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This mini-review highlights the transformative potential of benzothiazole (BTz)- and benzoxazole (BOz)-based boron-complexed dyes. It represents an innovative evolution of the classic boron-dipyrromethene (BODIPY) structure, which is well established for its superior photophysical properties. Incorporating BTz- or BOz-ligands into the borane (-BR 2 ) component, originates more electron-deficient architecture, enabling novel modes of complexation and addressing limitations such as spectral overlap and self-quenching in traditional BODIPY dyes. The review focuses on the remarkable versatility of boron-benzothiazole (BOBTz)- and boron-benzoxazole (BOBOz)-based complexes, particularly in three rapidly advancing fields: organic light emitting diode (LED) technology, bioimaging, and mechanochromic luminescence (MCL). Over the past 15 years, these complexes have demonstrated exceptional adaptability, showcasing enhanced properties like high fluorescence quantum yields, large molar extinction coefficients, and tunable emissions across visible and near-infrared spectra. The insights described in this review highlight the major role of BOBTz- and BOBOz-complexes in shaping innovative, and sustainable advanced materials while addressing emerging challenges in modern materials science. Besides, the refining of both BOBTz- and BOBOz-complexes offers exciting prospects for technological challenges such as energy-efficient lighting, non-invasive imaging, and creating stimuli-responsive materials for next-generation sensors. Moreover, the environmental sustainability of these materials, including green synthesis approaches and recyclable components represents an important frontier for future exploration., (© 2025 The Author(s). Macromolecular Rapid Communications published by Wiley‐VCH GmbH.)

Fluoride-ion batteries are a promising alternative to lithium-ion batteries by dint of the greater crustal abundance of fluorine and the potential to alleviate the need for metal electrodeposition. However, conventional metal fluoride cathodes typically rely on conversion-type reactions that require propagation of a reaction-diffusion front, thereby limiting cycling performance and rate capability. In contrast, the topochemical insertion of fluoride-ions in periodic solids remains a relatively unexplored approach. Here, we explore the mechanisms of fluoridation of Bi 2 PdO 4 and Bi 1.6 Pb 0.4 PtO 4 insertion hosts that possess capacious tunnels that can accommodate fluoride-ions with a particular emphasis on elucidating the role of stereochemical expression of bismuth 6s 2 lone pairs in mediating anion diffusion. We reveal that the topochemical solution-phase insertion and deinsertion of fluoride-ions at room temperature is mediated by redox reactions at platinum and palladium centers but involves multi-center synergies between d- and p-block atoms across the one-dimensional (1D) tunnel structure. While Pt and Pd centers mediate redox reactions, the stereochemically active lone pair electrons of Bi 3+ play a pivotal role in facilitating reversible fluoride-ion diffusion. Consequently, Bi 1.6 Pb 0.4 PtO 4 and Bi 2 PdO 4 can be reversibly fluoridated with full recovery of the crystal lattice and with minimal alteration of the unit cell volume. The results reveal a key principle that the stereochemical activity of p-block electron lone pairs can be harnessed to modulate anion-lattice interactions and mediate facile anion diffusion., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Demand for lithium is expected to quadruple by the end of the decade. Without new sources of production, the supply-demand curve is expected to invert. Traditional geological reserves will not be able to meet the anticipated gap, thus unconventional sources of lithium will need to be utilized, setting the stage for fierce competition for perhaps the most critical of mineral resources required for the energy transition. Direct Lithium Extraction refers to the umbrella of technologies being developed to access lithium from unconventional sources. Electrochemical extraction offers significant promise for its selectivity and low operating cost when coupled with renewable energy. This review aims to describe materials and process design considerations for electrochemical extraction of lithium from aqueous sources with a specific emphasis on ζ-V2O5 designed in our research group as an insertion host. We point to specific strategies for improving capacity and selectivity for electrochemical lithium extraction based on materials design across length scales. Strategies range from site-selective modification of insertion hosts to controlled tortuosity of ion diffusion pathways in porous electrode architectures. Electrochemical lithium extraction from unconventional sources stands poised to be a linchpin of a sustainable economy when coupled with cleaning of wastewater, hydrogen generation, and recovery of ancillary critical metals., (Copyright 2024 Harris E. Kohl, Carlos A. Larriuz, Andrew Ezazi, Mohammed Al-Hashimi, Hassan S. Bazzi, Sarbajit Banerjee. License: This work is licensed under a Creative Commons Attribution 4.0 International License.)

Software-Defined Networking (SDN) revolutionizes network management by decoupling control plane functionality from data plane devices, enabling the centralized control and programmability of network behavior. This paper uses the ternary system to improve the Central Processing Unit (CPU) inside the SDN controller to enhance network management. The Multiple-Valued Logic (MVL) circuit shows remarkable improvement compared to the binary circuit regarding the chip area, propagation delay, and energy consumption. Moreover, the Carbon Nanotube Field-Effect Transistor (CNTFET) shows improvement compared to other transistor technologies regarding energy efficiency and circuit speed. To the best of our knowledge, this is the first time that a ternary design has been applied inside the CPU of an SDN controller. Earlier studies focused on Ternary Content-Addressable Memory (TCAM) in SDN. This paper proposes a new 1-trit Ternary Full Adder (TFA) to decrease the propagation delay and the Power-Delay Product (PDP). The proposed design is compared to the latest 17 designs, including 15 designs that are 1-trit TFA CNTFET-based, 2-bit binary FA FinFET-based, and 2-bit binary FA CMOS-based, using the HSPICE simulator, to optimize the CPU utilization in SDN environments, thereby enhancing programmability. The results show the success of the proposed design in reducing the propagation delays by over 99% compared to the 2-bit binary FA CMOS-based design, over 78% compared to the 2-bit binary FA FinFET-based design, over 91% compared to the worst-case TFA, and over 49% compared to the best-case TFAs.

