Spectroscopic and theoretical evidence for the elusive intermediate of the photoinitiated and thermal rearrangements of photochromic spiropyrans

Spectral properties and photochromic behavior of a series of novel 1',3',3'-trimethyl-1,2-tetramethylenespiro[7H-furo(3,2-f)-(2H-1)-benzopyran-7,2'-indolines] 1-4 have been studied. The mechanism of the photoinitiated ring-opening reaction involves the formation of an acoplanar cis-cisoid intermediate, the lifetime of which in the case of 6-(tert-butyl) derivative 4 is long enough to observe its absorption and fluorescence spectra under conditions of continuous irradiation. The occurrence of the intermediate on the reaction paths of the thermal and photochemical ring-opening processes has been also shown by the DFT and CIS calculations. The TD-B3LYP/6-31G//HF/6-31G calculated spectrum of the intermediate well matches that observed experimentally. For spiropyran 3 with a 6-NO(2) group, kinetic and activation parameters of the photoinitiated coloration and dark bleaching reactions have been determined.     

Spiropyrans and spirooxazines. 2. Synthesis,structures, and photochromic properties of 6"-cyano-substituted spironaphthooxazines

A series of 6"-cyano-substituted spiro[indoline-2,3"-naphtho[2,1-b]oxazines] containing substituents with carbon chains of different lengths in the indoline fragment were synthesized. The structure of one of these spironaphthooxazines was established by X-ray diffraction analysis. The influence of substituents on the photochromic properties of the resulting compounds in solutions and polymeric films was studied.     

A novel photoreversible photochromic system involving a hydrogen transfer/cyclization sequence

A novel photoreversible photochromic system, 3-(2-benzylbenzoyl)-1,2-R,R(1)-4(1H)-quinolinones/12-hydroxy-5-R-5a-R(1)-6-phenyl-5a,6-dihydrobenzo[b]acridin-11(5H)-ones, is described.     

Photochromic and thermochromic spiranes. 20.* Photochromic properties of solid-phase films of novel formyl-substituted spiropyrans of the indoline series

We have synthesized novel forrnyl-substituted spiropyrans of the indoline series. We have obtained solid phase amorphous films of the synthesized spiropyrans bv thermal vacuum deposition and established their capacity for photochrornic transformations. We have investigated the effect of the substituents on the spectral properties of the original and colored forms of the solid-phase spiropyran films. We have shown that the kinetic characteristics of the photochromic transformations of these compounds in solid-phase films depend considerably on the bulk of the substituents in the indoline and benzopyran moieties, and also their electron active properties in the latter. Along with reversible processes, in the solid-phase spiropyran films we have observed irreversible photoreactions leading to degradation of the photochromic system.Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-na-Donu 344090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 399–405, March, 1996. Original article submitted February 28, 1996.     

Spiropyrans and spirooxazines 12. Synthesis and complexation of a rhodamine-substituted spiro[benzopyran-indoline]

A new spirobenzopyranindoline containing a rhodamine fragment bonded by an azomethine spacer with the benzopyran fragment was synthesized based on 6-formyl-7-hydroxy-substituted spiropyran; the new compound exhibited complexation properties in solutions.     

Luminescence Determination of Copper(I), Silver(I), Gold(I), and Platinum(II) Using 2-Mercapto-5-Benzimidazolesulfonic Acid,also Immobilized on a Silica Surface

2-Mercapto-5-benzimidazolesulfonic acid (MBI), also noncovalently bound to a silica surface, is proposed as a reagent for the low-temperature luminescence determination of Cu(I), Ag(I), Au(I), and Pt(II). Luminescence excitation and luminescence spectra of metal complexes with MBI in solutions and on the adsorbent surface represent broad unstructured bands in the regions 250–400 and 450–700 nm, respectively. The developed procedures for the luminescence and sorption–luminescence determination of Cu, Ag, Au, and Pt with limits of detection at a level of 0.001–0.01 μg on 0.1 g of adsorbent are tested in the determination of metals in natural and industrial samples.     

Photo- and Ionochromic Spiroindoline-2,2′-pyrano[2,3-<Emphasis Type="Italic">f</Emphasis>]chromenecarbohydrazides—Chemosensors for Lanthanide Cations

Photochromic indoline spiropyrans with carbohydrazide substituents in the pyrano[2,3-f]chromene moiety of the molecule have been synthesized. These compounds exhibit inochromic properties and are chromogenic (“naked-eye”) and fluorogenic chemosensors for lanthanide cations.     

Inhibiting action of divalent copper compounds on microsomal oxidative demethylation of N,N-dimethylaniline

CuCl₂ is a non-competitive inhibitor whereas CuTyr₂ and CuLys₂ complexes are characterized by mixed-type inhibition. The inhibition action mechanism is discussed.

---

CuCl₂ , . .