Humidity-modulated phase control and nanoscopic transport in supramolecular assemblies.

Supramolecular assembly allows for enhanced control of bulk material properties through the fine modulation of intermolecular interactions. We present a comprehensive study of a cross-linkable amphiphilic wedge molecule based on a sulfonated trialkoxybenzene with a sodium counterion that forms liquid crystalline (LC) phases with ionic nanochannel structures. This compound exhibits drastic structural changes as a function of relative humidity (RH).

Characterisation of different polymorphs of tris(8-hydroxyquinolinato)aluminium(III) using solid-state NMR and DFT calculations.

Background: Organic light emitting devices (OLED) are becoming important and characterisation of them, in terms of structure, charge distribution, and intermolecular interactions, is important. Tris(8-hydroxyquinolinato)-aluminium(III), known as Alq3, an organomettalic complex has become a reference material of great importance in OLED. It is important to elucidate the structural details of Alq3 in its various isomeric and solvated forms.

Supercycled homonuclear dipolar decoupling sequences in solid-state NMR.

We compare the performance of the windowed phase-modulated Lee-Goldburg (wPMLG) and the windowed decoupling using mind boggling optimisation (wDUMBO) sequences at various magic-angle spinning rates and nutation frequencies of the pulses. Additionally, we introduce a supercycled version of wDUMBO and compare its efficiency with that of the non-supercycled implementation of wDUMBO. The efficiency of the supercycled version of wPMLG, denoted wPMLG-S2, is compared with a new supercycled version of wPMLG that we notate as wPMLG-S3.

Sensitivity enhancement of the central-transition signal of half-integer spin quadrupolar nuclei in solid-state NMR: features of multiple fast amplitude-modulated pulse transfer.

Sensitivity enhancement of solid-state NMR spectrum of half-integer spin quadrupolar nuclei under both magic-angle spinning (MAS) and static cases has been demonstrated by transferring polarisation associated with satellite transitions to the central m=-1/2-->1/2 transition with suitably modulated radio-frequency pulse schemes. It has been shown that after the application of such enhancement schemes, there still remains polarisation in the satellite transitions that can be transferred to the central transition. This polarisation is available without having to wait for the spin system to return to thermal equilibrium.