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Aqueous anions play a crucial role in chemical and biological processes. They are traditionally classified as “structure makers” or “structure breakers” based on their impact on the viscosity of electrolyte solutions. Until now, this behavior has been assumed to stem from a single restructuring mechanism of the hydrogen (H) bonding network of water, that could align with macroscopic properties. Correlated Vibrational Spectroscopy (CVS) measurements reveal that this is not the case. Rather, anions modify water–water H-bonds through multiple distinct pathways, with frequency shifts correlating with charge transfer, and intensity changes quantifying variations in the number of interacting/orientationally cross-correlated H-bonds. The different ways through which anions impact water structure can be explained in terms of Hard–Soft-Acid–Base theory. Hard anions only affect water H-bonds through electrostatics. By contrast, soft anions weaken the H-bonds via charge transfer but simultaneously increase their concentration. The two effects for soft anions nearly cancel each other out in terms of structure breaking/making, resulting in macroscopic behavior that is similar to hard anions in spite of dramatically different molecular-level effects. 

Photocatalysis using complexes of d0 metals with ligand-to-metal charge-transfer (LMCT) excited states is an active area of research. Because titanium is the second most abundant transition metal in the earth’s crust, d0 complexes of TiIV are an appropriate target for this research. Recently, our group has demonstrated that the arylethynyltitanocene Cp2Ti(C2Ph)2CuBr is not emissive in room-temperature fluid solution, whereas the corresponding Cp* complex, Cp*2Ti(C2Ph)2CuBr, is emissive. The Cp* ligand is hypothesized to provide steric constraint that inhibits excited-state structural rearrangement. However, modifying the structure also changes the orbital character of the excited state. To investigate the impact of the excited-state orbital character on the photophysics, herein we characterize complexes similar to Cp*2Ti(C2Ph)2CuBr—but one with a more electron-rich arylethynyl ligand, ethynyldimethylaniline (C2DMA), and one with a more electron-poor arylethynyl ligand, ethynyl-α,α,α-trifluorotoluene. We have also prepared complexes with the C2DMA ligand but with different Cp ligands that adjust the steric bulk and constraint around the Ti, by replacing the Cp* ligands with either indenyl ligands or an ansa-cyclopentadienyl ligand where the two Cp ligands are bridged by a dimethylsilylene. All four target complexes have been characterized crystallographically and structure activity relationships are highlighted. 

This review was inspired by a January 2024 conference held at Friday Harbor Laboratories, WA, honoring the pioneering work of A.O. Dennis Willows, who initiated research on the sea slug Tritonia diomedea (now T. exsulans). A chance discovery while he was a student at a summer course there has, over the years, led to many insights into the roles of identified neurons in neural circuits and their influence on behavior. Among Dennis’s trainees was Peter Getting, whose later groundbreaking work on central pattern generators profoundly influenced the field and included one of the earliest uses of realistic modeling for understanding neural circuits. Research on Tritonia has led to key conceptual advances in polymorphic or multifunctional neural networks, intrinsic neuromodulation, and the evolution of neural circuits. It also has enhanced our understanding of geomagnetic sensing, learning and memory mechanisms, prepulse inhibition, and even drug-induced hallucinations. Although the community of researchers studying Tritonia has never been large, its contributions to neuroscience have been substantial, underscoring the importance of examining a diverse array of animal species rather than focusing on a small number of standard model organisms. 

We theoretically investigate the spin structure of weakly bound diatomic van der Waals molecules formed by two identical bosonic alkali atoms. Our studies were performed using known Born-Oppenheimer potentials while developing a reduced interaction potential model. Such reduced potential models are currently a key for solving certain classes of few-body problems of atoms as they decrease the numerical burden on the computation. Although the reduced potentials are significantly shallower than actual Born-Oppenheimer potentials, they still capture the main properties of the near-threshold bound states, including their spin structure, and the scattering states over a broad range of magnetic fields. At zero magnetic field, we find that the variation in spin structure across different alkali species originates from the interplay between electronic spin exchange and hyperfine interactions. To characterize this competition we introduce a single parameter that is a function of the singlet and triplet scattering lengths, the atomic hyperfine splitting constant, and the molecular binding energy. We show that this parameter can be used to classify the spin structure of vdW molecules for each atomic species. Published by the American Physical Society2025 

Since its original publication in 1789, Vaccinium virgatum has been treated by most authors as an accepted species in V. sect. Cyanococcus. In the latest comprehensive taxonomic treatment of the section, however, it is treated as a synonym of the broadly circumscribed species V. corymbosum. Here we use a combination of morphology, ploidy assessment with flow cytometry, and previously published phylogenomic analysis based on high-throughput DNA sequencing to support the taxonomic status of V. virgatum as a species to be recognized. As circumscribed here, V. virgatum occurs in the southeastern U.S. Coastal Plain from Arkansas, Texas, and southeastern Oklahoma to northeastern Florida and southeastern North Carolina. An updated taxonomic treatment of the species, including an expanded description, distribution map by county, and a representative list of specimens examined by county is included. We provide a means of distinguishing V. virgatum from V. ashei, a similar species recently also segregated from V. corymbosum, and from presumed rabbiteye blueberry escapes from cultivation, which can occur both within and outside the native range of V. virgatum. We designate a neotype for V. virgatum and lectotypes for V. virgatum vars. angustifolium, parvifolium, and speciosum.