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We demonstrate that electroactive thin films incorporating semiconducting polymers and deterministic functionalized gold nanoclusters (ncAu25) lead to the integration of the functions of resistive memory device and field-effect transistor within a single component ("mem-transistor") in a neuromorphic system. Memristor functions originate from ferrocenyl-modified gold nanoclusters (ncAu25-Fc) embedded in polymethyl-methacrylate (PMMA) and devices optimized for maximum 1/0 "flash" memory effect are found to contain 15 wt. % ncAu25-Fc. Integrated memristor and neuromorphic functions are obtained by replacing PMMA with poly(3-hexylthiophene) (P3HT) in the active layer, from which transistor effects are derived. Based on the energy band diagrams of ncAu25, PMMA, and P3HT, percolation theory is used to explain the memristor 1/0 on/off ratio as a function of ncAu25-Fc concentration. The use of ncAu25-Fc with charge-tunable, ferrocene-modified ligands is critical to achieve better cluster–polymer interfaces. Our work shows that nanostructures of polymers and metalorganic frameworks bear strong potential in the field of neuromorphic devices and circuital simplification of data storage technology. [ABSTRACT FROM AUTHOR]

A gold nanoparticle platform is described in which post-synthesis surface modifications can be conducted using kinetically-tunable strain-promoted cycloaddition chemistry, which is dependent on the electronic properties of the complementary dipolar species. This permits chemoselective reactivity with one reactive dipole over another less reactive dipole, providing exciting opportinities for kinetically-directed self-sorting strategies. [ABSTRACT FROM AUTHOR]

Dual water and organic solvent soluble 3-aryl-3-(trifluormethyl) diazirine-functionalized gold nanoparticles (AuNPs) were prepared through a place exchange reaction from triethylene glycol monomethyl ether ([EG.sub.3]-Me) capped AuNPs. These nanoparticles were fully characterized using ¹H and [sup.19]F nuclear magnetic resonance (NMR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). TGA along with ¹H NMR data allowed the determination of 15% incorporation of diazirine (Diaz) ligands onto mixed monolayer AuNPs, while TEM images showed an average diameter of 2.3 ± 0.5 nm. This information led to the estimated molecular formula of [Au.sub.400] [(S-[EG.sub.4]-Diaz).sub.40] [(S-[EG.sub.3]-Me).sub.230] for these AuNPs. It is noteworthy that high-resolution XPS was a powerful tool for quantitative analysis. Irradiation of the diazirine capped AuNPs resulted in nitrogen extrusion and the formation of a highly reactive carbene with evidence of a portion of the reaction proceeding via the diazo intermediate and thus requiring a second photon for activation. The carbene species generated was utilized to tether the attached AuNPs via insertion into C=C or O-H functionality inherent on various substrates. Here, we demonstrated that photolysis of the diazirine modified AuNPs in the presence of a variety of model carbene scavengers led to clean and efficient insertion products while maintaining their solubility in polar solvents. Key words: gold nanoparticles, water soluble, 3-aryl-3-(trifluormethyl) diazirine, carbene, photochemistry, surface modification. Des nanoparticules d'or (AuNPs) fonctionnalisee avec de la 3-aryl-3-(trifluormethyl) diazirine soluble dans un solvant a phases aqueuse et organique ont ete preparees par l'intermediaire d'une reaction d'echange a partir d'AuNP terminees par du monomethyl ether (Me) de triethylene glycol ([EG.sub.3]). Ces nanoparticules ont ete totalement caracterisees a l'aide de la spectroscopie resonance magnetique nucleaire (RMN) ¹H et [sup.19]F, microscope electronique a transmission (MET), analyse thermogravimetrique (ATG) et spectroscopie d'electrons pour analyse chimique (ESCA). Les donnees de l'ATG et de la spectroscopie RMN ¹H NMR ont permis de determiner que le taux d'incorporation des ligands de diazirine (Diaz) sur les AuNP monocouches melangees etait de 15% et les images de MET ont mis en evidence un diametre moyen de 2, 3 ± 0, 5 nm. Ces renseignements ont permis d'obtenir la formule moleculaire estimee d'[Au.sub.400][(S-[EG.sub.4]-Diaz).sub.40] [(S-[EG.sub.3]-Me).sub.230] pour ces AuNP. Il est a noter que l'ESCA a haute resolution a servi d'outil puissant d'analyse quantitative. L'irradiation des AuNP terminees par de la diazirine entraine la liberation d'azote et la formation d'un carbene hautement reactif, une partie de la reaction passant manifestement par un intermediaire diazo et necessitant ainsi un second photon pour l'activation. Les carbenes produits ont ete utilises pour fixer les AuNP en les inserant dans les fonctions C=C ou O-H sur differents substrats. Nous demontrons ici que la photolyse des AuNP modifies par la diazirine en presence de modeles de capteurs de carbene varies conduit a des produits d'insertion propres et efficaces tout en preservant leur solubilite dans des solvants polaires. [Traduit par la Redaction] Mots-cles: nanoparticules d'or, soluble dans l'eau, 3-aryl-3-(trifluormethyl) diazirine, carbene, photochimie, modification de surface., Introduction Gold nanoparticles (AuNPs) possess unique physical and chemical properties that make them outstanding candidates for numerous applications ranging from electronics, catalysis, biology, and sensor science. (1-6) Many of these [...]

