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Luminol is a prominent chemiluminescent (CL) agent, finding applications across numerous fields, including forensics, immunoassays, and imaging. Different substitution patterns on the aromatic ring can enhance or decrease its CL efficiency. We herein report a systematic study on the synthesis and photophysics of all possible 6,8-disubstituted luminol derivatives bearing H, Ph, and/or Me substituents. Their CL responses are monitored at three pH values (8, 10, and 12), thus revealing the architecture with the optimum CL efficiency. The most efficient pattern is used for the synthesis of a strongly CL luminol derivative, bearing a functional group for further, straightforward derivatization. This adduct exhibits an unprecedented increase in chemiluminescence efficiency at pH = 12, pH = 10, and especially at pH = 8 (closer to the biologically relevant conditions) compared to luminol. Complementary work on the fluorescence of the emissive species as well as quantum chemistry computations are employed for the rationalization of the observed results., The authors would like to thank Ekaterini Bouga and Christina-Ioanna Vrettou for assisting with certain synthesis steps. This project was financially supported by the European Union’s Horizon 2020 framework program for research and innovation under Grant Agreement No. 712921. T.M. and A.P. would like to thank the State Scholarships Foundation (IKY) for financial support via Ph.D. fellowships through the “Strengthening of Human Resources through Doctoral Research” program of the Operational Program “Human Resource Development, Education and Lifelong Learning” 2014–2020, co-financed by the European Union (European Social Fund ESF) and Greek national funds. The authors would also like to thank Prof. N. Thomaidis and Dr. Maria-Christina for the HRMS analyses. M.A.M. and G.M.R.-M. thank the Generalitat Valenciana (Prometeo Program/2017/075) for financial support. A.G. and D.R.-S. acknowledge Spanish “Ministerio de Ciencia e Innovación (MICINN)” (Project Ref CTQ2017-87054-C2-2-P). A.G. is also thankful to the MICINN for a “Juan de la Cierva” grant (Ref IJC2018-035123-I). D.R.-S. is also thankful to the MICINN for a “Ramón y Cajal” grant (Ref RYC-2015-19234) and to the BBVA Foundation for a 2019 Leonardo Grant for Researchers and Cultural Creators.

The preparation of an entirely supramolecular, multichromophoric azaborondipyrromethene (ABDP)/zinc tetraphenylporphyrin (ZnTPP)/exfoliated graphene (GR) nanoensemble was accomplished. The ABDP derivative bears glycol chains for enhancing solubility and a pyridine functionality for allowing coordination with ZnTPP. The ABDP/ZnTPP/GR nanoensemble was characterized in terms of morphology and composition by using complementary microscopy imaging, thermogravimetric analysis, Raman as well as steady-state and time-resolved absorption and emission spectroscopy. The photophysical and electrochemical assessment of ABDP/ZnTPP/GR as well as the binding properties of the ABDP/ZnTPP complex, employed as a reference, are presented. Energy and electron transfer events were observed in ABDP/ZnTPP upon photoexcitation. However, in the case of ABDP/ZnTPP/GR, the graphene-induced aggregation of the chromophores alters their electronic interactions, enhancing the energy/electron transfer process between them.

[EN] The monitoring of reactive oxygen species in living cells provides valuable information on cell function and performance. Lately, the development of chemiluminescence-based reactive oxygen species monitoring has gained increased attention due to the advantages posed by chemiluminescence, including its rapid measurement and high sensitivity. In this respect, specific organelle-targeting trackers with strong chemiluminescence performance are of high importance. We herein report the synthesis and chemiluminescence properties of eight novel phosphonium-functionalized amino-acylated luminol and isoluminol derivatives, designed as mitochondriotropic chemiluminescence reactive oxygen species trackers. Three different phosphonium cationic moieties were employed (phenyl, p-tolyl, and cyclohexyl), as well as two alkanoyl chains (hexanoyl and undecanoyl) as bridges/linkers. Synthesis is accomplished via the acylation of the corresponding phthalimides, as phthalhydrazide precursors, followed by hydrazinolysis. This method was chosen because the direct acylation of (iso)luminol was discouraging. The new derivatives' chemiluminescence was evaluated and compared with that of the parent molecules. A relatively poor chemiluminescence performance was observed for all derivatives, with the isoluminol-based ones being the poorest. This result is mainly attributed to the low yield of the fluorescence species formation during the chemiluminescence oxidation reaction., This project was financially supported by the European Union's Horizon 2020 framework program for research and innovation under grant agreement no. 712921, as well as a Greek State Scholarships Foundation (I.K.Y.) fellowship to A.P.

