Brian Newell

Rare-earth nitrides are an exciting family of materials with a wide variety of properties desirable for new physics and applications in spintronics and superconducting devices. Among them, samarium nitride is an interesting compound reported to have ferromagnetic behavior coupled with the potential existence of p-wave superconductivity. Synthesis of high-quality thin films is essential in order to manifest these behaviors and understand the impact that vacancies, structural distortions, and doping can have on these properties. In this study, we report the synthesis of samarium nitride monocrystalline thin films on magnesium oxide (001) substrates with a chromium nitride capping layer using molecular beam epitaxy (MBE). We observed a high-quality monocrystalline SmN film with matching orientation to the substrate, then optimized the growth temperature. Despite the initial 2 nm of growth showing formation of a potential samarium oxide layer, the subsequent layers showed high-quality SmN, with semiconducting behavior revealed by an increase in resistivity with decreasing temperature. These promising results highlight the importance of studying diverse heteroepitaxial schemes and open the door for integration of rare-earth nitrides and transition metal nitrides for future spintronic devices.

Phenochalcogenazines such as phenoxazines and phenothiazines have been widely employed as photoredox catalysts (PCs) in small molecule and polymer synthesis. However, the effect of the chalcogenide in these catalysts has not been fully investigated. In this work, a series of four phenochalcogenazines is synthesized to understand how the chalcogenide impacts catalyst properties and performance. Increasing the size of the chalcogenide is found to distort the PC structure, ultimately impacting the properties of each PC. For example, larger chalcogenides destabilize the PC radical cation, possibly resulting in catalyst degradation. In addition, PCs with larger chalcogenides experience increased reorganization during electron transfer, leading to slower electron transfer. Ultimately, catalyst performance is evaluated in organocatalyzed atom transfer radical polymerization and a photooxidation reaction for C(sp²)−N coupling. Results from these experiments highlight that a balance of PC properties is most beneficial for catalysis, including a long‐lived excited state, a stable radical cation, and a low reorganization energy.

Synthetic access to poly(indazolyl)methanes has limited their study despite their structural similarity to the highly investigated chelating poly(pyrazolyl)methanes and their potentially important indazole moiety. Herein is presented a high yielding, one-pot synthesis for the 3d-metal catalyzed formation of bis(1H-indazol-1-yl)methane from 1H-indazole utilizing dimethylsulfoxide as the methylene source. Complete characterization of bis(1H-indazol-1-yl)methane is given with 1H and 13C NMR, UV/Vis, FTIR, high resolution mass spectrometry and for the first time, single crystal X-ray diffraction. This simple, inexpensive pathway to yield exclusively bis(1H-indazol-1-yl)methane provides synthetic access to further investigate the coordination and potential applications of the family of bis(indazolyl)methanes.

Stabilized by multivalent CH–π and π–π interactions, metallocenes such as ferrocene and cobaltocenium can bind the cavity of [8]cycloparaphenylene to give highly conjugated, redox-switchable host–guest nanocarbons.

A temperature-induced structural phase transition is reported in layered hybrid perovskite (MA)₂PbI_2−xBr_x(SCN)₂ (0 ≤ x ≤ 1.2). The observed transition temperature decreases with Br substitution, suggesting a weakening of bonding interaction between the molecular ions.

A systematic study of four structurally-related hexacoordinate Co(ii) diimine complexes demonstrates links between ligand donor (σ/π) characteristics and slow magnetic dynamics and spin–lattice relaxation times.

Four series of brush block copolymers with near identical side chain compositions but varying backbone structures were synthesized to investigate the effect of backbone structure on the thermal self-assembly to photonic crystals.

We demonstrate a ferroelectric response in MAPbI ₃ single crystals that can modulate the electronic response and increase stability.

Jahn–Teller distortions are observed in Au₂₅(SR)₁₈ by single crystal X-ray crystallography. SQUID magnetometry, DFT theory, and linear optical spectroscopy corroborate the finding.