Heterometallic Molecular and Ionic Isomers.

Numerous descriptions of structural isomerism in metal complexes do not list any molecular vs ionic isomers. At the same time, one of the most striking examples of structural isomerism in organic chemistry is molecular urea, which has the same atomic composition as the chemically distinct ionic ammonium cyanate. This iconic organic couple now meets its inorganic heterometallic counterpart.

Chemically Separable Co(II) Spin-State Isomers.

The phenomenon of spin crossover involves coordination complexes with switchable spin states. This spin state change is accompanied by significant geometric changes such that low and high spin forms of a complex are distinct isomers that exist in equilibrium with one another. Typically, spin-state isomers interconvert rapidly and are similar enough in polarity to prevent their independent separation and isolation.

Molecular Flexibility in Solvated Crystals of the Dimer, Au(μ-1,2-bis(diphenylphosphino)ethane)I, with Three-Coordinate Gold(I).

We report the ability to trap the dimer Au(μ-dppe)I (dppe is 1,2-bis(diphenylphosphino)ethane) with different separations between the three-coordinate gold ions in crystalline solvates. All of these solvates ((Au(μ-dppe)I·4(CHCl) (), Au(μ-dppe)I·2(CHCl) (), the polymorphs α-Au(μ-dppe)I·2(HC(O)NMe) () and β-Au(μ-dppe)I·2(HC(O)NMe) (), and Au(μ-dppe)I·4(CHCl) ()) along with polymeric {Au(μ-dppe)I}·(CHCl) ()) originated from the same reaction, only the solvent system used for crystallization differed. In the different solvates of Au(μ-dppe)I, the Au···Au separation varied from 3.

Computational Analysis of Low Overpotential Ammonia Oxidation by Metal-Metal Bonded Ruthenium Catalysts, and Predictions for Related Osmium Catalysts.

The catalyzed electrochemical oxidation of ammonia to nitrogen (AOR) is an important fuel-cell half-reaction that underpins a future nitrogen-based energy economy. Our laboratory has reported spontaneous chemical and electrochemical oxidation of ammonia to dinitrogen via reaction of ammonia with the metal-metal bonded diruthenium complex Ru(chp)OTf (chp = 2-chloro-6-hydroxypyridinate, TfO = trifluoromethanesulfonate). This complex facilitates electrocatalytic ammonia oxidation at mild applied potentials of -255 mV vs ferrocene, which is the [Ru(chp)(NH)] redox potential.

An Integrated Metabolomics-Based Model, and Identification of Potential Biomarkers, of Perfluorooctane Sulfonic Acid Toxicity in Zebrafish Embryos.

Known for their high stability and surfactant properties, per- and polyfluoroalkyl substances (PFAS) have been widely used in a range of manufactured products. Despite being largely phased out due to concerns regarding their persistence, bioaccumulation, and toxicity, legacy PFAS such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid continue to persist at high levels in the environment, posing risks to aquatic organisms. We used high-resolution magic angle spinning nuclear magnetic resonance spectroscopy in intact zebrafish (Danio rerio) embryos to investigate the metabolic pathways altered by PFOS both before and after hatching (i.

Ligand-Metal Cooperation Enables Net Ring-Opening C-C Activation / Difunctionalization of Cyclopropyl Ketones.

Reactions that cleave C-C bonds and enable functionalization at both carbon sites are powerful strategic tools in synthetic chemistry. Stereodefined cyclopropyl ketones have become readily available and would be an ideal source of 3-carbon fragments, but general approaches to net C-C activation / difunctionalization are unknown. Herein we demonstrate the cross-coupling of cyclopropyl ketones with organozinc reagents and chlorotrimethylsilane to form 1,3-difunctionalized, ring-opened products.

Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates.

A series of chiral bowl-shaped diruthenium(II,III) tetracarboxylate catalysts were prepared and evaluated in asymmetric cyclopropanations with donor/acceptor carbenes derived from aryldiazoacetates. The diruthenium catalysts self-assembled to generate -symmetric bowl-shaped structures in an analogous manner to their dirhodium counterparts. The optimum catalyst was found to be Ru(-TPPTTL)·BAr [-TPPTTL = ()-2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate, BAr = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate], which resulted in the cyclopropanation of a range of substrates in up to 94% ee.

High-Resolution Magic Angle Spinning (HRMAS) NMR Identifies Oxidative Stress and Impairment of Energy Metabolism by Zearalenone in Embryonic Stages of Zebrafish (), Olive Flounder () and Yellowtail Snapper ().

