Search

This study delves into the intriguing realm of chalcogen-bonding interactions, specifically focusing on tellurium(II) and/or tellurium(IV) interactions with iodide species within six crystals. Utilising comprehensive computational chemistry calculations and underpinned by crystallographic data retrieved from the Cambridge Structural Database, this research elucidates the supramolecular aggregation, bonding nature and interaction energetics of Te...I non-covalent bonds in a series of crystals containing each of tellurium(II), tellurium(IV) and iodide. The investigation encompasses a variety of molecular assemblies, ranging from zero-dimensional to complex three-dimensional architectures. Tellurium(II) atoms formed Te...I interactions in six of the crystals but tellurium(IV) participated in Te...I interactions in only three crystals despite there being equal numbers of tellurium(II) and tellurium(IV) atoms in the zero- and onedimensional assemblies. Several computational tools, including Molecular Electrostatic Potential (MEP) surfaces, Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses, provide a nuanced understanding of the electron density topology and charge transfer mechanisms. In some assemblies, where the Te...I interactions are ~3.2 Å, the interaction energies are very large, i.e. 25.6 to 38.8 kcal mol-1, suggesting partial covalent character, an observation corroborated by the NBO analysis; longer Te...I separations correlate with reduced energies, i.e. 3.1 to 7.0 kcal mol-1. Crucially, it is noteworthy that the Te...I interactions identified in this study are distinctly characterised as chalcogen bonds, rather than halogen bonds. [ABSTRACT FROM AUTHOR]

As(III) S‐adenosylmethionine methyltransferases, pivotal enzymes in arsenic metabolism, facilitate the methylation of arsenic up to three times. This process predominantly yields trivalent mono‐ and dimethylarsenite, with trimethylarsine forming in smaller amounts. While this enzyme acts as a detoxifier in microbial systems by altering As(III), in humans, it paradoxically generates more toxic and potentially carcinogenic methylated arsenic species. The strong affinity of As(III) for cysteine residues, forming As(III)‐thiolate bonds, is exploited in medical treatments, notably in arsenic trioxide (Trisenox®), an FDA‐approved drug for leukemia. The effectiveness of this drug is partly due to its interaction with cysteine residues, leading to the breakdown of key oncogenic fusion proteins. In this study, we extend the understanding of As(III)′s binding mechanisms, showing that, in addition to As(III)−S covalent bonds, noncovalent O⋅⋅⋅As pnictogen bonding plays a vital role. This interaction significantly contributes to the structural stability of the As(III) complexes. Our crystallographic analysis using the PDB database of As(III) S‐adenosylmethionine methyltransferases, augmented by comprehensive theoretical studies including molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analysis, emphasizes the critical role of pnictogen bonding in these systems. We also undertake a detailed evaluation of the energy characteristics of these pnictogen bonds using various theoretical models. To our knowledge, this is the first time pnictogen bonds in As(III) derivatives have been reported in biological systems, marking a significant advancement in our understanding of arsenic's molecular interactions. [ABSTRACT FROM AUTHOR]

Combining computations and X-ray structure analysis we have demonstrated that [Pt(CN4)]2− can behave as a Lewis acid inside an enzyme's cavity. The nature of a counterintuitive contact found between a catalytically active GLN residue belonging to a mitochondrial synthase and the Pt(II) center was investigated by combining molecular dynamics and quantum mechanics calculations. Results confirm the electron acceptor role of [Pt(CN4)]2−, serving as an inspiration for the design of biomolecular cages able to tweak the nucleophilic/electrophilic character of an organometallic compound. [ABSTRACT FROM AUTHOR]

The Cambridge Structural Database was surveyed for crystals featuring Hg⋯S secondary-bonding interactions for mercury(II) compounds (excluding organomercury compounds). In all, 43 examples of crystals including intermolecular Hg⋯S interactions operating largely in isolation from other directional interactions were detected with the Hg⋯S interactions within zero-, one- and two-dimensional aggregation patterns. Over 50% of the aggregates are one-dimensional with topologies ranging from linear, zigzag and helical chains, and ribbons to tapes; 30% of the crystals exhibit zero-dimensional aggregates. Crucially, selected examples were subjected to DFT calculations with mapping of the molecular electrostatic potentials (MEPs) of the molecules as well as quantum theory of atoms in molecules (QTAIM), non-covalent interaction plot (NCIPLOT) and natural bond order (NBO) investigations. This study confirms the presence of σ-/π-holes or positive belts at the mercury atom depending on the coordination geometry, defined by covalently and non-covalently bound donor atoms. In molecules coordinated by sulphur donors, the σ-hole at the sulphur atom merges with the positive belt around the mercury atoms, assisting in the formation of spodium bonds and providing higher directionality. The QTAIM/NCIPLOT analysis supports both the existence and non-covalent nature of the spodium bonds. Finally, the NBO analysis reveals charge transfer effects indicating the existence of LP → σ* orbital interactions in the studied molecules; LP is a lone-pair. The energy of stabilisation provided by spodium bonds ranges from a low 3 kcal mol−1 to a high 19 kcal mol−1, i.e. values often greater than those by conventional hydrogen-bonding interactions. [ABSTRACT FROM AUTHOR]

Unraveling the binding preferences involved in the formation of a supramolecular complex is key to properly understand molecular recognition and aggregation phenomena, which are of pivotal importance to biology. The halogenation of nucleic acids has been routinely carried out for decades to assist in their X-ray diffraction analysis. The incorporation of a halogen atom on a DNA/RNA base not only affected its electronic distribution, but also expanded the noncovalent interactions toolbox beyond the classical hydrogen bond (HB) by incorporating the halogen bond (HalB). In this regard, an inspection of the Protein Data Bank (PDB) revealed 187 structures involving halogenated nucleic acids (either unbound or bound to a protein) where at least 1 base pair (BP) exhibited halogenation. Herein, we were interested in disclosing the strength and binding preferences of halogenated A···U and G···C BPs, which are predominant in halogenated nucleic acids. To achieve that, computations at the RI-MP2/def2-TZVP level of theory together with state of the art theoretical modeling tools (including the computation of molecular electrostatic potential (MEP) surfaces, the quantum theory of "Atoms in Molecules" (QTAIM) and the non-covalent interactions plot (NCIplot) analyses) allowed for the characterization of the HB and HalB complexes studied herein. [ABSTRACT FROM AUTHOR]

In this manuscript substituent effects in several silicon tetrel bonding (TtB) complexes were investigated at the RI-MP2/def2-TZVP level of theory. Particularly, we have analysed how the interaction energy is influenced by the electronic nature of the substituent in both donor and acceptor moieties. To achieve that, several tetrafluorophenyl silane derivatives have been substituted at the meta and para positions by several electron donating and electron withdrawing groups (EDG and EWG, respectively), such as –NH2, –OCH3, –CH3, –H, –CF3 and –CN substituents. As electron donor molecules, we have used a series of hydrogen cyanide derivatives using the same EDGs and EWGs. We have obtained the Hammett's plots for different combinations of donors and acceptors and in all cases we have obtained good regression plots (interaction energies vs. Hammet's σ parameter). In addition, we have used the electrostatic potential (ESP) surface analysis as well as the Bader's theory of atoms in molecules (AIM) and noncovalent interaction plot (NCI plot) techniques to further characterize the TtBs studied herein. Finally, a Cambridge Structural Database (CSD) inspection was carried out, retrieving several structures where halogenated aromatic silanes participate in tetrel bonding interactions, being an additional stabilization force of their supramolecular architectures. [ABSTRACT FROM AUTHOR]

