Naslov (srp)

Teorijsko ispitivanje elektronske strukture i magnetnih osobina klastera bora

Autor

Đorđević, Slađana, 1993-

Doprinosi

Radenković, Slavko, 1981-
Gutman, Ivan, 1947-
Baranac-Stojanović, Marija, 1971-
Furtula, Boris, 1978-

Opis (eng)

In this doctoral dissertation, electronic structure, and magnetic properties ofhomonuclear and heteronuclear boron clusters were investigated. For quantum-chemicalcalculations DFT and post-HF ab initio methods were used. Inverse sandwich clusters,where the boron ring is stabilized by alkaline-earth metals: M2B6 (M = Be, Mg, Ca, Sr, andBa), Be2B7+, Be6B102- and Be6B11-, were investigated. The studied boron clusters have twocyclically delocalized electrons systems (π and σ). These boron clusters can becharacterized as double aromatic systems based on current density and electrondelocalization indices: cyclically delocalized π and σ electrons induce diatropic currents.The effect of different alkaline-earth metals has been studied through geometrical,energetic, and electronic properties of clusters BeB8 and MgB8.In addition to the mentioned series of clusters in which the monocyclic structure of boronis stabilized by alkaline earth metals, a group of homonuclear boron disk-like clusters wasinvestigated, in order to evaluate a connection between the magnetic properties and thenumber of σ and π electrons in different spin states (singlet and triplet) of these clusters.Aromaticity rules based on the number of electrons (Hückel, Baird, …) are widely used inorganic chemistry. It was shown that predictions of the magnetic properties of the studiedclusters can be successfully rationalized by generalized electron-counting rules: Hickel,Baird and Mandado's rules. In most cases, magnetic responses of all subsystems can berationalized with electron-counting rules, but there are also examples where thementioned rules are not applicable.

Opis (srp)

U ovoj doktorskoj disertaciji ispitivani su elektronska struktura i magnetne osobinehomonuklearnih i heteronuklearnih klastera bora. Kvantno-hemijski proračuni suurađeni primenom DFT i post-HF ab initio metoda. Ispitivana je serija klastera oblikainverznog sendviča, u kojima je ciklična struktura atoma bora stabilizovana atomimazemnoalkalnih metala: M2B6 (M = Be, Mg, Ca, Sr i Ba), Be2B7+, Be6B102-i Be6B11-. Nađeno jeda proučavani klasteri bora imaju dva ciklično delokalizovana elektronska sistema (π i σ).Na osnovu izračunatih gustina struje i indeksa koji mere cikličnu delokalizaciju elektrona,nađeno je da ispitivani klasteri bora predstavljaju dvostruko aromatične sisteme: cikličnodelokalizovani π i σ elektronski sistemi mogu da indukuju dijatropne struje. Efekatprisustva različitih atoma zemnoalkalnih metala detaljno je proučen upoređivanjemgeometrijskih, energetskih i elektronskih osobina klastera BeB8 i MgB8.Pored pomenute serije klastera u kojima je monociklična struktura bora stabilizovanaatomima zemnoalkalnih metala, ispitivana je grupa homonuklearnih klastera bora oblikadiska, sa ciljem da se nađe opšta veza između magnetnih osobina i broja σ i π elektrona urazličitim spinskim stanjima (singletnom i tripletnom) ovih klastera. Pravilaaromatičnosti zasnovana na broju elektrona (Hikelovo, Berdovo,…) imaju veliku primenuu organskoj hemiji. Pokazalo se da se predviđanja magnetnih osobina ispitivanih klasteramogu uspešno uraditi generalizacijom postojećih pravila zasnovanih na broju elektrona:Hikelovo, Berdovo i Mandadovo pravilo. U najvećem broju slučajeva navedena praviladaju dobra predviđanja, ali nađeni su i primeri gde navedena pravila nisu primenjiva.

Opis (srp)

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Jezik

srpski

Datum

2023

Licenca

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