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1.
Chemistry ; 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35916326

RESUMO

Tetraiodotetraazapentacene I 4 TAP , the last missing derivative in the series of halogenated silylated tetraazapentacenes, was synthesized via condensation chemistry from a TIPS-ethynylated diaminobenzothiadiazol in three steps. Single and double reduction furnished its air-stable monoanion and relatively air-stable dianion, both of which were characterized by crystallography. All three species are structurally and spectroscopically compared to non-halogenated TAP and Br 4 TAP. I 4 TAP is an n-channel material in thin-film transistors with average electron mobilities exceeding 1 cm 2 (Vs) -1 .

2.
Chemistry ; 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-35947374

RESUMO

Four N-acenoacenes were synthesized and analyzed for their optoelectronic properties and solid-state packings. Two of the regioisomeric acridinoacridines are TIPS-ethynylated, whereas the other pair are Boc- and triflate substituted derivatives. The two TIPS-ethynyldiazaacenoacenes were processed into organic thin-film transistors with saturation hole mobilities reaching 2.9x10-2cm2 (Vs) -1 .

3.
Adv Sci (Weinh) ; : e2202710, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35896771

RESUMO

Buchwald-Hartwig coupling of a triisopropylsilyl (TIPS)-ethynylated dibromo-N,N'-dihydrotetraazapentacene with 1,4-bis(TIPS-ethynyl)-2,3-diaminonaphthalene furnishes a dihydrohexaazaoctacene. Its oxidation with MnO2 results in a 7,7'-bi(hexaazaoctacenyl). In addition to eight TIPS-ethynyl groups, the bioctacene motif protects the azaoctacene subunits. The biazaoctacenyl displays a τ1/2 of > 5 d in dilute solution under ambient conditions. In the crystalline state it is persistent for > 10 months.

4.
Artigo em Inglês | MEDLINE | ID: mdl-35900162

RESUMO

We describe a new type of nitrogen-centered polycyclic scaffold comprising a unique combination of 5-, 6-, and 7-membered rings. The compound is accessible through an intramolecular oxidative cyclodehydrogenation of tri(1-naphthyl)amine. To the best of our knowledge this is the very first example of a direct 3-fold cyclization of a triarylamine under oxidative conditions. The unusual ring fusion motif is confirmed by X-ray crystallography and the impact of cyclization on the electronic and photophysical properties is investigated both experimentally and theoretically based on density-functional theory (DFT) calculations. The formation of the unexpected product is rationalized by detailed mechanistic studies on the DFT level. The results suggest the cyclization to occur under kinetic control via a dicationic mechanism.

5.
Chemistry ; : e202201554, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35652474

RESUMO

We disclose a successive π-expansion of pyracylene towards boat-shaped polycyclic scaffolds. The unique structural features of the resulting compounds were revealed by X-ray crystallographic analysis. Depending on the extent of π-expansion the compounds display intense bathochromically shifted absorption bands in their UV/Vis spectra and are prone to several redox events as documented by cyclic voltammetry. The experimental observations are in line with the computational studies based on density functional theory, suggesting progressive narrowing of the HOMO-LUMO gap and distinct evolution of the electronic structure and aromaticity.

6.
J Org Chem ; 87(12): 7778-7785, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35668356

RESUMO

The synthesis of pyrrolidin-5-one-2-carboxamides 6a-p has been developed via a one-pot Ugi reaction of allenic acids, primary amines, isocyanides, and aldehydes followed by regioselective cyclization of the resultant N-substituted-2-allenamides with KOt-Bu at room temperature. The cyclization reaction was carried out through a 5-exo-dig approach, which resulted in good yields and high atom-economy under transition-metal-free and mild reaction conditions.

7.
Org Lett ; 24(24): 4349-4353, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35699937

RESUMO

α-Ketoamides have been found to be an important functional group in a broad spectrum of inhibitors such as the Corona virus and other viruses. Here we report an unprecedented gold-catalyzed 2-fold reaction of a bromoalkyne with anthranils. Hydrolysis of the initial product then directly leads to α-ketoamides. Water addition to the intermediate α-iminoimidoyl halides delivered α-ketoamides from a broad range of bromoalkynes.


Assuntos
Ouro , Metano , Catálise , Metano/análogos & derivados
8.
Adv Mater ; 34(31): e2202290, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35657163

RESUMO

Anthropogenic greenhouse gases contribute to global warming. Among those gases, perfluorocarbons (PFCs) are thousands to tens of thousands of times more harmful to the environment than comparable amounts of carbon dioxide. To date, materials that selectively adsorb perfluorocarbons in favor of other less harmful gases have not been reported. Here, a series of porous organic cage compounds with alkyl-, fluoroalkyl-, and partially fluorinated alkyl groups is presented. Their isomorphic crystalline states allow the study of the structure-property relationship between the degree of fluorination of the alkyl chains and the gas sorption properties for PFCs and their selective uptakes in comparison to other, nonfluorinated gases. By this approach, one compound having superior selectivities of PFCs versus N2 or CO2 under ambient conditions is identified.

