Optical Study of Solvatochromic Isocyanoaminoanthracene Dyes and 1,5-Diaminoanthracene

Abstract

Isocyanoaminoarenes (ICAAr-s) are a novel and versatile group of solvatochromic fluorophores. Despite their versatile applicability, such as antifungals, cancer drugs and analytical probes, they still represent a mostly unchartered territory among intramolecular charge-transfer (ICT) dyes. The current paper describes the preparation and detailed optical study of novel 1-isocyano-5-aminoanthrace (ICAA) and its N-methylated derivatives along with the starting 1,5-diaminoanthracene. The conversion of one of the amino groups of the diamine into an isocyano group significantly increased the polar character of the dyes, which resulted in a significant 50–70 nm (2077–2609 cm−1) redshift of the emission maximum and a broadened solvatochromic range. The fluorescence quantum yield of ICAAs is strongly influenced by the polarity of the solvent. The starting anthracene-diamine is highly fluorescent in every solvent (√f = 12–53%), while the isocyano derivatives are practically nonfluorescent in solvents more polar than dioxane. This phenomenon implies the potential application of ICAAs to probe the polarity of the medium and is favorable in practical applications, such as cell-staining, resulting in a reduced background fluorescence. The ICT character of the emission states of ICAAs are in good agreement with the computational findings presented in TD-DFT calculations and molecular electrostatic potential (MESP) isosurfaces.

Activating two-dimensional semiconductors for photocatalysis: a cross-dimensional strategy

“…After years of development, TD-DFT can not only work well on small to medium sized molecules, but also works on more complex structures. Various optical properties have been calculated for dyes for solar cells [334][335][336], complexes on gas sensors [337], and transition metal-radical ligand complexes [338] etc. To extend the applicability of TD-DFT, memory functionals were invented, which considers the time evolution of the past densities, hence more problem can be solved [329].…”

Optical Investigation of 2-amino-7-isocyanofluorene, a Novel Blue-Emitting Solvatochromic Dye

“…To overcome this issue, one may use two-photon excitation [13], or more favorably the exchange of the fluorochromic core, this way increasing the polarization axis and the dipole moment change of the dye. Using the second approach to enhance the optical properties of the PRODAN and ICAN families, pyrene [14], anthracene (Anthradan) [15,16] and acridine (2,7-ICAAc) [17] derivatives were also prepared from both dye families. Indeed, the solvatochromic range was significantly redshifted and the isocyanoacridine derivatives turned out to be promising photodynamic anticancer agents [17].…”

Preparation and Optical Study of 1-Formamido-5-Isocyanonaphthalene, the Hydrolysis Product of the Potent Antifungal 1,5-Diisocyanonaphthalene

“…Utilizing the strong electron withdrawing (EW) nature of the isonitrile group, Nagy et al recently developed a novel class of push-pull fluorophores, where the isocyanide group is connected to an aromatic amine [11][12][13][14][15][16][17][18][19][20][21][22]. The resulting intramolecular charge transfer (ICT) gives rise to excellent solvatochromic properties, as we previously demonstrated through 1-amino-5-isocyanonaphthalene (ICAN) [11].…”

“…The resulting intramolecular charge transfer (ICT) gives rise to excellent solvatochromic properties, as we previously demonstrated through 1-amino-5-isocyanonaphthalene (ICAN) [11]. The spectrophysical properties are easily controlled by the relative positions of the -NH2 and -NC groups [12], as well as the substituents (reactive [14,16] or inert [13,18,22]) on the -NH2 group or by exchanging the aromatic core [19][20][21]. The synthesis of ICAN derivatives is cheap and straightforward since the respective aromatic diamine is reacted smoothly with in situgenerated dichlorocarbene (:CCl2) in basic solution [11].…”