Exploring the Use of "Honorary Transition Metals" To Push the Boundaries of Planar Hypercoordinate Alkaline-Earth Metals.

The quest for planar hypercoordinate atoms (phA) beyond six has predominantly focused on transition metals, with dodecacoordination being the highest reported thus far. Extending this bonding scenario to main-group elements, which typically lack d orbitals despite their larger atomic radius, has posed significant challenges. Intrigued by the potentiality of covalent bonding formation using the d orbitals of the heavier alkaline-earth metals (Ae = Ca, Sr, Ba), the so-called "honorary transition metals", we aim to push the boundaries of planar hypercoordination. By including rings formed by 12-15 atoms of boron-carbon and Ae centers, we propose a design scheme of 180 candidates with a phA. Further systematic screening, structural examination, and stability assessments identified 10 potential clusters with a planar hypercoordinate alkaline-earth metal (phAe) as the lowest-energy form. These unconventional structures embody planar dodeca-, trideca-, tetradeca-, and pentadecacoordinate atoms. Chemical bonding analyses reveal the important role of Ae d orbitals in facilitating covalent interactions between the central Ae atom and the surrounding boron-carbon rings, thereby establishing a new record for coordination numbers in the two-dimensional realm.

Medical supervised duodenal-enteral feeding for the treatment of overweight and obesity: MESUDEFT / Nutrición duodenoenteral médicamente supervisada para el tratamiento del sobrepeso y la obesidad: MESUDEFT

Background: the development of specialised nutritional support techniques allows the maintenance of an adequate supply of nutrients in those patients in whom oral feeding is not possible or is insufficient in relation to their requirements, trying to improve the quality of life, especially in those with chronic diseases. Methods: single-center clinical study carried out in a clinical-nutritional center consisting of a medically supervised nasogastric-duodenal tube feeding treatment for overweight, obesity and increased body fat percentage in patients requiring it by means of duodeno-enteral feeding, expecting losses of more than 10 %. Results: twenty-nine patients completed the protocol (20.4 % male and 79.6 % female) with a mean age of 38 years (SD: 12.4); 87.2 kg (SD: 18.5) mean weight; 37.9 kg (SD: 4.8) mean iFat%; 32.4 (SD: 5.4) iMean body mass index (BMI); 100 cm (SD: 16.0) iMean waist; 113.6 cm (SD: 10.4) iMean hip; 33.8 cm (SD: 3.9) iMean upper arm circumference; 65.5 cm (SD: 7.5) iMean thigh circumference; 9.7 (SD: 4.8) iVisceral fat index; and 22.9 days (SD: 13.9) mean treatment. A mean of 22.9 (SD: 13.9) days of MESUDEFT influences weight loss, fat loss, visceral fat loss and decreased arm, hip and thigh circumferences (p < 0.05) (i: initial). Conclusions: MESUDEFT is shown to be an effective alternative as a sole treatment or as an adjunct prior to bariatric surgery for obesity or overweight treatment with a minimum of 10 % loss of BMI and fat mass at completion and 3-6 months follow-up.(AU)

Antecedentes: el desarrollo de técnicas especializadas de soporte nutricional permite mantener un aporte adecuado de nutrientes en aquellos pacientes en los que la alimentación oral no es posible o es insuficiente en relación a sus requerimientos, intentando mejorar la calidad de vida, especialmente de aquellos con enfermedades crónicas. Métodos: estudio clínico unicéntrico prospectivo realizado en un centro clínico-nutricional consistente en un tratamiento con alimentación por sonda nasogástrica-duodenal médicamente supervisado para el sobrepeso, la obesidad y el aumento del porcentaje de grasa corporal en pacientes que lo requieran mediante alimentación duodenoenteral, durante un mes aproximado, con previsión de pérdidas superiores al 10 % y con control posterior entre los tres y los seis meses siguientes. Resultados: veintinueve pacientes completaron el protocolo (20,4 % varones y 79,6 % mujeres) con una edad media de 38 años (DE: 12,4); 87,2 kg (DE: 18,5) iPeso medio; 37,9 kg (DE: 4,8) iGrasa% media; 32,4 (DE: 5,4) iIMC medio; 100 cm (DE: 16,0) iCintura media; 113,6 cm (DE: 10,4) iCadera media; 33,8 cm (DE: 3,9) iCircunferencia braquial media; 65,5 cm (DE: 7,5) circunferencia muslo media; 9,7 (DE: 4,8) iíndice de grasa visceral; y 22,9 días (DE: 13,9) de tratamiento medio. Una media de 22,9 (DE: 13,9) días de MESUDEFT influye en la pérdida de peso, la pérdida de grasa, la pérdida de grasa visceral y la disminución de las circunferencias del brazo, la cadera y el muslo (p < 0,05) (i: inicial). Conclusiones: MESUDEFT se muestra como una alternativa eficaz como tratamiento único o como coadyuvante previo a la cirugía bariátrica de la obesidad o tratamiento del sobrepeso con una pérdida mínima del 10 % del índice de masa corporal (IMC) y de la masa grasa al finalizar y con control durante los siguientes 3-6 meses.(AU)

Breaking the plane: B5H5 is a three-dimensional structure.