The synthesis and characterization of asymmetric alkoxy- are reported, fluoro-benzothiadiazole (BT) acceptor core derivatized with a series of six different heterocycles (selenophene, thiophene, furan, 5-thiazole, 2-thiazole and 2-oxazole). The effect of the flanked-heterocycles containing different chalcogen atoms of the six homopolymers (HPX) is studied using optical, thermal, electrochemical, and computational analysis. Computational calculations indicate a strong relationship between the most stable conformation for each homopolymer and their bearing heterocycle, thus homopolymers HPSe', HPTp', HPFu', and HPTzC5, adopted the syn-syn and syn-anti conformations due to their noncovalent interactions with shorter distances, while HPTzC2' and HPOx' demonstrate preference for the anti-anti conformation. Optical property studies of the homopolymers reveal a strong red-shift in solution and film upon exchanging the chalcogen atom from Oxygen < Sulfur < Selenium in HPFu, HPTp, and HPSe, respectively. In addition, deeper highest occupied molecular orbital (HOMO) energy levels are observed when the donor-acceptor moieties (HPSe, HPTp, and HPFu) are substituted for the acceptor-acceptor systems such as HPTzC5, HPTzC2, and HPOx. Improved packing and morphology are exhibited for the donor-acceptor homopolymers. Thus, having a flanked heterocycle containing different chalcogen-atoms in polymeric systems is one way of tuning the physicochemical properties of conjugated materials for optoelectronic applications., (© 2022 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH.)

The synthesis and applications of ring-opening metathesis polymerization (ROMP) derived poly(olefins) have emerged as an exciting area of great interest in the field of biomaterials science. The major focus of this mini-review is to present recent advances in the synthesis of functional materials using ROMP-derived poly(olefins) utilized for drug release, sensing, and cellular uptake in the past seven years (2015-2022). This review reveals that materials synthesized by ROMP-derived well-defined functional poly(olefins) stand to be highly promising systems for medical as well as biological studies. Thus, this review may prove to be beneficial for the design and development of new smart and flexible-functionality ROMP-based polymeric materials for various biological applications., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Novel methods to synthesize electron-deficient π-conjugated polymers utilizing transition-metal-free coupling reactions for the use of nonfunctionalized monomers are attractive due to their improved atom economy and environmental prospective. Herein we describe the use of i PrMgCl·LiCl complex to afford thiazole-based conjugated polymers in the absence of any transition metal catalyst, that enables access to well-defined polymers with good molecular weights. The mechanistically distinct polymerizations proceeded via nucleophilic aromatic substitution (S N Ar) reaction supported by density functional theory (DFT) calculations. This work demonstrates the first example of fully conjugated thiazole-based aromatic homopolymers without the need of any transition metal catalyst.

There a few reports of rhodamine-based fluorescent sensors for selective detection of only Al 3+ , due to the challenge of identifying a suitable ligand for binding Al 3+ ion. The use of fluorophore moieties appended to a polymer backbone for sensing applications is far from mature. Here, we report a new fluorescent probe/monomer 4 and its ROMP derived polymer P for specific detection of Al 3+ ions. Both monomer 4 and its polymer P exhibit high selectivity toward only Al 3+ with no interference from other metal ions, having a limit detection of 0.5 and 2.1 µM, respectively. The reversible recognition of monomer 4 and P for Al 3+ was also proved in presence of Na 2 EDTA by both UV-Vis and fluorometric titration. The experimental data indicates the behavior of 4 and P toward Al 3+ is pH independent in medium conditions. In addition, the switch-on luminescence response of 4 at acidic pH (0 < 5.0), allowed us to specifically stain lysosomes (pH ~ 4.5-5.0) in live cells.

Functionalization of polyolefins, in particular polyisobutylene, remains a relatively unexplored application for the Michael reaction. This work evaluates the potential of polyisobutylene acrylate (PIBA) chain-end modification via organocatalyzed thiol-Michael and aza-Michael additions. A series of chain-end functional polyisobutylene oligomers are prepared using "click" reactions of thiols or amines to PIBA in the presence of 0.02 equivalents of organocatalyst. Reaction kinetics and chain-end transformations are monitored using NMR spectroscopy and the macromolecular products are characterized by size exclusion chromatography. Further potential of this synthetic strategy is illustrated by thiol-Michael addition of thiols formed in situ via nucleophilic thiolactone ring opening. The obtained results provide an efficient method for the preparation of functional polyisobutylene oligomers that can be utilized in a broad range of potential applications., (© 2020 Wiley-VCH GmbH.)

