Decking out dendrimers: Peptide-decorated dendrimers (PDDs), a class of spherical polymers with peptides covalently attached to their surface, have found application in imaging and drug development. In addition to selected bioapplications, this Minireview also summarizes the development of PDD synthetic routes that employ diverse conjugation chemistry. Green ball=peptide; blue structure=dendrimer scaffold.

The selective and predictable synthesis of structurally uniform carbon nanotubes (CNTs) represents a long-standing goal in both nanocarbon science and synthetic organic chemistry. This Review focuses on the studies toward controlled synthesis of CNTs with single chirality through the organic synthesis of CNT segments and the organic template-assisted growth of CNTs.

Organized titanium clusters: The labile coordination sites of a robust {Ti₆} cluster have been used to functionalize the surface of the {Ti₆} cluster with organic species and transition-metal ions (see picture). A bandgap engineering study indicates that both the electron-withdrawing effect of the organic ligands and the coordination environments of the incorporated metal ions tune the bandgap structures of the titanium–oxo clusters.

The journey matters: Self-propelled particles are induced to assemble into different chiral structures that rotate persistently in an electric field. Rather than energy preference, dynamic factors during the non-equilibrium assembly determine which structure is selected.

Dig this! Cyclization of silylenolether-ynesulfonamides proceeds at ambient temperature under mild reaction conditions under silver catalysis. Bridged compounds were obtained exclusively through 7-exo-dig reactions. The protocol is applicable to a wide range of substrates, thus leading to azabicyclic frameworks.

QM/MM simulations were conducted to assign a specific molecular structure to the intermediate formed in the electron-induced repair of (6-4) photolesions (purple) detected previously in ultrafast transient absorption spectroscopy. The repair mechanism involves proton transfer from the protonated His365 to the N3′ nitrogen of the lesion along an oxetane-like transition state.

Buckle up! A cell-like colloidosome composed of self-oscillating microgels that exhibits drastic shape oscillations in addition to swelling/deswelling oscillations was fabricated. The resulting oscillatory profile waveform became markedly more complex than a conventional one. Multiple buckling points were observed for larger colloidosomes, analogous to cell behavior.

In quite a state: A neutral mononuclear Fe^III complex [Fe^III(H-5-Br-thsa-Me)(5-Br-thsa-Me)]⋅H₂O (thsa=5-bromosalicylaldehyde methylthiosemicarbazone) exhibited a three-step spin crossover with symmetry breaking and a 14 K hysteresis loop owing to strong cooperativity (see picture). The intermediate spin states showed remarkable long-range 4 HS–2 LS and 2 HS–4 LS spin-state ordering (HS=high-spin, red; LS=low-spin, green).

Alcohol can H⋅⋅⋅elp: Water, methanol, or ethanol triggered the formation of a [N₂O₂]-bridged intermediate from a reduced cobalt–nitrosyl N-confused porphyrin to enable the conversion of NO into N₂O (see scheme). Hydrogen-bonding interactions assisted N−N coupling and N−O bond cleavage in the intermediate to generate N₂O.

Phase transitions: The glassy state of a two-dimensional (2D) Cd²⁺ coordination polymer crystal was prepared by a solvent-free mechanical milling process. The coordination polymer shows an increased proton conductivity and an increased dielectric constant in the glassy state (see picture).

Direct conductivity measurement of an electrodeposited Li₂O₂ film and an in situ SERS study on the O₂ reduction reaction (ORR) using ¹⁸O₂ for passivation and ¹⁶O₂ for further discharging unveiled the origin of sudden death of aprotic Li-O₂ batteries. Both ORR and O₂ evolution (OER) occur at the buried interface of cathode|Li₂O₂, and thus the Li-O₂ electrochemistry is limited by electron transport instead of Li⁺ and O₂ transport.

Molecular packing motifs play a key role in determining the charge-transport properties of molecular materials. Interlayer electronic couplings perpendicular to the current direction result in a drastic decrease of charge mobilities, shown by utilizing field-effect transistors. α-Phase TiOPc crystals (see picture; left) show a maximum mobility μ_max more than 250 times that of the β-phase.

The gains in catalytic activity that are achievable through bifunctional coupling by diffusion (between two sites s and t; see picture) are assessed using generic reaction schemes and a descriptor-based approach. The analysis predicts that only the coupling of different classes of materials, such as metals and oxides, can give rise to substantial gains.

“Watch” and learn: Combined high-resolution fluorescence detection X-ray absorption near-edge spectroscopy (HERFD-XANES), X-ray diffraction (XRD), and X-ray emission spectroscopy under real operando conditions provided detailed insight into the nature of the Mo species on zeolite ZSM-5 during methane dehydroaromatization, demonstrating the importance in controlling Mo speciation to influence selectivity towards light olefins and/or aromatic species.

