Search

The response of the crystallographic structure of iodic acid has been determined using neutron diffraction up to 7.2 GPa. We observe no evidence of a direct structural phase transition. However, we do observe evidence of a molecular re-orientation, previously suggested by a high pressure experimental Raman study and computational study. We show how the crystal structure responds to the application of pressure and observe an increased extent of the halogen-bonding interactions. [ABSTRACT FROM AUTHOR]

The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methylpyridines or dimethylpyridines, X = Cl or Br) are presented: trichlorido(2-methylpyridine)gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tribromido(2-methylpyridine)gold(III), [AuBr3(C6H7N)], 2; tribromido(3-methylpyridine)gold(III), [AuBr3(C6H7N)], 3; tribromido(2,4-dimethylpyridine)gold(III), [AuBr3(C7H9N)], 4; trichlorido(3,5-dimethylpyridine)gold(III), [AuCl3(C7H9N)], 5; tribromido(3,5-dimethylpyridine)gold(III), [AuBr3(C7H9N)], 6, and trichlorido(2,6-dimethylpyridine)gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z′ = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z′ = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the ‘HKLF 5’ method. The largest interplanar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au—N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au—X)2, with antiparallel Au—X bonds linked by Au...X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary interactions (Au...X or X...X contacts, `weak' C—H...X hydrogen bonds) to form chain, double chain (`ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C—H...Cl hydrogen bonds combined with Cl...Cl contacts (1b) or Cl...π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1–8.

Anisotropy is crucial for birefringence (Δn) in optical materials, but optimizing it remains a formidable challenge (Δn >0.3). Supramolecular frameworks incorporating π‐conjugated components are promising for achieving enhanced birefringence because of their structural diversity and inherent anisotropy. Herein, we first synthesized (C6H6NO2)+Cl− (NAC) and then constructed a halogen‐bonded supramolecular framework I+(C6H4NO2)− (INA) by halogen aliovalent substitution of Cl− with I+. The organic moieties are protonated and deprotonated nicotinic acid (NA), respectively. The antiparallel arrangement of birefringent‐active units in NAC and INA leads to significant differences in the bonding characteristics between the interlayer and intralayer domains. Moreover, the [O⋅⋅⋅I+⋅⋅⋅N] halogen bond in 1D [I+(C6H4NO2)−] chain exhibits stronger interactions and stricter directionality, resulting in a more pronounced in‐plane anisotropy between the intrachain and interchain directions. Consequently, INA exhibits exceptional birefringent performance, with a value of 0.778 at 550 nm, twice that of NAC (0.363 at 550 nm). This value significantly exceeds those of commercial birefringent crystals, such as CaCO3 (0.172 at 546 nm), and is the highest reported value among ultraviolet birefringent crystals. This work presents a novel design strategy that employs halogen bonds as connection sites and modes for birefringent‐active units, opening new avenues for developing high‐performance birefringent crystals. [ABSTRACT FROM AUTHOR]

The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methyl­pyridines or di­methyl­pyridines, X = Cl or Br) are presented: tri­chlorido­(2-methyl­pyridine)­gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tri­bromido­(2-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 2; tri­bromido­(3-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 3; tri­bromido­(2,4-di­meth­yl­pyridine)­gold(III), [AuBr3(C7H9N)], 4; tri­chlorido­(3,5-di­methylpyridine)­gold(III), [AuCl3(C7H9N)], 5; tri­bromido­(3,5-di­methyl­pyridine)­gold(III), [AuBr3(C7H9N)], 6, and tri­chlorido­(2,6-di­methyl­pyridine)­gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z′ = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z′ = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the ‘HKLF 5’ method. The largest inter­planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au—N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au—X)2, with anti­parallel Au—X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter­actions (Au⋯X or X⋯X contacts, `weak' C—H⋯X hydrogen bonds) to form chain, double chain (`ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C—H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts (1b) or Cl⋯π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1–8. [ABSTRACT FROM AUTHOR]

The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methyl­pyridines or di­methyl­pyridines, X = Cl or Br) are presented: tri­chlorido­(2-methyl­pyridine)­gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tri­bromido­(2-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 2; tri­bromido­(3-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 3; tri­bromido­(2,4-di­meth­yl­pyridine)­gold(III), [AuBr3(C7H9N)], 4; tri­chlorido­(3,5-di­methylpyridine)­gold(III), [AuCl3(C7H9N)], 5; tri­bromido­(3,5-di­methyl­pyridine)­gold(III), [AuBr3(C7H9N)], 6, and tri­chlorido­(2,6-di­methyl­pyridine)­gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z′ = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z′ = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the 'HKLF 5' method. The largest inter­planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au--N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au--X)2, with anti­parallel Au--X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter­actions (Au X or X X contacts, 'weak' C--H⋯X hydrogen bonds) to form chain, double chain ('ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C--H⋯Cl hydrogen bonds combined with Cl Cl contacts (1b) or Cl π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1-8. [ABSTRACT FROM AUTHOR]

Empirical force field methods typically rely on point charges to describe the electrostatic interactions, which is problematic when anisotropy needs to be considered, as in the case of the electrostatic potential of covalently bound halogens that possess a positive site, termed σ -hole, surrounded by a large negative belt. To address this, an off-center point charge (extra point, EP) is usually placed at a given distance from the halogen to emulate the σ -hole and commonly used implementations are based on the restrained electrostatic potential (RESP) procedure to fit atomic charges, being one of the most used charge models. In this context, no specific Merz–Singh–Kollman (MK) radius for iodine is available in the literature, which is an essential parameter in the RESP fitting procedure. In this work, we explored the impact of the iodine MK radius on the obtained RESP charges for a set of 12 iodinated molecules. We verified that the relative root mean square (RRMS) values obtained with and without an EP kept decreasing with increasing radii for most compounds, thus impairing optimization using such a procedure. Nevertheless, the use of an iodine MK radius lower than 2 Å is not advisable since the RRMS kept decreasing considerably until this value was reached. Moreover, the performance of three iodine MK radii was studied with the estimation of the free energy of hydration (Δ G hyd) values using alchemical free energy calculations, which are particularly sensitive to the charges used. Despite the usage of different radii not leading to remarkable differences, our results indicate that using a value of 2.70 Å leads to lower mean absolute errors (MAE) and root mean squared error (RMSE) values when comparing the calculated with the experimental Δ G hyd values. Restrained Electrostatic Potential (RESP) charges are commonly used in force fields and Merz-Singh-Kollman (MK) radii are needed in the fitting. Since iodine radius is not available, in this work, we explored the impact of changing the iodine MK radius on the RESP charges of a set of 12 iodinated molecules and their hydration free energy predictions. Our results indicate that, although the changes are small, a value of 2.70 Angstrom leads to a better agreement with experimental values. [ABSTRACT FROM AUTHOR]

