Synthesis of Long-Chain SpirobenzopyransBearing a Monoazacrown ether

Two new long-chain spirobenzopyrans and their crowned derivatives were designed and synthesized.

A CONVENIENT SYNTHESIS OF NEW HYDROXYL CYCLIC AZA COMPOUNDS

A convenient synthetic route to a series of hydroxyl cyclic di- and tri-aza compounds was described. Condensation of 1, 3-dichloropropanol[2] with the appropriate disodium salts of N-tosylated di-and triamine in EtOH gave the corresponding 7-, 8- and 10-membered di- and triamine cycles in reasonable yields. The tosyl groups were removed with 33%HBr-HOAc in ca.90% yields.

Synthesis of Spirobenzopyrans Carrying a Monoaza-benzo-15-C-5 at the 8-position

Synthesis of spirobenzopyrans bearing monoazacrown at the 8-position is described.

Rational Design and Application of an Indolium-Derived Heptamethine Cyanine with Record-Long Second Near-Infrared Emission

Heptamethine cyanine dyes,typified by indocyanine green,have been extensively employed as bioimaging indicators and theranostic agents.Significant efforts have been made to develop functional heptamethine cyanine dyes with outstanding bioimaging and theranostic utilities.In this work,we rationally designed and successfully developed a novel indolium-like heptamethine cyanine dye by installing indolium-derived polycyclic aromatic hydrocarbons on the terminal ends of a conjugated polyene backbone.This dye showed excellent photostability and showed bright fluorescent emission in the second near-infrared(NIR-Ⅱ)window with a peak at approximately 1120 nm.Such long wavelength emission prompted a superior bioimaging resolution in vivo.In particular,this NIR-Ⅱ dye had the remarkable capability of marking the blood vessels of the hindlimbs,abdomens,and brains of mice.More significantly,this dye involved a typical indolium-like heptamethine skeleton and exhibited two strong absorption bands in the 700–1300 nm NIR range,which endowed it with an intrinsic tumor-targeting capability and a high photothermal conversion efficiency(up to 68.2%),serving for the photothermal therapy of tumors under the guidance of NIR-Ⅱ fluorescence imaging.This work provides an efficient design strategy for achieving indolium-like heptamethine cyanine dyes with further NIR-Ⅱ emission.

Synergistic effects of multiple rotors and hydrogen-bond interactions lead to sensitive near-infrared viscosity probes for live-cell microscopy

Changes in cellular viscosity are associated with various physiological processes and pathological conditions.To study these cellular processes and functions,highly sensitive fluorescent probes that detect subtle changes in viscosity are urgently needed but remain lacking.In this study,we present a series of viscosity-responsive near-infrared(NIR)fluorescent probes based on styrene-coated boron dipyrromethene(BODIPY).The probe modified with dimethylaminostyrene and piperazine at the two terminals of the BODIPY scaffold showed extremely high viscosity sensitivity values(x,around 1.54),with excellent performance for detecting viscosity below 20 c P.This outstanding property is attributed to the synergistic effects of multiple rotatable bonds and hydrogen-bond interactions.Additionally,this probe has been successfully deployed to monitor viscosity changes in various cellular compartments(i.e.,cytoplasm)and processes(such as during autophagy).This work provides a rational molecular design strategy to construct fluorescent probes with high viscosity sensitivity for exploring cell functions.

Aggregation-induced conversion from TADF to phosphorescence of gold(I)complexes with millisecond lifetimes

Long-lived luminescent materials possess wide application prospects in various areas,but their constructions still face a huge challenge,especially the achievement in solution.Manipulating aggregate is an effective method to attain intriguing luminescence,thus it is expected to build long-lived materials in solution.In this work,a series of new gold(I)complexes were developed by employing unique carbazole and phosphine as the ligands,and these resulting systems exhibited rare long lifetimes of milliseconds in the aggregate state.It was well unveiled that these complexes emitted blue thermally activated delayed fluorescence(TADF)with the lifetimes of several microseconds in dilute solution;while orange-red phosphorescence with much longer lifetimes of several milliseconds were achieved in the aggregate state.To our knowledge,this is the first implementation of aggregation-induced conversion from TADF to phosphorescence.Based on their excellent luminescent properties,we successfully applied these complexes in cell imaging and inhibition of cancer cells.

Light-and Heat-Controlled Formation of Osmanaphthalenes and Osmanaphthalynes

mple and efficient synthesis of metalla-aromatics with tailored distinctive optical,magnetic,redox,and light-emitting properties is attractive yet challenging.We have now successfully synthesized three paramagnetic osmanaphthalenes bearing different electron-donating groups as well as the first osmabenzo[b]carbazole containing an osmanaphthalene unit with four fused rings in good yields by subjecting suitable osmium carbyne precursors to a visible-light-induced protocol.In contrast,the four corresponding diamagnetic cyclic metal carbynes containing an osmanaphthalyne unit were obtained from the same osmium carbyne precursors by a heating method.The lowest-energy absorptions of the paramagnetic osmanaphthalenes are red-shifted compared to the corresponding osmanaphthalynes.Additionally,experimental observations including X-ray analysis as well as nucleus-independent chemical shift(NICS),anisotropy of the current-induced density(AICD)calculations revealed these novel osmapolycycles bearing phosphonium substituents to be of aromatic character.