A hyperresponsive tool to assess supramolecular catalysis, the cyclization of di‐epoxides into cyclic ethers is used to elucidate the difference between pnictogen‐bonding and Lewis acid catalysis systematically. For all stereoisomers, most tested catalysts follow the Baldwin rules. Brønsted acid and anion–π catalysis afford almost only Baldwin products. Lewis acids such as SbCl3, BF3 and BiCl3 give the poorest selectivity, with at least 50 % Baldwin (B) products for all stereoisomers. In clear contrast, optimized pnictogen‐bonding catalysts operating on the Sb(III) and the Sb(V) level give the fused anti‐Baldwin (A) bicycles as the main product of trans epoxides, independent of syn or anti relation of the two epoxides. In the cis series, Sb(III) pnictogen‐bonding catalysts afford BA products almost exclusively for syn diastereomers, while anti diastereomers give equal amounts of BA and AB products. Sb(V) pnictogen‐bonding catalysts show similarly special trends. These unique characteristics support that pnictogen‐bonding catalysis differs from Lewis acid catalysis and can arguably be defined as its non‐covalent counterpart, just like hydrogen‐bonding catalysis is understood and appreciated as the non‐covalent counterpart of Brønsted acid catalysis. Computational studies on the origin of anti‐Baldwin selectivity reveal Sb(V) catalysts with an introvert deep σ hole surrounded by an almost planar ring of ligands. Central pnictogen‐bond attraction against peripheral steric repulsion then forces the epoxide to break open. In contrast, transient antimony oxidation in cyclic intermediates accounts for the chemoselectivity of Sb(III) catalysts. Presumably due to insufficient accessibility of their σ holes, the activity of tetrel‐bonding catalysts is negligible. The division between powerful pnictogen‐bonding and irrelevant tetrel‐bonding catalysts does not exist with the respective orthodox Lewis acids and thus supports that σ‐hole and Lewis acid catalysis are not the same. [ABSTRACT FROM AUTHOR]

The term matere bond has been recently used to refer to an attractive noncovalent interaction between any element of group 7 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. The utilization of metals such as σ-hole donors is starting to attract the attention of the scientific community. In this manuscript, a comparison between matere bonds and well-known σ-hole interactions (halogen and chalcogen bonds) is carried out using three X-ray structures, retrieved from the Cambridge structural database (CSD), and density functional theory calculations (DFT). The novelty of this work resides in the utilization of a neutral Re(VII) system as the matere bond donor and multivalent chalcogen and halogen donors. In fact, as far as our knowledge extends, the description of σ-hole interactions in Se(VI) is unprecedented in the literature. The σ-hole interactions in Re(VII), Se(VI) and Cl(VII) electron acceptors are analyzed and compared using several computational tools. [ABSTRACT FROM AUTHOR]

In this study we propose to coin the term Wolfium bond (WfB) to refer to a net attractive force (noncovalent interaction) between any element of group 6 and electron donor atoms (neutral molecules or anions) and to differentiate it from a coordination bond (metal‐ligand interaction). We provide evidence of the existence of this interaction by inspecting the X‐ray crystal structure of proteins containing Molybdopterin and Tungstopterin cofactors from the Protein Data Bank (PDB). The plausible biological role of the interaction as well as its physical nature (antibonding Wf‐Ligand orbital involved) are also analyzed by means of ab initio calculations (RI‐MP2/def2‐TZVP level of theory), Atoms in Molecules (AIM), Natural Bond Orbital (NBO) and Noncovalent Interactions plot (NCIplot) analyses. [ABSTRACT FROM AUTHOR]

We report high-level ab initio calculations (CCSD(T)(full)/CBS//SCS-RI-MP2(full)/aug-cc-pwCVTZ) that demonstrate the importance of cooperativity effects when Anion–π and CH/π interactions are simultaneously established with benzene as the π-system. In fact, most of the complexes exhibit high cooperativity energies that range from 17% to 25.3% of the total interaction energy, which is indicative of the strong influence of the CH/π on the Anion–π interaction and vice versa. Moreover, the symmetry-adapted perturbation theory (SAPT) partition scheme was used to study the different energy contributions to the interaction energies and to investigate the physical nature of the interplay between both interactions. Furthermore, the Atoms in Molecules (AIM) theory and the Non-Covalent Interaction (NCI) approach were used to analyze the two interactions further. Finally, a few examples from the Protein Data Bank (PDB) are shown. All results stress that the concurrent formation of both interactions may play an important role in biological systems due to the ubiquity of CH bonds, phenyl rings, and anions in biomolecules. [ABSTRACT FROM AUTHOR]

Osme bonds have been recently defined as the attractive interaction between an element of group 8 acting as an electrophile and any atom or group of atoms acting as a nucleophile. To date, the known examples of osme bonds in X-ray structures involve mostly the highly reactive OsO4 and amines and amine oxides. In this work, evidence supporting the existence of osme bonds in osmium(VI) derivatives is reported. In particular, nitrido-osmium(VI) complexes that present square-pyramidal geometries are well disposed to participate in osme bonds opposite to the Os≡N bond. By using a combination of experimental and theoretical results, the existence and importance of this new class of σ-hole interactions is demonstrated in the solid state of several nitrido-osmium(VI) derivatives. [ABSTRACT FROM AUTHOR]

This feature article highlights the discovery and development of phosphanoxyl complex chemistry starting from (neutral) low-coordinate phosphorus radicals and the quest of metal ligation effects. We describe synthesis and reactions of precursors, namely 2,2,6,6-tetramethylpiperidinoxyl (TEMPO) substituted phosphane tungsten(0) complexes. Trapping reactions of transient phosphanoxyl complexes, formed via thermal homolytic N–O bond cleavage, as well as their use in radical polymerisations are illustrated, thus revealing an interesting reactivity dichotomy. DFT calculations provide insight into thermal stabilities of precursors and the resulting spin density distributions (SDDs) in these reactive intermediates. Systematic studies on the dependance of the electron delocalisation in phosphanoxyl complexes have been performed examining different substitution pattern at phosphorus and different co-ligand combinations at the tungsten(0) center. Preliminary results on Mn and Fe complexes are reported. [ABSTRACT FROM AUTHOR]

In this study the ability of metal coordinated Chalcogen (Ch) atoms to undergo Chalcogen bonding (ChB) interactions has been evaluated at the PBE0-D3/def2-TZVP level of theory. An initial CSD (Cambridge Structural Database) inspection revealed the presence of square planar Pd/Pt coordination complexes where divalent Ch atoms (Se/Te) were used as ligands. Interestingly, the coordination to the metal center enhanced the σ-hole donor ability of the Ch atom, which participates in ChBs with neighboring units present in the X-ray crystal structure, therefore dictating the solid state architecture. The X-ray analyses were complemented with a computational study (PBE0-D3/def2-TZVP level of theory), which shed light into the strength and directionality of the ChBs studied herein. Owing to the new possibilities that metal coordination offers to enhance or modulate the σ-hole donor ability of Chs, we believe that the findings presented herein are of remarkable importance for supramolecular chemists as well as for those scientists working in the field of solid state chemistry. [ABSTRACT FROM AUTHOR]

