Fast and Robust Modeling of Lanthanide and Actinide Complexes, Biomolecules, and Molecular Crystals with the Extended GFN-FF Model.

Lanthanides (Ln) and actinides (An) have recently become important tools in biomedical and materials science. However, the development of computational methods able to describe such elements in various environments has not kept up with the pace of the field. Addressing this challenge, this work introduces and showcases an extension of the GFN-FF to An alongside a reparameterization for Ln.

The p-block challenge: assessing quantum chemistry methods for inorganic heterocycle dimerizations.

The elements of the p-block of the periodic table are of high interest in various chemical and technical applications like frustrated Lewis-pairs (FLP) or opto-electronics. However, high-quality benchmark data to assess approximate density functional theory (DFT) for their theoretical description are sparse. In this work, we present a benchmark set of 604 dimerization energies of 302 "inorganic benzenes" composed of all non-carbon p-block elements of main groups III to VI up to polonium.

Benchmark Study on the Calculation of Pb NMR Chemical Shifts.

A benchmark set for the computation of Pb nuclear magnetic resonance (NMR) chemical shifts is presented. The set includes conformer ensembles of 50 lead-containing molecular compounds and their experimentally measured Pb NMR chemical shifts. Various bonding motifs at the Pb center with up to seven bonding partners are included.

Improving Quantum Chemical Solvation Models by Dynamic Radii Adjustment for Continuum Solvation (DRACO).

We present the Dynamic Radii Adjustment for COntinuum solvation (DRACO) approach, which employs precomputed atomic partial charges and coordination numbers of the solute atoms to improve the solute cavity. As such, DRACO is compatible with major solvation models, improving their performance significantly and robustly at virtually no extra cost, especially for charged solutes. Combined with the purely electrostatic CPCM and COSMO models, DRACO reduces the mean absolute deviation (MAD) of the solvation free energy by up to 4.

Hybrid DFT Geometries and Properties for 17k Lanthanoid Complexes─The LnQM Data Set.

The unique properties of lanthanoids and their diverse applications make them an indispensable part of modern research and industry. While the field has garnered attention, there remains a gap in available molecule data sets that facilitate both classical quantum chemistry calculations and the burgeoning field of machine learning in data science applications. This research addresses the need for a comprehensive data set that allows for a comparative analysis of various lanthanoids.

Machine learning-based correction for spin-orbit coupling effects in NMR chemical shift calculations.

As one of the most powerful analytical methods for molecular and solid-state structure elucidation, NMR spectroscopy is an integral part of chemical laboratories associated with a great research interest in its computational simulation. Particularly when heavy atoms are present, a relativistic treatment is essential in the calculations as these influence also the nearby light atoms. In this work, we present a Δ-machine learning method that approximates the contribution to C and H NMR chemical shifts that stems from spin-orbit (SO) coupling effects.

Influence of Steric and Dispersion Interactions on the Thermochemistry of Crowded (Fluoro)alkyl Compounds.

ConspectusAlkanes play a pivotal role in industrial, environmental, and biological processes. They are characterized by their carbon-carbon single-bond structure, remarkable stability, and conformational diversity. Fluorination of such compounds imparts unique physicochemical properties that often enhance pharmacokinetic profiles, metabolic stability, and receptor interactions while keeping beneficial properties.

Dispersion-corrected r2SCAN based double-hybrid functionals.

The regularized and restored semi-local meta-generalized gradient approximation (meta-GGA) exchange-correlation functional r2SCAN [Furness et al., J. Phys.

Confined Lewis Pairs: Investigation of the X →Si Interaction in Halogen-Encapsulating Silafulleranes.

A joint theoretical and experimental study on 32 endohedral silafullerane derivatives [X@Si Y ] (X=F-I; Y=F-I, H, Me, Et) and -[Cl@Si H Y ] (Y=F-I) is presented. First, we evaluated the structure-determining template effect of Cl in a systematic series of concave silapolyquinane model systems. Second, we investigated the X →Si interaction energy ( ) as a function of X and Y and found the largest values for electron-withdrawing exohedral substituents Y.

