Preparation of amines
Preparation of amines. Jun 1, 1990 · Highly Diastereoselective and Enantioselective Preparation of Homoallylic Amines: Application for the Synthesis of β-Amino Acids and γ-Lactams. Many amines have common names that are used by IUPAC, for example the primary arylamine (C 6 H 5 NH 2) is called aniline. In formal terms, amines are the derivatives of ammonia (NH₃), wherein one or more hydrogen atoms have been replaced with a substituent like the groups of alkyl or aryl. Example- Nitrobenzene converted to aniline in presence of tin (Sn), concentrated HCl and NaOH. This one-pot protocol works efficiently at room temperature using ammonia borane as the reductant and is applicable to a wide range of substrates Jul 25, 2022 · Amines are the class of organic compounds obtained by replacing one, or more hydrogen atoms of ammonia with alkyl groups. Amines as bases . Preparation of Primary Amines Although direct alkylation of ammonia (large excess) by alkyl halides leads to 1º-amines, alternative procedures are preferred in many cases. Amines are aliphatic and aromatic derivatives of ammonia. They all require more than one step and you may select the desired regioisomer (for example the para product from an ortho, para mixture) when needed. Nov 1, 2000 · Examples of a new class of onium salts bearing the tetrafluoroborate anion (BF 4 - ) were prepared by neutralization of the corresponding amines. The disadvantage of this method is the polyalkylation which occurs because the newly forming amines react with the initial alkyl halide. DeSoto, S. The currently commercialized polyether amines contain a series of monofunctional, difunctional, and trifunctional materials, with molecular weight varying from May 12, 2018 · This organic chemistry video tutorial provides a basic introduction into synthesis reactions of amines. It is also characterized by various properties that are based on carbon connectivity. Singaram, J. These iminium ions were generated fr … View Answer. The importance of the lone pair on the nitrogen in the reactions of amines as Mar 18, 2020 · Reductive aminations are an essential class of reactions widely applied for the preparation of different kinds of amines, as well as a number of pharmaceuticals and industrially relevant compounds. As a result a salt is formed and the following reaction takes place: Alkyl halide (R-X) + Ammonia (NH3) → Salt (R-NH3 + X–) A reverse reaction takes place and a primary amine is formed. The aminium radicals are generated by a two-step sequence which involves N-chlorination of alkyl amines and subsequent reductive N−Cl cleavage. The method uses phthalimide, which contains a protected form of nitrogen that participates in Apr 13, 2022 · Subscribe to Ekeeda Channel to access more videos https://www. R—CH 2 NH 2. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid. Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Study with Quizlet and memorize flashcards containing terms like What conditions are required for the preparation of primary amines from halogenoalkanes?, Give the general (word) equation for the reaction of a halogenoalkane with ammonia, What is the name of the mechanism for the the reaction between a halogenoalkane and ammonia? and more. RCOX +H2NR′ → RCONHR′ + HX (24. Here is a list of topics:1. . b) One Amides can be converted to 1°, 2° or 3° amines using LiAlH 4 Reductive Amination 23. a substance which combines with hydrogen ions. Aromatic amines are also known as arylamines. Amines can be prepared by reduction of Aromatic nitro compound. Learn how to prepare amines by alkylation of ammonia, reduction of alkylazides, nitriles, amides, nitrocompounds, and reductive amination of aldehydes and ketones. This is the Lewis theory. Do you know why toilets smell so bad? The smell is because 6 days ago · Amines. Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 1962, 11 (10) , 1731-1740. Amides generally are formed from acid chlorides, acid azides, acid anhydrides, and esters. (There is a shift of alkyl group to the nitrogen) Step 5. Amines are functional groups and compounds holding a basic nitrogen atom with a lone pair. Learn the concepts of Class 12 Chemistry Amines with Videos and Stories. These may respectively be called as alkylamines and arylamines. Preparation of primary amines (RNH. CH 3-CH(NH 2)-CH 2-CH 3 - Butan-2-amine 3. Preparation of functionalized primary chiral amines and amides via an May 17, 2018 · Benzylic amines are valuable compounds with important applications in areas including pharmaceuticals and agrochemicals. Preparation of Amines. b) Simple distillation. 