Carbon monoxide (CO) is an important biological gasotransmitter in living cells. Precise spatial and temporal control over release of CO is a major requirement for clinical application. To date, the most reported carbon monoxide releasing materials use expensive fabrication methods and require harmful and poorly designed tissue-penetrating UV irradiation to initiate the CO release precisely at infected sites. Herein, we report the first example of utilizing a green light-responsive CO-releasing polymer P synthesized via ring-opening metathesis polymerization. Both monomer M and polymer P were very stable under dark conditions and CO release was effectively triggered using minimal power and low energy wavelength irradiation (550 nm, ≤28 mW). Time-dependent density functional theory (TD-DFT) calculations were carried out to simulate the electronic transition and insight into the nature of the excitations for both L and M . TD-DFT calculations indicate that the absorption peak of M is mainly due to the excitation of the seventh singlet excited state, S7. Furthermore, stretchable materials using polytetrafluoroethylene (PTFE) strips based on P were fabricated to afford P-PTFE, which can be used as a simple, inexpensive, and portable CO storage bandage. Insignificant cytotoxicity as well as cell permeability was found for M and P against human embryonic kidney cells.

TPEN is an amino chelator of transition metals that is effective at the cellular and whole organism levels. Although TPEN of often used as a selective zinc chelators, it has affinity for copper and iron and has been shown to chelate both biologically. We have previously shown that TPEN selectively kills colon cancer cells based on its ability to chelate copper, which is highly enriched in colon cancer cells. The TPEN-copper complex is redox active thus allowing for increased ROS production in cancer cells and as such cellular toxicity. Here we generate TPEN derivatives with the goal of increasing its selectivity for copper while minimizing zinc chelation to reduce potential side effects. We show that one of these derivatives, TPEEN despite the fact that it exhibits reduced affinity for transition metals, is effective at inducing cell death in breast cancer cells, and exhibits less toxicity to normal breast cells. The toxicity effect of the both chelators coupled to the metal content of the different cell types reveals that they exhibit their toxicity through chelating redox active metals (iron and copper). As such TPEEN is an important novel chelators that can be exploited in anti-cancer therapies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Low-viscosity poly(α-olefin)s (PAOs) either alone or with functional hydrocarbon oligomer cosolvents are nontoxic, nonvolatile, recyclable solvent systems that effectively and efficiently sequester trace amounts of nonpolar organic compounds such as benzene and halogenated organics from water. More polar compounds including perfluorooctanoic acid and nitrobenzene or water-miscible compounds such as THF and triethylamine can also be sequestered if the PAO phase contains an H-bonding PAO-anchored cosolvent., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Sequence-defined polymers with customizable sequences, monodispersity, substantial length, and large chemical diversity are of great interest to mimic the efficiency and selectivity of biopolymers. We report an efficient, facile, and scalable synthetic route to introduce many chemical functionalities, such as amino acids and sugars in nucleic acids and sequence-controlled oligophosphodiesters. Through achiral tertiary amine molecules that are perfectly compatible with automated DNA synthesis, readily available amines or azides can be turned into phosphoramidites in two steps only. Individual attachment yields on nucleic acids and artificial oligophosphodiesters using automated solid-phase synthesis (SPS) were >90% in almost all cases. Using this method, multiple water-soluble sequence-defined oligomers bearing a range of functional groups in precise sequences could be synthesized and purified in high yields. The method described herein significantly expands the library of available functionalities for nucleic acids and sequence-controlled polymers.

As colloidal self-assembly increasingly approaches the complexity of natural systems, an ongoing challenge is to generate non-centrosymmetric structures. For example, patchy, Janus or living crystallization particles have significantly advanced the area of polymer assembly. It has remained difficult, however, to devise polymer particles that associate in a directional manner, with controlled valency and recognition motifs. Here, we present a method to transfer DNA patterns from a DNA cage to a polymeric nanoparticle encapsulated inside the cage in three dimensions. The resulting DNA-imprinted particles (DIPs), which are 'moulded' on the inside of the DNA cage, consist of a monodisperse crosslinked polymer core with a predetermined pattern of different DNA strands covalently 'printed' on their exterior, and further assemble with programmability and directionality. The number, orientation and sequence of DNA strands grafted onto the polymeric core can be controlled during the process, and the strands are addressable independently of each other.

The title molecules are sought in connection with various synthetic applications. The aliphatic fluorous alcohols R f n CH 2 OH (R f n = CF 3 (CF 2 ) n -1 ; n = 11, 13, 15) are converted to the triflates R f n CH 2 OTf (Tf 2 O, pyridine; 22-61%) and then to R f n CH 2 I (NaI, acetone; 58-69%). Subsequent reactions with NaOCl/HCl give iodine(III) dichlorides R f n CH 2 ICl 2 ( n = 11, 13; 33-81%), which slowly evolve Cl 2 . The ethereal fluorous alcohols CF 3 CF 2 CF 2 O(CF(CF 3 )CF 2 O) x CF(CF 3 )CH 2 OH ( x = 2-5) are similarly converted to triflates and then to iodides, but efforts to generate the corresponding dichlorides fail. Substrates lacking a methylene group, R f n I, are also inert, but additions of TMSCl to bis(trifluoroacetates) R f n I(OCOCF 3 ) 2 appear to generate R f n ICl 2 , which rapidly evolve Cl 2 . The aromatic fluorous iodides 1,3-R f6 C 6 H 4 I, 1,4-R f6 C 6 H 4 I, and 1,3-R f10 C 6 H 4 I are prepared from the corresponding diiodides, copper, and R f n I (110-130 °C, 50-60%), and afford quite stable R f n C 6 H 4 ICl 2 species upon reaction with NaOCl/HCl (80-89%). Iodinations of 1,3-(R f6 ) 2 C 6 H 4 and 1,3-(R f8 CH 2 CH 2 ) 2 C 6 H 4 (NIS or I 2 /H 5 IO 6 ) give 1,3,5-(R f6 ) 2 C 6 H 3 I and 1,2,4-(R f8 CH 2 CH 2 ) 2 C 6 H 3 I (77-93%). The former, the crystal structure of which is determined, reacts with Cl 2 to give a 75:25 ArICl 2 /ArI mixture, but partial Cl 2 evolution occurs upon work-up. The latter gives the easily isolated dichloride 1,2,4-(R f8 CH 2 CH 2 ) 2 C 6 H 3 ICl 2 (89%). The relative thermodynamic ease of dichlorination of these and other iodine(I) compounds is probed by DFT calculations.

