Boron-nitrogen Compounds Research Articles

Boron-Nitrogen Compounds in Luminescent Materials: A Review of Applications and Synthesis Methods

Boron-nitrogen compounds (B-N) have emerged as a promising material due to their unique electronic structure and excellent luminescent properties, showing great potential in organic light-emitting diodes (OLED) and electroluminescent devices. This paper systematically reviews the molecular structure, optical, and electronic properties of B-N compounds, discusses their applications in luminescent materials, and explores synthesis methods, including Friedel-Crafts-type reactions, borohydride reduction reactions, and olefin metathesis. Additionally, the paper analyzes key factors in controlling the performance of luminescent materials, investigating the impact of synthesis conditions, doping, and the preparation of composite materials on luminescent efficiency and stability. Despite significant progress in B-N compound research, challenges remain in synthesis precision, luminescent efficiency, and industrial production. Future research should focus on improving targeted synthesis capabilities, optimizing electronic structure and luminescent performance, and exploring more efficient, cost-effective production processes. With continued innovation, B-N compounds are poised to become a foundation for the next generation of high-efficiency luminescent materials, driving advancements in optoelectronic technology.

BORON-NITROGEN COMPOUNDS IN THE REACTION OF BORIC AND BORONIC ACIDS WITH AMINES

The article is a review of boric or arylboronic acids reactions with aliphatic and aromatic amines. The review is for informational purposes only on the interaction of the acids in question with amines. It is shown that the data on the boric acid reaction with amines are contradictory and, at present, there is no confirmed information on obtaining a covalent bond between boron and nitrogen without the involvement of hydroxyl groups and the cyclic systems formation, for example, in the oxazaborolidines case. Literary searches have shown that the report on the anilinboronic acid production in 1963 was not developed, and there is also no data on the synthesis of those compounds. Along with this, boric acid easily forms borate salts of various configurations with amines, that is confirmed by modern methods of analysis (IR- and NMR-spectroscopy, elemental analysis). It has also been shown that boric acid is capable of forming compounds with an intramolecular donor-acceptor bond between boron and nitrogen. The theoretical calculations results and experimental data on the arylboronic acids interaction, with various aromatic ring substituents, with pyrocatechines, o-phenylenediamines, 2-hydroxybenzenetiols and o-benzenedithiols are presented. It is noted that competitive formation of anhydride-like structures is observed in all these reactions. It is shown that the interaction with pyrocatechins is the most thermodynamically advantageous. In the arylboronic acids reaction with ortho-benzenedithiols, ortho-hydroxybenzenetiols in chloroform, the corresponding oxathiaboroles and dithiaboroles were not isolated. The latter were obtained by the boron trichloride reaction with the corresponding electron donors. It is reported that there is no information on the preparation of condensation products of phenylboronic acids with aniline and benzylamine. For citation: Strokova S.V., Lenskiy M.A. Boron-nitrogen compounds in the reaction of boric and boronic acids with amines. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 6-13. DOI: 10.6060/ivkkt.20246706.6988.

Reversible hydrogen storage and release mechanism of a B2N monolayer: a first-principles insight.

It was found the physical adsorption could be an efficient strategy for high capacity, high efficiency and high safety in hydrogen storage. In this research, a systematic investigation into the potential of the B2N monolayer as an excellent physical adsorption hydrogen storage material is conducted by utilizing the first-principles calculation method. The findings of the investigation demonstrate that the B2N monolayer has a planar lattice and excellent structural stability. It is possible for H2 molecules to adsorb onto the B2N monolayer spontaneously. Both the individual adsorption and saturation adsorption corresponded to average adsorption energies ranging from -0.221 to -0.194 eV, fulfilling the physical adsorption criteria. In the case of saturation adsorption, a 1 × 2 × 1 B2N supercell can store a total of 24 H2 molecules, with the hydrogen gravimetric density up to 14.511 wt% and volumetric density up to 138 g L-1. A semi-empirical calculation method is used to research the performance of the system in terms of adsorption and desorption with actual temperature and pressure conditions. Under the actual conditions with adsorption carried out at 30 atm/233 K and desorption carried out at 3 atm/358 K, the maximal reversible hydrogen storage capacity of the hydrogen storage system based on the B2N monolayer can still reach 12.157 wt%, which is superior to that of many other boron-nitrogen compounds and metal-free functionalized hydrogen storage materials. The findings of this work indicate that the pristine B2N monolayer is one of the promising physical adsorption materials which could achieve excellent reversible hydrogen storage under defined conditions.

