 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810043503/pk2271sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810043503/pk2271Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The University of the Free State is gratefully acknowledged for financial support, and Leo Kirsten for the data collection.

supplementary crystallographic information

Comment

Complexes containing tropolonato type derivatives have steadily increased over the last few decades (Roesky, 2000), with most of the work having involved the first and second row transition elements. This attention has been to a large extent due to the medical application of tropolone in radio-pharmaceuticals (Nepveu et al., 1993) and catalyst precursors (Crous et al., 2005; Roodt et al., 2003). Functionalization of the tropolonato backbone (seven-membered ring) has also been investigated with a range of RhI and PdII complexes reported to date (Steyl et al., 2001; Steyl, 2005).

Heteroatom substitution of the tropolonato moiety has also been reported, most notably the O atoms are replaced with functionalized amino groups, resulting in either the 2- (aminotropone) or 1,2- (aminotropoimine) compounds (Roesky & Burgstein, 1999; Claramunt et al., 2004). Thus, a host of amino and anilino derivatives of tropolone have been reported (Roesky & Burgstein, 1999; Roesky, 2000; Claramunt et al., 2004). The addition of electron-donating or -withdrawing moieties to the N atom can significantly increase the application of these compounds in coordination chemistry. The most interesting observation concerning the CuII metal centres in general is the difference in the coordination behaviour of the bidentate-O,O donor atoms compared to the N,N donor atom complexes; the geometrical conformation changes from a square planar (Starikova & Shugam, 1969; Byrn et al., 1993) to a tetrahedral geometry (Park & Marshall, 2005; Dessy & Fares, 1979), respectively. The N-methylaminoacetylacetonato derivative have been reported (Baidina et al., 2004) as a distorted tetrahedral complex.

In an effort to further investigate these types of complexes, the crystal structure of [Cu(TropNMe)2] is presented.

The copper(II) ion is coordinated by two TropNMe ligands in a square-planar geometry (Fig 1). The Cu2+ ion chelates the TropNMe ligand via N1 and O1 to form a five-membered ring. The N1—O1—Cu—N2—O2 moiety is strictly planar. The ligand planes form angles of 6.54 (1)° and 3.12 (1)°, respectively with the 5-membered ring. This compares with literature (Hill & Steyl, 2008). π–π stacking between C11–C17 and C11–C17i (-x, 1 - y, -z) as well as C11–C17 and C21–C27ii (-x, 2 - y, -z) with intercentroid distances of 4.1483 (4) Å and 3.7827 (4) Å respectively as defined by the seven-membered ring system. Cu—O1 and Cu—O2 bond distances is 1.9313 (2) Å and 1.9386 (2) Å, respectively. This correlates well with literature (Zhang et al., 2008). The Cu—N1 and Cu—N2 bond distances is 1.9276 (2) Å and 1.9291 (2) Å respectively. The O1—Cu—N1 and O2—Cu—N2 angles is 82.292 (4)° and 82.090 (4)° respectively. This correlates well with literature (Kristiansson 2002). The N1—Cu—N2 angle is 175.769 (5)° this is smaller than the O1—Cu—O2 angle, which is 179.229 (6)°. This is in accordance with literature (Liang et al., 2001). The title compound is further stabilized by weak intramolecular C15—H15A···O1 and C16—H16A···O2 hydrogen interactions.

Experimental

Synthesis of 2-(N-methylamino)tropone (HTropNMe) was done according to the literature procedure (Roesky & Burgstein, 1999; Claramunt et al., 2004), while all other starting materials were obtained from commercially available sources. Cu(NO3)2 (100 mg, 0.44 mmol) was dissolved in CHCl3 or MeOH and refluxed with HTropNMe for 30 min. The product was filtered from the cold solution and dried in air for 24 h. Rhombic dark-green crystals suitable for X-ray diffraction was obtained from a chloroform/ether (1:1, 10 ml) mixture after 2 d. (Yield: 117 mg, 70%) 1H NMR (300 MHz, CDCl3, 25°C) 7.32 (m, 2H), 7.12 (d, 1H), 6.95 (d, 1H), 6.81 (t, 1H), 1.56 (s, 3H)

Refinement

All H atoms were positioned geometrically and allowed to ride on their parent atoms, with Uiso(H) = 1.2Ueq(parent) of the parent atom with a C—H distance of 0.93. The methyl H atoms were placed in geometrically idealized positions and constrained to ride on the parent atoms with Uiso(H) = 1.5Ueq(C) and at a distance of 0.96 Å.

