605-44-7Relevant academic research and scientific papers
On-Surface Synthesis and Collective Spin Excitations of a Triangulene-Based Nanostar
Castro, Silvia,Corso, Martina,Frederiksen, Thomas,Friedrich, Niklas,Hieulle, Jeremy,Lara, Francisco Romero,Pascual, Jose Ignacio,Pe?a, Diego,Rey, Dulce,Sanz, Sofía,Vegliante, Alessio
, p. 25224 - 25229 (2021/10/19)
Triangulene nanographenes are open-shell molecules with predicted high spin state due to the frustration of their conjugated network. Their long-sought synthesis became recently possible over a metal surface. Here, we present a macrocycle formed by six [3]triangulenes, which was obtained by combining the solution synthesis of a dimethylphenyl-anthracene cyclic hexamer and the on-surface cyclodehydrogenation of this precursor over a gold substrate. The resulting triangulene nanostar exhibits a collective spin state generated by the interaction of its 12 unpaired π-electrons along the conjugated lattice, corresponding to the antiferromagnetic ordering of six S=1 sites (one per triangulene unit). Inelastic electron tunneling spectroscopy resolved three spin excitations connecting the singlet ground state with triplet states. The nanostar behaves close to predictions from the Heisenberg model of an S=1 spin ring, representing a unique system to test collective spin modes in cyclic systems.
Near-infrared carbon rhodamine fluorescent dye and synthetic method thereof
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, (2018/12/14)
The invention relates to near-infrared carbon rhodamine fluorescent dye and a synthetic method thereof, which belongs to the technical field of fluorescent dye, and can solve the problems that the existing carbon rhodamine is high in synthetic difficulty. The preparation method of the dye comprises the following steps: performing nitrification reaction, reduction reaction and amino alkylation reaction for anthrone which is used as a raw material to obtain a midbody, and then enabling the midbody to successively react with a Grignard reagent and aryl lithium reagent to obtain a target product rhodamine fluorescent dye. The synthetic method adopted by the invention has the advantages of simple route, cheap raw material, high yield, and ease for separating and purifying the product. The prepared carbon rhodamine fluorescent dye has the characteristics of high molar extinction coefficient, good solubility, long fluorescent emission wavelength disposed in a near-infrared area and high fluorescent quantum yield and the like and can be used for research in the fields of fluorescent probes and fluorescent imaging.
Light-Induced Charge Separation in Densely Packed Donor-Acceptor Coordination Cages
Frank, Marina,Ahrens, Jennifer,Bejenke, Isabel,Krick, Marcel,Schwarzer, Dirk,Clever, Guido H.
, p. 8279 - 8287 (2016/07/16)
Photon-powered charge separation is achieved in a supramolecular architecture based on the dense packing of functional building blocks. Therefore, self-assembled dimers of interpenetrated coordination cages consisting of redoxactive chromophors were synthesized in a single assembly step starting from easily accessible ligands and Pd(II) cations. Two backbones consisting of electron rich phenothiazine (PTZ) and electron deficient anthraquinone (ANQ) were used to assemble either homo-octameric or mixed-ligand double cages. The electrochemical and spectroscopic properties of the pure cages, mixtures of donor and acceptor cages and the mixed-ligand cages were compared by steady-state UV-vis and transient absorption spectroscopy, supported by cyclic voltammetry and spectroelectrochemistry. Only the mixed-ligand cages, allowing close intra-assembly communication between the donors and acceptors, showed the evolution of characteristic PTZ radical cation and ANQ radical anion features upon excitation in the transient spectra. In contrast, excitation of the mixtures of the homo-octameric donor and acceptor cages in solution did not lead to any signs of electron transfer. Densely packed photo- and redox-functional self-assemblies promise molecular-level control over the morphology of the charge separation layer in future photovoltaic applications.
