{[2-Methyl-2-(phen­oxy­meth­yl)propane-1,3-di­yl]bis­(­oxy)}di­benzene

Ziad Moussa; Harbi Tomah Al-Masri; Amjed Shraim; Mohammed Fettouhi

doi:10.1107/S1600536814007594

. 2014 Apr 12;70(Pt 5):o539. doi: 10.1107/S1600536814007594

{[2-Methyl-2-(phenoxymethyl)propane-1,3-diyl]bis(oxy)}dibenzene

Ziad Moussa ^a,^*, Harbi Tomah Al-Masri ^a, Amjed Shraim ^b, Mohammed Fettouhi ^c

PMCID: PMC4011283 PMID: 24860348

Abstract

The title compound, C₂₃H₂₄O₃, was obtained in a one-step (60% yield) synthesis from 1,1,1-tris(hydroxymethyl)ethane. It features a tripodal ligand capable of complexing metal centres. One of the three conformations involving the methyl group, the central C—C bond and the phenoxy substituents is antiperiplanar while the two others are synclinal [the corresponding C—C—C—O torsion angles are −174.6 (1), −53.2 (2) and −47.3 (2)°]. In the crystal, C—H⋯O interactions link the molecules into [010] chains.

Related literature

For details of the synthesis, see: Viguier et al. (2001 ▶); Alajarín et al. (2007 ▶); Beaufort et al. (2007 ▶). For a related structure, see: Laliberté et al. (2003 ▶).

Experimental

Crystal data

C₂₃H₂₄O₃
M _r = 348.42
Monoclinic,
a = 13.5755 (15) Å
b = 6.2829 (7) Å
c = 22.514 (3) Å
β = 91.033 (2)°
V = 1920.0 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 295 K
0.41 × 0.32 × 0.11 mm

Data collection

Bruker SMART APEX area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.969, T _max = 0.991
16758 measured reflections
4770 independent reflections
2614 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.124
S = 1.00
4770 reflections
236 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); 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 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536814007594/bt6973sup1.cif

e-70-0o539-sup1.cif^{(18.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814007594/bt6973Isup2.hkl

e-70-0o539-Isup2.hkl^{(233.7KB, hkl)}

Click here for additional data file.^{(7.2KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814007594/bt6973Isup3.cml

CCDC reference: 942596

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O2ⁱ	0.93	2.59	3.5081 (19)	170

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Symmetry code: (i) Inline graphic .

Acknowledgments

We gratefully acknowledge King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia for use of the X-ray diffraction facility.

supplementary crystallographic information

1. Comment

α,α,α-tris(hydroxymethyl)ethane has been widely used in the design of polypodal ligands (Viguier et al., 2001; Alajarín et al., 2007; Beaufort et al., 2007) capable of forming stable complexes with transition metals [Cu(I), Cu(II), Ni(II), Pd(II), Y(III)] and a variety of lanthanide(III) cations (La³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺). The main step in the preparation of such compounds involves nucleophilic displacement of the hydroxyl group with various nucleophiles. The hydroxyl group is initially converted to a tosylate (Beaufort et al., 2007) or a halogen (Alajarín et al., 2007) before the substitution step is carried out. The title compound provides a related tripodal ligand that can be readily synthesized in a single step and in good yield. In the course of investigating its use as a tripodal ligand in transition metal complexation reactions, we examined its structure to determine the preferred conformation, identify the principal intermolecular interactions, and extract detailed geometric information.

Initial attempts to prepare the title compound by reacting phenol or sodium phenoxide with α,α,α-tris[(4-tolylsulfonyl)methyl]ethane or α,α,α-tris(chloromethyl)ethane were unsuccessful due to the poor nucleophilic character of phenol and its alkali metal salts. However, converting α,α,α-tris(hydroxymethyl)ethane to the corresponding trifluoromethanesulfonate derivative gave a more effective substrate with a much superior leaving group ability. Thus, the latter derivative reacted with sodium phenoxide under very mild conditions to afford the title compound in 60% isolated yield.

The X-ray structure determination of the tripodal O,O,O-ligand shows the central C2-atom to be bonded to a methyl groups and three phenoxymethyl groups. The geometry around the central C-atom could be described as a slightly distorted tetrahedron because the bond angles deviate from the ideal value of 109.47°. The C(3)-C(2)-C(10) [111.04 (13)°] and C(1)-C(2)-C(17) [110.26 (13)°], and C(1)-C(2)-C(10) [111.15 (13)°] angles are wide, and the other three angles are narrow. The three phenoxymethyl arms are tilted away from the C-center due to steric interactions. One of the three conformations involving the methyl group, the central C—C bond and each one of the three phenoxy substituents is antiperiplanar while the two others are synclinal. The corresponding torsion angles are C1—C2—C3—O1: -174.6 (1)°, C1—C2—C17—O3: -53.2 (2)° and C1—C2—C10—O2: -47.3 (2)° respectively. The bond angles and bond distances are in good agreement with those reported for the only one reported analog namely 1,3-diphenoxy-2,2-bis(phenoxymethyl)propane (Laliberté et al., 2003).

The only remarkable short intermolecular contact is a C-H···O interaction.

2. Experimental

Preparation of (2-methyl-2-(phenoxymethyl)propane-1,3-diyl)bis(oxy)dibenzene

1,1,1-tris(hydroxymethyl)ethane (600 mg, 5 mmol) was dissolved in pyridine (10 ml) and cooled to 273K in an ice/water bath. The colorless solution was treated dropwise over ten minutes with trifluoromethanesulfonic anhydride (4.34 g, 2.6 ml, 15.4 mmol) to give a deep dark red homogeneous solution and stirring was continued for another 50 minutes. Simultaneously and in a separate flask, NaH (1.98 g, 60%, 50 mmol) was washed with hexanes and suspended in THF (30 ml) at 273K. Phenol (4.23 g, 45 mmol) was added in portions to the stirred suspension over 1 h. The trifluoromethanesulfonate solution was then slowly added to the sodium phenoxide solution at 273K to give a light reddish yellow color. The ice bath was removed and the mixture was subsequently stirred overnight at room temperature. The mixture was diluted with diethyl ether (50 ml) and the ether layer was washed with 5% HCl solution (3 x 20 ml), 1 N solution of NaOH (3 x 20 ml), saturated NaCl solution (3 x 20 ml), dried (Na₂SO₄) and concentrated in vacuo. ¹H NMR analysis of the crude indicated that it consisted of a 2:1 mixture of the product and corresponding disubstituted analogue. The residue was initially chromatographed (elution with 90% hexanes-ethyl acetate) to provide an unseparated mixture of the aforementioned products. Further chromatographic separation with hexanes and re-crystallization (hexanes) afforded 1.04 g (60%) of the tripodal ligand as a colorless crystalline solid: ¹H NMR (CDCl₃, 400 MHz) δ 7.30–7.20 (m, 6H, Ar—H), 6.97–6.88 (m, 9H, Ar—H), 4.09 (s, 6H, OCH₂), 1.33 (s, 3H, CH₃); ¹³C NMR (CDCl₃, 100 MHz) δ 159.1 (C), 129.4 (CH), 120.8 (CH), 114.6 (CH), 70.0 (CH₂), 40.4 (C), 17.3 (CH₃).