1) RH + HONO 2 → RNO 2 + H 2 O by displacement reactions with nitrite ions, RX +NO−2 → RNO2 +X− (24. The compound shown is trimethylamine which reacts with iodomethane (alkyl halide) to form a quaternary ammonium salt [ (CH 3 )4N + ]I –. 2]nonane and exo-6-amino-8-azabicyclo[3. CH3CH2Br + NH3 → CH3CH2NH+3 Br− (1) (1) C H 3 C H 2 B r + N H 3 → C H 3 C H 2 N H 3 Reductive amination. Phenylamine is an organic compound consisting of a benzene ring and an amine (NH 2) functional group. 1) (24. 8: Basicity of Aromatic Amines. Alkyl halides react via S N 2 with ammonia (NH 3) and amines as the attacking nucleophile. e. 1002/chem. Step 2 - Nitrobenzene is reduced with hot tin (Sn) and concentrated Halides react with amines in the following order: RI>RBr>RCI. Methyl Amine. Devise a synthesis of each of the following compounds using an arene diazonium salt. H 2 N-CH 2-CH 2-CH 2-NH 2 - Propane-1, 3-diamine. Because they have a significant resonance form where there is a negative charge on the alpha carbon, they are nucleophilic. met Jan 31, 2018 · There is a clever workaround to this – at least for the synthesis of primary amines. Diazonium salts can be isolated in the crystalline form but are usually used in solution and immediately after preparation, due to rapid decomposition on standing even with little ambient heat. Explanation: Tertiary amines are formed as the ammonolysis of alkyl halides proceeds to form 1° and 2° amines, which further reacts with the alkyl halide. the most widely used method for the preparation of amines is the May 23, 2021 · Amines are classified as primary, secondary, or tertiary by the number of hydrocarbon groups attached to the nitrogen atom. Explain the different methods of preparation Amines. To absorb all of it, you should use the three subsections indicated in the reading: electrophilic aromatic substitution and overreaction of aniline (Objectives 1 and 2), the preparation of diazonium salts and the Sandmeyer reaction (Objectives 3 and 4), and diazonium coupling reactions (Objective 5). Primary amine: Amines containing only one alkyl group attached to the nitrogen. 200401295 Preparation of primary aliphatic and alicyclic amines from thiophene derivatives. Dec 1, 2023 · Primary amine compounds with high nucleophilicity are crucial, high-value chemicals. Oct 8, 2018 · Herein we demonstrate that RuCl 2 (PPh 3) 3 is an efficient and highly selective homogeneous precatalyst for reductive amination, allowing the preparation of a variety of primary amines of Jan 20, 2024 · Preparation of Amines from Halogenoalkanes. Acid chlorides can react with amines to form amides. Because these are uncharged nucleophiles, it means that the initial S N 2 product has a positive charge on nitrogen, so an additional acid-base step is needed to produce an uncharged product. It is not practical to prepare them directly from an amine and a Jan 4, 2021 · Amines are a class of compounds of essential importance in organic synthesis, pharmaceuticals and agrochemicals. Alkylation is one of the methods used to prepare amines. 19. There are other methods of preparing amines, including reduction of nitro to amine mechanism, Gabriel phthalimide synthesis, and preparation of amines by reduction of amines. They can be 1 o , 2 o or 3 o amines depending on how many hydrogen atoms are replaced. 11. 2: Preparation of Amines - A Review is shared under a CC BY-NC-SA 4. Reductive Amination. Though these compounds have a pungent smell, they have enormous use in chemistry and in daily life. Moreau, D. Introduction to Amines. It’s called the “Gabriel Synthesis”. D. Preparation of Primary Amines Although direct alkylation of ammonia by alkyl halides leads to 1º-amines, alternative procedures are preferred in many cases. Jan 10, 2018 · The main chain of polyether amine is polyether and its terminal active functional groups are amines. 9: Preparation of Amines by Reduction. Reduction of nitriles. The reaction happens in two stages. Example: Amines can be produced in two ways. 3. Org. The cascade amination/cyclization of N-arylacrylamides with alkyl amines under visible-light photoredox catalysis is realized via intermediacy of aminium radicals. The second step is the reduction of the imine to an amine using an reducing agent. Several Bacillus megaterium strains from our culture collection as well as several soil isolates were found to have the desired activity for the Preparation of Primary Amines Although direct alkylation of ammonia by alkyl halides leads to 1º-amines, alternative procedures are preferred in many cases. 