supplementary materials


br2212 scheme

Acta Cryst. (2012). E68, m1377-m1378    [ doi:10.1107/S1600536812042699 ]

Bis(acetato-[kappa]2O,O')(4,4'-dimethyl-2,2'-bipyridine-[kappa]2N,N')zinc

M. A. Harvey, S. A. Suarez, A. Ibañez, F. Doctorovich and R. Baggio

Abstract top

The molecular structure of the title compound, [Zn(CH3COO)2(C12H12N2)], consists of isolated molecules bisected by a twofold rotation axis which goes through the ZnII cation and halves the organic base through the central C-C bond. The ZnII ion is coordinated by two N atoms from one molecule of the aromatic base and four O atoms from two bidentate, symmetry-related acetate anions, which coordinate asymmetrically [Zn-O distances of 2.058 (2) and 2.362 (3) Å], while the two Zn-N bond distances are equal as imposed by symmetry [2.079 (2) Å]. The crystal structure is supported by a number of weak C-H...O interactions and C-H...[pi] contacts, with no [pi]-[pi] interactions present, mainly hindered by the substituent methyl groups and the relative molecular orientation. The result is a three-dimensional structure in which each molecule is linked to eight different neighbors.

Comment top

Polypyridil compounds and some of their derivatives have shown to be fruitful ligands in supramolecular photochemistry, due to the capability of its extended π- systems to absorb light. They can act as light harvesters as much as to relax photoexcited metal centres via MLCT to the ligand-centred π*L orbital; some interesting examples can be found in Steed & Atwood, 2009. In particular, in the case of 4,4'-dimethyl-2,2'-bipyridine (dmbp), the presence of the methyl groups in the aromatic ligand can additionally influence the structural behavior when binding to a metal centre. We present in what follows the crystal and molecular structure of the title compound, C16H18N2O4Zn, consisting of isolated Zn(dmbp)(ac)2, molecules (ac = acetate) bisected by a twofold axis which goes through the Zn(II) cation and halves the organic base through the central C—C bond.

The Zn(II) ion is coordinated by two nitrogen atoms from one molecule of the aromatic base and four oxygen atoms from two bidentate, symmetry related acetate anions (Fig. 1). A very similar compound, with Cu(II) as its central cation has been reported in Barquín et al., 2010. Donor atoms in the title compound can not fit in any regular polyhedron, but the three chelate ligands fulfill the vector bond valence postulate of the Vectorial Bond-Valence Model (for details on the theory see Harvey et al., 2006). The three ligand vectors, as defined therein, lay in a planar trigonal geometry with a sum of angles equal to 359.6 (2)° (ideal: 360°) and a resultant vector modulus of 0.03 v.u. (Ideal: 0.00 v.u.).

Both acetate anions coordinate asymmetrically (Zn—O distances 2.058 (2) and 2.362 (3) Å), while the two Zn—N bond distances are equal (2.079 (2) Å) as imposed by symmetry.

The crystal structure is supported by a number of weak C—H···O interactions (Table 1, entries 1,2) and C—H···π contacts (Table 1, entries 3 to 5). In spite of the presence of aromatic rings there are no π-π interactions in the structure, mainly hindered by the substituent methyl groups and the relative molecular orientation.

The overall effect of these weak interactions, uniformly distributed in space, is the formation of a three-dimensional structure where each molecule is linked to eight different neighbors. Fig. 2 presents a highly simplified packing view projected down c, where only the C—H···O bonds have been drawn, for clarity, and where the complex linkage can be envisaged.

Related literature top

For properties of polypyridyl compounds, see Steed & Atwood (2009). For related structures, see: Barquín et al. (2010). For details of the vectorial bond–valence model, see Harvey et al. (2006).

Experimental top

The title compound was obtained as an unexpected byproduct in an attempt to synthesize a Zn tetrathionate complex with the aromatic base. Solid Zn acetate dihydrate, 4,4'-Dimethylbipyridine and potassium tetrathionate, 0.050 mmol of each, were added to 5 ml of dimethylformamide. On standing, colorless blocks of the title compound could be extracted for diffraction experiments.