In this study, we delved into the structure of B5H5 and questioned some of its accepted assumptions. By exploring the potential energy surface, we found a new three-dimensional structure as the global minimum. This finding is in contrast with the previously hypothesized planar and cage-like models. Our exploration extends to the kinetic stability of various B5H5 isomers, offering insights into the dynamic behavior of these molecules.

Volatile lanthanide complexes with fluorinated heptadentate ligands.

Understanding factors that influence the volatility of lanthanide complexes remains an important goal for applications such as gas-phase f-metal separations and the synthesis of lanthanide-containing thin films. Lanthanide complexes often exhibit volatility differences that depend on the ability of ligands to saturate the lanthanide coordination sphere and attenuate intermolecular bonding in the solid state. This can make it difficult to assess how electronic factors associated with differing ligand substituents influence volatility. Here we describe the synthesis, structures, and thermal properties of a series of volatile lanthanide complexes (Ln = Nd, Er, and Yb) containing N4O3 ligands decorated with different alkyl and fluoroalkyl substituents (CF3, CF2CF2CF3, Me, and tBu). These ligands completely enveloped the tested lanthanides to form monomeric complexes with 7-coordinate distorted capped octahedral coordination geometries, as determined using single-crystal X-ray diffraction. Thermogravimetric analysis and bulk sublimation studies show how metal encapsulation affords complexes with the same volatility regardless of metal size, even with lanthanide ions with significantly different radii such as Nd3+ and Yb3+. Most notably, the results show that increasing ligand fluorination, a strategy often used to increase the volatility of metal complexes, is not always beneficial and can significantly attenuate the volatility of lanthanide complexes depending on location with respect to other substituents in the ligand framework. A pair-wise model based on density functional theory shows that the net intermolecular interactions in the unit cell can still be stronger when fluorination is present. In other words, even if individual interactions between neighboring molecules are weaker, the total number of interactions in the solid arising from the nature of crystal packing is equally important to consider.

Medical supervised duodenal-enteral feeding for the treatment of overweight and obesity: MESUDEFT.

BACKGROUND: the development of specialised nutritional support techniques allows the maintenance of an adequate supply of nutrients in those patients in whom oral feeding is not possible or is insufficient in relation to their requirements, trying to improve the quality of life, especially in those with chronic diseases. METHODS: single-center clinical study carried out in a clinical-nutritional center consisting of a medically supervised nasogastric-duodenal tube feeding treatment for overweight, obesity and increased body fat percentage in patients requiring it by means of duodeno-enteral feeding, expecting losses of more than 10 %. RESULTS: twenty-nine patients completed the protocol (20.4 % male and 79.6 % female) with a mean age of 38 years (SD: 12.4); 87.2 kg (SD: 18.5) mean weight; 37.9 kg (SD: 4.8) mean iFat%; 32.4 (SD: 5.4) iMean body mass index (BMI); 100 cm (SD: 16.0) iMean waist; 113.6 cm (SD: 10.4) iMean hip; 33.8 cm (SD: 3.9) iMean upper arm circumference; 65.5 cm (SD: 7.5) iMean thigh circumference; 9.7 (SD: 4.8) iVisceral fat index; and 22.9 days (SD: 13.9) mean treatment. A mean of 22.9 (SD: 13.9) days of MESUDEFT influences weight loss, fat loss, visceral fat loss and decreased arm, hip and thigh circumferences (p < 0.05) (i: initial). CONCLUSIONS: MESUDEFT is shown to be an effective alternative as a sole treatment or as an adjunct prior to bariatric surgery for obesity or overweight treatment with a minimum of 10 % loss of BMI and fat mass at completion and 3-6 months follow-up.

Unveiling the electronic and structural consequences of removing two electrons from B12H122.

The notion that a regular icosahedron is unattainable in neutral B12H12 has persisted for nearly 70 years. This is because 24 valence electrons are used for B-H bonds, while another 24 electrons are necessary to maintain the deltahedron, unlike the 26 used in the dianion. According to Wade-Mingos rules, the neutral system should be a deltahedron with a capped face. Nevertheless, our exploration of the potential energy surface of B12H12 reveals that the global minimum is a closed-shell form with an H2 unit attached to a boron vertex of B12H10, preserving the deltahedral boron skeleton.