Figures

Fig. 1.
Representation of the title compound, showing the numbering scheme and displacement ellipsoids (50% probability).

Crystal data

[Cu(C8H8NO)2]F(000) = 684
Mr = 331.85Dx = 1.614 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 6754 reflections
a = 6.7541 (9) Åθ = 2.4–28.2°
b = 9.1599 (12) ŵ = 1.61 mm1
c = 22.084 (3) ÅT = 100 K
β = 92.108 (5)°Cuboid, black
V = 1365.3 (3) Å30.34 × 0.32 × 0.17 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer2985 independent reflections
graphite2804 reflections with I > 2σ(I)
Detector resolution: 8.5 pixels mm-1Rint = 0.032
[var phi] and ω scansθmax = 27.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2004)h = −8→8
Tmin = 0.583, Tmax = 0.760k = −10→11
21665 measured reflectionsl = −28→28

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.022Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.066H-atom parameters constrained
S = 1.06w = 1/[σ2(Fo2) + (0.0363P)2 + 0.8483P] where P = (Fo2 + 2Fc2)/3
2985 reflections(Δ/σ)max < 0.001
190 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = −0.38 e Å3

Special details

Experimental. First 80 frames repeated after collection for monitoring possible decay.
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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)

xyzUiso*/Ueq
C110.0756 (2)0.73761 (16)−0.03802 (6)0.0123 (3)
C12−0.1170 (2)0.68077 (16)−0.01916 (6)0.0117 (3)
C13−0.2292 (2)0.57152 (18)−0.05113 (7)0.0152 (3)
H13−0.35150.5479−0.03360.018*
C14−0.1913 (2)0.49449 (18)−0.10280 (7)0.0172 (3)
H14−0.29070.4259−0.11470.021*
C15−0.0299 (2)0.50069 (18)−0.14071 (7)0.0171 (3)
H15−0.03260.4366−0.17460.02*
C160.1324 (2)0.59075 (18)−0.13361 (7)0.0157 (3)
H160.22820.5813−0.16380.019*
C170.1773 (2)0.69413 (17)−0.08858 (7)0.0141 (3)
H170.29930.7436−0.09340.017*
C18−0.3658 (2)0.70243 (17)0.05564 (6)0.0136 (3)
H18A−0.38730.75930.09240.02*
H18B−0.3640.59820.06560.02*
H18C−0.47320.72210.02570.02*
C21−0.0559 (2)1.02279 (16)0.17475 (6)0.0119 (3)
C220.1447 (2)1.06912 (16)0.15765 (6)0.0113 (3)
C230.2695 (2)1.16602 (17)0.19214 (7)0.0145 (3)
H230.39881.17730.17730.017*