THERMAL DECOMPOSITION OF MONO- AND DIETHANOLAMINEBORATE MODIFIED WOOD IN AIR ATMOSPHERE

"For cellulosic materials used in various branches of the economy, the issue of increasing thermal stability is still relevant today. Especially acute is the problem of fire resistance for wood materials used in building structures. In our work, we investigated the effect of mono- and diethanolamine borates on the thermal decomposition of wood in an air atmosphere. It has been previously found that mono- and diethanolaminoborates, when used as surface modifiers, provide 100% biostability to plant raw materials. In this regard, the purpose of the study was to identify the flame retardant effect of the described modifiers. In the course of the study, it was found that the developed compositions, the main components of which are boron-nitrogen compounds, effectively reduce the combustibility of wood materials, suppress smoldering, and reduce the burning rate of wood. Since it is the smoldering of wood after the liquidation of the fire that is the main cause of structural collapse, which prevents evacuation during the fire, the use of the developed compositions for fire protection of wooden structures is extremely appropriate. A regression model of the dependence of activation energy on conversion has been obtained and substantiated on the basis of correlation and regression analysis. The presented semi-logarithmic model can be further applied to predict the dependence of the activation energy value of the thermal decomposition process of modified wood on the degree of conversion."

Pyrolysis of Pine Wood in the Presence of Boron-Nitrogen Compounds.

The actuality of this research is determined by the intensification of new ways of processing woody biomass. This requires revealing the impact of various physicochemical factors on the thermal degradation of wood biopolymers. Boron-nitrogen surface modifiers are used for wood antisepsis and we decided to check their effect on flammability. The aim of the research was to evaluate the flame retardant effect of boron-nitrogen surface modifiers of wood in an inert atmosphere (nitrogen was used). The evaluation was carried out by thermal analysis of modified and the control pine wood samples. The thermal analysis included thermogravimetry, differential scanning calorimetry and kinetic parameters of thermal degradation. It was found that the flame retardant effect of boron-nitrogen wood surface modifiers was not significantly pronounced in the nitrogen atmosphere. The mechanism of the flame retardant effect of boron-nitrogen compounds is reduced to "shielding" of the surface and increasing the proportion of carbonized residue. On the basis of correlation-regression analysis of kinetic parameters of wood thermodestruction in a nitrogen atmosphere, mathematical models of activation energy dependence on conversion were obtained and substantiated. The developed models can be further applied to calculate the predicted value of wood activation energy in the nitrogen atmosphere at any conversion value.

Modification of Cellulosic Materials with Boron-Nitrogen Compounds

Wood fiber and its products are modified to increase fire and bio-resistance. The best results are achieved by using modifiers that enter into chemical interaction with the hydroxylated substrate, forming the organic matrix of the materials. The purpose of the research described in the article was to study the possibility of using boron-nitrogen compounds to modify cellulose and cellulose-containing materials to improve the performance, bio- and fire-protective properties of construction materials, as well as to optimize the consumption of boron-nitrogen compounds. As a result of the research, it was found that the boron-nitrogen compounds used in the compositions developed here chemically interact with hydroxyl groups at the C6-atom of cellulose. The chemical interaction of boron-nitrogen compounds with cellulose is an inter-crystalline process occurring without destruction of the crystal structure of the substrate since the modifier molecules bind with the more accessible hydroxyl groups of the amorphous regions of cellulose. Thus, surface modification with boron-nitrogen compounds does not result in accelerated aging of cellulose-containing materials and loss of strength but, on the contrary, increases the durability of wooden structures.