Bundles of single-walled carbon nanotubes (SWCNTs) prepared by plasma torch method and further purified, are deposited over a glass coverslip to estimate the spatial resolution of tip-enhanced Raman spectroscopy measurements. For this purpose, near-field Raman maps and spectra of isolated bundles of carbon nanotubes are collected using optimized experimental conditions such as a tightly focused beam using a 1.4 numerical aperture oil immersion microscope objective and a gold coated atomic force microscope probe illuminated by a radially polarized 632.8 nm wavelength to selectively excite the localized surface plasmon confined at the extremity of the tip. The near-field nature of the collected Raman signals is evaluated through measuring the decay of the Raman signal with respect to the tip-sample separation. Key words: tip-enhanced Raman spectroscopy, localized surface plasmon resonance, near-field spectroscopy, radial polarization, atomic force microscopy, spatial resolution, enhancement factor, single-walled carbon nanotubes. Des fagots de nanofils de carbone simple-paroi, prepares par torche plasma puis purifies sont deposes sur des lamelles de microscope dans la perspective de mesurer la resolution spatiale de mesures Raman locales exaltees par effet de pointe. A cette fin, des cartographies ainsi que des spectres Raman sont collectes dans des conditions experimentales optimisees basees sur l'utilisation d'un objectif de microscope a forte ouverture numerique (O.N. 1.4) et d'une excitation avec une polarisation radiale a 632, 8 nm afin d'exciter selectivement le plasmon de surface localise et de confiner ce dernier a l'extremite de la pointe en or. Le champ proche Raman est evalue en analysant la decroissance du signal collecte en fonction de la distance entre la pointe et l'echantillon. Mots-cles: spectroscopie Raman exaltee par effet de pointe, plasmon de surface localise, microscopie en champ proche, polarisation radiale, microscopie a force atomique, resolution spatiale, facteur d'exaltation, nanofils de carbone a simple paroi., Introduction The discovery of surface-enhanced Raman spectroscopy (SERS) in the early 1970's was a milestone in improving the inherent low efficiency of inelastic Raman scattering. (1, 2) The improved sensitivity [...]

The bottom‐up synthesis of self‐assembled micro‐compartmentalised systems that mimic basic characteristics of living cells is rapidly evolving. These types of systems are termed "protocells" and can be chemically programmed to grow and divide, to send and receive chemical signals, to transcript and translate chemical information, to adhere to surfaces or to other protocells, and to perform rudimental enzyme‐mediated metabolic processes. An emerging protocell model that is attracting great attention is the colloidosome. Colloidosomes are microcapsules with a chemically crosslinked, semipermeable membrane composed of amphiphilic nanoparticles. Colloidosomes display important advantages over other protocell models (e. g. vesicles and coacervate micro‐droplets) due to their physical‐chemical properties that can be easily tuned through the careful engineering of their synthetic building blocks. In this review, we deliver an overview of the different types of colloidosomes that have been developed thus far and discuss how organic chemistry contributes to the design and bottom‐up synthesis of novel types of colloidosomes endowed with advanced chemically programmed bio‐inspired functions. [ABSTRACT FROM AUTHOR]

The name Juan Cesar Scaiano, of course, better known to most as Tito Scaiano, is synonymous with photochemistry and indeed chemistry in Canada. Since settling in Canada in 1979, Tito [...]

