Synthesis and selected properties of nonahalogenated 2-ammonio-decaborate anions and their derivatives substituted at N-centre

0488749 - ÚACH 2019 RIV CH eng J - Článek v odborném periodiku
El Anwar, Suzan - Holub, Josef - Tok, Oleg L. - Jelínek, T. - Růžičková, Z. - Fojt, Lukáš - Šolínová, Veronika - Kašička, Václav - Grüner, Bohumír
Synthesis and selected properties of nonahalogenated 2-ammonio-decaborate anions and their derivatives substituted at N-centre.
Journal of Organometallic Chemistry. Roč. 865, SI (2018), s. 189-199. ISSN 0022-328X. E-ISSN 1872-8561
Grant CEP: GA TA ČR(CZ) TH01020844
Institucionální podpora: RVO:61388980 ; RVO:68081707 ; RVO:61388963
Klíčová slova: Boranes * Borate ions * Capillary electrophoresis * Cluster * Electrochemistry * Halogenations
Obor OECD: Inorganic and nuclear chemistry; Biophysics (BFU-R); Analytical chemistry (UOCHB-X)
Impakt faktor: 2.066, rok: 2018

New preparative methods for halogenation of the cage producing the corresponding [2-NH 3B 10 X 9 ] species (2 to 4 , X = Cl, Br, I) have been developed using halogenations by elemental halogens in a glass pressure vessel. Compared to similar icosahedral species of formulation [1-H 3 N-B 12 X 11 ] (X = Cl, Br), the N-alkylation reactions in 10-vertex series proceed significantly more easily. The reason for this difference is conceivably due to the two orders of magnitude lower basicity of the amino group, with pKa values in the interval from 9.27 to 8.37, and slightly lower steric strain around the reaction centre. Thus methylations with MeI under mild conditions provided the whole series of corresponding quarternary amines of the formulation [2-Me 3 N-B 10 X 9 ] (5 to 7 , X = Cl, Br, I). The effect of the steric strain of the surrounding halogens on the reactivity at the NH 3 centre could then be better seen from reactions with bulkier benzyl bromide. Under comparable conditions, these reactions resulted in the ready formation of disubstituted compounds in case of X = Cl (8 ), mixture of mono and disubstituted derivatives for X = Br (9 , 10 ) or in monosubstited product for X = I (11 ) only. Dibenzyl derivative of the nonaiodinated products (12 ) could be still obtained, however only under more forcing conditions. The single-crystal X-ray diffraction structures of all three polyhalogenated derivatives 2 to 4 are presented along with that for benzyl derivative 10 , spectral and physicochemical properties of these polyhalogenated systems are outlined along with specific insights into specific properties of the NH 3 group.
Trvalý link: http://hdl.handle.net/11104/0284392