Specord 80

All of the reagents and solvents were obtained commercially and used without any additional purification. The assessment of the progress of reactions and purity of the synthesized compounds was performed using TLC on MERCK Silica gel 60 F254 plates, with hexane/acetone (1:2) as an eluent, and visualized under UV light. Melting points were determined using a METTLER TOLEDO™ Melting Point System MP70 apparatus. The IR spectrum was recorded on a Thermo Scientific Nicolet iS50 Spectrometer (ATR accessory; no. of scans: 64; resolution: 4; data spacing: 0.482 cm⁻¹). ¹H-, ¹³C-, and ³¹P-NMR were captured using a Bruker Avance 500 MHz (Bruker Corporation, Billerica, MA, USA) in CDCl₃ at room temperature. Solvent peaks were used as the internal reference. Chemical shift (δ) values are reported in ppm. Accurate high-resolution mass measurements were conducted using the Orbitrap Exploris 120 (Thermo Fisher Scientific, Waltham, MA, USA), operating in Full Scan mode at a resolution of 120,000. The FLSP920 spectrofluorometer (Edinburgh Instruments Ltd., Livingston, UK) captured fluorescence emission spectra within the visible range of 450–800 nm, while the absorption spectra were acquired using the UV-visible spectrophotometer SPECORD^® 80 (Analytik Jena AG, Jena, Germany).

Spectral parameters were measured in eight organic solvents: hexane, benzene, chloroform (CHCl₃), ethyl acetate (EtOAc), acetone, ethanol (EtOH), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and in PBS buffer (pH = 7.4) for solutions with concentrations 10⁻⁵ M at an ambient temperature in 10 mm quartz cuvettes. All solvents were of p.a. or analytical grade. The absorption spectra were obtained using a UV-visible spectrophotometer Specord^® 80 (Analytik Jena AG, Germany). The fluorescence emission spectra were recorded on an FLSP920 (Edinburgh Instruments Co., Ltd., Ediburgh, Scotland) spectrofluorometer using 3-methoxybenzanthrone (QS = 0.56 in acetone [42 (link)]) as the reference luminophore [43 ].

The spectral properties of the investigated compound were measured in benzene (C₆H₆), chloroform (CHCl₃), ethyl acetate (EtOAc), acetone, ethanol (EtOH), dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) with concentrations of 10⁻⁵ M at an ambient temperature in 10 mm quartz cuvettes. All solvents were of a p.a. or analytical grade. The absorption spectra were obtained using the UV-visible spectrophotometer SPECORD^® 80 (Analytik Jena AG, Jena, Germany). The fluorescence emission spectra were recorded on a FLSP920 (Edinburgh Instruments Ltd., Edinburgh, UK) spectrofluorometer in the visible range 500–800 nm.