Direct and Indirect Chemiluminescence: Reactions, Mechanisms and Challenges

Emission of light by matter can occur through a variety of mechanisms. When it results from an electronically excited state of a species produced by a chemical reaction, it is called chemiluminescence (CL). The phenomenon can take place both in natural and artificial chemical systems and it has been utilized in a variety of applications. In this review, we aim to revisit some of the latest CL applications based on direct and indirect production modes. The characteristics of the chemical reactions and the underpinning CL mechanisms are thoroughly discussed in view of studies from the very recent bibliography. Different methodologies aiming at higher CL efficiencies are summarized and presented in detail, including CL type and scaffolds used in each study. The CL role in the development of efficient therapeutic platforms is also discussed in relation to the Reactive Oxygen Species (ROS) and singlet oxygen (1O2) produced, as final products. Moreover, recent research results from our team are included regarding the behavior of commonly used photosensitizers upon chemical activation under CL conditions. The CL prospects in imaging, biomimetic organic and radical chemistry, and therapeutics are critically presented in respect to the persisting challenges and limitations of the existing strategies to date.

Спектрально-люминесцентные свойства циклометаллированных комплексов Pd(II) на основе метилового эфира цинхофена

A procedure of synthesis of Pd (II) complexes with 2-phenylquinoline-4-carboxylic acid methyl ester: [PdMpqc(μ-Аc)]2 and [PdEnMpqc] BF4, where Mpqc is methyl 2-phenyl-4-quinolinecarboxylate ion, Ac - acetate ion, En - ethylenediamine, was developed. The composition and structure of the complexes obtained were established on the basis of IR and polynuclear NMR spectroscopy data, optical and physical properties were described on the basis of UV and fluorescence spectroscopy. The phosphorescence of Pd (II) complexes in the visible region was assigned to the radiative transition from the spin-forbidden intraligand electronically excited state 3(π-π) that is localized on the aromatic Mpqc system.

Studies of the First Electronically Excited State of 3-Fluoropyridine and its Ionic Structure by Means of REMPI, Two-Photon MATI, One-Photon VUV-MATI Spectroscopy and Franck-Condon Analysis

3-Fluoropyridine (3-FP) has been investigated by means of two-photon resonance-enhanced multi photon ionization (REMPI), mass-analyzed threshold ionization (MATI) and one-photon vacuum-ultraviolet (VUV) MATI spectroscopy. The aim was the determination of...

Photogeneration of Organic Free Radicals in Liquid Solutions

In this brief review we consider the generation of free radicals by irradiation with UV-light solutions of compounds with weak chemical bonds. Bond dissociation energies (BDE) are compared with the energies of photons. Light sources used in industry and academia are listed. Free radicals can be produced by photodissociation and by bimolecular chemical reactions between the electronically- excited state of a molecule and a quencher. Important examples are presented. A special effort is devoted to light-emitting diodes (LED) which gain a wide application in this century. We cited books on the free radicals and photochemistry as an introduction as well as recent publications dated 2020.