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1.
J Am Chem Soc ; 143(9): 3306-3311, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33636078

RESUMO

Octaaryl-substituted bisquinodimethanes (BQDs) with a zigzag structure were designed as redox-switchable molecules that undergo four-electron oxidation to produce tetracationic pentacenes with a doubly twisted structure. In contrast to one-stage four-electron oxidation of BQDs, stepwise two-electron reduction of tetracationic pentacenes occurs to give dicationic anthracenes and then the original BQDs, step-by-step. Since both tetracations and dications exhibit near-infrared (NIR) absorptions (-1400 nm) based on an intramolecular charge-transfer interaction, changes in not only their structures but also their UV-vis-NIR spectra can be controlled by redox stimuli. In this Communication, we present an unprecedented one-step π-extension to pentacene from non-fused benzene rings by oxidation, and subsequent two-stage deannulation to benzene rings via anthracene upon reduction. All structures were determined by single-crystal X-ray analyses, and their properties were characterized by spectroscopic and theoretical studies.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33576120

RESUMO

Cyclo-dehydrogenation is of importance to induce the planarization of molecules on noble surfaces upon annealing. In contrast to a number of successful syntheses of polycyclic aromatic hydrocarbons by forming carbon-carbon bonds, it is still rare to conduct conjugation and cleavage of carbon-nitrogen bonds in molecules. Here, we present a systematic transformation of the C-N bonds in11,11,12,12-tetraphenyl-1,4,5,8-tetraazaanthraquinodimethane as well as three other derivatives on Au(111). With bond-resolved scanning tunneling microscopy, we discovered novel the "heterocyclic segregation" reaction of one pyrazine ring with two nitrogen atoms to form two quinoline rings with one nitrogen each. Density functional theory calculations showed that the intramolecular ring-forming and -opening of N-heterocycles are strongly affected by the initial hydrogen-substrate interaction.

3.
Chem Commun (Camb) ; 57(9): 1157-1160, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33411863

RESUMO

Redox-active hexakis(4-carboxyphenyl) tri(dithiolylidene)cyclohexanetrione (CPDC) was synthesized. The CPDC-based porous framework, constructed via anomalistic helical hydrogen-bonding, exhibites permanent porosity and photoconductivity.

4.
Angew Chem Int Ed Engl ; 59(49): 22252-22257, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830906

RESUMO

Since carbon-carbon (C-C) covalent bonds are rigid and robust, the bond length is, in general, nearly constant and depends only on the bond order and hybrid orbitals. We report herein direct visualization of the reversible expansion and contraction of a C(sp3 )-C(sp3 ) single bond by light and heat. This flexibility of a C-C bond was demonstrated by X-ray analysis and Raman spectroscopy of hexaphenylethane (HPE)-type hydrocarbons with two spiro-dibenzocycloheptatriene units, the intramolecular [2+2] photocyclization of which and thermal cleavage of the resulting cyclobutane ring both occur in a single-crystalline phase. The force constant of the contracted C-C bond is 1.6 times greater than that of the expanded bond. Since formation of the cyclobutane ring and contraction of the C-C bond lower the HOMO level by approximately 1 eV, the oxidative properties of these HPEs with a flexible C-C bond can be deactivated/activated by light/heat.

5.
Chem Asian J ; 15(7): 1147-1155, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32030909

RESUMO

When the 1,1,4,4-tetraanilinobutadiene skeleton is attached with two halogenated aryl units at the 2,3-positions, they undergo facile two-electron oxidation to give stable dicationic dyes which exhibit a near-infrared (NIR) absorption whereas the neutral dienes show only pale color. Therefore, a distinct electrochromic response with an absorption change in the NIR region is achieved, which is attracting considerable recent attention from the viewpoint of bioimaging. Herein, we demonstrate that the redox potentials of the 1,1,4,4-tetraanilinobutadiene can be precisely controlled by the donating properties of the amino group on the aniline unit as well as the number of halogen atoms on the aryl units at 2,3-positions on the butadiene. In contrast, the NIR absorption bands mainly depend on the number of halogen atoms irrespective to the donating properties of aniline unit. Thus, the hexaarylbutadiene skeleton is proven to be a versatile scaffold to develop less-explored organic NIR electrochromic materials, whose redox and spectroscopic properties can be finely tuned by modifying/attaching the proper substituents.