The syntheses and structures of dimethyl [11,21:24,31‐terphenyl]‐14,34‐dicarboxylate (1), dimethyl 22,25‐diiodo[11,21:24,31‐terphenyl]‐14,34‐dicarboxylate (2), potassium [11,21:24,31‐terphenyl]‐14,34‐dicarboxylate (3) and dimethyl [1,1′‐biphenyl]‐4,4′‐dicarboxylate (4) are reported. Neighboring phenyl rings in compounds 1, 3 and 4 have a planar structure (torsion angles are 0.6–4.1°) and the molecules are packed into regular layers. In the structure of the iodinated derivative of terphenyldicarboxylic acid (2), the middle benzene ring of the terphenyl fragment is rotated relative to the other rings by 64° due to the repulsion between the protons and the iodine atoms of neighboring rings. The formation of halogen bonds between iodine and oxygen atoms of the carbonyl group leads to the movement of molecules of one layer into another layer and the loss of layered structure. Potassium [11,21:24,31‐terphenyl]‐14,34‐dicarboxylate (3) forms crystals with an ionic structure. The coordination number of the potassium cation is eight and the resulting coordination polyhedron is a distorted square antiprism. Dianions in the potassium salt crystal are packed in layers similar to the layers in the dimethyl ethers 1 and 4. Salt 3 has high thermal stability to 500°C. [ABSTRACT FROM AUTHOR]

Various functional groups have been considered as acceptors for halogen bonds, but the oxime functionality has received very little attention in this context. In this study, we focus on the analysis of the hydrogen and halogen bond preferences observed in the crystal structures of 5-halogeno-1H-isatin-3-oximes. These molecules can be involved in various non-covalent interactions, and the competition between these interactions has a decisive influence on their self-organization. In particular, we were interested to see whether the crystal structures of 5-halogeno-1H-isatin-3-oximes, especially bromine- and iodine-substituted ones, are characterized by the presence of halogen bonds formed with the oxime functionality. The oxime group proved its ability to compete with the other strong donor and acceptor sites by participating in the formation of cyclic hydrogen-bonded heterosynthons oxime∙∙∙amide and Ooxime∙∙∙Br/I halogen bonds. [ABSTRACT FROM AUTHOR]

The reactions of zinc(II) bromide with 3- and 4-iodobenzonitriles (3-I-BzCN and 4-I-Bz-CN) afford heteroligand complexes [L2ZnBr2] (L = 3-I-BzCN (I) and 4-I-BzCN (II)), whose structures are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2253175 (I) and 2253176 (II)). Both crystal structures contain halogen bonds I···Br linking the [ZnBr2L2] fragments into supramolecular layers (I) or chains (II). The energies of these noncovalent interactions are estimated by quantum-chemical calculations. [ABSTRACT FROM AUTHOR]

An extension of the use of the linear response function to interpret non-covalent interactions is put forward. Due to its computational intricacies, most applications until now have been done on isolated atoms or molecules using coupled perturbed Hartree–Fock or Kohn–Sham theory, thereby adopting the simplest level for the LRF evaluation, the independent particle approximation. The previously presented possibilities for extension (the random phase and the "full" expression) are scrutinised, thereby highlighting the intricacies in the evaluation of the exchange-correlation term in the case of meta-GGAs and hybrid functionals, and implemented. A set of 25 hydrogen bonded and 11 halogen bonded systems, selected from Hobza S66 and X 40 compilations, were used to investigate the correlation between the stabilisation energy due to these non-covalent interactions and the relevant atom–atom-condensed LRF matrix element. The lack of a relevant correlation in the case of hydrogen bonding is contrasted with the excellent result for the halogen bonds. The correlation between the full option and the IPA is high providing support for our previous work using the IPA as is also the case for the previously used iterative Hirshfeld condensation and the more advanced FOHI method making use of fractional occupation numbers. The fundamental difference between hydrogen and halogen bond behaviour and the retrieval of the stability sequence within the halogen bonds series are traced back to the nature of the LRF as a response function for perturbations in the external potential putting polarisation effects and the polarisability of the atoms of the donor–acceptor couple at the forefront. The extension to the use of the softness kernel is advocated and already invoked to rectify the behaviour of two deviating complexes involving S as second row halogen bond acceptor atom. [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]

Radical translocation reactions are finding various uses in organic synthesis, in particular the stereospecific formation of complex natural products. In this work, the syntheses and single-crystal structures of two substituted 2-iodo-phenyl methyl-amides are reported, namely cyclo-propane carboxylic acid (2-iodo-phenyl)-methyl-amide, C11H12INO (1), and cyclo-heptane carboxylic acid (2-iodo-phenyl)-methyl-amide, C15H20INO (2). In each case, the methyl-amide group has a syn conformation, and this grouping is perpendicular to the plane of the benzene ring: these solid-state conformations appear to be well setup to allow an intramolecular hydrogen atom transfer to take place as part of a radical translocation reaction. Short intermolecular I⋯O halogen bonds occur in each crystal structure, leading to [010] chains in 1 [I⋯O = 3.012 (2) Å] and isolated dimers in 2 [I⋯O = 3.024 (4) and 3.057 (4) Å]. The intermolecular interactions are further quantified by Hirshfeld surface analyses.

The analysis of crystal structures of SF5 - or SF4 -containing molecules revealed that these groups are often surrounded by hydrogen or other fluorine atoms. Even though fluorine prefers F⋅⋅⋅H over F⋅⋅⋅F contacts, the latter appeared to be important in many compounds. In a significant number of datasets, the closest F⋅⋅⋅F contacts are below 95 % of the van der Waals distance of two F atoms. Moreover, a number of repeating structural motifs formed by contacts between SF5 groups was identified, including different supramolecular dimers and infinite chains. Among SF4 -containing molecules, the study focused on SF4 Cl compounds, including the first solid-state structure analyses of these reactive species. Additionally, electrostatic potential surfaces of a series of Ph-SF5 derivatives were calculated, pointing out the substituent influence on the ability of F⋅⋅⋅X contact formation (X=F or other electronegative atom). Interaction energies were calculated for different dimeric arrangements of Ph-SF5 , which were extracted from experimental crystal structure determinations.