Computational evaluation of lithium functionalized Penta-BN2 as promising reversible hydrogen storage

Finding advanced hydrogen storage materials with high capacity and high efficiency is a key issue for hydrogen transportation and application. In this study, the first-principles calculation method is used to examine the potential of 2D pentagonal BN2 (Penta-BN2) as an excellent hydrogen storage material. The results indicate that Penta-BN2 has superior metallic and structural stable properties. The pristine Penta-BN2 is found to have weak adsorption energy for H2 molecules, which cannot meet the requirements of hydrogen storage. However, the Li-functionalized Penta-BN2 substrate is found to be relatively excellent to adsorb H2 molecules. A Li atom is bound closely to Penta-BN2 with large adsorption energy reaching more than 3.79 eV, and the 2 × 2 × 1 Penta-BN2 supercell can be suitably accommodated 4 Li atoms. 4Li-functionalized Penta-BN2 stores up to 16H2 molecules with a hydrogen gravimetric density of 8.70 wt%. The adsorption and desorption capacity of the system for H2 molecules under practical temperature and pressure conditions are investigated with semi-empirical calculations. The maximum reversible hydrogen storage capacity is up to 7.92 wt% between the practical condition of 30 atm/233 K for adsorption to 3 atm/358 K for desorption, which is better than other 2D pentagonal materials and boron-nitrogen compounds. The proposed investigations of this work illustrate that Li-functionalized Penta-BN2 is a promising hydrogen storage material with high efficiency, reversibility, and high-capacity characteristics.

Cyclic Six-Atomic Boron-Nitrides: Quantum-Chemical Consideration by Ab Initio CCSD(T) Method

By means of the CCSD(T)/6-311++G(df,p) and G4 quantum-chemical calculation methods, the calculation of the molecular and electronic structures of boron–nitrogen compounds having the B3N3 composition was carried out and its results were discussed. It was noted that seven isomeric forms with different space structures can exist; wherein, the most stable form is a distorted flat hexagon with alternating B and N atoms, with both B and N atoms forming regular triangles, but with different side lengths. The values of geometric parameters of molecular structures in each of these compounds are presented. Also, the key thermodynamic parameters of formation (enthalpy ΔfH0, entropy S0, Gibbs’ energy ΔfG0) and relative total energies of these compounds are calculated.

ОПРЕДЕЛЕНИЕ КИНЕТИЧЕСКИХ ПАРАМЕТРОВ ТЕРМОДЕСТРУКЦИИ И ГРУППЫ ОГНЕЗАЩИТНОЙ ЭФФЕКТИВНОСТИ ДРЕВЕСИНЫ СОСНЫ, МОДИФИЦИРОВАННОЙ БОРАЗОТНЫМ АНТИПИРЕНОМ

Wood is a combustible material. To reduce combustibility, wood is modified with functional compounds of phosphorus, boron and nitrogen, inoculation of which changes the chemical composition of the surface layer of wood and its structure. The mechanism of action of flame retardants is related to their influence on the energy and entropy characteristics of the thermodestruction process. Considering that boron nitrogen compounds are effective flame retardants and react with wood components under “mild” conditions, the effect of grafting of a borax modifier on the kinetic parameters of wood thermal decomposition is studied. The kinetic parameters (activation energy and preexponent value) are determined by thermal analysis using TGA curves (integral method). A 50 % aqueous solution of monoethanolamine (N→B) trihydroxyborate is used as a modifier; samples of unmodified pine wood are used as controls. The experimental data obtained indicate that the surface modification of pine wood with boron nitrogen fire retardant provides the material with group II fire protection efficiency (modifier consumption-150g/m2). The flame retardant effect of the boron nitrogen modifier is associated with a lower value of the activation energy of its thermal destruction process. The contribution of the entropy factor in reducing the combustibility of modified wood is less expressed. The use of monoethanolamine (N→B) trihydroxyborate as a wood flame retardant is advisable in an oxidizing atmosphere.

Creating an effective wood protectors from boric acid and aminoalcohols

The study of the composition and structure of the reaction products formed in the systems: boric acid – monoethanolamine – water and boric acid – diethanolamine – water at an equimolar ratio of acid and alcohol in an alkaline environment. Using IR-spectroscopy,1H and11B NMR-spectroscopy revealed the formation of monoethanolamine(N→B)-threehydroxyborate and diethanolamine(N→B)-threehydroxyborate, in which the nitrogen and boron atoms are coordinated. In the process of drying the resulting product due to intramolecular condensation, a cyclic structure is formed. In the composition of the boron-nitrogen compounds obtained, the boron atom has a coordination number of four. The resulting boron-nitrogen compounds are effective antiseptics of wood building structures, and also exhibit flame retardant properties. There is boron-nitrogen coordination in the composition of the modifier molecule, due to which nucleophilic attack by water molecules is excluded. Therefore, the modifier is firmly fixed in the composition of the wood and provides durable protection against bio-corrosion and fire.

