Acta Cryst. (2009). E65, m1421 [ doi:10.1107/S1600536809041336 ]
The title compound, [Zn(C6H5S)2(C18H12N2)], was prepared as a model for future complexes that will be incorporated into light-harvesting arrays. The ZnII atom lies on a twofold rotation axis and the ligands are arranged tetrahedrally around this atom. The benzenethiolate ligand and the biquinoline ligand are nearly perpendicular to one another, making a dihedral angle of 84.09 (5)°. The biquinoline ligand is nearly planar, with a maximum deviation of 0.055 (3) Å from the mean plane of the ring system. In the crystal, the molecules pack in a manner such that the biquinoline ligands are parallel to one another, with a ![[pi]](/logos/entities/pi_rmgif.gif)
- interaction [interplanar distance = 3.38 (1) Å] with the neighboring biquinoline ligand.
The complex was synthesized via a general procedure (Crosby et al., 1985). Zn(OAc)2.2H2O (0.0566 g) was dissolved in 5 ml absolute ethanol and heated. benzenethiol (0.0582 g) was dissolved in 4 ml absolute ethanol and heated. The benzenethiol solution was then added dropwise to the zinc(II) solution with vigorous stirring at reflux. 2,2'-biquinoline (0.0640 g) dissolved in 5 ml absolute ethanol was then slowly added to the refluxing solution. The solution turned orange and was allowed to sit overnight. An orange crystalline solid (0.0848 g) was collected in 47% yield via vacuum filtration and washed with cold ethanol. The compound was characterized by 1H NMR, UV-VIS absorption spectroscopy, and room temperature and 77 K emission spectroscopy.
The H-atoms were included in calculated positions and treated as riding atoms: C—H = 0.93 Å, with Uiso(H) = 1.2Ueq(parent C-atom).
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: DIRDIF (Beurskens et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./su2141fig1thm.gif)
| Fig. 1. View of the molecular structure of the title compound, with 50% probability displacement ellipsoids [Symmetry code: (i) -x, y, -z + 3/2] |
![[Figure 2]](./su2141fig2thm.gif)
| Fig. 2. Crystal packing diagram of the title compound, showing the π-π interactions between the biquinoline ligands. |
| [Zn(C6H5S)2(C18H12N2)] | F(000) = 1112 |
| Mr = 539.99 | Dx = 1.414 Mg m−3 |
| Monoclinic, C2/c | Cu Kα radiation, λ = 1.54184 Å |
| Hall symbol: -C 2yc | Cell parameters from 25 reflections |
| a = 17.141 (2) Å | θ = 9.8–42.1° |
| b = 11.5591 (8) Å | µ = 3.04 mm−1 |
| c = 12.8318 (14) Å | T = 295 K |
| β = 93.811 (10)° | Prism, orange |
| V = 2536.8 (4) Å3 | 0.30 × 0.19 × 0.11 mm |
| Z = 4 |
| Enraf–Nonius CAD-4 diffractometer | Rint = 0.025 |
| Non–profiled ω/2θ scans | θmax = 67.5°, θmin = 4.6° |
| Absorption correction: analytical (Alcock, 1970) | h = −20→20 |
| Tmin = 0.531, Tmax = 0.796 | k = −13→0 |
| 4580 measured reflections | l = −15→15 |
| 2294 independent reflections | 3 standard reflections every 195 reflections |
| 1821 reflections with I > 2σ(I) | intensity decay: 6% |
| Refinement on F2 | H-atom parameters constrained |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0413P)2 + 0.5756P] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.027 | (Δ/σ)max < 0.001 |
