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Bis­(benzene­thiol­ato)(2,2′-bi­quinoline)zinc(II)

aDepartment of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA, and bDepartment of Chemistry, Davidson College, Davidson, NC 28035, USA
*Correspondence e-mail: djones@uncc.edu, dustriplin@davidson.edu

(Received 27 August 2009; accepted 9 October 2009; online 23 October 2009)

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 ππ inter­action [interplanar distance = 3.38 (1) Å] with the neighboring biquinoline ligand.

Related literature

For luminescent complexes of zinc(II), see: Koester (1975[Koester, V. J. (1975). Chem. Phys. Lett. 32, 575-580.]); Crosby et al. (1985[Crosby, G. A., Highland, R. G. & Truesdell, K. A. (1985). Coord. Chem. Rev. 64, 41-52.]); Highland et al. (1986[Highland, R. G., Brummer, J. G. & Crosby, G. A. (1986). J. Phys. Chem. 90, 1593-1598.]). For related structures, see: Halvorsen et al. (1995[Halvorsen, K., Crosby, G. A. & Wacholtz, W. F. (1995). Inorg. Chim. Acta, 228, 81-88.]); Anjali et al. (1999[Anjali, K. S., Sampanthar, J. T. & Vittal, J. J. (1999). Inorg. Chim. Acta. 295, 9-17.]). For a study of ππ inter­actions involving quinoline ring systems, see: Janiak (2000[Janiak, C. (2000). J. Chem. Soc. Dalton Trans. pp. 3885-3896.]). For details of the Cambridge Crystal Structure Database, see: Allen et al. (2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]).

[Scheme 1]

Experimental

Crystal data
  • [Zn(C6H5S)2(C18H12N2)]

  • Mr = 539.99

  • Monoclinic, C 2/c

  • a = 17.141 (2) Å

  • b = 11.5591 (8) Å

  • c = 12.8318 (14) Å

  • β = 93.811 (10)°

  • V = 2536.8 (4) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 3.04 mm−1

  • T = 295 K

  • 0.30 × 0.19 × 0.11 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: analytical (Alcock, 1970[Alcock, N. W. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, p. 271. Copenhagen: Munksgaard.]) Tmin = 0.531, Tmax = 0.796

  • 4580 measured reflections

  • 2294 independent reflections

  • 1821 reflections with I > 2σ(I)

  • Rint = 0.025

  • 3 standard reflections every 195 reflections intensity decay: 6%

Refinement
  • R[F2 > 2σ(F2)] = 0.027

  • wR(F2) = 0.076

  • S = 1.02

  • 2294 reflections

  • 160 parameters

  • H-atom parameters constrained

  • Δρmax = 0.25 e Å−3

  • Δρmin = −0.21 e Å−3

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994[Enraf-Nonius (1994). CAD-4 EXPRESS. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: DIRDIF (Beurskens et al., 1999[Beurskens, P. T., Beurskens, G., de Gelder, R., Garciia-Granda, S., Gould, R. O., Israel, R. & Smits, J. M. M. (1999). The DIRDIF99 Program System. Technical Report of the Crystallography Laboratory, University of Nijmegen, The Netherlands.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

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).

Related literature top

For luminescent complexes of zinc(II), see: Koester (1975); Crosby et al. (1985); Highland et al. (1986). For related structures, see: Halvorsen et al. (1995); Anjali et al. (1999). For a study of ππ interactions involving quinoline ring systems, see: Janiak (2000). For details of the Cambridge Crystal Structure Database, see: Allen et al. (2002).

Experimental top

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.

Refinement top

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).

Structure description top

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).

For luminescent complexes of zinc(II), see: Koester (1975); Crosby et al. (1985); Highland et al. (1986). For related structures, see: Halvorsen et al. (1995); Anjali et al. (1999). For a study of ππ interactions involving quinoline ring systems, see: Janiak (2000). For details of the Cambridge Crystal Structure Database, see: Allen et al. (2002).

Computing details top

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).