Radical translocation reactions are finding various uses in organic synthesis, in particular the stereospecific formation of complex natural products. In this work, the syntheses and single-crystal structures of two substituted 2-iodo-phenyl methyl-amides are reported, namely cyclo-propane carboxylic acid (2-iodo-phenyl)-methyl-amide, C11H12INO (1), and cyclo-heptane carboxylic acid (2-iodo-phenyl)-methyl-amide, C15H20INO (2). In each case, the methyl-amide group has a syn conformation, and this grouping is perpendicular to the plane of the benzene ring: these solid-state conformations appear to be well setup to allow an intramolecular hydrogen atom transfer to take place as part of a radical translocation reaction. Short intermolecular I⋯O halogen bonds occur in each crystal structure, leading to [010] chains in 1 [I⋯O = 3.012 (2) Å] and isolated dimers in 2 [I⋯O = 3.024 (4) and 3.057 (4) Å]. The intermolecular interactions are further quantified by Hirshfeld surface analyses. [ABSTRACT FROM AUTHOR]

In this manuscript, we have examined the CSD (Cambridge Structural Database) to investigate the relative ability of Te and I (in practice, the heaviest chalcogen and halogen atoms) in di- and tri-iododiorganyltellurium(IV) derivatives to establish σ-hole interactions. The geometry around the Te(IV) in this type of compound is trigonal bipyramidal where the stereoactive lone pair at Te(IV) occupies one of the equatorial positions. In the solid state, Te(IV) tends to form pseudo-octahedral coordination by establishing strong noncovalent interactions opposite to the two covalent bonds of the equatorial plane. Such contacts can also be classified as chalcogen bonds following the recommendation of the International Union of Pure and Applied Chemistry (IUPAC). Such contacts have been analyzed energetically in this work using density functional theory (DFT) calculations, rationalized using molecular electrostatic potential (MEP) surface analysis and characterized using a combination of the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction plot (NCIplot) computational tools. Finally, the observation of halogen bonds and type I halogen···halogen contacts is also emphasized and compared to the chalcogen bonds. Energy decomposition analysis has also been performed to compare the physical nature of chalcogen, halogen and type I interactions. [ABSTRACT FROM AUTHOR]

The heteroligand complexes [(2-Br-5-MePy)2ZnX2] (X = Cl (I), Br (II)) were prepared by the reaction of zinc(II) chloride or bromide with 2-bromo-5-methylpyridine and studied by X-ray diffraction (CCDC nos. 2204966 (I) and 2204967 (II)). The crystals of I and II contain Cl···Br and Br···Br halogen bonds, which connect the [MX2L2] moieties into supramolecular chains. The energies of these noncovalent interactions were estimated using quantum chemical calculations. [ABSTRACT FROM AUTHOR]

While the halogen bond has been recognised and studied for over a hundred years, it is only in more recent times that chemists have begun to apply it and see its possibilities as another supramolecular interaction that can be deployed in the preparation of materials. This review takes one of those areas, liquid crystals, and considers examples of motifs that have been deployed successfully to generate new mesogens. In particular, rather than attempting to be comprehensive, the article reviews critically data from well‐characterised systems and seeks to first make some comparisons with analogous hydrogen‐bonded materials, before considering how the lability and flexibility of the halogen bond expresses itself in liquid crystal behaviour. [ABSTRACT FROM AUTHOR]

Quantum chemical methods were employed to analyze the nature and the origin of the directionality of pnictogen (PnB), chalcogen (ChB), and halogen bonds (XB) in archetypal FmZ⋅⋅⋅F− complexes (Z=Pn, Ch, X), using relativistic density functional theory (DFT) at ZORA‐M06/QZ4P. Quantitative Kohn‐Sham MO and energy decomposition analyses (EDA) show that all these intermolecular interactions have in common that covalence, that is, HOMO−LUMO interactions, provide a crucial contribution to the bond energy, besides electrostatic attraction. Strikingly, all these bonds are directional (i.e. F−Z⋅⋅⋅F− is approximately linear) despite, and not because of, the electrostatic interactions which, in fact, favor bending. This constitutes a breakdown of the σ‐hole model. It was shown how the σ‐hole model fails by neglecting both, the essential physics behind the electrostatic interaction and that behind the directionality of electron‐rich intermolecular interactions. Our findings are general and extend to the neutral, weaker ClI⋅⋅⋅NH3, HClTe⋅⋅⋅NH3, and H2ClSb⋅⋅⋅NH3 complexes. [ABSTRACT FROM AUTHOR]

The structures of six benzene and three naphthalene derivatives involving bromo, bromomethyl and dibromomethyl substituents, namely, 1,3‐dibromo‐5‐(dibromomethyl)benzene, C7H4Br4, 1,4‐dibromo‐2,5‐bis(bromomethyl)benzene, C8H4Br6, 1,4‐dibromo‐2‐(dibromomethyl)benzene, C7H4Br4, 1,2‐bis(dibromomethyl)benzene, C8H6Br4, 1‐(bromomethyl)‐2‐(dibromomethyl)benzene, C8H7Br3, 2‐(bromomethyl)‐3‐(dibromomethyl)naphthalene, C12H9Br3, 2,3‐bis(dibromomethyl)naphthalene, C12H8Br4, 1‐(bromomethyl)‐2‐(dibromomethyl)naphthalene, C12H9Br3, and 1,3‐bis(dibromomethyl)benzene, C8H6Br4, are presented. The packing patterns of these compounds are dominated by Br...Br contacts and C—H...Br hydrogen bonds. The Br...Br contacts, shorter than twice the van der Waals radius of bromine (3.7 Å), seem to play a crucial role in the crystal packing of all these compounds. The occurrence of Type I and Type II interactions is also discussed briefly, considering the effective atomic radius of bromine, as is their impact on the packing of molecules in the individual structures. [ABSTRACT FROM AUTHOR]