This paper reports the efficient synthesis of the first class of polyisobutylene(PIB)-supported palladium-PEPPSI precatalyst (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation). The new complexes are employed in Buchwald-Hartwig amination of aryl chlorides and are found to be reasonably active in the titled cross-coupling reaction. The supported catalysts are tested in polar (1,4-dioxane and 1,2-dimethoxyethane) as well as in aliphatic reaction media (toluene and n-heptane) and display superior activity in the highly lipophilic solvent (n-heptane). The catalytic efficacy of PIB-Pd-PEPPSI precatalyst is measured to be comparable to its nonsupported analog. Pd-leaching is determined by inductively coupled plasma mass spectrometry (ICP-MS) after a simple liquid/liquid extraction and is found to be 2 ppb in the product phase, translating into a recovery of ≈99.8% of the palladium., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This study describes the use of polyisobutylene (PIB) to phase-anchor pyridine ligands that form a phase-separable Grubbs third-generation catalyst. We further show that this complex is useful in ring-opening metathesis polymerization (ROMP) reactions. These PIB-bound pyridine-ligated Grubbs catalysts provide the same benefits of control over polymer chain growth and polydispersity of the product as their low-molecular-weight analogs and reduce Ru leaching in ROMP products from approximately 16% (820 ppm residues) as seen with a similar pyridine-ligated catalyst to a value of approximately 3% (160 ppm residues). These labile ligands are shown to be as effective at generating separable metal complexes as less labile PIB-functionalized N-heterocyclic carbene catalyst ligands that are typically used for immobilization but that require a multistep synthesis., Competing Interests: The authors declare no competing financial interest.

The fluorous alkenes H 2 C[double bond, length as m-dash]CHR fn (R fn = (CF 2 ) n-1 CF 3 ; n = 8, 10) undergo the Mizoroki-Heck reaction with a variety of aromatic monobromides and polybromides such as 1,3- and 1,4-C 6 H 4 Br 2 , 1,3,5-C 6 H 3 Br 3 , 1,3,5-C 6 H 3 Br 2 Cl, 1,4-XC 6 H 4 Br (X = CF 3 , R f8 , COCH 3 , CN, 1,4-OC 6 H 4 Br), 1,2-O 2 NC 6 H 4 Br, 5-bromoisoquinoline, 5-bromopyrimidine, 3-bromo-5-methoxypyridine, and 3,5-dibromopyridine (sixteen examples, 78% average isolated yield). Typically, 1.2-2.4 equiv. of alkene are employed per Ar-Br bond, together with Pd(OAc) 2 catalyst (4-5 mol%/Ar-Br bond), n-Bu 4 N + Br - (0.8-1.0 equiv./Ar-Br bond), NaOAc (1.2-2.4 equiv./Ar-Br bond), and 3 : 1 w/w DMF/THF as solvent (120 °C). No effort is necessary to exclude air or moisture, and reactions may be conducted on >10 g scales. Only E isomers of the products Ar(CH[double bond, length as m-dash]CHR fn ) m are detected. Thirteen representative examples are hydrogenated (Pd/C, balloon pressure H 2 ), giving Ar(CH 2 CH 2 R fn ) m (92% average isolated yield).

We report a micelle-templated method to enhance the reactivity of DNA with highly hydrophobic molecules. Lipids, chromophores and polymers can be conjugated to DNA in high yield and under mild conditions. This method expands the range of DNA-templated reactions for DNA-encoded libraries, oligonucleotide and drug delivery, nanopore mimetics and DNA nanotechnology.

A major challenge in lubrication technology is to enhance lubricant performance at extreme temperatures that exceed conventional engine oil thermal degradation limits. Soft noble metals such as silver have low reactivity and shear strength, which make them ideal solid lubricants for wear protection and friction reduction between contacting surfaces at high temperatures. However, achieving adequate dispersion in engine lubricants and metallic silver deposition over predetermined temperatures ranges presents a significant chemical challenge. Here we report the synthesis, characterization, and tribological implementation of the trimeric silver pyrazolate complex, [Ag(3,5-dimethyl-4-n-hexyl-pyrazolate)]3 (1). This complex is oil-soluble and undergoes clean thermolysis at ∼310 °C to deposit lubricious, protective metallic silver particles on metal/metal oxide surfaces. Temperature-controlled tribometer tests show that greater than 1 wt % loading of 1 reduces wear by 60% in PAO4, a poly-α-olefin lubricant base fluid, and by 70% in a commercial fully formulated 15W40 motor oil (FF oil). This silver-organic complex also imparts sufficient friction reduction so that the tribological transition from oil as the primary lubricant through its thermal degradation, to 1 as the primary lubricant, is experimentally undetectable.

