Also known as the pearson acid base concept, hsab is widely used in chemistry for explaining stability of. Pearsons hsab theory is in direct contradiction with fajans rules. The c3 and o2ethylations were examined to find out whether the marcus or hsab theory can explain the ambident reactivity of this nucleophile. Determination of relative reactivity of hsab complexes using dft theory salah aldin jassim humadi department of chemistry, college of science, university of diyala. Hsab principleapplicationspearsons hard soft acid base. The pdf file you selected should load here if your web browser has a pdf reader plugin installed for example, a recent version of adobe acrobat reader if you would like more information about how to print, save, and work with pdfs, highwire press provides a helpful frequently asked questions about pdfs alternatively, you can download the pdf file directly to your computer, from where it. Polarizability is an inherent characteristic of electron distribution in atoms or molecules. Crystal field theory cft describes the breaking of orbital degeneracy in transition metal complexes due to the presence of ligands. The pdf file was posted to the course moodle, and students were asked to annotate their copy either in printed or electronic form to highlight terms or sections of text that they did not understand. The journal of organic chemistry 2015, 80 3, 16611671. Co 2 is considered as a hard acid, while primary and secondary amines are hard bases.
The impact of the new idea was immediate, however, over the years the hsab principle has rather fallen by the wayside. Cft qualitatively describes the strength of the metalligand bonds. The base ch 2 4 o is considered hard while ch 2 4 s is soft. If youre behind a web filter, please make sure that the domains. Lower simon fraser university contents 1 acids 2 1.
An interaction of co 2 and amino groups is explained by the hard soft acid base hsab theory 21, 22. Hsab is an extremely useful qualitative theory that enables predictions of what adducts will form in a complex mixture of potential lewis acids and bases. Pdf hardsoft acidbase hsab principle and difference. Hard applies to species which are small, have high charge states the charge criterion applies. Syllabus and tentative course outline for ch 451551. Iso poly and heteropoly acids and salts pdf download lazheawal interactions between two hard or soft acids or bases are stronger than ones between one hard and one soft acid or base. Chemical hardness is one of the highly useful concepts which enable chemists to understand reactivities without reference to large supercomputers and databases. For example, the later predict the nature of beryllium salts to be more covalent. Geochemical ore classification nickel ni, zinc zn, and copper cu ores are exclusively found as sulfides, whilst aluminum al and calcium ca are usually found as oxide and carbonate, respectively. The hsab principle and extended solubility theory alan beerbower energy center, university of california, san diego, lajolla, calif. Hsab concept is an initialism for hard and soft lewis acids and bases.
The hsab principle more quantitative aspects sciencedirect. Week of september 26th mredi tour, september 28th strain and stability ch 2. It assigns the terms hard or soft, and acid or base to chemical species. Received april 18, 1983 193 a semiquantitative approach to the prediction of. Originally developed as an intuitive, qualitative concept, it is today firmly based on and justifed by quantum chemistry. On opening the book cover you will find a periodic table and a list of elements and atomic masses. Synthesis, structure, and adsorption properties dongmei wanga, yuxiao zhanga, jiali gaoa, genwu geb, and chunxia lia a key laboratory of the ministry of education for advanced catalysis materials. Jensen department of chemistry, university of wisconsin, madison, wis. Accordingly, cysteine is an unfavorable candidate for hd adduction since the corresponding sulfhydryl thiol group is a soft nucleophile. Hard applies to species which are small, have high charge states the charge criterion.