Although in terahertz (THz) source materials molecular anions significantly influence the performance of THz generation, only limited classes of molecular counter anions have been reported. Here, utilizing dichlorinated molecular anions in THz generators is reported for the first time, to the best of our knowledge. In these new crystals, two dichlorinated molecular anions with different molecular symmetries, asymmetric 3,4‐dichlorobenzenesulfonate (34DCS) and symmetric 3,5‐dichlorobenzenesulfonate (35DCS), are incorporated with a 2‐(4‐hydroxystyryl)‐1‐methylquinolinium (OHQ) cation possessing top‐level molecular optical nonlinearity. OHQ‐34DCS exhibits a strong nonlinear optical response, in contrast to OHQ‐35DCS. In OHQ‐34DCS crystals, the dichlorinated groups form strong halogen bonds (XBs) and hydrogen bonds (HBs), which are beneficial for suppressing molecular (phonon) vibrations. The optical‐to‐THz conversion efficiency of the OHQ‐34DCS crystals is extremely high, comparable to that of the benchmark organic THz generators. Moreover, the THz emission spectra from the OHQ‐34DCS crystals, compared to those of previously reported benchmark analogous crystals, are stronger modulated toward a flatter shape, but possess substantially reduced spectral dimples. Therefore, the introduction of dichlorinated molecular anions is an efficient approach for the design of highly efficient electro‐optic salt crystals as efficient broadband THz wave sources. [ABSTRACT FROM AUTHOR]

Herein, a simple and efficient strategy that involves dual 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU)/iron‐catalyzed alkene perfluoroalkylvinylation by using perfluoroalkyl iodides and 2‐aminonaphthalene‐1,4‐diones as coupling partners is demonstrated. In terms of the developed catalytic system, various styrenes and aliphatic alkenes are well‐tolerated, leading to the accurate preparation of perfluoroalkyl‐containing 2‐aminonaphthalene‐1,4‐diones in excellent regioselectivity. Moreover, the protocol can be readily applied in late‐stage modifications of natural products and pharmaceuticals. The title reactions are featured by easily accessible and inexpensive catalysts and substrates, broad substrate applicability, and mild reaction conditions. Mechanistic investigations reveal a tandem C−I cleavable alkylation and C−C vinylation enabled by cooperative DBU/iron catalysis. [ABSTRACT FROM AUTHOR]

Reduced nucleophilicities ИB of axially symmetric molecules B were determined from , where De is the equilibrium dissociation energy of the complexes B⋅⋅⋅XY, NB is the nucleophilicity of B, EXY is the electrophilicity of the halogen‐bond donor XY and σmin ${{\sigma }_{{\rm { min}}}{\rm \ }}$ is the minimum electrostatic surface potential of B. The series B⋅⋅⋅ClY, B⋅⋅⋅BrY, B⋅⋅⋅IY (Y=F, Cl, Br, I, CN, and CCH) as well as (B⋅⋅⋅XY, XY=F2, Cl2, Br2,and BrCl) of complexes were investigated. Molecules B were grouped so that the terminal atom involved in the halogen bond was fixed within the group. Groups having N as the terminal atom were RCN (R=CH3, H, and F) or RN (R=N and P), those with C as the terminal atom were RNC (R=H and F) and RC (R=O, S and Se), and those with a terminal O atom were R=C=O (R=O or S). Graphs of De ${{D}_{{\rm { e}}}}$ versus EXY for each group were straight lines through the origin, with generally different gradients, hence implying different NB. By contrast, when De/σmin ${{D}_{{\rm { e}}}/{\sigma }_{{\rm { min}}}}$ was the ordinate the lines conflated to give a single straight line, which then defines a common (reduced) nucleophilicity ИB for that group of B. Hence it was concluded that ИB is an intrinsic property of the terminal atom, independent of the remainder of B, and only weakly dependent on the type (C, N or O) of the terminal atom. Moreover, ИB for each B was the same as determined previously from the hydrogen‐bonded series B⋅⋅⋅HX, (X=F, Cl, Br, I, CN, CCH, and CP). [ABSTRACT FROM AUTHOR]

The halogen bond complexes CF 3 X⋯Y and C 2 F 3 X⋯Y, with Y = furan, thiophene, selenophene and X = Cl, Br, I, have been studied by using DFT and CCSD(T) in order to understand which factors govern the interaction between the halogen atom X and the aromatic ring. We found that PBE0-dDsC/QZ4P gives an adequate description of the interaction energies in these complexes, compared to CCSD(T) and experimental results. The interaction between the halogen atom X and the π -bonds in perpendicular orientation is stronger than the interaction with the in-plane lone pairs of the heteroatom of the aromatic cycle. The strength of the interaction follows the trend Cl < Br < I; the chalcogenide in the aromatic ring nor the hybridization of the C–X bond play a decisive role. The energy decomposition analysis shows that the interaction energy is dominated by all three contributions, viz., the electrostatic, orbital, and dispersion interactions: not one factor dominates the interaction energy. The aromaticity of the ring is undisturbed upon halogen bond formation: the π -ring current remains equally strong and diatropic in the complex as it is for the free aromatic ring. However, the spin-orbit coupling between the singlet and triplet π → π * states is increased upon halogen bond formation and a faster intersystem crossing between these states is therefore expected. [ABSTRACT FROM AUTHOR]

The hydrogen bonding in the Au(I) complex [Au(F ⋅ HF)(SPhos)] (SPhos=dicyclohexyl(2',6'‐dimethoxy[1,1'‐biphenyl]‐2‐yl)phosphane) (1 a ⋅ HF) has been analysed by IR and NMR measurements, revealing the formation of an unsymmetrical bifluoride moiety. The data are in excellent agreement with DFT calculations. Comparisons to analogous complexes bearing NHC (NHC=N‐heterocyclic carbene) ligands demonstrated a comparable bonding situation. The identity of the halogen bond in the compound [Au(F ⋅ IC6F5)(SPhos)] (1 a ⋅ IC6F5) in CD2Cl2 has been estimated, and van't Hoff data for the equilibrium between [Au(F)(SPhos)] (1 a) and IC6F5 with [Au(F ⋅ IC6F5)(SPhos)] are ΔH0=−8.1(3) kJ mol−1 and ΔS0=−36(1) J (mol K)−1. The latter are also in agreement with DFT calculations. For all calculations, comparisons between an explicit and implicit solvent model were drawn. Single crystal X‐ray diffraction studies were performed for [Au(F ⋅ 2IC6F5)(BrettPhos)] ⋅ 2IC6F5 (BrettPhos=2‐(dicyclohexylphosphino)‐3,6‐dimethoxy‐2',4',6'‐triisopropyl‐1,1'‐biphenyl) (1 b ⋅ 4IC6F5) demonstrating the presence of halogen bonds to Au(I) fluorido complexes in the solid state. [ABSTRACT FROM AUTHOR]

