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The accuracy and the usefulness of density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations for the theoretical study of Ln (La, Eu, Lu) complexes are investigated. The geometries calculated at the DFT level for [Ln(H2O)(sub n)L](super 3 +) complexes are successfully compared with crystallographic data.

The search for new ligands capable of modifying the metal nanoparticle (MNP) catalytic behavior is of increasing interest. Herein we present the first example of RuNPs stabilized with non-planar heptagon-containing saddle-shaped nanographenes (Ru@1 and Ru@2). The resemblance to graphene-supported MNPs makes these non-planar nanographene-stabilized RuNPs very attractive systems to further investigate graphene-metal interactions. A combined theoretical/experimental study allowed us to explore the coordination modes and dynamics of these nanographenes at the Ru surface. The curvature of these saddle-shaped nanographenes makes them efficient MNP stabilizers. The resulting RuNPs were found to be highly active catalysts for the hydrogenation of aromatics, including platform molecules derived from biomass ( i.e. HMF) or liquid organic hydrogen carriers ( i.e. N -indole). A significant ligand effect was observed since a minor modification on the hept-HBC structure (C[double bond, length as m-dash]CH 2 instead of C[double bond, length as m-dash]O) was reflected in a substantial increase in the MNP activity. Finally, the stability of these canopied RuNPs was investigated by multiple addition experiments, proving to be stable catalysts for at least 96 h., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

To shed light on the factors governing the stability and surface properties of iron nanoparticles, a series of iron nanoparticles has been produced by hydrogenation of two different iron amido complexes: the bis[bis(trimethylsilyl)amido] Fe(ii), [Fe(N(SiMe 3 ) 2 ) 2 ] 2 , and the bis(diphenylamido) Fe(ii), [Fe(NPh 2 ) 2 ]. Nanostructured materials of bcc structure, or nanoparticles displaying average sizes below 3 nm and a polytetrahedral structure, have been obtained. Depending on the synthesis conditions, the magnetization of the nanoparticles was either significantly lower than that of bulk iron, or much higher as for clusters elaborated under high vacuum conditions. Unexpectedly, hydrogenation of aromatic groups of the ligands of the [Fe(NPh 2 ) 2 ] precursor has been observed in some cases. Confrontation of the experimental results with DFT calculations made on polytetrahedral Fe 91 model clusters bearing hydrides, amido and/or amine ligands at their surface, has shown that amido ligands can play a key role in the stabilisation of the nanoparticles in solution while the hydride surface coverage governs their surface magnetic properties. This study indicates that magnetic measurements give valuable indicators of the surface properties of iron nanoparticles in this size range, and beyond, of their potential reactivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Ultrasmall gold nanoparticles (NPs) stabilized in networks by polymantane ligands (diamondoids) were successfully used as precatalysts for highly selective heterogeneous gold-catalyzed dimethyl allyl(propargyl)malonate cyclization to 5-membered conjugated diene. Such reaction usually suffers from selectivity issues with homogeneous catalysts. This control over selectivity further opened the way to one-pot cascade reaction, as illustrated by the 1,6-enyne cycloisomerization-Diels-Alder reaction of dimethyl allyl propargyl malonate with maleic anhydride. The ability to assemble nanoparticles with controllable sizes and shapes within networks concerns research in sensors, medical diagnostics, information storage, and catalysis applications. Herein, the control of the synthesis of sub-2-nm gold NPs is achieved by the formation of dense networks, which are assembled in a single step reaction by employing ditopic polymantanethiols. By using 1,1'-bisadamantane-3,3'-dithiol (BAd-SH) and diamantane-4,9-dithiol (DAd-SH), serving both as bulky surface stabilizers and short-sized linkers, we provide a simple method to form uniformly small gold NPs (1.3 ± 0.2 nm to 1.6 ± 0.3 nm) embedded in rigid frameworks. These NP arrays are organized alongside short interparticular distances ranging from 1.9 to 2.7 nm. The analysis of gold NP surfaces and their modification were achieved in joint experimental and theoretical studies, using notably XPS, NMR, and DFT modeling. Our experimental studies and DFT analyses highlighted the necessary oxidative surface reorganization of individual nanoparticles for an effective enyne cycloisomerization. The modifications at bulky stabilizing ligands allow surface steric decongestion for the alkyne moiety activation but also result in network alteration by overoxidation of sulfurs. Thus, sub-2-nm nanoparticles originating from networks building create convenient conditions for generating reactive Au(I) surface single-sites-in the absence of silver additives-useful for heterogeneous gold-catalyzed enyne cyclization. These nanocatalysts, which as such ease organic products separation, also provide a convenient access for building further polycyclic complexity, owing to their high reactivity and selectivity., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

