trans-4-[(4-Dimethylaminophenyl)iminomethyl]-N-methylpyridiniumpara-toluenesulfonate

Abstract

In the title compound, C15H18N3+*C7H7O3S-, the phenylene and pyridyl rings are somewhat twisted with respect to each other, forming a dihedral angle of 23.49 (6) degrees. The compound contains a dipolar chromophoric cation, but crystallizes in the centrosymmetric space group P2(1)/n and is thus not expected to display quadratic non-linear optical effects.

Electron–phonon coupling and vibrational modes contributing to linear electro‐optic effect of the efficient NLO chromophore 4‐(N,N‐dimethylamino)‐N‐methyl‐4′‐toluene sulfonate (DAST) from their vibrational spectra

“…The arrangement of alternating cationic and anionic sheets can facilitate the formation of macroscopically polar structures. [41] The crystal packing diagram in DAST crystal and structure view along the (1) a-axis (2) b-axis (3) c-axis are presented in Fig. S1 (Supporting information).…”

N,N-Diethyl-N′-[(E)-4-pyridylmethylene]benzene-1,4-diamine: a combined X-ray and density functional theory study

“…These effects are not included in the DFT structure optimization. However, the calculated value of 21.8 lies within the expected range; an even larger value of 23.49 (6) has been crystallographically determined for the trans-4-[(4-dimethylaminophenyl)iminomethyl]-N-methylpyridinium cation (Coe et al, 2001). Compound (I) shows an intense absorption band in the visible region at max = 428 nm (" = 8881 l mol À1 cm À1 ) in acetonitrile.…”

“…The molecular geometry parameters are within expected ranges. As observed in trans-4-[4-(dimethylamino)phenyliminomethyl]-N-phenylpyridinium hexafluorophosphate (Coe et al, 2000) and trans-4-[4-(dimethylamino)phenyliminomethyl]-N-methylpyridinium 4-toluenesulfonate (Coe et al, 2001), the benzene ring in (I) shows partial quinone character, which reveals some groundstate charge separation. The average C2 .…”

“…Related Schiff base chromophores have also been studied (Corradin et al, 1996;Coe et al, 2002;Sliwa et al, 2005). In this context, Coe and co-workers reported the crystal structures of two salts containing the Schiff base cations trans-4-[4-(dimethylamino)phenyliminomethyl]-N-phenylpyridinium (Coe et al, 2000) and trans-4-[4-(dimethylamino)phenyliminomethyl]-N-methylpyridinium (Coe et al, 2001). The use of organic salts enables modifica-tion of the crystal packing by variation of the counter-ions.…”

“…In the latter, the dipolar cations are aligned head-to-tail forming polar cationic sheets, between which the hexafluorophosphate anions are located. It may be significant that the closely related compound trans-4-[4-(dimethylamino)phenyliminomethyl]-Nmethylpyridinium 4-toluenesulfonate crystallizes in the centrosymmetric space group P2 1 /n (Coe et al, 2001). Compound (I) crystallizes in the polar orthorhombic space group Pna2 1 with antiparallel alignment of the dipolar chromophores.…”