Multistep synthetic pathway towards a series of the anisoleboron-capped ribbed-functionalized iron(II) cage complexes was developed. Their hexachloroclathrochelate precursor was obtained by the template condensation of three dichloroglyoximate chelating ligand synthons with two molecules of 4-methoxyphenylboronic acid as a Lewis-acidic cross-linking agent on the iron(II) ion as a matrix. It easily underwent a stepwise nucleophilic substitution with S2- and O2-dinucleophilic aliphatic (ethanedithiolate) or aromatic (pyrocatecholate) agents, forming the stable X2 (X = S or O)-six-membered ribbed substituent(s) at a quasiaromatic cage framework. Performing these reactions under the different reaction conditions (i.e., at various hexachloroclathrochelate-to-nucleophile molar ratios, a wide range of temperatures and a series of the solvents) allowed to control a predominant formation of its mono-, di- or triribbed-substituted macrobicyclic derivatives. Thus obtained iron(II) di- and tetrachloroclathrochelates can undergo their post-synthetic transformations with active nucleophilic agents. The latter complexes underwent a further nucleophilic substitution with the anionic derivative of n-butanthiol, thus giving the hexasulfide macrobicyclic compound with two functionalizing n-alkyl substituents in one of its three chelate α-dioximate fragments and two apical biorelevant anisole substituents. The obtained iron(II) clathrochelates, possessing a low-spin electronic d6 configuration, were characterized using elemental analysis, MALDI-TOF mass spectrometry, UV–Vis, 1H and 13C{1H} NMR spectroscopies, and by the single-crystal X-ray diffraction experiments for the hexachloroclathrochelate precursor, its dichlorotetrasulfide macrobicyclic derivative and the monoribbed-functionalized hexasulfide cage complex. In all their molecules, the encapsulated iron(II) ion is situated in the centre of its FeN6-coordination polyhedron, the geometry of which is intermediate between a trigonal prism and a trigonal antiprism with the distortion angles φ from 21.4 to 23.4°. Halogen bonding between the polyhalogenoclathrochelate molecules in their crystals is observed. [ABSTRACT FROM AUTHOR]

The low ionic conductivity of poly(ethylene oxide) (PEO)-based polymer electrolytes at room temperature impedes their practical applications. The addition of a plasticizer into polymer electrolytes could significantly promote ion transport while inevitably decreasing their mechanical strength. Herein, we report a supramolecular plasticizer (SMP) to break the trade-off effect between ionic conductivity and mechanical properties in PEO-based polymer electrolytes. Accordingly, the SMP is constructed by tetraethylene glycol dimethyl ether (G4) and SbF 3 through halogen bonds. The SMP-plasticized PEO electrolyte (PEO/SMP) presents a simultaneously enhanced ionic conductivity of 2.4 × 10 -4 S cm -1 (25 °C) and a high mechanical strength of 8.1 MPa, compared to those of pristine PEO-based electrolytes. Benefiting from the halogen bonds between G4 and SbF 3 , the Li-O coordination in PEO/SMP is evidently weakened, and thus rapid Li + transport is achieved. Furthermore, the PEO/SMP electrolyte possesses a wide electrochemical stability window of 4.5 V and, importantly, derives an inorganic-rich SEI with a low interfacial resistance on a lithium metal surface. By using PEO/SMP, the lithium-metal battery with the LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode exhibits a good rate and long-term cycling performance with a capacity retention of 75.3% (500 cycles). This work offers a rational guideline for the design of polymer electrolytes suitable for high-performance lithium-metal batteries.

The first title compound, [Au(C7H11BrN2)2]I, crystallizes in the space group P\overline{1} without imposed symmetry. The cations and anions are linked to form chains by Br...I...Br halogen-bond linkages. The second title compound, [Au(C7H11BrN2)2][AuI2(C7H11BrN2)2]I2, is an adduct of the first and its formally I2-oxidized AuIII analogue. It also crystallizes in space group P\overline{1}, whereby both gold atoms occupy inversion centres. The extended structure is a reticular layer involving Br...I...Br and I...I...Au linkages.

A family of: 1:1 cocrystals 11-Aza:4-X-SalA have been prepared from the potent anti-malarial compound 11-azaartemisinin with 4-halosalicylic acids. When X = 4-Cl, 4-Br and 4-I, two conformational polymorphs can be isolated in each case. Monoclinic type-I was found previously for parent 11-Aza:SalA (1) and 11-Aza:4-Br-SalA (3a) which have polar 21 stacks of molecular pairs with no short halogen bond contacts between stacks. Orthorhombic type-II is found for 4-Cl (3b) and 4-I (4b) from solution growth. This has a translational stack of molecular pairs involving a conformational change of the acid-lactam hetero-synthon and supramolecular association of stacks via halogen bonds. Notably, phase pure polymorph type-I can be formed for 4-Cl (3a) and 4-I (4a) by hetero-seeding with 11-Aza:SalA, whist conversely phase pure type-II for 4-Br (2b) can be formed using homo-seeding from liquid assisted grinding (LAG) product. This work demonstrates both the viability of engineering polymorphic cocrystal forms using hetero-seeds and the involvement of halogen bonds in helping to discriminate quite different polymorphic types. [ABSTRACT FROM AUTHOR]

Spontaneous resolution leading to conglomerate crystals remains a significant challenge. Here we propose the formation of orthogonal homochiral supramolecular helices in at least two dimensions to allow spontaneous resolution. We suggest the design rationale that the chiral species is made into helical building blocks to allow the helix formation. As a proof‐of‐concept, acetylalanine was made into a helical short azapeptide, its N‐amidothiourea derivative containing a β‐turn structure, to which a halogen atom was further introduced at the phenylthiourea aromatic ring. The resultant folded species undergoes both intermolecular hydrogen and halogen bonding across the turn structure to form orthogonal intermolecular hydrogen‐bonded and halogen‐bonded supramolecular helices in two dimensions, and undergoes chiral resolution upon crystallization. Meanwhile, counterparts containing either an F‐substituent with weak halogen bonding or no halogen atom crystallize as racemic compounds. [ABSTRACT FROM AUTHOR]