Correction for 'Antisense precision polymer micelles require less poly(ethylenimine) for efficient gene knockdown' by Johans J. Fakhoury, et al., Nanoscale, 2015, 7, 20625-20634.

Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. This review highlights some of the history of efforts to address these problems, first discussing the problem in the context of reactions like ring-closing metathesis and cross metathesis catalysis used in the synthesis of low molecular weight compounds. It then discusses in more detail progress in dealing with these issues in ring opening metathesis polymerization chemistry. Such approaches depend on a biphasic solid/liquid or liquid separation and can use either always biphasic or sometimes biphasic systems and approaches to this problem using insoluble inorganic supports, insoluble crosslinked polymeric organic supports, soluble polymeric supports, ionic liquids and fluorous phases are discussed.

We report the first soluble poly(3-dodecyl tellurophenylene-vinylene) polymer ( P3TeV ) by Stille copolymerization and compare its properties to the analogous thiophene and selenophene containing polymers. The optical band gap of the polymers is shown to systematically decrease as the size of the heteroatom is increased, mainly as a result of a stabilization of the LUMO energy, resulting in a small band gap of 1.4 eV for P3TeV . Field effect transistors measurements in variety of architectures demonstrate that the selenophene polymer exhibits the highest mobility, highlighting that increasing the size of the heteroatom is not always beneficial for charge transport.

Therapeutic nucleic acids are powerful molecules for shutting down protein expression. However, their cellular uptake is poor and requires transport vectors, such as cationic polymers. Of these, poly(ethylenimine) (PEI) has been shown to be an efficient vehicle for nucleic acid transport into cells. However, cytotoxicity has been a major hurdle in the development of PEI-DNA complexes as clinically viable therapeutics. We have synthesized antisense-polymer conjugates, where the polymeric block is completely monodisperse and sequence-controlled. Depending on the polymer sequence, these can self-assemble to produce micelles of very low polydispersity. The introduction of linear poly(ethylenimine) to these micelles leads to aggregation into size-defined PEI-mediated superstructures. Subsequently, both cellular uptake and gene silencing are greatly enhanced over extended periods compared to antisense alone, while at the same time cellular cytotoxicity remains very low. In contrast, gene silencing is not enhanced with antisense polymer conjugates that are not able to self-assemble into micelles. Thus, using antisense precision micelles, we are able to achieve significant transfection and knockdown with minimal cytotoxicity at much lower concentrations of linear PEI then previously reported. Consequently, a conceptual solution to the problem of antisense or siRNA delivery is to self-assemble these molecules into 'gene-like' micelles with high local charge and increased stability, thus reducing the amount of transfection agent needed for effective gene silencing.

Reactions of (1) [Q]2[Fe4S4(SC(CH3)3)4] and the fluorous thiols HS(CH2)nRf8 (n = 2, 3; Rf8 = (CF2)7CF3)), or (2) [Na]2[Fe4S4(S(CH2)nRf8)4] (n = 2, 3) and [PhCH2P((CH2)3Rf6)3][Br] or [PPN][Cl] (PPN = Ph3P[horiz bar, triple dot above]N[horiz bar, triple dot above]PPh3), give the title compounds [Q]2[Fe4S4(S(CH2)nRf8)4], comprised of a fluorous dianion and in some cases fluorous cations, with (1) Q/n = Ph4P/2 (, 67%), Ph4P/3 (, 67%), Me4N/3 (69%), and Ph3P(CH2)2Rf6/2 (73%) or (2) PhCH2P((CH2)3Rf6)3/2 (, 39%), PhCH2P((CH2)3Rf6)3/3 (, 63%), and PPN/2 (36%). The educt [Ph3P(CH2)2Rf6]2[Fe4S4(SC(CH3)3)4] is in turn prepared from FeCl3, HSC(CH3)3/CH3ONa, and [Ph3P(CH2)2Rf6][I], and the educts [Na]2[Fe4S4(S(CH2)nRf8)4] from [Na]2[Fe4S4(SC(CH3)3)4] and HS(CH2)nRf8. The SCH2(1)H and (13)C NMR signals of these paramagnetic salts appear 8.7-10.3 and 32.3-34.9 ppm downfield from those of the corresponding thiols, but the chemical shifts of other signals are nearly normal. The UV-visible spectra show bands similar to those of non-fluorous analogs (290-298 nm and 406-415 nm; ε = 25 700 and 19 200 M(-1) cm(-1) for ). The singly fluorous salts are soluble in organic solvents of moderate polarity, but not in fluorous solvents. The doubly fluorous salts , are soluble in all fluorous solvents assayed, with partition coefficients of >99.65 : <0.35 (CF3C6F11/toluene) and 93.2-93.1 : 6.9-6.8 (FC-72/THF). Cyclic voltammograms carried out using a platinum working microelectrode show that is 0.08 V thermodynamically easier to reduce than .

