3′,6′-Bis(ethyl­amino)-2-[(2-hydroxy­ethyl)­amino]-2′,7′-dimethylspiro­[isoindoline-1,9′-xanthen]-3-one

Mao-Zhong Tian; Xiao-Jun Peng

doi:10.1107/S1600536808023611

. 2008 Jul 31;64(Pt 8):o1645. doi: 10.1107/S1600536808023611

3′,6′-Bis(ethylamino)-2-[(2-hydroxyethyl)amino]-2′,7′-dimethylspiro[isoindoline-1,9′-xanthen]-3-one

Mao-Zhong Tian ^a,^*, Xiao-Jun Peng ^b

PMCID: PMC2962210 PMID: 21203332

Abstract

In the title compound, C₂₈H₃₂N₄O₃, the dihedral angle between the planes of the xanthene ring system and the spirolactam ring is 85.99 (3)°. Molecules are linked by intermolecular O—H⋯O and N—H⋯O hydrogen-bonding interactions.

Related literature

For the synthesis and related structures of rhodamine dyes, see: Ko et al. (2006 ▶); Wu et al. (2007 ▶); Zhang et al. (2008 ▶). For related literature on the photophysical properties and applications of rhodamine dyes, see: Lakowicz (2006 ▶).

Experimental

Crystal data

C₂₈H₃₂N₄O₃
M _r = 472.58
Triclinic,
a = 9.3195 (18) Å
b = 9.4770 (16) Å
c = 15.384 (3) Å
α = 94.722 (18)°
β = 107.592 (13)°
γ = 98.924 (13)°
V = 1267.4 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 298 (2) K
0.30 × 0.20 × 0.15 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: none
8770 measured reflections
4305 independent reflections
3144 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.121
S = 1.06
4305 reflections
325 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker 2005 ▶); cell refinement: APEX2; data reduction: APEX2; 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 global, I. DOI: 10.1107/S1600536808023611/zl2122sup1.cif

e-64-o1645-sup1.cif^{(26KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808023611/zl2122Isup2.hkl

e-64-o1645-Isup2.hkl^{(210.9KB, 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
N3—H3A⋯O3ⁱ	0.898 (16)	2.185 (18)	3.044 (2)	160 (2)
O3—H3C⋯O1ⁱⁱ	0.82	1.98	2.770 (2)	162

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

Acknowledgments

Financial support in part by the Natural Science Foundation of China (20376010 and 20472012) and Shanxi Scholarship Council of China (200310) is gratefully acknowledged.

supplementary crystallographic information

Comment

Among many fluorescent compounds, rhodamine dyes are known to have excellent photophysical properties, (Lakowicz, 2006) and they are one of the most widely used fluorophores for labeling and sensing biomolecules (Ko et al., 2006; Wu et al., 2007). There are a few single-crystal reports about rhodamine derivatives bearing a lactam moiety (Wu et al., 2007; Zhang et al., 2008). Detailed information on their molecular and crystal structures is necessary to understand their photophysical and photochemical properties.

In agreement with other reported models, (Wu et al., 2007) the main skeleton of the title molecule is formed by the xanthene ring and the spirolactam-ring. As shown in Figure 1, the atoms of the xanthene ring and spirolactam-rings are both nearly planar and are almost perpendicular to each other. R.m.s. deviations from planarity are 0.028 (1) Å for the xanthene ring and 0.033 (0) Å for the spirolactam-ring, respectively. The dihedral angle between the planes of the xanthene ring and the spirolactam ring is 85.99 (3)°.

Analysis of the crystal packing of the title molecule (Figure 2), shows that the molecules of the title compound are connected via intermolecular N3—H3A···O3 and O3—H3C···O1 hydrogen bonds (Table 1). The oxygen atom on the spirolactam-ring acts as acceptor for an O—H···O hydrogen bond from a neighboring molecule. The oxygen atom of the hydroxyl group in turn acts as acceptor for a N—H···O hydrogen bond from again another molecule, thus forming a chain with two consecutive hydrogen bonds of the type N—H···O—H···O═C. Via these hydrogen bonds molecules are connected into double stranded chains as shown in Figure 2.

Experimental

Sodium borohydride (15.2 mg, 0.4 mmol) was slowly added to a solution of 3',6'-bis(ethylamino)-2',7'-dimethyl-2-(2-oxoethylideneamino)spiro [isoindoline-1,9'-xanthen]-3-one (132 mg, 0.3 mmol) in ethanol (20 ml). The reaction mixture was stirred for 2 h at room temperature and the solvent was totally removed under reduced pressure. The crude product was dissolved in CH₂Cl₂ (20 ml) and 3 ml of an aqueous solution of K₂CO₃ was added. The organic layer was separated and dried over MgSO₄. After filtration, the solvent was removed under reduced pressure. The residue was placed on a silica gel column (200–300 mesh). The column was eluted with a mixture (2:1, v/v) of petroleum ether /ethyl acetate, to give 131.5 mg of the title compound (93%). Crystals were grown by dissolving the compound in CH₂Cl₂ and slowly diffusing n-hexane into the solution.