Introduction: Electrogram (EGM) fractionation is often associated with diseased atrial tissue; however, mechanisms for fractionation occurring above an established threshold of 0.5 mV have never been characterized. We sought to investigate during sinus rhythm (SR) the mechanisms underlying bipolar EGM fractionation with high‐density mapping in patients with atrial fibrillation (AF). Methods: Forty‐five patients undergoing AF ablation (73% paroxysmal, 27% persistent) were mapped at high density (18562 ± 2551 points) during SR (Rhythmia). Only bipolar EGMs with voltages above 0.5 mV were considered for analysis. When fractionation (> 40 ms and >4 deflections) was detected, we classified the mechanisms as slow conduction, wave‐front collision, or a pivot point. The relationship between EGM duration and amplitude, and tissue anisotropy and slow conduction, was then studied using a computational model. Results: Of the 45 left atria analyzed, 133 sites of EGM fragmentation were identified with voltages above 0.5 mV. The most frequent mechanism (64%) was slow conduction (velocity 0.45 m/s ± 0.2) with mean EGM voltage of 1.1 ± 0.5 mV and duration of 54.9 ± 9.4 ms. Wavefront collision was the second most frequent (19%), characterized by higher voltage (1.6 ± 0.9 mV) and shorter duration (51.3 ± 11.3 ms). Pivot points (9%) were associated with the highest degree of fractionation with 70.7 ± 6.6 ms and 1.8 ± 1 mV. In 10 sites (8%) fractionation was unexplained. The EGM duration was significantly different among the 3 mechanisms (p =.0351). Conclusion: In patients with a history of AF, EGM fractionation can occur at amplitudes > 0.5 mV when in SR in areas often considered not to be diseased tissue. The main mechanism of EGM fractionation is slow conduction, followed by wavefront collision and pivot sites. [ABSTRACT FROM AUTHOR]

In this work we report structural and computational studies of favipiravir, which is now used as a drug for COVID-19 treatment. The molecule is completely flat and stabilized by an intramolecular O–H···O hydrogen bond, yielding a six-membered pseudo-aromatic ring. The aromaticity index of this pseudo-aromatic ring was found to be 0.748, while the same indix for the pyrazine ring in favipiravir was found to be 0.954. The crystal packing of favipiravir is mainly constructed through intermolecular N–H···O, N–H···N and C–H···O hydrogen bonds, yielding a 3D supramolecular framework with a zst topology defined by the point symbol of (65·8). The crystal structure of favipiravir is further stabilized by weak C–F···F–C intermolecular type II dihalogen interactions, yielding a 1D supramolecular polymeric chain. More than 80% of the total Hirshfeld surface area for favipiravir is occupied by H···H/C/N/O/F and C···N/O contacts. Energy frameworks have been calculated to additionally analyze the overall crystal packing. It was established that the structure of favipiravir is mainly characterized by the dispersion energy framework followed by the less significant electrostatic energy framework contribution. Finally, by using density functional theory (DFT) calculations and the quantum theory of atoms in molecules, we have assigned the interaction energy of each hydrogen bond, which can be helpful to develop scoring functions to be used in force fields/docking calculations. [ABSTRACT FROM AUTHOR]

The important role of spodium bonding (SpB) in Zn(II) and Cd(II) complexes is highlighted in this feature article. SpB has been recommended to distinguish coordination bonds (high covalent character) from non-covalent contacts. Here, two new d10-metal dithiophosphate complexes, [M(L)2]2 {where M = Zn (1) and Cd (2); L = O,O′-bis(4-tert-butylphenyl) phosphorodithioate} have been synthesized in purely aqueous media and characterized by elemental and spectral analyses. The X-ray crystallography analyses indicate that both complexes are dinuclear, in which each metal atom is coordinated with four sulfur atoms in a distorted tetrahedral environment containing two four-membered chelate rings joined to a central eight-membered ring through metal (Zn/Cd) atoms. In complex 1 the eight-membered ring possesses a "saddle" conformation located on a two-fold axis of symmetry, C2, while in complex 2 it possesses a centrosymmetric "twisted chair" conformation, Ci. In addition, the oxygen and sulfur atoms belonging to the bridging ligands form intramolecular SpBs with Zn(II) in 1 and Cd(II) in 2. The existence of intramolecular SpBs in both complexes is evidenced by DFT calculations by using the Bader's Quantum Theory of Atoms-in-Molecules (QTAIM) combined with the non-covalent interaction plot (NCI plot) index that is based on the reduced density gradient (NCI-RDG) method. A Hirshfeld surface study has been carried out to understand the intermolecular contacts in the crystal lattice. [ABSTRACT FROM AUTHOR]

Premature ventricular complexes (PVCs) are increasingly recognized, as the use of ECG wearables becomes more widespread. In particular, PVCs arising from both the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) comprise the majority of these arrhythmias and form a significant component of an electrophysiology practice. A keen understanding of the correlative anatomy of the outflow tracts, in addition to recognizing key ECG indices illustrating PVC sites of origin, are fundamental in preparing for a successful ablation. Patient selection, incorporating symptomatology, structural disease, and PVC burden can pose a challenge, though tools such as the ABC‐VT risk score may help identify those patients with a higher risk of clinical deterioration. Utilizing intracardiac echocardiography to highlight salient anatomic features not visible with fluoroscopy allows for a more precise and safer ablation. Interpretation of intracardiac EGMs, and the careful examination for low amplitude highly fractionated pre‐potentials, enhanced by the advent of new developed mapping/ablation catheters, remains crucial. Utilizing these tools will guide the electrophysiologist to an efficient and effective outflow tract PVC ablation. [ABSTRACT FROM AUTHOR]

Herein we report experimental evidence for the shortest intermolecular distance reported for two electronically-different hydrogen atoms in the solid state. The Hδ+⋯Hδ− non-covalent interaction was studied using theoretical calculations indicating that electrostatic and dispersion forces are of paramount importance. [ABSTRACT FROM AUTHOR]

In this study, Fe3O4 nanoparticles (FeNPs) decorated with halogenated perylene diimides (PDIs) have been used for capturing VOCs (volatile organic compounds) through noncovalent binding. Concretely, we have used tetrachlorinated/brominated PDIs as well as a nonhalogenated PDI as a reference system. On the other hand, methanol, ethanol, propanol, and butanol were used as VOCs. Experimental studies along with theoretical calculations (the BP86-D3/def2-TZVPP level of theory) pointed to two possible and likely competitive binding modes (lone pair–π through the π-acidic surface of the PDI and a halogen bond via the σ-holes at the Cl/Br atoms). More in detail, thermal desorption (TD) experiments showed an increase in the VOC retention capacity upon increasing the length of the alkyl chain, suggesting a preference for the interaction with the PDI aromatic surface. In addition, the tetrachlorinated derivative showed larger VOC retention times compared to the tetrabrominated analog. These results were complemented by several state-of-the-art computational tools, such as the electrostatic surface potential analysis, the Quantum Theory of Atoms in Molecules (QTAIM), as well as the noncovalent interaction plot (NCIplot) visual index, which were helpful to rationalize the role of each interaction in the VOC···PDI recognition phenomena. [ABSTRACT FROM AUTHOR]

