IR spectrum of the closed form of indolinospironaphthooxazine

Abstract

UDC 543.42+535.34 IR absorption spectra of indolinospironaphthooxazine (ISNO) are presented. The geometric structure and normal coordinates of the ISNO molecule have been calculated using a quantum mechanical DFT method. The IR spectrum of ISNO in its original spiro form has been interpreted for the first time. Four normal modes in the range 800-1200 cm -1 with the largest amplitudes of C spiro -O bond change are identified. The excited ISNO molecule spiro form may experience photoconversion to the merocyanine form through them.Introduction. Organic photochromic materials hold great promise for application in molecular electronic devices and information processing systems. Factors hindering practical use of photochromic materials include their insufficient photochemical and thermal stability, a poor understanding of the course of molecular structural transformations during the photochromic process, and the fundamental stages in the mechanisms of the phenomenon. Obviously, these issues are interrelated [1][2][3][4][5]. The fabrication of molecular structures with increased photochemical stability such as indolinospirooxazine compounds has prompted researchers to study the photochromic effect in materials based on them [6][7][8][9][10][11].Optical and radiationless transitions in photochromic materials and the mechanisms of intra-and intermolecular interactions that determine the generation and decay of excitations in such molecules must be studied in order to understand thoroughly the photochromism phenomenon [5,11,12]. Information on the properties of vibrational states is important for investigating photochromism and deploying photo-and thermochromic materials because these states are actively involved in the absorption and dissipation of absorbed optical quanta [11,12]. A necessary step in studying the electronic and vibrational transitions is the determination of the characteristics of molecular normal modes (NMs) that are most active in optical and radiationless processes. This must begin with a theoretical and experimental study of the NMs of these molecules in the structure typical of the ground electronic state of the initial spiro form (closed form).Herein the IR spectrum of one of these compounds, indolinospironaphthooxazine (ISNO) or 1,3-dihydro-1,3,3-trimethylspiro[2H-indol-2,3′-[3H]naphtho[2,1-b][1,4]oxazine] [13], in the initial spiro form (Fig. 1) is studied and interpreted based on quantum-mechanical calculations using the DFT method.Experimental. ISNO was synthesized by the literature method [6]. IR spectra were recorded on Specord 75IR and Nexus FT-IR (Thermo Fisher Scientific, USA) spectrophotometers in the range 4000-400 cm -1 with spectral slit

Novel Photoactive Spirooxazine Based Switch@MOF Composite Materials

“…An exact assignment of all IR bands to the respective isomer (SP−O and MC−O, respectively) was performed for SP−O@MOF‐5. Following the work of Lyubimov and co‐workers and Paal and Arnold , the decreasing IR bands of the SP−O form were completely assigned for this system.…”

“…Moreover, increasing IR bands of 1 were also analysed. The assignments for the irradiated species are given in Table S3 (Supporting Information) according to Lyubimov and co‐workers and Paal and Arnold …”

“…also analysed. The assignments for the irradiated species are given in Table S3 (Supporting Information) according to Lyubimov and co-workers [64] and Paal and Arnold. [63] The unassigned vibrational frequencies were allocated according to a common textbook on spectroscopy.…”

Tracking the light-induced isomerization processes and the photostability of spiropyrans embedded in the pores of crystalline nanoporous MOFs via IR spectroscopy

“…Values marked with an "*" were taken from the theoretical and without an "*" from the experimental data of Nakata and co-workers. [55] Highlighted data represent the strongest bands with regard to intensity (bold: relative intensity > 30%; bold and underlined: intensity = 100%). Modes of vibrations were assigned according to Lyubimov and co-workers [55] , Paal and Arnold [56] and Hesse, Meyer & Zeeh [57] .…”

“…decreasing bands / cm -1 assignment / cm -1 vibration mode 1652 SP(1654) ν(C=C), ν(C=N) [56] 1610 SP(1615) ν(C=C), ν(C=N) [56] 1589/1578 SP(1583) ring-valence vibration ν(C=C) [56] 1517 SP(1508) ring-valence vibration ν(C=C) [56] 1479 SP(1482/1472) ring-valence vibration ν(C=C) [56] 1398 SP(1388) SP(1398) theoretical [55] :…”