Irradiation of saturated monolayers of 3- and 4-substituted pyridyl diazoacetates on single-crystal Pt surfaces leads to either the corresponding reactive carbene or stable ketene intermediate with the chemoselectivity determined by the position of the photoreactive substituent on the pyridyl ring, which ultimately directs the available interactions with neighboring substrates. Key words: ketene, carbene, diazoester, saturated monolayer, photochemistry, Pt surfaces. L'irradiation de monocouches saturees de diazoacetates de pyridyles substitues dans les positions 3 et 4 sur des surfaces de monocristaux de platine conduit a la formation soit du carbene reactif correspondant ou de l'intermeediaire ceetene stable dans lesquels la chimioselectivite est deetermineee par la position du substituant photoreactif sur le noyau pyridyle qui en fin de compte dirige les interactions disponibles avec les substrats avoisinants. Mots-cles: cetene, carbene, diazoester, monocouche saturee, photochimie, surfaces de platine. [Traduit par la Redaction], Introduction The ability to precisely control the reactivity of organic molecules as saturated monolayers on metal surfaces is a significant challenge. Results of such studies remain of interest because of [...]

Azide-terminated alkyl thiolate monolayer-protected gold nanoparticles (1-[C.sub.12]MPN) with a core size of 1.8 ± 0.2 nm were prepared. 1-[C.sub.12]MPN was modified in high yields via an uncatalyzed 1,3-dipolar cycloaddition (click-type reaction) with a variety of terminal acyl-alkynes under hyperbaric conditions at 11000 atm. The resulting 1,2,3- triazole modified MPNs (2-[C.sub.12]MPN) were characterized using ¹H NMR spectroscopy and were verified by comparison of the spectra to those obtained for the products of the model reactions of 1-azidododecane with the same alkynes. TEM analysis showed that the high-pressure conditions did not affect the size of the gold core, suggesting that the only effect is to facilitate the chemical reaction on the particles. Key words: nanoparticles, hyperbaric chemistry, 1,3-dipolar cycloaddition, monolayers. On a prepare des nanoparticules d'or protegees par une monocouche d'alkylthiol (1-[C.sub.12]MPN) portant une fonction azide en position terminale et dont le diametre principal est egal a 1,8 ± 0,2 nm. Le produit 1-[C.sub.12]MPN a ete modifie avec des rendements eleves par le biais d'une cycloaddition 1,3-dipolaire non catalysee (reaction de type par un clic) avec une variete d'acyl-alcynes terminales, dans des conditions hyperbariques, a 11,000 atmospheres. Les nanoparticules d'or modifiees, protegees par une monocouche d'alkylthiol (2-[C.sub.12]MPN) et portant un cycle 1,2,3-triazole ont ete caracterisees par spectroscopie RMN du 111 et ont ete verifiees par comparaison avec les spectres obtenus pour les produits des reaction' modeles du 1-azidodecane avec les memes alcynes. Une analyse par microscopie electronique a transmission (MET) a permis de montrer que les conditions de haute pression n'ont pas affecte la taille du diametre principal de l'or suggerant que le seul effet est de faciliter la reaction chimique sur les particules. Mots-cles : nanoparticules, chimie hyperbarique, cycloaddition 1, 3-dipolaire, monocouches. [Traduit par la Redaction], Introduction The Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of azides to terminal alkynes to produce a triazole ring, the 'click' reaction, is a popular and powerful tool in organic synthesis and combinatorial [...]

To fine‐tune structure–property correlations of thiolate‐protected gold nanoclusters through post‐assembly surface modifications, we report the synthesis of the o, m, and p regioisomeric forms of the anionic azide‐functionalized [Au25(SCH2CH2‐C6H4‐N3)18]1− platform. They can undergo cluster–surface strain‐promoted alkyne–azide cycloaddition (CS‐SPAAC) chemistry with complementary strained‐alkynes. Although their optical properties are similar, the electrochemical properties appear to correlate with the position of the azido group. The ability to conduct CS‐SPAAC chemistry without altering the parent nanocluster structure is different as the isomeric form of the surface ligand is changed, with the [Au25(SCH2CH2‐p‐C6H4‐N3)18]1− isomer having the highest reaction rates, while the [Au25(SCH2CH2‐o‐C6H4‐N3)18]1− isomer is not stable following CS‐SPAAC. Single‐crystal X‐ray diffraction provide the molecular structure of the neutral forms of the three regioisomeric clusters, [Au25(SCH2CH2‐o/m/p‐C6H4‐N3]0, which illustrates correlated structural features of the central core as the position of the azido moiety is changed. [ABSTRACT FROM AUTHOR]

