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Neutral 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide and its salt forms with inorganic anions
Author(s) -
Araujo Vinicius Oliveira,
Tirloni Bárbara,
Streit Lívia,
Schwade Vânia Denise
Publication year - 2019
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618016467
Subject(s) - chemistry , molecule , thiocyanate , tautomer , pyridinium , semicarbazide , hydrate , hydrogen bond , salt (chemistry) , infrared spectroscopy , crystallography , chloride , intermolecular force , medicinal chemistry , inorganic chemistry , stereochemistry , organic chemistry
Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide, C 19 H 16 N 4 O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C 19 H 17 N 4 O + ·Cl − ·2H 2 O, (II), the nitrate dihydrate, C 19 H 17 N 4 O + ·NO 3 − ·2H 2 O, (III), and the thiocyanate 2.5‐hydrate, C 19 H 17 N 4 O + ·SCN − ·2.5H 2 O, (IV), of 2‐[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H 2 BzPyS] + · X − · n H 2 O, with X = Cl − and n = 2 for (II), X = NO 3 − and n = 2 for (III), and X = SCN − and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter‐ions (chloride or nitrate) are involved in the formation of a two‐dimensional arrangement by the establishment of hydrogen bonds with the N—H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π–π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H 2 BzPyS] + cation is in good agreement with the experimental results.