Zearalenone (ZEA) is a mycotoxin, commonly found in agricultural products, linked to adverse health impacts in humans and livestock. However, less is known regarding effects on fish as both ecological receptors and economically relevant "receptors" through contamination of aquaculture feeds. In the present study, a metabolomics approach utilizing high-resolution magic angle spinning nuclear magnetic resonance (HRMAS NMR) was applied to intact embryos of zebrafish (), and two marine fish species, olive flounder () and yellowtail snapper (), to investigate the biochemical pathways altered by ZEA exposure.

A Remarkably Unsymmetric Hexairon Core Embraced by Two High-Symmetry Tripodal Oligo-α-pyridylamido Ligands.

Oligo-α-pyridylamides offer an appealing route to polyiron complexes with short Fe-Fe separations and large room-temperature magnetic moments. A derivative of tris(2-aminoethyl)amine (Htren) containing three oligo-α-pyridylamine branches and 13 nitrogen donors (HL) reacts with [Fe(Mes)] to yield an organic nanocage built up by two tripodal ligands with interdigitated branches (HMes = mesitylene). The nanocage has crystallographic symmetry but hosts a remarkably unsymmetric hexairon-oxo core, with a central Fe(μ-O) square pyramid, two oxygen donors bridging basal sites, and an additional Fe center residing in one of the two tren-like pockets.

Basic values as a motivational framework relating individual values with acculturation strategies among Arab immigrants and refugees across different settlement contexts.

There is a lack of systematic acculturation research on the motivations underpinning the behavior of migrants, which could explain how they acculturate and adapt to their new country of residence. This paper examines the link between values, using the Schwartz Theory of Basic Human Values, and acculturation strategies among Arab immigrant and refugee groups across different settlement contexts. The results of Study 1 (Arab immigrants;  = 456) showed, as hypothesized, positive links between strategies and values: the integration strategy with conservation, social focus, self-protection, and self-transcendence values; assimilation with openness to change, personal focus, and growth values; and separation with conservation, social focus, and self-protection.

Computational analysis of metal-metal bonded dimetal tetrabenzoate redox potentials in the context of ammonia oxidation electrocatalysis.

Metal-metal bonded complexes are promising candidates for catalyzing redox transformations. Of particular interest is the oxidation of ammonia to dinitrogen, an important half reaction for the potential utilization of ammonia as a fuel or hydrogen carrier. This work computationally explores 30 different metal-metal bonded dimers (5 different metal centers and 6 different benzoate ligand derivatives) to explore the tunability of the redox potential when ammonia is bound to the complexes as an axial ligand, modeling the first step in ammonia oxidation electrocatalysis.

Spectroscopic and Magnetic Studies of Co(II) Scorpionate Complexes: Is There a Halide Effect on Magnetic Anisotropy?

The observation of single-molecule magnetism in transition-metal complexes relies on the phenomenon of zero-field splitting (ZFS), which arises from the interplay of spin-orbit coupling (SOC) with ligand-field-induced symmetry lowering. Previous studies have demonstrated that the magnitude of ZFS in complexes with 3d metal ions is sometimes enhanced through coordination with heavy halide ligands (Br and I) that possess large free-atom SOC constants. In this study, we systematically probe this "heavy-atom effect" in high-spin cobalt(II)-halide complexes supported by substituted hydrotris(pyrazol-1-yl)borate ligands (Tp and Tp).

Clarifying the structures of imidines: using crystallographic characterization to identify tautomers and localized systems of π-bonding.

Nitrogen heterocycles are a class of organic compounds with extremely versatile functionality. Imidines, HN[C(NH)R], are a rare class of heterocycles related to imides, HN[C(O)R], in which the O atoms of the carbonyl groups are replaced by N-H groups. The useful synthesis of the imidine compounds succinimidine and glutarimidine, as well as their partially hydrolyzed imino-imide congeners, was first described in the mid-1950s, though structural characterization is presented for the first time in this article.

Self-Assembled Encapsulation of CuX (X = Br, Cl) in a Gold Phosphine Box-like Cavity with Metallophilic Au-Cu Interactions.

Synthetic routes to the crystallization of two new box-like complexes, [Au(Triphos)(CuBr)](OTf)·(CHCl)·(CHOH)·(HO) () and [Au(Triphos) (CuCl)](PF)·(CHCl) () (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine), have been developed. The two centrosymmetric cationic complexes have been structurally characterized through single-crystal X-ray diffraction and shown to contain a CuX (X = Br or Cl) unit suspended between two Au(I) centers without the involvement of bridging ligands. These colorless crystals display green luminescence (λ = 527 nm) for () and teal luminescence (λ = 464 nm) for ().

An Adaptationist Framework to Examine Intergroup Contact.

Background: Many culturally-plural societies like Canada or Russia seek ways to manage their cultural diversity in order to promote harmony among coexisting groups. The social sciences have long viewed intergroup contact as a beneficial intervention to achieve such harmony.