Solid-state hydrogen rich boron–nitrogen compounds for energy storage

Boron compounds have a rich history in energy storage applications, ranging from high energy fuels for advanced aircraft to hydrogen storage materials for fuel cell applications. In this review we cover some of the aspects of energy storage materials comprised of electron-poor boron materials combined with electron-rich nitrogen elements with the goal of moderate temperature release of hydrogen. The parent compounds of ammonium borohydride, ammonia borane, and diammoniate of diborane provide approaches for storing high gravimetric and volumetric densities of hydrogen. Here we provide a review with a historical perspective and current developments in the area of solid state B and N containing compounds. This review highlights developments in synthesis of ammonia borane and its derivatives over the last 80 years. Thermodynamics and kinetics of hydrogen release in the solid state are discussed. By changing either substituents on the boron and nitrogen atoms or the physical environment by embedding in mesoporous scaffolds, the thermodynamics can be modified to reduce the exothermicity of hydrogen release and minimize formation of volatile impurities. Several mechanistic studies are reviewed identifying the key distinctions between homopolar and heteropolar H2 release. Strategies for economical and efficient regeneration of the hydrogen storage materials via chemical transformation are critically reviewed. The limited efficiency of these chemical regeneration has limited some of the potential applications.

Change in Crystalline Structure of Cellulose Caused by Wood Preservation

Сhemical interaction of cellulose with reactive groups of four-coordinate boron-nitrogen compounds is an intercrystalline process proceeding without destruction of cellulose crystalline structure; probably, the modifier molecules react with easier accessible hydroxyl groups of the amorphous cellulose regions. The formation of B-O-C ether bonds between OH groups of modifiers and more reactive hydroxyl groups of amorphous parts of cellulose results in redistribution of hydrogen bonds and, as a consequence, to rectification of cellulose macromolecules. Thus, when cellulose is treated with compositions based on four-coordinate boron-nitrogen compounds, crystalline structure of cellulose is not disrupted, hence this process can be called a "mild" modification. Such modification does not lead to accelerated aging of cellulose materials, rapid loss of strength and increases durability of wooden structures.

A Study on Capillary-porous Structure of Wood Modified with Boron-Nitrogen Compounds

Capillary-porous structure of wood modified with boron-nitrogen compounds was studies by sorption methods. Specific surface area of the suport was found to be reduced up to three folds.Changes of structure of the wood surface layer treated with aqueas solutions of boric acid and ethanolamines as well as the possibility of forming 4-coordinate boron-nitrogen compounds in situ, directly on the wood surface, were investigated. Stepwise treatment of wood surface with boric acid and ethanolamines in different order was found not to cause significant changes in the capillary-porous structure, which is apparently due to the difficulties of formation of 4-coordinate boron-nitrogen compounds in situ.

Heinrich Nöth (1928-2015).

