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Wiązanie trielowe, tetrelowe, pnikogenowe, chalkogenowe, halogenowe, aerogenowe : oddziaływania niekowalencyjne pierwiastków bloku P

Zierkiewicz Wiktor, Michalczyk Mariusz

Wiadomości Chemiczne

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2020

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[Z] 74, 9-10

587--607

EN

It is widely accepted that hydrogen bonds contribute into a variety of meaningful processes in nature and human body which has reflection in the share of the scientific community attention over the last decades. Recent years have seen a veritable explosion of research into noncovalent interactions that are analogous to the commonly acknowledged H-bonds. It became obvious that detailed investigation of these types of short contacts should be extensively considered as the main target for theoretical chemistry. In 2007 the article described the σ-hole concept enlightened the phenomena of the halogen bond. Later extensions of this concept into the other elements in periodic table provided the necessary knowledge about the origin of these interactions and gave arise for introducing the other members of the σ-hole bonds family as the chalcogen, pnicogen, tetrel and triel bonds or even those involving noble gases. The foundation of the σ-hole theory is the presence of the region of thinned electronic density caused by the anisotropic accumulation of the negative charge on the covalent R-X bond (where X=halogen) what causes the rising of positive electrostatic potential on the outer side of X atom. This particular location becomes the binding site for the approaching nucleophile. As the σ-hole is located in plane of molecule on an extension of covalent bond, some molecules also contain a σ-hole region situated above and below the plane of the molecular framework. In current work the representative examples of complexes bonded through the σ- or π-holes and their most important features have been briefly given. The main goal was to show the diversity of this type of interaction which covers nearly all the elements of the block p of periodic table. Triel bonds are produced mainly by -hole interaction with Lewis bases and can be characterized by different nature for different elements (boron complexes are stabilized by electrostatics and charge transfer, while Al and Ga ones mostly by electrostatics). In tetrel, pnicogen and chalcogen bonded complexes it has been shown that during the process of dimerization the substantial geometric distortion is observed on the π-hole donor molecules. It causes the creation of the second complexation path through newly created π-hole. In chalcogen bonded complexes the alternative dimer is stabilized by π-hole and something like - due to presence of lone electron pair of chalcogen. Within the halogen bonds one can highlight the issue of weakening the negative hyperconjugation on the molecules of methylated derivatives of ammonia (like methylamine). It is caused by the appearing of σ-hole donor (FCCl3) which takes control of the majority part of intramolecular charge transfer and in this way enhances the link between subunits at the price of hampering the internal conjugation. Finally, the short report of aerogen bonds in literature is inserted in the last chapter of current paper. Some molecules with noble gases connected with highly electron-withdrawing constituents are able to generate both: σ- and π-hole on their surfaces and in consequences the stable complexes with Lewis bases (for example, diazines). The presence of the latter proves that the discussed types of interaction are very common for massive amount of atoms, even for those which are considered as less reactive.

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Efekt kooperatywności oddziaływań niekowalencyjnych w wybranych układach molekularnych stabilizowanych wiązaniami wodorowymi i halogenowymi

Domagała Małgorzata, Dominikowska Justyna, Palusiak Marcin

Wiadomości Chemiczne

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2019

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[Z] 73, 1-2

33--52

EN

Among various so-called weak interactions, a halogen bond [8 and references therein] is currently probably one of more explored by researchers. This is due to the fact that it has several properties in common with the hydrogen bonding, and thus, similarly as already well characterised H-bond, it may have a crucial role in different physical, chemical, and biological processes. This bond is formed due to stabilising interactions between a region of positive charge located on a surface of the halogen atom and the other atomic center possessing the electron charge surplus (e.g. a lone pair) [8]. The region of positive charge appears on the halogen atom surface due to deformation of its electron cloud resulting in its ellipsoidal shape with the short axis opposite the covalent bond and the long axis in the perpendicular direction [11]. This results in a particular distribution of local charges on the atomic surface, as shown in Figure 1. As a consequence the halogen atom may exhibit a dual character, acting as either electron charge donor or acceptor, depending on the type of interaction and the direction of the appearing interactomic contact. A good example of such situation is shown in Figure 2. Thus, one may consider the situation when two interactions are formed simultaneously and the halogen atom acts as an electron charge donor and acceptor at the same time. For such situation the synergism of both interactions may strengthen complexation. In order to analyze that case, various representative complexes were investigated [13, 17, 18, 20, 21] by means of many-body interaction approach [5, 6]. In general, it appears that as distinct to hydrogen bond [2–4], the synergism is rather weak, with some exceptions for iodine atom due to stronger halogen bonds formed by that atomic centre [13, 17, 18]. In the case of halo-amine tetramers [21] the additional stabilising effect derived from back bonding of π type was found – for the first time for a halogen bond.

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Propedeutyka kierunkowych oddziaływań miedzycząsteczkowych. Wiązania wodorowe, oddziaływania asocjacji warstwowej i wiązania halogenowe

Kruszyński R.

Zeszyty Naukowe. Chemia / Politechnika Łódzka

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2011

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Z. 50

5-47

EN

The review presents the typical bonding intermolecular interactions: hydrogen bonds, halogen bonds and stacking interactions. The first part describes the specific types of intermolecular interactions, including their definitions, energy and selected properties. The second part deals with the application of quantum-mechanical methods to study of intermolecular interactions, especially the appliance of the natural bond orbitals method, and usage of ab intio calculations for solving of structural problems appearing during the above mentioned studies. All above referred interactions have been presented in orbital terms. The third part describes the novel employment of graph theory to characterise the motifs formed by intermolecular interactions in the solid state.

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Wiązanie wodorowe i inne oddziaływania typu kwas Lewisa-zasada Lewisa

Grabowski S. J.

Wiadomości Chemiczne

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2011

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[Z] 65, 11-12

975-1001

EN

Hydrogen bond is analyzed very often since its importance in numerous chemical, physical and biological processes is very well known. It covers the broad range of various interactions; sometimes this is the subject of discussions and polemics if some of them may be classified as hydrogen bonds. This is because there are numerous definitions of hydrogen bond interaction, often they are hardly accepted since they are not univocal. For example one can mention different types of the proton acceptors for hydrogen bonds; one center electronegative atoms, multi-center acceptors such as đ-electrons or even ó-electrons. There are the other interactions which play the key role in various processes and phenomena. All are often named as no-covalent interactions but the other term, Lewis acid–Lewis base interactions seems to be more accurate. One can mention halogen bond, hydride bond or dihydrogen bond. These interactions may be treated as counterparts or competitors of hydrogen bond. The common characteristic for them, including hydrogen bond, is the electron charge transfer from the Lewis base to the Lewis acid. It was found that the amount of this transfer corresponds roughly to the strength of the interaction. In recent years the ó-hole concept was introduced and developed and it was applied to the Lewis base–Lewis acid interactions. According to this concept the atomic centers are characterized by the presence of the regions of positive and negative electrostatic potentials; very often both regions are detected even for atoms which are commonly known as electronegative ones. In such a way halogen atoms, especially if connected by covalent bond with carbon, may act as Lewis acids and also as Lewis bases. In the first case the halogen bond is formed, recently extensively studied. In this review the characteristics of different Lewis base–Lewis acid interactions are given as well as their common features are presented.