9-Phenyl-10H-acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C19H14N+·CF3SO3 −, the cations are linked to each other by very weak C—H⋯π inter­actions, while the cations and anions are connected by N—H⋯O, C—H⋯O and S—O⋯π inter­actions. The acridine ring system and the phenyl ring are oriented at an angle of 80.1 (1)° with respect to each other. The mean planes of adjacent acridine units are either parallel or inclined at an angle of 35.6 (1)°. The trifluoro­methane­sulfonate anions are disordered over two positions; the site occupancy factors are 0.591 (8) and 0.409 (8)

9-(Methyl­sulfan­yl)acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C14H12NS+·CF3SO3 −, N—H⋯O hydrogen bonds link cations and anions into ion pairs. Inversely oriented ion pairs form stacks through multidirectional π–π inter­actions among the acridine units. The crystal structure features a network of C—H⋯O inter­actions among stacks and also long-range electrostatic inter­actions among ions. In the packing of the mol­ecules, the acridine units are nearly parallel in stacks or inclined at an angle of 33.07 (2)° in the four adjacent stacks with which they inter­act via weak C—H⋯O inter­actions. The methyl­sulfanyl group is twisted through an angle of 60.53 (2)° with respect to the acridine ring

2-Meth­oxy-9-phenoxy­acridine

The mol­ecules in the crystal structure of the title compound, C20H15NO2, form inversion dimers connected through the C—H⋯N and π–π inter­actions. These dimers are further linked by C—H⋯π inter­actions. The meth­oxy group is nearly coplanar with the acridine ring system [dihedral angle = 4.5 (1)°], whereas the phen­oxy fragment is nearly perpendicular to it [dihedral angle = 85.0 (1)°]. The mean planes of the acridine ring systems are either parallel or inclined at angles of 14.3 (1), 65.4 (1) and 67.3 (1)° in the crystal

9-Ethyl-10-methyl­acridinium trifluoro­methane­sulfonate

In the mol­ecule of the title compound, C16H16N+·CF3SO3 −, the central ring adopts a flattened-boat conformation, and the two aromatic rings are oriented at a dihedral angle of 3.94 (2)°. In the crystal structure, weak inter­molecular hydrogen bonds link the mol­ecules. There are π–π contacts between the aromatic rings and the central ring and one of the aromatic rings [centroid–centroid distances = 3.874 (2), 3.945 (2) and 3.814 (2) Å]. There is also an S—O⋯π contact between the central ring and one of the O atoms of the anion

9-Benzyl-10-methyl­acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C21H18N+·CF3OS3 −, the cations form inversion dimers through π–π inter­actions between the acridine ring systems. These dimers are further linked by C—H⋯π inter­actions. The cations and anions are connected by C—H⋯O, C—F⋯π and S—O⋯π inter­actions. The acridine and benzene ring systems are oriented at a dihedral angle of 76.8 (1)°with respect to each other. The acridine moieties are either parallel or inclined at an angle of 62.4 (1)° in the crystal structure

9-Chloro-2,4-dimethoxy­acridinium trifluoro­methane­sulfonate

In the mol­ecular structure of the title compound, C15H13ClNO2 +·CF3SO3 −, the meth­oxy groups are nearly coplanar with the acridine ring system, making dihedral angles of 0.4 (2) and 5.1 (2)°. Multidirectional π–π contacts between acridine units are observed in the crystal structure. N—H⋯O and C—H⋯O hydrogen bonds link cations and anions, forming a layer structure

Computational Insights on the Mechanism of the Chemiluminescence Reaction of New Group of Chemiluminogens—10-Methyl-9-thiophenoxycarbonylacridinium Cations

Immunodiagnostics, in which one of the promising procedures is the chemiluminescent labelling, is essential to facilitate the detection of infections in a human organism. One of the standards commonly used in luminometric assays is luminol, which characterized by low quantum yield in aqueous environments. Acridinium esters have better characteristics in this topic. Therefore, the search for new derivatives, especially those characterized by the higher quantum yield of chemiluminescence, is one of the aims of the research undertaken. Using the proposed mechanism of chemiluminescence, we examined the effect of replacing a single atom within a center of reaction on the efficient transformation of substrates into electronically excited products. The density functional theory (DFT) and time dependent (TD) DFT calculated thermodynamic and kinetic data concerning the chemiluminescence and competitive dark pathways suggests that some of the scrutinized derivatives have better characteristics than the chemiluminogens used so far. Synthesis of these candidates for efficient chemiluminogens, followed by studies of their chemiluminescent properties, and ultimately in chemiluminescent labelling, are further steps to confirm their potential applicability in immunodiagnostics

Tautomerism and Behavior of 3‑Hydroxy-2-phenyl‑4<i>H</i>‑chromen-4-ones (Flavonols) and 3,7-Dihydroxy-2,8-diphenyl‑4<i>H</i>,6<i>H</i>‑pyrano[3,2‑<i>g</i>]chromene-4,6-diones (Diflavonols) in Basic Media: Spectroscopic and Computational Investigations

Absorption and emission spectroscopic investigations and computational predictions have shown that neutral molecules of flavonols and diflavonols can exist in the ground and excited states in one or two tautomeric forms stabilized by intramolecular (in aprotic media) or intermolecular (with solvent molecule(s), in protic media) hydrogen bonds. Electronic excitation creates conditions for the transformation of tautomeric forms, accompanied by proton transfer, reflected in fluorescence spectra. Proton transfer is also probable in monoanions of diflavonols in protic media. The OH groups involved in hydrogen bonds exhibit a proton-donating ability characterized by the respective acidity constants. The electronically excited diflavonols are relatively strong acids if they lose one proton. With increasing basicity of the medium, anionic forms occur, which exhibit spectral characteristics and emission abilities different from those of neutral molecules. These features open up possibilities for the analytical use of these compounds as spectral probes sensitive to the properties of liquid phasesfrom neutral to strongly basic. The less intensively studied diflavonols seem to be more promising than flavonols for these purposes, since they are more lipophilic, polarizable, polar, and sensitive to basic features of the environment