On June 26, 2015 the “Master of Boron” Heinrich Nöth passed away, only six days after his 87th birthday. Nöth was born on June 20, 1928 as the son of the solo hornist of the Bavarian State Orchestra. Music was an early gift, and his talent meant that a professional career in this field seemed to be the right choice. Nevertheless, at the end of the 1940s he decided to study chemistry at the Ludwig-Maximilians-Universität München (LMU). Although he was always attached to music, chemistry became his profession. After his diploma in 1952, he received his doctoral degree for a thesis on hydrides of Group 13 elements, which he performed under the supervision of Egon Wiberg. After a short period as research officer at ICI in Great Britain, he returned to Munich to begin his habilitation on boron–nitrogen compounds, which he defended successfully in 1962. After four years as associate professor at the LMU, he left Munich to accept the renowned Chair of Inorganic Chemistry at Marburg University. In 1969, he returned to the LMU to succeed Egon Wiberg in the Chair of Inorganic Chemistry, a position he held until he retired in 1996. Heinrich Nöth had started his own family already before finishing his dissertation. In 1953, he married Erika and they had two daughters. Nöth enjoyed his family life, and his seven grandchildren were a counterpart to his commitment for science. Chemistry was his life. He worked on hydrides and elemental hydrogen compounds as well as on nitrogen compounds of lithium, beryllium, aluminum, and tin. But his main focus was on boron and its manifold chemistry. He synthesized low-coordinate boron compounds such as boron cations, aminoiminoboranes, methylidenboranes, and phosphanylidenboranes. Already at an early stage, his interest was in compounds with boron–transition-metal bonds, which resulted in a rhodium-catalyzed hydroboration reaction with catecholborane; even today this procedure still inspires metal-catalyzed borylation reactions. Boron-containing heterocycles such as borazines, borafluorenes, and strained borabicyclobutane derivatives were studied in his laboratories. Boron–hydrogen chemistry and redox chemistry of tetrahydridoborates played a prominent role in his research, and the reaction mechanisms of these reactions were elucidated. Electron-precise open-chain and cyclic oligoaminoboranes became accessible, and a cyclohexaborane was a particular highlight. 11B NMR spectroscopy was important to Nöth as a tool in boron chemistry, but single-crystal X-ray diffraction was really his passion. A burning light in the diffractometer room of the institute after midnight indicated Nöth at work, and he practiced this technique even when he was in his eighties. The results of his research are summarized in more than 800 publications and 16 patents. During his active career, Nöth had more than 150 doctoral students. However, research was not his only important undertaking—he was a fascinating teacher and his experimental lectures on inorganic chemistry, the “Nöth show”, were treasured by many students. It is not sufficient to describe Nöth as a dedicated researcher and teacher. He recognized the necessity to promote the natural sciences, specifically chemistry, in society. His personality and his gift for combining various interests and finding efficient solutions allowed him to hold several influential positions, not only in university administration and the Deutsche Forschungsgemeinschaft (German Research Foundation). He was President of the Gesellschaft Deutscher Chemiker (GDCh; German Chemical Society) for two terms (1988–1989 and 1992–1993), and he was also elected President of the Bavarian Academy of Sciences for two consecutive terms (1998–2005). Here he exerted formative influence on the visibility of science in Germany. Nöth was Editor-in-Chief of Chemische Berichte from 1976–1997, and was Senior Editor of its successor, the European Journal of Inorganic Chemistry, from 1997–1998. In addition, he was member of the advisory boards of 11 scientific journals. Numerous honors followed, and he was elected to many academies and was made an honorary member of several chemical societies, both national and international. In 1991 he was appointed to the Bavarian Maximilian Order for Science and Art, the highest award for scientific achievements in the Free State of Bavaria. In 2009, his services to natural sciences were honored with the Officer’s Cross of the Order of Merit of the Federal Republic of Germany. As permanent guest professor at the CINVESTAV in Mexico City he promoted not only scientific exchange, but had a strong commitment to children’s aid in Mexico. All these activities were supported by his family, and he liked to relax in his house near the Chiemsee, which was always a very welcome final destination for group excursions into the Bavarian mountains. With the passing of Heinrich Nöth, chemistry has lost one of its most influential characters over the last few decades.

Facile Synthesis and Photocatalytic Properities of Mini Nanoparticle CdS Quantum Dots/Boron and Nitrogen Co-Doped TiO<sub>2</sub> Transparent Photocatalyst Emulsion

CdS quantum dots/ Boron and Nitrogen co-doped TiO2 photocatalyst emulsions were synthesized by a complexation-controlled hydrolysis method at room temperature. Boron compounds and Nitrogen compounds were added to TiO2 precursor solution, and CdS quantum dots were attached to TiO2 particles surfaces by using chemical reaction. The hybird composite photocatalysts were characterized by XRD, UV-Vis. Their photocatalytic properties were evaluated through the degradation of acid red 3R dye. The results indicate that when TiO2 emulsion add to Boron ions, Nitrogen ions, and CdS quantum dots, the photocatalytic performance of the emulsion is the best.