It is often said that pnictogen‐bonding catalysis, and σ‐hole catalysis in general, would not work in aqueous systems because the solvent would interfere as an overcompetitive pnictogen‐bond acceptor. In this study, we show that the transfer of pnictogen‐bonding catalysis from hydrophobic solvents to aqueous systems is possible by replacing only hydrophobic with hydrophilic substrates, without changing catalyst or reaction. This differs from conventional covalent Lewis acid catalysts, which are instantaneously destroyed by ligand exchange. With their water‐proof substituents in place of exchangeable ligands, pnictogen‐bonding catalysts, the supramolecular counterpart of Lewis acid catalysts, are evinced to catalyze transfer hydrogenation of quinolines in neutral aqueous systems. To secure these results, we introduce a water‐soluble fluorogenic substrate that releases a coumarin upon the reduction of quinolines instead of activated quinolidiniums, and stiborane catalysts with deepened σ holes. They demonstrate that pnictogen‐bonding catalysts can operate in higher‐order architectures for supramolecular systems catalysis under biologically relevant conditions, and provide an operational assay for high‐throughput catalyst screening by fluorescence imaging, in situ under relevant aqueous conditions. [ABSTRACT FROM AUTHOR]

In this manuscript we evaluate the X-ray structure of five new pertechnetate derivatives of general formula [M(H2O)4(TcO4)2], M=Mg, Co, Ni, Cu, Zn (compounds 1-5) and one perrhenate compound Zn(H2O)4(ReO4)2 (6). In these complexes the metal center exhibits an octahedral coordination with the pertechnetate units as axial ligands. All compounds exhibit the formation of directional Tc···O Matere bonds (MaBs) that propagate the [M(H2O)4(TcO4)2], into 1D supramolecular polymers in the solid state. Such 1D polymers are linked, generating 2D layers, by combining additional MaBs and hydrogen bonds (HBs). Such concurrent motifs have been analyzed theoretically, suggesting the noncovalent s-hole nature of the MaBs. The interaction energies range from weak (~ - 2 kcal/mol) for the MaBs to strong (~ - 30 kcal/mol) for the MaB+HB assemblies, where HB dominates. In case of M=Zn, the corresponding perrhenate Zn(H2O)4(ReO4)2 complex, has been also synthesized for comparison purposes, resulting in the formation of an isostructural Xray structure, corroborating the structure-directing role of Matere bonds. [ABSTRACT FROM AUTHOR]

Arrhythmogenic cardiomyopathy (ACM) is a heart disease characterized by a fibrotic replacement of myocardial tissue and a consequent predisposition to ventricular arrhythmic events, especially in the young. Post-mortem studies and the subsequent diffusion of cardiac MRI have shown that left ventricular involvement in arrhythmogenic cardiomyopathy is common and often develops early. Regarding the arrhythmic risk stratification, the current scores underestimate the arrhythmic risk of patients with arrhythmogenic cardiomyopathy with left involvement. Indeed, the data on arrhythmic risk stratification in this group of patients are contradictory and not exhaustive, with the consequence of not correctly identifying patients at a high arrhythmic risk who deserve protection from arrhythmic death. We propose a literature review on arrhythmic risk stratification in patients with ACM and left involvement to identify the main features associated with an increased arrhythmic risk in this group of patients. [ABSTRACT FROM AUTHOR]

Homoleptic [L−I−L]+ iodine(I) complexes (where L is a R3R2R1N tertiary amine) were synthesized via the [L−Ag−L]+→ [L−I−L]+ cation exchange reaction. In solution, the amines form [R3R2R1N−Ag−NR1R2R3]+ silver(I) complexes, which crystallize out from solution as the meso‐[L−Ag−L]+complexes, as characterized by X‐ray crystallography. The subsequent [L−I−L]+ iodine(I) analogues were extremely reactive and could not be isolated in the solid state. Density functional theory (DFT) calculations were performed to study the Ag+−N and I+−N interaction energies in silver(I) and iodine(I) complexes, with the former ranging from −80 to −100 kJ mol−1 and latter from −260 to −279 kJ mol−1. The X‐ray crystal structures revealed Ag+⋅⋅⋅Cπ and Ag+⋅⋅⋅H−C short contacts between the silver(I) cation and flexible N‐alkyl/N‐aryl groups, which are the first of their kind in such precursor complexes. [ABSTRACT FROM AUTHOR]

Three homoleptic Hg(S2CNR2)2, for R = ethyl (1), isobutyl (2), and cyclohexyl (3), compounds apparently exhibit a steric-dependent supramolecular association in their crystals. The small group in 1 allows for dimer formation via covalent Hg–S interactions through an eight-membered {–HgSCS}2 ring as the dithiocarbamato ligands bridge centrosymmetrically related Hg atoms; intradimer Hg···S interactions are noted. By contrast, centrosymmetrically related molecules in 2 are aligned to enable intermolecular Hg···S interactions, but the separations greatly exceed the van der Waals radii. The large group in 3 precludes both dimerization and intermolecular Hg···S interactions. Computational chemistry indicates that the potential region at the Hg atom is highly dependent on the coordination geometry about the Hg atom. Intramolecular (1) and intermolecular (2) spodium bonding (SpB) is demonstrated. Even at separations approaching 0.4 Å beyond the sum of the assumed van der Waals radii, the energy of the stabilization afforded by the structure directs SpB in 2 amounts to approximately 2.5 kcal/mol. A natural bond orbital (NBO) analysis points to the importance of the LP(S) → σ*(Hg–S) charge transfer and to the dominance of the dispersion forces and electron correlation to the SpB in 2. [ABSTRACT FROM AUTHOR]

In this study, a series of electron donor (–NH2, –NMe2 and –tBu) and electron-withdrawing substituents (–F, –CN and –NO2) were used to tune the nucleophilicity or electrophilicity of a series of square planar Ni2+, Pd2+ and Pt2+ malonate coordination complexes towards a pentafluoroiodobenzene and a pyridine molecule. In addition, Bader's theory of atoms in molecules (AIM), noncovalent interaction plot (NCIplot), molecular electrostatic potential (MEP) surface and natural bond orbital (NBO) analyses at the PBE0-D3/def2-TZVP level of theory were carried out to characterize and discriminate the role of the metal atom in the noncovalent complexes studied herein. We hope that the results reported herein may serve to expand the current knowledge regarding these metals in the fields of crystal engineering and supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Retraction of 'Nucleophilic iodonium interactions (NIIs) in 2-coordinate iodine(I) and silver(I) complexes' by Jas S. Ward et al., Chem. Commun., 2021, 57, 5094–5097, DOI: 10.1039/D1CC01505B. [ABSTRACT FROM AUTHOR]

