Light-induced tautomerism of β-dicarbonyl compounds

Abstract

This was the earliest in a long series of examples that were to prove the versatility and generality of the phenomenon. Later, the concept of tautomerism was extended to comprise all types of rapidly and reversibly equilibrated transformations (see, for examples, refs. 2 and 3).Since these early days the tautomeric equilibria in solutions of /I-dicarbonyl compounds have been the subject of continuous interest. Various aspects of this subject have received extensive treatment in several review articles.'-The group of /3-dicarbonyls comprises compounds such as (a), (b), and (c).

Synchronous fluorescence spectroscopic study of solvatochromic curcumin dye

“…The relative contributions of the keto and enolic tautomers as well as their cis or trans form depend on factors such as solvent characteristics, temperature, polarity and substitution on curcumin [17][18][19]. However, at room temperature, the enolic form of diketones is in general predominant [19][20][21]. Curcumin absorbs in the visible region and gives fluorescence with low quantum yield.…”

From I‐Ligated and I‐Doped to O‐Ligated Hafnium(IV) Phthalocyaninate(2–) Complexes

“…However the solvated acacH molecule exists in the keto form in crystal 1, whereas both acacH molecules in crystal 2 exist in the enol tautomeric form ( Figure 1). N1,C(1-8), N3,C(9-16), N5,C (17)(18)(19)(20)(21)(22)(23)(24) and N7,C(25-32) are inclined to the N 4 -isoindole plane defined by the N1, N3, N5 and N7 atoms by 8.8(1), 15.4(1), 13.2(1) and 13.4(1)°, respectively, in crystal 1 and by 11.2(1), 6.0(1), 15.9(1) and 8.0(1)°, respectively, in crystal 2. The respective dihedral angles that describe the distortion of the antiprism polyhedron around the Hf cation differ slightly from the expected value of 45°that is expected for an ideal antiprism.…”

Dissociative and Photochemical Mechanisms of Intramolecular Tautomerism

“…For other compounds of this series, the a-cleavage mechanism with the formation of a radical pair retains its importance in the forward as well as reverse reactions [30,31].…”