24. This basicity is due to the unshared electron pair on the nitrogen atom. 1b) 4,5,6,7,8,9,10. Abbott, N. Amines play a variety of roles in living creatures, including bioregulation, neurotransmission, and predator protection. Eagon, B. Since the counter anion in most 4º-ammonium salts is halide, this is often replaced by the more basic hydroxide ion through reaction with silver hydroxide (or silver oxide). method of preparation of amines || chemical reaction of amines || amines b pharmacy #pharmacyin this video we cover1. , 2009 , 74, 1964-1970. CH 3-NH 2 - Methanamine 2. The resulting hydroxide salt must then be heated (100 - 200 ºC) to effect the E2-like Reductive Amination. Preparation of Aromatic amines. This process of making the quaternary salt through the direct alkylation method is called exhaustive alkylation. Alkyl azides, nitriles, amides, and nitroarene can be reduced to the corresponding amines. Aryl amides derived from each series were prepared and tested in an α7 nicotinic acetylcholine receptor assay as part of a Jan 23, 2023 · Nitriles can be converted to 1° amines by reaction with LiAlH 4. The aqueous layer is then treated with a base (NaOH) to regenerate the amine and NaCl. Other primary amines tend to be named as alkanamines. What are the preparation methods of amines? The preparation methods of amines include alkylating ammonia with a halogenoalkane or an alcohol, and also reducing a nitrile or amide. An amine is generally a functional group with a nitrogen atom having a lone pair. Above 5°C, it will decompose to give phenol and N 2. Penney, B. Haddenham, L. Using lithium aluminum hydride to reduce nitriles creates primary amines (LiAIH 4) or Catalytic hydrogenation of nitriles produces primary amines. To learn more about Amines Structure, Nomenclature, Classification, Preparation, Basicity with FAQS and videos, Visit BYJU'S for more content. 1: Amines - Structures and Names is shared under a CC BY-NC-SA 4. Once stabilized by a Lewis acid-base complexation the imine salt can accept a second hydride to form a dianion. Gabriel synthesis is the most preferred method to exclusively make primary amines. Introduction. com/c/Ekeeda?sub_confirmation=1#OnlineVideoLectures#EkeedaOnlineLectures#EkeedaVideoLec This reaction is used for ascent of amine series, i. • 2° amine: Two hydrogen atoms of NH 3 are replaced by alkyl or aryl groups. Lee, C. , 3. NH 3 R NH 3 R NH 2 R R N H R R Jun 26, 2023 · In IUPAC system, amines are named as alkanamines, derived by replacement of 'e' of alkane by the word amine. Nucleophilic Substitution Preparation of amines from the reduction of aromatic nitro compounds is an important topic in organic chemistry. They can be made by amination of oxygen-containing functional group compounds, such as aldehydes, ketones, and alcohols, or by reduction of nitrogen-containing compounds containing cyano, nitro, amide, and oxime groups. Screening was carried out to identify strains useful for the preparation of (R)-1-cyclopropylethylamine and (R)-sec-butylamine by resolution of the racemic amines with an (S)-specific transaminase. Elimination reactions of 4º-ammonium salts are termed Hofmann eliminations. May 30, 2008 · Screening was carried out to identify strains useful for the preparation of (R)-1-cyclopropylethylamine and (R)-sec-butylamine by resolution of the racemic amines with an (S)-specific transaminase. Step 1- Benzene undergoes nitration with concentrated nitric acid (HNO 3) and concentrated sulfuric acid (H 2 SO 4) at 25 to 60 o C to form nitrobenzene. 7 Reactions of Amines. 1]octane, 3-amino-1-azabicyclo-[3. The first step is the nucleophiic addition of the carbonyl group to form an imine. Reduction of nitro compounds Jul 31, 2021 · Table 24-1: Derivatives and Reactivity of Carboxylic Acids Commonly Used in Amide Formation. The use of the acetyl functional group is widespread, including drug research, the preparation of pharmaceuticals, polymer chemistry and agrochemical applications [5,6,7,8,9,10]. Amides can directly be converted into their corresponding amines. On the basis of number of hydrogen atoms replaced in NH 3 molecule, amines are categorized into three types: • 1° amine: One hydrogen atom of NH 3 is replaced by an alkyl or aryl group. Like ammonia, the nitrogen atom of amines is trivalent and carries an unshared pair of electrons. org/10. Apr 23, 2020 · 1. Amines, like ammonia, are weak bases (K b = 10 −4 to 10 −6 ). https://doi. The alkyl group is named as an alkane ( prefix+ane) and –e ending is replaced with the suffix -amine. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the Preparation of Primary Amines Although direct alkylation of ammonia by alkyl halides leads to 1º-amines, alternative procedures are preferred in many cases. Amines are prepared by following methods: 1. Aromatic amines can be prepared by reduction of Aromatic nitro compound. The importance of amines, their preparation, and reactions can be understood through the fact that many vitamins are also built from various types of amino acids. Reductive amination of aldehydes and ketones. Aniline is usually purified by which of the following method? a) Steam distillation. Nitrobenzene, C 6 H 5 NO 2, can be reduced to phenylamine, C 6 H 5 NH 2, according to the following two-stage reaction: The two-stage reduction reaction of nitrobenzene to phenylamine. Enamines are formed from the reaction of a secondary amine with an aldehyde or ketone. 2) RX + NO 2 − → RNO 2 + X − and by oxidation of primary amines, RNH2 [O] RNO2 Gabriel synthesis is used for the preparation of primary amines. Amines are classified as primary, secondary, or tertiary based upon the number of carbon‐containing groups that are This set of Organic Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Preparation of Aromatic Amines”. Halogenoalkanes are heated with ammonia in ethanol in a sealed tube. Chemistry - A European Journal 2005, 11 (15) , 4387-4395. 0 license and was authored, remixed, and/or curated by LibreTexts. Chem. Nitrogen orbitals in amines are, therefore, s p 3 hybridised, and the geometry of amines is pyramidal. youtube. Via alkylazide reduction. Preparation of amines . (A simple hydrolysis of an imine gives us the amine) Apart from this, amides can be dehydrated by P 2 O 5 to their corresponding nitriles and nitriles can then be reduced. Dec 1, 2020 · Accordingly, this investigation focuses on the synthesis of nanoporous carbonaceous promoters (NCPs) derived from commercial activated carbon samples with high surface area and different surface functionalities, which make them unique candidates for the preparation of amine-based nanofluids. This is the Bronsted-Lowry theory. Amines are ammonia-based organic compounds that have one or more alkyl or aryl groups attached to the nitrogen atom. Step 3. 1 - Preparation of Amines Amines are produced when one or more of the hydrogen atoms in ammonia is replaced with an organic group . Mar 27, 2024 · Aldehydes and ketones can be converted into 1 o, 2 o and 3 o amines using reductive amination. For example: Sep 10, 2001 · Syntheses of amines have perhaps received more attention than the preparation of many other functional groups in organic chemistry. Note – this is a significant We report a convenient one-pot preparation of polyfunctional tertiary amines, including various biorelevant phenethylamines or ephedrine derivatives, via the reaction of new functionalized iminium ions with a variety of zinc and magnesium organometallic reagents. 2. Conversion of Alkyl Halid For amines one can take advantage of their basicity by forming the protonated salt (RNH 2+ Cl − ), which is soluble in water. an electron pair donor. Renewable biomass resources contain a large number of C–O and C═O bonds that can Mar 13, 2009 · Three new azabicyclic amines, namely exo-3-amino-1-azabicyclo[3. These methods require two steps, but they provide pure product, usually in good yield. Answer: c. Based on the number of alkyl groups present in the compounds, amines are classified as primary secondary and tertiary amines. May 2, 2018 · The N-alkylation of primary amines (1) with alcohols (ROH) is a highly efficient method for preparing secondary alkylamines (2) and tertiary alkylamines (3, Fig. See examples, mechanisms, and products for each method. Nov 29, 2022 · Ch#17 |Lec#7 |Preparation Of Amines, Physical properties, Reactivity, Class 12 May 24, 2010 · Enamines – formation, properties, reactions, and mechanisms. An amine with one carbon attached to nitrogen is a primary amine, an amine with two is a secondary amine, and an amine with three is a tertiary amine. for preparation of amines containing one carbon atom more than the starting nitrile. 