Theory to,download application of hard soft acid base hsab theory to,free download application of hard soft acid base hsab theory to,application of hard soft acid base hsab theory to pdf ebooks, read application of hard soft acid base hsab theory to. Hsab theoryrelative nucleophilicity and electrophilicity 5. Hardsoft acidbase hsab principle and difference in. The hsab concept has been widely used to study the physics and chemistry of the solid state, see, for example, ref. Hsab theory classifies reacting species as either relatively hard or soft, based on polarizability. In this article, the notorious negative occupation problem afflicting the ekt. Applications of the hardsoft acidbase hsab principle. Theory of hard and soft acid and bases hsab sruthi p k 2. For some of these questions, you need data from the appendices of inorganic chemistry, fourth edition by c. There is a theory named as hard and soft acidbase theoryhsab. Several studies have been reported the applicability of local hardsoft acidbase hsab principle in examining the site selectivity in a molecule9. Based on the strength of the metalligand bonds, the energy of the system is altered. First we point out the important link between the absolute hardness of acidandbase and the average energy gap.
View notes lecture 11 lewis hsab theory from chem 2030 at rensselaer polytechnic institute. However it is possible to quantify this concept based on klopmans fmo analysis using interactions between homo and lumo. We attempt to extend the hardsoft acidbase hsab principle for the reactions in solutions to interactions in solids. Ralph pearson introduced the hard soft lewis acid base hsab principle in the early nineteen sixties, and in doing so attempted to unify inorganic and organic reaction chemistry. Week of october 2nd strain and stability ch 2 thermochemistry. If youre seeing this message, it means were having trouble loading external resources on our website. This may lead to a change in magnetic properties as well. We believe the new theory we established here, the socalled 2b theory that combines the hsab and bifunctional mechanisms, is a fundamental principle of electrochemistry underscoring the interface. Hsab welcome bbq sept 02 come celebrate labor day weekend with hsab we are hosting our annual welcome bbq. Scheme vii the outcome of fc reactions on the basis of hard and soft acid base principle hsab. Determination of relative reactivity of hsab complexes. Introduction to inorganic chemistryacidbase chemistry.
Lack of space prevents further discussion of many new applications. Introduction the hsab concept is an acronym for hard and soft acids and bases. Ambidentate ligand is a mono dentate ligand which can coordinate to metal through more than one coordinating atoms. Mp2 is a convenient way to calculate vertical ionization potentials directly. Introduction to acidbase chemistry a chem1 reference text stephen k. At the end of the class discussion, they turned in either a printed or an electronic copy of the annotated paper.
Abstract based on the density functional theory dft, the stability of molecular complexes has been predicted according to hardsoft acid base hsab theory. Also known as the pearson acidbase concept, hsab is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways. Pearson 1963 hard acids prefer to associate with hard bases, and soft acids prefer to associate with soft bases. This can be refined further by noting that for some metal ions, their chemistry is dominated by size and charge, while for others it is. In this study, density functional theory dft based reactivity descriptors have been used to understand site and regioselective reactions79. An introduction to the quantum theory for chemists. Hard soft acids bases hsab principle and organic chemistry. However, for those who wish to learn more about density functional theory. The hsab concept is an acronym for hard and soft acids and bases. Also known as the pearson acid base concept, hsab is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways. We have already pointed out that the affinity that metal ions have for ligands is controlled by size, charge and electronegativity. Hard and soft acids and bases hsab theory hard and soft acids and bases hsab theory is a qualitative concept introduced by ralph pearson to explain the stability of metal complexes and the mechanisms of their reactions. Copper and goldcatalyzed 1,3phosphatyloxy and 1,3halogen migration relay to 1,3dienes.
Although there have been numerous attempts to make the theory quantitative by assigning numbers representing hardness and softness to acids and bases, these have not been particularly. A coherent picture of the hydrogen oxidation and evolution. If these condensed acids contain only one type of acid anhydride, they abd called isopoly acids, and their salts are called isopoly salts. How to decide which part reacts in an ambident nucleophile. Hsab theory the hsab concept is an initialism for hard and soft lewis acids and bases. A polyhedronbased heterometallic mof constructed by hsab theory and sbb strategy. The major aim is to show how various bases work, and from there, how we might optimize the reaction conditions by using different type of bases, according to the specific demands in transition metal catalyzed reactions. Based on hsab parameters, calculated using quantum mechanical methods, hd is a relatively hard low. Applications of bases in transition metal catalyzed.
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