Using upconversion luminescent nanoparticles (UNPs) as a polychromatic emission donor, a single-excited duplexed luminescence resonance energy transfer (D-LRET) system was developed on a cell surface for in situ duplexed imaging and relative quantification of two kinds of sugars on a specific protein using mucin 1 (MUC1) as the model. The strategy also enables monitoring of the expression of the fucosylated and sialylated terminal on MUC1.

Anticancer mineralization: Cancer-cell-targeting calcification can convert tumors into calcified tissues by using folic acid (FA), calcium, and the folate receptor (FR) resulting in cancer cell growth and metastatic inhibition without any drugs. These results suggest cancer cells can be selectively targeted using biomineralization methods.

Split the difference: A series of 6,13-bis(triisopropylsilylethynyl)pentacene–alkanethiolate monolayer protected gold nanoparticles with different particle sizes and alkane chain lengths were synthesized. These systems were employed for the efficient generation of excited triplet states on the pentacene molecules by using singlet exciton fission to suppress energy transfer to the Au surface.

A new strategy enables accurate quantum-mechanical ab initio predictions for the methylation of small alkenes over zeolite catalysts. The calculated reaction rate constants (free energies), pre-exponential factors (entropies), and enthalpy barriers show that this computational strategy yields results that agree with experiment within chemical accuracy limits.

A ferrimagnetic order lattice has been artificially constructed by electron doping by lithium ion insertion from a magnetically disordered ground state in a neutral donor/acceptor metal–organic framework (D/A-MOF). The stability of the magnetically ordered lattice depends on the equilibrium potential of the D/A-MOF cathode. The results suggest a new strategy and direction for the design of molecule-based magnets.

A flexible solar cell that can be excited by sunlight and raindrops is presented. The solar-to-electric conversion efficiency is created by complicated photoelectrochemical reactions, while electric signals, produced by dropping raindrops on rGO film, arise from π-electron|cation pseudocapacitance at the rGO/raindrop interface. This work could guide the design of all-weather solar cells.

A nickel(II) complex [Ni(L)₂Cl]Cl (L= 6-((diphenylphosphino)methyl)pyridin-2-amine), having an amine base as a proton-transfer site, was synthesized and used as a hydrogen-production catalyst. Electrochemical measurements with the complex show that a higher rate of H₂ production (turnover frequency=8400 s⁻¹) can be achieved under weak acid conditions using acetic acid as a proton source.

The redox-controlled block copolymerization of cyclohexene oxide and lactide capitalizes on the ability for a bis(imino)pyridine iron bisalkoxide complex to polymerize lactide in the iron(II) oxidation state and epoxide in the iron(III) state, but not vice versa. Diblock copolymers were synthesized with both monomers present starting with either the iron(II) or iron(III) catalyst and using an in situ redox switch.

NTP drugs go pro: The TriPPPro-approach was used to synthesize a series of nucleoside triphosphate analogues. The TriPPPro-compounds displayed anti-HIV activity and cellular uptake. In some cases, even inactive parent nucleosides were converted into powerful antiviral compounds. These results could thus aid the development of future nucleoside prodrugs.

A complex delicacy: Arsenic-containing phosphatidylcholines and an arsenic-containing phosphatidylethanolamine have been identified in fish roe. The incorporation of the arsenic group into typical membrane lipids might impart particular properties to the molecules not displayed by their non-arsenic analogues.

Stereocontrol is on: A single-site supported organozirconium catalyst exhibits unprecedented all-cis stereo/face-selective hydrogenation of substituted alkylarenes under mild reaction conditions. The resulting stereopure cycloalkanes offer new building blocks for value-added fine chemicals.

Double dose of iron: The titled redox-neutral [4+2] annulations to furnish cis-3,4-dihydroisoquinolines were achieved by using iron catalysis. Mechanistic studies show the synergy of dinuclear iron in the C−H bond activation and turnover-limiting hydrogen-transfer steps. The reaction demonstrates excellent atom economy and exclusive cis stereoselectivity.

A jab-cross move: A heterogeneously catalyzed oxidative dehydrogenative cross-coupling of aryl amines is reported. Aryl amines were treated with various arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions to selectively afford cross-coupled products, and provides an efficient synthetic method for the preparation of nonsymmetrical biaryl amines by oxidative C−H activation.

Less is more: A highly efficient Co₃O₄-based electrocatalyst for the oxygen evolution reaction has been designed. The electrocatalyst, which features oxygen vacancies and a high surface area, was formed by an argon plasma-engraving strategy.