Refinement top

All H atoms were confirmed in a difference map, further idealized and allowed to ride, with displacement parameters taken as Uiso(H) = X × Ueq(C) [(C—H) methyl = 0.96 A°, X = 1.5; (C—H) arom = 0.93 A°, X = 1.2] (CH3 groups were also free to rotate as well).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Ellipsoid plot of (I), drawn with displacement factors at a 40% probability level. In full(empty) ellipsods and bonds, the independent(symmetry related) part of the structure. Symmetry code: (v): -x, -y, z
[Figure 2] Fig. 2. Packing view projected down c. Only the C—H···O interactions have been drawn (in broken lines). H atoms not invovled in these interactions have been omitted, for clarity. Symmetry codes: (i) x + 1/4, -y + 1/4, z + 1/4; (ii) -x, -y, z + 1.
Bis(acetato-κ2O,O')(4,4'-dimethyl-2,2'-bipyridine- κ2N,N')zinc top
Crystal data top
[Zn(C2H3O2)2(C12H12N2)]F(000) = 1520
Mr = 367.71Dx = 1.461 Mg m3
Orthorhombic, Fdd2Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2dCell parameters from 1985 reflections
a = 14.4779 (5) Åθ = 3.6–28.9°
b = 28.5700 (15) ŵ = 1.49 mm1
c = 8.0854 (3) ÅT = 295 K
V = 3344.4 (2) Å3Prism, white
Z = 80.3 × 0.3 × 0.2 mm
Data collection top
Oxford Diffraction Gemini CCD S Ultra
diffractometer
1481 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
ω scans, thick slicesθmax = 29.0°, θmin = 3.6°
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2009)
h = 1718
Tmin = 0.65, Tmax = 0.75k = 3717
3945 measured reflectionsl = 105
1563 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.026H-atom parameters constrained
wR(F2) = 0.068 w = 1/[σ2(Fo2) + (0.0402P)2 + 1.025P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
1563 reflectionsΔρmax = 0.28 e Å3
107 parametersΔρmin = 0.26 e Å3
1 restraintAbsolute structure: Flack (1983), 374 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.010 (16)
Crystal data top
[Zn(C2H3O2)2(C12H12N2)]V = 3344.4 (2) Å3
Mr = 367.71Z = 8
Orthorhombic, Fdd2Mo Kα radiation
a = 14.4779 (5) ŵ = 1.49 mm1
b = 28.5700 (15) ÅT = 295 K
c = 8.0854 (3) Å0.3 × 0.3 × 0.2 mm
Data collection top
Oxford Diffraction Gemini CCD S Ultra
diffractometer
1563 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2009)
1481 reflections with I > 2σ(I)
Tmin = 0.65, Tmax = 0.75Rint = 0.015
3945 measured reflectionsθmax = 29.0°
Refinement top
R[F2 > 2σ(F2)] = 0.026H-atom parameters constrained
wR(F2) = 0.068Δρmax = 0.28 e Å3
S = 1.09Δρmin = 0.26 e Å3
1563 reflectionsAbsolute structure: Flack (1983), 374 Friedel pairs
107 parametersFlack parameter: 0.010 (16)
1 restraint
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.