The reactivity of biological or synthetic metalloenzymes is modulated in the presence of redox innocent Lewis acidic metal ions as they change the redox potential of the redox active metal ions present in the active site of metalloenzymes. To study this effect, we synthesised a mono-nuclear V(IV) complex (VOL, 1) with an N2O4 donor bicompartmental ligand, characterized it by single-crystal X-ray crystallography and recorded its cyclic voltammogram in acetonitrile. The CV revealed a reversible redox process for the V(IV)/V(V) couple. The potential of the V(IV)/V(V) couple shifted to a more positive value when equivalent amounts of Li+, Na+, K+, Mg2+, Ca2+ and Ba2+ ions were added separately to its acetonitrile solution, but the extent of shift for Li+ and Mg2+ was much less than that of the other metal ions. The guest metal ions except Li+ and Mg2+ were accommodated in the outer compartment of VOL as confirmed by IR and UV-Vis spectral analysis. Single-crystal structural analysis of [(VOL)KPF6]2, (1·K) and [(VOL)Ba (ClO4)2(H2O)]n, (1·Ba) also confirmed the hetero-metallic adduct formation. The correlation of the shift of the V(IV/V) redox potential with the Lewis acidity of respective metal ions deviated appreciably from linearity. DFT calculations suggest that the shift in potential is probably controlled by local electric fields induced by those ions, as indicated by 2D vector electric field maps. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and X‐ray structures of three α,β "two wall" aryl‐extended calix[4]pyrroles having either identical (symmetrically substituted) or different (non‐symmetrically substituted) meso‐aryl substituents (aryl=4‐ethynylphenyl and 4‐iodophenyl) are reported. The X‐ray structure of the co‐crystal formed by the two symmetrically substituted calix[4]pyrroles is also described. In the solid state, all studied α,β‐calix[4]pyrroles exhibit a 1,3‐alternate conformation with two co‐crystallized acetonitrile solvent molecules H‐bonded to adjacent cis‐pyrrole rings. Remarkably, the 1,3‐conformer of the non‐symmetrically substituted iodophenyl/ethynylphenyl compound is intrinsically chiral. The two enantiomers are present in the average asymmetric unit in a 65 : 35 occupancy ratio displaying a head‐to‐tail directional disorder. This is due to the functional complementarity and the isosteric and isoelectronic properties of the para‐substituents: iodo and ethynyl. That is, the negative belt of iodine is similar to the negative π‐system of the C≡C triple bond and the σ‐hole in the iodine atom is similar to the positive proton at the C≡C−H group. [ABSTRACT FROM AUTHOR]

• Theoretical and CSD study of Sb•••Te noncovalent bonds. • Pnictogen-Chalcogen bonding competition at both ends of the Te–Sb bond. • QTAIM, NCIPlot and ELF characterization of Sb•••Te interactions. In this manuscript a curious behavior observed in the solid state of several X-ray structures retrieved from the Cambridge structural database (CSD) is described and analyzed. These structures have in common the presence of a metalloid–metalloid pnictogen (Pn)–chalcogen (Ch) covalent bond (i.e., Sb–Te bond) in the structure. The Sb–Te bond presents different σ-holes at both ends of the bond in terms of size and intensity. These compounds have a tendency to form short intermolecular Sb•••Te interactions in the solid state. The aim of this work is to investigate, by using dispersion-corrected density functional theory (DFT-D3) calculations, whether the Sb•••Te contacts observed in the solid state correspond to PnB (Sb is the Lewis acid) or ChB (Te is the Lewis acid). Moreover, using two model stibanyl telluranes, the interaction energies with a series of Lewis bases and anions using both ends of the Sb–Te covalent bond have been computed to investigate which side (PnB or ChB donor) is able to establish stronger interactions with common electron rich atoms. Finally, several computational tools such as the quantum theory of atoms-in-molecules (QTAIM), noncovalent interaction plot (NCIPlot) index and electron localization (ELF) function (2D and 3D maps) have been used to further characterize the physical nature of the Sb•••Te interactions. The results reported herein suggest that in the Sb•••Te contacts the Te atom acts as σ-hole donor and the Sb as electron density donor. [Display omitted]. [ABSTRACT FROM AUTHOR]

In this review, several examples of the application of pnictogen (Pn) (group 15) and chalcogen (Ch) bonding (group 16) interactions in organocatalytic processes are gathered, backed up with Molecular Electrostatic Potential surfaces of model systems. Despite the fact that the use of catalysts based on pnictogen and chalcogen bonding interactions is taking its first steps, it should be considered and used by the scientific community as a novel, promising tool in the field of organocatalysis. [ABSTRACT FROM AUTHOR]

• The syntheses and characterization of two polymeric vanadate chain complexes are reported. • The X-ray data of only complex 2 has been reported. • Both the complexes have a linear vanadate chain, countered by appropriately charged organic amine moieties. • The simplest units of the chains are linear [V 3 O 9 ]3− and [V 2 O 6 ]2− anionic moieties. • One forms trifurcated hydrogen bonds which have been analyzed by DFT calculations and a combination of QTAIM and NCI plot computational tools. They have been compared to the hydrogen bonds formed by the protonated –NH 3 + group in the other one, suggesting the trifurcated hydrogen bonds in the former to be stronger than the more predictable hydrogen bonds in the latter. • Phenoxazinone synthase like activity of complex 2 shows moderate catalytic activity towards the oxidation of o -aminophenol by aerial oxygen. Two polymeric [VO 3 ] n n− metavanadate chain complexes have been synthesized and characterized by spectral and elemental analysis. The X-ray data of only complex 2 has been reported in this work. Both the complexes have a linear vanadate chain, countered by appropriately charged organic amine moieties. The simplest units of the chains contain a linear [V 3 O 9 ]3− and [V 2 O 6 ]2− anionic moieties in complexes 1 and 2 , respectively. The charge neutralizing cationic counterparts are triprotonated tren {tris(2-aminoethyl)amine} and a diprotonated N-ethylethylenediamine in complexes 1 and 2 , respectively. Complex 2 is unique in the sense that its crystal lattice contains the divanadate [V 2 O 6 ]2− repeat unit and protonated N-ethylethylenediamine as the charge compensating and space filling moiety which is not reported in any other literature till now. The individual units are assembled to form a 2D supramolecular network. DFT calculations (PBE0-D3/def2-TZVP) have been used in combination to QTAIM and NCI plot computational tools to analyze the strong N–H···O charge assisted hydrogen bonding interactions in both complexes. Phenoxazinone synthase like activity (i.e. oxidative conversion of o -aminophenol to 2-aminophenoxazine-3-one) of complex 2 was evaluated. Two [VO 3 ] n n− metavanadate chain complexes have been synthesized and characterized by standard spectroscopic and X-ray analyses. Both the complexes exhibit polyanionic vanadate chain, counterbalanced by appropriately charged organic amine moieties. One forms trifurcated hydrogen bonds that have been analyzed by DFT calculations and a combination of QTAIM and NCI Plot computational tools. They have been compared to the hydrogen bonds formed by the other species, revealing that the trifurcated hydrogen bonds in the former are stronger than the more conventional hydrogen bonds in the latter. [Display omitted] [ABSTRACT FROM AUTHOR]