With metal-based catalysts, it is quite common that a ligand (L) must first dissociate from a catalyst precursor (L'n M-L) to activate the catalyst. The resulting coordinatively unsaturated active species (L'n M) can either back react with the ligand in a k-1 step, or combine with the substrate in a k2 step. When dissociation is not rate determining and k-1 [L] is greater than or comparable to k2 [substrate], this slows the rate of reaction. By introducing a phase label onto the ligand L and providing a suitable orthogonal liquid or solid phase, dramatic rate accelerations can be achieved. This phenomenon is termed "phase-transfer activation". In this Concept, some historical antecedents are reviewed, followed by successful applications involving fluorous/organic and aqueous/organic liquid/liquid biphasic catalysis, and liquid/solid biphasic catalysis. Variants that include a chemical trap for the phase-labeled ligands are also described., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The nickel salicylaldiminato phosphine complexes [1,2,3-C6H3(9-anthracenyl)O(CH═N(2,6-C6H3(iPr)2)]Ni(Me)[P(4-C6H4R)3] (4; R = a, (CH2)2Rf8; b, (CH2)3Rf8; c, H (Rf8 = (CF2)7CF3)) are prepared from the corresponding phosphines 3a-c and nickel NCMe adduct (46-68%). These are applied as catalysts for ethylene polymerization in toluene and fluorous/toluene liquid/liquid biphasic mixtures. Under the latter conditions, the fluorous phosphines 3a,b that must dissociate to generate the active catalyst migrate to the fluorous phase (partition coefficients 97.5:2.5 and 66.6:33.4 vs <0.5:>99.5 for 4a,b). Catalysts 4a,b show marked accelerations under biphasic conditions, but 4c (which has a lipophilic phosphine ligand) does not. Under all conditions, 4a,b are faster catalysts than the Ni(Ph)(PPh3) analogue, a previously reported benchmark.

The solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 4-methylpiperidine (4MP) with the σ-electron acceptor iodine and π-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) have been investigated spectrophotometrically in chloroform at 25 °C. These were characterized through electronic and infrared spectra as well as elemental and thermal analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(4MP) I](+)I(-)3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)] and with TCNQ the adduct [TCMPQDM] is obtained through N-substitution reaction in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT, molar extinction coefficient εCT, free energy change ΔG(0), CT energy ECT and the ionization potential Ip have been calculated for the CT-complexes [(4MP) I](+)I(-)3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)]., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A series of light- and air-stable silver(I) pyrazolylmethylpyridine complexes [Ag(L(R))]n(BF4)n (L = pyrazolylmethylpyridine; R = H, 1; R = Me, 2; R = i-Pr, 3) and [Ag(L(R))(NO3)]2 (L = pyrazolylmethylpyridine; R = H, 4; R = Me, 5; R = i-Pr, 6) has been synthesized and structurally and spectroscopically characterized. In all of the molecular structures, the pyrazolylmethylpyridine ligands bridge two metal centers, thus giving rise to dinuclear (2, 4, 5, and 6) or polynuclear structures (1 and 3). The role played by the counteranions is also of relevance, because dimeric structures are invariably obtained with NO3(-) (4, 5, and 6), whereas the less-coordinating BF4(-) counteranion affords polymeric structures (1 and 3). Also, through atoms-in-molecules (AIM) analysis of the electron density, an argentophilic Ag···Ag interaction is found in complexes 2 and 4. Thermogravimetric analysis (TGA) shows that the thermolytic properties of the present complexes can be significantly modified by altering the ligand structure and counteranion. These complexes were further investigated as thin silver film precursors by spin-coating solutions, followed by annealing at 310 °C on 52100 steel substrates. The resulting polycrystalline cubic-phase Ag films of ∼55 nm thickness exhibit low levels of extraneous element contamination by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that film growth proceeds primarily via an island growth (Volmer-Weber) mechanism. Complex 4 was also evaluated as a lubricant additive in ball-on-disk tribological tests. The results of the friction evaluation and wear measurements indicate a significant reduction in wear (∼ 88%) at optimized Ag complex concentrations with little change in friction. The enhanced wear performance is attributed to facile shearing of Ag metal in the contact region, resulting from thermolysis of the silver complexes, and is confirmed by energy-dispersive X-ray analysis of the resulting wear scars.

Polyisobutylene (PIB)-bound ruthenium bipyridine [Ru(PIB-bpy) 3 ] 2+ metal complexes were prepared from PIB ligands formed by alkylation of 4,4'-dimethylbipyridine with polyisobutylene bromide. The product Ru(PIB-bpy) 3 Cl 2 complexes with at least one PIB ligand per bipyridine unit function as soluble recyclable photoredox catalysts in free radical polymerization of acrylate monomers under visible light irradiation at 25 °C with ethyl 2-bromoisobutyrate as the initiator in the presence of diisopropylethylamine. The polyacrylate products contained only about 1 ppm Ru contamination. This PIB-bound catalyst was recyclable and showed about 50-fold less Ru leaching as compared to Ru leaching in a polymerization catalyzed by the low molecular weight Ru catalyst, Ru(bpy) 3 (PF 6 ) 2 .

A fluorous phosphine analogue of Grubbs' second generation olefin metathesis catalyst, (H(2)IMes)((R(f8)(CH(2))(2))(3)P)(Cl)(2)Ru(=CHPh) (1; H(2)IMes/R(f8) = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene/(CF(2))(7)CF(3)) is crystallized and the X-ray structure analyzed in detail. The bond lengths and angles about ruthenium are compared to those of two solvates and five derivatives of Grubbs' second generation catalyst. All exhibit distorted square pyramidal geometries in which the alkylidene ligands occupy apical positions, and geometric trends are interpreted with the help of density functional calculations. The perfluoroalkyl groups (1) exhibit helical conformations, as manifested by various torsional relationships, (2) segregate in the lattice, and (3) align in pairs of opposite helical chiralities.