Correction: Structure and bonding of molecular stirrers with formula B7M2- and B8M2 (M = Zn, Cd, Hg).

Correction for 'Structure and bonding of molecular stirrers with formula B7M2- and B8M2 (M = Zn, Cd, Hg)' by Rui Yu et al., Phys. Chem. Chem. Phys., 2020, 22, 12312-12320, https://doi.org/10.1039/D0CP01603A.

CAl11-: a molecular rotor with a quasi-planar tetracoordinate carbon.

In this work, we analyzed the bonding and fluxional character of the global minimum of CAl11-. Its structure is formed by two stacked layers, one of them resembles the well-known planar tetracoordinate carbon CAl4 on top of a hexagonal Al@Al6 wheel. Our results show that the CAl4 fragment rotates freely around the central axis. The exceptional stability and fluxionality of CAl11- derive from its particular electron distribution.

Structural transformations in boron clusters induced by metal doping.

In the last decades, experimental techniques in conjunction with theoretical analyses have revealed the surprising structural diversity of boron clusters. Although the 2D to 3D transition thresholds are well-established, there is no certainty about the factors that determine the geometry adopted by these systems. The structural transformation induced by doping usually yields a minimum energy structure with a boron skeleton entirely different from that of the bare cluster. This review summarizes those clusters no larger than 40 boron atoms where one or two dopants show a radical transformation of the structure. Although the structures of these systems are not easy to predict, they often adopt familiar shapes such as umbrella-like, wheel, tubular, and cages in various cases.

Combining an Integrated Sensor Array with Machine Learning for the Simultaneous Quantification of Multiple Cations in Aqueous Mixtures.

The direct quantification of multiple ions in aqueous mixtures is achieved by combining an automated machine learning pipeline with transient potentiometric data obtained from a single miniaturized array of polymeric sensors electrodeposited on a conventional printed circuit board (PCB) substrate. A proof-of-concept system was demonstrated by employing 16 polymeric sensors in combination with features extracted from the transient differential voltages produced by these sensors when transitioning from a reference solution to a test solution, thereby obviating the need for a conventional reference electrode. A tree-based regression model enabled concentrations of various metal cations in pure solutions to be determined in less than 2 min. In a model mixture comprising Al3+, Cu2+, Na+, and Fe3+, the mean relative error was found to depend on the type of ion and varied between 1% for Fe3+ and 44% for Na+ in the concentration range 1-10 mg/L. Overall, a mean relative error of 16% was obtained for quantification of these four ions across a total of 124 tests in different solutions spanning concentrations between 2 and 360 mg/L. These results demonstrate how the analytical capability of a multiselective sensor array can leverage data-driven approaches through training by examples for accelerated testing and can be proposed to complement traditional analytical tools to meet industrial demands, including traceability of chemicals.

Planar Hypercoordinate Carbons in Alkali Metal Decorated CE3 2- and CE2 2- Dianions.

After exploring the potential energy surfaces of Mm CE2 p (E=S-Te, M=Li-Cs, m=2, 3 and p=m-2) and Mn CE3 q (E=S-Te, M=Li-Cs, n=1, 2, q=n-2) combinations, we introduce 38 new global minima containing a planar hypercoordinate carbon atom (24 with a planar tetracoordinate carbon and 14 with a planar pentacoordinate carbon). These exotic clusters result from the decoration of V-shaped CE2 2- and Y-shaped CE3 2- dianions, respectively, with alkali counterions. All these 38 systems fulfill the geometrical and electronic criteria to be considered as true planar hypercoordinate carbon systems. Chemical bonding analyses indicate that carbon is covalently bonded to chalcogens and ionically connected to alkali metals.

Magnetically Induced Ring-Current Strengths of Planar and Nonplanar Molecules: New Insights from the Pseudo-π Model.

The pseudo-π model yields current densities and induced magnetic fields that mimic the π-component, allowing investigations of large molecular structures, whether they are planar or not, at a low computational cost but with high accuracy. Herein the π-contribution to the magnetically induced current densities and induced magnetic fields of large planar molecules and nonplanar molecules (such as [10]cyclophenacene and chiral toroidal nanotubes C2016 and C2196) were computed using the pseudo-π model with the gauge-including magnetically induced currents method. Additionally, we provide a way to determine the π-component of the ring-current strengths, which can be used for assessing the aromatic character of large carbon molecules.

Planar tetracoordinate fluorine atoms.