2. The reactions are environmentally benign with H 2 and NH 3 A simple and efficient protection procedure is general and regioselective for the preparation of mono-N-Boc, N-Cbz, N-Fmoc or N-Alloc aromatic amines in high yield without affecting aliphatic amino groups and other functionalities. Jan 23, 2023 · Making a primary amine. Reductive amination. The answers to these problems can be found under the arene diazonium salts post. Study Notes. The direct alkylation of 1º or 2º-amines gives a more substituted product does not proceed cleanly. Which is the best method for preparing a primary amine? In industry, amines are generally made by alkylating ammonia using an alcohol thanks to the low cost and high • Substituted amine followed by the name of anion Putting vinegar (acid) on fish to remove odor • Results in the formation of an odorless amine salts All amine slats are water soluble • This is why drugs of amines are administered in the form of amine salts 17. Primary aromatic amines, such as aniline (phenylamine) forms a more stable diazonium ion at 0–5°C. This is just like ammonium bromide, except that one of the hydrogens in the ammonium ion is replaced by an ethyl group. But do you want to know what amines are? And what are their properties and uses? Dive into the articles below. The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Phthalimide on treatment with ethanolic potassium hydroxide forms potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis produces the corresponding primary amine. Aromatic Amine Basics. N-acetylation is a widely used chemical reaction in general organic chemistry to build an acetyl functional group on an amine compound [1,2,3,4]. Zacharie, Synthesis, 2009, 283-289. Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. 15: Preparation of 1° Amines: Gabriel Synthesis. Examples- aniline, toluidines, phenylenediamine, etc. method of preparation of amines2. An amine is a derivative of ammonia in which one, two, or all three hydrogen atoms are Q-Chat. 1. This method greatly simplifies the preparation of many organic molten salts. Aldehydes and ketones can be converted into 1 o, 2 o and 3 o amines using reductive amination. 1007/BF00920270 May 29, 2023 · Amines are the derivatives of ammonia. The reaction takes place in two parts. Several Bacillus megaterium strains from our culture collection as well as several soil isolates were found to have the desired activity for the Amines are classified as primary, secondary and tertiary amine according to the number of substitution (alkyl/aryl) groups attached to the nitrogen. Amines are a type of organic compound in which an alkyl/aryl group replaces one or more hydrogen atoms in ammonia molecules (s). V. In the Gabriel synthesis we start with a molecule called “phthalimide”. Pasumansky, J. The smell is because of Ammonia and the compounds of ammonia called Amines. 2) (24. ) via the SN2 reaction. Its excellent comprehensive performance is formed by a special molecular structure. Jul 31, 2021 · Preparation of Nitro Compounds Nitro compounds can be prepared in a number of ways, including the direct substitution of hydrocarbons with nitric acid, RH +HONO2 → RNO2 +H2O (24. 1 With the growing repertoire of biologically relevant nitrogenous molecules, so is the need for efficient synthetic methods to prepare amines as useful intermediates. Amines L1 | Preparation Of Amines | Class 12 | JEE & NEET 2021 Chemistry | Pahul Sir - Advanced Problem Solving And Lecture On Amines | JEE & NEET 2021 For C A mild and convenient reductive amination protocol for the synthesis of structurally diverse secondary and tertiary amines as well as N-methylated products under metal-free conditions is presented. Their preparation from halogenoalkanes (haloalkanes or alkyl halides) and from nitriles. Synthesis of Amines 26 – Preparation of Primary Amines by the Hofmann and Curtius Rearrangements • An unsubstituted amide can be converted to a primary amine by formal loss of the amide carbonyl through the Hofmann rearrangement (also called the Hofmann degradation) • The first two steps of the mechanism result in N-bromination of the amide Preparation of Amines via Azides. A wide range of nitriles were reduced to primary amines by 1. This reaction produces amines with one more carbon atom than the original amines ascending in the anime series. Each Preparing Aromatic Amines. d) Extraction with a solvent. The easiest way of looking at the basic properties of amines is to think of an amine as a modified ammonia molecule. In an amine, one or more of the hydrogen atoms in ammonia has been replaced by a hydrocarbon group. Though catalytic hydrogenation can Organic Chemistry Questions and Answers – Preparation of Amines – 1. 