Figures top
[Figure 1] 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] Fig. 2. Crystal packing diagram of the title compound, showing the π-π interactions between the biquinoline ligands.
Bis(benzenethiolato)(2,2'-biquinoline)zinc(II) top
Crystal data top
[Zn(C6H5S)2(C18H12N2)]F(000) = 1112
Mr = 539.99Dx = 1.414 Mg m3
Monoclinic, C2/cCu Kα radiation, λ = 1.54184 Å
Hall symbol: -C 2ycCell parameters from 25 reflections
a = 17.141 (2) Åθ = 9.8–42.1°
b = 11.5591 (8) ŵ = 3.04 mm1
c = 12.8318 (14) ÅT = 295 K
β = 93.811 (10)°Prism, orange
V = 2536.8 (4) Å30.30 × 0.19 × 0.11 mm
Z = 4
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.025
Non–profiled ω/2θ scansθmax = 67.5°, θmin = 4.6°
Absorption correction: analytical
(Alcock, 1970)
h = 2020
Tmin = 0.531, Tmax = 0.796k = 130
4580 measured reflectionsl = 1515
2294 independent reflections3 standard reflections every 195 reflections
1821 reflections with I > 2σ(I) intensity decay: 6%
Refinement top
Refinement on F2H-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) = 0.076Δρmax = 0.25 e Å3
S = 1.02Δρmin = 0.21 e Å3
2294 reflectionsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
160 parametersExtinction coefficient: 0.00076 (7)
0 restraints
Crystal data top
[Zn(C6H5S)2(C18H12N2)]V = 2536.8 (4) Å3
Mr = 539.99Z = 4
Monoclinic, C2/cCu Kα radiation
a = 17.141 (2) ŵ = 3.04 mm1
b = 11.5591 (8) ÅT = 295 K
c = 12.8318 (14) Å0.30 × 0.19 × 0.11 mm
β = 93.811 (10)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
1821 reflections with I > 2σ(I)
Absorption correction: analytical
(Alcock, 1970)
Rint = 0.025
Tmin = 0.531, Tmax = 0.7963 standard reflections every 195 reflections
4580 measured reflections intensity decay: 6%
2294 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0270 restraints
wR(F2) = 0.076H-atom parameters constrained
S = 1.02Δρmax = 0.25 e Å3
2294 reflectionsΔρmin = 0.21 e Å3
160 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Zn10.00000.23564 (3)0.75000.03902 (14)
S10.10148 (4)0.31521 (5)0.84622 (4)0.05310 (18)
C20.02308 (12)0.00711 (17)0.70235 (14)0.0373 (4)
N10.03843 (10)0.09607 (14)0.66414 (12)0.0377 (4)
C110.13310 (13)0.43928 (18)0.78028 (16)0.0431 (5)
C80.09842 (15)0.2144 (2)0.53830 (18)0.0564 (6)
H80.08080.28070.57030.068*
C70.14180 (17)0.2230 (3)0.4526 (2)0.0700 (8)
H70.15340.29570.42670.084*
C100.10770 (12)0.0041 (2)0.52807 (16)0.0453 (5)
C90.08090 (12)0.10452 (19)0.57723 (15)0.0409 (5)
C30.04840 (14)0.10960 (19)0.65728 (17)0.0487 (5)
H30.03710.18100.68610.058*
C60.16875 (17)0.1242 (3)0.4038 (2)0.0702 (8)
H60.19850.13180.34620.084*
C40.09000 (14)0.1033 (2)0.57026 (17)0.0514 (5)
H40.10660.17080.53900.062*
C130.23087 (15)0.5875 (2)0.7683 (2)0.0638 (7)
H130.27750.62100.79420.077*
C150.12222 (16)0.5836 (2)0.6443 (2)0.0609 (7)
H150.09510.61460.58560.073*
C140.19151 (16)0.6336 (2)0.6820 (2)0.0640 (7)
H140.21120.69800.64920.077*
C160.09275 (15)0.4876 (2)0.69300 (18)0.0526 (6)
H160.04570.45510.66730.063*
C50.15209 (15)0.0177 (3)0.43955 (18)0.0589 (6)
H50.16990.04740.40570.071*
C120.20215 (14)0.4915 (2)0.8175 (2)0.0551 (6)
H120.22960.46160.87640.066*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.0495 (2)0.0321 (2)0.0360 (2)0.0000.00750 (15)0.000
S10.0643 (4)0.0479 (3)0.0456 (3)0.0058 (2)0.0081 (3)0.0087 (2)
C20.0443 (10)0.0359 (10)0.0317 (9)0.0018 (8)0.0014 (8)0.0010 (8)
N10.0427 (9)0.0378 (8)0.0332 (8)0.0015 (7)0.0070 (7)0.0011 (7)
C110.0473 (11)0.0395 (11)0.0428 (11)0.0013 (9)0.0053 (9)0.0050 (9)