• First synthesis of poly-fluorinated palladium complex reveals rare non-covalent interactions. • Novel type II C − F⋯F − C halogen bonds discovered in a new fluorinated complex. • Unique C − H⋯F and C − H⋯Cl(−Pd) blue-shifting hydrogen bonds were observed. • NoTable 90° dihedral angle found in 2-(8FH-py)2PdCl2 complex, highlighting hydrophobic interactions. • QTAIM, NCI, and hirshfeld analyses confirm rare C − F⋯F − C and C − H⋯X non-covalent interactions. The sp3 -based C−F⋯F − C halogen bonds (XBs) and blue-shifting C−H⋯X (X = F , Cl) hydrogen bonds (HBs) are a relatively unusual phenomenon in chemistry, due to their uncommonness and the challenges associated with their direct observations. To investigate these interactions, a novel fluorinated trans-[2-(HCF 2 (CF 2) 3 CH 2 OCH 2) 2 -py-PdCl 2 ], abbreviated as 2-(8FH-py) 2 PdCl 2 complex, has been synthesized and structurally characterized. The incorporation of a fluorinated ponytail on the pyridyl ring in the 2-(8FH-py) 2 PdCl 2 complex allows us to explore rare sp3-based type II C9−F4⋯F6−C10 and C8−F2⋯F6−C10 XBs dimers. These findings suggest, for the first time, the formation of halogen bonding dimers through C−F⋯F−C interactions, to our knowledge. Additionally, the 2-(8FH-py) 2 PdCl 2 reveals interesting blue-shifting C−H⋯X hydrogen bonding interactions in the crystal packing. These C−H⋯F interactions connect adjacent molecules in a head-to-tail manner, resulting in the continuation of R 2 2(9) synthons along the crystallographic a-axis. These hydrophobic interactions, which are expected to be very different from the typical hydrophilic interactions, play a crucial role in enhancing the self-assembly and stability of the crystal structure. In addition, the presence of blue-shifting C−H⋯X hydrogen bonding interactions affirmed by the FT-IR studies. Furthermore, the high positive values of electron density (ρ) and Laplacian density (∇2 ρ) from quantum theory of atoms in molecule (QTAIM) analyses suggest the presence of electrostatic and weak interactions between atoms. We believe that this discovery will open up new opportunities for exploring and utilizing fluorinated complexes in various scientific fields, fluoro-pharmaceuticals and crystal engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cl−-water halogen bonds enable the Zn2+ structural diffusion. • Halogen bonds reduce the Zn2+ de-solvation energy barrier. • Accelerated ions diffusion enhance the Zn anode reversibility. Despite their low cost and intrinsic safety, aqueous rechargeable zinc-ion batteries suffer from rapid performance deterioration originating from parasitic reactions and inhomogeneous deposition on the Zn anode. Halogen bonds share similarities with hydrogen bonds, yet their unique directionality, strength tunability, and hydrophobicity provide a promising approach for enhancing the reversibility of Zn anodes. Herein, a systematic comparison of ionic liquids with different anions, acetate (Ac−) and chloride (Cl−), is performed to explore the non-covalent interactions in regulating ion solvation and dynamic behaviors of electrolytes. Different from the Ac− possessing a strong capacity to form hydrogen bonds with water, the Cl−-water halogen bonds not only enable the structural diffusion of Zn2+ with better diffusion efficiency but also reduce the Zn2+ de-solvation energy barrier to promote uniform Zn nucleation. Consequently, the accelerated ions diffusion and homogeneous Zn deposition work in synergy to ensure high reversibility of Zn anode. These fundamental insights highlight the importance of hydrogen and halogen bonds in determining the dynamics and electrochemical behavior of electrolytes, providing theoretical guidance for the rational design of high-performance electrolytes. [ABSTRACT FROM AUTHOR]

In this study, we investigated how the presence of multiple intermolecular interaction sites influences the heteromeric supramolecular assembly of N-[(3-pyridinylamino) thioxomethyl] carbamates with fluoroiodobenzenes. Three targets—R-N-[(3-pyridinylamino) thioxomethyl] carbamate (R = methyl, ethyl, and isobutyl)—were selected and crystallized, resulting in three parent structures, five co-crystals, and one co-crystal solvate. Three hydrogen-bonded parent crystal structures were stabilized by N-H···N hydrogen bonding and assembled into layers that stacked on top of one another. Molecular electrostatic potential surfaces were employed to rank binding sites (Npyr > C=S > C=O) in order to predict the dominant interactions. The N-H⋯H hydrogen bond was replaced by I⋯Npyr in 3/6 cases, I⋯C=S in 4/6 cases, and I⋯O=C in 1 case. Interestingly, the I⋯C=S halogen bond coexisted twice with I⋯Npyr and I⋯O=C. Overall, the MEPs were fairly reliable for predicting co-crystallization outcomes; however, it is crucial to also consider factors such as molecular flexibility. Finally, halogen-bond donors are capable of competing for acceptor sites, even in the presence of strong hydrogen-bond donors. [ABSTRACT FROM AUTHOR]

Hydrohalides of Lewis bases may act as halogen bond (XB) acceptors and combine two directional interactions, namely, hydrogen bonds (HB) and XBs in the same solid. 3‐(1,3,5‐Trimethyl‐1H‐pyrazol‐4‐yl)acetylacetone (C11H16N2O2, HacacMePz) was protonated with HX (X = Cl or Br) to afford the hydrohalides, C11H17N2O2+·X− or H2acacMePz+·X− (1, X = Cl; 2, X = Br). Hydrohalides 1 and 2 are isomorphous and adopt a classical dipole packing. Consistent with the observation for most β‐diketones, the enol form with an intramolecular HB is observed. Additional noteworthy interactions are HBs of the protonated pyrazolium towards the X− anion at donor–acceptor distances of 2.9671 (17) Å for 1 and 3.159 (4) Å for 2. Cocrystallization of hydrobromide 2 with the XB donor tetrafluorodiiodobenzene (TFDIB) leads to the adduct C11H17N2O2+·Br−·0.5C6F4I2·H2O or (H2acacMePz+·Br−)2·(H2O)2·TFDIB (3), in which the XB donor TFDIB is situated on a crystallographic centre of inversion. Classical HBs link organic cations, water molecules and Br− anions into chains along [010]. Almost orthogonal to this interaction, XBs with Br...I = 3.2956 (4) Å connect neighbouring chains along [102] into two‐dimensional sheets in the (10) plane. Assisted by their negative charge, halide anions represent particularly good nucleophiles towards XB donors. [ABSTRACT FROM AUTHOR]

