1,3-Bis(2-meth­oxy­phen­yl)thio­urea

Jason van Rooyen; Richard Betz; Bernardus J A M van Brecht

doi:10.1107/S1600536811040852

. 2011 Oct 8;67(Pt 11):o2889. doi: 10.1107/S1600536811040852

1,3-Bis(2-methoxyphenyl)thiourea

Jason van Rooyen ^a, Richard Betz ^a,^*, Bernardus J A M van Brecht ^a

PMCID: PMC3247619 PMID: 22219924

Abstract

In the title compound, C₁₅H₁₆N₂O₂S, the N–C(=S) bond lengths are indicative of the presence of amide-type resonance. The dihedral angles between the thiourea unit and the attached aromatic rings are 59.80 (5) and 73.41 (4)° while the dihedral angle between the rings is 56.83 (4)°. In the crystal, inversion dimers linked by pairs of N—H⋯S hydrogen bonds occur. An N—H⋯π interaction is observed for the second amino group. The shortest centroid–centroid distance between two aromatic systems is 4.0958 (8) Å.

Related literature

For related structures, see: Shashidhar et al. (2006 ▶); Muhammed et al. (2007 ▶); Kuan & Tiekink (2007 ▶); Srivastava et al. (2010 ▶). For further synthetic details, see: Voss & Walter (1968 ▶). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶). For general information about coordination chemistry, see: Gade (1998 ▶). Structures containing similar bond lengths were retrieved from the Cambridge Structural Database (Allen, 2002 ▶).

Experimental

Crystal data

C₁₅H₁₆N₂O₂S
M _r = 288.36
Monoclinic,
a = 14.3187 (8) Å
b = 12.8628 (7) Å
c = 16.1168 (10) Å
β = 103.790 (3)°
V = 2882.8 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 173 K
0.42 × 0.36 × 0.14 mm

Data collection

Bruker SMART CCD diffractometer
10474 measured reflections
3567 independent reflections
2765 reflections with I > 2σ(I)
R _int = 0.058

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.090
S = 1.05
3567 reflections
191 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1998 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811040852/hb6427sup1.cif

e-67-o2889-sup1.cif^{(17.1KB, cif)}

Supplementary material file. DOI: 10.1107/S1600536811040852/hb6427Isup2.cdx

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811040852/hb6427Isup3.hkl

e-67-o2889-Isup3.hkl^{(175KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811040852/hb6427Isup4.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 is the centroid of the C11–C16 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H72⋯S1ⁱ	0.831 (16)	2.506 (17)	3.3343 (12)	174.3 (14)
N1—H71⋯Cg1ⁱⁱ	0.782 (16)	2.967 (18)	3.5127 (13)	129.1 (14)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank Dr Marc van der Vyver for helpful discussions.

supplementary crystallographic information

Comment

Chelate ligands have found widespread use in coordination chemistry due to the enhanced thermodynamic stability of resultant coordination compounds in relation to coordination compounds exclusively applying comparable monodentate ligands (Gade, 1998). Combining different donor atoms, a molecular set-up to accomodate a large variety of metal centers of variable Lewis acidity is at hand. In this aspect, the title compound, 1,3-bis(2-methoxyphenyl)thiourea, (I), seemed of interest due to its possible use as a strictly neutral or, depending on the pH value, as an anionic or cationic ligand. In addition, due to the set-up of its functional groups, it may act as mono- or multidentate ligand offering the possibility to create chelate rings of various size. The intriguing combination of a secondary amino group, a thioketo group as well as methylether groups classifies the title compound as a highly versatile ligand. To enable comparative studies in terms of bond lengths and angles in envisioned coordination compounds, we determined the molecular and crystal structure of the title compound. Information about the crystal structure of 1,3-bis(4-methoxyphenyl)thiourea (Shashidhar et al., 2006), 1,3-bis(2-methylphenyl)thiourea, (Muhammed et al., 2007; Kuan & Tiekink, 2007) and 1,3-bis(phenyl)thiourea (Srivastava et al., 2010) is available in the literature.

N–C=S bond lengths (d_N–C: 1.3469 (15) Å and 1.3488 (16) Å, respectively) are in good agreement with values deposited for comparable compounds with the Cambridge Structural Database (Allen, 2002) and are indicative of admide-type resonance between the atoms of this entity. This finding is further corroborated by the planarity of the S=CN₂ moiety (r.m.s. of all fitted atoms = 0.0015 Å). The aromatic substituents on the nitrogen atom adopt syn and anti conformation with respect to the sulfur atom. The least-squares planes defined by the carbon atoms of the respective phenyl rings enclose an angle of 56.83 (4) ° while the individual planes defined by the phenyl rings intersect with the least-squares plane defined by the atoms of the central S=CN₂ moiety at angles of 59.80 (5) ° and 73.41 (4) ° (Fig. 1, Fig. 2).

In the crystal, the hydrogen atoms of the secondary amine groups participate in two different types of intermolecular interactions. While one of the protons is part of a classical hydrogen bond of the N–H···S type, the other amine group's hydrogen atom forms a contact to one of the aromatic systems. The classical hydrogen bonds connect the molecules to centrosymmetric dimers orientated approximately perpendicular to the crystallographic b axis. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the classical hydrogen bonds is R²₂(8) on the unitary level. The shortest intercentroid distance between two aromatic systems was measured at 4.0958 (8) Å (Fig. 3).

The packing of the title compound in the crystal structure is shown in Figure 4.

Experimental

The title compound was prepared upon reacting Lawesson's reagent with the corresponding amide in analogy to a published procedure (Voss & Walter, 1968).