Luminescent polymers containing Ir(ppy) 2 (bpy) PF 6 complexes, biocompatible poly(ethylene glycol) (PEG) chains, and biotin moieties were synthesized via ring-opening metathesis polymerization (ROMP). Their self-assembly in water into micelles resulted in an increased quantum yield compared to open polymer chains in acetonitrile, which is likely due to core rigidity and desolvation. Streptavidin coated magnetic beads were employed to analyze the binding ability of these micelles. The positioning of the molecular recognition moiety biotin within the polymer chain had a very significant effect on the availability of biotin on the micelle surface and the ability of the micelles to bind to streptavidin. Simply attaching biotin to the end of the ROMP polymer yielded micelles in which the biotin units were shielded by the PEG chains, whereas the synthesis of a new ROMP monomer containing biotin at the end of the PEG chains resulted in improved surface availability of the biotin group. Preliminary experiments in which streptavidin was microcontact-printed onto functionalized glass coverslips also indicated specific binding between the micelles and streptavidin and further demonstrated the potential of these micelle systems to function as luminescent probes in solid-phase biodetection assays.

Here, we introduce a 3D-DNA construction method that assembles a minimum number of DNA strands in quantitative yield, to give a scaffold with a large number of single-stranded arms. This DNA frame is used as a core structure to organize other functional materials in 3D as the shell. We use the ring-opening metathesis polymerization (ROMP) to generate block copolymers that are covalently attached to DNA strands. Site-specific hybridization of these DNA-polymer chains on the single-stranded arms of the 3D-DNA scaffold gives efficient access to DNA-block copolymer cages. These biohybrid cages possess polymer chains that are programmably positioned in three dimensions on a DNA core and display increased nuclease resistance as compared to unfunctionalized DNA cages., (© 2012 American Chemical Society)

Analogs of Grubbs' second generation catalyst with hydrophilic phosphine ligands are synthesized, and those with Cy(2)PCH(2)CH(2)N(CH(3))(3)(+) Cl(-) and Cy(2)PCHCH(2)CH(2)N(CH(3))(2)(+)CH(2)CH(2) Cl(-) give much faster ring closing metatheses under CH(2)Cl(2)/aqueous or CH(2)Cl(2)/aqueous HCl biphasic as opposed to CH(2)Cl(2) monophasic conditions. This is attributed to rapid phase transfer of the dissociated ligand to the aqueous phase, where under acidic conditions it is protonated.

The spectrophotometric characteristics of the solid charge-transfer molecular complexes (CT) formed in the reaction of the electron donors imidazole (IML) and 1-benzylimidazole (BIML) with the σ-acceptor iodine and π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetracyanoethylene (TCNE) and 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL) have been studied in chloroform at 25 °C. These were investigated through electronic and infrared spectra as well as elemental analysis. The results show that the formed solid CT-complexes have the formulas [(IML)2 I]I3, [(IML)(DDQ)], [(IML)2(TCNE)5] and [(IML)(CHL)] for imidazole and [(BIML) I]I3, [(BIML)(DDQ)2], [(BIML)(TCNE)2] and [(BIML)(CHL)2] for 1-benzylimidazole in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT, molar extinction coefficient ɛCT, free energy change ΔG0, CT energy ECT and ionization potential Ip have been calculated for the CT-complexes [(IML)2 I]I3, [(IML)(DDQ)], [(IML)(CHL)], [(BIML) I]I3, [(BIML)(DDQ)2], [(BIML)(TCNE)2] and [(BIML)(CHL)2]., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The preparation of polyethylene-oligomer (PE(olig))-supported N-heterocyclic carbene ligands (NHCs) and their Ru complexes is described. These complexes are structurally analogous to their low molecular weight counterparts and can serve as thermomorphic, recoverable/recyclable ring-closing metathesis (RCM) catalysts. Because of the insolubility of PE(olig)-supported species at 25 °C, such complexes can perform homogeneous RCM reactions at 65 °C and, upon cooling, precipitate as solids. This allows for their quantitative separation from solutions of products., (© 2011 American Chemical Society)

The reactions of the electron donor 1-methylpiperidine (1MP) with the pi-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil=CHL) and iodine (I(2)) were studied spectrophotometrically in chloroform at room temperature. The electronic and infrared spectra of the formed molecular charge-transfer (CT) complexes were recorded. The obtained results showed that the stoichiometries of the reactions are not fixed and depend on the nature of the acceptor. Based on the obtained data, the formed charge-transfer complexes were formulated as [(1MP)(TCNE)(2)], [(1MP)(DDQ)].H(2)O, [(1MP)(CHL)] and [(1MP)I]I(3), while in the case of 1MP-TCNQ reaction, a short-lived CT complex is formed followed by rapid N-substitution by TCNQ forming the final reaction products 7,7,8-tricyano-8-piperidinylquinodimethane (TCPQDM). The five solids products were isolated and have been characterized by electronic spectra, infrared spectra, elemental analysis and thermal analysis., (Copyright 2009 Elsevier B.V. All rights reserved.)