9.
Chemistry ; : e202201816, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35699266

RESUMO

New N-heterocyclic compounds for organic functional materials and their efficient syntheses are highly demanded. A surprising entropy-induced selectivity switch in the gold-catalyzed intramolecular hydroarylation of 2-ethynyl N-aryl indoles was found and its exploitation led to straightforward syntheses of indolo[1,2-a]quinolines. Experimental and computational mechanistic investigations gave insight into this uncommon selectivity phenomenon and into the special reactivity of the indolo[1,2-a]quinolines. The high functional group tolerance of this methodology enabled access to a diverse scope with high yields. In addition, bidirectional approaches, post-functionalization reactions, and π-extension of the core structure were feasible. An in-depth study of the photophysical properties explored the structure-effect relationship for different derivatives and revealed a high potential of these compounds for future applications as functional materials.

10.
Chemistry ; : e202201527, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35699158

RESUMO

The pollution of groundwater with nitrate is a serious issue because nitrate can cause several diseases such as methemoglobinemia or cancer. Therefore, selective removal of nitrate by efficient binding to supramolecular hosts is highly desired. Here we describe how to make [2+3] amide cages in very high to quantitative yields by applying an optimized Pinnick oxidation protocol for the conversion of corresponding imine cages. By NMR titration experiments of the eight different [2+3] amide cages with nitrate, chloride and hydrogen sulfate we identified one cage with an unprecedented high selectivity towards nitrate binding vs. chloride (S=705) or hydrogensulfate (S>13500) in CD2 Cl2 /CD3 CN (1 : 3). NMR experiments as well as single-crystal structure comparison of host-guest complexes give insight into structure-property-relationships.

11.
Chemistry ; 28(34): e202201362, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35616165

RESUMO

Invited for the cover of this issue are the groups of Christel Herold-Mende and Carlos Romero-Nieto at the Universities of Heidelberg and Castilla-La Mancha. The image depicts the use of phosphaphenalene gold(I) complexes for the treatment of brain cancer. Read the full text of the article at 10.1002/chem.202104535.


Assuntos
Ouro , Pirróis
12.
J Am Chem Soc ; 144(22): 9883-9892, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35635258

RESUMO

Among graphene nanoribbons (GNRs), reports on coronene-based GNRs were very rare, despite the unique optoelectronic properties of coronene. Herein, the synthesis of a series of structurally precise and soluble thieno-fused coronene nanoribbons (CR-1 to CR-4) with up to four coronene units connected through benzene rings along their K-regions is described by two different synthetic approaches. Due to the triptycene end-caps, all CRs are soluble, allowing the characterization of such structures in solution and the study of the length-dependent photophysical properties that are supported by theoretical calculations.

13.
J Am Chem Soc ; 144(18): 8306-8316, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35471963

RESUMO

New N-heterocyclic fluorophores are sought-after compounds for organic electronic devices. Here, we report on a straightforward synthesis to access meta/para-dipyrrolobenzenes and para-dipyrrolopyrazines in high yields using a bidirectional gold-catalyzed cyclization strategy. The versatility of our reaction protocol was showcased by preparing dipyrroloarenes with different substituents, various functional groups, and in a multitude of substitution patterns. Furthermore, we showed that the dipyrroloarenes can be post-modified by N-alkylation to improve the solubility or bromination to yield precursors for further derivatization via cross-coupling. Investigation of the photophysical properties of the─mostly unprecedented─dipyrroloarenes identified strong blue emitters such as the diphenyl meta-dipyrrolobenzene with a quantum yield of 98%. Moreover, we showed that changes in the solvent polarity or interactions with Lewis acids such as borane can be used to fine-tune the photophysical properties of the fluorophores.


Assuntos
Corantes Fluorescentes , Ouro , Alquilação , Catálise , Ciclização
14.
Angew Chem Int Ed Engl ; 61(26): e202200918, 2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35377538

RESUMO

Sixfold TIPS-ethynylation combined with fourfold bromination of the armchair edges furnishes a long-lived, soluble heptacene; π-extension via Stille coupling accesses a persistent tetrabenzononacene. Both types of acenes were stabilized best by double TIPS-ethynylation on every other benzene ring. Tetrabromoheptacene is an ambipolar transistor material (up to 0.036 cm2 V-1 s-1 n-channel), which was corroborated by generation of its monoanion and monocation.

15.
Angew Chem Int Ed Engl ; 61(30): e202204123, 2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35474405

RESUMO

We describe the on-surface dehalogenative homocoupling of benzylic bromides, namely bis-bromomethyl- and bis-gem-(dibromomethyl) naphthalene as a potential route to either hydrocarbon dimers or conjugated polymers on Au(111). While bis-gem-(dibromomethyl) naphthalene affords different dimers with naphthocyclobutadiene as the key intermediate, bis-bromomethyl naphthalene furnishes a poly(o-naphthylene vinylidene) as a non-conjugated polymer which undergoes dehydrogenation toward its conjugated derivative poly(o-naphthylene vinylene) upon mild annealing. A combination of scanning tunneling microscopy, non-contact atomic force microscopy and density functional theory calculations provides deep insights into the prevailing mechanisms.

