Crystal structure of 1,2-bis­(2,6-di­methyl­phen­yl)-3-phenyl­guanidine

Hongfei Han; Zhiqiang Guo; Xuehong Wei

doi:10.1107/S2056989015011822

. 2015 Jun 27;71(Pt 7):o506–o507. doi: 10.1107/S2056989015011822

Crystal structure of 1,2-bis(2,6-dimethylphenyl)-3-phenylguanidine

Hongfei Han ^a,^*, Zhiqiang Guo ^b, Xuehong Wei ^a

PMCID: PMC4518950 PMID: 26279934

Abstract

In the title compound, C₂₃H₂₅N₃, the dihedral angles between the planes of the benzene ring and the two substituent dimethylphenyl rings are 60.94 (7)° and 88.08 (7)°, and the dihedral angle between the planes of the two dimethylphenyl rings is 58.01 (7)°. In the crystal, weak C—H⋯N interactions exist between adjacent molecules. One of the dimethylphenyl rings has a small amount of π–π overlap with the phenyl ring of an adjacent molecule [centroid-to-centroid distance = 3.9631 (12) Å].

Keywords: crystal structure, guanidines, hydrogen bonding, π–π overlap

Related literature

For similar structures of various related compounds, see: Boeré et al. (2000 ▸); Brazeau et al. (2012 ▸); Ghosh et al. (2008 ▸); Han & Huynh (2009 ▸); Chlupatý & Padělková (2014 ▸); Yildirim et al. (2007 ▸); Zhang et al. (2009 ▸). For applications of guanidines, see: Berlinck (2002 ▸); Heys et al. (2000 ▸); Laeckmann et al. (2002 ▸); Kelley et al. (2001 ▸); Moroni et al. (2001 ▸). graphic file with name e-71-0o506-scheme1.jpg

Experimental

Crystal data

C₂₃H₂₅N₃
M _r = 343.46
Orthorhombic,
a = 19.003 (7) Å
b = 7.924 (3) Å
c = 13.056 (5) Å
V = 1966.0 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 194 K
0.35 × 0.33 × 0.30 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▸) T _min = 0.976, T _max = 0.980
10737 measured reflections
3547 independent reflections
2649 reflections with I > 2σ(I)
R _int = 0.038

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.104
S = 1.02
3547 reflections
239 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▸); cell refinement: SAINT (Bruker, 2007 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: SHELXTL (Sheldrick, 2008 ▸); software used to prepare material for publication: publCIF (Westrip, 2010 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015011822/pk2556sup1.cif

e-71-0o506-sup1.cif^{(26.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015011822/pk2556Isup2.hkl

e-71-0o506-Isup2.hkl^{(173.9KB, hkl)}

Click here for additional data file.^{(7.6KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015011822/pk2556Isup3.cml

Click here for additional data file.^{(1.4MB, tif)}

. DOI: 10.1107/S2056989015011822/pk2556fig1.tif

The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.

CCDC reference: 1407910

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
C4H4N2ⁱ	0.95	2.61	3.457(3)	148

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Symmetry code: (i) Inline graphic .

Acknowledgments

Financial support from the National Natural Science Foundation of China (No. 21272142), the Special Fund for Agro-Scientific Research in the Public Interest (No. 201303106), and the Patent Promotion Program of Shanxi Province (No. 141006) are gratefully acknowledged.

supplementary crystallographic information

S1. Structural commentary

Guanidines are important compounds due to their possible application in medicine, biology and chemistry (Berlinck et al., 2002; Heys et al., 2000). In particular, they have received increasing interest as medicinal agents with antitumour, anti-hypertensive, antiglaucoma and cardiotonic activities (Laeckmann et al., 2002; Kelley et al., 2001; Moroni et al., 2001). In search of guanidinato metal complexes and their catalytic behaviors, we synthesized a new substituted guanidine by insertion of phenylamine with a symmetric carbodiimine, the crystal structure of which is presented here. In addition to two examples of phenyl-substituted benzimidazol amines (Ghosh et al., 2008; Yildirim et al., 2007), the title compound is structurally similar to the known compounds, 1-cyclohexyl-2,3-diphenylguanidine (Zhang et al., 2009), 1-(2,6-diisopropylphenyl)-2,3-dimesitylguanidine (Brazeau et al., 2012), N,N',N''-tris(2,6-dimethylphenyl)guanidine (Han & Huynh, 2009), 2-[2,6-Bis(propan-2-yl)phenyl]-1,3-dicyclohexylguanidine (Chlupatý & Padělková, 2014) and N,N',N''-tris(2,6-di-isopropylphenyl)guanidine (Boere et al., 2000).

The molecular structure of the title compound is illustrated in Fig. 1. The C9—N2 bond in the guanidine unit is 1.266 (2) Å, and is characteristic for a C═N imine double bond. The bond lengths of C9—N1 and C9—N3 are 1.365 (2) and 1.376 (2) Å, showing single bond character (Allen et al., 1987). The N—C9—N angles are 124.15 (18)° (N1—C9—N2), 121.58 (17)° (N2—C9—N3) and 114.26 (17)° (N1—C9—N3), indicating a deviation of the CN₃ plane from an ideal trigonal planar geometry. The dihedral angles between the planes of the benzene ring and the two substituent dimethylphenyl rings are 60.94 (7) and 88.08 (7)°, and the dihedral angle between the planes of the two dimethylphenyl rings is 58.01 (7)°. In the crystal, in addition to van der Waals interactions, weak C—H···N and N—H···C interactions exist between adjacent molecules. One of the dimethylphenyl rings has a small amount of π···π overlap with the phenyl ring of an adjacent (1-x, 2-y, 0.5+z) molecule [centroid-to-centroid distance = 3.9631 (12) Å].

S2. Synthesis and crystallization

To a stirred solution of phenylamine (1.863 g, 20 mmol) in hexane was added N,N'-dimethylphenyl carbodiimine (5.007 g, 20 mmol), followed by the addition of the trimethylaluminum (2.5 M, 0.40 mL, 1 mmol). After stirring for 2 h, the white precipitate was collected by suction filtration and recrystallized from hexane-diethylether (1:1) solution to obtain colorless crystals of 1,2-bis(2,6-dimethylphenyl)-3-phenylguanidine (yield: 90%). Anal. Calc. for C₂₃H₂₅N₃: C, 80.43; H, 7.34; N, 12.23. Found: C, 80.32; H, 7.25; N, 12.31%. ¹H NMR (300 MHz, CDCl₃, 25 °C) δ p.p.m. 2.35 (d, 12H, CH₃), 5.06 (s, 1H, NH), 5.56 (s, 1H, NH), 6.91 (s, 2H, PhH), 7.00 (s, 2H, PhH), 7.14 (s, 4H, PhH), 7.28 (s, 1H, PhH) , 7.58 (s, 2H, PhH).

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The N—H hydrogen atoms were located in a difference Fourier map and constrained (N—H = 0.87 Å). The C-bound H-atoms were included in calculated positions and treated as riding atoms: C—H = 0.95 - 0.98 Å with U_iso (H) = 1.2 or 1.5U_eq (C_Me).