| wR(F2) = 0.076 | Δρmax = 0.25 e Å−3 |
| S = 1.02 | Δρmin = −0.21 e Å−3 |
| 2294 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 160 parameters | Extinction coefficient: 0.00076 (7) |
| 0 restraints |
| [Zn(C6H5S)2(C18H12N2)] | V = 2536.8 (4) Å3 |
| Mr = 539.99 | Z = 4 |
| Monoclinic, C2/c | Cu Kα radiation |
| a = 17.141 (2) Å | µ = 3.04 mm−1 |
| b = 11.5591 (8) Å | T = 295 K |
| c = 12.8318 (14) Å | 0.30 × 0.19 × 0.11 mm |
| β = 93.811 (10)° |
| Enraf–Nonius CAD-4 diffractometer | 1821 reflections with I > 2σ(I) |
| Absorption correction: analytical (Alcock, 1970) | Rint = 0.025 |
| Tmin = 0.531, Tmax = 0.796 | θmax = 67.5° |
| 4580 measured reflections | 3 standard reflections every 195 reflections |
| 2294 independent reflections | intensity decay: 6% |
| R[F2 > 2σ(F2)] = 0.027 | H-atom parameters constrained |
| wR(F2) = 0.076 | Δρmax = 0.25 e Å−3 |
| S = 1.02 | Δρmin = −0.21 e Å−3 |
| 2294 reflections | Absolute structure: ? |
| 160 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | ||
| Zn1 | 0.0000 | 0.23564 (3) | 0.7500 | 0.03902 (14) | |
| S1 | 0.10148 (4) | 0.31521 (5) | 0.84622 (4) | 0.05310 (18) | |
| C2 | 0.02308 (12) | −0.00711 (17) | 0.70235 (14) | 0.0373 (4) | |
| N1 | 0.03843 (10) | 0.09607 (14) | 0.66414 (12) | 0.0377 (4) | |
| C11 | 0.13310 (13) | 0.43928 (18) | 0.78028 (16) | 0.0431 (5) | |
| C8 | 0.09842 (15) | 0.2144 (2) | 0.53830 (18) | 0.0564 (6) | |
| H8 | 0.0808 | 0.2807 | 0.5703 | 0.068* | |
| C7 | 0.14180 (17) | 0.2230 (3) | 0.4526 (2) | 0.0700 (8) | |
| H7 | 0.1534 | 0.2957 | 0.4267 | 0.084* | |
| C10 | 0.10770 (12) | 0.0041 (2) | 0.52807 (16) | 0.0453 (5) | |
| C9 | 0.08090 (12) | 0.10452 (19) | 0.57723 (15) | 0.0409 (5) | |
| C3 | 0.04840 (14) | −0.10960 (19) | 0.65728 (17) | 0.0487 (5) | |
| H3 | 0.0371 | −0.1810 | 0.6861 | 0.058* | |
| C6 | 0.16875 (17) | 0.1242 (3) | 0.4038 (2) | 0.0702 (8) | |
| H6 | 0.1985 | 0.1318 | 0.3462 | 0.084* | |
| C4 | 0.09000 (14) | −0.1033 (2) | 0.57026 (17) | 0.0514 (5) | |
| H4 | 0.1066 | −0.1708 | 0.5390 | 0.062* | |
| C13 | 0.23087 (15) | 0.5875 (2) | 0.7683 (2) | 0.0638 (7) | |
| H13 | 0.2775 | 0.6210 | 0.7942 | 0.077* | |
| C15 | 0.12222 (16) | 0.5836 (2) | 0.6443 (2) | 0.0609 (7) | |
| H15 | 0.0951 | 0.6146 | 0.5856 | 0.073* | |
| C14 | 0.19151 (16) | 0.6336 (2) | 0.6820 (2) | 0.0640 (7) | |
| H14 | 0.2112 | 0.6980 | 0.6492 | 0.077* | |
| C16 | 0.09275 (15) | 0.4876 (2) | 0.69300 (18) | 0.0526 (6) | |
| H16 | 0.0457 | 0.4551 | 0.6673 | 0.063* | |
| C5 | 0.15209 (15) | 0.0177 (3) | 0.43955 (18) | 0.0589 (6) | |
| H5 | 0.1699 | −0.0474 | 0.4057 | 0.071* | |
| C12 | 0.20215 (14) | 0.4915 (2) | 0.8175 (2) | 0.0551 (6) | |
| H12 | 0.2296 | 0.4616 | 0.8764 | 0.066* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Zn1 | 0.0495 (2) | 0.0321 (2) | 0.0360 (2) | 0.000 | 0.00750 (15) | 0.000 |
| S1 | 0.0643 (4) | 0.0479 (3) | 0.0456 (3) | −0.0058 (2) | −0.0081 (3) | 0.0087 (2) |
| C2 | 0.0443 (10) | 0.0359 (10) | 0.0317 (9) | 0.0018 (8) | 0.0014 (8) | −0.0010 (8) |
| N1 | 0.0427 (9) | 0.0378 (8) | 0.0332 (8) | −0.0015 (7) | 0.0070 (7) | −0.0011 (7) |