6.
Nat Commun ; 11(1): 446, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974383

RESUMO

Afterglow luminescent probes with high signal-to-background ratio show promise for in vivo imaging; however, such probes that can be selectively delivered into target sites and switch on afterglow luminescence remain limited. We optimize an organic electrochromic material and integrate it into near-infrared (NIR) photosensitizer (silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) and (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) containing nanoparticles, developing an H2S-activatable NIR afterglow probe (F12+-ANP). F12+-ANP displays a fast reaction rate (1563 ± 141 M-1 s-1) and large afterglow turn-on ratio (~122-fold) toward H2S, enabling high-sensitivity and -specificity measurement of H2S concentration in bloods from healthy persons, hepatic or colorectal cancer patients. We further construct a hepatic-tumor-targeting and H2S-activatable afterglow probe (F12+-ANP-Gal) for noninvasive, real-time imaging of tiny subcutaneous HepG2 tumors (<3 mm in diameter) and orthotopic liver tumors in mice. Strikingly, F12+-ANP-Gal accurately delineates tumor margins in excised hepatic cancer specimens, which may facilitate intraoperative guidance of hepatic cancer surgery.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Sulfeto de Hidrogênio/análise , Neoplasias Hepáticas/diagnóstico por imagem , Substâncias Luminescentes/química , Imagem Molecular/métodos , Animais , Neoplasias Colorretais/sangue , Cistationina beta-Sintase/análise , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/análise , Cistationina gama-Liase/metabolismo , Células Hep G2 , Humanos , Sulfeto de Hidrogênio/sangue , Sulfeto de Hidrogênio/química , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas Experimentais/diagnóstico por imagem , Substâncias Luminescentes/síntese química , Camundongos Endogâmicos BALB C , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Polímeros/química , Compostos de Vinila/química , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Angew Chem Int Ed Engl ; 59(16): 6581-6584, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-31930668

RESUMO

Thermally switchable redox properties have been reported to be due to a change in the spin state of newly designed overcrowded ethylenes, which can adopt closed-shell folded and open-shell twisted forms. In this study, tetrathienylanthraquinodimethane derivatives were designed to be in thermal equilibrium between a more stable folded form and less stable but more donating twisted diradical in solution, so that the oxidation potential can be controlled by heating/cooling. This is the first example of a switching of redox properties based on a thermally equilibrated twisted diradical, which can be more readily oxidized to the twisted dication.

8.
J Am Chem Soc ; 141(45): 18293-18300, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31630518

RESUMO

Highly strained hydrocarbons with two di/tribenzocycloheptatriene units were designed as electrochromic overcrowded ethylenes that undergo reversible interconversion with stable dicationic dyes. Due to severe steric repulsion, two configurational isomers (anti,anti-folded and syn,anti-folded forms) were isolated as stable entities. Photo- and thermal interconversion of these isomers proceeded cleanly: one-way photoisomerization occurred from anti,anti- to syn,anti-form and one-way thermal isomerization was observed from syn,anti- to anti,anti-form. Even though both isomers undergo two-electron oxidation into the same twisted dications, quite different oxidation potentials enable completely selective oxidation of syn,anti-isomers. Thus, the present multiconfigurational strained hydrocarbons are capable of switching of activation/deactivation of their electrochromic properties by light/heat.

9.
Chemistry ; 25(32): 7759-7765, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-30942496

RESUMO

A method to obtain an organic mixed-valence state with long-range delocalization is proposed, which enables the selective generation of half-filled (n/2-charged) polycations from linearly bridged oligomers with n electron-donating units. When π-extended phenylenediamine units are connected by meta-xylylene-type spacers, the resulting oligomers adopt non-folded structures in the neutral state owing to the non-conjugating and flexible nature of the spacer, whereas the structure shows a drastic change into a one-dimensional columnar stack upon oxidation to the corresponding half-filled polycations. Although they are nano-sized discrete molecules, they can mimic the electronic structure of crystalline organic conductors in a mixed-valence state. The key for the oligomer design is adoption of the best-matched spacer that facilitates formation of the singly charged pimer in the dichromophoric system whereas the corresponding doubly charged π-dimer is disfavored.

10.
Chempluschem ; 84(6): 634-642, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31944008

RESUMO

A perfluorobiphenyl-2,2'-diyl dication and its corresponding dihydrophenanthrene-type electron donor are interconvertible upon two-electron transfer. Redox-triggered C-C bond-formation/cleavage caused a drastic change in the torsion angle of the biphenyl unit. Thus, π-delocalization ON/OFF switching was observed as a change in the UV absorption upon electrolysis of the linearly extended analogue with two phenylethynyl groups. A further extended π-system with a molecular length of ca. 3.5 nm, which has two switching units, was synthesized. Spectroelectrograms as well as voltammetric analyses showed that the two units act nearly simultaneously because of the very small inter-unit electrostatic repulsion in the tetracationic state. Thus, the present pair is a promising candidate as a switching unit for "molecular wires" with controllable π-delocalization, in which a higher ON/OFF ratio of delocalization could be realized by incorporating multiple switching units.