Ugi for real: Reaction of isonitriles (A) with 3-(arylamino)isobenzofuran-1(3H)-ones (B) in the presence of a catalytic amount of chiral phosphoric acid (CPA) afforded 3-oxo-2-arylisoindoline-1-carboxamides (C) in high yields with good to high enantioselectivities. An enantioselective Ugi multicomponent reaction of D, E, and A was subsequently developed for the synthesis of the same heterocycle C.

Active duty: Asymmetric alkynylation of isatins was achieved by a new bifunctional chiral guanidine ligand in combination with CuI under mild reaction conditions. Good levels of reactivity and excellent enantioselectivities were achieved with diverse alkyl- and aryl-substituted terminal alkynes and various substituted isatins, thus generating bioactive 3-alkynyl-3-hydroxyindolin-2-ones.

Give it a tri: Copper-catalyzed oxidative [1+1+1] cyclotrimerization of acetophenone derivatives under mild reaction conditions and with a broad reaction scope has been developed. This transformation is a radical cascade process that allows saturated carbocycles to be obtained by cyclotrimerization through functionalization of C(sp³)−H bonds.

Doubling up: A double dynamic kinetic resolution is described for the ansa-ruthenium(II)-catalyzed asymmetric transfer hydrogenation of diketones in formic acid/triethylamine to yield the title compounds, displaying a stereotriad, in excellent stereopurity. The intermediate mono-reduced alcohols were isolated in very high enantiopurity by using milder reaction conditions.

All about the DGs: A hydrazone-based exo-directing group (DG) strategy is developed for the functionalization of unactivated primary β C−H bonds of aliphatic amines. The hydrazone DGs can be conveniently installed and removed, and promote β-acetoxylation and tosyloxylation via a five-membered exo-palladacycle. PG=protecting group, Ts=4-toluenesulfonyl.

Go nuts! A novel triptycene-based chiral macrocyclic host with a hex-nut-like structure and highly fixed conformation was synthesized. Efficient resolution was achieved through the introduction of chiral auxiliaries to give a couple of enantiopure macrocycles, which exhibited highly enantioselective recognition of three pairs of chiral compounds containing a trimethylamino group.

Asymmetric reductive coupling of a ketone and an amine is a straightforward and atom-economic approach for preparing optically enriched amines. The highly efficient and direct asymmetric reductive amination of arylacetones, catalyzed by an iridium complex, supplies enantiomerically pure β-arylamines. The new phosphoramidite ligands reported show superb reactivity and enantioselectivity in this reductive coupling. M.S.=molecular sieves, TFA=trifluoroacetic acid.

From giver to taker: Incorporation of B←N units into polymer electron donors has resulted in a series of polymer electron acceptors. Extending the length of the repeating units of the conjugated polymers alleviates the effect of steric hindrance from the pendant groups and promotes the π–π stacking of the polymer backbones. The all-polymer solar-cell device shows a power conversion efficiency (PCE) exceeding 5.0 %.

The Binder Age: The organic binder in hybrid materials was used as a platform for grafting to preserve the high double-layer capacitance and the low ionic resistance of porous carbons. This binder allowed minimizing the loading of inactive material in the electrode, while improving its capacitance and reducing its ionic resistance, mainly owing to a better wettability of the porous carbon.

Continuum split: The isolation and systematic structural analysis of non-anchored indole–palladium(II) complexes revealed that there is a σ–π continuum for heteroarene–metal complexes. These findings may provide insights into key catalytic intermediates of metal-catalyzed heteroarene transformations.

Go with the flow: Using a flow microreactor system, carbamoyllithium compounds were successfully generated and used to react with electrophiles to give various amides, including α-ketoamides. The method was applied to the three-component synthesis of functionalized α-ketoamides using a carbamoyllithium compound, methyl chloroformate, and a functionalized organolithium reagent. PMB=p-methoxybenzyl; FG=functional group.

Versatile conjunctive reagents: New conjunctive β-silylated organometallic reagents of Li, Mg, and Zn have been prepared and used for an expeditive construction of various polyfunctionalized 5-, 6-, and 7-membered heterocycles, such as furans, pyrroles, quinolines, benzo[b]thieno-[2,3-b]pyridine, naphthyridines, fused pyrazoles, and 2,3-dihydrobenzo[c]azepines.

Stop making sense: Selenocysteine is encoded by UGA, a stop codon reassigned by a Sec-specific elongation factor and a distinctive RNA structure. Analysis of 6.4 trillion base pairs of metagenomic sequences and about 25 000 genomes revealed tRNA^Sec species that recognize the stop codons UAG and UAA, and ten sense codons. Thus the genetic code is much more flexible than previously thought.

Chlorination of arenes with chloride anions: The photochemical analogue of the enzymatic chlorination of Flavin-adenine dinucleotide (FAD)-dependent halogenases is possible in the presence of riboflavin, air, acetic acid, and blue light (see scheme; RFT=riboflavin tetraacetate).