Structural studies of benzene derivatives. IX. The structures of p-fluoroaniline and p-cyanoaniline hydrochlorides

The subtle balance of weak supramolecular interactions: The hierarchy of halogen and hydrogen bonds in haloanilinium and halopyridinium salts

“…Halogen bonding is evident only in the structure of 4-IPhNH 3 Cl ( 1 ; Fig. 2), but weak halogen bonding Br···Cl − is observed in 4-BrPhNH 3 Cl ( 2 , TAWRAL [39]; Fig. 2) as well.…”

“…In 4-ClPhNH 3 Cl ( 3 , CURGOL [39]; Fig. 2), distance Cl···Cl − is slightly longer than Br···Cl − and the sum of VDW radii [17,44].…”

“…The measured X···Cl − distances, angles and other pertinent structural data are given in Table 1. At variance with the other members of the series, the structure of fluoro-substituted anilinium chloride 4 [39] is completely different (Fig. 2) and does not show similar hydrogen bonding and no halogen bonding and thus it was excluded from Table 1.…”

“…The structures of salts 4-BrPhNH 3 Cl ( 2 , CCDC ref. code TAWRAL) [37], 4-ClPhNH 3 Cl ( 3 , CURGOL) [38], 4-FPhNH 3 Cl ( 4 , ANLCLA) [39], 4-BrPhNH 3 H 2 PO 4 , ( 7 , UGISEI) [40], 3-BrPyHCl, ( 11 , CIHBAX) [41] and 3-ClPyHCl, ( 12 , VOQMUJ) [42] were extracted from the CSD [43] in order to obtain the full homogeneous series.…”

Crystal Structure and Optical Properties of a Lanthanum(III) Complex of the Solvatochromic Dye “Nile Red”

“…Secondly, the N1-C8 and N3-C31 bond lengths of 1.353(3) and 1.330(3) Å, respectively, are significantly shorter than expected for a N(sp 3 )-C(sp 2 ) bond (1.467(2) Å in 4-aminobenzonitrile hydrochloride). [8] This can be rationalized if we take the ionic resonance structure shown in Figure 3 into account. Here, the lone pairs of electrons on N1 and N3 reside in a pure p orbital which is conjugated with the aromatic ring; this results in an increased order of the N1-C8 and N3-C31 bond and delocalization of a negative charge on the β-keto ester group, as shown in Figure 3.…”