Crystal structure and lattice energetics of 10-methylacridinium halides

Abstract

The crystal structures of 10-methylacridinium chloride monohydrate, bromide monohydrate and iodide were determined by X-ray analysis. The compounds crystallize in the triclinic space group, P¯1, with 2 molecules in the unit cell. The molecular arrangement in the crystals revealed that hydrogen bonds (in hydrates) and van der Waals contacts play a significant part in intermolecular interactions. To discover their nature, contributions to the crystal lattice energy arising from electrostatic (the most important since the compounds form ionic crystals), dispersive and repulsive interactions were calculated. Enthalpies of formation of the salts, their stability and susceptibility to decomposition could be predicted from a combination of crystal lattice energies with values of other thermochemical characteristics obtained theoretically or taken from the literature. The role of water in the stabilization of the crystal lattice of the hydrates is also explained. The information gathered has given an insight into the features and behaviour of compounds which can be regarded as models of a large group of aromatic quaternary nitrogen salts.

9-(Methylsulfanyl)acridinium trifluoromethanesulfonate

“…In the cations of the title compound ( Fig. 1), the bond lenghts and angles characterizing the geometry of the acridine skeleton are typical of acridine-based derivatives (Storoniak et al, 2000;Meszko et al, 2002;Mrozek et al, 2002). The C9-S15 and S15-C16 bond lengths (1.754 (3) Å and 1.807 (4) Å, respectively) correlate well with those reported for 9-(thio-2′-methyl-4′-nitrophenyl)acridine (Mrozek et al, 2002).…”

“…For general background, see: Wró blewska et al (2004) ;Zomer & Jacquemijns (2001). For related structures, see: Meszko et al (2002); Mrozek et al (2002); Storoniak et al (2000). For molecular interactions, see: Aakerö y et al (1992); Bianchi et al (2004); Hunter et al (2001); Spek (2009) ;Steiner (1991).…”

10-Methyl- and 9,10-dimethylacridinium methyl sulfate

“…Atoms C9 and N10, as well as the methyl group in the cation, are arranged in an almost linear fashion [C9Á Á ÁN10ÐC15 = 178.0 (2) ]. The methyl group in the cation is ®xed in a certain position, as in 10-methylacridinium halides (Storoniak et al, 2000). The methyl group of the anion is similarly ®xed; this is not the case in (II).…”

“…Methylation of acridines is the simplest way of converting them into stable cationic forms (Storoniak et al, 2000) which are fairly readily soluble in water. Unlike their protonated forms, methylated acridines are resistant to changes in pH and are thus convenient derivatives for numerous applications.…”

9-Cyano-10-methylacridinium hydrogen dinitrate

“…The H atoms of the methyl group occupy two orientations, each with occupancy 0.5. This is typical of compounds in which the H atoms of the methyl group do not interact with the O atoms of the anions, unlike the 10-methylacridinium halides, where CÐH interactions with anions ®x the methyl group in one position (Storoniak et al, 2000). The central N1ÐO1Á Á ÁH1BÁ Á ÁO1 iii ÐN1 iii moiety of the hydrogen dinitrate anion appears to be planar, as in other inorganic (Duke & Llewellyn, 1950;Faithful & Wallwork, 1967;Roziere et al, 1976) and organic (Al-Zamil et al, 1982;Roziere et al, 1979) compounds containing this anion [symmetry code: (iii) Àx, Ày, Àz].…”