| C11 | 0.0473 (11) | 0.0395 (11) | 0.0428 (11) | 0.0013 (9) | 0.0053 (9) | −0.0050 (9) |
| C8 | 0.0727 (15) | 0.0512 (13) | 0.0478 (12) | −0.0120 (12) | 0.0220 (11) | −0.0036 (11) |
| C7 | 0.0817 (18) | 0.0749 (18) | 0.0565 (15) | −0.0219 (15) | 0.0276 (13) | 0.0013 (14) |
| C10 | 0.0416 (11) | 0.0590 (13) | 0.0350 (10) | 0.0065 (10) | 0.0014 (8) | −0.0100 (9) |
| C9 | 0.0427 (11) | 0.0487 (11) | 0.0319 (9) | −0.0024 (9) | 0.0065 (8) | −0.0053 (8) |
| C3 | 0.0673 (14) | 0.0376 (10) | 0.0411 (11) | 0.0069 (10) | 0.0031 (10) | −0.0029 (9) |
| C6 | 0.0652 (16) | 0.100 (2) | 0.0484 (14) | −0.0113 (15) | 0.0260 (12) | −0.0077 (14) |
| C4 | 0.0640 (14) | 0.0471 (12) | 0.0430 (12) | 0.0137 (11) | 0.0027 (10) | −0.0090 (10) |
| C13 | 0.0458 (13) | 0.0585 (15) | 0.088 (2) | −0.0082 (11) | 0.0126 (13) | −0.0126 (14) |
| C15 | 0.0744 (17) | 0.0461 (12) | 0.0626 (16) | −0.0010 (12) | 0.0081 (13) | 0.0118 (12) |
| C14 | 0.0654 (16) | 0.0470 (14) | 0.0823 (18) | −0.0036 (12) | 0.0257 (14) | 0.0036 (13) |
| C16 | 0.0613 (14) | 0.0447 (12) | 0.0508 (12) | −0.0067 (10) | −0.0024 (11) | 0.0027 (10) |
| C5 | 0.0553 (14) | 0.0800 (17) | 0.0426 (12) | 0.0063 (13) | 0.0132 (10) | −0.0136 (12) |
| C12 | 0.0485 (13) | 0.0562 (14) | 0.0603 (14) | 0.0008 (11) | 0.0020 (11) | −0.0058 (12) |
| Zn1—N1i | 2.0849 (16) | C10—C9 | 1.412 (3) |
| Zn1—N1 | 2.0849 (16) | C10—C5 | 1.417 (3) |
| Zn1—S1 | 2.2607 (6) | C3—C4 | 1.366 (3) |
| Zn1—S1i | 2.2607 (6) | C3—H3 | 0.9300 |
| S1—C11 | 1.768 (2) | C6—C5 | 1.351 (4) |
| C2—N1 | 1.323 (3) | C6—H6 | 0.9300 |
| C2—C3 | 1.400 (3) | C4—H4 | 0.9300 |
| C2—C2i | 1.500 (4) | C13—C14 | 1.366 (4) |
| N1—C9 | 1.375 (2) | C13—C12 | 1.383 (4) |
| C11—C12 | 1.385 (3) | C13—H13 | 0.9300 |
| C11—C16 | 1.393 (3) | C15—C14 | 1.380 (4) |
| C8—C7 | 1.371 (3) | C15—C16 | 1.386 (3) |
| C8—C9 | 1.405 (3) | C15—H15 | 0.9300 |
| C8—H8 | 0.9300 | C14—H14 | 0.9300 |
| C7—C6 | 1.396 (4) | C16—H16 | 0.9300 |
| C7—H7 | 0.9300 | C5—H5 | 0.9300 |
| C10—C4 | 1.396 (3) | C12—H12 | 0.9300 |
| N1i—Zn1—N1 | 78.61 (9) | C4—C3—C2 | 119.0 (2) |
| N1i—Zn1—S1 | 106.55 (5) | C4—C3—H3 | 120.5 |
| N1—Zn1—S1 | 110.17 (5) | C2—C3—H3 | 120.5 |
| N1i—Zn1—S1i | 110.17 (5) | C5—C6—C7 | 120.7 (2) |
| N1—Zn1—S1i | 106.55 (5) | C5—C6—H6 | 119.7 |
| S1—Zn1—S1i | 131.98 (3) | C7—C6—H6 | 119.7 |
| C11—S1—Zn1 | 108.53 (7) | C3—C4—C10 | 120.2 (2) |
| N1—C2—C3 | 122.36 (18) | C3—C4—H4 | 119.9 |
| N1—C2—C2i | 115.52 (11) | C10—C4—H4 | 119.9 |
| C3—C2—C2i | 122.11 (12) | C14—C13—C12 | 120.8 (2) |
| C2—N1—C9 | 119.58 (17) | C14—C13—H13 | 119.6 |
| C2—N1—Zn1 | 115.11 (12) | C12—C13—H13 | 119.6 |
| C9—N1—Zn1 | 125.20 (14) | C14—C15—C16 | 120.5 (2) |
| C12—C11—C16 | 118.0 (2) | C14—C15—H15 | 119.7 |
| C12—C11—S1 | 118.08 (17) | C16—C15—H15 | 119.7 |
| C16—C11—S1 | 123.91 (17) | C13—C14—C15 | 119.2 (2) |
| C7—C8—C9 | 119.4 (2) | C13—C14—H14 | 120.4 |
| C7—C8—H8 | 120.3 | C15—C14—H14 | 120.4 |
| C9—C8—H8 | 120.3 | C15—C16—C11 | 120.5 (2) |
| C8—C7—C6 | 120.9 (3) | C15—C16—H16 | 119.8 |
| C8—C7—H7 | 119.5 | C11—C16—H16 | 119.8 |
| C6—C7—H7 | 119.5 | C6—C5—C10 | 120.6 (2) |
| C4—C10—C9 | 118.17 (19) | C6—C5—H5 | 119.7 |
