Dibromido(di-2-pyridyl disulfide-κ²N,N′)zinc(II)

The molecular structure of the title compound, [ZnBr₂(C₁₀H₈N₂S₂)], contains a seven-membered chelate ring in which the zinc atom is coordinated by two bromide ions and by the two pyridyl N atoms of a single 2,2′-dipyridyldisulfide (dpds) ligand within a slightly distorted tetra­hedron. As is usual for this type of complex, the disulfide group does not participate in zinc coordination. The chelate complexes are connected via weak inter­molecular C—H...Br hydrogen bonding into chains, which extend in the [010] direction.

Key indicators

• Single-crystal X-ray study
• T = 170 K
• Mean [sigma](C-C) = 0.010 Å
• R factor = 0.046
• wR factor = 0.120
• Data-to-parameter ratio = 16.8

checkCIF/PLATON results

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Alert level C
CELLV02_ALERT_1_C  The supplied cell volume s.u. differs from that
            calculated from the cell parameter s.u.'s by > 2
            Calculated cell volume su =      15.67
            Cell volume su given      =      12.00
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         11

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
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S1. Comment

In our ongoing investigation on the synthesis, structures and properties of new coordination polymers based on zinc(II) halides and N-donor ligands (Bhosekar et al. 2007), we have startet systematic investigation of their thermal behavior because we have demonstrated that new ligand-deficient coordination polymers can be conveniently prepared by thermal decompisition of suitable ligand-rich precursur compounds (Näther et al. 2003; Näther & Jess, 2006). In further investigations we have reacted zinc(II) bromine with 2,2'-bipyridyldisulfide (dpds). In this reaction the title chelate-complex has been formed by accident.

The versatile coordination properties of dpds enables a series of different chelate-complexes and coordination polymers. It can act in N,N'-bidentate (Kinoshita et al., 2003; Kadooka et al. 1976 & Pickardt et al. 2005) or bridging (Kubo et al. 1998 & Kinoshita et al. 2003) coordination modes toward many metals. When dpds is connected to the metal atom as a chelate ligand, a seven-membered ring is formed.

The title compound is isotypic to that of the corresponding chloride compound reported by Pickardt et al. in 2005. In the crystal structure the coordination geometry about the Zn(II) ion is almost tetrahedral with bonds being formed to two bromine ions and the two pyridyl nitrogen atoms of a single dpds ligand (Fig. 1). These latter interactions result in the formation of a seven-membered chelate ring. As usual for this type of complexes, the disulfide group does not participate in zinc-coordination. Moreover the chelate-complexes form infinite weak C—H···Br intermolecular hydrogen bonded chains along the [0 1 0] direction (C12—H12: 0.95 Å, H12···Br2ⁱ: 2.84 (2) Å, C12···Br2ⁱ: 3.74 (3), C12—H12···Brⁱ: 160 °, see Fig. 2). The Zn—Br and Zn—N distances are in the range of 2.3664 (10)–2.3897 (10) and 2.042 (5)–2.091 (5) Å. The angles at Zn(II) range from 100.99 (15) to 119.06 (4)°, the largest being Br—Zn—Br (Tab. 1). The structural parameters in the dpds molecule are quite regular. In particular the C—S bond, 1.784 (7)–1.783 (6) Å, is in good agreement with those expected for C(sp²)—S bonds (1.77 Å). The S—S bond length, 2.050 (3) Å, is somewhat longer than that found in the structure of the free ligand, 2.016 (2) Å (Raghavan & Seff, 1977).

Related literature

For related literature, see: Bhosekar et al. (2007); Kinoshita et al. (2003); Kadooka et al. (1976); Kubo et al. (1998); Näther & Jess (2006); Näther et al. (2003); Pickardt et al. (2005); Raghavan & Seff (1977).

S2. Experimental

ZnBr₂ and dpds was obtained from Alfa Aesar and methanol was obtained from Fluka. 0.125 mmol (28.15 mg) zinc(II) bromine, 0.125 mmol (27.5 mg) dpds and 3 ml of methanol were transfered in a test-tube, which were closed and heated to 110 °C for four days. On cooling colourless block-shaped single crystals of (I) were obtained.

S3. Refinement

All H atoms were located in difference map but were positioned with idealized geometry and were refined isotropic with U_eq(H) = 1.2 U_eq(C) of the parent atom using a riding model with C—H = 0.95 Å.

