Crystal structure and thermochromic behavior of the inclusion compounds of 4,5-diphenyl-2-(4-nitrophenyl)-1H-imidazole and of 4,5-diphenyl-2-(2-hydroxy-5-nitrophenyl)-1H-imidazole

Kaftory, Menahem; Taycher, Helena; Botoshansky, Mark

doi:10.1039/a704490i

Cited by 19 publications

(10 citation statements)

References 7 publications

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“…a specific delocalization around atom C1, and this has been observed in almost all picrate salts. An analysis of related C-O and C-C (C1-C2 or C1-C6) distances among the picrates shows that as the C-O distance increases, the C-C distance decreases (Anitha et al, 2004;Takayanagi et al, 1996;Kaftory et al, 1998;Tanaka et al, 1994;Vembu et al, 2003). Neither of the ortho-nitro groups lies in the benzene plane; while dihedral angle for O2Á Á ÁO3 is 43.9 (1) , the other nitro group has two possible orientations having dihedral angles of 36.6 (2) and 27.0 (4) .…”

Section: Commentmentioning

confidence: 99%

3-Methylanilinium picrate

et al. 2005

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In 3‐methylanilinium picrate (3‐MAP), C7H10N+·C6H2N3O7−, one of the nitro groups in the picrate ion is rotationally disordered with site occupancy factors of 0.80 and 0.20. The expected proton transfer took place between picric acid and 3‐methylaniline, and the amine group is hydrogen bonded to two of the phenolate O atoms. The ortho‐nitro groups deviate greatly from the benzene plane of the picrate ion, facilitating hydrogen‐bond formation. While the cations are stacked as columns along the [001] direction, the anions are stacked in an offset fashion.

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Section: Commentmentioning

confidence: 99%

3-Methylanilinium picrate

et al. 2005

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“…The chemistry of lophine derivatives has a long history in relation to important physicochemical phenomena such as chemiluminescence through its oxidation and photo-, piezoand thermochromic properties (Zimmerman et al, 1961;Maeda & Hayashi, 1969, 1970. Only a few imidazole analogues or nitro derivatives of lophine are known (Inouye & Sakaino, 1985, 1986Sakaino, Fujii et al, 1990;Sakaino, Shimizu et al, 1990;Kaftory et al, 1998;Bu et al, 2003). The spectral properties of lophine derivatives are of interest: the colour change is dependent on the solvation in the crystal and in different derivatives.…”

Section: Commentmentioning

confidence: 99%

Structural comparisons between methylated and unmethylated nitrophenyl lophines

Yanover

Kaftory

2009

Acta Crystallogr C

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The lophine derivative 2-(2-nitrophenyl)-4,5-diphenyl-1H-imidazole, C21H15N3O2, (I), crystallized from ethanol as a solvent-free crystal and from acetonitrile as the monosolvate, C21H15N3O2.C2H3N, (II). Crystallization of 2-(4-nitrophenyl)-4,5-diphenyl-1H-imidazole from methanol yielded the methanol monosolvate, C21H15N3O2.CH4O, (III). Three lophine derivatives of methylated imidazole, namely, 1-methyl-2-(2-nitrophenyl)-4,5-diphenyl-1H-imidazole methanol solvate, C22H17N3O2.CH4O, (IV), 1-methyl-2-(3-nitrophenyl)-4,5-diphenyl-1H-imidazole, C22H17N3O2, (V), and 1-methyl-2-(4-nitrophenyl)-4,5-diphenyl-1H-imidazole, C22H17N3O2, (VI), were recrystallized from methanol, acetonitrile and ethanol, respectively, but only (IV) produced a solvate. Compounds (III) and (IV) each crystallize with two independent molecules in the asymmetric unit. Five imidazole molecules in the six crystals differ in their molecular conformations by rotation of the aromatic rings with respect to the central imidazole ring. In the absence of a methyl group on the imidazole [compounds (I)-(III)], the rotation angles are not strongly affected by the position of the nitro group [44.8 (2) and 45.5 (1) degrees in (I) and (II), respectively, and 15.7 (2) and 31.5 (1) degrees in the two molecules of (III)]. However, the rotation angle is strongly affected by the presence of a methyl group on the imidazole [compounds (IV)-(VI)], and the position of the nitro group (ortho, meta or para) on a neighbouring benzene ring; values of the rotation angle range from 26.0 (1) [in (VI)] to 85.2 (1) degrees [in (IV)]. This group repulsion also affects the outer N-C-N bond angle. The packing of the molecules in (I), (II) and (III) is determined by hydrogen bonding. In (I) and (II), molecules form extended chains through N-H...N hydrogen bonds [with an N...N distance of 2.944 (5) A in (I) and 2.920 (3) A in (II)], while in (III) the chain is formed with a methanol solvent molecule as the mediator between two imidazole rings, with O...N distances of 2.788 (4)-2.819 (4) A. In the absence of the imidazole N-H H-atom donor, the packing of molecules (IV)-(VI) is determined by weaker intermolecular interactions. The methanol solvent molecule in (IV) is hydrogen bonded to imidazole [O...N = 2.823 (4) A] but has no effect on the packing of molecules in the unit cell.

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“…For information about the Cambridge Database, see: Allen (2002). For related literature, see: Inouye & Sakaino (2000); Kaftory et al (1998); Santos et al (2001).…”

Section: Related Literaturementioning

confidence: 99%

Lophine (2,4,5-triphenyl-1H-imidazole)

Yanover

Kaftory

2009

Acta Cryst E

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The title compound, C21H16N2, has been known since 1877. Although the crystal structure of 36 derivatives of lophine are known, the structure of parent compound has remained unknown until now. The three phenyl rings bonded to the imidazole core are not coplanar with the latter, with dihedral angles of 21.4 (3), 24.7 (3), and 39.0 (3)°, respectively, between the phenyl ring planes in the 2-, 4- and 5-positions of the imidazole ring. The molecules are packed in layers running perpendicular to the b axis. Although there are acceptor and donor atoms for hydrogen bonds, no such interactions are detected in the crystal in contrast to other lophine derivatives.

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Crystal structure and thermochromic behavior of the inclusion compounds of 4,5-diphenyl-2-(4-nitrophenyl)-1H-imidazole and of 4,5-diphenyl-2-(2-hydroxy-5-nitrophenyl)-1H-imidazole

Cited by 19 publications

References 7 publications

3-Methylanilinium picrate

3-Methylanilinium picrate

Structural comparisons between methylated and unmethylated nitrophenyl lophines

Lophine (2,4,5-triphenyl-1H-imidazole)

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