Assessment of DLPNO-MP2 Approximations in Double-Hybrid DFT.

The unfavorable scaling () of the conventional second-order Møller-Plesset theory (MP2) typically prevents the application of double-hybrid (DH) density functionals to large systems with more than 100 atoms. A prominent approach to reduce the computational demand of electron correlation methods is the domain-based local pair natural orbital (DLPNO) approximation that is successfully used in the framework of DLPNO-CCSD(T). Its extension to MP2 [Pinski P.

Modular Bicyclophane-Based Molecular Platforms.

The modular synthesis of a series of nanoscale phenylene bicyclophanes with an intraannular orthogonal pillar is described. The compounds are obtained by a Suzuki cross-coupling condensation and are characterized by mass spectrometry and NMR spectroscopy as well as in situ scanning tunneling microscopy at the solid/liquid interface of highly ordered pyrolytic graphite. In addition, their structures and conformations are supported by quantum chemical calculations, also after adsorption to the substrate.

ONIOM meets : efficient, accurate, and robust multi-layer simulations across the periodic table.

The computational treatment of large molecular structures is of increasing interest in fields of modern chemistry. Accordingly, efficient quantum chemical approaches are needed to perform sophisticated investigations on such systems. This engaged the development of the well-established "Our own N-layered integrated molecular orbital and molecular mechanics" (ONIOM) multi-layer scheme [L.

Brominated [20]silafulleranes: pushing the limits of steric loading.

Starting from the perhydrogenated silafullerane [BuN][Cl@Si(SiH)H], treatment with BBr leads to partially and exhaustively brominated clusters, [BuN][Cl@Si(SiBrH)Br] (120 eq. BBr, room temperature, 30 min) and [BuN][Cl@Si(SiBr)Br] (300 eq. BBr, 130 °C, 3 d).

Regioselective Derivatization of Silylated [20]Silafulleranes.

Silafulleranes with endohedral Cl ions are a unique, scarcely explored class of structurally well-defined silicon clusters and host-guest complexes. Herein, we report regioselective derivatization reactions on the siladodecahedrane [BuN][Cl@Si(SiCl)Cl] ([BuN][]), which has its cluster surface decorated with 12 SiCl and 8 Cl substituents in perfect symmetry. The room-temperature reaction of [BuN][] with excess BuAlH in -difluorobenzene (DFB) furnishes perhydrogenated [BuN][Cl@Si(SiH)H] ([BuN][]) in 50% yield; the non-pyrophoric [] is the largest structurally authenticated (by X-ray diffraction) hydridosilane known to date.

London Dispersion Effects in a Distannene/Tristannane Equilibrium: Energies of their Interconversion and the Suppression of the Monomeric Stannylene Intermediate.

Reaction of {LiC H -2,4,6-Cyp ⋅Et O} (Cyp=cyclopentyl) (1) of the new dispersion energy donor (DED) ligand, 2,4,6-triscyclopentylphenyl with SnCl afforded a mixture of the distannene {Sn(C H -2,4,6-Cyp ) } (2), and the cyclotristannane {Sn(C H -2,4,6-Cyp ) } (3). 2 is favored in solution at higher temperature (345 K or above) whereas 3 is preferred near 298 K. Van't Hoff analysis revealed the 3 to 2 conversion has a ΔH=33.

Best-Practice DFT Protocols for Basic Molecular Computational Chemistry.

Nowadays, many chemical investigations are supported by routine calculations of molecular structures, reaction energies, barrier heights, and spectroscopic properties. The lion's share of these quantum-chemical calculations applies density functional theory (DFT) evaluated in atomic-orbital basis sets. This work provides best-practice guidance on the numerous methodological and technical aspects of DFT calculations in three parts: Firstly, we set the stage and introduce a step-by-step decision tree to choose a computational protocol that models the experiment as closely as possible.