A new interhalogen ionic liquid [C17H25N3Br]+[IBr2]− (IL-1) was synthesized from its triazolium iodide precursor [C17H26N3+I−] in THF under cold and basic conditions. X-ray diffraction data showed that IL-1 is composed of two moieties contained in a triclinic unit cell; the five-membered triazolium cation and an almost linear iodidobromide anion, IBr2−. The Br atoms of the anion form quadfurcated C–H···Br hydrogen bonds with neighbouring cationic halo-1,2,3-triazolium H-species. Intermolecular Br···Br halogen bonds and I···πtriazole interactions form a distinctive ring-like pattern that links together four molecular units in the crystal packing. Hirshfeld surface analysis revealed that the most significant dnorm surface contribution at 59% is due to H···H and reciprocal C···H contacts, while the Br···Br contacts only contributed 3%. The prevalence of extensive H···H and C···H contacts is potentially due to the linear aliphatic chain, the N-octyl wingtip substituent of the triazolyl moiety. The Hirshfeld surface mapping also shows the contribution of intermolecular C–H···Br interactions at 26% of all contacts. The title compound (IL-1) showed interesting photophysical properties in MeCN solution, with an absorption band at 254 nm and two-shoulder emission bands due to strong π → π∗ transitions from the triazolium moiety, indicating the presence of two energetically associated species. Structural and photophysical studies on a new ionic liquid compound containing a mixed halide anion [C17H25N3Br]+[IBr2]− have yielded important results on intermolecular interactions between the triazolium cation and the iodidobromide counterion. [ABSTRACT FROM AUTHOR]

Although the non-covalent interactions such as hydrogen bonds and Van der Waals bonds are considered as weak but have a significant impact on the characteristics of the molecule in solution and the crystalline phase. The nature and strength of such intermolecular interactions result in various physicochemical and biological properties in crystal structures. In the present study, a quantitative analysis of intermolecular interaction in the crystal packing of some bromine substituted coumarin derivatives has been undertaken for lattice energy and intermolecular interaction energies analyses using a computational approach. The analysis shows that the energy contribution of halogen bonds such as C-Br...O and C-Br...π is quite significant in the crystal structures of bromine substituted coumarins. Besides, the C-H...O, C-H...Br and π...π interactions are also found to have a profound effect on the molecular packing of these structures. Molecular interactions with reference to the packing mechanism in each molecule are studied in detail. It is expected that empirical analysis of molecular energy interactions will help in understanding the role of various structural motifs in crystal packing. [ABSTRACT FROM AUTHOR]

The halogen bond has been widely used as an important supramolecular tool in various research areas. However, there are relatively few studies on halogen bonding related to molecular chirality. 3-(2-Halophenyl)quinazoline-4-thione derivatives have stable atropisomeric structures due to the rotational restriction around an N-C single bond. In X-ray single crystal structures of the racemic and optically pure N-C axially chiral quinazoline-4-thiones, we found that different types of intermolecular halogen bonds (C=S⋯X) are formed. That is, in the racemic crystals, the intermolecular halogen bond between the ortho-halogen atom and sulfur atom was found to be oriented in a periplanar conformation toward the thiocarbonyl plane, leading to a syndiotactic zig-zag array. On the other hand, the halogen bond in the enantiomerically pure crystals was oriented orthogonally toward the thiocarbonyl plane, resulting in the formation of a homochiral dimer. These results indicate that the corresponding racemic and optically pure forms in chiral molecules are expected to display different halogen bonding properties, respectively, and should be separately studied as different chemical entities. [ABSTRACT FROM AUTHOR]

The study of two complexes of fluorenonophane with CHCl3 and CHBr3 molecules has revealed that they differ mainly by the halogen bonds between host and guest molecules. The experimental and theoretical quantum chemical study has shown that the strength of a halogen bond depends on the nature of a halogen atom as well as its orientation to the π-system. The more positive electrostatic potential was revealed at the bromine atom indicating the stronger halogen bond with its participation that was confirmed by the interaction energies calculated for corresponding dimers and the evaluation of the true energy of a halogen bond. The orientation of the chlorine atom at the carbon aromatic atom instead of the center of the benzene ring leads to the shortest Hal...C distance that points out the stronger interaction according to the geometrical characteristics. The EDA analysis of the fluorenonophane complexes with CHCl3 and CHBr3 and their analogs with one halogen atom replaced by the hydrogen atom allows us to presume that the nature of halogen bonding is rather dispersive than electrostatic. [ABSTRACT FROM AUTHOR]

The molecular and crystal structures of the title compound, C4H4Cl2N2O3, were investigated by single-crystal X-ray diffraction and a Hirshfeld surface analysis. The title compound was synthesized by a new type of reaction using Mg(ReO4)2 as a new catalyst and a possible mechanism for this reaction is proposed. The six-membered ring adopts a half-chair conformation. In the crystal, hydrogen bonds connect the molecules into double layers, which are connected to each other by halogen bonds. The Hirshfeld surface analysis revealed that the most important contributions for the crystal packing are from O...H/H...O (35.8%), Cl...Cl (19.6%), Cl...H/H...Cl (17.0%), H...H (8.3%), C...O/O...C (4.3%), Cl...O/O...Cl (4.2%) and O...O (4.1%) contacts.

Summary: Halogen···halogen (X···X) short contacts, especially halogen bonds (XBs), have been widely used in multifarious fields because of their bridging function among luminophores, as well as their well-known heavy atom effect. Little attention, however, has been paid to the luminescent ability of halogen clusters. It remains unknown whether they could be emissive. Herein, to our knowledge, we report the first examples of emissive halogen clusters with fluorescence-phosphorescence dual emission in an aggregated state and even under ambient conditions, which should be attributed to the extended delocalization through effective intra- and intermolecular X···X contacts. Additionally, multi-tunable luminescence in response to excitation wavelength, temperature, and compression is noticed. These results unveil the potential of halogen clusters as novel chromophores and may inspire further exploration of nonconventional luminophores involving halogen moieties.

