Crystal structure of 3-amino-1-propyl-pyridinium bromide

Synthesis, intermolecular interactions and biological activities of two new organic-inorganic hybrids C6H10N2,2Br and C6H10N2,2Cl·H2O

A slow evaporation method has permitted the crystallization of two novel crystals of (2-aminomethyl)pyridindiumdihalide C₆H₁₀N₂,2Br (1) and C₆H₁₀N₂,2Cl·H₂O (2). The structures of the prepared compounds (1) and (2) were elucidated by single-crystal X-ray diffraction which revealed that they crystallize, respectively, with triclinic and monoclinic symmetries. Their crystal packing was stabilized by non-covalent interactions, including N–H⋯Br, C–H⋯Br, N–H⋯Cl, O–H⋯Cl and N–H⋯O hydrogen bonds. 3-D Hirshfeld surface analysis followed by 2-D fingerprint schemes gives insights into the intermolecular interactions in the crystalline structure. Furthermore, the FT-IR spectroscopy of these two compounds was carried out. The synthesized products were also screened for in vitro antioxidant and antimicrobial activities, which reveals their favourable antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as the discolouration of β-carotene.

A slow evaporation method has permitted the crystallization of two novel crystals of (2-aminomethyl)pyridindiumdihalide C₆H₁₀N₂,2Br (1) and C₆H₁₀N₂,2Cl·H₂O (2).

Experimental and Theoretical Insights into the Optical Properties and Intermolecular Interactions in Push-Pull Bromide Salts

Experimental and theoretical insights into the nature of intermolecular interactions and their effect on optical properties of 1-allyl-4-(1-cyano-2-(4-dialkylaminophenyl)vinyl)pyridin-1-ium bromide salts (I and II) are reported. A comparison of optical properties in solution and in the solid-state of the salts (I and II) with their precursors (Ia and IIa) is made. The experimental absorption maxima (λmax) in CHCl3 is at 528 nm for I and at 542 nm for II, and a strong bathochromic shift of ∼110 nm is observed for salts I and II compared with their precursors. The absorption bands in solid-state at ∼627 nm for I and at ∼615 nm for II that are assigned to charge transfer (CT) effect. The optical properties and single crystal structural features of I and II are explored by experimental and computational tools. The calculated λmax and the CT are in good agreement with the experimental results. The intermolecular interactions existing in the crystal structures and their energies are quantified for various dimers by PIXEL, QTAIM and DFT approaches. Three types of interactions, (i) the cation⋅⋅⋅cation interactions, (ii) cation⋅⋅⋅anion interactions and (iii) anion⋅⋅⋅anion interactions are observed. The cationic moiety is mainly destabilized by C-H⋅⋅⋅N/π and π⋅⋅⋅π interactions whereas the cation and anion moiety is predominantly stabilized by strong C-H⋅⋅⋅Br- interactions in both structures. The existence of charge transfer between cation and anion moieties in these structures is established through NBO analysis.