A maleimide-modified mixed monolayer protected gold nanoparticle (MPGN) containing maleimide-terminated dodecanethiolate/dodecanethiolate ligands is synthesized. The cycloaddition reaction has occurred more readily with N-dodecylmaleimide than with mixed monolayer MPGN with all nitrones, which has shown that the environment of the latter has affected the cycloaddition reaction.

The electron transfer (ET) reduction of benzyl benzenesulfenate ester (1) and tert-butyl benzenesulfenate ester (2) was investigated using electrochemical techniques. Analysis of the cyclic voltammetry of each compound suggests that the ET reduction proceeds via a stepwise dissociative mechanism. The voltammograms of 1 are similar to those of diaryl disulfides and it was found through controlled potential electrolysis (CPE) product studies that ET reduction leads to S--O bond cleavage. The voltammograms of 2 are dramatically different with a sharper dissociative wave occurring ata more negative peak potential. CPE experiments indicate products that result from ET leading to C--O bond cleavage in this case. DFT calculations of the singly occupied molecular orbitals (SOMOs) of 1 and 2 were performed and offer a rationale for the different reactivity of the two radical anions. Key words: sulfenate esters, dissociative electron transfer, electrochemistry, radical anions. On a etudie la reaction de reduction par transfert d'electron (TE) du benzenesulfenate de benzyle (1) et du benzenesulfenate de tert-butyle (2) en faisant appel a des techniques electrochimiques. L'analyse de la voltamperometrie cyclique de chaque compos, suggere que la reduction par TE se produit par un mecanisme par dissociations successives. Le voltamperogramme du compose 1 est semblable a celui des disulfures de diaryles et, sur la base d'etudes des produits par electrolyse a potentiel controle (EPC), on a trouve que la reduction par TE conduit a une coupure de la liaison S--O. Le voltamperogramme du compose 2 est dramatiquement different et il presente une vague dissociative qui se presente a un pic de potentiel beaucoup plus negatif. Les etudes d'EPC indiquent que, dans ce cas, les produits qui resultent d'un TE proviennent d'une coupure d'une liaison C--O. Des calculs effectues sur la base de la theorie de la densite fonctionnelle des orbitales moleculaires a occupation singulet (SOMO) des composes 1 et 2 et ils permettent de presenter une rationalisation pour les reactivites differentes des deux radicaux anions. Mots cles : esters de l'acide sulfenique, transfert d'electron avec dissociation, electrochimie, radicaux anions. [Traduit par la Redaction], Introduction A major focus of our group has been the study of dissociative electron transfer (ET) reactions through electrochemical methods. The work provides an opportunity to investigate many aspects of [...]

The reductive desorption of a self-assembled monolayer (SAM) of a fluorescent thiol molecule (BodipyC10SH) from Au was characterized and monitored for the first time with electrochemistry and epi-fluorescence microscopy. The observations reveal that the selective desorption might have profound application in the creation of a thiol-modified surface with a desired pattern and multifunction, and in the electrofluorescence technique in the detection strategy used for SAM array sensors.

A series of monolayer-protected clusters (MPCs) modified with a photoreactive [4-(11-mercaptoundecyl)phenyl](2-methylphenyl)methanone (1) moiety have been prepared where 1 is co-absorbed to the MPC surface with dodecanethiol, octadecanethiol, or 11-mercaptoundecanoic acid methyl ester. Upon irradiation the MPC-anchored 1 reacts efficiently through its triplet excited states, yielding 1,4-biradicals that collapse to synthetically useful, long-lived photodienol intermediates, which can be efficiently trapped in Diels-Alder type chemistry by dienophiles--namely, dimethyl acetylenediearboxylate (DMAD). In all cases the Diels-Alder trapping of the dienol occurred efficiently resulting in > 60% conversion to the Diels-Alder adduct. This indicates that the local environment surrounding 1 did not influence its ability to react via the Diels-Alder reaction; however, the reaction could not be taken to completion. The inability to react completely is attributed to 1 binding to distinct sites on the MPC core; there are edge, vertice, and terrace sites. Selective population of these specific sites and the subsequent irradiations show that MPCs with 1 anchored predominantly at edge and verfice sites results in an extent of reaction of 85 [+ or -]3%, whereas selectively populating the terrace sites results in an extent of reaction of 36 [+ or -] 2%. These results suggest that 1 anchored to edge and vertice sites is more reactive to the Diels-Alder reaction than that involving terrace sites. Key words: monolayer protected cluster, site selective reactivity, Diels-Alder, photochemistry.