Rapid capture of 129I with high volatility and toxicity in the environment has attracted much attention. Herein we reported a firstly synthesized nonporous material: pyridine N‐oxides (NTPO and ATPO) as iodine adsorbent. Both of NTPO and ATPO exhibit remarkable performance on the adsorption of iodine in aqueous solution, vapor state and organic solvents. Upon the capture of iodine, pyridine N‐oxides were transformed to binary cocrystals combined with the pyridine N‐oxides and iodine which is driven by halogen bond between iodine and oxygen atoms. Moreover, pyridine N‐oxides shows high chemical, thermal and moisture stability. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are considered to be the most promising next‐generation photovoltaic technology. Among all the configurations of PSCs, the printable hole‐conductor‐free mesoscopic PSC (p‐MPSC) has unique advantages on low cost, large‐area fabrication and fabulous stability, which endows it with the greatest potential for industrialization. The interfacial recombination losses, especially at the perovskite/carbon interface, are the bottleneck for further improving the power conversion efficiency (PCE) of p‐MPSCs. 2‐Bromo‐6‐fluoronaphthalene is introduced as an interfacial modulator for p‐MPSCs through post‐treatment. The bromo‐terminal acts as an electrophilic site to interact with the iodine ion in perovskite via the noncovalent halogen bond. Meanwhile, the fused ring of naphthalene is capable to accommodate electron density that is attracted from the perovskite. This interaction induces a more favorable band structure at the interface. The hole extraction is promoted and the interfacial nonradiative recombination is inhibited. Accordingly, a champion p‐MPSC with an improved PCE of 16.77% from 15.50% of the pristine device is obtained. [ABSTRACT FROM AUTHOR]

The synthesis of iodine(I) complexes with either benzoimidazole or carbazole‐derived sp2N‐containing Lewis bases is described, as well as their corresponding silver(I) complexes. The addition of elemental iodine to the linear two‐coordinate Ag(I) complexes produces iodine(I) complexes with a three‐center four‐electron (3c–4e) [N−I−N]+ bond. The 1H and 1H‐15N HMBC NMR studies unambiguously confirm the formation of the complexes in all cases via the [N−Ag−N]+→[N−I−N]+ cation exchange, with the 15N NMR chemical shift change between 94 to 111 ppm when compared to the free ligand. The single crystal X‐ray crystallographic studies on eight I+ complexes revealed highly symmetrical [N−I−N]+ bonds with I−N bond distances of 2.21–2.26 Å and N−I−N angles of 177–180°, whilst some of the corresponding Ag+ complexes showed a clear deviation from linearity with N−Ag−N angles of ca. 150° and Ag−N bond distances of 2.09–2.18 Å. [ABSTRACT FROM AUTHOR]

The first title compound, [Au(C7H11BrN2)2]I, crystallizes in the space group P... without imposed symmetry. The cations and anions are linked to form chains by BrIBr halogen-bond linkages. The second title compound, [Au(C7H11BrN2)2][AuI2(C7H11BrN2)2]I2, is an adduct of the first and its formally I2-oxidized AuIII analogue. It also crystallizes in space group P..., whereby both gold atoms occupy inversion centres. The extended structure is a reticular layer involving Br···I···Br and I···I···Au linkages. [ABSTRACT FROM AUTHOR]

Supramer analysis was applied to explain the earlier discovered phenomenon of the transformation of nonselective glycosylation into stereospecific one upon changing the glycosyl donor concentration. The supramer analysis is a part of the supramer approach being developed by us and makes it possible to find concentration ranges separated by "critical" concentrations at which supramolecular aggregates (supramers) have different structures. As a result, the "critical" concentration for solutions of 2,3,5-tri-O-benzoyl-α-d-arabinofuranosyl bromide (1) in acetonitrile was found by polarimetry, and that for solutions of glycosyl bromide 1 in 1,2-dichloroethane (DCE) was found using static light scattering. The presence of nanosized supramers in solutions of 1 in acetonitrile and nano- and mesoscale supramers in solutions of 1 in DCE was demonstrated using dynamic light scattering. An analysis of the obtained experimental and earlier published data suggested a possibility of both formation of halogen bonds involving DCE molecules and halogen bond-mediated supramolecular aggregation of molecules of the dissolved substance in this solvent. [ABSTRACT FROM AUTHOR]

Simulation results obtained for isostructural dihalogenide, hexahalogenbenzene, and halogenotrinitromethane crystals under external hydrostatic compression are analyzed. Along with macroscopic mechanical properties such as anisotropy of uniaxial and hydrostatic compressibility of crystals and orientation of the axes of maximal and minimal uniaxial and hydrostatic compressibility, we consider also microscopic properties such as electronic characteristics of halogen bonds and non-covalent interactions which are estimated using quantum electron pressure and its scalar indicator. It is established that halogen bonds are more sensitive to external compression than typical Van der Waals interactions of halogens. [ABSTRACT FROM AUTHOR]

Short supramolecular Br···Br and I···I contacts in chalcogenides Ti4Se9I6, V4S9Br4, Ta4S9Br8, and Ta4Se9I8 with a square {M4Q9} core are theoretically studied by quantum chemical calculations within the density functional theory (ωB97XD/DZP-DKH) and the QTAIM topological analysis of the electron density distribution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cocrystals based on I-, Br-based halogen-bond donors and N-based halogen-bond acceptor were constructed. • Strength and density of σ-hole could affect degree of electron-hole separation and charge carrier transport. • Tuning photoelectric response of halogen-bonded cocrystals can be achieved employing the σ-hole effect. • Halogen-bonded cocrystals are enable to effectively photocatalytic reduce U(VI) of uranium contamination. The mechanism of how the internal composition of halogen-bonded cocrystals affecting photoelectric properties is ambiguous. Herein, we report a series of stable halogen-bonded cocrystals containing I-, Br-based halogen bond donors and N-based halogen bond acceptor. The halogen bonds served an intrinsic hub, and the two parts (donor and acceptor) were spliced into a highly ordered periodic network with a tight electronic configuration. The charge transfer within lattice induced by the σ-hole effect activates disparate photoelectric phenomena. The results uncover that the degree of photoelectric response of cocrystals can be adjusted rationally by manipulating the intensity and density of σ-holes with an atomic precision at the molecular level. The experimental and theoretical studies of the σ-hole effect pave the way to simplify the design principle of functional cocrystals. Eventually, benefiting from the fascinating photoelectric activity, halogen-bonded cocrystals exhibited excellent photocatalytic reduction ability of radionuclide uranium. [ABSTRACT FROM AUTHOR]

The title compound, C8H4Br2O4·C2H6O2, crystallizes with one-half of a 2,5-dibromoterephthalic acid (H2Br2tp) molecule and one-half of an ethylene glycol (EG) molecule in the the asymmetric unit. The whole molecules are generated by application of inversion symmetry. The H2Br2tp molecule is not planar, with the dibromobenzene ring system inclined by a dihedral angle of 18.62 (3)° to the carboxylic group. In the crystal, the H2Br2tp and EG molecules are linked into sheets propagating parallel to (\overline{1}01) through O—H...O hydrogen bonds, thereby forming R44 (12) and R44 (28) graph-set motifs. Br...O and weak π–π stacking interactions are also observed. Hirshfeld surface analysis was used to confirm the existence of these interactions.