The co-crystallization of S-(CF3)-dibenzothiophenium ("Umemoto" – abbreviated Ume) cations and polycyanometalates with different coordination geometries yields a large structural variety of supramolecular assemblies. In the case of [Ume+]2[Ni(CN)4]2−·CH2Cl2 all four cyanide groups of the square-planar dianion act as chalcogen bond acceptors whereas the sulfur atoms of the Umemoto cations act as biaxial chalcogen bond donors. For tetrahedral [Zn(CN)4]2− a more complex assembly of four Umemoto cations and two dianions is observed. In the case of [Ume+]3[Fe(CN)6]3−·CH2Cl2 one Umemoto cation even acts as a triaxial chalcogen bond donor whereas only 4 out of the 6 cyanide groups act as chalcogen bond acceptors. For [Ume+]3[W(CN)8]3− a polymeric chain structure is observed in which all Umemoto cations act as biaxial chalcogen bond donors. DFT investigations focus on the physical nature of the chalcogen bonds, encompassing energetic assessments, MEP surface plots, QTAIM, and NBO analysis, shedding light on the nature of chalcogen donor–acceptor interactions. The energetic results evidence that total contributions of chalcogen bonds in different synthons range from −7.6 to −16.3 kcal mol−1, surpassing that of hydrogen bonds that range from −4.9 to −11.8 kcal mol−1. [ABSTRACT FROM AUTHOR]

A new doubly carboxylato-bridged Co(II) dinuclear complex, [Co(bdtbpza)(NCS)]2 (1), was obtained in a satisfactory yield by employing a 'scorpionate'-type precursor, bdtbpza {bis-(3,5-di-tert-butylpyrazol-1-yl)acetate}, and was then structurally characterized. Single-crystal X-ray diffraction analysis revealed that, in 1, each Co(II) is penta-coordinated, leading to a distorted trigonal–bipyramidal geometry within the coordination environment of N3O2. Weak antiferromagnetic coupling within the Co(II) ions in 1 was found based on the isotropic spin Hamiltonian H = −J(S1·S2) for the Si = 3/2 system. For evaluating the spin density distribution and the mechanism for the magnetic exchange coupling, DFT analysis was performed, with the calculated result agreeing the experimental magnetic data. A study into electrochemical H2 evolution, involving cyclic voltammetry (CV), controlled potential electrolysis (CPE), and gas chromatographic (GC) analyses of the graphite electrode modified with the cobalt complex in a neutral aqueous solution revealed the high catalytic activity of the complex with a low overpotential toward H2O reduction. The faradaic efficiency of the catalyst was found to be 83.7% and the di-cobalt catalyst-modified electrode displayed quite an interesting H2-evolution activity compared with that of bare electrodes. These results are encouraging for the future potential application of 1 in water splitting. [ABSTRACT FROM AUTHOR]

With the increase in demand of electronic devices in the modern civilization, research in material science is being projected to grow in faster rate. In this facet, coordination polymer (CP) based electronic device is one of the promising candidates to the material researchers. Herein, two new Zn(II) and Cd(II) based one‐dimensional (1D) CPs, denoted as [Zn(4‐avp)2(5‐nip)] ⋅ (solvent)x (1) and [Cd(4‐avp)(5‐nip)(CH3OH)] (2) have been synthesized using relatively less explored highly conjugated polycyclic aromatic hydrocarbon (PAH) based monodentate ligand, 4‐[2‐(9‐anthryl)vinyl]pyridine (4‐avp) and bidentate linker 5‐nitroisophthalic acid (H25‐nip). In this instance, the CP 1 creates 1D chain polymer, while CP 2 is made up with 1D ladder polymer. It is interesting to note that both the CPs exhibit semiconducting nature and generate metal‐semiconductor (MS) junction Schottky barrier diodes (SBDs). However, Cd‐based CP 2 shows higher charge transport as compared to Zn‐CP 1, which could be due to stronger π⋅⋅⋅π contacts as well as larger size of Cd metal in CP 2. The experimental results are well corroborated with theoretical density of states (DOS) calculations. [ABSTRACT FROM AUTHOR]

Two coordination complexes [Ni(Hpydco)2(bpy)] (1) and [Ni(pydco)(phen)(H2O)2]·4.5H2O 0.5CH3OH (2) have been synthesized using a mixed-ligand system including pyridine-2,5-dicarboxylic acid N-oxide (H2pydco) as an O-donor ligand and 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) as a chelating N-donor ligand and NiCl2.6H2O as a source for Ni ions. The crystal structures of 1 and 2 form discrete complexes in which extensive π−π stacking interactions between aromatic rings of the N-donor ligands resulted in the formation of one dimensional (1D) chain-like structures. The chains are connected by hydrogen bonds to expand the structures into 2D-supramolecular networks. Hirshfeld surface analysis and Density Functional Theory (DFT) calculations were included to rationalize the relative strength of the π-stacking assemblies observed in both complexes. [ABSTRACT FROM AUTHOR]

Four lead(II) complexes featuring pyrazoylisonicotinoylhydrazone ligand paired with various anionic co-ligands (azido, thiocyanato, nitrito, and nitrato) were synthesized and thoroughly examined using structural, analytical, and spectroscopic techniques. These ligands, in their mono-deprotonated state, bind to the lead(II) ion in a tridentate manner through two nitrogen atoms and one oxygen atom. Single-crystal X-ray crystallography revealed the capacity of these molecular complexes to form larger aggregates influenced by the nature of the anion attached to the metal center. In every complex, the lead atom adopts a hemidirectional coordination environment, making it geometrically suited for tetrel bond formation. The crystal structures demonstrate that lead atoms engage in notably short interactions with nitrogen atoms, distances that are shorter than the sum of their van der Waals radii yet exceed the sum of their covalent radii. These tetrel bonds play a pivotal role in weaving the monomeric into self-assembled dimers or extended supramolecular 1D polymers. The formation and characteristics of these intriguing supramolecular structures observed in the solid state of each complex were further explored and validated through density functional theory (DFT) calculations and several computational tools like MEP, NCIPlot, QTAIM, and ELF methods. [ABSTRACT FROM AUTHOR]

The reaction between 5-acetylbarbituric acid and 4-dimethylthiosemicarbazide or 4-hexamethyleneiminyl thiosemicarbazide produces 5-acetylbarbituric-4-dimethylthiosemicarbazone (H2AcbDM) and 5-acetylbarbituric-4N-hexamethyleneiminyl thiosemicarbazone (H2Acbhexim). Eight new complexes with different copper(II) salts have been prepared and characterized using elemental analysis, molar conductance, UV–Vis, ESI-HRMS, FT-IR, magnetic moment, EPR, and cyclic voltammetry. In addition, three-dimensional molecular structures of [Cu(HAcbDM)(H2O)2](NO3)·H2O (3a), [Cu(HAcbDM)(H2O)2]ClO4 (4), and [Cu(HAcbHexim)Cl] (6) were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out. The H-bonded assemblies were further studied energetically using DFT calculations and MEP surface and QTAIM analyses. In these complexes, the thiosemicarbazone coordinates to the metal ion in an ONS-tridentate manner, in the O-enolate/S-thione form. The electrochemical behavior of the thiosemicarbazones and their copper(II) complexes has been investigated at room temperature using the cyclic voltammetry technique in DMFA. The Cu(II)/Cu(I) redox system was found to be consistent with the quasi-reversible diffusion-controlled process. [ABSTRACT FROM AUTHOR]