A series of ferrocenyl substituted azines (1-Fc/Ar, where Ar = 4-N[O.sub.2][C.sub.6][H.sub.4], 4-CN[C.sub.6][H.sub.4], 4-OC[H.sub.3][C.sub.6][H.sub.4], [C.sub.5][H.sub.4]N, ferrocene, anthracene, and pyrene) were investigated by electrochemical ad photochemical techniques. All the 1-Fc/Ar exhibited oxidation waves within 60 mV of each other, consistent with the expected oxidation of the ferrocene moiety. The reduction properties of 1-Fc/Ar is governed by the nature of the Ar substituent. The standard reduction potentials suggest that ferrocene has comparable electron donating abilities as a 4-methoxyphenyl and 4-dimethyl-aminopbenyl group. The anthracenyl azines exhibit one-electron reversible reduction followed by dimerization of the radical anion resulting in dimerization rate constants (k.sub.d) between 5.1 x [10.sup.4] and 1.5 x [10.sup.5] [M.sup.-1] [s.sup.-1]. 1-Fc/Anth and related azines undergo photochemical E/Z isomerization of the C=N bonds to produce E/Z and Z/Z isomers from the thermodynamically most stable E/E form. Fluorescence at 77 K, was observed for these compounds only after long-wavelength irradiation to produce a mixture of E/E, E/Z, and Z/Z isomers. Fluorescence quantum yields of 0.042, 0.090, and 0.176 were determined for 2-Anth/H, 2-Anth/Anth, and 1-Fc /Anth, respectively. The electrochemical, photochemical, and X-ray data suggest that the azine unit is a conjugation "limiter" and may be a general characteristic of azine molecules. Key words: azines, electrochemistry, cyclic voltammetry, reduction, electron transfer.

On 19 September 2017, Canadian chemistry lost one of our foremost physical organic chemists, James Peter Guthrie, to Guillain-Barre Syndrome in his 76th year. Peter Guthrie was born in rural [...]

The photoelectrochemical behavior of two polymers of the polythiophene series containing electron-acceptor groups in the main chain is studied and compared to that of the nonmodified polymer, poly(2,2'-bithiophene), PBT. The values of external quantum efficiency are estimated in a liquid-cell arrangement to be 0.27 and 0.19% for modified and nonmodified polymers, respectively.

The homogeneous and heterogeneous reductions of the endoperoxides 9,10-epidioxyanthracene (DPA-O2) and 9,10-dimethyl-9,10-epidioxyanthracene (DMA-O2) are investigated. The initial electron transfer (ET) reduction DPA-O2 and DMA-O2 follows a dissociative mechanism with fragmentation of the O-O bond to yield a distonic radical anion.

Cancer targeting can be used for both tumor diagnosis and therapy. Recently, gold nanoparticles (AuNPs) have found utility in this field as they are very small in size, and thus display an enhanced permeability and retention effect, allowing them to be taken up by tumor cells through 'passive targeting.' However, this accumulation is non-specific. Conversely, AuNPs functionalized with targeting entities such as peptides, antibodies, or small molecules can specifically target tumors through interaction with cancer-specific protein receptors. In this study, targeted AuNPs were developed using an azide-modified peptide that was able to react with alkyne-functionalized AuNPs through an interfacial strain-promoted azide-alkyne cycloaddition. Small (3 nm) AuNPs were made water-soluble through PEGylation and functionalized with dibenzocyclooctyne to add the alkyne functionality. For the targeting entity, a pan-bombesin peptide ([D-Phe6,β-Ala11,Phe13,Nle14]bombesin(6-14)) was chosen as it binds to all four receptor subtypes of the gastrin releasing peptide receptor, which is highly expressed in prostate cancer. Prostate cancer (PC-3) cells were incubated with the targeted AuNPs and studied via transmission electron microscopy. AuNPs conjugated with bombesin showed higher accumulation in PC-3 cells than either the blocking or control studies. These results suggest that these small, water-soluble, bombesin-functionalized AuNPs have potential applications in targeting prostate cancer as diagnostic or therapeutic entities. [ABSTRACT FROM AUTHOR]

The Diels-Alder reaction was employed to chemically modify the two-dimensional monolayer (SAM) surfaces, which includes the monolayer-protected gold nanoparticles (MPNs). The analysis reveals that various hyperbaric pressure conditions can be used to facilitate such reactions.