Mononuclear aggregation-induced emission (AIE)-active gold(Ⅰ)-isocyanide phosphors: Contrasting phosphorescent mechanochromisms and effect of halogen substitutions on room-temperature phosphorescence nature

Developing phosphors with long-lifetime(millisecond scale or even longer) solid state room temperature phosphorescence(RTP) feature has attracted considerable attention. However, to date, stimuli-responsive phosphors with RTP nature are still rare due to the absence of effective guidelines for the exploitation of luminophors synchronously possessing stimuli-responsive and RTP characteristics. In this work,a series of mononuclear gold(Ⅰ) complexes are reported. All these complexes exhibit various solid-state RTP properties, and phosphor 1-Cl exhibits long-lived RTP behavior. The effect of halogen atoms on the RTP nature of these complexes is investigated in detail. Furthermore, the introduction of different types of halogen atoms can effectively regulate the phosphorescent mechanochromism phenomena of these gold(Ⅰ)-containing complexes. In addition, these phosphors display typical aggregation-induced emission(AIE) effect except for phosphor 5-CCl, which lacks hydrogen-bonding interactions compared with the other four phosphors. This work will be very helpful to the development of mechanical-force-responsive AIE phosphors with lasting RTP.

Aggregation Control of Hemicyanine Fluorescent Dye by Using of Cucurbit[7]uril and Pillar[6]arene

The aggregation of cyanine-based fluorescent dyes easily results in the fluorescence quenching,which limits the applications in biological science and materials science.So developing an efficient method to adjust the aggregation of cyanine dyes is very significant.In this work,we employ two different macrocyclic hosts pillar[6]arene(DEP[6])and cucurbit[7]uril(CB[7])to investigate their effects towards fluorescence spectra of dye 1.The result indicates that both of them can disrupt the aggregation of dye 1,resulting in the enhancement of its fluorescence intensity.Interestingly,investigation on the corresponding titration experiments of 1H NMR and density functional theory cal-culations shows that CB[7]and DEP[6]play different roles in the process of disaggregation.

Visible and near-infrared light activated azo dyes

The photoisomerization properties of azo derivatives have been widely used in the fields of materials and biology.One serious restriction to the development of functional azo-based materials is the necessity to trigger switching by UV light,which damage the corresponding surfaces and penetrate only partially through the matter.Therefore,developing the visible and near-infrared light activated azo switches can solve this problem.This review provides a summary of molecular design strategies for driving the isomerization of azo derivatives with visible light and near-infrared light:(1) smart design directly excited by visible light,(2) the addition of upconversion nanoparticles,(3) the employment of twophoton absorption,(4) indirect excitation in combination with metal sensitizer.

The regulation of biothiol-responsive performance and bioimaging application of benzo[c][1,2,5]oxadiazole dyes

The different oxidation states of sulphur atom play a significant role on functional materials.In this work,a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to determine thiol-containing amino acids.The result of selectivity experiments showed they detected the cysteine and homocysteine under physiological condition with negligible interference from other amino acids.In comparison to the thioether dye,the sulphone-based dye exhibited much faster response time for Cys and Hcy.However,the sulphone restricted its thiol-reactivity and bioimaging performance in living cells.By reducing the oxidation state of sulphur atom,we amazedly found that the sulfoxide-based dye still maintained high selectivity ultrafast response time for Cys/Hcy under physiological condition.It was worth mentioning that it also had high reactivity and good bioimaging performance that sulfone compounds did not have.

Stimuli-responsive organic chromic materials with near-infrared emission

Organic chromic materials that respond to external stimuli, especially in the solid state, have sparked extensive interest owing to their potential use as smart materials. In particular, the availability of chromic materials, which emit fluorescence or phosphorescence in the deep penetrating, near-infrared（NIR）region, has led to great improvements in imaging. Various methods that were commonly applied to construct chromic materials, have been reformed to develop the novel type of compounds, and some have received rewards with excellent fingdings. Relevant research achievements of practical applications have showed their potential with the changes that locate in the NIR region, while further in-depth explorations about the inherent chromic chromism are underway. In this review, several representative studies, which have led the development of responsive organic chromic materials with near-infrared emission, will be discussed.

Construction of Crown Ether-Stoppering [3]Rotaxanes Based on N-Hetero Crown Ether Host

Crown ether usually plays the role of macrocyclic host in supramolecular chemistry, but here the crown ether is also utilized as the stoppers in rotaxanes. In this work, we designed and synthesized two [3]rotaxanes containing four crown ether components by using an approach of template-directed clipping reaction, of which, two crown ether components were employed as the macrocyclic hosts to assemble the mechanically interlocked framework while another two crown ether units located on the two ends of ammonium template acting as the stoppering groups of rotaxanes. Their self-assembling process was monitored by the 1H NMR and one of the single crystal structures of [3]rotaxane was obtained.