Computing details

Data collection: IPDS Program Package (Stoe, 1998); cell refinement: IPDS Program Package (Stoe, 1998); data reduction: IPDS Program Package (Stoe, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1998); software used to prepare material for publication: CIFTAB SHELXTL (Bruker, 1998).

Figures

	Fig. 1. : Molecular structure of the title compund with labelling and displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. : Crystal structure of the title compound with view along the [0 1 0] direction. Intermolecular C—H···Br hydrogen bonding is shown as dashed lines. Symmetry code: i = x, -1 + y, z.

Dibromido(di-2-pyridyl disulfide-κ²N,N')zinc(II)

Crystal data

[ZnBr2(C10H8N2S2)]	Z = 2
Mr = 445.49	F(000) = 428
Triclinic, P1	Dx = 2.177 Mg m^−3
a = 7.7610 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.2962 (8) Å	Cell parameters from 8000 reflections
c = 12.3576 (13) Å	θ = 2.9–28.1°
α = 95.488 (12)°	µ = 7.97 mm^−1
β = 107.161 (12)°	T = 170 K
γ = 112.950 (11)°	Block, colourless
V = 679.70 (12) Å^3	0.09 × 0.09 × 0.08 mm

Data collection

STOE IPDS-1 diffractometer	2167 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.054
Graphite monochromator	θmax = 26.0°, θmin = 2.9°
Phi scans	h = −9→9
6076 measured reflections	k = −10→10
2609 independent reflections	l = −15→15

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.046	H-atom parameters constrained
wR(F^2) = 0.120	w = 1/[σ^2(Fo^2) + (0.0684P)^2 + 2.046P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
2609 reflections	Δρmax = 1.31 e Å^−3
155 parameters	Δρmin = −1.43 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0071 (16)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.99364 (9)	0.75728 (8)	0.23015 (6)	0.0193 (2)
Br2	0.38203 (9)	0.48414 (9)	0.12968 (6)	0.0197 (2)
Zn1	0.70460 (10)	0.50584 (9)	0.22904 (6)	0.0143 (2)
S1	0.7276 (3)	0.2365 (2)	0.44635 (15)	0.0223 (4)
N1	0.7378 (8)	0.5577 (7)	0.4048 (5)	0.0167 (11)
C2	0.7679 (9)	0.5176 (10)	0.5987 (6)	0.0222 (14)
H2	0.7685	0.4418	0.6517	0.027*
C5	0.7566 (10)	0.7263 (9)	0.4404 (5)	0.0190 (13)
H5	0.7473	0.7974	0.3850	0.023*
C1	0.7414 (9)	0.4556 (9)	0.4828 (5)	0.0166 (13)
C3	0.7933 (10)	0.6913 (10)	0.6347 (6)	0.0248 (15)
H3	0.8134	0.7373	0.7131	0.030*
C4	0.7888 (10)	0.7975 (10)	0.5545 (7)	0.0263 (15)
H4	0.8077	0.9175	0.5777	0.032*
S2	0.5117 (2)	0.1119 (2)	0.28313 (15)	0.0213 (4)
N11	0.7411 (7)	0.2888 (7)	0.1671 (5)	0.0151 (10)
C15	0.8390 (9)	0.2991 (9)	0.0928 (5)	0.0183 (13)
H15	0.9064	0.4133	0.0785	0.022*
C11	0.6512 (9)	0.1280 (8)	0.1897 (5)	0.0156 (12)
C14	0.8465 (10)	0.1511 (10)	0.0359 (6)	0.0237 (15)
H14	0.9146	0.1632	−0.0175	0.028*
C13	0.7523 (10)	−0.0148 (9)	0.0587 (6)	0.0225 (14)
H13	0.7544	−0.1189	0.0209	0.027*
C12	0.6535 (10)	−0.0270 (9)	0.1385 (6)	0.0227 (14)
H12	0.5899	−0.1386	0.1570	0.027*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0160 (3)	0.0134 (4)	0.0251 (4)	0.0025 (3)	0.0079 (3)	0.0054 (2)
Br2	0.0136 (3)	0.0182 (4)	0.0257 (4)	0.0065 (3)	0.0050 (3)	0.0070 (3)
Zn1	0.0137 (4)	0.0105 (4)	0.0198 (4)	0.0056 (3)	0.0067 (3)	0.0045 (3)
S1	0.0257 (9)	0.0218 (9)	0.0254 (9)	0.0145 (7)	0.0097 (7)	0.0113 (7)
N1	0.015 (3)	0.018 (3)	0.019 (3)	0.008 (2)	0.006 (2)	0.006 (2)
C2	0.016 (3)	0.035 (4)	0.017 (3)	0.013 (3)	0.006 (3)	0.007 (3)
C5	0.025 (3)	0.018 (3)	0.017 (3)	0.012 (3)	0.008 (3)	0.005 (3)
C1	0.011 (3)	0.021 (3)	0.021 (3)	0.009 (3)	0.005 (2)	0.007 (3)
C3	0.022 (3)	0.038 (4)	0.013 (3)	0.013 (3)	0.006 (3)	0.001 (3)
C4	0.020 (3)	0.021 (4)	0.040 (4)	0.010 (3)	0.013 (3)	0.006 (3)
S2	0.0147 (8)	0.0164 (8)	0.0303 (9)	0.0024 (6)	0.0108 (7)	0.0054 (7)
N11	0.012 (2)	0.011 (3)	0.021 (3)	0.005 (2)	0.004 (2)	0.003 (2)
C15	0.016 (3)	0.020 (3)	0.020 (3)	0.009 (3)	0.008 (3)	0.005 (3)
C11	0.009 (3)	0.014 (3)	0.021 (3)	0.005 (2)	0.001 (2)	0.006 (2)
C14	0.020 (3)	0.026 (4)	0.028 (4)	0.014 (3)	0.009 (3)	0.003 (3)
C13	0.023 (3)	0.023 (4)	0.018 (3)	0.013 (3)	0.003 (3)	−0.006 (3)
C12	0.025 (4)	0.015 (3)	0.025 (3)	0.010 (3)	0.004 (3)	0.004 (3)

