Synthesis of novel π-extended D–A–D-type dipyrido[3,2-a:2′,3′-c]phenazine derivatives and their photosensitized singlet oxygen generation

Abstract

Electron donor–acceptor–donor (D–A–D) π-conjugated molecules based on dipyrido[3,2-a:2′,3′-c]phenazine (dppz) were developed as photosensitizers for singlet oxygen generation.

One pot three component synthesis of DNA targeting phototoxic Ru(ii)-p-cymene dipyrido[3,2-a:2′,3′-c]phenazine analogues

“…33 However, on photoexcitation with visible light the ruthenium dppz complexes enable the abstraction of an electron from the 'd' orbital of the ruthenium centre which is then shifted to a π* orbital of the dppz ligand, resulting in the development of a long-lived 3 MLCT state which includes the initial population of 1 MLCT on the bipyridine portion of the dppz ligand, followed by intraligand electron transfer to the pyrazine moiety. 34 After that, again the formation of 3 MLCT at the phenazine-based pyrazine moiety of the dppz ligand may perhaps be the main cause of their exceptionally strong luminescence properties. 35,36 Herein, we wish to explore a novel series of substituted dipyrido[3,2-a:2′,3′-c]phenazine (dppz) based ruthenium(II)-p-cymene complexes as a potential delegate in the field of photoinduced cancer treatment.…”

Synthesis and optical properties of phenazinone-based photosensitizers for singlet oxygen generation

“…In order to clarify the optical factors affecting the Φ Δ values, we investigated the photophysical processes of the phenazinone-based PSs PZ1–3 for 1 O 2 generation. In this context, the radiative ( k r ) and nonradiative ( k nr ) decay rate constants were evaluated from the Φ fl and fluorescence lifetime ( τ fl ) values (Table 1) according to eqn (1) and (2): 22 k r = Φ fl / τ fl k nr = (1 − Φ fl )/ τ fl In addition, the ISC ( k ISC ) and IC ( k IC ) rate constants were also evaluated according to eqn (3) and (4): k ISC = Φ T / τ fl k nr = k IC + k ISC where the triplet generation quantum yield ( Φ T ) was approximated by Φ Δ . 23 Table 2 summarizes the values of k r , k nr , k ISC , and k IC for PZ1–3 .…”

Synthetic strategies of phenazine derivatives: A review

“…In 2014, Tandon and co-workers [79] reported an efficient and concise one-pot regio-and chemo-selective synthesis of benzo[a]phenazine and derivatives (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). As shown in Scheme 3, this method was employed for 2, 3-dichloro-1, 4-naphoquinone to nucleophile with ophenylenediamine and benzamidine under the condition of H 2 O in the presence of alkali and micelles (SDS) as catalysts, achieving the expected products in excellent yields.…”

“…Phenazine is an important class of nitrogen-containing heterocycles endowing particular backbone structure with electron-deficient π system and lone pair electrons on N atoms [1][2][3][4][5][6][7]. It has been widely explored in the fields of medicine, pesticides, dyes, and conductive materials [5,[8][9][10][11][12][13][14]. Since then, a plenteous of phenazine derivatives have been synthesized and identified due to their attractive performance [15][16][17][18][19].…”