Objective: This paper proposes an adaptationist framework within which to explain how and why intergroup contact contributes to the positive and negative outcomes for individuals who live together in a plural society.

More Similarity if Different, More Difference if Similar: Assimilation, Colorblindness, Multiculturalism, Polyculturalism, and Generalized and Specific Negative Intergroup Bias.

The creation of a social climate where all ethnic groups can harmoniously coexist is a central challenge for many countries today. Should we emphasize similarities and common ground or, conversely, recognize that there are important differences between groups? The current study examined relations between diversity ideologies (assimilation, colorblindness, multiculturalism, polyculturalism) and generalized and specific intergroup bias (against Chechens, Belarusians, Uzbeks, Chinese, and Jews and Muslims) among ethnic Russians (N = 701). In Study 1, colorblindness (ignoring differences) and polyculturalism (emphasizing interconnectivity) were associated with lower generalized intergroup bias and lower bias against Chechens, Uzbeks, and Chinese, but not Belarusians.

Validation of the Revised Multicultural Ideology Scale (MCI-r) in the UK.

As worldwide migration continues to grow, valid and reliable instruments are needed to assess the psychological processes that influence the successful management of intercultural relations in different sociopolitical contexts. In this study, we test whether the original Multicultural Ideology Scale (MCI) required a revision to remain 'fit for purpose' in the current culturally plural context of the UK (MCI-r). Specifically, six subscales are proposed to underlie the construct of a multicultural ideology: Cultural Maintenance, Equity/Inclusion, Social interaction, Essentialistic Boundaries, Extent of Differences, and Consequences of Diversity.

Divergent C-H Amidations and Imidations by Tuning Electrochemical Reaction Potentials.

Electrochemical C-H functionalizations are attractive transformations, as they are capable of avoiding the use of transition metals, pre-oxidized precursors, or suprastoichiometric amounts of terminal oxidants. Herein an electrochemically tunable method was developed that enabled the divergent formation of cyclic amines or imines by applying different reaction potentials. Detailed cyclic voltammetry analyses, coupled with chronopotentiometry experiments, were carried out to provide insight into the mechanism, while atom economy was assessed through a paired electrolysis.

Metal-Metal Bond in Heterometallic Extended Metal Atom Chains.

Understanding the fundamental properties governing metal-metal interactions is crucial to understanding the electronic structure and thereby applications of multimetallic systems in catalysis, material science, and magnetism. One such property that is relatively underexplored within multimetallic systems is metal-metal bond polarity, parameterized by the electronegativities (χ) of the metal atoms involved in the bond. In heterobimetallic systems, metal-metal bond polarity is a function of the donor-acceptor (Δχ) interactions of the two bonded metal atoms, with electropositive early transition metals acting as electron acceptors and electronegative late transition metals acting as electron donors.

An integrated systems-level model of ochratoxin A toxicity in the zebrafish (Danio rerio) embryo based on NMR metabolic profiling.

Ochratoxin A (OTA) is one of the most widespread mycotoxin contaminants of agricultural crops. Despite being associated with a range of adverse health effects, a comprehensive systems-level mechanistic understanding of the toxicity of OTA remains elusive. In the present study, metabolic profiling by high-resolution magic angle spinning (HRMAS) NMR, coupled to intact zebrafish embryos, was employed to identify metabolic pathways in relation to a systems-level model of OTA toxicity.

Postsynthetic Treatment of ZIF-67 with 5-Methyltetrazole: Evolution from Pseudo-T to Pseudo-O Symmetry and Collapse of Magnetic Ordering.

Reaction of Co(II) nitrate with 2-methylimidazole (2mIm) yields ZIF-67, the structure of which features Co(II) ions in pseudo-tetrahedral coordination geometry. Strong antiferromagnetic interactions between Co(II) ions mediated by the 2mIm ligands lead to antiferromagnetic ordering at 22 K. Postsynthetic treatment of Co(II) ZIF-67 with 5-methyltetrazole (5mT) results in the loss of crystallinity and magnetic order.

Electronic Structure of Ru Complexes with Electron-Rich Anilinopyridinate Ligands.

Diruthenium paddlewheel complexes supported by electron-rich anilinopyridinate (Xap) ligands were synthesized in the course of the first in-depth structural and spectroscopic interrogation of monocationic [Ru(Xap)Cl] species in the Ru oxidation state. Despite paramagnetism of the compounds, H NMR spectroscopy proved highly informative for determining the isomerism of the Ru and Ru compounds. While most compounds are found to have the polar (4,0) geometry, with all four Xap ligands in the same orientation, some synthetic procedures resulted in a mixture of (4,0) and (3,1) isomers, most notably in the case of the parent compound Ru(ap)Cl.