11.
J Am Chem Soc ; 140(47): 16340-16352, 2018 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-30384600

RESUMO

Electrochromic materials (EMs) are widely used color-switchable materials, but their applications as stimuli-responsive biomaterials to monitor and control biological processes remain unexplored. This study reports the engineering of an organic π-electron structure-based EM (dicationic 1,1,4,4-tetraarylbutadiene, 12+) as a unique hydrogen sulfide (H2S)-responsive chromophore amenable to build H2S-activatable fluorescent probes (12+-semiconducting polymer nanoparticles, 12+-SNPs) for in vivo H2S detection. We demonstrate that EM 12+, with a strong absorption (500-850 nm), efficiently quenches the fluorescence (580, 700, or 830 nm) of different fluorophores within 12+-SNPs, while the selective conversion into colorless diene 2 via H2S-mediated two-electron reduction significantly recovers fluorescence, allowing for non-invasive imaging of hepatic and tumor H2S in mice in real time. Strikingly, EM 12+ is further applied to design a near-infrared photosensitizer with tumor-targeting and H2S-activatable ability for effective photodynamic therapy (PDT) of H2S-related tumors in mice. This study demonstrates promise for applying EMs to build activatable probes for molecular imaging of H2S and selective PDT of tumors, which may lead to the development of new EMs capable of detecting and regulating essential biological processes in vivo.


Assuntos
Compostos de Anilina/uso terapêutico , Corantes Fluorescentes/uso terapêutico , Sulfeto de Hidrogênio/análise , Fármacos Fotossensibilizantes/uso terapêutico , Estilbenos/uso terapêutico , Compostos de Anilina/síntese química , Compostos de Anilina/farmacologia , Compostos de Anilina/toxicidade , Animais , Linhagem Celular Tumoral , Desenho de Fármacos , Feminino , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Corantes Fluorescentes/toxicidade , Células HEK293 , Humanos , Sulfeto de Hidrogênio/química , Sulfeto de Hidrogênio/metabolismo , Raios Infravermelhos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Imagem Molecular/métodos , Nanopartículas/química , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/efeitos da radiação , Fármacos Fotossensibilizantes/toxicidade , Polímeros/química , Células RAW 264.7 , Oxigênio Singlete/metabolismo , Estilbenos/síntese química , Estilbenos/farmacologia , Estilbenos/toxicidade , Tiadiazóis/química , Compostos de Vinila/química , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Chem Commun (Camb) ; 54(73): 10300-10303, 2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30140806

RESUMO

The angle strain induced by ring annulation on a spiro-type naphthofuran weakens its C(sp3)-O bond at the opposite peri-position and endows expandability, so that quite different bond lengths [1.493(3)-1.526(6) Å] are determined for the elongated C(sp3)-O bond of the corresponding spiro-acenaphthofuran derivative upon X-ray analyses of its pseudopolymorphs.

13.
Molecules ; 22(11)2017 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-29113057

RESUMO

The title dispiro hydrocarbon 1 was designed as a new electrochromic material. This multiply clamped hexaphenylethane-type electron donor was prepared from 2,2'-diiodobiphenyl via biphenyl-2,2'-diylbis(dibenzotropylium) 22+ salt. X-ray analysis of 1 revealed a highly strained structure as reflected by an elongated "ethane" bond [bond length: 1.6665(17) Å] and nearly eclipsed conformation. The weakened bond was cleaved upon two-electron oxidation to regenerate the deeply colored dication 22+. The reversible interconversion between 1 and 22+ is accompanied not only by a drastic color change but also by C-C bond formation/cleavage. Thus, the voltammogram showed a pair of well-separated redox waves, which is characteristic of "dynamic redox (dyrex)" behavior. The tetrahydro derivative of 1 with two units of spiro(dibenzocycloheptadiene), which suffers from more severe steric congestion, was also prepared. The crystallographically determined bond length for the central C-C bond [1.705(4) Å] is greatest among the values reported for 9,9,10,10-tetraaryl-9,10-dihydrophenanthrene derivatives.