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 > σ(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) top
xyzUiso*/Ueq
Zn1000.08552 (5)0.04845 (13)
O10.10026 (14)0.03972 (8)0.0279 (3)0.0745 (6)
N10.02563 (14)0.04418 (7)0.2846 (2)0.0456 (4)
O20.12535 (18)0.03328 (9)0.0599 (3)0.0843 (7)
C40.01794 (12)0.05180 (7)0.5779 (5)0.0421 (5)
H40.00710.0380.68030.051*
C70.14861 (19)0.00731 (10)0.0837 (4)0.0548 (7)
C50.01168 (12)0.02544 (8)0.4354 (3)0.0361 (4)
C80.2331 (2)0.01806 (14)0.1800 (9)0.0900 (14)
H8B0.27770.03280.10930.135*
H8C0.25840.01040.22380.135*
H8A0.21780.03880.26940.135*
C30.04052 (15)0.09917 (8)0.5683 (4)0.0502 (5)
C10.0483 (2)0.08971 (10)0.2769 (4)0.0604 (7)
H10.05860.1030.17350.073*
C20.05697 (19)0.11722 (9)0.4128 (4)0.0607 (7)
H20.07410.14840.4010.073*
C60.0449 (2)0.12828 (10)0.7225 (4)0.0719 (9)
H6A0.07210.11030.81010.108*
H6C0.01640.13760.75380.108*
H6B0.08180.15560.70240.108*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.04289 (17)0.0737 (3)0.02871 (17)0.01368 (17)00
O10.0622 (11)0.0907 (14)0.0706 (15)0.0028 (10)0.0158 (11)0.0093 (12)
N10.0478 (10)0.0549 (11)0.0342 (11)0.0047 (8)0.0032 (8)0.0080 (8)
O20.0909 (16)0.0871 (15)0.0749 (17)0.0313 (12)0.0146 (13)0.0022 (13)
C40.0424 (11)0.0480 (10)0.0361 (11)0.0034 (8)0.0042 (16)0.0013 (12)
C70.0399 (12)0.0850 (19)0.0393 (14)0.0085 (11)0.0013 (10)0.0056 (13)
C50.0329 (9)0.0459 (12)0.0296 (11)0.0036 (7)0.0017 (8)0.0031 (9)
C80.061 (2)0.109 (3)0.100 (4)0.0012 (17)0.037 (3)0.017 (3)
C30.0452 (10)0.0462 (11)0.0593 (16)0.0006 (9)0.0095 (12)0.0025 (12)
C10.0654 (15)0.0602 (15)0.0557 (18)0.0014 (12)0.0060 (12)0.0240 (13)
C20.0621 (16)0.0440 (12)0.076 (2)0.0032 (11)0.0005 (14)0.0087 (14)
C60.080 (2)0.0559 (15)0.079 (2)0.0007 (14)0.0190 (17)0.0158 (16)
Geometric parameters (Å, º) top
Zn1—O1i2.058 (2)C4—H40.93
Zn1—O12.058 (2)C7—C81.482 (5)
Zn1—N12.079 (2)C5—C5i1.493 (4)
Zn1—N1i2.079 (2)C8—H8B0.96
Zn1—O22.362 (3)C8—H8C0.96
Zn1—O2i2.362 (3)C8—H8A0.96
Zn1—C72.558 (3)C3—C21.380 (4)
Zn1—C7i2.558 (3)C3—C61.500 (4)
O1—C71.246 (3)C1—C21.357 (4)
N1—C11.343 (3)C1—H10.93
N1—C51.347 (3)C2—H20.93
O2—C71.223 (3)C6—H6A0.96
C4—C51.380 (4)C6—H6C0.96
C4—C31.394 (3)C6—H6B0.96
O1i—Zn1—O1127.09 (15)C5—C4—C3119.9 (3)
O1i—Zn1—N1123.63 (9)C5—C4—H4120
O1—Zn1—N197.82 (8)C3—C4—H4120
O1i—Zn1—N1i97.82 (8)O2—C7—O1119.6 (3)
O1—Zn1—N1i123.63 (9)O2—C7—C8120.4 (3)
N1—Zn1—N1i78.52 (11)O1—C7—C8120.0 (3)
O1i—Zn1—O295.63 (10)O2—C7—Zn166.85 (17)
O1—Zn1—O257.21 (9)O1—C7—Zn152.72 (15)
N1—Zn1—O2140.08 (8)C8—C7—Zn1172.7 (2)
N1i—Zn1—O290.22 (9)N1—C5—C4122.0 (2)
O1i—Zn1—O2i57.21 (9)N1—C5—C5i114.92 (13)
O1—Zn1—O2i95.63 (10)C4—C5—C5i123.13 (15)
N1—Zn1—O2i90.22 (9)C7—C8—H8B109.5
N1i—Zn1—O2i140.08 (8)C7—C8—H8C109.5
O2—Zn1—O2i120.30 (15)H8B—C8—H8C109.5
O1i—Zn1—C7113.57 (9)C7—C8—H8A109.5
O1—Zn1—C728.79 (8)H8B—C8—H8A109.5
N1—Zn1—C7120.97 (8)H8C—C8—H8A109.5
N1i—Zn1—C7108.27 (9)C2—C3—C4117.0 (3)
O2—Zn1—C728.42 (8)C2—C3—C6122.9 (2)
O2i—Zn1—C7110.31 (10)C4—C3—C6120.1 (3)
O1i—Zn1—C7i28.79 (8)N1—C1—C2123.1 (2)
O1—Zn1—C7i113.57 (9)N1—C1—H1118.5
N1—Zn1—C7i108.27 (9)C2—C1—H1118.5
N1i—Zn1—C7i120.97 (8)C1—C2—C3120.4 (2)
O2—Zn1—C7i110.31 (10)C1—C2—H2119.8
O2i—Zn1—C7i28.42 (8)C3—C2—H2119.8
C7—Zn1—C7i115.34 (13)C3—C6—H6A109.5
C7—O1—Zn198.50 (18)C3—C6—H6C109.5
C1—N1—C5117.6 (2)H6A—C6—H6C109.5
C1—N1—Zn1126.56 (18)C3—C6—H6B109.5
C5—N1—Zn1115.64 (15)H6A—C6—H6B109.5
C7—O2—Zn184.73 (19)H6C—C6—H6B109.5
Symmetry code: (i) x, y, z.
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the Zn1,O1,C7,O2 and N1,C1–C5 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C2—H2···O1ii0.932.533.354 (4)147
C6—H6A···O2iii0.962.563.438 (4)153
C4—H4···Cg1iv0.932.993.874 (4)160
C4—H4···Cg1iii0.932.963.766 (4)145
C8—H8B···Cg2v0.962.963.804 (4)147
Symmetry codes: (ii) x+1/4, y+1/4, z+1/4; (iii) x, y, z+1; (iv) x, y, z+1; (v) x1/2, y, z1/2.
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the Zn1,O1,C7,O2 and N1,C1–C5 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C2—H2···O1i0.932.533.354 (4)147
C6—H6A···O2ii0.962.563.438 (4)153
C4—H4···Cg1iii0.932.993.874 (4)160
C4—H4···Cg1ii0.932.963.766 (4)145
C8—H8B···Cg2iv0.962.963.804 (4)147
Symmetry codes: (i) x+1/4, y+1/4, z+1/4; (ii) x, y, z+1; (iii) x, y, z+1; (iv) x1/2, y, z1/2.
Acknowledgements top

We would like to thank the Spanish Research Council (CSIC) for providing us with a free-of charge licence to the CSD System (Allen, 2002). FONCyT grant PME-01113 (XRD) is gratefully acknowledged.

references
References top

Allen, F. H. (2002). Acta Cryst. B58, 380–388.

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Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Harvey, M. A., Baggio, S. & Baggio, R. (2006). Acta Cryst. B62, 1038–1042.

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Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Steed, J. W. & Atwood, J. L. (2009). Supramolecular Chemistry, 2nd. ed., pp. 710–718. New York: John Wiley & Sons.