Poly[tris{μ2-4-[4-(di­methyl­amino)­phenyl­diazenyl]benzene­sulfonato}tri­dioxane­tri­sodium(I)]

Kazuyuki Sato; Hiroki Shibata; Jin Mizuguchi

doi:10.1107/S1600536808008015

. 2008 Mar 29;64(Pt 4):m586–m587. doi: 10.1107/S1600536808008015

Poly[tris{μ₂-4-[4-(dimethylamino)phenyldiazenyl]benzenesulfonato}tridioxanetrisodium(I)]

Kazuyuki Sato ^a, Hiroki Shibata ^a, Jin Mizuguchi ^a,^*

PMCID: PMC2961004 PMID: 21202034

Abstract

The title compound, [Na₃(C₁₄H₁₄N₃O₃S)₃(C₄H₈O₂)₃]_n, is a polynuclear complex which includes, in the monomeric unit, three units of Na^I-4′-dimethylaminoazobenzene-4-sulfonate [known as methyl orange (MO)] and three molecules of dioxane (C₄H₈O₂). These constitute three kinds of Na^I centres, two of which are seven-coordinate while the third is five-coordinate. One of the seven-coordinate centres is coordinated by six O atoms from the sulfonate groups of four different MOs and by one O atom from dioxane. The other is coordinated by seven O atoms from the sulfonate groups of five different MOs. The five-coordinate centre is coordinated by three O atoms from the sulfonate groups of three different MOs and two O atoms from two different dioxanes. In the crystal structure, a one-dimensional polymer chain is formed along the a axis and this ensures the thermal stability of the title compound. It is also to be noted that the N=N bond lengths of the three azo groups are appreciably different [1.259 (4), 1.196 (4), and 1.253 (4) Å].

Related literature

For general background on azo pigments, see: Herbst & Hunger (2004 ▶). For solvated methyl orange, see: Hanson (1973 ▶); Kennedy et al. (2004 ▶). For 4′-dimethylaminoazobenzene-4-sulfonic acid, see: Burke et al. (2004 ▶).

Experimental

Crystal data

[Na₃(C₁₄H₁₄N₃O₃S)₃(C₄H₈O₂)₃]
M _r = 1246.34
Orthorhombic,
a = 8.4471 (6) Å
b = 15.5153 (10) Å
c = 44.488 (3) Å
V = 5830.6 (7) Å³
Z = 4
Cu Kα radiation
μ = 2.01 mm⁻¹
T = 93 (1) K
0.45 × 0.08 × 0.07 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (Higashi, 1995 ▶) T _min = 0.468, T _max = 0.869
47815 measured reflections
10385 independent reflections
6459 reflections with F ² > 2σ(F ²)
R _int = 0.088

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.085
S = 0.81
10385 reflections
764 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.43 e Å⁻³
Absolute structure: Flack (1983 ▶), with 4457 Friedel pairs
Flack parameter: 0.006 (14)

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC & Rigaku, 2006 ▶); program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808008015/is2280sup1.cif

e-64-0m586-sup1.cif^{(57.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808008015/is2280Isup2.hkl

e-64-0m586-Isup2.hkl^{(507.8KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Na1—O1	2.341 (2)
Na1—O4	2.394 (2)
Na1—O9ⁱ	2.258 (2)
Na1—O10	2.400 (2)
Na1—O12	2.280 (2)
Na2—O2	2.288 (2)
Na2—O5	2.371 (2)
Na2—O6ⁱⁱ	2.426 (2)
Na2—O7	2.459 (2)
Na2—O7ⁱ	2.643 (2)
Na2—O8	2.570 (2)
Na2—O9ⁱ	2.477 (2)
Na3—O2ⁱ	2.402 (2)
Na3—O3ⁱ	2.604 (2)
Na3—O4ⁱⁱ	2.446 (2)
Na3—O6ⁱⁱ	2.607 (2)
Na3—O7ⁱ	2.471 (2)
Na3—O8	2.449 (2)
Na3—O14	2.434 (2)

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

supplementary crystallographic information

Comment

We are involved in the color generation mechanism of azo pigments typically characterized by the chromophore of the azo group (–N=N–). However, some types of azo pigments are also known to possess the hydrazone structure (=N—NH–), often leading to the formation of intramolecular hydrogen bonds (Herbst & Hunger, 2004). Methyl orange (MO) (NaO₃SC₆H₄N=NC₆H₄NMe₂), the skeleton of the title compound, is known as one of the classical azo pigments and its structure which includes solvent molecules as ligands have been determined by Hanson (1973) and Kennedy et al. (2004). These papers report the N/N distance to be about 1.24 Å, i.e. the typical distance of the –N=N– bond. On the other hand, the methyl orange derivative (HO₃SC₆H₄N=NC₆H₄NMe₂: 4'-dimethylaminoazobenzene-4-sulfonic acid) in which the Na atom is replace by H atom has been found to possess a zwitterionic structure in the solid state: ^-O₃SC₆H₄NH⁺=NC₆H₄NMe as characterized by a NH···O intermolecular hydrogen bond between the NH group of one molecule and one of the sulfate oxygen atoms (Burke et al., 2004). This structure reveals a lengthening of the N=N bond to 1.307 (3) Å, indicating a hydrozone-like structure. In addition, the color of the crystal is no more orange but red violet. This motivated us to study the correlation between the crystal structure and the color in these two compounds. In the course of this study, a new MO complex has been found and its structure has been determined in the present investigation.

Figure 1 shows the ORTEPIII plot (Burnett & Johnson, 1996) of the monomeric unit of (I). The asymmetric unit includes three MO molecules together with three dioxane ones. These constitute three kinds of Na(I)-complexes, two of which are seven-coordinate and the other is five-coordinate. As shown in Fig. 2, there are two kinds of seven-coordinate complexes, one of which is chelated by six O atoms from the sulfonic group of four different MOs and also by one O atom from dioxane. The other is coordinated by seven O atoms from the sulfonic group of five different MOs. The five-coordinate complex includes three O atoms from the sulfonic group of three different MOs as well as two O atoms from the two different dioxanes. It is also important to note that the N/N bond lengths are typical of the azo group (–N=N–) but these are significantly different: 1.259 (4) Å for N1/N2, 1.196 (5) Å for N4/N5, and 1.253 (4) Å for N7/N8. The monomeric unit is extended alternately to form a one dimensional polymer along the a axis as shown in Fig. 3.

Experimental

MO was purchased from Junsei Chemical Co., Ltd. Single crystals of (I) were grown by recrystallization from a dimethylacetamide solution by slow diffusion of 1,4-dioxane. After a week, a number of orange needle-like single crystals were obtained.