Observation of an Intermediate to H Binding in a Metal-Organic Framework.

Coordinatively unsaturated metal sites within certain zeolites and metal-organic frameworks can strongly adsorb a wide array of substrates. While many classical examples involve electron-poor metal cations that interact with adsorbates largely through physical interactions, unsaturated electron-rich metal centers housed within porous frameworks can often chemisorb guests amenable to redox activity or covalent bond formation. Despite the promise that materials bearing such sites hold in addressing myriad challenges in gas separations and storage, very few studies have directly interrogated mechanisms of chemisorption at open metal sites within porous frameworks.

Red-emitting KHFWOF:Mn for application in warm-white phosphor-converted LEDs - optical properties and magnetic resonance characterization.

We report novel efficient Mn4+ phosphors of composition K3HF2MO2F4:Mn4+ (M = Mo, W) containing [HF2]- and octahedral [MO2F4]2- building units. The phosphor exhibits strong absorption at 450 nm and an external quantum yield of 90%. K3HF2WO2F4:0.

Recoupling dipolar interactions with multiple I=1 quadrupolar nuclei: A B{Li} and P{Li} rotational echo double resonance study of lithium borophosphate glasses.

The case of rotational echo double resonance (REDOR) experiments on the observe nuclei B and P interacting with multiple I=1 quadrupolar nuclei is analyzed in detail by SIMPSON simulations and experimental studies. The simulations define the region within the parameter space spanned by nutation frequency, quadrupolar coupling constant and spinning frequency where the parabolic analysis of the initial REDOR curve in terms of dipolar second moments has validity. The predictions are tested by experimental studies on the crystalline model compounds lithium diborate and lithium pyrophosphate, which are subsequently extended to measure dipolar second moments M(B{Li}) and M(P{Li}) in three borophosphate glasses.