Crystal Structure and Spectroscopic Properties of (2-oxo-2H-chromen-3-yl)phosphonic Acid Monoethyl Ester Trihydrate

Abstract

(2-Oxo-2H-chromen-3-yl)phosphonic acid monoethyl ester trihydrate (1) was synthesized, isolated, and spectroscopically as well as structurally characterized by means of single crystal X-ray diffraction; conventional and linear-polarized IR spectroscopy; electronic (UV-VIS-NIR) spectroscopy; ¹H, ¹³C, and ³¹P NMR. Quantum chemical DFT calculations have been performed in order to obtain information on the electronic structure and vibrational properties of 1, thus supporting the experimental data. The correlation between the structure and spectroscopic characteristics is discussed.

GRAPHICAL ABSTRACT      

Selective Reduction of ortho-Acylated β-Enaminones of Homoveratryamine and Their Cyclization to 1,2,3,4-Tetrahydroisoquinolines with β-Enaminone Moiety

Enaminones are very stable compounds and can be prepared from cheap and easily available starting materials. Therefore they are excellent starting materials in organic synthesis. The selective reduction of ortho-acylated β-enaminones under mild conditions, keeping the enaminone moiety intact, is reported. The appropriated conditions for cyclization of newly obtained hydroxienamides were found. Novel 1-substituted 1,2,3,4-tetrahydroisoquinolines with potential anticonvulsic activity were synthesized.     

Physical processes in azobenzene polymers on irradiation with polarized light

Azobenzenes can serve as model compounds for the study of transcis isomerization in more complex molecules. We have performed time-resolved spectroscopy in solutions containing free azobenzene chromophores and diols with a view to obtaining the energy levels and lifetimes of the excited states. A transition route based on experimental results for the theoretically calculated energy level scheme is proposed. Physical observations of surface relief in thin films of azobenzene polymers when irradiated with polarized light are reported. These include two beam polarization holographic observations and single beam transmission measurements through a mask, followed by atomic force microscope and profiler investigations. It is concluded that none of the prevalent theories can explain all the observed facts.