1,3-Bis[4-(dimethyl­amino)benz­yl]-4,5,6,7-tetra­hydro-1H-1,3-diazepan-2-ium chloride

Hakan Arslan; Don VanDerveer; Yetkin Gök; İsmail Özdemir; Bekir Çetinkaya

doi:10.1107/S1600536808041603

. 2008 Dec 13;65(Pt 1):o109–o110. doi: 10.1107/S1600536808041603

1,3-Bis[4-(dimethylamino)benzyl]-4,5,6,7-tetrahydro-1H-1,3-diazepan-2-ium chloride

Hakan Arslan ^a,^b,^*, Don VanDerveer ^c, Yetkin Gök ^d, İsmail Özdemir ^d, Bekir Çetinkaya ^e

PMCID: PMC2968033 PMID: 21581572

Abstract

The title N-heterocyclic carbene derivative, C₂₃H₃₃N₄ ⁺·Cl⁻, has been synthesized and characterized by elemental analysis, ¹H and ¹³C NMR, IR spectroscopy and a single-crystal X-ray diffraction study. Ions of the title compound are linked by three C—H⋯Cl interactions. The seven-membered 1,3-diazepane ring has a form intermediate between twist-chair and twist-boat.

Related literature

For the synthesis, see: Özdemir et al. (2005 ▶); Yaşar et al. (2008 ▶). For general background, see: Hermann (2002 ▶); Littke & Fu (2002 ▶); Evans & Boeyens (1989 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For related compounds, see: Arslan et al. (2007a ▶,b ▶,c ▶). For general background to the use of N-heterocyclic carbenes as phosphine mimics and in catalysis, see: Arduengo & Krafczyk (1998 ▶); Dullius et al. (1998 ▶); Glorius (2007 ▶); Hermann & Köcher (1997 ▶); Nolan (2006 ▶); Regitz (1996 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₂₃H₃₃N₄ ⁺·Cl⁻
M _r = 400.98
Orthorhombic,
a = 22.663 (5) Å
b = 10.081 (2) Å
c = 9.6368 (19) Å
V = 2201.7 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.19 mm⁻¹
T = 153 (2) K
0.46 × 0.12 × 0.07 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T _min = 0.918, T _max = 0.987
14704 measured reflections
1947 independent reflections
1481 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.160
S = 1.10
1947 reflections
130 parameters
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2001 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808041603/hg2445sup1.cif

e-65-0o109-sup1.cif^{(17.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808041603/hg2445Isup2.hkl

e-65-0o109-Isup2.hkl^{(95.9KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯Cl1ⁱ	0.96	2.53	3.486 (4)	180
C2—H2A⋯Cl1ⁱⁱ	0.96	2.82	3.688 (3)	151
C4—H4A⋯Cl1ⁱⁱ	0.96	2.81	3.682 (3)	152

Open in a new tab

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

Acknowledgments

We thank the Technological and Scientific Research Council of Turkey TÜBİTAK-CNRS [TBAG-U/181 (106 T716)] and İnonu University research fund (BAP 2008/03 Güdümlü) for financial support.

supplementary crystallographic information

Comment

N-heterocyclic carbenes, which can be considered phosphine mimics, have attracted considerable attentionas possible alternatives for widely used phosphine ligands (Regitz, 1996; Hermann & Köcher, 1997; Arduengo & Krafczyk, 1998; Dullius et al., 1998; Evans & Boeyens, 1989; Hermann, 2002; Littke & Fu, 2002). N-heterocyclic carbene-containing metal complexes have also revealed excellent catalytic properties in a wide range of metal-catalyzed transformations (Glorius, 2007; Nolan, 2006). Catalysts containing these ligands are useful in Heck, Suzuki and Sonogashira couplings, Buchwald Hartwig amination, olefin metathesis, hydroformylation and hydrogenation.

