We report on a new class of thermoresponsive biodegradable polyesters (TR-PE) inspired by polyacrylamides and elastin-like proteins (ELPs). The polyesters display reversible phase transition with tunable cloud point temperatures (T cp ) in aqueous solution as evidenced by UV−vis spectroscopy, 1 H NMR, and DLS measurements. These polyesters form coacervate droplets above their lower critical solution temperature (LCST). The T cp of the polyesters is influenced by the solutes such as urea, SDS, and NaCl. The T cp of the copolymers shows a linear correlation with the composition of the polyesters indicating the ability to tune the phase change temperature. We also show that such thermoresponsive coacervates are capable of encapsulating small molecules such as Nile Red. Furthermore, the polyesters are hydrolytically degradable.

The precise guidance to different ions across the biological channels is essential for many biological processes. An artificial nanopore system will facilitate the study of the ion-transport mechanism through nanosized channels and offer new views for designing nanodevices. Herein we reveal that a 2.5 nm-sized, fullerene-shaped molecular cluster Li48+m K12(OH)m [UO2(O2)(OH)]60-(H2O)n (m ≈ 20 and n ≈ 310) (U60) shows selective permeability to different alkali ions. The subnanometer pores on the water-ligand-rich surface of U60 are able to block Rb(+) and Cs(+) ions from passing through, while allowing Na(+) and K(+) ions, which possess larger hydrated sizes, to enter the interior space of U60. An interestingly high entropy gain during the binding process between U60 and alkali ions suggests that the hydration shells of Na(+)/K(+) and U60 are damaged during the interaction. The ion selectivity of U60 is greatly influenced by both the morphologies of the surface nanopores and the dynamics of the hydration shells.

The research on chiral recognition and chiral selection is not only fundamental in resolving the puzzle of homochirality, but also instructive in chiral separation and stereoselective catalysis. Here we report the chiral recognition and chiral selection during the self-assembly process of two enantiomeric wheel-shaped macroanions, [Fe 28 The enantiomers are observed to remain self-sorted and self-assemble into their individual assemblies in their racemic mixture solution. The addition of chiral co-anions can selectively suppress the self-assembly process of the enantiomeric macroanions, which is further used to separate the two enantiomers from their mixtures on the basis of the size difference between the monomers and the assemblies. We believe that delicate long-range electrostatic interactions could be responsible for such high-level chiral recognition and selection.

The symmetry, structure and formation mechanism of the structurally self-complementary {Pd84} = [Pd84O42(PO4)42(CH3CO2)28](70-) wheel is explored. Not only does the symmetry give rise to a non-closest packed structure, the mechanism of the wheel formation is proposed to depend on the delicate balance between reaction conditions. We achieve the resolution of gigantic polyoxopalladate species through electrophoresis and size-exclusion chromatography, the latter has been used in conjunction with electrospray mass spectrometry to probe the formation of the ring, which was found to proceed by the stepwise aggregation of {Pd6}(-) = [Pd6O4(CH3CO2)2(PO4)3Na(6-n)H(n)](-) building blocks. Furthermore, the higher-order assembly of these clusters into hollow blackberry structures of around 50 nm has been observed using dynamic and static light scattering.

An inorganic-organic hybrid surfactant with a hexavanadate cluster as the polar head group was designed and observed to assemble into micelle structures, which further spontaneously coagulate into a 1D anisotropic structure in aqueous solutions. Such a hierarchical self-assembly process is driven by the cooperation of varied noncovalent interactions, including hydrophobic, electrostatic, and hydrogen-bonding interactions. The hydrophobic interaction drives the quick formation of the micelle structure; electrostatic interactions involving counterions leads to the further coagulation of the micelles into larger assemblies. This process is similar to the crystallization process, but the specific counterions and the directional hydrogen bonding lead to the 1D growth of the final assemblies. Since most of the hexavanadates are exposed to the surface, the 1D assembly with nanoscale thickness is a highly efficient heterogeneous catalyst for the oxidation of organic sulfides with appreciable recyclability.

The Schulze-Hardy rule is a well-established observation in colloid science (can be derived from the DLVO theory) that demonstrates the relationship between the critical coagulation concentration (CCC) of colloids and the valence of extra counterionic electrolytes (z), with a simple mathematical relationship of CCC≈z . Here the Schulze-Hardy Rule is expanded to much smaller, nano-scaled soluble macroions in aqueous solution, by examining the stability of the macroions in the presence of additional electrolytes. The CCC values of the macroions follow the general trend of CCC≈z but the n value is significantly dependent on the surface charge density of the macroions, ranging from n=2 at very low surface charge density to n=6 at a high surface charge density. In addition, different cations with the same valence showed clear different impacts on the CCC values, with an interesting trend being connected to the Hofmeister series originally discovered in protein solutions.

POM and circumstance: Nanometer-sized polyoxometalates (POMs) bring a new direction to anion-templated supramolecular chemistry. The Keggin (left) and Dawson-type (right) polyoxoanions direct the assembly of giant metallomacrocycles through an array of weak hydrogen-bonding interactions. The concerted action of multiple hydrogen bonds keeps the templating guests embedded within the hosts, even in the solution state.

Three types of macroanion-countercation interactions in dilute solution, decided by the strength of electrostatic attraction and the change of hydration shells are reported: minor interaction between macroanions [MO Pd (SeO ) ] (M=Zn or Ni ) and monovalent cations (Na , K , Rb , Cs ), leaving their hydration shells intact (solvent-separated ion-pairs); strong binding between macroanions and divalent cations (Sr , Ba ) to form solvent-shared ion-pairs with partial dehydration; very strong electrostatic attraction between macroanions and Y ion with contact ion-pairs formation by severely breaking their original hydration shells and forming new ones. In addition, divalent cations can help the macroanions self-assemble into hollow spherical blackberry structures through counterion-mediated attraction, whereas macroanions with mono- or trivalent cations only stay as discrete ions due to either weak interaction or a small number of bound countercations.