C240.2340 (2)1.24600 (17)0.24341 (7)0.0172 (3)
H240.34221.30420.25780.021*
C250.0645 (2)1.25541 (17)0.27773 (7)0.0176 (3)
H250.06931.32190.31080.021*
C26−0.1089 (2)1.17780 (18)0.26841 (7)0.0167 (3)
H26−0.20941.19810.29620.02*
C27−0.1587 (2)1.07348 (18)0.22402 (7)0.0146 (3)
H27−0.28481.02960.22830.018*
C280.3903 (2)1.04390 (17)0.08191 (7)0.0136 (3)
H28A0.40640.98960.04420.02*
H28B0.49661.01710.11120.02*
H28C0.39651.14890.07370.02*
N1−0.17729 (18)0.74362 (14)0.03074 (5)0.0117 (2)
N20.19904 (18)1.00838 (14)0.10669 (5)0.0117 (2)
O10.15352 (16)0.83831 (13)−0.00342 (5)0.0158 (2)
O2−0.14060 (15)0.92738 (13)0.13907 (5)0.0142 (2)
Cu0.00529 (2)0.881953 (19)0.067482 (7)0.01073 (8)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C110.0124 (7)0.0115 (7)0.0126 (6)0.0001 (5)−0.0022 (5)0.0015 (5)
C120.0118 (7)0.0108 (7)0.0122 (6)0.0004 (5)−0.0013 (5)0.0018 (5)
C130.0146 (7)0.0149 (8)0.0161 (7)−0.0032 (6)0.0009 (5)−0.0008 (6)
C140.0190 (7)0.0146 (8)0.0178 (7)−0.0037 (6)−0.0027 (6)−0.0030 (6)
C150.0222 (8)0.0142 (8)0.0147 (7)0.0012 (6)−0.0007 (6)−0.0048 (6)
C160.0183 (7)0.0160 (8)0.0128 (7)0.0034 (6)0.0016 (6)−0.0005 (6)
C170.0137 (7)0.0136 (8)0.0150 (7)−0.0007 (6)0.0004 (5)0.0005 (5)
C180.0122 (7)0.0146 (8)0.0142 (7)−0.0020 (6)0.0019 (5)−0.0006 (5)
C210.0135 (7)0.0103 (7)0.0116 (6)0.0000 (5)−0.0024 (5)0.0028 (5)
C220.0120 (7)0.0094 (7)0.0123 (6)0.0013 (5)−0.0016 (5)0.0024 (5)
C230.0134 (7)0.0143 (8)0.0158 (7)−0.0009 (6)−0.0013 (5)0.0000 (6)
C240.0210 (8)0.0134 (8)0.0166 (7)−0.0028 (6)−0.0048 (6)−0.0014 (6)
C250.0274 (8)0.0133 (8)0.0120 (7)−0.0008 (6)−0.0006 (6)−0.0026 (5)
C260.0224 (8)0.0162 (8)0.0118 (7)0.0015 (6)0.0030 (6)0.0001 (6)
C270.0160 (7)0.0150 (8)0.0128 (7)−0.0010 (6)0.0006 (5)0.0017 (6)
C280.0106 (7)0.0151 (8)0.0152 (7)−0.0013 (5)0.0006 (5)−0.0007 (5)
N10.0115 (6)0.0115 (6)0.0122 (6)−0.0012 (5)0.0000 (4)0.0008 (5)
N20.0114 (6)0.0110 (6)0.0127 (6)−0.0007 (5)−0.0011 (4)−0.0003 (5)
O10.0145 (5)0.0185 (6)0.0143 (5)−0.0058 (4)0.0019 (4)−0.0048 (4)
O20.0137 (5)0.0167 (6)0.0123 (5)−0.0035 (4)0.0008 (4)−0.0027 (4)
Cu0.01051 (11)0.01176 (12)0.00990 (11)−0.00228 (6)−0.00007 (7)−0.00182 (6)