21. An introduction to amines including the various types of amine (primary, secondary and tertiary) and their physical properties. Apr 17, 2015 · We report a convenient one-pot preparation of polyfunctional tertiary amines, including various biorelevant phenethylamines or ephedrine derivatives, via the reaction of new functionalized iminium ions with a variety of zinc and magnesium organometallic reagents. Alkylation of ammonia. (Bromine leaves and we have an electron deficient nitrogen) Step 4. c) Vacuum distillation. The –e ending is not removed for diamines. The amine formed from an amide by means of bromine and alkali has how many number of carbon atoms? a) Same number of C atoms as that of amide. Reduction of amides. The Gabriel Synthesis Uses A “Protected” Amine (Phthalimide) In An S N 2 Reaction That Does Not Undergo Over-Alkylation. Elimination reactions of 4º-ammonium salts are termed Hofmann eliminations, where the products are a tertiary amine and a alkene. In the first stage, a salt is formed - in this case, ethylammonium bromide. 3. Gabriel synthesis. One way to avoid the alkylation of the primary amine is using an azide salt to convert the R-X alkyl halide or R-Oms/R-OTs intermediate, and then reduce the alkyl azide: Azide is a good nucleophile and the reaction goes via SN 2 reaction so using a polar aprotic solvent such as DMF or DMSO is beneficial. They are hydrolyzed with strong acid. Amines resemble ammonia structurally where nitrogen can bond up to 3 hydrogen atoms. For example: CH 3 NH 2. 9. 6. This section contains a considerable amount of new information. The salt will extract into the aqueous phase leaving behind neutral compounds in the non-aqueous phase. The largest ionic conductivity was observed in 2 In the previous post, we talked about the preparation of amines and one of the possible approaches was the direct S N 2 reaction between an alkyl halide and a primary amine. Direct alkylation of ammonia or a primary amine with an alkyl halide gives polyalkylated amines along with a quaternary ammonium salt through successive S N 2 reactions. On the basis of the number of alkyl groups present in the compounds, amines are classified as primary secondary, tertiary. Reduction of Amides. Perron, S. It can be produced in a three-step synthesis reaction followed by the separation of phenylamine from the reaction mixture. 1) RCOX + H 2 NR ′ → RCONHR ′ + HX. May 28, 2024 · PDF Summary - Class 12 Chemistry Amines Notes (Chapter 13) Introduction. 1]octane, have been designed and prepared as isosteres of 3-aminoquinuclidine. 8 Preparation of Amines and Quaternary Ammonium Salts Preparation of amines Preparations: Amines. This set of Organic Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Preparation of Amines – 1”. This reaction is carried out by treating the amide with a mixture of base and bromine (KOH + Br 2). The most Jan 26, 2023 · Summary. During this reaction the hydride nucleophile attacks the electrophilic carbon in the nitrile to form an imine anion. Aromatic amines are Aromatic hydrocarbons where one hydrogen molecule of the aromatic ring is replaced by an amino group. P. Previous Preparations: Halo Acids, α‐Hydroxy Acids, and α, β‐Unsaturated Acids. Some of the resulting neutralized amines displayed an ionic conductivity greater than 10 -2 S cm -1 at room temperature. 2 equiv of ammonia borane under thermal decomposition conditions without any catalyst to primary amines in very good yields. Reduction of nitrocompounds. The dianion can then be converted to an amine by 19. Study with Quizlet and memorize flashcards containing terms like Preparation of amine From Alkyl Halide, Preparation of amine from a carboxylic acid, Preparation of aniline from benzene and more. Oct 13, 2021 · We have recently explored the synthesis and reactivity of amine boranes (R 3 NBH 3) and a concept of the nucleophilicity of the B-H and B-B bonding pair electrons has been proposed 42,43,44,45,46 3. xo py sg yf vy iq rl ly lw ha