In this study, we report the design, synthesis, and characterization of small 3 nm water soluble gold nanoparticles (AuNPs) that feature cyclopropenone-masked strained alkyne moieties capable of undergoing interfacial strain-promoted cycloaddition (i-SPAAC) with azides after exposure to UV-A light. A strained alkyne precursor was incorporated onto AuNPs by direct ligand exchange of a thiol-modified cyclopropenone-masked dibenzocyclooctyne (photoDIBO) ligand. These photoDIBO-AuNPs were characterized by 1H NMR, IR, and UV/Vis spectroscopy, as well as transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), and the extent of modification was quantified. Upon irradiation with UV-A light, photoDIBO-AuNPs underwent efficient and quantitative regeneration of the parent strained alkyne by photochemical decarbonylation to afford DIBO-derivatized AuNPs. DIBO-AuNPs were found to react cleanly and rapidly ( k=5.3×10−2 m−1 s−1) by an interfacial strain-promoted alkyne-azide cycloadditon (i-SPAAC) with benzyl azide, which served as a simple model system. Furthermore, DIBO-AuNPs were reacted with various azides and a nitrone (interfacial strain-promoted alkyne-nitrone cycloaddition, i -SPANC) to showcase the generality of this approach for the facile modification of AuNP surfaces and their properties. The cyclopropenone-based photo-triggered click chemistry at the interface of water-soluble AuNPs offers exciting opportunities for the atom-by-atom control and assembly of functional materials for applications in materials and biomaterials science as well as in chemical biology. [ABSTRACT FROM AUTHOR]

The preparation of the ferrocene-based reagents FcSSiMe3 ( 1) and fc(SSiMe3)2 ( 2) [Fc = (η5-C5H5)Fe(η5-C5H4)-; fc = Fe(η5-C5H4)2-] is reported together with their use in the formation of the tetrahedral zinc complexes [( N, N′-tmeda)Zn(SFc)2] ( 3a) and [( N, N′-tmeda)Zn(S2fc)] ( 4a), respectively (tmeda = tetramethylethylenediamine). The structures of these coordination complexes are compared to the new ferroceneselenolates [( N, N′-tmeda)Zn(SeFc)2] ( 3b) and [( N, N′-tmeda)Zn(Se2fc)] ( 4b), themselves prepared using FcSeSiMe3 and fc(SeSiMe3)2, respectively. The synthesis and characterization of dimeric [Cd2(µ-EFc)2(EFc)2(PPr3)2] ( 5a, E = S; 5b, E = Se) are also described. [ABSTRACT FROM AUTHOR]

Front Cover: Colloidosomes as a Protocell Model: Engineering Life-Like Behaviour through Organic Chemistry (Eur. J. Org. B The Front Cover b illustrates an adapted brightfield microscopy image of colloidosome protocells produced from gold nanoparticles using the Pickering emulsions technique. The artwork highlights the role of organic chemistry in the engineering of colloidosomes with life-like behaviors, which is the subject of this review article. [Extracted from the article]

The maleimide moiety can undergo a wide variety of organic reactions, including Diels-Alder reactions, dipolar cycloadditions, and Michael-type additions, making it a suitable moiety for further elaboration of the functionality at the interface of gold nanoparticles (AuNPs) through key reactions that are useful in a host of applications. This account will cover: (1) our approach to prepare maleimide-AuNPs, (2) our survey of the scope of the reactivity of organic-solvent-soluble maleimide-AuNPs, which are very slow, impractical, and required the development of high-pressure techniques in AuNP chemistry yielding dramatic results, and (3) the extension of these ideas to prepare water-soluble small AuNPs to expand the scope of the organic transformation to aqueous environments. Within each of these sections there were challenges that had to be overcome, and we will describe the evolution of the ideas so that readers can get a glimpse of our thinking and problem solving as we proceeded. 1 Introduction 2 Maleimide-AuNPs: The Synthetic Strategy 3 Reactivity of the Organic-Solvent-Soluble Maleimide-AuNP Template 4 Synthesis of the Water-Soluble Maleimide-AuNP Template 5 Reactivity of the Water-Soluble Maleimide-AuNP Template 6 Concluding Remarks. [ABSTRACT FROM AUTHOR]