16.
Org Biomol Chem ; 20(15): 3076-3080, 2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35352735

RESUMO

We have developed a new three-component approach using ortho-alkynylbenzaldoximes involving the formation of a cyclic nitrone in the presence of Br2 or ICl for the synthesis of 1-aminoisoquinolines via cascade 6-endo-cyclization, 1,3-dipolar cycloaddition reaction with 2H-azirines, and ring-opening reaction sequences. The broad range of structurally diverse products, good to high yields, high atom-economy and high bond-formation efficiency make this method an attractive alternative for the synthesis of 1-aminoisoquinolines.


Assuntos
Azirinas , Ciclização , Reação de Cicloadição
17.
Chemistry ; 28(34): e202104535, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35293640

RESUMO

Brain cancer, one of the most lethal diseases, urgently requires the discovery of novel theranostic agents. In this context, molecules based on six-membered phosphorus heterocycles - phosphaphenalenes - are especially attractive; they possess unique characteristics that allow precise chemical engineering. Herein, we demonstrate that subtle structural modifications of the phosphaphenalene-based gold(I) complexes lead to modify their electronic distribution, endow them with marked photophysical properties and enhance their efficacy against cancer. In particular, phosphaphenalene-based gold(I) complexes containing a pyrrole ring show antiproliferative properties in 14 cell lines including glioblastomas, brain metastases, meningiomas, IDH-mutant gliomas and head and neck cancers, reaching IC50 values as low as 0.73 µM. The bioactivity of this new family of drugs in combination with their photophysical properties thus offer new research possibilities for both the fundamental investigation and treatment of brain cancer.


Assuntos
Antineoplásicos , Neoplasias Encefálicas , Glioblastoma , Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias Encefálicas/patologia , Glioblastoma/tratamento farmacológico , Ouro/química , Humanos , Luminescência , Pirróis/farmacologia
18.
Chemistry ; 28(34): e202200326, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35293646

RESUMO

A family of fully bridged triphenylamines with embedded 5- and 7-membered rings is presented. The compounds are potent electron donors capable to undergo donor/acceptor interactions with strong cyano-based acceptors both in the solid state and solution. These interactions were evaluated by IR and UV/vis spectroscopy as well as X-ray crystallography. The vinylene-bridged compound was oxidized to the corresponding 1,2-diketone which readily underwent acid-catalyzed condensation with selected 1,2-phenylenediamines. The resulting π-extended quinoxaline derivatives represent valuable building blocks for the development of functional chromophores upon appropriate functionalization.

19.
Nat Commun ; 13(1): 1672, 2022 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-35354823

RESUMO

Pt(II) and Au(III)-mediated intermolecular divergent annulations of benzofurazans and ynamides highlighted the N- to O-selectivity of tunable metal carbene intermediates. PtCl2 with a bulky phosphite ligand resulted in the specific synthesis of six-membered quinoxaline N-oxides and successfully suppressed the in-situ deoxygenation of N-oxides. On the other hand, an unique gold(III) catalyst (2,6-di-MeO-PyrAuCl3) led to the five-membered ring products, benzimidazoles. A broad scope of functional groups was well compatible, delivering better yields and selectivities in contrast to conventional gold(I) catalysts. The different behavior of presumed platinum(II) and gold(III) carbenes with respect to chemoselectivity was intensively examined by experiments and DFT calculations. A detailed mechanistic study, based on DFT calculations, revealed that the highly electrophilic carbocation-like gold(III) carbene triggers an oxophilic cyclization, followed by a cascade ring contraction and acyl migration. On the contrary, the Pt carbene species is less cationic, favoring the formation of the six-membered ring via N-attack.


Assuntos
Ouro , Platina , Ciclização , Metano/análogos & derivados
20.
Inorg Chem ; 61(8): 3508-3515, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35179353

RESUMO

We present a protocol to synthesize air stable gem-diaurated gold(III) compounds from 1,3-diketones in a single cycloauration step with tetrachloroauric acid. So far related species were only accessible from phosphonium bis(ylide) ligands which hold the two gold atoms in close proximity. Lacking such a constraint, our compounds show the longest Au-Au distances of all gem-diaurated carbons, ranging from 3.26 to 3.32 Å. Modeling based on results of CCSD(T) calculations shows no stabilization by aurophilic interactions for our gold(III) systems, compared to 9.1 kcal/mol for gold(I) gem-diauration. This demonstrates no aurophilic interactions are needed for the isolation of air stable gem-diaurated gold(III) complexes. We show the new gem-diaurated gold(III) compounds are active in the gold-catalyzed phenol synthesis and highly active in the cycloisomerization of an N-propargylcarboxamide; here, we obtained the so far highest known TON of over 2500 per gold atom with respect to the oxazole formation.

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