N-(3-tert-Butyl-1-phenyl-1H-pyrazol-5-yl)-N-(4-methoxybenzyl)acetamide: a hydrogen-bonded chain of centrosymmetric rings

Abstract

The molecule of the title compound, C(23)H(27)N(3)O(2), adopts a conformation having no internal symmetry so that the compound exhibits conformational chirality. The molecules are linked by a combination of C-H...O and C-H...pi(arene) hydrogen bonds into a chain of rings in which two types of centrosymmetric ring alternate.

Hydrogen-bonding patterns in three substitutedN-benzyl-N-(3-tert-butyl-1-phenyl-1H-pyrazol-5-yl)acetamides

“…However, C-HÁ Á ÁN hydrogen bonds and aromaticstacking interactions are absent from the structures of all three compounds. While amide atom O58 acts as a hydrogen-bond acceptor in each of (I)-(III), as indeed it does in compound (IV) also (Castillo et al, 2010), different hydrogen-bond donors to O58 are active in each of (I)-(III). In compound (I) only the unsubstituted aryl ring acts as an acceptor of a C-HÁ Á Á(arene) hydrogen bond, but in compounds (II) and (III) both aryl rings accept hydrogen bonds.…”

“…Similarly, the pattern of the intermolecular hydrogen bonds is different in (I) and (II) leading to different forms of supramolecular aggregation, as discussed below, despite the fact that in neither compound does the substituent in question play any direct role in the intermolecular interactions. Compounds (I) and (IV) (Castillo et al, 2010) are even closer in similarity, differing only by the replacement of one of the acetyl H atoms in (IV) by a Cl atom in (I); these two compounds crystallize in the same space group, P1, with unitcell volumes which differ by less than 1%, while the corre-sponding unit-cell angles differ by less than 2 . However, unitcell vectors a and b are larger for (I) by ca 2.5 and 6.6%, while the unit-cell vector c is smaller for (I) by ca 7.1%.…”

“…The molecular conformations of compounds (I)-(III) can, apart from the carbonodithioate portion of compound (III), be defined in terms of a rather small number of torsion angles, and Table 1 lists the values of these angles along with the corresponding values for compound (IV) (Castillo et al, 2010). It is immediately evident that all four compounds adopt very similar conformations for their common fragments, with the exception of the orientation of the tert-butyl groups.…”

“…It is of interest briefly to compare the hydrogen-bonded structures of compounds (I) and (IV), particularly in view of the similarity in their unit-cell dimensions. In compound (IV) (Castillo et al, 2010), a chain of edge-fused centrosymmetric rings is generated by the combination of one C-HÁ Á ÁO hydrogen bond and one C-HÁ Á Á(arene) hydrogen bond, rather as in compound (I). However, the rings formed by the C-HÁ Á ÁO hydrogen bond are of R 2 2 (20) type in (IV) as opposed to R 2 2 (16) type in (I), and the chain runs parallel to [100] in (IV), i.e.…”

(E)-N2-{4-[(E)-2-(4-Chlorobenzoyl)ethenyl]-3-methyl-1-phenyl-1H-pyrazol-5-yl}-N1,N1-dimethylformamidine: polarized molecules within sheets of π-stacked hydrogen-bonded chains

“…In addition, the C52-N53 bond is significantly shorter than the N1-C5 bond. The C5-N51 and N51-C52 distances can be compared with the context-specific examples found in the series of simple Schiff bases, (II) (see scheme), where the substituent Ar represents a range of substituted phenyl, or exceptionally pyridyl, groups (Castillo et al, 2010). For the C5-N51 bond, 15 independent values in the series of compounds (II) range from 1.381 (4) to 1.401 (3) Å , all longer than the comparable bond in (I), while for the N51-C52 bond, the values in the series (II) span the range 1.268 (3)-1.294 (3) Å , all shorter than the corresponding bond in (I).…”