The chemistry of light dipnictenes has been widely investigated in the last century with remarkable achievements especially for azobenzene derivatives. In contrast, distibenes and dibismuthenes are relatively rare and show very limited reactivity. Herein, we have designed a protocol using visible light to enhance the reactivity of heavy dipnictenes. Exploiting the distinctive π–π* transition, we have been able to isolate unique examples of dipnictene‐cobalt complexes. The reactivity of the distibene complex was further exploited using red light in the presence of a diazoolefin to access an unusual four‐membered bicyclo[1.1.0]butane analog, containing only a single carbon atom. These findings set the bases to a conceptually new strategy in heavy element double bonds chemistry where visible light is at the front seat of bond activation. [ABSTRACT FROM AUTHOR]

Two new Mn(II) and Zn(II) metal–organic compounds of 1,10-phenanthroline and methyl benzoates viz. [Mn(phen)2Cl2]2-ClBzH (1) and [Zn(4-MeBz)2(2-AmPy)2] (2) (where 4-MeBz = 4-methylbenzoate, 2-AmPy = 2-aminopyridine, phen = 1,10-phenanthroline, 2-ClBzH = 2-chlorobenzoic acid) were synthesized and characterized using elemental analysis, TGA, spectroscopic (FTIR, electronic) and single crystal X-ray diffraction techniques. The crystal structure analysis of the compounds revealed the presence of various non-covalent interactions, which provides stability to the crystal structures. The crystal structure analysis of compound 1 revealed the formation of a supramolecular dimer of 2-ClBzH enclathrate within the hexameric host cavity formed by the neighboring monomeric units. Compound 2 is a mononuclear compound of Zn(II) where flexible binding topologies of 4-CH3Bz are observed with the metal center. Moreover, various non-covalent interactions, such as lp(O)-π, lp(Cl)-π, C–H∙∙∙Cl, π-stacking interactions as well as N–H∙∙∙O, C–H∙∙∙O and C–H∙∙∙π hydrogen bonding interactions, are found to be involved in plateauing the molecular self-association of the compounds. The remarkable enclathration of the H-bonded 2-ClBzH dimer into a supramolecular cavity formed by two [Mn(phen)2Cl2] complexes were further studied theoretically using density functional theory (DFT) calculations, the non-covalent interaction (NCI) plot index and quantum theory of atoms in molecules (QTAIM) computational tools. Synergistic effects were also analyzed using molecular electrostatic potential (MEP) surface analysis. [ABSTRACT FROM AUTHOR]

This work reports a combined computational and experimental analysis of the ability of square planar d8 transition metal complexes to establish unconventional halogen bonding interactions with chloro-, bromo-, and iodopentafluorobenzene as σ-hole donors. Typical M⋯Ha (M = transition metal and Ha = halogen) interactions are coordination bonds (frequently halides acting as counter ions) or semicoordination bonds (neutral lone pair donor halogens). However, in recent times a new binding mode has been described in the literature with a reverse donor–acceptor role. That is, directional C–Br,I⋯M halogen bonding (HaB) interactions have been reported where the metal center acts as the electron-rich atom and the halogen atom acts as the acceptor via its σ-hole. In addition to the Cambridge Structural Database (CSD) survey of exemplifying X-ray structures, this manuscript reports a DFT study that investigates the relative ability of Ni, Pd, and Pt square planar complexes to participate in HaBs with chloro-, bromo-, and iodopentafluorobenzene. [ABSTRACT FROM AUTHOR]

The hooked cross-shaped anion, [Cu(N3)4]2−, in the pentanuclear hetero-metallic copper(II)–sodium complex, [(CuLNa)2(μ-N3)2Cu(N3)2] (1), where H2L = N,N′-bis(3-ethoxysalicylidene)-2,2-dimethylpropane-1,3-diamine (N2O4 donor compartmental Schiff base) is nearly planar and provides a π-basic surface adequate for establishing non-covalent interactions in the solid state as an electron donor. This unit participates in strong CH⋯[Cu(N3)4]2− interactions on both sides of the molecular plane. They have been analyzed using DFT calculations and MEP analysis and characterized using NCI plot index analysis along with π-stacking interactions involving the aromatic and chelate rings of the Na, Cu-coordinated Schiff base ligand. Finally, cation–π interactions between the pentacoordinated Na-atom and the aromatic ring of the Schiff base ligand are described and compared with two X-ray structures retrieved from the CSD. These unconventional interactions are important for the packing of 1, particularly CH⋯[Cu(N3)4]2− that has not been studied before, as far as our knowledge extends. [ABSTRACT FROM AUTHOR]

This manuscript shows that chalcogen bonding (ChB) interactions are enhanced by the coordination of the chalcogen atom to metal centers as evidenced using DFT calculations (PBE0-D3/def2-TZVP level of theory). X-ray structures retrieved from the Cambridge Structural Database (CSD) are used to support the enhanced ability of Se and Te-atoms coordinated to transition metals to participate in ChBs, eliminating the necessity to use strong electron-withdrawing groups bonded to the Ch atom. Orbital analysis performed using the natural bond orbital (NBO) technique discloses a large LP → σ* contribution, especially for anionic electron donors. In one example, the new σ-hole that is generated upon complexation (opposite to the Ch--M bond) plays a crucial role in the solid state, promoting the formation of infinite 1D polymers. [ABSTRACT FROM AUTHOR]

A new heterocyclic ligand, N3L [4-(1-methylimidazole)-2,6-di(pyrazinyl)pyridine] has been synthesized and characterized by several spectroscopic methods. The ligand (N3L) was then used for the preparation of two complexes, namely, [Cu(N3L)Cl2] (complex 1) and [Cu(N3L)(Cl)(μ-ONO2)]n (complex 2). The crystal structures of these complexes have been established by single-crystal X-ray diffraction analysis. Complex 1 is a mononuclear one whereas complex 2 is a 1D coordination polymer. The structural insights reveal that non-classical hydrogen bonding (C–H⋯Cl, C–H⋯O, C–H⋯N) and π⋯π stacking interactions play a crucial role in stabilizing various supramolecular architectures of the title complexes in the solid state. All the non-classical hydrogen bonding interactions are quantified through the infographic 2D fingerprint plots. Additionally, theoretical calculations (density functional theory) were carried out for both complexes to analyze these non-covalent interactions in the solid state including their characterization using Bader's theory of atoms in molecules and the noncovalent interaction (NCI) plot index. [ABSTRACT FROM AUTHOR]

