Cooperative interaction of protonated hexamethylenetetramine with a hexaarylbenzene-based receptor: experimental and theoretical study

0375066 - ÚMCH 2013 RIV NL eng J - Článek v odborném periodiku
Makrlík, E. - Toman, Petr - Vaňura, P. - Rathore, R.
Cooperative interaction of protonated hexamethylenetetramine with a hexaarylbenzene-based receptor: experimental and theoretical study.
Journal of Molecular Structure. Roč. 1014, APR 25 (2012), s. 7-11. ISSN 0022-2860. E-ISSN 1872-8014
Grant CEP: GA ČR(CZ) GAP205/10/2280
Výzkumný záměr: CEZ:AV0Z40500505
Klíčová slova: extraction * DFT * complexation
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 1.404, rok: 2012

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium HL+(aq)+1.Cs+(nb) reversible arrow 1.HL+(nb)+Cs+(aq) taking place in the two-phase water–nitrobenzene system (HL+ = protonated hexamethylenetetramine, 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (HL+, 1.Cs+) = 0.5 ± 0.1. Further, the stability constant of the 1.HL+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as logβnb (1.HL+) = 5.8 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of the 1.HL+ complex species, which are obviously in a dynamic equilibrium, were indicated. In both of these structures of the resulting complex 1.HL+ having C3 symmetry, the cation HL+ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom of the parent receptor 1 via cation–π interaction.
Trvalý link: http://hdl.handle.net/11104/0006918