In recent years, we have pursued investigations on the synthesis, characterization, crystal structure, and catalytic activities of new N-heterocyclic carbene derivatives (Yaşar et al., 2008; Arslan et al., 2007a, 2007b, 2007c). In the present work, we report the preparation and characterization of a novel N-heterocyclic carbene derivative, 1,3-bis(4-(dimethylamino)benzyl)-4,5,6,7-tetrahydro-1H-1,3-diazepin-2-ium chloride, (I). The ligand was purified by re-crystallization from an ethanol:diethylether mixture (1:2) and was characterized by elemental analysis and ¹H and ¹³C-NMR spectroscopy. The analytical and spectroscopic data are consistent with the proposed structure given in Scheme 1.

The molecular structure of the title compound, (I), is depicted in Fig. 1. The structure consists of a 1,3-bis(4-(dimethylamino)benzyl)-4,5,6,7-tetrahydro-1H-1,3-diazepin-2-ium cation and a Cl^-anion. All bond lengths are in normal ranges (Allen et al., 1987). A seven-membered ring should have the chair, the boat, the twist chair or the twist boat according to Cremer & Pople (1975). The conformation of a seven-membered ring can be numerically described by four ring puckering parameters, q₂, q₃, φ₂ and φ₃. The 1,3-diazepane ring exhibits a puckered conformation, with puckering parameters Cremer & Pople (1975), q₂= 0.374 (3) Å, q₃ = 0.462 (3) Å, φ₂= 347.1 (4) °, φ₃= 115.7 (3)°, and Q_T= 0.595 (3) Å. The largest deviations from the mean plane are 0.403 (3) Å for atoms C3 and C3A. q₂should be 0 for a 100% twist chair form. According to Cremer & Pople ring-puckering analysis results, the 1,3-diazepane seven-membered ring can be accurately described as an intermediate form between the 44% twist chair form and the 55% twist boat form.

The crystal packing is shown in Fig. 2. Although there are no intramolecular D—H···A contacts, intermolecular C—H···Cl hydrogen bonds link the molecules of (I) into one-dimensional chains extending along the [010] direction (Fig. 3, Table 1) (Macrae et al., 2006).

Experimental

To a solution of 1,4-bis(p-dimethylaminobenzylamino)butane (1 mmol) CH(OEt)₃ (30 ml), NH₄Cl (1 mmol) was added; the reaction mixture was heated for 18 h at 100 °C (Scheme 2). A white solid was precipitated. Then, the precipitate was crystallized from EtOH-Et₂O (1:2) mixture (Özdemir et al., 2005). 1,3-bis(4-(dimethylamino)benzyl)-4,5,6,7-tetrahydro-1H-1,3-diazepin-2-ium chloride: Yield: 3.11 g (92%), M.p. 247–248 °C. ¹H NMR (300.13 MHz, DMSO) δ = 1.68 (quintet, J = 6.8 Hz, 4H, NCH₂CH₂CH₂CH₂N), 2.89 (s, 12H, p-(CH₃)₂NC₆H₄CH₂), 3.52 (t, J = 6.8 Hz, 4H, NCH₂CH₂CH₂CH₂N), 4.54 (s, 4H, p-(CH₃)₂NC₆H₄CH₂), 6.73 and 7.27 (d, J =8.4 Hz, 8H, p-(CH₃)₂NC₆H₄CH₂), 8.87 (s,1H, 2-CH). ¹³C{¹H}NMR (75.47 MHz, DMSO): δ = 24.7, 48.7 (NCH₂CH₂CH₂CH₂N), 40.7 (p-(CH₃)₂NC₆H₄CH₂), 60.1 (p-(CH₃)₂NC₆H₄CH₂), 112.9, 122.2, 130.1, 151.1 (p-(CH₃)₂NC₆H₄CH₂), 158.3 (2-CH). Anal. Calcd. for C₂₃H₃₃N₄Cl: C, 68.89; H, 8.29; N, 13.97. Found: C, 68.88; H, 8.30; N, 13.94.