Synthesis, characterization and photovoltaic behavior of platinum acetylide polymers with electron-deficient 9,10-anthraquinone moiety
Li, Li,Chow, Wing-Cheong,Wong, Wai-Yeung,Chui, Chung-Hin,Wong, Raymond Siu-Ming
, p. 1189 - 1197 (2011/04/22)
A new class of soluble, solution-processable platinum(II) acetylide polymers functionalized with electron-deficient 9,10-anthraquinone spacer and their corresponding diplatinum model complexes were synthesized and characterized. The organometallic polymers exhibit good thermal stability and show low-energy broad absorption bands in the visible region. The effect of the presence of thiophene rings along the polymer chain on the optical and photovoltaic properties of these metallated materials was examined. The low-bandgap polymer with thiophene-anthraquinone-thiophene (donor-acceptor- donor) fragment can serve as a good electron donor for fabricating bulk heterojunction polymer solar cells by blending with a methanofullerene electron acceptor. At the same donor:acceptor blend ratio of 1:4, the light-harvesting ability and solar cell efficiency notably increase when the anthraquinone ring is sandwiched by two thiophene units. Photoexcitation of such polymer solar cells results in a photoinduced electron transfer from the π-conjugated metallopolymer to [6,6]-phenyl C61-butyric acid methyl ester with power conversion efficiency up to ~ 0.35%. For safety concern, these metallopolymers were also tested for possible cytotoxicity and they do not show significant cytotoxic activity on human liver derived cells and skin keratinocytes at reasonable doses, rendering these functional materials safe to use in practical devices.
SYNTHESIS, TELOMERASE INHIBITION AND CYTOTOXIC STUDIES ON 2,7-DISUBSTITUTED ANTHRAQUINONE DERIVATIVES
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Page/Page column 4, (2009/10/17)
An series of 2,7-disubstituted anthraquinone derivatives including a formula I are provided. R is a first substituted group selected from a group consisting of a hydrogen, an amino group, a nitro group, a hydroxyl group, a C1-C12 alkyl group, a C1-C12 alkyl halide group (—(CH2)nX), a C3-C12 cycloalkyl group, a benzyl group, a C1-C12 alkylamino group, a C5-C12 nitrocycloalkyl group and a heterocyclic group, n satisfies 1≦n≦12 and X is an atom selected from a group consisting of a fluoride (F), a chloride (Cl), a bromide (Br) and an iodine (I). The preparation method of the 2,7-disubstituted anthraquinone derivatives includes the steps of acetylating 2,7-diaminoanthraquinone to be one 2,7-disubstituted anthraquinone derivative, which can be further aminated to be another 2,7-disubstituted anthraquinone derivative.
Amide bond direction modulates G-quadruplex recognition and telomerase inhibition by 2,6 and 2,7 bis-substituted anthracenedione derivatives
Zagotto, Giuseppe,Sissi, Claudia,Moro, Stefano,Dal Ben, Diego,Parkinson, Gary N.,Fox, Keith R.,Neidle, Stephen,Palumbo, Manlio
, p. 354 - 361 (2008/09/16)
G-quadruplex structures of DNA represent a potentially useful target for anticancer drugs. Stabilisation of this arrangement at the ends of chromosomes may inhibit the action of telomerase, an enzyme involved in immortalization of cancer cells. Appropriately substituted amido anthracenediones are effective G-quadruplex stabilizers, but no information is available as yet on the possible modulation of G-quadruplex recognition and telomerase inhibition produced by the direction of the amide bond. To understand the basis of amido anthracenedione selectivity, we have synthesized a number of derivatives bearing the -CO-NH- or -NH-CO- group linked to the planar anthraquinone (AQ) moiety at 2,6 and 2,7 positions. The various isomers were tested in terms of telomerase inhibition, determined by the TRAP assay, G-quadruplex stabilisation measured by the increase in melting temperature of the appropriately folded oligonucleotide using FRET, and conformational and G4 binding properties examined by molecular modelling techniques. In all cases, enzymatic inhibition and G-quadruplex stabilization were directly related, which strongly supports the proposed molecular mechanism of telomerase interference. Interestingly, the AQ-NH-CO- arrangement performs invariantly better than the AQ-CO-NH- arrangement, showing a clear preference among isomeric derivatives. Theoretical calculations suggest that the former amide arrangement is co-planar with the aromatic system, whereas the latter is tilted by about 30° when considering the most stable conformation. A more extended planar surface would allow more efficient stacking interactions with the quadruplex structure, hence more effective telomerase inhibition.