Facile Synthesis and Photocatalytic Properities of PbS Quantum Dots/Boron and Nitrogen Co-Doped TiO<sub>2</sub> Transparent Photocatalyst Emulsion

PbS quantum dots/ Boron and Nitrogen co-doped TiO2 photocatalyst emulsions were synthesized by a complexation-controlled hydrolysis method at room temperature. Boron compounds and Nitrogen compounds were added to TiO2 precursor solution, and PbS quantum dots were attached to TiO2 particles surfaces by using chemical reaction. The hybird composite photocatalysts were characterized by nanoparticle size analyzer. Their photocatalytic properties were evaluated through the degradation of acid red 3R dye. The results indicate that when TiO2 emulsion added to Boron ions, Nitrogen ions, and PbS quantum dots, the reflux time is 15 min, the photocatalytic performance of the emulsion is the best.

Triplet-Energy Control of Polycyclic Aromatic Hydrocarbons by BN Replacement: Development of Ambipolar Host Materials for Phosphorescent Organic Light-Emitting Diodes

In this work, we achieved the triplet-energy control of polycyclic aromatic hydrocarbons (PAHs) by replacing the Carbon−Carbon (CC) unit with a Boron−Nitrogen (BN) unit. Time-dependent density functional theory calculations suggested that the insertion of the BN unit may cause localization of the singly occupied molecular orbitals 1 and 2 (SOMO1/SOMO2) in the triplet state, which in turn can reduce the exchange interaction and dramatically increase the high singlet–triplet excitation energy (ET). The PAH containing the BN unit, 4b-aza-12b-boradibenzo[g,p]chrysene, showed a large ET value and ambipolar carrier-transport abilities. The introduction of a phenyl substituent on 4b-aza-12b-boradibenzo[g,p]chrysene slightly reduced the ET values and the carrier-transport abilities, but increased the glass-transition temperatures. On the basis of these findings, we successfully built phosphorescent organic light-emitting diodes using the BN compounds as host materials, which exhibit a superior performance over the device using a representative host material, 4,4′-bis(N-carbazolyl)-1,1′-biphenyl, not only in terms of efficiency but also in terms of device lifetime. This study demonstrated the potential of BN-embedded polycyclic aromatics in organic electronics and showed a novel strategy to achieve triplet-energy control of aromatic compounds.

Production of Bio-Resistant Wood Materials through the Modification of Wood by Boron-Nitrogen Compounds

Modifying of the surface of pine wood with aqueous solutions boron-nitrogen compounds was empirically found to provide a 100% biological stability of wood for at least 20 years. Durability of the protective effect of the modifiers developed is due to the formation of hydrolytically stable compounds on the surface of the wood.

Изучение токсичности боразотных модификаторов поверхности древесины

Boron-nitrogen compounds (BNC) have been successfully used to create bioand fire-protective compositions for wood. Within the framework of this study, our aim was to assess the toxicity of the boron-nitrogen compounds by bioluminescent method with the use of environmental control device Biotox-10M and highly sensitive biosensor Ecolum. We also defined toxicological parameters EC20 and EC50 and concluded, that all the wood preservation compounds are highly toxic, whereby, it is advisable to use them for external protection of wooden structures. As a result of BNC toxicity assessment, it is necessary to consider that any effective bioand fireprotectives, will be highly toxic. Our researches stated, that BNC protective compositions are highly toxic and, therefore, it is possible to conclude their applicability for external wood processing.

Biostability of Wood in the Presence of Boron-Nitrogen Compounds

We have developed new compositions based on tetravalent boron-nitrogen compounds (amine borates), which are able to increase the bio-resistance and flame-retardancy of wood at the surface modification. Previously, it was shown that the obtained amine borate formed hydrolytic stable compositions with lignin and carbohydrates, which are the basis wood. So we can expect a long-term protective effect caused by the developed compositions.The full-scale tests conducted on bars in stand mycological site of MNIIS Dame Bay (Tropical Research Centre, Far East branch office, Nha Trang, Vietnam). Test samples were subjected to a pine wood size 50x50x10mm, impregnated under standard conditions of boron-nitrogen compounds, as well as control samples of pine wood of the same size. The tests lasted 36 months, inspections were carried out every three months. According to the significant prepared by Tropical Research Centre laboratory changes in the state of modified pine wood samples for three testing years did not happen. Samples impregnated boron-nitrogen compounds, did not change its colour. Fouling fungi were observed. Control samples of the same unmodified wood completely overgrown by fungi.