| C4—C10—C5 | 123.5 (2) | C10—C5—H5 | 119.7 |
| C9—C10—C5 | 118.4 (2) | C13—C12—C11 | 120.9 (2) |
| N1—C9—C8 | 119.33 (19) | C13—C12—H12 | 119.5 |
| N1—C9—C10 | 120.6 (2) | C11—C12—H12 | 119.5 |
| C8—C9—C10 | 120.04 (19) |
| Symmetry codes: (i) −x, y, −z+3/2. |
This work was supported in part by funds provided by the University of North Carolina at Charlotte and the Davidson College Faculty Study and Research Grants. Support for REU participant TBM was provided by the National Science Foundation, award number CHE-0851797.
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Deeply colored, luminescent complexes of zinc(II) arise when this d10 ion is coordinated with mixed ligands of benzenethiol anions and dinitrogenpolypyridyl ligands (Koester, 1975; Crosby et al., 1985; Highland et al., 1986). In many cases, the lowest-lying excited state of this class of molecules has been assigned to a charge transfer from the thiol to a π* molecular orbital on the nitrogen heterocycle (Koester, 1975; Highland et al., 1986). The straightforward synthesis of the complexes, the cost, and the variety of ligand substitutions that are possible, enable numerous ways to tune the energy of this ligand-to-ligand charge transfer state. The closed-shell zinc(II) complex of this study absorbs strongly in the visible region of the spectrum and serves as a model for future complexes that will be incorporated into light-harvesting arrays.
The molecular structure of the title compound is illustrated in Fig. 1. The ligands are arranged tetrahedrally around the zinc atom, which lies on a 2-fold rotation axis. The benzenethiolate ligand and the biquinoline ligand are nearly perpendicular to one another, making a dihedral angle of 84.09 (5)°. The benzenethiolate ligands make a 72.30 (5)° angle with one another. The biquinoline ligand is nearly planar, with a maximum deviation of 0.055 (3) Å from the mean plane of the ring system.
In the crystal of the title compound the molecules pack in a manner such that the biquinoline ligands of all molecules are parallel. An exhaustive study has been made (Janiak, 2000) of structures in the Cambridge Structural Database (Allen, 2002) which show π-π interactions between quinoline ring systems. This study showed that parallel ring systems which interact are offset by an amount related to the distance between ring centroids. In the present study, the planes of the quinoline rings related by π-π interactions are ca. 3.38 Å apart. The centeroids of the pyridine ring and the benzene ring are ca. 3.68 Å apart, and the centroid-centroid line makes an angle of 23.3° with the normal to the plane of the quinoline rings. These values are in agreement with those found in the Janiak study. The π-π interactions may account for the near-planarity of the biquinoline ligand.
A search of the Cambridge Structural Database [CSD Version 5.30; Allen, 2002] yielded two chemically comparable structures: bis(Benzenethiolato)-(2,2'-bipyridine-N,N')-zinc (Anjali et al., 1999) and (1,2-Benzenedithiolato-S,S')-(2,2'-biquinolinato-N,N')-zinc(II) (Halvorsen et al., 1995).