Publication detail

Electrophilic Halogenation of closo-1,2-C2B8H10

Year: 2017

Type of publication: článek v odborném periodiku

Name of source: Inorganic Chemistry

Publisher name: American Chemical Society

Place: Washington

Page from-to: 5971-5975

Titles:

Language	Name	Abstract	Keywords
cze	Elektrofilní halogenace closo-1,2-C2B8H10 sloučeniny	Počáteční studia elektrofilní halogenace dicarbaboranu closo-1,2-C2B8H10 (1) odhalila, že substituce probíhá na vrcholech B7 a B10, která jsou vzdálená od CH pozic. Průběh halogenace je silně závislý na povaze halogenačních činidel a reakčních podmínkách. Jednotlivé reakce vedly k izolování monosubstituovaných sloučenin 1,2-C2B8H9-10-X (2) (kde X = F, I) a 1,2-C2B8H9-7-X (3) (kde X = Cl, I). Disubstituované karborany 1,2-C2B8H8-7,10-X2 (4) (kde X = Cl, Br, I) byly získány za více násilných podmínek. Jednotlivé halogenové deriváty byly charakterizovány hmotnostní spektrometrií a high-field NMR (B-11, H-1,C-13) spektroskopií v kombinaci s dvourozměrnými [11B11B]-COSY, H-1{B-11(selektivními)}, a [B-11-H-1]-korelačními NMR technikami. Všechny deriváty nesoucí halogenový substituent v B10 pozici vykazují pozoruhodné opačné C-13 a H-1 NMR stínění v CH1 vrcholu, vzrůstající v řadě H < I < Br < Cl < F. Struktury derivátů 1,2-C2B8H8-7,10-X2 (kde X = Cl, I, 4b,d) byly stanoveny rentgenovou difrakční analýzou.
eng	Electrophilic Halogenation of closo-1,2-C2B8H10	Initial studies on electrophilic halogenation of the dicarbaborane closo-1,2-C2B8H10 (1) have been carried out to reveal that the substitution takes place at B7 and B10 vertexes, which are the most removed from the CH positions. The course of the halogenation is strongly dependent on the nature of the halogenation agent and reaction conditions. Individual reactions led to the isolation of the monosubstituted compounds 1,2-C2B8H9-10-X (2) (where X = F, I) and 1,2-C2B8H9-7-X (3) (where X = Cl, I). Disubstituted carboranes 1,2-C2B8H8-7,10-X2 (4) (where X = Cl, Br, I) were obtained under more forcing conditions. Individual halo derivatives were characterized by mass spectrometry and high-field NMR (B-11, H-1,C-13) spectroscopy combined with two-dimensional [11B11B]-COSY, H-1{B-11(selective)}, and [B-11-H-1]-correlation NMR techniques. All of the derivatives bearing a halogen substituent in the B10 position exhibit a remarkable antipodal C-13 and H-1 NMR shielding at the CH1 vertex, increasing in the order H < I < Br < Cl < F. The structures of 1,2-C2B8H8-7,10-X2 derivatives (where X = Cl, I, 4b,d) were established by X-ray diffraction analyses.	molecular-structure; ortho-carboranes; spectroscopy; fluorination; diffraction; derivatives; route

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