Geometric parameters (Å, º)

Br1—Zn1	2.3897 (10)	C3—H3	0.9500
Br2—Zn1	2.3664 (10)	C4—H4	0.9500
Zn1—N11	2.042 (5)	S2—C11	1.783 (6)
Zn1—N1	2.091 (5)	N11—C11	1.343 (8)
S1—C1	1.784 (7)	N11—C15	1.344 (8)
S1—S2	2.050 (3)	C15—C14	1.385 (9)
N1—C1	1.344 (8)	C15—H15	0.9500
N1—C5	1.362 (8)	C11—C12	1.387 (9)
C2—C3	1.385 (10)	C14—C13	1.386 (11)
C2—C1	1.401 (9)	C14—H14	0.9500
C2—H2	0.9500	C13—C12	1.406 (10)
C5—C4	1.385 (10)	C13—H13	0.9500
C5—H5	0.9500	C12—H12	0.9500
C3—C4	1.389 (11)
N11—Zn1—N1	117.2 (2)	C5—C4—C3	119.2 (6)
N11—Zn1—Br2	112.77 (15)	C5—C4—H4	120.4
N1—Zn1—Br2	103.61 (14)	C3—C4—H4	120.4
N11—Zn1—Br1	103.35 (15)	C11—S2—S1	104.0 (2)
N1—Zn1—Br1	100.99 (15)	C11—N11—C15	118.2 (5)
Br2—Zn1—Br1	119.06 (4)	C11—N11—Zn1	121.2 (4)
C1—S1—S2	106.7 (2)	C15—N11—Zn1	120.3 (4)
C1—N1—C5	118.1 (5)	N11—C15—C14	123.2 (6)
C1—N1—Zn1	131.4 (4)	N11—C15—H15	118.4
C5—N1—Zn1	110.4 (4)	C14—C15—H15	118.4
C3—C2—C1	118.8 (6)	N11—C11—C12	122.8 (6)
C3—C2—H2	120.6	N11—C11—S2	118.3 (4)
C1—C2—H2	120.6	C12—C11—S2	118.8 (5)
N1—C5—C4	122.2 (6)	C15—C14—C13	118.5 (6)
N1—C5—H5	118.9	C15—C14—H14	120.8
C4—C5—H5	118.9	C13—C14—H14	120.8
N1—C1—C2	122.5 (6)	C14—C13—C12	119.1 (6)
N1—C1—S1	121.5 (5)	C14—C13—H13	120.5
C2—C1—S1	115.9 (5)	C12—C13—H13	120.5
C2—C3—C4	119.1 (6)	C11—C12—C13	118.3 (6)
C2—C3—H3	120.5	C11—C12—H12	120.9
C4—C3—H3	120.5	C13—C12—H12	120.9