Geometric parameters (Å, °)

C11—O11.2970 (18)C21—C221.482 (2)
C11—C171.390 (2)C22—N21.3196 (19)
C11—C121.475 (2)C22—C231.425 (2)
C12—N11.3210 (19)C23—C241.377 (2)
C12—C131.426 (2)C23—H230.95
C13—C141.374 (2)C24—C251.399 (2)
C13—H130.95C24—H240.95
C14—C151.400 (2)C25—C261.379 (2)
C14—H140.95C25—H250.95
C15—C161.376 (2)C26—C271.401 (2)
C15—H150.95C26—H260.95
C16—C171.398 (2)C27—H270.95
C16—H160.95C28—N21.4582 (18)
C17—H170.95C28—H28A0.98
C18—N11.4551 (18)C28—H28B0.98
C18—H18A0.98C28—H28C0.98
C18—H18B0.98N1—Cu1.9263 (12)
C18—H18C0.98N2—Cu1.9287 (12)
C21—O21.2958 (18)O1—Cu1.9312 (11)
C21—C271.392 (2)O2—Cu1.9385 (11)
O1—C11—C17118.36 (13)C24—C23—H23114.6
O1—C11—C12115.32 (13)C22—C23—H23114.6
C17—C11—C12126.32 (14)C23—C24—C25130.46 (15)
N1—C12—C13122.96 (13)C23—C24—H24114.8
N1—C12—C11112.57 (13)C25—C24—H24114.8
C13—C12—C11124.46 (13)C26—C25—C24126.51 (15)
C14—C13—C12131.26 (14)C26—C25—H25116.7
C14—C13—H13114.4C24—C25—H25116.7
C12—C13—H13114.4C25—C26—C27129.55 (15)
C13—C14—C15130.47 (15)C25—C26—H26115.2
C13—C14—H14114.8C27—C26—H26115.2
C15—C14—H14114.8C21—C27—C26131.35 (15)
C16—C15—C14126.19 (15)C21—C27—H27114.3
C16—C15—H15116.9C26—C27—H27114.3
C14—C15—H15116.9N2—C28—H28A109.5
C15—C16—C17129.65 (15)N2—C28—H28B109.5
C15—C16—H16115.2H28A—C28—H28B109.5
C17—C16—H16115.2N2—C28—H28C109.5
C11—C17—C16131.64 (15)H28A—C28—H28C109.5
C11—C17—H17114.2H28B—C28—H28C109.5
C16—C17—H17114.2C12—N1—C18120.21 (12)
N1—C18—H18A109.5C12—N1—Cu115.20 (10)
N1—C18—H18B109.5C18—N1—Cu124.54 (10)
H18A—C18—H18B109.5C22—N2—C28120.26 (12)
N1—C18—H18C109.5C22—N2—Cu115.52 (10)
H18A—C18—H18C109.5C28—N2—Cu124.15 (10)
H18B—C18—H18C109.5C11—O1—Cu114.43 (9)
O2—C21—C27118.58 (13)C21—O2—Cu114.48 (9)
O2—C21—C22115.20 (13)N1—Cu—N2175.77 (5)
C27—C21—C22126.21 (14)N1—Cu—O182.26 (5)
N2—C22—C23122.75 (13)N2—Cu—O197.17 (5)
N2—C22—C21112.46 (13)N1—Cu—O298.51 (5)
C23—C22—C21124.78 (13)N2—Cu—O282.06 (5)
C24—C23—C22130.81 (14)O1—Cu—O2179.23 (4)
O1—C11—C12—N1−0.08 (18)C13—C12—N1—C180.0 (2)
C17—C11—C12—N1−179.70 (14)C11—C12—N1—C18179.21 (12)
O1—C11—C12—C13179.09 (14)C13—C12—N1—Cu177.49 (11)
C17—C11—C12—C13−0.5 (2)C11—C12—N1—Cu−3.32 (16)
N1—C12—C13—C14−179.73 (16)C23—C22—N2—C28−2.6 (2)
C11—C12—C13—C141.2 (3)C21—C22—N2—C28178.48 (12)
C12—C13—C14—C15−0.7 (3)C23—C22—N2—Cu−179.61 (11)
C13—C14—C15—C16−0.3 (3)C21—C22—N2—Cu1.49 (16)
C14—C15—C16—C170.5 (3)C17—C11—O1—Cu−176.94 (11)
O1—C11—C17—C16−179.83 (16)C12—C11—O1—Cu3.41 (16)
C12—C11—C17—C16−0.2 (3)C27—C21—O2—Cu173.51 (11)
C15—C16—C17—C110.1 (3)C22—C21—O2—Cu−5.60 (16)
O2—C21—C22—N22.74 (18)C12—N1—Cu—O14.09 (10)
C27—C21—C22—N2−176.28 (14)C18—N1—Cu—O1−178.57 (12)
O2—C21—C22—C23−176.13 (14)C12—N1—Cu—O2−175.85 (10)
C27—C21—C22—C234.8 (2)C18—N1—Cu—O21.49 (12)
N2—C22—C23—C24175.20 (16)C22—N2—Cu—O1176.53 (11)
C21—C22—C23—C24−6.0 (3)C28—N2—Cu—O1−0.34 (12)
C22—C23—C24—C250.7 (3)C22—N2—Cu—O2−3.48 (11)
C23—C24—C25—C263.1 (3)C28—N2—Cu—O2179.66 (12)
C24—C25—C26—C270.0 (3)C11—O1—Cu—N1−4.09 (10)
O2—C21—C27—C26−177.74 (16)C11—O1—Cu—N2171.68 (10)
C22—C21—C27—C261.3 (3)C21—O2—Cu—N1−179.20 (10)
C25—C26—C27—C21−4.0 (3)C21—O2—Cu—N25.04 (10)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C18—H18A···O20.982.473.1222 (18)124
C28—H28A···O10.982.413.0715 (18)124

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2271).

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