BENZENOID-QUINOID TAUTOMERISM OF SALICYLIDENIMINES: CRYSTAL STRUCTURES OF 5-BROMO- (HL1) AND 3-NITRO-SALICYLIDENE- (2-MORPHOLINO)ETHYLIMINE (HL2)

• Published in: Journal of structural chemistry Vol. 62; no. 3; pp. 436 - 442
• Main Authors: Sergienko, V. S., Abramenko, V. L., Churakov, A. V., Surazhskaya, M. D.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2021; Springer Nature B.V
• Subjects: Aldehydes; Atomic; Atomic/Molecular Structure and Spectra; Chemistry; Chemistry and Materials Science; Crystal structure; Crystals; Hydrogen bonds; Infrared spectroscopy; Inorganic Chemistry; Molecular; Nitrogen dioxide; Optical and Plasma Physics; Physical Chemistry; Quinones; Single crystals; Solid State Physics; synthesis; single crystal X-ray diffraction analysis; benzenoid and quinoid tautomeric forms; IR spectroscopy
• ISSN: 0022-4766; 1573-8779
• DOI: 10.1134/S0022476621030100

Two azomethynes, namely, derivatives of 5-bromo- and 3-nitrosalicyl aldehydes and 2-morpholinoethylamine ( HL 1 , Z  = Br and HL 2 , Z  = NO 2 ; in HL 1,2 R = CH 2 CH 2 N(CH 2 ) 4 O) are synthesized and analyzed by IR spectroscopy and single crystal X-ray diffraction. A benzenoid (enolimine) tautomeric form (a hydrogen atom is located at an oxygen atom) occurs in HL 1 . The structure is stabilized by an intramolecular О1–Н1В…N1 hydrogen bond (О–H 0.87(4) Å, H…N 1.83(4) Å, O…N 2.586(4) Å, ОHN angle 143(4)°). The HL 2 molecule crystallizes in the quinoidal (quinone amine) tautomeric form with the intramolecular N1–Н1…O2 hydrogen bond (N–H 0.87(2) Å, H…O 1.99(2) Å, O…N 2.659(2) Å, NHO angle 134(2)°).