The use of co-adsorbents in dye-sensitized solar cells (DSCs) increases both the power-conversion efficiency and long-term stability of these devices. Co-adsorbents usually consist of a hydrophobic moiety attached on a carboxylic or phosphoric acid terminal anchoring group, which chemisorbs on the semiconductor surface. In this work, the synthesis of a new family of 8-quinolinol derivatives bearing alkyl chains of variable length at the 5-position is described and their comparative efficiency as effective bidentate co-adsorbents in DSCs is evaluated. The key step towards their straightforward modular synthesis is a Suzuki coupling between 5-chloro-8-methoxyquinoline and alkyltrifluoroborates. The new compounds showed better performance as co-adsorbents in terms of cell efficiency as compared to their alkylcarboxylic acid analogues, with the best results obtained from the derivative bearing the longer dodecyl alkyl chain.

The synthesis of novel pyrrolo[1,2-c][1,3]benzodiazepine and pyrrolo[3,2-c]- [1]benzazepine ring systems from (2-aminophenyl)(1H-pyrrol-2-yl)methanone and 2-[(1H-pyrrol-2-yl)methyl]aniline is presented, utilizing triphosgene as carbonylation-cyclization reagent for the formation of the 7-membered heterocycle. A study of the reaction shows that small changes in the reaction conditions affect dramatically the course of the reaction. Acidity as well as aqueous workup play significant roles in the reaction outcome, directing product formation and revealing important aspects of triphosgene mediated cyclizations.

Energy conversion schemes have attracted considerable attention in recent years. A large amount of research effort has focused on fullerenes, particularly C60 and its derivatives, as suitable electron acceptors, owing to their outstanding properties. In this context, C59 N-based donor-acceptor systems have lately attracted attention, owing to their exceptional energy-and electron-transfer properties. As a result, chemical derivatization of C59 N plays an important role in the realization of the aforementioned systems. The current Minireview aims to familiarize researchers with the main aspects of azafullerene synthesis, chemistry, and photophysical properties, while it mainly focuses on the synthetic methodologies employed for as well as on energy conversion schemes of azafullerene-based donor-acceptor systems.

Azafullerene (C59 N) was functionalized using a Mannich-type reaction and then subsequently condensed with lipoic acid to yield dithiolane-modified C59 N. In the following step, the extended dithiolane moiety from the C59 N core was utilized to decorate the azafullerene sphere with gold nanoparticles (Au NPs). The latter were initially stabilized with dodecanothiol (DT⋅Au) and then integrated on azafullerene through a ligand exchange reaction with the dithiolane-functionalized C59 N to produce the C59 N/DT⋅Au nanohybrid. The nanohybrid was fully characterized by spectroscopy and microscopy, revealing the formation of spherical nanoparticles with a diameter in the range of 2-5 nm, as imaged by HR-TEM. In the electronic absorption spectrum of C59 N/DT⋅Au nanohybrid, the characteristic surface plasmon band (SPB) of Au NPs was observed, however, it was redshifted compared with that of DT⋅Au. The redshift of the SPB is indicative of closer interparticle proximity of Au NPs, in accordance with the formation of aggregated NPs as observed by TEM, in C59 N/DT⋅Au nanohybrid. Excited-state interactions in C59 N/DT⋅Au were probed by photoluminescence assays. It was found that the weak emission of C59 N at 819 nm was blueshifted by 14 nm in C59 N/DT⋅Au, but was stronger in intensity, thus suggesting energy transfer to C59 N, within the organic-inorganic C59 N/DT⋅Au nanohybrid. Finally, with the aid of pump-probe measurements and transient absorption spectroscopy, the formation of the singlet excited state of C59 N was identified.

The supramolecular association via six complementary hydrogen bonds of an oligophenylenevinylene-based Hamilton receptor with a C60 derivative bearing a cyanurate unit was achieved. The association constant k ass for the superstructure assembled by the multiple hydrogen bonding of the Hamilton receptor and the cyanurate derivative was determined by 1H NMR and photoluminescence titration studies. The strength of k ass was calculated around 105 M−1 in toluene, while the stoichiometry of the corresponding complex was examined by Job's plot analysis of the absorption spectra changes and found 1:1.