Optimization of the rSCAN-3c Composite Electronic-Structure Method for Use with Slater-Type Orbital Basis Sets.

The "Swiss army knife" composite density functional electronic-structure method rSCAN-3c ( , , 064103) is extended and optimized for the use with Slater-type orbital basis sets. The meta generalized-gradient approximation (meta-GGA) functional rSCAN by Furness et al. is combined with a tailor-made polarized triple-ζ Slater-type atomic orbital (STO) basis set (mTZ2P), the semiclassical London dispersion correction (D4), and a geometrical counterpoise (gCP) correction.

Computational study of ground-state properties of μ -bridged group 14 porphyrinic sandwich complexes.

The structural properties of μ -bridged porphyrinic double-decker complexes are investigated and the influence of various ligands, metals, substituents, and bridging atoms on the dominant structural motif is elucidated. A variety of quantum chemical methods including semiempirical (SQM) methods and density functional theory (DFT) is assessed for the calculation of ecliptic and staggered conformational energies. Local coupled cluster (DLPNO-CCSD(T1)) data are generated for reference.

Dispersion corrected rSCAN based global hybrid functionals: rSCANh, rSCAN0, and rSCAN50.

The regularized and restored semilocal meta-generalized gradient approximation (meta-GGA) exchange-correlation functional rSCAN [Furness et al., J. Phys.

Benchmark Study on the Calculation of Sn NMR Chemical Shifts.

A new benchmark set termed for assessing quantum chemical methods for the computation of Sn NMR chemical shifts is presented. It covers 51 unique Sn NMR chemical shifts for a selection of 50 tin compounds with diverse bonding motifs and ligands. The experimental reference data are in the spectral range of ±2500 ppm measured in seven different solvents.

Designing a Solution-Stable Distannene: The Decisive Role of London Dispersion Effects in the Structure and Properties of {Sn(CH-2,4,6-Cy)} (Cy = Cyclohexyl).

The reaction of 1 equiv of the dimeric lithium salt of a new London dispersion effect donor ligand {Li(CH-2,4,6-Cy)·OEt} (Cy = cyclohexyl) with SnCl afforded the distannene {Sn(CH-2,4,6-Cy)} (). The distannene remains dimeric in solution, as indicated by its room-temperature Sn NMR signal (δ = 361.3 ppm) and its electronic spectrum, which is invariant over the temperature range of -10 to 100 °C.

Quickstart guide to model structures and interactions of artificial molecular muscles with efficient computational methods.

Artificial molecular muscles (AMMs) represent an important group of molecular machines. Their theoretical treatment is challenging due to size, element composition, and complex interaction motifs. Moreover, experimentally determined structures often only yield insights into the covalent connectivity of atoms rather than their 3D structure.

The power of trichlorosilylation: isolable trisilylated allyl anions, allyl radicals, and allenyl anions.

Treatment of hexachloropropene (ClC[double bond, length as m-dash]C(Cl)-CCl) with SiCl and [BuN]Cl (1 : 4 : 1) in CHCl results in a quantitative conversion to the trisilylated, dichlorinated allyl anion salt [BuN][ClC[double bond, length as m-dash]C(SiCl)-C(SiCl)] ([BuN][]). Tetrachloroallene ClC[double bond, length as m-dash]C[double bond, length as m-dash]CCl was identified as the first intermediate of the reaction cascade. In the solid state, [] adopts approximate symmetry with a dihedral angle between the planes running through the olefinic and carbanionic fragments of [] of C[double bond, length as m-dash]C-Si//Si-C-Si = 78.

Assessing Density Functional Theory for Chemically Relevant Open-Shell Transition Metal Reactions.

Due to the principle lack of systematic improvement possibilities of density functional theory, careful assessment of the performance of density functional approximations (DFAs) on well-designed benchmark sets, for example, for reaction energies and barrier heights, is crucial. While main-group chemistry is well covered by several available sets, benchmark data for transition metal chemistry is sparse. This is especially the case for larger, chemically relevant molecules.