Structural study of three heteroaryl oximes, heteroaryl-N=OH: Compounds forming strong C3 molecular chains

Abstract

In order to further investigate the structural chemistry of oximes and to further establish the main structural arrangements adopted, we have determined the crystal structure of and carried out Hirshfeld surface calculations on three heteroaryl oximes, namely (Z)-thiophene-2-carbaldehyde oxime (1), (Z)-1H-pyrrole-2 carbaldehyde oxime (2) and (Z)-5-nitrofuran-2-carbaldehyde oxime (3). As confirmed by both techniques, the major intermolecular interactions in each compound are classical N—H···O hydrogen bonds, which link the molecules into C3 chains. Such an arrangement has been previous reported as an important aggregation mode for oximes. Secondary interactions, C—H···π and C—H···O interactions, in compounds 1 and 2, and interactions involving the nitro group oxygen atoms in compound 3 link the chains into three dimensional arrays.

Different substituent effects on the supramolecular arrays in some (E)-halo- and nitro-benzaldehyde oximes: confirmation of attractive π(C=N)···π(phenyl) interactions

“…The remaining percentage is taken up mainly by compounds in which the oxime group preferentially interacts with an acceptor substituent in the aryl unit, for example as found in pyridinyl compounds [20]. However for other heteroaromatic aldoximes (furanyl, thienyl and pyrrolyl derivatives), as we recently reported, C(3) chains are formed [21].…”

Crystal structures and Hirshfeld surfaces of four methoxybenzaldehyde oxime derivatives, 2-MeO-XC6H3C=NOH (X= H and 2-, 3- and 4-MeO): different conformations and hydrogen-bonding patterns

“…However, the involvement of weaker intermolecular interactions, such as C-HÁ Á ÁO hydrogen bonds,interactions and interactions involving the substituents, can have a significant influence on the supramolecular arrays generated. In a continuation of recent studies on aldoximes (Low et al 2018;Gomes et al, 2018), we have determined the crystal structures of four methoxybenzaldehyde derivatives, namely 2-MeO-X-C 6 H 3 CH NOH where X = H in 1, X = 3-MeO in 2, X = 4-MeO in 3 and X = 5-MeO in 4. The aim of the study was to further investigate the occurrence of R 2 2 (6) dimers and C(3) chains in a series of related compounds.…”