Influence of Al2O3 Overlayers on Intermolecular Interactions between Metal Oxide Bound Molecules.

Intermolecular interactions on inorganic substrates can have a critical impact on the electrochemical and photophysical properties of the materials and subsequent performance in hybrid electronics. Critical to the intentional formation or inhibition of these processes is controlling interactions between molecules on a surface. In this report, we investigated the impact of surface loading and atomic-layer-deposited Al2O3 overlayers on the intermolecular interactions of a ZrO2-bound anthracene derivative as probed by the photophysical properties of the interface. While surface loading density had no impact on the absorption spectra of the films, there was an increase in excimer features with surface loading as observed by both emission and transient absorption. The addition of ALD overlayers of Al2O3 resulted in a decrease in excimer formation, but the emission and transient absorption spectra were still dominated by excimer features. These results suggest that ALD may provide a post-surface loading means of influencing such intermolecular interactions.

Molecular Sensitization Enabled High Performance Organic Metal Halide Hybrid Scintillator.

Scintillators, one of the essential components in medical imaging and security checking devices, rely heavily on rare-earth-containing inorganic materials. Here, a new type of organic-inorganic hybrid scintillators containing earth abundant elements that can be prepared via low-temperature processes is reported. With room temperature co-crystallization of an aggregation-induced emission (AIE) organic halide, 4-(4-(diphenylamino) phenyl)-1-(propyl)-pyrindin-1ium bromide (TPA-PBr), and a metal halide, zinc bromide (ZnBr2 ), a zero-dimensional (0D) organic metal halide hybrid (TPA-P)2 ZnBr4 with a yellowish-green emission peaked at 550 nm has been developed. In this hybrid material, dramatically enhanced X-ray scintillation of TPA-P+ is achieved via the sensitization by ZnBr4 2- . The absolute light yield (14,700 ± 800 Photons/MeV) of (TPA-P)2 ZnBr4 is found to be higher than that of anthracene (≈13,500 Photons/MeV), a well-known organic scintillator, while its X-ray absorption is comparable to those of inorganic scintillators. With TPA-P+ as an emitting center, short photoluminescence and radioluminescence decay lifetimes of 3.56 and 9.96 ns have been achieved. Taking the advantages of high X-ray absorption of metal halides and efficient radioluminescence with short decay lifetimes of organic cations, the material design paves a new pathway to address the issues of low X-ray absorption of organic scintillators and long decay lifetimes of inorganic scintillators simultaneously.

Tandem-trapped ion mobility spectrometry/mass spectrometry coupled with ultraviolet photodissociation.

RATIONALE: Tandem-ion mobility spectrometry/mass spectrometry methods have recently gained traction for the structural characterization of proteins and protein complexes. However, ion activation techniques currently coupled with tandem-ion mobility spectrometry/mass spectrometry methods are limited in their ability to characterize structures of proteins and protein complexes. METHODS: Here, we describe the coupling of the separation capabilities of tandem-trapped ion mobility spectrometry/mass spectrometry (tTIMS/MS) with the dissociation capabilities of ultraviolet photodissociation (UVPD) for protein structure analysis. RESULTS: We establish the feasibility of dissociating intact proteins by UV irradiation at 213 nm between the two TIMS devices in tTIMS/MS and at pressure conditions compatible with ion mobility spectrometry (2-3 mbar). We validate that the fragments produced by UVPD under these conditions result from a radical-based mechanism in accordance with prior literature on UVPD. The data suggest stabilization of fragment ions produced from UVPD by collisional cooling due to the elevated pressures used here ("UVnoD2"), which otherwise do not survive to detection. The data account for a sequence coverage for the protein ubiquitin comparable to recent reports, demonstrating the analytical utility of our instrument in mobility-separating fragment ions produced from UVPD. CONCLUSIONS: The data demonstrate that UVPD carried out at elevated pressures of 2-3 mbar yields extensive fragment ions rich in information about the protein and that their exhaustive analysis requires IMS separation post-UVPD. Therefore, because UVPD and tTIMS/MS each have been shown to be valuable techniques on their own merit in proteomics, our contribution here underscores the potential of combining tTIMS/MS with UVPD for structural proteomics.