The synthesis of a donor–acceptor silicon phthalocyanine (SiPc)-azafullerene (C59N) dyad 1 and of the first acceptor–donor–acceptor C59N-SiPc-C59N dumbbell triad 2 was accomplished. The two C59N-based materials were comprehensively characterized with the aid of NMR spectroscopy, MALDI-MS as well as DFT calculations and their redox and photophysical properties were evaluated with CV and steady-state and time-resolved absorption and photoluminescence spectroscopy measurements. Notably, femtosecond transient absorption spectroscopy assays revealed that both dyad 1 and triad 2 undergo, after selective photoexcitation of the SiPc moiety, photoinduced electron transfer from the singlet excited state of the SiPc moiety to the azafullerene counterpart to produce the charge-separated state, with lifetimes of 660 ps, in the case of dyad 1, and 810 ps, in the case of triad 2. The current results are expected to have significant implications en route to the design of advanced C59N-based donor–acceptor systems targeting energy conversion applications.

The tether-directed regioselective synthesis of equatorial bis-adducts of [60]fullerene via the 1,3-dipolar cycloaddition reaction of azomethine ylides is reported. A mono-[60]fulleropyrrolidine adduct, derived via 1,3-dipolar cycloaddition of azomethine ylides generated in situ upon thermal condensation of triphenylamine bis-aldehyde and an α-amino acid, was isolated and further reacted to yield, exclusively and selectively, the equatorial bis-adduct, which is structurally characterized by appropriate spectroscopic means.

The seven-step synthesis of a novel structural isomer of VPA-985, N-[3-chloro-4-(5H-pyrrolo[1,2-c][1.3] benzodiazepin-6(11H)-ylcarbonyl)phenyl]-5-fluoro-2-methylbenzamide, is described. (2-Aminophenyl)(1H-pyrrol-2-yl)methanone was converted with thiophosgene into (2-isothiocyanatophenyl)(1H-pyrrol-2-yl) methanone which was cyclised in the presence of base to 5-thioxo-5,6-dihydro-11H-pyrrolo[1,2-c][1.3]benzodiazepin-11-one. The latter underwent desulfurisation with Raney nickel followed by reduction with lithium aluminium hydride in the presence of aluminium trichloride and the resulting 6,11-dihydro-5H-pyrrolo[1,2-c][13]-benzodiazepine acylated with 2-chloro-4-nitrobenzoyl chloride to afford 6-(2-chloro-4-nitrobenzoyl)-6,11-dihydro-5H-pyrrolo[1,2-c][1.3]benzodiazepine. The nitro group in the latter compound was reduced with zinc and ammonium chloride to give the corresponding aniline derivative which was then acylated with 2-methyl-5-fluorobenzoyl chloride to provide the final product. (C) 2011 Elsevier Ltd. All rights reserved. Tetrahedron

We have designed and synthesized several structural isomers of anthramycin (heterocycles 2, 3, 5, 6, and 8) and found that, in particular, pyrrolobenzodiazepine 8 induces DNA cleavage and formation of small fragments of DNA. The cytotoxic effects of 8 were manifested with both non-transformed primary neuronal/glial cells and transformed Jurkat cells. The other compounds did not change the viability either of transformed or of non-transformed cells, and induced DNA cleavage to a lesser extent. (c) 2005 Elsevier Ltd. All rights reserved. Bioorganic and Medicinal Chemistry Letters

An efficient method for the synthesis of hitherto unknown alkyl(or aryl)pyrrolo[1,2- a ]quinoxalin-4(5 H )-ones 8a – g , 16 and 17 has been established. The method is based on the synthesis of the corresponding N -alkyl(or aryl)-1-(2-nitrophenyl)-1 H -pyrrole-2-carboxamides 3a – c and 7a – c , e which undergo denitrocyclisation with NaH in DMF in 4.5 or 2 h. When 3a was treated with NaH in DMF for 30 min the product of a Smiles rearrangement, 9 , was isolated. Under similar conditions but for 4.5 h 9 was converted into 8a . This confirms the involvement of a Smiles rearrangement during the denitrocyclisation process. Conversion of 3b into isomeric pyrroloquinoxalinones 12 and 13 confirms a process involving two pathways, direct denitrocylisation of 3b and Smiles rearrangement of 3b followed by denitrocylisation, respectively. Furthermore, denitrocylisation of 7d into pyrroloquinoxalinones 16 and 17 suggests that similar cyclisation pathways are followed by N -arylcarboxamides.

Microwaves have proven to be a powerful ally in any synthetic effort, shortening reaction times considerably and in some cases facilitating the reaction by offering higher yields or fewer byproducts. Since the mid '90s microwave-assisted synthesis has found its way into carbon nanostructures, offering significant advantages towards their functionalization. In this review, an overview of the lat- est trends in microwave-assisted functionalization of carbon nanostructured materials is presented covering major breakthroughs achieved in the last years for this novel, intriguing and non-conventional synthetic approach.