Among the list of planar tetracoordinate atoms, fluorine is missing. So far, there are no theoretical or experimental reports suggesting their existence. Herein, we introduce the first six combinations (FIn4 +, FTl4 +, FGaIn3 +, FIn2Tl2 +, FIn3Tl+, and FInTl3 +) whose global minima contain a planar tetracoordinate fluorine. The bonding analyses indicate that the interactions between the fluorine and the peripheral atoms are significantly electrostatic, which is also reflected in the electronic delocalization. As opposed to other planar tetracoordinate systems with carbon, nitrogen, or oxygen atoms, the fluorine in the ptFs does not act as a σ-acceptor, restraining any back-donation. On the other hand, σ-electrons show a diatropic response, which would characterize these clusters as σ-aromatic.

Planar Tetracoordinate Carbons in Allene-Type Structures.

The exhaustive exploration of the potential energy surfaces of CE2M2 (E = Si-Pb; M = Li and Na) revealed seven global minima containing a planar tetracoordinate carbon (ptC). The design, based on a π-localization strategy, resulted in a ptC with two double bonds forming a linear or a bent allene-type E═C═E motif. The magnetic response of the bent E═C═E fragments support a σ-aromaticity. The bonding analysis indicated that the ptCs form C-E covalent bonds and C-M electrostatic interactions.

Planar Hexacoordinate Carbons: Half Covalent, Half Ionic.

Herein, the first global minima containing a planar hexacoordinate carbon (phC) atom are reported. The fifteen structures belong to the CE3 M3 + (E=S-Te and M=Li-Cs) series and satisfy both geometric and electronic criteria to be considered as a true phC. The design strategy consisted of replacing oxygen in the D3h  CO3 Li3 + structure with heavy and less electronegative chalcogens, inducing a negative charge on the C atom and an attractive electrostatic interaction between C and the alkali-metal cations. The chemical bonding analyses indicate that carbon is covalently bonded to three chalcogens and ionically connected to the three alkali metals.

Head to Tail Distortion Wave Characterizes the Enantiomerization of Helicenes.

A fresh look on helicenes' enantiomerization process with a focus on ring conformation reveals that it can be described as a step-by-step mechanism in which maximal distortion is consecutively transferred along the helicene skeleton, head to tail. Density functional theory methods were used to compute the enantiomerization pathway, and continuous symmetry measures were applied to quantify the distortion of even-number helicenes with 8-14 rings. Our findings show that the distortion wave is additive-the process always starts from one edge of the helicene and progresses along the rings until the other edge is reached. As more rings are added to the helicene, extra steps are appended to the distortion wave. Implications of this fundamental process are discussed in light of similar natural phenomena from polymer dynamics to snake locomotion.

Planar pentacoordinate silicon and germanium atoms.

The global minimum of XMg4Y- (X = Si, Ge; Y = In, Tl) and SiMg3In2 contains a planar pentacoordinate atom of group 14 other than carbon. Its design is based on the "localization" approach, replacing one or two peripheral atoms in XMg52- by more electronegative ones. This change diminishes the repulsion and leads to stronger covalent X-Y bonds, stabilizing the planar pentacoordinate atom species.

Structural effects of alkali-metals on the B12 skeleton.

After an exhaustive exploration of the potential energy surface of B12E- and B12E2 (E = Li-Cs) systems, it was found that for the anionic series, a cage-type and a quasi-planar structure (very similar to the naked B12 cluster) compete to be the putative global minimum. For neutral systems, competition arises between the quasi-planar cluster and a double-ring with the alkali-metals on the highest-symmetry axis. The chemical bonding analyses show that for the entire series, the interaction, predominantly electrostatic, is essentially indistinguishable regardless of the alkali-metal and insufficient for determining the isomeric preference. The isomerization energy decomposition analysis (IEDA) reveals that in the anions, the structural change in the lighter complexes is possible because of the relatively low energy required for the boron skeleton deformation, as opposed to the case of heavy metals. In the case of the neutral systems, the factor determining one isomer over the other corresponds to that of the energy deformation of the alkali-metal dimer.

Delocalization in Substituted Benzene Dications: A Magnetic Point of View.

In this work, the induced magnetic field is analyzed for a series of substituted benzenes dications with formula C6R62+ (R=I, At, SeH, SeCH3, TeH, TeCH3), presumably exhibiting concentric aromaticity. Previous studies concluded that in the carbon skeleton, just π-electrons are delocalized. However, our results support that both the σ- and π-electrons are delocalized in the carbon skeleton, combined with a σ-delocalization in the external ring. The role of the relativistic effects in these dications is discussed in detail.