1,15:21,35-Bis(oxydiethyl­ene)-5,8,11,18,25,28,31,38-octa­oxa-1,15,21,35-tetra­azacyclo­tetra­decane-16,20,36,40-tetra­one–benzene (1/2): a macrotricyclic tetra­lactam

Gary L N Smith; Tam Nguyen; Douglas R Powell; Richard W Taylor

doi:10.1107/S1600536809026531

. 2009 Jul 18;65(Pt 8):o1927. doi: 10.1107/S1600536809026531

1,15:21,35-Bis(oxydiethylene)-5,8,11,18,25,28,31,38-octaoxa-1,15,21,35-tetraazacyclotetradecane-16,20,36,40-tetraone–benzene (1/2): a macrotricyclic tetralactam

Gary L N Smith ^a,^*, Tam Nguyen ^b, Douglas R Powell ^b, Richard W Taylor ^b

PMCID: PMC2977422 PMID: 21583610

Abstract

The macrotricyclic title compound, C₃₆H₆₄N₄O₁₄·2C₆H₆, is located on a crystallographic center of symmetry. The molecule has four tertiary amide bridgehead atoms and consists of two unsymmetrical 20-membered diazatetraoxamacrocycles (N₂O₄ donor atom set) connected through the N atoms by two lateral oxydiethylene bridges. The bridging subunits, together with the short bridging strand (NCCOCCN) from each monocycle, define a 24-membered ring (N₄O₄ donor atom set) that forms a central cavity.

Related literature

For general background to macrotricyclic ligands as receptors for cationic, anionic and neutral guests, see: Lehn (1973 ▶, 1988 ▶); Lehn et al. (1977 ▶). For related structures, see: Wiest & Weiss (1973 ▶); Fischer et al. (1977 ▶); Pascard et al. (1982 ▶); Rebizant et al. (1984 ▶); Groth (1986 ▶); Cheetham & Harding (1991 ▶); Bencini et al. (1992 ▶); Krakowiak et al. (1995 ▶); Plenio & Diodone (1995 ▶); Smith et al. (2007 ▶). For the synthesis, see: Dietrich et al. (1973 ▶); Cheney et al. (1978 ▶).

Experimental

Crystal data

C₃₆H₆₄N₄O₁₄·2C₆H₆
M _r = 933.13
Triclinic,
a = 8.9632 (14) Å
b = 11.988 (2) Å
c = 12.806 (2) Å
α = 72.728 (5)°
β = 71.758 (5)°
γ = 68.443 (6)°
V = 1189.4 (3) Å³
Z = 1
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100 K
0.41 × 0.37 × 0.30 mm

Data collection

Bruker APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T _min = 0.954, T _max = 0.978
9363 measured reflections
4603 independent reflections
4198 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.089
S = 1.00
4603 reflections
299 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1998 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809026531/pk2175sup1.cif

e-65-o1927-sup1.cif^{(23.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809026531/pk2175Isup2.hkl

e-65-o1927-Isup2.hkl^{(225.5KB, hkl)}

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

Acknowledgments

This work was supported by the Oklahoma Center for the Advancement of Science and Technology (grant HR06–113). The authors also thank the National Science Foundation (CHE-0130835) and the University of Oklahoma for funds to acquire the diffractometer and computers used in this work.

supplementary crystallographic information

Comment

Macrotricyclic ligands are of interest as receptors for cationic, anionic and neutral guests (Lehn et al., 1977; Lehn, 1988). The title compound (I) was isolated as the 2 + 2 addition product during the synthesis of the corresponding bicyclic cryptand 3pp1.1. A related macrotricyclic tetraamine has been reported, but with the propylene groups in (I) replaced by benzene rings (Smith et al., 2007). Fig. 1 shows that (I) contains three monocyclic rings: a 24-membered ring, B (N1/O4/N7/O24A/N1A/O4A/N7A/O24) and two 20-membered rings, A (N1/O4/N7/O11/O14/O17) and C (N1A/O4A/N7A/O11A/O14A/O17A). The two 20-membered macrocyclic rings form the ends of the skewed cylinder with two oxydiethylene bridges linking the macrocylic end groups. Each of the 20-membered rings (A and C) has an elliptical shape, with non-bonding distances of 4.495 (2)Å (N1···O11), 6.639 (2)Å (O4···O14), and 7.209 (2)Å (N7···O17). The planes defined by donor atoms (N1/N7/O11/O14/O17) of rings A (and C) (average deviation = 0.1796 Å) are parallel, and form a dihedral angle of 100.7 (2)° with the plane defined by the nitrogen donor atoms in ring B. Thus, the centers of rings A and C do not overlap in the direction defined by the O4···O14 axis. The two 20-membered rings are oriented in an opposing fashion with respect to the plane defined by the N donor atoms in ring B. Similar behavior has been seen with other cylindrical tricyclic cryptands having unsymmetric end groups. (Groth, 1986; Cheetham & Harding, 1991; Plenio & Diodone, 1995). Fig. 2 shows that the nitrogen atoms in the 24-membered ring form the corners of a parallelogram defined by the following non-bonding distances and angles: 4.300 (2)Å (N1···N7); 6.901 (2)Å (N7···N1A); 74.0 (2)° (N1···N7···N1A); 106.0 (2)° (N7···N1···N7A). As a result, the 20-membered rings are also offset along the O24···O24A axis. Analogous macrotricyclic compounds also exhibit a skewed cylindrical shape (Bencini et al., 1992; Pascard et al., 1982; Rebizant et al., 1984: Smith et al., 2007).

Experimental

The 20-membered monocyclic diamine was prepared according to reported methods (Dietrich et al., 1973). The tricyclic tetralactam was obtained as the 2 + 2 cycloaddition product from the reaction of 1,7-diaza-4,11,14,17-tetraoxacycloicosane (3.56 mmole) in 150 ml toluene and 2,2'-oxydiacetyl chloride (3.54 mmole) in 150 ml toluene. These solutions were added synchronously to 800 ml of toluene containing triethylamine (7.80 mmole) over a period of 2 h under high-dilution conditions (Dietrich et al., 1973; Cheney et al., 1978). The crude tetralactam was purified by recrystallization from benzene to give (I) in 10% overall yield. ESI-MS: m/z = 799.5 (M + Na⁺). Crystals suitable for X-ray crystallography were grown by vapor diffusion of heptane into a solution of (I) in benzene.