A four-armed Schiff base: 6,6′,6′′,6′′′-tetra­meth­oxy-2,2′,2′′,2′′′-[methanetetra­yltetra­kis(methylenenitrilo­methyl­idyne)]tetra­phenol

Guang-Qi Jiang; Jie Cai; Yun-Qian Zhang; Qian-Jun Zhang

doi:10.1107/S1600536808020618

. 2008 Jul 12;64(Pt 8):o1455. doi: 10.1107/S1600536808020618

A four-armed Schiff base: 6,6′,6′′,6′′′-tetramethoxy-2,2′,2′′,2′′′-[methanetetrayltetrakis(methylenenitrilomethylidyne)]tetraphenol

Guang-Qi Jiang ^a,^*, Jie Cai ^a, Yun-Qian Zhang ^a, Qian-Jun Zhang ^a

PMCID: PMC2962085 PMID: 21203169

Abstract

In the structure of the title compound, C₃₇H₄₀N₄O₈, pentaerythrityltetramine is bonded to four o-vanillin molecules, forming a four-armed Schiff base molecule. These molecules are connected by intermolecular C—H⋯O hydrogen bonds. Intramolecular C—H⋯N and O—H⋯N hydrogen bonds are also present.

Related literature

For related literature, see: Tanaka et al. (2006 ▶); Bernardo et al. (1996 ▶); Laliberte et al. (2004 ▶).

Experimental

Crystal data

C₃₇H₄₀N₄O₈
M _r = 668.73
Triclinic,
a = 11.3464 (11) Å
b = 12.4437 (12) Å
c = 13.0523 (14) Å
α = 75.861 (7)°
β = 88.893 (7)°
γ = 78.385 (7)°
V = 1749.6 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 273 (2) K
0.18 × 0.16 × 0.15 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.984, T _max = 0.987
16510 measured reflections
6221 independent reflections
3077 reflections with I > 2σ(I)
R _int = 0.058

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.145
S = 0.94
6194 reflections
443 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT (Bruker, 2007 ▶); 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, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808020618/om2247sup1.cif

e-64-o1455-sup1.cif^{(26.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808020618/om2247Isup2.hkl

e-64-o1455-Isup2.hkl^{(297KB, 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
O2—H2⋯N1	0.82	1.87	2.592 (3)	147
O4—H4⋯N4	0.82	1.84	2.567 (2)	147
O6—H6⋯N3	0.82	1.89	2.623 (3)	148
O7—H7⋯N2	0.82	1.88	2.612 (3)	148
C27—H27B⋯N1	0.97	2.56	2.936 (3)	103
C26—H26⋯O5ⁱ	0.93	2.58	3.309 (3)	136
C28—H28C⋯O2ⁱ	0.96	2.57	3.387 (3)	143
C12—H12⋯O6ⁱⁱ	0.93	2.59	3.400 (3)	146
C32—H32⋯O3ⁱⁱⁱ	0.93	2.42	3.289 (3)	155
C36—H36B⋯O8^iv	0.97	2.55	3.399 (3)	146

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

supplementary crystallographic information

Comment

Schiff bases have been intensively investigated during the past decades, mainly because of their strong coordination capability and diverse biological activities, such as antibacterial, antitumor activities, etc. (Tanaka et al., 2006; Bernardo et al., 1996). Pentaerythrityl tetramine and its congeners act as versatile building blocks in supramolecular chemistry and have been widely employed for the synthesis of various spiro crown ethers, spiro-macrocyclic ligands etc. (Laliberte et al., 2004). However, to the best of our knowledge, few Schiff bases and their complexes derived from pentaerythrityl tetramine have been reported. Herein,we present the synthesis and crystal structure of the multidentate Schiff base ligand derived from o-vanillin and pentaerythrityl tetramine.

The molecular structure is shown in Fig.1. The atoms C9, C18, C27, and C36 form a distorted tetrahedral geometry about the central atom C37. The structure reveals four intramolecular O—H···N hydrogen bonds and one C—H···N hydrogen bond as well as five intermolecular C—H···O hydrogen bonds (Table 1). A view of the packing is given in Fig. 2. The molecules are also connected by C—H···π interactions, with C9—H9B···Cg(1) angle of 138 °, C9···Cg(1) distance of 3.595 (3) Å and C14—H14···Cg(4) angle of 157 °, C14···Cg(4) distance of 3.614 (3) Å, where Cg(1) and Cg(4) are the centroids of the phenyl ring formed by atoms C2,C3,C4,C5,C6,C7 and C29,C30,C31,C32,C33,C34 at (1 - x,-y,1 - z) and (1 + x,y,z), respectively.

Experimental

A solution of pentaerythrityl tetramine (0.13 g, 1 mmol) in ethanol (20 ml) was added dropwise while stirring to a solution of o-vanillin (0.68 g, 4 mmol) in ethanol (20 ml),the mixture was stirred for about 2 h at room temperature. The resulting solution was filtered, and after slow evaporation of the solvent for several days, crystals suitable for X-ray diffraction were obtained in a yield of 46.4%.