Spectroscopy and Reactivity of Dialkoxy Acenes

Abstract

Photochemical oxidation of acenes can benefit or impedet heir function, depending on the application.A lthougha cenes with alkoxy substituents on reactive sites are important for applications as diverseasdrug delivery and organic optoelectronics, the influence of chemical structure on their photochemical oxidation remainsu nknown. This paper therefore describes the synthesis, spectroscopic properties, and reactivity with singlet oxygen ( 1 O 2 )o faseries of dialkoxyacenest hat varyi nt he number and types of fused rings in the (hetero)acene cores. Reductive alkylationofquinone precursorsy ieldedt arget dialkoxyacenesw ith fused backbones rangingf rom benzodithiophene to tetracenothiophene. Trends of their experimental spectroscopicc haracteristics were consistent with time-dependent density functional theory( TD-DFT) calculations.N MR studies show that photochemically generated 1 O 2 oxidizes all but one of these acenest ot he corresponding endoperoxidesi no rganic solvent. The rates of these oxidations correlate with the number and types of fused arenes,w ith longer dialkoxyacenesg enerally oxidizing faster than shorterd erivatives. Finally,i rradiation of these acenes in acidic, oxidizing environmentsc leavest he ether bonds. This work impacts those workingi no rganic optoelectronics, as well as those interested in harnessing photogenerated reactive oxygen speciesi n functional materials.[a] Dr.

In Situ Reduction and Functionalization of Polycyclic Quinones

“…Samples of 9 freshly prepared from crystalline material exhibit a clean 1 H NMR spectrum. After light exposure, these original resonances disappear and peaks resembling literature spectra for the endoperoxide decomposition product are observed (see the Supporting Information). Drop-cast films showed improved photostability over dilute solutions but were eventually bleached in direct sunlight over tens of hours.…”

“…In photovoltaic materials, alkyl or alkoxy chains are more common as less crystalline materials are preferable to allow suitable mixing between donor and acceptor phases. Direct conversion of quinones to alkoxy acenes was reported by Brega et al, with the resulting products exhibiting properties relevant to oxygen sensing or photodynamic drug delivery. Commonly used as PAH precursors, polycyclic quinones are themselves highly coveted functional materials due to their redox properties and applicability to redox flow batteries …”

Superhydrophobic Surfaces as a Source of Airborne Singlet Oxygen through Free Space for Photodynamic Therapy

“…8 In a water droplet, 1 O readily oxidizes at the 9,10-position by a [4 + 2] reaction. The [4 + 2] reaction of 1 O 2 is a common reaction in the field, 12,[16][17][18][19][20] although it is usually monitored in the solution phase with a solvated sensitizer, which is unlike our SH sandwich system with a physically separated sensitizer.…”

“…In a water droplet, 1 O 2 readily oxidizes 1 at the 9,10-position by a [4 + 2] reaction. The [4 + 2] reaction of 1 O 2 is a common reaction in the field, ,− although it is usually monitored in the solution phase with a solvated sensitizer, which is unlike our SH sandwich system with a physically separated sensitizer. The physical quenching ( k q ) and chemical quenching ( k r ) of 1 O 2 by 1 are shown in eqs and . The use of 1 enables us to monitor the rate of 1 O 2 capture in the water droplet to be estimated by the reduction of the concentration of 1 .…”

Two Anthracene-Based Ir(III) Complexes [Ir(pbt)2(aip)]Cl and [Ir(pbt)2(aipm)]Cl: Relationship between Substituent Group and Photo-oxidation Activity as Well as Photo-oxidation-Induced Luminescence

“…Anthracene and its derivatives have fascinating physical and chemical properties, such as luminescence, − [4π + 4π] photodimerization, and photo-oxidation (Scheme S1). , It is more interesting that some metal complexes incorporate anthracene moieties, thus showing functionality modulation/switching. For example, the Liu group recently reported a supramolecular assembly from ϒ-cyclodextrin, 4-(anthracen-2-yl)­pyridine-2,6-dicarboxylic acid, and Eu­(III), which shows emission switching from blue-light emission of the anthracene-based ligand to red-light emission of the Eu­(III) fragment upon irradiation with 365 nm light .…”