Assuntos
Modelos Moleculares , Fenantrenos/química , Compostos de Espiro/química
14.
Chempluschem ; 82(7): 1043-1047, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31961615

RESUMO

Biphenyl-2,2'-diylbis(10-methyl-9-methyleneacridan)-type electron donor 1, which has two tethered cyclic disulfide units at the 6,6'-positions, was designed and synthesized as the first member of a dynamic redox (dyrex) system that can form molecular layers on a Au(111) electrode. Upon the two-electron (2 e) oxidation of 1, the persistent dicationic dye 22+ was generated with the formation of a new C-C bond, which is reversibly cleaved upon 2 e reduction to regenerate 1 (dyrex behavior). Similar dyrex interconversion occurs in the molecular layer of 1 on gold. The chemical identities of 1/Au and electrochemically generated 22+ /Au were unambiguously determined by in situ IR spectroscopy in the attenuated total reflection mode. In situ scanning tunneling microscopy (STM) was conducted under electrochemical conditions to examine the surface structure of 1 adsorbed on a Au(111) electrode. Although no long-range-ordered morphology was found in the STM image of 1, an in situ STM study of the potential-induced dyrex reaction of 1 to 22+ showed that the grained spots in the image became slightly brighter.

15.
Org Lett ; 16(10): 2642-5, 2014 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-24796375

RESUMO

New acceptor-donor-acceptor (A-D-A) oligomers (1 and 2) containing a central dithieno[3,2-b:2',3'-d]pyrrole unit and end-capping thieno[2,3-c]pyrrole-4,6-dione groups have been synthesized and characterized. Bulk heterojunction solar cells were prepared together with PC61BM and PC71BM, and the best results were obtained for the latter acceptor using 1,8-diiodooctane as an additive. Photovoltaic devices containing these oligomers achieved high external quantum efficiencies up to 50%.

16.
Materials (Basel) ; 4(11): 1906-1926, 2011 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-28824114

RESUMO

A series of biphenyl-2,2'-diylbis(diarylmethanol)s 3, which have two kinds of aryl groups at the bay region, were efficiently obtained by integrated flow microreactor synthesis. The diols 3NO/NX are the precursors of unsymmetric biphenylic dications 2NO/NX2+, which are transformed into the corresponding dihydrophenanthrenes 1NO/NX via 2NO/NX+• upon reduction, when they exhibit two-stage color changes. On the other hand, the steady-state concentration of the intermediate 2NO/NX+• is negligible during the oxidation of 1NO/NX to 2NO/NX2+, which reflects unique tricolor electrochromicity with a hysteretic pattern of color change [color 1→color 2→color 3→color 1].

17.
Chem Commun (Camb) ; 46(23): 4100-2, 2010 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-20390155

RESUMO

The helical configuration of dication dyes 2(2+) with a dihydrodibenzoxepin unit remained unchanged even at high temperature, whereas the corresponding neutral electron donors 1 with a tetrahydrophenanthroxepin skeleton easily underwent racemization. Due to their electrochemical bistability, electron exchange between 1 and 2(2+) is prohibited. Thus, the above electrochromic pairs can serve as novel chiral-memory units where redox reactions trigger switching between an "erasable/writable"-state (1) and a "memorizing"-state (2(2+)).


Assuntos
Dibenzoxepinas/química , Elétrons , Modelos Moleculares , Oxirredução
18.
Chemistry ; 15(37): 9434-41, 2009 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-19621397

RESUMO

3,3,4,4-Tetaaryldihydro[5]helicenes (1) and 1,1'-binaphthyl-2,2'-diylbis(diarylcarbenium)s (2(2+)) can be reversibly interconverted upon electron transfer, which is accompanied by a vivid color change (electrochromism) as well as by the formation/cleavage of a C-C bond ("dynamic redox behavior"). Because only the neutral donor 1 exhibits strong fluorescence, electrochemical input can further modify the fluorescent properties of the pair. Due to the configurational stability of the helicity in 1 and axial chirality in 2(2+), the redox reaction of optically pure material proceeds stereospecifically, which induces a chiroptical change such as circular dichroism (CD) as an additional output. The CD spectra of dications 2(2+) exhibit solvent dependency (chiro-solvatochromism), which is accompanied by solvatochromic behavior based on the pi-pi interaction of the two cationic chromophores as well as coordinative interaction of the Lewis basic solvent to the Lewis acidic triarylcarbenium moieties. Thus, the present system is endowed with multi-input functionality for modifying multiple output signals.

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