C80.0727 (15)0.0512 (13)0.0478 (12)0.0120 (12)0.0220 (11)0.0036 (11)
C70.0817 (18)0.0749 (18)0.0565 (15)0.0219 (15)0.0276 (13)0.0013 (14)
C100.0416 (11)0.0590 (13)0.0350 (10)0.0065 (10)0.0014 (8)0.0100 (9)
C90.0427 (11)0.0487 (11)0.0319 (9)0.0024 (9)0.0065 (8)0.0053 (8)
C30.0673 (14)0.0376 (10)0.0411 (11)0.0069 (10)0.0031 (10)0.0029 (9)
C60.0652 (16)0.100 (2)0.0484 (14)0.0113 (15)0.0260 (12)0.0077 (14)
C40.0640 (14)0.0471 (12)0.0430 (12)0.0137 (11)0.0027 (10)0.0090 (10)
C130.0458 (13)0.0585 (15)0.088 (2)0.0082 (11)0.0126 (13)0.0126 (14)
C150.0744 (17)0.0461 (12)0.0626 (16)0.0010 (12)0.0081 (13)0.0118 (12)
C140.0654 (16)0.0470 (14)0.0823 (18)0.0036 (12)0.0257 (14)0.0036 (13)
C160.0613 (14)0.0447 (12)0.0508 (12)0.0067 (10)0.0024 (11)0.0027 (10)
C50.0553 (14)0.0800 (17)0.0426 (12)0.0063 (13)0.0132 (10)0.0136 (12)
C120.0485 (13)0.0562 (14)0.0603 (14)0.0008 (11)0.0020 (11)0.0058 (12)
Geometric parameters (Å, º) top
Zn1—N1i2.0849 (16)C10—C91.412 (3)
Zn1—N12.0849 (16)C10—C51.417 (3)
Zn1—S12.2607 (6)C3—C41.366 (3)
Zn1—S1i2.2607 (6)C3—H30.9300
S1—C111.768 (2)C6—C51.351 (4)
C2—N11.323 (3)C6—H60.9300
C2—C31.400 (3)C4—H40.9300
C2—C2i1.500 (4)C13—C141.366 (4)
N1—C91.375 (2)C13—C121.383 (4)
C11—C121.385 (3)C13—H130.9300
C11—C161.393 (3)C15—C141.380 (4)
C8—C71.371 (3)C15—C161.386 (3)
C8—C91.405 (3)C15—H150.9300
C8—H80.9300C14—H140.9300
C7—C61.396 (4)C16—H160.9300
C7—H70.9300C5—H50.9300
C10—C41.396 (3)C12—H120.9300
N1i—Zn1—N178.61 (9)C4—C3—C2119.0 (2)
N1i—Zn1—S1106.55 (5)C4—C3—H3120.5
N1—Zn1—S1110.17 (5)C2—C3—H3120.5
N1i—Zn1—S1i110.17 (5)C5—C6—C7120.7 (2)
N1—Zn1—S1i106.55 (5)C5—C6—H6119.7
S1—Zn1—S1i131.98 (3)C7—C6—H6119.7
C11—S1—Zn1108.53 (7)C3—C4—C10120.2 (2)
N1—C2—C3122.36 (18)C3—C4—H4119.9
N1—C2—C2i115.52 (11)C10—C4—H4119.9
C3—C2—C2i122.11 (12)C14—C13—C12120.8 (2)
C2—N1—C9119.58 (17)C14—C13—H13119.6
C2—N1—Zn1115.11 (12)C12—C13—H13119.6
C9—N1—Zn1125.20 (14)C14—C15—C16120.5 (2)
C12—C11—C16118.0 (2)C14—C15—H15119.7
C12—C11—S1118.08 (17)C16—C15—H15119.7
C16—C11—S1123.91 (17)C13—C14—C15119.2 (2)
C7—C8—C9119.4 (2)C13—C14—H14120.4
C7—C8—H8120.3C15—C14—H14120.4
C9—C8—H8120.3C15—C16—C11120.5 (2)
C8—C7—C6120.9 (3)C15—C16—H16119.8
C8—C7—H7119.5C11—C16—H16119.8
C6—C7—H7119.5C6—C5—C10120.6 (2)
C4—C10—C9118.17 (19)C6—C5—H5119.7
C4—C10—C5123.5 (2)C10—C5—H5119.7
C9—C10—C5118.4 (2)C13—C12—C11120.9 (2)
N1—C9—C8119.33 (19)C13—C12—H12119.5
N1—C9—C10120.6 (2)C11—C12—H12119.5
C8—C9—C10120.04 (19)
Symmetry code: (i) x, y, z+3/2.

Experimental details

Crystal data
Chemical formula[Zn(C6H5S)2(C18H12N2)]
Mr539.99
Crystal system, space groupMonoclinic, C2/c
Temperature (K)295
a, b, c (Å)17.141 (2), 11.5591 (8), 12.8318 (14)
β (°) 93.811 (10)
V3)2536.8 (4)
Z4
Radiation typeCu Kα
µ (mm1)3.04
Crystal size (mm)0.30 × 0.19 × 0.11
Data collection
DiffractometerEnraf–Nonius CAD-4
Absorption correctionAnalytical
(Alcock, 1970)
Tmin, Tmax0.531, 0.796
No. of measured, independent and
observed [I > 2σ(I)] reflections
4580, 2294, 1821
Rint0.025
(sin θ/λ)max1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.027, 0.076, 1.02
No. of reflections2294
No. of parameters160
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.25, 0.21

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), DIRDIF (Beurskens et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006), WinGX (Farrugia, 1999).

 

Acknowledgements

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.

References

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