A new Cd(II) derivative, [Cd(2-Hstp)(Hbipy)2] (1), was obtained hydrothermally by the combination of Cd(NO3)2·4H2O as metal salt, the flexible aromatic carboxylate, 2-sulfoterephthalic acid (2-stp), and the N-donor ancillary ligand, 4,4′-bipyridine (bipy), as organic linker. Single crystal X-ray diffraction analysis revealed the molecular structure of the complex, in which the Cd(II) atoms show a distorted octahedral geometry. In the asymmetric unit, both the carboxylate and the N-donor connector bridge pairs of cadmium ions; this ultimately leads to the formation of a set of undulated sheets formed by fused rings comprising six cadmium centers, two bipy, and four 2-stp ligands. Considering each complex as a node, the supramolecular structure can be seen as a 6-c uninodal net of the type pcu, with point symbol {412.63} and vertex symbol [4.4.4.4.4.4.4.4.4.4.4.4.*.*.*]. The Cd(II) derivative endowed the material with moderate luminescent properties. Finally, the molecular geometry of 1 has been studied by DFT computation applying the B3LYP/def2-SVP level of theory. [ABSTRACT FROM AUTHOR]

A bent trinuclear zinc complex, [Zn{ZnIL}2]·DMF {H2L = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)]bis[6-methoxyphenol]}, was synthesized and characterized using standard spectroscopic methods and X-ray diffraction analysis. The existence of coordinated amino groups and iodide counter ions provides the system with strong H-bond donor and acceptor groups that dictate the formation of 1D supramolecular assemblies in the solid state. These have been analysed using Hirshfeld surface analysis and DFT calculations. Dimerization energies have been found to be very large for the homodimer and the heterodimer, extracted from the infinite 1D chain. They have also been characterized and rationalized using molecular electrostatic potential (MEP) and non-covalent interaction plot (NCI plot) computational tools. Finally, the Cambridge Structural Database (CSD) has been analysed to compare the assemblies observed in [Zn{ZnIL}2]·DMF with those already published to resolve confusion on the NH⋯I interactions. [ABSTRACT FROM AUTHOR]

New 1–2 nm macrocyclic iodine(I) complexes prepared VIA a simple ligand exchange reaction manifest rigid 0.5–1 nm cavities that bind the hexafluorophosphate anion in the gas phase. The size of the cavities and the electrostatic interactions with the iodine(I) cations influence the anion binding properties of these macrocyclic complexes. [ABSTRACT FROM AUTHOR]

The X-ray structure of 2-(dibromomethyl)benzonitrile, featuring unexpectedly short C≡N⋯Br halogen bond distances between a nitrile group and a C(sp3)-linked bromine atom, is presented. Despite the weak Lewis base nature of the nitrile N atom and absence of strong electron-withdrawing groups on the Br atom, π-stacking significantly enhances both the electron donor and acceptor capability of the interacting partners. As such, and beyond trivial (hetero)aromatic systems, the rationale of C ≡N⋯B r halogen bonding can also be employed in purely aliphatic systems. [ABSTRACT FROM AUTHOR]

Kinases are enzymes that play a critical role in governing essential biological processes. Due to their pivotal involvement in cancer cell signaling, they have become key targets in the development of anti‐cancer drugs. Among these drugs, those containing the 2,4‐dihalophenyl moiety demonstrated significant potential. Here we show how this moiety, particularly the 2‐fluoro‐4‐iodophenyl one, is crucial for the structural stability of the formed drug‐enzyme complexes. Crystallographic analysis of reported kinase‐inhibitor complex structures highlights the role of the halogen bonding that this moiety forms with specific residues of the kinase binding site. This interaction is not limited to FDA‐approved MEK inhibitors, but it is also relevant for other kinase inhibitors, indicating its broad relevance in the design of this class of drugs. [ABSTRACT FROM AUTHOR]

Two new metal–organic multi-component compounds of Ni(II) and Co(II), viz. [Ni(3-CNpy)2(H2O)4]ADS·2.75H2O (1) and [Co(3-CNpy)2(H2O)4](4-ClbzSO3)2 (2) (3-CNpy = 3-cyanopyridine, ADS = anthraquinone-1,5-disulfonate, 4-ClbzSO3 = 4-chlorobenzenesulfonate), were synthesized and characterized using single crystal XRD, TGA, spectroscopic (IR, electronic) and elemental analyses. Both the compounds crystallize as multi-component compounds of Ni(II) and Co(II), with uncoordinated ADS and 4-ClbzSO3 moieties in the crystal lattice, respectively. Crystal structure analyses revealed the presence of antiparallel nitrile···nitrile and π-stacked assemblies involving alternate coordinated 3-CNpy and uncoordinated ADS and 4-ClbzSO3 moieties. Moreover, unconventional charge reverse Cl∙∙∙N halogen bonding contacts observed in compound 2 provide additional reinforcement to the crystal structure. Theoretical calculations confirm that the H-bonding interactions, along with anion–π(arene) and anion–π(CN) in 1 and π–π, antiparallel CN···CN and charge reverse Cl···N halogen bonds in 2, play crucial roles in the solid state stability of the compounds. In vitro anticancer activities observed through the trypan blue cell cytotoxicity assay reveal that the compounds induce significant concentration dependent cytotoxicity in Dalton's lymphoma (DL) cancer cells, with nominal effects in normal healthy cells. Molecular docking studies reveal that the compounds can effectively bind with the active sites of anti-apoptotic proteins, which are actively involved in cancer progression. [ABSTRACT FROM AUTHOR]

Three new PbII complexes [Pb(LI)(SCN)]n, {[Pb(LII)](SCN)}n and {[Pb(HLIII)(SCN)](SCN)}n (HLI = N′-phenyl(pyridin-2-yl)methylene-N-phenylthiosemicarbazide, HLII = N′-amino(pyrazin-2-yl)methylenethiosemicarbazide, HLIII = N′-amino(pyridin-2-yl)methylenethiosemicarbazide) have been synthesized and characterized by spectroscopic techniques and single crystal X-ray diffraction. In all complexes, the corresponding organic ligand behaves as a tridentate N,N′,S-chelating species. A 1D supramolecular polymeric aggregation in complex [Pb(LI)(SCN)]n is dictated by the Pb⋯NCS and Pb⋯S＝C tetrel bonds formed between the [Pb(LI)(SCN)] species. 1D cationic coordination polymers ([Pb(LII)])nn+ in the structure of complex {[Pb(LII)](SCN)}n are linked into a 2D supramolecular polymeric layer through the Pb⋯NCS tetrel bonds and Pb⋯π(NCS) interactions formed with the nitrogen atom and the conjugated system of the free SCN− anions, respectively. The cationic species [Pb(HLIII)(SCN)]+ in the structure of complex {[Pb(HLIII)(SCN)](SCN)}n produce a 1D supramolecular polymer due to the Pb⋯SCN and Pb⋯S＝C tetrel bonds, further stabilized by the Pb⋯π(NCS) interactions formed with the conjugated system of the coordinated NCS− anion. The latter anions also link these 1D chains through the Pb⋯SCN tetrel bonds, yielding 1D supramolecular polymeric ribbons. The energetic relevance of the Pb⋯S and Pb⋯N tetrel bonds has been studied by DFT calculations. The tetrel bonds have been characterized using QTAIM and NCIplot analysis and rationalized using molecular electrostatic potential surface calculations. [ABSTRACT FROM AUTHOR]