We apply a pattern-based classification method to identify clinical and genomic features associated with the progression of Chronic Kidney disease (CKD). We analyze the African-American Study of Chronic Kidney disease with Hypertension dataset and construct a decision-tree classification model, consisting 15 combinatorial patterns of clinical features and single nucleotide polymorphisms (SNPs), seven of which are associated with slow progression and eight with rapid progression of renal disease among African-American Study of Chronic Kidney patients. We identify four clinical features and two SNPs that can accurately predict CKD progression. Clinical and genomic features identified in our experiments may be used in a future study to develop new therapeutic interventions for CKD patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Moreno, Bain, Moreno, Carroll, Cunningham, Ashton, Poteau, Subasi, Lipkowitz and Subasi.)

Grafting catalysts on a surface leads to heterogeneous catalysts with well-defined active sites. However, the grafting mode of a lanthanum complex onto silica remains unknown. To shed light on this grafting reaction, different studies have been achieved in the framework of density functional theory. The silica substrate hydroxylated at 700 degrees C has been simulated both by molecular and periodic models. The created molecular models are in agreement with the rigidity of the ligand, the surface density of silanol groups, and the different spectroscopic data of a silica surface partially dehydroxylated at 700 degrees C. Two possible models of surface have henceforth been considered: the first one with one isolated silanol and the second one with two vicinal silanols linked by a siloxane bridge. The thermodynamics of a grafting reaction of lanthanum catalysts on these models has also been investigated. This reaction leads to thermodynamically stable structures that reveal different types of grafting: monografted, bigrafted, or bigrafted after breaking of a Si-O-Si bridge. Similarly to experimental approaches, coordination of triphenylphosphine oxide (O=PPh(3)) has also been considered as a probe of the grafting mode. A good agreement between the theoretical and the experimental spectroscopic values has systematically been found, but none of the grafting modes seem to be more relevant. Accordingly, it is necessary to consider in subsequent studies that all grafting modes coexist, increasing the difficulty to theoretically investigate multistep reactions.

To account for the scarcity of cis peptide bonds in proteins, especially in nonproline (or secondary amide) cases, a steric-clash argument is often put forward, in a scheme where the R lateral chains are facing parallel one another, and the backbone is kept in an "all- trans"-like arrangement. Although such a steric conflict can be partly relieved through proper adjustment of the backbone dihedral angles, one can try to estimate its associated energy cost. To this end, quantum-chemistry approaches using a differential-torsion protocol and bond-separation-energy analyses are applied to N-ethyl propionamide CH3-CH2-CO-NH-CH2-CH3, regarded as a model capable of exhibiting C beta...C beta interaction as in alanine succession. The calculations provide an increment of 9 kcal/mol, quite close to that obtained in the nearly isostere (gsg) rotamer of n-hexane (10 kcal/mol), suggesting the local effects induced by methyl-methyl contact are similar in both cases. Analogous treatments on larger radicals as encountered in leucine or phenylalanine dimers do not change this increment much, which therefore defines the basic reference per-plaque quota to be overcome along all- cis chains. Explicit modeling indicated it can be reduced by up to a factor of 4.

The possibility of all-cis open-chain polypeptides is rarely addressed, owing to three main reasons, namely, (i) the extreme scarcity of cis peptide bonds in naturally occurring proteins and peptides, (ii) the lesser thermodynamic stability (by about 2.5 kcal/mol) of cis amide bonds with respect to their trans counterparts, and (iii) widely held preconceptions about the so-called "steric clash" between lateral chains borne by two successive alpha carbons. Quantum-chemistry calculations performed on alanine tridecamers show how the latter constraints can be efficiently relieved through proper phi/psi adjustments along the backbone, leading to several helical arrangements--presumably the only permitted regular structures. Four more-or-less regular helices were thus characterized, one of them, a superhelix, exhibiting intramolecular hydrogen bonds. Understanding and anticipating all-cis open-chain structures not only make use of the classical Ramachandran maps at each C alpha i, relating to E = f(phi i,psi i), but also require the profile of a new kind of conformational dependence, the plaque maps, relating to E = f(phi i,psi i-1). The obvious coupling between two such maps enforces conformational dependence between two consecutive C alpha's, somewhat questioning in this context the customary "local effects", and presumably reducing the whole chain plasticity. Whereas cis thermodynamic penalty cannot be abolished locally, energy clues indicate that assembling cis-prepared building units is an exothermic process. Besides, once built up, the all-cis backbone should be difficult to unlock, thus affording reasonable kinetic stability.