The interactions of the electron donors 2-aminopyridine (2APY) and 3-aminopyridine (3APY) with the pi-acceptors tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), 2-chloro-1,3,5-trinitrobenzene (picryl chloride, PC), and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) were studied spectrophotometrically in chloroform at room temperature. The electronic and infrared spectra of the formed molecular charge transfer (CT) complexes were recorded. Photometric titration showed that the stoichiometries of the reactions were fixed and depended on the nature of both the donor and the acceptor. The molecular structures of the CT-complexes were, however, independent of the position of the amino group on the pyridine ring and were formulated as [(APY)(TCNE)], [(APY)(DDQ)], [(APY)(PC)], and [(APY) (chloranil)]. The formation constants (K(CT)), charge transfer energy (E(CT)) and molar extinction coefficients (epsilon(CT)) of the formed CT-complexes were obtained.

The synthesis of polyisobutylene (PIB)-supported N-heterocyclic carbenes (NHCs) that are useful as ligands for recoverable/recyclable organometallic complexes is described. Both PIB-bound carbenes analogous to SIMes and IMes as well as carbene precursors bound to PIB via 1,2,3-triazoles by alkyne-azide couplings are described. Both Ag(I) and Ru(II) complexes of these carbenes are shown to be phase selectively soluble in heptane. Hoveyda-Grubbs second-generation catalysts containing a PIB-supported NHC have also been used to catalyze ring-closing metathesis.

The solid charge-transfer complexes formed in the reaction of the electron donor 1,4,7-trimethyl-1,4,7-triazacyclononane (TMTACN) with the acceptors iodine, tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) have been isolated. These were characterized through electronic and infrared spectra as well as thermal and elemental analysis. The results show that the formed solid CT-complexes have the formulas [(TMTACN)I]I3, [(TMTACN)(TCNE)5] and [(TMTACN)(TCNQ)3] in full agreement with the known reaction stoichiometries in solution. The chloranil CT-solid complex cannot be isolated in pure form.

Terminally vinyl-functionalized polyisobutylene (PIB) oligomers can be easily transformed into end-functionalized PIB-bound Ru metathesis catalysts. The nonpolar catalysts so prepared can be used as solutions in heptane and recycled by a gravity-based extraction after addition of a heptane-immiscible polar solvent. This paper describes the synthesis and the recycling of a PIB-supported second-generation Hoveyda-Grubbs catalyst for Ru-catalyzed ring-closing metathesis and ring-opening metathesis polymerizations.

Ring-opening metathesis polymerization was used to generate an ABC triblock copolymer, containing complementary diamidopyridine (DAP) and thymine (THY) outer blocks, which assembles into spherical aggregates held together by DAP-THY noncovalent interactions. Addition of THY-containing small guest molecules results in complete opening and deaggregation of the block copolymer micelle. This molecular recognition and macroscopic response shows high selectivity to the guest structure, and tolerates only a small amount of conformational mobility in the THY guest. On the other hand, addition of a small DAP-containing guest does not break the aggregates, but instead, results in new micelles which show a different selectivity profile from the parent morphology. We have examined the effect of a number of structural features in the block copolymers, on both the extent and selectivity of their macroscopic response to guests (that is, opening of the micelle). This study has resulted in a set of structural guidelines, which help in the design of effective molecule-responsive micelles for applications in selective drug delivery, sensing, and surface patterning.

Quantum dots (QDs) are emerging as alternative or complementary tools to the organic fluorescent dyes currently used in bioimaging. QDs hold several advantages over conventional fluorescent dyes including greater photostability and a wider range of excitation/emission wavelengths. However, recent work suggests that QDs exert deleterious effects on cellular processes. This study examined the subcellular localization and toxicity of cadmium telluride (CdTe) QDs and pharmacological means of preventing QD-induced cell death. The localization of CdTe QDs was found to depend upon QD size. CdTe QDs exhibited marked cytotoxicity in PC12 and N9 cells at concentrations as low as 10 microg/ml in chronic treatment paradigms. QD-induced cell death was characterized by chromatin condensation and membrane blebbing and was more pronounced with small (2r=2.2+/-0.1 nm), green emitting positively charged QDs than large (2r=5.2+/-0.1 nm), equally charged red emitting QDs. Pretreatment of cells with the antioxidant N-acetylcysteine and with bovine serum albumin, but not Trolox, significantly reduced the QD-induced cell death. These findings suggest that the size of QDs contributes to their subcellular distribution and that drugs can alter QD-induced cytotoxicity.

The synthesis, X-ray structure, and electrochemical and photophysical characterization of [Ru(phen)(2)dpq-n][PF(6)](2) (phen = phenanthroline, dpq-n = dipyridoquinoxaline-norbornene) are described. This complex contains a Ru(phen)(3)(2+) moiety in close conjugation with a norbornene unit and is the first example of a Ru(II) diimine complex capable of undergoing ring-opening metathesis polymerization. Luminescence studies of this complex showed an increase in quantum efficiency in polar solvents and in water. Preliminary ring-opening metathesis polymerization studies, carried out at low monomer-to-initiator ratio, showed the formation of an oligomeric mixture composed mainly of the dimer of this complex. This dimer exhibits photophysical and redox properties similar to those of the monomer, indicating that the Ru(phen)(3)(2+) moiety remains intact during the polymerization.