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The crystal structure of 4'-{4-[(2,2,5,5-tetra-methyl-N-oxyl-3-pyrrolin-3-yl)ethyn-yl]phen-yl}-2,2':6',2''-terpyridine.

Meyer A, Wiecek J, Schnakenburg G, Schiemann O - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: The pyrroline-N-oxyl group commonly seen in such nitroxyls is found in the title structure and the mean plane of the pyrroline ring subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring.Furthermore, edge-on C-H⋯π inter-actions between the phenyl-ene rings of neighbouring mol-ecules are observed along this direction.A two-dimensional C-H⋯O hydrogen-bonded network is formed within the (010) plane.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstrasse 12, 53115 Bonn, Germany.

ABSTRACT
The terpyridine group of the title compound, C31H27N4O, assumes an all-transoid conformation and is essentially planar with the dihedral angles between the mean planes of the central pyridine and the two outer rings amounting to 3.87 (5) and 1.98 (5)°. The pyrroline-N-oxyl group commonly seen in such nitroxyls is found in the title structure and the mean plane of the pyrroline ring subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring. The intra-molecular separation between the nitrogen atom of the central pyridine unit of the terpyridine group and the nitroxyl group is 14.120 (2) Å. In the crystal, the mol-ecules are arranged in layers stacked along [001]. Slipped face-to-face π-π inter-actions between the pyridine rings are observed along this direction with the shortest centroid-centroid distances amounting to 3.700 (1) and 3.781 (1) Å. Furthermore, edge-on C-H⋯π inter-actions between the phenyl-ene rings of neighbouring mol-ecules are observed along this direction. A two-dimensional C-H⋯O hydrogen-bonded network is formed within the (010) plane. The shortest O⋯O separation between neighbouring mol-ecules is 5.412 (3) Å.

No MeSH data available.


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Scheme illustrating the synthesis of (1).
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fig6: Scheme illustrating the synthesis of (1).

Mentions: The title compound (1) is formed from 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl and 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine using a Sonogashira–Hagihara cross-coupling reaction, as shown in Fig. 6 ▸. 222 mg (0.57 mmol) of 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine, 100 mg (0.61 mmol) of 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl, 20 mg (0.076 mmol) of PPh3 and 40 mg (0.035 mmol) of Pd(PPh3)4 were dissolved in 17 ml of i-Pr2NH and stirred at 313 K, yielding a yellow solution which turned orange over the course of 5 min. Additionally, an orange precipitate was formed simultaneously. After 5.5 h, 2 ml of di­methyl­formamide were added to the orange suspension. The stirring at 313 K was continued for 16 h, after which time the solvents were removed under reduced pressure. The orange residues were suspended in a mixture of di­chloro­methane and cyclo­hexane (1:2) and subsequently subjected to column chromatography using aluminum oxide as stationary phase. A mixture of di­chloro­methane and cyclo­hexane was used as eluent. The volumetric ratio of both solvents was changed stepwise during the purification (from 1:8 to 8:1). The desired product was obtained in a yellow fraction and could be isolated by removing the eluents under reduced pressure (yield 80%). The crystallization of (1) was achieved by slow evaporation of a solution of (1) in a 1:1 mixture of aceto­nitrile and di­chloro­methane. 4′-(4-Bromo­phen­yl)-2,2′:6′,2′′-terpyridine was purchased from TCI Europe. 3-Ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl was synthesized as described by Schiemann et al. (2007 ▸).


The crystal structure of 4'-{4-[(2,2,5,5-tetra-methyl-N-oxyl-3-pyrrolin-3-yl)ethyn-yl]phen-yl}-2,2':6',2''-terpyridine.

Meyer A, Wiecek J, Schnakenburg G, Schiemann O - Acta Crystallogr E Crystallogr Commun (2015)

Scheme illustrating the synthesis of (1).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4518943&req=5

fig6: Scheme illustrating the synthesis of (1).
Mentions: The title compound (1) is formed from 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl and 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine using a Sonogashira–Hagihara cross-coupling reaction, as shown in Fig. 6 ▸. 222 mg (0.57 mmol) of 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine, 100 mg (0.61 mmol) of 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl, 20 mg (0.076 mmol) of PPh3 and 40 mg (0.035 mmol) of Pd(PPh3)4 were dissolved in 17 ml of i-Pr2NH and stirred at 313 K, yielding a yellow solution which turned orange over the course of 5 min. Additionally, an orange precipitate was formed simultaneously. After 5.5 h, 2 ml of di­methyl­formamide were added to the orange suspension. The stirring at 313 K was continued for 16 h, after which time the solvents were removed under reduced pressure. The orange residues were suspended in a mixture of di­chloro­methane and cyclo­hexane (1:2) and subsequently subjected to column chromatography using aluminum oxide as stationary phase. A mixture of di­chloro­methane and cyclo­hexane was used as eluent. The volumetric ratio of both solvents was changed stepwise during the purification (from 1:8 to 8:1). The desired product was obtained in a yellow fraction and could be isolated by removing the eluents under reduced pressure (yield 80%). The crystallization of (1) was achieved by slow evaporation of a solution of (1) in a 1:1 mixture of aceto­nitrile and di­chloro­methane. 4′-(4-Bromo­phen­yl)-2,2′:6′,2′′-terpyridine was purchased from TCI Europe. 3-Ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl was synthesized as described by Schiemann et al. (2007 ▸).

Bottom Line: The pyrroline-N-oxyl group commonly seen in such nitroxyls is found in the title structure and the mean plane of the pyrroline ring subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring.Furthermore, edge-on C-H⋯π inter-actions between the phenyl-ene rings of neighbouring mol-ecules are observed along this direction.A two-dimensional C-H⋯O hydrogen-bonded network is formed within the (010) plane.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstrasse 12, 53115 Bonn, Germany.

ABSTRACT
The terpyridine group of the title compound, C31H27N4O, assumes an all-transoid conformation and is essentially planar with the dihedral angles between the mean planes of the central pyridine and the two outer rings amounting to 3.87 (5) and 1.98 (5)°. The pyrroline-N-oxyl group commonly seen in such nitroxyls is found in the title structure and the mean plane of the pyrroline ring subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring. The intra-molecular separation between the nitrogen atom of the central pyridine unit of the terpyridine group and the nitroxyl group is 14.120 (2) Å. In the crystal, the mol-ecules are arranged in layers stacked along [001]. Slipped face-to-face π-π inter-actions between the pyridine rings are observed along this direction with the shortest centroid-centroid distances amounting to 3.700 (1) and 3.781 (1) Å. Furthermore, edge-on C-H⋯π inter-actions between the phenyl-ene rings of neighbouring mol-ecules are observed along this direction. A two-dimensional C-H⋯O hydrogen-bonded network is formed within the (010) plane. The shortest O⋯O separation between neighbouring mol-ecules is 5.412 (3) Å.

No MeSH data available.


Related in: MedlinePlus