A second monoclinic polymorph of N-(diethyl­amino­thio­carbon­yl)-N′-phenyl­benzamidine

Bernd Schröder; Ligia R Gomes; Luís M N B F Santos; Paula Brandão; John Nicolson Low

doi:10.1107/S1600536811010464

. 2011 Mar 26;67(Pt 4):o962–o963. doi: 10.1107/S1600536811010464

A second monoclinic polymorph of N-(diethylaminothiocarbonyl)-N′-phenylbenzamidine

Bernd Schröder ^a, Ligia R Gomes ^b, Luís M N B F Santos ^c, Paula Brandão ^a, John Nicolson Low ^d,^*

PMCID: PMC3099880 PMID: 21754226

Abstract

The asymmetric unit of the title compound, C₁₈H₂₁N₃S, contains five molecules. The equivalent bond distances in the five molecules are in excellent agreement, the r.m.s. fit being within 0.007 Å. The five molecules are linked into a chain consisting of alternating pseudo-enantiomers by N—H⋯S hydrogen bonds supplemented by weak C—H⋯π interactions. The action of a glide plane links the asymmetric unit into an extended chain. A polymorph of the title compound with one molecule in the asymmetric unit was reported by Braun et al. [Cryst. Res. Technol. (1988), 23, 35–39].

Related literature

For the structure of the first polymorph, see: Braun et al. (1988 ▶). For graph-set analysis, see: Bernstein et al. (1995 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶). Preparative details can be found in Beyer et al. (1984 ▶).

Experimental

Crystal data

C₁₈H₂₁N₃S
M _r = 311.44
Monoclinic,
a = 21.2894 (8) Å
b = 18.8015 (7) Å
c = 27.1792 (10) Å
β = 128.584 (2)°
V = 8504.1 (5) Å³
Z = 20
Mo Kα radiation
μ = 0.19 mm⁻¹
T = 150 K
0.20 × 0.06 × 0.03 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.963, T _max = 0.994
54002 measured reflections
17402 independent reflections
9835 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.142
S = 1.01
17398 reflections
1001 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 and SMART (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and OSCAIL (McArdle et al., 2004 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811010464/om2413sup1.cif

e-67-0o962-sup1.cif^{(57KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811010464/om2413Isup2.hkl

e-67-0o962-Isup2.hkl^{(850.3KB, hkl)}

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

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

Cg2, Cg4, Cg5, Cg8 and Cg10 are the centroids of the C121–C126, C221–C226, C321–C326, C421–C426 and C521–C526 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11⋯S24	0.86	2.62	3.440 (2)	159
N21—H21⋯S34	0.86	2.60	3.407 (2)	157
N31—H31⋯S44	0.86	2.64	3.459 (2)	161
N41—H41⋯S54	0.86	2.62	3.416 (2)	155
N51—H51⋯S14ⁱ	0.86	2.62	3.431 (2)	157
C26—H26B⋯Cg2	0.99	2.91	3.594 (4)	127
C36—H36A⋯Cg4	0.99	2.86	3.575 (4)	130
C46—H46B⋯Cg6	0.99	2.84	3.549 (4)	129
C56—H56A⋯Cg8	0.99	2.89	3.566 (4)	126
C16—H16A⋯Cg10ⁱⁱ	0.99	2.86	3.552 (4)	128

Open in a new tab

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

Acknowledgments

BS acknowledges the FCT and the European Social Fund (ESF) under the third Community Support Framework (CSF) for the award of a post-doctoral research grant (SFRH/BPD/38637/2007).

supplementary crystallographic information

Comment

As part of an investigation into the thermochemical properties of benzamidines a search of the CSD, (Allen, 2002) produced the structural details of C₁₈H₂₁N₃S with the code GIDHEG which crystallized in P2₁/n with one molecule in the asymmetric unit. This structure was published by Braun et al., 1988, but data acquisition was made at room temperature and it was found to have an ethyl group with urealistic bond lengths and hydrogen atoms on the terminal methyl group were missing. It was thus decided to carry out a new structural determination at 150 K to locate this ethyl group more accurately in order to allow the comparison of the solid state structure with that obtained from gas phase ab initio calculations. The low temperature structure crystallizes in P2₁/c with cell volume of 8504.1 (5) Å³ close to five times that for GIDHEG, 1754.0 (5) Å³ and with five molecules in the asymmetric unit. The five independent molecules are shown in Figures 1 - 5.

Equivalent bond distances among the five molecules are in excellent agreement. The r.m.s. fit is within 0.007 Å (Spek, 2009). The five molecules in the asymmetric unit are linked into a chain by N—H···S hydrogen bonds, this chain is supplemented by the action of weak C—H···π interactions. Action of a glide plane links the asymmetric unit into an extended C6 chain, Bernstein et al., 1995, Figure 6.

Figures 1 - 5 show that molecules 1, 3, and 5 are alike and molecules 2 and 4 are alike. The r.m.s. fits of their orthogonal coordinates are obtained from PLATON (Spek, 2003). These pairwise r.m.s. fits are for molecules 1 and 3, 0.202 Å; for molecules 1 and 5, 0.178 Å; for molecules 3 and 5, 0.121 Å and for molecules 2 and 4, 0.142 Å. By contrast, the pairwise r.m.s. fits between molecules in sets 1,3,5 and 2,4 range from 3.808 to 3.900 Å. The only significant differences between the sets are in the conformation of the ethyl group labeled Cx51—Cx52 and in the rotational disposition of H atoms in some of the methyl groups. When molecules 2 and 4 are inverted they map onto molecules 1, 3, and 5 except for the above-mentioned ethyl group. Thus the chain is one of alternating pseudo-enantiomers.

Experimental

The synthesis of the title compound was performed as described in detail elsewhere, Beyer et al. (1984). PureN-(diethylaminothiocarbonyl)benzimide chloride (available through the reaction of equimolar amounts of bis(N^',N^'-diethyl-N-benzoylthioureato) nickel (II) and thionyl chloride in dried THF) reacts with ammonia or primary or secondary amines, in acetone. In the presence of proton trapping reagents (excess of ammonia or an equimolar amount on triethylamine) and after removing of the precipitated triethylamine hydrochloride and successive recrystallization from ethanol, the respective N-thiocarbamoylbenzamidine was yielded as pale yellow crystals.