Synthesis, DNA affinity, and antiprotozoal activity of fused ring dicationic compounds and their prodrugs
Arafa, Reem K.,Brun, Reto,Wenzler, Tanja,Tanious, Farial A.,Wilson, W. David,Stephens, Chad E.,Boykin, David W.
, p. 5480 - 5488 (2007/10/03)
Dicationic guanidine, N-alkylguanidine, and reversed amidine derivatives of fused ring systems (9a-d, 12a-c, 13a, and 13b) have been synthesized from their corresponding bis-amines. DNA binding studies suggest that the diguanidines and the N-alkyl diguanidines fluorenes bind in the minor groove in a manner similar to that of the previously reported dicationic carbazole derivatives. The diguanidines and the N-alkyl diguanidines showed promising in vitro activity against both Trypanosoma brucei rhodesiense and Plasmodium falciparum. Promising in vivo biological results were obtained for the dicationic N-isopropylguanidino-9H-fluorene (12c), giving 4/4 cures of the treated animals in the STIB900 animal model for African trypanosomiasis. The N-methyl analogue (12a) showed high activity as well. In addition, with the goal of enhancing the oral bioavailability, two novel classes of potential guanidine prodrugs were prepared. The N-alkoxyguanidine derivatives (12d) and (12e) were not effective as prodrugs. In contrast, a number of the carbamates (11a,c-e) showed promising activity. The value of the carbamate prodrugs was clearly demonstrated by the results for (11c), which gave 4/4 cures on oral administration in the STIB900 mouse model.
Human telomerase inhibition by regioisomeric disubstituted amidoanthracene-9,10-diones
Perry, Philip J.,Reszka, Anthony P.,Wood, Alexis A.,Read, Martin A.,Gowan, Sharon M.,Dosanjh, Harvinder S.,Trent, John O.,Jenkins, Terence C.,Kelland, Lloyd R.,Neidle, Stephen
, p. 4873 - 4884 (2007/10/03)
Telomerase is an attractive target for the design of new anticancer drugs. We have previously described a series of 1,4- and 2,6-difunctionalized amidoanthracene-9,10-diones that inhibit human telomerase via stabilization of telomeric G-quadruplex structures. The present study details the preparation of three further, distinct series of regioisomeric difunctionalized amidoanthracene-9,10-diones substituted at the 1,5-, 1,8-, and 2,7-positions, respectively. Their in vitro cytotoxicity and Taq DNA polymerase and human telomerase inhibition properties are reported and compared with those of their 1,4- and 2,6-isomers. Potent telomerase inhibition ((tel)IC50 values 1.3-17.3 μM) is exhibited within each isomeric series. In addition, biophysical and molecular modeling studies have been conducted to examine binding to the target G-quadruplex structure formed by the folding of telomeric DNA. These studies indicate that the isomeric diamidoanthracene-9,10-diones bind to the human telomeric G-quadruplex structure with a stoichiometry of 1:1. Plausible G-quadruplex-ligand complexes have been identified for each isomeric family, with three distinct modes of intercalative binding being proposed. The exact mode of intercalative binding is dictated by the positional placement of substituent side chains. Furthermore, in contrast to previous studies directed toward triplex DNA, it is evident that stringent control over positional attachment of substituents is not a necessity for effective telomerase inhibition.
