Improving LMOF luminescence quantum yield through guest-mediated rigidification

Rotation of a specific pyridyl ring in LMOF-236 is locked by loading guest molecules into the MOF's pore, improving quantum yield by nearly 400%–an example of a generalizable strategy for maximizing quantum yield via guest-packing rigidification

A Convenient Synthetic Route to Partial-Cone p-Carboxylatocalix[4]arenes.

p-Carboxylatocalix[n]arenes have emerged as useful building blocks for the construction of a diverse range of supramolecular assemblies. A convenient route to a p-carboxylatocalix[4]arene that is locked in a partial-cone conformation is presented. The conformation gives the molecule markedly different topological directionality relative to those previously used in self- and metal-directed assembly studies

Electronic Tuning of Mixed Quinoidal‐Aromatic Conjugated Polyelectrolytes: Direct Ionic Substitution on Polymer Main‐Chains

The synthesis of conjugated polymers with ionic substituents directly bound to their main chain repeat units is a strategy for generating strongly electron-accepting conjugated polyelectrolytes, as demonstrated through the synthesis of a series of ionic azaquinodimethane (iAQM) compounds. The introduction of cationic substituents onto the quinoidal para-azaquinodimethane (AQM) core gives rise to a strongly electron-accepting building block, which can be employed in the synthesis of ionic small molecules and conjugated polyelectrolytes (CPEs). Electrochemical measurements alongside theoretical calculations indicate notably low-lying LUMO values for the iAQMs. The optical band gaps measured for these compounds are highly tunable based on structure, ranging from 2.30 eV in small molecules down to 1.22 eV in polymers. The iAQM small molecules and CPEs showcase the band gap reduction effects of combining the donor-acceptor strategy with the bond-length alternation reduction strategy. As a demonstration of their utility, the iAQM CPEs so generated were used as active agents in photothermal therapy

A hexahomotrioxacalix[3]arene-based ditopic receptor for alkylammonium ions controlled by Ag + ions 4

A receptor cone-1 based on a hexahomotrioxacalix[3]arene bearing three pyridyl groups 21 was successfully synthesized, which has a C3-symmetric conformation and is capable of binding 22 alkylammonium and metal ions simultaneously in a cooperative fashion. It can bind 23 alkylammonium ions through the -cavity formed by three aryl rings. This behaviour is consistent 24 with the cone-in/cone-out conformational rearrangement needed to reorganize the cavity for 25 endo-complexation. As a C3-symmetrical pyridyl-substituted calixarene, receptor cone-1 can also 26 bind a Ag + ion and the nitrogen atoms are turned towards the inside of the cavity and interact with 27 Ag +. After complexation of tris(2-pyridylamide) derivative receptor cone-1 with Ag + , the original 28 C3-symmetry was retained and higher complexation selectivity for n-BuNH3 + versus t-BuNH3 + was 29 observed. Thus, it is believed that this receptor will have a role to play in the sensing, detection, and 30 recognition of Ag + and n-BuNH3 + ions. 3

A supramolecular helicate with two independent Fe(II)switchable centres and a[Fe(anilate)3]3 guest

A biphenyl-spaced bis-pyrazolylpyridine ligand interacts with ferrous ions to engender a dimetallic helical coordination cage that encapsulates an Fe3+ tris-anilate complex. The host–guest interaction breaks the symmetry of the Fe2+ centers causing a differential spin crossover behavior in them that can be followed in great detail crystallographically.

Controlled Heterometallic Composition in Linear Trinuclear [LnCeLn] Lanthanide Molecular Assemblies.

The combination of two different β-diketone ligands facilitates the size-controlled assembly of pure heterometallic [LnLn'Ln] linear compounds thanks to two different coordination sites present in the molecular scaffold. [HoCeHo], [ErCeEr], and [YbCeYb] analogues are presented here and are characterized both in the solid state and in solution, demonstrating the selectivity of this unique method to produce heterometallic 4f molecular entities

A Most Unusual Zeolite Templating: Cage to Cage Connection of One Guest Molecule

An unusual case of a diquaternary ammonium dication, with large bulky end groups built from the tropane moiety and connected by a C4 methylene chain, is found to reside in zeolite SSZ-35 (STF). The structure of the guest/host product is such that the tropane bicylic entities reside in the shallow cavities of the cages of the STF structure and the C4 methylene chain runs through the 10-ring (~5.5 Å) window that connects the cages. This is a most unusual (and energy-intensive) templating of a zeolite structure with the guest molecule spanning two unit cells. The unusual result was found by single crystal studies with the addition of the use of the SQUEEZE program to show a consistent fit for the guest molecule following from measured electron densities in the crystal structure work. These analyses were followed with MAS NMR studies to confirm the integrity of the diquaternary guest molecule in the host sieve. A few comparative diquaternary guest molecules in MFI zeolite are also studied