An azide-functionalized nitronyl nitroxide was synthesized and its reactivity towards the Staudinger-Bertozzi ligation was explored. Whereas a model reaction in solution showed the conversion of nitronyl nitroxide to an imino nitroxide radical, the same reaction at the interface of gold nanoparticles allowed for successful covalent incorporation of the nitronyl nitroxide radical onto the nanoparticles. [ABSTRACT FROM AUTHOR]

Prepared by simple pour and mix chemistry, gold nanosponges (AuNS) are versatile structures for surface-enhanced Raman spectroscopy (SERS). An investigation into the enhancement is performed by relating the nanostructure's morphology to the SERS signal. The potential of the AuNS in SERS-based molecular and biomolecular detection is introduced. [ABSTRACT FROM AUTHOR]

Maleimide-terminated triethylene glycol thiolate monolayer-protected gold nanoparticles (Mal -EG4-AuNPs) with a core size of 2.5 ± 0.7 nm were prepared. Mal-EG4-AuNPs were modified in high yields via interfacial 1,3-dipolar cycloaddition and Diels-Alder reactions with a variety of nitrones and dienes, respectively. The resulting cycloadduct-modified AuNPs were characterized using 1H NMR spectroscopy and were verified by comparison of the spectra to those of the products of the model reactions with the same nitrones and dienes. TEM analysis showed that the reaction conditions did not affect the shape or size of the gold core, suggesting that this is an efficient methodology to modify small water soluble AuNPs under ambient pressure and biological temperature with high yields and a reasonable reaction time. [ABSTRACT FROM AUTHOR]

An efficient method for the large-scale preparation of rhodamine B clickable derivatives has been developed. Starting from inexpensive rhodamine B as the starting material it was possible to functionalize the carboxylic functionality of rhodamine B with an azide, a strained-alkyne, a substituted triphenylphosphine, a thiol, and a maleimide. Through the synthetic strategy it was possible to obtain stable and pure clickable rhodamine compounds that can be readily used not only for chemoselectively probing biomolecules, but also for materials science. [ABSTRACT FROM AUTHOR]

A protection–deprotection strategy for strained alkynes used for bioorthogonal chemistry is reported. A strained alkyne can be protected with dicobalt–octacarbonyl and we demonstrate for the first time that a strained alkyne can be re-formed and isolated under mild reaction conditions for further bioorthogonal reactivity. The protection–deprotection strategy herein reported will expand the versatility of strained alkynes for the preparation of substrates in chemical biology and materials applications. [ABSTRACT FROM AUTHOR]

Au clusters with protecting organothiolate ligands and core diameters less than 2 nm are molecule-like structures, suitable for catalysis, optoelectronics and biology applications. The spectroscopy and electrochemistry of Au250 (Au25[(SCH2CH2Ph)18], SCH2CH2Ph=2-phenylethanethiol) allowed us to construct a Latimer-type diagram for the first time, which revealed a rich photoelectrochemistry of the cluster and the unique relationship to its various oxidation states and corresponding excited states. The occurrence of cluster electrochemiluminescence (ECL) was examined in the presence of tri- n-propylamine (TPrA) as a co-reactant and was discovered to be in the near-infrared (NIR) region with peak wavelengths of 860, 865, and 960 nm, emitted by Au25+*, Au250*, and Au25−*, respectively. The light emissions, with an efficiency up to 103 % relative to that of the efficient Ru(bpy)32+/TPrA system, depended on the kinetics of the reactions between the electrogenerated TPrA radical and Au25 z ( z=2+, 1+, 1−, and 2−) in the vicinity of the electrode or the bulk Au250. These thermodynamic and kinetic origins were further explored by means of spooling ECL and photoluminescence spectroscopy during a sweep of the potential or at a constant potential applied to the working electrode. NIR-ECL emissions of the cluster can be tuned in wavelength and intensity by adjusting the applied potential and TPrA concentration based on the above discoveries. [ABSTRACT FROM AUTHOR]