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The first gold dipyrrin-bisphenolates have been synthesized. Like their corrole analogues, they exhibit Au III –L 3− ground states, providing rare innocent paradigms for a class of complexes that commonly occur as metalloradicals.
Intermolecular interactions between radicals and closed-shell molecules are ubiquitous in chemical processes, ranging from the benchtop to the atmosphere and extraterrestrial space. While energy decomposition analysis (EDA) schemes for closed-shell molecules can be generalized for studying radical–molecule interactions, they face challenges arising from the unique characteristics of the electronic structure of open-shell species. In this work, we introduce additional steps that are necessary for the proper treatment of radical–molecule interactions to our previously developed unrestricted Absolutely Localized Molecular Orbital (uALMO)-EDA based on density functional theory calculations. A “polarize-then-depolarize” (PtD) scheme is used to remove arbitrariness in the definition of the frozen wavefunction, rendering the ALMO-EDA results independent of the orientation of the unpaired electron obtained from isolated fragment calculations. The contribution of radical rehybridization to polarization energies is evaluated. It is also valuable to monitor the wavefunction stability of each intermediate state, as well as their associated spin density profiles, to ensure the EDA results correspond to a desired electronic state. The examples suggest that this second generation uALMO-EDA is a useful tool for furthering one's understanding of both energetic and property changes associated with radical–molecule interactions.
Fe( ii )-porphyrins play an important role in many reactions, due to their closely lying spin states. We present a thorough study of a Fe( ii )-porphyrin model system, in which we examine how the geometrical parameters influence its spin state ordering.
Splitting of molecular hydrogen (H 2 ) into bridging and terminal hydrides is a common step in transition metal chemistry. In this paper, we propose a novel organometallic platform for cleavage of multiple H 2 molecules, which combines metal centers capable of stabilizing multiple oxidation states, and ligands bearing positioned pendant basic groups. Using quantum chemical modeling, we show that low-valent, early transition metal diniobium(II) complexes with diphosphine ligands featuring pendant amines can favorably uptake up to 8 hydrogen atoms, and that the energetics are favored by the formation of intramolecular dihydrogen bonds. This result suggests new possible strategies for the development of hydrogen scavenger molecules that are able to perform reversible splitting of multiple H 2 molecules.
Predictions of high thermoelectric performance in RECuZnP 2 were verified by elastic, electrical, and thermal measurements. Low thermal conductivities result from strong anharmonicity, with electron transport limited by polar optical phonons.
The next-generation indium-based lead-free halide material Cs 2 InAgCl 6 is promising for photovoltaic applications due to its good air stability and non-toxic behavior while it shows good thermoelectric properties when doped with Pb.
The solvation shell structures of Ca 2+ in solutions are probed by calcium L-edge soft X-ray XAS and DFT/MD simulations.
From quantum chemical and experimental NMR data, a 3D graph neural network, CASCADE, has been developed to predict carbon and proton chemical shifts. Stereoisomers and conformers of organic molecules can be correctly distinguished.
Structure-driven evolution of magnetic behaviour of AuCo nanoparticles showcases efficacy of the elementary intermixing in enhancing magnetisation and magnetic anisotropy.
We report the synthesis and structure of the most highly distorted four-coordinate d 3 ion known to date that also serves as the second known example of a bis(biphenolato) transition metal complex. We demonstrate the application of density functional theory to calculate the magnetic parameters derived from the experimental and simulated EPR spectra.
High reducible distorted bimetallic sites with medium size in Ni 5 Co 5 -AC promoted the production of cyclohexanol by hydrogenation of anisole and subsequent cleavage of C 6 H 11 O–CH 3 bond.
Appropriately identifying and treating molecules and materials with significant multi-reference (MR) character is crucial for achieving high data fidelity in virtual high-throughput screening (VHTS). Despite development of numerous MR diagnostics, the extent to which a single value of such a diagnostic indicates the MR effect on a chemical property prediction is not well established. We evaluate MR diagnostics for over 10 000 transition-metal complexes (TMCs) and compare to those for organic molecules. We observe that only some MR diagnostics are transferable from one chemical space to another. By studying the influence of MR character on chemical properties (i.e., MR effect) that involve multiple potential energy surfaces (i.e., adiabatic spin splitting, ΔE H–L , and ionization potential, IP), we show that differences in MR character are more important than the cumulative degree of MR character in predicting the magnitude of an MR effect. Motivated by this observation, we build transfer learning models to predict CCSD(T)-level adiabatic ΔE H–L and IP from lower levels of theory. By combining these models with uncertainty quantification and multi-level modeling, we introduce a multi-pronged strategy that accelerates data acquisition by at least a factor of three while achieving coupled cluster accuracy (i.e., to within 1 kcal mol –1 MAE) for robust VHTS.
In addition to the semiconducting phase in AgNi 0.66 Co 0.33 O 2 , it is found that the coexistence of metallic phase when more than x = 0.33 of Co dopant is substituted in the single layer of NiO 2 in AgNi 0.66 Co 0.33 O 2 .
The interactions between Hf and CO are studied using multi-reference, couple cluster, and density functional theory. Calculations suggest that B3LYP is suitable for representing both molecular and solid-state models of Hf-CO interactions.
Non-equilibrium plasma has been found to have a synergistic effect on catalytic synthesis of NH 3 .
The impact of explicit water molecules on the binding of two rare earth nitrate aqua complexes, [X(NO 3 ) 3 (H 2 O) n ] (X = Nd, Yb), has been explored on both the internal pores and external surfaces of MCM-22.
The optical properties of the tetragonal phase of BaTiO 3 have been studied using density functional methods, applying the generalized gradient approximation at room temperature and a hybrid functional for static lattice analysis.
A schematic for the preparation of a g-C 3 N 4 -CNT/S composite cathode for lithium–sulfur batteries.